球孢白僵菌生长及毒力影响因子的研究进展

随着害虫综合治理的提出，昆虫病原真菌在防治农林害虫上的应用日趋广泛，白僵菌是世界各国研究应用最多的真菌杀虫剂。从白僵菌生长所需的营养、温湿度条件等方面的研究进展进行阐述，总结了提高菌株生长水平和杀虫效果的主要措施，以期对今后白僵菌的培养及应用提供参考。     

ELISA在苏云金杆菌杀虫蛋白毒素检测中的应用及新进展

苏云金杆菌是目前应用较广泛的生物杀虫细菌之一，其产生的杀虫蛋白毒素是主要的杀虫成分，目前对苏云金杆菌的毒力和杀虫蛋白毒素的检测主要采用生物测定、SDS-PAGE等方法，但这些方法的灵敏度较差。本文综述了酶联免疫吸附分析法在苏云金杆菌蛋白毒素检测中的应用，以及在检测中采用的ELISA的类型和基本原理，并对其应用前景进行了展望。     

Modeling the Exchanges of Energy, Water, and Carbon Between Continents and the Atmosphere

Atmospheric general circulation models used for climate simulation and weather forecasting require the fluxes of radiation, heat, water vapor, and momentum across the land-atmosphere interface to be specified. These fluxes are calculated by submodels called land surface parameterizations. Over the last 20 years, these parameterizations have evolved from simple, unrealistic schemes into credible representations of the global soil-vegetation-atmosphere transfer system as advances in plant physiological and hydrological research, advances in satellite data interpretation, and the results of large-scale field experiments have been exploited. Some modern schemes incorporate biogeochemical and ecological knowledge and, when coupled with advanced climate and ocean models, will be capable of modeling the biological and physical responses of the Earth system to global change, for example, increasing atmospheric carbon dioxide.     

Detection and Characterization of the Cumulene Carbenes H2C5 and H2C6

Two cumulene carbenes, H2C5 and H2C6, were detected in a supersonic molecular beam by Fourier transform microwave spectroscopy. Their rotational and leading centrifugal distortion constants were determined with high accuracy, such that the entire radio spectrum can now be calculated. Like the known carbenes H2C3 and H2C4, both molecules have singlet electronic ground states and linear carbon-chain backbones. They can be produced in sufficiently high concentrations in the laboratory that their electronic spectra, expected to lie in the visible, should be readily detectable by laser spectroscopy. The microwave spectra of other, more exotic isomers may be detectable as well.     

The Current State of Solar Modeling

Data from the Global Oscillation Network Group (GONG) project and other helioseismic experiments provide a test for models of stellar interiors and for the thermodynamic and radiative properties, on which the models depend, of matter under the extreme conditions found in the sun. Current models are in agreement with the helioseismic inferences, which suggests, for example, that the disagreement between the predicted and observed fluxes of neutrinos from the sun is not caused by errors in the models. However, the GONG data reveal subtle errors in the models, such as an excess in sound speed just beneath the convection zone. These discrepancies indicate effects that have so far not been correctly accounted for; for example, it is plausible that the sound-speed differences reflect weak mixing in stellar interiors, of potential importance to the overall evolution of stars and ultimately to estimates of the age of the galaxy based on stellar evolution calculations.     

Effects of thyroxine administration on the growth and survival of pike silverside (Chirostoma estor) juveniles

The pike silverside has high aquaculture potential despite its slow growth. In this study, thyroxine (T₄) concentrations (0.13, 1.3 and 13 nM), a control with no hormonal supplement and a negative control containing 4.5 mM methimazole (MMI) were tested to evaluate the growth of this species. Juveniles (0.2 g) were exposed by immersion to these treatments for 8 h every second day for 120 days, and growth evaluations were performed monthly over the entire trial period. In addition, tissue samples from each treatment group were assayed for triiodothyronine (T₃) and deiodinase type 2 (D2) activity . The survival rates in all T₄ groups were high, and a significant increase in growth was observed (average of 58%). The MMI treatment caused an increase in mortality and a reduction in the final body weight compared with the control. T₄ administration did not affect the tissue levels of T₃, and it decreased muscular D2 activity only after 30 days of exposure. These results demonstrated that low concentrations of T₄ in the culture environment could improve the growth of this species without affecting tissue hormone levels. The technique may have useful applications for early‐stage aquaculture of this and other economically important species.     

Identification of the SP22 Sperm Protein in Santa Inês and Dorper Rams

The sperm membrane protein referred to as SP22 has been identified in different species and, at least in rats, is highly correlated with fertility. The goals of this study were to identify and to quantify the SP22 protein on spermatozoa from adult rams (Dorper and Santa Inês breeds), and to correlate its levels to morphological and kinematics parameters. SP22 on ram sperm was effectively quantified by both enzyme‐linked immunosorbent assay (ELISA) and fluorescein isothiocyanate immunostaining analysis and the two methods were significantly correlated (R² = 0.70). Clustering analysis of motility parameters obtained by computer‐assisted semen analysis system was used to establish that three distinct kinematic subpopulations with different vigour and progressiveness coexistent within ejaculate. While there were significant differences in the distribution of the three subpopulations in the rams, there was no significant correlation between the proportion of each subpopulation in the rams and the SP22 levels. Quantification of SP22 immunostaining intensity was not correlated with any of the sperm parameters. However, SP22 levels obtained by ELISA were negatively correlated with morphological abnormalities and positively correlated with membrane integrity (three variable R² = 0.47). Future breeding studies are now needed to validate that this protein is a biomarker of fertility in this species.     

High Periconceptional Protein Intake Modifies Uterine and Embryonic Relationships Increasing Early Pregnancy Losses and Embryo Growth Retardation in Sheep

The effects of supplemented protein level (PL) during the periconceptional period and their interaction with body condition were evaluated in sheep. Multiparous Rambouillet ewes (n = 12) received two PL of rumen undegradable protein (UIP) during a 30‐day pre‐mating and 15‐day post‐mating period: low [LPL, 24% crude protein (CP), 14 g UIP and 36 g/CP animal/day] and high [HPL, 44% CP, 30 g UIP and 50 g/CP animal/day]. While ovulation rate (OR) did not differ between treatments (1.6 ± 0.5, mean ± SEM), a lower fertility rate, a decreased embryo number and a reduced uterine pH (UpH) was observed in the HPL group (p < 0.05), irrespective of BC. Luteal tissue weight, volume and progesterone secretion did not differ among treatments. Sheep with lower UpH also had lower conceptus weight (Cwt; p < 0.05, r = 0.65) and conceptuses with lower mass tended to secrete less INF‐τ and IGF‐1, and the correspondent endometrial explants had a higher basal PGF_2α release. Current study indicates that high protein diets during the periconceptional period in sheep modify uterine and embryonic relationships, increasing early pregnancy losses and inducing embryo growth retardation. Surviving embryos were affected by weight reductions, which could compromise later foetal growth and birth weight. Results evidence the key role of a balanced diet in reproductive success and indicate that the quality and nutrient composition of the maternal diet are essential for an adequate establishment of pregnancy, having paramount effects on the interplay of the embryo and the uterus.