Displaying publications 1 - 20 of 199 in total

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  1. Ikryannikova LN, Shitikov EA, Zhivankova DG, Il'ina EN, Edelstein MV, Govorun VM
    J Microbiol Methods, 2008 Dec;75(3):385-91.
    PMID: 18694787 DOI: 10.1016/j.mimet.2008.07.005
    A minisequencing method based on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS) was developed for rapid identification of single nucleotide polymorphisms at bla(TEM) gene codons 104, 164 and 238 associated with extended-spectrum activity on TEM-type beta-lactamases. The method was validated by testing the Escherichia coli and Klebsiella pneumoniae strains possessing the known bla(TEM) gene sequences.
    Matched MeSH terms: Bacterial Proteins/metabolism
  2. Tan SH, Normi YM, Leow AT, Salleh AB, Karjiban RA, Murad AM, et al.
    BMC Struct Biol, 2014 Mar 19;14:11.
    PMID: 24641837 DOI: 10.1186/1472-6807-14-11
    BACKGROUND: At least a quarter of any complete genome encodes for hypothetical proteins (HPs) which are largely non-similar to other known, well-characterized proteins. Predicting and solving their structures and functions is imperative to aid understanding of any given organism as a complete biological system. The present study highlights the primary effort to classify and cluster 1202 HPs of Bacillus lehensis G1 alkaliphile to serve as a platform to mine and select specific HP(s) to be studied further in greater detail.

    RESULTS: All HPs of B. lehensis G1 were grouped according to their predicted functions based on the presence of functional domains in their sequences. From the metal-binding group of HPs of the cluster, an HP termed Bleg1_2507 was discovered to contain a thioredoxin (Trx) domain and highly-conserved metal-binding ligands represented by Cys69, Cys73 and His159, similar to all prokaryotic and eukaryotic Sco proteins. The built 3D structure of Bleg1_2507 showed that it shared the βαβαββ core structure of Trx-like proteins as well as three flanking β-sheets, a 310 -helix at the N-terminus and a hairpin structure unique to Sco proteins. Docking simulations provided an interesting view of Bleg1_2507 in association with its putative cytochrome c oxidase subunit II (COXII) redox partner, Bleg1_2337, where the latter can be seen to hold its partner in an embrace, facilitated by hydrophobic and ionic interactions between the proteins. Although Bleg1_2507 shares relatively low sequence identity (47%) to BsSco, interestingly, the predicted metal-binding residues of Bleg1_2507 i.e. Cys-69, Cys-73 and His-159 were located at flexible active loops similar to other Sco proteins across biological taxa. This highlights structural conservation of Sco despite their various functions in prokaryotes and eukaryotes.

    CONCLUSIONS: We propose that HP Bleg1_2507 is a Sco protein which is able to interact with COXII, its redox partner and therefore, may possess metallochaperone and redox functions similar to other documented bacterial Sco proteins. It is hoped that this scientific effort will help to spur the search for other physiologically relevant proteins among the so-called "orphan" proteins of any given organism.

    Matched MeSH terms: Bacterial Proteins/metabolism*
  3. Su YC, Wan KL, Mohamed R, Nathan S
    Microbes Infect., 2008 Oct;10(12-13):1335-45.
    PMID: 18761419 DOI: 10.1016/j.micinf.2008.07.034
    Burkholderia pseudomallei is the etiological agent of melioidosis, a severe infectious disease of humans and animals. The role of the bacterium's proteins expressed in vivo during human melioidosis continues to remain an enigma. This study's aim was to identify B. pseudomallei target proteins that elicit the humoral immune response in infected humans. A small insert genomic expression library was constructed and immunoscreened to identify peptides that reacted exclusively with melioidosis patients' sera. Sero-positive clones expressing immunogenic peptides were sequenced and annotated, and shown to represent 109 proteins involved in bacterial cell envelope biogenesis, cell motility and secretion, transcription, amino acid, ion and protein metabolism, energy production, DNA repair and unknown hypothetical proteins. Western blot analysis of three randomly selected full-length immunogenic polypeptides with patients' sera verified the findings of the immunome screening. The patients' humoral immune response to the 109 proteins suggests the induction or significant upregulation of these proteins in vivo during human infection and thus may play a role in the pathogenesis of B. pseudomallei. Identification of B. pseudomallei immunogens has shed new light on the elucidation of the bacterium's pathogenesis mechanism and disease severity. These immunogens can be further evaluated as prophylactic and serodiagnostic candidates as well as drug targets.
    Matched MeSH terms: Bacterial Proteins/metabolism*
  4. Zainudin MHM, Mustapha NA, Hassan MA, Bahrin EK, Tokura M, Yasueda H, et al.
    Sci Rep, 2019 09 19;9(1):13526.
    PMID: 31537863 DOI: 10.1038/s41598-019-50126-y
    A thermophilic Thermobifida fusca strain UPMC 901, harboring highly thermostable cellulolytic activity, was successfully isolated from oil palm empty fruit bunch compost. Its endoglucanase had the highest activity at 24 hours of incubation in carboxymethyl-cellulose (CMC) and filter paper. A maximum endoglucanase activity of 0.9 U/mL was achieved at pH 5 and 60 °C using CMC as a carbon source. The endoglucanase properties were further characterized using crude enzyme preparations from the culture supernatant. Thermal stability indicated that the endoglucanase activity was highly stable at 70 °C for 24 hours. Furthermore, the activity was found to be completely maintained without any loss at 50 °C and 60 °C for 144 hours, making it the most stable than other endoglucanases reported in the literature. The high stability of the endoglucanase at an elevated temperature for a prolonged period of time makes it a suitable candidate for the biorefinery application.
    Matched MeSH terms: Bacterial Proteins/metabolism
  5. Ng HF, Tan JL, Zin T, Yap SF, Ngeow YF
    J Med Microbiol, 2018 Dec;67(12):1676-1681.
    PMID: 30351265 DOI: 10.1099/jmm.0.000857
    In this study, we characterized 7C, a spontaneous mutant selected from tigecycline-susceptible Mycobacterium abscessus ATCC 19977. Whole-genome sequencing (WGS) was used to identify possible resistance determinants in this mutant. Compared to the wild-type, 7C demonstrated resistance to tigecycline as well as cross-resistance to imipenem, and had a slightly retarded growth rate. WGS and subsequent biological verifications showed that these phenotypes were caused by a point mutation in MAB_3542c, which encodes an RshA-like protein. In Mycobacterium tuberculosis, RshA is an anti-sigma factor that negatively regulates the heat/oxidative stress response mechanisms. The MAB_3542c mutation may represent a novel determinant of tigecycline resistance. We hypothesize that this mutation may dysregulate the stress-response pathways which have been shown to be linked to antibiotic resistance in previous studies.
    Matched MeSH terms: Bacterial Proteins/metabolism*
  6. Kamarudin NH, Rahman RN, Ali MS, Leow TC, Basri M, Salleh AB
    Protein J, 2014 Jun;33(3):296-307.
    PMID: 24777627 DOI: 10.1007/s10930-014-9560-3
    The gene encoding a cold-adapted, organic solvent stable lipase from a local soil-isolate, mesophilic Staphylococcus epidermidis AT2 was expressed in a prokaryotic system. A two-step purification of AT2 lipase was achieved using butyl sepharose and DEAE sepharose column chromatography. The final recovery and purification fold were 47.09 % and 3.45, respectively. The molecular mass of the purified lipase was estimated to be 43 kDa. AT2 lipase was found to be optimally active at pH 8 and stable at pH 6-9. Interestingly, this enzyme demonstrated remarkable stability at cold temperature (<30 °C) and exhibited optimal activity at a temperature of 25 °C. A significant enhancement of the lipolytic activity was observed in the presence of Ca(2+), Tween 60 and Tween 80. Phenylmethylsulfonylfluoride, a well known serine inhibitor did not cause complete inhibition of the enzymatic activity. AT2 lipase exhibited excellent preferences towards long chain triglycerides and natural oils. The lipolytic activity was stimulated by dimethylsulfoxide and diethyl ether, while more than 50 % of its activity was retained in methanol, ethanol, acetone, toluene, and n-hexane. Taken together, AT2 lipase revealed highly attractive biochemical properties especially because of its stability at low temperature and in organic solvents.
    Matched MeSH terms: Bacterial Proteins/metabolism
  7. Rahman RN, Mahamad S, Salleh AB, Basri M
    J Ind Microbiol Biotechnol, 2007 Jul;34(7):509-17.
    PMID: 17492323
    Five out of the nine benzene-toulene-ethylbenzene-xylene (BTEX) tolerant bacteria that demonstrated high protease activity on skim milk agar were isolated. Among them, isolate 115b identified as Bacillus pumilus exhibited the highest protease production. The protease produced was stable in 25% (v/v) benzene and toluene and it was activated 1.7 and 2.5- fold by n-dodecane and n-tetradecane, respectively. The gene encoding the organic solvent tolerant protease was cloned and its nucleotide sequence determined. Sequence analysis revealed an open reading frame (ORF) of 1,149 bp that encoded a polypeptide of 383 amino acid residues. The polypeptide composed of 29 residues of signal peptide, a propeptide of 79 residues and a mature protein of 275 amino acids with a calculated molecular mass of 27,846 Da. This is the only report available to date on organic solvent tolerant protease from B. pumilus.
    Matched MeSH terms: Bacterial Proteins/metabolism*
  8. BangaSingh KK, Nisha M, Lau HY, Ravichandran M, Salleh MZ
    Microb Pathog, 2016 Feb;91:123-8.
    PMID: 26706344 DOI: 10.1016/j.micpath.2015.12.004
    Virulence of Shigella is attributed to the genes presence in chromosome or in the megaplasmid. The apy gene which is located in the megaplasmid of Shigella species encodes for apyrase enzyme, a pathogenesis-associated enzyme causing mitochondrial damage and host cell death. In this study we constructed an apy mutant of Shigella flexneri by insertional activation using a kanamycin resistant gene cassette. The wild type apy gene of S. flexneri 2a was PCR amplified, cloned and mutated with insertion of kanamycin resistant gene cassette (aphA). The mutated construct (apy: aphA) was subcloned into a conjugative suicidal vector (pWM91) at the unique Sma1 and Sac1 sites. The mutation of the wild apy gene in the construct was confirmed by DNA sequencing. The mutated construct was introduced into wild type S. flexneri 2a by conjugation with Escherichia coli. After undergoing homologous recombination, the wild apy gene was deleted from the construct using the sucrose selection method. Non-functional activity of the apyrase enzyme in the constructed strain by colorimetric test indicated the successful mutation of the apyrase enzyme. This strain with mutated apy gene was evaluated for its protective efficacy using the guinea pig keratoconjunctivitis model. The strain was Sereny negative and it elicited a significant protection following challenge with wild S. flexneri strain. This apy mutant strain will form a base for the development of a vaccine target for shigellosis.
    Matched MeSH terms: Bacterial Proteins/metabolism*
  9. Al-Maleki AR, Mariappan V, Vellasamy KM, Tay ST, Vadivelu J
    PLoS One, 2015;10(5):e0127398.
    PMID: 25996927 DOI: 10.1371/journal.pone.0127398
    Burkholderia pseudomallei primary diagnostic cultures demonstrate colony morphology variation associated with expression of virulence and adaptation proteins. This study aims to examine the ability of B. pseudomallei colony variants (wild type [WT] and small colony variant [SCV]) to survive and replicate intracellularly in A549 cells and to identify the alterations in the protein expression of these variants, post-exposure to the A549 cells. Intracellular survival and cytotoxicity assays were performed followed by proteomics analysis using two-dimensional gel electrophoresis. B. pseudomallei SCV survive longer than the WT. During post-exposure, among 259 and 260 protein spots of SCV and WT, respectively, 19 were differentially expressed. Among SCV post-exposure up-regulated proteins, glyceraldehyde 3-phosphate dehydrogenase, fructose-bisphosphate aldolase (CbbA) and betaine aldehyde dehydrogenase were associated with adhesion and virulence. Among the down-regulated proteins, enolase (Eno) is implicated in adhesion and virulence. Additionally, post-exposure expression profiles of both variants were compared with pre-exposure. In WT pre- vs post-exposure, 36 proteins were differentially expressed. Of the up-regulated proteins, translocator protein, Eno, nucleoside diphosphate kinase (Ndk), ferritin Dps-family DNA binding protein and peptidyl-prolyl cis-trans isomerase B were implicated in invasion and virulence. In SCV pre- vs post-exposure, 27 proteins were differentially expressed. Among the up-regulated proteins, flagellin, Eno, CbbA, Ndk and phenylacetate-coenzyme A ligase have similarly been implicated in adhesion, invasion. Protein profiles differences post-exposure provide insights into association between morphotypic and phenotypic characteristics of colony variants, strengthening the role of B. pseudomallei morphotypes in pathogenesis of melioidosis.
    Matched MeSH terms: Bacterial Proteins/metabolism*
  10. Weng PL, Ramli R, Hamat RA
    PMID: 31533204 DOI: 10.3390/ijerph16183439
    Enterococci are commonly found in humans, animals and environments. Their highly adaptive mechanisms are related to several virulent determinants and their ability to resist antibiotics. Data on the relationship between the esp gene, biofilm formation and antibiotic susceptibility profiles may differ between countries. This cross-sectional study was conducted to determine the proportion of esp gene and biofilm formation among Enterococcus faecalis and Enterococcus faecium clinical isolates. We also investigated the possible association between the esp gene with antibiotic susceptibility patterns and biofilm formation. The isolates were collected from clinical samples and identified using biochemical tests and 16SRNA. Antibiotic susceptibility patterns and a biofilm assay were conducted according to the established guidelines. Molecular detection by PCR was used to identify the esp gene using established primers. In total, 52 and 28 of E. faecalis and E. faecium were identified, respectively. E. faecium exhibited higher resistance rates compared to E. faecalis as follows: piperacillin/tazobactam (100% versus 1.9%), ampicillin (92.8% versus 1.9%), high-level gentamicin resistance (HLGR) (89.3% versus 25.0%) and penicillin (82.1% versus 7.7%). E. faecium produced more biofilms than E. faecalis (59.3% versus 49.0%). E. faecium acquired the esp gene more frequently than E. faecalis (78.6% versus 46.2%). Interestingly, the associations between ampicillin and tazobactam/piperacillin resistance with the esp gene were statistically significant (X2 = 4.581, p = 0.027; and X2 = 6.276, p = 0.012, respectively). Our results demonstrate that E. faecium exhibits high rates of antimicrobial resistance, esp gene acquisition and biofilm formation. These peculiar traits of E. faecium may have implications for the management of enterococcal infections in hospitals. Thus, concerted efforts by all parties in establishing appropriate treatment and effective control measures are warranted in future.
    Matched MeSH terms: Bacterial Proteins/metabolism
  11. Khalilpour A, Santhanam A, Wei LC, Saadatnia G, Velusamy N, Osman S, et al.
    Asian Pac J Cancer Prev, 2013;14(3):1635-42.
    PMID: 23679248
    Helicobacter pylori antigen was prepared from an isolate from a patient with a duodenal ulcer. Serum samples were obtained from culture-positive H. pylori infected patients with duodenal ulcers, gastric ulcers and gastritis (n=30). As controls, three kinds of sera without detectable H. pylori IgG antibodies were used: 30 from healthy individuals without history of gastric disorders, 30 from patients who were seen in the endoscopy clinic but were H. pylori culture negative and 30 from people with other diseases. OFF-GEL electrophoresis, SDS-PAGE and Western blots of individual serum samples were used to identify protein bands with good sensitivity and specificity when probed with the above sera and HRP-conjugated anti-human IgG. Four H. pylori protein bands showed good (≥ 70%) sensitivity and high specificity (98-100%) towards anti-Helicobacter IgG antibody in culture- positive patients sera and control sera, respectively. The identities of the antigenic proteins were elucidated by mass spectrometry. The relative molecular weights and the identities of the proteins, based on MALDI TOF/ TOF, were as follows: CagI (25 kDa), urease G accessory protein (25 kDa), UreB (63 kDa) and proline/pyrroline- 5-carboxylate dehydrogenase (118 KDa). These identified proteins, singly and/or in combinations, may be useful for diagnosis of H. pylori infection in patients.
    Matched MeSH terms: Bacterial Proteins/metabolism
  12. Moo CL, Osman MA, Yang SK, Yap WS, Ismail S, Lim SH, et al.
    Sci Rep, 2021 10 21;11(1):20824.
    PMID: 34675255 DOI: 10.1038/s41598-021-00249-y
    Antimicrobial resistance remains one of the most challenging issues that threatens the health of people around the world. Plant-derived natural compounds have received considerable attention for their potential role to mitigate antibiotic resistance. This study was carried out to assess the antimicrobial activity and mode of action of a monoterpene, 1,8-cineol (CN) against carbapenemase-producing Klebsiella pneumoniae (KPC-KP). Results showed that resazurin microplate assay and time-kill analysis revealed bactericidal effects of CN at 28.83 mg/mL. Zeta potential showed that CN increased the surface charge of bacteria and an increase of outer membrane permeability was also detected. CN was able to cause leakage of proteins and nucleic acids in KPC-KP cells upon exposure to CN and ethidium bromide influx/efflux experiment showed the uptake of ethidium bromide into the cell; this was attributed to membrane damage. CN was also found to induce oxidative stress in CN-treated KPC-KP cells through generation of reactive oxygen species which initiated lipid peroxidation and thus damaging the bacterial cell membrane. Scanning and transmission electron microscopies further confirmed the disruption of bacterial cell membrane and loss of intracellular materials. In this study, we demonstrated that CN induced oxidative stress and membrane damage resulting in KPC-KP cell death.
    Matched MeSH terms: Bacterial Proteins/metabolism*
  13. Khosravi Y, Vellasamy KM, Mariappan V, Ng SL, Vadivelu J
    ScientificWorldJournal, 2014;2014:132971.
    PMID: 25379514 DOI: 10.1155/2014/132971
    Burkholderia pseudomallei, the causative agent of melioidosis, is intrinsically resistant to many antibiotics. Ceftazidime (CAZ), the synthetic β-lactam, is normally used as the first-line antibiotic therapy for treatment of melioidosis. However, acquired CAZ resistance can develop in vivo during treatment with CAZ, leading to mortality if therapy is not switched to a different antibiotic(s) in a timely manner. In this study, susceptibilities of 81 B. pseudomallei isolates to nine different antimicrobial agents were determined using the disk diffusion method, broth microdilution test and Etest. Highest percentage of susceptibility was demonstrated to CAZ, amoxicillin/clavulanic acid, meropenem, imipenem, and trimethoprim/sulfamethoxazole. Although these drugs demonstrated the highest percentage of susceptibility in B. pseudomallei, the overall results underline the importance of the emergence of resistance in this organism. PCR results showed that, of the 81 B. pseudomallei, six multidrug resistant (MDR) isolates carried bpeB, amrB, and BPSS1119 and penA genes. Genotyping of the isolates using random amplified polymorphic DNA analysis showed six different PCR fingerprinting patterns generated from the six MDR isolates clusters (A) and eight PCR fingerprinting patterns generated for the remaining 75 non-MDR isolates clusters (B).
    Matched MeSH terms: Bacterial Proteins/metabolism
  14. Idris SN, Desa MN, Aziz MN, Taib NM
    PMID: 23082561
    This study was conducted to determine the antibiotic susceptibility pattern and distribution of exoU and exoS among 44 clinical isolates of P. aeruginosa collected from different patients over a 3-month period in 2010 at a major Malaysian hospital. Susceptibility data by disk diffusion method for cefepime (30 microg), ceftazidime (30 microg), gentamicin (10 microg), piperacillin-tazobactam (100/10 microg) and ciprofloxacin (5 microg) were available for 38 isolates. Resistance to ceftazidime and piperacillin-tazobactam was the most common (74%) with five isolates not susceptible to three or more different antibiotics. PCR detection of exoU and exoS of all 44 isolates showed the former gene to be present in 18 and exoS in 41. In analyzing the two genes together, 17 isolates were detected for exoU and exoS with only two being negative for both genes. Only one isolate was detected for exoU alone whereas 24 for exoS alone. Distribution of the genes in relation to antibiotic susceptibility was inapplicable due to the majority of the isolates having similar susceptibility patterns, but the tendency of exoU-carrying isolates to be present in male patients (83%) and respiratory sites (61%) was observed (p < 0.050). The finding warrants further investigation in a larger sample of isolates.\

    Study site: Hospital Kuala Lumpur (HKL)
    Matched MeSH terms: Bacterial Proteins/metabolism*
  15. Alexeev D, Kostrjukova E, Aliper A, Popenko A, Bazaleev N, Tyakht A, et al.
    J Proteome Res, 2012 Jan 1;11(1):224-36.
    PMID: 22129229 DOI: 10.1021/pr2008626
    To date, no genome of any of the species from the genus Spiroplasma has been completely sequenced. Long repetitive sequences similar to mobile units present a major obstacle for current genome sequencing technologies. Here, we report the assembly of the Spiroplasma melliferum KC3 genome into 4 contigs, followed by proteogenomic annotation and metabolic reconstruction based on the discovery of 521 expressed proteins and comprehensive metabolomic profiling. A systems approach allowed us to elucidate putative pathogenicity mechanisms and to discover major virulence factors, such as Chitinase utilization enzymes and toxins never before reported for insect pathogenic spiroplasmas.
    Matched MeSH terms: Bacterial Proteins/metabolism
  16. Ang SS, Salleh AB, Chor LT, Normi YM, Tejo BA, Rahman MBA, et al.
    Protein J, 2018 04;37(2):180-193.
    PMID: 29508210 DOI: 10.1007/s10930-018-9764-z
    The bioconversion of vitamin D3 catalyzed by cytochrome P450 (CYP) requires 25-hydroxylation and subsequent 1α-hydroxylation to produce the hormonal activated 1α,25-dihydroxyvitamin D3. Vitamin D3 25-hydroxylase catalyses the first step in the vitamin D3 biosynthetic pathway, essential in the de novo activation of vitamin D3. A CYP known as CYP107CB2 has been identified as a novel vitamin D hydroxylase in Bacillus lehensis G1. In order to deepen the understanding of this bacterial origin CYP107CB2, its detailed biological functions as well as biochemical characteristics were defined. CYP107CB2 was characterized through the absorption spectral analysis and accordingly, the enzyme was assayed for vitamin D3 hydroxylation activity. CYP-ligand characterization and catalysis optimization were conducted to increase the turnover of hydroxylated products in an NADPH-regenerating system. Results revealed that the over-expressed CYP107CB2 protein was dominantly cytosolic and the purified fraction showed a protein band at approximately 62 kDa on SDS-PAGE, indicative of CYP107CB2. Spectral analysis indicated that CYP107CB2 protein was properly folded and it was in the active form to catalyze vitamin D3 reaction at C25. HPLC and MS analysis from a reconstituted enzymatic reaction confirmed the hydroxylated products were 25-hydroxyitamin D3 and 1α,25-dihydroxyvitamin D3 when the substrates vitamin D3 and 1α-hydroxyvitamin D3 were used. Biochemical characterization shows that CYP107CB2 performed hydroxylation activity at 25 °C in pH 8 and successfully increased the production of 1α,25-dihydroxyvitamin D3 up to four fold. These findings show that CYP107CB2 has a biologically relevant vitamin D3 25-hydroxylase activity and further suggest the contribution of CYP family to the metabolism of vitamin D3.
    Matched MeSH terms: Bacterial Proteins/metabolism
  17. Nallapan Maniyam M, Sjahrir F, Ibrahim AL, Cass AE
    J Gen Appl Microbiol, 2013;59(6):393-404.
    PMID: 24492598
    A Rhodococcus sp. UKMP-5M isolate was shown to detoxify cyanide successfully, suggesting the presence of an intrinsic property in the bacterium which required no prior cyanide exposure for induction of this property. However, in order to promote growth, Rhodococcus sp. UKMP-5M was fully acclimatized to cyanide after 7 successive subcultures in 0.1 mM KCN for 30 days. To further shorten the lag phase and simultaneously increase the tolerance towards higher cyanide concentrations, the bacterium was induced with various nitrile compounds sharing a similar degradatory pathway to cyanide. Acetonitrile emerged as the most favored inducer and the induced cells were able to degrade 0.1 mM KCN almost completely within 18 h. With the addition of subsequent aliquots of 0.1 mM KCN a shorter period for complete removal of cyanide was required, which proved to be advantageous economically. Both resting cells and crude enzyme of Rhodococcus sp. UKMP-5M were able to biodegrade cyanide to ammonia and formate without the formation of formamide, implying the identification of a simple hydrolytic cyanide degradation pathway involving the enzyme cyanidase. Further verification with SDS-PAGE revealed that the molecular weight of the active enzyme was estimated to be 38 kDa, which is consistent with previously reported cyanidases. Since the recent advancement in the application of biological methods in treating cyanide-bearing wastewater has been promising, the discovery of this new bacterium will add value by diversifying the existing microbial populations capable of cyanide detoxification.
    Matched MeSH terms: Bacterial Proteins/metabolism
  18. Widyasti E, Shikata A, Hashim R, Sulaiman O, Sudesh K, Wahjono E, et al.
    Enzyme Microb Technol, 2018 Apr;111:21-28.
    PMID: 29421033 DOI: 10.1016/j.enzmictec.2017.12.009
    Oil palm trunk (OPT) is one of the most promising lignocellulosic bioresources. To develop effective biodegradation, thermophilic, anaerobic microorganisms were screened from bovine manure compost using fibrillated OPT (f-OPT) pretreated by wet disk milling as the substrate. One thermophilic, anaerobic bacterium, strain CL-2, whose 16S rDNA gene has 98.6% sequence identity with that of Caldicoprobacter faecale DSM 20678T, exhibited high degradation activity (32.7% reduction in total dry solids of f-OPT). Strain CL-2 did not use cellulose as a carbon source, but used hemicelluloses such as xylan, arabinoxylan, starch and pectin at 70 °C. Phylogenetic and morphologic analyses and the polysaccharide use suggest that CL-2 may be classified as a novel species of Caldicoprobacter, named Caldicoprobacter sp. CL-2. To characterize enzymatic activities of CL-2, extracellular enzymes were prepared from culture broth using beechwood xylan as the carbon source. The extracellular enzymes showed high xylanase activity, but low cellulase activity, suggesting that f-OPT degradation may depend on xylanase activity. To understand the xylanase system of CL-2, a major xylanase was cloned and characterized. The xylanase (CalXyn11A) had a modular structure consisting of a glycoside hydrolase (GH) family-11 domain and a family 36 carbohydrate-binding module. CalXyn11A did not show f-OPT degradation activity, but a strong synergistic effect was observed when CalXyn11A was added to the extracellular enzyme preparation. These results indicate that, rather than working alone, CalXyn11A has an important role in enhancing total lignocellulose degradation activity by cooperation with other GHs.
    Matched MeSH terms: Bacterial Proteins/metabolism*
  19. Nyanasegran PK, Nathan S, Firdaus-Raih M, Muhammad NAN, Ng CL
    J Microbiol Biotechnol, 2023 Jan 28;33(1):15-27.
    PMID: 36451302 DOI: 10.4014/jmb.2207.07032
    The incidence of melioidosis cases caused by the gram-negative pathogen Burkholderia pseudomallei (BP) is seeing an increasing trend that has spread beyond its previously known endemic regions. Biofilms produced by BP have been associated with antimicrobial therapy limitation and relapse melioidosis, thus making it urgently necessary to understand the mechanisms of biofilm formation and their role in BP biology. Microbial cells aggregate and enclose within a self-produced matrix of extracellular polymeric substances (EPSs) to form biofilm. The transition mechanism of bacterial cells from planktonic state to initiate biofilm formation, which involves the formation of surface attachment microcolonies and the maturation of the biofilm matrix, is a dynamic and complex process. Despite the emerging findings on the biofilm formation process, systemic knowledge on the molecular mechanisms of biofilm formation in BP remains fractured. This review provides insights into the signaling systems, matrix composition, and the biosynthesis regulation of EPSs (exopolysaccharide, eDNA and proteins) that facilitate the formation of biofilms in order to present an overview of our current knowledge and the questions that remain regarding BP biofilms.
    Matched MeSH terms: Bacterial Proteins/metabolism
  20. Jau MH, Yew SP, Toh PS, Chong AS, Chu WL, Phang SM, et al.
    Int J Biol Macromol, 2005 Aug;36(3):144-51.
    PMID: 16005060
    Three strains of Spirulina platensis isolated from different locations showed capability of synthesizing poly(3-hydroxybutyrate) [P(3HB)] under nitrogen-starved conditions with a maximum accumulation of up to 10 wt.% of the cell dry weight (CDW) under mixotrophic culture conditions. Intracellular degradation (mobilization) of P(3HB) granules by S. platensis was initiated by the restoration of nitrogen source. This mobilization process was affected by both illumination and culture pH. The mobilization of P(3HB) was better under illumination (80% degradation) than in dark conditions (40% degradation) over a period of 4 days. Alkaline conditions (pH 10-11) were optimal for both biosynthesis and mobilization of P(3HB) at which 90% of the accumulated P(3HB) was mobilized. Transmission electron microscopy (TEM) revealed that the mobilization of P(3HB) involved changes in granule quantity and morphology. The P(3HB) granules became irregular in shape and the boundary region was less defined. In contrast to bacteria, in S. platensis the intracellular mobilization of P(3HB) seems to be faster than the biosynthesis process. This is because in cyanobacteria chlorosis delays the P(3HB) accumulation process.
    Matched MeSH terms: Bacterial Proteins/metabolism*
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