Edovum puttleri [Hym.: Eulophidae]: Biological activity and responses to normal and frozen eggs ofLeptinotarsa decemlineata [Col.: Chrysomelidae]

Biological control of eggplant pests in general, and (CPB)Leptinotarsa decemlineata (Say) in particular, is highly problematic.Edovum puttleri Grissell, an exotic egg parasitoid which has been found potentially effective, is being reared to this end. Frozen CPB eggs (?18°C) proved to be accepted and suitable for parasitization byE. puttleri. However, when given a choice between 20 frozen and 20 normal eggs every 2 days, the females exhibited a significant preference for the latter. Parasitization and host predation patterns related to female age are described by 2 opposing fourth-order polynomial functions. Parasitization increased up to day 10, followed by progressive decline. Average life span per female was 31.10±.58, with a recorded maximum of 56 days. High predatory behaviour of older females, which showed a decrease in parasitization, was observed in these experimental conditions.     

Dispersal and fighting in male pollinating fig wasps

For more than two decades, it has been the dogma that the males of pollinating fig wasps do not fight and that they only mate in their native fig. Their extreme degree of local mating leads to highly female biased sex ratios that should eliminate the benefits of fighting and dispersal by males. Furthermore, males sharing a fig are often brothers, and fighting may be barred by kin selection. Therefore, theory supported the presumed absence of fighting and dispersal in pollinating fig wasp males. However, we report here that in pollinating fig wasps, fighting between brothers evolved at least four and possibly six time, and dispersal by males at least twice. This finding supports the idea that competition between relatives can cancel the ameliorating effects of relatedness. The explanation to this evolutionary puzzle, as well as the consequences of male dispersal and fighting, opens the doors to exciting new research.     

A molecular understanding of complementary chromatic adaptation

Photosynthetic activity and the composition of the photosynthetic apparatus are strongly regulated by environmental conditions. Some visually dramatic changes in pigmentation of cyanobacterial cells that occur during changing nutrient and light conditions reflect marked alterations in components of the major light-harvesting complex in these organisms, the phycobilisome. As noted well over 100 years ago, the pigment composition of some cyanobacteria is very sensitive to ambient wavelengths of light; this sensitivity reflects molecular changes in polypeptide constituents of the phycobilisome. The levels of different pigmented polypeptides or phycobiliproteins that become associated with the phycobilisome are adjusted to optimize absorption of excitation energy present in the environment. This process, called complementary chromatic adaptation, is controlled by a bilin-binding photoreceptor related to phytochrome of vascular plants; however, many other regulatory elements also play a role in chromatic adaptation. My perspectives and biases on the history and significance of this process are presented in this essay. This revised version was published online in August 2006 with corrections to the Cover Date.     

46,XY女性性反转患者SRY基因的两个新突变类型

Y染色体上的性别决定区域——SRY基因作为睾丸决定因子,可以调控男性性别发育过程。SRY基因是一种转录因子,属于带有高迁移率族蛋白家族,该家族成员包含能与DNA结合的HMG盒基序。已知SRY基因的缺失和点突变是造成XY女性性反转的病因之一。通过筛查10位中国46,XY女性性反转病人SRY基因的开放阅读框区域,探寻新的突变类型。用标准方法从外周血中抽提gDNA,通过聚合酶链式反应扩增SRY基因中部的609bp的DNA片段。扩增后的PCR片段被克隆到pUCm-T载体中,在ABI377-3自动测序仪上完成测序。运用限制性内切酶酶切分析的方法验证DNA测序的结果。结果表明,在两个患者的SRY基因中分别发现了新的核苷酸点突变,并都导致氨基酸替代。一个突变发生在SRY基因的5’端HMG盒外的核苷酸第113位腺嘌呤(A)被鸟嘌呤(G)取代,并导致谷氨酸被甘氨酸替换;另一个突变是第387位核苷酸发生T被A替换,该突变引起第129位的酪氨酸变成终止密码,她父亲的SRY序列被证明是正常的野生型。通过查询文献和人类基因突变数据库(HGMD),这两个突变都是以前未见报道过的新型SRY基因突变,并使因核苷酸替换引起SRY基因突变总数增加到45。     

Unsuccessful induction of low-zone tolerance to bovine serum albumin injected into the subarachnoid space

Introduction of T-dependent antigens into the subarachnoid space (isas) resulted in higher systemic antibody responses in mice than injections into the peritoneal cavity (ip) or other sites commonly used for immunization. Antibody production in isas immunized mice was not increased by treatment with cyclophosphamide (Cy) at doses known to abolish T-suppressor-cell activity, but such treatment increased antibody production in ip immunized mice toward the higher level which was observed in the isas immunized animals. Suppressor cell-dependent low zone tolerance (LZT) to TNP-BSA could not be induced by isas injections of deaggregated BSA (d-BSA). Conversely, mice which were unresponsive to ip injected d-BSA showed consistent systemic antibody responses when the antigen was injected isas. These observations indicate that immune responses initiated within the CNS are associated with relatively ineffective induction of systemic suppressor cell activity.     

Utilisation de lois de la mécanique pour l'Estimationde la vitesse de locomotion des Vertébrés tétrapodes du passé

Two computation methods are explained; theirobject is the estimation of the velocity of animals which are known by their footprints, and in the case of the first method, by their skeletons as well.The first method is based on the compound pendulum theory, because during the slow walking gait, the motion of the leg is similar to the oscillation of a pendulum, for the computation of the velocity (v), are considered: moment of inertia (I), radius of gyration (P) and period (T), time in seconds to cover one stride (E) in the case the maximum angle of divarication (δ) of the leg with the vertical is ≤20°. A comparison with the formula of Alexander (1976) is discussed.The second method concerns saltator animals. It is based on the fondamental laws of dynamics. With the length of the jump (E) it is possible to estimate the velocity of the trackmaker (v) and the height of the jump (K). For the vertebrates the angle of the trajectory with the horizontal plan (α) is between 20 and 45°. Thus, the result of this method is an interval of estimation in which the velocity is included.These methods do not give precise results. But these approximations supply valid informations on the velocity of extinct or living animals and can lead to the estimation of their maximum speed if the parameters E, T, vary. The problem of the errors is also discussed. It is shown that the errors in estimating the parameters have a no significant influence on the results.     

Identification of rat brain polysomes synthesizing the brain specific enolase (14.3.2 protein), S100 protein and alpha and beta tubulin subunits

Polysomes prepared from frozen rat brain powder were fractionated by centrifugation in a sucrose gradient. Individual fractions were used to program a reticulocyte lysate in a run-off reaction. The products of cell-free synthesis were assayed for the brain-specific enolase (14.3.2 protein) and S100 protein by immunoprecipitation with specific antisera and for tubulin by two-dimensional electrophoresis in polyacrylamide slab gels. The relative synthesis of these proteins by unfractionated free brain polysomes were 0.1 per cent, 0.05 per cent and 0.7 per cent respectively. After centrifugation in a sucrose gradient polysomes synthesizing S100 protein were separated from those synthesizing the other two markers. There was a threefold enrichment in the specific messenger RNA activity for each of the three proteins studied in their respective peak fractions of polysomes.     

Blocking VLDL secretion causes hepatic steatosis but does not affect peripheral lipid stores or insulin sensitivity in mice

The liver secretes triglyceride-rich VLDLs, and the triglycerides in these particles are taken up by peripheral tissues, mainly heart, skeletal muscle, and adipose tissue. Blocking hepatic VLDL secretion interferes with the delivery of liver-derived triglycerides to peripheral tissues and results in an accumulation of triglycerides in the liver. However, it is unclear how interfering with hepatic triglyceride secretion affects adiposity, muscle triglyceride stores, and insulin sensitivity. To explore these issues, we examined mice that cannot secrete VLDL [due to the absence of microsomal triglyceride transfer protein (Mttp) in the liver]. These mice exhibit markedly reduced levels of apolipoprotein B-100 in the plasma, along with reduced levels of triglycerides in the plasma. Despite the low plasma triglyceride levels, triglyceride levels in skeletal muscle were unaffected. Adiposity and adipose tissue triglyceride synthesis rates were also normal, and body weight curves were unaffected. Even though the blockade of VLDL secretion caused hepatic steatosis accompanied by increased ceramides and diacylglycerols in the liver, the mice exhibited normal glucose tolerance and were sensitive to insulin at the whole-body level, as judged by hyperinsulinemic euglycemic clamp studies. Normal hepatic glucose production and insulin signaling were also maintained in the fatty liver induced by Mttp deletion. Thus, blocking VLDL secretion causes hepatic steatosis without insulin resistance, and there is little effect on muscle triglyceride stores or adiposity.