Mitosis in the haemocytes of Sarcophaga ruficornis (Diptera)

Among the haemocytes of Sarcophaga ruficornis, only the prohaemocytes divide. Injection of phytohaemagglutinin-P induces 100% prohaemocytes to undergo mitosis but does not induce mitosis in other cells. Mitotic stages other than the prophase are apparently very short lived.     

Sex attractant inhibitors of the codling mothLaspeyresia pomonella L.

Zusammenfassung Die Anlockung von Männchen des Apfelwicklers (Laspeyresia pomonella L.) mittrans-8,trans-10-Dodecadien-1-ol (Codlemone) oder mit lebenden Weibchen wird durch verschiedene Analoge des Sexuallockstoffs gehemmt. Starke Inhibitorwirkung zeigtecis-8-Dodecenylacetat. Der graue Knospenwickler,Hedya nubiferana Haw., der ebenfalls durch Codlemone angelockt wird, reagiert spezifisch auf weitere Inhibitoren.     

采用BDMA从硫酸溶液中液–液萃取分离磷

This study addresses the liquid-liquid extraction behavior of phosphorus from a sulfuric acid solution using benzyl dimethyl amine (BDMA) in kerosene. The extraction equilibria investigated with varied BDMA concentrations could reveal the formation of3[BDMA]·[H3PO4]complex in the organic phase. The thermodynamic properties determined at various temperatures indicated that the pro-cess was exothermic with a calculated enthalpy (△H(〇)) of ?24.0 kJ·mol?1. The organic-to-aqueous phase (O/A) volume ratio was varied to elu-cidate the quantitative extraction of phosphorus. The McCabe-Thiele diagram plotted for the extraction isotherm was validated for the require-ment of three counter-current stages in the extraction at an O/A volume ratio of 2.0/3.5. The back-extraction of phosphorus from the loaded or-ganic phase was quantitatively achieved by contacting 4.0 mol·L?1 H2SO4 solution in three stages of counter-current contact at an O/A volume ratio of 3/2. This study can be applied to remove phosphorus from the sulfuric acid leach solutions of monazite processing, and many other solutions.     

Effects of biodiversity on the functioning of trophic groups and ecosystems

Over the past decade, accelerating rates of species extinction have prompted an increasing number of studies to reduce species diversity experimentally and examine how this alters the efficiency by which communities capture resources and convert those into biomass. So far, the generality of patterns and processes observed in individual studies have been the subjects of considerable debate. Here we present a formal meta-analysis of studies that have experimentally manipulated species diversity to examine how it affects the functioning of numerous trophic groups in multiple types of ecosystem. We show that the average effect of decreasing species richness is to decrease the abundance or biomass of the focal trophic group, leading to less complete depletion of resources used by that group. At the same time, analyses reveal that the standing stock of, and resource depletion by, the most species-rich polyculture tends to be no different from that of the single most productive species used in an experiment. Of the known mechanisms that might explain these trends, results are most consistent with what is called the 'sampling effect', which occurs when diverse communities are more likely to contain and become dominated by the most productive species. Whether this mechanism is widespread in natural communities is currently controversial. Patterns we report are remarkably consistent for four different trophic groups (producers, herbivores, detritivores and predators) and two major ecosystem types (aquatic and terrestrial). Collectively, our analyses suggest that the average species loss does indeed affect the functioning of a wide variety of organisms and ecosystems, but the magnitude of these effects is ultimately determined by the identity of species that are going extinct.     

Germ-line transmission of a mutated p53 gene in a cancer-prone family with Li-Fraumeni syndrome

Tumour suppressor genes, whose usual function seems to be controlling normal cell proliferation, have been implicated in many inherited and sporadic forms of malignancies Much evidence supports the concept of tumour formation by loss-of-function mutations in suppressor genes, as predicted by the two-hit model of Knudson and DeMars. The suppressor gene, p53, is affected in such a manner by numerous mutations, which occur in a variety of human tumours. These mutations usually represent the loss of one allele and the substitution of a single base in the other. We have now analysed the p53 gene in a family affected by Li-Fraumeni syndrome, a rare autosomal dominant syndrome characterized by the occurrence of diverse mesenchymal and epithelial neoplasms at multiple sites. In some instances the neoplasms seem to be related to exposure to carcinogens, including ionizing radiation. The Li-Fraumeni family that we studied had noncancerous skin fibroblasts (NSF) with an unusual radiation-resistant phenotype. DNA derived from the NSF cells of four family members, spanning two generations, had the same point mutation in codon 245 (GGC----GAC) of the p53 gene. This mutation leads to substitution of aspartic acid for glycine in one of the regions identified as a frequent target of point mutations in p53. The NSF cell lines with the mutation also retained the normal p53 allele. This inherited p53 mutation may predispose the members of this family to increased susceptibility to cancer.