Growth of the extreme thermophile Sulfolobus acidocaldarius in a hyperbaric helium bioreactor

The relationship between pressure and temperature as it affects microbial growth and metabolism has been examined only for a limited number of bacterial species. Because many newly-discovered, extremely thermophilic bacteria have been isolated from pressurized environments, this relationship merits closer scrutiny. In this study, the extremely thermophilic bacterium, Sulfolobus acidocaldarius, was cultured successfully in a hyperbaric chamber containing helium and air enriched with 5% carbon dioxide. Over a pressure range of approximately 1-120 bar and a temperature range of 67-80 degrees C, growth was achieved in a heterotrophic medium with the air mixture at partial pressures up to 3.5 bar. Helium was used to obtain the final, desired incubation pressure. No significant growth was noted above 80 degrees C over the same range of hyperbaric pressures, or at 70 degrees C when pressure was applied hydrostatically. Growth experiments conducted under hyperbaric conditions may provide a means to study these bacteria under simulated in situ conditions and simultaneously avoid the complications associated with hydrostatic experiments. Results indicate that hyperbaric helium bioreactors will be important in the study of extremely thermophilic bacteria that are isolated from pressurized environments.     

Observations of Barophilic Microbial Activity in Samples of Sediment and Intercepted Particulates from the Demerara Abyssal Plain

To better understand the ecological significance of pressure effects on bacteria in the abyssobenthic boundary layer, experimental suspensions of sediments and sinking particulates were prepared from samples collected in boxcore and bottom-moored sediment traps at two stations (depth, 4,470 and 4,850m) in the Demerara abyssal plain off the coast of Brazil. Replicate samples were incubated shipboard at 3°C and at both atmospheric and deep-sea pressures (440 or 480 atm [4.46 × 10⁴ or 4.86 × 10⁴ kPa]) following the addition of [¹⁴C]glutamic acid (<10 μg liter⁻¹) or yeast extract (0.025%) and the antibiotic nalidixic acid (0.002%). In seven of the eight samples supplemented with isotope, a barophilic microbial response was detected, i.e., substrate incorporation and respiration were greater under in situ pressure than at 1 atm (101.3 kPa). In the remaining sample, prepared from a sediment trap warmed to 24°C before recovery, pressure was observed to inhibit substrate utilization. Total bacterial counts by epifluorescence microscopy decreased with depth in each sediment core, as did utilization of glutamic acid. Significant percentages of the total bacterial populations in cold sediment trap samples (but not the prewarmed one or any boxcore sample) were abnormally enlarged and orange fluorescing after incubation with yeast extract and nalidixic acid under deep-sea conditions. Results indicated that in the deep sea, barophilic bacteria play a predominant role in the turnover of naturally low levels of glutamic acid, and the potential for intense microbial activity upon nutrient enrichment is more likely to occur in association with recently settled particulates, especially fecal pellets, than in buried sediments.     

红旗泡水生植物群落结构与功能的研究

红旗泡是松嫩平原上的水草型湖泊,１９７２年由引嫩干渠补入嫩江水,使其成为大庆市主要水源地和渔业基地。该湖水生植被分布面积大,覆盖近１／２的水面。本文分析了芦苇,狭叶香蒲和稗等单优群落的结构与分布,并统计了混合群落的数量特征。随着油田开发,大庆地区的水体均受到不同程度的污染;因红旗泡水生植物资源丰富且其具清除油污、吸附重金属和沉降悬浮物等净化功能,故使其成为大庆地区水质最好和鱼产量最高的湖泊。     

含人口迁移的性传染病模型

本文研究一类含人口迁移的性传染病模型,应用摄动方法和定性方法研究平衡点的稳定性和迁移率的影响。普举例说明。     

南亚热带森林几种乔木种子萌发和幼苗生长观察

本文对香椿（Ｔｏｏｎａｓｉｎｅｎｓｉｓ（Ａ．Ｊｕｓｓ．）Ｒｏｅｍ．）、木蝴蝶（Ｏｒｏｘｙｌｕｍｉｎｄｉｃｕｍ（Ｌ．）Ｖｅｎｔ．）、扁斗青冈（ＱｕｅｒｃｕｓｈｕｉＣｈｕｎ）、泡桐（Ｐａｕｌｏｗｎｉａｆｏｒｔｕｎｅｉ（Ｓｅｅｍ．）Ｈｅｍｓｌ）罗浮柿（ＤｉｏｓｐｙｒｏｓｍｏｒｒｉｓｉａｎａＨａｎｃｅ）、枳（ＢｅｒｃｈｅｍｉａｄｕｌｃｉｓＴｈｕｎｂ．）等南亚热带森林乔木种子萌发和幼苗生长进行观察．香椿、扁斗青冈、罗浮柿种子在轻阴（５５％光）条件下萌发率最高,分别为７０％、９０％、３０％,木蝴蝶种子在重阴（３８％光）条件下萌发率最高,为８０％,枳种子在光照条件下萌发率最高,为１５％．阳性树种香椿、木蝴蝶、泡桐、枳幼苗生长速度较快,属速生型树种,其幼苗在光照条件下生长速度最快,森林中树种扁斗青冈、罗浮柿幼苗生长速度较慢,属慢生型树种,其幼苗在轻阴条件下生长较好．随着施肥量的增加,幼苗生长速度明显提高．     

Microsomal and cytosolic cytochrome P450 mediated benzo(a)pyrene hydroxylation in Pleurotus pulmonarius

Summary Microsomal and soluble fractions of Pleurotus pulmonarius exhibited a reduced carbon monoxide difference spectrum with P450 maxima at 448nm and 450–452nm respectively. Substrate induced Type I spectra were observed on addition of benzo(a)pyrene to both fractions. Benzo(a)pyrene hydroxylation was measured using the aryl hydrocarbon hydroxylase assay and was observed to be P450 dependent as indicated by carbon monoxide inhibition together with the substrate binding characteristics. The activity of the fractions were observed to give K_m of 200mM and 660mM and V_max of 1.25 nmol/min/nmol P450 and 0.57 nmol/min/nmol P450 for the microsomal and cytosolic fractions respectively.     

河南新乡地区儿童头面部测量

本文对河南省新乡地区汉族儿童（４－１３岁）头面部进行了测量,比较和分析了儿童体质发育与年龄增长的关系,据儿童头面部各指数数值大小分型,确定该地区汉族儿童面部的形态为：圆头型、高头型、狭头型、狭面型、狭鼻型。     

Effects of Hydrostatic Pressure on Growth of Hyperthermophilic Archaebacteria from the Juan de Fuca Ridge

Two new strains (AL1 and AL2) of hyperthermophilic, sulfur-reducing, heterotrophic archaebacteria from high-temperature (350°C) vents on the Juan de Fuca Ridge were highly barotolerant at their optimal growth temperatures (90 and 100°C, respectively). A trend towards barophily at pressures greater than those encountered in situ at the sea floor was demonstrated for the more extremely thermophilic strain (AL2), implying an ability to thrive in (unexplored) habitats well below accessible vent formations.     

北长山岛森林乔木层碳储量及其影响因子

人工林是庙岛群岛典型的陆地生态系统的组成部分,对维护海岛地区生态环境具有重要作用。采用现有生物量相对生长方程和样地调查数据相结合的方法,以庙岛群岛中北长山岛为研究区,对海岛黑松纯林与黑松×刺槐混交林两种林型的碳储量进行了估算,并分析了土壤质地及其理化性质对海岛乔木层碳储量的影响。结果表明:黑松乔木层平均碳储量为84.00 t/hm²,接近于世界平均水平(86.00 t/hm²);黑松×刺槐混交林乔木层平均碳储量为29.60 t/hm²,高于山东省乔木层的平均碳储量(27.62 t/hm²)。应用因子分析法研究影响乔木层碳储量的主要因子,结果表明:土壤质地、pH值、含水量及含盐量是影响海岛乔木碳储量重要的影响因子。北长山岛土壤全氮、总磷、土壤有机质、碳氮比等其他理化性质对乔木层碳储量影响不是非常明显。