Tektins (TEKTs) are constitutive filamentous proteins of microtubules in cilia, flagella, basal bodies, and centrioles. In mammals, five TEKTs (TEKT1, 2, 3, 4, and 5) have been identified in testis and spermatozoa. With the exception of TEKT1, these TEKTs have been reported to be present in spermatozoa with predominant localization at the peri-axoneme structures of flagella, i.e., mitochondria and outer dense fibers. In the present study, we produced an antibody against TEKT1 to examine the localization of TEKT1 in mouse, bull, and rat spermatozoa. By immunoblot analyses and immunofluorescence microscopy, we found TEKT1 to be present in sperm flagella and at the apical region of acrosome cap in spermatozoa of all these species. Acrosome-associated TEKT1 disappeared after in vitro acrosome reaction in mouse spermatozoa. These observations suggest another potential role for TEKT1 as a cytoskeletal element in the sperm head, or as a molecule involved in acrosome-related phenomena, such as acrosome reaction.

B (Tyrp1 ), the wild type allele at the mouse brown locus, produces black eumelanin, while b (Tyrp1^b), the recessive allele, produces brown eumelanin and exhibits lower tyrosinase (Tyr)-related protein 1 (Tyrp1) activity. However, it is unknown whether melanocyte proliferation and differentiation are affected by the Tyrp1^b mutation. The proliferation rate of brown (C57BL/10JHir (B10)-Tyrp1^b/ Tyrp1^b) melanocytes cultured in a serum-free melanocyte proliferation medium (MDMD) was similar to that of black (B10-Tyrp1 /Tyrp1 ) melanocytes. Although brown melanocytes exhibited normal morphology, their pigmentation was lower than that of black melanocytes. However, Tyr activity in brown melanocytes was increased both in vivo and in vitro. Melanosomes of cultured brown melanocytes were mostly spherical stage III melanosomes with granular depositions of pigments, whereas those of cultured black melanocytes were mostly stage IV ellipsoidal melanosomes with pigment depositions in intraluminal fibrils. Chemical analysis of melanin present in dorsal hairs of 5-week-old mice from the F₂ generation between brown and recessive yellow (B10-Mc1r^e/Mc1r^e) or agouti (B10-A/A) mice showed that eumelanin content was greatly decreased in brown and brown agouti (cinnamon) mice, whereas pheomelanin contents in brown recessive yellow and cinnamon mice did not differ from the corresponding Tyrp1 /- mice. These results suggest that the brown allele greatly inhibits eumelanin, but not pheomelanin synthesis.

We surveyed the genetic diversity and genetic differentiation of an endangered frog, Babina holsti, endemic to Okinawajima and Tokashikijima Islands of the Ryukyus, to elucidate its divergence history and obtain basic data for its conservation. Genetic differentiation between the two island lineages is moderate (3.1% p-distance in the cyt b gene). This result suggests that the two island lineages have been isolated between the late Pliocene and the middle Pleistocene and have never migrated between the current northern part of Okinawajima and Tokashikijima Islands, which were once connected in the late Pleistocene glacial age. On Okinawajima Island, the southernmost sample was constituted by a unique haplotype, without considerable genetic distance from haplotypes detected from northern samples. This unique haplotype composition in the southernmost sample would have resulted from the restricted gene flow between the southernmost population and the other populations in Okinawajima Island. Furthermore, the absence of genetic diversity within the southernmost sample indicates that this population has recently experienced population size reduction, possibly by predation pressure from an introduced mongoose, which is more abundant in the southern part than in the northern part of the island. Lower genetic diversity in the Tokashikijima sample implies a small effective population size for mitochondrial DNA (mtDNA) in B. holsti on the island. Immediate conservation measures should be taken for the populations from the southernmost range in Okinawajima and Tokashikijima.

We examined whether the ploidy level of eggs from sexual and parthenogenetic females of the weevil Scepticus insularis changes when field-collected, egg-bearing females are exposed to low temperature, as suggested by a previous study. We observed no change in ploidy level in eggs laid by sexual females (n = 15) treated by low temperature (1.1–6.7°C). In contrast, eggs laid by parthenogenetic females were not stable in ploidy level, as 11 of 16 females tested laid both diploid and triploid eggs even before the low-temperature treatment. After the low-temperature treatment, the proportion of triploid eggs to total eggs increased in nine individuals and decreased in the rest, and the effect of the treatment on the overall change in frequency was significant. Our results thus show that exposure to cold does not induce a change in egg ploidy in the sexual form of S. insularis, although cold may affect ploidy levels in the eggs of parthenogens. Additionally, eggs laid by laboratory-reared, virgin sexual females (n = 13) did not hatch after the low-temperature treatment, indicating that the treatment did not induce parthenogenetic reproduction in normally sexually reproducing females of S. insularis. We also examined the effect of low temperature on the ploidy level of eggs from parthenogenetic females (n = 4) of another weevil species, Catapionus gracilicornis, and confirmed that the proportion of triploid eggs steeply decreased and that of diploid eggs increased after exposure to cold, being consistent with those of previous studies.

Livestock grazing may negatively impact bird nesting in wetland habitats. This study evaluated the effect of grazing on the nests of the Oriental pratincole (Glareola maldivarum) along the grassland of a wetland at six study sites with different densities of grazing cattle and buffalo. Species richness, density, cover, and height of vegetation in the study areas were different (P < 0.05). The density of cattle and buffalo at the various sites affected vegetation composition and amount, which in turn influenced bird nest density. The estimated trampling rates, number of fledglings, and number of trampled eggs were different among study sites (P < 0.05). The density of cattle and buffalo has an influence on nest failure rates. The factors that influenced the mortality rates of the Oriental pratincole were trampling and unhatched eggs. Only 48.5% of the nests were successful at sites where cattle and buffalo continuously grazed in the grasslands at high densities. Thus, increases in the density of cattle and buffalo will reduce the number of nests of the Oriental pratincole, which may result in a reduction of the overall population in the future.

The present study elevates the number of cytogenetically analyzed ctenid species and genera from two to eight and six, respectively, presenting comparisons between chromosomal data obtained and the phylogenetic hypothesis proposed in the literature. Six ctenid species presented 13 autosomal pairs, exhibiting either X₁X₂O (Ctenus ornatus, Ctenus sp., Parabatinga brevipes and Phoneutria nigriventer) or X₁X₂X₃O sex chromosome systems (Nothroctenus sp. and Viracucha andicola). Asthenoctenus borellii showed 2n ♂ = 20 X₁X₂O. In all species, the chromosomes were telocentric. Some cells of one C. ornatus specimen exhibited one extra chromosome that, considering the behavioral similarities between the two chromosomes, can be considered to be supernumerary, derived from or giving rise to a sex chromosome. Silver impregnation revealed nucleolar organizer regions on one autosomal pair of C. ornatus and P. nigriventer (Cteninae) and two pairs of V. andicola (Acanthocteninae). Chromosomal data suggests that the X₁X₂X₃O system arose several times in the evolution of entelegyne spiders, and that conversion of an X₁X₂O system into an X₁X₂X₃O system and vice-versa has been a relatively common event in spiders. All the chromosomal data corroborate the close relationship between Ctenus and Phoneutria, the placement of P. brevipes within Cteninae, the placement of Anahita in a separated branch within Cteninae, and the inclusion of A. borellii in a distinct group within the ctenids (Viridasiinae), all of which are as proposed by phylogenetic hypotheses available in the literature.

We performed a molecular cytogenetic investigation of the scleractinian coral Acropora solitaryensis, which is dominant in the temperate region of Japan (30–35°N). Molecular cytogenetic analysis, using fluorescence in situ hybridization (FISH), was carried out for karyotyping and gene mapping. We propose the karyotype of this coral (2n = 30) based on C-banding and FISH analyses. FISH mapping of the rRNA gene was carried out with a probe generated by PCR amplification using rRNA gene primers. Furthermore, the telomeres and centromeres of all chromosomes were visualized using FISH. By comparative genomic hybridization using DNA from sperm and unfertilized eggs of this coral, we offer evidence suggesting the existence of sex chromosomes in this species. Collectively, these data advance our understanding of coral genetics.

Due to human activity and a reduction in the size and quality of wetland habitats, populations of the Eastern sarus crane (Grus antigone sharpii) have declined dramatically across their range in Southeast Asia. Conservation efforts in Thailand have focused on reintroduction of the founders harboring the highest genetic diversity. One of the most important requirements to ensure the persistence of the reintroduced populations is a balanced sex ratio. In this study we tested three simple PCR-based methods which may be used for reliable sex identification in G. a. sharpii. The first method employs two combined primer sets based on a 0.6 kb EcoRI fragment (EE0.6). The second method is based on the intronic length polymorphism of the chromo-helicase DNA binding protein (CHD). The last technique relies on PCR-RFLP technique. The sex of six known and 24 unknown cranes were successfully identified by all three methods. These PCR-based sex identification methods are also useful for captive breeding management of G. a. sharpii.