Structural aspects of Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] tuberculate ectomycorrhizae

Summary Tubercles of Pseudotsuga menziesii consisted of clusters of ectomycorrhizae surrounded by a peridiumlike rind. Energy dispersive spectroscopy demonstrated that crystals found in the zone of loose hyphae extending from the inner rind to the mantle of each root probably contain calcium oxalate. Inner mantle and Hartig net hyphae showed a labyrinthine branching pattern and stored carbohydrates and protein. The Hartig net formed up to inner cortical cells which had thickened, darkly stained walls. Bacteria were located either along with hyphae within the rind or as colonies on the surface of the tubercle.     

Randomised controlled trial of short term treatment to eradicate Helicobacter pylori in patients with duodenal ulcer.

OBJECTIVE--To determine whether one week''s drug treatment is sufficient to eradicate Helicobacter pylori in patients with duodenal ulcer. DESIGN--Single blind, randomised controlled trial. SETTING--Specialised ulcer clinic in a teaching hospital. PATIENTS--155 patients with H pylori and a duodenal ulcer verified endoscopically which had either bled within the previous 24 hours or was causing dyspepsia. INTERVENTIONS--Patients were allocated randomly to receive either omeprazole for four weeks plus bismuth 120 mg, tetracycline 500 mg, and metronidazole 400 mg (all four times a day) for the first week (n = 78), or omeprazole alone for four weeks (n = 77). Further endoscopy was performed four weeks after cessation of all drugs. MAIN OUTCOME MEASURES--Presence or absence of H pylori (by urease testing, microscopy, and culture of antral biopsy specimens), duodenal ulcer, and side effects. RESULTS--Eradication of H pylori occurred in 70 (95%) patients taking the four drugs (95% confidence interval 86% to 97%) compared with three (4%) patients taking omeprazole alone (1% to 11%). Duodenal ulcers were found in four (5%) patients taking the four drugs (2% to 12%) and in 16 (22%) patients taking omeprazole alone (14% to 32%). Mild dizziness was the only reported side effect (six patients in each group) and did not affect compliance. CONCLUSIONS--A one week regimen of bismuth, tetracycline, and metronidazole is safe and effective in eradicating H pylori and reduces the number of duodenal ulcers four weeks after completing treatment.     

Metabolism of [4-14C]estrone in hamster and rat hepatic and renal microsomes: species-, sex- and age-specific differences.

The metabolism of [4-14C]estrone (E1) was examined in liver and kidney microsomes of adult castrated male and ovariectomized female hamsters and rats and in neonatal and immature hamster renal microsomes. In castrated male hamster liver microsomes, E1 was metabolized extensively to six major metabolites; 15 beta-hydroxyestrone, 7 alpha-hydroxyestrone, 6 alpha-hydroxyestrone, 6 beta-hydroxyestrone, 2-hydroxyestrone, and delta(9,11)-dehydroestrone, and a nonpolar fraction. Six minor metabolites of E1 were also detected. In contrast, kidney microsomes derived from castrated male hamsters metabolized E1 to mainly 17 beta-estradiol, 2- and 4-hydroxyestrone, 6 alpha-hydroxyestrone, 6 beta-hydroxyestrone and one monohydroxyestradiol metabolite. However, 16 alpha-hydroxyestrone was not detected. A variable, but low amount of estriol was also found. Interestingly, the quantity of 2-hydroxyestrone found in kidney microsomes of the hamster represented 26% of the total amount of metabolites formed, whereas in liver microsomes, only 9% of the overall metabolism resulted in the formation of 2-hydroxyestrone. The ability of kidney microsomes of female ovariectomized hamsters and two different rat strains to metabolize E1 was 5.9- and 9.4-fold lower, respectively, compared to renal microsomes of male castrated hamsters. The onset of oxidative metabolism in newborn hamster kidneys during development was also assessed. The results indicate that the oxidative metabolism of [14C]E1 in renal microsomes of newborn hamsters was 20-fold less than in kidney microsomes of adult hamsters. While catechol E1 metabolites were essentially negligible in hamster kidneys of these ages, it was evident that the conversion of E1 to estradiol via 17 beta-hydroxysteroid dehydrogenase resembles levels seen in the adult animals. Between the age of one and two months, the male hamster kidney exhibited the capacity to metabolize E1 at levels seen in fully mature adult hamsters.     

湖北宜昌震旦系-寒武系界线地层Micrhystridium regulare化石的发现及其地层意义

该文记述了国际前寒武系-寒武系界线层型候选剖面所在地,湖北宜昌震旦系-寒武系界线地层中发现的小刺球藻类化石Micrhystridium regulare,regulare,讨论了它们的产出层位及其归属,并对小刺球藻类化石在时间上、空间上的分布作了简要的归纳,最后提出了小刺球藻类化石在震旦系-寒武系界线地层的划分和大区域地层对比中重要的潜在作用。     

羊蹄甲属植物种子的裂解色谱鉴定法研究

本文探索了裂解气相色谱法作为植物种子分类表征方法的可能性。对豆科植物中不同属、不同亚属及相同亚属的共10种种子的裂解色谱图,用分区编码法进行区别,分析结果表明,不同种子最少有一个编码不同,方法简易快速,可为高等植物种子的区分提供一种佐证手段。     

雄性生殖单位研究的回顾和展望

本文扼要回顾和评述了雄性生殖单位的发现、意义和研究进展,并对目前存在的问题和今后的研究进行了讨论和展望。     

氧化塘中细菌种群组成动态

对武汉地区氧化塘中的细菌数量、细菌种类、种群组成、优势种及群落多样性进行了初步研究。从氧化塘中分离的细菌经鉴定属于12个属,主要有假单胞菌属(Pseudomonas)、棒杆菌属(corynebacterium)、无色杆菌属(Achromobacter)和微杆菌属(Microbacterium),其它菌属是芽孢杆菌属(Bacillus)、色杆菌属(Chromobacterium)、短杆菌属(Brevibacterium)、葡萄球菌属(Staphylococcus)、微球菌属(Micrococcus)、黄杆菌属(Flavobacterium)、埃希氏菌属(Escherichia)和链球菌属(Streptococcus)。在5个小塘中,细菌数量、种群组成和群落多样性指数都有不同,这与各塘的污染程度有关。由此,多样性指数可用于监测氧化塘的净化效果。     

若干种枝角类卵鞍表面亚显微结构的比较研究

以扫描电镜对发头裸腹溞、蚤状溞、隆线溞指名亚种以及隆线溞东湖一亚种的卵鞍分别进行了比较研究,发现卵鞍表面的亚显微结构有明显的差异,但亚种之间差异较小。隆线溞指名亚种与隆线溞东湖一亚种二者的卵鞍在光学显微镜下看不出有什么差异,然而亚显微结构却互不相同。这就为东湖一新亚种的确定提供了一项可靠的依据,同时也进一步证实卵鞍的超微结构确可作为枝角类分类的表征。     

湘中、湘东地区早籼稻耐土壤潜育性评价

我国南方稻区的主要低产稻田是潜育性稻田,约有一亿亩。挖掘其“潜在生产力”,种植耐潜育性土壤逆境胁迫能力较强的水稻品种,则是简便、经济而有效的重要途径之一。本文就几个早籼稻品种(组合)对潜育性稻田的生态适应性进行了较系统的观测,并初步提出了耐潜育性的几个鉴定指标,诸如根系生长量和幼穗分化期根系氧化力;分蘖早期茎蘖增长速率;分蘖后期单株干物质产量;乳熟期剑叶片过氧化氢酶活性GDI和光合强度等。上述鉴定指标,综合应用于水稻品种生态适应性和耐潜育性育种研究,有助于提高水稻抗逆性育种的效率。     

中国乌头属属下等级数量分类的初步研究

本文取中国乌头属50种(含变种)植物,选取形态学性状46个、化学性状8个、组织学性状5个、生态学性状1个,运用数量分类方法,对该属进行属下等级的分类研究。根据数学分析结果,确定了树系图中变种、种、系、亚属的分级界线,并在聚类分析的基础上,进一步探讨了各等级类群的划分。