Recognition sites for nine different restriction endonucleases were mapped on rDNA genes of fasciolid species. Southern blots of digested DNA from individual worms were probed sequentially with three different probes derived from rDNA of Schistosoma mansoni and known to span between them the entire rDNA repeat unit in that species. Eighteen recognition sites were mapped for Fasciola hepatica, and seventeen for Fasciola gigantica and Fascioloides magna. Each fasciolid species had no more than two unique recognition sites, the remainder being common to one or both of the other two species. No intraspecific variation in restriction sites was noted in F. hepatica (individuals from 11 samples studied; hosts were sheep, cattle and laboratory animals; geographical origins. Australia, New Zealand, Mexico, U.K., Hungary and Spain), or in F. gigantica (two samples; Indonesia and Malaysia). Only one sample of F. magna was available. One specimen of Fasciola sp. from Japan (specific identity regarded in the literature as uncertain) yielded a restriction map identical to that of F. gigantica. Almost all recognition sites occurred in or near the putative rRNA coding regions. The non-transcribed spacer region had few or no cut sites despite the fact that this region is up to about one half of the entire repeat unit in length. Length heterogeneity was noted in the non-transcribed spacer, even within individual worms.
Fusarium species section Liseola namely F. fujikuroi, F. proliferatum, F. andiyazi, F. verticillioides, and F. sacchari are well-known plant pathogens on rice, sugarcane and maize. In the present study, restriction analysis of the intergenic spacer regions (IGS) was used to characterize the five Fusarium species isolated from rice, sugarcane and maize collected from various locations in Peninsular Malaysia. From the analysis, and based on restriction patterns generated by the six restriction enzymes, Bsu151, BsuRI, EcoRI, Hin6I, HinfI, and MspI, 53 haplotypes were recorded among 74 isolates. HinfI showed the most variable restriction patterns (with 11 patterns), while EcoRI showed only three patterns. Although a high level of variation was observed, it was possible to characterize closely related species and isolates from different species. UPGMA cluster analysis showed that the isolates of Fusarium from the same species were grouped together regardless of the hosts. We conclude that restriction analysis of the IGS regions can be used to characterize Fusarium species section Liseola and to discriminate closely related species as well as to clarify their taxonomic position.
Restriction endonuclease analyses (REAs) constitute the only inexpensive molecular approach capable of typing and characterizing human adenovirus (HAdV) strains based on the entire genome. However, the application of this method is limited by the need for time-consuming and labor-intensive procedures. We herein developed a simple and cost-effective REA for assessing HAdV. The method consists of (1) simple and cost-effective DNA extraction, (2) fast restriction endonuclease (RE) digestion, and (3) speedy mini agarose gel electrophoresis. In this study, DNA was isolated according to the kit-based method and 21.0 to 28.0 μg of viral DNA was extracted from prototypes (HAdV-1, HAdV-3, HAdV-4, and HAdV-37) in each flask. The amount of DNA ranged from 11.4 to 57.0 μg among the HAdV-3 (n=73) isolates. The obtained viral DNA was found to be applicable to more than 10 types of REAs. Fast-cut restriction endonucleases (REs) were able to digest the DNA within 15 minutes, and restriction fragments were easily separated via horizontal mini agarose gel electrophoresis. The whole procedure for 10 samples can be completed within approximately six hours (the conventional method requires at least two days). These results show that our REA is potentially applicable in many laboratories in which HAdVs are isolated.
Genetic variation among Malaysian isolates of Salmonella typhi was determined by analysis of ribosomal RNA gene restriction patterns. Of the 20 isolates analyzed, eight different pattern combinations were detected. The amount of variation observed was also dependent upon the restriction endonuclease used; PstI produced more different patterns than did SmaI. The results suggested that disease activity was due to a number of different clones circulating simultaneously rather than a single strain. Further implications of the data are discussed.
Specific human papillomavirus (HPV) types have been implicated in the development of cervical carcinoma worldwide. Novel molecular techniques have facilitated the detection and typing of HPV in cervical lesions. DNA preparations from a series of 23 histopathologically confirmed cervical carcinoma patients were analyzed by polymerase chain reaction (PCR) using degenerate primers for the presence of HPV DNA sequences. A total of 22 of 23 cases studied (95.7%) were found positive for HPV DNA sequences. Further studies by DNA hybridization with viral specific probe and restriction enzyme analysis demonstrated the presence of HPV 16 in 73.9% (17/23) and HPV 18 in 65.2% (15/23) of the cases examined. Interestingly, the uncommon HPV 31 and 33 were also found but with a lower percentage (16.9%). It was noted that HPV 16 frequency in the carcinoma increased with age but HPV 18 was evenly present at all ages investigated. We found that HPV was frequently associated with the majority of the cervical carcinomas, and in all but one case, oncogenic high risk HPV genotypes were present. We conclude that HPV infection of the genital tract has an important role in the development of the disease in Malaysia.
A study was initiated to amplify by polymerase chain reaction (PCR), a short factor VIII gene fragment containing the Bcl I restriction site from hemophilia patients using published primer sequences. Preliminary findings indicated that the resulting fragment is 142 bp long. This fragment, when digested with Bcl I restriction enzyme produced two fragments, 99 bp and 43 bp in length. Polymorphism in the Bcl I region can be used to detect carrier state in the family members of the hemophiliacs.
Salmonella enterica serovar Enteritidis infection is a common concern in poultry production for its negative effects on growth as well as food safety for humans. Identification of molecular markers that are linked to resistance to Salmonella Enteritidis may lead to appropriate solutions to control Salmonella infection in chickens. This study investigated the association of candidate genes with resistance to Salmonella Enteritidis in young chickens. Two native breeds of Malaysian chickens, namely, Village Chickens and Red Junglefowl, were evaluated for bacterial colonization after Salmonella Enteritidis inoculation. Seven candidate genes were selected on the basis of their physiological role in immune response, as determined by prior studies in other genetic lines: natural resistance-associated protein 1 (NRAMP1), transforming growth factor β3 (TGFβ3), transforming growth factor β4 (TGFβ4), inhibitor of apoptosis protein 1 (IAP1), caspase 1 (CASP1), lipopolysaccharide-induced tumor necrosis factor (TNF) α factor (LITAF), and TNF-related apoptosis-inducing ligand (TRAIL). Polymerase chain reaction-RFLP was used to identify polymorphisms in the candidate genes; all genes exhibited polymorphisms in at least one breed. The NRAMP1-SacI polymorphism correlated with the differences in Salmonella Enteritidis load in the cecum (P = 0.002) and spleen (P = 0.01) of Village Chickens. Polymorphisms in the restriction sites of TGFβ3-BsrI, TGFβ4-MboII, and TRAIL-StyI were associated with Salmonella Enteritidis burden in the cecum, spleen, and liver of Village Chickens and Red Junglefowl (P < 0.05). These results indicate that the NRAMP1, TGFβ3, TGFβ4, and TRAIL genes are potential candidates for use in selection programs for increasing genetic resistance against Salmonella Enteritidis in native Malaysian chickens.
The blue swimming crab (Portunus pelagicus) is a valuable marine fishery resource in Indo-West Pacific Ocean. So far, rare genetic resource of this species is available. In this report, the restriction-site associated DNA (RAD) approach was employed to mine the genomic information and identify molecular markers in P. pelagicus. A total of 0.82 Gbp clean data were generated from the genome of individual "X2A". De novo assembly produced 85,796 contigs with an average length of 339 bp. A total of 45,464 putative SNPs and 17,983 microsatellite loci were identified from the genomes of ten individuals. Furthermore, 31 pairs of primers were successfully designed, with 16 of them exhibiting polymorphism in a wild population. For these polymorphic loci, the expected and observed alleles per locus ranged from 1.064 to 7.314 and from 2 to 11, respectively. The expected and observed heterozygosity per locus ranged from 0.0615 to 0.819 and from 0.0626 to 1.000, respectively. Nine loci showed high informative with polymorphism information content (PIC) > 0.5. Five loci significantly deviated from Hardy-Weinberg equilibrium in the samples analyzed. No linkage disequilibrium was found among the 16 polymorphic microsatellite loci. This study provided massive genetic resource and polymorphic molecular markers that should be helpful for studies on conservation genetics, population dynamics and genetic diversity of P. pelagicus and related crab species.
Many species of Trichoderma have attracted interest as agents for the biological control of soil borne fungal pathogens of a range of crop plants. Research on the biochemical mechanisms associated with this application has focused on the ability of these fungi to produce enzymes which lyse fungal cell walls, and antifungal antibiotics. An important group of the latter are the non-ribosomal peptides called peptaibols. In this study Trichoderma asperellum, a strain used in biological control in Malaysia, was found to produce the peptaibol, trichotoxin. This type of peptide molecule is synthesised by a peptide synthetase (PES) enzyme template encoded by a peptide synthetase (pes) gene. Using nucleotide sequences amplified from adenylation (A-) domains as probes, to hybridise against a lambda FIXII genomic library from T. asperellum, 25 clones were recovered. These were subsequently identified as representative of four groups based on their encoding properties for specific amino acid incorporation modules in a PES. This was based on analysis of their amino acid sequences which showed up to 86% identity to other PESs including TEX 1.
An erythromycin resistance plasmid, pAJ01 was isolated from Loctococcus lactis isolate C5 that was isolated from a healthy two-week-old chicken cecum. A 4 kb plasmid was transformed into plasmidless L. lactis MG1363 before a restriction endonuclease map was constructed. It was then fused with pUC19 to form pAJ02, which can replicate in Escherichia coli XLI-Blue as well as L. lactis MG1363. The plasmid was stably maintained in Lactococcus for more than 100 generations.
Forty-nine isolates of Burkholderia pseudomallei from sporadic cases of melioidosis in Malaysia over the past 18 years were examined by BamHI ribotyping and pulsed-field gel electrophoresis (PFGE) of XbaI digests of total deoxyribonucleic acid (DNA). Twenty-four patients had septicaemic melioidosis with a mortality of 70%; mortality in the non-septicaemic disease was 16%. Five ribotype patterns were identified, 2 of which accounted for 90% of all isolates. PFGE revealed a number of different strains within these ribotypes, but some pairs of isolates from unrelated cases gave closely similar DNA profiles. These results are in agreement with Australian studies which showed a high prevalence of a few ribotypes of B. pseudomallei which are further divisible by genotyping, in areas where melioidosis is endemic.
We performed genome size estimation of 17 recent human isolates of Salmonella typhi from geographically diverse regions using pulsed-field gel electrophoresis (PFGE) after digestion of chromosomal DNA with restriction endonucleases XbaI (5'-TCTAGA-3'), AvrII (5'-CCTAGG-3') and SpeI (5'-ACTAGT-3'), and summation of the sizes of restriction fragments obtained. All 17 isolates had circular chromosomes, and genome sizes differed by as much as 959 kb, ranging from 3,964 to 4,923 kb (mean genome size = 4,528 kb). The data obtained confirm the usefulness of PFGE in studies of bacterial genome size and are in agreement with recent results indicating considerable genetic diversity and genomic plasticity of S. typhi. The variation in genome sizes noted may be relevant to the observed biological properties of this important human pathogen, including its virulence.
A total of 67 serovar reference strains and 7 isolates belonging to the genus Leptospira were characterized by ribosomal ribonucleic acid (rRNA) gene restriction patterns. Fifty patterns were observed. Strains belonging to different genomic species always gave different patterns. However, genomic species were subdivided into several patterns. Forty-three serovars gave a specific pattern. Some serovars could not be separated by rRNA gene restriction patterns: strains of serovars icterohaemorrhagiae, copenhageni, lai, pyrogenes and jalna gave pattern 1; serovars birkini, mankarso and wolffi gave pattern 4; serovars canicola, gem, hebdomadis, pomona and hardjo (strain hardjoprajitno) gave pattern 12; serovars valbuzzi and zanoni gave pattern 14; serovars jonsis, malaya and sumneri gave pattern 16; serovars arborea, ballum, castellonis and kenya gave pattern 35; and serovars borincana and shermani gave pattern 43. These data provide the bases for a molecular typing system for the genus Leptospira.
The constancy of strain genotypes of multiple isolates of Burkholderia pseudomallei from 13 patients with melioidosis was examined by BamHI ribotyping and pulsed-field gel electrophoresis (PFGE) of XbaI digests of DNA. Seven of 8 patients with single episodes of melioidosis each yielded genetically identical isolates and only one of five patients with recurrent episodes was infected with a new strain clearly distinct from the original primary strain. Variation was observed in PFGE patterns of primary and relapse isolates of another patient but this was insufficient to define genetically distinct strains. We conclude that most patients with single or multiple episodes of melioidosis retain a single strain.
Identification of Bactrocera carambolae Drew and Hancock, B. papayae Drew and Hancock, B. tau Walker, B. latifrons Hendel, B. cucurbitae Coquillett, B. umbrosa Fabricius and B. caudata Fabricius would pose a problem if only a body part or an immature stage were available. Analysis of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of cytochrome oxidase I (COI) gene using primers COIR, COIF, UEA7 and UEA10 and restriction enzymes (MseI, RsaI and Alu1) was carried out. The banding profiles in the electrophoresis gel were analysed.
Forty-six Malaysian patients with chronic granulocytic leukaemia were found to be rearranged in the breakpoint cluster region (BCR) of chromosome 22, molecular evidence of Philadelphia chromosome (t9.22) translocation. Through the use of a 1.2 kb 3' BCR probe and two restriction enzyme digests, patients' breakpoints could be localized either to 5' or 3' regions of the BCR. Breakpoint site localization at the time of DNA sampling did not show any positive statistical association to clinical status defined as chronic phase, chronic phase with less than 6 months to blast crisis, accelerated phase and blast crisis. This was in contrast to earlier reports which indicated that patients with breakpoint at 3' site were at a higher biologic risk for entering blast crisis.
The increased frequency of antibiotic resistance is known to be associated with the dissemination of integrons in the Enterobacteriaceae. This study determined the prevalence and type of integrons amongst 160 extended-spectrum beta-lactamase producing enterobacterial isolates kept in our culture collection. Integrons were detected in 98(61.3%) isolates, including 28(62.2%) Escherichia coli, 34(64.2%) Klebsiella spp., 27(61.4%), Enterobacter spp. and 9(50.0%) Citrobacter spp. investigated in this study. Restriction analysis of the integron gene fragments revealed that class I integron was the principal integron detected in 92(57.5%) of our isolates. Class II integron was detected in 6(3.8%) of our isolates, while no class III integron was detected in this study. The high rates of integron prevalence particularly of the class I integron in the E. coli and Klebsiella spp. concur with previous studies in other geographical regions. The higher (≥50%) integron prevalence of Citrobacter and Enterobacter isolates comparing to previous studies suggests the potential of these isolates as sources for dissemination of resistance determinants. The finding in this study serves as a basis for further study on the antibiotic resistance mechanisms of enterobacterial species in this teaching hospital.
Alpha-globin genes in crab-eating macaques were found to be triplicated at high frequencies according to restriction-enzyme comparisons. The frequencies of triplicated alpha-globin genes in macaques originally from Malaysia and Indonesia were 0.432 and 0.275, respectively, while no triplication was found in individuals from either the Philippines or northern and central Thailand. Quadruplicated alpha-globin genes were also observed, at frequencies of 0.045 (Malaysia), 0.075 (Indonesia), and 0.021 (the Philippines). A single locus was detected in only one of 40 chromosomes from Indonesia (frequency 0.025).
Legislation concerning the safety assessment and labelling of foodstuffs has been implemented in many countries. Consequential to a number of cases of food adulteration reported globally, a fast and reliable detection method for the food traceability is required in ensuring effective implementation of food legislation in a country. In this study, PCR-RFLP technique based on cyt b gene has been tested for its suitability for these purposes. This method combines the use of a pair of universal primer that amplifies a 359 bp fragment on the cyt b gene from meat muscle DNA and restriction enzyme analysis. Analysis of experimental beef frankfurter, minced beef, pork frankfurter and pork cocktail samples demonstrated the suitability of the assay for the detection of the beef (Bos taurus) and pork (Sus scrofa), but not applicable for some processed food, particularly detection of mackerel (Rasterelliger brachysoma), sardine (Saedinella Fimbriata) and tuna (Thunnus tonggol) origin in canned food. Commercial frauds through species mislabelling or misdescribed were not detected. The assay is demonstrated applicable for routine analysis of meat traceability of foodstuffs and legislation purposes, if sufficient availability of detectable mtDNA in the foodstuffs is ensured.