Articoli di riviste sul tema "Extracellular microorganism"
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1
Park, Jeong-Su, e Jong-Moon Jeong. "Characterization of Extracellular Cholesterol Oxidase Produced from Soil Microorganism". Journal of the Korean Society of Food Science and Nutrition 37, n. 11 (28 novembre 2008): 1507–14. http://dx.doi.org/10.3746/jkfn.2008.37.11.1507.
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Castro, Guillermo R., Adrián O. Stettler, Marcela A. Ferrero e Faustino Siñeriz. "Selection of an extracellular esterase-producing microorganism". Journal of Industrial Microbiology 10, n. 3-4 (settembre 1992): 165–68. http://dx.doi.org/10.1007/bf01569761.
3
Beeler, Erik, Nicholas Choy, Jonathan Franks, Francis Mulcahy e Om V. Singh. "Extracellular Synthesis and Characterization of Silver Nanoparticles from Alkaliphilic Pseudomonas sp." Journal of Nanoscience and Nanotechnology 20, n. 3 (1 marzo 2020): 1567–77. http://dx.doi.org/10.1166/jnn.2020.16496.
Abstract (sommario):
Bio-nanotechnology offers eco-friendly processes for the synthesis of stable nanoparticles (NPs). We hypothesized that microorganisms isolated from the root nodules of leguminous plants would biosynthesize silver (Ag) bio-nanoparticles. Clover root nodules enriched with nutrient broth (NB) produced four distinct colonies on NA plates. Microbial colonies were purified by repeated streaking and designated as SS6, SS7, SS8, and SS9 for identification using 16S rRNA sequencing. Four species of Pseudomonas were identified with a similarity score of over 99% using the EZ Taxon search engine, and tested for extracellular biosynthesis of AgNPs. Microorganism Pseudomonas taiwanensis-SS8 with alkaliphilic growth characteristics reduced the AgNO3 solution into AgNPs in the shortest time period. AgNPs were characterized using UV-Vis spectrophotometry and electron and transmission electron microscopy. A number of physical (i.e., temperature and time) and chemical (i.e., pH and growth media) parameters were optimized. An efficient polydispersal biosynthesis of AgNPs at pH 8–9 after 48 hrs in NB growth medium was observed. In addition, the AgNPs showed antimicrobial properties against 16 commonly occurring pathogenic microorganisms.
4
Pallares, Roger M., Nguyen T. K. Thanh e Xiaodi Su. "Tunable plasmonic colorimetric assay with inverse sensitivity for extracellular DNA quantification". Chemical Communications 54, n. 80 (2018): 11260–63. http://dx.doi.org/10.1039/c8cc05465g.
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Bhola, Rahul, Shaily M. Bhola, Brajendra Mishra e David L. Olson. "Microbiologically influenced corrosion and its mitigation: (A review)". Material Science Research India 7, n. 2 (8 febbraio 2010): 407–12. http://dx.doi.org/10.13005/msri/070210.
Abstract (sommario):
The microbiologically influenced corrosion (MIC) is one of the most common forms of corrosion that results from the presence and activity of microorganisms. The presence of microorganism aids in the formation of a bio film and constitutes various bacterial cells, extracellular polymeric substrates (EPS) and corrosion products. In this paper, a review on the importance of MIC and various ways to mitigate has been introduced; a brief description of the physical, chemical, electrochemical and biological mitigation methods for MIC has been included and EPS formation mechanism, chemical composition, properties and its influence on corrosion has been discussed.
6
Tatischeff, Irène. "Assets of the non-pathogenic microorganism Dictyostelium discoideum as a model for the study of eukaryotic extracellular vesicles". F1000Research 2 (4 marzo 2013): 73. http://dx.doi.org/10.12688/f1000research.2-73.v1.
Abstract (sommario):
Dictyostelium discoideum microvesicles have recently been presented as a valuable model for eukaryotic extracellular vesicles. Here, the advantages of D. discoideum for unraveling important biological functions of extracellular vesicles in general are detailed. D. discoideum, a non-pathogenic eukaryotic microorganism, belongs to a billion-year-old Amoeboza lineage, which diverged from the animal-fungal lineage after the plant animal-split. During growth and early starvation-induced development, it presents analogies with lymphocytes and macrophages with regard to motility and phagocytosis capability, respectively. Its 6-chromosome genome codes for about 12,500 genes, some showing analogies with human genes. The presence of extracellular vesicles during cell growth has been evidenced as a detoxification mechanism of various structurally unrelated drugs. Controls led to the discovery of constitutive extracellular vesicle secretion in this microorganism, which was an important point. It means that the secretion of extracellular vesicles occurs, in the absence of any drug, during both cell growth and early development. This constitutive secretion of D. discoideum cells is very likely to play a role in intercellular communication. The detoxifying secreted vesicles, which can transport drugs outside the cells, can also act as "Trojan horses", capable of transferring these drugs not only into naïve D. discoideum cells, but into human cells as well. Therefore, these extracellular vesicles were proposed as a new biological drug delivery tool. Moreover, Dictyostelium, chosen by the NIH (USA) as a new model organism for biomedical research, has already been used for studying some human diseases. These cells, which are much easier to manipulate than human cells, can be easily designed in simple conditioned medium experiments. Owing to the increasing consensus that extracellular vesicles are probably important mediators of intercellular communication, D. discoideum is here suggested to constitute a convenient model for tracking as yet unknown biological functions of eukaryotic extracellular vesicles.
7
Linger, Jeffrey G., William S. Adney e Al Darzins. "Heterologous Expression and Extracellular Secretion of Cellulolytic Enzymes by Zymomonas mobilis". Applied and Environmental Microbiology 76, n. 19 (6 agosto 2010): 6360–69. http://dx.doi.org/10.1128/aem.00230-10.
Abstract (sommario):
ABSTRACT Development of the strategy known as consolidated bioprocessing (CBP) involves the use of a single microorganism to convert pretreated lignocellulosic biomass to ethanol through the simultaneous production of saccharolytic enzymes and fermentation of the liberated monomeric sugars. In this report, the initial steps toward achieving this goal in the fermentation host Zymomonas mobilis were investigated by expressing heterologous cellulases and subsequently examining the potential to secrete these cellulases extracellularly. Numerous strains of Z. mobilis were found to possess endogenous extracellular activities against carboxymethyl cellulose, suggesting that this microorganism may harbor a favorable environment for the production of additional cellulolytic enzymes. The heterologous expression of two cellulolytic enzymes, E1 and GH12 from Acidothermus cellulolyticus, was examined. Both proteins were successfully expressed as soluble, active enzymes in Z. mobilis although to different levels. While the E1 enzyme was less abundantly expressed, the GH12 enzyme comprised as much as 4.6% of the total cell protein. Additionally, fusing predicted secretion signals native to Z. mobilis to the N termini of E1 and GH12 was found to direct the extracellular secretion of significant levels of active E1 and GH12 enzymes. The subcellular localization of the intracellular pools of cellulases revealed that a significant portion of both the E1 and GH12 secretion constructs resided in the periplasmic space. Our results strongly suggest that Z. mobilis is capable of supporting the expression and secretion of high levels of cellulases relevant to biofuel production, thereby serving as a foundation for developing Z. mobilis into a CBP platform organism.
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Filio-Rodríguez, Georgina, Iris Estrada-García, Patricia Arce-Paredes, María M. Moreno-Altamirano, Sergio Islas-Trujillo, M. Dolores Ponce-Regalado e Oscar Rojas-Espinosa. "In vivo induction of neutrophil extracellular traps by Mycobacterium tuberculosis in a guinea pig model". Innate Immunity 23, n. 7 (20 settembre 2017): 625–37. http://dx.doi.org/10.1177/1753425917732406.
Abstract (sommario):
In 2004, a novel mechanism of cellular death, called ‘NETosis’, was described in neutrophils. This mechanism, different from necrosis and apoptosis, is characterized by the release of chromatin webs admixed with microbicidal granular proteins and peptides (NETs). NETs trap and kill a variety of microorganisms. Diverse microorganisms, including Mycobacterium tuberculosis, are NET inducers in vitro. The aim of this study was to examine whether M. tuberculosis can also induce NETs in vivo and if the NETs are bactericidal to the microorganism. Guinea pigs were intradermally inoculated with M. tuberculosis H37Rv, and the production of NETs was investigated at several time points thereafter. NETs were detected as early as 30 min post-inoculation and were clearly evident by 4 h post-inoculation. NETs produced in vivo contained DNA, myeloperoxidase, elastase, histones, ROS and acid-fast bacilli. Viable and heat-killed M. tuberculosis, as well as Mycobacterium bovis BCG were efficient NET inducers, as were unilamellar liposomes prepared with lipids from M. tuberculosis. In vitro, guinea pig neutrophils also produced NETs in response to M. tuberculosis. However, neither the in vivo nor the in vitro-produced NETs were able to kill M. tuberculosis. Nevertheless, in vivo, neutrophils might propitiate recruitment and activation of more efficient microbicidal cells.
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Portiansky, Enrique L., María A. Quiroga, Mariana A. Machuca e Carlos J. Perfumo. "Mycoplasma suis in naturally infected pigs: an ultrastructural and morphometric study". Pesquisa Veterinária Brasileira 24, n. 1 (marzo 2004): 1–5. http://dx.doi.org/10.1590/s0100-736x2004000100002.
Abstract (sommario):
Swine eperythrozoonosis is a haemotrophic disease caused by Eperythrozoon suis, actually called Mycoplasma suis, an extracellular bacterial organism that apparently adheres to pig erythrocyte membrane, inducing its deformation and damage. Since little is known about the ultrastructural and morphometrical aspects of this microorganism, the present work aimed to deal with these issues. The ultrastructural study revealed the presence of structures corresponding to tubules disseminated throughout the soma of M. suis. A variable separation between the microorganism membrane and that of the erythrocyte was also observed. The structural and positional attitude of M. suis could allow speculation about its mechanism of action.
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Ichishima, Eiji, Yukihiro Takada, Keijiro Taira e Michio Takeuchi. "Specificities of extracellular and ribosomal serine proteinases from Bacillus natto, a food microorganism". Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology 869, n. 2 (gennaio 1986): 178–84. http://dx.doi.org/10.1016/0167-4838(86)90292-x.
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Dunn, Michael F., e Arthur L. Karr. "Strain distribution and in planta production of an extracellular polysaccharide depolymerase from Bradyrhizobium japonicum". Canadian Journal of Microbiology 38, n. 8 (1 agosto 1992): 857–61. http://dx.doi.org/10.1139/m92-139.
Abstract (sommario):
Thirty-four strains of Bradyrhizobium japonicum were screened for the in vitro production of an extracellular polysaccharide depolymerase active against the B. japonicum acidic extracellular polysaccharide that contains mannose, glucose, galactose, and 4-O-methylgalactose as neutral sugar components. Over 90% of tested strains producing this type of extracellular polysaccharide also produced the extracellular polysaccharide depolymerase, whereas strains producing a compositionally different extracellular polysaccharide did not. In addition, representatives of species related to B. japonicum by extracellular polysaccharide composition or host range were also phenotypically depolymerase negative. Depolymerase was also present in soybean root nodules formed by B. japonicum strain 2143. In contrast to the cell-associated depolymerase activity found in free-living cells of this strain, most of the depolymerase activity present in nodules is free of the bacteroids. The widespread occurrence of the depolymerase among B. japonicum strains and the spatiotemporal distribution of its activity in planta are consistent with the enzyme playing a role in the removal of surface extracellular polysaccharide from the microorganism during the infection of nodulation process. Key words: Bradyrhizobium japonicum, soybean, extracellular polysaccharides, extracellular polysaccharide depolymerase, bacteroids.
12
Millach, Laia, Antoni Solé e Isabel Esteve. "Role ofGeitlerinemasp. DE2011 andScenedesmussp. DE2009 as Bioindicators and Immobilizers of Chromium in a Contaminated Natural Environment". BioMed Research International 2015 (2015): 1–11. http://dx.doi.org/10.1155/2015/519769.
Abstract (sommario):
The aim of this work was to study the potential of the two phototrophic microorganisms, both isolated from Ebro Delta microbial mats, to be used as bioindicators and immobilizers of chromium. The results obtained indicated that (i) the Minimum Metal Concentration (MMC) significantly affecting Chlorophyllaintensity inGeitlerinemasp. DE2011 andScenedesmussp. DE2009 was 0.25 µM and 0.75 µM, respectively, these values being lower than those established by current legislation, and (ii)Scenedesmussp. DE2009 was able to immobilize chromium externally in extracellular polymeric substances (EPS) and intracellularly in polyphosphate (PP) inclusions. Additionally, this microorganism maintained high viability, including at 500 µM. Based on these results, we postulate thatGeitlerinemasp. DE2011 andScenedesmussp. DE2009 are good chromium-indicators of cytotoxicity and, further, thatScenedesmussp. DE2009 plays an important role in immobilizing this metal in a contaminated natural environment.
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Tramice, Annabella, Adele Cutignano, Annalaura Iodice, Annarita Poli, Ilaria Finore e Giuseppina Tommonaro. "Involvement of a Quorum Sensing Signal Molecule in the Extracellular Amylase Activity of the Thermophilic Anoxybacillus amylolyticus". Microorganisms 9, n. 4 (13 aprile 2021): 819. http://dx.doi.org/10.3390/microorganisms9040819.
Abstract (sommario):
Anoxybacillus amylolyticus is a moderate thermophilic microorganism producing an exopolysaccharide and an extracellular α-amylase able to hydrolyze starch. The synthesis of several biomolecules is often regulated by a quorum sensing (QS) mechanism, a chemical cell-to-cell communication based on the production and diffusion of small molecules named “autoinducers”, most of which belonging to the N-acyl homoserine lactones’ (AHLs) family. There are few reports about this mechanism in extremophiles, in particular thermophiles. Here, we report the identification of a signal molecule, the N-butanoyl-homoserine lactone (C4-HSL), from the milieu of A. amylolyticus. Moreover, investigations performed by supplementing a known QS inhibitor, trans-cinnamaldehyde, or exogenous C4-HSL in the growth medium of A. amylolyticus suggested the involvement of QS signaling in the modulation of extracellular α-amylase activity. The data showed that the presence of the QS inhibitor trans-cinnamaldehyde in the medium decreased amylolytic activity, which, conversely, was increased by the effect of exogenous C4-HSL. Overall, these results represent the first evidence of the production of AHLs in thermophilic microorganisms, which could be responsible for a communication system regulating thermostable α-amylase activity.
14
Susilowati, Dwi Ningsih, Indah Sofiana, Kristina Dwi Atmini e Erny Yuniarti. "SCREENING OF ACIT SULPHATE SOILS FUNGI FROM SOUTH KALIMANTAN AS SOURCE OF EXTRACELULAR ENZYMES". Agric 32, n. 1 (16 ottobre 2020): 65–82. http://dx.doi.org/10.24246/agric.2020.v32.i1.p65-82.
Abstract (sommario):
Kalimantan acid sulphate land has the potential to be developed into productive land, with good land optimization. Utilization of rhizosphere microorganism diversity, especially mold can potentially provide a solution in optimizing agricultural land, namely the ability to produce extracellular enzymes. This study aims to determine the potential of mold originating from acid sulphate fields in producing extracellular enzymes (pectinase, chitinase, glucanase, cellulase, and phosphatase). The study was conducted in June-July 2019 at the Microbiology Laboratory, Indonesian Center for Agricultural Biotechnology and Genetic Resources Research and Development. Screening of extracellular enzyme-producing fungi was carried out on selection media. The results obtained by some isolates have the ability to produce extracellular enzymes. Indications of the ability of mold to produce extracellular enzymes are the presence of clear zones in the selection medium. In pectinase, chitinase and glucanase testing all isolates showed negative results. Potential isolates in producing extracellular enzymes include Penicillium sp. Paddy 4.1 (cellulolytic index 2.43), Clonostachys sp. KRMT 17.9 and Penicillium singorense KLK 13.7 (proteolytic indices 3.97 and 3,00, respectively). The difference in index values indicates the variation in the level of enzyme activity.
15
Speziale, Pietro, Carla Renata Arciola e Giampiero Pietrocola. "Fibronectin and Its Role in Human Infective Diseases". Cells 8, n. 12 (26 novembre 2019): 1516. http://dx.doi.org/10.3390/cells8121516.
Abstract (sommario):
Fibronectin is a multidomain glycoprotein ubiquitously detected in extracellular fluids and matrices of a variety of animal and human tissues where it functions as a key link between matrices and cells. Fibronectin has also emerged as the target for a large number of microorganisms, particularly bacteria. There are clear indications that the binding of microorganism’ receptors to fibronectin promotes attachment to and infection of host cells. Each bacterium may use different receptors which recognize specific fibronectin domains, mostly the N-terminal domain and the central cell-binding domain. In many cases, fibronectin receptors have actions over and above that of simple adhesion: In fact, adhesion is often the prerequisite for invasion and internalization of microorganisms in the cells of colonized tissues. This review updates the current understanding of fibronectin receptors of several microorganisms with emphasis on their biochemical and structural properties and the role they can play in the onset and progression of host infection diseases. Furthermore, we describe the antigenic profile and discuss the possibility of designing adhesion inhibitors based on the structure of the fibronectin-binding site in the receptor or the receptor-binding site in fibronectin.
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Wang, Xiaohai, Zhuanzhuan Shi, Zhikai Wang e Xiaoshuai Wu. "Electromagnetic Field Drives the Bioelectrocatalysis of γ-Fe2O3-Coated Shewanella putrefaciens CN32 to Boost Extracellular Electron Transfer". Materials 17, n. 7 (26 marzo 2024): 1501. http://dx.doi.org/10.3390/ma17071501.
Abstract (sommario):
The microbial hybrid system modified by magnetic nanomaterials can enhance the interfacial electron transfer and energy conversion under the stimulation of a magnetic field. However, the bioelectrocatalytic performance of a hybrid system still needs to be improved, and the mechanism of magnetic field-induced bioelectrocatalytic enhancements is still unclear. In this work, γ-Fe2O3 magnetic nanoparticles were coated on a Shewanella putrefaciens CN32 cell surface and followed by placing in an electromagnetic field. The results showed that the electromagnetic field can greatly boost the extracellular electron transfer, and the oxidation peak current of CN32@γ-Fe2O3 increased to 2.24 times under an electromagnetic field. The enhancement mechanism is mainly due to the fact that the surface modified microorganism provides an elevated contact area for the high microbial catalytic activity of the outer cell membrane’s cytochrome, while the magnetic nanoparticles provide a networked interface between the cytoplasm and the outer membrane for boosting the fast multidimensional electron transport path in the magnetic field. This work sheds fresh scientific light on the rational design of magnetic-field-coupled electroactive microorganisms and the fundamentals of an optimal interfacial structure for a fast electron transfer process toward an efficient bioenergy conversion.
17
Lin, Huihua, Shichang Sun, Zipeng Lin, Manting Chen, Lin Fang, Rui Ma, Junhao Lin e Juan Luo. "Bio-carrier–enhanced aerobic granulation: Effects on the extracellular polymeric substances production and microorganism community". Chemosphere 280 (ottobre 2021): 130756. http://dx.doi.org/10.1016/j.chemosphere.2021.130756.
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Nadar, Sahaya, Tabassum Khan, Simon G. Patching e Abdelwahab Omri. "Development of Antibiofilm Therapeutics Strategies to Overcome Antimicrobial Drug Resistance". Microorganisms 10, n. 2 (27 gennaio 2022): 303. http://dx.doi.org/10.3390/microorganisms10020303.
Abstract (sommario):
A biofilm is a community of stable microorganisms encapsulated in an extracellular matrix produced by themselves. Many types of microorganisms that are found on living hosts or in the environment can form biofilms. These include pathogenic bacteria that can serve as a reservoir for persistent infections, and are culpable for leading to a broad spectrum of chronic illnesses and emergence of antibiotic resistance making them difficult to be treated. The absence of biofilm-targeting antibiotics in the drug discovery pipeline indicates an unmet opportunity for designing new biofilm inhibitors as antimicrobial agents using various strategies and targeting distinct stages of biofilm formation. The strategies available to control biofilm formation include targeting the enzymes and proteins specific to the microorganism and those involved in the adhesion pathways leading to formation of resistant biofilms. This review primarily focuses on the recent strategies and advances responsible for identifying a myriad of antibiofilm agents and their mechanism of biofilm inhibition, including extracellular polymeric substance synthesis inhibitors, adhesion inhibitors, quorum sensing inhibitors, efflux pump inhibitors, and cyclic diguanylate inhibitors. Furthermore, we present the structure–activity relationships (SAR) of these agents, including recently discovered biofilm inhibitors, nature-derived bioactive scaffolds, synthetic small molecules, antimicrobial peptides, bioactive compounds isolated from fungi, non-proteinogenic amino acids and antibiotics. We hope to fuel interest and focus research efforts on the development of agents targeting the uniquely complex, physical and chemical heterogeneous biofilms through a multipronged approach and combinatorial therapeutics for a more effective control and management of biofilms across diseases.
19
PĂCEŞILĂ, i., E. RADU, C. C. BÎRSAN e M. CONSTANTIN. "The assessment of the soil mineralization processes along the traffic corridors from urban and rural areas in Romania". Romanian Biotechnological Letters 27, n. 1/2022 (10 gennaio 2022): 3309–14. http://dx.doi.org/10.25083/rbl/27.1/3309-3314.
Abstract (sommario):
The soils of the green areas located near the traffic corridors accumulate different pollutants, especially heavy metals, which have an important impact on the microbial decomposition processes. The extracellular enzymes can be used as an indicator of the metabolic activity of the microorganism communities. Four extracellular enzymes - α and β glucosidase, alkaline phosphatase and alanine aminopeptidase - were assessed in green areas close to the traffic zones in several urban, peri-urban and rural localities in Romania. The data showed that the highest values of enzymatic activities were registered in rural areas. At the same time, the spatial dynamics of the studied enzymes revealed an important variability between the three types of sampled areas, without a clear pattern of their distribution.
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Reis Zambom, Carolina, Fauller Henrique da Fonseca e Saulo Santesso Garrido. "Bio- and Nanotechnology as the Key for Clinical Application of Salivary Peptide Histatin: A Necessary Advance". Microorganisms 8, n. 7 (10 luglio 2020): 1024. http://dx.doi.org/10.3390/microorganisms8071024.
Abstract (sommario):
Candida albicans is a common microorganism of human’s microbiota and can be easily found in both respiratory and gastrointestinal tracts as well as in the genitourinary tract. Approximately 30% of people will be infected by C. albicans during their lifetime. Due to its easy adaptation, this microorganism started to present high resistance to antifungal agents which is associated with their indiscriminate use. There are several reports of adaptive mechanisms that this species can present. Some of them are intrinsic alteration in drug targets, secretion of extracellular enzymes to promote host protein degradation and efflux receptors that lead to a diminished action of common antifungal and host’s innate immune response. The current review aims to bring promising alternatives for the treatment of candidiasis caused mainly by C. albicans. One of these alternatives is the use of antifungal peptides (AFPs) from the Histatin family, like histatin-5. Besides that, our focus is to show how nanotechnology can allow the application of these peptides for treatment of this microorganism. In addition, our intention is to show the importance of nanoparticles (NPs) for this purpose, which may be essential in the near future.
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Ortiz, Martha L. "Aproximaciones a la comprensión de la degradación de la lignina". Orinoquia 13, n. 2 (1 settembre 2009): 137–44. http://dx.doi.org/10.22579/20112629.208.
Abstract (sommario):
Titulo en ingles: Approaches to understanding lignin degradation.RESUMEN: El objetivo de esta revisión es reunir los hallazgos más recientes que aportan a la comprensión de las rutas metabólicas que intervienen en la degradación del biopolímero más recalcitrante del planeta: la lignina. Esta le proporcionó a las plantas resistencia mecánica en sus tejidos para colonizar la tierra y una barrera fisicoquímica ante la infección microbiana. Debido a su naturaleza recalcitrante, la lignina es el precursor principal para la síntesis de la reserva de materia orgánica del suelo, regulando el ciclo del carbono. Adicionalmente, el sistema enzimático extracelular inespecífico que usan los microorganismos para degradar la lignina, ofrece un sinnúmero de moléculas con potencial biotecnológico. Este trabajo pretende estimular la investigación en la degradación de lignina, especialmente en ambientes poco explorados como la Amazorinoquía para el desarrollo de la bioprospección en nuestro país.Palabras clave: Lignina, enzimas, microorganismos, biotecnología.ABSTRACT: This work was aimed at summarising our current knowledge regarding understanding the metabolic routes intervening in lignin degradation, this being the most recalcitrant biopolymer on earth. Lignin provides plant tissues with mechanic resistance for colonising the earth and represents a physicochemical barrier to microbial infection. Lignin is the main precursor for synthesising the reserve of soil organic matter due to its recalcitrant nature, thereby regulating the carbon cycle. The unspecific extracellular enzymatic system used by microorganisms for lignin degradation offers a large number of molecules having biotechnological poten- tial. This work tries to stimulate research into lignin degradation, especially in little-explored environments such as the Amazon-Orinoquía region for developing bioprospecting in Colombia.Key words: Lignin, enzyme, microorganism, biotechnology.
22
Detusheva, E. V., P. V. Slukin e N. K. Fursova. "Molecular-genetic methods for studying microbial biofilms". Bacteriology 5, n. 2 (2020): 49–55. http://dx.doi.org/10.20953/2500-1027-2020-2-49-55.
Abstract (sommario):
The review article contains information on the clinical significance of microbial biofilms and the main modern molecular genetic methods used to study microbial biofilms: comparative study of genome, transcriptome and proteome of planktonic cells and biofilms; genetic control of biofilm extracellular matrix production; analysis of the contribution of individual genes and gene clusters to the formation of the biofilm phenotype; identification of microorganism species in polymicrobial biofilms. Key words: microbial biofilms, molecular genetic methods, genome, transcriptome, proteome, microbial species identification
23
Ge, Li Yun, Huan Huan Deng, De Xiang Gao e Hong Wu Wang. "The Effect of Ferric Ion and Copper Ion on Extracellular Polymeric Substances". Applied Mechanics and Materials 260-261 (dicembre 2012): 1035–40. http://dx.doi.org/10.4028/www.scientific.net/amm.260-261.1035.
Abstract (sommario):
Extracellular polymeric substances (EPS), which are vital cellular polymeric substances, play an important role in biological wastewater treatment. In this paper, four SBRs (blank, added 20mg/L Fe3+, added 40mg/L Cu2+, added both 20mg/L Fe3+ and 40mg/L Cu2+, respectively) were used to investigate the effect of Fe3+ and Cu2+ on EPS produced by microorganism from activated sludge. Carbohydrate and protein were main components of EPS. The total content of EPS, the content of protein and carbohydrate, and the content of DNA in EPS were detected. The results show metal ion had an effect on the formation of EPS and the total content of the EPS. The effect of ferric ion on protein was more obvious than copper ion. Furthermore, the addition of metal ion had little effect on DNA in EPS.
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Pagliai, F. A., e Carlos A. Jerez. "The Secretome of the Extremophilic Acidithiobacillus Ferrooxidans ATCC 23270". Advanced Materials Research 71-73 (maggio 2009): 183–86. http://dx.doi.org/10.4028/www.scientific.net/amr.71-73.183.
Abstract (sommario):
Acidithiobacillus ferrooxidans is a chemolithoautotrophic acidophile capable of catalyzing the oxidation of ferrous iron and sulfur reducing compounds. During the dissolution of ores A. ferrooxidans adheres to the solid substrate by hydrophobic and hydrophilic interactions and also extracellular polymeric substances may be involved. Nevertheless, many of these agents that participate in the process are unknown. Therefore, the identification and characterization of the extracellular proteome of A. ferrooxidans was addressed during this work. First, by searching the genome of A. ferrooxidans ATCC 23270 the putative genes coding for proteins present in most of the different secretion systems (type I, II, IV, V systems and the Usher pathway) were found. Second, when the secretion signal prediction server SubCel 1.0 was used, 26.7 % of the total open reading frames showed possible signals that would allow these proteins to leave the cytoplasm towards the internal and outer membranes, the periplasm, or the extracellular milieu. By using 2D-NEPHGE and MS sequencing we identified the eleven most abundant proteins present in the extracellular fraction. Proteins related to the transport and binding of solutes and the folding of proteins, among others were identified. Along with the non-classical pathway, the protein secretion systems identified could constitute the secretion machinery for the proteins found in the extracellular sub-proteome of A. ferrooxidans that as a whole constitute its secretome. Further studies of the extracellular proteins from this biomining microorganism will be important to find out their possible role if any, during bacteria-mineral interactions.
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Wu, Guangxue, e Michael Rodgers. "Nutrient removal, microbial community and sludge settlement in anaerobic/aerobic sequencing batch reactors without enhanced biological phosphorus removal". Water Science and Technology 61, n. 10 (1 maggio 2010): 2433–41. http://dx.doi.org/10.2166/wst.2010.079.
Abstract (sommario):
Nutrient removal, microbial community and sludge settlement were examined in two 3-litre laboratory-scale anaerobic/aerobic sequencing batch reactors (SBRs). One SBR was operated at 10°C and the other SBR at 20°C. Different from conventional enhanced biological phosphorus removal, most of the soluble sodium acetate was removed in the aerobic phase and no organic carbon uptake or biological phosphorus release occurred in the anaerobic phase. In this type of anaerobic/aerobic SBR, the phosphorus removal and sludge settlement seemed to be unstable, and the dominant microorganism was Zoogloea sp. Although no excess biological phosphorus removal occurred, extracellular phosphorus precipitation contributed a significant proportion to total phosphorus removed. Sludge volume index decreased with increasing phosphorus contents in the biomass under all conditions. The functions of extracellular polymeric substances in sludge settlement and phosphorus removal depended on the environmental conditions applied.
26
Highsmith, Anita K., Phuong Nhan Le, Rima F. Khabbaz e Van P. Munn. "Characteristics of Pseudomonas aeruginosa Isolated From Whirlpools and Bathers". Infection Control 6, n. 10 (ottobre 1985): 407–12. http://dx.doi.org/10.1017/s0195941700063499.
Abstract (sommario):
AbstractPseudomonas aeruginosa is the most frequently isolated microorganism from whirlpool water and lesions associated with outbreaks of dermatitis and folliculitis related to whirlpool exposure. Strains were selected from 19 outbreaks of P. aeruginosa infections (1977 to 1983) associated with whirlpool use; they were examined to determine if the strains possessed unique virulence factors or characteristics that might aid in their selection in the environment.P. aeruginosa, 011, was the predominant serotype isolated from whirlpool water as well as from bathers with dermatitis or folliculitis, followed by serotypes 09, 04, and 03. Antimicrobial susceptibility patterns were similar for all strains. Strains of P. aeruginosa from bathers and water demonstrated statistically significant differences in extracellular enzyme production compared with control strains. P. aeruginosa, serotypes 09 and 011, were found to be sensitive to low levels of chlorine. These data suggest that, if adequate levels of free available chlorine are maintained, P. aeruginosa should have little opportunity to persist in whirlpools.A bather's risk of P. aeruginosa dermatitis or folliculitis appears to be affected primarily by three factors: 1) immersion in water colonized by P. aeruginosa, 2) skin hydration with altered skin flora, and 3) toxic reactions to extracellular enzyme or exotoxins produced by P. aeruginosa. Although a single virulence factor was not identified from the results of this study, there are some indications that the enzymes produced by these microorganisms play an important role in the pathogenesis of disease associated with whirlpool use.
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Drozdova, Margarita, Anna Pozdnyakova, Maria Osintseva, Nadezhda Burova e Varvara Minina. "The microorganism-plant system for remediation of soil exposed to coal mining". Foods and Raw Materials 9, n. 2 (9 novembre 2021): 406–18. http://dx.doi.org/10.21603/2308-4057-2021-2-406-418.
Abstract (sommario):
Introduction. Coal mining causes a radical transformation of the soil cover. Research is required into modern methods and complementary technologies for monitoring technogenic landscapes and their remediation. Our study aimed to assess soil and rhizosphere microorganisms and their potential uses for the remediation of technogenic soils in Russian coal regions.
Study objects and methods. We reviewed scientific articles published over the past five years, as well as those cited in Scopus and Web of Science.
Results and discussion. Areas lying in the vicinity of coal mines and coal transportation lines are exposed to heavy metal contamination. We studied the application of soil remediation technologies that use sorbents from environmentally friendly natural materials as immobilizers of toxic elements and compounds. Mycorrhizal symbionts are used for soil decontamination, such as arbuscular mycorrhiza with characteristic morphological structures in root cortex cells and some mycotallia in the form of arbuscules or vesicles. Highly important are Gram-negative proteobacteria (Agrobacterium, Azospirillum, Azotobacter, Burkholderia, Bradyrizobium, Enterobacter, Pseudomonas, Klebsiella, Rizobium), Gram-positive bacteria (Bacillus, Brevibacillus, Paenibacillus), and Grampositive actinomycetes (Rhodococcus, Streptomyces, Arhtrobacter). They produce phytohormones, vitamins, and bioactive substances, stimulating plant growth. Also, they reduce the phytopathogenicity of dangerous diseases and harmfulness of insects. Finally, they increase the soil’s tolerance to salinity, drought, and oxidative stress. Mycorrhizal chains enable the transport and exchange of various substances, including mineral forms of nitrogen, phosphorus, and organic forms of C3 and C4 plants. Microorganisms contribute to the removal of toxic elements by absorbing, precipitating or accumulating them both inside the cells and in the extracellular space.
Conclusion. Our review of scientific literature identified the sources of pollution of natural, agrogenic, and technogenic landscapes. We revealed the effects of toxic pollutants on the state and functioning of living systems: plants, animals, and microorganisms. Finally, we gave examples of modern methods used to remediate degraded landscapes and reclaim disturbed lands, including the latest technologies based on the integration of plants and microorganisms.
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Sukhina, M. A., I. A. Kalashnikova, V. N. Kashnikov, A. V. Veselov, V. I. Mikhalevskaya e A. Yu Piyadina. "EFFECT OF ANTIMICROBIAL AGENTS ON THE BIOFILM GROWTH OF CLINICAL ISOLATES". Koloproktologia, n. 2 (30 giugno 2018): 78–84. http://dx.doi.org/10.33878/2073-7556-2018-0-2-78-84.
Abstract (sommario):
OBJECTIVE. To study the effect of active extracellular substances of lactobacilli and antimicrobial agents on the inhibition and destruction of the biofilms formed clinically relevant microorganism strains. MATERIALS AND METHODS. The study of the impact of different agents on the biofilmformation and growth was carried out on resistant clinical strains of microorganisms obtainedfrom patients with post-surgical infectious inflammatory complications. We used wound dressing solution, cutaneous antiseptic, filtrates of 19 clinical strains of lactobacilli and a strain of Lactobacillus plantarum from the probiotic «Lactobacterin dry» (Microgen Nizhny Novgorod, series 46 / 06-1209) as a reference strain-producer of bacteriocins for biofilm inhibition. Biofilms were incubated for 48 hours on glass carriers at 37°C and visualized with a light microscope at 960x magnifying. RESULTS. All substances possess a good inhibitory potential and have approximately same level of effect. The skin antiseptic and wound washing fluid have only an inhibiting effect on the biofilmformation process, while the having a bactericidal effect on plantonicform of the cells. The lactobacilli filtrate inhibited the biofilmformation and was also able to destroy preformed 24-hour bacterial films. CONCLUSION. The use of lactobacilli bacteriocins can reveal additional opportunities for combating the infection associated with biofilm forming microorganisms.
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Mejía-Manzano, Luis Alberto, Patricia Vázquez-Villegas, Luis Vicente Prado-Cervantes, Kristeel Ximena Franco-Gómez, Susana Carbajal-Ocaña, Daniela Lizeth Sotelo-Cortés, Valeria Atehortúa-Benítez, Miguel Delgado-Rodríguez e Jorge Membrillo-Hernández. "Advances in Material Modification with Smart Functional Polymers for Combating Biofilms in Biomedical Applications". Polymers 15, n. 14 (12 luglio 2023): 3021. http://dx.doi.org/10.3390/polym15143021.
Abstract (sommario):
Biofilms as living microorganism communities are found anywhere, and for the healthcare sector, these constitute a threat and allied mechanism for health-associated or nosocomial infections. This review states the basis of biofilms and their formation. It focuses on their relevance for the biomedical sector, generalities, and the major advances in modified or new synthesized materials to prevent or control biofilm formation in biomedicine. Biofilm is conceptualized as an aggregate of cells highly communicated in an extracellular matrix, which the formation obeys to molecular and genetic basis. The biofilm offers protection to microorganisms from unfavorable environmental conditions. The most frequent genera of microorganisms forming biofilms and reported in infections are Staphylococcus spp., Escherichia spp., and Candida spp. in implants, heart valves, catheters, medical devices, and prostheses. During the last decade, biofilms have been most commonly related to health-associated infections and deaths in Europe, the United States, and Mexico. Smart, functional polymers are materials capable of responding to diverse stimuli. These represent a strategy to fight against biofilms through the modification or synthesis of new materials. Polypropylene and poly-N-isopropyl acrylamide were used enough in the literature analysis performed. Even smart polymers serve as delivery systems for other substances, such as antibiotics, for biofilm control.
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Nevin, Kelly P., e Derek R. Lovley. "Mechanisms for Accessing Insoluble Fe(III) Oxide during Dissimilatory Fe(III) Reduction by Geothrix fermentans". Applied and Environmental Microbiology 68, n. 5 (maggio 2002): 2294–99. http://dx.doi.org/10.1128/aem.68.5.2294-2299.2002.
Abstract (sommario):
ABSTRACT Mechanisms for Fe(III) oxide reduction were investigated in Geothrix fermentans, a dissimilatory Fe(III)-reducing microorganism found within the Fe(III) reduction zone of subsurface environments. Culture filtrates of G. fermentans stimulated the reduction of poorly crystalline Fe(III) oxide by washed cell suspensions, suggesting that G. fermentans released one or more extracellular compounds that promoted Fe(III) oxide reduction. In order to determine if G. fermentans released electron-shuttling compounds, poorly crystalline Fe(III) oxide was incorporated into microporous alginate beads, which prevented contact between G. fermentans and the Fe(III) oxide. G. fermentans reduced the Fe(III) within the beads, suggesting that one of the compounds that G. fermentans releases is an electron-shuttling compound that can transfer electrons from the cell to Fe(III) oxide that is not in contact with the organism. Analysis of culture filtrates by thin-layer chromatography suggested that the electron shuttle has characteristics similar to those of a water-soluble quinone. Analysis of filtrates by ion chromatography demonstrated that there was as much as 250 μM dissolved Fe(III) in cultures of G. fermentans growing with Fe(III) oxide as the electron acceptor, suggesting that G. fermentans released one or more compounds capable of chelating and solubilizing Fe(III). Solubilizing Fe(III) is another strategy for alleviating the need for contact between cells and Fe(III) oxide for Fe(III) reduction. This is the first demonstration of a microorganism that, in defined medium without added electron shuttles or chelators, can reduce Fe(III) derived from Fe(III) oxide without directly contacting the Fe(III) oxide. These results are in marked contrast to those with Geobacter metallireducens, which does not produce electron shuttles or Fe(III) chelators. These results demonstrate that phylogenetically distinct Fe(III)-reducing microorganisms may use significantly different strategies for Fe(III) reduction. Thus, it is important to know which Fe(III)-reducing microorganisms predominate in a given environment in order to understand the mechanisms for Fe(III) reduction in the environment of interest.
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Simon, L., B. Bouchet, C. Caye-Vaugien e D. J. Gallant. "Pullulan elaboration and differentiation of the resting forms in Aureobasidium pullulans". Canadian Journal of Microbiology 41, n. 1 (1 gennaio 1995): 35–45. http://dx.doi.org/10.1139/m95-005.
Abstract (sommario):
To identify the cellular forms that are responsible for the synthesis of pullulan produced by Aureobasidium pullulans, we performed cytochemical and ultrastructural localizations of glucan in the cellular forms of this microorganism (blastospores and resting forms). Growth conditions, cell populations, and pullulan production were studied concurrently. Our results are consistent with a model in which the resting forms (swollen cells and chlamydospores) might be primarily involved in this extracellular polysaccharide elaboration. At the cellular level, pullulan production could be the result of three main stages: (i) cell wall thickening and extracellular polysaccharide synthesis by the swollen cell, (ii) fibrillar arrangement of this polysaccharide into pullulan along a capsular network around the chlamydospore, and (iii) subcellular hydrolysis separating the capsule from the periplasmic zone and consequently permitting the solubilization of pullulan in the culture medium. A melanization process in the outer layer of the cell wall and the capsule accompanies these patterns.Key words: Aureobasidium pullulans, capsule, cytochemistry, polysaccharide, pullulan, resting forms.
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Khushk, Imrana. "Environmental Friendly Production of Amylase from Aspergillus niger EFRL-FC-024 Using Corn Waste as Carbon Source". Pakistan Journal of Analytical & Environmental Chemistry 22, n. 1 (23 giugno 2021): 165–71. http://dx.doi.org/10.21743/pjaec/2021.06.17.
Abstract (sommario):
Amylase is an indispensable and industrially important enzyme that hydrolyzes carbohydrates particularly starch into simple sugars. Amylase enzymes have been isolated from various sources such as microbes, animals and plants. However, microorganisms are highly preferred as compared to plants and animal sources. Amylases of fungal origin are highly stable compared to amylases produced by bacterial species. The aim of this study was to investigate the production of extracellular amylase enzyme from Aspergillus niger EFRL-FC-024 using sugarcane bagasse and corn waste as an energy source under submerge fermentation conditions. Primarily, the fungal strain was grown for 6 days using sugarcane bagasse and corn waste, respectively. Mainly, the growth of a microorganism was also evaluated using different pH, temperature and incubation periods. The results revealed maximum amylase production of 1.64 U/mL when A. niger was cultured for 96 h using corn waste. Moreover, addition of different nitrogen sources showed the highest amylase production when peptone was supplemented as a nitrogen source. Finally, the effect of pH indicated maximal concentration of amylase enzyme at pH 6.0. The present study will highly be beneficial to explore the role of fungal strain A. niger in amylase production at Industrial levels.
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Majumdar, Udayan, Thrisha Alexander, Morris Waskar e Manoj V. Dagaonkar. "Effect of biofilm on colloid attachment in saturated porous media". Water Science and Technology 70, n. 2 (7 maggio 2014): 241–48. http://dx.doi.org/10.2166/wst.2014.197.
Abstract (sommario):
Biofilm plays an important role in controlling the transport of colloids in a porous media. Biofilms are formed when micro-organisms come in contact with substrates, and are able to attach and grow with availability of nutrients. The microorganisms get embedded in a matrix of the substrate and extracellular polymeric substances which are responsible for the morphology, physico-chemical properties, structure and coherence of the biofilm. In this study, the effect of biofilm and its aging on colloid removal was studied on a glass bead column. Oocysts, polystyrene microspheres and inorganic colloids were used as colloidal particles. Pseudomonas aeruginosa was used as a model biofilm-forming microorganism. Presence of biofilm significantly enhanced colloid removal in the column. After 3 weeks, almost complete colloid removal was observed. The formation of biofilm was confirmed by various physical characterization techniques. During the extended aging study, biofilm sloughed off under shear stress. The loss of biofilm was higher during the early stage of its growth, and subsequently slowed down probably due to the formation of a more rigid biofilm. This research indicates that biofilm formation, maturation and sloughing-off play a critical role in colloid removal through porous media.
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Sahu, Sudarshan, Avinash Sharma, Soham Mukherjee, Deepak Kumar, Fatih Sen, Rupak Nagraik e Avvaru Praveen Kumar. "Role of Nanofibers in Encapsulation of the Whole Cell". International Journal of Polymer Science 2021 (24 novembre 2021): 1–9. http://dx.doi.org/10.1155/2021/4250122.
Abstract (sommario):
In the field of biomaterial research, the electrospinning device is now used to manufacture nanofibers that can be used to encapsulate whole microorganisms such as bacterial cells, funguses, viruses, and even spores. The nanofiber encapsulated cells will have greater significance in the coming future because of their wide variety of applications in various fields. Nanofibers act as microorganism reservoir systems that enhance their properties such as viability, controlled release of products, biomedical applications, and bioremediation. The effect of electrostatic forces on a droplet of liquid polymer or polymer solution is based on electrospinning. Electrospun nanofibers act as ideal native extracellular matrices for microorganisms and have also had a tremendous advantage in drug delivery systems where modern research is still underway. During electrospinning, nearly all microorganisms may be inserted into a polymer matrix that forms a composite nanofiber. The evolution in electrospinning technique over the past few decades has become promising. New ideas have been generated to enhance the techniques and improve the overall applications and properties of nanofibers. This technique has been transformed by the advent of the electrospinning machine. The electrospun nanofibers can be chemically characterized by a wide variety of procedures such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). Electrospinning has various applications, for example, in wastewater treatment, tissue engineering, food industry, drug delivery, agriculture, and cosmetics. Nanofiber encapsulation of microorganisms increased the shelf life of the microorganisms; the cells remain viable for months. It also helps in the control release of bacterial products. The present review demonstrates the role of nanofiber in the encapsulation of the whole cell.
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El-Shanshoury, Abd El-Raheem R., Sobhy E. ElSilk e Mohamed E. Ebeid. "Extracellular Biosynthesis of Silver Nanoparticles Using Escherichia coli ATCC 8739, Bacillus subtilis ATCC 6633, and Streptococcus thermophilus ESh1 and Their Antimicrobial Activities". ISRN Nanotechnology 2011 (17 agosto 2011): 1–7. http://dx.doi.org/10.5402/2011/385480.
Abstract (sommario):
The development of reliable and eco-friendly organisms of silver nanomaterials is an important aspect of current nanotechnology research and application. Recently, microorganisms have been explored as potential biofactory for synthesis of silver nanoparticles. In this study, through screening of common bacteria, we report extracellular biosynthesis of metallic silver nanoparticles by the reduction of aqueous Ag+ using Escherichia coli ATCC 8739, Bacillus subtilis ATCC 6633, and Streptococcus thermophilus ESh1 as potential candidates for the rapid synthesis of silver nanoparticles. The culture supernatant of silver nanoparticles biosynthesis by reduction of silver ion coming in contact with the cell filtrate was fast and was formed within few minutes. UV-visible spectrum of the aqueous media obtained from the above bacteria containing silver ion showed a peak around 420 nm corresponding to the plasmon absorbance of silver nanoparticles. Transmission electron microscopy (TEM) micrographs showed formation of well-dispersed silver nanoparticles in the range of 5–25 nm. X-ray diffraction (XRD) of silver nanoparticles exhibited 2θ values corresponding to the silver nanocrystal. In vitro studies indicated that the formed silver nanoparticles showed variable antimicrobial activity against Escherichia coli, Bacillus subtilis, Salmonella typhimurium, Klebsiella pneumoniae, Staphylococcus aureus, and Pseudomonas aeruginosa and the fungus like yeast (Candida albicans). The diameter of inhibition zone varied according to the silver nanocrystal concentration and the test microorganism.
36
Majeed, Muhammed, Shaheen Majeed, Kalyanam Nagabhushanam, Lincy Lawrence, Sivakumar Arumugam e Lakshmi Mundkur. "Skin Protective Activity of LactoSporin-the Extracellular Metabolite from Bacillus Coagulans MTCC 5856". Cosmetics 7, n. 4 (27 settembre 2020): 76. http://dx.doi.org/10.3390/cosmetics7040076.
Abstract (sommario):
Background: Probiotics and their products are increasingly used in skincare in recent years. Postbiotics are defined as any substance derived through the metabolic activity of a probiotic microorganism, which exerts a direct or indirect beneficial effect on the host. The extracellular metabolites of probiotic bacteria have antimicrobial activities, protect against acne, and improve skin condition. We studied skin protective activities of the extracellular metabolite (LactoSporin) of a spore-forming probiotic Bacillus coagulans MTCC 5856 in vitro. Methods: LactoSporin was evaluated for antioxidant activity by free radical scavenging activity and reactive oxygen quenching activity in human dermal fibroblast cells. Protection of fibroblasts from UV-induced apoptosis and cell death was studied by flow cytometry and neutral red uptake assays. Enzyme inhibition assays were carried out for collagenase, Elastase, and Hyaluronidase. Gene expression studies were carried out using polymerase chain reaction. Results: LactoSporin showed antioxidant activity and was found to protect skin cells from UV-induced apoptosis and cell death. LactoSporin inhibited collagenase, elastase, and hyaluronidase activity and upregulated the expression of hyaluronan synthase, transforming growth factor and epidermal growth factor, which are associated with extracellular matrix integrity. Conclusions: These results suggest LactoSporin is a skin protective postbiotic with wide application in cosmetic formulations.
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KOZIEŁ, NINA, ELŻBIETA KUKIER e KRZYSZTOF KWIATEK. "Clostridium perfringens – epidemiological importance and diagnostics". Medycyna Weterynaryjna 75, n. 01 (2019): 6161–2019. http://dx.doi.org/10.21521/mw.6161.
Abstract (sommario):
Clostridium perfringens is one of the most widespread anaerobic spore forming bacteria found in the environment. The toxotype A of the species inhabits the gastrointestinal tract of birds and mammals exhibiting pathogenic properties in the immunocompromised host. The virulence determinants of C. perfringens are toxins and extracellular enzymes which cause gas gangrene, enteritis necroticans, food poisoning, and non-food borne gastrointestinal infections in humans. The young animals suffer from enterotoxaemia, dysentery and necrotic enteritis due to the anaerobic spore forming bacilli. This article reviews the epidemiological significance of C. perfringens and its disease diagnostics, taking into account all known to date virulence determinants of the microorganism.
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Ren, Kexin, Qiang Wang, Mengkai Hu, Yan Chen, Rufan Xing, Jiajia You, Meijuan Xu, Xian Zhang e Zhiming Rao. "Research Progress on the Effect of Autolysis to Bacillus subtilis Fermentation Bioprocess". Fermentation 8, n. 12 (28 novembre 2022): 685. http://dx.doi.org/10.3390/fermentation8120685.
Abstract (sommario):
Bacillus subtilis is a gram-positive bacterium, a promising microorganism due to its strong extracellular protein secretion ability, non-toxic, and relatively mature industrial fermentation technology. However, cell autolysis during fermentation restricts the industrial application of B. subtilis. With the fast advancement of molecular biology and genetic engineering technology, various advanced procedures and gene editing tools have been used to successfully construct autolysis-resistant B. subtilis chassis cells to manufacture various biological products. This paper first analyses the causes of autolysis in B. subtilis from a mechanistic perspective and outlines various strategies to address autolysis in B. subtilis. Finally, potential strategies for solving the autolysis problem of B. subtilis are foreseen.
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Baktir, Afaf, Zumrotul Koiriyah e Ali Rohman. "A THERMOPHILIC MICROBE PRODUCING DEXTRANASE FROM HEATED SUGAR CANE". Indonesian Journal of Chemistry 5, n. 3 (15 giugno 2010): 224–27. http://dx.doi.org/10.22146/ijc.21794.
Abstract (sommario):
A thermophilic aerobe microorganism designated NP4, was isolated from the heated sugar cane. It grew on dextran, and produced a thermoactive extracellular dextranase. Screening and isolation was done by assay of dextranase activity semi quantitatively on solid medium containing blue dextran. It provided several colonies with different morphology exhibited decolourized zones around, on culture plates containing blue dextran 2000R. The screening resulted in isolation of one microbe which efficiently assimilate dextran as carbon source. Dextranase production from the choised strain in liquid medium was conducted at room temperature for 8 hours with shaking speed of 125 rpm. The dextranase enzyme showed optimum pH of 8 and optimum temperature of 60 oC. Keywords: thermophilic aerobe, sugar cane, dextranase activity.
40
Zhao, Zhiling, Yongji Zhang, Lu Wang e Wenhang Shi. "Effect of Particle Concentration and Pipe Materials on the Formation of Biofilms in Drinking Water Distribution Systems". Water 14, n. 2 (13 gennaio 2022): 224. http://dx.doi.org/10.3390/w14020224.
Abstract (sommario):
Microorganism rebreeding and biofilm shedding enter the water body in the process of a drinking water distribution system (DWDS), which poses a threat to public health. Particles in water can gather pollutants as well as providing favorable growth conditions for bacteria. To date, there are a few studies which focus on the relationship between particles and biofilm formation. Therefore, the microbial diversity of biofilms in the different pipe materials and the effect on particle concentration on biofilm formation were investigated in this study. Experiments were carried out under a simulative DWDS (including iron (DI) and polyvinyl chloride (PVC) pipe). The results showed that the microbial diversity in biofilms followed this order: DI pipe > PVC pipe > DI pipe (upper). Moreover, the microbial biomass of biofilm and the fluorescence intensity of extracellular polymeric substances (EPS, produced by microorganisms) were the largest in the absence of particles. The amount of biofilm bacterial and the fluorescence intensity of EPS both showed first an increasing and then decreasing trend with particle concentration increasing. When particle concentration was relatively low, the absorption of particles and bacteria played a major role, however, with the increasing particle concentration, more stable particle–particle were formed and thus, EPS was easily extracted, resulting in the increase of fluorescence intensity of EPS.
41
Lauro, Federico M., Khiem Tran, Alessandro Vezzi, Nicola Vitulo, Giorgio Valle e Douglas H. Bartlett. "Large-Scale Transposon Mutagenesis of Photobacterium profundum SS9 Reveals New Genetic Loci Important for Growth at Low Temperature and High Pressure". Journal of Bacteriology 190, n. 5 (21 dicembre 2007): 1699–709. http://dx.doi.org/10.1128/jb.01176-07.
Abstract (sommario):
ABSTRACT Microorganisms adapted to piezopsychrophilic growth dominate the majority of the biosphere that is at relatively constant low temperatures and high pressures, but the genetic bases for the adaptations are largely unknown. Here we report the use of transposon mutagenesis with the deep-sea bacterium Photobacterium profundum strain SS9 to isolate dozens of mutant strains whose growth is impaired at low temperature and/or whose growth is altered as a function of hydrostatic pressure. In many cases the gene mutation-growth phenotype relationship was verified by complementation analysis. The largest fraction of loci associated with temperature sensitivity were involved in the biosynthesis of the cell envelope, in particular the biosynthesis of extracellular polysaccharide. The largest fraction of loci associated with pressure sensitivity were involved in chromosomal structure and function. Genes for ribosome assembly and function were found to be important for both low-temperature and high-pressure growth. Likewise, both adaptation to temperature and adaptation to pressure were affected by mutations in a number of sensory and regulatory loci, suggesting the importance of signal transduction mechanisms in adaptation to either physical parameter. These analyses were the first global analyses of genes conditionally required for low-temperature or high-pressure growth in a deep-sea microorganism.
42
Zheng, Xiao-Chuan, Hong-Shan Li, Zi-Han Wang, Zhong-Fang Sun e Lei Zhao. "Intermediates Production in Methane Oxidation Coupled with Denitrification: Current Status, Challenges, and Future Opportunities". Fermentation 9, n. 7 (9 luglio 2023): 645. http://dx.doi.org/10.3390/fermentation9070645.
Abstract (sommario):
Climate warming is a hot environmental issue of global concern. As one of the major methane sinks, the process of methane oxidation coupled with denitrification (MOD) reduces the environmental impact brought by the greenhouse effect and water eutrophication. In addition, as an energy substance, methane can also improve its economic value by transforming into other liquid chemicals. Previous studies on the mechanism of the process have mainly focused on the extracellular electron transfer between species. However, in recent years, the production of intermediates influenced by different factors, and the existence of a large number of acid-producing bacteria and methanogens under anaerobic conditions, has led some researchers to pursue research into a new mechanism of the process. Moreover, the discovery of CO2 as a potential electron acceptor in products is certainly exciting, being a big opportunity under the ‘carbon neutral’ policy. This review looks back at the development of the MOD process and describes its functional microorganism and mechanism in detail when summarizing the types of microorganisms and intermediates at different oxygen levels, and introduces some traditional and novel biotechnologies, such as metagenomics, meta-transcriptomics, and meta-proteomics, etc., to help explore the novel mechanism of the process of MOD mediated by intermediates.
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Carroll, J. A., T. B. Schmidt, T. R. Callaway, J. G. Wilson e J. R. Donaldson. "Use of a novel oleaginous microorganism as a potential source of lipids for weanling pigs1,2". Translational Animal Science 1, n. 2 (1 aprile 2017): 201–7. http://dx.doi.org/10.2527/tas2017.0023.
Abstract (sommario):
Abstract Weanling pigs are at risk of succumbing to illness due to an immature immune system and insufficient supply of available energy at the time of weaning. This study was aimed at determining whether oleaginous bacteria could serve as a source of lipids to weanling pigs. Weanling pigs were provided a daily dose of 1×109 colony fomring unit (CFU) = kg−1 of the novel oleaginous Enterobacter cloacae strain JD6301 or JD8715 (which is a variant form of JD6301 capable of producing extracellular triglycerides) via oral gavage for 5 d. Serum was collected every 6 h and intestinal samples were collected at 6 d. Providing pigs with JD6301 or JD8715 significantly increased serum concentrations of triglycerides and non-esterified fatty acids (NEFA) within 72 h. Additionally, the JD6301 and JD8715 strains were able to survive within the gastrointestinal tract throughout the duration of the study. These results suggest that providing Enterobacter cloacae can increase the serum lipids in the pigs, thus potentially providing an additional source of energy to animals during times of stress. This could potentially help improve the metabolic response of animals during times of stress.
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Vinchurkar, Urjita, Palak Modi, Anvi Piludariya, Yogita Mistry, Gunvant Parmar e Summaiya Mullan. "INVITRO DETECTION OF BIOFILM PRODUCED BY MICROORGANISM ISOLATED FROM PATIENTS OF PERIODONTITIS". International Journal of Advanced Research 11, n. 02 (28 febbraio 2023): 823–28. http://dx.doi.org/10.21474/ijar01/16316.
Abstract (sommario):
Introduction:Periodontal infections, including gingivitis and periodontitis, form a major group among the most encountered chronic diseases with infective etiologies. Microorganisms present in gingival sulcus around teeth form microbial biofilm, which is most important cause of periodontal diseases. Biofilm, a three-dimensional (3D) microbial structure with cells enclosed within a self-produced extracellular matrix that may be attached to a substratum comprises the structure of a biofilm. This study aims to detect biofilm in microorganisms isolated from periodontal pockets and establishment of relation between biofilm with tobacco chewing and comorbidies. Material and methods:Total 100 Patients samples were collected using bent swab from periodontal lesions. Samples were processed aerobically and identification of the isolates were done along with simultaneous demonstration of in vitro biofilm formation. Results:Biofilm production was detected by using pre sterilized 96 well polystyrene micro titer plates. 71 samples were shown growth of microorganisms like Streptococcus viridians (36), Klebsiella pneumoniae (21), E. coli (6), Klebsiella oxytoca (4), Acinetobacter baumannii (1), Pseudomonas aeruginosa (1), Staphylococcus aureus (1), and Coagulase negative staphylococcus (1).19 isolates of Streptococcus viridians had formed biofilm out of 36 isolates. 16 isolates of Klebsiella pneumoniae had formed biofilm out of 21 isolates. 3 isolates of Klebsiella oxytoca had formed biofilm out of total 4 isolates. 2 isolates of E. coli had formed biofilm out of 6 isolates. One isolate, each of Acinetobacter baumannii, CONS and Pseudomonas aeroginosahad formed biofilm. Discussion: Out of 43 positive oral biofilms, 21% were tobacco chewers and out of negative oral biofilm, 15% were tobacco chewers. Among positive oral biofilms, 19% had co morbidities and among negative oral biofilm, 15% had co morbidity. Conclusion:The oral colonization by biofilm producing strains can also increase the risk of their dissemination to various human tissues and organs. Apart from that, biofilms cause resistance to many antimicrobial agents.
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Ehlers, G. A. C., e S. J. Turner. "Evaluation of extracellular biopolymer and its impact on bioflocculation in activated sludge bioreactors". Water Science and Technology 63, n. 4 (1 febbraio 2011): 689–94. http://dx.doi.org/10.2166/wst.2011.112.
Abstract (sommario):
The influence and dynamics of bacterial extracellular polysaccharide (EPS) polymer production and its impact on bioflocculation in activated sludge (AS) bench-scale reactors were investigated. The impact of food to microorganism ratio (F/M), reactor configuration and easily biodegradable carbohydrates in influent streams on biological processes that support or weaken good floc formation and the link with EPS quantity was studied. Bioreactors were run as either sequencing batch or continuous systems using wastewater media with glucose or acetate as C source in different F/M ratios. EPS levels were quantified using mid-infrared spectroscopy which provided a rapid technique for monitoring biological processes within AS WWTP. The analysis revealed an interdependent link between EPS production, sludge settling characteristics and mode of reactor operation. An inverse relationship between F/M ratios and EPS quantities was seen but a positive link between EPS levels and aggregation indices, a measure of the efficiency of inter cell attachment and which indicates good settling properties, was also seen. This indicates that during high F/M conditions in lab-scale AS reactors, low levels of EPS may be produced which could have a negative impact on settling of the biomass. Floc architecture was examined under the microscope. Transient growth of filamentous bacteria was seen in the reactors.
46
Bhattacharya, Sarbani, Victoria A. Ploplis e Francis J. Castellino. "Bacterial Plasminogen Receptors Utilize Host Plasminogen System for Effective Invasion and Dissemination". Journal of Biomedicine and Biotechnology 2012 (2012): 1–19. http://dx.doi.org/10.1155/2012/482096.
Abstract (sommario):
In order for invasive pathogens to migrate beyond the site of infection, host physiological barriers such as the extracellular matrix, the basement membrane, and encapsulating fibrin network must be degraded. To circumvent these impediments, proteolytic enzymes facilitate the dissemination of the microorganism. Recruitment of host proteases to the bacterial surface represents a particularly effective mechanism for enhancing invasiveness. Plasmin is a broad spectrum serine protease that degrades fibrin, extracellular matrices, and connective tissue. A large number of pathogens express plasminogen receptors which immobilize plasmin(ogen) on the bacterial surface. Surface-bound plasminogen is then activated by plasminogen activators to plasmin through limited proteolysis thus triggering the development of a proteolytic surface on the bacteria and eventually assisting the spread of bacteria. The host hemostatic system plays an important role in systemic infection. The interplay between hemostatic processes such as coagulation and fibrinolysis and the inflammatory response constitutes essential components of host defense and bacterial invasion. The goal of this paper is to highlight mechanisms whereby pathogenic bacteria, by engaging surface receptors, utilize and exploit the host plasminogen and fibrinolytic system for the successful dissemination within the host.
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Paravastu, Venkata Kamala Kumari, e G. Girija Sankar. "L-ASPARAGINASE ENZYME PRODUCTION FROM MARINE FUNGUS BEAUVERIA BASSIANA – STATISTICAL OPTIMIZATION". INDIAN DRUGS 60, n. 08 (28 agosto 2023): 38–44. http://dx.doi.org/10.53879/id.60.08.13301.
Abstract (sommario):
Statistical optimization was done to enhance the production of L-asparaginase by submerged fermentation from the marine fungus Beauveria bassiana, which was isolated from sediments and corals of sea. Optimization of different process parameters for the production of L-asparaginase and validation using response surface methodology involving central composite design (CCD) was performed with four variables, carbon source, nitrogen source which are essentially important for the growth of the microorganism and other conditions like pH and inoculum level, which include dextrose at 0.43% w/V, L-asparagine 1.1%w/V, pH 7.5 and an inoculum level of 10.2% w/V, respectively. Extracellular production of L-asparaginase by B. bassiana and its potential for L-asparaginase production is reported in the present study.
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Neha Sharma, Shuchi Kaushik e Rajesh Singh Tomar. "Prediction of the allergic response of extracellular amylase producing bacteria through in-silico method". International Journal of Research in Pharmaceutical Sciences 10, n. 2 (14 aprile 2019): 1185–89. http://dx.doi.org/10.26452/ijrps.v10i2.404.
Abstract (sommario):
Allergies intolerance is a common problem worldwide. The major difficulties are related to the correct diagnosis of causes which is associated with amino acid sequences present in the epitope region of allergen. So there is a need to find out the factors causing allergies and allergens themselves. In the present study a bioinformatics tool is used to predict amino acid sequence and mast cell association with different integrated approaches. Internet databases for amylase producing bacteria were used in In-silico method to check the allergy for microorganism producing the extracellular enzyme. Amylase is an extracellular enzyme isolated from soil bacteria Salmonella species and Proteus vulgaris. It is very important in the pharmaceutical industry to check the allergenicity of any drug, protein or enzyme that be used in the treatment of diseases or food industries for various purpose. The aim of the present study is isolation and characterisation of extracellular enzyme produced from soil bacteria and to analyzed allergic response through AlgPred tool of bioinformatics. From results, it was concluded that the protein sequence of amylase did not contain any epitope, no hits for mast and blast which proved that it was not an allergen. So, bacterial isolates from the industrial soil are a good alternative source of enzyme production and may be used as an industrial level. Thus, from the results, it may be concluded that microbes from soil sample can be a good source of industrially important enzymes without any allergy.
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Horváth, Judit, Bence Mátyás e János Kátai. "Effect of agrotechnical factors on the activity of urease enzyme in a long term fertlization experiment". Acta Agraria Debreceniensis, n. 68 (18 febbraio 2016): 43–48. http://dx.doi.org/10.34101/actaagrar/68/1768.
Abstract (sommario):
The soil is a natural resource, the fertility preservation is an important part of the sustainable development. We have to monitor the transformation dinamics of the organic nitrogen-containing substances, to get accurate information about the changes of the nitrogen cycle in the soil.
Physical and chemical properties of the soil and the microorganism effect on the organic matter in the soil – in addition to the composition of organic matter. Wide variety of extracellular enzymes are present in this decomposition. These enzymes help in the transformation of the macromolecules to transforming low molecular weight compounds so they will be available during the assimilation.
The urease enzyme, catalyzes the hydrolysis of urea to CO2 and NH3. The urease is widely spread in the nature, it is present in the microorganisms, plants and animals.
We found that the soil moisture content, the rotation and the fertilization affect to the amount of urease in spring. Furthermore, we get significant difference between the irrigated and non irrigated samples in the second period of the year. Based on our results we can state that the activity of urease was higher in spring 2014.
The objective of our study was to present how the different agronomic factors affect on the activity of urease in a long term fertilizationexperiment.
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Raffaelli, Sofía, Eduardo Abreo, Nora Altier, Álvaro Vázquez e Silvana Alborés. "Bioprospecting the Antibiofilm and Antimicrobial Activity of Soil and Insect Gut Bacteria". Molecules 27, n. 6 (21 marzo 2022): 2002. http://dx.doi.org/10.3390/molecules27062002.
Abstract (sommario):
Antimicrobial resistance is a growing concern in public health and current research shows an important role for bacterial biofilms in recurrent or chronic infections. New strategies, therefore, are necessary to overcome antimicrobial resistance, through the development of new therapies that could alter or inhibit biofilm formation. In this sense, antibiofilm natural products are very promising. In this work, a bioprospection of antimicrobial and antibiofilm extracts from Uruguayan soil bacteria and insect gut bacteria was carried out. Extracts from extracellular broths were tested for their ability to inhibit planktonic cell growth and biofilm formation. Genomic analysis of Bacillus cereus ILBB55 was carried out. All extracts were able to inhibit the growth of, at least, one microorganism and several extracts showed MICs lower than 500 µg mL−1 against microorganisms of clinical relevance (Staphylococcus aureus, Pseudomonas aeruginosa, and Enterobacter cloacae). Among the extracts evaluated for biofilm inhibition only ILBB55, from B. cereus, was able to inhibit, S. aureus (99%) and P. aeruginosa (62%) biofilms. Genomic analysis of this strain showed gene clusters similar to other clusters that code for known antimicrobial compounds. Our study revealed that extracts from soil bacteria and insect gut bacteria, especially from B. cereus ILBB55, could be potential candidates for drug discovery to treat infectious diseases and inhibit S. aureus and P. aeruginosa biofilms.