Bibliografie tematiche / Bacteria research

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Letteratura scientifica selezionata sul tema "Bacteria research"

Autore: Grafiati
Pubblicato: 4 giugno 2021
Ultima modifica: 20 febbraio 2023

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Articoli di riviste sul tema "Bacteria research"

1

Tsai, Wen Po, Hui Wen Liao, Ho Ji Chen e Kuo Chang Jane. "A Research of Reservoir Sediment Solidification Using Biotechnology". Advanced Materials Research 610-613 (dicembre 2012): 2761–65. http://dx.doi.org/10.4028/www.scientific.net/amr.610-613.2761.

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At the end of 2010, almost all reservoirs in Taiwan have sedimentation problem. Sedimentation in major reservoirs, such as Wushoh reservoir, had reached 63.73% of its storage capacity in 2009, and must undergo dredging. However, agencies responsible for the final processing stages of reservoir sediments failed to come up with a breakthrough. Limitations established by environmental protection laws also hindered proper dredging of the reservoirs. Hence, further investigation was required for solidifying and reusing reservoir sediments. This research focused on the reuse of Wushoh reservoir sediments. Experimental results showed that when bacteria Bacillus Pastuerii(B.P.) was utilized in sediment solidification, higher bacterial concentrations could induce higher sedimentation of calcium carbonate. In a 70% Urea-CaCl2 medium, a bacterial concentration of 100% resulted in the highest compressive strength that was 30% higher than the control group (bacterial concentration of 0%). Therefore, bacteria can be used to solidify sediments and improve compressive strength. In specimens treated with higher concentrations of bacteria, more square and polygonal crystals were observed via SEM. X-ray powder diffractometer (XRD) analysis showed that bacteria-treated sediments contained calcium carbonate crystals in every stage of processing. Hence, it was shown that bacteria can promote solidification by inducing calcium carbonate sedimentation.
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Sanchez, Jorge E., Erica L. Jacovetty, Bridget Carragher, Clinton S. Potter e Rebecca E. Taurog. "Introducing Students to Research: Electron Microscopy of Bacteriophages". Microscopy Today 18, n. 4 (luglio 2010): 30–33. http://dx.doi.org/10.1017/s1551929510000416.

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Abstract (sommario):
Bacteriophages, as the name “bacteria-eater” suggests, are viruses that infect bacteria. Bacteriophages, often abbreviated as “phages,” have receptors that bind to specific bacterial species, thus there are many types of bacteriophages. Once a phage interacts with its target bacterium, the phage injects its genetic material into the bacterial host where the phage is replicated to produce many new phages that then leave the host via cell lysis.
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3

Scolnik, P. A., e B. L. Marrs. "Genetic Research with Photosynthetic Bacteria". Annual Review of Microbiology 41, n. 1 (ottobre 1987): 703–26. http://dx.doi.org/10.1146/annurev.mi.41.100187.003415.

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4

Sheldon, Tony. "Europe to standardize bacteria research". Nature Medicine 7, n. 6 (giugno 2001): 645. http://dx.doi.org/10.1038/88987.

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Felton, Michael. "Research Profiles: Accurately identifying bacteria". Analytical Chemistry 75, n. 7 (aprile 2003): 143 A. http://dx.doi.org/10.1021/ac0312817.

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6

Zhou, De Ming, He Li, Rong Li, Dan Xue Zhu e Yi Ming Tan. "Research on the Preparation of Fir Bacterial Fertilizer Using Biological Material". Advanced Materials Research 590 (novembre 2012): 100–105. http://dx.doi.org/10.4028/www.scientific.net/amr.590.100.

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The azotobacter bacteria and the phosphate-solubilizing bacteria are separated and filtered from the rhizosphere soil of the fir plantation and the enzyme activity of azotobacter bacteria, the solubilizing power of phosphate-solubilizing bacteria and the characteristics of PGPR bacteria to produce IAA are measured in this paper. The results show that: there are 5 of the 16 azotobacter bacteria whose enzyme activity is greater than 150 nmol•mL-1•h-1, respectively NGJ-4, NGX-5, NGX-4, NGX-8 and NGJ-8. Py16, Py10 and Py3 own the strongest capacity to dissolve organic phosphorus, respectively 71.31 mg / L, 59.07 mg of / L and 65.14 mg / L; Pw10，Pw6 and Pw20 own the strongest capacity to dissolve inorganic phosphorus, respectively 232.0 mg/L，185.9 mg/L，172.6 mg/L. Py18，Py16 and Py3 own the strongest capacity to produce IAA and dissolve the organic phosphorus bacteria, respectively 38.80mg / L, and 37.29mg / L, and 35.79mg / L; Pw6, Pw8 and Pw21 own the strongest capacity to produce IAA and dissolve the inorganic phosphorus bacteria, respectively 45.340 mg/L, 39.340 mg/L, 27.480 mg/ L. Based on these results, the strains of NGJ-4, NGX-5 and NGJ-8 are selected to prepare the microbial compound bacterial fertilizer using Py16, Py3 and Pw6. Then the azotobacter bacteria, organic phosphate-solubilizing bacteria and inorganic phosphate-solubilizing bacteria is respectively diluted to the solution with the ratio of 15%, and then mix them with the volume proportion of 1.5:1:1 to obtain the mixed bacteria liquid; the proportion of solid carrier ash is 20%, the proportion of fermentation medium is 50%, and the proportion of the mixed bacteria liquid is 30%.
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Sun, Yue, Lingxian Meng, Yuxin Zhang, Dan Zhao e Yunfeng Lin. "The Application of Nucleic Acids and Nucleic Acid Materials in Antimicrobial Research". Current Stem Cell Research & Therapy 16, n. 1 (1 dicembre 2021): 66–73. http://dx.doi.org/10.2174/1574888x15666200521084417.

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Abstract (sommario):
Due to the misuse of antibiotics, multiple drug-resistant pathogenic bacteria have increasingly emerged. This has increased the difficulty of treatment as these bacteria directly affect public health by diminishing the potency of existing antibiotics. Developing alternative therapeutic strategies is the urgent need to reduce the mortality and morbidity related to drug-resistant bacterial infections. In the past 10 to 20 years, nanomedicines have been widely studied and applied as an antibacterial agent. They have become a novel tool for fighting resistant bacteria. The most common innovative substances, metal and metal oxide nanoparticles (NPs), have been widely reported. Until recently, DNA nanostructures were used alone or functionalized with specific DNA sequences by many scholars for antimicrobial purposes which were alternatively selected as therapy for severe bacterial infections. These are a potential candidate for treatments and have a considerable role in killing antibiotic-resistant bacteria. This review involves the dimensions of multidrug resistance and the mechanism of bacteria developing drug resistance. The importance of this article is that we summarized the current study of nano-materials based on nucleic acids in antimicrobial use. Meanwhile, the current progress and the present obstacles for their antibacterial and therapeutic use and special function of stem cells in this field are also discussed.
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Pühler, Alfred, Matthieu Arlat, Anke Becker, Michael Göttfert, John P. Morrissey e Fergal O’Gara. "What can bacterial genome research teach us about bacteria–plant interactions?" Current Opinion in Plant Biology 7, n. 2 (aprile 2004): 137–47. http://dx.doi.org/10.1016/j.pbi.2004.01.009.

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Seely, Kevin D., Amanda D. Morgan, Lauren D. Hagenstein, Garrett M. Florey e James M. Small. "Bacterial Involvement in Progression and Metastasis of Colorectal Neoplasia". Cancers 14, n. 4 (17 febbraio 2022): 1019. http://dx.doi.org/10.3390/cancers14041019.

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Abstract (sommario):
While the gut microbiome is composed of numerous bacteria, specific bacteria within the gut may play a significant role in carcinogenesis, progression, and metastasis of colorectal carcinoma (CRC). Certain microbial species are known to be associated with specific cancers; however, the interrelationship between bacteria and metastasis is still enigmatic. Mounting evidence suggests that bacteria participate in cancer organotropism during solid tumor metastasis. A critical review of the literature was conducted to better characterize what is known about bacteria populating a distant site and whether a tumor depends upon the same microenvironment during or after metastasis. The processes of carcinogenesis, tumor growth and metastatic spread in the setting of bacterial infection were examined in detail. The literature was scrutinized to discover the role of the lymphatic and venous systems in tumor metastasis and how microbes affect these processes. Some bacteria have a potent ability to enhance epithelial–mesenchymal transition, a critical step in the metastatic cascade. Bacteria also can modify the microenvironment and the local immune profile at a metastatic site. Early targeted antibiotic therapy should be further investigated as a measure to prevent metastatic spread in the setting of bacterial infection.
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Decker, Amanda R., Tetsuhiro Harimoto, Steve A. Sastra, Tal Danino e Kenneth Olive. "Abstract B028: Bacterial cytotoxin therapy limits tumor growth for pancreatic ductal adenocarcinoma". Cancer Research 82, n. 22_Supplement (15 novembre 2022): B028. http://dx.doi.org/10.1158/1538-7445.panca22-b028.

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Abstract (sommario):
Abstract Treating pancreatic ductal adenocarcinoma (PDAC) with systemic chemotherapeutic drugs has remained a challenge, due in part to the hypovascularized and poorly perfused nature of PDAC tumors, impeding the accumulation of systemically delivered drugs. Several clinical trials aimed at improving drug delivery in PDAC, through targeting of ECM components (HALO-301) or stromal angiogenic signaling (IPI-926-03) have unfortunately not been effective. However, the features that have interfered with systemic therapy in PDAC are potential advantages for the use of bacterial therapies, as bacteria can actively migrate through tissues, thrive in hypoxic microenvironments, and benefit from local immune suppression. Recent developments in the field of synthetic biology have made it possible to engineer complex logic circuits into bacteria, enabling the production of anticancer therapies directly within the tumor parenchyma. Furthermore, live bacteria, once colonized within the tumor niche, are capable of providing a stable source of anticancer compounds directly, rather than relying on repeated systemic doses. We have therefore worked to develop novel bacterial strains and demonstrate preclinical efficacy of a novel strain of therapeutic bacteria for targeting PDAC. We began by testing a range of bacteria-produced toxins and identified the pore-forming protein theta toxin as having the greatest effect in both 2D cell culture and PDAC explant (tissue slice) models. We then engineered a non-toxic probiotic bacteria, E. coli Nissle 1917, to produce either theta toxin or GFP following induction with acyl-homoserine lactone (AHL). To assess preclinical efficacy, we performed intratumoral injections of live GFP- and theta-expressing bacteria into the “KPC” genetically engineered mouse model (Kras LSL.G12D/+; Tp53 LSL.R172H/+; PdxCre tg/+). While GFP-producing bacteria did not induce a change in tumor growth kinetics, treatment with theta toxin-producing bacteria demonstrated prolonged stabilization of tumor growth, increasing the doubling time from 13.7 days (GFP) to 32.5 days (theta) without additional therapy. Indeed, one theta-treated KPC animal lived 113 days following a single bacterial injection, compared to a median of ~12 days for vehicle- or gemcitabine-treated historical controls. Histological analyses demonstrated that diffuse populations of bacteria co-localized with regions of tumor necrosis and cell death, but that bacterial presence and evidence of increased cell death was not observed in healthy tissues, such as the lung, liver, intestine, and diaphragm. Strikingly, while there was minimal spread of bacteria to non-tumor tissues, we observed translocation of the bacteria to regions of liver metastases and distant papillomas following injection of the primary pancreatic tumor, suggesting a mechanism for targeting both known and unknown metastases following local administration. Together these studies demonstrate potent preclinical activity of cytotoxic bacterial therapy as a novel strategy to circumvent the challenges of systemic treatment of PDAC. Citation Format: Amanda R. Decker, Tetsuhiro Harimoto, Steve A. Sastra, Tal Danino, Kenneth Olive. Bacterial cytotoxin therapy limits tumor growth for pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr B028.
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Tesi sul tema "Bacteria research"

1

McGinley, Susan. "Working Together on Nitrogen-Fixing Bacteria". College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 1993. http://hdl.handle.net/10150/622335.

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Han, Yeong-Hwan. "The microaerophilic nature of Wolinella recta, Wolinella curva, Bacteroides ureolyticus, and Bacteroides gracilis". Diss., Virginia Tech, 1991. http://hdl.handle.net/10919/39699.

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Abstract (sommario):
Broad relationships among bacteria can be identified by ribosomal RNA analysis, but the resulting groups may not be easily definable by phenotypic characteristics. This is exemplified by the genus Campylobacter, which consists of at least three separate groups that cannot be differentiated readily by phenotypic characteristics. Examination of the type strains of all Campylobacter species (except Campylobacter pylori), Wolinella recta, Wolinella curva, Bacteroides ureolyticus, and Bacteroides gracilis revealed that sheathed flagella occur only in species of rRNA group II (except W.succinogenes). This is helpful in differentiating this group. Campylobacters are microaerophilic: they can respire with oxygen but cannot grow at the full level of oxygen found in an air atmosphere (21% O₂). Although W. recta, W. curva, B. ureolyticus, and B. gracilis are closely related to the campylobacters of rRNA group I, they were thought to be anaerobes, incapable of oxygen-dependent growth and of respiring with O₂. However, the present study revealed that they are in fact microaerophiles. They exhibited oxygen-dependent growth but failed to grow at 21% O₂ and grew only very slightly under anaerobic conditions unless provided with electron acceptors such as fumarate and nitrate. They exhibited 0₂ uptake with H₂ or formate as electron donors (W. recta showed only a low O₂ uptake with H₂). Oxygen uptake was inhibited by KCN and 2-heptyl-4-hydroxyquinoline N-oxide. The organisms possessed membrane bound cytochromes (cytochromes b560 and C551-553, and a CO-binding cytochrome c), as well as soluble cytochrome C552 and CO-binding cytochrome c. The cytochromes were reduced by H₂ and formate as electron donors. Proton efflux from cells in anaerobic suspensions containing H₂ or formate occurred upon addition of a pulse of oxygen. With formate as the electron donor, H+/O ratios of W. curva, W. recta, B. ureolyticus, and B. gracilis were 0.75, 1.66,2.06, and 2.04, respectively. With H₂ as the electron donor, H⁺/O ratios of W.curva, B. ureoyticus, and B. gracilis were 1.25, 1.97, and 2.36, respectively; technical difficulties prevented measurement of the ratio in W. recta. Proton translocation was inhibited by the protonophore carbonylcyanide m-chlorophenylhydrazone. The results confirm the relationship of these organisms to campylobacters.
Ph. D.
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3

Mosteller, Tracy M. "Sanitizer efficacy towards attached bacteria". Thesis, Virginia Tech, 1991. http://hdl.handle.net/10919/45049.

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Pseudomonas fluorescens, Yersinia enterocolitica, and Listeria monocytogenes readily attach to both rubber and teflon surfaces. Once attached, a glycocalyx covering forms effectively protecting them from any sanitizer that passes over the surface. Therefore, sanitizers efficacy testing done in the laboratory with pure glycocalyx-free cultures could lead to false assumptions as to the sanitizer's true effectiveness under actual use conditions. Our objectives in this study were: (1) evaluate sanitizer efficacy of in use concentrations toward bacteria attached to gasket materials, (2) examine attachment on rubber versus teflon gaskets, (3) examine different methods of enumeration, (4) compare kill of attached bacteria to suspension tests, (5) determine the minimum inhibitory concentrations of Sanitizers. Iodophor, hypochlorite, acid anionic, peroxyacetic acid, fatty acid and QUAT sanitizers failed to provide an adequate log kill of bacteria attached in levels of 10⁴ to 10⁵. Most of the tests showed that the log kill falls well short of a 3 log reduction goal. Plate counts, impedance microbiology, and the direct epifluorescent filter technique were tested as methods of enumeration. Impedance microbiology was the best method of enumeration, since it allows the estimation of both reversibly and irreversibly attached bacteria. Minimum inhibitory concentration tests demonstrated the increased resistance of attached bacteria as compared to cell suspensions.
Master of Science
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4

Sislak, Christine Demko. "Novel Thermophilic Bacteria Isolated from Marine Hydrothermal Vents". PDXScholar, 2013. https://pdxscholar.library.pdx.edu/open_access_etds/1486.

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As part of a large study aimed at searching for patterns of diversity in the genus Persephonella along the north to south geochemical gradient of the ELSC, ten novel strains of Alphaproteobacteria were isolated unexpectedly. Using defined media under microaerophilic conditions to enrich for Persephonella from chimney samples collected at the seven vent fields on the ELSC and the dilution to extinction by serial dilution method to purify cultures, a total of ten strains belonging to the Alphaproteobacteria were isolated. Two of these isolates, designate MN-5 and TC-2 were chosen for further characterization and are proposed as two new species of a novel genus to be namedThermopetrobacter. Both strains are aerobic, capable of chemoautotrophic growth on hydrogen and grow best at 55°C, pH 6 and 3.0% NaCl. Strain MN-5 is capable of heterotrophic growth on pyruvate and malate and TC-2 is only able to grow heterotrophically with pyruvate. The GC content of MN-5 is 69.1 and TC-2 is 67 mol%. GenBank BLAST results from the 16S rRNA gene reveal the most closely related sequence to MN-5 is 90% similar and the most closely related sequence to strain TC-2 is 89% similar. Sampling at a shallow marine vent on the coast of Vulcano Island, Italy in 2007 led to the isolation of a novel species of Hydrogenothermus, a genus within the Hydrogenothermaceae family. This isolate, designated NV1, represents the secondHydrogenothermusisolated from a shallow marine vent. NV1 cells are rod-shaped, approximately 1.5μm long and 0.7μm wide, motile by means of a polar flagellum and grow singularly or in short chains. Cells grow chemoautotrophically using hydrogen or thiosulfate as electron donors and oxygen as the sole electron acceptor. Growth was observed between 45 and 75°C with an optimum of 65°C (doubling time 140 min), pH 4.0-6.5 and requires NaCl (0.5-6.0% w/v). The G+C content of total DNA is 32 mol%.
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Strobel, Philip Scott. "Inhibition of iron-oxidizing bacteria in wastes from coal and hard-rock mines using the anti-bacterial agent". Thesis, Virginia Tech, 1990. http://hdl.handle.net/10919/42234.

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The production of acid mine drainage (AMD) is catalyzed by iron-oxidizing bacteria primarily of the species Thiobacillus ferrooxidans. By inhibiting these bacteria, the production of AMD can be greatly reduced. One compound found to be effective in the inhibition of T. ferrooxidans is nitrapyrine. N-Serve, a product of Dow Chemical, Inc., is the commercially available form of nitrapyrine. This compound has been widely used in agriculture for nitrification inhibition. The purpose of this study was to determine the effectiveness of N-Serve in reducing the production of AMD under simulated field conditions. A column study was completed using a coal mine waste and a hard-rock mine waste. Eight columns containing 7kg of rock were established for each substrate. Three doses of NServe (22% nitrapyrine) were applied once at the beginning of this study: a high dose 2200 mg/kg, a medium dose 220 mg/kg, and a low dose 22 mg/kg. Duplicate columns were included for each N-Serve dose including two untreated columns to serve as a control for each substrate. Beginning the week after treatment, the columns were leached once a week for 29 weeks with deionized, distilled water (equivalent to 2.5 cm precipitation). Only the highest NServe dose produced a column leachate of significantly better quality than that of the controls. The acidity in the high-dose coal mine columns averaged less than 50 percent of the acidity in the control effluent from week 6 through the end of the study. A monolithic controlled release system utilizing acrylonitrile rubber was successfully developed and tested for use with nitrapyrine. This formulation should withstand the rigors of the environment and with minor modification could produce a variety of release rates.
Master of Science
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McGinley, Susan. "Clostridium perfringens: New Ways to Type Strains of a Deadly Bacteria". College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 1999. http://hdl.handle.net/10150/622290.

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Klinke, Stefan. "Production of bioplastic in recombinant bacteria : from basic research to application /". [S.l.] : [s.n.], 1999. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=13448.

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Gaspar-Rolle, Maria Nelma Pinto. "Attachment of bacteria to teflon and buna-n-rubber gasket materials". Diss., Virginia Tech, 1991. http://hdl.handle.net/10919/39818.

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Abstract (sommario):
Surface analysis of buna-N-rubber and teflon was performed. Scanning electron microscopy was used to analyze the topography of both materials and x-ray microanalysis identified the elemental chemical composition of the polymers. Teflon was primarily a smooth surface with random irregular spots, while buna-N-rubber had a very rough topography with "caverns" and crevices spread over the surface. The x-ray microanalysis showed that there are no impurities on the surface of teflon; however, calcium, silicone and sulfur were present on the surface of buna-N-rubber. Water contact angle measurements indicated that buna-N-rubber was a more hydrophobic surface than teflon. Qualitative analysis of the attachment of Pseudomonas fragi A TCC 4973, Listeria monocytogenes Scott A and Bacillus cereus ATCC 11778 to buna-N-rubber and teflon was assessed by scanning electron microscopy. These bacteria readily attached to both surfaces. Pseudomonas fragi attached after 2 hours in the presence of this microoorganism and Bacillus cereus and Listeria monocytogenes attached at 12 and 24 hours, respectively. Quantitative analysis of the attachment of Pseudomonas fragi to both surfaces as affected by various milk fat concentrations and temperature, and the availability of nutrients (different dilutions of skim milk, casein, casein and lactose, and whey and lactose) was conducted. Attachment was assessed by impedance microbiology. Milk fat content did not play a significant role in the process of attachment of this organism to either type of surfaces; however, significantly greater numbers attached to buna-N-rubber than to teflon. Overall bacteria attached in higher numbers to both surfaces when grown at 21°C, compared to bacteria grown at 4°C. For buna-N-rubber, bacteria attached in significantly higher numbers when the concentration of nutrients was minimal, while for teflon, the results were, in most cases, opposite to these.
Ph. D.
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9

Talwalkar, Akshat, University of Western Sydney, of Science Technology and Environment College e of Science Food and Horticulture School. "Studies on the oxygen toxicity of probiotic bacteria with reference to Lactobacillus acidophilus and Bifidobacterium spp". THESIS_CSTE_SFH_Talwalkar_A.xml, 2003. http://handle.uws.edu.au:8081/1959.7/629.

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Oxygen toxicity is considered significant in the poor survival of probiotic bacteria such as Lactobacillus acidophilus and Bifidobacterium spp. in yoghurts. This study investigated methods to protect these bacteria from oxygen exposure. To confirm the accuracy of the reported survival estimates of L. acidophilus or Bifidobacterium spp. in yoghurts, the reliability of several enumeration media was evaluated with different commercial yoghurts. None of the media however, was found reliable thereby casting doubts on the reported cell numbers of probiotic bacteria in yoghurts. After much research,it was found that although oxygen can be detrimental to L. acidophilus and Bifidobacterium spp.in culture broths, it may not be significant for their poor survival in yoghurts. Nevertheless, techniques such as oxidative stress stress adaption, alternative packaging materials and microencapsulation as investigated in this study, can serve as general protective techniques to help yoghurt manufacturers in maintaining the recommended numbers of probiotic bacteria in their products. This would eventually assist in the efficient delivery of probiotic health benefits to yoghurt consumers.
Doctor of Philosphy (PhD)
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10

Mathias, Elizabeth. "Exopolysaccharides of the Pseudomonas aeruginosa Biofilm Matrix". Ohio University Honors Tutorial College / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1400069245.

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Libri sul tema "Bacteria research"

1

National Symposium on Phytobacteriology (1986 University of Madras). Advances in research on plant pathogenic bacteria. New Delhi, India: Today & Tomorrow's Printers & Publishers, 1988.

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2

Bacterial glycomics: Current research, technology, and applications. Norfolk, UK: Caister Academic Press, 2012.

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Khan, Abdul Arif. Bacteria and Cancer. Dordrecht: Springer Netherlands, 2012.

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4

1978-, Wei Li, a cura di. You tian liu suan yan huan yuan jun fen zi sheng tai xue ji qi huo xing sheng tai tiao kong yan jiu: Research on molecular ecology and activities regulation of oilfield sulfate reducing bacteria. Beijing: Ke xue chu ban she, 2009.

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5

P, Ferranti M., Ferrero G. L, L'Hermite P. 1936-, Commission of the European Communities. Directorate-General for Science, Research, and Development. e Commission of the European Communities. Directorate-General for Energy., a cura di. Anaerobic digestion: Results of research and demonstration projects. London: Elsevier Applied Science, 1987.

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6

W, McBride Brian, e Clark Stuart A, a cura di. Making monoclonals: A practical beginners' guide to the production and characterization of monoclonal antibodies against bacteria and viruses. London: Public Health Laboratory Service, 1988.

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7

1952-, Oren Aharon, Ma Yanhe e SpringerLink (Online service), a cura di. Halophiles and Hypersaline Environments: Current Research and Future Trends. Berlin, Heidelberg: Springer-Verlag Berlin Heidelberg, 2011.

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8

Wahyudi, Aris Tri. Sponge-associated bacteria producing bioactive compounds, screening, analysis of antimicrobial compounds, and its genetic study: Competitive grant of overseas research collaboration and international publication : research report. Bogor: Lembaga Penelitian dan Pengabdian Kepada Masyarakat, Bogor Agricultural University, 2010.

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9

Brewer, Heather M. Anaerobic technology: A review of research, development, and demonstration activity in the agrifood and pulp and paper industries. [Ottawa]: Environnement Canada, 1988.

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10

Toman, Rudolf. Coxiella burnetii: Recent Advances and New Perspectives in Research of the Q Fever Bacterium. Dordrecht: Springer Netherlands, 2012.

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Capitoli di libri sul tema "Bacteria research"

1

Evans, H. J., P. J. Bottomley e W. E. Newton. "Associative Bacteria". In Nitrogen fixation research progress, 419–28. Dordrecht: Springer Netherlands, 1985. http://dx.doi.org/10.1007/978-94-009-5175-4_57.

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2

Busta, F. F., e Peggy M. Foegeding. "Sporeforming Bacteria". In Advances in Meat Research, 165–89. London: Macmillan Education UK, 1986. http://dx.doi.org/10.1007/978-1-349-09145-4_5.

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3

Palleroni, N. J. "Pseudomonas Marginalis, an Interesting Organism for Further Research". In Plant Pathogenic Bacteria, 289–90. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-009-3555-6_60.

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4

Renault, Pierre. "Progress in genetic research of lactic acid bacteria". In Lactic Acid Bacteria, 15–35. Berlin, Heidelberg: Springer Berlin Heidelberg, 1996. http://dx.doi.org/10.1007/978-3-642-61462-0_2.

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Cleland, Robyn E., Deborah Rees, David A. Walker e Peter Horton. "Photoinhibition of Photosynthetic Bacteria". In Current Research in Photosynthesis, 1467–70. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-0511-5_340.

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Adrian, Lorenz, e Frank E. Löffler. "Outlook—The Next Frontiers for Research on Organohalide-Respiring Bacteria". In Organohalide-Respiring Bacteria, 621–27. Berlin, Heidelberg: Springer Berlin Heidelberg, 2016. http://dx.doi.org/10.1007/978-3-662-49875-0_26.

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Firrao, G. "Developing New Concepts in Phytoplasma Research: Where the Virological and Bacteriological Approaches Meet". In Plant Pathogenic Bacteria, 100–102. Dordrecht: Springer Netherlands, 2001. http://dx.doi.org/10.1007/978-94-010-0003-1_19.

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Rudolph, K. "Thirty-five Years of Phytobacteriology Research with Special Emphasis on Pathogenicity of Pseudomonas syringae". In Plant Pathogenic Bacteria, 109–17. Dordrecht: Springer Netherlands, 2001. http://dx.doi.org/10.1007/978-94-010-0003-1_22.

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Benko, Riana, e Terry L. Highley. "Biological Control of Wood-Attacking Fungi Using Bacteria". In Biodeterioration Research, 327–32. Boston, MA: Springer US, 1990. http://dx.doi.org/10.1007/978-1-4757-9453-3_26.

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Lima-de-Faria, A. "Chromosomes of bacteria". In One Hundred Years of Chromosome Research and What Remains to be Learned, 109–11. Dordrecht: Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-017-0167-9_26.

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Atti di convegni sul tema "Bacteria research"

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Khair, Nedaa Kamalalden. "Activity of Antibiotic Producing Bacteria Isolated from Rhizosphere Soil Region of Different Medicinal Plants". In Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2020. http://dx.doi.org/10.29117/quarfe.2020.0093.

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The rhizosphere soil of medicinal plants is rich in microorganisms that develop antibiotics as natural mechanism of protection against other microbes that live in their vicinity. The present study aims to explore the production of antibacterial agents from rhizosphere soil bacteria of 11 medicinal plants and determine their activity against Gram-negative (Pseudomonas aeruginosa, Escherichia coli) and Gram-positive (Bacillus cereus, Staphylococcus aureus) bacteria. Soil samples were collected and used to isolate antibiotic producing bacteria (APB). Those isolates (108) were first tested using Cross-streak method against test bacteria. Then, isolates that showed a positive antibacterial effect (12) were tested by antibiotic susceptibility test (AST) of their cell free supernatant (CFS) and their extracellular and intracellular secondary metabolites extraction which gave positive results. Staphylococcus aureus found to be the most sensitive test bacteria with inhibitory zones ranging from 13.5 - 19 mm. Moreover, combinatorial effect of isolates CFS with two organic acids (3% Acetic acid and 0.4 mg/ml Acetylsalicylic acid), two commercial antibiotics (0.016 mg/ml Augmentin and 0.128 mg/ml Doxycycline), and two pure antibiotics (10 mcg/disk Penicillin and 25mcg/disk Carbenicillin) was in vitro evaluated using AST. The combinations of CFS-carbenicillin showed a marked synergistic activity against all test bacteria. The presence of possible antibacterial agents as acetic acid, lactic acid and citric acid in CFS of APB was confirmed by HPLC analysis. Ultimately, in vitro antibacterial study for rhizosphere soil bacteria in this work suggests the possibility of using these bacterial metabolites in clinical infections caused by selected test bacteria, especially when they combine with antibiotics or organic acids.
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Abdel Samad, Rim, Zulfa Al Disi, Mohammad Ashfaq e Nabil Zouari. "The use of Principle Component Analysis and MALDI-TOF MS for the differentiation of mineral forming Virgibacillus and Bacillus species isolated from Sabkhas". In Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2020. http://dx.doi.org/10.29117/quarfe.2020.0069.

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Occurrence of mineral forming and other bacteria in mats is well demonstrated. However, their high diversity shown by ribotyping was not explained, although it could explain the diversity of formed minerals. Common biomarkers as well as phylogenic relationships are useful tools to clustering the isolates and predict their potential role in the natural niche. In this study, combination of MALDI-TOF MS with PCA was shown a powerful tool to categorize 35 mineral forming bacterial strains isolated from Dohat Fshaikh sabkha, at northwest of Qatar (23 from decaying mats and 12 from living ones). 23 strains from decaying mats belong to Virgibacillus genus as identified by ribotyping and are shown highly involved in formation of protodolomite and a diversity of minerals. They were used as internal references in categorization of sabkha bacteria. Combination of isolation of bacteria on selective mineral forming media, their MALDI TOF MS protein profiling and PCA analysis established their relationship in a phyloproteomic based on protein biomarkers including m/z 4905, 3265, 5240, 6430, 7765, and 9815. PCA analysis clustered the studied strains into 3 major clusters, showing strong correspondence to the 3 phyloproteiomic groups that were established by the dendrogram. Both clustering analysis means have evidently demonstrated a relationship between known Virgibacillus strains and other related bacteria based on profiling of their synthesized proteins. Thus, larger populations of bacteria in mats can be easily screened for their potential to exhibit certain activities, which is of ecological, environmental and biotechnological significance.
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Mo, Hongwei. "Research on magnetotactic bacteria optimization algorithm". In 2012 IEEE Fifth International Conference on Advanced Computational Intelligence (ICACI). IEEE, 2012. http://dx.doi.org/10.1109/icaci.2012.6463198.

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Malsam, Jason A., Vishard Ragoonanan, Daniel R. Bond e Alptekin Aksan. "Desiccation Response of Geobacter sulfurreducens". In ASME 2007 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2007. http://dx.doi.org/10.1115/sbc2007-176271.

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Geobacter sulfurreducens is an electricity producing bacteria. It is used in bacterial fuel cells, microbial-based sensors, and catalytic surfaces for bioremediation. Further development of such applications requires stabilization and preservation of the bacteria as thin films on surfaces. This research investigated G.sulfurreducens response to desiccation to explore the feasibility of room temperature preservation. Room temperature preservation involves drying and storing bacteria at ambient conditions. Dried bacteria can be revived on demand by the addition of water.
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Yulianti, Evy, e Anna Rakhmawati. "Screening and characterization of phosphate solubilizing bacteria from isolate of thermophilic bacteria". In THE 4TH INTERNATIONAL CONFERENCE ON RESEARCH, IMPLEMENTATION, AND EDUCATION OF MATHEMATICS AND SCIENCE (4TH ICRIEMS): Research and Education for Developing Scientific Attitude in Sciences And Mathematics. Author(s), 2017. http://dx.doi.org/10.1063/1.4995207.

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Al-Ruwaili, M. A. "Bacterial assessment and antibiotic susceptibility of pathogenic bacteria of Domat Al-Jandal Lake, Saudi Arabia". In MICROBES IN APPLIED RESEARCH - Current Advances and Challenges. WORLD SCIENTIFIC, 2012. http://dx.doi.org/10.1142/9789814405041_0007.

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Liu, Xuejun, Mengmeng Wang, Chang Zhu, Mengxing Gou e Xiaohui Yan. "Research progress of functional lactic acid bacteria". In 2017 6th International Conference on Energy, Environment and Sustainable Development (ICEESD 2017). Paris, France: Atlantis Press, 2017. http://dx.doi.org/10.2991/iceesd-17.2017.116.

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Kim, Yootaek, e Kyongwoo Lee. "Carbon Dioxide Reduction by Ceramic Carriers with Photosynthetic Bacteria". In Bioscience and Medical Research 2015. Science & Engineering Research Support soCiety, 2015. http://dx.doi.org/10.14257/astl.2015.116.51.

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Jantan, Nurin Syakirin, Zunita Zakaria, Saleha Abdul Aziz e Fuad Matori. "Occurrence of Pathogenic Bacteria in Blood Cockles, Anadara granosa". In International Conference on Multidisciplinary Research. SCITEPRESS - Science and Technology Publications, 2018. http://dx.doi.org/10.5220/0008888602680272.

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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 e 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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Rapporti di organizzazioni sul tema "Bacteria research"

1

O'Connor, Nancy J. Completion of Biofouling Research on the Effects of Marine Bacteria on the Attachment of Larval Barnacles. Fort Belvoir, VA: Defense Technical Information Center, maggio 1994. http://dx.doi.org/10.21236/ada283044.

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Stanley-Wall, Nicola, e Joana Carneiro. Life of Bacteria over 200 degrees centigrade: Teachers' Guide. University of Dundee, 2022. http://dx.doi.org/10.20933/100001272.

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The “Life of bacteria over 200 degrees centigrade” video was created by the Public Engagement team at the University of Dundee’s School of Life Sciences, in collaboration with the Nicola-Stanley Wall Lab. This video follows a microbiologist performing an experiment in the laboratory and explains how scientists can study bacteria and biofilms. The video can be used by teachers to show their pupils how some microbial research is done in a professional laboratory environment. This guide helps teachers in this process.
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Haynes, Dr Edward, Chris Conyers, Dr Marc Kennedy, Roy Macarthur, Sam McGreig e Dr John Walshaw. What is the Burden of Antimicrobial Resistance Genes in Selected Ready-to-Eat Foods? Food Standards Agency, novembre 2021. http://dx.doi.org/10.46756/sci.fsa.bsv485.

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This study was designed to get a broad estimate of the presence and the types of antimicrobial resistance genes across 52 simple ready-to-eat foods. It was also carried out to understand the benefits and drawbacks of using metagenomic sequencing, a fairly new technology, to study AMR genes. An antimicrobial is any substance that kills or inhibits the growth of microorganisms. It includes antibiotics which are used to treat bacterial infections in both humans and animals. Given the relevant selective pressures, the bacteria itself can change and find ways to survive the effects of an antimicrobials. This results in the bacteria becoming resistant to the ‘killing’ effects of antimicrobials and is known as ‘antimicrobial resistance’. The more we use antimicrobials and antibiotics and the way that we use them can increase the chance that bacteria will become resistant to antimicrobials. This is important as it can lead to infections that become more difficult to treat with drugs and poses a risk to the public health. T Addressing AMR is a national strategic priority for the UK Government which has led to the development of a new 20-year Vision for AMR and the 5-year National Action Plan (NAP), which runs until 2024. The NAP lays out how the UK will address the AMR challenge and takes a ‘One-Health’ approach which spans people, animals, agriculture, food and the environment. The NAP includes a specific section on the importance of better food safety to limit the contamination of foods and spread of AMR. This section emphasises the need to strengthen the evidence base for AMR and food safety through research, surveillance and promoting good practice across the food chain. The FSA is playing its part by continuing to fill evidence gaps on the role that food plays in AMR through the commissioning of research and surveillance. We are also promoting and improving UK food hygiene (‘4Cs’ messages) across the food chain that will help reduce exposure to AMR bacteria.
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Morrison, Mark, e Joshuah Miron. Molecular-Based Analysis of Cellulose Binding Proteins Involved with Adherence to Cellulose by Ruminococcus albus. United States Department of Agriculture, novembre 2000. http://dx.doi.org/10.32747/2000.7695844.bard.

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At the beginning of this project, it was clear that R. albus adhered tightly to cellulose and its efficient degradation of this polysaccharide was dependent on micromolar concentrations of phenylacetic acid (PAA) and phenylpropionic acid (PPA). The objectives for our research were: i) to identify how many different kinds of cellulose binding proteins are produced by Ruminococcus albus; ii) to isolate and clone the genes encoding some of these proteins from the same bacterium; iii) to determine where these various proteins were located and; iv) quantify the relative importance of these proteins in affecting the rate and extent to which the bacterium becomes attached to cellulose. BARD support has facilitated a number of breakthroughs relevant to our fundamental understanding of the adhesion process. First, R. albus possesses multiple mechanisms for adhesion to cellulose. The P.I.'s laboratory has discovered a novel cellulose-binding protein (CbpC) that belongs to the Pil-protein family, and in particular, the type 4 fimbrial proteins. We have also obtained genetic and biochemical evidence demonstrating that, in addition to CbpC-mediated adhesion, R. albus also produces a cellulosome-like complex for adhesion. These breakthroughs resulted from the isolation (in Israel and the US) of spontaneously arising mutants of R. albus strains SY3 and 8, which were completely or partially defective in adhesion to cellulose, respectively. While the SY3 mutant strain was incapable of growth with cellulose as the sole carbon source, the strain 8 mutants showed varying abilities to degrade and grow with cellulose. Biochemical and gene cloning experiments have been used in Israel and the US, respectively, to identify what are believed to be key components of a cellulosome. This combination of cellulose adhesion mechanisms has not been identified previously in any bacterium. Second, differential display, reverse transcription polymerase chain reaction (DD RT-PCR) has been developed for use with R. albus. A major limitation to cellulose research has been the intractability of cellulolytic bacteria to genetic manipulation by techniques such as transposon mutagenesis and gene displacement. The P.I.'s successfully developed DD RT- PCR, which expanded the scope of our research beyond the original objectives of the project, and a subset of the transcripts conditionally expressed in response to PAA and PPA have been identified and characterized. Third, proteins immunochemically related to the CbpC protein of R. albus 8 are present in other R. albus strains and F. intestinalis, Western immunoblots have been used to examine additional strains of R. albus, as well as other cellulolytic bacteria of ruminant origin, for production of proteins immunochemically related to the CbpC protein. The results of these experiments showed that R. albus strains SY3, 7 and B199 all possess a protein of ~25 kDa which cross-reacts with polyclonal anti-CbpC antiserum. Several strains of Butyrivibrio fibrisolvens, Ruminococcus flavefaciens strains C- 94 and FD-1, and Fibrobacter succinogenes S85 produced no proteins that cross-react with the same antiserum. Surprisingly though, F. intestinalis strain DR7 does possess a protein(s) of relatively large molecular mass (~200 kDa) that was strongly cross-reactive with the anti- CbpC antiserum. Scientifically, our studies have helped expand the scope of our fundamental understanding of adhesion mechanisms in cellulose-degrading bacteria, and validated the use of RNA-based techniques to examine physiological responses in bacteria that are nor amenable to genetic manipulations. Because efficient fiber hydrolysis by many anaerobic bacteria requires both tight adhesion to substrate and a stable cellulosome, we believe our findings are also the first step in providing the resources needed to achieve our long-term goal of increasing fiber digestibility in animals.
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Jelinek, Raz, Paul Dawson, Timothy Hanks, William Pennington e Julie Northcutt. Bacterial sensors for food processing environments. United States Department of Agriculture, gennaio 2013. http://dx.doi.org/10.32747/2013.7598157.bard.

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The overall objective of this project was to develop a new bacterial contaminant sensor based upon polydiacetylene(PDA) which is a unique polymer that changes color and configuration in response to external molecular stimuli. While this polymer has been well studied and has been shown to respond to bacterial stimuli in the laboratory, application to food processing environments has not been demonstrated. One hurdle in the application of biosensors in a food processing environment is interference of food sanitizers with the detection of bacteria. Common food sanitizers were evaluated for their response to PDA and different concentrations paving the way for use of modified PDAs developed by the research team to be used in food plants. Further development of PDA bacterial sensors focused on simplifying its application by immobilizing PDA on cotton and paper for use on swabs, wipes and dip papers. Increasing the sensitivity of PDAs was investigated by attaching fluorophores. Future and continued work will include the decoration of PDAs with apatmers to improve the specificity of the biosensor to food pathogens.
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Weinberg, Zwi G., Richard E. Muck, Nathan Gollop, Gilad Ashbell, Paul J. Weimer e Limin Kung, Jr. effect of lactic acid bacteria silage inoculants on the ruminal ecosystem, fiber digestibility and animal performance. United States Department of Agriculture, settembre 2003. http://dx.doi.org/10.32747/2003.7587222.bard.

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The overall objective of the whole research was to elucidate the mechanisms by which LAB silage inoculants enhance ruminant performance. The results generated will permit the development of better silage inoculants that maximize both silage preservation and animal performance. For this one-year BARD feasibility study, the objectives were to: 1. determine whether lactic acid bacteria (LAB) used in inoculants for silage can survive in rumen fluid (RF) 2.select the inoculants that survived best, and 3. test whether LAB silage inoculants produce bacteriocins-like substances. The most promising strains will be used in the next steps of the research. Silage inoculants containing LAB are used in order to improve forage preservation efficiency. In addition, silage inoculants enhance animal performance in many cases. This includes improvements in feed intake, liveweight gain and milk production in 25-40% of studies reviewed. The cause for the improvement in animal performance is not clear but appears to be other than direct effect of LAB inoculants on silage fermentation. Results from various studies suggest a possible probiotic effect. Our hypothesis is that specific LAB strains interact with rumen microorganisms which results in enhanced rumen functionality and animal performance. The first step of the research is to determine whether LAB of silage inoculants survive in RF. Silage inoculants (12 in the U.S. and 10 in Israel) were added to clarified and strained RF. Inoculation rate was 10 ⁶ (clarified RF), 10⁷ (strained RF) (in the U.S.) and 10⁷, 10⁸ CFU ml⁻¹ in Israel (strained RF). The inoculated RF was incubated for 72 and 96 h at 39°C, with and without 5 g 1⁻¹ glucose. Changes in pH, LAB numbers and fermentation products were monitored throughout the incubation period. The results indicated that LAB silage inoculants can survive in RF. The inoculants with the highest counts after 72 h incubation in rumen fluid were Lactobacillus plantarum MTD1 and a L. plantarum/P. cerevisiae mixture (USA) and Enterococcus faecium strains and Lactobacillus buchneri (Israel). Incubation of rumen fluid with silage LAB inoculants resulted in higher pH values in most cases as compared with that of un-inoculated controls. The magnitude of the effect varied among inoculants and typically was enhanced with the inoculants that survived best. This might suggest the mode of action of LAB silage inoculants in the rumen as higher pH enhances fibrolytic microorganisms in the rumen. Volatile fatty acid (VFA) concentrations in the inoculated RF tended to be lower than in the control RF after incubation. However, L. plalltarull1 MTDI resulted in the highest concentrations of VFA in the RF relative to other inoculants. The implication of this result is not as yet clear. In previous research by others, feeding silages which were inoculated with this strain consistently enhanced animal performance. These finding were recently published in Weinberg et.al.. (2003), J. of Applied Microbiology 94:1066-1071 and in Weinberg et al.. (2003), Applied Biochemistry and Biotechnology (accepted). In addition, some strains in our studies have shown bacteriocins like activity. These included Pediococcus pentosaceus, Enterococcus faecium and Lactobacillus plantarum Mill 1. These results will enable us to continue the research with the LAB strains that survived best in the rumen fluid and have the highest potential to affect the rumen environment.
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Morrison, Mark, Joshuah Miron, Edward A. Bayer e Raphael Lamed. Molecular Analysis of Cellulosome Organization in Ruminococcus Albus and Fibrobacter Intestinalis for Optimization of Fiber Digestibility in Ruminants. United States Department of Agriculture, marzo 2004. http://dx.doi.org/10.32747/2004.7586475.bard.

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Improving plant cell wall (fiber) degradation remains one of the highest priority research goals for all ruminant enterprises dependent on forages, hay, silage, or other fibrous byproducts as energy sources, because it governs the provision of energy-yielding nutrients to the host animal. Although the predominant species of microbes responsible for ruminal fiber degradation are culturable, the enzymology and genetics underpinning the process are poorly defined. In that context, there were two broad objectives for this proposal. The first objective was to identify the key cellulosomal components in Ruminococcus albus and to characterize their structural features as well as regulation of their expression, in response to polysaccharides and (or) P AA/PPA. The second objective was to evaluate the similarities in the structure and architecture of cellulosomal components between R. albus and other ruminal and non-ruminal cellulolytic bacteria. The cooperation among the investigators resulted in the identification of two glycoside hydrolases rate-limiting to cellulose degradation by Ruminococcus albus (Cel48A and CeI9B) and our demonstration that these enzymes possess a novel modular architecture specific to this bacterium (Devillard et al. 2004). We have now shown that the novel X-domains in Cel48A and Cel9B represent a new type of carbohydrate binding module, and the enzymes are not part of a ceiluiosome-like complex (CBM37, Xu et al. 2004). Both Cel48A and Cel9B are conditionally expressed in response to P AA/PPA, explaining why cellulose degradation in this bacterium is affected by the availability of these compounds, but additional studies have shown for the first time that neither PAA nor PPA influence xylan degradation by R. albus (Reveneau et al. 2003). Additionally, the R. albus genome sequencing project, led by the PI. Morrison, has supported our identification of many dockerin containing proteins. However, the identification of gene(s) encoding a scaffoldin has been more elusive, and recombinant proteins encoding candidate cohesin modules are now being used in Israel to verify the existence of dockerin-cohesin interactions and cellulosome production by R. albus. The Israeli partners have also conducted virtually all of the studies specific to the second Objective of the proposal. Comparative blotting studies have been conducted using specific antibodies prepare against purified recombinant cohesins and X-domains, derived from cellulosomal scaffoldins of R. flavefaciens 17, a Clostridium thermocellum mutant-preabsorbed antibody preparation, or against CbpC (fimbrial protein) of R. albus 8. The data also suggest that additional cellulolytic bacteria including Fibrobacter succinogenes S85, F. intestinalis DR7 and Butyrivibrio fibrisolvens Dl may also employ cellulosomal modules similar to those of R. flavefaciens 17. Collectively, our work during the grant period has shown that R. albus and other ruminal bacteria employ several novel mechanisms for their adhesion to plant surfaces, and produce both cellulosomal and non-cellulosomal forms of glycoside hydrolases underpinning plant fiber degradation. These improvements in our mechanistic understanding of bacterial adhesion and enzyme regulation now offers the potential to: i) optimize ruminal and hindgut conditions by dietary additives to maximize fiber degradation (e.g. by the addition of select enzymes or PAA/PPA); ii) identify plant-borne influences on adhesion and fiber-degradation, which might be overcome (or improved) by conventional breeding or transgenic plant technologies and; iii) engineer or select microbes with improved adhesion capabilities, cellulosome assembly and fiber degradation. The potential benefits associated with this research proposal are likely to be realized in the medium term (5-10 years).
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Wildung, Raymond E. Field Research in Bacterial Transport. Office of Scientific and Technical Information (OSTI), giugno 2006. http://dx.doi.org/10.2172/896095.

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Tucker, Dan, Hayley MacGregor, Ayako Ebata e Ngo Thi Hoa. Pig Meat and Food Safety in Myanmar: Evidence to Support Practice. Myanmar Pig Partnership, novembre 2022. http://dx.doi.org/10.19088/ids.2022.061.

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Research findings reveal that disease-causing bacteria, including Salmonella, are widespread on pig farms of all sizes in Yangon Region, Myanmar, as well as in pig meat sold to consumers in the city and rural areas. This evidence provides a snapshot of how intensification in pig production can affect food safety – and points to potential responses.
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Coplin, David L., Shulamit Manulis e Isaac Barash. roles Hrp-dependent effector proteins and hrp gene regulation as determinants of virulence and host-specificity in Erwinia stewartii and E. herbicola pvs. gypsophilae and betae. United States Department of Agriculture, giugno 2005. http://dx.doi.org/10.32747/2005.7587216.bard.

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Gram-negative plant pathogenic bacteria employ specialized type-III secretion systems (TTSS) to deliver an arsenal of pathogenicity proteins directly into host cells. These secretion systems are encoded by hrp genes (for hypersensitive response and pathogenicity) and the effector proteins by so-called dsp or avr genes. The functions of effectors are to enable bacterial multiplication by damaging host cells and/or by blocking host defenses. We characterized essential hrp gene clusters in the Stewart's Wilt of maize pathogen, Pantoea stewartii subsp. stewartii (Pnss; formerly Erwinia stewartii) and the gall-forming bacterium, Pantoea agglomerans (formerly Erwinia herbicola) pvs. gypsophilae (Pag) and betae (Pab). We proposed that the virulence and host specificity of these pathogens is a function of a) the perception of specific host signals resulting in bacterial hrp gene expression and b) the action of specialized signal proteins (i.e. Hrp effectors) delivered into the plant cell. The specific objectives of the proposal were: 1) How is the expression of the hrp and effector genes regulated in response to host cell contact and the apoplastic environment? 2) What additional effector proteins are involved in pathogenicity? 3) Do the presently known Pantoea effector proteins enter host cells? 4) What host proteins interact with these effectors? We characterized the components of the hrp regulatory cascade (HrpXY ->7 HrpS ->7 HrpL ->7 hrp promoters), showed that they are conserved in both Pnss and Fag, and discovered that the regulation of the hrpS promoter (hrpSp) may be a key point in integrating apoplastic signals. We also analyzed the promoters recognized by HrpL and demonstrated the relationship between their composition and efficiency. Moreover, we showed that promoter strength can influence disease expression. In Pnss, we found that the HrpXY two-component signal system may sense the metabolic status of the bacterium and is required for full hrp gene expression in planta. In both species, acyl-homoserine lactone-mediated quorum sensing may also regulate epiphytic fitness and/or pathogenicity. A common Hrp effector protein, DspE/WtsE, is conserved and required for virulence of both species. When introduced into corn cells, Pnss WtsE protein caused water-soaked lesions. In other plants, it either caused cell death or acted as an Avr determinant. Using a yeast- two-hybrid system, WtsE was shown to interact with a number of maize signal transduction proteins that are likely to have roles in either programmed cell death or disease resistance. In Pag and Pab, we have characterized the effector proteins HsvG, HsvB and PthG. HsvG and HsvB are homologous proteins that determine host specificity of Pag and Pab on gypsophila and beet, respectively. Both possess a transcriptional activation domain that functions in yeast. PthG was found to act as an Avr determinant on multiple beet species, but was required for virulence on gypsophila. In addition, we demonstrated that PthG acts within the host cell. Additional effector genes have been characterized on the pathogenicity plasmid, pPATHₚₐg, in Pag. A screen for HrpL- regulated genes in Pnsspointed up 18 candidate effector proteins and four of these were required for full virulence. It is now well established that the virulence of Gram-negative plant pathogenic bacteria is governed by Hrp-dependent effector proteins. However; the mode of action of many effectors is still unresolved. This BARD supported research will significantly contribute to the understanding of how Hrp effectors operate in Pantoea spp. and how they control host specificity and affect symptom production. This may lead to novel approaches for genetically engineering plants resistant to a wide range of bacterial pathogens by inactivating the Hrp effectors with "plantabodies" or modifying their receptors, thereby blocking the induction of the susceptible response. Alternatively, innovative technologies could be used to interfere with the Hrp regulatory cascade by blocking a critical step or mimicking plant or quorum sensing signals.
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