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Journal articles on the topic "Bacterial hormones"
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Chetverikov, Sergey, Lidiya Vysotskaya, Elena Kuzina, Tatiana Arkhipova, Margarita Bakaeva, Gulnaz Rafikova, Tatiana Korshunova, Darya Chetverikova, Gaisar Hkudaygulov, and Guzel Kudoyarova. "Effects of Association of Barley Plants with Hydrocarbon-Degrading Bacteria on the Content of Soluble Organic Compounds in Clean and Oil-Contaminated Sand." Plants 10, no. 5 (May 13, 2021): 975. http://dx.doi.org/10.3390/plants10050975.
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Plant-bacteria consortia are more effective in bioremediation of petroleum contaminated soil than when either organism is used individually. The reason for this is that plant root exudates promote growth and activity of oil degrading bacteria. However, insufficient attention has been paid to the ability of bacteria to influence root exudation. Therefore, the influence of barley plants and/or bacterial inoculation (Pseudomonas hunanensis IB C7 and Enterobacter sp. UOM 3) on the content of organic acids, sugars and plant hormones in the eluate from clean and oil-polluted sand was studied separately or in combination. These strains are capable of oxidizing hydrocarbons and synthesizing auxins. Concentrations of organic acids and sugars were determined using capillary electrophoresis, and hormones by enzyme-linked immunosorbent assays. In the absence of plants, no sugars were detected in the sand, confirming that root exudates are their main source. Introducing bacteria into the sand increased total contents of organic compounds both in the presence and absence of oil. This increase could be related to the increase in auxin amounts in the sand eluate, as well as in plants. The results indicate that bacteria are able to increase the level of root exudation. Since auxins can promote root exudation, bacterial production of this hormone is likely responsible for increased concentrations of soluble organic compounds in the sand. Bacterial mediation of root exudation by affecting plant hormonal status should be considered when choosing microorganisms for phytoremediation.
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Taylor-Robinson, David. "Hormones in bacterial vaginosis." International Journal of STD & AIDS 19, no. 1 (January 2008): 67. http://dx.doi.org/10.1258/ijsa.2007.005700.
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García-Gómez, Elizabeth, Bertha González-Pedrajo, and Ignacio Camacho-Arroyo. "Role of Sex Steroid Hormones in Bacterial-Host Interactions." BioMed Research International 2013 (2013): 1–10. http://dx.doi.org/10.1155/2013/928290.
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Sex steroid hormones play important physiological roles in reproductive and nonreproductive tissues, including immune cells. These hormones exert their functions by binding to either specific intracellular receptors that act as ligand-dependent transcription factors or membrane receptors that stimulate several signal transduction pathways. The elevated susceptibility of males to bacterial infections can be related to the usually lower immune responses presented in males as compared to females. This dimorphic sex difference is mainly due to the differential modulation of the immune system by sex steroid hormones through the control of proinflammatory and anti-inflammatory cytokines expression, as well as Toll-like receptors (TLRs) expression and antibody production. Besides, sex hormones can also affect the metabolism, growth, or virulence of pathogenic bacteria. In turn, pathogenic, microbiota, and environmental bacteria are able to metabolize and degrade steroid hormones and their related compounds. All these data suggest that sex steroid hormones play a key role in the modulation of bacterial-host interactions.
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Harutyunyan, K. R., K. V. Melkumyan, H. T. Abrahamyam, S. H. Adamyan, D. H. Khudaverdyan, and A. S. Ter-Markosyan. "Calcium-regulating hormonal system in cardiac functional activity." NEW ARMENIAN MEDICAL JOURNAL, no. 4 (2022): 54–63. http://dx.doi.org/10.56936/18290825-2022.16.4-54.
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The variance of calcium homeostasis is known as a risk factor for the development of heart failure. A study of calcium-regulating hormones is a crucial element to understand underlying pathophysiological mechanisms of heart failure. Pro-inflammatory factors, released during mechanical, hypoxic or bacterial damage of myocardial cells, lead to an imbalance of calcium and disrupt to heart function. The investigation of mentioned factors influence mechanism on the heart, is an urgent solution for preventing the development of heart failure. Present study aimed to reveal the role of calcium-regulating hormones in heart functional activity and their possible involvement in the development of heart failure. The pharmacological analysis of the action mechanism of bacterial lipopolysaccharides on heart functional activity was carried out using a calcium channel blocker. The concentrations of calcium-regulating hormones in blood serum in patients suffering from heart failure was determined by immunoassay enzyme method, and ionized calcium and inorganic phosphate concentrations - by spectrophotometric method. The photoelectrical method was used to determine the direct effect of calcium-regulating hormones and possible calcium-dependent action mechanism of bacterial lipopolysaccharides on the isolated frog’s heart. Clinical findings show that chronic heart failure is accompanied by shifts in the calcium-regulating hormonal system and blood electrolyte balance. In vitro experiments on isolated frog hearts have shown the potentiating effect of parathyroid hormone, its related protein, calcitonin, and vitamin D3 on myocardial contractility. It has been shown, that bacterial lipopolysaccharides suppress the contractile and rhythmogenic functions of the myocardium, and their action can be mediated through a calcium-dependent mechanism. The increase of parathyroid hormone in chronic heart failure has a protective significance aimed at maintaining the contractile ability of a weakened myocardium and preserving cardiac output. Bacterial lipopolysaccharides are able to suppress functional activity of the heart by calcium-dependent mechanism.
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Lesouhaitier, Olivier, Thomas Clamens, Thibaut Rosay, Florie Desriac, Mélissande Louis, Sophie Rodrigues, Andrei Gannesen, et al. "Host Peptidic Hormones Affecting Bacterial Biofilm Formation and Virulence." Journal of Innate Immunity 11, no. 3 (November 5, 2018): 227–41. http://dx.doi.org/10.1159/000493926.
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Bacterial biofilms constitute a critical problem in hospitals, especially in resuscitation units or for immunocompromised patients, since bacteria embedded in their own matrix are not only protected against antibiotics but also develop resistant variant strains. In the last decade, an original approach to prevent biofilm formation has consisted of studying the antibacterial potential of host communication molecules. Thus, some of these compounds have been identified for their ability to modify the biofilm formation of both Gram-negative and Gram-positive bacteria. In addition to their effect on biofilm production, a detailed study of the mechanism of action of these human hormones on bacterial physiology has allowed the identification of new bacterial pathways involved in biofilm formation. In this review, we focus on the impact of neuropeptidic hormones on bacteria, address some future therapeutic issues, and provide a new view of inter-kingdom communication.
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Hanafi, Ahmad, Susiana Purwantisari, and Budi Raharjo. "Uji Potensi Bakteri Endofit Kitinolitik Tanaman Padi (Oryza sativa L.) Sebagai Penghasil Hormon IAA (Indole Acetic Acid)." Bioma : Berkala Ilmiah Biologi 19, no. 1 (September 8, 2017): 76. http://dx.doi.org/10.14710/bioma.19.1.76-82.
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IAA (Indole Acetic Acid) is a hormone in plants that was role in the cleavage of roots, inhibits the growth of side shoots, stimulate cell division and the formation of xylem and phloem tissue. This study aimed to test the potential of endophytic bacteria chitinolytic rice crop as hormone-producing IAA. This study uses 9 isolates of endophytic bacteria chitinolytic rice plants in isolation during practical work. The experiment consisted of 15 treatments and 3 replications. This study uses a randomized block design. The treatments tryptophan concentration combined with a variation pH, the endophytic bacteria grown on media chitinolytic tryptophan concentration of 0 mg/L, 102 mg/L, 204 mg/L, 306 mg/L and 408 mg/L are combined with pH 5, 7 and 9. the treatment was observed for 48 hours and observation once every 3 hours. The measured variable is the result of the production of IAA hormone with the treatment combination of tryptophan with pH. IAA hormone outcome data were analyzed using Analysis of Variance Univariates at level of 95%. IAA hormone qualitative test results showed positive results in bacterial isolates KA12, KA11 and KB24. IAA hormone quantitative results of bacterial isolates producing IAA hormone KA12 high of 2,03 mg/L in the combination treatment of tryptophan 408 mg/L at pH 7 at 24 hours incubation. KA12 bacterial isolates are endophytic bacteria chitinolytic potential to produce hormones IAA, yet the results of data analysis showed that each treatment combination with pH tryptophan to IAA production were not significantly different. Keywords: hormone IAA, chitinolytic endophytic bacteria, tryptophan, pH
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Sandrini, Sara M., Raminder Shergill, Jonathan Woodward, Remya Muralikuttan, Richard D. Haigh, Mark Lyte, and Primrose P. Freestone. "Elucidation of the Mechanism by Which Catecholamine Stress Hormones Liberate Iron from the Innate Immune Defense Proteins Transferrin and Lactoferrin." Journal of Bacteriology 192, no. 2 (October 9, 2009): 587–94. http://dx.doi.org/10.1128/jb.01028-09.
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ABSTRACT The ability of catecholamine stress hormones and inotropes to stimulate the growth of infectious bacteria is now well established. A major element of the growth induction process has been shown to involve the catecholamines binding to the high-affinity ferric-iron-binding proteins transferrin (Tf) and lactoferrin, which then enables bacterial acquisition of normally inaccessible sequestered host iron. The nature of the mechanism(s) by which the stress hormones perturb iron binding of these key innate immune defense proteins has not been fully elucidated. The present study employed electron paramagnetic resonance spectroscopy and chemical iron-binding analyses to demonstrate that catecholamine stress hormones form direct complexes with the ferric iron within transferrin and lactoferrin. Moreover, these complexes were shown to result in the reduction of Fe(III) to Fe(II) and the loss of protein-complexed iron. The use of bacterial ferric iron uptake mutants further showed that both the Fe(II) and Fe(III) released from the Tf could be directly used as bacterial nutrient sources. We also analyzed the transferrin-catecholamine interactions in human serum and found that therapeutically relevant concentrations of stress hormones and inotropes could directly affect the iron binding of serum-transferrin so that the normally highly bacteriostatic tissue fluid became significantly more supportive of the growth of bacteria. The relevance of these catecholamine-transferrin/lactoferrin interactions to the infectious disease process is considered.
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Gabor, Caitlin R., Melissa Villatoro-Castañeda, Camila Carlos-Shanley, Nikolett Ujhegyi, and Veronika Bókony. "Gut Bacterial Communities Vary across Habitats and Their Diversity Increases with Increasing Glucocorticoids in Toad Tadpoles." Diversity 15, no. 1 (December 23, 2022): 23. http://dx.doi.org/10.3390/d15010023.
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The gut microbiome is important for host health and can be influenced by environmental and hormonal changes. We studied the interactions between anthropogenic land use, glucocorticoid hormones, and gut bacterial communities in common toads (Bufo bufo). We sampled tadpoles from ponds of three habitat types (natural, agricultural, and urban ponds), examined gut microbiome composition using amplicon sequencing of the 16S rRNA gene, and measured the associated stress physiology using water-borne hormones. Tadpoles from different habitat types significantly differed in bacterial composition. However, bacterial richness, Shannon diversity, and Firmicutes to Bacteroidota ratio did not vary with habitat type. In contrast with other studies, we found a positive correlation between baseline corticosterone release rate and bacterial diversity. Stress response and negative feedback were not significantly correlated with bacterial diversity. These results suggest that, despite alterations in the composition of intestinal bacterial communities due to land-use change, common toad tadpoles in anthropogenic habitats may maintain their physiological health in terms of the “gut-brain axis”.
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Almalki, Ahmad J., Tarek S. Ibrahim, Sameh S. Elhady, Wael A. H. Hegazy, and Khaled M. Darwish. "Computational and Biological Evaluation of β-Adrenoreceptor Blockers as Promising Bacterial Anti-Virulence Agents." Pharmaceuticals 15, no. 2 (January 18, 2022): 110. http://dx.doi.org/10.3390/ph15020110.
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Bacterial resistance to antibiotics is an increasing public health threat as it has the potential to affect people at any stage of life, as well as veterinary. Various approaches have been proposed to counteract the bacterial resistance development. Tackling bacterial virulence is one of the most promising approaches that confer several merits. The bacterial virulence is mainly regulated by a communication system known as quorum sensing (QS) system. Meanwhile, bacteria can sense the adrenergic hormones and eavesdrops on the host cells to establish their infection, adrenergic hormones were shown to enhance the bacterial virulence. In this study, β-adrenoreceptor blockers were proposed not only to stop bacterial espionage on our cells but also as inhibitors to the bacterial QS systems. In this context, a detailed in silico study has been conducted to evaluate the affinities of twenty-two β-blockers to compete on different structural QS receptors. Among the best docked and thermodynamically stable β-blockers; atenolol, esmolol, and metoprolol were subjected to further in vitro and in vivo investigation to evaluate their anti-QS activities against Chromobacterium violaceum, Pseudomonas aeruginosa and Salmonella typhimurium. The three tested β-blockers decreased the production of QS-controlled C. violaceum, and the formation of biofilm by P. aeruginosa and S. typhimurium. Additionally, the tested β-blockers down-regulated the P. aeruginosa QS-encoding genes and S. typhimurium sensor kinase encoding genes. Furthermore, metoprolol protected mice against P. aeruginosa and S. typhimurium. Conclusively, these investigated β-blockers are promising anti-virulence agents antagonizing adrenergic hormones induced virulence, preventing bacterial espionage, and blocking bacterial QS systems.
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Del Rio, Laura, Antonio Murcia-Belmonte, Antonio Julián Buendía, Jose Antonio Navarro, Nieves Ortega, Daniel Alvarez, Jesús Salinas, and María Rosa Caro. "Effect of Female Sex Hormones on the Immune Response against Chlamydia abortus and on Protection Conferred by an Inactivated Experimental Vaccine in a Mouse Model." Pathogens 11, no. 1 (January 14, 2022): 93. http://dx.doi.org/10.3390/pathogens11010093.
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Mice are valuable models extensively used to test vaccine candidates against Chlamydia abortus and to clarify immunopathological mechanisms of the bacteria. As this pathogen has the ability to reactivate during pregnancy, it is important to deepen the knowledge and understanding of some of the effects of female hormones on immunity and vaccination. This study is aimed at describing the role of sex hormones in the pathology of OEA during chlamydial clearance using ovariectomised mice and also gaining an understanding of how 17β-oestradiol or progesterone may impact the effectiveness of vaccination. Animals were treated with sex hormones and infected with C. abortus, and the kinetics of infection and immune response were analysed by means of bacterial isolation, histopathology, and immunohistochemistry. In a second phase of the study, protection conferred by an experimental vaccine after hormone treatment was assessed. Oestradiol showed a stimulatory effect on the immune response during infection, with a more efficient recruitment of macrophages and T-cells at the infection site. Furthermore, after vaccination, oestradiol-treated animals showed a stronger protection against infection, indicating that this hormone has a positive effect, stimulating a specific memory response to the pathogen.
Dissertations / Theses on the topic "Bacterial hormones"
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Frankenfeld, Cara L. "Hormone status postmenopause : colonic bacterial effects /." Thesis, Connect to this title online; UW restricted, 2003. http://hdl.handle.net/1773/10854.
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Sanchez, Barrios Andrea Marisa. "BACTERIAL INOCULANTS, ENDOPHYTIC BACTERIA AND THEIR INFLUENCE ON NICOTIANA PHYSIOLOGY, DEVELOPMENT AND MICROBIOME." UKnowledge, 2018. https://uknowledge.uky.edu/pss_etds/101.
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Soil and root microbial communities have been studied for decades, and the incorporation of high-throughput techniques and analysis has allowed the identification of endophytic/non-culturable organisms. This has helped characterize and establish the core microbiome of many model plant species which include underground and aboveground organs. Unfortunately, the information obtained from some of these model plants is not always transferable to other agronomic species. In this project, we decided to study the microbiome of the Nicotiana genus because of its importance in plant physiological and plant-microbe interactions studies. The data obtained was used as baseline information that allowed us to better understand the effect of microbial inoculums on the assembly of the microbiome of the plant. We analyzed 16s rRNA amplicons to survey the microbiome in different plant organs and rhizosphere from four different species. Bacterial strains evaluated were screened for a consistent reduction or improvement in plant growth. Four bacterial strains were tested and used as seed inoculum (Lf-Lysinobacillus fusisormis, Ms –Micrococcus sp., Bs–Bacillus sp., Bc–Bacillus cereus). Bs and Bc inoculants caused plant growth promotion, and in contrast Ms caused retarded growth, while Lf acted as a neutral or non-inducing phenotype strain. Data supported that microbial inoculum used as seed treatment caused systemic changes in the host plant microbiome. Functionality of the inoculum was studied and the response in plant growth was linked to hormonal changes (evaluated in the plant and in the bacterial strains). Gene expression analysis using a genome-scale approach revealed that genes that could possibly be involved in stress response are down-regulated for Bc and Bs treatments and up-regulated for Ms. Flexibility variability of the inoculum was also evaluated to have a better understanding of the main factors involved in the promotion or suppression of growth, and possibly its effect in following generations. In summary, the findings of this project support that the plant functional microbiome responds to exogenous stimulation from abiotic and biotic factors by adapting endogenous hormone responses.
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Stewart, Amanda B. "Steroid hormone enrichment of brine shrimp (Artemia salina) nauplii Factors associated with acute bacterial infection that limit fertility /." Morgantown, W. Va. : [West Virginia University Libraries], 1999. http://etd.wvu.edu/templates/showETD.cfm?recnum=1138.
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Sharaff, Fathima Farveen Casim Sahib Mohammed. "The role of catecholamine stress hormones and inotropes in the promotion of bacterial growth, virulence and biofilm formation." Thesis, University of Leicester, 2012. http://hdl.handle.net/2381/11044.
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Bacteria in most environments exist and grow in association with surfaces, leading to formation of biofilms. In the medical context, biofilms are particularly significant for human health because of their high resistance to antimicrobial and immune system attack. In the health care setting biofilms associated with indwelling devices such as intravenous catheters and endotracheal tubes is a major clinical problem. It has been shown in previous reports that catecholamine stress hormones such as epinephrine, norepinephrine and structurally similar inotrope drugs used to treat heart and kidney problems in seriously-ill patients, are able to promote growth and virulence of certain bacteria. In this thesis, the role of catecholamine inotropes and stress hormones as an environmental factor for the induction of biofilm formation by infectious bacteria relevant to medical devices is considered. In vitro phenotypic characterisation was investigated by mainly using microbiological techniques, microscopy and proteomic analysis. The first section of this thesis shows how clinically attainable levels of catecholamine inotropes stimulated Pseudomonas aeruginosa growth and biofilm formation. The mechanism by which growth stimulation occurs was found to be via delivery of iron from the serum Fe-binding transferrin. P. aeruginosa growth, biofilm formation and motility were all significantly enhanced by catecholamine inotropes (P<0.05). Inotropes may be a risk factor for ventilator associated pneumonia as they stimulated biofilm formation on endotracheal tubing. In the second section which focuses on Escherichia coli and Salmonella Typhimurium, it was found that catecholamine stress hormone effect on growth, motility and biofilm formation was independent of the putative QseC and QseE catecholamine sensing receptors. In the third section, factors related to catecholamines inotropes Staphylococcus epidermidis biofilm stimulation were considered. Collectively, these findings show that levels of catecholamine inotropes found within critically ill patients can promote bacterial biofilm formation, and so contribute to bacterial pathogenesis within the hospital setting.
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McAdory, Louis E. "CHEMICAL SYNTHESIS, BACTERIAL EXPRESSION, AND CHARACTERIZATION OF PRO-GNRH/GAP, A PRECURSOR PROTEIN OF TWO BIOLOGICAL ACTIVE PEPTIDE HORMONES." VCU Scholars Compass, 1998. https://scholarscompass.vcu.edu/etd/5233.
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Two biologically active peptides, gonadotropin releasing hormone (GnRH) and GnRH associated peptide (GAP) are both derived from a common prohormone precursor protein, pro-GnRH/GAP. Both peptides are cosecreted from hypothalamic neurosecretory granules and are involved in the regulation of mammalian reproduction. A calcium dependent, neutral pH serine protease discovered in this laboratory, GAP-releasing enzyme, is the most likely processing enzyme of pro-GnRH/GAP. GAP-releasing enzyme is immunologically related to PC1/3, a member of the prohormone convertase (PC) class of processing endoproteinases.
GAP-releasing enzyme recognizes the eight residue processing site within pro-GnRH/GAP, G6LRPGGKR13, and correctly cleaves the R13-D14 bond to yield bioactive GAP and a three residue extension of GnRH. We and others have postulated that the recognition site for GAP-releasing enzyme forms a defined structural element at the surface of the substrate protein and that this structural element helps mediate limited endoproteolysis.
In the work reported here, hundred mg quantities of pro-GnRH/GAP were prepared by novel methods of both chemical synthesis and bacterial expression. Large amounts of pure protein are required for enzymatic and biophysical studies of pro-GnRH/GAP, which are intended to establish whether or not the processing site within the prohormone exists as a defined structural element that plays a central role in endoproteolytic processing. Synthetic pro-GnRH/GAP was prepared in high yield but proved difficult to purify to homogeneity. Recombinant pro-GnRH/GAP was prepared in sufficient yield and purity to perform all subsequent experiments.
An immunoassay was developed against a processing site epitope within pro-GnRH/GAP. Both synthetic and recombinant pro-GnRH/GAP proteins are immunoreactive, consistent with the idea that the epitope, and, thus, the processing site, is located on the surface of the molecule. Proteolysis of synthetic or recombinant pro-GhRH/GAP by trypsin or kallikrein caused immediate loss of immunoactivity, showing that the processing site is susceptible to proteolysis and that the integrity of the processing site is required for immunoactivity. One of the kallikreih hydrolytic products was identified as GAP. Therefore, kallikrein cleaves at the R13-D14 bond.
The intrinsic fluorescence yield of the Trp residue near the processing site region of pro-GhRH/GAP is sensitive to changes in pH, but not to changes in ionic strength or calcium concentration; its fluorescence yield is maximal at neutral pH. This suggests that the processing site displays maximum structure at neutral pH. This finding is coincident with the fact that GAP-releasing enzyme is optimally active at neutral pH. However, the relative contribution of secondary structural elements, as discerned by circular dichroism, remains constant over the range of pH 5.2-10.7. Only at pH
Thermal denaturation of pro-GnRH/GAP follows a simple two-state transition at neutral pH, as assessed by differential scanning calorimetry. This shows that pro-GnRH/GAP assumes a protein—like tertiary structure at neutral pH. 1D NMR data obtained at variable pH showed changes in resonance position and spectral resolution which are consistent with pH mediated conformational change and with the assumption of organized structure at neutral pH. However, the lack of through space correlations in the 2D NOESY experiment indicates that determination of the three-dimensional structure of pro-GnRH/GAP at neutral pH may be problematic.
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Zhao, Huifang. "Improved Methods of Sepsis Case Identification and the Effects of Treatment with Low Dose Steroids: A Dissertation." eScholarship@UMMS, 2011. https://escholarship.umassmed.edu/gsbs_diss/529.
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Sepsis is the leading cause of death among critically ill patients and the 10th most common cause of death overall in the United States. The mortality rates increase with severity of the disease, ranging from 15% for sepsis to 60% for septic shock. Patient with sepsis can present varied clinical symptoms depending on the personal predisposition, causal microorganism, organ system involved, and disease severity. To facilitate sepsis diagnosis, the first sepsis consensus definitions was published in 1991 and then updated in 2001. Early recognition of a sepsis patient followed with timely and appropriate treatment and management strategies have been shown to significantly reduce sepsis-related mortality, and allows care to be provided at lower costs. Despite the rapid progress in the knowledge of pathophysiological mechanisms of sepsis and its treatment in the last two decades, identifying patient with sepsis and therapeutic approaches to sepsis and its complications remains challenging to critical care clinicians. Hence, the objectives of this thesis were to 1) evaluate the test characteristics of the two sepsis consensus definitions and delineate the differences in patient profile among patients meeting or not meeting sepsis definitions; 2) determine the relationship between the changes in several physiological parameters before sepsis onset and sepsis, and to determine whether these parameters could be used to identify sepsis in critically ill adults; 3) evaluate the effect of corticosteroids therapy on patient mortality.
Data used in this thesis were prospectively collected from an electronic medical record system for all the adult patients admitted into the seven critical care units (ICUs) in a tertiary medical center. Besides analyzing data at the ICU stay level, we investigated patient information in various time frames, including 24-hour, 12-hour, and 6-hour time windows.
In the first study of this thesis, the 1991 sepsis definition was found to have a high sensitivity of 94.6%, but a low specificity of 61.0%. The 2001 sepsis definition had a slightly increased sensitivity but a decreased specificity, which was 96.9% and 58.3%, respectively. The areas under the ROC curve for the two consensus definitions were similar, but less than optimal. The sensitivity and area under the ROC curve of both definitions were lower at the 24-hour time window level than those of the unit stay level, though the specificity increased slightly. At the time window level, the 1991 definitions performed slightly better than the 2001 definition.
In the second study, minimum systolic blood pressure performed the best, followed by maximum respiratory rate in discriminating sepsis patients from SIRS patients. Maximum heart rate and maximum respiratory rate can differentiate sepsis patients from non-SIRS patients fairly well. The area under ROC of the combination of five physiological parameters was 0.74 and 0.90 for comparing sepsis to non-infectious SIRS patients and comparing sepsis to non-SIRS patients, respectively. Parameters typically performed better in 24-hour windows compared to 6-hour or 12-hour windows.
In the third study, significantly increased hospital mortality and ICU mortality were observed in the group treated with low-dose corticosteroids than the control group based on the propensity score matched comparisons, and multivariate logistic regression analyses after adjustment for propensity score alone, covariates, or propensity score (in deciles) and covariates.
This thesis advances the existing knowledge by systemically evaluating the test characteristics for the 1991 and 2001 sepsis consensus definitions, delineating physiological signs and symptoms of deterioration in the preceding 24 hours prior to sepsis onset, assessing the prediction performances of single or combined physiological parameters, and examining the use of corticosteroids treatment and survival among septic shock patients. In addition, this thesis sets an innovative example on how to use data from electronic medical records as these surveillance systems are becoming increasingly popular. The results of these studies suggest that a more parsimonious set of definitional criteria for sepsis diagnosis are needed to improve sepsis case identification. In addition, continuously monitored physiological parameters could help to identify patients who show signs of deterioration prior to developing sepsis. Last but not least, caution should be used when considering a recommendation on the use of low dose corticosteroids in clinical practice guidelines for the management of sepsis.
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Abidov, Amir. "Effects of Hormone Crosstalk on Endophytic Bacterial Communities." Thesis, The University of Arizona, 2015. http://hdl.handle.net/10150/578977.
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The plant hormones salicylic and jasmonic acid (SA and JA, respectively) both play a crucial role in the induction of plant defense system pathways and long-term pathogen resistance. Plants, which do not have an active cellular immune system like animals, instead rely on the release of specific molecules to mediate defense. In general, the SA pathway is activated by biotrophic pathogens and primarily induces antimicrobial responses, while JA is activated by necrotrophic pathogens and herbivory, and induces separate chemical responses. SA and JA are reciprocally antagonistic: activation of one pathway inhibits activation of the other. Here we explore how SA-JA inhibitory crosstalk is used by pathogens or herbivores to combat plant defense. We study the effects of hormone crosstalk on bacterial growth in two plant models: Cardamine cordifolia and Arabidopsis thaliana, which we treated to induce defense pathways. These plants were inoculated with endophytic bacteria isolated from field C. cordifolia plants, and the effects of hormone treatment on bacterial growth rates were measured. We show that JA-induced defenses, which are commonly associated with necrotrophic pathogens, affect varied biotrophic Pseudomonas strains both positively and negatively. Notably, we show that JA-induce defenses affect wild P. fluorescens strains more negatively than SA-defenses.
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Fahrbach, Michael. "Anaerobic degradation of steroid hormones by novel denitrifying bacteria." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=982986769.
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Reiske, Lena [Verfasser], and Volker [Akademischer Betreuer] Stefanski. "Stress hormone-induced immunomodulation and interplay between immune cells and bacteria in response to stress hormones in domestic pigs / Lena Reiske ; Betreuer: Volker Stefanski." Hohenheim : Kommunikations-, Informations- und Medienzentrum der Universität Hohenheim, 2020. http://d-nb.info/1223023249/34.
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Geng, Xueqing. "The Bacterial Toxin COR, a Hormone Mimic, Modulates Plant Hormone Signaling and Regulates Secondary Metabolism in Arabidopsis." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1325059787.
Full textBooks on the topic "Bacterial hormones"
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Bacterial and bacteriophage genetics. 4th ed. New York: Springer, 2000.
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Bacterial and bacteriophage genetics. 3rd ed. New York: Springer-Verlag, 1994.
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Bacterial and bacteriophage genetics: An introduction. 2nd ed. New York: Springer-Verlag, 1988.
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Lee, Kleinman Daniel, Kinchy Abby J, and Handelsman Jo, eds. Controversies in science and technology: From maize to menopause. Madison, Wis: University of Wisconsin Press, 2005.
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BACTERIAL AND BACTERIOPHAGE GENETICS. Springer Verlag, 2000.
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Bacterial and Bacteriophage Genetics. Springer, 2005.
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Birge, Edward A. Bacterial and Bacteriophage Genetics. Springer New York, 2013.
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Birge, Edward A. Bacterial and Bacteriophage Genetics. Springer, 2013.
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Birge, Edward A. Bacterial and Bacteriophage Genetics. Springer London, Limited, 2006.
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Birge, Edward A. Bacterial and Bacteriophage Genetics. Springer, 2013.
Find full textBook chapters on the topic "Bacterial hormones"
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Rettew, Jennifer A., Ian Marriott, and Yvette M. Huet. "Sex Differences in Innate Immune Responses to Bacterial Pathogens." In Sex Hormones and Immunity to Infection, 123–46. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-02155-8_5.
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Karavolos, Michail H., and C. M. Anjam Khan. "Host Neuroendocrine Stress Hormones Driving Bacterial Behaviour and Virulence." In Heat Shock Proteins, 387–98. Dordrecht: Springer Netherlands, 2013. http://dx.doi.org/10.1007/978-94-007-6787-4_25.
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Rasul, Ghulam, M. Sajjad Mirza, Farooq Latif, and Kauser A. Malik. "Identification of plant growth hormones produced by bacterial isolates from rice, wheat and kallar grass." In Nitrogen Fixation with Non-Legumes, 25–37. Dordrecht: Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-011-5232-7_4.
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Long, D. A. "The Influence of the Thyroid Gland Upon Immune Responses of Different Species to Bacterial Infection." In Ciba Foundation Symposium - Regulation and Mode of Action of Thyroid Hormones (Colloquia on Endocrinology, Vol. 10), 287–304. Chichester, UK: John Wiley & Sons, Ltd., 2008. http://dx.doi.org/10.1002/9780470719022.ch19.
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Costantino, Paolo, Maura Cardarelli, Maria Luisa Mauro, and Laura Spano. "Role of Agrobacterium Rhizogenes Hormone Genes in the Induction of Hairy Root." In Plant Pathogenic Bacteria, 34–41. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-009-3555-6_5.
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Ben-Nathan, D., G. J. M. Maestroni, and A. Conti. "The Protective Effect of Melatonin in Viral and Bacterial Infections." In Frontiers of Hormone Research, 72–80. Basel: KARGER, 1997. http://dx.doi.org/10.1159/000060977.
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Duca, Frank, Philippe Gérard, Mihai Covasa, and Patricia Lepage. "Metabolic Interplay between Gut Bacteria and Their Host." In Frontiers of Hormone Research, 73–82. Basel: S. KARGER AG, 2014. http://dx.doi.org/10.1159/000358315.
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Jha, Chaitanya Kumar, and Meenu Saraf. "Hormonal Signaling by PGPR Improves Plant Health Under Stress Conditions." In Bacteria in Agrobiology: Stress Management, 119–40. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-662-45795-5_7.
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Sheehy, R. E., V. Ursin, S. Vanderpan, and W. R. Hiatt. "Expression of a Bacterial ACC Deaminase Gene in Tomato." In Cellular and Molecular Aspects of the Plant Hormone Ethylene, 106–10. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-017-1003-9_22.
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Romanov, Georgy A., and Sergey N. Lomin. "Hormone-Binding Assay Using Living Bacteria Expressing Eukaryotic Receptors." In Methods in Molecular Biology, 111–20. Totowa, NJ: Humana Press, 2008. http://dx.doi.org/10.1007/978-1-59745-477-3_10.
Full textConference papers on the topic "Bacterial hormones"
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Al-Asmar, Jawaher, Sara Rashwan, and Layla Kamareddine. "The use of Drosophila Melanogaster as a Model Organism to study the effect of Bacterial Infection on Host Survival and Metabolism." In Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2020. http://dx.doi.org/10.29117/quarfe.2020.0186.
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Enterobacteriaceae, a large family of facultative anaerobic bacteria, encloses a broad spectrum of bacterial species including Escherichia coli, Salmonella enterica, and Shigella sonnei, that produce enterotoxins and cause gastrointestinal tract diseases. While much is known about the regulation and function of enterotoxins within the intestine of the host; the lack of cheap, practical, and genetically tractable model organisms has restricted the investigation of others facets of this host-pathogen interaction. Our group, among others, has employed Drosophila melanogaster, as a model organism to shed more light on some aspects of host-pathogen interplays. In this project, we addressed the effect of Escherichia coli, Salmonella enterica, and Shigella sonnei infection on altering the metabolic homeostasis of the host. Drosophila melanogaster flies were orally infected with Escherichia coli, Salmonella enterica, or Shigella sonnei, a method that mimics the natural route used by enteric pathogens to gain access to the gastrointestinal tract in humans. The results of our study revealed that both Escherichia coli and Shigella sonnei pathogens were capable of colonizing the host gut, resulting in a reduction in the life span of the infected host. Escherichia coli and Shigella sonnei infected flies also exhibited altered metabolic profiles including lipid droplets deprivation from their fat body (normal lipid storage organ in flies), irregular accumulation of lipid droplets in their gut, and significant elevation of systemic glucose and triglyceride levels. These metabolic alterations could be mechanistically attributed to the differential down-regulation in the expression of metabolic peptide hormones (Allatostatin A, Diuretic hormone 31, and Tachykinin) detected in the gut of Escherichia coli and Shigella sonnei infected flies. Salmonella enterica; however, was unable to colonize the gut of the host; and therefore, Salmonella enterica infected flies exhibited a relatively normal metabolic status as that of non infected flies. Gaining a proper mechanistic understanding of infection-induced metabolic alterations helps in modulating the pathogenesis of gastrointestinal tract diseases in a host and opens up for promising therapeutic approaches for infection induced metabolic disorders
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Bakaeva, M. D., Li B. Vysotskaya, T. N. Arkhipova, E. V. Kuzina, S. P. Chetverikov, G. F. Rafikova, T. Yu Korshunova, O. N. Loginov, D. S. Veselov, and G. R. Kudoyarova. "The influence of plant growth stimulating bacteria on phytoremediation of oil-contaminated soils." In 2nd International Scientific Conference "Plants and Microbes: the Future of Biotechnology". PLAMIC2020 Organizing committee, 2020. http://dx.doi.org/10.28983/plamic2020.033.
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Arkhipova, T. N., E. V. Martynenko, L. Yu Kuzmina, and D. S. Veselov. "Comparison of the influence bacteria producing either auxin or cytokinin on growth and water relation of wheat plants under salinity." In 2nd International Scientific Conference "Plants and Microbes: the Future of Biotechnology". PLAMIC2020 Organizing committee, 2020. http://dx.doi.org/10.28983/plamic2020.027.
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Rhizobacteria reduced the negative effects of salinity on wheat plants. Similarities and differences in the effect of hormone-producing halotolerant bacteria on plant growth and water relations during salinity are discussed.
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Feoktistova, A. V., M. D. Timergalin, T. V. Rameev, and S. P. Chetverikov. "The role of auxin-producing bacteria in the formation of a growth response in wheat plants under herbicidal stress." In 2nd International Scientific Conference "Plants and Microbes: the Future of Biotechnology". PLAMIC2020 Organizing committee, 2020. http://dx.doi.org/10.28983/plamic2020.073.
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The paper presents the results of the effect of treatment with bacteria on the growth and hormonal balance of wheat plants with simultaneous exposure to the herbicide Chistalan. It is shown that herbicide stress is leveled by bacteria.
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Akhtyamova, Z. A. "Comparison of the reaction of barley plants to treatment with microorganisms producing auxins and cytokinins." In 2nd International Scientific Conference "Plants and Microbes: the Future of Biotechnology". PLAMIC2020 Organizing committee, 2020. http://dx.doi.org/10.28983/plamic2020.011.
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We studied the effect of bacterization of seedlings of barley plants with strains of hormone-producing bacteria B. subtilis IB-22 and P. mandelii IB-Ki14. The parameters of plant growth, as well as RWС and the content of chlorophyll in their leaves were estimated.
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Farah, Huda Mohamed, Muram Elmubarak Elamin, Rahaf Nader Nader Nader, Rana Said Alabsi, Salma Bouazza Bouabidi, Sara Elgaili Khogali Suleiman, Shahd Mohammad Nasr, Shouq Fahad Al-Rumaihi, Zain Zaki Zakaria, and Maha alasmakh Alasmakh. "Metagenomic Analysis of Oral Microbiome during pregnancy." In Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2021. http://dx.doi.org/10.29117/quarfe.2021.0135.
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Pregnancy is a dynamic physiological process associated with significant hormonal, immune and metabolic changes to support the growth and development of the fetus. Several studies have highlighted the role of gut microbiota during pregnancy1. The composition of gut microbiota changes dramatically during the course of pregnancy with an increase in Proteobacteria and Actinobacteria, a decline in butyrate-producing bacteria and a reduction in bacterial richness at the end of pregnancy2. These modifications were anticipated to favour the increased metabolic demand during pregnancy, which will, in turn, support healthy fetal growth3. Gut microbiota has also been suggested to contribute to weight gain during pregnancy via increased absorption of glucose and fatty acids, induction of catabolic pathways, increased fasting-induced adipocyte factor secretion, and stimulation of the immune system2, 4. The oral cavity houses the second most diverse microbiota after the gut harbouring over 700 species of bacteria. Oral microbiota plays a crucial role in maintaining oral homeostasis, protecting the oral cavity and preventing disease development5. Little is known about the role of the oral microbiome during pregnancy. One study examined changes in oral microbiota during pregnancy on Japanese women and found that the total viable microbial counts were higher during pregnancy, as were levels of the pathogenic bacteria Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and Candida6. Several studies have also found correlations between oral infections and pregnancy complications, further suggesting mechanisms connecting the oral microbiome with the state of pregnancy7. The Qatari Birth Cohort (QbiC) was successfully developed in July 2018 by Qatar Biobank. It is an epidemiological study that aims to assess the synergetic role of environmental exposure and genetic factors in the development of chronic disease. It monitors the health of women throughout their pregnancy and after birth. The present study is designed to explore changes in the salivary microbiome, using high throughput sequencing during pregnancy and to explore key microbial clades involved in pregnancy.
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Arkhipova, T. N., and E. V. Martynenko. "The effect of hormone producing bacteria on plant growth and stress tolerance." In IX Congress of society physiologists of plants of Russia "Plant physiology is the basis for creating plants of the future". Kazan University Press, 2019. http://dx.doi.org/10.26907/978-5-00130-204-9-2019-48.
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Kudoyarova, G. R., T. N. Arkhipova, D. S. Veselov, and L. B. Vysotskaya. "Hormonal balance of plants and its relationship with changes in plant growth and productivity under the influence of rhizospheric bacteria." In 2nd International Scientific Conference "Plants and Microbes: the Future of Biotechnology". PLAMIC2020 Organizing committee, 2020. http://dx.doi.org/10.28983/plamic2020.137.
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Here we analyze the dependence of the growth and water relations on the ability of bacteria to influence the content and distribution of abscisic acid (ABA) in plants under different growing conditions.
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Balle, Christina, Katie Lennard, Iyaloo Konstantinus, Shameem Jaumdally, Rachel Esra, Shaun Barnabas, Anna-Ursula Happel, et al. "P367 Hormonal contraception and risk of STIs and bacterial vaginosis in south african adolescents: a randomized trial." In Abstracts for the STI & HIV World Congress (Joint Meeting of the 23rd ISSTDR and 20th IUSTI), July 14–17, 2019, Vancouver, Canada. BMJ Publishing Group Ltd, 2019. http://dx.doi.org/10.1136/sextrans-2019-sti.469.
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Anugrah, Fauzi Akhbar, Rizal Fanany, Satrio Anggoro Putra, Rahmi Masita, and Desi Yulia Safitri. "Indole acetic acid (IAA) hormone production by endophytic bacteria isolate from Cinchona plant (Cinchona ledgerina Moens.) root." In INTERNATIONAL CONFERENCE ON LIFE SCIENCES AND TECHNOLOGY (ICoLiST 2020). AIP Publishing, 2021. http://dx.doi.org/10.1063/5.0052923.
Full textReports on the topic "Bacterial hormones"
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Alfano, James, Isaac Barash, Thomas Clemente, Paul E. Staswick, Guido Sessa, and Shulamit Manulis. Elucidating the Functions of Type III Effectors from Necrogenic and Tumorigenic Bacterial Pathogens. United States Department of Agriculture, January 2010. http://dx.doi.org/10.32747/2010.7592638.bard.
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Many phytopathogenic bacteria use a type III protein secretion system (T3SS) to inject type III effectors into plant cells. In the experiments supported by this one-year feasibility study we investigated type III effector function in plants by using two contrasting bacterial pathogens: Pseudomonas syringae pv. tomato, a necrotrophic pathogen and Pantoea agglomerans, a tumorigenic pathogen. The objectives are listed below along with our major conclusions, achievements, and implications for science and agriculture. Objective 1: Compare Pseudomonas syringae and Pantoea agglomerans type III effectors in established assays to test the extent that they can suppress innate immunity and incite tumorigenesis. We tested P. agglomerans type III effectors in several innate immunity suppression assays and in several instances these effectors were capable of suppressing plant immunity, outputs that are suppressed by P. syringae effectors. Interestingly, several P. syringae effectors were able to complement gall production to a P. agglomerans pthGmutant. These results suggest that even though the disease symptoms of these pathogens are dramatically different, their type III effectors may function similarly. Objective 2: Construct P. syringae mutants in different combinations of type III-related DNA clusters to reduce type III effector redundancy. To determine their involvement in pathogenicity we constructed mutants that lack individual and multiple type III-related DNA clusters using a Flprecombinase-mediated mutagenesis strategy. The majority of single effector mutants in DC3000 have weak pathogenicity phenotypes most likely due to functional redundancy of effectors. Supporting this idea, Poly-DNAcluster deletion mutants were more significantly reduced in their ability to cause disease. Because these mutants have less functional redundancy of type III effectors, they should help identify P. syringae and P. agglomerans effectors that contribute more significantly to virulence. Objective 3: Determine the extent that P. syringae and P. agglomerans type III effectors alter hormone levels in plants. Inhibition of auxin polar transport by 2,3,5-triiodobenzoic acid (TIBA) completely prevented gall formation by P. agglomerans pv. gypsophilae in gypsophila cuttings. This result supported the hypothesis that auxin and presumably cytokinins of plant origin, rather than the IAA and cytokinins secreted by the pathogen, are mandatory for gall formation. Transgenic tobacco with pthGshowed various phenotypic traits that suggest manipulation of auxin metabolism. Moreover, the auxin levels in pthGtransgenic tobacco lines was 2-4 times higher than the control plants. External addition of auxin or cytokinins could modify the gall size in gypsophila cuttings inoculated with pthGmutant (PagMx27), but not with other type III effectors. We are currently determining hormone levels in transgenic plants expressing different type III effectors. Objective 4: Determine whether the P. agglomerans effectors HsvG/B act as transcriptional activators in plants. The P. agglomerans type III effectors HsvG and HsvB localize to the nucleus of host and nonhost plants and act as transcription activators in yeast. Three sites of adjacent arginine and lysine in HsvG and HsvB were suspected to act as Nuclear localization signals (NLS) domains. A nuclear import assay indicated two of the three putative NLS domains were functional NLSs in yeast. These were shown to be active in plants by fusing HsvG and HsvB to YFP. localization to the nucleus was dependent on these NLS domains. These achievements indicate that our research plan is feasible and suggest that type III effectors suppress innate immunity and modulate plant hormones. This information has the potential to be exploited to improve disease resistance in agricultural crops.
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Sessa, Guido, and Gregory Martin. A functional genomics approach to dissect resistance of tomato to bacterial spot disease. United States Department of Agriculture, January 2004. http://dx.doi.org/10.32747/2004.7695876.bard.
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The research problem. Bacterial spot disease in tomato is of great economic importance worldwide and it is particularly severe in warm and moist areas affecting yield and quality of tomato fruits. Causal agent of spot disease is the Gram-negative bacterium Xanthomonas campestris pv. vesicatoria (Xcv), which can be a contaminant on tomato seeds, or survive in plant debris and in association with certain weeds. Despite the economic significance of spot disease, plant protection against Xcvby cultural practices and chemical control have so far proven unsuccessful. In addition, breeding for resistance to bacterial spot in tomato has been undermined by the genetic complexity of the available sources of resistance and by the multiple races of the pathogen. Genetic resistance to specific Xcvraces have been identified in tomato lines that develop a hypersensitive response and additional defense responses upon bacterial challenge. Central goals of this research were: 1. To identify plant genes involved in signaling and defense responses that result in the onset of resistance. 2. To characterize molecular properties and mode of action of bacterial proteins, which function as avirulence or virulence factors during the interaction between Xcvand resistant or susceptible tomato plants, respectively. Our main achievements during this research program are in three major areas: 1. Identification of differentially expressed genes during the resistance response of tomato to Xcvrace T3. A combination of suppression subtractive hybridization and microarray analysis identified a large set of tomato genes that are induced or repressed during the response of resistant plants to avirulent XcvT3 bacteria. These genes were grouped in clusters based on coordinate expression kinetics, and classified into over 20 functional classes. Among them we identified genes that are directly modulated by expression of the type III effector protein AvrXv3 and genes that are induced also during the tomato resistance response to Pseudomonas syringae pv. tomato. 2. Characterization of molecular and biochemical properties of the tomato LeMPK3MAP kinase. A detailed molecular and biochemical analysis was performed for LeMPK3 MAP kinase, which was among the genes induced by XcvT3 in resistant tomato plants. LeMPK3 was induced at the mRNA level by different pathogens, elicitors, and wounding, but not by defense-related plant hormones. Moreover, an induction of LeMPK3 kinase activity was observed in resistant tomato plants upon Xcvinfection. LeMPK3 was biochemically defined as a dual-specificity MAP kinase, and extensively characterized in vitro in terms of kinase activity, sites and mechanism of autophosphorylation, divalent cation preference, Kₘand Vₘₐₓ values for ATP. 3. Characteriztion of molecular properties of the Xcveffector protein AvrRxv. The avirulence gene avrRxvis involved in the genetic interaction that determines tomato resistance to Xcvrace T1. We found that AvrRxv functions inside the plant cell, localizes to the cytoplasm, and is sufficient to confer avirulence to virulent Xcvstrains. In addition, we showed that the AvrRxv cysteine protease catalytic core is essential for host recognition. Finally, insights into cellular processes activated by AvrRxv expression in resistant plants were obtained by microarray analysis of 8,600 tomato genes. Scientific and agricultural significance: The findings of these activities depict a comprehensive and detailed picture of cellular processes taking place during the onset of tomato resistance to Xcv. In this research, a large pool of genes, which may be involved in the control and execution of plant defense responses, was identified and the stage is set for the dissection of signaling pathways specifically triggered by Xcv.
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Crowley, David E., Dror Minz, and Yitzhak Hadar. Shaping Plant Beneficial Rhizosphere Communities. United States Department of Agriculture, July 2013. http://dx.doi.org/10.32747/2013.7594387.bard.
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PGPR bacteria include taxonomically diverse bacterial species that function for improving plant mineral nutrition, stress tolerance, and disease suppression. A number of PGPR are being developed and commercialized as soil and seed inoculants, but to date, their interactions with resident bacterial populations are still poorly understood, and-almost nothing is known about the effects of soil management practices on their population size and activities. To this end, the original objectives of this research project were: 1) To examine microbial community interactions with plant-growth-promoting rhizobacteria (PGPR) and their plant hosts. 2) To explore the factors that affect PGPR population size and activity on plant root surfaces. In our original proposal, we initially prqposed the use oflow-resolution methods mainly involving the use of PCR-DGGE and PLFA profiles of community structure. However, early in the project we recognized that the methods for studying soil microbial communities were undergoing an exponential leap forward to much more high resolution methods using high-throughput sequencing. The application of these methods for studies on rhizosphere ecology thus became a central theme in these research project. Other related research by the US team focused on identifying PGPR bacterial strains and examining their effective population si~es that are required to enhance plant growth and on developing a simulation model that examines the process of root colonization. As summarized in the following report, we characterized the rhizosphere microbiome of four host plant species to determine the impact of the host (host signature effect) on resident versus active communities. Results of our studies showed a distinct plant host specific signature among wheat, maize, tomato and cucumber, based on the following three parameters: (I) each plant promoted the activity of a unique suite of soil bacterial populations; (2) significant variations were observed in the number and the degree of dominance of active populations; and (3)the level of contribution of active (rRNA-based) populations to the resident (DNA-based) community profiles. In the rhizoplane of all four plants a significant reduction of diversity was observed, relative to the bulk soil. Moreover, an increase in DNA-RNA correspondence indicated higher representation of active bacterial populations in the residing rhizoplane community. This research demonstrates that the host plant determines the bacterial community composition in its immediate vicinity, especially with respect to the active populations. Based on the studies from the US team, we suggest that the effective population size PGPR should be maintained at approximately 105 cells per gram of rhizosphere soil in the zone of elongation to obtain plant growth promotion effects, but emphasize that it is critical to also consider differences in the activity based on DNA-RNA correspondence. The results ofthis research provide fundamental new insight into the composition ofthe bacterial communities associated with plant roots, and the factors that affect their abundance and activity on root surfaces. Virtually all PGPR are multifunctional and may be expected to have diverse levels of activity with respect to production of plant growth hormones (regulation of root growth and architecture), suppression of stress ethylene (increased tolerance to drought and salinity), production of siderophores and antibiotics (disease suppression), and solubilization of phosphorus. The application of transcriptome methods pioneered in our research will ultimately lead to better understanding of how management practices such as use of compost and soil inoculants can be used to improve plant yields, stress tolerance, and disease resistance. As we look to the future, the use of metagenomic techniques combined with quantitative methods including microarrays, and quantitative peR methods that target specific genes should allow us to better classify, monitor, and manage the plant rhizosphere to improve crop yields in agricultural ecosystems. In addition, expression of several genes in rhizospheres of both cucumber and whet roots were identified, including mostly housekeeping genes. Denitrification, chemotaxis and motility genes were preferentially expressed in wheat while in cucumber roots bacterial genes involved in catalase, a large set of polysaccharide degradation and assimilatory sulfate reduction genes were preferentially expressed.
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Manulis, Shulamit, Christine D. Smart, Isaac Barash, Guido Sessa, and Harvey C. Hoch. Molecular Interactions of Clavibacter michiganensis subsp. michiganensis with Tomato. United States Department of Agriculture, January 2011. http://dx.doi.org/10.32747/2011.7697113.bard.
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Clavibacter michiganensis subsp. michiganensis (Cmm), the causal agent of bacterial wilt and canker of tomato, is the most destructive bacterial disease of tomato causing substantial economic losses in Israel, the U.S.A. and worldwide. The molecular strategies that allow Cmm, a Gram-positive bacterium, to develop a successful infection in tomato plants are largely unknown. The goal of the project was to elucidate the molecular interactions between Cmmand tomato. The first objective was to analyze gene expression profiles of susceptible tomato plants infected with pathogenic and endophytic Cmmstrains. Microarray analysis identified 122 genes that were differentially expressed during early stages of infection. Cmm activated typical basal defense responses in the host including induction of defense-related genes, production of scavenging of free oxygen radicals, enhanced protein turnover and hormone synthesis. Proteomic investigation of the Cmm-tomato interaction was performed with Multi-Dimensional Protein Identification Technology (MudPIT) and mass spectroscopy. A wide range of enzymes secreted by Cmm382, including cell-wall degrading enzymes and a large group of serine proteases from different families were identified in the xylem sap of infected tomato. Based on proteomic results, the expression pattern of selected bacterial virulence genes and plant defense genes were examined by qRT-PCR. Expression of the plasmid-borne cellulase (celA), serine protease (pat-1) and serine proteases residing on the chp/tomA pathogenicity island (chpCandppaA), were significantly induced within 96 hr after inoculation. Transcription of chromosomal genes involved in cell wall degradation (i.e., pelA1, celB, xysA and xysB) was also induced in early infection stages. The second objective was to identify by VIGS technology host genes affecting Cmm multiplication and appearance of disease symptoms in plant. VIGS screening showed that out of 160 tomato genes, which could be involved in defense-related signaling, suppression of 14 genes led to increase host susceptibility. Noteworthy are the genes Snakin-2 (inhibitor of Cmm growth) and extensin-like protein (ELP) involved in cell wall fortification. To further test the significance of Snakin -2 and ELP in resistance towards Cmm, transgenic tomato plants over-expressing the two genes were generated. These plants showed partial resistance to Cmm resulting in a significant delay of the wilt symptoms and reduction in size of canker lesion compared to control. Furthermore, colonization of the transgenic plants was significantly lower. The third objective was to assess the involvement of ethylene (ET), jasmonate (JA) and salicylic acid (SA) in Cmm infection. Microarray and proteomic studies showed the induction of enzymes involved in ET and JA biosynthesis. Cmm promoted ET production 8 days after inoculation and SIACO, a key enzyme of ET biosynthesis, was upregulated. Inoculation of the tomato mutants Never ripe (Nr) impaired in ET perception and transgenic plants with reduced ET synthesis significantly delayed wilt symptoms as compared to the wild-type plants. The retarded wilting in Nr plants was shown to be a specific effect of ET insensitivity and was not due to altered expression of defense related genes, reduced bacterial population or decrease in ethylene biosynthesis . In contrast, infection of various tomato mutants impaired in JA biosynthesis (e.g., def1, acx1) and JA insensitive mutant (jai1) yielded unequivocal results. The fourth objective was to determine the role of cell wall degrading enzymes produced by Cmm in xylem colonization and symptoms development. A significance increase (2 to 7 fold) in expression of cellulases (CelA, CelB), pectate lyases (PelA1, PelA2), polygalacturonase and xylanases (XylA, XylB) was detected by qRT-PCR and by proteomic analysis of the xylem sap. However, with the exception of CelA, whose inactivation led to reduced wilt symptoms, inactivation of any of the other cell wall degrading enzymes did not lead to reduced virulence. Results achieved emphasized the complexity involved in Cmm-tomato interactions. Nevertheless they provide the basis for additional research which will unravel the mechanism of Cmm pathogenicity and formulating disease control measures.
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Fluhr, Robert, and Maor Bar-Peled. Novel Lectin Controls Wound-responses in Arabidopsis. United States Department of Agriculture, January 2012. http://dx.doi.org/10.32747/2012.7697123.bard.
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Innate immune responses in animals and plants involve receptors that recognize microbe-associated molecules. In plants, one set of this defense system is characterized by large families of TIR–nucleotide binding site–leucine-rich repeat (TIR-NBS-LRR) resistance genes. The direct interaction between plant proteins harboring the TIR domain with proteins that transmit and facilitate a signaling pathway has yet to be shown. The Arabidopsis genome encodes TIR-domain containing genes that lack NBS and LRR whose functions are unknown. Here we investigated the functional role of such protein, TLW1 (TIR LECTIN WOUNDRESPONSIVE1). The TLW1 gene encodes a protein with two domains: a TIR domain linked to a lectin-containing domain. Our specific aim in this proposal was to examine the ramifications of the TL1-glycan interaction by; A) The functional characterization of TL1 activity in the context of plant wound response and B) Examine the hypothesis that wounding induced specific polysaccharides and examine them as candidates for TL-1 interactive glycan compounds. The Weizmann group showed TLW1 transcripts are rapidly induced by wounding in a JA-independent pathway and T-DNA-tagged tlw1 mutants that lack TLW1 transcripts, fail to initiate the full systemic wound response. Transcriptome methodology analysis was set up and transcriptome analyses indicates a two-fold reduced level of JA-responsive but not JA-independent transcripts. The TIR domain of TLW1 was found to interact directly with the KAT2/PED1 gene product responsible for the final b-oxidation steps in peroxisomal-basedJA biosynthesis. To identify potential binding target(s) of TL1 in plant wound response, the CCRC group first expressed recombinant TL1 in bacterial cells and optimized conditions for the protein expression. TL1 was most highly expressed in ArcticExpress cell line. Different types of extraction buffers and extraction methods were used to prepare plant extracts for TL1 binding assay. Optimized condition for glycan labeling was determined, and 2-aminobenzamide was used to label plant extracts. Sensitivity of MALDI and LC-MS using standard glycans. THAP (2,4,6- Trihydroxyacetophenone) showed minimal background peaks at positive mode of MALDI, however, it was insensitive with a minimum detection level of 100 ng. Using LC-MS, sensitivity was highly increased enough to detect 30 pmol concentration. However, patterns of total glycans displayed no significant difference between different extraction conditions when samples were separated with Dionex ICS-2000 ion chromatography system. Transgenic plants over-expressing lectin domains were generated to obtain active lectin domain in plant cells. Insertion of the overexpression construct into the plant genome was confirmed by antibiotic selection and genomic DNA PCR. However, RT-PCR analysis was not able to detect increased level of the transcripts. Binding ability of azelaic acid to recombinant TL1. Azelaic acid was detected in GST-TL1 elution fraction, however, DHB matrix has the same mass in background signals, which needs to be further tested on other matrices. The major findings showed the importance of TLW1 in regulating wound response. The findings demonstrate completely novel and unexpected TIR domain interactions and reveal a control nexus and mechanism that contributes to the propagation of wound responses in Arabidopsis. The implications are to our understanding of the function of TIR domains and to the notion that early molecular events occur systemically within minutes of a plant sustaining a wound. A WEB site (http://genome.weizmann.ac.il/hormonometer/) was set up that enables scientists to interact with a collated plant hormone database.
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Funkenstein, Bruria, and Shaojun (Jim) Du. Interactions Between the GH-IGF axis and Myostatin in Regulating Muscle Growth in Sparus aurata. United States Department of Agriculture, March 2009. http://dx.doi.org/10.32747/2009.7696530.bard.
Full textAbstract:
Growth rate of cultured fish from hatching to commercial size is a major factor in the success of aquaculture. The normal stimulus for muscle growth in growing fish is not well understood and understanding the regulation of muscle growth in fish is of particular importance for aquaculture. Fish meat constitutes mostly of skeletal muscles and provides high value proteins in most people's diet. Unlike mammals, fish continue to grow throughout their lives, although the size fish attain, as adults, is species specific. Evidence indicates that muscle growth is regulated positively and negatively by a variety of growth and transcription factors that control both muscle cell proliferation and differentiation. In particular, growth hormone (GH), fibroblast growth factors (FGFs), insulin-like growth factors (IGFs) and transforming growth factor-13 (TGF-13) play critical roles in myogenesis during animal growth. An important advance in our understanding of muscle growth was provided by the recent discovery of the crucial functions of myostatin (MSTN) in controlling muscle growth. MSTN is a member of the TGF-13 superfamily and functions as a negative regulator of skeletal muscle growth in mammals. Studies in mammals also provided evidence for possible interactions between GH, IGFs, MSTN and the musclespecific transcription factor My oD with regards to muscle development and growth. The goal of our project was to try to clarify the role of MSTNs in Sparus aurata muscle growth and in particular determine the possible interaction between the GH-IGFaxis and MSTN in regulating muscle growth in fish. The steps to achieve this goal included: i) Determining possible relationship between changes in the expression of growth-related genes, MSTN and MyoD in muscle from slow and fast growing sea bream progeny of full-sib families and that of growth rate; ii) Testing the possible effect of over-expressing GH, IGF-I and IGF-Il on the expression of MSTN and MyoD in skeletal muscle both in vivo and in vitro; iii) Studying the regulation of the two S. aurata MSTN promoters and investigating the possible role of MyoD in this regulation. The major findings of our research can be summarized as follows: 1) Two MSTN promoters (saMSTN-1 and saMSTN-2) were isolated and characterized from S. aurata and were found to direct reporter gene activity in A204 cells. Studies were initiated to decipher the regulation of fish MSTN expression in vitro using the cloned promoters; 2) The gene coding for saMSTN-2 was cloned. Both the promoter and the first intron were found to be polymorphic. The first intron zygosity appears to be associated with growth rate; 3) Full length cDNA coding for S. aurata growth differentiation factor-l I (GDF-II), a closely related growth factor to MSTN, was cloned from S. aurata brain, and the mature peptide (C-terminal) was found to be highly conserved throughout evolution. GDF-II transcript was detected by RT -PCR analysis throughout development in S. aurata embryos and larvae, suggesting that this mRNA is the product of the embryonic genome. Transcripts for GDF-Il were detected by RT-PCR in brain, eye and spleen with highest level found in brain; 4) A novel member of the TGF-Bsuperfamily was partially cloned from S. aurata. It is highly homologous to an unidentified protein (TGF-B-like) from Tetraodon nigroviridisand is expressed in various tissues, including muscle; 5) Recombinant S. aurata GH was produced in bacteria, refolded and purified and was used in in vitro and in vivo experiments. Generally, the results of gene expression in response to GH administration in vivo depended on the nutritional state (starvation or feeding) and the time at which the fish were sacrificed after GH administration. In vitro, recombinantsaGH activated signal transduction in two fish cell lines: RTHI49 and SAFI; 6) A fibroblastic-like cell line from S. aurata (SAF-I) was characterized for its gene expression and was found to be a suitable experimental system for studies on GH-IGF and MSTN interactions; 7) The gene of the muscle-specific transcription factor Myogenin was cloned from S. aurata, its expression and promoter activity were characterized; 8) Three genes important to myofibrillogenesis were cloned from zebrafish: SmyDl, Hsp90al and skNAC. Our data suggests the existence of an interaction between the GH-IGFaxis and MSTN. This project yielded a great number of experimental tools, both DNA constructs and in vitro systems that will enable further studies on the regulation of MSTN expression and on the interactions between members of the GHIGFaxis and MSTN in regulating muscle growth in S. aurata.