Variation in the incidence of H2-oxidizing chemolithotrophic bacteria in rice grown under different cultivation conditions

Summary The incidence of H₂-oxidizing chemolithotrophic bacteria associated with rice grown under continuous wetland, upland, and rainfed wetland conditions was studied by¹⁴C-autoradiographic technique in a neutral soil at IRRI (Maahas) and an acid rainfed wetland soil (Luisiana).In Maahas soil, H₂-oxidizing chemolithotrophic bacteria were not detected in the endorhizosphere, rhizosphere, and nonrhizosphere soil of rice grown under dryland conditions. Under continuously flooded conditions a very large population of these bacteria were found in the endorhizosphere but not in the oxidized and reduced soil.A very low population of these bacteria were found in the endorhizosphere and basal culm of rice grown under rainfed wetland conditions at Luisiana. Bacteria isolated from Maahas wetland rice and inoculated to rice seedling planted in Luisiana soil failed to establish.Both Maahas and Luisiana soils consumed externally supplied H₂ and produced H₂ and CH₄ almost at the same rate when they were amended with rice straw or sucrose. This paper discusses possible causes of variation in the number of these bacteria and their distribution in rice grown under different cultural and soil conditions.     

Sensitivity of Proteus hauseri bacteria to chemotherapeutic preparations depending on the cultivation conditions and on the composition of the nutrient medium]

Sensitivity of 227 Proteus strains isolated from patients was studied comparatively using the agar-diffusion method (disks) and the method of serial dilutions. Marked differences in the numbers of the strains resistant to benzylpenicillin and chloramphenicol were found with the above methods. It was shown that the ingredients of Ploskirev's medium significantly (by 2.8--13.5 times) inhibited the antibacterial activity of streptomycin, neomycin, monomycin, kanamycin, ampicillin and nalidixic acid and had practically no effect on the activity of benzylpenicillin, chloramphenicol and furazolidone. The values of the MIC of the drugs used in the experiment with liquid media correlated with those obtained with Sabouro's medium, which provided recommendation of the latter for determination of Proteus sensitivity by the method of serial dilutions in the solid medium, Cultivation of Proteus at a temperature of 40 degrees C resulted in a decrease of the resistance to most of the drugs tested by (by 3--12.4 times).     

Effect of the culture medium composition on bacitracin synthesis and sporulation in Bacillus lichenformis 28 KA

The effect of the culture medium composition on the bacitracin synthesis and sporulation in Bacillus licheniformis 28 KA was being studied. During the producer's growth on a medium with tripton a biphasic pattern of the process was observed, i.e. a rapid growth of the bacterial biomass was accompanied by the production of insignificant amounts of the antibiotic. The maximum efficiency of the antibiotic synthesis coincides with the end of the exponential growth phase and the onset of sporification. The efficiency of sporification amounts up to 95% when the above mentioned medium is used. The substitution of glutamate for trypton results in a dramatic deceleration of the bacterial growth and biomass accumulation, and the process of the antibiotic biosynthesis ceases to be biphasic, i. e. the antibiotic is synthesized during the trophophase. Under the conditions when the antibiotic production drops to zero by the middle of the exponential growth phase, sporulation is virtually suppressed.     

培养基及培养条件对冬虫夏草菌固体发酵产分生孢子的影响

为获得冬虫夏草菌固体发酵产分生孢子的最优工艺,以野生分离的冬虫夏草菌为材料,对其固体发酵产分生孢子的培养基及培养条件进行了研究。试验结果表明：泥炭土为最佳基础培养基,该培养基中冬虫夏草菌气生菌丝生长一般,但产分生孢子最多,可达4.2×10³个/g;泥炭土培养基中添加0.1‰ IAA（吲哚乙酸）、0.1‰ IBA（吲哚丁酸）和0.1‰ NAA（萘乙酸）能促进冬虫夏草菌气生菌丝的生长和分生孢子的产生,其分生孢子达8.1×10³个/g;该基础培养基中,冬虫夏草菌于18℃培养30d后,在10℃、相对湿度45%、蓝光照射进行诱导,分生孢子可达1.0×10⁴个/g。本研究建立了一种大量获取冬虫夏草菌分生孢子的方法,为冬虫夏草繁育奠定了基础。     

Optimization of cultivation medium composition for isoamylase production

Summary The medium composition for production of isoamylase by Pseudomonas amyloderamosa JD210 was optimized using response surface methodology. The factors chosen for optimization were maltose, soybean protein hydrolysate (SPH), isoleucine, proline, KH₂PO₄ and MgSO₄. Fractional factorial designs (FFD) and the path of steepest ascent were effective in searching for the major factors and optimum medium composition. By a 2^6–1 FFD, supplementary isoleucine was shown to have a negative effect on enzyme production. The effects of the other five factors were further investigated by a central composite design and the optimum composition was found to be 1.10% maltose, 0.13% SPH, 0.15% proline, 0.38% KH₂PO₄, and 0.05% MgSO₄. When the strain was cultivated in the optimum medium, enzyme production increased 60% compared with ordinary medium. Proline was verified as being a significant factor in promoting enzyme production.     

培养条件对茄链格孢产孢的影响

茄链格孢Alternaria solani在体外培养条件下不产生或产生极少量的分生孢子。研究了培养基、菌丝损伤、紫外线照射和温度变化对7个茄链格孢菌株产孢的影响,发现这些处理方法对供试大多数菌株的产孢都有显著影响,确立了茄链格孢大量产孢的最优条件。利用优化后的条件对160株采自不同地区的茄链格孢进行体外诱导产孢,发现120株可大量产孢,占总数的75%,产孢量为1.26×104–5.03×104个/cm2。     

两步培养法测定真菌产孢营养需求

生防真菌产孢条件的测定一般都是通过连续培养方法,即在同一种限定培养基上完成其生长和产孢过程。文中我们提出分离真菌的生长和产孢阶段,测定产孢营养需求的两步培养新方法。6种生防真菌首先在平板上进行营养生长,然后转移至营养成分和浓度确定的新鲜培养基中继续产孢过程来测定菌株产孢阶段实际营养需求。通过与连续培养方法比较,发现只有淡紫拟青霉Paecilomyces lilacinus、金龟子绿僵菌Metarhizium anisopliae二者产孢条件一致,而厚孢轮枝菌Pochonia chlamydosporia、球孢白僵菌Beauveria bassiana、蜡蚧轮枝菌Lecanicillium lecanii、绿色木霉Trichoderma viride菌株产孢的营养条件存在显著的差异。基于这一方法,确定了绿色木霉最佳产孢条件,即起始碳浓度2g C/L,碳氮比10:1,最佳碳氮源组合纤维二糖和酵母浸膏,为真菌生防制剂生产调控提供了依据。     

Nickel requirement for chemolithotrophic growth in hydrogen-oxidizing bacteria

In a comparative study the requirement of several strains of autotrophic hydrogen-oxidizing bacteria for nickel was examined. Autotrophic growth was studied both in liquid media, previously freed from trace metals; and on solidified media, using a plate diffusion assay. The latter assay was based on the observation that EDTA causes complete inhibition of autotrophic growth on agar medium as a result of nickel deficiency. Nickel was shown to be required as a trace element in five strains of Alcaligenes eutrophus, in two strains of Xanthobacter autotrophicus, in Pseudomonas flava, in Arthrobacter spec. 11X and in strain 12X. In these bacteria nickel was not replaceable by cobalt, copper, manganese or zinc ions. No significant nickel requirement was detected by these methods, however, for Paracoccus denitrificans and Nocardia opaca 1b.     

漏斗多孔菌液体菌种培养基及其栽培条件

为实现漏斗多孔菌资源化利用,设计单因素试验,以菌丝生物量、菌球密度和菌球直径为指标,获得漏斗多孔菌Polyporus arcularius液体菌种培养基配方为马铃薯(去皮)200g、玉米粉20.0g、蛋白胨5.0g、KH2PO43.0g、 K2HPO41.0g,MgSO4·7H2O 1.5g,初始pH 5.0,并优化培...     

The heat shock response in meso- and thermoacidophilic chemolithotrophic bacteria

Abstract The heat shock response was studied in a chemolithotrophic thermoacidophilic archaebacterium Sulfolobus acidocaldarius (shifted from 70° to 85°C) and a mesoacidop0ilic microorganism Thiobacillus ferrooxidans (from 30° to 41°C). When transferred from their normal growth temperature to the stress temperature, cells showed a decrease in the incorporation of Na₂¹⁴CO₃ into proteins, and at the same time, the synthesis of a specific subset of heat shock proteins was observed. Ethanol (4%) at 30°C, also caused a response similar to the heat shock upon T. ferrooxidans cells, whereas Sulfolobus cells at 70°C did not incorporate radioactive CO₂ in the presence of ethanol, apparently being damaged by the organic solvent.     

生物破乳剂产生菌混合培养及其发酵条件的优化

【目的】对菌株L1和XH1的混合发酵条件进行优化,为混合菌发酵生物破乳剂的实际生产和应用提供理论依据。【方法】利用响应面实验(RSM)的中心组合旋转设计方法(CCRD)针对混合菌的发酵条件进行优化,通过对模型乳状液进行破乳实验,以排油率作为发酵液破乳效能的评价标准。【结果】经模型的分析与验证,确定最佳发酵条件为：种子液比例(L1:XH1)为3:2,葡萄糖投加时间为第4天,投加葡萄糖后再培养21 h,液体石蜡含量3.6% (体积比)。【结论】与破乳菌XH1和L1单独培养相比,经混合培养后获得复合生物破乳剂具有投加量少、破乳接触时间短的优势。同时双株破乳菌复配培养有效地提高了培养基中主要营养物质的利用率,减少了对底物的浪费。