Egg protein insolubility inLymantria dispar versus other forest Lepidoptera

Summary A standard buffer (5 mM phosphate at pH 7) which is used to extract protein from insect eggs provided complete protein solubility for eggs from three of four tree-feeding lepidopteran species: obliquebanded leaf roller (Choristoneura rosaceana), forest tent caterpillar (Malacosoma disstria), and the eastern tent caterpillar (Malacosoma americanum). Under the same extraction protocol, egg proteins from the gypsy moth (Lymantria dispar), remained nearly insoluble. An array of methods typically used to solubilize insect egg proteins were tried and all but the most denaturing (2% SDS) were ineffective. Extraction buffers with typically high pH values were then evaluated. The results indicated that 1) solubility of gypsy moth egg proteins was pH dependent, and full solubility of most egg proteins required the extraction buffer to have a pH of 12 or more prior to the addition of eggs. We also determined that 2) the gypsy moth egg has a buffering capacity which must be surpassed for complete protein extraction, 3) low salt/high pH buffers gave slightly higher total protein values than did high salt/high pH buffers, 4) parental nutritional history (host species utilized) and egg developmental state (pre-embryonatedvs postembryonated/pre-hatch) were unrelated to the requirements for complete egg protein solubilization, and 5) the presence of soluble phenolics, compounds that have the potential to bind to protein and cause insolubility, was confirmed for the gypsy moth egg with 2-D paper chromatography and several other tests. Based on these results, we present a hypothesis about the cause of egg protein insolubility in the gypsy moth.     

The effect of 4-Nonylphenol on the pigmentation of<Emphasis Type="Italic">Ocimum basilicum</Emphasis> (Basil)

BACKGROUND, AIM AND SCOPE: Tests during the last few years have confirmed that 4-nonylphenol (4-NP) can have oestrogen-like effects (xeno-hormone) on animal organisms. The objective was to firstly evaluate the ecotoxicological effects of 4-NP on plants such as hydrocultures. To clarify how this substance interferes with the photosynthetic system of plants, various tests were carried out using the basil plant (Ocimum basilicum). METHODS: The effect of the pollutant 4-NP on the pigment content in the leaves of the basil plant was analysed with the use of High-Performance-Liquid-Chromatography (HPLC). RESULTS AND DISCUSSION: A general assessment of the HPLC data revealed that plants that came in contact with the 4-nonylphenol showed a change in pigmentation. More chlorophyll a and b was produced, although at the same time a higher production of degradation products and by-products of the chlorophylls was observed. These occurrences can therefore be seen as an impairment of the photosynthetic process. The contaminated plants produced less xanthophylls than the non-contaminated ones, though these differences were statistically not significant. CONCLUSION AND PERSPECTIVE: The variations on the pigment content in the leaves of the basil plant can be interpreted as a consequence of the 4-NP application. It was, however, not investigated whether the plants absorbed the pollutants directly. The effect could have been caused by adsorption of the oily substance to the roots, and this could have led to a hindrance of the uptake of nutrients and possibly water. In order to clarify this further, biochemical experiments are being conducted.     

Biodegradation of thermally synthesized polyaspartate

Polyaspartate synthesized using thermal methods (thermal polyaspartate; TPA) has been shown to have dispersant and crystallization inhibition activities. These activities suggest that the polymer may be used in water treatment and paper processing and as a detergent and paint additive. The commercial potential for TPA is enhanced by the fact that it may be synthesized on a large scale. Therefore, a study of the biodegradation of the polymer was undertaken. TPA was produced by hydrolysis of a polysuccinimide synthesized by dry thermal polymerization of aspartic acid. The resulting polymer was a poly(,-dl-aspartate) having a 70% structure and containing a racemic mixture of aspartic acid. TPA was incubated with both dilute effluent and activated sludge from a wastewater treatment plant. Low-biomass effluent experiments showed changes in molecular size of TPA concomitant with oxygen demand induced by the polymer, suggesting susceptibility of TPA to at least partial biodegradation. Low-biomass sludge experiments (SCAS, modified Sturm) yielded approximately 70% mineralization of 20 mg L^–1 TPA by 28 days, suggesting that a significant portion of the polymer was labile. High-biomass sludge experiments using¹⁴C-TPA at 1 mg L^–1 revealed approximately 30% mineralization and 95% total removal of TPA carbon from solution in 23 days, with most of the mineralization and removal taking place in less than 5 days. Additional short-term studies using a variety of particulate substrates, including activated sludge, confirmed that TPA is subject to removal from solution by adsorption. From these studies with labeled TPA, it was concluded that TPA is subject to rapid removal and at least partial degradation in a wastewaster treatment plant. Using gel and thin-layer chromatography, it was determined that at least part of the unmineralized residue from the high biomass assays was polyaspartate. It is speculated that the unusual structure of TPA compared to natural proteins may limit the rate of proteolysis of the polymer and thus its overall degradation rate.     

Thermal regime database of Ignalina Nuclear Power Plant cooler--Lake Drŭksiai

The hydrothermal regime of the Lake Druksiai has changedwhen it became a cooler for the Ignalina NPP. For 18 years, 1981–1998, the hydrologists from Lithuanian Energy Institute have been investigating thermal state of the lake. The water temperature data owned by the laboratory is unique as it has been collected sequentially during 18 yr under wide range of different weather and INPP capacity conditions. Gathered information consists of lake surface temperature, related meteorological data and INPP operating capacity data. This information enables not only to state that the relationship between hydrological and meteorological/INPP capacity data exists(that is already known) but also to analyze its character. The aim of this study was to build computer database for data analysis and management as well as to create digital maps for further modelling and forecasting. ArcView software package wasused for data set management and visualization.     

The leachate composition of an old waste dump connected to groundwater: Influence of the reclamation works

This study has been carried out in an uncontrolled dump in the suburbs of Buenos Aires, Argentina. This dump still contains solid wastes of different types in direct contact with the human consumption aquifer. After 18 years of overturning the dump was closed in 1992, and the reclamation works started.Three leachate samplings were carried out in three different zones of the dump, selected according to the topography, the age of residues and the degree of water contact. These samplings were done before the reclamation works, at the end, and four months after they were finished. Several chemical parameters, including heavy metals in solid and dissolved fractions, were analyzed.Multivariate analysis (PCA) was performed to help to understand the effects of the labors on leachate composition. The works could be responsible for a temporal increase of dissolved heavy metals and several chemical variables in the leachate. At the sites of the dump where the modifications were carried out, the levels of some elements analyzed recovered their former values a few months after the reclamations works. At the farthest site, the impact and recovery effects of the works on leachate composition, were delayed.     

高职院校产学研结合模式及其发展对策

本文提出怎样理解产学研相结合的问题,并从产学研不同层面进行分析,提出以市场为目标、以制度为保证实现产学研有效结合的思路。