Lactobacillus rhamnosus GG SpaC pilin subunit binds to the carbohydrate moieties of intestinal glycoconjugates

Lactobacillus rhamnosus GG (LGG) is a well‐established probiotic strain. The beneficial properties of this strain are partially dependent on its prolonged residence in the gastrointestinal tract, and are likely influenced by its adhesion to the intestinal mucosa. The pilin SpaC subunit, located within the Spa pili structure, is the most well studied LGG adhesion factor. However, the binding epitopes of SpaC remain largely unknown. The aim of this study was to evaluate the binding properties of SpaC to the carbohydrate moieties of intestinal glycoconjugates using a recombinant SpaC protein. In a competitive enzyme‐linked immunosorbent assay, SpaC binding was markedly reduced by addition of purified mucin and the mucin oligosaccharide fraction. Histochemical staining revealed that the binding of SpaC was drastically reduced by periodic acid treatment. Moreover, in the surface plasmon resonance‐based Biacore assay, SpaC bound strongly to the carbohydrate moieties containing β‐galactoside at the non‐reducing terminus of glycolipids. We here provide the first demonstration that SpaC binds to the oligosaccharide chains of mucins, and that the carbohydrate moieties containing β‐galactoside at the non‐reducing termini of glycoconjugates play a crucial role in this binding. Our results demonstrate the importance of carbohydrates of SpaC for mucus interactions.     

Effects of a high milk intake during the pre‐weaning period on nutrient metabolism and growth rate in Japanese Black cattle

This study aimed to determine the effects of feeding an increased volume of high‐fat milk during the early post‐natal life on metabolite concentrations in the blood, the expression of key genes regulating intermediary metabolism in the skeletal muscles, and the rate of growth of Japanese Black cattle. All calves were fed a high‐fat milk replacer (crude protein, 26%; crude fat, 25.5%; total dissolved nitrogen, 116%). Control calves (n = 4) were nursed with 500 g milk replacer until 3 months of age, whereas calves in the experimental group (n = 4) were nursed with 1800 g milk replacer until 3 months, and then the volume was gradually reduced until 5 months. Body weight was significantly higher in the experimental group than in the control group at 7 months. Plasma glucose concentrations were significantly lower in the experimental group. Expression of glucose‐transporter‐4 messenger RNA (mRNA) was lower, whereas that of glucose transporter 1, cluster of differentiation 36, and carnitine palmitoyltransferase‐1b mRNA was significantly higher in the Longissimus thoracis of the experimental group. Nutritional status during early post‐natal life appears to strongly influence the growth rate and glucose and lipid metabolism in Japanese Black cattle.     

Assessment of rabbit spleen size using ultrasonography

Assessment of spleen size using the ultrasonography has become a standard practice in human. However, the assessment is not established method in experimental animals. To establish the index to assess the spleen size using ultrasonography, we measured the cross-section image of rabbit spleen during endotoxin shock. The image of the cross-section was appeared as triangle, and the height of the triangular image was defined as the spleen index. This spleen index showed strong correlation with the spleen weight. In conclusion, this method is suitable for observation of changes in rabbit spleen size and may reduce the number of rabbit in the longitudinal studies.     

Androgen induces production of male effect pheromone in female goats

Previously we showed that the primer pheromone responsible for the "male effect" was produced in specific skin regions of castrated male goats by androgen treatments. In the present study, we examined whether androgen can also induce production of the male effect pheromone in female goats. Capsules containing dihydrotestosterone (DHT) or testosterone (T) were subcutaneously implanted into six ovariectomized (OVX) goats for 28 days. Small skin samples were collected from the head and rump regions, and the pheromone activity of their ether extracts was examined using a bioassay that monitors the electrophysiological manifestation of the hypothalamic gonadotropin-releasing hormone pulse generator as multiple-unit activity. Behaviors of OVX goats towards ovary-intact estrous goats were also examined before and at the end of DHT or T treatment. Before androgen treatment, neither the head nor rump skin samples in OVX goats showed pheromone activity. DHT treatment induced pheromone activity in the head skin sample of six OVX goats and in the rump skin sample of two OVX goats. Similar results were obtained by T treatment. In addition, OVX goats treated with T showed masculine-type sexual behaviors such as courtship and mounting behaviors towards the estrous goats. These results demonstrate that androgen is capable of inducing primer pheromone activity in the female and suggest that the synthesis pathway of the male effect pheromone exists in both sexes in the goat.     

草地贪夜蛾对我国玉米产业的潜在经济损失评估

草地贪夜蛾Spodoptera frugiperda,又称秋黏虫,起源于美洲。自2019年1月入侵我国云南以来,目前已扩散至我国25个省、市(区)。目前在我国发现的草地贪夜蛾主要为害玉米,本研究在收集了草地贪夜蛾的为害及防治情况,玉米的产量、面积、价格等相关数据的基础上,利用随机模型@RISK分别预测了其在防治与不防治场景下对我国玉米产业的潜在经济损失。结果表明,在不防治场景下,草地贪夜蛾对我国玉米的潜在经济损失总量的90%置信区间为375.68亿～3 283.45亿元,投入防治后可挽回的潜在经济损失90%置信区间为254.78亿～2 918.93亿元。因此,为保护我国玉米种植业的安全生产,应加强田间防治来降低其对我国玉米产业造成的潜在经济损失。     

木耳菌渣稻苗基质化利用难点及解决技术

为有效转化利用废弃木耳菌渣,解决木耳菌渣稻苗基质化利用过程中出现的稻苗黄化现象问题,通过分析木耳菌渣理化性质及对水稻种子采取硫酸亚铁溶液浸种处理的方法,进行木耳菌渣稻苗基质化利用研究。结果表明:1)虽然腐熟菌渣的有机质含量、保水性及速效养分等特性有利于做水稻育苗基质,但盐分浓度较高、偏碱性、密度较小不适宜单一菌渣做育苗基质;2)单一菌渣基质培育稻苗,会出现黄化现象,原因在于单一菌渣基质有效铁含量偏低,造成了叶片含铁量少;3)硫酸亚铁浸种处理可以控制稻苗黄化现象,但会诱导植株株高伸长;4)0.014mol/L硫酸亚铁与0.051mmol/L多效唑混合浸种液在20℃下浸种处理3d,能够有效控制稻苗黄化现象和植株的徒长。同体积的腐熟菌渣和稻田土混合配制成的育苗基质,稻种采用硫酸亚铁溶液与多效唑溶液混合浸种处理的方法,能够育出壮实的大龄机插秧苗。     

金针菇不亲和性因子研究

从29株金针菇(Flammulina velutipes)中经单孢分离获得的单核菌株,两两配对后,在显微镜下观察锁状联合,配对结果将金针菇的A因子确定到10个,B因子确定到8个.13个黄色菌株的不亲和性因子包含了从A1到A9,B1到B8;而16个白色菌株的不亲和性因子大多为A2A3B2B3类型.有24个金针菇菌株获得的单核菌丝有4种交配型且符合1∶1∶1∶1比例,其它菌株获得的单核菌丝交配型与理论数据有偏离.     

Ecology,physiology and genetics of a phycodnavirus infecting the noxious bloom-forming raphidophyte <Emphasis Type="Italic">Heterosigma akashiwo</Emphasis>

Abstract:   Heterosigma akashiwo virus (HaV) is a large icosahedral virus (∼0.2 μm) harboring a double-stranded DNA (dsDNA) genome (∼294 kbp). The virus is the only member of the genus Raphidovirus in the family Phycodnaviridae. Since its first discovery, a number of ecologic, physiologic and genetic studies about HaV have been conducted; especially, the relationship between H. akashiwo and HaV in nature was studied and viral infection is now regarded as a significant factor influencing the dynamics and termination of H. akashiwo blooms. HaV infection has considerable impacts on H. akashiwo populations in both aspects of fluctuation in biomass (quantity) and changes in clonal composition (quality). Partial sequencing of the HaV genome revealed that a number of genes showed considerable similarity to those of other protist-infecting viruses; still, the phylogenetic position of HaV suggested a number of enigmas in host–virus coevolution. Here are summarized the ecology, physiology and genetics of HaV especially from the viewpoint of the host–virus relationship.     

根癌农杆菌介导ACS反义基因转化香蕉的研究

以香蕉(Musa spp.)品种‘天宝蕉’(Musa spp.,AAA类群)为试材,对以根癌农杆菌介导法的香蕉遗传转化体系进行较全面的研究,并以该系统进行了ACS反义基因转化香蕉的研究。结果表明:不经预培养的香蕉茎尖横切薄片,侵染前用附加0.1 mg/L甘露醇的高渗固体培养基前处理4 h,农杆菌重悬液浓度为OD600在1.0左右,重悬液中含100 g/L蔗糖,接菌时间为10~15 min,于26℃黑暗条件下共培养4 d,共培养培养基pH值为5.8是较为适合的转化条件;采用附加100 mg/L卡那霉素、2 mg/L AgNO3筛选培养基对共培养后的香蕉横切薄片进行筛选,共获得5个转ACS反义基因的抗性芽系;经GUS组织化学法及PCR检测,gus基因已整合进香蕉基因组。     

快速脱水抑制葡萄干制过程中膜脂过氧化及褐变

为探索脱水速度对无核白葡萄干制过程中膜脂过氧化作用及褐变的影响,以新疆无核白葡萄为试验材料,经过葡萄促干剂处理后,采用快速脱水和缓慢脱水2种处理,质量每减轻10%进行取样,测定脱水过程中果实干基含水率、干燥速率、褐变度、细胞膜透性、丙二醛(malonaldehyde,MDA)含量、脂氧合酶(lipoxygenase,LOX)、超氧化物歧化酶(superoxide dismutase,SOD)、过氧化氢酶(catalase,CAT)、过氧化物酶(peroxidase,POD)、多酚氧化酶(polyphenol oxidase,PPO)活性以及总酚含量的变化。结果表明:与缓慢脱水相比,快速脱水处理显著(P0.05)降低了无核白葡萄褐变度的上升,减少MDA生成量以及膜透性的增加,抑制LOX活性的升高,保持较高的活性氧清除酶SOD、CAT及POD活性及较高的总酚含量,且使PPO活性保持在一个较低的水平。因此认为,快速脱水可以有效地抑制无核白葡萄的膜脂过氧化作用对细胞膜的破坏,保持细胞的完整性,且PPO活性较低,从而减少无核白葡萄脱水褐变的发生。研究结果为快速脱水在无核白葡萄干制中的应用提供参考。