Conjugation of yeast mannans with protein employing cyanopyridinium agent (CDAP) – an effective route of antifungal vaccine preparation

The possibility of using 1-cyano-4-dimethylaminopyridinium tetrafluoroborate (CDAP) for activation of saccharide hydroxyl groups (instead of hazardous cyanogen bromide) is examined with cell-surface mannans of the yeasts Candida albicans Candida tropicalis,Candida lambicaand galactoglucoxylomannan of Cryptococcus laurentii.Direct conjugation with human serum albumin yielded soluble products with increased molecular size in comparison with the original polysaccharides. Immunodiffusion experiments revealed that conjugation did not affect the immunospecificity of the antigen epitope.     

Ethanolic extract of mango (Mangifera indica L.) malformed inflorescence as effective antifungal agent

Mango (Mangifera indica L.) suffers from floral and vegetative malformation and crop production is seriously affected. The anti-fungal activity of ethanolic extract of malformed mango inflorescence was observed at different concentrations (1000, 2000, 3000, 4000 and 5000 μl/ml) against 10 fungi, viz., Ustilago cynodontis, Cercospora cajani, Sphaerotheca sp., Cercospora sp., Alternaria solani, Bipolaris sp., Helminthosporium sp., Curvularia sp., Fusarium udum and Alternaria cajani. Spore germination of most of the fungi was inhibited at 5000 μg/ml. Some of them were also susceptible at 3000 or 4000 μg/ml concentration. Analysis of phenolic acids by high performance liquid chromatography (HPLC) showed 18 peaks in the extract, but only four could be identified, viz., capachin, gallic, benzoic and cinnamic acids. Because of the high efficacy of ethanolic extract of malformed mango inflorescence, its use under field conditions to control some plant diseases has been suggested.     

Structure-based drug discovery of carbonic anhydrase inhibitors

Inhibition of the metalloenzyme carbonic anhydrase (CA; EC 4.2.1.1) has pharmacologic applications in the field of anti-glaucoma, anti-convulsant and anti-cancer agents. But recently, it has also emerged that these enzymes have the potential for designing anti-infective drugs (anti-fungal and anti-bacterial agents) with a novel mechanism of action. Sulphonamides and their isosteres (sulphamates/sulphamides) constitute the main class of CA inhibitors (CAIs), which bind to the metal ion from the enzyme active site. Recently, the dithiocarbamates (DTCs), possessing a similar mechanism of action, were reported as a new class of inhibitors. These types of CAIs will be discussed in detail in this review. Novel drug design strategies have been reported ultimately based on the tail approach for obtaining sulphonamides/DTCs, which exploit more external binding regions within the enzyme active site (in addition to coordination to the metal ion), leading thus to isoform-selective compounds. Most of the promising data have been obtained by combining x-ray crystallography of enzyme-inhibitor adducts with novel synthetic approaches for generating chemical diversity. Whereas sulphonamide – NO donating hybrid drugs were reported as effective anti-glaucoma agents, most of the interesting new inhibitors were designed for inhibiting specifically the tumour-associated isoforms CA IX and XII, validated targets for imaging and treatment of hypoxic tumours. Promising compounds that inhibit CAs from bacterial and fungal pathogens, of the DTC and carboxylate types, will be also reviewed.     

Varietal difference in antifungal activity of some species of Agave

Crude leaf extracts of different Agave species were eluted out with the help of 80% methanol for their antifungal activity. The activity of A. americana, A. ferox, A. montana, A. marginata, and A. scabra were evaluated against brown rot fungi Postia placenta, the causal agent of wood decay of some economically important plants using a media poising method. The percent inhibition of hyphal growth was measured after the seventh day of incubation. A. montana shows the highest percent inhibition, 69.31%, of hyphal growth. These data suggested that the different Agave species analyzed have potential as antifungal agents with a broad range of activity. In the future they may be used as biocontrol agents to cure plant diseases without harming them.     

多功能菌群混合施用的生态效应

从蔬菜地黄瓜根围土壤中经分离筛选,得到两个对黄瓜枯萎病菌(Fusarium oxysporum f.sp.cucumerinum)有抑制作用,并能明显促进黄瓜生长的菌株ZJY-1(Brevibacillus brevis)和ZJY-116(Bacillus subtilis).将这两菌株与一株毒死蜱降解菌DSP3(Alcaligenes faecali)按照不同组合处理黄瓜种子,以研究多功能菌群在环境中发挥生态效应的可行性.结果表明,这两株具有生防和促生功能的菌株与DSP3按不同组合混合后,对黄瓜的防病促生作用均不受影响.同时对黄瓜根围土中毒死蜱含量检测分析发现,DSP3与这两株细菌混和施用后其降解率与单独施用相比没有明显差异.实验初步证明,不同功能的菌株混合施用后可以发挥其生态效应.     

Comparison of methods to detect resistance of Penicillium expansum to thiabendazole

Aims:  Because of the lack of a standard method, the aim of this work is to evaluate the suitability of the broth microdilution method CLSI M38-A in determining the resistance level of some Penicillium expansum isolates to thiabendazole (TBZ). The ability of the isolates to produce patulin (PAT) and citrinin (CIT) has been also assessed.
Methods and Results:  Penicillium expansum isolates (128) were assayed (apples, pears, grapes and five reference strains). It was observed that 69·4% of the strains isolated from apples and pears were resistant to TBZ. Sensitive isolates were inhibited at 0·25–0·5 μg ml⁻¹ whilst resistant isolates still grew at 512 μg ml⁻¹. PAT was produced by all P. expansum isolates. CIT was detected in 98·8% of TBZ-resistant isolates and in 89·1% of the TBZ-sensitive isolates.
Conclusions:  The preliminary screening method combined with the adaptation of the method CLSI M38-A, can be a good strategy to be used in assessing the in vitro activity of TBZ against a large number of isolates.
Significance and Impact of the Study:  The proposed methodology can be a contribution to the standardization of susceptibility tests to fungicides against P. expansum.     

Rational design of organophosphorus hydrolase with high catalytic efficiency for detoxifying a V-type nerve agent

V-type nerve agents, known as VX, are organophosphate (OP) compounds, and show extremely toxic effects on human and animals by causing cholinergic overstimulation of synapses. The bacterial organophosphorus hydrolase (OPH) has attracted much attention for detoxifying V-type agents through hydrolysis of the P–S bond. However, low catalytic efficiency of OPH has limited the practical use of the enzyme. Here we present rational design of OPH with high catalytic efficiency for a V-type nerve agent. Based on the model structure of the enzyme and substrate docking simulation, we predicted the key residues that appear to enhance the access of the substrate to the active site of the enzyme, and constructed numerous OPH mutants. Of them, double mutant, L271/Y309A, was shown to exhibit a 150-fold higher catalytic efficiency for VX than the wild-type.