MyMedR

Transcriptional analysis of nitrogen fixation in Paenibacillus durus during growth in nitrogen-enriched medium

Halim MA, Choo QC, Ghazali AHA, Wajidi MFF, Najimudin N

Lett Appl Microbiol, 2021 May;72(5):610-618.

Paenibacillus durus strain ATCC 35681T is a Gram-positive diazotroph that displayed capability of fixing nitrogen even in the presence of nitrate or ammonium. However, the nitrogen fixation activity was detected only at day 1 of growth when cultured in liquid nitrogen-enriched medium. The transcripts of all the nifH homologues were present throughout the 9-day study. When grown in nitrogen-depleted medium, nitrogenase activities occurred from day 1 until day 6 and the nifH transcripts were also present during the course of the study albeit at different levels. In both studies, the absence of nitrogen fixation activity regardless of the presence of the nifH transcripts raised the possibility of a post-transcriptional or post-translational regulation of the system. A putative SigA box sequence was found upstream of the transcription start site of nifB1, the first gene in the major nitrogen fixation cluster. The upstream region of nifB2 showed a promoter recognizable by SigE, a sigma factor normally involved in sporulation.

Expression of a thermostable xylanase gene from Bacillus coagulans ST-6 in Lactococcus lactis

Raha AR, Chang LY, Sipat A, Yusoff K, Haryanti T

Lett Appl Microbiol, 2006 Mar;42(3):210-4.

PMID: 16478506

The aim of the study is to evaluate whether xylanase can be used as a potential reporter gene for cloning and expression studies in Lactococcus.

Growth of Bifidobacterium longum BB536 in medida (fermented cereal porridge) and their survival during refrigerated storage

Kabeir BM, Abd-Aziz S, Muhammad K, Shuhaimi M, Yazid AM

Lett Appl Microbiol, 2005;41(2):125-31.

PMID: 16033508

To develop medida, a Sudanese fermented thin porridge as a probiotic dietary adjunct with high total solids.

Rhodovulum sulfidophilum in the treatment and utilization of sardine processing wastewater

Azad SA, Vikineswary S, Chong VC, Ramachandran KB

Lett Appl Microbiol, 2004;38(1):13-8.

PMID: 14687209

Rhodovulum sulfidophilum was grown in settled undiluted and nonsterilized sardine processing wastewater (SPW). The aims were to evaluate the effects of inoculum size and media on the biomass production with simultaneous reduction of chemical oxygen demand (COD).

Optimization of carbon and nitrogen sources for phytase production by Mitsuokella jalaludinii, a new rumen bacterial species

Lan GQ, Abdullah N, Jalaludin S, Ho Y

Lett Appl Microbiol, 2002;35(2):157-61.

PMID: 12100593

The effects of different carbon and nitrogen sources on phytase production by Mitsuokella jalaludinii were evaluated and the optimization of rice bran (RB) and soybean milk (SM) concentrations in the medium for phytase production was also determined.

Growth and production of biomass of Rhodovulum sulfidophilum in sardine processing wastewater

Azad SA, Vikineswary S, Ramachandran KB, Chong VC

Lett Appl Microbiol, 2001 Oct;33(4):264-8.

PMID: 11559398

AIMS: Rhodovulum sulfidophilum was grown in sardine processing wastewater to assess growth characteristics for the production of bacterial biomass with simultaneous reduction of chemical oxygen demand.

METHODS AND RESULTS: Growth characteristics were compared in diluted and undiluted, settled and non-settled wastewater growing in anaerobic light and aerobic dark conditions; and also at different agitation speeds. The highest biomass (8.75 g l(-1)) and a reduction in chemical oxygen demand of 71% were obtained in unsettled, undiluted wastewater after 120 h culture with 15% inoculum. In settled wastewater, highest biomass (7.64 g l(-1)) and a COD reduction of 77% was also obtained after 120 h. Total biomass was higher (4.34 g l(-1)) after 120 h culture in anaerobic light compared to (3.23 g l(-1)) in aerobic dark growth.

CONCLUSIONS, SIGNIFICANCE AND IMPACT OF THE STUDY: Better performance, mean of total biomass (6.97 g l(-1) after 96 h), total carotenoids (4.24 mg g(-1) dry cell from 24 h) and soluble protein (431 microg ml(-1) after 96 h) were obtained from aerobic dark culture at 300 rev min(-1). The COD reduction, however, was lower (69%) after 96 h culture. Thus, the benefits in the production of bacterial biomass in non-sterilized sardine processing wastewater with the reduction of chemical oxygen demand could be achieved.

Purification and N-terminal amino acid sequence of fructose-6-phosphate phosphoketolase from Bifidobacterium longum BB536

Fandi KG, Ghazali HM, Yazid AM, Raha AR

Lett Appl Microbiol, 2001 Apr;32(4):235-9.

PMID: 11298932

AIMS: The key enzyme in the fructose-6-phosphate shunt in bifidobacteria, Fructose-6-phosphate phosphoketolase (F6PPK; E.C. 4.1.2.22.), was purified to electrophoretic homogeneity for the first time from Bifidobacterium longum (BB536).

METHODS AND RESULTS: A three-step procedure comprising acetone fractionation followed by fast protein liquid chromatography (FPLC) resulted in a 30-fold purification. The purified enzyme had a molecular mass of 300 +/- 5 kDa as determined by gel filtration. It is probably a tetramer containing two different subunits with molecular masses of 93 +/- 1 kDa and 59 +/- 0.5 kDa, as determined by SDS-PAGE.

CONCLUSION: The deduced N-terminal amino acid sequences of the two subunits revealed no significant similarity between them and other proteins when compared to the data bases of EMBL and SWISS-PROT, indicating that this could be the first report on N-terminal amino acid sequence of F6PPK.

SIGNIFICANCE AND IMPACT OF THE STUDY: The data from this study will be used to design oligonucleotide probe specific for bifidobacteria and to study the gene encoded F6PPK.

Antimicrobial susceptibility of bifidobacteria

Yazid AM, Ali AM, Shuhaimi M, Kalaivaani V, Rokiah MY, Reezal A

Lett Appl Microbiol, 2000 Jul;31(1):57-62.

PMID: 10886616

Eighteen Bifidobacterium strains were tested for their susceptibility to a range of antimicrobial agents. All the strains tested, including the reference culture Lactobacillus acidophilus CH2, were susceptible to several groups of antimicrobial agents, they were cephalosporin (cefamandole, cefazolin, cefaperazone, cefoxitin), polypeptide (bacitracin), macrolide (erythromycin), penicillin (amoxicillin), phenicol (chloramphenicol) and beta-lactam (imipenem). Fourteen strains were resistant to more than 10 antibiotics. The reference culture was resistant to only three antibiotics. The results showed that bifidobacteria are resistant to a wide range of antimicrobial agents.

Isolation and molecular characterization of vancomycin-resistant Enterococcus faecium in Malaysia

Son R, Nimita F, Rusul G, Nasreldin E, Samuel L, Nishibuchi M

Lett Appl Microbiol, 1999 Aug;29(2):118-22.

PMID: 10499300

Nineteen strains of vancomycin-resistant Enterococcus faecium isolated from 10 of 75 (13.3%) tenderloin beef samples were examined for resistance to selected antibiotics, presence of plasmids, and genetic diversity by random amplification of polymorphic DNA analysis. All strains showed multiple resistant to the antibiotics tested. Multiple antibiotic indexing of the vancomycin-resistant E. faecium strains showed that all (100%) originated from high risk contamination environments where antibiotics were often used. Plasmids ranging in size from 1.5 to 36 megadalton were detected in 15 of 19 (79%) strains. Thus, three plasmid profiles and eight antibiotypes were observed among the E. faecium strains. A high degree of polymorphism was obtained by combining the results of the two primers used; with the 19 E. faecium strains being differentiated into 19 RAPD-types. These preliminary results suggest that RAPD-PCR has application for epidemiologic studies and that resistance patterns and plasmid profiling could be used as an adjunct to RAPD for the typing of E. faecium in the study area.

Acid and bile tolerance of Lactobacillus isolated from chicken intestine

Jin LZ, Ho YW, Abdullah N, Jalaludin S

Lett Appl Microbiol, 1998 Sep;27(3):183-5.

PMID: 9750324

Twelve Lactobacillus strains isolated from chicken intestine were used to investigate acid and bile tolerance in vitro. Ten out of the 12 strains were slightly affected by 0.3% bile salts, showing a delay of growth (d) of 0.6-37.2 min compared with growth in control cultures. Two strains were not affected by the bile salts. Of the 12 strains, seven could be arbitrarily classified as resistant (d < 15 min) and five as tolerant (15 min < d < or = 40 min). Lactobacillus strains from the caecum showed better tolerance to acid than those from the ileum. Generally, the survival of the ileal strains was very low at pH 1.0 and 2.0, and moderate at pH 3.0. In contrast, caecal Lactobacillus strains could survive at pH 1.0 for up to 2 h of incubation; growth was moderate at pH 2.0 and good at pH 3.0 and 4.0.

Fulltext Transfer of Campylobacter jejuni from raw to cooked chicken via wood and plastic cutting boards

Tang JY, Nishibuchi M, Nakaguchi Y, Ghazali FM, Saleha AA, Son R

Lett Appl Microbiol, 2011 Jun;52(6):581-8.

PMID: 21375548 DOI: 10.1111/j.1472-765X.2011.03039.x

We quantified Campylobacter jejuni transferred from naturally contaminated raw chicken fillets and skins to similar cooked chicken parts via standard rubberwood (RW) and polyethylene cutting boards (PE).

Fulltext Surface display of respiratory syncytial virus glycoproteins in Lactococcus lactis NZ9000

Lim SH, Jahanshiri F, Rahim RA, Sekawi Z, Yusoff K

Lett Appl Microbiol, 2010 Dec;51(6):658-64.

PMID: 20973806 DOI: 10.1111/j.1472-765X.2010.02950.x

A system for displaying heterologous respiratory syncytial virus (RSV) glycoproteins on the surface of Lactococcus lactis NZ9000 was developed.

Fulltext Characterization of Kluyveromyces marxianus as a potential feed additive for ruminants

Nooraee SE, Alimon AR, Ho YW, Abdullah N

Lett Appl Microbiol, 2010 Jun 1;50(6):578-84.

PMID: 20406377 DOI: 10.1111/j.1472-765X.2010.02836.x

The aim of this study was to find suitable yeast isolates as potential microbial feed additives for ruminants.

Fulltext Effects of feeding and induction strategy on the production of BmR1 antigen in recombinant E. coli

Norsyahida A, Rahmah N, Ahmad RM

Lett Appl Microbiol, 2009 Nov;49(5):544-50.

PMID: 19832937 DOI: 10.1111/j.1472-765X.2009.02694.x

To investigate the effects of feeding and induction strategies on the production of BmR1 recombinant antigen.

Fulltext In vitro fermentation of broiler cecal content: the role of lactobacilli and pH value on the composition of microbiota and end products fermentation

Meimandipour A, Shuhaimi M, Hair-Bejo M, Azhar K, Kabeir BM, Rasti B, et al.

Lett Appl Microbiol, 2009 Oct;49(4):415-20.

PMID: 19725887 DOI: 10.1111/j.1472-765X.2009.02674.x

To assess the probiotic effects of Lactobacillus agilis JCM 1048 and L. salivarius ssp. salicinius JCM 1230 and the pH on the cecal microflora of chicken and metabolic end products.

Fulltext Characterization of multiple-antimicrobial-resistant Salmonella enterica Subsp. enterica isolated from indigenous vegetables and poultry in Malaysia

Yoke-Kqueen C, Learn-Han L, Noorzaleha AS, Son R, Sabrina S, Jiun-Horng S, et al.

Lett Appl Microbiol, 2008 Mar;46(3):318-24.

PMID: 18179445 DOI: 10.1111/j.1472-765X.2007.02311.x

The aims of this communication were to study characterization of serogroups among Salmonella isolates and the relationship of antimicrobial resistance to serogroups. Multiple antimicrobial resistance (MAR) was performed on 189 Salmonella enterica isolates associated with 38 different serovars that were recovered from poultry and four types of indigenous vegetables.

Safety evaluation of Bifidobacterium pseudocatenulatum G4 as assessed in BALB/c mice

Kabeir BM, Yazid AM, Stephenie W, Hakim MN, Anas OM, Shuhaimi M

Lett Appl Microbiol, 2008 Jan;46(1):32-7.

PMID: 17944838

To assess the safety of Bifidobacterium pseudocatenulatum G4 in BALB/c mice that involves examination of bacterial translocation, changes in the internal organs and histology of the intestinal lining.

Isolation and identification of biocellulose-producing bacterial strains from Malaysian acidic fruits

Voon WW, Rukayadi Y, Meor Hussin AS

Lett Appl Microbiol, 2016 May;62(5):428-33.

PMID: 27002476 DOI: 10.1111/lam.12568

Biocellulose (BC) is pure extracellular cellulose produced by several species of micro-organisms that has numerous applications in the food, biomedical and paper industries. However, the existing biocellulose-producing bacterial strain with high yield was limited. The aim of this study was to isolate and identify the potential biocellulose-producing bacterial isolates from Malaysian acidic fruits. One hundred and ninety-three bacterial isolates were obtained from 19 local acidic fruits collected in Malaysia and screened for their ability to produce BC. A total of 15 potential bacterial isolates were then cultured in standard Hestrin-Schramm (HS) medium statically at 30°C for 2 weeks to determine the BC production. The most potent bacterial isolates were identified using 16S rRNA gene sequence analysis, morphological and biochemical characteristics. Three new and potent biocellulose-producing bacterial strains were isolated from soursop fruit and identified as Stenotrophomonas maltophilia WAUPM42, Pantoea vagans WAUPM45 and Beijerinckia fluminensis WAUPM53. Stenotrophomonas maltophilia WAUPM42 was the most potent biocellulose-producing bacterial strain that produced the highest amount of BC 0·58 g l(-1) in standard HS medium. Whereas, the isolates P. vagans WAUPM45 and B. fluminensis WAUPM53 showed 0·50 and 0·52 g l(-1) of BC production, respectively.

Enhanced rhamnolipid production by Pseudomonas aeruginosa USM-AR2 via fed-batch cultivation based on maximum substrate uptake rate

Noh NA, Salleh SM, Yahya AR

Lett Appl Microbiol, 2014 Jun;58(6):617-23.

PMID: 24698293 DOI: 10.1111/lam.12236

A fed-batch strategy was established based on the maximum substrate uptake rate (MSUR) of Pseudomonas aeruginosa USM-AR2 grown in diesel to produce rhamnolipid. This strategy matches the substrate feed rates with the substrate demand based on the real-time measurements of dissolved oxygen (DO). The MSUR was estimated by determining the time required for consumption of a known amount of diesel. The MSUR trend paralleled the biomass profile of Ps. aeruginosa USM-AR2, where the MSUR increased throughout the exponential phase indicating active substrate utilization and then decreased when cells entered stationary phase. Rhamnolipid yield on diesel was enhanced from 0·047 (g/g) in batch to 0·110 (g/g) in pulse-pause fed-batch and 0·123 (g/g) in MSUR fed-batch. Rhamnolipid yield on biomass was also improved from 0·421 (g/g) in batch, 3·098 (g/g) in pulse-pause fed-batch to 3·471 (g/g) using MSUR-based strategy. Volumetric productivity increased from 0·029 g l(-1) h(-1) in batch, 0·054 g l(-1) h(-1) in pulse-pause fed-batch to 0·076 g l(-1) h(-1) in MSUR fed-batch.

Fulltext Effects of thermosonication on the fate of Escherichia coli O157:H7 and Salmonella Enteritidis in mango juice

Kiang WS, Bhat R, Rosma A, Cheng LH

Lett Appl Microbiol, 2013 Apr;56(4):251-7.

PMID: 23278854 DOI: 10.1111/lam.12042

In this study, the effects of thermosonication and thermal treatment on Escherichia coli O157:H7 and Salmonella Enteritidis in mango juice were investigated at 50 and 60°C. Besides, nonlethal injury of Salm. Enteritidis after both treatments was also examined. The highest inactivation was attained with thermosonication at 60°C. The inactivation rate was different for both pathogens, and Salm. Enteritidis was found to be more sensitive to thermosonication than E. coli O157:H7. Salmonella Enteritidis was recovered in all treated samples, except those subjected to more than 5-min thermosonication at 60°C. It was found that the introduction of high-intensity ultrasound enhanced the inactivation of pathogens compared to thermal treatment alone. On the other hand, Salm. Enteritidis was detected in a number of samples following incubation in universal pre-enrichment broth, but no growth was detected after incubation in mango juice.

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