Displaying publications 301 - 320 of 942 in total

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  1. Hisham MB, Hashim AM, Mohd Hanafi N, Abdul Rahman N, Abdul Mutalib NE, Tan CK, et al.
    Sci Rep, 2022 May 02;12(1):7107.
    PMID: 35501317 DOI: 10.1038/s41598-022-08819-4
    Silage produced in tropical countries is prone to spoilage because of high humidity and temperature. Therefore, determining indigenous bacteria as potential inoculants is important to improve silage quality. This study aimed to determine bacterial community and functional changes associated with ensiling using amplicon metagenomics and to predict potential bacterial additives associated with silage quality in the Malaysian climate. Silages of two forage crops (sweet corn and Napier) were prepared, and their fermentation properties and functional bacterial communities were analysed. After ensiling, both silages were predominated by lactic acid bacteria (LAB), and they exhibited good silage quality with significant increment in lactic acid, reductions in pH and water-soluble carbohydrates, low level of acetic acid and the absence of propionic and butyric acid. LAB consortia consisting of homolactic and heterolactic species were proposed to be the potential bacterial additives for sweet corn and Napier silage fermentation. Tax4fun functional prediction revealed metabolic pathways related to fermentation activities (bacterial division, carbohydrate transport and catabolism, and secondary metabolite production) were enriched in ensiled crops (p 
    Matched MeSH terms: Bacteria
  2. Mohd-Nor D, Ramli N, Sharuddin SS, Hassan MA, Mustapha NA, Ariffin H, et al.
    Microbes Environ, 2019 Jun 27;34(2):121-128.
    PMID: 30905894 DOI: 10.1264/jsme2.ME18104
    Despite efforts to address the composition of the microbial community during the anaerobic treatment of palm oil mill effluent (POME), its composition in relation to biodegradation in the full-scale treatment system has not yet been extensively examined. Therefore, a thorough analysis of bacterial and archaeal communities was performed in the present study using MiSeq sequencing at the different stages of the POME treatment, which comprised anaerobic as well as facultative anaerobic and aerobic processes, including the mixed raw effluent (MRE), mixing pond, holding tank, and final discharge phases. Based on the results obtained, the following biodegradation processes were suggested to occur at the different treatment stages: (1) Lactobacillaceae (35.9%) dominated the first stage, which contributed to high lactic acid production; (2) the higher population of Clostridiaceae in the mixing pond (47.7%) and Prevotellaceae in the holding tank (49.7%) promoted acetic acid production; (3) the aceticlastic methanogen Methanosaetaceae (0.6-0.8%) played a role in acetic acid degradation in the open digester and closed reactor for methane generation; (4) Syntrophomonas (21.5-29.2%) appeared to be involved in the degradation of fatty acids and acetic acid by syntrophic cooperation with the hydrogenotrophic methanogen, Methanobacteriaceae (0.6-1.3%); and (5) the phenols and alcohols detected in the early phases, but not in the final discharge phase, indicated the successful degradation of lignocellulosic materials. The present results contribute to a better understanding of the biodegradation mechanisms involved in the different stages of the full-scale treatment of POME.
    Matched MeSH terms: Bacteria/classification; Bacteria/isolation & purification; Bacteria/metabolism
  3. Amil MA, Rahman SNSA, Yap LF, Razak FA, Bakri MM, Salem LSO, et al.
    Chem Biodivers, 2024 Mar;21(3):e202301836.
    PMID: 38253795 DOI: 10.1002/cbdv.202301836
    Essential oils have been recognised for their potential benefits in oral care. The aim of this study was to evaluate the antibacterial and antiproliferative activity of essential oils derived from four Zingiberaceae species. A combination of GC/MS and GC-FID was employed to analyse these essential oils. The results showed that β-myrcene (79.77 %) followed by ethyl-cinnamate (40.14 %), β-curcumene (34.90 %), and alloaromadendrene (25.15 %) as the primary constituents of Curcuma mangga, Curcuma xanthorrhiza, Kaempferia galanga and Curcuma aeruginosa, respectively. The Zingiberaceae oils were tested for their antibacterial activity against oral bacteria using the disc diffusion test. Curcuma xanthorrhiza oil showed the largest inhibition zones against Streptococcus mitis (19.50±2.22 mm) and Streptococcus sanguinis (15.04±3.05 mm). Similarly, Curcuma mangga oil exhibited significant antibacterial activity against Streptococcus mutans (12.55±0.45 mm) and mixed oral bacteria (15.03±3.82 mm). Furthermore, the MTT viability assay revealed moderate inhibitory activity of these essential oils against H103 and ORL-204 oral cancer cells. The study findings demonstrate that Curcuma xanthorrhiza and Curcuma mangga essential oils have potent antibacterial properties, suggesting their potential use as natural alternatives to synthetic antibacterial agents in oral care products. However, further investigations are necessary to fully explore their therapeutic applications.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacology; Bacteria
  4. Dhahi TS, Dafhalla AKY, Saad SA, Zayan DMI, Ahmed AET, Elobaid ME, et al.
    Biotechnol Appl Biochem, 2024 Apr;71(2):429-445.
    PMID: 38238920 DOI: 10.1002/bab.2550
    Infectious diseases, caused by pathogenic microorganisms such as bacteria, viruses, parasites, or fungi, are crucial for efficient disease management, reducing morbidity and mortality rates and controlling disease spread. Traditional laboratory-based diagnostic methods face challenges such as high costs, time consumption, and a lack of trained personnel in resource-poor settings. Diagnostic biosensors have gained momentum as a potential solution, offering advantages such as low cost, high sensitivity, ease of use, and portability. Nanobiosensors are a promising tool for detecting and diagnosing infectious diseases such as coronavirus disease, human immunodeficiency virus, and hepatitis. These sensors use nanostructured carbon nanotubes, graphene, and nanoparticles to detect specific biomarkers or pathogens. They operate through mechanisms like the lateral flow test platform, where a sample containing the biomarker or pathogen is applied to a test strip. If present, the sample binds to specific recognition probes on the strip, indicating a positive result. This binding event is visualized through a colored line. This review discusses the importance, benefits, and potential of nanobiosensors in detecting infectious diseases.
    Matched MeSH terms: Bacteria
  5. Sariyati NH, Othman N, Abdullah-Fauzi NAF, Chan E, Md-Zain BM, Karuppannan KV, et al.
    J Med Primatol, 2024 Oct;53(5):e12730.
    PMID: 39148344 DOI: 10.1111/jmp.12730
    BACKGROUND: The gut morphology of Symphalangus syndactylus exhibits an intermediate structure that aligns with its consumption of fruit and ability to supplement its diet with leaves. The Siamang relies on its gut microbiome for energy extraction, immune system development, and the synthesis of micronutrients. Gut microbiome composition may be structured based on several factors such as age, sex, and habitat. No study has yet been carried out on the gut microbiota of the Hylobatidae members in Malaysia especially S. syndactylus.

    METHODS: This study aims to resolve the gut microbiome composition of S. syndactylus by using a fecal sample as DNA source, adapting high-throughput sequencing, and 16S rRNA as the targeted region.

    RESULTS: A total of 1 272 903 operational taxonomic units (OTUs) reads were assigned to 22 phyla, 139 families, and 210 genera of microbes. The {Unknown Phylum} Bacteria-2 is the dominant phyla found across all samples. Meanwhile, {Unknown Phylum} Bacteria-2 and Firmicutes are genera that have the highest relative abundance found in the Siamang gut.

    CONCLUSIONS: This study yields nonsignificance relationship between Siamang gut microbiome composition with these three factors: group, sex, and age.

    Matched MeSH terms: Bacteria/classification; Bacteria/genetics; Bacteria/isolation & purification; RNA, Bacterial/analysis; RNA, Bacterial/genetics
  6. Farah Nadia O, Xiang LY, Lie LY, Chairil Anuar D, Mohd Afandi MP, Azhari Baharuddin S
    J Environ Sci (China), 2015 Feb 1;28:81-94.
    PMID: 25662242 DOI: 10.1016/j.jes.2014.07.023
    Co-composting of poultry manure and rubber wood sawdust was performed with the ratio of 2:1 (V/V) for a period of 60 days. An investigation was carried out to study the extracellular enzymatic activities and structural degradation utilizing Fourier transform infrared spectroscopy (FT-IR), thermogravimetry and differential thermal analysis (TG/DTA) and scanning electron microscopy (SEM). The microbial succession was also determined by using denaturing gel gradient electrophoresis (DGGE). The compost was able to reach its highest temperature of 71°C at day 3 and stabilized between 30 and 40°C for 8 weeks. CMCase, FPase and β-glucosidase acted synergistically in order to degrade the cellulosic substrate. The xylanase activities increased gradually during the composting and reached the peak value of 11.637 U/g on day 35, followed by a sharp decline. Both LiP and MnP activities reached their peak values on day 35 with 0.431 and 0.132 U/g respectively. The FT-IR spectra revealed an increase in aromaticity and a decrease in aliphatic compounds such as carbohydrates as decomposition proceeded. TGA/DTG data exhibited significant changes in weight loss in compost samples, indicating degradation of organic matter. SEM micrographs showed higher amounts of parenchyma exposed on the surface of rubber wood sawdust at day 60, showing significant degradation. DGGE and 16S rDNA analyses showed that Burkholderia sp., Pandoraea sp., and Pseudomonas sp. were present throughout the composting process. Ornithinibacillus sp. and Castellaniella ginsengisoli were only found in the initial stage of the composting, while different strains of Burkholderia sp. also occurred in the later stage of composting.
    Matched MeSH terms: Bacteria/genetics; Bacteria/isolation & purification*; DNA, Bacterial/genetics
  7. Javadi Nobandegani MB, Saud HM, Yun WM
    Biomed Res Int, 2015;2015:201379.
    PMID: 25632387 DOI: 10.1155/2015/201379
    Phosphate solubilizing bacteria (PSB) can convert insoluble form of phosphorous to an available form. Applications of PSB as inoculants increase the phosphorus uptake by plant in the field. In this study, isolation and precise identification of PSB were carried out in Malaysian (Serdang) oil palm field (University Putra Malaysia). Identification and phylogenetic analysis of 8 better isolates were carried out by 16S rRNA gene sequencing in which as a result five isolates belong to the Beta subdivision of Proteobacteria, one isolate was related to the Gama subdivision of Proteobacteria, and two isolates were related to the Firmicutes. Bacterial isolates of 6upmr, 2upmr, 19upmnr, 10upmr, and 24upmr were identified as Alcaligenes faecalis. Also, bacterial isolates of 20upmnr and 17upmnr were identified as Bacillus cereus and Vagococcus carniphilus, respectively, and bacterial isolates of 31upmr were identified as Serratia plymuthica. Molecular identification and characterization of oil palm strains as the specific phosphate solubilizer can reduce the time and cost of producing effective inoculate (biofertilizer) in an oil palm field.
    Matched MeSH terms: Bacteria/genetics*; Bacteria/isolation & purification; Genes, Bacterial*
  8. Hossain MS, Nik Ab Rahman NN, Balakrishnan V, Alkarkhi AF, Ahmad Rajion Z, Ab Kadir MO
    Waste Manag, 2015 Apr;38:462-73.
    PMID: 25636860 DOI: 10.1016/j.wasman.2015.01.003
    Clinical solid waste (CSW) poses a challenge to health care facilities because of the presence of pathogenic microorganisms, leading to concerns in the effective sterilization of the CSW for safe handling and elimination of infectious disease transmission. In the present study, supercritical carbon dioxide (SC-CO2) was applied to inactivate gram-positive Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis, and gram-negative Escherichia coli in CSW. The effects of SC-CO2 sterilization parameters such as pressure, temperature, and time were investigated and optimized by response surface methodology (RSM). Results showed that the data were adequately fitted into the second-order polynomial model. The linear quadratic terms and interaction between pressure and temperature had significant effects on the inactivation of S. aureus, E. coli, E. faecalis, and B. subtilis in CSW. Optimum conditions for the complete inactivation of bacteria within the experimental range of the studied variables were 20 MPa, 60 °C, and 60 min. The SC-CO2-treated bacterial cells, observed under a scanning electron microscope, showed morphological changes, including cell breakage and dislodged cell walls, which could have caused the inactivation. This espouses the inference that SC-CO2 exerts strong inactivating effects on the bacteria present in CSW, and has the potential to be used in CSW management for the safe handling and recycling-reuse of CSW materials.
    Matched MeSH terms: Bacteria/drug effects*; Bacteria/isolation & purification
  9. Zhou X, Qu Y, Kim BH, Choo PY, Liu J, Du Y, et al.
    Bioresour Technol, 2014 Oct;169:265-70.
    PMID: 25062537 DOI: 10.1016/j.biortech.2014.07.012
    The effects of azide on electron transport of exoelectrogens were investigated using air-cathode MFCs. These MFCs enriched with azide at the concentration higher than 0.5mM generated lower current and coulomb efficiency (CE) than the control reactors, but at the concentration lower than 0.2mM MFCs generated higher current and CE. Power density curves showed overshoot at higher azide concentrations, with power and current density decreasing simultaneously. Electrochemical impedance spectroscopy (EIS) showed that azide at high concentration increased the charge transfer resistance. These analyses might reflect that a part of electrons were consumed by the anode microbial population rather than transferred to the anode. Bacterial population analyses showed azide-enriched anodes were dominated by Deltaproteobacteria compared with the controls. Based on these results it is hypothesized that azide can eliminate the growth of aerobic respiratory bacteria, and at the same time is used as an electron acceptor/sink.
    Matched MeSH terms: Bacteria/drug effects; Bacteria/metabolism
  10. Gopinath SC, Tang TH, Chen Y, Citartan M, Lakshmipriya T
    Biosens Bioelectron, 2014 Oct 15;60:332-42.
    PMID: 24836016 DOI: 10.1016/j.bios.2014.04.014
    The ubiquitous nature of bacteria enables them to survive in a wide variety of environments. Hence, the rise of various pathogenic species that are harmful to human health raises the need for the development of accurate sensing systems. Sensing systems are necessary for diagnosis and epidemiological control of pathogenic organism, especially in the food-borne pathogen and sanitary water treatment facility' bacterial populations. Bacterial sensing for the purpose of diagnosis can function in three ways: bacterial morphological visualization, specific detection of bacterial component and whole cell detection. This paper provides an overview of the currently available bacterial detection systems that ranges from microscopic observation to state-of-the-art smartphone-based detection.
    Matched MeSH terms: Bacteria/cytology*; Bacteria/isolation & purification*
  11. Yusof N, Hassan MA, Yee PL, Tabatabaei M, Othman MR, Mori M, et al.
    Waste Manag Res, 2011 Jun;29(6):602-11.
    PMID: 21447612 DOI: 10.1177/0734242X10397581
    Nitrification of mature sanitary landfill leachate with high-strength of N-NH(4) + (1080-2350 mg L(-1)) was performed in a 10 L continuous nitrification activated sludge reactor. The nitrification system was acclimatized with synthetic leachate during feed batch operation to avoid substrate inhibition before being fed with actual mature leachate. Successful nitrification was achieved with an approximately complete ammonium removal (99%) and 96% of N-NH(4) + conversion to N-NO(-) (3) . The maximum volumetric and specific nitrification rates obtained were 2.56 kg N-NH(4) (+) m(-3) day(-1) and 0.23 g N-NH(4) ( +) g(-1) volatile suspended solid (VSS) day(-1), respectively, at hydraulic retention time (HRT) of 12.7 h and solid retention time of 50 days. Incomplete nitrification was encountered when operating at a higher nitrogen loading rate of 3.14 kg N-NH(4) (+) m(-3) day(-1). The substrate overloading and nitrifiers competition with heterotrophs were believed to trigger the incomplete nitrification. Fluorescence in situ hybridization (FISH) results supported the syntrophic association between the ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria. FISH results also revealed the heterotrophs as the dominant and disintegration of some AOB cell aggregates into single cells which further supported the incomplete nitrification phenomenon.
    Matched MeSH terms: Bacteria/classification; Bacteria/isolation & purification*
  12. Wei OY, Xavier R, Marimuthu K
    Eur Rev Med Pharmacol Sci, 2010 Aug;14(8):675-81.
    PMID: 20707287
    The objective of this study is to gain a better understanding of the antimicrobial properties of the mucus extract of snakehead fish, Channa striatus against selected human and fish pathogenic microbes.
    Matched MeSH terms: Anti-Bacterial Agents/isolation & purification; Anti-Bacterial Agents/pharmacology*; Bacteria/drug effects*; Bacteria/pathogenicity
  13. Ibrahim Z, Amin MF, Yahya A, Aris A, Umor NA, Muda K, et al.
    Water Sci Technol, 2009;60(3):683-8.
    PMID: 19657163 DOI: 10.2166/wst.2009.440
    Microbial flocs formed from raw textile wastewater in a prototype Aerobic Biofilm Reactor (ABR) system were characterised and studied for their potential use in the treatment of textile wastewater. After 90-100 days of operation, microbial flocs of loose irregular structures were obtained from the reactor with good settling velocity of 33 m/h and sludge volume index (SVI) of 48.2 mL/g. Molecular analysis of the flocs using PCR-amplified 16S rDNA sequence showed 98% homology to those of Bacillus sp, Paenibacillus sp and Acromobacter sp. Detection of Ca(2+)(131 mg/g) and Fe(2+)(131 mg/g) using atomic absorption spectrometer might be implicated with the flocs formation. In addition, presence of Co(2+) and Ni(2+) were indicative of the flocs ability to accumulate at least a fraction of the metals' present in the wastewater. When the flocs were used for the treatment of raw textile wastewater, they showed good removal of COD and colour about 55% and 70% respectively, indicating their potential application.
    Matched MeSH terms: Bacteria/isolation & purification; Bacteria/metabolism*
  14. Karunakaran R, Raja NS, Ng KP, Navaratnam P
    J Microbiol Immunol Infect, 2007 Oct;40(5):432-7.
    PMID: 17932604
    Bloodstream infections are an important cause of morbidity and mortality among hospitalized patients and the surveillance of etiological agents in these infections is important for their prevention and treatment. Data on common organisms isolated from blood cultures from Malaysia are limited, and our aim was to identify the common bloodstream isolates in hospitalized patients at the University of Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia.
    Matched MeSH terms: Bacteria/classification; Bacteria/isolation & purification; Bacterial Infections/microbiology*
  15. Dahaban NM, Romli MF, Roslan NR, Kong SS, Cheah FC
    Breastfeed Med, 2013 Aug;8(4):422-3.
    PMID: 23398139 DOI: 10.1089/bfm.2012.0109
    Matched MeSH terms: Bacteria/isolation & purification*; Bacteria/pathogenicity
  16. Tan CK, Natrah I, Suyub IB, Edward MJ, Kaman N, Samsudin AA
    Microbiologyopen, 2019 05;8(5):e00734.
    PMID: 30353678 DOI: 10.1002/mbo3.734
    AIMS: The aim of this study was to identify and compare the gut microbial community of wild and captive Tor tambroides through 16S rDNA metagenetic sequencing followed by functions prediction.

    METHODS AND RESULTS: The library of 16S rDNA V3-V4 hypervariable regions of gut microbiota was amplified and sequenced using Illumina MiSeq. The sequencing data were analyzed using Quantitative Insights into Microbial Ecology (QIIME) pipeline and Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt). The most abundant bacterial phyla in both wild and captive T. tambroides were Firmicutes, Proteobacteria, Fusobacteria and Bacteroidetes. Cetobacterium spp., Peptostreptococcaceae family, Bacteroides spp., Phosphate solubilizing bacteria PSB-M-3, and Vibrio spp. were five most abundant OTU in wild T. tambroides as compared to Cetobacterium spp., Citrobacter spp., Aeromonadaceae family, Peptostreptococcaceae family and Turicibacter spp. in captive T. tambroides.

    CONCLUSION: In this study, the specimens of the wild T. tambroides contain more diverse gut microbiota than of the captive ones. The results suggested that Cetobacterium spp. is one of the core microbiota in guts of T. tambroides. Besides, high abundant Bacteroides spp., Citrobacter spp., Turicibacter spp., and Bacillus spp. may provide important functions in T. tambroides guts.

    SIGNIFICANCE AND IMPACT OF THE STUDY: The results of this study provide significant information of T. tambroides gut microbiota for further understanding of their physiological functions including growth and disease resistance.

    Matched MeSH terms: Bacteria/classification*; Bacteria/genetics*
  17. Ong SY, Zainab-L I, Pyary S, Sudesh K
    Appl Microbiol Biotechnol, 2018 Mar;102(5):2117-2127.
    PMID: 29404644 DOI: 10.1007/s00253-018-8788-9
    Polyhydroxyalkanoate (PHA) is a family of microbial polyesters that is completely biodegradable and possesses the mechanical and thermal properties of some commonly used petrochemical-based plastics. Therefore, PHA is attractive as a biodegradable thermoplastic. It has always been a challenge to commercialize PHA due to the high cost involved in the biosynthesis of PHA via bacterial fermentation and the subsequent purification of the synthesized PHA from bacterial cells. Innovative enterprise by researchers from various disciplines over several decades successfully reduced the cost of PHA production through the efficient use of cheap and renewable feedstock, precisely controlled fermentation process, and customized bacterial strains. Despite the fact that PHA yields have been improved tremendously, the recovery and purification processes of PHA from bacterial cells remain exhaustive and require large amounts of water and high energy input besides some chemicals. In addition, the residual cell biomass ends up as waste that needs to be treated. We have found that some animals can readily feed on the dried bacterial cells that contain PHA granules. The digestive system of the animals is able to assimilate the bacterial cells but not the PHA granules which are excreted in the form of fecal pellets, thus resulting in partial recovery and purification of PHA. In this mini-review, we will discuss this new concept of biological recovery, the selection of the animal model for biological recovery, and the properties and possible applications of the biologically recovered PHA.
    Matched MeSH terms: Bacteria/genetics; Bacteria/metabolism*
  18. Akbar N, Siddiqui R, Sagathevan KA, Khan NA
    Appl Microbiol Biotechnol, 2019 May;103(10):3955-3964.
    PMID: 30941460 DOI: 10.1007/s00253-019-09783-2
    The morbidity and mortality associated with bacterial infections have remained significant despite chemotherapeutic advances. With the emergence of drug-resistant bacterial strains, the situation has become a serious threat to the public health. Thus, there is an urgent need to identify novel antibacterials. The majority of antibiotics available in the market are produced by bacteria isolated from soil. However, the low-hanging fruit has been picked; hence, there is a need to mine bacteria from unusual sources. With this in mind, it is important to note that animals and pests such as cockroaches, snake, crocodiles, and water monitor lizard come across pathogenic bacteria regularly, yet flourish in contaminated environments. These species must have developed methods to defend themselves to counter pathogens. Although the immune system is known to possess antiinfective properties, gut bacteria of animals/pests may also offer a potential source of novel antibacterial agents, and it is the subject of this study. This paper discusses our current knowledge of bacteria isolated from land and marine animals with antibacterial properties and to propose untapped sources for the isolation of bacteria to mine potentially novel antibiotic molecules.
    Matched MeSH terms: Anti-Bacterial Agents/isolation & purification*; Anti-Bacterial Agents/metabolism*; Bacteria/isolation & purification*; Bacteria/metabolism*
  19. Vasudevan U, Gantayat RR, Chidambaram S, Prasanna MV, Venkatramanan S, Devaraj N, et al.
    Environ Geochem Health, 2021 Feb;43(2):1069-1088.
    PMID: 32940833 DOI: 10.1007/s10653-020-00712-1
    Microbes in groundwater play a key role in determining the drinking water quality of the water. The study aims to interpret the sources of microbes in groundwater and its relationship to geochemistry. The study was carried out by collecting groundwater samples and analyzed to obtain various cations and anions, where HCO3-, Cl- and NO3- found to be higher than permissible limits in few samples. Microbial analysis, like total coliform (TC), total viable counts (TVC), fecal coliforms (FC), Vibrio cholera (V. cholerae) and total Streptococci (T. streptococci) were analyzed, and the observations reveal that most of the samples were found to be above the permissible limits adopted by EU, BIS, WHO and USEPA standards. Correlation analysis shows good correlation between Mg2+-HCO3-, K+-NO3-, TVC- V. cholerae and T. streptococci-FC. Major ions like Mg+, K+, NO3, Ca2+ and PO4 along with TS and FC were identified to control the geochemical and microbial activities in the region. The magnesium hardness in the groundwater is inferred to influence the TVC and V. cholerae. The mixing of effluents from different sources reflected the association of Cl with TC. Population of microbes T. streptococci and FC was mainly associated with Ca and Cl content in groundwater, depicting the role of electron acceptors and donors. The sources of the microbial population were observed with respect to the land use pattern and the spatial distribution of hydrogeochemical factors in the region. The study inferred that highest microbial activity in the observed in the residential areas, cultivated regions and around the landfill sites due to the leaching of sewage water and fertilizers runoff into groundwater. The concentrations of ions and microbes were found to be above the permissible limits of drinking water quality standards. This may lead to the deterioration in the health of particular coastal region.
    Matched MeSH terms: Bacteria/classification; Bacteria/growth & development
  20. Tripathi BM, Lee-Cruz L, Kim M, Singh D, Go R, Shukor NA, et al.
    Microb Ecol, 2014 Aug;68(2):247-58.
    PMID: 24658414
    Spatial scaling to some extent determines biodiversity patterns in larger organisms, but its role in microbial diversity patterns is much less understood. Some studies have shown that bacterial community similarity decreases with distance, whereas others do not support this. Here, we studied soil bacterial communities of tropical rainforest in Malaysia at two spatial scales: a local scale with samples spaced every 5 mover a 150-m transect, and a regional scale with samples 1 to 1,800 km apart. PCR-amplified soil DNA for the bacterial 16S rRNA gene targeting the V1–V3 region was pyrosequenced using Roche/454 GS FLX Titanium platform. A ranked partial Mantel test showed a weak correlation between spatial distance and whole bacterial community dissimilarity, but only at the local scale. In contrast, environmental distance was highly correlated with community dissimilarity at both spatial scales,stressing the greater role of environmental variables rather than spatial distance in determining bacterial community variation at different spatial scales. Soil pH was the only environmental parameter that significantly explained the variance in bacterial community at the local scale, whereas total nitrogen and elevation were additional important factors at the regional scale.We obtained similar results at both scales when only the most abundant OTUs were analyzed. A variance partitioning analysis showed that environmental variables contributed more to bacterial community variation than spatial distance at both scales. In total, our results support a strong influence of the environment in determining bacterial community composition in the rainforests of Malaysia. However, it is possible that the remaining spatial distance effect is due to some of the myriad of other environmental factors which were not considered here, rather than dispersal limitation.
    Matched MeSH terms: Bacteria/classification; Bacteria/growth & development*; DNA, Bacterial/genetics
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