Antagonistic effect of two isolates of Trichoderma harzianum against postharvest pathogens of tomato (Lycopersicon esculentum)

Pathogenicity test of all fungi (14 different isolates) isolated from both infected tomato fruits and the surface wash of other healthy fruits had different pathogenicity rates. The genus Rhizopus sp. was the most pathogenic one followed by Fusarium sp. Trichoderma harzianum isolates (T3 and T4) had a different pattern of antagonism against the tested pathogens. In dual plate test of the antagonistic action of T3 and T24 against the postharvest pathogens, clear zone size ranged between 1 and 4 and 3 and 6 mm by T3 and T24, respectively. The antagonists (T3 and T24) didn't show inhibition zone against Rhizopus sp., but they could overgrow it by 100% after 9 days of incubation. Mostly, all the other postharvest isolates showed high degree of overgrowth by T3 than T24. The two antagonists failed to overgrow Aspergillus species except for A. niger (3) which was overgrown by T3. Volatile and non-volatile metabolite tests indicated that mycelial growth of Penicillium stekii was significantly inhibited by T3 and T24 more than the other tested pathogens. The inhibition of A. niger (1) was 12% by non-volatile metabolites of T24 produced after 1 day incubation, and reached to 97% inhibition by the metabolites of 3 days. Interestingly, inhibition of Aspergillus sp. by volatile compounds of T3 and T24 was 2% and 20%, respectively, whereas the inhibition of the same pathogen by non-volatile compounds reached 75% and 87%, respectively. The results of slice assay clearly indicate that T. harzianum (T3 and T24) could provide a complete protection to tomato slices from the infection of the tested pathogens. After 3 days of incubation, Trichoderma suppressed the linear growth of these pathogens on tomato slices and the percentage of suppression was significant and ranged between 80 and 100%, except with Rhizopus sp. the suppression reached 33% only.     

Influence of carbon and nitrogen sources on antifungal metabolite production by bacterium associated with entomopathogenic nematode against Penicillium expansum

A specific symbiotic Bacillus sp. isolated from a rhabditid entomopathogenic nematode, Rhabditis (Oscheius) sp. was found to produce large number of bioactive compounds. The present study was conducted to determine the effect of carbon and nitrogen sources for the production of antimicrobial substances by Bacillus sp. The yield of the crude antimicrobial substances and antimicrobial activity against the test micro-organism also differed significantly when carbon and nitrogen sources in the fermentation media were changed. The antifungal activity was significantly high in yeast extract plus fructose (46.5?±?2.12?mm) followed by yeast extract plus maltose, beef extract plus fructose and meat infusion plus glucose. High pressure liquid chromatography analysis of the crude antimicrobial substances revealed different peaks with different retention time indicating that they produced different compounds. When the carbon source was not included in the fermentation media, the antimicrobial production was substantially reduced. The results indicate that carbon source in the fermentation media plays a vital role in the production of antifungal substances. It is concluded that yeast extract and fructose as nitrogen and carbon sources produced maximum activity, which can effectively control the blue mould caused by Penicillium expansum in apples and pears.     

ALTERATIONS WITH AGING OF THE ENDOCRINE AND NEUROENDOCRINE CIRCADIAN SYSTEM IN HUMANS

This was an open-label study in 19 children aged 9–13 years, weighing 27–44 kg, with bronchial asthma. Twenty-four-hour steady-state concentrations of theophylline and its metabolites 1,3-dimethyl uric acid, 3-methyl xanthine and 1-methyl uric acid were assessed after daily dosing of 600 mg (ca18 mg/kg/day) of the sustainedrelease theophylline micro-pellet sprinkle system BY158K, for 4 days. The dosing regimen used was an unequal twice-daily dose of 200 mg in the morning after breakfast and 400 mg in the evening after dinner. Twenty-four-hour peak expiratory flow (PEF) profiles were compared before treatment and at steady-state, along with lung function parameters after bronchial provocation. Mean values±SD (n=16) of the steady-state characteristics were C_min6.8±2.1 mg/1, C_max14.5±4.8 mg/1 and C_av10.S±2.9 mg/1, the plateau time was 11.7±4.8 hr and peak-trough fluctuation and swing were 72±21 and 118±52%, respectively. There was an excellent reproducibility of theophylline pre-dose levels at corresponding time points of the 24-hr sampling period [r=0.864 (p< 0.001)]. Mean values±SD of the 24 hr average serum metabolite levels were 0.9±0.2 mg/1 for 1, 3-dimethyl uric acid, 0.6±0.1 mg/1 for 3-methyl xanthine and 0.4±0.1 mg/1 for 1-methyl uric acid. Lung function (n=17) following bronchial provocation, improved in 10 children after theophylline treatment of 4 days, remained stable in 2 patients and deteriorated in 5 patients. Serum theophylline profiles and PEF profiles ran largely in parallel over the 24-hr period. Six children exhibited typical theophylline induced side-effects, headache (n=3), nausea (n=4), dizziness (n=l), vomiting (n=4), sleep disturbances (n=1), pallor (n=1) and tremor(n=1), necessitating in 3 children one dose omission/reduction (n=2) or subsequent dose reduction (n=1). It has been shown that a twice daily dosing regimen with unequal doses of anhydrous theophylline (BY158K) is well suited to this population of fast metabolisers. The patients were well protected throughout the day, including the critical early morning hours.     

Antiviral Effect of Theaflavins on Tobacco Mosaic Virus

Theaflavins, the oxidized products formed from tea leaf catechins during black tea fermentation, showed an antiviral activity on TMV. From the survey of the interactions of theaflavins with RNA and its related substances, it was presumed that theaflavins disturbed the replication cycle of TMV through binding to TMV-RNA.     

HPLC法检测苦杏仁苷及其酶解产物

本文建立了一个快速高效的HPLC方法同时检测苦杏仁苷及其4个体外酶解产物,色谱分析系统为安捷伦液相色谱系统,自动进样器,迪马ODS C18色谱柱(250 mm×4.6 mm,5μm),柱温25℃,流动相30%甲醇,检测波长210 nm,进样量10μL。结果表明,苦杏仁苷、phenyl-(3,4,5-trihydroxy-6-methyl-tetrahydro-pyran-2-yloxy)-acetonitrile、野樱花苷、苯甲醛和杏仁腈的保留时间分别为5.087、13.836、16.357、22.775和3.307 min。该HPLC方法的重现性好,精确度和准确度高,当柱温低于30℃、pH值介于6.0~7.0时该方法结果稳定、重现性好。     

Solid-State Fermentation Systems—An Overview

Abstract

Starting with a brief history of solid-state fermentation (SSF), major aspects of SSF are reviewed, which include factors affecting SSF, biomass, fermentors, modeling, industrial microbial enzymes, organic acids, secondary metabolites, and bioremediation. Physico-chemical and environmental factors such as inoculum type, moisture and water activity, pH, temperature, substrate, particle size, aeration and agitation, nutritional factors, and oxygen and carbon dioxide affecting SSF are reviewed. The advantages of SSF over Submerged Fermentation (SmF) are indicated, and the different types of fermentors used in SSF described. The economic feasibilities of adopting SSF technology in the commercial production of industrial enzymes such as amylases, cellulases, xylanase, proteases, phytases, lipases, etc., organic acids such as citric acid and lactic acid, and secondary metabolites such as gibberellic acid, ergot alkaloids, and antibiotics such as penicillin, cyclosporin, cephamycin and tetracyclines are highlighted. The relevance of applying SSF technology in the production of mycotoxins, biofuels, and biocontrol agents is discussed, and the need for adopting SSF technology in bioremediation of toxic compounds, biological detoxication of agro-industrial residues, and biotransformation of agro-products and residues is emphasized.     

Introduction of New Tools for Chemical Biology Research on Microbial Metabolites

Recently, high-throughput screening (HTS) has become the mainstream technique for drug discovery. Compounds that are synthesized by combinatorial chemistry might be more suitable than natural products to apply to HTS, because the purification procedure is a drawback of using natural products. Nevertheless, natural products remain an extremely important source of drugs. To overcome the demerits of natural products, we are constructing the RIKEN Natural Products Depository (NPDepo) that is focused primarily on microbial metabolites. In this review, I describe (i) engineering pathways for biosynthetic gene clusters of microbial metabolites, (ii) construction of fraction libraries of microbial metabolites, and (iii) the development of a new screening system using a chemical array and a protein library produced by GLORIA.     

Modified method for determination of sulfur metabolites in plant tissues by stable isotope dilution-based liquid chromatography–electrospray ionization–tandem mass spectrometry

A wide variety of sulfur metabolites play important roles in plant functions. We have developed a precise and sensitive method for the simultaneous measurement of several sulfur metabolites based on liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS) and ³⁴S metabolic labeling of sulfur-containing metabolites in Arabidopsis thaliana seedlings. However, some sulfur metabolites were unstable during the extraction procedure. Our proposed method does not allow for the detection of the important sulfur metabolite homocysteine because of its instability during sample extraction. Stable isotope-labeled sulfur metabolites of A. thaliana shoot were extracted and utilized as internal standards for quantification of sulfur metabolites with LC–MS/MS using S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), methionine (Met), glutathione (GSH), and glutathione disulfide (GSSG) as example metabolites. These metabolites were detected using electrospray ionization in positive mode. Standard curves were linear (r² > 0.99) over a range of concentrations (SAM 0.01–2.0 μM, SAH 0.002–0.10 μM, Met 0.05–4.0 μM, GSH 0.17–20.0 μM, GSSG 0.07–20.0 μM), with limits of detection for SAM, SAH, Met, GSH, and GSSG of 0.83, 0.67, 10, 0.56, and 1.1 nM, respectively; and the within-run and between-run coefficients of variation based on quality control samples were less than 8%.     

Multi‐factor climate change effects on insect herbivore performance

The impact of climate change on herbivorous insects can have far‐reaching consequences for ecosystem processes. However, experiments investigating the combined effects of multiple climate change drivers on herbivorous insects are scarce. We independently manipulated three climate change drivers (CO₂, warming, drought) in a Danish heathland ecosystem. The experiment was established in 2005 as a full factorial split‐plot with 6 blocks × 2 levels of CO₂ × 2 levels of warming × 2 levels of drought = 48 plots. In 2008, we exposed 432 larvae (n = 9 per plot) of the heather beetle (Lochmaea suturalis Thomson ), an important herbivore on heather, to ambient versus elevated drought, temperature, and CO₂ (plus all combinations) for 5 weeks. Larval weight and survival were highest under ambient conditions and decreased significantly with the number of climate change drivers. Weight was lowest under the drought treatment, and there was a three‐way interaction between time, CO₂, and drought. Survival was lowest when drought, warming, and elevated CO₂ were combined. Effects of climate change drivers depended on other co‐acting factors and were mediated by changes in plant secondary compounds, nitrogen, and water content. Overall, drought was the most important factor for this insect herbivore. Our study shows that weight and survival of insect herbivores may decline under future climate. The complexity of insect herbivore responses increases with the number of combined climate change drivers.