茶刺蛾颗粒体病毒的分离与鉴定

茶刺蛾[Darna trima(more)]＊属鳞翅目刺蛾科,危害多种果树林木。1985年我们从四川珙县某茶园内自然罹病死亡的茶刺蛾幼虫中,分离到一种茶刺蛾病原物。通过纯化后,经感染试验、电镜形态观察、超微结构研究等,结果确定该病原物为一种颗粒体病毒。     

Temporal relationships betweenZea mays,ostrinia nubilalis (Lep.: Pyralidae) and endophyticBeauveria bassiana

The entomopathogenic fungus,Beauveria bassiana (Balsamo) Vuillemin, was applied to whorl-stage (V7) corn,Zea mays L., by foliar application of a granular formulation of corn grits containing conidia or by injection of a conidial suspension. All plants were infested with European corn borer larvae,Ostrinia nubilalis (Hübner), at the V7 (whorl), V12 (late-whorl), or V17 (pretassel) stage of plant development. Plants infested at whorl and late-whorl stages had significantly more European corn borer tunneling than did plants infested at the pretassel stage. The percentage of plants colonized byB. bassiana did not differ significantly among the whorl, late-whorl, and pretassel stages. As the plants matured,B. bassiana was isolated from different plant areas, with the pith more frequently colonized than the leaf collars. Foliar application ofB. bassiana provided immediate suppression ofO. nubilalis in those plants infested at whorl stage. The reduced efficacy ofB. bassiana at the intermediate plant stages relative to efficacy at harvest is discussed. The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over other firms or similar products not mentioned.     

Ultrastructural localization of oxidative and peroxidative activities in a carrot suspension cell culture

Summary Oxidative and peroxidative activities were localized at the ultrastructural level in suspension cells of an anthocyanin-producing strain of carrot after treatment with dihydroxyphenylalanine (DOPA) and diaminobenzidine (DAB). In DOPA-treated cells a reaction ascribed to polyphenoloxidase (PPO) occurred in the thylakoids of plastids. After DAB treatment at pH 9.0 reactions occurred in microbodies and plastid thylakoids; after treatment at pH 6.8 additional reactions occurred in the mitochondrial cristae and cytoplasmic ground substance. No reaction occurred in the cell walls at either pH. A reaction could not be unequivocally detected in the vacuoles because of the natural occurrence of osmiophilic material. Application of peroxidase and PPO inhibitors indicated that four distinct systems were involved in the DAB reactions: catalase was correlated with the reaction in the microbodies, peroxidase with the reaction in the cytoplasmic ground substance, cytochromes with the mitochondrial reaction, and PPO with the reaction in the thylakoids of the plastids.Contribution No. 1964 of the Rhode Island Agricultural Experiment Station.     

Ultrastructural cytochemistry of atrial muscle cells

Summary Sections of atrial cardiocytes from young rats were subjected to radioautography after a single intravenous injection of L-leucine-4,5 ³H to identify the sites of synthesis and to follow the migration of newly-formed proteins. As early as 2 min after injection of L-leucine ³H, the label was highest in the rough endoplasmic reticulum (RER), suggesting that cisternal ribosomes are sites of protein synthesis. By 5 min, most of the label had migrated from the RER to the Golgi complex. Some label was already present over specific granules by 2 min but the peak was reached at 1 h. By 4 h, the label over the specific granules had diminished, possibly indicating a release of newly-synthetized secretory material outside the cell. The label over myofilaments and Z-bands was relatively high at most time intervals, suggesting an early and important incorporation of leucine into the contractile and structural proteins of these organelles. The label over the cytosol was initially high and increased even further at 5 and 20 min but decreased to a very low level at 4 h. In contrast, the label over the cell surface rose continuously and peaked at 4 h. The pattern of increment of the label over the cell surface suggests that the newly-formed proteins of these sites are also synthetized in the RER, pass through the Golgi complex and are transported in the cytosol before reaching their destination.     

Isolation of an iridovirus from two terrestrial isopods,the pill bug, Armadillidium vulgare, and the sow bug, Porcellio dilatatus

An iridovirus was isolated from two terrestrial isopods (class Crustacea, order Isopoda), the pill bug, Armadillidium vulgare, and the sow bug, Porcellio dilatatus, collected in southern California. The isolates have been designated Type 31 (from A. vulgare) and Type 32 (from P. dilatatus). Diseased isopods were recognized by a characteristic blue discoloration of the normally gray cuticle. Based on the relative number of virions observed in diseased cells, viral replication was most extensive in epidermal, muscle, and adipose tissue. Additionally, small clusters of midgut epithelial cells were heavily infected in many specimens, although replication throughout this tissue was never observed. Nerve and reproductive tissues were lightly infected. Infection was not observed in hemocytes or the hepatopancreatic caeca. Virions of both isolates measured ca. 125 nm in diameter in ultrathin sections and 141 nm in negatively stained preparations, and formed paracrystalline arrays in heavily infected cells. The isolation of a typical iridovirus from isopods further demonstrates that the natural host range of this virus group extends beyond the class Insecta.     

Neuroglandular contacts between vasopressin-reactive fibers and cells of the pars tuberalis in the rat

Summary In electron micrographs fibers containing vasopressin-immunoreactive elementary granules 100–120 nm in diameter are observed within the basal lamina of the adenohypophyseal pars tuberalis adjacent to the rostral portion of the median eminence. The concept of a neuroglandular transmitter function of vasopressin is discussed.Supported by the Deutsche Forschungsgemeinschaft (Grant Nr. Kr. 569/2) and the Stiftung VolkswagenwerkThe excellent technical assistance of Mrs. Helga Prien is thankfully acknowledged     

Postmortem observations on rumen wall histology and gene expression and ruminal and caecal content of beef cattle fattened on barley-based rations

Sub-acute ruminal acidosis (SARA) can reduce the production efficiency and impair the welfare of cattle, potentially in all production systems. The aim of this study was to characterise measurable postmortem observations from divergently managed intensive beef finishing farms with high rates of concentrate feeding. At the time of slaughter, we obtained samples from 19 to 20 animals on each of 6 beef finishing units (119 animals in total) with diverse feeding practices, which had been subjectively classified as being high risk (three farms) or low risk (three farms) for SARA on the basis of the proportions of barley, silage and straw in the ration. We measured the concentrations of histamine, lipopolysaccharide (LPS), lactate and other short-chain fatty acids (SCFAs) in ruminal fluid, LPS and SCFA in caecal fluid. We also took samples of the ventral blind sac of the rumen for histopathology, immunohistopathology and gene expression. Subjective assessments were made of the presence of lesions on the ruminal wall, the colour of the lining of the ruminal wall and the shape of the ruminal papillae. Almost all variables differed significantly and substantially among farms. Very few pathological changes were detected in any of the rumens examined. The animals on the high-risk diets had lower concentrations of SCFA and higher concentrations of lactate and LPS in the ruminal fluid. Higher LPS concentrations were found in the caecum than the rumen but were not related to the risk status of the farm. The diameters of the stratum granulosum, stratum corneum and of the vasculature of the papillae, and the expression of the gene TLR4 in the ruminal epithelium were all increased on the high-risk farms. The expression of IFN-γ and IL-1β and the counts of cluster of differentiation 3 positive and major histocompatibility complex class two positive cells were lower on the high-risk farms. High among-farm variation and the unbalanced design inherent in this type of study in the field prevented confident assignment of variation in the dependent variables to individual dietary components; however, the CP percentage of the total mixed ration DM was the factor that was most consistently associated with the variables of interest. Despite the strong effect of farm on the measured variables, there was wide inter-animal variation.     

Stejneger's beaked whale strandings in Alaska, 1995–2020

Presented here is the first comprehensive and updated compilation of history, distribution, and findings of Stejneger's beaked whales (Mesoplodon stejnegeri) in Alaska. Stejneger's beaked whales are a poorly understood, elusive, deep-diving cetacean species found in the North Pacific Ocean. Since Stejneger's beaked whale strandings data in Alaska through 1994 were last published, 35 additional strandings have been documented. Twenty-seven animals stranded in the Aleutian Islands, seven stranded in Southcentral Alaska, and one animal stranded on St. Lawrence Island. Twenty-two carcasses were necropsied, but only four were fresh. Seventeen of the 22 died during mass stranding events and cause of death could not be definitively determined. Barotrauma was suspected in three cases and infectious disease possibly complicated by barotrauma occurred in two cases. We documented an expansion of strandings into the northern Bering Sea, characterized a sex bias, examined stomach contents that included macroplastic, and identified parasites not previously associated with Stejneger's beaked whales. Also included are data on the largest known mass stranding of Stejneger's beaked whales, which occurred on Adak Island in 2018. The history, distribution, and findings presented here are central to further our understanding of this species.