Bi‐parental vs. cooperative breeding in a passerine: fitness‐maximizing strategies of males in response to risk of extra‐pair paternity?

In socially monogamous species, males that risk cuckoldry more than others might gain inclusive fitness by yielding paternity to relatives. We tested this prediction in the Tibetan ground tit Pseudopodoces humilis , an unusual facultative cooperative breeder wherein most helpers (87% males) join a mated pair shortly before clutch completion. Extra-pair paternity among bi-parental broods occurred less often (26% of broods, 9% of young) compared with cooperative broods (68%, 25%). In the former, most extra-pair sires (88%) were pair breeders unrelated to the cuckolded males, whereas in the latter, sires (87%) were mainly helpers related to the dominant males. Brood productivity did not differ between the bi-parental and cooperative breeders, but helpers' partitioning over group paternity reduced the realized reproductive success of helped males. After taking inclusive fitness into account, however, there was no difference in success of dominant males between the two social systems. One possible explanation for the differences in the rates of cuckoldry in the two systems was body size, because pair-bond males in bi-parental situations were significantly larger than those in cooperative ones. We propose two alternative strategies for males to maximize fitness: breed as a pair if large to avoid cuckoldry from helpers, or breed cooperatively if small but compromise some paternity to relatives. Our results provide an unusual route to the incidence of cooperative groups, based on constraints imposed by low competitive ability of breeding males rather than some external ecological or demographic factors.     

4种山药多糖的体外发酵特性比较研究

采用体外发酵技术评价分段醇沉得到的4个山药多糖对宁乡猪盲肠食糜体外发酵特性和发酵产物的影响,探讨其用作动物功能性营养调控剂的可行性.乙醇终浓度(%)分别为30、45、60和75时沉淀得到4个山药多糖,用硫酸蒽酮法测得其总多糖含量(%)分别为45.85、56.24、90.91和13.87.选用正常饲喂的肥育宁乡猪,处死后无菌取盲肠食糜作为接种物,分别以4个山药多糖和葡萄糖为底物进行体外发酵.于不同发酵时间点记录产气量,48 h后检测发酵液pH值、NH3和SCFA含量.结果表明,75%醇沉多糖发酵动力学参数最优,并极显著优于葡萄糖组(P<0.01);45%、60%醇沉多糖和葡萄糖组pH值最低,60%、75%醇沉多糖和葡萄糖组的NH3含量最低;葡萄糖组的乙酸、丁酸和异丁酸含量均显著高于其它处理组(P<0.05),60%醇沉多糖组的丙酸含量稍高于、丁酸和异丁酸含量略低于其它3个多糖组.丁酸和异丁酸含量与pH值和NH3含量呈显著相关.提示60%和75%醇沉山药多糖是2种理想的可被宁乡猪盲肠微生物利用的碳源,并可改变微生物产生的SCFA含量与组成.     

双波长法测定二元混合体系中戊糖的含量

目的:针对单波长法在测定己糖和戊糖的混合体系中戊糖含量时出现较大的误差,提出了等吸收双波长法测定二元混合体系中戊糖的含量.方法:通过对己糖(葡萄糖)和戊糖(木糖)的不同含量(5-150μg/体系)与显色剂反应产物在不同波长(500,～700nm)条件下吸光曲线以及显色剂本身吸光曲线进行综合考虑,确定双波长,并对单双波长法测定同样样品的回收率进行了比较分析.结果:确定的测定波长为670nm,参比波长为580nm,双波长法建立的标准曲线方程为:Y=0.0056x-0.0123(y为两个波长下吸光度的差值,x为木糖的含量(μg)).R2=0.9995,线性范围为5-30μg/体系.单波长法对标样和试样的平均回收率分别为116%±15%和89%±13%;双波长法对标样和试样的平均回收率为104%±4%和95%±11%.结论:与单波长和一些其他方法相比,双波长法测定混合体系中戊糖含量较为简便易行且可以提高准确度.     

靶向ASGPR的反义核酸与抗HBV药物联合用药的体外抗HBV作用

研究以宿主基因ASGPR为靶的反义核酸与抗乙肝病毒(hepatitis B virus,HBV)药物联合应用的抗-HBV作用,为HBV感染的联合治疗和用药提供新的思路。以HepG2.2.15细胞为靶细胞,脂质体为载体将靶向ASGPR的硫代反义寡核苷酸(ASODN)转染至HepG2.2.15细胞中,6h后加入抗病毒药拉米夫定(3TC)或阿地福韦(ADV),72h后收集细胞培养液,采用酶联免疫法及荧光定量PCR法测定ASODN与抗-HBV药物联合应用后对细胞培养液中HBsAg、HBeAg及细胞分泌HBV DNA的抑制作用。采用金正均Q值法对数据进行分析。拉米夫定(3TC)和阿地福韦(ADV)分别与ASODN联用对HBsAg的抑制呈相加或协同作用。随着ADV浓度的增加,两药的协同作用下降。3TC与ASODN联用对HBeAg的抑制呈拮抗、相加和协同作用,其拮抗作用随着3TC浓度的增加逐渐减弱。ADV与ASODN联用对HBeAg的抑制只呈相加作用。3TC和ADV分别与ASODN联用对HBV DNA的抑制均表现为相加作用或协同作用,取ADV0.5μmol/L与取ASODN0.2μmol/L联用时对HBV DNA的抑制率可提高到72.6%。ASODN在一定条件下分别与3TC及ADV联用有相加或协同抗HBsAg、HBeAg及HBV DNA的表达,尤以抗HBsAg作用显著增强。     

Effects of light on cyanide‐resistant respiration and alternative oxidase function in Arabidopsis seedlings

Mitochondrial alternative oxidase (AOX), the unique respiratory terminal oxidase in plants, catalyzes the energy wasteful cyanide (CN)‐resistant respiration and plays a role in optimizing photosynthesis. Although it has been demonstrated that leaf AOX is upregulated after illumination, the in vivo mechanism of AOX upregulation by light and its physiological significance are still unknown. In this report, red light and blue light‐induced AOX (especially AOX1a) expressions were characterized. Phytochromes, phototropins and cryptochromes, all these photoreceptors mediate the light‐response of AOX1a gene. When aox1a mutant seedlings were grown under a high‐light (HL) condition, photobleaching was more evident in the mutant than the wild‐type plants. More reactive oxygen species (ROS) accumulation and inefficient dissipation of chloroplast reducing‐equivalents in aox1a mutant may account for its worse adaptation to HL stress. When etiolated seedlings were exposed to illumination for 4 h, chlorophyll accumulation was largely delayed in aox1a plants. We first suggest that more reduction of the photosynthetic electron transport chain and more accumulation of reducing‐equivalents in the mutant during de‐etiolation might be the main reasons.     

三种苦瓜多糖的体外发酵特性比较研究

采用体外发酵技术评价分段醇沉提取的3种苦瓜多糖(MCP1、MCP2和MCP3,乙醇终浓度分别为45%、60%和75%)对三元猪盲肠食糜的发酵特性和发酵产物的影响。于不同发酵时间点记录产气量,48 h后检测发酵液pH值、NH3和短链脂肪酸(SCFA)含量。结果表明,MCP1和MCP2发酵动力学参数最优,显著优于葡萄糖和空白对照组(P0.05);MCP2和葡萄糖组pH值最低,MCP1和葡萄糖组的NH3含量最低;葡萄糖组的丙酸、异丁酸和SCFA总量显著高于其它各组(P0.05);MCP2的乙酸、异丁酸和SCFA总量显著高于其它多糖组(P0.05)。结果提示,MCP1和MCP2是2种理想的可被盲肠微生物利用的碳源,并可改变微生物发酵产生的SCFA含量与组成。     

中等强度跑台运动预防去卵巢大鼠骨质疏松

目的观察中等强度跑台运动对去卵巢大鼠骨质疏松的预防作用。方法将30只3月龄未经产雌性SD大鼠随机分为假手术、去卵巢静止和去卵巢运动三个组。去卵巢运动组每周进行4次时间45min、速度18m/min、坡度5°的跑台训练。实验结束时,检测血清雌二醇（E2）、碱性磷酸酶（ALP）、抗酒石酸酸性磷酸酶（TRAP）和骨钙素（BGP）水平以及右侧游离股骨和胫骨的骨密度（BMD）和骨矿物含量（BMC）;同时观察左侧股骨远端和胫骨近端组织形态学变化。结果与假手术组比较,去卵巢静止组大鼠血清ALP活性和BGP含量显著升高,血清TRAP活性和E2含量显著下降,股骨近段和远端以及胫骨近端BMD和BMC显著下降,股骨远端和胫骨近端骨小梁断裂增加、数目减少;与去卵巢静止组比较,去卵巢运动组大鼠血清E2和BGP含量显著上升,股骨三个部位以及胫骨近端BMD和BMC显著增加,股骨远端和胫骨近端骨小梁断裂减少、数目增加。结论中等强度跑台运动能增加去卵巢大鼠血清E2和BGP含量,改善去卵巢大鼠骨组织学结构。     

不同生存条件下东方田鼠肝脏基因表达谱分析

目的比较实验室条件下饲养的东方田鼠和野外捕捉东方田鼠肝脏的基因表达差异,寻找可能参与肝脏病变的关键基因。方法以实验室条件饲养的东方田鼠和野外捕捉东方田鼠为研究对象,分别抽提RNA,逆转录成cDNA,体外转录为cRNA并进行片段化;利用表达谱芯片分别进行杂交,扫描后筛选差异基因,并应用real-time PCR方法对部分基因的表达水平进行进一步测定,验证芯片数据的结果。结果实验室饲养东方田鼠肝组织与野外捕捉东方田鼠相比,共有99个基因和41个EST差异表达。其中参与机体代谢的基因占主导,约占35.4%;其次为参与信号通路的基因,约占24.2%;参与细胞周期和免疫的基因分别占6.1%和3.0%。结论利用基因表达谱芯片初步筛选了可能参与东方田鼠脂肪肝形成过程的基因,发现机体代谢通路的基因占主导,肝脏中细胞色素家族基因表达差异明显。     

成体干细胞临床应用研究

干细胞是一类具有自我更新能力和多向分化潜能的细胞,其处于未定向分化状态并具有增殖能力.成体干细胞多向分化潜能,安全性好而在临床应用报道逐渐增多,本文总结了1998-2008年的成体干细胞临床应用的实例报道,以期为临床科研人员和患者提供信息支持.     

Physical and chemical cues affect oviposition by Neoleucinodes elegantalis

Recognition and acceptance of a suitable host plant by phytophagous insects requires the integration of visual, physical and chemical cues. The present study investigates the host cues that a specialist insect integrates to optimize oviposition decisions and whether these cues are weighted in a specific way. The study also determines whether the tomato fruit borer Neoleucinodes elegantalis (Guenée) (Lepidoptera: Crambidae), an important pest on Solanaceae in Brazil, shows a preference for oviposition sites that differ in physical and/or chemical cues. When styrofoam balls are provided as artificial fruits, N. elegantalis deposit significantly more eggs on rough artificial fruits than on smooth ones. Hexane fruit extracts applied to the artificial fruits stimulate female oviposition strongly. Physical and chemical cues also affect the oviposition of females when offered together. Furthermore, certain parts of the artificial fruits are prefered, irrespective of the presence of chemical cues. Both physical and chemical cues affect oviposition decisions; hence, the fruit borer relies on cues of different sensory modalities.