苏云金杆菌预处理小菜蛾对有机磷和氨基甲酸酯杀虫剂的增效作用

研究了小菜蛾Plutella xylostella幼虫经苏云金杆菌Bacillus thuringiensis预处理后,对有机磷和氨基甲酸酯杀虫剂敏感性的变化以及预处理对小菜蛾幼虫体内乙酰胆碱酯酶、羧酸酯酶、谷胱甘肽S-转移酶和谷胱甘肽的含量的影响。结果表明：苏云金杆菌预处理抗性小菜蛾幼虫后,其对甲胺磷、水胺硫磷和克百威的敏感性分别为未处理组的6.74、8.83和8.50倍;处理敏感小菜蛾幼虫后则分别为未处理组的2.96、1.69和3.88倍。苏云金杆菌预处理抗性小菜蛾,未处理组乙酰胆碱酯酶的K_m和V_max值分别为预处理组的1.86和1.56倍,所使用的6种杀虫剂对乙酰胆碱酯酶的K_I值,处理组为未处理组的1.80～2.66倍,苏云金杆菌预处理抗性小菜蛾对羧酸酯酶的K_m、K_I影响不大,但能显著地抑制羧酸酯酶和谷胱甘肽S-转移酶的活性并导致谷胱甘肽含量下降(对照分别为处理的2.02、1.76和1.66倍)。苏云金杆菌预处理敏感小菜蛾,对乙酰胆碱酯酶的K_m、V_max、K_I值和羧酸酯酶的K_m、K_I值以及谷胱甘肽含量影响不大,但能显著地抑制羧酸酯酶和谷胱甘肽S-转移酶的活性(对照分别为处理的1.54和1.64倍)。     

2,3,5-triphenyltetrazolium chloride as a viability assay for immobilized plant cells

Grape (V. vinifera L. cv Gamay Fréaux) cells were entrapped in calcium alginate beads. The effect of bead diameter and gel concentration on the viability of the cells was checked. The reduction of 2,3,5-triphenyltetrazolium chloride as well as O₂ consumption were used as viability test, and their results compared. The existence of diffusional limitations for O₂ introduces an unaccuracy as high as 25% for the O₂ consumption method. The reduction assay is more simple, precise and reliable.     

Effects of miaA on translation and growth rates

Summary We have measured the growth rates and elongation rates for different proteins in wild-type, miaA, rpsL, and miaA, rpsL double mutants of Escherichia coli in the presence as well as the absence of streptomycin. The data show that while miaA and rpsL mutants inhibit elongation rates to equivalent levels, miaA inhibits the growth rate twice as effectively as does rpsL. The double mutant is more effectively inhibited than either single mutant and Sm repairs in part the growth rate as well as protein elongation rates. The data suggest that the conditional streptomycin-dependent phenotype of the double mutant cannot be due simply to the depressed polypeptide elongation rates of the double mutant.     

Joyeuses Tropiques: Five Encounters with Alterities in Brazil

The paper describes the predicament of Brazilian anthropology through a personal experience of teaching and living in Brasilia. Just like Brasilia, Brazil is many ways considered as “a work in progress” – and Brazilian anthropology as a lively and thriving area, although frequently overlooked by non-Brazilian scholars. The situation in which Brazilian anthropologists find themselves is put in the context of their own history, as well as the particular social conditions of the country – with special reference to Brazil as invention, taking as an example celebration of “500 years of Brazil.”     

Chemical Composition and Content of Lipophilic Seed Extractives of Some Abies and Picea Species

The chemical content and composition of the lipophilic extracts from seeds of some fir species: Abies alba, A. cephalonica, A. concolor, and A. koreana, as well as of a few spruce species: Picea abies, P. orientalis, and P. pungens, were examined. The amount of lipophilic extractives is diverse among the tree species and it varies from 9.8% to 41% of seeds. The chemical characterization showed significant differences, not only in the content, but also in the composition of extractives. However, most of the identified compounds like resin alcohols, ‐aldehydes, and ‐acids, as well as fatty acids, were detected in the seed extracts of all the examined tree species. The dominating identified compound group was esterified fatty acids (2.5 – 55.4% w/w of dry extract), occurring mainly as tri‐ and diglycerides, as well as free acids. The main representatives of this group were linoleic and oleic acids. The resin acids, among which the main were abietic, neoabietic, dehydroabietic, and palustric acids, were also detected at high levels, from 1.8% to 16.9% of the dry seed extracts. Phytosterols, tocopherols, resin hydrocarbons, and resin esters, as well as fatty alcohols were also identified. The coniferous tree seeds, as a renewable natural material, could represent a prospective raw material for producing valuable chemicals.     

Discovery of novel and potent aryl diamines as leukotriene A4 hydrolase inhibitors

The synthesis and biological evaluation of a series of aryl diamines as inhibitors of LTA₄-h inhibitors are described. The optimization which led to the identification of the optimal para-substitution on the diphenyl ether moiety and diamine spacer is discussed. The resulting compounds such as 3l have excellent enzyme and cellular potency as well as desirable pharmacokinetic properties.     

Topological analysis of aromatic halogen/hydrogen bonds by electron charge density and electrostatic potentials

In this work, the intermolecular distribution of the electronic charge density in the aromatic hydrogen/halogen bonds is studied within the framework of the atoms in molecules (AIM) theory and the molecular electrostatic potentials (MEP) analysis. The study is carried out in nine complexes formed between benzene and simple lineal molecules, where hydrogen, fluorine and chlorine atoms act as bridge atoms. All the results are obtained at MP2 level theory using cc-pVTZ basis set. Attention is focused on topological features observed at the intermolecular region such as bond, ring and cage critical points of the electron density, as well as the bond path, the gradient of the density maps, molecular graphs and interatomic surfaces. The strength of the interaction increases in the following order: F⋅⋅⋅π < Cl⋅⋅⋅π < H⋅⋅⋅π. Our results show that the fluorine atom has the capability to interact with the π−cloud to form an aromatic halogen bond, as long as the donor group is highly electron withdrawing. The Laplacian topology allows us to state that the halogen atoms can act as nucleophiles as well as electrophiles, showing clearly their dual character.     

Distribution of Macrophage Centres in Bream (Abramis brama L.) Liver from the Oder River (Germany/Poland) within the Nature Reserve “Unteres Odertal” Near the Town of Schwedt

The livers of bream (Abramis brama) from the Oder River near the town of Schwedt (Germany), were investigated for their content of macrophage centres (MCs). The investigations were carried out for a period of 18 months. The mean MC-number was 20 ± 14 MCs per mm² in females and 13 ± 11 MCs per mm² in males. These values are regarded as normal for adult bream of the Oder River. The diameter of the MCs ranged between 8 and 160 μm for both sexes. The study showed positive correlations between the MC-response and water pH as well as water temperature. Different correlations existed between males and females and the water temperature. The use of histological analyses of liver MC-size and -number as a biomarker is discussed. Currently the MC-response is only regarded as an unspecific biomarker on environmental stress.     

Platelet and cardiovascular activity of the hydantoin BW245C, a potent prostaglandin analogue

The platelet anti-aggregating, cardiovascular and gastro-intestinal actions of a hydantoin prostaglandin analogue, BW245C have been compared with prostaglandin and PGD₂ several species. In human plasma , BW245C was 0.2 times as active as prostacyclin and 8 times as active as PGD₂ in inhibiting platelet aggregation. In rat and rabbit plasma, BW245C was only weakly active but was more potent in sheep and horse plasma. Since the acivity of PGD₂ varied in a parallel fashion, BW245C may interactive with PGD₂ binding sites on platelets. The potency of BW245C as a vasodepressor also varied between species, being 0.5, 0.1, 0.06 and < 0.02 times as active as prostacyclin in the aneasthetised dog, monkey, rat and rabbit respectively.The relative activity of BW245C as an inhibitor of platelet aggregation was more comparable, being 0.08, 0.04 and 0.05 times as active as prostacyclin following intravenous infusion in the rabbit dog and monkey respectively. In the rabbit, BW245C was a highly selective platelet inhibitor with minimal cardiovascular actions, whereas in the dog and monkey, BW245C lowered BP in anti-aggregating doses. The potent platlet anti-aggregating actions of BW245C following parenteral or oral administration makes this hydantoin a potentially-useful anti-thrombotic prostaglandin analogue.     

Thiol S-methyltransferase from rat liver.

The thiol S-methyltransferase from rat liver has been solubilized and prepared in homogeneous form. The enzyme exists in a monomer of M_r 28,000 although enzyme activity is highly unstable with a half-life of 4 days under the best conditions of storage. The reaction requires S-adenosylmethionine as methyl donor but, as is the case with many enzymes active in detoxification, a large variety of lipophilic compounds can serve as acceptors. Acceptor activity is limited to thiols. The naturally occurring hydrophilic thiols, glutathione and cysteine, act neither as substrates nor as inhibitors. The course of the reaction is biphasic with an initial rapid formation of product that is followed by a slower linear rate. The suggestion is offered that this behavior reflects the slow dissociation of an enzyme-product complex composed of enzyme and S-adenosyl-homocysteine.     

Synthesis and structure–activity relationships of 2-aryl-4-oxazolylmethoxy benzylglycines and 2-aryl-4-thiazolylmethoxy benzylglycines as novel,potent PPARα selective activators- PPARα and PPARγ selectivity modulation

The synthesis and follow-up SAR studies of our development candidate 1 by incorporating 2-aryl-4-oxazolylmethoxy and 2-aryl-4-thiazolylmethoxy moieties into the oxybenzylglycine framework of the PPARα/γ dual agonist muraglitazar is described. SAR studies indicate that different substituents on the aryloxazole/thiazole moieties as well as the choice of carbamate substituent on the glycine moiety can significantly modulate the selectivity of PPARα versus PPARγ. Potent, highly selective PPARα activators 2a and 2l, as well as PPARα activators with significant PPARγ activity, such as 2s, were identified. The in vivo pharmacology of these compounds in preclinical animal models as well as their ADME profiles are discussed.     

An Improved Computational Prediction Model for Lysine Succinylation Sites Mapping on Homo sapiens by Fusing Three Sequence Encoding Schemes with the Random Forest Classifier

Background Lysine succinylation is one of the reversible protein post-translational modifications (PTMs), which regulate the structure and function of proteins. It plays a significant role in various cellular physiologies including some diseases of human as well as many other organisms. The accurate identification of succinylation site is essential to understand the various biological functions and drug development.Methods In this study, we developed an improved method to predict lysine succinylation sites mapping on Homo sapiens by the fusion of three encoding schemes such as binary, the composition of k-spaced amino acid pairs (CKSAAP) and amino acid composition (AAC) with the random forest (RF) classifier. The prediction performance of the proposed random forest (RF) based on the fusion model in a comparison of other candidates was investigated by using 20-fold cross-validation (CV) and two independent test datasets were collected from two different sources.Results The CV results showed that the proposed predictor achieves the highest scores of sensitivity (SN) as 0.800, specificity (SP) as 0.902, accuracy (ACC) as 0.919, Mathew correlation coefficient (MCC) as 0.766 and partial AUC (pAUC) as 0.163 at a false-positive rate (FPR) = 0.10 and area under the ROC curve (AUC) as 0.958. It achieved the highest performance scores of SN as 0.811, SP as 0.902, ACC as 0.891, MCC as 0.629 and pAUC as 0.139 and AUC as 0.921 for the independent test protein set-1 and SN as 0.772, SP as 0.901, ACC as 0.836, MCC as 0.677 and pAUC as 0.141 at FPR = 0.10 and AUC as 0.923 for the independent test protein set-2. It also outperformed all the other existing prediction models.Conclusion The prediction performances as discussed in this article recommend that the proposed method might be a useful and encouraging computational resource for lysine succinylation site prediction in the case of human population.     

Synthesis of fluorinated C-mannopeptides as sialyl Lewisx mimics for E- and P-selectin inhibition

The synthesis of fluorinated C-mannopeptides and their evaluation as E- and P-selectin inhibitors is described. These molecules are difluorinated analogues of CH₂-glycopeptides already reported to act as sLe^x mimics. The α and β anomers of these CF₂-glycopeptides have been prepared, as well as their 1-hydroxy analogues which were present in solution as an equilibrium mixture of α- and β-pyranose and α- and β-furanose forms. These molecules showed inhibitory activities comparable to their CH₂ counterparts with a moderate influence of the pseudo-anomeric center configuration.     

A Further Numerical Taxonomic Study of the Rhodochrous Group

A computer taxonomy was carried out as an aid to clarify the relationships between the genera Mycobacterium, and Nocardia as well as the ‘Rhodochrous’ group. The last group contained slightly acid-fast organisms isolated from sputa and soil and also included strains received as “Mycobacterium rhodochrous.” The group had been proposed as the genus Gordona by the present author. The rhodochrous group formed a cluster at the 87% similarity level and was clearly separated from all strains of the genera Mycobacterium and Nocardia. The cluster of the rhodochrous group was divided into seven subclusters at the 90% similarity level, and six of the seven corresponded to six species of the genus Gordona: G. bronchialis; G. rubropertincta (synonym G. rubra); G. terrae; G. aurantiaca; G. rhodochroa; G. rosea. If one accepts the concept that a phenetically well-defined cluster is a species, each of the subclusters of the rhodochrous group should be regarded as a species and the entire group as a genus. Discrepancies between the results of numerical classification and the results of lipid analyses remain as a problem to be solved in the future.     

Production, Purification, and Characterization of Recombinant Human Hemoglobin Rainier Expressed inSaccharomyces cerevisiae

Hemoglobin Rainier is a naturally occurring hemoglobin variant in which the β145 tyrosine is substituted with cysteine. The α and β^Rainierglobin cDNAs were cloned in a high copy number vector and expressed inSaccharomyces cerevisiaeunder the control of galactose-regulated hybrid promoters. Using this system, we have expressed individual α and β^Rainierglobin chains. Coexpression of both α and β^RainiercDNAs resulted in the production of a functional hemoglobin molecule. Purification of the recombinant protein was accomplished by ion exchange chromatography. The N-termini of the α and β chains were correctly processed, and the molecular mass, as determined by mass spectrometry, indicated amino acid composition identical to that of natural hemoglobin Rainier. The chromatographic properties of the recombinant hemoglobin Rainier were similar to human-derived hemoglobin A₀. The purified recombinant hemoglobin molecule was shown to have an elevated oxygen affinity and a reduced cooperativity as previously reported for natural hemoglobin Rainier. Production of recombinant hemoglobin and especially hemoglobin variants like hemoglobin Rainier has the potential to facilitate use of hemoglobin as a blood substitute as well as in specific applications, such as for use as a therapeutic agent in the treatment of hypotension associated with septic shock.     

Role of morphological variables of the visitor butterfly species in relation to their foraging behaviour on Lantana camara: Implication for conservation

The study of foraging behaviour of butterflies has been an important focus among the lepidopterists for years. Although established as invasive weed plant, the role Lantana camara as an important host plant as well as a food plant for the butterfly species is now well-known. The present study aims to interpret the role of morphological variables of the visitor butterflies in relation to their foraging behaviour on Lantana camara. Butterflies with longer proboscis were more efficient in foraging on flowers of Lantana camara than the butterflies with shorter ones, when the species containing proboscis same as or longer than their body length were excluded. Longer relative proboscis length (RPL) have selective advantage for foraging over Lantana camara up to a certain point (RPL = 0.881) and after that larger relative proboscis length often obstructs foraging behaviour as the handling time increases and these butterflies face more resistance against incoming nectar than the others.The residuals (body weight-wing span) also act as important factor.The handling time of the butterflies on Lantana camara shows a negative relationship with the residuals. The findings suggests that in case of Lantana camara as a nectaring plant butterfly species with longer proboscis have selective advantage for exploitation of the resource than the species with shorter ones and plantation of Lantana camara may be useful for conserving the long tongued butterfly species.     

Novel pre-treatment processes to promote linen-containing fabrics properties

This study was undertaken to investigate the effect of plasma pre-treatment, followed by enzymatic treatment in the absence and presence of bleaching agent on the properties of linen and linen-containing fabrics. Different plasma gases (air, oxygen and nitrogen), enzymes (acid-cellulases, neutral-cellulase and alkaline-pectinase) as well as bleaching agents (peracetic acid and H₂O₂) were used. The changes in physico-mechanical properties, surface morphology and dyeing properties of the treated substrates have been investigated. The obtained results indicated that plasma pre-treatment followed by subsequent acid-cellulases/peracetic acid or alkaline-pectinase/H₂O₂ treatment result in: a dramatic improvement in hydrophilicity and wettability as well as in the degree of whiteness of the treated substrates, an improvement in reduction of surface roughness and extent of post-reactive dyeing, along with a weight loss and a drop in the tensile strength. The extent of surface modification as well as the changes in the above-mentioned properties are governed by the characteristics of the substrate, the plasma gas, the nature and dose of the used enzyme, as well as the type of bleaching agent and additive. The optimal treatment sequence for attaining better performance properties was O₂-plasma followed by alkaline-pectinase/H₂O₂ treatment in presence of PEG 400.     

Effect of CuSO4 and Cu(II)(Gly)2 on some indirect assays for superoxide dismutase activity

The effect of CuSO₄ and Cu(II)(Gly)₂ has been compared with that of superoxide dismutase on the ferricytochrome c reduction and on the nitroblue tetrazolium reduction by an enzymic or chemical flux of superoxide anion radicals as well as on o-dianisidine photooxidation. Both CuSO₄ and Cu(II)(Gly)₂ have been found to inhibit ferricytochrome c reduction as well as the aerobic and anaerobic nitroblue tetrazolium reduction with approximately equal efficiency. Unlike superoxide dismutase they proved capable of inhibiting o-dianisdine photooxidation. The effect of copper either as CuSO₄ or as Cu(II)(Cly)₂ has been established as being due to its interference with the indirect assays for superoxide dismutase activity used. The reasons for this interference have been examined and it is concluded that copper can react with a component of the indirect assay system and depending on the method used it either mimics SOD or acts contrary to the enzyme.     

Effect of N-Linked Glycosylation on Secretion, Activity, and Stability of α-Amylase from Aspergillus oryzae

The effect of N-linked glycosylation on secretion, activity, and stability of α-amylase from Aspergillus oryzae grown as dispersed filaments was studied. In the presence of tunicamycin the fungus grew either as dispersed filaments or as one large pellet, whereas growth was as dispersed filaments in all control cultures. The presence of tunicamycin affected neither biomass, level of secreted α-amylase, nor total amount of secreted protein in cultures growing as dispersed filaments. In these cultures both glycosylated and nonglycosylated α-amylase appeared in the culture medium as well as in the cells, whereas in control cultures only the glycosylated form of α-amylase was found in the medium and in the cells. The presence of nonglycosylated α-amylase in the medium seemed to result from active secretion rather than from autolysis of the mycelium or extracellular deglycosylation. Deglycosylation with Endo H of crude α-amylase in culture filtrate did not affect its stability towards heat, acid pH, or proteolytic degradation. Received: 22 December 1997 / Accepted: 24 February 1998     

Thermodynamic study of β-galactosidase for high pressure separation processes

Summary The reaction of β-galactosidase with o-nitrophenyl-\-D-galactopyranoside was studied as a function of pressure and temperature. The observed activation volume was strongly dependent on the temperature. The calculation of the Maxwell relationships as well as the extrapolation of the pressure dependence f the In V_o versus pressure curves show that the system is thermodynamically consistent.