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Ayyappadasan, G., S. Rubavathi y V. Venkatraman. "Lichenized Bacteria: A Pioneer Source of Biomedical and Environmental Protection". International Journal of Research and Review 11, n.º 1 (29 de enero de 2024): 494–500. http://dx.doi.org/10.52403/ijrr.20240155.
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The review highlights the synthesis of secondary metabolites by symbiotic bacteria, emphasizing the importance of these compounds in various stages of symbiotic interactions. Recognizing the roles of natural products, such as complex polyketides and nonribosomal peptides, extends from partner recognition and invasion to establishing bacterial populations, providing nutrition, and contributing to chemical defense. Notably, the study focuses on unculturable symbionts, with cultivation-independent techniques playing a significant role in advancing research in this field. The notion is that bacterial symbionts, particularly in marine invertebrates like sponges, are likely the actual producers of numerous drug candidates found in these organisms. Sponges, recognized as a significant source of biologically active natural products, are often thought to harbor compounds originating from bacteria. Biofouling, the unwanted buildup of microorganisms on submerged structures and living marine organisms, presents economic challenges, including increased fuel consumption and metal corrosion. Diverse studies, spanning morphology, biochemistry, and molecular characteristics, highlight the complexity of biofouling. To address these issues and mitigate economic losses, there is a pressing need to identify effective natural antifouling agents capable of controlling the abundant biofouling bacteria in marine environments. Keywords: Antifouling, Symbionts, Lichen, Parmeloid
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Liang, Ting, Wenqiang Zhao, Yongping Kou, Jia Liu y Qing Liu. "Soil Microbial and Organic Carbon Legacies of Pre-Existing Plants Drive Pioneer Tree Growth during Subalpine Forest Succession". Forests 13, n.º 7 (15 de julio de 2022): 1110. http://dx.doi.org/10.3390/f13071110.
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Fast-growing pioneer tree species play a crucial role in triggering late successional development in forests. Experimental evidence of the soil legacy effects of pre-existing plants on pioneer tree performance is lacking. We explored the legacy effects of soils conditioned by early successional herbs (Poa poophagorum Bor and Potentilla fragarioides L.) and mid-successional shrubs (Rhododendron fortunei Lindl. and Enkianthus quinqueflorus Lour.) on late-successional ectomycorrhizal (ECM) pioneer tree (Betula platyphylla Sukaczev) seedling growth. The soils were analyzed for soil nutrient status and fungal and bacterial compositions using ITS and 16S rRNA gene sequencing. B. platyphylla seedlings produced higher biomass in soils conditioned by shrubs. Soil organic carbon (SOC) and bacterial and fungal legacies most impacted pioneer tree seedling growth. Additionally, the partial least squares path model revealed that soil nutrients, especially SOC, indirectly affected seedling biomass by their direct effects on the bacterial and fungal communities. The changes in bacterial community composition had a stronger effect on seedling biomass than those of fungi because bacteria with shorter turnover times are generally considered to be more efficient than fungi in enhancing nutrient availability. Our study integrates soil microbial and nutrient legacies to explain the potential mechanisms of pioneer tree regeneration.
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Scortichini, M., A. Belisario y E. Motta. "Bacterial Species in Relation to Forest Tree Decline". Arboriculture & Urban Forestry 17, n.º 9 (1 de septiembre de 1991): 246–49. http://dx.doi.org/10.48044/jauf.1991.057.
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Bacterial species colonize trees endophytically without causing apparent damage, but can act as facultative parasites by utilizing tissues altered by abioticfactors. Bacteria, especially anaerobic species, can cause wetwood perse and act as pioneer microorganisms that prepare substrates for decay fungi. Xylella fastidiosa, a xylem-limited bacterium, acts as a primary pathogen inciting leaf scorch and dieback in some trees. Bacterial penetration occurs via wounds in the aerial part of the plant or in the roots. Some bacteria can act as agents of ice formation (ice nucleation active bacteria) also promoting the entry of other organisms.
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Wächtershäuser, Günter. "From volcanic origins of chemoautotrophic life to Bacteria, Archaea and Eukarya". Philosophical Transactions of the Royal Society B: Biological Sciences 361, n.º 1474 (7 de septiembre de 2006): 1787–808. http://dx.doi.org/10.1098/rstb.2006.1904.
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The theory of a chemoautotrophic origin of life in a volcanic iron–sulphur world postulates a pioneer organism at sites of reducing volcanic exhalations. The pioneer organism is characterized by a composite structure with an inorganic substructure and an organic superstructure. Within the surfaces of the inorganic substructure iron, cobalt, nickel and other transition metal centres with sulphido, carbonyl and other ligands were catalytically active and promoted the growth of the organic superstructure through carbon fixation, driven by the reducing potential of the volcanic exhalations. This pioneer metabolism was reproductive by an autocatalytic feedback mechanism. Some organic products served as ligands for activating catalytic metal centres whence they arose. The unitary structure–function relationship of the pioneer organism later gave rise to two major strands of evolution: cellularization and emergence of the genetic machinery. This early phase of evolution ended with segregation of the domains Bacteria, Archaea and Eukarya from a rapidly evolving population of pre-cells. Thus, life started with an initial, direct, deterministic chemical mechanism of evolution giving rise to a later, indirect, stochastic, genetic mechanism of evolution and the upward evolution of life by increase of complexity is grounded ultimately in the synthetic redox chemistry of the pioneer organism.
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Doll-Nikutta, Katharina, Andreas Winkel, Ines Yang, Anna Josefine Grote, Nils Meier, Mosaieb Habib, Henning Menzel, Peter Behrens y Meike Stiesch. "Adhesion Forces of Oral Bacteria to Titanium and the Correlation with Biophysical Cellular Characteristics". Bioengineering 9, n.º 10 (17 de octubre de 2022): 567. http://dx.doi.org/10.3390/bioengineering9100567.
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Bacterial adhesion to dental implants is the onset for the development of pathological biofilms. Reliable characterization of this initial process is the basis towards the development of anti-biofilm strategies. In the present study, single-cell force spectroscopy (SCFS), by means of an atomic force microscope connected to a microfluidic pressure control system (FluidFM), was used to comparably measure adhesion forces of different oral bacteria within a similar experimental setup to the common implant material titanium. The bacteria selected belong to different ecological niches in oral biofilms: the commensal pioneers Streptococcus oralis and Actinomyces naeslundii; secondary colonizer Veillonella dispar; and the late colonizing pathogens Porphyromonas gingivalis as well as fimbriated and non-fimbriated Aggregatibacter actinomycetemcomitans. The results showed highest values for early colonizing pioneer species, strengthening the link between adhesion forces and bacteria’s role in oral biofilm development. Additionally, the correlation between biophysical cellular characteristics and SCFS results across species was analyzed. Here, distinct correlations between electrostatically driven maximum adhesion force, bacterial surface elasticity and surface charge as well as single-molecule attachment points, stretching capability and metabolic activity, could be identified. Therefore, this study provides a step towards the detailed understanding of oral bacteria initial adhesion and could support the development of infection-resistant implant materials in future.
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Li, Junmin, Zexin Jin y Qiping Gu. "Effect of plant species on the function and structure of the bacterial community in the rhizosphere of lead–zinc mine tailings in Zhejiang, China". Canadian Journal of Microbiology 57, n.º 7 (julio de 2011): 569–77. http://dx.doi.org/10.1139/w11-054.
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To uncover the role played by pioneer plants in the natural succession of vegetation on heavy-metal mine tailings, it is important to explore the sensitive indicator of rhizosphere microbial community performance. We investigated the structure and function of rhizosphere bacterial communities of five pioneer plants growing on lead–zinc mine tailings in Zhejiang, China. Compared with the control, all five pioneer plants differentially affected the structure and function of rhizosphere bacterial communities. The number of bacteria, the activity of β-glucosidase and urease, and species richness indices were the highest in the rhizosphere of Erigeron annuus . The carbon utilization ability and the functional diversity indices were the highest in the rhizosphere of Lysimachia clethroides . There was no significant relationship between the functional or structural diversity indices and the bioavailable heavy-metal content among each species. Clustering analysis and the nonmetric dimensional scaling biplot showed that the rhizosphere bacterial communities of the five pioneer plants were different from those of control, indicating that plant species might be the main driver of microbial community composition on mine tailings. Both L. clethroides and E. annuus might be appropriate candidates for phytoremediation of mine tailings for higher soil microbial community function and species richness in rhizosphere.
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Laukens, D. "ECCO Pioneer Award Functional assessment of the microbiome in persistent IBD-related psychological symptoms". Journal of Crohn's and Colitis 18, Supplement_1 (1 de enero de 2024): i2258. http://dx.doi.org/10.1093/ecco-jcc/jjad212.1421.
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Abstract Background and Aims It is well established that patients with inflammatory bowel disease (IBD) experience psychological comorbidities, and that these symptoms persist upon remission of the IBD in more than 50% of patients. The mechanisms underlying this clinical association are unknown, which hampers to objectify the problem and limits the possibilities to intelligently consider targeted treatments. We recently observed behavioral anomalies and neuroinflammation in a mouse model of extinguished chronic colitis, enabling the fundamental study of psychological symptoms in IBD. Fueled by technical evolutions to characterize translationally active bacteria at the single-cell level, their importance in colitis, and a proof-of-concept stool transplantation experiment, the purpose of this project is to determine if specific bacterial functions drive persistent neuroinflammation upon IBD remission. Methods First, a state-of-the-art flow-cytometry based method will be used to temporally map translationally active bacteria during the course of extinguished chronic colitis. Second, the same functional microbial analysis will be achieved in human fecal samples of IBD patients in remission before and after treatment for fatigue, and results will be compared with persistent bacterial changes found in mouse flora. Finally, causality of associated bacteria to induce neuroinflammation will be tested by transplantation studies of bacterial communities isolated from the previous tasks. Anticipated Impact This research may impact the field in the short-term by creating solid scientific awareness that psychological comorbidities are intrinsically linked with IBD remission, and by more specifically attributing a role for specific bacterial functions in these symptoms. In addition, the technique applied may open novel insights for the IBD microbiome community. In the medium-term, this project aims to shed light on the actual bacterial mechanisms that lead to neuroinflammation and behavioral anomalies, which in the long-term could help identify biomarkers for diagnostic purposes or microbiome-related targets to design rational therapeutics for patients with IBD suffering from psychological comorbidities.
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Apoorva, SM, A. Suchetha, DB Mundinamane, DP Bhopale, A. Bharwani y R. Prasad. "An Insight into the Role of Benefical Bacteria in Periodontal Pocket Recolonization: A Literature Review". Journal of Oral Health and Community Dentistry 8, n.º 1 (enero de 2014): 47–50. http://dx.doi.org/10.5005/johcd-8-1-47.
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ABSTRACT Microflora can be found in both caries-free and periodontitis-free people and caries-affected and periodontitis-affected people, and many clinical studies reveal that the portion of certain bacterial species such as Streptococcus mutans or Porphyromonas gingivalis, respectively, is increased in patients with caries or periodontitis. Therefore, it seems that the competition that results between beneficial bacteria and virulent bacteria leads to either a healthy or sick status of human beings. Competition between members of the dental microflora and there role in pocket recolonization is very complex and many antagonistic characteristics can be observed from competition for initial attachment on tooth surfaces or for later attachment to pioneer bacteria, competition from bacteriocins or hydrogen peroxide secreted and from facilitating the growth of some species which inhibit other species. To date only some of the details of these mechanisms are known. The present review will provide an overview on the prevalence of beneficial bacteria and the major mechanisms of oral bacterial interactions. Due to the large number of oral bacterial species, only the best characterized species are included in this review.
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Handayani, D. P., Sulastri, I. S. Bidara, S. Himawati, N. A. Saryanah y R. Reninta. "The Application of endophytic halotolerant bacteria in modulating the development of maize seedlings under salinity". IOP Conference Series: Earth and Environmental Science 1182, n.º 1 (1 de junio de 2023): 012042. http://dx.doi.org/10.1088/1755-1315/1182/1/012042.
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Abstract Salinity stress has negative effects on plants physiologically as well as lowering productivity. Application of microbial inoculant as seed treatment is one of the bio-techniques that have proved to be efficient in enhancing salinity resilience in agriculture, especially for seedling development. This study aims to determine the effect of inoculation of halotolerant bacteria consortium on the development of maize seedlings under saline stress. The experiment used four different bacterial consortia namely B5 (two species of phosphate solubilizing bacteria); B6 (phosphate solubilizing bacteria, and ACC deaminase producing bacteria); B7 (phosphate solubilizing bacteria and nitrogen-fixing bacteria) and B9 (phosphate solubilizing bacteria, ACC deaminase producing bacteria and nitrogen-fixing bacteria). The salinity stress was conducted by adding NaCl with a concentration of 0, 50, 100, and 150 mM to the Hoagland nutrient solution as a germination medium. The inoculation bacteria increased the root length, root number, shoot length, fresh weight, and chlorophyll content of Pioneer maize seedling up to 25% at salinity stress treatment 150 mM NaCl. The highest increase in seedlings growth parameters was observed on seedlings inoculated by B5, B7, and B9 under a salinity treatment of 150 mM.
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Lathifah, A. N., A. A. Asmara, F. A. N. Alfisyahr y F. B. Maziya. "Potency of Indigenous Bacteria of Mt. Merapi, Arthrobacter chlorophenolicus for Chromium (VI) Bioremediation". IOP Conference Series: Earth and Environmental Science 933, n.º 1 (1 de noviembre de 2021): 012011. http://dx.doi.org/10.1088/1755-1315/933/1/012011.
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Abstract Chromium (VI) in the production process, such as textile, tannery, and electroplating industry, produce hazardous waste when disposed of directly into the aquatic environment. Several chromium pollutions cases, not only in water but also in the aquatic organism, occurred in some regions in Indonesia. Various methods can reduce the Chromium (VI) waste. One of them is the biological method by employing such kinds of bacteria. Arthrobacter chlorophenolicus is a pioneer bacterium of Mt. Merapi, which can survive in the minimum conditions of the bacterial primary nutrients, carbon, and nitrogen. This study aims to investigate the ability of A. chlorophenolicus to remove Cr (VI) at various concentrations. The research was carried out by growing the A. chlorophenolicus into two nutrient media conditions, minimal and rich-nutrient media containing different concentrations of Cr (VI) (5, 10, 20 ppm) for eight days. The results showed that the A. chlorophenolicus were grown on both minimal and rich-nutrient media. The A. chlorophenolicus could reduce for about 80% of 10 and 20 ppm chromium in eight days. Our results indicate that A. chlorophenolicus, the pioneer bacteria of Mt. Merapi, has a grand promise for use in Cr (VI) remediation even under minimum nutrients conditions.
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Rincón-Molina, Clara Ivette, Esperanza Martínez-Romero, José Luis Aguirre-Noyola, Luis Alberto Manzano-Gómez, Adalberto Zenteno-Rojas, Marco Antonio Rogel, Francisco Alexander Rincón-Molina, Víctor Manuel Ruíz-Valdiviezo y Reiner Rincón-Rosales. "Bacterial Community with Plant Growth-Promoting Potential Associated to Pioneer Plants from an Active Mexican Volcanic Complex". Microorganisms 10, n.º 8 (4 de agosto de 2022): 1568. http://dx.doi.org/10.3390/microorganisms10081568.
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Microorganisms in extreme volcanic environments play an important role in the development of plants on newly exposed substrates. In this work, we studied the structure and diversity of a bacterial community associated to Andropogon glomeratus and Cheilanthes aemula at El Chichón volcano. The genetic diversity of the strains was revealed by genomic fingerprints and by 16S rDNA gene sequencing. Furthermore, a metagenomic analysis of the rhizosphere samples was carried out for pioneer plants growing inside and outside the volcano. Multifunctional biochemical tests and plant inoculation assays were evaluated to determine their potential as plant growth-promoting bacteria (PGPB). Through metagenomic analysis, a total of 33 bacterial phyla were identified from A. glomeratus and C. aemula rhizosphere samples collected inside the volcano, and outside the volcano 23 bacterial phyla were identified. For both rhizosphere samples, proteobacteria was the most abundant phylum. With a cultivable approach, 174 bacterial strains were isolated from the rhizosphere and tissue of plants growing outside the volcanic complex. Isolates were classified within the genera Acinetobacter, Arthrobacter, Bacillus, Burkholderia, Cupriavidus, Enterobacter, Klebsiella, Lysinibacillus, Pantoea, Pseudomonas, Serratia, Stenotrophomonas and Pandoraea. The evaluated strains were able to produce indole compounds, solubilize phosphate, synthesize siderophores, showed ACC deaminase and nitrogenase activity, and they had a positive effect on the growth and development of Capsicum chinense. The wide diversity of bacteria associated to pioneer plants at El Chichón volcano with PGPB qualities represent an alternative for the recovery of eroded environments, and they can be used efficiently as biofertilizers for agricultural crops growing under adverse conditions.
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Garland, Gavin D., Kiran R. Patil, Suzanne D. Turner y Anne E. Willis. "The Pioneer platform: A novel approach for selection of selective anti-cancer cytotoxic activity in bacteria through co-culturing with engineered human cells". PLOS ONE 18, n.º 6 (6 de junio de 2023): e0286741. http://dx.doi.org/10.1371/journal.pone.0286741.
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Most of the small-molecule drugs approved for the treatment of cancer over the past 40 years are based on natural compounds. Bacteria provide an extensive reservoir for the development of further anti-cancer therapeutics to meet the challenges posed by the diversity of these malignant diseases. While identifying cytotoxic compounds is often easy, achieving selective targeting of cancer cells is challenging. Here we describe a novel experimental approach (the Pioneer platform) for the identification and development of ‘pioneering’ bacterial variants that either show or are conduced to exhibit selective contact-independent anti-cancer cytotoxic activities. We engineered human cancer cells to secrete Colicin M that repress the growth of the bacterium Escherichia coli, while immortalised non-transformed cells were engineered to express Chloramphenicol Acetyltransferase capable of relieving the bacteriostatic effect of Chloramphenicol. Through co-culturing of E. coli with these two engineered human cell lines, we show bacterial outgrowth of DH5α E. coli is constrained by the combination of negative and positive selection pressures. This result supports the potential for this approach to screen or adaptively evolve ‘pioneering’ bacterial variants that can selectively eliminate the cancer cell population. Overall, the Pioneer platform demonstrates potential utility for drug discovery through multi-partner experimental evolution.
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Ertekin, Ibrahim. "Effects of commercial bacterial inoculants on fermentation and nutritive quality of wheat and annual legume mixed silages". Bangladesh Journal of Botany 52, n.º 3 (12 de octubre de 2023): 775–82. http://dx.doi.org/10.3329/bjb.v52i3.68896.
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In the present study fermentation quality, microbial populations and nutritive value of wheat and some cool season annual legume (forage pea, grass pea and vetch) mixed silages (25:75, 50:50 and 75:25) using various commercial bacterial inoculants (Pioneer 1188, Pioneer 11A44 and Pioneer 11CFT) were determined. Wheat and legume species were sown in separate plots and these plants were harvested when wheat reached the dough stage about 180 days after plant emergence. The present study was conducted in a factorial (3 legume species×3 inoculants×5 mixtures) arrangement design. Results showed that effects of legume species on ADF, crude ash, pH, lactic acid bacteria, enterobacteria, yeast and mold, lactic acid, acetic acid, propionic acid, butyric acid and ammonia nitrogen were significant (P < 0.05). Crude protein, silage fermentation features and microbial populations were affected (P<0.05) by inoculants. Effects of mixture ratios on dry matter, chemical compositions, relative feed value, fermentation parameters of silages were significant (P < 0.05). It was determined that ensiling the 50 % wheat with 50% grass pea with the use of inoculant 1188 as an additive could give a good result both in terms of nutritive value and fermentation quality. Bangladesh J. Bot. 52(3): 775-782, 2023 (September)
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Al-Azzauy, Ahmed A. M., Dalya B. Hana y Mayssaa E. Abdalah. "The use of the water extract of Rosa spp petals as a bacterial growth medium". Al Mustansiriyah Journal of Pharmaceutical Sciences 10, n.º 2 (1 de diciembre de 2011): 84–93. http://dx.doi.org/10.32947/ajps.v10i2.298.
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In a pioneer study, simple water extract for the red petals of Rosa spp. was prepared under sterile conditions, then used for the first time as experimental bacterial culture medium for the growth of the bacteria: Pseudomonas aeruginosa, Proteus vulgaris, Staphylococcus aureus, Escherichia coli, Streptococcus pneumoniae and Klebsiella pneumoniae; the medium was used as alternative culture medium for the routine culture media (Nutrient agar, MacConkey agar and blood agar) that used for the growth of these genera in the laboratories.All the genera showed active growth after 24 hours when it used directly as a liquid culture medium. The extract was used also to enrich the agar-agar and cultivated with the same bacteria; it showed a noticeable growth. The results suggest that this extract is a suitable culture medium; it could be used instead ofthe routine culture media that used in the cultivation of these bacteria in the laboratories. It also represents important, rich nutritional medium as those that isused in the routine laboratory work.
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Reni Ustiatik, Yulia Nuraini, Suharjono y Eko Handayanto. "Isolation of Mercury-Resistant Endophytic and Rhizosphere Microorganisms from Grasses in Abandoned Gold Mining Area". Jurnal Agronomi Indonesia (Indonesian Journal of Agronomy) 49, n.º 1 (30 de abril de 2021): 97–104. http://dx.doi.org/10.24831/jai.v49i1.32356.
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There were about 900 hotspots of artisanal and small scale gold mining (ASGM) in Indonesia that recovered gold through amalgamation and cyanidation techniques. Amalgamation technique causes mercury (Hg) pollution to the soil. This study was a preliminary study that aimed to isolate Hg-resistant endophytic and rhizosphere microorganisms from pioneer grasses in the Hg-polluted soil. The most potential microorganism will be used for Hg phytoremediation in the future study. Pioneer grasses were collected from the abandoned gold mining area in Central Lombok Regency, West Nusa Tenggara. Total microorganisms were counted using Colony Forming Unit (CFU) or Standard Plate Count. The microorganism colony was characterized based on morphological characteristics. Hg-resistant endophytic and rhizosphere microorganisms were successfully isolated from pioneer grass (Cynodon dactylon and Eleusine indica) in the study site. The colonies of rhizosphere microorganisms were diverse morphologically compared to endophytic microorganisms based on the number of isolated microorganisms, 20 isolates and 17 isolates, respectively. The density of rhizosphere microorganisms was higher (96%) than endophytic microorganisms (4%). The density of rhizosphere bacteria and fungi were 47x103 and 2x103 CFU g-1, respectively. However, the density of endophytic bacteria and fungi were only 2x103 and 1x103 CFU g-1, respectively.
Keywords: endophytic microorganism, Hg-resistant, microorganism density, rhizosphere microorganism
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Muharraran, Firdha, Idamawati Nababan y Usvah. "Effectiveness Evaluation of Fenugreek Seeds Ethanol Extract (Trigonella foenum-graecum) Against Bacterial Growth Streptococcus sanguinis: In Vitro Study". Indonesian Journal of Rheumatology 13, n.º 3 (5 de enero de 2024): 797–800. http://dx.doi.org/10.37275/ijr.v13i3.278.
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Introduction: Streptococcus sanguinis is a pioneer bacteria in the formation of dental plaque that causes caries. Fenugreek (Trigonella-foenum-graecum L.) is a medicinal plant that has antibacterial properties because it contains alkaloids, tannins, flavonoids, glycosides, and terpenoids. The aim of this research was to determine the effectiveness of fenugreek seed extract with concentrations of 25%, 50%, 75%, and 100% on bacterial growth of S. sanguinis.
Methods: This study is the post-test-only control group. The research sample is a pure culture of Streptococcus sanguinis bacteria ATCC 10556. Antibacterial testing uses the disc diffusion method by sight diameter bacterial inhibition zone. Data was analyzed using the Kruskal-Wallis test.
Results: The test results showed that the ethanol extract of fenugreek seeds with concentrations of 25%, 50%, 75%, and 100% had an inhibitory zone against the growth of Streptococcus sanguinis bacteria with the average diameter of the inhibitory zone for each concentration being 7.77 ± 6.13 mm. 9.90 ± 8.09, 12.22 ± 5.05, and 14.75 ± 4.83 mm, but the antibacterial effectiveness did not have a significant difference with a value of p = 0.12.
Conclusion: The ethanol extract of fenugreek seeds has antibacterial activity against the Streptococcus sanguinis bacteria but is not significant.
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Xia, Yue, Ruipeng He, Wanru Xu y Jie Zhang. "The Zoige pioneer plant Leymus secalinus has different endophytic bacterial community structures to adapt to environmental conditions". PeerJ 11 (18 de mayo de 2023): e15363. http://dx.doi.org/10.7717/peerj.15363.
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Background Leymus secalinus is a pioneer plant grown in the Zoige desertified alpine grassland and it is also one of the dominant plant species used for environmental remediation. L. secalinus plays a large role in vegetation reconstruction in sandy land, but the abundance and diversity of its endophytes have not yet been investigated. Objectives This study was performed to investigate the changes in the endophytic bacterial community structure of L. secalinus under different ecological environments and to analyze the effects of environmental changes and different plant tissues on the L. secalinus endophytic bacteria. Methods Leaf, stem, and root tissue samples of L. secalinus were collected from Zoige Glassland (Alpine sandy land) and an open field nursery (Control). DNA was extracted and the 16S ribosomal DNA was amplified. The sequence library was sequenced on an Illumina MiSeq platform and clustered by operational taxonomic units (OTUs). α-diversity and β-diversity analyses, species diversity analyses, functional prediction, and redundancy (RDA) analyses for the soil physicochemical properties were conducted. Results α-diversity and β-diversity analyses showed that the endophytic bacteria in L. secalinus varied in different areas and tissues. The abundance of Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium, which is related to nitrogen fixation, increased significantly in the L. secalinus found in the Zoige Grassland. Moreover, the abundance of nutrition metabolism and anti-stress abilities increased in functional prediction in the desert samples. The soil physicochemical properties had an insignificant influence on bacterial diversity. Conclusion The changes in the endophytic bacterial community structure in L. secalinus were significant and were caused by environmental alterations and plant choice. The endophytic bacteria in L. secalinus grown in alpine sandy land may have greater anti-stress properties and the ability to fix nitrogen, which has potential value in environmental remediation and agricultural production.
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Li, Qiqian, Siyu Yao, Hua Wen, Wenqi Li, Ling Jin y Xiuxiang Huang. "Improving Lead Phytoremediation Using Endophytic Bacteria Isolated from the Pioneer Plant Ageratina adenophora (Spreng.) from a Mining Area". Toxics 12, n.º 4 (16 de abril de 2024): 291. http://dx.doi.org/10.3390/toxics12040291.
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This study aimed to isolate and characterise endophytic bacteria from the pioneer plant Ageratina adenophora in a mining area. Seven strains of metal-resistant endophytic bacteria that belong to five genera were isolated from the roots of A. adenophora. These strains exhibited various plant growth-promoting (PGP) capabilities. Sphingomonas sp. ZYG-4, which exhibited the ability to secrete indoleacetic acid (IAA; 53.2 ± 8.3 mg·L−1), solubilize insoluble inorganic phosphates (Phosphate solubilization; 11.2 ± 2.9 mg·L−1), and regulate root ethylene levels (1-aminocyclopropane-1-carboxylic acid deaminase activity; 2.87 ± 0.19 µM α-KB·mg−1·h−1), had the highest PGP potential. Therefore, Sphingomonas sp. ZYG-4 was used in a pot experiment to study its effect on the biomass and Pb uptake of both host (Ageratina adenophora) and non-host (Dysphania ambrosioides) plants. Compared to the uninoculated control, Sphingomonas sp. ZYG-4 inoculation increased the biomass of shoots and roots by 59.4% and 144.4% for A. adenophora and by 56.2% and 57.1% for D. ambrosioides, respectively. In addition, Sphingomonas sp. ZYG-4 inoculation enhanced Pb accumulation in the shoot and root by 268.9% and 1187.3% for A. adenophora, and by 163.1% and 343.8% for D. ambrosioides, respectively, compared to plants without bacterial inoculation. Our research indicates that endophytic bacteria are promising candidates for enhancing plant growth and facilitating microbe-assisted phytoremediation in heavy metal-contaminated soil.
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Doghri, Ibtissem, Emilie Portier, Florie Desriac, Jean Michel Zhao, Alexis Bazire, Alain Dufour, Vincent Rochette, Sophie Sablé y Isabelle Lanneluc. "Anti-Biofilm Activity of a Low Weight Proteinaceous Molecule from the Marine Bacterium Pseudoalteromonas sp. IIIA004 against Marine Bacteria and Human Pathogen Biofilms". Microorganisms 8, n.º 9 (25 de agosto de 2020): 1295. http://dx.doi.org/10.3390/microorganisms8091295.
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Pseudoalteromonas bacteria are known as potential bioactive metabolite producers. Because of the need to obtain natural molecules inhibiting the bacterial biofilms, we investigated the biofilm inhibitory activity of the marine bacterium Pseudoalteromonas sp. IIIA004 against the pioneer surface colonizer Roseovarius sp. VA014. The anti-biofilm activity from the culture supernatant of Pseudoalteromonas sp. IIIA004 (SNIIIA004) was characterized in microtiter plates (static conditions/polystyrene surface) and in flow cell chambers (dynamic conditions/glass surface). The Pseudoalteromonas exoproducts exhibited an inhibition of Roseovarius sp. VA014 biofilm formation as well as a strong biofilm dispersion, without affecting the bacterial growth. Microbial adhesion to solvent assays showed that SNIIIA004 did not change the broad hydrophilic and acid character of the Roseovarius strain surface. Bioassay-guided purification using solid-phase extraction and C18 reverse-phase-high-performance liquid chromatography (RP-HPLC) was performed from SNIIIA004 to isolate the proteinaceous active compound against the biofilm formation. This new anti-biofilm low weight molecule (< 3kDa), named P004, presented a wide spectrum of action on various bacterial biofilms, with 71% of sensitive strains including marine bacteria and human pathogens. Pseudoalteromonas sp. IIIA004 is a promising source of natural anti-biofilm compounds that combine several activities.
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Gorreja, Frida, Stephen TA Rush, Dennis L. Kasper, Di Meng y W. Allan Walker. "The developmentally regulated fetal enterocyte gene, ZP4, mediates anti-inflammation by the symbiotic bacterial surface factor polysaccharide A on Bacteroides fragilis". American Journal of Physiology-Gastrointestinal and Liver Physiology 317, n.º 4 (1 de octubre de 2019): G398—G407. http://dx.doi.org/10.1152/ajpgi.00046.2019.
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Initial colonizing bacteria play a critical role in completing the development of the immune system in the gastrointestinal tract of infants. Yet, the interaction of colonizing bacterial organisms with the developing human intestine favors inflammation over immune homeostasis. This characteristic of bacterial-intestinal interaction partially contributes to the pathogenesis of necrotizing enterocolitis (NEC), a devastating premature infant intestinal inflammatory disease. However, paradoxically some unique pioneer bacteria (initial colonizing species) have been shown to have a beneficial effect on the homeostasis of the immature intestine and the prevention of inflammation. We have reported that one such pioneer bacterium, Bacteroides fragilis ( B. fragilis), and its surface component polysaccharide A (PSA) inhibit IL-1β-induced inflammation in a human primary fetal small intestinal cell line (H4 cells). In this study, using transcription profiling of H4 cellular RNA after pretreatment with or without PSA before an inflammatory stimulation of IL-1β, we have begun to further determine the cellular mechanism for anti-inflammation. We show that a developmentally regulated gene, zona pellucida protein 4 ( ZP4), is uniquely elevated after IL-1β stimulation and reduced with PSA exposure. ZP4 was known as a sperm receptor-mediating species-specific binding protein in the initial life of mammals. However, its intestinal epithelial function is unclear. We found that ZP4 is a developmentally regulated gene involved with immune function and regulated by both Toll-like receptor 2 and 4. Knockdown of ZP4-affected PSA inhibited IL-8 mRNA expression in response to IL-1β. This represents an initial study of ZP4 innate immune function in immature enterocytes. This study may lead to new opportunity for efficient treatment of NEC. NEW & NOTEWORTHY This study extends previous observations to define the cellular mechanisms of polysaccharide A-induced anti-inflammation in immature enterocytes using transcription profiling of enterocyte genes after preexposure to polysaccharide A before an inflammatory stimulus with IL-1β.
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Goodridge, Lawrence D. y Stephen T. Abedon. "Bacteriophage biocontrol: the technology matures". Microbiology Australia 29, n.º 1 (2008): 48. http://dx.doi.org/10.1071/ma08048.
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Use of bacteriophages (phages) as bacterial biocontrol agents was first envisioned by the phage pioneer Felix d?Herelle, and an increasing number of peer-reviewed studies point to the potential of phages to control spoilage and pathogenic bacteria in food. Several such phage-based biocontrol products have recently received regulatory approval and some have been commercialised. Obstacles nevertheless remain before widespread implementation can be achieved. These include consumer acceptance of the addition of ?viruses? to food as well as various commercial-production issues. Reviews of basic principles of phage-based biocontrol can be found elsewhere. Here we document recent phage-biocontrol regulatory successes as well as production considerations relevant to phage utilisation as a food additive.
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Rivera Santillan, R. E., F. Patricio Ramirez y V. D. Aguilar Perez. "Bioleaching of Aluminum Slags with Thermophilic Bacteria". Advanced Materials Research 1130 (noviembre de 2015): 414–17. http://dx.doi.org/10.4028/www.scientific.net/amr.1130.414.
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The recovery of metallic aluminum from the waste generated in the production of secondary aluminum by bioleaching process using the nutrient medium MKM was investigated. The development of this project was carried out due to the need to treat waste foundry which have a major impact on the environment, using environmentally friendly techniques, such as bioleaching. At work, bioleaching of smelting slag of aluminum generated in the laboratories of the Department of Metallurgy, Faculty of Chemistry, UNAM, was reported. Tests were conducted using thermophilic microorganisms at 70°C in an orbital incubator at natural pH, obtaining metallic clean aluminum, aluminum in solution and salts solution. The pH, bacterial growth and redox potential were monitored daily. We conclude that bioleaching of aluminum slags is feasible. The lack of information about the treatment of this type of industrial waste, makes this research is pioneer in this field.
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Felgner, Sebastian, Dino Kocijancic, Michael Frahm y Siegfried Weiss. "Bacteria in Cancer Therapy: Renaissance of an Old Concept". International Journal of Microbiology 2016 (2016): 1–14. http://dx.doi.org/10.1155/2016/8451728.
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The rising incidence of cancer cases worldwide generates an urgent need of novel treatment options. Applying bacteria may represent a valuable therapeutic variant that is intensively investigated nowadays. Interestingly, the idea to apply bacteria wittingly or unwittingly dates back to ancient times and was revived in the 19th century mainly by the pioneer William Coley. This review summarizes and compares the results of the past 150 years in bacteria mediated tumor therapy from preclinical to clinical studies. Lessons we have learned from the past provide a solid foundation on which to base future efforts. In this regard, several perspectives are discussed by which bacteria in addition to their intrinsic antitumor effect can be used as vector systems that shuttle therapeutic compounds into the tumor. Strategic solutions like these provide a sound and more apt exploitation of bacteria that may overcome limitations of conventional therapies.
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Díaz, Carolina, Patricia Schilardi y Mónica Fernández Lorenzo de Mele. "Influence of Surface Sub-micropattern on the Adhesion of Pioneer Bacteria on Metals". Artificial Organs 32, n.º 4 (abril de 2008): 292–98. http://dx.doi.org/10.1111/j.1525-1594.2008.00545.x.
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Minamisawa, Kiwamu, Kiyo Nishioka, Taro Miyaki, Bin Ye, Takuya Miyamoto, Mu You, Asami Saito et al. "Anaerobic Nitrogen-Fixing Consortia Consisting of Clostridia Isolated from Gramineous Plants". Applied and Environmental Microbiology 70, n.º 5 (mayo de 2004): 3096–102. http://dx.doi.org/10.1128/aem.70.5.3096-3102.2004.
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ABSTRACT We report here the existence of anaerobic nitrogen-fixing consortia (ANFICOs) consisting of N2-fixing clostridia and diverse nondiazotrophic bacteria in nonleguminous plants; we found these ANFICOs while attempting to overcome a problem with culturing nitrogen-fixing microbes from various gramineous plants. A major feature of ANFICOs is that N2 fixation by the anaerobic clostridia is supported by the elimination of oxygen by the accompanying bacteria in the culture. In a few ANFICOs, nondiazotrophic bacteria specifically induced nitrogen fixation of the clostridia in culture. ANFICOs are widespread in wild rice species and pioneer plants, which are able to grow in unfavorable locations. These results indicate that clostridia are naturally occurring endophytes in gramineous plants and that clostridial N2 fixation arises in association with nondiazotrophic endophytes.
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Striganavičiūtė, Greta, Jonas Žiauka, Vaida Sirgedaitė-Šėžienė y Dorotėja Vaitiekūnaitė. "Impact of Plant-Associated Bacteria on the In Vitro Growth and Pathogenic Resistance against Phellinus tremulae of Different Aspen (Populus) Genotypes". Microorganisms 9, n.º 9 (7 de septiembre de 2021): 1901. http://dx.doi.org/10.3390/microorganisms9091901.
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Aspens (Populus tremula and its hybrids), economically and ecologically important fast-growing trees, are often damaged by Phellinus tremulae, a rot-causing fungus. Plant-associated bacteria can be used to increase plant growth and resistance; however, no systematic studies relating the activity of symbiotic bacteria to aspen resistance against Phellinus tremulae have been conducted so far. The present pioneer study investigated the responses of two Populus tremula and two P. tremula × P. tremuloides genotypes to in vitro inoculations with, first, either Pseudomonas sp. or Paenibacillus sp. bacteria (isolated originally from hybrid aspen tissue cultures and being most closely related to Pseudomonas oryzihabitans and Paenibacillus tundrae, respectively) and, in the subsequent stage, with Phellinus tremulae. Both morphological parameters of in vitro-grown plants and biochemical content of their leaves, including photosynthesis pigments and secondary metabolites, were analyzed. It was found that both Populus tremula × P. tremuloides genotypes, whose development in vitro was significantly damaged by Phellinus tremulae, were characterized by certain responses to the studied bacteria: decreased shoot development by both Paenibacillus sp. and Pseudomonas sp. and increased phenol content by Pseudomonas sp. In turn, these responses were lacking in both Populus tremula genotypes that showed in vitro resistance to the fungus. Moreover, these genotypes showed positive long-term growth responses to bacterial inoculation, even synergistic with the subsequent fungal inoculation. Hence, the studied bacteria were demonstrated as a potential tool for the improved in vitro propagation of fungus-resistant aspen genotypes.
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Loo, C. Y., D. A. Corliss y N. Ganeshkumar. "Streptococcus gordonii Biofilm Formation: Identification of Genes that Code for Biofilm Phenotypes". Journal of Bacteriology 182, n.º 5 (1 de marzo de 2000): 1374–82. http://dx.doi.org/10.1128/jb.182.5.1374-1382.2000.
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ABSTRACT Viridans streptococci, which include Streptococcus gordonii, are pioneer oral bacteria that initiate dental plaque formation. Sessile bacteria in a biofilm exhibit a mode of growth that is distinct from that of planktonic bacteria. Biofilm formation ofS. gordonii Challis was characterized using an in vitro biofilm formation assay on polystyrene surfaces. The same assay was used as a nonbiased method to screen isogenic mutants generated by Tn916 transposon mutagenesis for defective biofilm formation. Biofilms formed optimally when bacteria were grown in a minimal medium under anaerobic conditions. Biofilm formation was affected by changes in pH, osmolarity, and carbohydrate content of the growth media. Eighteen biofilm-defective mutants ofS. gordonii Challis were identified based on Southern hybridization with a Tn916-based probe and DNA sequences of the Tn916-flanking regions. Molecular analyses of these mutants showed that some of the genes required for biofilm formation are involved in signal transduction, peptidoglycan biosynthesis, and adhesion. These characteristics are associated with quorum sensing, osmoadaptation, and adhesion functions in oral streptococci. Only nine of the biofilm-defective mutants had defects in genes of known function, suggesting that novel aspects of bacterial physiology may play a part in biofilm formation. Further identification and characterization of biofilm-associated genes will provide insight into the molecular mechanisms of biofilm formation of oral streptococci.
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Haniya Diva Kurotul Aini, Hartini Benita, Prawati Nuraini y Soegeng Wahluyo. "The potential inhibitory power of cinnamon extract (Cinnamomum burmanii) toward the growth of Streptococcus gordonii bacteria". World Journal of Advanced Research and Reviews 21, n.º 1 (30 de enero de 2024): 728–32. http://dx.doi.org/10.30574/wjarr.2024.21.1.0061.
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Introduction: S. gordonii are pioneer bacteria which play a vital role in the process of caries formation. As an alternative of caries prevention agent with minimal side effects, a natural plant, namely cinnamon, can be used. The essential oil in cinnamon contains cinnamaldehyde and eugenol compounds which have been proven effective in inhibiting bacterial growth. Objective: To determine the effect of cinnamon extract on inhibiting the growth of S. gordonii. Method: The research was carried out using analytical methods in an in vitro laboratory experiment with a posttest only control group design. The sample used in this study was S. gordonii bacteria in Brain Heart Infusion Broth (BHIB) media which was incubated at 37°C for 24 hours. Determination of the inhibitory power of cinnamon extract is carried out by giving cinnamon extract concentrations of 50%, 12.5%, 3.125%, and 0.78% to each paper disk on agar media. Statistical analysis was performed with IBM SPSS Statistics. Results: The inhibitory power of cinnamon extract concentration groups on the growth of S. gordonii bacteria had a value of Sig = 0.000 (Sig < 0.05) so there is a significant difference in the inhibitory power between cinnamon extract concentration groups. Conclusion: Based on the results, it can be concluded that the higher the concentration of cinnamon extract used, the more effectively it can inhibit the growth ofS. gordonii bacteria.
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Putri, Deby Kania Tri, Indah Listiana Kriswandini y Muhammad Luthfi. "Characterization of Streptococcus sanguis molecular receptors for Streptococcus mutans binding molecules". Dental Journal (Majalah Kedokteran Gigi) 49, n.º 4 (31 de diciembre de 2016): 213. http://dx.doi.org/10.20473/j.djmkg.v49.i4.p213-216.
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Background: Dental caries is a major problem in oral cavity. If dental caries causes cavity, the structure of dental hard tissue will not be reversible because of damage in the structure of the hard tissue. The early pathogenesis mechanism of dental caries is an adhesion interaction between cariogenic Streptococcus mutans microorganisms and tooth surface pellicles. The attachment involves a specific molecular component interaction between the bacterial complement molecules and the surface of the host. Streptococcus sanguis as a dominant ecology at the beginning of bacterial plaque aggregation will colonize the tooth surface earlier than S. mutans. The surface of bacterial cells can express some adesin. The bacteria also can express receptors for adhesins of other bacteria. Specific receptors for adhesions of S. Mutans bacteria are not only found in the pellicles, but also present in pioneer bacteria, such as S. sanguis. Adhesion between those bacteria is called as coagregation. Purpose: This study aimed to analyze the characterization of Streptococcus sanguis molecular receptors for Streptococcus mutans binding molecules. Method: This study used a sonication method for protein isolation of S. mutans and S. sanguis bacterial biofilms, as well as electrophoresis method using 12 % SDS-PAGE gel and Western Blot analysis. Result: Results of the protein profile analysis of S. mutans biofilms using 12% SDS-PAGE showed that there were 17 bands, each of which molecular weights was 212, 140, 81, 65, 61, 48, 45, 44, 40, 39, 33 , 25, 23, 19, 17, 12, and 11 kDa. On the other hand, results of the protein profile analysis of S. sanguis biofilms using 12% SDS-PAGE showed that there were 15 bands, each of which molecular weight was 130, 85, 65, 61, 48, 46, 40, 37, 29, 25, 23, 21, 17, 15, and 12 kDa. And, results of the analysis of S. sanguis receptor molecules using Western blot showed that there were three bands, each of which molecular weight was 130, 85, and 40 kDa. Conclusion: S. sanguis bacteria have specific receptor molecules for S. mutans bacteria with the molecular weight of 130, 85, and 40 kDa.
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Brito, Tauane Santos, Renan Pan, Lenir Aparecida Buss, João Paulo Fonesi de Carvalho, Tatiane Eberling, Alexandra Da Silva Martinez, Vandeir Francisco Guimarães y Elisiane Inês Dall'Oglio Chaves. "Growth Promotion of Burkholderia ambifaria Associated to Nitrogen Fertilization in the Initial Development of Corn". Journal of Agricultural Science 10, n.º 6 (6 de mayo de 2018): 123. http://dx.doi.org/10.5539/jas.v10n6p123.
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Growth promoting bacteria are a potential option for sustainable cultivation with lower costs, among them Burkholderia ambifaria, whose importance is mainly due to the endophytic root colonization capacity. The objective of this work was to evaluate the effect of the inoculation of growth promoting bacteria in corn plants, in vitro and in greenhouse, with different levels of nitrogen fertilization. The PIONEER® 30F53 YH maize genotype was inoculated with Burkholderia ambifaria, with 106 CFU per seed, in 12-liter polyethylene pots, filled with commercial substrate, prepared with the different nitrogen contents (N), resulting in treatments with different doses of fertilization, associated or not with bacterial inoculation. After 30 and 45 days, it was evaluated: growth promotion, epiphytic and endophytic population and nitrogen accumulation. In the in vitro experiment, inoculated seeds were cultured in test tubes containing culture medium with absence and presence of nitrogen, evaluated after 7 days. The data were submitted to analysis of variance and the means were compared by the Tukey test at 5% of probability and regression. Increased nitrogen doses in inoculated plants resulted in better morphological parameters at 45 days. In vitro bacterial inoculation, in vitro, influenced the accumulation of fresh weight of shoot, root growth and development of root hair. The endophytic potential and the accumulation of nitrogen were higher in the absence of nitrogen, but lower than the absence of bacteria and the presence of nitrogen.
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Chen, Bin, Guangfu Tang, Weiqing Guo, Jie Lei, Junhu Yao y Xiurong Xu. "Detection of the Core Bacteria in Colostrum and Their Association with the Rectal Microbiota and with Milk Composition in Two Dairy Cow Farms". Animals 11, n.º 12 (24 de noviembre de 2021): 3363. http://dx.doi.org/10.3390/ani11123363.
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As one of the pioneer bacterial sources of intestinal microbiota, the information of bacterial composition in colostrum might provide a reference for developing specific probiotics for newborn calves, especially calves fed with pasteurized milk. The present study aimed to detect the core bacteria at different taxonomic levels and the common beneficial ones in colostrum by analyzing the bacterial composition in 34 colostrum samples of healthy cows selected from two dairy farms. The results of the further analysis showed that the bacterial composition in the colostrum of the two dairy farms was different, but their four most dominant phyla were the same including Firmicutes, Bacteroidetes, Proteobacteria, and Actinobacteria. The microbiome of all colostrum samples shared ten core operational taxonomic units (OTUs), 21 core genera, and 34 core families, and most of them had no difference in relative abundance between the two farms. The ten core OTUs did not belong to the identified commensal bacteria and have not been detected by previous study. However, several core genera found in our study were also identified as core genus in a previous study. Some well-known beneficial and pathogenic bacteria including Lactobacillus plantarum, Bacillus subtilis, Acinetobacter lwoffii, and Streptococcus pneumoniae were present in the colostrum of healthy cows. However, none had a correlation with the number of somatic cell count (SCC), but the core genera Nubella and Brevundinimas and the core families Methylobacteriaceae and Caulobacteraceae positively correlated with the number of SCC. The genus Staphylococcus, Pseudomonas, and Chryseobacterium in colostrum had a positive correlation with each other, while the probiotics unidentified-Bacteroidales-S24-7-group had a negative correlation with Pseudomonas and Chryseobacterium. In addition, more than 50% bacterial OTUs in colostrum were detected in the rectal content including some strictly anaerobic bacteria that are generally present in the intestine and rumen. However, of the top 30 commonly shared bacterial genera in the colostrum and rectal feces, no genus in colostrum was positively correlated with that same genus in rectal feces. In conclusion, the bacterial composition of colostrum microbiota is greatly influenced by external factors and individuals. There were several core OTUs, and some core genus and families in the colostrum samples. Colostrum from healthy cows contained both beneficial and pathogenic bacteria and shared many common bacteria with rectal content including some gastrointestinal anaerobes.
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Cheng, Zhichao, Song Wu, Hong Pan, Xinming Lu, Yongzhi Liu y Libin Yang. "Effect of Forest Fires on the Alpha and Beta Diversity of Soil Bacteria in Taiga Forests: Proliferation of Rare Species as Successional Pioneers". Forests 15, n.º 4 (27 de marzo de 2024): 606. http://dx.doi.org/10.3390/f15040606.
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Forest fires are among the most influential drivers of changes in forest soil bacterial diversity. Nevertheless, little is known regarding the effects of forest fires on maintaining the complex interactions that preserve forest ecosystem stability. Therefore, this study characterized alterations in soil bacterial community composition and diversity within taiga forests subjected to varying disturbance intensities. Particularly, this study examined the bacterial community within a Larix gmelinii fire-burnt site in Daxinganling, analyzing the changes in bacterial community structure and function across light, moderate, and heavy fire-burnt sites, as well as a control sample site, utilizing Illumina MiSeq technology. Through an assessment of bacterial community diversity and soil physicochemical properties (moisture content (MC), pH, microbial biomass carbon (MBC), organic carbon (SOC), total nitrogen (TN), available nitrogen (AN), available phosphorus (AP), and available potassium (AP)), we explored the influence of the soil microenvironment on the soil bacterial community structure at the burnt site under different disturbance intensities. Our findings demonstrated that (1) there was no significant change in the Chao index of soil bacteria in the burnt site under different disturbance intensities, whereas the Shannon index decreased significantly (p < 0.05) and the Simpson index increased significantly (p < 0.05) in the burnt site under light and moderate disturbance. (2) The relative abundance of dominant phyla, such as Proteobacteria, Proteobacteria, and Actinobacteriota, did not change significantly in the fire-burnt site under different disturbance intensities, whereas rare species, such as Acidipila, Occallatibacter, and Acidibacter, experienced a significant increase in relative abundance at the genus level. (3) The results of principal coordinates analysis (PCoA) and canonical correlation analysis (CCA) revealed significant differences in the Beta diversity of soil bacteria in the fire-burnt site under varying interference intensities. The Beta diversity of soil bacteria exhibited significant differences (p = 0.001), with MC, pH, TN, AN, and AK identified as significant influencing factors. (4) FAPROTAX functional prediction analyses were conducted to assess the changes in soil bacteria involved in Cellulolysis, Chemoheterotrophy, and Aerobic_Chemoheterotrophy in the fire-burnt site, with the relative abundance of bacteria involved in Chemoheterotrophy being significantly increased (p < 0.05) under different disturbance intensities. Collectively, our findings demonstrated that different disturbance intensities caused by fires significantly affected the Alpha diversity, Beta diversity, and functional abundance of soil bacterial communities in taiga forests, with MC, pH, TN, AN, and AK being identified as key influencing factors. Additionally, the presence of numerous rare species suggests their role as pioneer communities in the succession of soil bacterial communities.
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Durand, A. A., P. Constant, E. Déziel y C. Guertin. "The symbiotic complex of Dendroctonus simplex: implications in the beetle attack and its life cycle". Bulletin of Entomological Research 109, n.º 6 (26 de febrero de 2019): 723–32. http://dx.doi.org/10.1017/s0007485319000051.
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AbstractThe eastern larch beetle (Dendroctonus simplex Le Conte) is recognized as a serious destructive forest pest in the upper part of North America. Under epidemic conditions, this beetle can attack healthy trees, causing severe damages to larch stands. Dendroctonus species are considered as holobionts, as they engage in multipartite interactions with microorganisms, such as bacteria, filamentous fungi, and yeasts, which are implicated in physiological processes of the insect, such as nutrition. They also play a key role in the beetle's attack, as they are responsible for the detoxification of the subcortical environment and weaken the tree's defense mechanisms. The eastern larch beetle is associated with bacteria and fungi, but their implication in the success of the beetle remains unknown. Here, we investigated the bacterial and fungal microbiota of this beetle pest throughout its ontogeny (pioneer adults, larvae and pupae) by high-throughput sequencing. A successional microbial assemblage was identified throughout the beetle developmental stages, reflecting the beetle's requirements. These results indicate that a symbiotic association between the eastern larch beetle and some of these microorganisms takes place and that this D. simplex symbiotic complex is helping the insect to colonize its host tree and survive the conditions encountered.
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Doghri, Ibtissem, Florence Brian-Jaisson, Marianne Graber, Alexis Bazire, Alain Dufour, Marie-Noëlle Bellon-Fontaine, Jean-Marie Herry et al. "Antibiofilm activity in the culture supernatant of a marine Pseudomonas sp. bacterium". Microbiology 166, n.º 3 (1 de marzo de 2020): 239–52. http://dx.doi.org/10.1099/mic.0.000878.
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In the marine environment, most solid surfaces are covered by microbial biofilms, mainly composed of bacteria and diatoms. The negative effects of biofilms on materials and equipment are numerous and pose a major problem for industry and human activities. Since marine micro-organisms are an important source of bioactive metabolites, it is possible that they synthesize natural ecofriendly molecules that inhibit the adhesion of organisms. In this work, the antibiofilm potential of marine bacteria was investigated using Flavobacterium sp. II2003 as a target. This strain is potentially a pioneer strain of bacteria that was previously selected from marine biofilms for its strong biofilm-forming ability. The culture supernatants of 86 marine heterotrophic bacteria were tested for their ability to inhibit Flavobacterium sp. II2003 biofilm formation and the Pseudomonas sp. IV2006 strain was identified as producing a strong antibiofilm activity. The Pseudomonas sp. IV2006 culture supernatant (SNIV2006) inhibited Flavobacterium sp. II2003 adhesion without killing the bacteria or inhibiting its growth. Moreover, SNIV2006 had no effect on the Flavobacterium sp. II2003 cell surface hydrophilic/hydrophobic and general Lewis acid–base characteristics, but modified the surface properties of glass, making it on the whole more hydrophilic and more alkaline and significantly reducing bacterial cell adhesion. The glass-coating molecules produced by Pseudomonas sp. IV2006 were found to probably be polysaccharides, whereas the antibiofilm molecules contained in SNIV2006 and acting during the 2 h adhesion step on glass and polystyrene surfaces would be proteinaceous. Finally, SNIV2006 exhibited a broad spectrum of antibiofilm activity on other marine bacteria such as Flavobacterium species that are pathogenic for fish, and human pathogens in both the medical environment, such as Staphylococcus aureus and Pseudomonas aeruginosa , and in the food industry, such as Yersinia enterocolitica . Thus, a wide range of applications could be envisaged for the SNIV2006 compounds, both in aquaculture and human health.
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Sharma Ghimire, Prakriti, Shichang Kang, Wasim Sajjad, Barkat Ali, Lekhendra Tripathee y Pengfei Chen. "Microbial Community Composition Analysis in Spring Aerosols at Urban and Remote Sites over the Tibetan Plateau". Atmosphere 11, n.º 5 (20 de mayo de 2020): 527. http://dx.doi.org/10.3390/atmos11050527.
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This study presents features of airborne culturable bacteria and fungi from three different sites (Lanzhou; LZ; 1520 m ASL, Lhasa; LS; 3640 m ASL and Qomolangma; ZF; 4276 m ASL) representing urban (LZ and LS) and remote sites (ZF) over the Tibetan Plateau (TP). Total suspended particle (TSP) samples were collected with an air sampler (Laoying 2030, China) on a quartz filter. Community structures of bacteria and fungi were studied and compared among three different locations. The average levels of bacterial load in the outdoor air ranged from approximately 8.03 × 101 to 3.25 × 102 CFU m–3 (Colony forming unit per m3). However, the average levels of fungal loads ranged from approximately 3.88 × 100 to 1.55 × 101 CFU m−3. Bacterial load was one magnitude higher at urban sites LZ (2.06 × 102–3.25 × 102 CFU m−3) and LS (1.96 × 102–3.23 × 102 CFU m−3) compared to remote sites ZF (8.03 × 101–9.54 × 101 CFU m−3). Similarly, the maximum fungal load was observed in LZ (1.02 × 101–1.55 × 101 CFU m−3) followed by LS (1.03 × 101–1.49 × 101 CFU m−3) and ZF (3.88 × 100–6.26 × 100 CFU m−3). However, the maximum microbial concentration was observed on the same day of the month, corresponding to a high dust storm in Lanzhou during the sampling period. The reported isolates were identified by phylogenetic analysis of 16S rRNA genes for bacteria and ITS sequences for fungi amplified from directly extracted DNA. Bacterial isolates were mostly associated with Proteobacteria, Eurotiomycetes and Bacillus, whereas fungal isolates were mostly Aspergillus and Alternaria. Overall, this is a pioneer study that provides information about the airborne microbial concentration and composition of three sites over the TP region depending on environmental parameters. This study provided preliminary insight to carry out more advanced and targeted analyses of bioaerosol in the sites presented in the study.
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Asmani, Katia, Bruno Petton, Jacqueline Le Grand, Jérôme Mounier, René Robert y Jean-Louis Nicolas. "Determination of stocking density limits for Crassostrea gigas larvae reared in flow-through and recirculating aquaculture systems and interaction between larval density and biofilm formation". Aquatic Living Resources 30 (2017): 29. http://dx.doi.org/10.1051/alr/2017023.
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The first aim of this study was to determine the stocking density limits for Pacific oyster Crassostrea gigas larvae reared in flow-through system (FTS) and recirculating aquaculture systems (RAS). The second aim was to examine biofilm formation on the larval tank wall and its interaction with larvae growth. Three larvae concentrations were tested: 50, 150, and 300 mL−1. Chemical parameters and larvae performance were measured. The biofilm was observed by scanning electron microscopy, and its bacterial composition was investigated by pyrosequencing analysis of part of the 16S rRNA gene. The highest growth (13 µm day–1), survival (87%) and metamorphosis (50%) rates were observed in FTS at 50 larvae mL–1, while lower and similar performances occurred at 150 larvae mL–1 in both systems. At 300 larvae mL−1, performances dropped with occurrence of mortality. Biofilm thickness increased with larval density. The pioneer bacteria were coccobacilli followed by filamentous bacteria. The latter constituted abundant braids at the end of rearing at high larval concentrations. The first colonizers were mainly Rhodobacteraceae (α-Proteobacteria). The filamentous bacteria were Saprospirae (Bacteroidetes) and Anaerolineae (Chloroflexi). The biofilm was also made up of other minor groups, including Actinobacteria, Planctomycetes, δ-, γ-Proteobacteria, and Flavobacteriales. The biofilm's composition was more similar to that found in a sewage reactor than in open-sea collectors, which might negatively influence larval rearing due to potential metabolites. This first study on biofilms provides insights into the interaction between rearing density and larvae performance.
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Gatti, Lucrezia, Federica Troiano, Violetta Vacchini, Francesca Cappitelli y Annalisa Balloi. "An In Vitro Evaluation of the Biocidal Effect of Oregano and Cloves’ Volatile Compounds against Microorganisms Colonizing an Oil Painting—A Pioneer Study". Applied Sciences 11, n.º 1 (24 de diciembre de 2020): 78. http://dx.doi.org/10.3390/app11010078.
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In this study, the biocidal activity of two plant derivatives (oregano and cloves’ essential oils—EOs) was evaluated, as a potential innovative and eco-friendly cleaning method for canvas paintings. The object of the study was the oil painting on canvas entitled “Studio di nudo” (Giovanni Maria Mossa, 1921), showing stains caused by microorganisms. The research focused on: (1) isolation and identification of microorganisms associated with discolorations on the obverse and reverse sides of the canvas; (2) evaluation of biocidal activity of selected EOs against fungal and bacterial collections. The phylogenetic identification was conducted with both cultivation and molecular methods. The canvas was mainly colonized by Penicillium, Aspergillus, and Cephaloteca fungal genera and by bacteria of the Bacillus genus. To evaluate the biocidal effect of the EOs’ volatile components only, an antibiogram assay (agar disc diffusion method) and a customized assay (named the contactless test) were conducted. Tested EOs showed antimicrobial activity on fungi and bacteria. However, compared to cloves, oregano EO exhibited a better inhibition activity both in contact and contactless tests. The work is pioneering for the use of EOs’ volatile compounds against oil painting biodeteriogens, and gives insights into possible extended, innovative and eco-friendly cleaning methods for painting control procedures.
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Flores-Duarte, Noris J., Enrique Mateos-Naranjo, Susana Redondo-Gómez, Eloísa Pajuelo, Ignacio D. Rodriguez-Llorente y Salvadora Navarro-Torre. "Role of Nodulation-Enhancing Rhizobacteria in the Promotion of Medicago sativa Development in Nutrient-Poor Soils". Plants 11, n.º 9 (26 de abril de 2022): 1164. http://dx.doi.org/10.3390/plants11091164.
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Legumes are usually used as cover crops to improve soil quality due to the biological nitrogen fixation that occurs due to the interaction of legumes and rhizobia. This symbiosis can be used to recover degraded soils using legumes as pioneer plants. In this work, we screened for bacteria that improve the legume–rhizobia interaction in nutrient-poor soils. Fourteen phosphate solubilizer-strains were isolated, showing at least three out of the five tested plant growth promoting properties. Furthermore, cellulase, protease, pectinase, and chitinase activities were detected in three of the isolated strains. Pseudomonas sp. L1, Chryseobacterium soli L2, and Priestia megaterium L3 were selected to inoculate seeds and plants of Medicago sativa using a nutrient-poor soil as substrate under greenhouse conditions. The effects of the three bacteria individually and in consortium showed more vigorous plants with increased numbers of nodules and a higher nitrogen content than non-inoculated plants. Moreover, bacterial inoculation increased plants’ antioxidant activities and improved their development in nutrient-poor soils, suggesting an important role in the stress mechanisms of plants. In conclusion, the selected strains are nodulation-enhancing rhizobacteria that improve leguminous plants growth and nodulation in nutrient-poor soils and could be used by sustainable agriculture to promote plants’ development in degraded soils.
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Nauer, P. A., B. Dam, W. Liesack, J. Zeyer y M. H. Schroth. "Activity and diversity of methane-oxidizing bacteria in glacier forefields on siliceous and calcareous bedrock". Biogeosciences 9, n.º 6 (25 de junio de 2012): 2259–74. http://dx.doi.org/10.5194/bg-9-2259-2012.
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Abstract. The global methane (CH4) cycle is largely driven by methanogenic archaea and methane-oxidizing bacteria (MOB), but little is known about their activity and diversity in pioneer ecosystems. We conducted a field survey in forefields of 13 receding Swiss glaciers on both siliceous and calcareous bedrock to investigate and quantify CH4 turnover based on soil-gas CH4 concentration profiles, and to characterize the MOB community by sequencing and terminal restriction fragment length polymorphism (T-RFLP) analysis of pmoA. Methane turnover was fundamentally different in the two bedrock categories. Of the 36 CH4 concentration profiles from siliceous locations, 11 showed atmospheric CH4 consumption at concentrations of ~1–2 μL L−1 with soil-atmosphere CH4 fluxes of –0.14 to –1.1 mg m−2 d−1. Another 11 profiles showed no apparent activity, while the remaining 14 exhibited slightly increased CH4 concentrations of ~2–10 μL L−1 , most likely due to microsite methanogenesis. In contrast, all profiles from calcareous sites suggested a substantial, yet unknown CH4 source below our sampling zone, with soil-gas CH4 concentrations reaching up to 1400 μL L−1. Remarkably, most soils oxidized ~90 % of the deep-soil CH4, resulting in soil-atmosphere fluxes of 0.12 to 31 mg m−2 d−1. MOB showed limited diversity in both siliceous and calcareous forefields: all identified pmoA sequences formed only 5 operational taxonomic units (OTUs) at the species level and, with one exception, could be assigned to either Methylocystis or the as-yet-uncultivated Upland Soil Cluster γ (USCγ). The latter dominated T-RFLP patterns of all siliceous and most calcareous samples, while Methylocystis dominated in 4 calcareous samples. Members of Upland Soil Cluster α (USCα) were not detected. Apparently, USCγ adapted best to the oligotrophic cold climate conditions at the investigated pioneer sites.
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Neumair, Julia, Martin Elsner y Michael Seidel. "Flow-Based Chemiluminescence Microarrays as Screening Platform for Affinity Binders to Capture and Elute Bacteria". Sensors 22, n.º 22 (8 de noviembre de 2022): 8606. http://dx.doi.org/10.3390/s22228606.
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Affinity describes the non-covalent but selective interaction between an affinity binder (e.g., proteins, antibiotics, or antibodies) and its counterpart (e.g., bacteria). These affinity binders can serve to detect bacteria and respond to the need for selective concentration via affinity chromatography for trace analysis. By changing the pH value or salt and protein contents, affinity bindings can be reversed, and bacteria can be recovered for characterisation. Analytical microarrays use multiple affinity binders immobilised on the surface in a distinct pattern, which immensely reduces screening time for the discovery of superior binding motifs. Here, flow-based microarray systems can inform not only about binding, but also about desorption. In this work, we pioneer a screening assay for affinity binders against both gram-positive and negative bacteria based on an automated flow-based chemiluminescence (CL) microarray. Biotinylation of model organisms E. coli and E. faecalis enabled labelling with horseradish-peroxidase-coupled streptavidin, and detection with CL. Polymyxin B, an antibiotic against gram-negative bacteria, was found to bind both E. coli and E. faecalis. Simultaneous screening for desorption methods unexpectedly revealed methyl alpha-D-mannopyranoside as a promising buffer for desorption from Polymyxin B. This proof-of-principle study shows that our new platform greatly facilitates the screening of new affinity binders against bacteria, with promise for future automation.
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Amat, Samat, Devin B. Holman, Kaycie Schmidt, kacie L. L. McCarthy, Sheri T. T. Dorsam, Alison K. K. Ward, Pawel P. P. Borowicz et al. "PSII-B-28 Investigation of the presence of bacterial microbiota in 12-week-old bovine fetuses". Journal of Animal Science 99, Supplement_3 (8 de octubre de 2021): 352. http://dx.doi.org/10.1093/jas/skab235.646.
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Abstract A recent study reported the existence of a diverse microbiota in 5-to-7-month-old calf fetuses, suggesting that colonization of the bovine gut with so-called “pioneer” microbiota may begin during mid-gestation. In the present study, we investigated the microbiota in bovine fetuses at early gestation. Amniotic and allantoic fluids, and intestinal and placental (cotyledon) tissue samples harvested from fetuses (n = 33) on day 83 of gestation were processed for the assessment of fetal microbiota using 16S rRNA gene sequencing. The sequencing results revealed that a diverse and complex microbial community was present in allantoic and amniotic fluids, and fetal intestine and placenta on day 83 of gestation in beef cattle. Microbial community structure was significantly different between allantoic and amniotic fluid, and intestinal and placental microbiota (0.047 ≥ R2 ≥ 0.019, P ≤ 0.031). Allantoic fluid had a greater (P < 0.05) microbial richness (number of OTUs) (122 ± 10) compared to amniotic fluid (84 ± 6), intestine (63 ± 7) and placenta (66 ± 6). Microbial diversity (Shannon index) was similar for the intestinal and placental samples, and both were less diverse compared to the fetal fluid microbiota (P < 0.05). At the phylum level, 39 different archaeal and bacterial phyla were detected across all fetal samples, with Proteobacteria (55%), Firmicutes (16.2%), Actinobacteria (13.6%) and Bacteroidetes (5%) predominating. Among the 20 most relatively abundant bacterial genera, Acidovorax, Acinetobacter, Brucella, Corynebacterium, Enterococcus, Exiguobacterium and Stenotrophomonas differed by fetal sample type (P < 0.05). A total of 55 taxa were shared among the four different microbial communities. qPCR of bacteria in the intestine and placenta samples as well as scanning electron microscopy imaging of fetal fluids provided additional evidence for the presence of a microbiota in these samples. Overall, the results of this study indicate that colonization with pioneer microbiota may occur during early gestation in bovine fetuses.
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Anggraini, Fitri, Mieke Hemiawati Satari y Marry Siti Mariam. "Bacterial inhibition test of methanolic extracts of strawberry (Fragraia x ananassa Duchesne), lime (Citrus aurantifolia), and radish (Raphanus sativus L.), towards Streptococcus Sanguis ATCC 10556". Padjadjaran Journal of Dentistry 30, n.º 2 (31 de julio de 2018): 98. http://dx.doi.org/10.24198/pjd.vol30no2.18325.
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Introduction: Caries are initiated by the plaque formation on the tooth surface, due to the interaction between food debris and bacteria in the mouth. The pioneer bacterium of plaque formation is Streptococcus sanguis. The Strawberry fruit, lime fruit, and radish root are part of the plant that contains antibacterial substances. Flavonoid, tannin, saponin, alkaloid, polyphenol, terpenoid and quinon as antibacterial substances. This study aimed to evaluate strawberry fruit, lime fruit, and radish root methanol extract can inhibit Streptococcus sanguis ATCC 10556. Therefore, strawberry, lime, and radish can be made into mouthwash, bubble gum, or toothpaste to prevent plaque formation. Methods: This study used a Kirby-Bauer diffusion test as the inhibition test. Results: The result of this study that the biggest inhibition zone was lime methanol extract 20,000 ppm, and the smallest one was radish methanol extract 5,000 ppm. Conclusion: Strawberry fruit, lime fruit peel, and radish root methanol extract and their combination had the effect of inhibiting bacterial growth synergistically against Streptococcus sanguis ATCC 10556.
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Cole, Michael F., Stacey Bryan, Mishell K. Evans, Cheryl L. Pearce, Michael J. Sheridan, Patricia A. Sura, Raoul L. Wientzen y George H. W. Bowden. "Humoral Immunity to Commensal Oral Bacteria in Human Infants: Salivary Secretory Immunoglobulin A Antibodies Reactive withStreptococcus mitis biovar 1, Streptococcus oralis, Streptococcus mutans, andEnterococcus faecalis during the First Two Years of Life". Infection and Immunity 67, n.º 4 (1 de abril de 1999): 1878–86. http://dx.doi.org/10.1128/iai.67.4.1878-1886.1999.
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ABSTRACT Secretory immunoglobulin A (SIgA) antibodies reactive with the pioneer oral streptococci Streptococcus mitis biovar 1 andStreptococcus oralis, the late oral colonizerStreptococcus mutans, and the pioneer enteric bacteriumEnterococcus faecalis in saliva samples from 10 human infants from birth to age 2 years were analyzed. Low levels of salivary SIgA1 and SIgA2 antibodies reactive with whole cells of all four species were detected within the first month after birth, even thoughS. mutans and E. faecalis were not recovered from the mouths of the infants during the study period. Although there was a fivefold increase in the concentration of SIgA between birth and age 2 years, there were no differences between the concentrations of SIgA1 and SIgA2 antibodies reactive with the four species over this time period. When the concentrations of SIgA1 and SIgA2 antibodies reactive with all four species were normalized to the concentrations of SIgA1 and SIgA2 in saliva, SIgA1 and SIgA2 antibodies reactive with these bacteria showed a significant decrease from birth to 2 years of age. Adsorption of each infant’s saliva with cells of one species produced a dramatic reduction of antibodies recognizing the other three species. Sequential adsorption of saliva samples removed all SIgA antibody to the bacteria, indicating that the SIgA antibodies were directed to antigens shared by all four species. The induction by the host of a limited immune response to common antigens that are likely not involved in adherence may be among the mechanisms that commensal streptococci employ to persist in the oral cavity.
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van Hoogmoed, Chris G., Henny C. van der Mei y Henk J. Busscher. "The Influence of Biosurfactants Released byS. mitisBMS on the Adhesion of Pioneer Strains and Cariogenic Bacteria". Biofouling 20, n.º 6 (septiembre de 2004): 261–67. http://dx.doi.org/10.1080/08927010400027050.
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Sun, Yuan, Yanhe Lang, ZhengYu Yan, Lei Wang y Zhizhou Zhang. "High-throughput sequencing analysis of marine pioneer surface-biofilm bacteria communities on different PDMS-based coatings". Colloids and Surfaces B: Biointerfaces 185 (enero de 2020): 110538. http://dx.doi.org/10.1016/j.colsurfb.2019.110538.
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Cheng, Hao, Yong Liu, Zhao-Yu Jiang y You-Shao Wang. "Radial oxygen loss is correlated with nitrogen nutrition in mangroves". Tree Physiology 40, n.º 11 (24 de julio de 2020): 1548–60. http://dx.doi.org/10.1093/treephys/tpaa089.
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Abstract The present study aimed to explore the possible functions of radial oxygen loss (ROL) on mangrove nutrition. A field survey was conducted to explore the relations among ROL, root anatomy and leaf N in different mangrove species along a continuous tidal gradient. Three mangroves with different ROL (Avicennia marina [A. marina], Kandelia obovata and Rhizophora stylosa) were then selected to further explore the dynamics of N at the root-soil interface. The results showed that seaward pioneer mangrove species such as A. marina appeared to exhibit higher leaf N despite growing under poorer nutrient conditions. Greater leaf N in pioneer mangroves coincided with their special root structure (e.g., high porosity together with a thin lignified/suberized exodermis) and powerful ROL. An interesting positive relation was observed between ROL and leaf N in mangroves. Moreover, rhizo-box data further showed that soil nitrification was also strongly correlated with ROL. A. marina, which had the highest ROL among the three mangrove species studied, consistently possessed the highest levels of NO3−, nitrification and ammonia-oxidizing bacteria and archaea gene copies in the rhizosphere. Besides, both NO3− and NH4+ influxes were found to be higher in the roots of A. marina when compared to those of K. obovata and R. stylosa. In summary, greater N acquisition by pioneer mangroves such as A. marina was strongly correlated with ROL which would regulate N transformation and translocation at the root-soil interface. The implications of this study may be significant in mangrove nutrition and the mechanisms involved in mangrove zonation.
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Yin, Bei, David Crowley, Gerd Sparovek, Wanderley Jose De Melo y James Borneman. "Bacterial Functional Redundancy along a Soil Reclamation Gradient". Applied and Environmental Microbiology 66, n.º 10 (1 de octubre de 2000): 4361–65. http://dx.doi.org/10.1128/aem.66.10.4361-4365.2000.
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ABSTRACT A strategy to measure bacterial functional redundancy was developed and tested with soils collected along a soil reclamation gradient by determining the richness and diversity of bacterial groups capable of in situ growth on selected carbon substrates. Soil cores were collected from four sites along a transect from the Jamari tin mine site in the Jamari National Forest, Rondonia, RO, Brazil: denuded mine spoil, soil from below the canopy of invading pioneer trees, revegetated soil under new growth on the forest edge, and the forest floor of an adjacent preserved forest. Bacterial population responses were analyzed by amending these soil samples with individual carbon substrates in the presence of bromodeoxyuridine (BrdU). BrdU-labeled DNA was then subjected to a 16S-23S rRNA intergenic analysis to depict the actively growing bacteria from each site. The number and diversity of bacterial groups responding to four carbon substrates (l-serine, l-threonine, sodium citrate, and α-lactose hydrate) increased along the reclamation-vegetation gradient such that the preserved forest soil samples contained the highest functional redundancy for each substrate. These data suggest that bacterial functional redundancy increases in relation to the regrowth of plant communities and may therefore represent an important aspect of the restoration of soil biological functionality to reclaimed mine spoils. They also suggest that bacterial functional redundancy may be a useful indicator of soil quality and ecosystem functioning.
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Zu, Lei, Guanghui Zhou, Fayu Long, Lipeng Zang, Danmei Chen, Guangqi Zhang, Mingzhen Sui, Yuejun He y Qingfu Liu. "Stochastic Processes Dominate Soil Microbial Community Assembly during the Restoration of Degraded Karst Forests". Forests 15, n.º 4 (25 de marzo de 2024): 594. http://dx.doi.org/10.3390/f15040594.
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The mechanisms underpinning the soil microbial community assembly are important, particularly in the fragile karst forest ecosystem. Despite such significance, relevant topics remain limited. We investigated a typical karst area, the Maolan National Nature Reserve in China. For this purpose, 30 forest dynamics plots were established on three restoration gradients in degraded karst forests, namely shrub, pioneer tree, and climax communities. Using vegetation surveys, we explored the diversity patterns, driving factors, and community assembly of the soil microbial communities during the restoration of degraded karst forest ecosystems. In addition, the soil physicochemical properties and macrogenomic sequencing data were examined. One-way analysis of variance and principal coordinates analysis showed no significant changes in soil microbial α-diversity during restoration, and the opposite pattern was observed for β-diversity. Variation partitioning analysis revealed that the combined effect of both soil microbial β-diversity and soil was significant (28% and 32% for bacteria and fungi, respectively). Pearson correlation analyses showed that plant species diversity and soil multifunctionality correlated significantly with soil microbial β-diversity. In contrast, the direct effect of plants was smaller (2% and 3% for bacteria and fungi, respectively). According to the dispersal–niche continuum index, stochastic processes were responsible for the assembly of the bacterial and fungal soil microbial communities. During restoration, the dominant influence of stochastic effects on the assembly of bacterial communities intensified. In contrast, the reverse tendency was observed in soil fungi. The investigation of the diversity pattern of soil microbial communities and their assembly can provide theoretical references for the restoration of degraded ecosystems.
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Jasim Al-Adool, Raafat, Suhad Muwafaq Hamdoon y Heba Faiz Hamodat. "Scardovia wiggsiae as Recent Player in Caries Process: a Review". Mustansiria Dental Journal 19, n.º 1 (24 de enero de 2024): 117–23. http://dx.doi.org/10.32828/mdj.v19i1.998.
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Aims: Oral cavity is attacked by many infectious agents that invade tooth, periodontium and tongue. Dental caries which is the most common oral disease, can caused by the reaction between tooth structure, oral bacteria and fermentable carbohydrates. Most of caries microbial researches considered Streptococcus mutans and lactobacilli as majors caries-associated players. The discovery of Scardovia wiggsiae in 2011 had highlighted the possible occurrence of dental decay in absence of both Streptococcus mutans and lactobacilli in addition to other oral diseases. This review focused on taxonomy, acidogenicity, normal habitat and the important roles of newly S.wiggsiae as the pioneer bacteria for initiation and progression of caries process.
Methods: The database was focused on articles published till 2022 for the topics oral diseases, dental caries, Scardovia wiggsiae and microbiology of dental caries
Conclusions: Scardovia wiggsiae can to be considered as a potential risk indicator for caries prediction in a given population.
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Sunarno, Ning, Fajri Hamdani y Viana Anantasiska. "Philips Lamp Product Innovation into UV-C Disinfectant Desk Lamp to Improve The Company's Competitiveness during The Covid-19 Pandemic". Jurnal Manajemen Bisnis 18, n.º 1 (30 de enero de 2021): 35–42. http://dx.doi.org/10.38043/jmb.v18i1.2772.
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The pandemic period is the reason for the company to set up an innovating strategy after conducting a series of research and product development. The purpose of Philips Company is to innovate not only to maintain the sustainability of product livecycle, but also to meet consumer needs for disinfectant tools by not leaving brand image in the pioneer of lighting products. Product innovation is done by designing products that effectively disable viruses, bacteria, fungi, and spores, in minutes. Consumer objectivity in deciding a product purchase due to the advantages of modern product design, energy saving, simple and put forward the ethics of environmentally friendly products.