Production of marmoset eggs and embryos from xenotransplanted ovary tissues.

The common marmoset (Callithrix jacchus) has attracted attention as a valuable primate model for the analysis of human diseases. Despite the potential for primate genetic modification, however, its widespread lab usage has been limited due to the requirement for a large number of eggs. To make up for traditional oocyte retrieval methods such as hormone administration and surgical techniques, we carried out an alternative approach by utilizing ovarian tissue from deceased marmosets that had been disposed of. This ovarian tissue contains oocytes and can be used as a valuable source of follicles and oocytes. In this approach, the ovarian tissue sections were transplanted under the renal capsules of immunodeficient mice first. Subsequent steps consist of development of follicles by hormone administrations, induction of oocyte maturation and fertilization, and culture of the embryo. This method was first established with rat ovaries, then applied to marmoset ovaries, ultimately resulting in the successful acquisition of the late-stage marmoset embryos. This approach has the potential to contribute to advancements in genetic modification research and disease modeling through the use of primate models, promoting biotechnology with non-human primates and the 3Rs principle in animal experimentation.

Mental construction of object symbols from meaningless elements by Japanese macaques (Macaca fuscata).

When writing an object's name, humans mentally construct its spelling. This capacity critically depends on use of the dual-structured linguistic system, in which meaningful words are represented by combinations of meaningless letters. Here we search for the evolutionary origin of this capacity in primates by designing dual-structured bigram symbol systems where different combinations of meaningless elements represent different objects. Initially, we trained Japanese macaques (Macaca fuscata) in an object-bigram symbolization task and in a visually-guided bigram construction task. Subsequently, we conducted a probe test using a symbolic bigram construction task. From the initial trial of the probe test, the Japanese macaques could sequentially choose the two elements of a bigram that was not actually seen but signified by a visually presented object. Moreover, the animals' spontaneous choice order bias, developed through the visually-guided bigram construction learning, was immediately generalized to the symbolic bigram construction test. Learning of dual-structured symbols by the macaques possibly indicates pre-linguistic adaptations for the ability of mentally constructing symbols in the common ancestors of humans and Old World monkeys.

Newly established low seizure susceptible and seizure-prone inbred strains of Mongolian gerbil.

Two inbred strains of the Mongolian gerbil with different phenotypes in seizure behaviour and coat color were newly established. LSAG/Nu has low seizure susceptibility and albino phenotypes, whereas SPBG/Nu has seizure-prone and black coat color phenotypes. LSAG was compared with SPBG as to seizure incidence and grade. Mean ages at seizure onset of LSAG and SPBG were 6 and 3 months, respectively. Seizure incidences in over 9 months old LSAG and SPBG gerbils were 37.3% (66/177) and 95.2% (118/124), respectively. LSAG has a significantly lower incidence (p < 0.001) and grade (p < 0.001) of seizures than SPBG. Only a few seizing LSAG gerbils exhibited myoclonus to tonic-clonic seizure progression. These results suggest that LSAG has some mechanisms which delay the onset of seizures and prevent them from becoming serious. Both strains of gerbils can be expected to be useful animal models for the study of human idiopathic generalized epilepsy.

The Wnt/planar cell polarity pathway component Vangl2 induces synapse formation through direct control of N-cadherin.

Although regulators of the Wnt/planar cell polarity (PCP) pathway are widely expressed in vertebrate nervous systems, their roles at synapses are unknown. Here, we show that Vangl2 is a postsynaptic factor crucial for synaptogenesis and that it coprecipitates with N-cadherin and PSD-95 from synapse-rich brain extracts. Vangl2 directly binds N-cadherin and enhances its internalization in a Rab5-dependent manner. This physical and functional interaction is suppressed by ß-catenin, which binds the same intracellular region of N-cadherin as Vangl2. In hippocampal neurons expressing reduced Vangl2 levels, dendritic spine formation as well as synaptic marker clustering is significantly impaired. Furthermore, Prickle2, another postsynaptic PCP component, inhibits the N-cadherin-Vangl2 interaction and is required for normal spine formation. These results demonstrate direct control of classic cadherin by PCP factors; this control may play a central role in the precise formation and maturation of cell-cell adhesions at the synapse.

Effects of desalted deep seawater on hematologic and blood chemical values in mice.

Various processed foods and beverages have been manufactured using deep seawater (DSW), desalted DSW (dDSW), and concentrated DSW in Japan. To confirm the safety of dDSW, we investigated hematologic and blood chemical effects of dDSW in mice. The dDSW and desalted surface seawater (dSSW) were diluted to 6.7%, 10%, and 20% with purified water. BALB/c mice were housed for 12 weeks, and administered the diluted dDSW, dSSW, or purified water as a control during the period. The results for dDSW were compared with those for dSSW and purified water. None of the groups of mice showed any clear abnormal growth or behavior; neither did any show signs of illness nor a single case of death during the 12 weeks study. We found no significant differences between the dDSW and control groups in terms of red blood cell count, hemoglobin, hematocrit, white blood cell count, and neutrophil counts, whereas white blood cell and lymphocyte counts were significantly higher in the 10% dSSW group at the end of 4 and 12 weeks than those in the control group. A significantly higher triglyceride level was detected only in the 6.7% dSSW group. Our results show no evidence of acute or subacute effects of diluted dDSW. Effects of diluted dDSW on hematologic and blood chemical values in mice are thought to be similar to those of purified water. This finding suggests that dDSW is as safe as purified water for drinking water.