Staging and the time course of embryonic development in kurosoi,Sebastes schlegeli

Synopsis Intraovarian development of embryos was observed in 31 female rockfish kurosoi,Sebastes schlegeli, which had been raised in the laboratory. Three of the females had newly fertilized eggs; the others' embryos were at various stages. The developmental series (33 stages) was not very different from that in oviparous fishes. However, several characteristic features were noted: thin egg envelope, narrow perivitelline space, elliptical encapsulated embryo in the late stages and depletion of yolk at parturition. The time course of development up to birth at different temperatures was adjusted to that at 9.8°C using the Arrhenius equation and processed for the relationship between the stage number (X) and stage-to-birth time in days (Y). An equation, was obtained, and the gestation period was calculated to be 48 days at 9.8°C.     

Effect of HPr phosphorylation on structure,dynamics, and interactions in the course of transcriptional control

The serine46-phosphorylated form of the bacterial protein HPr fulfils an essential function in carbon catabolite repression (CCR). Using molecular dynamics (MD) we studied the effect of Ser46 phosphorylation on the molecular properties of HPr and its capability to act as the co-repressor of carbon catabolite protein A (CcpA). The calculated pK (a) values for a representative set of HPr(Ser46P) structures indicate that the phosphate group of HPr(Ser46P) exists predominantly in the unprotonated form under neutral conditions. A hydrogen bond detected in HPr(Ser46P) between one phosphate-group oxygen and a side-chain hydrogen of Asn43-an amino acid conserved in all HPr proteins of Gram-positive bacteria that regulate their carbon consumption by CCR-might fulfil an important role in CcpA-HPr(Ser46P) complex formation. MD simulations show that the Ser46P-Asn43 hydrogen bond present in the unbound structure is replaced by intermolecular interactions upon complex formation. The degree to which amino acids in the CcpA-HPr(Ser46P) interface contribute to cofactor binding was analyzed by in silico alanine scanning. Lys307, Arg303, Asp296, Val300, and Tyr295 of CcpA were identified as important amino acids for the CcpA-HPr(Ser46P) interaction. Three of these residues are directly involved in sensing the correct phosphorylation state at His15(HPr) and Ser46(HPr). A substitution of interface residues Val319, Val314, Ser316, Leu321 and Gln320 by alanine showed that these amino acids, which contact helix alpha2 of HPr(Ser46P), play a less prominent role for complex formation.     

Overwintering of annual bluegrass weevils, Listronotus maculicollis, in the golf course landscape

Annual bluegrass weevil, Listronotus maculicollis (Dietz) (Coleoptera: Curculionidae), adults overwinter in protected areas but their life cycle is completed on highly maintained turfgrass. To better target control tactics on affected golf courses, we need to understand the relationship between overwintering and developmental habitats. Our objectives were to identify factors that influence overwintering site selection and to gather evidence of directional movement. Surveys of natural field populations were conducted in early spring over 2 years to test how abundance of overwintered adults depends on microhabitat (surface composition) and distance from the developmental habitat. The influence of microhabitat on overwintering preference and success was further tested in a multiple‐choice and no‐choice field experiment by relocating overwintering weevils into experimental arenas where four microhabitats were presented together or singly. The timing and direction of dispersal by walking adults was assessed using paired linear pitfall traps. Results showed that adults could overwinter up to 60 m from the fairway and 10 m into the woods. They were most abundant near the tree line; none were detected within 5 m of the fairway. Microhabitat had a significant effect on abundance in 1 year, being highest in mixed tree litter followed by moss, high‐cut grass, and pine litter. Under multiple‐choice conditions, high‐cut grass was preferred over low‐cut grass and leaf litter, followed by pine litter. Pitfall trap captures showed a peak of activity in the spring, and at one site this was directional toward the fairway. There was no directionality or increase in activity in the fall. Based on these results, a new conceptual model of flux between habitats is proposed based on orientation of flying adults to defined tree lines. Defining this behavior will strengthen our ability to target control tactics in space and time against this major turf pest.     

Obesity, overweight, and their life course trajectories in veterans and non-veterans

Veterans comprise a large and growing segment of the US population. Results from national telephone surveys suggest higher prevalence of overweight among Veterans compared with demographically similar non-Veterans, based on self-reported height and weight. Using 1999-2008 data from the National Health and Nutrition Examination Survey (NHANES), we compared 3,768 Veterans and 21,974 non-Veterans on: (i) several measures of adiposity based on direct anthropometry; (ii) life-course of self-reported BMI; and (iii) behaviors related to weight loss or maintenance. Whether Veterans were more likely than demographically similar non-Veterans to be obese or overweight depended on the adiposity measure employed. On BMI, Veterans were about equally likely to be obese (30+ kg/m(2)), but more likely to be overweight (25-29.9 kg/m(2)) by both self-report and by direct measurement (significantly so only by self-report). On waist-stature ratio, a roughly similar pattern was observed. On waist circumference, Veterans tended to have larger values than demographically similar non-Veterans, with more Veterans in the largest two categories. But on dual-photon X-ray absorptiometry, Veterans were less likely to have 35+% body fat than non-Veterans of similar age, gender, and race/ethnicity. Life-course trends in self-reported BMI suggested a possible burst of weight gain after military discharge. These results suggest that Veterans may, on average, have less excess body fat than non-Veterans--a pattern not revealed by standard anthropometric measures.     

大学生科学素质教育课程“走进微生物世界”的建设与实践

微生物学的研究和应用在人类社会发展中起着越来越重要的作用。微生物与人类的生产和生活密切相关,开展微生物学方面的素质教育非常必要。因此,我们面向非生物专业本科生开设了"走进微生物世界"素质教育课程。根据学生的知识水平和认知规律,本课程重视知识体系的系统性和关联性,基础理论、生产应用和实践教学等教学内容依次展开,开拓学生视野,培养创新思维。不同的教学内容采用了差别化的教学方法,配合多媒体教学、网络教学和基于云课堂的即时互动教学,提高学生的学习兴趣,学习效果回馈及时,方便师生交流。经过3年的建设,本课程已形成教学方法有特色、教学内容符合学生知识水平和学科发展潮流的素质教育课程。     

The hemocytes of Heliothis armigera: Ultrastructure,functions, and evolution in the course of larval development

Five types of hemocytes, prohemocytes, typical plasmatocytes, coagulocytes, spherule cells, and oenocytoides, have been defined in the last larval instar of Heliothis armigera on the basis of ultrastructural microscopy, smears, and optical phase-contrast microscopy. Modifications in typical plasmatocytes and coagulocytes have been evidenced in the course of development in this instar, which suggests that these hemocytes are involved in physiological processes of development. Only coagulocytes exhibit endocytotic capacities. Phenoloxidase activity was observed in oenocytoides.     

Membrane disruption, fusion and resealing in the course of exocytosis in Paramecium cells

Ca²⁺-ionophore-mediated trichocyst exocytosis was followed by scanning electron microscopy, freeze-cleaving and ultrathin sectioning after surface labelling in vivo with negatively charged hemepeptides. The apical trichocyst membrane and the superposed cell membrane portion (encircled by ˜300 nm large “rings” of membrane-intercalated particles) undergo fragmentation, while both membranes involved fuse with each other within the “rings”. Subsequently cell membrane materials spread centropetally to the region within the “rings” allowing the cell membrane to become resealed and the trichocyst membrane to become detached. Exocytosis does not result in any remarkable integration of trichocyst membrane materials into the cell membrane.     

The course and mortality of a hematopoietic neoplasm in the soft-shell clam,Mya arenaria

Results from two experiments containing approximately 280 Mya arenaria indicated that significantly higher (P < 0.05) mortality occurred within the neoplastic clam population than in the nonneoplastic clam population. Using an in vivo blood cytological technique, five levels of severity were established. The levels were based on the number of neoplastic cells in the circulation with level 1 as the lowest severity and level 5 as the highest severity. Neoplastic clams that were diagnosed as the lowest level had higher survival rates (60%) than those clams diagnosed as the highest level (0%). The hematopoietic neoplasm in M. arenaria followed one of three courses: (1) in approximately 50% of the neoplastic clams the disease progressed to a higher severity and resulted in death; (2) in approximately 40% of the neoplastic clams the disease was chronic, i.e., remained at a stable level; and (3) in approximately 10% of the neoplastic clams the disease diminished in severity or disappeared entirely. In addition, 10% of the clams diagnosed as nonneoplastic at the beginning of the experiments were neoplastic by the termination of the experiment. The contraction of the disease may have been de novo or by stimulation of latent infections.The prevalence of the neoplasm in clams collected from an epizootic area followed a biphasic seasonal pattern. The highest prevalences occurred in October, November, and in May. The hematopoietic neoplasm in M. arenaria was also age and species specific.