Sexual size dimorphism in anurans fails to obey Rensch's rule.

BACKGROUND: Sexual size dimorphism (SSD) is related to ecology, behaviour and life history of organisms. Rensch's rule states that SSD increases with overall body size in species where males are the larger sex, while decreasing with body size when females are larger. To test this rule, we analysed literature as well as own data on male and female body size in anurans (39 species and 17 genera). We also tested the hypothesis that SSD is largely a function of age difference between the sexes. RESULTS: Our data set encompassed 36 species with female-biased SSD, and three species with male-biased SSD. All considered species failed to support Rensch's rule, also when the analyses were phylogenetically corrected. However, SSD was significantly correlated with Sexual Age Difference (SAD) across species. We also found a significant correlation between SSD contrasts and SAD contrasts. CONCLUSIONS: Our study suggests that Rensch's rule does not accurately describe macroevolutionary patterns of SSD in anurans. That SAD can explain most of the variation in SSD among species when controlling for phylogenetic effects suggests that phylogeny is not responsible for the broad relationship between age and size across the sexes.

Characterization of the complete mitochondrial genome of Ectropis grisescens (Lepidoptera, Geometridae).

Ectropis grisescens (Lepidoptera, Geometridae) is one of the main leaf-eating pests in tea plantations in China. In this study, the complete mitochondrial genome of this species was sequenced and assembled. The total length of the mitochondrial genome of E. grisescens was 15,794 bp (GenBank accession No. MW337302). The base composition was 41.26% for A, 39.49% for T, 7.92% for G, and 11.33% for C. The circular mitogenome contained 13 protein-coding genes, 2 ribosomal RNA genes, and 22 transfer RNA genes. Phylogenetic analysis performed using 13 protein-coding genes of 15 species of Geometridae and an out-group Pieris melete (Lepidoptera, Pieridae) showed that E. grisescens is closely related to species of E. obliqua, and this is consistent with the morphological identification.

Role of AMPK in the expression of tight junction proteins in heat-treated porcine Sertoli cells.

Hyperthermia can cause dysfunction of the tight junctions (TJs) in testes. Adenosine 5'-monophosphate-activated protein kinase (AMPK) participates in the regulation of TJs in testis. However, whether AMPK regulates the expression of TJ proteins in the response of Sertoli cells to heat treatment remains unknown. We subjected Sertoli cells from 3-week-old piglets to heat treatment (43 °C, 30 min), which decreased cell viability, and increased the early apoptosis rate. These effects were reversible and the cells gradually recovered to normal viability at 48 h post-heat treatment. Expression of TJ proteins (claudin 11, JAMA, occludin, and ZO1) was detected in immature porcine Sertoli cells. The mRNA and protein levels of TJ proteins significantly decreased at 1 h after heat exposure, but recovered with increasing recovery time. Additionally, the expression of claudin 11 in the cytoplasm was also markedly decreased by heat treatment. AMPK phosphorylation, the cellular ATP level, and Ca2+/calmodulin-dependent protein kinase kinase B (CaMKKB) level, but not the liver kinase B1 (LKB1) level, were downregulated by heat treatment. More importantly, activation or overexpression of AMPK, which is a regulator of the assembly of TJs, partially rescued the heat treatment-induced downregulation of TJ proteins. By contrast, AMPK knockdown using small interfering RNA (siRNA) further decreased the expression levels of TJ proteins. In addition, claudin 11 was almost undetectable post heat treatment. Collectively, this study demonstrated that heat treatment could reversibly perturb the expression of TJ proteins in immature porcine Sertoli cells by inhibiting the AMPK signaling pathway.

Distribution patterns and variation analysis of simple sequence repeats in different genomic regions of bovid genomes.

As the first examination of distribution, guanine-cytosine (GC) pattern, and variation analysis of microsatellites (SSRs) in different genomic regions of six bovid species, SSRs displayed nonrandomly distribution in different regions. SSR abundances are much higher in the introns, transposable elements (TEs), and intergenic regions compared to the 3'-untranslated regions (3'UTRs), 5'UTRs and coding regions. Trinucleotide perfect SSRs (P-SSRs) were the most frequent in the coding regions, whereas, mononucleotide P-SSRs were the most in the introns, 3'UTRs, TEs, and intergenic regions. Trifold P-SSRs had more GC-contents in the 5'UTRs and coding regions than that in the introns, 3'UTRs, TEs, and intergenic regions, whereas mononucleotide P-SSRs had the least GC-contents in all genomic regions. The repeat copy numbers (RCN) of the same mono- to hexanucleotide P-SSRs showed significantly different distributions in different regions (P < 0.01). Except for the coding regions, mononucleotide P-SSRs had the most RCNs, followed by the pattern: di- > tri- > tetra- > penta- > hexanucleotide P-SSRs in the same regions. The analysis of coefficient of variability (CV) of SSRs showed that the CV variations of RCN of the same mono- to hexanucleotide SSRs were relative higher in the intronic and intergenic regions, followed by the CV variation of RCN in the TEs, and the relative lower was in the 5'UTRs, 3'UTRs, and coding regions. Wide SSR analysis of different genomic regions has helped to reveal biological significances of their distributions.

Nucleotide sequence of cDNA encoding the mitochondrial precursor protein of the ATPase inhibitor from the giant panda (Ailuropoda melanoleuca).

Mitochondrial ATP synthase (F1Fo-ATPase) is regulated by an intrinsic ATPase inhibitor protein. In the present study, using RT-PCR combined with in silico cloning, we isolated and sequenced the cDNA encoding the inhibitor protein of the giant panda (Ailuropoda melanoleuca). The deduced protein sequence showed that the protein is composed of 106 amino acids and the estimated molecular weight of the ATPIF(1) protein is 12.32 kDa with an isoelectric point (pI) of 10.17. Alignment analysis revealed that the deduced protein sequence shares 66%, 78.3%, 66%, 72.6%, 77.4%, and 78.3% homology with that of Mus musculus, Pan troglodytes, Rattus norvegicus, Bos taurus, Macaca mulatta, and Homo sapiens, respectively. Topology prediction showed that there are three protein kinase C phosphorylation sites, one amidation site, three N-myristoylation sites, one casein kinase II phosphorylation site, and one tyrosine kinase phosphorylation site in the ATPase inhibitor. In particular, amino acids in the region between 39 and 72, which is the minimum sequence showing ATPase inhibitory activity, were highly conserved in the protein.

[Sexual size dimorphism and female individual fecundity of Saurogobio dabryi in the lower reaches of the Jialing River, Southwest China.] / 嘉陵江下游蛇鮈的两性异形与雌性个体生殖力.

To investigate the sexual morphological differences and female individual fecundity of Saurogobio dabryi, the sexual size dimorphism, sex ratio and female individual fecundity of 76 individuals collected from the lower reaches of the Jialing River (Hechuan section) in breeding season were analyzed. The results showed that the sex ratio of S. dabryi in the downstream of Jialing River was 1:1 in the breeding season, and no significant difference in the body size between males and females. However, some local morphological traits (such as cephalosome and the truck) exhibited significant difference between males and females, for example, the head, the pectoral fin and the pelvic fin were significantly larger in males than in females, while the width, height and length of trunk exhibited the opposite results, all which were related to the sexual selection. A principal component analysis showed that the first three components accounted for 75.2% of variations in the morphological variables. However, all traits overlapped between males and females, thus they could not be separated by morphological characters. By establishing discrimination function, 92.1% samples could be distinguished. The individual fecundity of S. dabryi ranged from 979 to 19979 eggs, and exhibited significant positive relationship with body length and carcass mass. Compared with the historical data, the fecundities of S. dabryi increased significantly in the present study, which should be the active adaption of the species to the currently depleting population, as well as to the changing of water ecological environment.

[Community structure of phycophyta and evaluation of water quality in Sichuan section of Jialing River].

In order to understand the characteristics of the phycophyta community structure and water quality in Sichuan section of Jialing River, water samples were collected from 12 sites along the section in dry season (January) and rainy season (September), with the phycophyta species composition, Shannon diversity index (H'), Pielou evenness index (E), and Margalef richness index (d) analyzed. A total of 171 phycophyta species (including variety) were collected, belonging to 8 phyla, 42 families, and 95 genera, among which, Bacillariophyta, Chlorophyta, and Cyanophyta were the dominant groups. In dry season, the mean cell density of the phycophyta was 14.71 x 10(4) ind x L(-1), being the highest at sites JX (28.33.4 x 10(4) ind x L(-1)) and HYZ (25.40 x 10(4) ind x L(-1)), and diatom species had a higher richness than the others. In rainy season, the mean cell density was only 10.78 x 10(4) ind x L(-1), being the lowest (3.31 x 10(4) ind x L(-1)) at site QJ, and the species richness of chlorophyta and cyanobateria had somewhat increase. In the whole section, the mean d, H', and E of the phycophyta were 2.35, 1.60, and 0.31 in dry season, and 2.57, 2.09, and 0.39 in rainy season, respectively. Our results indicated that there were significant differences in the spatiotemporal distribution patterns of the community structure, cell density, diversity index, and evenness index of phycophyta in Sichuan section of Jialing River. The water quality of this section was overall belonged to mesosaprobic, being better at sites JX and SX (belonged to oligosaprobic or beta-mesosaprobic), but worse at sites CX, HYZ, XZ, and QJ (belonged to alpha-mesosaprobic).

A complete mitochondrial genome sequence of Asian black bear Sichuan subspecies (Ursus thibetanus mupinensis).

We obtained the complete mitochondrial genome of U.thibetanus mupinensis by DNA sequencing based on the PCR fragments of 18 primers we designed. The results indicate that the mtDNA is 16,868 bp in size, encodes 13 protein genes, 22 tRNA genes, and 2 rRNA genes, with an overall H-strand base composition of 31.2% A, 25.4% C, 15.5% G and 27.9% T. The sequence of the control region (CR) located between tRNA-Pro and tRNA-Phe is 1422 bp in size, consists of 8.43% of the whole genome, GC content is 51.9% and has a 6bp tandem repeat and two 10bp tandem repeats identified by using the Tandem Repeats Finder. U. thibetanus mupinensis mitochondrial genome shares high similarity with those of three other Ursidae: U. americanus (91.46%), U. arctos (89.25%) and U. maritimus (87.66%).