全放牧婆罗门牛和BMY牛胚胎回收适期的探讨

选用婆罗门牛和BMY牛供体超数排卵,以第1次人工授精（AI）当日为0d,分别在AI第6～6．5天、7—7．5天和8—8．5天回收胚胎,统计≤16细胞胚、桑椹胚、囊胚和孵化胚的数量,计算各发育阶段胚胎所占的百分率,分析婆罗门牛和BMY牛的胚胎回收适期。结果表明：婆罗门牛AI第6～6．5天的桑椹胚率比BMY牛高43．54个百分点（P〈0．01）,AI第8～8．5天的孵化胚率比BMY牛高35．94个百分点（P〈0．05）,胚胎发育速度比BMY牛较快。罗门牛和BMY牛在AI第6～6．5天回收胚胎的囊胚率低,而第8—8．5天的孵化胚率高,胚胎回收以AI第7—7．5天为宜。     

Synthetic surfactants for protecting cultured fish against toxic phytoplankton

Polyoxyethylene alkyl esters, which are surface-active agents, were chemically synthesized from fatty acids (C₁₂-C₁₈) on reaction with different moles of polyethylene oxides, and were tested for effectiveness against the toxic raphidophytes Chattonella marina (Subrahmanyan) Hara & Chihara and C. antiqua (Hada) Ono. The synthetic surfactants destroyed cultured cells from these two species. Although the synthetic surfactants also exhibited ichthyotoxicity, this was lowered by increasing the molarity of ethylene oxide (EO) in alkyl ester molecules. Young yellowtail, Seriola quinqueradiata Temminck & Schlegel, survived exposure to C. marina (5000-5500 cells mLT^?1) or C. antiqua (3000-3500 cells mL^?1) cultures with the addition of 4-5 p.p.m. oleyl ester EO 14, but died within an hour without the addition of this surfactant.     

Geographic Variations in the Toxin Profile of the Xanthid Crab Zosimus aeneus in a Single Reef on Ishigaki Island,Okinawa, Japan

Toxic crabs of the family Xanthidae contain saxitoxins (STXs) and/or tetrodotoxin (TTX), but the toxin ratio differs depending on their habitat. In the present study, to clarify within reef variations in the toxin profile of xanthid crabs, we collected specimens of the toxic xanthid crab Zosimus aeneus and their sampling location within a single reef (Yoshihara reef) on Ishigaki Island, Okinawa Prefecture, Japan, in 2018 and 2019. The STXs/TTX content within the appendages and viscera or stomach contents of each specimen was determined by instrumental analyses. Our findings revealed the existence of three zones in Yoshihara reef; one in which many individuals accumulate extremely high concentrations of STXs (northwestern part of the reef; NW zone), another in which individuals generally have small amounts of TTX but little STXs (central part of the reef; CTR zone), and a third in which individuals generally exhibit intermediate characteristics (southeastern part of the reef; SE zone). Furthermore, light microscopic observations of the stomach contents of crab specimens collected from the NW and CTR zones revealed that ascidian spicules of the genus Lissoclinum were dominant in the NW zone, whereas those of the genus Trididemnum were dominant in the CTR zone. Although the toxicity of these ascidians is unknown, Lissoclinum ascidians are considered good candidate source organisms of STXs harbored by toxic xanthid crabs.     

Role of the gelatinous layer (G-layer) on the origin of the physical properties of the tension wood of Acer sieboldianum

The tension wood (TW) properties of a 70-year-old specimen of Acer sieboldianum Miq. were analyzed by using the G-fiber model that was proposed in our previous report. The roles of the G-layer on the origins of (1) a high tensile growth stress, (2) a large longitudinal Young’s modulus, and (3) a high longitudinal drying shrinkage in the TW xylem are discussed on the basis of the simulations using the G-fiber model. The results suggest that the G-layer generates a high tensile stress in the longitudinal direction during xylem maturation; the longitudinal Young’s modulus of the green G-layer becomes significantly higher than that of the lignified layer; furthermore, the G-layer tends to shrink extraordinarily more than that of the lignified layer during moisture desorption.This report follows the previous report “Role of the gelatinous layer on the origin of the physical properties of the tension wood.” J Wood Sci (2004) 50:197–208. Part of this paper was presented at the 49th Annual Meeting of the Japan Wood Research Society, Tokyo, April 1999, and at the 2nd International Conference of the European Society for Wood Mechanics, Stockholm, May 2003This revised version was published online in July 2005. On pages 228–230 the character was replaced by a vertical line.     

Subacute and delayed toxicity of iminoctadine liquid formulation,which contains iminoctadine triacetate as an antifungal component on a nontarget domesticated insect,the silkworm,Bombyx mori L. (Lepidoptera: Bombycidae)

We investigated insecticidal effects of iminoctadine liquid formulation, a fungicide containing iminoctadine triacetate, on the silkworm Bombyx mori that is an important domesticated insect. Iminoctadine liquid formulation was incorporated in an artificial diet and fed to silkworms for 24 h on the first day of either the third or fourth instar, thereafter reared without the fungicide. Third instar larvae that ingested the diet containing 1% (wt/wt) iminoctadine liquid formulation died within 24 h (subacute toxicity), and those that ingested either 0.1% or 0.3% iminoctadine liquid formulation developed to the pharate fourth stage and then became deficient in molting (delayed toxicity). In fourth instar larvae, iminoctadine liquid formulation exhibited subacute toxicity and delayed toxicity at 0.3% and >1%, respectively. Furthermore, we fed the larvae a diet with iminoctadine liquid formulation for 24 h at different intervals in the inter-molting period of the third and fourth instar. Iminoctadine liquid formulation administered at an earlier stage in the inter-molting period exerted a more severe effect than a later administration. Iminoctadine triacetate, an anti-fungal ingredient in the iminoctadine liquid formulation, exhibited toxicity similar to that of the liquid formulation.     

Characteristic features of porcine endogenous retroviruses in Vietnamese native pigs

We aimed to clarify the genomic characteristics of porcine endogenous retroviruses (PERVs) in Vietnamese native pig (VnP) breeds. First, we investigated genetic polymorphisms in β‐ and γ‐like PERVs, and we then measured the copy numbers of infectious γ‐like PERVs (PERV‐A, B, and C). We purified genomic DNA from 15 VnP breeds from 12 regions all over the country and three Western pig breeds as controls, and investigated genetic polymorphisms in all known PERVs, including the beta (β)1–4 and gamma (γ)1–5 groups. PERVs of β1, β2, β3, and γ4 were highly polymorphic with VnP‐specific haplotypes. We did not identify genetic polymorphisms in β4, γ1, or γ2 PERVs. We then applied a real‐time polymerase chain reaction–based method to estimate copy numbers of the gag, pol, and env genes of γ1 PERVs (defined as A, B, and C). VnP breeds showed significantly lower copy number of the PERV genes compared with the Western pig breeds (on average, 16.2 and 35.7 copies, respectively, p < .05). Two VnP breeds showed significantly higher copy number compared with the other VnPs (p < .05). Our results elucidated that VnPs have specific haplotypes and a low copy number of PERV genes.     

Variational bayesian method of estimating variance components

We developed a Bayesian analysis approach by using a variational inference method, a so‐called variational Bayesian method, to determine the posterior distributions of variance components. This variational Bayesian method and an alternative Bayesian method using Gibbs sampling were compared in estimating genetic and residual variance components from both simulated data and publically available real pig data. In the simulated data set, we observed strong bias toward overestimation of genetic variance for the variational Bayesian method in the case of low heritability and low population size, and less bias was detected with larger population sizes in both methods examined. The differences in the estimates of variance components between the variational Bayesian and the Gibbs sampling were not found in the real pig data. However, the posterior distributions of the variance components obtained with the variational Bayesian method had shorter tails than those obtained with the Gibbs sampling. Consequently, the posterior standard deviations of the genetic and residual variances of the variational Bayesian method were lower than those of the method using Gibbs sampling. The computing time required was much shorter with the variational Bayesian method than with the method using Gibbs sampling.