Influence of Atlantic Rain Forest remnants on the biological control of Euselasia apisaon (Dahman) (Lepidoptera: Riodinidae) by Trichogramma maxacalii (Voegelé e Pointel) (Hymenoptera: Trichogrammatidae)

This study evaluated the effects of Atlantic Rain Forest remnants on the natural biological control of Euselasia apisaon (Dahman) by the parasitoid Trichogramma maxacalii (Voegelé e Pointel) in Eucalyptus plantations. The number of E. apisaon eggs/leaf was higher in the center than in the edge of the plantations (23.5 +/- 7.61 vs. 14.8 +/- 3.14), but parasitism showed the reversed pattern (72.4% in the center and 80.5% in the edge). The results indicated that natural regulation exerted by T. maxacalii on populations of E. apisaon may be enhanced by the preservation of fragments of native vegetation surrounding Eucalyptus plantations.     

Expression, purification, and characterization of Bacillus subtilis cytochromes P450 CYP102A2 and CYP102A3: flavocytochrome homologues of P450 BM3 from Bacillus megaterium

The cyp102A2 and cyp102A3 genes encoding the two Bacillus subtilis homologues (CYP102A2 and CYP102A3) of flavocytochrome P450 BM3 (CYP102A1) from Bacillus megaterium have been cloned, expressed in Escherichia coli, purified, and characterized spectroscopically and enzymologically. Both enzymes contain heme, flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN) cofactors and bind a variety of fatty acid molecules, as demonstrated by conversion of the low-spin resting form of the heme iron to the high-spin form induced by substrate-binding. CYP102A2 and CYP102A3 catalyze the fatty acid-dependent oxidation of reduced nicotinamide adenine dinucleotide phosphate (NADPH) and reduction of artificial electron acceptors at high rates. Binding of carbon monoxide to the reduced forms of both enzymes results in the shift of the heme Soret band to 450 nm, confirming the P450 nature of the enzymes. Reverse-phase high-performance liquid chromatography (HPLC) of products from the reaction of the enzymes with myristic acid demonstrates that both catalyze the subterminal hydroxylation of this substrate, though with different regioselectivity and catalytic rate. Both P450s 102A2 and 102A3 show kinetic and binding preferences for long-chain unsaturated and branched-chain fatty acids over saturated fatty acids, indicating that the former two molecule types may be the true substrates. P450s 102A2 and 102A3 exhibit differing substrate selectivity profiles from each other and from P450 BM3, indicating that they may fulfill subtly different cellular roles. Titration curves for binding and turnover kinetics of several fatty acid substrates with P450s 102A2 and 102A3 are better described by sigmoidal (rather than hyperbolic) functions, suggesting binding of more than one molecule of substrate to the P450s, or possibly cooperativity in substrate binding. Comparison of the amino acid sequences of the three flavocytochromes shows that several important amino acids in P450 BM3 are not conserved in the B. subtilis homologues, pointing to differences in the binding modes for the substrates that may explain the unusual sigmoidal kinetic and titration properties.     

甘肃莲花山及其邻近地区大型真菌调查初报

本文报道了甘肃莲花山及其邻近地区的大型真茵１１７种,根据Ａｉｎｓｗｏｒｔｈ,Ｇ．Ｃ．系统（１９７３）,隶属于６０屑,２６科,２亚门,其中食用菌７０种,药用菌３７种,毒蘑菇２３种,菌根菌２４种,甘肃分布新纪录５０种。     

A simple model for the early events of quorum sensing in Pseudomonas aeruginosa: modeling bacterial swarming as the movement of an "activation zone"

Background  

Quorum sensing (QS) is a form of gene regulation based on cell-density that depends on inter-cellular communication. While there are a variety of models for bacterial colony morphology, there is little work linking QS genes to movement in an open system.     

Characterization of a birch (Betula pendula Roth.) embryogenic gene,BP8

We have isolated the birch homologue (BP8) for the carrot embryogenic gene DC8 by heterologous hybridization. The birch BP8 gene encodes a putative protein of 53 kDa, showing 52% sequence identity with the DC8 gene at the amino acid level. The putative BP8 protein contains 20 repeats of 11 amino acids and thus belongs to the group of LEA proteins isolated from such plants as carrot, cotton and wheat. Northern hybridization of mRNA isolated from birch cells representing different stages of somatic embryogenesis and non-embryogenetic material with a PB8 probe gave no signals, suggesting a low expression level of the BP8 gene.