Cryopreservation of porcine embryos derived from in vitro-matured oocytes

This study describes a cryopreservation method for porcine in vitro-produced (IVP) embryos using as a model parthenogenetic embryos derived from in vitro-matured (IVM) oocytes. IVP embryos at the expanded blastocyst stage were cryopreserved by vitrification using the minimum volume cooling (MVC) method and exhibited an embryo survival rate of 41.2%. Survival was then significantly improved (83.3%, P < 0.05) by decreasing the amount of cytoplasmic lipid droplets (delipation) prior to vitrification. IVP embryos at the 4-cell stage also survived cryopreservation when vitrified after delipation (survival rate, 36.0%), whereas post-thaw survival of nondelipated embryos was quite low (9.7%). Furthermore, it was demonstrated that porcine IVP morulae can be cryopreserved by vitrification following delipation by a noninvasive method (survival rate, 82.5%). These results clearly confirm that porcine embryos derived from IVM oocytes can be effectively cryopreserved with high embryo survival using the MVC method in conjunction with delipation.     

Phylogeography of the Coastal Mosquito Aedes togoi across Climatic Zones: Testing an Anthropogenic Dispersal Hypothesis

The coastal mosquito Aedes togoi occurs more or less continuously from subarctic to subtropic zones along the coasts of the Japanese islands and the East Asian mainland. It occurs also in tropical Southeast Asia and the North American Pacific coast, and the populations there are thought to have been introduced from Japan by ship. To test this hypothesis, the genetic divergence among geographic populations of A. togoi was studied using one mitochondrial and three nuclear gene sequences. We detected 71 mitochondrial haplotypes forming four lineages, with high nucleotide diversity around temperate Japan and declining towards peripheral ranges. The major lineage (L1) comprised 57 haplotypes from temperate and subarctic zones in Japan and Southeast Asia including southern China and Taiwan. Two other lineages were found from subtropical islands (L3) and a subarctic area (L4) of Japan. The Canadian population showed one unique haplotype (L2) diverged from the other lineages. In the combined nuclear gene tree, individuals with mitochondrial L4 haplotypes diverged from those with the other mitochondrial haplotypes L1—L3; although individuals with L1—L3 haplotypes showed shallow divergences in the nuclear gene sequences, individuals from Southeast Asia and Canada each formed a monophyletic group. Overall, the genetic composition of the Southeast Asian populations was closely related to that of temperate Japanese populations, suggesting recent gene flow between these regions. The Canadian population might have originated from anthropogenic introduction from somewhere in Asia, but the possibility that it could have spread across the Beringian land bridge cannot be ruled out.     

A conserved α helix of Bcs1, a mitochondrial AAA chaperone,is required for the Respiratory Complex III maturation

Bcs1 is a transmembrane chaperone in the mitochondrial inner membrane, and is required for the mitochondrial Respiratory Chain Complex III assembly. It has been shown that the highly-conserved C-terminal region of Bcs1 including the AAA ATPase domain in the matrix side is essential for the chaperone function. Here we describe the importance of the N-terminal short segment located in the intermembrane space in the Bcs1 function. Among the N-terminal 44 amino acid residues of yeast Bcs1, the first 37 residues are dispensable whereas a hydrophobic amino acid in the residue 38 is essential for integration of Rieske Iron-sulfur Protein into the premature Complex III from the mitochondrial matrix. Substitution of the residue 38 by a hydrophilic amino acid residue affects conformation of Bcs1 and interactions with other proteins. The evolutionarily-conserved short α helix of Bcs1 in the intermembrane space is an essential element for the chaperone function.     

Physiological roles of SAPK/JNK signaling pathway

Stress-activated protein kinase/c-Jun NH(2)-terminal kinase (SAPK/JNK) is activated by many types of cellular stresses and extracellular signals. Recent studies, including the analysis with knockout mice, have led to progress towards understanding the physiological roles of SAPK/JNK activation in embryonic development in addition to immune responses. SAPK/JNK activation plays essential roles in organogenesis during mouse development by regulating cell survival, apoptosis, and proliferation. Two SAPK/JNK activators, SEK1 and MKK7, are required for fetal liver formation and full activation of SAPK/JNK, which responds to various stimuli in an all-or-none manner. This article focuses on physiological roles of SAPK/JNK activation in fetal liver formation and in apoptosis regulation.     

Substitution of S-(beta-aminoethyl)-cysteine for active-site lysine of thermostable aspartate aminotransferase

The active site lysyl residue (K239) of the thermostable aspartate aminotransferase [EC 2.6.1.1] was replaced by cysteinyl residue by means of site-directed mutagenesis. The K239C mutant enzyme obtained was catalytically inactive. The reaction of the cysteinyl residue of the K239C mutant enzyme with ethylenimine led to the formation of S-(beta-aminoethylcysteinyl (SAEC) residue. The K239SAEC mutant enzyme obtained showed about 25% of the activity of wild-type enzyme, and absorbed at 375 nm, which suggested the internal Schiff base formation.     

Stumpy limb--an embryonic lethal mutation in Japanese quail (Coturnix coturnix japonica).

An embryonic lethal mutant was found in Japanese quail and named "stumpy limb (SL)". All SL embryos died at pre-hatching stages, showing brachycephaly, a thickened neck, short upper and lower beaks, and short and thick extremities, while their body length was similar to that of the normal embryos. Observations on the skeleton revealed a globular skull, unusual curvature of the Processus palatinus maxillaris of the upper beak, and shortening and thickening of the appendicular bones. Some embryos showed a bending of the humerus, femur and/or tibiotarsus. Abnormality was more conspicuous in the leg bones than in the wing bones. No conspicuous differences were observed in the vertebrae between the SL and normal embryos. A genetic analysis suggested that the mutation is controlled by an autosomal recessive gene, for which the gene symbol sl was proposed.     

A retrospective study of the efficacy of ramelteon for insomnia: relevance of dose and timing of administration

Sleep and Biological Rhythms - The objective of the study was to investigate the efficacy of ramelteon for insomnia, particularly with circadian disturbance, focusing on the relevance of dose and...     

Predator size divergence depends on community context

Body size is a multi‐functional trait related to various fitness components, but the relative importance of different selection pressures is seldom resolved. In Carabus japonicus beetles, of which the larvae exclusively prey on earthworms, adult body size is related to the presence/absence of a larger congener and habitat temperature. In sympatry, C. japonicus consistently exhibits smaller body size which is effective for avoiding interspecific mating, but in allopatry, it shows size variation unrelated to temperature. Here, we show that this predator–size variation is attributed to prey–size variation, associated with high phylogenetic diversity in earthworm communities. In allopatry, the predator size was larger where larger prey occurred. Larger adult size may have been selected because larger females produce larger larvae, which can subdue larger prey. Thus, in the absence of a larger congener, variation in prey body size had a pronounced effect on geographic body size divergence in C. japonicus.     

Genetic dissection of susceptibility to radiation-induced apoptosis of thymocytes and mapping of Rapop1, a novel susceptibility gene

Genetic dissection of susceptibility to radiation-induced apoptosis of thymocytes was performed by counting dead cells in histologically processed thymuses after 0.5 Gy of whole-body X-irradiation, using recombinant congenic (CcS/Dem) strains derived from inbred mouse strains BALB/cHeA (susceptible) and STS/A (resistant). A high (8/20) number of strains with lower dead cell scores than BALB/cHeA among CcS/ Dem recombinant congenic strains (RCS), which contain 12.5% of STS/A genome in the genetic background of BALB/cHeA strain, indicates that the difference between BALB/cHeA and STS/A is caused by several genes and that susceptibility probably requires BALB/ cHeA alleles at more than one locus. Similar results were obtained with CXS/Hg recombinant inbred (CXS/ Hg) strains. Analysis of F₂ hybrids between BALB/ cHeA and CcS-7, one of the CcS/Dem strains that showed lower dead cell scores than BALB/cHeA, demonstrated that a novel gene (Rapop1, radiation-induced apoptosis 1) controlling susceptibility to radiation-induced apoptosis in the thymus is located in the proximal region of mouse chromosome 16.