Host specificity of the cassava green mite pathogen Neozygites floridana

Tests were conducted on the hostspecificity of a Brazilian isolate of thefungus Neozygites floridana, a potentialbiological control agent for the cassava greenmite, Mononychellus tanajoa, in Africa.Five insect and two mite species, mostly fromthe cassava agroecosystem, were evaluated forsusceptibility to N. floridana, namelyEuseius concordis, E. citrifolius, Phenacoccus herreni, Stethorus sp., Aleurothrixus aepim, Apoanagyrusdiversicornis, and Bombyx mori.Individuals of each species were exposed tocapilliconidia (the infective stage of thefungus). None of the tested individuals wasfound with hyphal bodies (the vegetative stageof the fungus), whereas 73 to 94% of thecassava green mites in the controls becameinfected. Non-germinated capilliconidia were,however, found attached to several individualsin most species. N. floridana appears tobe safe for exportation. Further evaluation ofits performance against M. tanajoa inAfrica is therefore desirable.     

Codon usage patterns among genes for lepidopteran hemolymph proteins

Patterns in codon usage were examined for the coding regions of the 23 known lepidopteran hemolymph proteins. Coding triplets are GC rich at the third position and a significant linear relationship between GC content of silent and nonsilent (replacement) sites was demonstrated. Intron GC content was significantly lower than in coding regions and no relationship between intron GC content and the same at silent and nonsilent sites was found. Though hemolymph proteins are all produced by the same tissue—fat body—significantly less bias was observed when all moth sequences were pooled than when sequences of the two major species were analyzed separately, as predicted by the genome hypothesis. In cases where no statistically significant bias was observed, polar or acidic basic amino acids were almost exclusively involved. Calculation of codon adaptation indices (CAI) was of limited value in quantifying the degree of codon bias and probably reflects the complexity of multicellular-organism life cycles and the changing patterns of gene expression over different developmental stages. Correspondence to: D.R. Frohlich     

Glutamine synthetase activity during embryonic and larval development of the silkworm Bombyx mori L. and role of a JH analogue

Abstract. Silkworm eggs of diapause nature were chilled or treated with hydrochloric acid. Glutamine synthetase activity in such treated eggs was present soon after the treatment, whereas in non-diapause eggs it was not detectable until 24 h after the start of development. During larval life, the glutamine synthetase was found to be absent in midgut tissue. Topical application of a JH analogue resulted in extened larval duration and it reduced glutamine synthetase activity initially, but in the latter part of development the activity was higher.     

The evolutionary dynamics of batesian and muellerian mimicry: similarities and differences

ABSTRACT. 1. The continuous spectrum of palatability can be divided without difficulty into two halves: the distasteful forms in one half tend to become models and muellerian mimics, the palatable forms in the other half to become batesian mimics.
2. Most of the traditionally recognized differences between batesian and muellerian mimicry are valid and useful: negative versus positive frequency-dependence, detriment versus benefit to the model, convergent evolution versus advergent evolution. None the less in both kinds, mimicry usually evolves by means of a major mutation whose effects are later modified. 'Supergenes' tend to be discovered more in batesian mimics than in muellerian mimics. This results from a complex interaction between natural selection on the one hand, and the origin of clusters of genes of related function through tandem duplication on the other.
3. Adaptation is not simply the creation of the best of all possible worlds: what natural selection can do is limited by what is possible for the gene.     

僵蚕药材酸溶性蛋白质的分离提取及鉴定

以Box-Behnken组合设计进行僵蚕药材酸法提取工艺的响应面优化,并对提取物中蛋白质进行定性定量分析。结果表明:酸法工艺获取僵蚕蛋白质的最佳条件为提取温度31. 8℃、提取时间3. 0 h、液料比49. 6∶1(V∶m)、醋酸钠缓冲液浓度0. 12 mol/L,此时蛋白质提取率为5. 34%。十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)指纹图谱结果表明,僵蚕酸溶性蛋白质主要分布于26 390～31 570和59 130～81 790区间,其中31 570与27 870蛋白约占总蛋白的59. 9%,71 700与81 790蛋白约占总蛋白的24. 3%。傅里叶变换红外吸收光谱(FTIR)结果表明,僵蚕酸溶性蛋白质具有特征性指纹图谱。上述结果有望用做僵蚕药材分子鉴定的依据,有助于僵蚕资源的开发利用。     

Reciprocal transplantation of wing discs between a wing deficient mutant (fl) and wild type of the silkworm, Bombyx mori

The wingless mutant flügellos ( fl ) of the silkworm lacks all four wings. Although wing discs of the fl seem to develop normally until the fourth larval instar, wing morphogenesis stops after the fourth larval ecdysis, probably caused by aberrant expression of an unidentified factor, referred to as fl . To characterize factor fl , the wing discs dissected from the wild-type (WT) and fl larvae were transplanted into other larvae and developmental changes of the discs were examined. When the wing disc from a WT larva was transplanted into another WT larva and allowed to grow until emergence, a small wing appeared that was covered with scales. Thus, the transplanted wing discs can develop autonomously, form scales and evert from adult skin. The WT wing discs transplanted into the fl larvae also developed at a high rate. However, the fl wing discs transplanted into the WT larvae did not develop during the larval to pupal developmental stages. These data suggest that the fl gene product (factor fl) works in the wing disc cells during wing morphogenesis. Its function cannot be complemented by hemolymph in the WT larva. It is also implied that the level of humoral factors and hormones required for wing morphogenesis are normally maintained in the fl larva.     

New pathway of utilization of ammonia nitrogen for the synthesis of amino acids through NADH dependent transaminases in Bombyx mori L.

Abstract. NADH dependent transamination was recorded for the first time in silkworm Bombyx mori (L.) eggs and in larval tissues. L-Glutamine:2–oxoglutarate amino transferase (GOGAT) and L-asparagine:2–oxoglutarate amino transferase (AOGAT) were determined in embryonic and also in larval tissues of multi-and bivoltine races. The presence of these two enzymes coupled to glutamine synthetase indicated efficient utilization of metabolic ammonia hitherto unknown in higher organisms. It is proposed that these transfer enzymes help in building the free amino acid pool seen during the diapause and also in the fibroin synthesis in the last larval stadium.     

Water vapour uptake by diapausing eggs of a tropical walking stick

Abstract. This study is the first to demonstrate the capacity of an arthropod egg, that of a tropical walking stick Extatosoma tiaratum (Macleuy), to absorb water vapour from the air. This species diapauses both as an early embryo and then again as a pharate first instar larva, and both stages are capable of absorbing water vapour. Water vapour absorption occurs at lower humidities and at a lower rate for an egg in early embryonic diapause (c. a_v 0.30, 0.516 mg h^-1δ_v^-1) than in the diapausing pharate first instar (c. a_v 0.60, 0.725 mgh^-1δa_v^-1) at 25C. In addition to having the capacity to gain water at very low vapour activities, water is efficiently conserved as indicated by the low rate of water loss (0.015% h^-1 in the early embryo and 0.046% h^-1 in the pharate larva at 25C). Eggs that have been killed lose water when held at a hydrating vapour activity, thus implying that active uptake contributes to net absorption. Wax block experiments suggest that water is absorbed over the entire chorionic surface. Eggs of five other insect species that were examined [Lymantria dispar (L.), Bombyx mori (L.), Antheraea polyphemus (Cram.), Oncopeltus fasciatus (Dallas) and Diaferomera femorata (Say)] lacked the ability to absorb atmospheric water.