Morphological and genetic variations of the freshwater leech, Hirudinaria spp., in Peninsular Malaysia.

In this study the genetic diversity of local freshwater leeches (Hirudinaria spp.) was inferred using mtDNA COI gene analysis and compared with the gross external variations of 26 freshwater leech specimens obtained from the wild and leech farms. Based on a neighbor-joining tree generated from 516 COI base sequences, four distinct clades of Hirudinaria were seen with interspecific genetic divergence in the range of 7.6-14.5%. The external morphological variations based on the presence of stripes, location of gonopores, and anus separated the samples into four morphologically distinct groups matching the four clades obtained from the molecular data. Two black stripes at the ventral region were observed only in specimens found clustered with clades that contained the GenBank-reported H. manillensis, whereas the brown or dark green coloration without stripes on the ventral region was seen in samples that clustered with H. javanica and H. bpling clades.

Genetic diversity of Tomistoma schlegelii inferred from mtDNA markers.

The genetic diversity of the endangered crocodile Tomistoma schlegelii was characterized using the protein coding ND 6-tRNA(glu)-cyt b and the cytochrome b-control region (cyt b-CR) markers. Concatenate data revealed six haplotypes with an overall haplotype diversity of 0.769 ± 0.039; nucleotide diversity was 0.00535 ± 0.00172. A nearest-neighbor analysis showed that all individuals clustered with four geographic regions (Sumatra, Peninsular Malaysia, Sarawak, and East Kalimantan) and were genetically differentiated. With the exception of the individuals from haplotype H2, which occurred in both Peninsular Malaysia and Sarawak, all other haplotypes were geographically distinct. The H4 lineage, which was found to be the most divergent, clustered exclusively in the basal clade in all phylogenetic trees, and the haplotype network was unconnected at the 95% reconnection limit, suggesting further investigation to establish its possible status as a distinct evolutionary significant unit or a cryptic species.

Heteroplasmy, length, and sequence characterization of the mitochondrial control region in Tomistoma schlegelii.

This study describes the organization of the repetitive pattern in the mtDNA control region of Tomistoma schlegelii. Using newly designed primers, we detected length variations of approximately 50-100 bp among individuals, and only one individual showed a heteroplasmic band. Sequencing the region after CSB III revealed two main patterns: a repeat motif and a variable number tandem repeat (VNTR) pattern. The VNTR region, with a core unit of 104 bp, consisting of four motifs and a short AT chain, is implicated in the length variation seen among individuals of Tomistoma. A conserved motif seen in a family unit indicated that the repeat pattern was stably inherited from the maternal parent to all offspring. A combination of VNTR patterns specific to different crocodilians was seen in Tomistoma, and the overall secondary structure was shown to be similar to that in Crocodylus and Gavialis.

An evaluation of CHD-Specific primer sets for sex typing of birds from feathers.

The amplification of the highly conserved chromo-helicase-DNA binding region found in both the Z and W chromosome was evaluated with three sets of primers (P8/P2, 1237L/1272H and 2550F/2718R). DNA extracted from feathers through a simple boiling method was used to address its reliability in generating the sex-linked bands. All the bird samples, including the seven bird families that have not been reported previously, were successfully amplified with the primer set 2550F/2718R. The resulting polymerase chain reaction products showed clearly resolved fragments on a conventional agarose gel electrophoresis with size differences ranging from 80 to 540 bp between the two respective ZW gene copies. Although the P8/P2 primer was not as effective under the same conditions, it was able to produce well-resolved Z and W bands from bird species under the Antidea family, whereas the 2250F/2718R primer set only produced a single amplified fragment of a different size between the male and the female. Zoo Biol 27:62-69, 2008. (c) 2007 Wiley-Liss, Inc.

Susceptibility of Human Oral Squamous Cell Carcinoma (OSCC) H103 and H376 cell lines to Retroviral OSKM mediated reprogramming.

Although numbers of cancer cell lines have been shown to be successfully reprogrammed into induced pluripotent stem cells (iPSCs), reprogramming Oral Squamous Cell Carcinoma (OSCC) to pluripotency in relation to its cancer cell type and the expression pattern of pluripotent genes under later passage remain unexplored. In our study, we reprogrammed and characterised H103 and H376 oral squamous carcinoma cells using retroviral OSKM mediated method. Reprogrammed cells were characterized for their embryonic stem cells (ESCs) like morphology, pluripotent gene expression via quantitative real-time polymerase chain reaction (RT-qPCR), immunofluorescence staining, embryoid bodies (EB) formation and directed differentiation capacity. Reprogrammed H103 (Rep-H103) exhibited similar ESCs morphologies with flatten cells and clear borders on feeder layer. Reprogrammed H376 (Rep-H376) did not show ESCs morphologies but grow with a disorganized morphology. Critical pluripotency genes Oct4, Sox2 and Nanog were expressed higher in Rep-H103 against the parental counterpart from passage 5 to passage 10. As for Rep-H376, Nanog expression against its parental counterpart showed a significant decrease at passage 5 and although increased in passage 10, the level of expression was similar to the parental cells. Rep-H103 exhibited pluripotent signals (Oct4, Sox2, Nanog and Tra-1-60) and could form EB with the presence of three germ layers markers. Rep-H103 displayed differentiation capacity into adipocytes and osteocytes. The OSCC cell line H103 which was able to be reprogrammed into an iPSC like state showed high expression of Oct4, Sox2 and Nanog at late passage and may provide a potential iPSC model to study multi-stage oncogenesis in OSCC.

Induced pluripotent stem cells from human hair follicle keratinocytes as a potential source for in vitro hair follicle cloning.

BACKGROUND: Human hair follicles are important for the renewal of new hairs and their development. The generation of induced pluripotent stem cells (iPSCs) from hair follicles is easy due to its accessibility and availability. The pluripotent cells derived from hair follicles not only have a higher tendency to re-differentiate into hair follicles, but are also more suited for growth in hair scalp tissue microenvironment. METHODS: In this study, human hair follicular keratinocytes were used to generate iPSCs, which were then further differentiated in vitro into keratinocytes. The derived iPSCs were characterised by using immunofluorescence staining, flow cytometry, and reverse-transcription PCR to check for its pluripotency markers expression. RESULTS: The iPSC clones expressed pluripotency markers such as TRA-1-60, TRA-1-81, SSEA4, OCT4, SOX2, NANOG, LEFTY, and GABRB. The well-formed three germ layers were observed during differentiation using iPSCs derived from hair follicles. The successful formation of keratioctyes from iPSCs was confirmed by the expression of cytokeratin 14 marker. DISCUSSION: Hair follicles represent a valuable keratinocytes source for in vitro hair cloning for use in treating hair balding or grafting in burn patients. Our significant findings in this report proved that hair follicles could be used to produce pluripotent stem cells and suggested that the genetic and micro-environmental elements of hair follicles might trigger higher and more efficient hair follicles re-differentiation.