Displaying publications 61 - 80 of 107 in total

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  1. Fulltext Mesophilic versus thermophilic anaerobic digestion of cattle manure: methane productivity and microbial ecology
    Moset V, Poulsen M, Wahid R, Højberg O, Møller HB
    Microb Biotechnol, 2015 Sep;8(5):787-800.
    PMID: 25737010 DOI: 10.1111/1751-7915.12271
    In this study, productivity and physicochemical and microbiological (454 sequencing) parameters, as well as environmental criteria, were investigated in anaerobic reactors to contribute to the ongoing debate about the optimal temperature range for treating animal manure, and expand the general knowledge on the relation between microbiological and physicochemical process indicators. For this purpose, two reactor sizes were used (10 m(3) and 16 l), in which two temperature conditions (35°C and 50°C) were tested. In addition, the effect of the hydraulic retention time was evaluated (16 versus 20 days). Thermophilic anaerobic digestion showed higher organic matter degradation (especially fiber), higher pH and higher methane (CH₄) yield, as well as better percentage of ultimate CH₄ yield retrieved and lower residual CH₄ emission, when compared with mesophilic conditions. In addition, lower microbial diversity was found in the thermophilic reactors, especially for Bacteria, where a clear intensification towards Clostridia class members was evident. Independent of temperature, some similarities were found in digestates when comparing with animal manure, including low volatile fatty acids concentrations and a high fraction of Euryarchaeota in the total microbial community, in which members of Methanosarcinales dominated for both temperature conditions; these indicators could be considered a sign of process stability.
    Matched MeSH terms: Bacteria/classification*
  2. Molecular characterization of anaerobic sulfur-oxidizing microbial communities in up-flow anaerobic sludge blanket reactor treating municipal sewage
    Aida AA, Hatamoto M, Yamamoto M, Ono S, Nakamura A, Takahashi M, et al.
    J Biosci Bioeng, 2014 Nov;118(5):540-5.
    PMID: 24930844 DOI: 10.1016/j.jbiosc.2014.04.011
    A novel wastewater treatment system consisting of an up-flow anaerobic sludge blanket (UASB) reactor and a down-flow hanging sponge (DHS) reactor with sulfur-redox reaction was developed for treatment of municipal sewage under low-temperature conditions. In the UASB reactor, a novel phenomenon of anaerobic sulfur oxidation occurred in the absence of oxygen, nitrite and nitrate as electron acceptors. The microorganisms involved in anaerobic sulfur oxidation have not been elucidated. Therefore, in this study, we studied the microbial communities existing in the UASB reactor that probably enhanced anaerobic sulfur oxidation. Sludge samples collected from the UASB reactor before and after sulfur oxidation were used for cloning and terminal restriction fragment length polymorphism (T-RFLP) analysis of the 16S rRNA genes of the bacterial and archaeal domains. The microbial community structures of bacteria and archaea indicated that the genus Smithella and uncultured bacteria within the phylum Caldiserica were the dominant bacteria groups. Methanosaeta spp. was the dominant group of the domain archaea. The T-RFLP analysis, which was consistent with the cloning results, also yielded characteristic fingerprints for bacterial communities, whereas the archaeal community structure yielded stable microbial community. From these results, it can be presumed that these major bacteria groups, genus Smithella and uncultured bacteria within the phylum Caldiserica, probably play an important role in sulfur oxidation in UASB reactors.
    Matched MeSH terms: Bacteria/classification
  3. Fulltext The bacterial aetiology of adult community-acquired pneumonia in Asia: a systematic review
    Peto L, Nadjm B, Horby P, Ngan TT, van Doorn R, Van Kinh N, et al.
    Trans R Soc Trop Med Hyg, 2014 Jun;108(6):326-37.
    PMID: 24781376 DOI: 10.1093/trstmh/tru058
    Community-acquired pneumonia (CAP) is a major cause of adult mortality in Asia. Appropriate empirical treatment depends on knowledge of the pathogens commonly responsible. However, assessing the aetiological significance of identified organisms is often difficult, particularly with sputum isolates that might represent contamination with oropharyngeal flora.
    Matched MeSH terms: Bacteria/classification
  4. Comparison of antimicrobial resistance in neonatal and adult intensive care units in a tertiary teaching hospital
    Ariffin N, Hasan H, Ramli N, Ibrahim NR, Taib F, Rahman AA, et al.
    Am J Infect Control, 2012 Aug;40(6):572-5.
    PMID: 22854380 DOI: 10.1016/j.ajic.2012.02.032
    Intrahospital variations in antimicrobial profiles may be related to many factors. This study compared causative agents of nosocomial bloodstream infections between a neonatal intensive care unit (NICU) that adopted a ward-tailored antibiotic policy and adult intensive care units (ICUs). Data on organisms from blood cultures obtained from the respective wards between 2005 and 2009 were analyzed. Compared with the adult ICUs, the NICU had a higher frequency of Enterobacteriacae and lower frequencies of typical hospital-acquired pathogens (eg, Klebsiella pneumoniae, 17.4% vs 10.0% [P < .001]; Acinetobacter baumannii, 3.9% vs 11.6% [P < .001]). Antibiotic resistance of gram-negative organisms was also significantly lower in the NICU, including resistance to imipenem (5.7% vs 32.1%; P < .001), amikacin (8.8% vs 30.3%), and ceftriaxone (36.1% vs 74.6%; P < .001). This could possibly be due to the ward-tailored antibiotic policy adopted by the NICU but not by the other ICUs.
    Matched MeSH terms: Bacteria/classification
  5. Fulltext In-vitro diagnosis of single and poly microbial species targeted for diabetic foot infection using e-nose technology
    Yusuf N, Zakaria A, Omar MI, Shakaff AY, Masnan MJ, Kamarudin LM, et al.
    BMC Bioinformatics, 2015;16:158.
    PMID: 25971258 DOI: 10.1186/s12859-015-0601-5
    Effective management of patients with diabetic foot infection is a crucial concern. A delay in prescribing appropriate antimicrobial agent can lead to amputation or life threatening complications. Thus, this electronic nose (e-nose) technique will provide a diagnostic tool that will allow for rapid and accurate identification of a pathogen.
    Matched MeSH terms: Bacteria/classification*
  6. Fulltext Microbial diversity of thermophiles with biomass deconstruction potential in a foliage-rich hot spring
    Lee LS, Goh KM, Chan CS, Annie Tan GY, Yin WF, Chong CS, et al.
    Microbiologyopen, 2018 12;7(6):e00615.
    PMID: 29602271 DOI: 10.1002/mbo3.615
    The ability of thermophilic microorganisms and their enzymes to decompose biomass have attracted attention due to their quick reaction time, thermostability, and decreased risk of contamination. Exploitation of efficient thermostable glycoside hydrolases (GHs) could accelerate the industrialization of biofuels and biochemicals. However, the full spectrum of thermophiles and their enzymes that are important for biomass degradation at high temperatures have not yet been thoroughly studied. We examined a Malaysian Y-shaped Sungai Klah hot spring located within a wooded area. The fallen foliage that formed a thick layer of biomass bed under the heated water of the Y-shaped Sungai Klah hot spring was an ideal environment for the discovery and analysis of microbial biomass decay communities. We sequenced the hypervariable regions of bacterial and archaeal 16S rRNA genes using total community DNA extracted from the hot spring. Data suggested that 25 phyla, 58 classes, 110 orders, 171 families, and 328 genera inhabited this hot spring. Among the detected genera, members of Acidimicrobium, Aeropyrum, Caldilinea, Caldisphaera, Chloracidobacterium, Chloroflexus, Desulfurobacterium, Fervidobacterium, Geobacillus, Meiothermus, Melioribacter, Methanothermococcus, Methanotorris, Roseiflexus, Thermoanaerobacter, Thermoanaerobacterium, Thermoanaerobaculum, and Thermosipho were the main thermophiles containing various GHs that play an important role in cellulose and hemicellulose breakdown. Collectively, the results suggest that the microbial community in this hot spring represents a good source for isolating efficient biomass degrading thermophiles and thermozymes.
    Matched MeSH terms: Bacteria/classification
  7. Fulltext Host-specific microbial communities in three sympatric North Sea sponges
    Naim MA, Morillo JA, Sørensen SJ, Waleed AA, Smidt H, Sipkema D
    FEMS Microbiol Ecol, 2014 Nov;90(2):390-403.
    PMID: 25088929 DOI: 10.1111/1574-6941.12400
    The establishment of next-generation technology sequencing has deepened our knowledge of marine sponge-associated microbiota with the identification of at least 32 phyla of Bacteria and Archaea from a large number of sponge species. In this study, we assessed the diversity of the microbial communities hosted by three sympatric sponges living in a semi-enclosed North Sea environment using pyrosequencing of bacterial and archaeal 16S ribosomal RNA gene fragments. The three sponges harbor species-specific communities each dominated by a different class of Proteobacteria. An α-proteobacterial Rhodobacter-like phylotype was confirmed as the predominant symbiont of Halichondria panicea. The microbial communities of Haliclona xena and H. oculata are described for the first time in this study and are dominated by Gammaproteobacteria and Betaproteobacteria, respectively. Several common phylotypes belonging to Chlamydiae, TM6, Actinobacteria, and Betaproteobacteria were detected in all sponge samples. A number of phylotypes of the phylum Chlamydiae were present at an unprecedentedly high relative abundance of up to 14.4 ± 1.4% of the total reads, which suggests an important ecological role in North Sea sponges. These Chlamydiae-affiliated operational taxonomic units may represent novel lineages at least at the genus level as they are only 86-92% similar to known sequences.
    Matched MeSH terms: Bacteria/classification
  8. Fulltext The effects of daily fasting hours on shaping gut microbiota in mice
    Li L, Su Y, Li F, Wang Y, Ma Z, Li Z, et al.
    BMC Microbiol, 2020 03 24;20(1):65.
    PMID: 32209070 DOI: 10.1186/s12866-020-01754-2
    BACKGROUND: It has recently been reported that intermittent fasting shapes the gut microbiota to benefit health, but this effect may be influenced to the exact fasting protocols. The purpose of this study was to assess the effects of different daily fasting hours on shaping the gut microbiota in mice. Healthy C57BL/6 J male mice were subjected to 12, 16 or 20 h fasting per day for 1 month, and then fed ad libitum for an extended month. Gut microbiota was analyzed by 16S rRNA gene-based sequencing and food intake was recorded as well.

    RESULTS: We found that cumulative food intake was not changed in the group with 12 h daily fasting, but significantly decreased in the 16 and 20 h fasting groups. The composition of gut microbiota was altered by all these types of intermittent fasting. At genus level, 16 h fasting led to increased level of Akkermansia and decreased level of Alistipes, but these effects disappeared after the cessation of fasting. No taxonomic differences were identified in the other two groups.

    CONCLUSIONS: These data indicated that intermittent fasting shapes gut microbiota in healthy mice, and the length of daily fasting interval may influence the outcome of intermittent fasting.

    Matched MeSH terms: Bacteria/classification*
  9. Diversity and Coding Potential of the Microbiota in the Photic and Aphotic Zones of Tropical Man-Made Lake with Intensive Aquaculture Activities: a Case Study on Temengor Lake, Malaysia
    Lau NS, Zarkasi KZ, Md Sah ASR, Shu-Chien AC
    Microb Ecol, 2019 Jul;78(1):20-32.
    PMID: 30397794 DOI: 10.1007/s00248-018-1283-0
    Although freshwater biomes cover less than 1% of the Earth's surface, they have disproportionate ecological significances. Attempts to study the taxonomy and function of freshwater microbiota are currently limited to samples collected from temperate lakes. In this study, we investigated samples from the photic and aphotic of an aquaculture site (disturbed) of Temengor Lake, a tropical lake in comparison with the undisturbed site of the lake using 16S rRNA amplicon and shotgun metagenomic approaches. Vertical changes in bacterial community composition and function of the Temengor Lake metagenomes were observed. The photic water layer of Temengor Lake was dominated by typical freshwater assemblages consisting of Proteobacteria, Actinobacteria, Bacteroidetes, Verrucomicrobia, and Cyanobacteria lineages. On the other hand, the aphotic water featured in addition to Proteobacteria, Bacteroidetes, Verrucomicrobia, and two more abundant bacterial phyla that are typically ubiquitous in anoxic habitats (Chloroflexi and Firmicutes). The aphotic zone of Temengor Lake exhibited genetic potential for nitrogen and sulfur metabolisms for which terminal electron acceptors other than oxygen are used in the reactions. The aphotic water of the disturbed site also showed an overrepresentation of genes associated with the metabolism of carbohydrates, likely driven by the enrichment of nutrient resulting from aquaculture activities at the site. The results presented in this study can serve as a basis for understanding the structure and functional capacity of the microbial communities in the photic and aphotic zones/water layers of tropical man-made lakes.
    Matched MeSH terms: Bacteria/classification
  10. Structural and functional changes with depth in microbial communities in a tropical Malaysian peat swamp forest
    Jackson CR, Liew KC, Yule CM
    Microb Ecol, 2009 Apr;57(3):402-12.
    PMID: 18548182 DOI: 10.1007/s00248-008-9409-4
    Tropical peat swamp forests are important and endangered ecosystems, although little is known of their microbial diversity and ecology. We used molecular and enzymatic techniques to examine patterns in prokaryotic community structure and overall microbial activity at 0-, 10-, 20-, and 50-cm depths in sediments in a peat swamp forest in Malaysia. Denaturing gradient gel electrophoresis profiles of amplified 16S ribosomal ribonucleic acid (rRNA) gene fragments showed that different depths harbored different bacterial assemblages and that Archaea appeared to be limited to the deeper samples. Cloning and sequencing of longer 16S rRNA gene fragments suggested reduced microbial diversity in the deeper samples compared to the surface. Bacterial clone libraries were largely dominated by ribotypes affiliated with the Acidobacteria, which accounted for at least 27-54% of the sequences obtained. All of the sequenced representatives from the archaeal clone libraries were Crenarchaeota. Activities of microbial extracellular enzymes involved in carbon, nitrogen, and phosphorus cycling declined appreciably with depth, the only exception being peroxidase. These results show that tropical peat swamp forests are unusual systems with microbial assemblages dominated by members of the Acidobacteria and Crenarchaeota. Microbial communities show clear changes with depth, and most microbial activity is likely confined to populations in the upper few centimeters, the site of new leaf litter fall, rather than the deeper, older, peat layers.
    Matched MeSH terms: Bacteria/classification
  11. Distinct bacterial communities dominate tropical and temperate zone leaf litter
    Kim M, Kim WS, Tripathi BM, Adams J
    Microb Ecol, 2014 May;67(4):837-48.
    PMID: 24549745 DOI: 10.1007/s00248-014-0380-y
    Little is known of the bacterial community of tropical rainforest leaf litter and how it might differ from temperate forest leaf litter and from the soils underneath. We sampled leaf litter in a similarly advanced stage of decay, and for comparison, we also sampled the surface layer of soil, at three tropical forest sites in Malaysia and four temperate forest sites in South Korea. Illumina sequencing targeting partial bacterial 16S ribosomal ribonucleic acid (rRNA) gene revealed that the bacterial community composition of both temperate and tropical litter is quite distinct from the soils underneath. Litter in both temperate and tropical forest was dominated by Proteobacteria and Actinobacteria, while soil is dominated by Acidobacteria and, to a lesser extent, Proteobacteria. However, bacterial communities of temperate and tropical litter clustered separately from one another on an ordination. The soil bacterial community structures were also distinctive to each climatic zone, suggesting that there must be a climate-specific biogeographical pattern in bacterial community composition. The differences were also found in the level of diversity. The temperate litter has a higher operational taxonomic unit (OTU) diversity than the tropical litter, paralleling the trend in soil diversity. Overall, it is striking that the difference in community composition between the leaf litter and the soil a few centimeters underneath is about the same as that between leaf litter in tropical and temperate climates, thousands of kilometers apart. However, one substantial difference was that the leaf litter of two tropical forest sites, Meranti and Forest Research Institute Malaysia (FRIM), was overwhelmingly dominated by the single genus Burkholderia, at 37 and 23 % of reads, respectively. The 454 sequencing result showed that most Burkholderia species in tropical leaf litter belong to nonpathogenic "plant beneficial" lineages. The differences from the temperate zone in the bacterial community of tropical forest litter may be partly a product of its differing chemistry, although the unvarying climate might also play a role, as might interactions with other organisms such as fungi. The single genus Burkholderia may be seen as potentially playing a major role in decomposition and nutrient cycling in tropical forests, but apparently not in temperate forests.
    Matched MeSH terms: Bacteria/classification
  12. Rainforest Conversion to Rubber Plantation May Not Result in Lower Soil Diversity of Bacteria, Fungi, and Nematodes
    Kerfahi D, Tripathi BM, Dong K, Go R, Adams JM
    Microb Ecol, 2016 08;72(2):359-71.
    PMID: 27221090 DOI: 10.1007/s00248-016-0790-0
    Large areas of rainforest in Asia have been converted to plantations, with uncertain effects on soil biodiversity. Using standard metagenetic methods, we compared the soil biota of bacteria, fungi, and nematodes at three rainforest sites in Malaysia with two rubber plantation sites with similar soils and geology. We predicted the following: (1) that the rubber sites would have a lower α- and β-diversity than the rainforest sites, due to the monospecific canopy cover and intensive management with herbicides, pesticides, and fertilizers, and (2) that due to differences in the physical and biotic environment associated with cultivation, there would be distinct communities of bacteria, fungi, and nematodes. However, regarding (1), the results showed no consistent difference in α- and β-diversity of bacteria, fungi, or nematodes between rainforest and rubber plantation sites. It appears that conversion of rainforest to rubber plantations does not necessarily result in a decrease in diversity of soil biota. It may be that heterogeneity associated with the cultivation regimen compensates for loss of biotically imposed heterogeneity of the original rainforest. Regarding (2), as predicted there were statistically significant differences in community composition between rainforest and rubber plantation for bacteria, fungi, and nematodes. These differences could be related to a range of factors including light level, litter fall composition, pH, C and N, selecting a distinct set of soil taxa, and it is possible that this in itself would affect long-term soil function.
    Matched MeSH terms: Bacteria/classification*
  13. Microbial dynamics, metabolomic profiles, and the correlation between them during fermentation of serofluid dish
    Wei J, Ren W, Wang L, Liu M, Tian X, Ding G, et al.
    J Sci Food Agric, 2020 Dec;100(15):5627-5636.
    PMID: 32712996 DOI: 10.1002/jsfa.10690
    BACKGROUND: Serofluid dish, a traditional Chinese fermented food, possesses unique flavors and health beneficial effects. These properties are likely due to the sophisticated metabolic networks during fermentation, which are mainly driven by microbiota. However, the exact roles of metabolic pathways and the microbial community during this process remain equivocal.

    RESULTS: Here, we investigated the microbial dynamics by next-generation sequencing, and outlined a differential non-targeted metabolite profiling in the process of serofluid dish fermentation using the method of hydrophilic interaction liquid chromatography column with ultra-high-performance liquid chromatography-quadruple time-of-flight mass spectrometry. Lactobacillus was the leading genus of bacteria, while Pichia and Issatchenkia were the dominant fungi. They all accumulated during fermentation. In total, 218 differential metabolites were identified, of which organic acids, amino acids, sugar and sugar alcohols, fatty acids, and esters comprised the majority. The constructed metabolic network showed that tricarboxylic acid cycle, urea cycle, sugar metabolism, amino acids metabolism, choline metabolism, and flavonoid metabolism were regulated by the fermentation. Furthermore, correlation analysis revealed that the leading fungi, Pichia and Issatchenkia, were linked to organic acids, amino acid and sugar metabolism, flavonoids, and several other flavor and functional components. Antibacterial tests indicated the antibacterial effect of serofluid soup against Salmonella and Staphylococcus.

    CONCLUSION: This work provides new insights into the complex microbial and metabolic networks during serofluid dish fermentation, and a theoretical basis for the optimization of its industrial production. © 2020 Society of Chemical Industry.

    Matched MeSH terms: Bacteria/classification
  14. Fulltext An eight-year review of blood culture and susceptibility among sepsis cases in an emergency department in Northeastern Malaysia
    Hashairi F, Hasan H, Azlan K, Deris ZZ
    Trop Biomed, 2011 Dec;28(3):599-605.
    PMID: 22433889 MyJurnal
    An understanding of common pathogens and their antibiotic sensitivity patterns is critical for proper management of sepsis in Emergency Department (ED). The goal of the study was to identify common organisms isolated from blood cultures of patients attended to ED and their antimicrobial susceptibility. Beginning from 2002, all cases of positive blood culture collected by the ED, Hospital Universiti Sains Malaysia (HUSM) were recorded and analysed. Over the period of eight years, we documented 995 cases of positive blood cultures. Of these samples, 549 (55.2%) were Gram-negative bacteria; 419 (42.1%) were Gram-positive bacteria; 10 (1.0%) were anaerobic organisms; 10 (1.0%) were fungus; and 7 (0.7%) cases were mixed organisms. Gram-negative bacteria were observed to develop more resistance to antimicrobial agents, especially those commonly used in an outpatient setting with less than 80% sensitivity to ampicillin, cotrimoxazole and ciprofloxacin. By contrast, there has been no marked change in the sensitivity trends of Gram-positive bacteria over the same period. In conclusion, ED physicians are more equipped to initiate empirical antimicrobial therapy especially when dealing with possibility of Gram-negative sepsis.
    Study site: Emergency department, Hospital Universiti Sains Malaysia (HUSM), Kelantan, Malaysia
    Matched MeSH terms: Bacteria/classification
  15. Fulltext Prospective surveillance of nosocomial device-associated bacteremia in three adult intensive units in Malaysia
    Gopal Katherason S, Naing L, Jaalam K, Kamarul Iman Musa K, Nik Abdullah NM, Aiyar S, et al.
    Trop Biomed, 2010 Aug;27(2):308-16.
    PMID: 20962730 MyJurnal
    Nosocomial blood stream infection (or nosocomial bacteremia) is a common problem in hospitals worldwide, including Malaysia. A three-year prospective cohort study (October 2003-March 2007) of the incidences, risk factors, and patterns of the microorganisms causing bacteremia was conducted using a validated surveillance form in three intensive care units (ICUs) in Malaysia. Center for Disease Control criteria were used to diagnose bacteremia. Patients were monitored from admission until the end point of study, which was the first detection of bacteremia in the blood in each patient. The frequency of occurrence of bacteremia with clinical symptoms was 10.7% (n=23). Bacteremia was observed to occur within a mean length of stay of 10 days in ICU. The rate of device-related infection was 10.4% per device utilization days with a device utilization rate of 95.9%/1000 patient days. The total number of patient days was 2309 and the period of device utilization was 2211 days. The common bacteria detected were extended-spectrum beta-lactamases (ESBLs) Klebsiella pneumoniae (n=6); Pseudomonas aeruginosa (n=6); Acinetobacter species (n=5); Methicillin-resistant Staphylococcus aureus (MRSA)(n=3); and (non- ESBL) Klebsiella pneumoniae (n=2). Multivariable analysis using Cox Proportional Hazard Model showed that the predictors for developing bacteremia were cancer, MRSA carriage, duration of central venous catheter (CVC) infusion, frequency change of CVC, and the administration of hydrocortisone drugs. These results indicate that a combination of nursing and medical interventions as well as patients' severity of illness could lead to bacteremia in ICU. Strategic implementation of quality assurance measures in ICUs could help to control this problem.
    Matched MeSH terms: Bacteria/classification
  16. Increasing atmospheric deposition nitrogen and ammonium reduced microbial activity and changed the bacterial community composition of red paddy soil
    Zhou F, Cui J, Zhou J, Yang J, Li Y, Leng Q, et al.
    Sci Total Environ, 2018 Aug 15;633:776-784.
    PMID: 29602116 DOI: 10.1016/j.scitotenv.2018.03.217
    Atmospheric deposition nitrogen (ADN) increases the N content in soil and subsequently impacts microbial activity of soil. However, the effects of ADN on paddy soil microbial activity have not been well characterized. In this study, we studied how red paddy soil microbial activity responses to different contents of ADN through a 10-months ADN simulation on well managed pot experiments. Results showed that all tested contents of ADN fluxes (27, 55, and 82kgNha-1 when its ratio of NH4+/NO3--N (RN) was 2:1) enhanced the soil enzyme activity and microbial biomass carbon and nitrogen and 27kgNha-1 ADN had maximum effects while comparing with the fertilizer treatment. Generally, increasing of both ADN flux and RN (1:2, 1:1 and 2:1 with the ADN flux of 55kgNha-1) had similar reduced effects on microbial activity. Furthermore, both ADN flux and RN significantly reduced soil bacterial alpha diversity (p<0.05) and altered bacterial community structure (e.g., the relative abundances of genera Dyella and Rhodoblastus affiliated to Proteobacteria increased). Redundancy analysis demonstrated that ADN flux and RN were the main drivers in shaping paddy soil bacteria community. Overall, the results have indicated that increasing ADN flux and ammonium reduced soil microbial activity and changed the soil bacterial community. The finding highlights how paddy soil microbial community response to ADN and provides information for N management in paddy soil.
    Matched MeSH terms: Bacteria/classification
  17. High Diversity of Bacterial Communities in Developmental Stages of Bactrocera carambolae (Insecta: Tephritidae) Revealed by Illumina MiSeq Sequencing of 16S rRNA Gene
    Yong HS, Song SL, Chua KO, Lim PE
    Curr Microbiol, 2017 Sep;74(9):1076-1082.
    PMID: 28642971 DOI: 10.1007/s00284-017-1287-x
    Bactrocera carambolae is a highly polyphagous fruit pest of agricultural importance. This study reports the bacterial communities associated with the developmental stages of B. carambolae. The microbiota of the developmental stages were investigated by targeted 16S rRNA gene (V3-V4 region) sequencing using the Illumina MiSeq. At 97% similarity, there were 19 bacterial phyla and unassigned bacteria, comprising 39 classes, 86 orders, 159 families and 311 genera. The bacterial composition varied among the specimens of developmental stage and across developmental stages as well as exuviae. Four phyla of bacteria (with relative abundance of ≥1% in at least one specimen)-Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria-were recovered from the larva, pupa, adult stages and exuviae. Proteobacteria was the predominant phylum in all the developmental stages as well as the exuviae. Enterobacteriaceae (Proteobacteria) was the predominant family in the adult flies while the family [Weeksellaceae] (Bacteroidetes) was predominant in the larval and pupal stages. Among the genera occurring in more than one developmental stage of B. carambolae, Erwinia was more abundant in the larval stage, Halomonas more abundant in adult female, Stenotrophomonas more abundant in adult male, and Chryseobacterium more abundant in the larval and pupal stages. The results indicate transmission of bacteria OTUs from immatures to the newly emerged adults, and from exuviae to the environment.
    Matched MeSH terms: Bacteria/classification*
  18. Heterologous expression of the tetracycline resistance gene tetX to enhance degradability and safety in doxycycline degradation
    Wen X, Huang J, Cao J, Xu J, Mi J, Wang Y, et al.
    Ecotoxicol Environ Saf, 2020 Mar 15;191:110214.
    PMID: 31968275 DOI: 10.1016/j.ecoenv.2020.110214
    Microbial remediation has the potential to inexpensively yet effectively decontaminate and restore contaminated environments, but the virulence of pathogens and risk of resistance gene transmission by microorganisms during antibiotic removal often limit its implementation. Here, a cloned tetX gene with clear evolutionary history was expressed to explore doxycycline (DOX) degradation and resistance variation during the degradation process. Phylogenetic analysis of tetX genes showed high similarity with those of pathogenic bacteria, such as Riemerella sp. and Acinetobacter sp. Successful tetX expression was performed in Escherichia coli and confirmed by SDS-PAGE and Western blot. Our results showed that 95.0 ± 1.0% of the DOX (50 mg/L) was degraded by the recombinant strain (ETD-1 with tetX) within 48 h, which was significantly higher than that for the control (38.9 ± 8.7%) and the empty plasmid bacteria (8.8 ± 5.1%) (P  0.05). The efficient and safe DOX-degrading capacity of the recombinant strain ETD-1 makes it valuable and promising for antibiotic removal in the environment.
    Matched MeSH terms: Bacteria/classification
  19. Fulltext Dynamics of Microbial Populations Responsible for Biodegradation during the Full-Scale Treatment of Palm Oil Mill Effluent
    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
  20. Fulltext Microbial Diversity in Decaying Oil Palm Empty Fruit Bunches (OPEFB) and Isolation of Lignin-degrading Bacteria from a Tropical Environment
    Tahir AA, Mohd Barnoh NF, Yusof N, Mohd Said NN, Utsumi M, Yen AM, et al.
    Microbes Environ, 2019 Jun 27;34(2):161-168.
    PMID: 31019143 DOI: 10.1264/jsme2.ME18117
    Oil palm empty fruit bunches (OPEFB) are the most abundant, inexpensive, and environmentally friendly lignocellulosic biomass in Malaysia. Investigations on the microbial diversity of decaying OPEFB may reveal microbes with complex enzymes that have the potential to enhance the conversion of lignocellulose into second-generation biofuels as well as the production of other value-added products. In the present study, fungal and bacterial diversities in decaying OPEFB were identified using Illumina MiSeq sequencing of the V3 region of the 16S rRNA gene and V4 region of the 18S rRNA gene. Fungal diversity in decaying OPEFB was dominated by the phylum Ascomycota (14.43%), while most of the bacterial sequences retrieved belonged to Proteobacteria (76.71%). Three bacterial strains isolated from decaying OPEFB, designated as S18, S20, and S36, appeared to grow with extracted OPEFB-lignin and Kraft lignin (KL) as the sole carbon source. 16S rRNA gene sequencing identified the 3 isolates as Paenibacillus sp.. The molecular weight distribution of KL before and after degradation showed significant depolymerization when treated with bacterial strains S18, S20, and S36. The presence of low-molecular-weight lignin-related compounds, such as vanillin and 2-methoxyphenol derivatives, which were detected by a GC-MS analysis, confirmed the KL-degrading activities of isolated Paenibacillus strains.
    Matched MeSH terms: Bacteria/classification
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