Sex differences in morphine-induced behavioral sensitization and social behaviors in ICR mice

Gender and genetic strain are two prominent variants that influence drug abuse. Although certain sexrelated behavioral responses have been previously characterized in ICR mice, little is known about the effects of sex on morphine-induced behavioral responses in this outbred strain. Therefore, in this study, we investigated the sex differences of morphine-induced locomotion, anxiety-like and social behaviors in ICR mice. After morphine or saline exposure for four consecutive days(twice daily), increased locomotion, more time spent in the central area, as well as attenuated rearing and self-grooming behaviors were found in morphine-treated females in an open field; no differences were found in locomotion and the time spent in the central area between male and female controls. When interacting with the samesex individuals, female controls were engaged in more social investigation, following, body contacting and self-grooming behaviors than controls; morphine exposure reduced contacting and self-grooming behaviors in females; in contrast, these effects were not found in males. These results indicate that female ICR mice are more prosocial and are more susceptible to morphine exposure than males.     

木聚糖酶基因研究进展

半纤维素分解微生物在自然界碳素循环中起着重要作用,半纤维素是植物多糖的重要成分之一。木聚糖则是半纤维素的主要成分。木聚糖酶(EC3.2.1.8)可催化木聚糖的水解,在各种各样的生物体里都发现有木聚糖酶,如细菌、放线菌、真菌。在过去几十年里,有超过100个木聚糖酶基因被克隆进同源或异源宿主中,其目的是为了超表达木聚糖酶和改变它们的特性以适应商业应用。木聚糖酶的应用极其广泛,可用于生物转化、造纸、食品、饲料、能源、纺织等行业。尤其是迫切的环境问题将进一步促进木聚糖酶研究的开展。     

Positive Interactions： Crucial Organizers in a Plant Community

For more than a century, ecologists have concentrated on competition as a crucial process for community organization. However, more recent experimental investigations have uncovered the striking Influence of positive Interactions on the organization of plant communities. Complex combinations of competition and positive interactions operating simultaneously among plant species seem to be widespread In nature. In the present paper, we reviewed the mechanism and ecological importance of positive Interactions In plant communities, emphasizing the certainties and uncertainties that have made It an attractive area of research. Positive Interactions, or facilitation, occur when one species enhances the survival, growth, or richness of another. The Importance of facilitation in plant organization increases with ablotlc stress and the relative Importance of competition decreases. Only by combining plant interactions and the many fields of biology can we fully understand how and when the positive Interactions occur.     

Host plant mediation of diapause induction in the cabbage beetle, Colaphellus bowringi Baly （Coleoptera： Chrysomelidae）

The cabbage beetle, Colaphellus bowringiBaly （Coleoptera： Chrysomelidae）, is a serious pest of crucifers in China, undergoing an imaginal summer and winter diapause in the soil. The effects of host plants on diapause incidence were tested in the beetle. The ratio of adults entering diapause was significantly low when they fed on the mature leaves of Chinese cabbage Shanghaiqin （Brassica chinesis var communis） than those feeding on Chinese cabbage Suzhouqin （Brassica chinesis var communis）, radish （Raphanus sativus var longipinnatus） and stem mustard （Brassicajuncea vat tumida） at 25℃ combined with 13：11 （L： D） h. Fewer adults entered diapause on young leaves compared to physiologically aged and mature radish leaves at 25℃ combined with 13：11 （L： D） h. The effect of host plant species on diapause induction was also evident under continuously dark rearing conditions or at different photoperiods. These experimental results demonstrate that host plant mediation of diapause induction exists in the cabbage beetle. However, at temperatures ≤20℃ or photoperiods of 16：8 （L： D） h combined with 25℃, all individuals entered diapause regardless of the host plants, indicating that the effects of host plants on diapause induction could be expressed only within a limited range of temperatures and photoperiods.     

Differential responses to feeding by the tomato/potato psyllid between two tomato cultivars and their implications in establishment of injury levels and potential of damaged plant recovery

An invasive new biotype of the tomato/potato psyllid （Bactericera [Paratrioza] cockerelli [Sulc.]） （Homoptera： Psyllidae） recently has caused losses exceeding 50% on fresh market tomatoes in western North America. Despite these extensive losses, little is known regarding the threshold levels at which populations must be suppressed in order to prevent economic losses. A series of experiments were therefore designed using combinations of two common tomato cultivars （QualiT 21 and Yellow Pear）, five pest-densities （0, 20, 30, 40 and 50 nymphs/plant）, and three feeding-duration （5 days, 10 days, and lifetime） treatments to test the relative importance of pest density, feeding period, and cumulative psyllid-days to establish economic threshold levels for psyllids. The cultivars differed considerably in their response to the toxin injected by the psyllid nymphs. ‘Yellow Pear＇ plants could recover from feeding by up to 40 nymphs for as long as 10 d, whereas ‘QualiT 21＇ plants were irreparably damaged by densities of 20 nymphs feeding for only 5 days. On ‘Yellow Pear＇, all plant measurements such as the number of yellow leaves and plant height were significantly better correlated with cumulative psyUid-days than with either pest density or feeding duration. On ‘QualiT 21 ＇, all plant measurements other than the number of yellow leaflets and leaves were significantly better correlated with pest density than with feeding duration or cumulative psyUid-days, and pest density was a better predictor of psyUid damage. Potential reasons for the variable responses between cultivars and the implications for psyllid sampling and integrated pest management are discussed.