The Effects of GABA on embryonic gonadotropin-releasing hormone neurons in rat hypothalamic primary culture

Gonadotropin-releasing hormone (GnRH) neurons arise in the olfactory placode, migrate into the preoptic area (POA), and then extend axons to the median eminence during embryogenesis. Little information is available concerning the properties of GnRH neurons during the late gestational period when GnRH neurons reach the POA and form neuronal networks, although many studies have examined such properties during earlier developmental stages or the postnatal period. The present study was performed to elucidate the involvement of gamma-aminobutyric acid (GABA), one of the major neurotransmitters modifying GnRH neural activity, in regulation of GnRH gene expression on embryonic day 18.5 (E18.5) using transgenic rats expressing enhanced green fluorescence protein (EGFP) under the control of GnRH promoter. First, using RT-PCR, the mRNA of two isoforms of the GABA-synthesizing enzyme glutamic acid decarboxylase (GAD), GAD65 and GAD67 was detected in E18.5 embryonic POA-containing tissues. GAD67-positive cells were also demonstrated in close vicinity to GnRH-positive cells by immunohistochemistry, and immunoreactivity for both the GABA-A and GABA-B receptor subunits was detected in GnRH neurons. Next, primary cultures derived from anterior hypothalamic tissue of E18.5 embryos were prepared, and the effects of GABA and its agonists on GnRH promoter activity were evaluated using EGFP expression as a marker. GABA and the GABA-A receptor agonist muscimol, but not the GABA-B receptor agonist baclofen, significantly increased the EGFP-positive/GnRH-positive cell ratio. These results suggest that GABA plays a role in stimulating GnRH gene expression through GABA-A receptors in embryonic GnRH neurons in late gestational stages.     

Effects of heat stress on production,somatic cell score and conception rate in Holsteins

We examined the effects of heat stress (HS) on production traits, somatic cell score (SCS) and conception rate at first insemination (CR) in Holsteins in Japan. We used a total of 228 242 records of milk, fat and protein yields, and SCS for the first three lactations, as well as of CR in heifers and in first‐ and second‐lactation cows that had calved for the first time between 2000 and 2012. Records from 47 prefectural weather stations throughout Japan were used to calculate the temperature–humidity index (THI); areas were categorized into three regional groups: no HS (THI < 72), mild HS (72 ≤ THI < 79), and moderate HS (THI ≥ 79). Trait records from the three HS‐region groups were treated as three different traits and trivariate animal models were used. The genetic correlations between milk yields from different HS groups were very high (0.91 to 0.99). Summer calving caused the greatest increase in SCS, and in the first and second lactations this increase became greater as THI increased. In cows, CR was affected by the interaction between HS group and insemination month: with summer and early autumn insemination, there was a reduction in CR, and it was much larger in the mild‐ and moderate‐HS groups than in the no‐HS group.     

Porcine skeletal muscle troponin is a good source of peptides with Angiotensin-I converting enzyme inhibitory activity and antihypertensive effects in spontaneously hypertensive rats

In the search for novel peptides that inhibit the angiotensin I-converting enzyme (ACE), porcine skeletal troponin was hydrolyzed with pepsin, and the products were subjected to various types of chromatography to isolate active peptides. Glu-Lys-Glu-Arg-Glu-Arg-Gln (EKERERQ) and Lys-Arg-Gln-Lys-Tyr-Asp-Ile (KRQKYDI) were identified as active peptides, and their 50% inhibitory concentrations were found to be 552.5 and 26.2 microM, respectively. These are novel ACE inhibitory peptides, and the activity of KRQKYDI was the strongest among previously reported troponin-originated peptides. KRQKYDI was slowly hydrolyzed by treatment with ACE, and kinetic studies indicated that this peptide was a competitive inhibitor of the enzyme. When KRQKYDI was administered orally to spontaneously hypertensive rats (SHR) at a dose of 10 mg/kg, a temporary antihypertensive activity was observed at 3 and 6 h after administration.     

Distribution of immunoglobulin-positive cells in the spleen and kidney of Japanese flounder Paralichthys olivaceus

SUMMARY: The distribution of surface immunoglobulin-positive (sIg⁺) cells in the spleen, the head-kidney, and the trunk-kidney of adult Japanese flounder Paralichthys olivaceus was investigated by a flow cytometric analysis using a monoclonal antibody FB17 against flounder immunoglobulin M. Although the percentage of sIg⁺ cells varied among organs, a good correlation was revealed between the percentage in the head-kidney and that in the trunk-kidney ( r = 0.996, P < 0.001). In contrast, no correlation was obtained between the percentage of sIg⁺ cells in the spleen and the head-kidney or trunk-kidney. The head-kidney and the trunk-kidney contained cells bearing fewer sIg that were stained dimly by FB17 in addition to brightly stained sIg⁺ cells regarded as mature B cells, while the spleen contained only sIg⁺ cells stained brightly. Moreover, the immunocytochemical analyses showed that the head-kidney contains plasma cells with strongly stained cytoplasm in addition to B cells with stained cell surface, which suggests that the cells with fewer sIg detected by flow cytometric analysis are presumed to be at a stage during the processes of differentiation to plasma cells. These results suggest that there are some differences between the spleen and kidney in the role of the immune system and it is considered that differentiation of B cells to plasma cells occurs in the kidney.     

Natural growth of juveniles of the sea cucumber <Emphasis Type="Italic">Apostichopus japonicus</Emphasis>: studying juveniles in the intertidal habitat in Hirao Bay,eastern Yamaguchi Prefecture,Japan

In order to determine the population dynamics of juvenile Apostichopus japonicus, successive surveys were conducted in the stony intertidal zone of Hirao Bay, Seto Inland Sea. The juveniles of the green and black types of this species grew well from January to June. Before this high growing season, zero year old juveniles were too small to be readily detected by visual observations during field surveys. During the high water temperature season from August to November, juveniles over 1 year of age estivated underneath rocks. They awakened from their estivation in November, and it took another month before they could eat and discharge. The juveniles mainly migrated from the intertidal zone before they reached 3 years of age. In the present work, three patterns of juvenile growth were found. It is suggested that these differences in juvenile growth are mainly caused by differences in their start times for growth initiation when they are zero years old.     

Sorption and desorption studies of Cs and Sr in contaminated soil samples around Fukushima Daiichi Nuclear Power Plant

Journal of Soils and Sediments - Huge amounts of radiocesium, radiostrontium, and fission products were released into the atmosphere during the Fukushima Daiichi Nuclear Power Plant (FDNPP)...     

Differential scanning calorimetry and circular dichroism spectrometry of walleye pollack myosin and light meromyosin

The thermodynamic properties of myosin and its C-terminal fragment, light meromyosin (LMM), from walleye pollack, a typical cold-water fish efficiently utilized on an industrial scale, were analyzed by using differential scanning calorimetry (DSC) and circular dichroism (CD) spectrometry. Recombinant walleye pollack LMM expressed in Escherichia coli was also subjected to DSC and CD measurements for reference. The two proteins prepared from frozen surimi showed three endothermic peaks, the transition temperatures (T(m)) of which were quite similar, although overall DSC patterns differed considerably from one another. Their alpha-helical contents determined by CD were low compared to values reported before for other species. On the other hand, recombinant LMM gave four endothermic peaks at 27.4, 30.8, 36.5, and 43.4 degrees C in DSC and showed an alpha-helical content of approximately 80%. The peak at 27.4 degrees C could not be observed in walleye pollack LMM prepared from frozen surimi and thus was possibly attributed to its C terminus, because this extreme C-terminal region is supposedly truncated during preparation of LMM by tryptic digestion.     

水稻生物调理剂的开发及培育壮秧机理的研究

有机育苗生物调理剂由吉林省农业科学院水稻研究所研制。研究结果表明,有机育苗生物调理剂具有杀灭病原菌、抑制杂草发生、提高床土养分含量等功能。使用有机育苗生物调理剂育苗,植株健壮,干物重高,根系发达,抗病力和抗逆性强,省工省力,使用安全。     

Laboratory observations of habitat selection in aestivating and active adult sea cucumber <Emphasis Type="Italic">Apostichopus japonicus</Emphasis>

In order to verify which factors affect habitat selection for aestivating and in the active adult Apostichopus japonicus, animals were tested for their selection of attachment site in an experimental device (1-m pipes) in which the perceived environmental stimuli (light intensity, degree of contact with a hard surface, geotaxis) varied depending on the attachment site. During the aestivating season, the animals showed a strong selection for attachment sites during the daytime and nighttime; they also showed positive stereotaxis (thigmotaxis), negative phototaxis, and negative geotaxis. The results suggest that (1) habitats are not suitable for the aestivating adult A. japonicus unless these three environmental requirements are satisfied.     

Complete Lipooligosaccharide Structure from Pseudoalteromonas nigrifaciens Sq02-Rifr and Study of Its Immunomodulatory Activity

Lipopolysaccharides (LPS) are surface glycoconjugates embedded in the external leaflet of the outer membrane (OM) of the Gram-negative bacteria. They consist of three regions: lipid A, core oligosaccharide (OS), and O-specific polysaccharide or O-antigen. Lipid A is the glycolipid endotoxin domain that anchors the LPS molecule to the OM, and therefore, its chemical structure is crucial in the maintenance of membrane integrity in the Gram-negative bacteria. In this paper, we reported the characterization of the lipid A and OS structures from Pseudoalteromonas nigrifaciens Sq02-Rif^r, which is a psychrotrophic Gram-negative bacterium isolated from the intestine of Seriola quinqueradiata. The immunomodulatory activity of both LPS and lipid A was also examined.