Search for Insect Neuroactive Substances Using an Electrophysiolofical Method

A simple and rapid bioassay was developed to search for novel insect neuroactive substances.This method was based on the electrophysiological response of the metathoracic legnerve of Periplaneta americana.Using this assay,41 methanol extracts of Kenyan plant and 15 methanol extracts of Indonesia plants were tested to show various activities.Several compounds were isolated from these methanol extracts with the guidance of the activity increasing spontaneous-impulse frequencies.地球規模での環境問題に関心が高まりつつある現在、病害虫防除のための薬剤に求められているのは、ターゲットに対する強力な効果はもちろんのこと、高い選択性と適度な生分解性である。そのような優れた特性をもつ薬剤のリード化合物となる生理活性物質を自然界から見出そうと、これまでに数多くの試みがなされてきた。その手段となるのが生物試験であり、新たな生物試験の開発が新規の活性化合物の発見につながることもある。そこで著者は、昆虫の神経を作用点とする天然生理活性物質を探索するための新たな生物試験法の開発を試みた。昆虫神経作用物質は、その効果が強力かつ速効性であることが多い点、また、植物や微生物に対し影響を及ぼしにくい点で有効なリード化合物として期待される。さらに、昆虫と哺乳動物とでは代謝に多くの違いがあるため、昆虫には強力な毒性を示しても人畜への毒性は低いことが多い。天然ピレスロイドは、このような昆虫神経作用物質の長所を合わせ持つ、理想的な例であった。自然界には、ピレスロイドと同等、またはそれ以上に優れた防除剤となりうる昆虫神経作用物質が存在するはずである。しかし、昆虫神経作用物質探索のための生物試験法はまだ一般的ではない。神経活動の観察には通常、電気生理学的手法が用いられているが、細かい作業と長い時間を要すものが多く、薬剤の作用機構の解明など、生理学的研究の手段とはなっても、スクリーニングのための生物試験として確立されたものはほどんど知られていない。著者はワモンゴキブリ（Periplanata americana)の後肢神経系を用いて、昆虫神経作用物質探索のための簡便で迅速な生物試験法を開発した。また、この試験を指標としてケニヤ産植物およびインドネシア産植物のメタノール抽出物から、いくつかの活性化合物を単離した

An Analytical Method of lnophyllums A,B,C,D,E,and P,Anti - HIV Constituents of Calophyllum inophyllum by HPLC

In order to optimize cell culture conditions for producing inhibitors of HIV reverse transcriptase isolated from Calophyllum , inophyllum , a rapid and accurate anaalytical method for determining the quantity of the inhibitors, inophyllums A , B , C , D , E , and P was desired . We have established a quantitative analytical method using HPLC ,together with LCMS .最近、抗HIV活性化合物として注目されているCalophyllum inophyllumの葉の成分、inophyllum化合物を細胞培養で生産するためには、培養条件検討時に用いる当各成分の迅速かつ正確な分析法が必要である。本研究では、著者らの一人が以前に単離したinophyllum化合物のHPLC上の溶出位置を決定できることを示した

Use of wood vinegar to enhance 5-aminolevulinic acid production by selected Rhodopseudomonas palustris in rubber sheet wastewater for agricultural use

AbstractThis study aimed to produce inexpensive 5-aminolevulinic acid (ALA) in a non-sterile latex rubber sheet wastewater (RSW) by Rhodopseudomonas palustris TN114 and PP803 for the possibility to use in agricultural purposes by investigating the optimum conditions, and applying of wood vinegar (WV) as an economical source of levulinic acid to enhance ALA content. The Box–Behnken Design experiment was conducted under microaerobic-light conditions for 96h with TN114, PP803 and their mixed culture (1:1) by varying initial pH, inoculum size (% v/v) and initial chemical oxygen demand (COD, mg/L). Results showed that the optimal condition (pH, % inoculum size, COD) of each set to produce extracellular ALA was found at 7.50, 6.00, 2000 for TN114; 7.50, 7.00, 3000 for PP803; and 7.50, 6.00, 4000 for a mixed culture; and each set achieved COD reduction as high as 63%, 71% and 75%, respectively. Addition of the optimal concentration of WV at mid log phase at 0.63% for TN114, and 1.25% for PP803 and the mixed culture significantly increased the ALA content by 3.7–4.2times (128, 90 and 131μM, respectively) compared to their controls. ALA production cost could be reduced approximately 31times with WV on the basis of the amount of levulinic acid used. Effluent containing ALA for using in agriculture could be achieved by treating the RSW with the selected ALA producer R. palustris strains under the optimized condition with a little WV additive

The use of rice straw broth as an appropriate medium to isolate purple nonsulfur bacteria from paddy fields

Abstract The aims were to explore an appropriate isolating medium for obtaining purple nonsulfur bacteria (PNSB) for use as biofertilizers in saline paddy fields and to obtain pure cultures. We therefore chose a defined isolating medium containing 0.25% NaCl, (Glutamate-Acetate broth, GA) and a rice straw broth to compare them for numbers of PNSB obtained, time to obtain pure cultures, diversity and costs. A total of 30 water and 30 sediment samples were collected from saline paddy fields in southern Thailand and used to isolate PNSB in both the isolating media. Based on 60 samples and a period of 13 days incubation under anaerobic light conditions, a greater number of samples produced PNSB growth in GA broth after only day 3; however, after that the rice straw broth provided about a 2 fold increase in the number of samples that produced PNSB growth. Colonies isolated from GA broth required a significantly higher number of repeated streaking to obtain a pure culture (average 3.5) than those from rice straw broth (average 2.7) and the latter medium also produced significantly (P < 0.05) more isolates per sample. Sixty samples of water and sediment, from rice paddies with salinity (average, 3.43 \ub1 0.67 mS/cm) and slight acidity (average, pH 5.84 \ub1 0.42) provided 62 PNSB isolates by GA broth and 210 isolates by rice straw broth, and rice straw broth also produced a greater prevalence of PNSB. Estimates of the costs based on current prices of media, Gas Pak and electricity to obtain PNSB with the use of GA broth was roughly 6 times higher than for the rice straw broth

Novel Cyclic Dipeptide Dehydrogenase and Assay Method for Activity

The cell-free extract prepared from cells of an albonoursin-producing actinomycete Streptomyces sp. KO2388 was found to catalyze the dehydrogenation of cyclo (L-Phe-L-Leu) (CFL) to albonoursin. This is the first report for the dehydrogenation at the α,β-positions of amino acid residues. The simple method for determining the dehydrogenation activity was devised by measuring the increase in UV absorption of the reaction mixture at 317nm, λmax(ε25,400) of albonoursin, where CFL had no absorption. Phenazine methosulfate was the most active cofactor for the dehydrogenation among several hydrogen acceptors.アルボノルシン生産菌、Streptomyces sp. KO2388株の無細胞抽出液が、cyclo(L-Phe-L-Leu)からアルボノルシンへの脱水素反応を触媒することを明らかにした。アミノ酸残基のα,β-位での脱水素反応を酵素レベルで明らかにしたのはこの報告が初めてである。本反応の簡便な測定法として、基質cyclo(L-Phe-L-Leu)には認められない。アルボノルシンの特異的な317nmにおける紫外吸収の増加を測定する方法を考案した。本方法を用いて数種の水素受容体を試験したところ、フェナジンメトサルフェートが最も有効であると判った

Tectona grandis の母植物体には少量しか、あるいは全然存在しない抗菌性トリテルペン酸の動植物細胞懸濁培養による生産

The callus culture of Tectona grandis was previouly reported by us to produce five antibacterial acids which occurred only in very small amounts or were not detected in the native plant. This paper shows the production of these antibacterial compounds in much higher by cell suspension culture of the plant.著者らは以前、Tectona grandis のカルスが、母植物には少量しか、あるいは全然存在しない抗菌性トリテルペン酸を相当量することを報告した。本報は、確立した細胞懸濁培養系では、これらの抗菌性トリテルペン酸の生産性がカルス培養の100～200倍にも上昇することを述べ、これらの抗菌性化合物を細胞懸濁培養で生産できることを示した

Effects of 5-aminolevulinic acid (ALA)-containing supernatants from selected Rhodopseudomonas palustris strains on rice growth under NaCl stress, with mediating effects on chlorophyll, photosynthetic electron transport and antioxidative enzymes

Background: Rice is globally one of the most important food crops, and NaCl stress is a key factor reducing rice yield. Amelioration of NaCl stress was assessed by determining the growth of rice seedlings treated with culture supernatants containing 5-aminolevulinic acid (ALA) secreted by strains of Rhodopseudomonas palustris (TN114 and PP803) and compared to the effects of synthetic ALA (positive control) and no ALA content (negative control). Results: The relative root growth of rice seedlings was determined under NaCl stress (50 mM NaCl), after 21 d of pretreatment. Pretreatments with 1 \u3bcM commercial ALA and 10X diluted culture supernatant of strain TN114 (2.57 \u3bcM ALA) gave significantly better growth than 10X diluted PP803 supernatant (2.11 \u3bcM ALA). Rice growth measured by dryweight under NaCl stress ordered the pretreatments as: commercial ALA > TN114 > PP803 > negative control. NaCl stress strongly decreased total chlorophyll of the plants that correlated with non-photochemical quenching of fluorescence (NPQ). The salt stress also strongly increased hydrogen peroxide (H2O2) concentration in NaCl-stressed plants. The pretreatments were ordered by reduction in H2O2 content underNaCl stress as: commercial ALA > TN114 > PP803 > negative control. The ALA pretreatments incurred remarkable increases of total chlorophyll and antioxidative activities of catalase (CAT), ascorbate peroxide (APx), glutathione reductase (GR) and superoxide dismutase (SOD); under NaCl stress commercial ALA and TN114 had generally stronger effects than PP803. Conclusions: The strain TN114 has potential as a plant growth stimulating bacterium that might enhance rice growth in saline paddy fields at a lower cost than commercial ALA

Characterization of the antiyeast compound and probiotic properties of a starter Lactobacillus plantarum DW3 for possible use in fermented plant beverages

Lactobacillus plantarum DW3 produced antifungal compounds that inhibited the growth of Rhodotorula mucilaginosa DKA, contaminating yeast in fermented plant beverages (FPBs) and various potential human pathogens. Phenyllactic acid (PLA) identified by gas chromatography- mass spectrometry (GC-MS) was produced at 31 mg/L PLA in MRS medium and 5 mg/ml inhibited growth of the target yeast in vitro by 90%. Other inhibitors were also present but not specifically identified. Results of in vitro tests showed that DW3 also had probiotic properties as it survived various human biological barriers resistance to pH 3, bile salts, growth without vitamin B12 and the presence and absence of oxygen. Its inhibitory effect against food borne pathogenic bacteria and spoilage organisms was higher than that found for a commercial strain Lactobacillus casei R. An acute oral toxicity test on ICR mice at a high single dose of either 109 and 1012 cells per mouse for 14 days showed that DW3 had no adverse effect on the general health status and there was no evidence of bacteremia. Mice fed DW3 had a reduced weight gain compared to the control. No significant difference (p > 0.05) was found for the spleen weight index (SWI) among the treatment and control groups whereas there was a significant difference (p < 0.05) for the liver weight ratio (LWR) in a group fed with 1012 cells per mouse when compared with the control group