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Abdul Nabi, Y. Z. Ahmed, A. N. Jatt, S. A. Tunio, A. S. Qureshi, S. B. Memon e S. M. Abbassi. "INVESTIGATION OF N-ACYL HOMOSERINE LACTONE-BASED QUORUM-SENSING SYSTEM AND ALIGINATE LYASE ACTIVITY IN MARINE BACTERIAL SPECIES OF GRIMONTIA MARINA AS01 AND ALTEROMONAS MACLEODII AS02". Pakistan Journal of Science 74, n. 1-1 (27 marzo 2023): 25–31. http://dx.doi.org/10.57041/pjs.v74i1-1.905.
Testo completoAbstract (sommario):
Production, detection, and reaction to external signaling molecules are essential steps in quorum sensing (QS) process. Through the use of QS, bacterial communities may synchronize their responses to shifts in the density and diversity of their vicinal neighbors. QS also play an important role in regulating enzmyatic activities among marine bacteria. The aim of the present study was to detect and identify N- acyl homoserine lactones (AHLs) based QS signaling molecules and the possible influence on alginate lyase in marine bacterial isolates of Grimontia marina AS01 and Alteromonas macleodi AS02. Marine water samples were collected from Arabian Sea, Karchi Pakistan, following the standard collection methods. Bacterial strains were isolated and pure cultured using Zobell 2216 marine medium. Molecular identification was achieved based on 16S rRNA gene analysis. Screening for AHLs was achieved using Agrobacterium tumefaciens A136 as a biosensor. Based on 16S rRNA analysis, the bacterial strains were identified as Grimontia marina strain AS01 (OP143768) and Alteromonas macleodii strain AS02 (OP143769). Cross-feeding bioassay revealed the positive reactions for the production of AHLs. Reversed phase-TLC analysis showed the identification of C6-HSL produced by G. marina AS01 and 3OXO-C6-HSL by A. macleodii AS02 strain. Moreover, QS inhibitor AiiA protein reduced the production of alginate lyase in A. macleodi AS02, while no effect was observed in G. marina AS01. These results substantiate the involvement of QS system in regulating alginate lyase activity in A. macleodii AS02. QS in marine bacteria may involve in hydrolysis of complex organic matter in marine environment.
2
Jeganathan, P., K. M. Rajasekaran, N. K. Asha Devi e S. Karuppusamy. "Antimicrobial activity and Characterization of Marine bacteria". Indian Journal of Pharmaceutical and Biological Research 1, n. 04 (31 dicembre 2013): 38–44. http://dx.doi.org/10.30750/ijpbr.1.4.8.
Testo completoAbstract (sommario):
Marine bacteria were isolated from seawater was collected from different coastal areas of the Tamilnadu Sea. The antimicrobial activities of these bacteria were investigated. Ethyl acetate extracts of marine bacterial fermentation were screened for antimicrobial activities using the method of agar diffusion. The results showed that 25 strains of the isolates have antimicrobial activity. The proportion of active bacteria associated with isolated from seawater. The active marine bacteria were assigned to the genera Alteromonas, Pseudomonas, Bacillus and Marinobacter. The TLC autobiographic overlay assay implied that the antimicrobial metabolites produced by four strains with wide antimicrobial spectrum were different. These marine bacteria were expected to be potential resources of natural antibiotic products. It can be concluded that isolation of Marine bacterial samples can offer a numbers of microbial strains for sources of new biomolecules from Marine sources.
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Hopkinson, Brian M., Kelly L. Roe e Katherine A. Barbeau. "Heme Uptake by Microscilla marina and Evidence for Heme Uptake Systems in the Genomes of Diverse Marine Bacteria". Applied and Environmental Microbiology 74, n. 20 (29 agosto 2008): 6263–70. http://dx.doi.org/10.1128/aem.00964-08.
Testo completoAbstract (sommario):
ABSTRACT The ability to acquire diverse and abundant forms of iron would be expected to confer a survival advantage in the marine environment, where iron is scarce. Marine bacteria are known to use siderophores and inorganic iron, but their ability to use heme, an abundant intracellular iron form, has only been examined preliminarily. Microscilla marina, a cultured relative of a bacterial group frequently found on marine particulates, was used as a model organism to examine heme uptake. Searches of the genome revealed analogs to known heme transport proteins, and reverse transcription-quantitative PCR analysis of these genes showed that they were expressed and upregulated under iron stress and during growth on heme. M. marina was found to take up heme-bound iron and could grow on heme as a sole iron source, supporting the genetic evidence for heme transport. Similar putative heme transport components were identified in the genomes of diverse marine bacteria. These systems were found in the genomes of many bacteria thought to be particle associated but were lacking in known free-living organisms (e.g., Pelagibacter ubique and marine cyanobacteria). This distribution of transporters is consistent with the hydrophobic, light-sensitive nature of heme, suggesting that it is primarily available on phytoplankton or detritus or in nutrient-rich environments.
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Borges, Anabela, e Manuel Simões. "Quorum Sensing Inhibition by Marine Bacteria". Marine Drugs 17, n. 7 (23 luglio 2019): 427. http://dx.doi.org/10.3390/md17070427.
Testo completoAbstract (sommario):
Antibiotic resistance has been increasingly reported for a wide variety of bacteria of clinical significance. This widespread problem constitutes one of the greatest challenges of the twenty-first century. Faced with this issue, clinicians and researchers have been persuaded to design novel strategies in order to try to control pathogenic bacteria. Therefore, the discovery and elucidation of the mechanisms underlying bacterial pathogenesis and intercellular communication have opened new perspectives for the development of alternative approaches. Antipathogenic and/or antivirulence therapies based on the interruption of quorum sensing pathways are one of several such promising strategies aimed at disarming rather than at eradicating bacterial pathogens during the course of colonization and infection. This review describes mechanisms of bacterial communication involved in biofilm formation. An overview of the potential of marine bacteria and their bioactive components as QS inhibitors is further provided.
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Satishbabu, Kakumanu, e Prasuna Ravi Gyana. "A study to determine effect of metal ions for optimization of L-Asparaginase producers for bioprocessing". Research Journal of Biotechnology 18, n. 9 (15 agosto 2023): 88–97. http://dx.doi.org/10.25303/1809rjbt088097.
Testo completoAbstract (sommario):
The present study encompasses isolation of marine bacteria from marine soil samples collected from Chirala, Coastal area of Andhra Pradesh. Work includes isolation, screening, morphological and molecular characterization of selected L- Asparaginase producers. Purified enzyme was used for enzyme kinetic studies. Marine soil sample was collected in sterile bottle and brought to the lab bench and a total of 12 morphologically distinct bacterial colonies were isolated from collected marine soil samples and coded as Chirala Marine Bacteria. All 12 Chirala Marine Bacteria isolates were qualitatively screened for L-Asparaginase production. Out of 12 Chirala marine bacteria isolates, 9 isolates show positive response to L-Asparaginase activity. Effect of inducers i.e. carbon, nitrogen, aminoacids, phosphates and metal ions was studied.
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Lee, Yoo Kyung, Kae Kyoung Kwon, Kyeung Hee Cho, Jae Hyun Park e Hong Kum Lee. "Isolation and Identification of Bacteria from Marine Biofilms". Key Engineering Materials 277-279 (gennaio 2005): 612–17. http://dx.doi.org/10.4028/www.scientific.net/kem.277-279.612.
Testo completoAbstract (sommario):
In the marine environment, biofilms cover most of the subtidal and intertidal solid surfaces. Culturable bacteria forming marine biofilms were isolated on artificial substrate called acrylic coupons. The bacterial isolates were identified through a comparison of 16S rDNA sequences. A total of 115 strains were cultured and identified, 45 of which showed the same sequences with other strains. Therefore, 70 strains were finally identified. The bacterial isolates belonged to a–Proteobacteria (32 isolates), g–Proteobacteria (12 isolates), CFB group bacteria (4 isolates), high GC Gram-positive bacteria (9 isolates), and low GC Gram-positive bacteria (13 isolates). The bacterial isolates may be used as standard bacteria to test new antifouling agent. They may also be utilized as useful bacteria to enhance the settlement of commercial algae and invertebrate larvae for aquaculture.
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Kim, Hyo-Ryeon, Jae-Hyun Lim, Ju-Hyoung Kim e Il-Nam Kim. "Collection of Environmental Variables and Bacterial Community Compositions in Marian Cove, Antarctica, during Summer 2018". Data 6, n. 3 (5 marzo 2021): 27. http://dx.doi.org/10.3390/data6030027.
Testo completoAbstract (sommario):
Marine bacteria, which are known as key drivers for marine biogeochemical cycles and Earth’s climate system, are mainly responsible for the decomposition of organic matter and production of climate-relevant gases (i.e., CO₂, N₂O, and CH₄). However, research is still required to fully understand the correlation between environmental variables and bacteria community composition. Marine bacteria living in the Marian Cove, where the inflow of freshwater has been rapidly increasing due to substantial glacial retreat, must be undergoing significant environmental changes. During the summer of 2018, we conducted a hydrographic survey to collect environmental variables and bacterial community composition data at three different layers (i.e., the seawater surface, middle, and bottom layers) from 15 stations. Of all the bacterial data, 17 different phylum level bacteria and 21 different class level bacteria were found and Proteobacteria occupy 50.3% at phylum level following Bacteroidetes. Gammaproteobacteria and Alphaproteobacteria, which belong to Proteobacteria, are the highest proportion at the class level. Gammaproteobacteria showed the highest relative abundance in all three seawater layers. The collection of environmental variables and bacterial composition data contributes to improving our understanding of the significant relationships between marine Antarctic regions and marine bacteria that lives in the Antarctic.
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Long, Richard A., e Farooq Azam. "Antagonistic Interactions among Marine Pelagic Bacteria". Applied and Environmental Microbiology 67, n. 11 (1 novembre 2001): 4975–83. http://dx.doi.org/10.1128/aem.67.11.4975-4983.2001.
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ABSTRACT Recent studies suggest that bacterial abundance and species diversity in the ocean's water column are variable at the millimeter scale, apparently in response to the small-scale heterogeneity in the distribution of organic matter. We hypothesized that bacterium-bacterium antagonistic interactions may contribute to variations in community structure at the microscale. We examined each of the 86 isolates for their inhibition of growth of the remaining 85 isolates by the Burkholder agar diffusion assay. More than one-half of the isolates expressed antagonistic activity, and this trait was more common with particle-associated bacteria than with free-living bacteria. This was exemplified by members of the α subclass of the class Proteobacteria (α-proteobacteria), in which production of antagonistic molecules was dominated by attached bacteria. We found that γ-proteobacteria (members of the ordersAlteromonadales and Vibrionales) are the most prolific producers of inhibitory materials and also the most resilient to them, while members of the Bacteriodetes were the organisms that were least productive and most sensitive to antagonistic interactions. Widespread interspecies growth inhibition is consistent with the role of this phenomenon in structuring bacterial communities at the microscale. Furthermore, our results suggest that bacteria from pelagic marine particles may be an underutilized source of novel antibiotics.
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Pathiraja, Pathiraja Mudiyanselage Duleepa, e In-Geol Choi. "해양 종속영양세균의 한천대사에 대한 새로운 통찰". Institute of Life Science and Natural Resources 30 (31 dicembre 2022): 53–65. http://dx.doi.org/10.33147/lsnrr.2022.30.1.53.
Testo completoAbstract (sommario):
Agar is a key structural polysaccharide of red macroalgae which provides a rich habitat for marine heterotrophic bacteria in marine ecosystems. Marine agarolytic bacteria, that can use agar as the sole carbon source, are distributed in diverse marine environments from open coastal waters to the gut of marine herbivores. Agarolytic bacteria employ a combination of carbohydrate-active enzymes (CAZymes) for the depolymerization of agar. Extensive studies on the genomic architecture of the agarolytic bacteria suggested that genes encoding these CAZymes are arranged in polysaccharide utilization loci (PUL). Agar hydrolyzing enzymes (agarases) are categorized into; β-agarase (GH16, GH50, GH86, and GH118), α-agarase (GH96), neoagarooligosaccharide hydrolase (GH117), and agarolytic β-galactosidase (GH2). The molecular functionality, structural elements, and catalytic mechanisms of agarases belonging to different GH families show unique characteristics. L-AHG, one of the main constituents in agar, is a rare monosaccharide and its metabolic pathway is exclusively found in marine agarolytic bacteria. Recent trends in the agarolytic systems are mostly focused on the sequence data to visualize the universal agarolytic enzyme repertoire and the evolution of the agarolytic pathway in marine heterotrophic bacteria. In addition, increasing attention is paid to understanding the oligosaccharide transport mechanisms and transcriptional regulation of genes in PUL. In this review, we will cover a comprehensive overview of genomic architecture, structural and functional analysis of agar hydrolyzing enzymes, and agar metabolism in marine heterotrophic bacteria.
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Zhao, Jing, Xinyun Li, Xiyan Hou, Chunshan Quan e Ming Chen. "Widespread Existence of Quorum Sensing Inhibitors in Marine Bacteria: Potential Drugs to Combat Pathogens with Novel Strategies". Marine Drugs 17, n. 5 (8 maggio 2019): 275. http://dx.doi.org/10.3390/md17050275.
Testo completoAbstract (sommario):
Quorum sensing (QS) is a phenomenon of intercellular communication discovered mainly in bacteria. A QS system consisting of QS signal molecules and regulatory protein components could control physiological behaviors and virulence gene expression of bacterial pathogens. Therefore, QS inhibition could be a novel strategy to combat pathogens and related diseases. QS inhibitors (QSIs), mainly categorized into small chemical molecules and quorum quenching enzymes, could be extracted from diverse sources in marine environment and terrestrial environment. With the focus on the exploitation of marine resources in recent years, more and more QSIs from the marine environment have been investigated. In this article, we present a comprehensive review of QSIs from marine bacteria. Firstly, screening work of marine bacteria with potential QSIs was concluded and these marine bacteria were classified. Afterwards, two categories of marine bacteria-derived QSIs were summarized from the aspects of sources, structures, QS inhibition mechanisms, environmental tolerance, effects/applications, etc. Next, structural modification of natural small molecule QSIs for future drug development was discussed. Finally, potential applications of QSIs from marine bacteria in human healthcare, aquaculture, crop cultivation, etc. were elucidated, indicating promising and extensive application perspectives of QS disruption as a novel antimicrobial strategy.
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Anteneh, Yitayal S., Qi Yang, Melissa H. Brown e Christopher M. M. Franco. "Antimicrobial Activities of Marine Sponge-Associated Bacteria". Microorganisms 9, n. 1 (14 gennaio 2021): 171. http://dx.doi.org/10.3390/microorganisms9010171.
Testo completoAbstract (sommario):
The misuse and overuse of antibiotics have led to the emergence of multidrug-resistant microorganisms, which decreases the chance of treating those infected with existing antibiotics. This resistance calls for the search of new antimicrobials from prolific producers of novel natural products including marine sponges. Many of the novel active compounds reported from sponges have originated from their microbial symbionts. Therefore, this study aims to screen for bioactive metabolites from bacteria isolated from sponges. Twelve sponge samples were collected from South Australian marine environments and grown on seven isolation media under four incubation conditions; a total of 1234 bacterial isolates were obtained. Of these, 169 bacteria were tested in media optimized for production of antimicrobial metabolites and screened against eleven human pathogens. Seventy bacteria were found to be active against at least one test bacterial or fungal pathogen, while 37% of the tested bacteria showed activity against Staphylococcus aureus including methicillin-resistant strains and antifungal activity was produced by 21% the isolates. A potential novel active compound was purified possessing inhibitory activity against S. aureus. Using 16S rRNA, the strain was identified as Streptomyces sp. Our study highlights that the marine sponges of South Australia are a rich source of abundant and diverse bacteria producing metabolites with antimicrobial activities against human pathogenic bacteria and fungi.
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Benhadda, Fanny, Agata Zykwinska, Sylvia Colliec-Jouault, Corinne Sinquin, Bertrand Thollas, Anthony Courtois, Nicola Fuzzati, Alix Toribio e Christine Delbarre-Ladrat. "Marine versus Non-Marine Bacterial Exopolysaccharides and Their Skincare Applications". Marine Drugs 21, n. 11 (7 novembre 2023): 582. http://dx.doi.org/10.3390/md21110582.
Testo completoAbstract (sommario):
Bacteria are well-known to synthesize high molecular weight polysaccharides excreted in extracellular domain, which constitute their protective microenvironment. Several bacterial exopolysaccharides (EPS) are commercially available for skincare applications in cosmetic products due to their unique structural features, conferring valuable biological and/or textural properties. This review aims to give an overview of bacterial EPS, an important group of macromolecules used in cosmetics as actives and functional ingredients. For this purpose, the main chemical characteristics of EPS are firstly described, followed by the basics of the development of cosmetic ingredients. Then, a focus on EPS production, including upstream and downstream processes, is provided. The diversity of EPS used in the cosmetic industry, and more specifically of marine-derived EPS is highlighted. Marine bacteria isolated from extreme environments are known to produce EPS. However, their production processes are highly challenging due to high or low temperatures; yield must be improved to reach economically viable ingredients. The biological properties of marine-derived EPS are then reviewed, resulting in the highlight of the challenges in this field.
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Li, Chun-Yang, Xiu-Lan Chen, Qi-Long Qin, Peng Wang, Wei-Xin Zhang, Bin-Bin Xie, Hai-Nan Su, Xi-Ying Zhang, Bai-Cheng Zhou e Yu-Zhong Zhang. "Structural Insights into the Multispecific Recognition of Dipeptides of Deep-Sea Gram-Negative Bacterium Pseudoalteromonas sp. Strain SM9913". Journal of Bacteriology 197, n. 6 (20 gennaio 2015): 1125–34. http://dx.doi.org/10.1128/jb.02600-14.
Testo completoAbstract (sommario):
ABSTRACTPeptide uptake is important for nutrition supply for marine bacteria. It is also an important step in marine nitrogen cycling. However, how marine bacteria absorb peptides is still not fully understood. DppA is the periplasmic dipeptide binding protein of dipeptide permease (Dpp; an important peptide transporter in bacteria) and exclusively controls the substrate specificity of Dpp. Here, the substrate binding specificity of deep-seaPseudoalteromonassp. strain SM9913 DppA (PsDppA) was analyzed for 25 different dipeptides with various properties by using isothermal titration calorimetry measurements.PsDppA showed binding affinities for 8 dipeptides. To explain the multispecific substrate recognition mechanism ofPsDppA, we solved the crystal structures of unligandedPsDppA and ofPsDppA in complex with 4 different types of dipeptides (Ala-Phe, Met-Leu, Gly-Glu, and Val-Thr).PsDppA alternates between an “open” and a “closed” form during substrate binding. Structural analyses of the 4PsDppA-substrate complexes combined with mutational assays indicate thatPsDppA binds to different substrates through a precise mechanism: dipeptides are bound mainly by the interactions between their backbones andPsDppA, in particular by anchoring their N and C termini through ion-pair interactions; hydrophobic interactions are important in binding hydrophobic dipeptides; and Lys457 is necessary for the binding of dipeptides with a C-terminal glutamic acid or glutamine. Additionally, sequence alignment suggests that the substrate recognition mechanism ofPsDppA may be common in Gram-negative bacteria. All together, our results provide structural insights into the multispecific substrate recognition mechanism of marine Gram-negative bacterial DppA, which provides a better understanding of the mechanisms of marine bacterial peptide uptake.IMPORTANCEPeptide uptake plays a significant role in nutrition supply for marine bacteria. It is also an important step in marine nitrogen cycling. However, how marine bacteria recognize and absorb peptides is still unclear. This study analyzed the substrate binding specificity of deep-seaPseudoalteromonassp. strain SM9913 DppA (PsDppA; the dipeptide-binding protein of dipeptide permease) and solved the crystal structures of unligandedPsDppA andPsDppA in complex with 4 different types of dipeptides. The multispecific recognition mechanism ofPsDppA for dipeptides is explained based on structural and mutational analyses. We also find that the substrate-binding mechanism ofPsDppA may be common in Gram-negative bacteria. This study sheds light on marine Gram-negative bacterial peptide uptake and marine nitrogen cycling.
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Schultz, Gary E., e Peter H. Santschi. "Effect of the Added Acyl Homoserine Lactones on Separated Free-Living Marine Bacteria as a Model of Quorum Sensing". Journal of Marine Science and Engineering 11, n. 7 (21 giugno 2023): 1258. http://dx.doi.org/10.3390/jmse11071258.
Testo completoAbstract (sommario):
Quorum sensing is a communication system by which bacteria use signal molecules to induce a physiological response. In natural marine environments, quorum sensing is suspected to occur in regions with high cell densities. Free-living bacteria, however, are largely believed to exist at concentrations too low to make use of a density-dependent quorum-sensing system. Due to so-called ‘free-living’ bacteria inhabiting marine gels composed of exopolymeric substances occurring in an operationally defined colloidal fraction, it is possible that quorum-sensing molecules would also occur in this fraction. In this study, possible signaling molecules were collected from marine water, separated, and concentrated as some organic matter. Their identification with an Agrobacterium tumefaciens assay indicated the presence of AHLs. In fall 2002 and spring 2003, free-living (single cells) fraction of marine bacterioplankton was sampled and separated. Various AHLs were added to these disperse populations (109 cells/L). The studied bacterial communities responded with change in the thymidine incorporation. The results are discussed as existence of active reaction of marine free-living bacteria to signaling molecules even in sparse inhabiting marine gels. That there is a bacterial response to signaling molecules in so sparse populations is of great significance for marine and environmental sciences.
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Kogure, Kazuhiro. "Bioenergetics of marine bacteria". Current Opinion in Biotechnology 9, n. 3 (giugno 1998): 278–82. http://dx.doi.org/10.1016/s0958-1669(98)80059-1.
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Cox, Mike. "Fate of marine bacteria". New Scientist 191, n. 2568 (settembre 2006): 22. http://dx.doi.org/10.1016/s0262-4079(06)60414-4.
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Chi, Zhenming, e Yan Fang. "Exopolysaccharides from marine bacteria". Journal of Ocean University of China 4, n. 1 (gennaio 2005): 67–74. http://dx.doi.org/10.1007/s11802-005-0026-2.
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Stonik, V. A., T. N. Makarieva e L. K. Shubina. "Antibiotics from Marine Bacteria". Biochemistry (Moscow) 85, n. 11 (novembre 2020): 1362–73. http://dx.doi.org/10.1134/s0006297920110073.
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Schweder, Thomas, Stephanie Markert e Michael Hecker. "Proteomics of marine bacteria". ELECTROPHORESIS 29, n. 12 (giugno 2008): 2603–16. http://dx.doi.org/10.1002/elps.200800009.
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de Oliveira, Bruno Francesco Rodrigues, e Yahyah Yusuff. "Culturing enigmatic marine bacteria". Nature Microbiology 9, n. 1 (4 gennaio 2024): 6–7. http://dx.doi.org/10.1038/s41564-023-01567-9.
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Andryukov, Boris, Valery Mikhailov e Nataly Besednova. "The Biotechnological Potential of Secondary Metabolites from Marine Bacteria". Journal of Marine Science and Engineering 7, n. 6 (3 giugno 2019): 176. http://dx.doi.org/10.3390/jmse7060176.
Testo completoAbstract (sommario):
Marine habitats are a rich source of molecules of biological interest. In particular, marine bacteria attract attention with their ability to synthesize structurally diverse classes of bioactive secondary metabolites with high biotechnological potential. The last decades were marked by numerous discoveries of biomolecules of bacterial symbionts, which have long been considered metabolites of marine animals. Many compounds isolated from marine bacteria are unique in their structure and biological activity. Their study has made a significant contribution to the discovery and production of new natural antimicrobial agents. Identifying the mechanisms and potential of this type of metabolite production in marine bacteria has become one of the noteworthy trends in modern biotechnology. This path has become not only one of the most promising approaches to the development of new antibiotics, but also a potential target for controlling the viability of pathogenic bacteria.
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Monika, Siska, Dessy Yoswaty e Nursyirwani Nursyirwani. "TEST THE ABILITY OF SEDIMENT BACTERIA ISOLATES IN DEGRADATING PHENOL". Asian Journal of Aquatic Sciences 2, n. 1 (10 gennaio 2020): 79–84. http://dx.doi.org/10.31258/ajoas.2.1.79-84.
Testo completoAbstract (sommario):
Phenol degrading bacteria can be found in various habitats in marine environments. This study aims to obtain bacteria from sediments that are able to degrade phenol. The process of bacterial purification and degradation was carried out from August to September 2018 at the Marine Microbiology Laboratory, Department of Marine Sciences, Faculty of Fisheries and Marine, University of Riau. Analysis of the reduction in phenol concentration was carried out using the APHA 5530 method using UV-VIS spectrophotometry conducted at the Health and Environment Laboratory. The bacterial isolates used as test bacteria were isolates BF1A, BF4B and BF9C. Bacterial and biochemical tests were carried out for all bacterial isolates. Two isolated showed mehyl red negative, all isolates were motile. Three isolates were positive catalase, able to ferment glucose and sucrose fermented citrate and two isolat were Gram negative bacterial. The three bacterial isolates were able to degrade phenol with the highest degradation for 1ppm shown in isolates BF1A, the highest degradation of concentrations of 2 ppm and 3 ppm was shown in isolates BF9C. Thus, the isolat BF9C was able to degrade the highest phenol.
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Tran, Nhan-An T., Bojan Tamburic, Christian R. Evenhuis e Justin R. Seymour. "Bacteria-mediated aggregation of the marine phytoplankton Thalassiosira weissflogii and Nannochloropsis oceanica". Journal of Applied Phycology 32, n. 6 (30 settembre 2020): 3735–48. http://dx.doi.org/10.1007/s10811-020-02252-8.
Testo completoAbstract (sommario):
AbstractThe ecological relationships between heterotrophic bacteria and marine phytoplankton are complex and multifaceted, and in some instances include the bacteria-mediated aggregation of phytoplankton cells. It is not known to what extent bacteria stimulate aggregation of marine phytoplankton, the variability in aggregation capacity across different bacterial taxa or the potential role of algogenic exopolymers in this process. Here we screened twenty bacterial isolates, spanning nine orders, for their capacity to stimulate aggregation of two marine phytoplankters, Thalassiosira weissflogii and Nannochloropsis oceanica. In addition to phytoplankton aggregation efficiency, the production of exopolymers was measured using Alcian Blue. Bacterial isolates from the Rhodobacterales, Flavobacteriales and Sphingomonadales orders stimulated the highest levels of cell aggregation in phytoplankton cultures. When co-cultured with bacteria, exopolymer concentration accounted for 34.1% of the aggregation observed in T. weissflogii and 27.7% of the aggregation observed in N. oceanica. Bacteria-mediated aggregation of phytoplankton has potentially important implications for mediating vertical carbon flux in the ocean and in extracting phytoplankton cells from suspension for biotechnological applications.
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Cifuentes, Ana, Josefa Antón, Susana Benlloch, Andrew Donnelly, Rodney A. Herbert e Francisco Rodríguez-Valera. "Prokaryotic Diversity in Zostera noltii-Colonized Marine Sediments". Applied and Environmental Microbiology 66, n. 4 (1 aprile 2000): 1715–19. http://dx.doi.org/10.1128/aem.66.4.1715-1719.2000.
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ABSTRACT The diversity of microorganisms present in a sediment colonized by the phanerogam Zostera noltii has been analyzed. Microbial DNA was extracted and used for constructing two 16S rDNA clone libraries for Bacteria and Archaea. Bacterial diversity was very high in these samples, since 57 different sequences were found among the 60 clones analyzed. Eight major lineages of the Domain Bacteria were represented in the library. The most frequently retrieved bacterial group (36% of the clones) was δ-Proteobacteria related to sulfate-reducing bacteria. The second most abundant group (27%) was γ-Proteobacteria, including five clones closely related to S-oxidizing endosymbionts. The archaeal clone library included members of Crenarchaeota and Euryarchaeota, with nine different sequences among the 15 analyzed clones, indicating less diversity when compared to the Bacteria organisms. None of these sequences was closely related to culturedArchaea organisms.
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Pope, Emily, Bradley Haltli, Russell G. Kerr e Ali Ahmadi. "Effects of Matrix Composition and Temperature on Viability and Metabolic Activity of Microencapsulated Marine Bacteria". Microorganisms 10, n. 5 (10 maggio 2022): 996. http://dx.doi.org/10.3390/microorganisms10050996.
Testo completoAbstract (sommario):
To enhance the discovery of novel natural products, various innovations have been developed to aid in the cultivation of previously unculturable microbial species. One approach involving the microencapsulation of bacteria has been gaining popularity as a new cultivation technique, with promising applications. Previous studies demonstrated the success of bacterial encapsulation; however, they highlighted that a key limitation of encapsulating bacteria within agarose is the high temperature required for encapsulation. Encapsulation of bacteria within agarose typically requires a temperature high enough to maintain the flow of agarose through microfluidic devices without premature gelation. Given the sensitivity of many bacterial taxa to temperature, the effect of various agarose-based encapsulating matrices on marine bacterial viability was assessed to further develop this approach to bacterial culture. It was determined that lowering the temperature of encapsulation via the use of low-gelling-temperature agarose, as well as the addition of nutrients to the matrix, significantly improved the viability of representative marine sediment bacteria in terms of abundance and metabolic activity. Based on these findings, the use of low-gelling-temperature agarose with supplemental nutrients is recommended for the encapsulation of marine bacteria obtained from temperate habitats.
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Pinhassi, Jarone, Edward F. DeLong, Oded Béjà, José M. González e Carlos Pedrós-Alió. "Marine Bacterial and Archaeal Ion-Pumping Rhodopsins: Genetic Diversity, Physiology, and Ecology". Microbiology and Molecular Biology Reviews 80, n. 4 (14 settembre 2016): 929–54. http://dx.doi.org/10.1128/mmbr.00003-16.
Testo completoAbstract (sommario):
SUMMARYThe recognition of a new family of rhodopsins in marine planktonic bacteria, proton-pumping proteorhodopsin, expanded the known phylogenetic range, environmental distribution, and sequence diversity of retinylidene photoproteins. At the time of this discovery, microbial ion-pumping rhodopsins were known solely in haloarchaea inhabiting extreme hypersaline environments. Shortly thereafter, proteorhodopsins and other light-activated energy-generating rhodopsins were recognized to be widespread among marine bacteria. The ubiquity of marine rhodopsin photosystems now challenges prior understanding of the nature and contributions of “heterotrophic” bacteria to biogeochemical carbon cycling and energy fluxes. Subsequent investigations have focused on the biophysics and biochemistry of these novel microbial rhodopsins, their distribution across the tree of life, evolutionary trajectories, and functional expression in nature. Later discoveries included the identification of proteorhodopsin genes in all three domains of life, the spectral tuning of rhodopsin variants to wavelengths prevailing in the sea, variable light-activated ion-pumping specificities among bacterial rhodopsin variants, and the widespread lateral gene transfer of biosynthetic genes for bacterial rhodopsins and their associated photopigments. Heterologous expression experiments with marine rhodopsin genes (and associated retinal chromophore genes) provided early evidence that light energy harvested by rhodopsins could be harnessed to provide biochemical energy. Importantly, some studies with native marine bacteria show that rhodopsin-containing bacteria use light to enhance growth or promote survival during starvation. We infer from the distribution of rhodopsin genes in diverse genomic contexts that different marine bacteria probably use rhodopsins to support light-dependent fitness strategies somewhere between these two extremes.
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Megala, B., e P. Thirumalai Vasan. "Diversity of Endophytic Bacteria from Marine Associated Plant Leaves". Indian Journal Of Science And Technology 16, n. 23 (21 giugno 2023): 1726–32. http://dx.doi.org/10.17485/ijst/v16i23.88.
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Taylor, Gordon T., e Jeanne D. Gulnick. "Enhancement of marine bacterial growth by mineral surfaces". Canadian Journal of Microbiology 42, n. 9 (1 settembre 1996): 911–18. http://dx.doi.org/10.1139/m96-117.
Testo completoAbstract (sommario):
The effects of sorptive inert surfaces on growth of marine bacteria and metabolism, as well as partitioning of organic substrates, were examined in microcosms inoculated with bacterioplankton from a local salt marsh. Introduction of organic-free glass beads to a dilute seawater medium (tryptic soy broth) increased yields of ATP, a surrogate for bacterial biomass, by 187% within the entire microcosm (attached + free-living). Growth efficiencies (bacterial C/media C) were 30% for bacteria grown in microcosms with beads compared with 16% without beads. Surface enrichment increased rates of proteolytic enzyme activity and cell-specific [3H]leucine incorporation into protein by factors of 6.8 and 2.2, respectively. Scanning electron microscopy revealed obvious organic coatings on all beads after 2 h of exposure, but few strongly attached bacteria were evident, even after 40 h of exposure. Results support the hypothesis that mineral surfaces facilitate bacterial utilization of complex organic matter through physical–chemical processes that increase conversion efficiencies of labile substrate despite possible kinetic limitations. Furthermore, firm attachment by bacteria to these surfaces is apparently not a requirement to produce surface-enhanced activity.Key words: epibacteria, sorption, interfaces, hydrolytic enzymes, growth efficiency.
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Seymour, Justin R., e Jean-Baptiste Raina. "Swimming in the sea: chemotaxis by marine bacteria". Microbiology Australia 39, n. 1 (2018): 12. http://dx.doi.org/10.1071/ma18005.
Testo completoAbstract (sommario):
Like many organisms, bacteria regularly inhabit environments characterised by spatiotemporal heterogeneity in the availability of resources required for growth and energy generation, meaning they must either tune their metabolism to prevailing conditions or have the capacity to migrate to favourable microenvironments1. To achieve the latter, bacteria measure their resource landscape and suitably direct their locomotion using a behaviour called chemotaxis, which is the ability to guide movement up or down chemical gradients. The capacity to perform chemotaxis is widespread across the bacterial domain, although most of our understanding of this phenotype is derived from enteric bacteria2,3. In the ocean, marine bacteria are often motile4, and in fact capable of much higher swimming speeds5 and chemotactic precision6 than these enteric models for chemotaxis2. Here we discuss the underlying motives and purposes for bacterial chemotaxis in the ocean, by noting that marine bacteria experience a surprisingly heterogeneous chemical seascape7,8, whereby chemotaxis can provide substantial fitness advantages and even influence large-scale processes including marine ecosystem productivity, biogeochemical cycling and disease.
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Marzuki, Ismail, Khairun Nisaa, Ruzkiah Asaf, Admi Athirah, Mudian Paena, Endang Susianingsih, Nurhidayah Nurhidayah et al. "Comparison of Pyrene Biodegradation Using Two Types of Marine Bacterial Isolates". Sustainability 14, n. 16 (10 agosto 2022): 9890. http://dx.doi.org/10.3390/su14169890.
Testo completoAbstract (sommario):
Polycyclic aromatic hydrocarbons (PAHs) contaminants have toxic, carcinogenic, and mutagenic properties. Screening bacteria from different sources capable of carrying out the biodegradation of (PAHs) is essential for mapping and mobilization purposes and applying them to polluted hydrocarbon environments. The study aims to compare the capacity of PAH biodegradation by two types of bacteria isolated from different sources. The method applied is the interaction between bacterial suspension and pyrene-contaminated waste for 30 days. Biodegradation products in organic compounds were analyzed using gas chromatography/mass spectroscopy (GC/MS) and Fourier transform infrared spectroscopy (FTIR). The analysis results found several indications of the performance of bacterial biodegradation: The capacity of pyrene degradation by Bacillus licheniformis strain ATCC 9789 (Bl) bacteria against pyrene was relatively more dominant than Sphingobacterium sp. strain 21 (Sb) bacteria. The percentage of total bacterial biodegradation for product type Sb was (39.00%), and that of the product of bacterial degradation type Bl (38.29%). The biodegradation products of the test bacteria (Bl and Sb) were relatively similar to pyrene in the form of alcohol and carboxylic acid organic compounds. There was no significant difference in the pyrene biodegradation between Bl and Sb bacteria.
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Guillonneau, Richard, Claudine Baraquet e Maëlle Molmeret. "Marine Bacteria Display Different Escape Mechanisms When Facing Their Protozoan Predators". Microorganisms 8, n. 12 (12 dicembre 2020): 1982. http://dx.doi.org/10.3390/microorganisms8121982.
Testo completoAbstract (sommario):
Free-living amoeba are members of microbial communities such as biofilms in terrestrial, fresh, and marine habitats. Although they are known to live in close association with bacteria in many ecosystems such as biofilms, they are considered to be major bacterial predators in many ecosystems. Little is known on the relationship between protozoa and marine bacteria in microbial communities, more precisely on how bacteria are able survive in environmental niches where these bacterial grazers also live. The objective of this work is to study the interaction between the axenized ubiquitous amoeba Acanthamoeba castellanii and four marine bacteria isolated from immersed biofilm, in order to evaluate if they would be all grazed upon by amoeba or if they would be able to survive in the presence of their predator. At a low bacteria-to-amoeba ratio, we show that each bacterium is phagocytized and follows a singular intracellular path within this host cell, which appears to delay or to prevent bacterial digestion. In particular, one of the bacteria was found in the amoeba nucleolar compartment whereas another strain was expelled from the amoeba in vesicles. We then looked at the fate of the bacteria grown in a higher bacteria-to-amoeba ratio, as a preformed mono- or multi-species biofilm in the presence of A. castellanii. We show that all biofilms were subjected to detachment from the surface in the presence of the amoeba or its supernatant. Overall, these results show that bacteria, when facing the same predator, exhibit a variety of escape mechanisms at the cellular and population level, when we could have expected a simple bacterial grazing. Therefore, this study unravels new insights into the survival of environmental bacteria when facing predators that they could encounter in the same microbial communities.
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Tang, Kam W., e Hans-Peter Grossart. "Iron effects on colonization behavior, motility, and enzymatic activity of marine bacteria". Canadian Journal of Microbiology 53, n. 8 (agosto 2007): 968–74. http://dx.doi.org/10.1139/w07-059.
Testo completoAbstract (sommario):
Iron availability in the ocean has been shown to affect the growth and production of phytoplankton and free-living bacteria. A large fraction of marine bacteria are specialized in colonizing and living on particles and aggregates, but the effects of iron limitation on these bacteria are not fully known. We conducted laboratory experiments to study the effects of iron availability on particle colonization behavior, motility, and enzymatic activities of 4 strains of marine bacteria. Iron depletion reduced the bacterial particle colonization rate by 1.7%–43.1%, which could be attributed to reduced swimming speeds in 2 of the 4 strains. Protease activity was not affected by iron availability. However, attached bacteria did show higher protease activities than their free counterparts. Our results suggest that iron limitation in the ocean could in some cases reduce bacteria–particle interactions by reducing bacterial motility and colonization rate.
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Gautam, Pratima, Ivan Erill e Kathleen D. Cusick. "Linking Copper-Associated Signal Transduction Systems with Their Environment in Marine Bacteria". Microorganisms 11, n. 4 (13 aprile 2023): 1012. http://dx.doi.org/10.3390/microorganisms11041012.
Testo completoAbstract (sommario):
Copper is an essential trace element for living cells. However, copper can be potentially toxic for bacterial cells when it is present in excess amounts due to its redox potential. Due to its biocidal properties, copper is prevalent in marine systems due to its use in antifouling paints and as an algaecide. Thus, marine bacteria must possess means of sensing and responding to both high copper levels and those in which it is present at only typical trace metal levels. Bacteria harbor diverse regulatory mechanisms that respond to intracellular and extracellular copper and maintain copper homeostasis in cells. This review presents an overview of the copper-associated signal transduction systems in marine bacteria, including the copper efflux systems, detoxification, and chaperone mechanisms. We performed a comparative genomics study of the copper-regulatory signal transduction system on marine bacteria to examine the influence of the environment on the presence, abundance, and diversity of copper-associated signal transduction systems across representative phyla. Comparative analyses were performed among species isolated from sources, including seawater, sediment, biofilm, and marine pathogens. Overall, we observed many putative homologs of copper-associated signal transduction systems from various copper systems across marine bacteria. While the distribution of the regulatory components is mainly influenced by phylogeny, our analyses identified several intriguing trends: (1) Bacteria isolated from sediment and biofilm displayed an increased number of homolog hits to copper-associated signal transduction systems than those from seawater. (2) A large variability exists for hits to the putative alternate σ factor CorE hits across marine bacteria. (3) Species isolated from seawater and marine pathogens harbored fewer CorE homologs than those isolated from the sediment and biofilm.
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Bone, Pratiwi, Desy MH Mantiri, Kurniati Kemer, Robert Bara, Rizald Max Rompas e Reiny Tumbol. "BAKTERI RESISTEN ARSEN (As) PADA ALGA Padina australis DARI PERAIRAN KIMA BAJO". JURNAL PESISIR DAN LAUT TROPIS 9, n. 3 (4 ottobre 2021): 14. http://dx.doi.org/10.35800/jplt.9.3.2021.36090.
Testo completoAbstract (sommario):
Padina australis is a species of marine algae from the Phaeophyta division (brown algae) which is generally distributed in marine waters. This algae is able to live in waters with high levels of heavy metals such as in the Kima Bajo waters. This study aims to isolate arsenic (As)-resistant bacteria in P. australis, observe cell shape and bacterial characteristics, and determine bacterial resistance to antibiotics. The method used is conventional bacterial isolation which has been tested on As2O3 compounds. The results obtained were that P. australis contained arsenic resistant bacteria at concentrations of 250 ppm, 500 ppm, and 1000 ppm. The bacteria obtained were Gram positive, in the form of bacilli. These arsenic-resistant bacteria are also resistant to antibiotics such as amoxicillin, cefixime, and doxycycline.Keywords: Padina australis, Arsen (As), Kima Bajo
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Dr. Abdul Nabi. "SCREENING OF MARINE BACTERIUM VIBRIO ALGINOLYTICUS STRAIN AS05 FOR THE PRODUCTION OF N-ACYL HOMOSERINE LACTONE-BASED QUORUM SENSING SIGNALING MOLECULES". Pakistan Journal of Science 74, n. 1-1 (27 marzo 2023): 7–11. http://dx.doi.org/10.57041/pjs.v74i1-1.791.
Testo completoAbstract (sommario):
Marine environments, including aquatic and coastal environments, are highly prevalent of marine bacteria with the highest levels of Vibrio species. Vibrios play a vital role in marine ecology associated with carbon and energy acquisition. The density-dependent quorum sensing (QS) system may regulate certain biological activities in marine bacteria. QS is a conversation system utilized by many bacterial communities to communicate and coordinate through different signalling molecules. N-acyl homoserine lactones (AHLs) are the most important QS signalling molecules widely produced by Gram-negative bacteria. This study aimed to investigate the detection and Identification of AHL-based QS signalling molecules produced by marine bacterium V. alginolyticus strain AS05 isolated from marine water of the Arabian Sea, Karachi, Pakistan. Marine medium Zobell-2216 was used to isolate bacterial strains. Moreover, 16S rRNA analysis was applied to identify AS05 strain. Agar plate bioassay was used to detect the production of AHL signalling molecules using Chromobacterium violaceum CV026 as a biosensor. The Identification of AHLs was made by reversed-phase thin-layer chromatography (RP-TLC) analysis. The NCBI-blast results revealed the identification of the isolated bacterial strain as Vibrio alginolyticus strain AS05 (OQ130030) member of the family of Vibrionaceae under the class of Gammaproteobacteria. The results of agar plate bioassay using CV026 as a biosensor strain revealed highly positive reactions for producing AHL signalling molecules. Moreover, two AHL molecules produced by AS05 bacterial strain were identified as C6-HSL and C-8HSL based on TLC analysis. This study reveals the detection and Identification of two different AHL signalling molecules produced by V. alginolyticus AS05 isolated from marine water of the Arabian Sea, Karachi, Pakistan. This study provides insight into investigating quorum-sensing signalling molecules in the Arabian Sea, Karachi, Pakistan, and marine bacterial species.
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Bibi, Fehmida. "Exploring bioactive compounds from a symbiotic bacterial strain of Spongiobacter sp." Bioinformation 19, n. 4 (30 aprile 2023): 369–74. http://dx.doi.org/10.6026/97320630019369.
Testo completoAbstract (sommario):
Marine sponges are a host of different symbiotic groups of bacteria playing crucial roles in the protection and survival of marine sponges. Marine symbiotic bacteria from sponges are promising sources of bioactive chemicals and are increasingly being investigated. Therefore, the present study was undertaken to analyze total compounds from active symbiotic bacterial strain from sponge, Pione vastifica. Potential bacterial strain EA276 previously isolated from P. vastifica and was identified as Spongiobacter sp. Among 57 isolates, only 42% exhibited antagonistic activity. Four major classes of bacteria were reported previously where γ-Proteobacteria, was the dominant class. From these active antagonistic bacterial isolates, a potential bacterial strain Spongiobacter sp. EA276 was selected, and total metabolites were identified using GC and LC-MS analyses. Using LC-MS analysis bioactive compounds Dichlorphenamide, Amifloxacin and Carbenicillin are identified in both positive and negative mode. Plant growth hormones, Indole-3-acetic acid and Methyl jasmonate were identified using GC-MS analysis from culture extract of strain Spongiobacter sp. EA276. Our results highlighted the significance of marine flora inhabiting sponges from the Red Sea as potential source of bioactive compounds and plant growth hormones of biological and agricultural significance.
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Cheng, T. H., N. Ismail, N. Kamaruding, J. Saidin e M. Danish-Daniel. "Industrial enzymes-producing marine bacteria from marine resources". Biotechnology Reports 27 (settembre 2020): e00482. http://dx.doi.org/10.1016/j.btre.2020.e00482.
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Luna, G. M., E. Manini e R. Danovaro. "Large Fraction of Dead and Inactive Bacteria in Coastal Marine Sediments: Comparison of Protocols for Determination and Ecological Significance". Applied and Environmental Microbiology 68, n. 7 (luglio 2002): 3509–13. http://dx.doi.org/10.1128/aem.68.7.3509-3513.2002.
Testo completoAbstract (sommario):
ABSTRACT It is now universally recognized that only a portion of aquatic bacteria is actively growing, but quantitative information on the fraction of living versus dormant or dead bacteria in marine sediments is completely lacking. We compared different protocols for the determination of the dead, dormant, and active bacterial fractions in two different marine sediments and at different depths into the sediment core. Bacterial counts ranged between (1.5 ± 0.2) × 108 cells g−1 and (53.1 ± 16.0) × 108 cells g−1 in sandy and muddy sediments, respectively. Bacteria displaying intact membrane (live bacterial cells) accounted for 26 to 30% of total bacterial counts, while dead cells represented the most abundant fraction (70 to 74%). Among living bacterial cells, nucleoid-containing cells represented only 4% of total bacterial counts, indicating that only a very limited fraction of bacterial assemblage was actively growing. Nucleoid-containing cells increased with increasing sediment organic content. The number of bacteria responsive to antibiotic treatment (direct viable count; range, 0.3 to 4.8% of the total bacterial number) was significantly lower than nucleoid-containing cell counts. An experiment of nutrient enrichment to stimulate a response of the dormant bacterial fraction determined a significant increase of nucleoid-containing cells. After nutrient enrichment, a large fraction of dormant bacteria (6 to 11% of the total bacterial number) was “reactivated.” Bacterial turnover rates estimated ranged from 0.01 to 0.1 day−1 but were 50 to 80 times higher when only the fraction of active bacteria was considered (on average 3.2 day−1). Our results suggest that the fraction of active bacteria in marine sediments is controlled by nutrient supply and availability and that their turnover rates are at least 1 order of magnitude higher than previously reported.
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P, Rashmi. "Exploring Uncharted Marine Bacteria as a Source of Novel Antimicrobials". International Journal of Oceanography & Aquaculture 7, n. 4 (2023): 1–4. http://dx.doi.org/10.23880/ijoac-16000276.
Testo completoAbstract (sommario):
Marine microbes are defined by their habitat as microorganisms living in the sea or ocean. The term “marine microbes” includes viruses, protozoa and fungi. This microbial life constitutes 70% To 90% of marine biomass. More than 15000 bioactive compounds have been isolated from marine fungi, and other organisms and used as anti-inflammatory, and anticancer leads. Among the microorganisms of marine, bacteria are the least explored ones. Marine actinobacteria have adapted to high hydrostatic pressure, high concentration of Sodium Chloride, low concentration of organic matter, and low temperature. The phylum actinobacteria is a Gram-positive, nonmotile, and aerobic bacteria. Streptomyces and Actinomycetes are studied largely in this phylum due to their ability to produce a wide array of extracellular enzymes and secondary metabolites. Examples of active compounds isolated from Streptomyces include Fijimycins, etamycin A, Chlorinated bisindole pyrroles, and dynamics A–E. There may be diverse extremo enzymes hidden in the shadows that are currently unknown and, if discovered, may open up interesting new methods for the production and use of novel antimicrobials. In pharmaceutical research, a very small fraction of such organisms is studied. If discovered may open up interesting new ingenious, and cost-effective methods for the production and use of many novel anti-microbials.
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Wondal, Bella, Elvy Like Ginting, Veibe Warouw, Stenly Wullur, Sandra Olivia Tilaar e Ferdinand Frans Tilaar. "ISOLASI BAKTERI LAUT DARI PERAIRAN MALALAYANG, SULAWESI UTARA". JURNAL PESISIR DAN LAUT TROPIS 7, n. 3 (23 luglio 2019): 183. http://dx.doi.org/10.35800/jplt.7.3.2019.24448.
Testo completoAbstract (sommario):
Marine bacteria have a lot of potential in exploring the enzyme that can be developed, such as a producer of proteorhodopsin, act as hydrocarbon chlorlastic and can degrade oil. This study aims to obtain isolates and can characterize the bacterial morphology. Malalayang Waters is one of the marine bacterial habitats that has potential area to be studied. This study aims to isolate marine bacteria from Malalayang Waters. These marine bacteria first were diluted into sea water before they were grown on Nutrient Agar (NA). Based on the results of this study it was found that marine bacterial isolated were separated based on their morphological characteristics. The dominant morphological characteristics were yellow whites which dominant shape were irregular.Keywords: bacterial, dilution, isolation. Bakteri laut memiliki banyak potensi yang dapat dikembangkan. Seperti penghasil proteorhodopsin, berperan sebagai hidrokarbonoklastik dan dapat mendegradasi minyak. Perairan Malalayang merupakan salah satu habitat bakteri laut yang belum diteliti. Penelitian ini bertujuan untuk mengisolasi bakteri laut dari Perairan Malalayang. Bakteri laut ditumbuhkan pada media agar + air laut, selain itu bakteri juga dilakukan pengenceran terhadap air laut sebelum bakteri ditumbuhkan pada media Nutrient Agar (NA). Berdasarkan hasil penelitian ini isolat bakteri laut ditemukan, bakteri tersebut dipisahkan berdasarkan karakteristik morfologinya. Karakteristik morfologi yang dimiliki dominan berwarna putih kuning dan memiliki bentuk yang dominan tidak teratur. Hal ini dapat memperlihatkan perbedaan bakteri laut dari Perairan Malalayang yang tumbuh.Kata kunci: bakteri, pengenceran, isolasi.
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Maldonado-Ruiz, Karina, Ruth Pedroza-Islas e Lorena Pedraza-Segura. "Blue Biotechnology: Marine Bacteria Bioproducts". Microorganisms 12, n. 4 (29 marzo 2024): 697. http://dx.doi.org/10.3390/microorganisms12040697.
Testo completoAbstract (sommario):
The ocean is the habitat of a great number of organisms with different characteristics. Compared to terrestrial microorganisms, marine microorganisms also represent a vast and largely unexplored reservoir of bioactive compounds with diverse industrial applications like terrestrial microorganisms. This review examines the properties and potential applications of products derived from marine microorganisms, including bacteriocins, enzymes, exopolysaccharides, and pigments, juxtaposing them in some cases against their terrestrial counterparts. We discuss the distinct characteristics that set marine-derived products apart, including enhanced stability and unique structural features such as the amount of uronic acid and sulfate groups in exopolysaccharides. Further, we explore the uses of these marine-derived compounds across various industries, ranging from food and pharmaceuticals to cosmetics and biotechnology. This review also presents a broad description of biotechnologically important compounds produced by bacteria isolated from marine environments, some of them with different qualities compared to their terrestrial counterparts.
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Mahardika, K., I. Mastuti, R. Septory, A. Nasukha e I. N. A. Giri. "Bacterial density variations of the coastal waters from three marine aquaculture centers in Bali, Indonesia". IOP Conference Series: Earth and Environmental Science 1221, n. 1 (1 agosto 2023): 012011. http://dx.doi.org/10.1088/1755-1315/1221/1/012011.
Testo completoAbstract (sommario):
Abstract The highly dynamic nature of marine waters can create unique characteristics for bacterial communities. The purpose of this study was to quantify the number of bacteria present in the beach sand and coastal waters of three marine aquaculture centers in Bali, Indonesia. Two locations that have developed were selected (Patas Village and Candikusuma Village). While an advance centre was located in Sumberkima Village Bay. Sampling was done in March-April 2021. Seawater and beach sand from the three locations were collected and analyzed for total plate count bacteria, Vibrio sp., halotolerant bacteria, rod-shaped gram-negative bacteria and anaerobic facultative bacteria. Sampling of sea water was carried out at 4-5 points around floating net cages and beach sand around the location. The sampling results showed that the total plate count bacteria and halotolerant bacteria in coastal waters from the three locations were less varied. While number of Vibrio sp. in Candikusuma Village lower than the Vibrio sp. in two centre. Rod-shaped gram-negative bacteria were found in advance centre (Sumberkima Village). Sand beach bacteria from Sumberkima Village and Patas Village have similar number of total plate count bacteria, Vibrio sp., halotolerant bacteria and rod-shaped gram-negative bacteria. However, the number of these bacteria were significant different with the same bacterial on the beach sand of Candikusuma Village, except anaerobic facultative bacteria. These results indicate that the bacterial population is influenced by development of aquaculture activities in coastal waters.
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Long, Richard A., David C. Rowley, Eric Zamora, Jiayuan Liu, Douglas H. Bartlett e Farooq Azam. "Antagonistic Interactions among Marine Bacteria Impede the Proliferation of Vibrio cholerae". Applied and Environmental Microbiology 71, n. 12 (dicembre 2005): 8531–36. http://dx.doi.org/10.1128/aem.71.12.8531-8536.2005.
Testo completoAbstract (sommario):
ABSTRACT Changes in global climate have raised concerns about the emergence and resurgence of infectious diseases. Vibrio cholerae is a reemerging pathogen that proliferates and is transported on marine particles. Patterns of cholera outbreaks correlate with sea surface temperature increases, but the underlying mechanisms for rapid proliferation of V. cholerae during ocean warming events have yet to be fully elucidated. In this study, we tested the hypothesis that autochthonous marine bacteria impede the spread of V. cholerae in the marine environment. It was found that some marine bacteria are capable of inhibiting the growth of V. cholerae on surfaces and that bacterial isolates derived from pelagic particles show a greater frequency of V. cholerae inhibition than free-living bacteria. Vibrio cholerae was less susceptible to antagonism at higher temperatures, such as those measured during El Niño-Southern Oscilliation and monsoonal events. Using a model system employing green fluorescent protein-labeled bacteria, we found that marine bacteria can directly inhibit V. cholerae colonization of particles. The mechanism of inhibition in our model system was linked to the biosynthesis of andrimid, an antibacterial agent. Antibiotic production by the model antagonistic strain decreased at higher temperatures, thereby explaining the increased competitiveness of V. cholerae under warmer conditions. These findings suggest that bacterium-bacterium antagonism is a contributing mechanism in regulating the proliferation of V. cholerae on marine particles.
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Kim, Hyewon Heather, Jeff S. Bowman, Ya-Wei Luo, Hugh W. Ducklow, Oscar M. Schofield, Deborah K. Steinberg e Scott C. Doney. "Modeling polar marine ecosystem functions guided by bacterial physiological and taxonomic traits". Biogeosciences 19, n. 1 (6 gennaio 2022): 117–36. http://dx.doi.org/10.5194/bg-19-117-2022.
Testo completoAbstract (sommario):
Abstract. Heterotrophic marine bacteria utilize organic carbon for growth and biomass synthesis. Thus, their physiological variability is key to the balance between the production and consumption of organic matter and ultimately particle export in the ocean. Here we investigate a potential link between bacterial traits and ecosystem functions in the rapidly warming West Antarctic Peninsula (WAP) region based on a bacteria-oriented ecosystem model. Using a data assimilation scheme, we utilize the observations of bacterial groups with different physiological traits to constrain the group-specific bacterial ecosystem functions in the model. We then examine the association of the modeled bacterial and other key ecosystem functions with eight recurrent modes representative of different bacterial taxonomic traits. Both taxonomic and physiological traits reflect the variability in bacterial carbon demand, net primary production, and particle sinking flux. Numerical experiments under perturbed climate conditions demonstrate a potential shift from low nucleic acid bacteria to high nucleic acid bacteria-dominated communities in the coastal WAP. Our study suggests that bacterial diversity via different taxonomic and physiological traits can guide the modeling of the polar marine ecosystem functions under climate change.
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Lennon, Jay T. "Diversity and Metabolism of Marine Bacteria Cultivated on Dissolved DNA". Applied and Environmental Microbiology 73, n. 9 (2 marzo 2007): 2799–805. http://dx.doi.org/10.1128/aem.02674-06.
Testo completoAbstract (sommario):
ABSTRACT Dissolved DNA (dDNA) is a potentially important source of energy and nutrients in aquatic ecosystems. However, little is known about the identity, metabolism, and interactions of the microorganisms capable of consuming dDNA. Bacteria from Eel Pond (Woods Hole, MA) were cultivated on low-molecular-weight (LMW) or high-molecular-weight (HMW) dDNA, which served as the primary source of carbon, nitrogen, and phosphorus. Cloning and sequencing of 16S rRNA genes revealed that distinct bacterial assemblages with comparable levels of taxon richness developed on LMW and HMW dDNA. Since the LMW and HMW dDNA used in this study were stoichiometrically identical, the results confirm that the size alone of dissolved organic matter can influence bacterial community composition. Variation in the growth and metabolism of isolates provided insight into mechanisms that may have generated differences in bacterial community composition. For example, bacteria from LMW dDNA enrichments generally grew better on LMW dDNA than on HMW dDNA. In contrast, bacteria isolated from HMW dDNA enrichments were more effective at degrading HMW dDNA than bacteria isolated from LMW dDNA enrichments. Thus, marine bacteria may experience a trade-off between their ability to compete for LMW dDNA and their ability to access HMW dDNA via extracellular nuclease production. Together, the results of this study suggest that dDNA turnover in marine ecosystems may involve a succession of microbial assemblages with specialized ecological strategies.
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Seo, Y., E. Ikemoto, A. Yoshida e K. Kogure. "Particle capture by marine bacteria". Aquatic Microbial Ecology 49 (29 novembre 2007): 243–53. http://dx.doi.org/10.3354/ame01147.
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Kajiwara, Hitomi, Toshiki Mine e Takeshi Yamamoto. "Sialyltransferases Obtained from Marine Bacteria". Journal of Applied Glycoscience 56, n. 2 (2009): 77–82. http://dx.doi.org/10.5458/jag.56.77.
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Shiba, Tsuneo. "Starvation Survival of Marine Bacteria." Oceanography in Japan 1, n. 4 (1992): 167–75. http://dx.doi.org/10.5928/kaiyou.1.167.
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Simidu, U., T. Noguchi, D. F. Hwang, Y. Shida e K. Hashimoto. "Marine bacteria which produce tetrodotoxin." Applied and Environmental Microbiology 53, n. 7 (1987): 1714–15. http://dx.doi.org/10.1128/aem.53.7.1714-1715.1987.
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Maeda, Rintaro, Hiroshi Nagashima, Jaka Widada, Kenichi Iwata e Toshio Omori. "Novel marine carbazole-degrading bacteria". FEMS Microbiology Letters 292, n. 2 (marzo 2009): 203–9. http://dx.doi.org/10.1111/j.1574-6968.2009.01497.x.
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