Prey envenomation does not improve digestive performance in Taiwanese pit vipers (Trimeresurus gracilis and T. stejnegeri stejnegeri).

It has been a common belief that snake venom may help in the digestion of its prey, although direct examples and supporting evidence have not been sufficient. To address this, the present study examined whether preinjecting natural amounts of pit viper venom into experimental mice may accelerate their digestion by the snakes or gain energy benefit as compared to the control without the envenomation. Live adults of two Asian pit viper species Trimeresurus gracilis and T. stejnegeri stejnegeri, which inhabit the cold and warm environment respectively, were the subjects studied herein. A natural dose of 1.2 mg of each of the pit viper venom in phosphate-buffered saline (PBS) was injected into the mouse (about 10% of the snake mass) before it was being fed to the same species of vipers, while the pit vipers in control group were given mouse injected with sterile PBS. The snakes were kept at 14 degrees C or 24 degrees C, and parameters of gut passage time, costs of digestion, and/or digestive efficiency were measured. The results did not support the hypotheses that envenomation facilitates prey digestion. The venom in fact caused longer first defecation time and lower assimilation energy at 14 degrees C. Besides, the time to reach the oxygen consumption peak, and the first defecation time of T. s. stejnegeri were longer than that of T. gracilis.

Evolution and dispersal of three closely related macaque species, Macaca mulatta, M. cyclopis, and M. fuscata, in the eastern Asia.

Macaca mulatta, M. cyclopis and M. fuscata are three closely related species in the fascicularis species group. M. mulatta is wide-spread in Asia, while M. cyclopis and M. fuscata are restricted to Taiwan and Japan, respectively. Both M. cyclopis and M. fuscata are thought to be derived from ancient 'mulatta' populations in the eastern Asia. In this study, we analyzed sequences of mitochondrial DNA control region to provide genetic evidence for the evolution and dispersal scenario of the three species proposed by Fooden and Albrecht [Fooden, J., Albrecht, G.H. 1999. Tail-length evolution in fascicularis-group macaques (Cercopithecidae: Macaca). Int. J. Primatol. 20, 431-440]. Our results indicated that several localities in the southern China and Vietnam harbored multiple divergent mtDNA lineages that may not have evolved sympatrically. These divergent mtDNA lineages may have originated from different ancient northern populations that retreated into southern localities during glacial periods. However, the age of the southward retreat and the northward recolonization may be dated back to a more ancient past during late middle Pleistocene (0.12-0.18 mya) instead of during the LGM (0.018 mya). Times of gene divergence between M. mulatta and the two island species, estimated by mean nucleotide difference, suggest the ancestral populations colonized Taiwan and Japan around 0.38-0.44 mya. In addition, a more recent age of mulatta-cyclopis-fuscata population divergence (when ancient populations were isolated), estimated to be 0.17 mya by net nucleotide divergence, is suggested.

Molecular cloning and sequence analysis of a cDNA encoding pituitary thyroid stimulating hormone beta-subunit of the Chinese soft-shell turtle Pelodiscus sinensis and regulation of its gene expression.

A cDNA encoding thyroid stimulating hormone beta-subunit (TSHbeta) was cloned from pituitary of the Chinese soft-shell turtle, Pelodiscus sinensis, and its regulation of mRNA expression was investigated for the first time in reptile. The Chinese soft-shell turtle TSHbeta cDNA was cloned from pituitary RNA by reverse transcription and polymerase chain reaction (RT-PCR), and rapid amplification cDNA end (RACE) methods. The Chinese soft-shell turtle TSHbeta cDNA consists of 580-bp nucleotides, including 67-bp nucleotides of 5'-untranslated region (UTR), 402-bp of the open reading frame, and 97-bp of 3'-UTR followed by a 14 poly (A) trait. It encodes a precursor protein molecule of 133 amino acids with a putative signal peptide of 19 amino acids and a putative mature protein of 114 amino acids. The number and position of 12 cysteine residues, presumably forming six disulfide bonds, one putative asparagine-linked glycosylation site, and six proline residues that are found at positions for changing the backbone direction of the protein have been conserved in the turtle as in other vertebrate groups. The deduced amino acid sequence of the Chinese soft-shell turtle TSHbeta mature protein shares identities of 82-83% with birds, 71-72% with mammals, 49-57% with amphibians, and 44-61% with fish. The Chinese soft-shell turtle pituitaries were incubated in vitro with synthetic TRH (TSH-releasing hormone), thyroxine and triiodothyronine at doses of 10(-10) and 10(-8)M. TRH stimulated, while thyroid hormones suppressed, TSHbeta mRNA levels in dose-related manner. The sequences of cDNA and its deduced peptide of TSHbeta as well as the regulation of its mRNA level were reported for the first time in reptile.

Molecular cloning of the cDNA encoding follicle-stimulating hormone beta subunit of the Chinese soft-shell turtle Pelodiscus sinensis, and its gene expression.

Follicle-stimulating hormone (FSH) is a member of the pituitary glycoprotein hormone family. These hormones are composed of two dissimilar subunits, alpha and beta. Very little information is available regarding the nucleotide and amino acid sequence of FSHbeta in reptilian species. For better understanding of the phylogenetic diversity and evolution of FSH molecule, we have isolated and sequenced the complementary DNA (cDNA) encoding the Chinese soft-shell turtle (Pelodiscus sinensis, Family of Trionychidae) FSHbeta precursor molecule by reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA end (RACE) methods. The cloned Chinese soft-shell turtle FSHbeta cDNA consists of 602-bp nucleotides, including 34-bp nucleotides of the 5'-untranslated region (UTR), 396-bp of the open reading frame, and 3'-UTR of 206-bp nucleotides. It encodes a 131-amino acid precursor molecule of FSHbeta subunit with a signal peptide of 20 amino acids followed by a mature protein of 111 amino acids. Twelve cysteine residues, forming six disulfide bonds within beta-subunit and two putative asparagine-linked glycosylation sites, are also conserved in the Chinese soft-shell turtle FSHbeta subunit. The deduced amino acid sequence of the Chinese soft-shell turtle FSHbeta shares identities of 97% with Reeves's turtle (Family of Bataguridae), 83-89% with birds, 61-70% with mammals, 63-66% with amphibians and 40-58% with fish. By contrast, when comparing the FSHbeta with the beta-subunits of the Chinese soft-shell turtle luteinizing hormone and thyroid stimulating hormone, the homologies are as low as 38 and 39%, respectively. A phylogenetic tree including reptilian species of FSHbeta subunits, is presented for the first time. Out of various tissues examined, FSHbeta mRNA was only expressed in the pituitary gland and can be up-regulated by gonadotropin-releasing hormone in pituitary tissue culture as estimated by fluorescence real-time PCR analysis.