印度地鼠的性成熟和窝仔数

为有效地进行有害脊椎动物的控制 ,研究了栖息于巴基斯坦Punjab中部的 348只印度地鼠的繁殖模式。在所捕捉到的 10 7雄鼠和 2 4 1只雌鼠中 ,分别有 75只和 179只是性成熟的个体。性比偏雌。使用被捕个体标本的体重和体长作为指标 ,发现最小的性成熟的雄性个体体重为 70 - 89g ,体长 13 1- 14 0cm ;一窝仔里面的平均胚胎数为 2 74± 0 15 (范围 ,1- 5 ) ,而平均胎斑数为 4 2 9± 0 19(1- 11) .体重似乎对窝仔数有显著影响 ,而体长和估计的年龄对窝仔数没影响。当老鼠繁殖不活跃和不繁殖时 ,控制害兽最有效     

阿拉善黄鼠的生命表及繁殖

将采自野生种群的阿拉善黄鼠(Spermophilus dauricus alaschanicus Buechner)( 下称黄鼠)样本划分为8个年龄间隔,然后编制生命表。结果表明,黄鼠的平均死亡率(qx)为0.7512(♂)和0．6222(♀),平均寿命为1.3311年(♂)和1.1073年(♀)。0-l岁龄黄鼠的期望寿命(ex)为0.8311年(♂)和1.1073年(♀)。世代净增殖率(R_o)每代为l.7327。种群内禀增长率(瞬时)(r_m)为0.1433,世代平均时间(T)为3.8346年,周限增长率(r)为1.1541/年。     

合成生物制造2022

本文对2022年《生物工程学报》发表的与合成生物制造相关的综述和研究论文进行了评述,重点讨论了DNA测序、DNA合成、DNA编辑、基因表达调控和数学细胞模型等底层技术,酶的设计、改造和应用技术,化学品生物催化、氨基酸及其衍生物、有机酸、天然化合物、抗生素与活性肽、功能多糖、功能蛋白质等重要产品的生物制造技术,一碳化合物和生物质原料利用技术以及合成微生物组技术,以帮助读者从一个侧面了解合成生物制造相关技术和产业的发展情况。     

Ubiquitin-proteasome pathway modulates mouse oocyte meiotic maturation and fertilization via regulation of MAPK cascade and cyclin B1 degradation

Degradation of proteins mediated by ubiquitin-proteasome pathway (UPP) plays important roles in the regulation of eukaryotic cell cycle. In this study, the functional roles and regulatory mechanisms of UPP in mouse oocyte meiotic maturation, fertilization, and early embryonic cleavage were studied by drug-treatment, Western blot, antibody microinjection, and confocal microscopy. The meiotic resumption of both cumulus-enclosed oocytes and denuded oocytes was stimulated by two potent, reversible, and cell-permeable proteasome inhibitors, ALLN and MG-132. The metaphase I spindle assembly was prevented, and the distribution of ubiquitin, cyclin B1, and polo-like kinase 1 (Plk1) was also distorted. When UPP was inhibited, mitogen-activated protein kinase (MAPK)/p90rsk phosphorylation was not affected, but the cyclin B1 degradation that occurs during normal metaphase-anaphase transition was not observed. During oocyte activation, the emission of second polar body (PB2) and the pronuclear formation were inhibited by ALLN or MG-132. In oocytes microinjected with ubiquitin antibodies, PB2 emission and pronuclear formation were also inhibited after in vitro fertilization. The expression of cyclin B1 and the phosphorylation of MAPK/p90rsk could still be detected in ALLN or MG-132-treated oocytes even at 8 h after parthenogenetic activation or insemination, which may account for the inhibition of PB2 emission and pronuclear formation. We also for the first time investigated the subcellular localization of ubiquitin protein at different stages of oocyte and early embryo development. Ubiquitin protein was accumulated in the germinal vesicle (GV), the region between the separating homologous chromosomes, the midbody, the pronuclei, and the region between the separating sister chromatids. In conclusion, our results suggest that the UPP plays important roles in oocyte meiosis resumption, spindle assembly, polar body emission, and pronuclear formation, probably by regulating cyclin B1 degradation and MAPK/p90rsk phosphorylation.     

Influence of diet and photoperiod on development and reproduction of European populations of Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae)

The current study examines the effect of photoperiod (16:08 or 12:12 h L:D) and diet (eggs of Ephestia kuehniella Zeller (Lepidoptera: Phycitidae) or the pea aphid Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae)) on the development and reproduction of the multicoloured Asian lady beetle Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae). A long-term laboratory population of H. axyridis (since 1998) and a melanic and non-melanic population originating from field collected individuals of H. axyridis in Belgium were used in this study. Long day conditions (16 h photoperiod) shortened development of the field populations with 2–3 days when compared with short day conditions (12 h photoperiod). Oviposition in the field populations was delayed by 1–3 months when reared at a 12 h photoperiod. Dissections indicated that the females were in reproductive diapause. As compared with live pea aphids, a diet consisting of E. kuehniella eggs yielded heavier adult body weights (up to 12%) and increased the number of egg laying days (by 45–169%) for both field populations at a 16 h photoperiod and lengthened adult life span (by 45–92%) under both light regimens. The morph types differed in their response to the foods offered in terms of developmental rate, pre-oviposition period and number of oviposition days. The laboratory and field strains responded differentially to regimens of food and photoperiod. The study indicated a greater nutritional plasticity of the non-melanic morphs which may offer them a competitive advantage that may in part explain the predominance of non-melanic morphs in newly colonized areas.     

Beyond directed evolution: Darwinian selection as a tool for synthetic biology

Synthetic biology is an engineering approach that seeks to design and construct new biological parts, devices and systems, as well as to re-design existing components. However, rationally designed synthetic circuits may not work as expected due to the context-dependence of biological parts. Darwinian selection, the main mechanism through which evolution works, is a major force in creating biodiversity and may be a powerful tool for synthetic biology. This article reviews selection-based techniques and proposes strict Darwinian selection as an alternative approach for the identification and characterization of parts. Additionally, a strategy for fine-tuning of relatively complex circuits by coupling them to a master standard circuit is discussed.     

LOCOMOTOR PERFORMANCE AT LOW TEMPERATURE AND THE EVOLUTION OF NOCTURNALITY IN GECKOS

Nocturnal geckos are active at body temperatures 10–35°C below the thermal optima for maximum rate of aerobic metabolism of diurnal lizards. Therefore, given ancestral (diurnal) lizard physiology, nocturnality causes a substantial thermal handicap in locomotor performance. In prior studies, we hypothesized that a low minimum cost of locomotion (C_min) in geckos was an adaptation that increased locomotor endurance capacity at low, nocturnal temperatures. However, C_min is only part of an integrated system that, in conjunction with the maximum rate of oxygen consumption, sets the maximum speed that can be sustained aerobically (termed the maximum aerobic speed or MAS). We conducted the first phylogenetic analysis of MAS and lizards and found that the greatest changes in MAS, C_min and (at activity temperatures) in the evolutionary history of lizards all coincided with the evolution of nocturnality in geckos. Geckos active at 15–25°C did not become optimized for nocturnal temperatures, or fully offset the thermal effects of nocturnality by evolving maximal rates of oxygen consumption comparable to diurnal lizards active at 35°C. Geckos did evolve MAS twice that of diurnal lizards running at low temperatures by evolving a remarkably low C_min. Allometric analysis and phylogenetically independent contrasts of , C_min, and MAS indicate a 72% evolutionary decrease in , (at activity temperatures) and a 50% evolutionary decrease in C_min concordant with the evolution of nocturnality in geckos. Experimental measurements show that decreased C_min in six species of gecko increased MAS by 50–120% compared to diurnal lizards at low temperatures. Thus, geckos sufficiently overcame the near paralyzing effects of nocturnal temperatures, but only offset about 50% of the decrease in MAS resulting from the low maximum rate of oxygen consumption. Although the nocturnal environment remains severely suboptimal, the evolution of a low cost of locomotion in the ancestor of geckos was highly adaptive for nocturnality. We also present a generalized approach to ecophysiological evolution that integrates phylogeny with the causal relationships among environment, physiology, and performance capacity. With respect to a clade, two hypotheses are central to our integrative approach: (1) a change of an environmental variable (e.g., temperature) causes a performance handicap; and (2) evolution of a physiological variable (e.g., minimum cost of locomotion [C_min]) increases performance in the derived environment. To test the hypothesis that evolution of a physiological variable is adaptive in nature, we suggest determining if individuals in nature perform at levels exceeding the performance capacity of their hypothetical ancestors and if this additional performance capacity is due to the evolution of the physiological variable in question.     

保护行为学: 正在兴起的保护生物学分支学科

过去的30年里, 人们利用动物行为的进化生物学方法来解决保护实践中遇到的问题, 行为学、行为生态学与保护生物学相结合, 产生了保护生物学的一个新分支学科--保护行为学。保护行为学的研究目的是: 从物种保护实践中发现环境对动物行为的影响以及行为的生态适应性, 并把动物行为学和行为生态学理论应用到物种保护实践中, 从而促进物种保护工作。目前全球有10%的物种濒临灭绝, 生物多样性保护日趋紧迫, 保护行为学的诞生为行为学和保护生物学研究带来了新的机遇, 也表明行为学家和保护生物学家正在担负起挽救濒危物种的使命。不久的将来, 保护行为学及其相关学科将更加繁荣。     

John Kendrew and myoglobin: Protein structure determination in the 1950s

The essay reviews John Kendrew's pioneering work on the structure of myoglobin for which he shared the Nobel Prize for Chemistry in 1962. It reconstructs the status of protein X‐ray crystallography at the time Kendrew entered the field in 1945, after distinctive service in operational research during the war. It reflects on the choice of sperm whale myoglobin as research material. In particular, it highlights Kendrew's early use of digital electronic computers for crystallographic computations and the marshaling of other tools and approaches that made it possible to solve the structure at increasing resolution. The essay further discusses the role of models in structure resolution and their broader reception. It ends by briefly reviewing Kendrew's other contributions in the formation and institutionalization of molecular biology.     

Biology of Ixodes (Pholeoixodes) hexagonus under laboratory conditions Part II. Effect of mating on feeding and fecundity of females

The effect of mating on the feeding and fecundity ofIxodes (Pholeoixodes) hexagonus females was studied under controlled laboratory conditions of 22–23°C and 98% relative humidity. The feeding period of mated females was 6–15 days and 11–13 days for unmated females. The mean weight of the engorged mated females was 114.84±45.89 mg, whereas, that of the engorged unmated females was significantly lower (80.61±28.84 mg). During the initial slow feeding period, the weight of mated females increased 6.6 times. At the end of the blood feeding, they had increased their initial weight 35.5 times. Unmated females never entered the rapid engorgement phase and up to 12 days of feeding period their mean weight did not increase more than 9.2 times. The pre-oviposition periods of mated and unmated females were 6–15 days and 4–12 days, respectively. The mean of the egg production efficiency was 40.26±12.47% for mated females and 35.68±12.2% for unmated females. The mean of the mass conversion efficiency was 73.6±13.7% for mated females and 66.48 ±16.55% for unmated females. Sixty per cent of the eggs deposited by mated females hatched whereas only 1% of the eggs deposited by unmated females hatched. These results indicate thatI. hexagonus females possess some predisposition for parthenogenesis and only fertility and not fecundity depends on mating.