生后早期听觉剥夺、经验改变大鼠听皮层NMDA受体NR2B蛋白表达

应用蛋白质印迹检测技术,研究早期听觉剥夺、经验对大鼠听皮层NMDA受体NR2B蛋白表达的影响.结果表明,听觉剥夺使生后14天龄组和28天龄组动物听皮层NR2B蛋白表达水平明显下降(P<0.05,P<0.01),听觉剥夺7天后再给予纯音暴露则又使NR2B表达水平明显提高(P<0.05),呈现双向调节趋势.听觉剥夺和纯音暴露对生后42天龄组大鼠听皮层NR2B表达不再产生明显调节作用(P>0.05).结果提示,在大鼠生后发育关键期,听觉剥夺、经验可改变听皮层NMDA受体NR2B蛋白表达水平.研究结果为研究感觉功能发育可塑性的机制提供了重要实验资料.     

Why are males more attractive after brood care? Proximate causes of enhanced sex pheromone emission in a burying beetle

Recent studies demonstrate that pheromones can be costly to produce and emit and, therefore, the types and quantities that they express are likely to covary with individual condition. Previous experiments reveal that, when given the opportunity to breed and care for young, male burying beetles Nicrophorus vespilloides go on to produce a higher amount of their sex pheromone and attract more females than control males that do not exhibit parental care. This finding is surprising because parental care is usually assumed to be energetically costly, reducing the future capacity to invest in sexual signalling. However, burying beetles reproduce on dead vertebrates and the carrion meal might enable males to acquire resources that can subsequently be allocated to pheromone signalling. Alternatively, males might accumulate pheromone precursors because they do not emit their sex pheromone during brood care. To shed light on the mechanisms of enhanced pheromone emission after brood care, in the present study, we test the effect of diet quality, social condition during care (biparental versus uniparental care) and an experimentally enforced calling pause on subsequent male pheromone emission, body weight and energy storage components. The experimentally enforced calling pause and social condition during brood care demonstrate no impact on pheromone quantity. However, the results of the present study suggest that the vertebrate carrion meal during brood care partly explains enhanced pheromone release after care. Unravelling the biosynthetic pathways of the pheromone components and analyzing the impact of potential microbial symbionts on pheromone production represents a fruitful avenue for future research.     

Predatory risk increased due to egg‐brooding in Armadillidium vulgare (Isopoda: Oniscidea)

Cost of reproduction is associated with a reduction in subsequent survival or future breeding success. A decrease in survival rate of parents during or after reproduction reduces the probability of their future reproduction. However, few studies have demonstrated such survival costs to parents. Females of Armadillidium vulgare hold their eggs in a marsupium and brood these until the young hatch. Caring for eggs in a marsupium seems to place a large burden on brooding females, and it restricts their predator avoidance behaviour. As such, costs of care may increase the mortality rates of brooding females. To reveal the costs of parental care, we examined the effects of egg brooding on behaviour and predation risk. Egg‐brooding females decreased speed of locomotion and rolling duration, and were killed by predators at a higher rate. Our results indicate that egg brooding in A. vulgare has costs in the form of predation risk.     

9. LIST OF MEMBERS (as at date of publication)

We studied the breeding ecology of the Chestnut-backed Sparrowlark Eremopterix leucotis over three years between 2008 and 2010. The breeding season was bimodal with a main peak in laying in autumn (March–April) and another smaller peak in spring (September–October). Nest microhabitat analyses showed they prefer nesting in open areas with lots of bare ground (median 67.5%). Nest entrance directions were biased towards the south (mean vector (µ) = 186.44°). The majority of nests (78.2%) had an apron at the nest entrance. The mean clutch size was 1.88 but there was geographic variation in clutch size between northern and southern races of the species. The mean incubation and nestling periods were 10.33 d (range 10–11 d) and 9.20 d (range 8–10 d), respectively. The results suggest that parental contributions during incubation are almost equal, but females made significantly more food deliveries during the nestling period compared to males. The diet of nestlings comprised mainly of invertebrates (50.2%), seeds (34.4%) and unidentified food items (15.4%). Breeding success was low, averaging 16.1% (range 8.1–20.6%), and the average number of fledged young per pair was 0.36 ± 0.71. Replacement broods were common and we also recorded repeat brooding attempts.     

The role of DNA polymerase I-associated 5'-exonuclease in replication of coliphage M13 replicative-form DNA.

The conversion of both parental- and progeny-nascent open circular M13 RF DNA into covalently closed RF I is drastically reduced in an $\text{E. coli}$ mutant deficient in the 5′ → 3′ exonuclease associated with DNA polymerase I. The nascent progeny RF DNA also contains a significant proportion of fragments of smaller than unit length.     

城市公园的环境–活动游憩机会谱模型研究——以广州珠江公园为例

城市公园游憩体验的研究对于解决多样化的游憩需求与有限的游憩资源之间的矛盾具有重要意义。将游憩机会谱理论应用于城市公园游憩体验质量改善,提出环境–活动游憩机会谱模型（E-A ROS）。以广州珠江公园为例,采用问卷调查法和SPSS统计分析法,从物质、社会、管理3个方面构建珠江公园环境质量评价的指标体系和指标量化方法,从人口统计学特征、行为特征和行为偏好3个方面进行活动因子研究,探讨珠江公园使用者活动规律,构建珠江公园游憩机会谱。从而为城市公园环境–活动游憩机会谱模型的应用提供了详细的操作指引。     

Leaf malformation during early development in Sorghum. Evidence for an embryonic developmental window

Salt adaptation was induced in two successive generations of Sorghum bicolor , and the germination of their seeds was compared. When germinated in the absence of NaCl, the progeny of adapted plants displayed a specific malformation at the first two leaves, which was never observed in progeny of control plants. The frequency of leaf malformation was enhanced in progeny of the second generation of adapted plants, indicating a cumulative influence of salt adaptation. When germinated in the presence of 75 m M NaCl, seedlings from seeds of salt-adapted plants never displayed the leaf malformation, whereas it was observed on seedlings from seeds of control plants germinated in the presence of 75 m M NaCl. The occurrence of leaf malformation was analyzed for progeny of 20 salt-adapted plants germinated in the absence of NaCl. The link with the reproductive characters of the parents indicates a strong parental control on the expression of the leaf malformation. A comparison with previous data relative to the leaf malformation in Sorghum suggests the existence of a developmental window which 'opens'during embryo morphogenesis. This enables the imprinting of the embryo by the parent's physiological environment. This conclusion is related to other data describing a long-term maternal influence in plants.     

Signalling of information that is neither cryptic nor private

It is commonly assumed that in order for animal signals to be advantageous, the information being signalled could not have been obtained otherwise, and is therefore ‘cryptic’ or ‘private’. Here, we suggest a scenario in which individuals can gain an advantage by signalling ‘public’ information that is neither cryptic nor private. In that scenario, signalling increases the efficiency with which that ‘public’ information is transmitted. We formalize our idea with a game in which offspring can signal their condition to their parents. Specifically, we consider a resource‐strapped parent who can only invest in one of its two offspring, and we allow offspring the chance to influence parental investment through a signal. A parent in the game seeks to invest in the higher‐quality offspring, which it could identify either through a publicly available cue, such as body size, or by relying on a signal provided by the offspring. We find that if the signal can convey information about offspring quality more efficiently than cues, then signalling of condition between offspring and parents can be favoured by selection, even though parents could potentially have acquired the same information from the cue. Our results suggest that the biological function of signals may be broader than currently considered, and provide a scenario where low cost signalling can be favoured. More generally, efficiency benefits could explain signalling across a range of biological and economic scenarios.