Afferent and efferent connections of the nucleus geniculatus lateralis ventralis demonstrated by WGA-HRP in the chick

Fibre connections of the chick nucleus geniculatus lateralis ventralis (GLv) were investigated using the axonal tracing method with wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP). After an injection of WGA-HRP into the GLv, many labelled neurons were observed in layer i of the stratum griseum et fibrosum superficiale (SGFS) in the ipsilateral tectum opticum (TO) and in the nucleus lentiformis mesencephali (LM). In the TO-GLv projection, cells of origin were located in the deeper part of layer i of the TO and were topographically distributed along the direction from the rostrodorsal part to the caudoventral part of the TO relating to a rostrocaudal axis of the GLv. In the LM-GLv connection, the dorsal and ventral parts of the LM connected reciprocally with the rostral and caudal halves of the GLv, respectively. In contrast, in the GLv efferent connection, labelled axon terminals spread widely in the ipsilateral area pretectalis without any clear topographical arrangement.     

稻瘟病菌致病性遗传研究初报——云南省稻瘟病菌有性世代研究之五

 本文报道龙爪稷分离菌G10-1马水稻分离菌后代菌性2145-R-57-1交配产生的同一子囊中分离出的子囊孢子致病性及交配型分离情况.交配型分离比1:1;但致病性分离情况比较复杂.很多子囊孢子菌株失去亲本菌株对供试水稻和龙爪稷的致病性,少数菌株获得亲本菌株所没有的致病性.对稻瘟病菌致病性的遗传尚需作大量分析工作.     

Evidence for autoregulation of cystathionine gamma-synthase mRNA stability in Arabidopsis

Control of messenger RNA (mRNA) stability serves as an important mechanism for regulating gene expression. Analysis of Arabidopsis mutants that overaccumulate soluble methionine (Met) revealed that the gene for cystathionine gamma-synthase (CGS), the key enzyme in Met biosynthesis, is regulated at the level of mRNA stability. Transfection experiments with wild-type and mutant forms of the CGS gene suggest that an amino acid sequence encoded by the first exon of CGS acts in cis to destabilize its own mRNA in a process that is activated by Met or one of its metabolites.     

Duration of egg formation in hens selected for increased rate of lay under 23 h and 24 h light-dark cycles

1. The intervals from oviposition to the next ovulation and the times spent by the ovum in various parts of the oviduct were examined, in hens selected for increased rate of lay over 5 generations under a 23 h light-dark cycle (23HS line) and kept in a 22 h light-dark cycle, and in hens selected under a 24 h light-dark cycle (24HS line) and kept in a 24 h light-dark environment. 2. The intervals from oviposition to the next ovulation were 13 min and 25 min in the 23HS and 24HS lines respectively. Times from ovulation to entry of the ovum into the uterus were 4 h 44 min and 4 h 43 min in the 23HS and 24HS lines respectively, and times spent by the ovum in the uterus were 19 h and 19 h 24 min in the 23HS and 24HS lines respectively. 3. It is concluded that the reduced oviposition interval in the 23HS line compared to the 24HS line was caused by the reduction in the interval from oviposition to the next ovulation and the time spent by the ovum in the uterus.     

Mos and the mitogen-activated protein kinase do not show cytostatic factor activity in early mouse embryos

Mos and the mitogen-activated protein kinase (MAPK) cascade have been established as crucial regulators of second meiotic metaphase arrest, the so-called CSF arrest, in mammalian oocytes. They are also thought to play a role in regulating mitotic metaphase arrest of early mammalian embryos. In the present study, we examined whether mitotic arrest is induced in early mouse embryos by activation of extracellular signal-regulated kinases (ERKs), which are major MAPKs in mouse eggs, and their substrate, p90Ribosomal S6 kinase (RSK), as reported in Xenopus embryos. Wild-type Mos (wt-Mos), degradation-resistant Mos mutant (P2G-Mos) or constitutive active mutant of MAPK/ERK kinase, MEK (SDSE-MEK), was expressed in early mouse embryos by injecting the respective expression vectors into the pronucleus of fertilized eggs, and the developmental rates were then examined up to 72 h after insemination. Expression of P2G-Mos and SDSE-MEK succeeded in activating ERKs and RSK in developing mouse embryos, while wt-Mos failed to activate them in spite of expression of mos mRNA, indicating that the wt-Mos protein is unstable in early mouse embryos. Although the activated levels of ERKs and RSK in the vector-injected embryos were comparable to those of meiotically arrested mouse oocytes, their developmental rates were identical to those of the control embryos. These results suggest that activation of MAPK and RSK does not induce mitotic arrest in early mouse embryos. The present study indicates that there are large physiological differences between early mouse embryos and mouse oocytes and that CSF arrest of mouse eggs in mitosis should be discussed separately from that in meiosis.     

Dose response to vaginal administration of 1,25-dihydroxyvitamin D3 to cows

It was previously reported that intravaginal (IVAG) administration of 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) might be protective against bovine hypocalcaemia. In the present study, various doses of exogenous 1,25(OH)(2)D(3) were administered IVAG to ovariectomised cows, and the subsequent changes in the biochemical parameters of the blood were measured to assess the characteristics of vaginal absorption. Five cows received 1,25(OH)(2)D(3) IVAG at a dose of 0.125, 0.25, 0.5, or 1.0microg/kg of body weight (BW) or intravenously at a dose of 1.0microg/kg BW. Dosing was at intervals of at least two weeks in a 5x5 Latin square design. Vaginally administered 1,25(OH)(2)D(3) was absorbed in a dose-dependent manner. There was no correlation between the IVAG dose of 1,25(OH)(2)D(3) and subsequent changes in plasma calcium concentrations. The bioavailability of 1,25(OH)(2)D(3) administered IVAG at 1.0microg/kg BW was approximately 93%.     

Effect of soft X-ray irradiation on the migratory ability of primordial germ cells in chickens

1. The present study was conducted to elucidate the effect of soft X-ray irradiation on the migratory ability of primordial germ cells (PGCs) to the germinal ridges of chicken embryos. 2. PGCs (Barred Plymouth Rock, BPR) were isolated from embryonic blood and irradiated with soft X-rays for 1-10 min. Then, the PGCs were transfected in vitro with GFP gene by lipofection. The manipulated PGCs were transferred to recipient embryos (White Leghorn, WL) and migration to the germinal ridges was analysed by examining GFP gene expression in the gonads of recipient embryos under UV light at x40 magnifications. The expression of GFP gene was detected in all the gonads of recipient embryos examined up to 10.5 d of culture. 3. Migration of PGCs irradiated with soft X-rays to the germinal ridges was also confirmed by detecting a single nucleotide polymorphism in the D-loop region of the mitochondrial DNA of BPR and WL chickens. Freshly collected PGCs (BPR) were transferred to the bloodstream of recipient embryos (WL). The fate of the transferred donor PGCs was traced by detecting the single nucleotide polymorphism in the D-loop region of the mitochondrial DNA in BPR and WL used in this study. Transferred donor PGC-derived cells were detected in all the gonads of 17-d cultured embryos by PCR. 4. The results suggest that PGCs irradiated with soft X-rays still retain the ability to migrate to the germinal ridges of recipient embryos.     

Allele‐specific polymerase chain reaction typing and sequencing of mitochondrial D‐loop region in broiler chickens in Japan

This study aimed to comprehend a feature of single nucleotide polymorphism (SNP) in mitochondrial DNA (mtDNA) mainly of general broiler chickens in Japan. We typed two SNP sites (199C/T and 792A/G) of the D‐loop region in mtDNA by allele‐specific PCR (AS‐PCR) in 359 broiler (182 chunky and 177 cobb) and 506 layer (233 White Leghorn, 140 Barred Plymouth Rock and 133 Rhode Island Red) chickens. The SNP of 199C or 792A by AS‐PCR was observed in the chunky and cobb chickens, and not in the layers. The haplotype 199T/792G was observed in a part of cobb and all layers. By the result of AS‐PCR haplotyping and the broiler brands, the D‐loop region was sequenced in 44 broiler chickens (20 chunky and 24 cobb) and compared with the layers’ sequence data. Among the broiler and layer chickens, 21 SNP sites (including one insertion) and 11 sequence haplotypes were observed. Haplotype variation or correspondence was observed in and between the broiler brands. This study provides important information to establish a chicken meat traceability system by SNP haplotyping of mtDNA in Japan.     

Large-scale survey of frequency of forest walking and related factors in a Japanese population inhabiting a large city, and comparison of an urban area and a rural area

The frequency of forest walking among the general population is a major topic of study in forest science. The objectives of this study were threefold: to assess the frequency of forest walking among Japanese residents of Nagoya, a large city; to evaluate differences among frequency of forest walking by participants from a large city, an urban area (Shizuoka; 4,666 participants), and a rural area (Yakumo Town, Hokkaido; 397 participants) in previous studies; and to examine factors related to frequency of forest walking. The survey, by self-administered questionnaire, in the major city of Nagoya was conducted between June 2008 and May 2010. In all, 5,158 participants (M/F, 1,466/3,692; mean age ± SD [range], 52.5 ± 10.3 [35–69] years) were included in the analysis. The proportions of frequency of forest walking ≥ once/month and ≥ once/year were 10.9 % (M/F, 15.1/9.3 %) and 46.1 % (51.0/44.1 %), respectively. In multiple logistic regression analysis, significant differences were noted among study sites for the adjusted odds ratio for frequency of forest walking. Overall, the order of highest to lowest frequency of forest walking was Shizuoka > Nagoya > Yakumo. Factors related to frequency of forest walking were common among the three study sites. Higher frequency of forest walking was associated with male sex and older age; the most relevant factor related to frequency of forest walking was its enjoyment level. Further studies will be required to clarify why these factors are related to frequency of forest walking.