Oviposition of the Colorado potato beetle (Leptinotarsa decemlineata) and natural predation on its egg masses in Bt-expressing fields

Generalist predators are relevant natural enemies of the Colorado potato beetle (CPB) in Europe. In fields of insect resistant genetically modified plants (GMPs), predators could be exposed to toxins either directly (e.g., via pollen), or indirectly through feeding on herbivorous prey. Hence, they represent an important functional group to consider when studying environmental impacts of GMPs. CPB females show a ‘bet-hedging’ strategy in spatial and temporal distribution of eggs, through which the species tries to minimize the risks of progeny loss due to adverse conditions. Experimental fields of GM eggplants expressing Cry3Bb toxin and potatoes expressing Cry1Ab toxin were set up. CPB egg masses were counted on naturally infested plants at four time points during the field season of each crop. To assess predation, newly deposited egg masses were marked at the same dates. Daily visual observations were conducted recording the numbers of intact or preyed eggs and neonate larvae. In both cases, oviposition was similar between GM and control plots, as the number of egg masses per plant and the number of eggs per mass did not differ significantly between treatments. A statistical analysis of the spatial distribution of egg masses revealed a similar aggregation in the potato field, whereas in the eggplant field, the variance of the number of egg masses per plant was smaller than expected in GMP plots. The predation rate was similar between treatments. These results suggest that the ecological function of natural predation on CPB eggs in GM plots was not impaired.     

Drin pesticides removal from aqueous solutions using acid-treated date stones

This work describes the potential applicability of chemically and thermally treated date stones for removing drin pesticides (aldrin, dieldrin and endrin) from aqueous solutions. The effect of several parameters, such as sorbent particle size, adsorbent dose, shaking speed, shaking time, concentration of pesticide solution and temperature, was evaluated by batch experiments. Pesticide determination was carried out using stir bar sorptive extraction and gas chromatography coupled with mass spectroscopy. Maximum removal efficiency (93%) was reached using 0.1 g of acid-treated date stones (ATDS) (63–100 μm) and 100 mL of aldrin (0.5 mg L⁻¹). The removal efficiency of drin pesticides decreased in the order of aldrin, dieldrin and endrin, and decreased as the temperature rose. Adsorption data were processed according to various kinetic models. Lagergren and Morris-Weber equations were applied to fit the kinetic results. The second order model was the most suitable on the whole, and intra-particle diffusion was found to be the rate-controlling the adsorption process. According to adsorption kinetic data, 3.5 h were considered as the equilibrium time for determining adsorption isotherms. Adsorption data were analyzed by the Langmuir, Freundlich and Dubinin–Radushkevich adsorption approaches. Experimental results showed that the Freundlich isotherm model best described the adsorption process. In addition, thermodynamic parameters such as ΔH, ΔS and ΔG were calculated. Negative values of ΔH and ΔG indicate the exothermic and spontaneous nature of pesticide adsorption on ATDS.     

DFT and MP2 studies on the C2C2α bond cleavage in thiamin catalysis

Thiamin diphosphate (ThDP), the biologically active derivative of vitamin B₁, is an important cofactor of several enzymes that catalyze the oxidative and non-oxidative conversion of α-keto acids. The final step of non-oxidative decarboxylation of pyruvate by pyruvate decarboxylase – the liberation of acetaldehyde – requires deprotonation of the α-hydroxyl group and cleavage of the C2–C2α bond of the transitory 2-(1-hydroxyethyl)-ThDP intermediate. It has been proposed that the cofactor 4′-amino/imino function is essentially involved in the deprotonation of the α-hydroxyl group. Proton transfer and C2–C2α cleavage may occur in a stepwise manner, or, alternatively in a concerted mechanism. Here, density functional theory (DFT) calculations as well as second order Møller–Plesset perturbation theory (MP2) studies were performed on a simple model for the enzyme using the program package Gaussian 03. Calculations favor a stepwise mechanism with initial formation of the C2α alkoxide, followed by C2–C2α bond cleavage.     

Frequent overexpression of CADM1/IGSF4 in lung adenocarcinoma

We reported comprehensive screening for antigens (Ags) overexpressed on various carcinomas via isolation of human monoclonal antibodies (mAbs) that may be therapeutic in a previous paper (Proc. Natl. Acad. Sci. USA 105, 7287-7292, 2008). Twenty-one distinct Ags highly expressed on several carcinomas were identified and 356 mAbs with unique sequences turned out to bind to one of the 21 Ags. Among them CADM1/IGSF4 which had been originally referred to as tumor suppressor lung cancer 1 (TSLC1) was included. Therefore we examined the expression of CADM1 in lung cancers in this study. Eight different anti CADM1 mAbs were used for immunohistochemical analysis of 29 fresh lung cancer specimens. Staining patterns were categorized to six groups based on the extent of positive staining and the localization of stained portions. While overexpression of CADM1 was observed on the cell surface of adenocarcinomas at a high frequency, around 60%, positive stainings were rarely observed on that of other lung carcinomas including squamous cell carcinomas. Moreover, some clones among the eight mAbs gave different staining patterns from those by the other clones against the same fresh specimen, suggesting presence of variant forms of CADM1 differentiated by mAbs.     

Bt maize fed-prey mediated effect on fitness and digestive physiology of the ground predator Poecilus cupreus L. (Coleoptera: Carabidae)

We investigated the effects of a Bt maize hybrid on fitness and digestive physiology of the ground-dwelling predator Poecilus cupreus L., as compared with the near-isogenic hybrid. A tritrophic assay revealed that there was a great decline in the detection of Cry1Ab toxin through the trophic chain, the concentration of the toxin being 945, 349 and 37 ng g⁻¹ of fresh weight in Bt maize leaves, Spodoptera littoralis (Boisduval) larvae and P. cupreus larvae, respectively. Moreover, the toxin was only detected in 8% of the P. cupreus adults collected from fields growing Bt maize. Developmental time of both larvae and pupae of P. cupreus was not adversely affected by the Cry1Ab toxin via fed-prey. To elucidate potential detrimental effects due to a reduction in the quality of the prey, we assessed the digestive proteolytic activities of P. cupreus adults from a laboratory culture and insects collected in commercial Bt and non-Bt maize fields. Field-collected P. cupreus adults had higher proteolytic activities than those reared in the laboratory, whereas no significant differences were found between P. cupreus adults reared on Bt and non-Bt maize fed-S. littoralis or between P. cupreus adults collected in commercial Bt and non-Bt maize fields.     

Structure and Energetics of Encapsidated DNA in Bacteriophage HK97 Studied by Scanning Calorimetry and Cryo-electron Microscopy

Encapsidation of duplex DNA by bacteriophages represents an extreme case of genome condensation, reaching near-crystalline concentrations of DNA. The HK97 system is well suited to study this phenomenon in view of the detailed knowledge of its capsid structure. To characterize the interactions involved, we combined calorimetry with cryo-electron microscopy and native gel electrophoresis. We found that, as in other phages, HK97 DNA is organized in coaxially wound nested shells. When DNA-filled capsids (heads) are scanned in buffer containing 1 mM Mg²⁺, DNA melting and capsid denaturation both contribute to the complex thermal profile between 82 °C and 96 °C. In other conditions (absence of Mg²⁺ and lower ionic strength), DNA melting shifts to lower temperatures and the two events are resolved. Heads release their DNA at temperatures well below the onset of DNA melting or capsid denaturation. We suggest that, on heating, the internal pressure increases, causing the DNA to exit—probably via the portal vertex-while the capsid, although largely intact, sustains local damage that leads to an earlier onset of thermal denaturation. Heads differ structurally from empty capsids in the curvature of their protein shell, a change attributable to outwards pressure exerted by the DNA. We propose that this transition is sensed by the portal that is embedded in the capsid wall, whereupon the structure of the portal and its interactions with terminase, the packaging enzyme, are altered, thus signaling that packaging is at or approaching completion.     

Ab initio protein modelling reveals novel human MIT domains

Database searches can fail to detect all truly homologous sequences, particularly when dealing with short, highly sequence diverse protein families. Here, using microtubule interacting and transport (MIT) domains as an example, we have applied an approach of profile-profile matching followed by ab initio structure modelling to the detection of true homologues in the borderline significant zone of database searches. Novel MIT domains were confidently identified in USP54, containing an apparently inactive ubiquitin carboxyl-terminal hydrolase domain, a katanin-like ATPase KATNAL1, and an uncharacterized protein containing a VPS9 domain. As a proof of principle, we have confirmed the novel MIT annotation for USP54 by in vitro profiling of binding to CHMP proteins.

Structured summary

USP8 binds:CHMPs 1A 1B 2A 2B 4CUSP54 binds:CHMPs 1B 2A 2B 4C 6     

Theoretical study of spin-spin coupling across the hydrogen (O-H⋯N) bond in adenosine derivatives

The study of spin-spin coupling constants across hydrogen bond provides useful information about configuration of complexes. The interesting case of such interactions was observed as a coupling across an intramolecular hydrogen bond in 8-bromo-2′,3′-O-isopropylideneadenosine between the -CH₂OH (at 5″ proton) group and the nitrogen atom of adenine. In this paper we report theoretical investigations on the ^4h J _NH coupling across the H″-C-O-H···N hydrogen bond in adenosine derivatives in various solvent models. Figure Coupling constants in 8-bromo-2′,3′-O-isopropylideneadenosine Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

转cry1Ab/vip3H+epsps基因粳稻对非靶标害虫稻叶蝉田间种群的影响

转基因作物可能带来的风险之一是对非靶标生物尤其是非靶标植食者产生潜在的影响。本研究采用吸虫器取样法, 通过在浙江长兴2地点3年的试验评价了新型抗虫/耐除草剂转cry1Ab/vip3H+epsps基因粳稻（G6H1）及其亲本对照（秀水110, XS110）对稻叶蝉田间种群动态的影响。结果表明： 叶蝉类主要有黑尾叶蝉Nephotettix cincticeps (Uhler)、 二点叶蝉Cicadula fascifrons (Stål)和电光叶蝉Deltocephalus dorsalis Motschulsky组成, 其中黑尾叶蝉是优势种。虽然3种叶蝉的种群密度随着地点和年份的不同有所不同, 但是转基因水稻对3种叶蝉种群密度的年度变化均没有显著性影响。少数年份, 黑尾叶蝉成虫、 若虫及其两者总密度的时间动态在转基因水稻和对照田之间存在差异, 大多数年份, 趋势一致且无显著差异 （P>0.05）。另外, 二点叶蝉和电光叶蝉种群的时间动态在转基因水稻和对照田之间也相似。综合评价认为, 本供试转基因水稻品系G6H1对稻田稻叶蝉种群无明显的负面影响。     

Immunoproteasome expression is induced in mesial temporal lobe epilepsy

Immunoproteasome has been associated to neurodegenerative and autoimmune diseases as a marker and regulator of inflammatory mechanisms. Its expression in the brain may occur upon neuroinflammation in different cell types and affect a variety of homeostatic and inflammatory pathways including the oxidized protein clearance and the self-antigen presentation. In the present study we investigated the immunoproteasome expression in hippocampi and cortex of patients affected by different histopathological forms of pharmaco-resistent mesial temporal lobe epilepsy. We identified a pathology-specific pattern of immunoproteasome expression, which could provide insight into the complex neuroinflammatory pathogenic components of this disease.