A New PCR-Based Approach Indicates the Range of Clonorchis sinensis Now Extends to Central Thailand

Differentiation of the fish-borne trematodes belonging to the Opisthorchiidae, Heterophyidae and Lecithodendriidae is important from a clinical and epidemiological perspective, yet it is impossible to do using conventional coprological techniques, as the eggs are morphologically similar. Epidemiological investigation therefore currently relies on morphological examination of adult worms following expulsion chemotherapy. A PCR test capable of amplifying a segment of the internal transcribed spacer region of ribosomal DNA for the opisthorchiid and heterophyid flukes eggs taken directly from faeces was developed and evaluated in a rural community in central Thailand. The lowest quantity of DNA that could be amplified from individual adults of Opisthorchis viverrini, Clonorchis sinensis and Haplorchis taichui was estimated at 0.6 pg, 0.8 pg and 3 pg, respectively. The PCR was capable of detecting mixed infection with the aforementioned species of flukes under experimental conditions. A total of 11.6% of individuals in rural communities in Sanamchaikaet district, central Thailand, were positive for ‘Opisthorchis-like’ eggs in their faeces using conventional parasitological detection techniques. In comparison to microscopy, the PCR yielded a sensitivity and specificity of 71.0% and 76.7%, respectively. Analysis of the microscopy-positive PCR products revealed 64% and 23% of individuals to be infected with O. viverrini and C. sinensis, respectively. The remaining 13% (three individuals) were identified as eggs of Didymozoidae, presumably being passed mechanically in the faeces following the ingestion of infected fishes. An immediate finding of this study is the identification and first report of a C. sinensis–endemic community in central Thailand. This extends the known range of this liver fluke in Southeast Asia. The PCR developed herein provides an important tool for the specific identification of liver and intestinal fluke species for future epidemiological surveys.     

Potential of phenothiazine as a thin film dosimeter for UVA exposures.

The research reported in this paper on the changes in absorbance and the calibration of a proposed UVA (320-400 nm) dosimeter have established the phenothiazine-mylar combination as a potential UVA dosimeter for population studies of UVA exposures. The change in optical absorbance at 370 nm was employed to quantify the UVA exposures. This change starts to saturate at a change in absorbance of approximately 0.3. This relates to solar UVA exposures at a sub-tropical site on a horizontal plane of approximately three to four hours. The shape of this calibration curve varies with the season. This can be overcome in the same manner as for polysulfone where the dosimeter is calibrated for the conditions that it will be employed to measure the UVA exposures.     

pks+ Escherichia coli more prevalent in benign than malignant colorectal tumors

Molecular Biology Reports - Some E. coli strains that synthesize the toxin colibactin within the 54-kb pks island are being implicated in colorectal cancer (CRC) development. Here, the prevalence...     

Detection of a null allele for MDH isozymes in the guppy (Poecilia reticulata), with special reference to sex-linked inheritance

Malate dehydrogenase (MDH) was examined by starch gel electrophoresis for strain differences in the guppy, Poecilia reticulata. The electrophoretic patterns revealed duplicate gene loci encoding a mitochondrial form of MDH and the existence of a null allele at one of the duplicate loci. Different phenotypic frequencies at Mdh-4 were observed among 9 strains and between males and females within each strain. The progeny tests for Mdh-4 variants in the inter-strain crosses indicated a mode of partial sex-linked inheritance.     

Molecular phylogenetics of Caenogastropoda (Gastropoda: Mollusca)

Caenogastropoda is the dominant group of marine gastropods in terms of species numbers, diversity of habit and habitat and ecological importance. This paper reports the first comprehensive multi-gene phylogenetic study of the group. Data were collected from up to six genes comprising parts of 18S rRNA, 28S rRNA (five segments), 12S rRNA, cytochrome c oxidase subunit I, histone H3 and elongation factor 1alpha. The alignment has a combined length of 3995 base positions for 36 taxa, comprising 29 Caenogastropoda representing all of its major lineages and seven outgroups. Maximum parsimony, maximum likelihood and Bayesian analyses were conducted. The results generally support monophyly of Caenogastropoda and Hypsogastropoda (Caenogastropoda excepting Architaenioglossa, Cerithioidea and Campanilioidea). Within Hypsogastropoda, maximum likelihood and Bayesian analyses identified a near basal clade of nine or 10 families lacking an anterior inhalant siphon, and Cerithiopsidae s.l. (representing Triphoroidea), where the siphon is probably derived independently from other Hypsogastropoda. The asiphonate family Eatoniellidae was usually included in the clade but was removed in one Bayesian analysis. Of the two other studied families lacking a siphon, the limpet-shaped Calyptraeidae was associated with this group in some analyses, but the tent-shaped Xenophoridae was generally associated with the siphonate Strombidae. The other studied hypsogastropods with an anterior inhalant siphon include nine families, six of which are Neogastropoda, the only traditional caenogastropod group above the superfamily-level with strong morphological support. The hypotheses that Neogastropoda are monophyletic and that the group occupies a derived position within Hypsogastropoda are both contradicted, but weakly, by the molecular analyses. Despite the addition of large amounts of new molecular data, many caenogastropod lineages remain poorly resolved or unresolved in the present analyses, possibly due to a rapid radiation of the Hypsogastropoda following the Permian-Triassic extinction during the early Mesozoic.     

Species discrimination and population differentiation in ants using microsatellites

This study was conducted to establish the regional scale of population differentiation of ants in the wheat belt of central western New South Wales. Microsatellite variation was surveyed at five loci in two morphologically similar ant species (designated "A" and "B") from the Camponotus ephippium complex. Three of the five scored microsatellite loci were highly variable with totals, in the two species, of 11, 13 and 42 alleles. The other loci had two and three alleles. The mean number of alleles per locus per sample ranged from 2.0 to 4.6 for species A and from 1.4 to 3.8 in species B. Mean observed heterozygosity was 0.385 for species A and 0.363 for species B. The geographic distribution of genotypes was significantly non-random for all tested loci in both species. Eight of 47 alleles in species A and 15 of 28 in species B were restricted to a single site. Allelic accumulation percentages were calculated for several orderings of samples - level of heterozygosity, sample size and geographic position. In all orderings three or more samples must be included for more than three-quarters of alleles to be represented.