Flight enhances juvenile hormone inactivation inDanaus plexippus plexippus L. (Lepidoptera: Danaidae)

Summary Adult Monarch butterflies injected with³H-juvenile hormone (JH) showed a significant increase in haemolymph JH metabolites after a 40 min flight compared to unflown controls. In addition, haemolymph enzymatic JH metabolism was shown to increase with thoracic temperature increases previously shown to be associated with flight.We thank Paul Cherubini for supplying California Monarchs, Dr L.I. Gilbert for his helpful suggestions, Jeanne Whitaker for secretarial assistance, and Henry Lessman for aid in insect culture.     

双取代簇阴离子RuCo3(CO)10(PPh3)2-与(PPh3Au)+的反应研究

双取代簇合物NEt4RuCo3(CO)10(PPh3)2与固体(PPh3Ay)Cl和TlPF6反应,生成了双取代簇合物AuPPh3RuCo3(CO)10(PPh3)2·CH2Cl2 Ⅰ后,双取代簇合物Ⅰ又逐渐转变为单取代簇合物AuPPh3RuCo3(CO)11(PPh3)Ⅱ.它们的组成和结构已通过元素分析、IR、31PNMR、59 Co NMR及有关反应验证.双取代簇合物Ⅰ中的两个取代基位置与反应物NEt4RuCo3(CO)10(PPh3)2中两个取代基的位置相同,即两个取代基中,一个占据与钴结合的位置(Co-P),而另一个占据与钌结合的位置(Ru-P).单取代簇合物Ⅱ中的一个取代基占据与钌结合的位置(Ru-P).     

爆炸产物JCZ状态方程的单组分当量值的确定方法

本文提出了一种确定Jacob?—Cowperthwaite—Zwisler状态方程单组分当量分子阱深?和σ的改进方法。此法用调整爆炸产物比热比的方法代替降低化学能方法,从而使确定单组分当量值的方法得到了显著改进。奥克托金炸药爆炸产物的单组分当量值已被精确地求得,并与TIGER编码的结果取得一致。这种单组分当量JCZ方程首先被用于燃烧转爆轰模型研究。它对奥克托金炸药的C—J特性给出了足够精确的预测。     

Effect of age,ambient temperature,and exposure to hormone on the posteclosion diuretic response of the monarch butterfly

Summary The monarch butterfly loses sensitivity to the posteclosion diuretic hormone of this species within 12 h of eclosion. This de-sensitization can be accelerated by exposure to the diuretic hormone, and decelerated by both hormone deficiency and reduced temperature.     

A re-examination of proximodistal patterning during vertebrate limb development

The 'progress zone' model provides a framework for understanding progressive development of the vertebrate limb. This model holds that undifferentiated cells in a zone of fixed size at the distal tip of the limb bud (the progress zone) undergo a progressive change in positional information such that their specification is altered from more proximal to more distal fates. This positional change is thought to be driven by an internal clock that is kept active as long as the cells remain in the progress zone. However, owing to cell division, the most proximal of these cells are continually pushed outside the confines of the zone. As they exit, clock function ceases and cells become fixed with the positional value last attained while within the zone. In contrast to this model, our data suggest that the various limb segments are 'specified' early in limb development as distinct domains, with subsequent development involving expansion of these progenitor populations before differentiation. We also find, however, that the distal limb mesenchyme becomes progressively 'determined', that is, irreversibly fixed, to a progressively limited range of potential proximodistal fates.     

Plant degradation: a nematode expansin acting on plants

Expansin proteins, which have so far been identified only in plants, rapidly induce extension of plant cell walls by weakening the non-covalent interactions that help to maintain their integrity. Here we show that an animal, the plant-parasitic roundworm Globodera rostochiensis, can also produce a functional expansin, which it uses to loosen cell walls when invading its host plant. As this nematode is known to be able to disrupt covalent bonds in plant cell walls, its accompanying ability to loosen non-covalent bonds challenges the prevailing view that animals are genetically poorly equipped to degrade plant cell walls.     

The gene mutated in bare patches and striated mice encodes a novel 3beta-hydroxysteroid dehydrogenase.

X-linked dominant disorders that are exclusively lethal prenatally in hemizygous males have been described in human and mouse. None of the genes responsible has been isolated in either species. The bare patches (Bpa) and striated (Str) mouse mutations were originally identified in female offspring of X-irradiated males. Subsequently, additional independent alleles were described. We have previously mapped these X-linked dominant, male-lethal mutations to an overlapping region of 600 kb that is homologous to human Xq28 (ref. 4) and identified several candidate genes in this interval. Here we report mutations in one of these genes, Nsdhl, encoding an NAD(P)H steroid dehydrogenase-like protein, in two independent Bpa and three independent Str alleles. Quantitative analysis of sterols from tissues of affected Bpa mice support a role for Nsdhl in cholesterol biosynthesis. Our results demonstrate that Bpa and Str are allelic mutations and identify the first mammalian locus associated with an X-linked dominant, male-lethal phenotype. They also expand the spectrum of phenotypes associated with abnormalities of cholesterol metabolism.