Evidence for Sex-Biased Behavioral Maternal Investment in the Gray Mouse Lemur (Microcebus murinus)

To study sex-differential allocation of maternal behavior in Microcebus murinus, I recorded behavioral patterns on 21 litters from parturition to the weaning period. After a pregnancy of 61.5 ± 0.9 days, females may produce from one to four young per litter. Litters were weaned in 40 days by mothers. Behavioral observations at the beginning of the nocturnal activity period demonstrated that close contacts between mothers and infants were more frequent in multiparous mothers than in primiparous ones (p < .01). Time in close contact with offspring aged >15 days old compared to contacts with neonates is significantly lower only in single-sex litters and is more marked for all-female litters (p < .01). Mother's approaches toward mixed litters or all-male litters were always significantly greater than approaches toward all-female litters (p = .04). However, mother's approaches within mixed sex litters were not biased toward either sex (p = .7). Males in a litter may be interpreted as a stimulator of maternal behavior. Similarly, using retrieving tests of 15-min duration, a significant maternal preference for male neonates is evident. Latency to first retrieval is significantly shorter in multiparous females than in primiparous ones (p < .05) independent of size and sex ratio of the litter. For multiparous females only, male neonates were chosen first for retrieval more often than females (p < .05). Finally, the calls of young played a stimulator effect on maternal retrieving (p < .001). Accordingly multiparous mothers exhibit more interest in their young, which appears to be biased toward male neonates.     

弱光胁迫对不同生育期番茄光合特性的影响

以耐弱光番茄品系02S02、02S32和不耐弱光番茄品系02S52、02S57为材料,以普通塑料大棚光照环境为对照(晴天9:00-11:00平均光强约为800 μmol·m^-2·s^-1),普通塑料大棚上覆盖一层黑色遮阳网模拟弱光环境(光强约为对照的50%),研究弱光对4个番茄品系苗期、开花座果期、果实膨大期光合特性的影响.结果表明：弱光环境下,4个番茄品系叶片光合速率在低光强下略有增加,超过此光强后大幅下降,不同品系在不同生育期的变化趋势一致,但变化幅度不同;叶片光补偿点和暗呼吸速率随发育进程逐渐降低,耐弱光品系的降幅均大于不耐弱光品系;叶片光饱和点、最大光合速率和表观量子效率在不同生育期均有所降低,但变化幅度不同,且与品系的弱光耐受性无一致性关系.     

Recovering and reamplifying of the differentially expressed cDNA bands isolated from mRNA differential display

Methods for retrieving and reamplifying the differentially expressed cDNA bands have been modified. Direct reamplification of differentially expressed bands after cutting from a polyacrylamide gel (PAG) followed by a simple rinse and crush step has proved to be more convenient and effective than the traditional glycogen-precipitation method. Combination of 30 cycles of differential display (DD) polymerase chain reaction (PCR) and 20 cycles of standard PCR reaction also yielded higher reamplification rates.