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Enhancement of thermostable lipase production by a genotypically identified extremophilic Bacillus subtilis NS 8 in a continuous bioreactor

Olusesan AT, Azura LK, Abubakar F, Mohamed AK, Radu S, Manap MY, et al.

J. Mol. Microbiol. Biotechnol., 2011 Apr;20(2):105-15.
PMID: 21422764 DOI: 10.1159/000324535

Bacillus strain NS 8, a lipase-producing bacterium isolated from a Malaysian hot spring, is able to tolerate a broad range of temperature and pH, which makes it beneficial for this study. It generated PCR products with molecular weight of 1,532 bp, and the 16S rRNA sequence analysis identified it as Bacillus subtilis with accession number AB110598. It showed a 71% similarity index with B. subtilis using Biolog Microstation System. Its lipase production was optimized using a shake flask system by changing the physical (agitation speed, pH and temperature) and nutritional (nitrogen, carbon and minerals) factors. The most suitable combination of the basal medium for lipase production was 2.5% olive oil (carbon), 1.5% peptone (nitrogen), 0.1% MgSO(4) (mineral) at an optimum temperature of 50°C, pH 7.5 and 150 rpm agitation, giving an enzyme yield of 4.23 U/ml. Statistical optimization using response surface methodology was carried out. An optimum lipase production of 5.67 U/ml was achieved when olive oil concentration of 3%, peptone 2%, MgSO(4)·7H(2)O 0.2% and an agitation rate of 200 rpm were combined. Lipase production was further carried out inside a 2-liter bioreactor, which yielded an enzyme activity of 14.5 U/ml after 15 h of incubation.

Matched MeSH terms: DNA, Ribosomal/genetics
Fulltext Myxosporean hyperparasites of gill monogeneans are basal to the multivalvulida

Freeman MA, Shinn AP

Parasit Vectors, 2011;4:220.
PMID: 22115202 DOI: 10.1186/1756-3305-4-220

Myxosporeans are known from aquatic annelids but parasitism of platyhelminths by myxosporeans has not been widely reported. Hyperparasitism of gill monogeneans by Myxidium giardi has been reported from the European eel and Myxidium-like hyperparasites have also been observed during studies of gill monogeneans from Malaysia and Japan.The present study aimed to collect new hyperparasite material from Malaysia for morphological and molecular descriptions. In addition, PCR screening of host fish was undertaken to determine whether they are also hosts for the myxosporean.

Matched MeSH terms: DNA, Ribosomal/genetics
Fulltext Assessment of the yeast species composition of cocoa bean fermentations in different cocoa-producing regions using denaturing gradient gel electrophoresis

Papalexandratou Z, De Vuyst L

FEMS Yeast Res., 2011 Nov;11(7):564-74.
PMID: 22093683 DOI: 10.1111/j.1567-1364.2011.00747.x

The yeast species composition of 12 cocoa bean fermentations carried out in Brazil, Ecuador, Ivory Coast and Malaysia was investigated culture-independently. Denaturing gradient gel electrophoresis of 26S rRNA gene fragments, obtained through polymerase chain reaction with universal eukaryotic primers, was carried out with two different commercial apparatus (the DCode and CBS systems). In general, this molecular method allowed a rapid monitoring of the yeast species prevailing during fermentation. Under similar and optimal denaturing gradient gel electrophoresis conditions, the CBS system allowed a better separated band pattern than the DCode system and an unambiguous detection of the prevailing species present in the fermentation samples. The most frequent yeast species were Hanseniaspora sp., followed by Pichia kudriavzevii and Saccharomyces cerevisiae, independent of the origin of the cocoa. This indicates a restricted yeast species composition of the cocoa bean fermentation process. Exceptionally, the Ivorian cocoa bean box fermentation samples showed a wider yeast species composition, with Hyphopichia burtonii and Meyerozyma caribbica among the main representatives. Yeasts were not detected in the samples when the temperature inside the fermenting cocoa pulp-bean mass reached values higher than 45 °C or under early acetic acid production conditions.

Matched MeSH terms: DNA, Ribosomal/genetics
Quorum sensing in Aeromonas species isolated from patients in Malaysia

Chan KG, Puthucheary SD, Chan XY, Yin WF, Wong CS, Too WS, et al.

Curr Microbiol, 2011 Jan;62(1):167-72.
PMID: 20544198 DOI: 10.1007/s00284-010-9689-z

Bacterial quorum sensing signal molecules called N-acylhomoserine lactone (AHL) controls the expression of virulence determinants in many Gram-negative bacteria. We determined AHL production in 22 Aeromonas strains isolated from various infected sites from patients (bile, blood, peritoneal fluid, pus, stool and urine). All isolates produced the two principal AHLs, N-butanoylhomoserine lactone (C4-HSL) and N-hexanoyl homoserine lactone (C6-HSL). Ten isolates also produced additional AHLs. This report is the first documentation of Aeromonas sobria producing C6-HSL and two additional AHLs with N-acyl side chain longer than C(6). Our data provides a better understanding of the mechanism(s) of this environmental bacterium emerging as a human pathogen.

Matched MeSH terms: DNA, Ribosomal/genetics
Fulltext Molecular identification and transmission studies of X-cell parasites from Atlantic cod Gadus morhua (Gadiformes: Gadidae) and the northern black flounder Pseudopleuronectes obscurus (Pleuronectiformes: Pleuronectidae)

Freeman MA, Eydal M, Yoshimizu M, Watanabe K, Shinn AP, Miura K, et al.

Parasit Vectors, 2011;4:15.
PMID: 21299903 DOI: 10.1186/1756-3305-4-15

Epidermal pseudotumours from Hippoglossoides dubius and Acanthogobius flavimanus in Japan and gill lesions in Limanda limanda from the UK have been shown to be caused by phylogenetically related protozoan parasites, known collectively as X-cells. However, the phylogenetic position of the X-cell group is not well supported within any of the existing protozoan phyla and they are currently thought to be members of the Alveolata.Ultrastructural features of X-cells in fish pseudotumours are somewhat limited and no typical environmental stages, such as spores or flagellated cells, have been observed. The life cycles for these parasites have not been demonstrated and it remains unknown how transmission to a new host occurs. In the present study, pseudobranchial pseudotumours from Atlantic cod, Gadus morhua, in Iceland and epidermal pseudotumours from the northern black flounder, Pseudopleuronectes obscurus, in Japan were used in experimental transmission studies to establish whether direct transmission of the parasite is achievable. In addition, X-cells from Atlantic cod were sequenced to confirm whether they are phylogenetically related to other X-cells and epidermal pseudotumours from the northern black flounder were analysed to establish whether the same parasite is responsible for infecting different flatfish species in Japan.

Matched MeSH terms: DNA, Ribosomal/genetics
Detection and molecular characterization of Giardia isolated from recreational lake water in Malaysia

Lim YA, Ramasame SD, Mahdy MA, Sulaiman WY, Smith HV

Parasitol Res, 2009 Dec;106(1):289-91.
PMID: 19705155 DOI: 10.1007/s00436-009-1602-y

Nine 50-l surface water samples from a Malaysian recreational lake were examined microscopically using an immunomagnetisable separation-immunofluorescent method. No Cryptosporidium oocysts were detected, but 77.8% of samples contained low numbers of Giardia cysts (range, 0.17-1.1 cysts/l), which were genetically characterised by SSU rRNA gene sequencing. Genotype analyses indicated the presence of Giardia duodenalis assemblage A suggesting potential risk to public health. The present study represents the first contribution to our knowledge of G. duodenalis assemblages in Malaysian recreational water.

Matched MeSH terms: DNA, Ribosomal/genetics
Giardia intestinalis genotypes: Risk factors and correlation with clinical symptoms

Mohammed Mahdy AK, Surin J, Wan KL, Mohd-Adnan A, Al-Mekhlafi MS, Lim YA

Acta Trop, 2009 Oct;112(1):67-70.
PMID: 19560431 DOI: 10.1016/j.actatropica.2009.06.012

This study was conducted to identify genotypes related risk factors of Giardia intestinalis in an Orang Asli (aboriginal) community in Pahang, Malaysia. Stool samples were collected from 321 individuals aged between 2 and 76 years old, of whom 160 were males and 161 were females. Faecal samples were processed with trichrome staining technique for the primary identification of G. intestinalis. Molecular identification was carried out by the amplification of a partial SSU rRNA gene using nested PCR. PCR products were purified and genotyped. 42 samples successfully amplified from the 76 positive faecal samples, only 1 was Assemblage A, the rest were Assemblage B. Risk analysis based on the detected genotypes of Giardia using univariate analysis and logistic regression identified three significant risk factors of giardiasis caused by assemblage B which included children =12 years (OR=13.56, 95% CI=1.79-102.64, p=0.012), females (OR=2.52, 95% CI=1.11-5.75, p=0.027) and eating fresh fruits (OR=7.78, 95% CI=1.01-60.00, p=0.049). Assemblage B infection was significantly correlated with clinical symptoms of giardiasis (OR=2.4, 95% CI=1.13-5.12, p=0.019). Females infected with Assemblage B were at higher risk of manifesting gastroenteritis signs and symptoms (OR=3.9, 95% CI=1.50-10.31, p=0.004). It has been concluded that giardiasis is still a public health problem in Orang Asli community and most commonly caused by assemblage B. The dynamic of transmission is most probably anthroponotic which is human to human either directly or indirectly through contaminated food. This route of transmission should be considered in the control strategy of the disease. Mass treatment together with health education could be the most practical intervention for reducing the infection. Those at high risk should receive more attention from public health authorities.

Matched MeSH terms: DNA, Ribosomal/genetics
New species of Cryptosporidium Tyzzer, 1907 (Apicomplexa) from amphibian host: morphology, biology and phylogeny

Jirků M, Valigurová A, Koudela B, Krízek J, Modrý D, Slapeta J

Folia Parasitol., 2008 Jun;55(2):81-94.
PMID: 18666410

Cryptosporidium fragile sp. n. (Apicomplexa) is described from black-spined toads, Duttaphrynus melanostictus (Schneider) (Amphibia, Anura, Bufonidae) from the Malay Peninsula. The parasitized animals were directly imported from Malaysia and harboured C. fragile at the time of arrival. Oocysts were subspherical to elliptical with irregular contour in optical section, measuring 6.2 (5.5-7.0) x 5.5 (5.0-6.5) microm. Oocyst wall was smooth and colourless in light microscopy. The endogenous development of C. fragile in the stomach of black-spined toad was analysed in detail using light and electron microscopy. Cryptosporidian developmental stages were confined to the surface of gastric epithelial cells. In transmission experiments, C. fragile has not been infective for one fish species, four amphibian species, one species of reptile and SCID mice. Full length small subunit rRNA gene sequence was obtained. Phylogenetic reconstruction revealed distinct status of C. fragile within the clade of species with gastric localisation including Cryptosporidium muris Tyzzer, 1907, Cryptosporidium serpentis Levine, 1980 and Cryptosporidium andersoni Lindsay, Upton, Owens, Morgan, Mead et Blagburn, 2000. Described characteristics differentiate C. fragile from the currently recognized Cryptosporidium species. Our experience with the description of C. fragile has led us to revise the recommended criteria for an introduction of a new Cryptosporidium species name. C. fragile is the first species described and named from an amphibian host. Its prevalence of 83% (15/18) in black-spined toads within the 3 months after importation calls for strict quarantine measures and import regulation for lower vertebrates.

Matched MeSH terms: DNA, Ribosomal/genetics
Application of rDNA-PCR amplification and DGGE fingerprinting for detection of microbial diversity in a Malaysian crude oil

Liew PW, Jong BC

J Microbiol Biotechnol, 2008 May;18(5):815-20.
PMID: 18633276

Two culture-independent methods, namely ribosomal DNA libraries and denaturing gradient gel electrophoresis (DGGE), were adopted to examine the microbial community of a Malaysian light crude oil. In this study, both 16S and 18S rDNAs were PCR-amplified from bulk DNA of crude oil samples, cloned, and sequenced. Analyses of restriction fragment length polymorphism (RFLP) and phylogenetics clustered the 16S and 18S rDNA sequences into seven and six groups, respectively. The ribosomal DNA sequences obtained showed sequence similarity between 90 to 100% to those available in the GenBank database. The closest relatives documented for the 16S rDNAs include member species of Thermoincola and Rhodopseudomonas, whereas the closest fungal relatives include Acremonium, Ceriporiopsis, Xeromyces, Lecythophora, and Candida. Others were affiliated to uncultured bacteria and uncultured ascomycete. The 16S rDNA library demonstrated predomination by a single uncultured bacterial type by >80% relative abundance. The predomination was confirmed by DGGE analysis.

Matched MeSH terms: DNA, Ribosomal/genetics*
Fulltext Distribution of Candida in the oral cavity and its differentiation based on the internally transcribed spacer (ITS) regions of rDNA

Zahir RA, Himratul-Aznita WH

Yeast, 2013 Jan;30(1):13-23.
PMID: 23208647 DOI: 10.1002/yea.2937

This study aimed to determine the distribution of Candida species in the oral cavity and differentiate the species based on PCR amplification, including HinfI and MspI digestion, in order to assess the effectiveness of using the rDNA region for species identification. Samples from saliva as well as palate, tongue and cheek mucosa surfaces were collected from 45 individuals, consisting of three groups: periodontal disease patients; denture-wearers; and the control group. The samples were serially diluted, spread on BHI and YPD agar plates and scored for colony-forming units (CFUs). Fifteen random candidal colonies were isolated and subjected to genomic DNA extraction, based on glass beads disruption. Four primers were used to amplify regions in the rDNA, and the ITSI-5.8S-ITSII PCR product was digested by HinfI and MspI restriction enzymes. The microbial loads on all sites of the denture-wearers were found to be significantly higher than control, while in the periodontal disease group only the microbial loads on the tongue were significantly higher than control. Meanwhile, there was no significant difference at other sites. The restriction fragment lengths of the clinical samples were compared to those of seven control species, allowing the differentiation of all seven species and the identification of 14 species from the clinical samples. The MspI restriction digest was not able to distinguish between C. albicans and C. dubliniensis, whereas the HinfI digest could not distinguish between C. tropicalis and C. parapsilosis. It was concluded that PCR-RFLP of the candidal rDNA region has potential for species identification. This study demonstrates the potential use of candidal rDNA as a means for identifying Candida species, based on genotype. The results also indicate the possibility of constructing genetic probes that target specific restriction fragments in the ITSI-5.8S-ITSII region, enabling swift and precise identification of Candida species.

Matched MeSH terms: DNA, Ribosomal/genetics
Fulltext Nucleospora cyclopteri n. sp., an intranuclear microsporidian infecting wild lumpfish, Cyclopterus lumpus L., in Icelandic waters

Freeman MA, Kasper JM, Kristmundsson Á

Parasit Vectors, 2013;6:49.
PMID: 23445616 DOI: 10.1186/1756-3305-6-49

Commercial fisheries of lumpfish Cyclopterus lumpus have been carried out in Iceland for centuries. Traditionally the most valuable part is the eggs which are harvested for use as a caviar substitute.Previously reported parasitic infections from lumpfish include an undescribed intranuclear microsporidian associated with abnormal kidneys and mortalities in captive lumpfish in Canada. During Icelandic lumpfish fisheries in spring 2011, extensive enlargements to the kidneys were observed in some fish during processing. The aim of this study was to identify the pathogen responsible for these abnormalities.

Matched MeSH terms: DNA, Ribosomal/genetics
Fulltext Simian malaria in wild macaques: first report from Hulu Selangor district, Selangor, Malaysia

Akter R, Vythilingam I, Khaw LT, Qvist R, Lim YA, Sitam FT, et al.

Malar J, 2015 Oct 05;14:386.
PMID: 26437652 DOI: 10.1186/s12936-015-0856-3

BACKGROUND: Malaria is a vector-borne parasitic disease which is prevalent in many developing countries. Recently, it has been found that Plasmodium knowlesi, a simian malaria parasite can be life-threatening to humans. Long-tailed macaques, which are widely distributed in Malaysia, are the natural hosts for simian malaria, including P. knowlesi. The aim of the present study was to determine the prevalence of simian malaria parasites in long-tailed macaques in the district of Hulu Selangor, Selangor, Malaysia.
METHODS: A total of 70 blood samples were collected from Macaca fascicularis dwelling in the forest of Hulu Selangor by the Department of Wildlife and National Parks Peninsular Malaysia, Kuala Lumpur, Malaysia. DNA was extracted using PureLink™ Genomic DNA Kits. Conventional and nested PCR were used to detect the genus and species of Plasmodium parasites respectively. In addition, phylogenetic analysis was carried out to confirm the species of Plasmodium parasites.
RESULTS: Thirty-five (50 %) of the 70 samples were positive for Plasmodium using genus-specific primers. These positive samples were then subjected to nested PCR targeting the 18S ribosomal RNA genes to detect all five simian malaria parasites: namely, P. knowlesi, Plasmodium inui, Plasmodium cynomolgi, Plasmodium fieldi, and Plasmodium coatneyi. All five species of simian malaria parasites were detected. Of these, P. inui was the predominant (65.7 %), followed by P. knowlesi (60 %), P. cynomolgi (51.4 %) P. coatneyi (45.7 %) and P. fieldi (2.9 %). A total of nine macaques had mono-infection with P. knowlesi (four), P. cynomolgi (two), P. coatneyi (two) and P. fieldi (one). Eleven of the macaques had dual infections while 12 had triple infections. Three macaques were infected with four species of Plasmodium. Molecular and phylogenetic analysis confirmed the five species of Plasmodium parasites.
CONCLUSION: This study has provided evidence to elucidate the presence of transmission of malaria parasites among the local macaques in Hulu Selangor. Since malaria is a zoonosis, it is important to determine the new control strategies for the control of malaria.

Matched MeSH terms: DNA, Ribosomal/genetics
Effect of dietary fiber on the methanogen community in the hindgut of Lantang gilts

Cao Z, Liang JB, Liao XD, Wright AD, Wu YB, Yu B

Animal, 2016 Oct;10(10):1666-76.
PMID: 27052363 DOI: 10.1017/S1751731116000525

The primary objective of this study was to investigate the effect of dietary fiber on methanogenic diversity and community composition in the hindgut of indigenous Chinese Lantang gilts to explain the unexpected findings reported earlier that Lantang gilts fed low-fiber diet (LFD) produced more methane than those fed high-fiber diet (HFD). In total, 12 Lantang gilts (58.7±0.37 kg) were randomly divided into two dietary groups (six replicates (pigs) per group) and fed either LFD (NDF=201.46 g/kg) or HFD (NDF=329.70 g/kg). Wheat bran was the main source of fiber for the LFD, whereas ground rice hull (mixture of rice hull and rice bran) was used for the HFD. Results showed that the methanogens in the hindgut of Lantang gilts belonged to four known species (Methanobrevibacter ruminantium, Methanobrevibacter wolinii, Methanosphaera stadtmanae and Methanobrevibacter smithii), with about 89% of the methanogens belonging to the genus Methanobrevibacter. The 16S ribosomal RNA (rRNA) gene copies of Methanobrevibacter were more than three times higher (P0.05) was observed in 16S rRNA gene copies of Fibrobacter succinogenes between the two dietary groups, and 18S rRNA gene copies of anaerobic fungi in gilts fed LFD were lower than (P<0.05) those fed HFD. To better explain the effect of different fiber source on the methanogen community, a follow-up in vitro fermentation using a factorial design comprised of two inocula (prepared from hindgut content of gilts fed two diets differing in their dietary fiber)×four substrates (LFD, HFD, wheat bran, ground rice hull) was conducted. Results of the in vitro fermentation confirmed that the predominant methanogens belonged to the genus of Methanobrevibacter, and about 23% methanogens was found to be distantly related (90%) to Thermogymnomonas acidicola. In vitro fermentation also seems to suggest that fiber source did change the methanogens community. Although the density of Methanobrevibacter species was positively correlated with CH4 production in both in vivo (P<0.01, r=0.737) and in vitro trials (P<0.05, r=0.854), which could partly explain the higher methane production from gilts fed LFD compared with those in the HFD group. Further investigation is needed to explain how the rice hull affected the methanogens and inhibited CH4 emission from gilts fed HFD.

Matched MeSH terms: DNA, Ribosomal/genetics
Characterization of the SF agent, an Ehrlichia sp. isolated from the fluke Stellantchasmus falcatus, by 16S rRNA base sequence, serological, and morphological analyses

Wen B, Rikihisa Y, Yamamoto S, Kawabata N, Fuerst PA

Int. J. Syst. Bacteriol., 1996 Jan;46(1):149-54.
PMID: 8573488

The organism designated the SF agent was originally isolated in Japan in 1962 from Stellantchasmus falcatus metacercaria parasitic on gray mullet fish. The SF agent resembles members of the genus Ehrlichia morphologically and exhibits weak antigenic cross-reactivity with Ehrlichia sennetsu. This organism causes mild clinical signs in dogs, but severe splenomegaly and lymphadenopathy in mice. This suggests that the SF agent may be similar to either Neorickettsia helminthoeca, an intracellular parasite of a fluke and the cause of salmon poisoning disease in dogs, or E. sennetsu, the causative agent of human sennetsu ehrlichiosis in Japan and Malaysia. In order to determine the phylogenetic relationship between the SF agent and other ehrlichial species, the 16S rRNA gene was amplified by the PCR and sequenced. The SF agent sequence was most closely related to the sequences of Ehrlichia risticii (level of sequence similarity, 99.1%), the causative agent of Potomac horse fever, and E. sennetsu (level of sequence similarity, 98.7%). The next most similar sequence was that of N. helminthoeca, but the level of sequence similarity was only 93.7%. E. sennetsu, E. risticii, the SF agent, and N. helminthoeca formed a distinct cluster that was separated from all other ehrlichial species. As determined by immunofluorescence labeling, antiserum against the SF agent cross-reacted strongly with E. sennetsu, E. risticii, and N. helminthoeca. When three genetically distinct ehrlichial isolates obtained from horses with Potomac horse fever were compared with the SF agent, we found that the SF agent was most closely related to Ohio isolate 081, followed by IllinoisT (T = type strain) and a Kentucky isolate. We observed strong antigenic cross-reactivities and similarities in Western blot (immunoblot) reaction profiles when we compared the SF agent, E. risticii, and E. sennetsu; however, weaker antigenic cross-reactivity was observed when the SF agent and N. helminthoeca were compared. Our results indicate that the SF agent is antigenically more closely related to E. risticii and E. sennetsu than to N. helminthoeca. The biological and antigenic characteristics and the 16S rRNA sequence data suggest that the SF agent is a new species that belongs to the genus Ehrlichia.

Matched MeSH terms: DNA, Ribosomal/genetics*
Bifidobacterium infantis M-63 improves mental health in victims with irritable bowel syndrome developed after a major flood disaster

Ma ZF, Yusof N, Hamid N, Lawenko RM, Mohammad WMZW, Liong MT, et al.

Benef Microbes, 2019 Mar 13;10(2):111-120.
PMID: 30525951 DOI: 10.3920/BM2018.0008

Individuals in a community who developed irritable bowel syndrome (IBS) after major floods have significant mental health impairment. We aimed to determine if Bifidobacterium infantis M-63 was effective in improving symptoms, psychology and quality of life measures in flood-affected individuals with IBS and if the improvement was mediated by gut microbiota changes. Design was non-randomised, open-label, controlled before-and-after. Of 53 participants, 20 with IBS were given B. infantis M-63 (1×109 cfu/sachet/day) for three months and 33 were controls. IBS symptom severity scale, hospital anxiety and depression scale, SF-36 Questionnaire, hydrogen breath testing for small intestinal bacterial overgrowth and stools for 16S rRNA metagenomic analysis were performed before and after intervention. 11 of 20 who were given probiotics (M-63) and 20 of 33 controls completed study as per-protocol. Mental well-being was improved with M-63 vs controls for full analysis (P=0.03) and per-protocol (P=0.01) populations. Within-group differences were observed for anxiety and bodily pain (both P=0.04) in the M-63 per-protocol population. Lower ratio of Firmicutes/Bacteroidetes was observed with M-63 vs controls (P=0.01) and the lower ratio was correlated with higher post-intervention mental score (P=0.04). B. infantis M-63 is probably effective in improving mental health of victims who developed IBS after floods and this is maybe due to restoration of microbial balance and the gut-brain axis. However, our conclusion must be interpreted within the context of limited sample size. The study was retrospectively registered on 12 October 2017 and the Trial Registration Number (TRN) was NCT03318614.

Matched MeSH terms: DNA, Ribosomal/genetics
Characterization of Cryptocaryon irritans, a parasite isolated from marine fishes in Taiwan

Yambot AV, Song YL, Sung HH

Dis Aquat Organ, 2003 Mar 31;54(2):147-56.
PMID: 12747640

The ciliated protozoan parasite Cryptocaryon irritans infecting marine fishes in Taiwan is described. Developmental characteristics and sequences of the ribosomal DNA regions such as part of 18 S, the entire first internal transcribed spacer, and part of 5.8 S of various Taiwan isolates of C. irritans were investigated. A total of 5 isolates was obtained from different fish-host species and localities, the majority from cultured fish species. C. irritans from Taiwan is able to shift its developmental characteristics, i.e. from non-adherent to adherent tomonts, from individualistic to aggregate-forming tomonts, from infection of the gills only to infection of the gills and body. Thus, it is not possible to classify strains of C. irritans on the basis of these parameters. Premature tomonts that developed from dead fishes were able to produce theronts that could infect fish host. Isolates from Pingtung and the USA had identical nucleotide sequences while an isolate from Malaysia was identical to an Israel isolate. Percentage variation among pairs of Taiwan isolates showed a higher degree of variation than isolate sequences listed in GenBank. Sequence analysis revealed highly aberrant isolates in Taiwan, and a phylogenetic tree distinguished a marine and a low-salinity variant. C. irritans from marine fishes in Taiwan, therefore, display some characteristics not previously reported. Since manipulation of salinity in brackishwater ponds and marine cage sites is not feasible, there is a need to develop new strategies for the control and prevention of cryptocaryoniasis.

Matched MeSH terms: DNA, Ribosomal/genetics
Fulltext Isolation and characterization of Acanthamoeba spp. from air-conditioners in Kuala Lumpur, Malaysia

Chan LL, Mak JW, Low YT, Koh TT, Ithoi I, Mohamed SM

Acta Trop, 2011 Jan;117(1):23-30.
PMID: 20858455 DOI: 10.1016/j.actatropica.2010.09.004

During a study on the quality of the indoor environment, Acanthamoeba spp. were detected in 20 out of 87 dust samples collected from air-conditioners installed in a four-story campus building located in Kuala Lumpur, Malaysia. Twenty-one cloned Acanthamoeba isolates designated as IMU1 to IMU21 were established from the positive primary cultures. Five species were identified from the 16 isolates according to the morphological criteria of Pussard and Pons; i.e. A. castellanii, A. culbertsoni, A. griffini, A. hatchetti and A. polyphaga. Species identities for the remaining five isolates (IMU4, IMU5, IMU15, IMU20 and IMU21), however, could not be determined morphologically. At genotypic characterization, these isolates were placed into T3 (IMU14); T5 (IMU16 and IMU17) and T4 (all the remaining isolates). To predict the potential pathogenicity of these Acanthamoeba isolates, thermo- and osmotolerance tests were employed; many isolates were predicted as potential human pathogens based on the outcome of these tests. This is the first time potentially pathogenic Acanthamoeba have been isolated from air-conditioners in Malaysia.

Matched MeSH terms: DNA, Ribosomal/genetics
Fulltext Isolation of Pediococcus acidilactici Kp10 with ability to secrete bacteriocin-like inhibitory substance from milk products for applications in food industry

Abbasiliasi S, Tan JS, Ibrahim TA, Ramanan RN, Vakhshiteh F, Mustafa S, et al.

BMC Microbiol, 2012;12:260.
PMID: 23153191 DOI: 10.1186/1471-2180-12-260

Lactic acid bacteria (LAB) can be isolated from traditional milk products. LAB that secrete substances that inhibit pathogenic bacteria and are resistant to acid, bile, and pepsin but not vancomycin may have potential in food applications.

Matched MeSH terms: DNA, Ribosomal/genetics
High resolution melting analysis for the differentiation of Mycobacterium species

Issa R, Abdul H, Hashim SH, Seradja VH, Shaili N', Hassan NAM

J Med Microbiol, 2014 Oct;63(Pt 10):1284-1287.
PMID: 25038139 DOI: 10.1099/jmm.0.072611-0

A quantitative real-time PCR (qPCR) followed by high resolution melting (HRM) analysis was developed for the differentiation of Mycobacterium species. Rapid differentiation of Mycobacterium species is necessary for the effective diagnosis and management of tuberculosis. In this study, the 16S rRNA gene was tested as the target since this has been identified as a suitable target for the identification of mycobacteria species. During the temperature gradient and primer optimization process, the melting peak (Tm) analysis was determined at a concentration of 50 ng DNA template and 0.3, 0.4 and 0.5 µM primer. The qPCR assay for the detection of other mycobacterial species was done at the Tm and primer concentration of 62 °C and 0.4 µM, respectively. The HRM analysis generated cluster patterns that were specific and sensitive to distinguished small sequence differences of the Mycobacterium species. This study suggests that the 16S rRNA-based real-time PCR followed by HRM analysis produced unique cluster patterns for species of Mycobacterium and could differentiate the closely related mycobacteria species.

Matched MeSH terms: DNA, Ribosomal/genetics
Fulltext Molecular epidemiology of Cryptosporidium in HIV/AIDS patients in Malaysia

Asma I, Sim BL, Brent RD, Johari S, Yvonne Lim AL

Trop Biomed, 2015 Jun;32(2):310-22.
PMID: 26691260 MyJurnal

Cryptosporidiosis is a particular concern in immunocompromised individuals where symptoms may be severe. The aim of this study was to examine the epidemiological and molecular characteristics of Cryptosporidium infections in HIV/AIDS patients in Malaysia in order to identify risk factors and facilitate control measures. A modified Ziehl-Neelsen acid fast staining method was used to test for the presence of Cryptosporidium oocysts in the stools of 346 HIV/AIDS patients in Malaysia. Standard coproscopical methods were used to identify infections with other protozoan or helminths parasites. To identify the species of Cryptosporidium, DNA was extracted and nested-PCR was used to amplify a portion of the SSU rRNA gene. A total of 43 (12.4%) HIV-infected patients were found to be infected with Cryptosporidium spp. Of the 43 Cryptosporidium-positive HIV patients, 10 (23.3%) also harboured other protozoa, and 15 (34.9%) had both protozoa and helminths. The highest rates of cryptosporidiosis were found in adult males of Malay background, intravenous drug users, and those with low CD4 T cell counts (i.e., < 200 cells/mm3). Most were asymptomatic and had concurrent opportunistic infections mainly with Mycobacterium tuberculosis. DNA sequence analysis of 32 Cryptosporidium isolates identified C. parvum (84.3%), C. hominis (6.3%), C. meleagridis (6.3%), and C. felis (3.1%). The results of the present study revealed a high prevalence of Cryptosporidium infection in hospitalized HIV/AIDS patients. The results also confirmed the potential significance of zoonotic transmission of C. parvum in HIV infected patients, as it was the predominant species found in this study. However, these patients were found to be susceptible to a wide range of Cryptosporidium species. Epidemiological and molecular characterization of Cryptosporidium isolates provides clinicians and researchers with further information regarding the origin of the infection, and may enhance treatment and control strategies.

Matched MeSH terms: DNA, Ribosomal/genetics

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