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1
Jackson, T. A., M. O’Callaghan, and T. R. Glare. "Safe Use of Replicating Bacteria in Biological Control." Research Challenges and Needs for Safe Use of Microbial Organisms 79, no. 4 (April 12, 2005): 50–55. http://dx.doi.org/10.7202/706157ar.
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Naturally occurring entomopathogenic bacteria provide an important resource for pest control. Greatest benefit will be obtained from the application of replicating bacteria which can establish in the host's environment and provide long term control. Bacteria developed for pest control are required to be safety tested and registered, yet bacteria are frequently introduced into the environment to enhance plant growth or aid soil processes without regulation. Why then, is the use of insect pathogenic bacteria treated differently? Augmentation of bacteria already present in the environment is unlikely to have any unwanted side effects as application is only changing the spatial and temporal distribution of the microbe and will have little long term effect on the total population. Users of the bacteria, however, will be exposed to the bacterium at a level higher than experienced naturally and potential adverse effects of this interaction should be addressed through Tier 1 safety testing. Non-target organisms should also be tested. If new organisms (exotic strains or modified bacteria) are to be introduced to the environment, their potential effects on the environment should be considered. The question of horizontal gene flow from applied bacteria also needs to be addressed. A better understanding of microbial ecology and Systems for tracking new strains and genes are essential to develop appropriate assessment procedures to ensure the safe utilisation of bacteria in biological control.
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Bording-Jorgensen, M., T. Gartke, H. Armstrong, and E. Wine. "A50 IMPACT OF SHORT CHAIN FATTY ACIDS ON PATHOGENICTY OF COMMENSAL BACTERIA IN PEDIATRIC INFLAMMATORY BOWEL DISEASES." Journal of the Canadian Association of Gastroenterology 5, Supplement_1 (February 21, 2022): 57–58. http://dx.doi.org/10.1093/jcag/gwab049.049.
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Abstract Background Dietary fibers are fermented by microbiota into many different compounds including short-chain fatty acids (SCFA). The gut microenvironment is essential not only for human health but also in maintaining a rich biodiversity of bacterial species. It is well known that the microbiome is altered in Inflammatory Bowel Diseases (IBD), which likely changes the microenvironment and has other health effects on individuals with IBD. Pathobionts are organisms that can induce pathology under specific conditions, and several have already been associated with IBD, such as adherent invasive Escherichia coli (AIEC) and Helicobacter hepaticus. Although these bacteria have been associated with IBD, it is still largely unknown what conditions make these bacteria become pathogenic. Aims Determine the role of SCFA composition on the pathogenic potential of commensal bacteria isolated from non-IBD and IBD pediatric patients. Methods Anaerobic bacteria were isolated during colonoscopy from pediatric IBD and non-IBD patients and identified using 16S sequencing. PMA-activated human monocytes (THP-1) and colonic epithelial cells (Caco2) were grown in the presence of SCFA (acetate, butyrate, formate, propionate, and succinate). The ability of commensal bacteria ( Bacteroides fragilis, Clostridium innocuum, Ruminococcus, Parabacteroides merdae, Bifidobacterium infantis and E. coli HB101) and the pathobiont AIEC to invade cells was assessed using a gentamicin protection assay. Immune activation was quantified with IL-1b and IL-6 by ELISA, as well as reactive oxygen species (ROS) using DCFDHA. Results The SCFA propionate and formate significantly decreased invasion for HB101 and LF82 into macrophages but not epithelial cells. Bacteria isolated from an IBD environment had a higher invasion potential independent of the addition of SCFA, compared to bacteria from a non-IBD environment. However, butyrate was found to significantly increase invasion of non-IBD B. fragilis into Caco2 cells but not macrophages. Bacteria isolated from IBD patients tended to have a higher inflammatory response with both elevated IL-1b as well as ROS production. Conclusions Microenvironment changes, such as in SCFA concentrations, during a disease state can affect the host response to microbes including commensals. Commensal bacteria from IBD patients tend to be more proinflammatory, suggesting that they play a role in driving inflammation. SCFA are beneficial factors for gut health; however, what is still unknown is the interaction between microbes and the host after microenvironmental shifts that likely causes bacterial stress. Understanding the host-microbe interactions and the role diet can have on this dynamic relationship has the potential for discovering new therapeutic options for those suffering from IBD. Funding Agencies CIHRWeston Family Foundation
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Trinchieri, Giorgio. "Innate Immune Signaling in Regulation of Immunity." Blood 128, no. 22 (December 2, 2016): SCI—26—SCI—26. http://dx.doi.org/10.1182/blood.v128.22.sci-26.sci-26.
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Abstract Innate resistance, as an integral part of inflammation, and adaptive immunity participate in oncogenesis and tumor surveillance. For a long time, innate resistance was considered a primitive nonspecific form of resistance to infections that was eclipsed by the potent and specific acquired immunity of higher organisms. More recently, it has been recognized that innate resistance is not only the first line of defense against infections but also sets the stage and is necessary for the development of adaptive immunity. Advances in cancer biology have revealed that the defensive mechanisms of innate resistance and inflammation are indeed manifestations of tissue homeostasis and control of cellular proliferation that have many pleiotropic effects on carcinogenesis and tumor progression and dissemination. The interaction of innate and adaptive immunity with carcinogenesis and tumor progression is complicated and results in effects that either favor or impede tumor progression. Innate immune receptors both sense and regulate the composition of the microbiota, the large number of commensal microorganisms that colonize the barrier surfaces of all multicellular organisms, including those of humans. The microbiota affects many functions of our body and the two together comprise one metaorganism. Microbial imbalance particularly in the gut plays a critical role in the development of multiple diseases, such as cancer, autoimmune conditions and increased susceptibility to infection. Alteration in innate immune signaling and immunity may change the composition of the microbiota affecting tumor initiation both at the barrier sites (e.g. in the gut) and systemically. The commensal microbes not only may affect the development and progression of cancer but they have also important effects on the response to cancer therapy. Mostly through their interaction with innate receptors, commensal microorganisms modulate the ability of the organism to respond to cancer immunotherapy and chemotherapy by affecting the threshold of response of tumor-associated myeloid cells and their ability to sustain anti-tumor immunity. Disclosures No relevant conflicts of interest to declare.
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Scherlach, Kirstin, and Christian Hertweck. "Chemical Mediators at the Bacterial-Fungal Interface." Annual Review of Microbiology 74, no. 1 (September 8, 2020): 267–90. http://dx.doi.org/10.1146/annurev-micro-012420-081224.
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Interactions among microbes are key drivers of evolutionary progress and constantly shape ecological niches. Microorganisms rely on chemical communication to interact with each other and surrounding organisms. They synthesize natural products as signaling molecules, antibiotics, or modulators of cellular processes that may be applied in agriculture and medicine. Whereas major insight has been gained into the principles of intraspecies interaction, much less is known about the molecular basis of interspecies interplay. In this review, we summarize recent progress in the understanding of chemically mediated bacterial-fungal interrelations. We discuss pairwise interactions among defined species and systems involving additional organisms as well as complex interactions among microbial communities encountered in the soil or defined as microbiota of higher organisms. Finally, we give examples of how the growing understanding of microbial interactions has contributed to drug discovery and hypothesize what may be future directions in studying and engineering microbiota for agricultural or medicinal purposes.
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Ellul, S., P. Rausch, A. PIsani, C. Bang, P. Ellul, and A. Franke. "P688 Association of Akkermansia muciniphila with a healthy gut microbiome." Journal of Crohn's and Colitis 15, Supplement_1 (May 1, 2021): S606—S607. http://dx.doi.org/10.1093/ecco-jcc/jjab076.808.
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Abstract Background Comprehensive knowledge of the types and ratios of microbes present in the healthy gastrointestinal human gut is required before any study is attempted to alter the microbiome to treat one condition. Akkermansia muciniphila, a mucin-degrading bacterium, belonging to the phylum Verrucomicrobia, has been inversely associated with inflammation and diabetes whilst it has been internationally proposed as one of the contributors for maintaining a healthy gut and glucose homeostasis. Studies noted that higher amounts of this microorganism in the gut microbiota was linked to a metabolically healthier lifestyle; therefore, linking an interaction between the gut bacterial richness and abundance of A. muciniphila. This organism was noted to improve the gut barrier using its outer membrane protein Amuc 1100, which seems to interact with Toll-like receptor 2, whilst potentially adhering to intestinal epithelial cells, leading its role in balancing the human immunological homeostasis whilst strengthening the monolayer integrity of the wall. The aim of this study was to assess if there is any difference in the presence of Akkermansia muciniphila between IBD patients and controls. Methods Faecal microbiota from newly diagnosed treatment naïve IBD patients and controls were analysed via the bacterial 16s rRNA gene sequencing on illumine MiSeq. Results 100 patients with IBD and 97 controls were recruited. Forty-one different ASVs were identified from our cohort, all of which being differentially abundant between the different health conditions present. From these, 20 ASVs such as ASV-14 G-Alistipes uncl., and ASV 20-Akkermansia muciniphila, were found to be more abundant in healthy individuals than in IBD patients. There was no dietary association. Conclusion In this study Akkermansia muciniphila was significantly found in higher amount in the healthy control population than in the IBD cohort. The potential role of repopulating the gut bacteria with Akkermansia muciniphila needs to be investigated as to reduce the burden of disease, medications prescribed and the clinical outcome.
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Jain, Akansha, and Sampa Das. "Insight into the Interaction between Plants and Associated FluorescentPseudomonasspp." International Journal of Agronomy 2016 (2016): 1–8. http://dx.doi.org/10.1155/2016/4269010.
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FluorescentPseudomonasare known for their plant growth promoting and disease protection abilities. In past years, a number of studies have focused on how these bacteria suppress disease and induce resistance. They are known to produce antibiotics and siderophores, promote growth, and induce systemic resistance in the host plant. This bacterium has come out as a model organism for ecological studies going on in rhizosphere and for studying plant-beneficial microbe interaction. This review focuses on the current state of knowledge on biocontrol potential of fluorescentPseudomonasstrains and the mechanisms adopted by them.
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K.S, Vidhya Bharathi, Djanaguiraman M, Raghu R, Jeyakumar P, and Karthikeyan s. "Evaluation of Ecotoxicity of Nanoceria to Organisms of Different Trophic Levels." Madras Agricultural Journal 108, March (2021): 1–5. http://dx.doi.org/10.29321/maj.10.000490.
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he present study was aimed at evaluation of the toxicity potential of nanoceria on phosphobacteria (Bacillus megaterium ; soil ecosystem), azolla (Anabaena azollae and microalgae ; Aquatic ecosystem) and sorghum (Sorghum bicolor (L.) Moench) pollen grain and photosystem (PS) II quantum yield (terrestrial ecosystem). The study examined the differences in toxicity among a different concentration of nanoceria to each organism and differences in toxicity among the organisms. In each toxicity experiment, the concentration of nanoceria used are 0, 5, 10, 25, 50, 100, 200, 400, 500, and 1000 mg L-1. The result indicated that nanoceria is not toxic to soil microbes, aquatic organisms and terrestrial plants at lower concentration (up to 25 mg L-1). However, above 25 mg L-1 concentration, differential responses between nanoceria and organisms were observed. Higher concentration (500 and 1000 mg L-1) inhibited the growth of phosphobacteria, microalgae, and pollen germination and PS II quantum yield. The adverse effect caused by nanoceria could be associated with the concentration of nanoceria, differences in interactions with the cell with nanoceria, and oxidative damage caused by nanoceria. Among the assays, pollen germination was found to be more sensitive to the nanoceria in the medium, followed by photosystem II quantum yield.
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Park, Stacy J., and Borna Mehrad. "Innate Immunity to Aspergillus Species." Clinical Microbiology Reviews 22, no. 4 (October 2009): 535–51. http://dx.doi.org/10.1128/cmr.00014-09.
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SUMMARY All humans are continuously exposed to inhaled Aspergillus conidia, yet healthy hosts clear the organism without developing disease and without the development of antibody- or cell-mediated acquired immunity to this organism. This suggests that for most healthy humans, innate immunity is sufficient to clear the organism. A failure of these defenses results in a uniquely diverse set of illnesses caused by Aspergillus species, which includes diseases caused by the colonization of the respiratory tract, invasive infection, and hypersensitivity. A key concept in immune responses to Aspergillus species is that the susceptibilities of the host determine the morphological form, antigenic structure, and physical location of the fungus. In this review, we summarize the current literature on the multiple layers of innate defenses against Aspergillus species that dictate the outcome of this host-microbe interaction.
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Weitzman, Chava L., Karen Gibb, and Keith Christian. "Skin bacterial diversity is higher on lizards than sympatric frogs in tropical Australia." PeerJ 6 (November 14, 2018): e5960. http://dx.doi.org/10.7717/peerj.5960.
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Animal skin acts as a barrier between the organism and its environment and provides the first line of defense against invading pathogens. Thus, skin surfaces harbor communities of microbes that are interacting with both the host and its environment. Amphibian skin bacteria form distinct communities closely tied to their host species, but few studies have compared bacterial communities between amphibians and other, non-amphibian sympatric animals. Notably, skin microbes on reptiles have gained little attention. We used next-generation sequencing technology to describe bacterial communities on the skin of three lizard species and compared them to bacteria on six cohabiting frog species in the Northern Territory of Australia. We found bacterial communities had higher richness and diversity on lizards than frogs, with different community composition between reptiles and amphibians and among species. Core bacteria on the three lizard species overlapped by over 100 operational taxonomic units. The bacterial communities were similar within species of frogs and lizards, but the communities tended to be more similar between lizard species than between frog species and when comparing lizards with frogs. The diverse bacteria found on lizards invites further questions on how and how well reptiles interact with microorganisms through their scaly skin.
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Han, Lu, and Qi Wang. "Association of Dietary Live Microbe Intake with Cardiovascular Disease in US Adults: A Cross-Sectional Study of NHANES 2007–2018." Nutrients 14, no. 22 (November 20, 2022): 4908. http://dx.doi.org/10.3390/nu14224908.
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Objective: To detect the potential association between dietary live microbe and cardiovascular diseases (CVD). Methods: Data of 10,875 participants aged 18 years or older in this study were collected from the National Health and Nutrition Examination Survey (NHANES). Participants in this study were divided into three groups according to the Sanders dietary live microbe classification system: low, medium, and high dietary live microbe groups. CVD was defined by a combination of self-reported physician diagnoses and standardized medical status questionnaires. The analyses utilized weighted logistic regression models. Results: After the full adjustment for confounders, patients in the medium dietary live microbe group had a low prevalence of CVD in contrast to those in the low dietary live microbe group (OR: 0.78, 95% CI: 0.52–0.99, and p < 0.05), but no significant association with CVD was detected between the high and low dietary live microbe groups. Higher dietary live microbe groups were negatively associated with the prevalence of stroke (p for trend = 0.01) and heart attack (p for trend = 0.01). People who were male were more likely to suffer stroke due to low dietary live microbe (p for interaction = 0.03). Conclusion: A high dietary live microbe intake was associated with a low prevalence of CVD, and the significant association was detected when the analysis was limited to stroke and heart attack.
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YANDIGERI, Mahesh S., Manoj Kumar SOLANKI, Sudheer KUMAR, Rajesh Kumar SINGH, and Alok K. SRIVASTAVA. "Nutrient Competition Mediated Antagonism of Microbes Against Rhizoctonia solani." Notulae Scientia Biologicae 10, no. 3 (September 27, 2018): 392–99. http://dx.doi.org/10.15835/nsb10310312.
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Plant growth-promoting (PGP) microorganisms are beneficial soil micro creatures which may facilitate plant growth by direct or indirect ways. Bacillus amyloliquefaciens MB101 (BA), Streptomyces atrovirens N23 (SA) and Hypocrea lixii NAIMCC-F-01760 (HL) were earlier reported to have the ability to manage the tomato root rot disease caused by Rhizoctonia solani (RS) at some extent. In the present study, effect of nutrient supplementation like potato dextrose broth (PDB) and tomato root extract (TRE) on antagonism of these three microbes was characterized under the soil microcosm in order to understand the role of nutrient in microbe-microbe interaction. A moderate influence on the population of all three antagonists was resulted by PDB and TRE with RS. However, TRE and PDB were causing a significant impact on cell wall degrading enzymes and antifungal activity in the presence of RS. Moreover, hyphal degradation of RS was proved by scanning electron micrographs in the absence of substrates. Nutrient competition enhanced the call wall degrading enzyme production. Therefore, the present study concluded the role of substrate in the mycoparasitism and also sustain the potential of the hereby methodology (soil microcosm) for screening of other soil-inhibiting organism in the future.
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Azevedo, Maria Manuel, Cidália Pina-Vaz, and Fátima Baltazar. "Microbes and Cancer: Friends or Faux?" International Journal of Molecular Sciences 21, no. 9 (April 28, 2020): 3115. http://dx.doi.org/10.3390/ijms21093115.
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Cancer is one of the most aggressive and deadly diseases in the world, representing the second leading cause of death. It is a multifactorial disease, in which genetic alterations play a key role, but several environmental factors also contribute to its development and progression. Infections induced by certain viruses, bacteria, fungi and parasites constitute risk factors for cancer, being chronic infection associated to the development of certain types of cancer. On the other hand, susceptibility to infectious diseases is higher in cancer patients. The state of the host immune system plays a crucial role in the susceptibility to both infection and cancer. Importantly, immunosuppressive cancer treatments increase the risk of infection, by decreasing the host defenses. Furthermore, alterations in the host microbiota is also a key factor in the susceptibility to develop cancer. More recently, the identification of a tumor microbiota, in which bacteria establish a symbiotic relationship with cancer cells, opened a new area of research. There is evidence demonstrating that the interaction between bacteria and cancer cells can modulate the anticancer drug response and toxicity. The present review focuses on the interaction between microbes and cancer, specifically aiming to: (1) review the main infectious agents associated with development of cancer and the role of microbiota in cancer susceptibility; (2) highlight the higher vulnerability of cancer patients to acquire infectious diseases; (3) document the relationship between cancer cells and tissue microbiota; (4) describe the role of intratumoral bacteria in the response and toxicity to cancer therapy.
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Zinöcker, Marit, and Inge Lindseth. "The Western Diet–Microbiome-Host Interaction and Its Role in Metabolic Disease." Nutrients 10, no. 3 (March 17, 2018): 365. http://dx.doi.org/10.3390/nu10030365.
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The dietary pattern that characterizes the Western diet is strongly associated with obesity and related metabolic diseases, but biological mechanisms supporting these associations remain largely unknown. We argue that the Western diet promotes inflammation that arises from both structural and behavioral changes in the resident microbiome. The environment created in the gut by ultra-processed foods, a hallmark of the Western diet, is an evolutionarily unique selection ground for microbes that can promote diverse forms of inflammatory disease. Recognizing the importance of the microbiome in the development of diet-related disease has implications for future research, public dietary advice as well as food production practices. Research into food patterns suggests that whole foods are a common denominator of diets associated with a low level of diet-related disease. Hence, by studying how ultra-processing changes the properties of whole foods and how these foods affect the gut microbiome, more useful dietary guidelines can be made. Innovations in food production should be focusing on enabling health in the super-organism of man and microbe, and stronger regulation of potentially hazardous components of food products is warranted.
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Wang, Qianhong, Zheng Hao, Ruirui Ding, Huabing Li, Xiangming Tang, and Feizhou Chen. "Host Dependence of Zooplankton-Associated Microbes and Their Ecological Implications in Freshwater Lakes." Water 13, no. 21 (October 20, 2021): 2949. http://dx.doi.org/10.3390/w13212949.
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Zooplankton is colonized by quite different microbes compared with free-living and particle-associated bacteria, serving as a non-negligible niche of bacteria in aquatic ecosystems. Yet detailed analysis of these bacterial groups is still less known, especially in freshwater lakes. To widen our knowledge of host-microbe interaction and bacterial ecosystem functions, we chose two specific populations of zooplankton, i.e., cladoceran Moina and copepod Calanoids, as hosts from five natural lakes, and illustrated detailed features of their associated bacteria. Through 16S rRNA gene sequencing, we found microbes colonized on Calanoids presented significantly higher α-diversity, stronger bacterial interaction and metabolic function potentials than for Moina. It was also notable that zooplankton-associated bacteria showed a high potential of fatty acid metabolism, which is beneficial for host’s development. Moreover, we found that zooplankton-associated microbes may exert profound effects on biogeochemical cycles in freshwater lakes, since several bacterial members able to participate in carbon and nitrogen cycles were found abundant. Overall, our study expands current understanding of the host-microbe interaction and underlying ecological dynamics in freshwater ecosystem.
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Tripathy, Manas K., Renu Deswal, and Sudhir K. Sopory. "Plant RABs: Role in Development and in Abiotic and Biotic Stress Responses." Current Genomics 22, no. 1 (April 12, 2021): 26–40. http://dx.doi.org/10.2174/1389202922666210114102743.
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Endosomal trafficking plays an integral role in various eukaryotic cellular activities and is vital for higher-order functions in multicellular organisms. RAB GTPases are important proteins that influence various aspects of membrane traffic, which consequently influence many cellular functions and responses. Compared to yeast and mammals, plants have evolved a unique set of plant-specific RABs that play a significant role in their development. RABs form the largest family of small guanosine triphosphate (GTP)-binding proteins, and are divided into eight sub-families named RAB1, RAB2, RAB5, RAB6, RAB7, RAB8, RAB11 and RAB18. Recent studies on different species suggest that RAB proteins play crucial roles in intracellular trafficking and cytokinesis, in autophagy, plant microbe interactions and in biotic and abiotic stress responses. This review recaptures and summarizes the roles of RABs in plant cell functions and in enhancing plant survival under stress conditions.
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Tseng, Michelle, Evgeniya Yangel, and Yi Lin Zhou. "Herbivory alters thermal responses of algae." Journal of Plankton Research 41, no. 5 (September 2019): 641–49. http://dx.doi.org/10.1093/plankt/fbz043.
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Abstract The temperature-size rule (TSR) describes the widespread pattern in which organisms grown at higher temperatures mature at smaller adult sizes, or exhibit smaller cell sizes in the case of microbes. Although the TSR has been shown in a wide range of taxa, most TSR studies have been conducted in the absence of species interactions such as competitors, parasites or predators. Given that these interactions are ubiquitous in nature, here we examine how the presence of a live herbivore (Daphnia pulex) affects the response of a cosmopolitan green algae (Scenedesmus obliquus) to the thermal environment. In the absence of direct herbivory, algae exhibited the characteristic TSR, exhibiting smaller cells, and smaller colonies at higher temperatures. However, in the presence of Daphnia herbivory, we saw no evidence of the TSR. Rather, both cell and colony size were uniform across the three rearing temperatures. These results suggest that Daphnia consume larger-sized algae at cooler temperatures, and smaller-sized algae at higher temperatures. Overall this study demonstrates that species interactions such as herbivory can alter the response of primary producers to the thermal environment, and suggests that the TSR may be readily modified in the natural world, where predators, herbivores and competitors abound.
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LINDÉN, Sara, Jafar MAHDAVI, Jan HEDENBRO, Thomas BORÉN, and Ingemar CARLSTEDT. "Effects of pH on Helicobacter pylori binding to human gastric mucins: identification of binding to non-MUC5AC mucins." Biochemical Journal 384, no. 2 (November 23, 2004): 263–70. http://dx.doi.org/10.1042/bj20040402.
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Helicobacter pylori causes gastritis, peptic ulcer disease and gastric cancer. The microbe is found in the gastric mucus layer where a pH gradient ranging from acidic in the lumen to neutral at the cell surface is maintained. The aim of the present study was to investigate the effects of pH on H. pylori binding to gastric mucins from healthy individuals. At pH 3, all strains bound to the most charged MUC5AC glycoform and to a putative mucin of higher charge and larger size than subunits of MUC5AC and MUC6, irrespective of host blood-group. In contrast, at pH 7.4 only Leb-binding BabA-positive strains bound to Leb-positive MUC5AC and to smaller mucin-like molecules, including MUC1. H. pylori binding to the latter component(s) seems to occur via the H-type-1 structure. All strains bound to a proteoglycan containing chondroitin sulphate/dermatan sulphate side chains at acidic pH, whereas binding to secreted MUC5AC and putative membrane-bound strains occurred both at neutral and acidic pH. The binding properties at acidic pH are thus common to all H. pylori strains, whereas mucin binding at neutral pH occurs via the bacterial BabA adhesin and the Leb antigen/related structures on the glycoprotein. Our work shows that microbe binding to membrane-bound mucins must be considered in H. pylori colonization, and the potential of these glycoproteins to participate in signalling events implies that microbe binding to such structures may initiate signal transduction over the epithelial layer. Competition between microbe binding to membrane-bound and secreted mucins is therefore an important aspect of host–microbe interaction.
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Zenir, Madeleine C., Marina López-Pozo, Stephanie K. Polutchko, Jared J. Stewart, William W. Adams, Adam Escobar, and Barbara Demmig-Adams. "Productivity and Nutrient Quality of Lemna minor as Affected by Microbiome, CO2 Level, and Nutrient Supply." Stresses 3, no. 1 (December 31, 2022): 69–85. http://dx.doi.org/10.3390/stresses3010007.
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Rising atmospheric carbon dioxide (CO2) levels can impact plant photosynthesis and productivity and threaten food security, especially when combined with additional environmental stressors. This study addresses the effects of elevated CO2 in combination with low nutrient supply on Lemna minor (common duckweed). We quantified plant growth rate and nutritional quality (protein content) and evaluated whether any adverse effects of elevated CO2, low nutrients, or the combination of the two could be mitigated by plant-microbe interaction. Plants were grown under controlled conditions and were either uninoculated or inoculated with microorganisms from a local pond that supported L. minor populations. Under low nutrients in combination with high CO2, growth (plant area expansion rate) decreased and biomass accumulation increased, albeit with lower nutritional quality (lower percentage of protein per plant biomass). Inoculation with plant-associated microorganisms restored area expansion rate and further stimulated biomass accumulation while supporting a high protein-to-biomass ratio and, thus, a high nutritional quality. These findings indicate that plant-microbe interaction can support a higher nutritional quality of plant biomass under elevated atmospheric CO2 levels, an important finding for both human and non-human consumers during a time of rapid environmental change.
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Gan, Lin, Hui Zhao, Aili Wang, Sanshan Li, Jia Liu, and Liuyan Yang. "Pseudomonas putida inoculation promotes submerged plant Vallisneria natans growth by carbon conversion in a plant–microbe interaction." Marine and Freshwater Research 69, no. 5 (2018): 851. http://dx.doi.org/10.1071/mf17117.
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Submerged plant growth is limited by the reduction of underwater photosynthesis attributed to low CO2 availability, as well as light limitation associated with underwater conditions. Heterotrophic bacteria and fungi play an important role in local aqueous dissolved inorganic carbon (DIC) content surrounding submerged plants. In order to investigate the effects of carbon conversion in plant–microbe interactions on plant growth, in the present study we inoculated the plant medium of Vallisneria natans with Pseudomonas putida KT2440 and measured carbon conversion in the system, as well as several indices of plant growth. The quantity of P. putida KT2440 increased twofold because of the availability of organic matter produced by V. natans. Similarly, P. putida KT2440 supplied DIC for V. natans, improving its photosynthetic rate. Moreover, the significantly higher leaf area, specific leaf area and fresh biomass of V. natans attributed to the presence of P. putida KT2440 demonstrated that the interaction between V. natans and P. putida enhanced the efficiency of nutrient and CO2 uptake by V. natans, promoting V. natans growth. Therefore, we suggest that the carbon and oxygen microcycle based on the protocooperation of V. natans and P. putida KT2440 may accelerate the transformation of carbon to increase carbon availability to promote the growth of both plant and microbe.
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Aziz, M. A. A., N. M. I. Othman, and N. B. Kamaruzaman. "A Review on Bacteria, Fungi and Dual Inoculation Towards Nitrogen Fixation in Oil Palm Plants." IOP Conference Series: Earth and Environmental Science 1059, no. 1 (July 1, 2022): 012030. http://dx.doi.org/10.1088/1755-1315/1059/1/012030.
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Abstract Oil palm plantation sector is the most important contribution to economic growth in most Asian countries and most plantations rely on chemical fertilizer for growth which caused harmful to environment. As we can see, nitrogen in the atmosphere can be fixed by the microorganism through the process of nitrogen fixation where it also can act as a bio-fertilizer. Therefore, three objectives are covered in this study, which 1) to review studies on microbial activities and their interaction with plant in soil, 2) to evaluate the effectiveness of organic matter that enhance microbe activity and also N-fixation and 3) to identify the species of bacteria and fungi used for oil palm inoculation in previous studies. A review of microbial activity has been presented in order to highlight the potential interaction where endophytic BNF bacteria have successfully increase the development of oil palm seedlings. Combination of EFB and cow dung in vermicompost technique showed the higher number of E. eugeniae (32 earthworms) thus increases available plant nitrogen. Microbial inoculation such as Glomus aggregatum, Bacillus salmalaya strain 139SI and Herbaspirillum seropedicae gives positive impact towards growth performance. The findings provided successful significant proof that microbe inoculation has a favorable influence on oil palm FFB production.
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Yan, Di, Hsin-Wen Chang, Rasnik Singh, Kevin Lai, Kristina Lee, Ladan Afifi, Xueyan Lu, Derya Ucmak, and Susan Lynch. "2296." Journal of Clinical and Translational Science 1, S1 (September 2017): 15. http://dx.doi.org/10.1017/cts.2017.68.
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OBJECTIVES/SPECIFIC AIMS: Psoriasis is one of the most common inflammatory diseases of the skin, affecting about 2%–3% of the US population. Despite its high prevalence, its pathogenesis remains poorly understood. The ability of the microbiome to modify host immunity and metabolism suggests that it may contribute to the development of psoriasis and its cardiometabolic comorbidities. This study aims to characterize the psoriatic skin microbiome and understand the functional role that these bacteria may play. METHODS/STUDY POPULATION: 16s rRNA sequencing of site-matched skin swabs from 8 psoriasis patients and 8 healthy controls was used to identify bacteria and determine their relative abundance and microbial community diversity in the sample. PICRUSt was used to infer the functional roles of the bacteria from 16s rRNA amplicon data. RESULTS/ANTICIPATED RESULTS: Lesional psoriasis skin had lower α diversity (p=0.04), less Actinobacteria (p=0.0001), but higher Firmicutes (p=0.009) compared with controls. At the genus level, lesional skin had more Alloiococcus (p=0.01) and Aerococcus (p=0.01) and demonstrated a trend towards lower Propionibacterium (p=0.08) and higher Gallicola (p=0.09) compared to controls. Interestingly, Alloiococcus (p=0.003) and Gallicola (p=0.04) were also higher in nonlesional skin compared with controls. Furthermore, lesional and nonlesional skin shared an increased abundance of Acinetobacter sp., Staphylococcus pettenkoferi, and Streptococcus sp., relative to controls. Lesional and nonlesional psoriasis skin did not differ significantly in microbiome composition. Predictive functional analysis revealed that both the healthy and psoriatic skin microbiome were enriched with bacteria capable of amino acid and carbohydrate metabolism suggest these functions might have a general role in host-microbe interaction. DISCUSSION/SIGNIFICANCE OF IMPACT: These data reveal intriguing differences in the cutaneous microbiome of psoriatic individuals and healthy controls and suggest that bacterial metabolism may play an important role in host-microbe interaction.
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Messyasz, Adriana, Rebecca L. Maher, Sonora S. Meiling, and Rebecca Vega Thurber. "Nutrient Enrichment Predominantly Affects Low Diversity Microbiomes in a Marine Trophic Symbiosis between Algal Farming Fish and Corals." Microorganisms 9, no. 9 (September 3, 2021): 1873. http://dx.doi.org/10.3390/microorganisms9091873.
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While studies show that nutrient pollution shifts reef trophic interactions between fish, macroalgae, and corals, we know less about how the microbiomes associated with these organisms react to such disturbances. To investigate how microbiome dynamics are affected during nutrient pollution, we exposed replicate Porites lobata corals colonized by the fish Stegastes nigricans, which farm an algal matrix on the coral, to a pulse of nutrient enrichment over a two-month period and examined the microbiome of each partner using 16S amplicon analysis. We found 51 amplicon sequence variants (ASVs) shared among the three hosts. Coral microbiomes had the lowest diversity with over 98% of the microbiome dominated by a single genus, Endozoicomonas. Fish and algal matrix microbiomes were ~20 to 70× more diverse and had higher evenness compared to the corals. The addition of nutrients significantly increased species richness and community variability between samples of coral microbiomes but not the fish or algal matrix microbiomes, demonstrating that coral microbiomes are less resistant to nutrient pollution than their trophic partners. Furthermore, the 51 common ASVs within the 3 hosts indicate microbes that may be shared or transmitted between these closely associated organisms, including Vibrionaceae bacteria, many of which can be pathogenic to corals.
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Paunova-Krasteva, Tsvetelina S., Velichka A. Pavlova, Cristina De Castro, Radka M. Ivanova, Antonio Molinaro, Elena B. Nikolova, and Stoyanka R. Stoitsova. "Cyclic enterobacterial common antigens fromEscherichia coliO157 as microbe-associated molecular patterns." Canadian Journal of Microbiology 60, no. 3 (March 2014): 173–76. http://dx.doi.org/10.1139/cjm-2013-0697.
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In a previous study, we described 2 forms of cyclic enterobacterial common antigen (ECACYC), a tetramer and a pentamer, from Escherichia coli O157. ECACYCis present in several representatives of the Enterobacteriaceae. To date, functional studies on ECACYCare sparse. Cyclic oligosaccharides in other bacteria, like the cyclic β-glucans in Rhizobiaceae, represent microbe-associated molecular patterns involved in host–bacteria interaction. This observation determined the aim of the present study: to test whether the tetrameric and pentameric ECACYCfrom E. coli O157 can be recognised by host humoral and cellular mechanisms. ELISA tests designed to compare the 2 ECACYCwith the O157 lipopolysaccharide showed that both ECACYCwere not recognised by polyclonal anti-O157 serum but were good ligands for mannan-binding lectin. The lectin had a higher affinity for the tetramer than the pentamer. ECACYCdeposited more C3b than did the lipopolysaccharide. To examine the interactions with human circulating neutrophils, the antigens were loaded onto fluorescent latex beads and applied in a phagocytosis experiment. Spheres coated with the 2 ECACYCoccasionally adhered to phagocyte surfaces but, unlike O157-loaded spheres, failed to induce free-radical release. The results show that the 2 ECACYCrepresent microbe-associated molecular patterns recognised by host humoral non-self-recognition mechanisms.
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Ramsey, J. S., J. D. Chavez, R. Johnson, S. Hosseinzadeh, J. E. Mahoney, J. P. Mohr, F. Robison, et al. "Protein interaction networks at the host–microbe interface in Diaphorina citri , the insect vector of the citrus greening pathogen." Royal Society Open Science 4, no. 2 (February 2017): 160545. http://dx.doi.org/10.1098/rsos.160545.
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The Asian citrus psyllid ( Diaphorina citri) is the insect vector responsible for the worldwide spread of ‘ Candidatus Liberibacter asiaticus’ (CLas), the bacterial pathogen associated with citrus greening disease. Developmental changes in the insect vector impact pathogen transmission, such that D. citri transmission of CLas is more efficient when bacteria are acquired by nymphs when compared with adults. We hypothesize that expression changes in the D. citri immune system and commensal microbiota occur during development and regulate vector competency. In support of this hypothesis, more proteins, with greater fold changes, were differentially expressed in response to CLas in adults when compared with nymphs, including insect proteins involved in bacterial adhesion and immunity. Compared with nymphs, adult insects had a higher titre of CLas and the bacterial endosymbionts Wolbachia, Profftella and Carsonella. All Wolbachia and Profftella proteins differentially expressed between nymphs and adults are upregulated in adults, while most differentially expressed Carsonella proteins are upregulated in nymphs. Discovery of protein interaction networks has broad applicability to the study of host–microbe relationships. Using protein interaction reporter technology, a D. citri haemocyanin protein highly upregulated in response to CLas was found to physically interact with the CLas coenzyme A (CoA) biosynthesis enzyme phosphopantothenoylcysteine synthetase/decarboxylase. CLas pantothenate kinase, which catalyses the rate-limiting step of CoA biosynthesis, was found to interact with a D. citri myosin protein. Two Carsonella enzymes involved in histidine and tryptophan biosynthesis were found to physically interact with D. citri proteins. These co-evolved protein interaction networks at the host–microbe interface are highly specific targets for controlling the insect vector responsible for the spread of citrus greening.
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Habib, Sabiha. "Screening of Bacteria for Biosurfactants, Exopolysaccharides and Biofilms and their Impact on Growth Stimulation of Zea mays Grown under Petrol Stress." International Journal of Agriculture and Biology 26, no. 02 (August 1, 2021): 309–16. http://dx.doi.org/10.17957/ijab/15.1839.
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Environmental stress imposed by petroleum hydrocarbons can compensate by use of auxin-producing bacteria having potential for biosurfactants production, to assist improved plants’ growth in petrol contaminated areas. In the present work, four auxin-producing bacteria were screened for biosurfactants, exopolysaccharides (EPS) and biofilms production capability. We hypothesized that Enterobacter sp. (A5C) was the most efficient strain with respect to biosurfactant production and can accumulate EPS as well as biofilms. This strain was attributed to exhibit emulsification index, percentage of hydrophobicity and percentage of hydrocarbon degradation more than 50%. Also, it produced 9.27 mg of EPS per 100 mL of culture while Fourier transform infrared spectroscopy (FTIR) confirmed the presence of alcoholic and carboxylic groups, ketone and sugars in it. Results of in vitro plant microbe interaction assay revealed its potential to stimulate the growth of Zea mays L. plants under 1 and 2% of petrol stress by improving physio-chemical attributes of treated plants, over control. Thus, it is concluded that the test organism i.e., Enterobacter sp. (A5C) might be involved in developing bacterial community (EPS and biofilms) that helped to colonize the bacteria to the plant roots and soil particles that ultimately encouraged the more access to nutrients and protection of plant roots from toxins in soil ecosystem. © 2021 Friends Science Publishers
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Haas-Neill, Sandor, and Paul Forsythe. "A Budding Relationship: Bacterial Extracellular Vesicles in the Microbiota-Gut-Brain Axis." International Journal of Molecular Sciences 21, no. 23 (November 24, 2020): 8899. http://dx.doi.org/10.3390/ijms21238899.
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The discovery of the microbiota-gut-brain axis has revolutionized our understanding of systemic influences on brain function and may lead to novel therapeutic approaches to neurodevelopmental and mood disorders. A parallel revolution has occurred in the field of intercellular communication, with the realization that endosomes, and other extracellular vesicles, rival the endocrine system as regulators of distant tissues. These two paradigms shifting developments come together in recent observations that bacterial membrane vesicles contribute to inter-kingdom signaling and may be an integral component of gut microbe communication with the brain. In this short review we address the current understanding of the biogenesis of bacterial membrane vesicles and the roles they play in the survival of microbes and in intra and inter-kingdom communication. We identify recent observations indicating that bacterial membrane vesicles, particularly those derived from probiotic organisms, regulate brain function. We discuss mechanisms by which bacterial membrane vesicles may influence the brain including interaction with the peripheral nervous system, and modulation of immune activity. We also review evidence suggesting that, unlike the parent organism, gut bacteria derived membrane vesicles are able to deliver cargo, including neurotransmitters, directly to the central nervous system and may thus constitute key components of the microbiota-gut-brain axis.
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Lacoste, Arnaud, Fabienne Jalabert, Shelagh K. Malham, Anne Cueff, and Serge A. Poulet. "Stress and Stress-Induced Neuroendocrine Changes Increase the Susceptibility of Juvenile Oysters (Crassostrea gigas) to Vibrio splendidus." Applied and Environmental Microbiology 67, no. 5 (May 1, 2001): 2304–9. http://dx.doi.org/10.1128/aem.67.5.2304-2309.2001.
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ABSTRACT Oysters are permanently exposed to various microbes, and their defense system is continuously solicited to prevent accumulation of invading and pathogenic organisms. Therefore, impairment of the animal's defense system usually results in mass mortalities in cultured oyster stocks or increased bacterial loads in food products intended for human consumption. In the present study, experiments were conducted to examine the effects of stress on the juvenile oyster's resistance to the oyster pathogen Vibrio splendidus. Oysters (Crassostrea gigas) were challenged with a low dose of a pathogenic V. splendidus strain and subjected to a mechanical stress 3 days later. Both mortality andV. splendidus loads increased in stressed oysters, whereas they remained low in unstressed animals. Injection of noradrenaline or adrenocorticotropic hormone, two key components of the oyster neuroendocrine stress response system, also caused higher mortality and increased accumulation of V. splendidus in challenged oysters. These results suggest that the physiological changes imposed by stress, or stress hormones, influenced host-pathogen interactions in oysters and increased juvenile C. gigasvulnerability to Vibrio splendidus.
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Shurin, Jonathan B., Jessica L. Clasen, Hamish S. Greig, Pavel Kratina, and Patrick L. Thompson. "Warming shifts top-down and bottom-up control of pond food web structure and function." Philosophical Transactions of the Royal Society B: Biological Sciences 367, no. 1605 (November 5, 2012): 3008–17. http://dx.doi.org/10.1098/rstb.2012.0243.
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The effects of global and local environmental changes are transmitted through networks of interacting organisms to shape the structure of communities and the dynamics of ecosystems. We tested the impact of elevated temperature on the top-down and bottom-up forces structuring experimental freshwater pond food webs in western Canada over 16 months. Experimental warming was crossed with treatments manipulating the presence of planktivorous fish and eutrophication through enhanced nutrient supply. We found that higher temperatures produced top-heavy food webs with lower biomass of benthic and pelagic producers, equivalent biomass of zooplankton, zoobenthos and pelagic bacteria, and more pelagic viruses. Eutrophication increased the biomass of all organisms studied, while fish had cascading positive effects on periphyton, phytoplankton and bacteria, and reduced biomass of invertebrates. Surprisingly, virus biomass was reduced in the presence of fish, suggesting the possibility for complex mechanisms of top-down control of the lytic cycle. Warming reduced the effects of eutrophication on periphyton, and magnified the already strong effects of fish on phytoplankton and bacteria. Warming, fish and nutrients all increased whole-system rates of net production despite their distinct impacts on the distribution of biomass between producers and consumers, plankton and benthos, and microbes and macrobes. Our results indicate that warming exerts a host of indirect effects on aquatic food webs mediated through shifts in the magnitudes of top-down and bottom-up forcing.
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Usyskin-Tonne, Alla, Yitzhak Hadar, and Dror Minz. "Spike Formation Is a Turning Point Determining Wheat Root Microbiome Abundance, Structures and Functions." International Journal of Molecular Sciences 22, no. 21 (November 4, 2021): 11948. http://dx.doi.org/10.3390/ijms222111948.
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Root selection of their associated microbiome composition and activities is determined by the plant’s developmental stage and distance from the root. Total gene abundance, structure and functions of root-associated and rhizospheric microbiomes were studied throughout wheat growth season under field conditions. On the root surface, abundance of the well-known wheat colonizers Proteobacteria and Actinobacteria decreased and increased, respectively, during spike formation, whereas abundance of Bacteroidetes was independent of spike formation. Metagenomic analysis combined with functional co-occurrence networks revealed a significant impact of plant developmental stage on its microbiome during the transition from vegetative growth to spike formation. For example, gene functions related to biofilm and sensorial movement, antibiotic production and resistance and carbons and amino acids and their transporters. Genes associated with these functions were also in higher abundance in root vs. the rhizosphere microbiome. We propose that abundance of transporter-encoding genes related to carbon and amino acid, may mirror the availability and utilization of root exudates. Genes related to antibiotic resistance mechanisms were abundant during vegetative growth, while after spike formation, genes related to the biosynthesis of various antibiotics were enriched. This observation suggests that during root colonization and biofilm formation, bacteria cope with competitor’s antibiotics, whereas in the mature biofilm stage, they invest in inhibiting new colonizers. Additionally, there is higher abundance of genes related to denitrification in rhizosphere compared to root-associated microbiome during wheat growth, possibly due to competition with the plant over nitrogen in the root vicinity. We demonstrated functional and phylogenetic division in wheat root zone microbiome in both time and space: pre- and post-spike formation, and root-associated vs. rhizospheric niches. These findings shed light on the dynamics of plant–microbe and microbe–microbe interactions in the developing root zone.
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Gerna, Davide, Thomas Roach, Birgit Mitter, Wolfgang Stöggl, and Ilse Kranner. "Hydrogen Peroxide Metabolism in Interkingdom Interaction Between Bacteria and Wheat Seeds and Seedlings." Molecular Plant-Microbe Interactions® 33, no. 2 (February 2020): 336–48. http://dx.doi.org/10.1094/mpmi-09-19-0248-r.
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In endophytes, the abundance of genes coding for enzymes processing reactive oxygen species (ROS), including hydrogen peroxide (H2O2), argues for a crucial role of ROS metabolism in plant-microbe interaction for plant colonization. Here, we studied H2O2 metabolism of bread wheat (Triticum aestivum L.) seeds and their microbiota during germination and early seedling growth, the most vulnerable stages in the plant life cycle. Treatment with hot steam diminished the seed microbiota, and these seeds produced less extracellular H2O2 than untreated seeds. Using a culture-dependent approach, Pantoea and Pseudomonas genera were the most abundant epiphytes of dry untreated seeds. Incubating intact seedlings from hot steam–treated seeds with Pantoea strains triggered H2O2 production, whereas Pseudomonas strains dampened H2O2 levels, attributable to higher catalase activities. The genus Pantoea was much less represented among seedling endophytes than genus Pseudomonas, with other endophytic genera, including Bacillus and Paenibacillus, also possessing high catalase activities. Overall, our results show that certain bacteria of the seed microbiota are able to modulate the extracellular redox environment during germination and early seedling growth, and high catalase activity is proposed as a key trait of seed endophytes.
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Sharma, Manvi, Dhriti Singh, Harshita B. Saksena, Mohan Sharma, Archna Tiwari, Prakhar Awasthi, Halidev Krishna Botta, Brihaspati Narayan Shukla, and Ashverya Laxmi. "Understanding the Intricate Web of Phytohormone Signalling in Modulating Root System Architecture." International Journal of Molecular Sciences 22, no. 11 (May 24, 2021): 5508. http://dx.doi.org/10.3390/ijms22115508.
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Root system architecture (RSA) is an important developmental and agronomic trait that is regulated by various physical factors such as nutrients, water, microbes, gravity, and soil compaction as well as hormone-mediated pathways. Phytohormones act as internal mediators between soil and RSA to influence various events of root development, starting from organogenesis to the formation of higher order lateral roots (LRs) through diverse mechanisms. Apart from interaction with the external cues, root development also relies on the complex web of interaction among phytohormones to exhibit synergistic or antagonistic effects to improve crop performance. However, there are considerable gaps in understanding the interaction of these hormonal networks during various aspects of root development. In this review, we elucidate the role of different hormones to modulate a common phenotypic output, such as RSA in Arabidopsis and crop plants, and discuss future perspectives to channel vast information on root development to modulate RSA components.
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Trias, Rosalia, Arantzazu García-Lledó, Noemí Sánchez, José Luis López-Jurado, Sara Hallin, and Lluís Bañeras. "Abundance and Composition of Epiphytic Bacterial and Archaeal Ammonia Oxidizers of Marine Red and Brown Macroalgae." Applied and Environmental Microbiology 78, no. 2 (November 11, 2011): 318–25. http://dx.doi.org/10.1128/aem.05904-11.
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ABSTRACTAmmonia-oxidizing bacteria (AOB) and archaea (AOA) are important for nitrogen cycling in marine ecosystems. Little is known about the diversity and abundance of these organisms on the surface of marine macroalgae, despite the algae's potential importance to create surfaces and local oxygen-rich environments supporting ammonia oxidation at depths with low dissolved oxygen levels. We determined the abundance and composition of the epiphytic bacterial and archaeal ammonia-oxidizing communities on three species of macroalgae,Osmundaria volubilis,Phyllophora crispa, andLaminaria rodriguezii, from the Balearic Islands (western Mediterranean Sea). Quantitative PCR of bacterial and archaeal 16S rRNA andamoAgenes was performed. In contrast to what has been shown for most other marine environments, the macroalgae's surfaces were dominated by bacterialamoAgenes rather than those from the archaeal counterpart. On the basis of the sequences retrieved from AOB and AOAamoAgene clone libraries from each algal species, the bacterial ammonia-oxidizing communities were related toNitrosospiraspp. and toNitrosomonas europaeaand only 6 out of 15 operational taxonomic units (OTUs) were specific for the host species. Conversely, the AOA diversity was higher (43 OTUs) and algal species specific, with 17 OTUs specific forL. rodriguezii, 3 forO. volubilis, and 9 forP. crispa. Altogether, the results suggest that marine macroalgae may exert an ecological niche for AOB in marine environments, potentially through specific microbe-host interactions.
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Liu, Juan, Xiangwei He, Jingya Sun, and Yuchao Ma. "A Degeneration Gradient of Poplar Trees Contributes to the Taxonomic, Functional, and Resistome Diversity of Bacterial Communities in Rhizosphere Soils." International Journal of Molecular Sciences 22, no. 7 (March 26, 2021): 3438. http://dx.doi.org/10.3390/ijms22073438.
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Bacterial communities associated with roots influence the health and nutrition of the host plant. However, the microbiome discrepancy are not well understood under different healthy conditions. Here, we tested the hypothesis that rhizosphere soil microbial diversity and function varies along a degeneration gradient of poplar, with a focus on plant growth promoting bacteria (PGPB) and antibiotic resistance genes. Comprehensive metagenomic analysis including taxonomic investigation, functional detection, and ARG (antibiotics resistance genes) annotation revealed that available potassium (AK) was correlated with microbial diversity and function. We proposed several microbes, Bradyrhizobium, Sphingomonas, Mesorhizobium, Nocardioides, Variovorax, Gemmatimonadetes, Rhizobacter, Pedosphaera, Candidatus Solibacter, Acidobacterium, and Phenylobacterium, as candidates to reflect the soil fertility and the plant health. The highest abundance of multidrug resistance genes and the four mainly microbial resistance mechanisms (antibiotic efflux, antibiotic target protection, antibiotic target alteration, and antibiotic target replacement) in healthy poplar rhizosphere, corroborated the relationship between soil fertility and microbial activity. This result suggested that healthy rhizosphere soil harbored microbes with a higher capacity and had more complex microbial interaction network to promote plant growing and reduce intracellular levels of antibiotics. Our findings suggested a correlation between the plant degeneration gradient and bacterial communities, and provided insight into the role of high-turnover microbial communities as well as potential PGPB as real-time indicators of forestry soil quality, and demonstrated the inner interaction contributed by the bacterial communities.
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Koukounaras, Athanasios. "Advanced Greenhouse Horticulture: New Technologies and Cultivation Practices." Horticulturae 7, no. 1 (December 24, 2020): 1. http://dx.doi.org/10.3390/horticulturae7010001.
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Greenhouse horticulture is one of the most intensive agricultural systems, with the advantages of environmental parameter control (temperature, light, etc.), higher efficiency of resource utilization (water, fertilizers, etc.) and the use of advanced technologies (hydroponics, automation, etc.) for higher productivity, earliness, stability of production and better quality. On the other hand, climate change and the application of high inputs without suitable management could have negative impacts on the expansion of the greenhouse horticulture sector. This special issue gathers twelve papers: three reviews and nine of original research. There is one review that focuses on irrigation of greenhouse crops, while a second surveys the effects of biochar on container substrate properties and plant growth. A third review examines the impact of light quality on plant–microbe interactions, especially non-phototrophic organisms. The research papers report both the use of new technologies as well as advanced cultivation practices. In particular, new technologies are presented such as dye-sensitized solar cells for the glass cover of a greenhouse, automation for water and nitrogen deficit stress detection in soilless tomato crops based on spectral indices, light-emitting diode (LED) lighting and gibberellic acid supplementation on potted ornamentals, the integration of brewery wastewater treatment through anaerobic digestion with substrate-based soilless agriculture, and application of diatomaceous earth as a silica supplement on potted ornamentals. Research studies about cultivation practices are presented comparing different systems (organic-conventional, aeroponic-nutrient film technique (NFT)-substrate culture), quantitative criteria for determining the quality of grafted seedlings, and of wild species as alternative crops for cultivation.
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Yang, Mingming, Dmitri V. Mavrodi, Olga V. Mavrodi, Linda S. Thomashow, and David M. Weller. "Exploring the Pathogenicity of Pseudomonas brassicacearum Q8r1-96 and Other Strains of the Pseudomonas fluorescens Complex on Tomato." Plant Disease 104, no. 4 (April 2020): 1026–31. http://dx.doi.org/10.1094/pdis-09-19-1989-re.
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Pseudomonas brassicacearum and related species of the P. fluorescens complex have long been studied as biocontrol and growth-promoting rhizobacteria involved in suppression of soilborne pathogens. We report here that P. brassicacearum Q8r1-96 and other 2,4-diacetylphloroglucinol (DAPG)-producing fluorescent pseudomonads involved in take-all decline of wheat in the Pacific Northwest of the United States can also be pathogenic to other plant hosts. Strain Q8r1-96 caused necrosis when injected into tomato stems and immature tomato fruits, either attached or removed from the plant, but lesion development was dose dependent, with a minimum of 106 CFU ml−1 required to cause visible tissue damage. We explored the relative contribution of several known plant-microbe interaction traits to the pathogenicity of strain Q8r1-96. Type III secretion system (T3SS) mutants of Q8r1-96, injected at a concentration of 108 CFU ml−1, were significantly less virulent, but not consistently, as compared with the wild-type strain. However, a DAPG-deficient phlD mutant of Q8r1-96 was significantly and consistently less virulent as compared with the wild type. Strain Q8r1-96acc, engineered to over express ACC deaminase, caused a similar amount of necrosis as the wild type. Cell-free culture filtrates of strain Q8r1-96 and pure DAPG also cause necrosis in tomato fruits. Our results suggest that DAPG plays a significant role in the ability of Q8r1-96 to cause necrosis of tomato tissue, but other factors also contribute to the pathogenic properties of this organism.
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Karlsson, Elin, Cristina Paissoni, Amanda M. Erkelens, Zeinab A. Tehranizadeh, Frieda A. Sorgenfrei, Eva Andersson, Weihua Ye, Carlo Camilloni, and Per Jemth. "Mapping the transition state for a binding reaction between ancient intrinsically disordered proteins." Journal of Biological Chemistry 295, no. 51 (October 16, 2020): 17698–712. http://dx.doi.org/10.1074/jbc.ra120.015645.
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Intrinsically disordered protein domains often have multiple binding partners. It is plausible that the strength of pairing with specific partners evolves from an initial low affinity to a higher affinity. However, little is known about the molecular changes in the binding mechanism that would facilitate such a transition. We previously showed that the interaction between two intrinsically disordered domains, NCBD and CID, likely emerged in an ancestral deuterostome organism as a low-affinity interaction that subsequently evolved into a higher-affinity interaction before the radiation of modern vertebrate groups. Here we map native contacts in the transition states of the low-affinity ancestral and high-affinity human NCBD/CID interactions. We show that the coupled binding and folding mechanism is overall similar but with a higher degree of native hydrophobic contact formation in the transition state of the ancestral complex and more heterogeneous transient interactions, including electrostatic pairings, and an increased disorder for the human complex. Adaptation to new binding partners may be facilitated by this ability to exploit multiple alternative transient interactions while retaining the overall binding and folding pathway.
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Russell, David G., Sheila Sturgill-Koszycki, Tambryn Vanheyningen, Helen Collins, and Ulrich E. Schaible. "Why intracellular parasitism need not be a degrading experience for Mycobacterium." Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 352, no. 1359 (September 29, 1997): 1303–10. http://dx.doi.org/10.1098/rstb.1997.0114.
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The success of mycobacteria as pathogens hinges on their ability to infect and persist within the macrophages of their host. However, activation of host macrophages by cytokines from a productive cellular immune response can stimulate the cells to kill their resident pathogens. This suggests that the interaction between host cell and microbe is in delicate balance, which can be tipped in favour of either organism. Biochemical analysis of mycobacterial vacuoles has shown them to be integral to the host cell's recycling endosomal system. As such they show limited acidification and hydrolytic activity despite possession of known lysosomal constituents such as cathepsins D, B and L, and LAMP 1. Even in established infections, they remain dynamic compartments accessible to several plasmalemma–derived constituents. Once the macrophage has been activated by IFN–γ and TNF–α the vacuoles coalesce and acidify. This marks a distinct alteration in vacuole physiology and leads to stasis and death of the mycobacteria. Mycobacteria have developed several strategies to avoid this outcome. Most notably, live bacilli induce sustained release of IL–6 from infected macrophages. IL–6 blocks the ability of both polyclonal primary T cells and T–cell hybridomas to respond to appropriate stimuli. Such an activity could render the centers of infection foci, such as granulomas, anergic and thus avoid release of macrophage–activating cytokines. This paper discusses both the mechanisms by which mycobacteria try to ensure their success as intracellular pathogens and the relevance of these strategies to the overall understanding of mycobacterial diseases.
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Heisenberg, Martin. "Mind from Matter? – Via Brain and Behavior." Neuroforum 24, no. 2 (May 25, 2018): A95—A100. http://dx.doi.org/10.1515/nf-2018-a002.
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Abstract How did the process of Darwinian evolution lead from dead matter to the human mind? Of this long, complicated process the present essay selects and discusses just one step, that from animal behavior to animal mind. The process of living has two aspects, the maintenance of the process in the organism and the interaction of the organism with the world. In animals the latter is organized as behavior. Behavior evolves, as it serves the fitness of the animal. The brain evolves because it improves the behavior in terms of the animal’s fitness. Given the richness of the world and the openness of the future, the organization of behavior can be indirect and most intricate. The animal mind can be understood as behavioral organization at a higher level, as metaorganization. This concept is documented by behavioral studies in a particular animal, the fly Drosophila.
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Iesanu, Mara Ioana, Carmen Denise Mihaela Zahiu, Ioana-Alexandra Dogaru, Diana Maria Chitimus, Gratiela Gradisteanu Pircalabioru, Suzana Elena Voiculescu, Sebastian Isac, et al. "Melatonin–Microbiome Two-Sided Interaction in Dysbiosis-Associated Conditions." Antioxidants 11, no. 11 (November 14, 2022): 2244. http://dx.doi.org/10.3390/antiox11112244.
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Melatonin is a pineal indolamine, allegedly known as a circadian rhythm regulator, and an antioxidative and immunomodulatory molecule. In both experimental and clinical trials, melatonin has been shown to have positive effects in various pathologies, as a modulator of important biochemical pathways including inflammation, oxidative stress, cell injury, apoptosis, and energy metabolism. The gut represents one of melatonin’s most abundant extra pineal sources, with a 400-times-higher concentration than the pineal gland. The importance of the gut microbial community—namely, the gut microbiota, in multiple critical functions of the organism— has been extensively studied throughout time, and its imbalance has been associated with a variety of human pathologies. Recent studies highlight a possible gut microbiota-modulating role of melatonin, with possible implications for the treatment of these pathologies. Consequently, melatonin might prove to be a valuable and versatile therapeutic agent, as it is well known to elicit positive functions on the microbiota in many dysbiosis-associated conditions, such as inflammatory bowel disease, chronodisruption-induced dysbiosis, obesity, and neuropsychiatric disorders. This review intends to lay the basis for a deeper comprehension of melatonin, gut microbiota, and host-health subtle interactions.
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Schulze-Makuch, Dirk. "The Naked Mole-Rat: An Unusual Organism with an Unexpected Latent Potential for Increased Intelligence?" Life 9, no. 3 (September 16, 2019): 76. http://dx.doi.org/10.3390/life9030076.
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Naked mole-rats are eusocial, hairless mammals that are uniquely adapted to their harsh, low-oxygen subsurface habitat. Although their encephalization quotient, a controversial marker of intelligence, is low, they exhibit many features considered tell-tale signs of highly intelligent species on our planet including longevity, plasticity, social cohesion and interaction, rudimentary language, sustainable farming abilities, and maintaining sanitary conditions in their self-built complex housing structures. It is difficult to envision how naked mole-rats would reach even higher levels of intelligence in their natural sensory-challenged habitat, but such an evolutionary path cannot be excluded if they would expand their range onto the earth’s surface.
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Dworzański, Tomasz, Rafał Fornal, Łukasz Koźba, Krzysztof Celiński, and Ewa Dworzańska. "The role of intestinal microbiota in irritable bowel syndrome." Postępy Higieny i Medycyny Doświadczalnej 72 (April 9, 2018): 215–26. http://dx.doi.org/10.5604/01.3001.0011.7375.
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In recent years, impressive advances in the knowledge about a vast number of microbes living in the human body and interactions between the microbiota and the human body have been observed. All micro-organisms that live in the human body consist of around 10 ^ 14 cells. The number of microbial cells colonizing the human body is ten times higher than the number of its own cells and the weight of all micro-organisms is about 2-2.5 kg. The number of bacterial genes is 50-100 times greater than the number of genes in the human body. Nowadays, the human microbiota is often regarded as a “newly discovered organ” or even as a “supergenome”. The results of many studies have revealed that disruption of the bowel microecosystem may affect the development of irritable bowel syndrome (IBS) symptoms. Therefore, manipulation of the gut microflora was hoped to be a new tool in the treatment of this disease. Various methods (probiotics, prebiotics, antibiotic therapy, transplantation of faecal flora) have been used to modify the intestinal microbiota by supporting the expansion of bacteria considered beneficial and reducing the number of those regarded as harmful, thus alleviating the IBS symptoms. There is much evidence in the literature to suggest that the intestinal microbiota and the gut-intestinal axis are important factors in the pathogenesis of IBS. Moreover, the literature findings have demonstrated beneficial effects of modifying the intestinal flora composition in alleviating IBS symptoms. Although the pathophysiology of IBS and the role of the intestinal microflora and gut-intestinal axis in it are well known, many issues are still to be elucidated. Further research into the bacteria identified in stool and colon mucosa of healthy individuals should provide more information on restoration of intestinal homeostasis in IBS patients.
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Nusantara, Abimanyu Dipo, Yudhy Harini Bertham, Ahmad Junedi, Hesti Pujiwati, and Hartal Hartal. "PEMANFAATAN MIKROBA UNTUK MENINGKATKAN PERTUMBUHAN DAN HASIL KEDELAI DI TANAH PESISIR." Jurnal Ilmu-Ilmu Pertanian Indonesia 21, no. 1 (June 26, 2019): 37–43. http://dx.doi.org/10.31186/jipi.21.1.37-43.
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[UTILIZATION OF MICROBE TO INCREASE GROWTH AND YIELDS OF SOYBEAN IN COASTAL LAND. This study aims to obtain the right combination of varieties and biofertilizers to increase soybean productivity on Bengkulu coastal land. The research was conducted from March to July 2017, located in Beringin Raya Village, Muara Bangkahulu Sub-District, Bengkulu. The study was conducted with a split-plot design which was repeated three times. The main plot is two soybean varieties (Grobogan and Wilis). The subplots are two types of biological fertilizers, arbuscular mycorrhizal fungi, and phosphate solvent fungi. The results showed that the results of the seed weight of the Grobogan variety (equivalent to 3.38 tons/ha) were significantly higher than the Wilis variety (equivalent to 2.72 tons/ha). However, the Wilis variety showed an increase in seed weight (equivalent to 1.12 tons/ha) higher than the Grobogan variety (equivalent to 0.61 tons/ha) according to the description of each variety. The combination of arbuscular mycorrhizal fungi and phosphate solvent fungi showed superior performance than arbuscular mycorrhizal fungi fertilizer or phosphate solvent fungi. The interaction of Grobogan varieties with a combination of arbuscular mycorrhizal fungi and phosphate solvent fungi produced the highest seed weight (equivalent to 3.52 tons/ha) which was statistically similar to the interaction of Grobogan varieties and arbuscular mycorrhizal fungi (equivalent to 3.45 tons/ha). The economics of resources using arbuscular mycorrhizal fungi are not required to be combined with phosphate solvent fungi.
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Konstantinov, Kosana, Snezana Drinic-Mladenovic, and Goran Drinic. "Biotechnology: reality or dream." Genetika 34, no. 2-3 (2002): 101–13. http://dx.doi.org/10.2298/gensr0203101k.
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The development of molecular biology and molecular genetics, especially of the recombinant DNA technology enabled improvement of experimental methods that provide manipulation within a cell-free system, such as cell and tissue cultures. Such methods resulted in the development of different new technologies with specific properties in relation to the conventional definitions. According to PERSLEY and lantin (2000) the following components are essential for the contemporary biotechnology: (i) genomics - a molecular characterization of all genes and gene products of an organism (ii) bioinformatics - the assembly of data from genomic analysis into accessible forms; (iii) transformation - the introduction of genes controlling a trait of interest into a genome of a desired organism (micro organisms, plants, animal systems). By the application of cotemporary biotechnology new methods in the field of diagnostic are developed such as rapid and more accurate identification of the presence and absence of genes in the genome of the organism of interest (identification of pathogens prenatal diagnostics, molecular markers assisted breeding for plants, etc). The traits of an organism are determined by its genetic material, i.e. by a molecule of deoxyribonucleic acid (DNA). watson and crick (1953) were the first scientists to describe the structure of DNA as a double-stranded helix. Higher organisms contain a set of linear DNA molecules - chromosomes and a full set of chromosomes of an organism is a genome. Each genome is divided into a series of functional units, i.e. genes. The traits of an organism depend on genes, but their expression depends not only on genes but also on many other factors, including whether a gene, controlling the trait, expresses, specific cells in which it expresses and specially the mode by which the gene and its product interact with the environment. A special aspect within the application of biotechnology occurs as an interaction of a foreign gene with a genome of an integrated organism. Also application of biotechnology provides transfer of one or several favorable genes from any evolutionary category into other category of an organism and in such a way it is possible to develop genetically modified organisms (GMO) having expressed desired, target traits. A survey of the application of biotechnology in the world and our country is presented in this paper.
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Zhizhin, Gennadiy Vladimirovich. "Methylated Polytope of Hereditary Information." International Journal of Applied Research on Public Health Management 6, no. 2 (July 2021): 49–60. http://dx.doi.org/10.4018/ijarphm.2021070104.
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The geometric features of nucleic acids during methylation of their nitrogenous bases, which is typical for viral nucleic acids in infectious diseases, were studied. It was found that methylation of viral nucleic acids leads to the transition of their nitrogenous bases into the space of higher dimension and sharply increases (more than 2000 times) the intensity of information processes in the field of interaction of nucleic acids (in the polytopic of hereditary information). The activity of methylated viral nucleic acids can be countered by activation (i.e., a fairly high degree of methylation, nucleic acids of the organism).
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Nawroth, J. C., K. E. Feitl, S. P. Colin, J. H. Costello, and J. O. Dabiri. "Phenotypic plasticity in juvenile jellyfish medusae facilitates effective animal–fluid interaction." Biology Letters 6, no. 3 (March 24, 2010): 389–93. http://dx.doi.org/10.1098/rsbl.2010.0068.
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Locomotion and feeding in marine animals are intimately linked to the flow dynamics created by specialized body parts. This interaction is of particular importance during ontogeny, when changes in behaviour and scale challenge the organism with shifts in fluid regimes and altered functionality. Previous studies have indicated that Scyphozoan jellyfish ontogeny accommodates the changes in fluid dynamics associated with increasing body dimensions and velocities during development. However, in addition to scale and behaviour that—to a certain degree—underlie the control of the animal, flow dynamics are also dependent on external factors such as temperature. Here, we show phenotypic plasticity in juvenile Aurelia aurita medusae, where morphogenesis is adapted to altered fluid regimes imposed by changes in ambient temperature. In particular, differential proportional growth was found to compensate for temperature-dependent changes in viscous effects, enabling the animal to use adhering water boundary layers as ‘paddles’—and thus economize tissue—at low temperatures, while switching to tissue-dominated propulsion at higher temperatures where the boundary layer thickness is insufficient to serve for paddling. This effect was predicted by a model of animal–fluid interaction and confirmed empirically by flow-field visualization and assays of propulsion efficiency.
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Whistler, Cheryl A., and Edward G. Ruby. "GacA Regulates Symbiotic Colonization Traits ofVibrio fischeri and Facilitates a Beneficial Association withan AnimalHost." Journal of Bacteriology 185, no. 24 (December 15, 2003): 7202–12. http://dx.doi.org/10.1128/jb.185.24.7202-7212.2003.
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ABSTRACT The GacS/GacA two-component system regulates the expression of bacterial traits during host association. Although the importance of GacS/GacA as a regulator of virulence is well established, its role in benign associations is not clear, as mutations in either the gacS or gacA gene have little impact on the success of colonization in nonpathogenic associations studied thus far. Using as a model the symbiotic association of the bioluminescent marine bacterium Vibrio fischeri with its animal host, the Hawaiian bobtail squid, Euprymna scolopes, we investigated the role of GacA in this beneficial animal-microbe interaction. When grown in culture, gacA mutants were defective in several traits important for symbiosis, including luminescence, growth in defined media, growth yield, siderophore activity, and motility. However, gacA mutants were not deficient in production of acylated homoserine lactone signals or catalase activity. The ability of the gacA mutants to initiate squid colonization was impaired but not abolished, and they reached lower-than-wild-type population densities within the host light organ. In contrast to their dark phenotype in culture, gacA mutants that reached population densities above the luminescence detection limit had normal levels of luminescence per bacterial cell in squid light organs, indicating that GacA is not required for light production within the host. The gacA mutants were impaired at competitive colonization and could only successfully cocolonize squid light organs when present in the seawater at higher inoculum densities than wild-type bacteria. Although severely impaired during colonization initiation, gacA mutants were not displaced by the wild-type strain in light organs that were colonized with both strains. This study establishes the role of GacA as a regulator of a beneficial animal-microbe association and indicates that GacA regulates utilization of growth substrates as well as other colonization traits.
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Alexiev, Alexandra, Melissa Y. Chen, and Valerie J. McKenzie. "Identifying fungal-host associations in an amphibian host system." PLOS ONE 16, no. 8 (August 19, 2021): e0256328. http://dx.doi.org/10.1371/journal.pone.0256328.
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Host-associated microbes can interact with macro-organisms in a number of ways that affect host health. Few studies of host-associated microbiomes, however, focus on fungi. In addition, it is difficult to discern whether a fungal organism found in or on an ectotherm host is associating with it in a durable, symbiotic interaction versus a transient one, and to what extent the habitat and host share microbes. We seek to identify these host-microbe interactions on an amphibian, the Colorado boreal toad (Anaxyrus boreas boreas). We sequenced the ITS1 region of the fungal community on the skin of wild toads (n = 124) from four sites in the Colorado Rocky Mountains, across its physiologically dynamic developmental life stages. We also sampled the common habitats used by boreal toads: water from their natal wetland and aquatic pond sediment. We then examined diversity patterns within different life stages, between host and habitat, and identified fungal taxa that could be putatively host-associated with toads by using an indicator species analysis on toad versus environmental samples. Host and habitat were strikingly similar, with the exception of toad eggs. Post-hatching toad life stages were distinct in their various fungal diversity measures. We identified eight fungal taxa that were significantly associated with eggs, but no other fungal taxa were associated with other toad life stages compared with their environmental habitat. This suggests that although pre- and post-metamorphic toad life stages differ from each other, the habitat and host fungal communities are so similar that identifying obligate host symbionts is difficult with the techniques used here. This approach does, however, leverage sequence data from host and habitat samples to predict which microbial taxa are host-associated versus transient microbes, thereby condensing a large set of sequence data into a smaller list of potential targets for further consideration.
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Hurst, Gregory D. D. "Extended genomes: symbiosis and evolution." Interface Focus 7, no. 5 (August 18, 2017): 20170001. http://dx.doi.org/10.1098/rsfs.2017.0001.
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Many aspects of an individual's biology derive from its interaction with symbiotic microbes, which further define many aspects of the ecology and evolution of the host species. The centrality of microbes in the function of individual organisms has given rise to the concept of the holobiont—that an individual's biology is best understood as a composite of the ‘host organism’ and symbionts within. This concept has been further elaborated to posit the holobiont as a unit of selection. In this review, I critically examine whether it is useful to consider holobionts as a unit of selection. I argue that microbial heredity—the direct passage of microbes from parent to offspring—is a key factor determining the degree to which the holobiont can usefully be considered a level of selection. Where direct vertical transmission (VT) is common, microbes form part of extended genomes whose dynamics can be modelled with simple population genetics, but that nevertheless have subtle quantitative distinctions from the classic mutation/selection model for nuclear genes. Without direct VT, the correlation between microbial fitness and host individual fitness erodes, and microbe fitness becomes associated with host survival only (rather than reproduction). Furthermore, turnover of microbes within a host may lessen associations between microbial fitness with host survival, and in polymicrobial communities, microbial fitness may derive largely from the ability to outcompete other microbes, to avoid host immune clearance and to minimize mortality through phage infection. These competing selection pressures make holobiont fitness a very minor consideration in determining symbiont evolution. Nevertheless, the importance of non-heritable microbes in organismal function is undoubted—and as such the evolutionary and ecological processes giving rise to variation and evolution of the microbes within and between host individuals represent a key research area in biology.
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Proudfoot, A. E. I. "The biological relevance of chemokine–proteoglycan interactions." Biochemical Society Transactions 34, no. 3 (May 22, 2006): 422–26. http://dx.doi.org/10.1042/bst0340422.
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Chemokines exert their biological activity through high-affinity interactions with cell-surface receptors, thereby activating specific signalling pathways, and a second low-affinity interaction with proteoglycans. Proteoglycans consist of a protein core, to which GAG (glycosaminoglycan) chains are attached. The GAGs are long, linear, sulphated and highly charged heterogeneous polysaccharides that are expressed throughout the body in different forms depending on the developmental or pathological state of the organ/organism. Mechanistically, the GAG interaction is thought to facilitate the retention of chemokines on cell surfaces, thereby forming a high local concentration required for cell activation. Recently, we demonstrated that certain chemokines require interactions with GAGs for their in vivo function. Additionally we have shown that chemokines oligomerize on immobilized GAGs, and this ability to form higher order oligomers has also been shown to be essential for the activity of certain chemokines in vivo. We believe that interference with the chemokine–GAG interaction provides a novel anti-inflammatory strategy, exemplified by a variant of RANTES (regulated upon activation, normal T-cell expressed and secreted) that has abrogated GAG binding and oligomerization properties.
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Li, Xiang-Yi, Tim Lachnit, Sebastian Fraune, Thomas C. G. Bosch, Arne Traulsen, and Michael Sieber. "Temperate phages as self-replicating weapons in bacterial competition." Journal of The Royal Society Interface 14, no. 137 (December 2017): 20170563. http://dx.doi.org/10.1098/rsif.2017.0563.
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Microbial communities are accompanied by a diverse array of viruses. Through infections of abundant microbes, these viruses have the potential to mediate competition within the community, effectively weakening competitive interactions and promoting coexistence. This is of particular relevance for host-associated microbial communities, because the diversity of the microbiota has been linked to host health and functioning. Here, we study the interaction between two key members of the microbiota of the freshwater metazoan Hydra vulgaris . The two commensal bacteria Curvibacter sp. and Duganella sp. protect their host from fungal infections, but only if both of them are present. Coexistence of the two bacteria is thus beneficial for Hydra . Intriguingly, Duganella sp. appears to be the superior competitor in vitro due to its higher growth rate when both bacteria are grown separately, but in co-culture the outcome of competition depends on the relative initial abundances of the two species. The presence of an inducible prophage in the Curvibacter sp. genome, which is able to lytically infect Duganella sp., led us to hypothesize that the phage modulates the interaction between these two key members of the Hydra microbiota. Using a mathematical model, we show that the interplay of the lysogenic life cycle of the Curvibacter phage and the lytic life cycle on Duganella sp. can explain the observed complex competitive interaction between the two bacteria. Our results highlight the importance of taking lysogeny into account for understanding microbe–virus interactions and show the complex role phages can play in promoting coexistence of their bacterial hosts.