15Alpha-hydroxyprogesterone in male sea lampreys, Petromyzon marinus L

There is growing evidence that sea lampreys, Petromyzon marinus L., produce gonadal steroids differing from those of other vertebrates by possessing an additional hydroxyl group at the C15 position. Here we demonstrate that sea lamprey testes produce 15alpha-hydroxyprogesterone (15alpha-P) in vitro when incubated with tritiated progesterone, that 15alpha-P is present in the plasma of sea lampreys, and that plasma concentrations of immunoreactive (ir) 15alpha-P rise dramatically in response to injections of gonadotropin-releasing hormone (GnRH). The identity of the tritiated 15alpha-P produced in vitro was confirmed by co-elution with standard 15alpha-P on high performance liquid chromatography, co-elution with standard and acetylated 15alpha-P on thin layer chromatography, and specific binding to antibodies raised against standard 15alpha-P. The in vitro conversion was used to produce tritiated 15alpha-P label for a radioimmunoassay (RIA), which is able to detect 15alpha-P in amounts as low as 2 pg per tube. The RIA has been used to measure the plasma concentrations of 15alpha-P in males given two serial injections, 24 h apart, of either lamprey GnRH I or GnRH III (50, 100, or 200 microg/kg) or saline control, with plasma being sampled 8 and 24 h after the second injection. Plasma concentrations of ir-15alpha-P rose from < 1 to 36 ng/ml (mean of all treatments) 8 h after injection and declined within 24 h. This is the first time that an RIA has detected such high steroid concentrations in lampreys. This finding is suggestive of a role for 15alpha-P in control of reproduction in the sea lamprey.     

Oceanimonas smirnovii sp. nov., a novel organism isolated from the Black Sea

A slightly creamy, melanogenic, gram-negative, aerobic bacterium was isolated from seawater sample collected in the Karadag Natural Reserve of the Eastern Crimea, the Black Sea. The novel organism was chemoorganotrophic, had no obligate requirement in NaCl, tolerated to 12% NaCl, grew between 10 and 45 degrees C, was slightly alkaliphilic, and was not able to degrade starch, gelatin, agar, and Tween 80. 16S rRNA gene sequence-based analyses of the new organism revealed that Oceanimonas doudoroffii ATCC 27123T, Oceanimonas baumanii ATCC 700832T, and Oceanisphaera litoralis DSM 15406T were the closest relatives (similarity around 97%-96%). The G + C content of the DNA of the strain 31-13T was 55.5mol%. Phosphatidylethanolamine (49.0%), phosphatidylglycerol (41.8%), and diphosphatidylglycerol (9.2%) were the predominant phospholipids. The major fatty acids were 16:0 (24.1%), 16:1omega7 (40.3%), and 18:1omega7 (29.2%). On the basis of the significant differences demonstrated in the phenotypic and chemotaxonomic characteristics, it is suggested that the bacterium be classified as a novel species; the name Oceanimonas smirnovii sp. nov. is proposed. The type strain is 31-13T (UCM B-11076T = LMG 22147T = ATCC BAA-899T).     

Diatoms of the genus Attheya west, 1860 from the Sea of Japan

This paper documents the species diversity of the diatom genus Attheya from the Sea of Japan. Two species (A. arenicola and A. longicornis) were studied in field samples and in culture. Their morphology is described using light and electron microscopy; the ecology and the distribution data are provided. A. arenicola is a new record for the seas of Russia.     

Tolerance of Pinus taeda and Pinus serotina to low salinity and flooding: Implications for equilibrium vegetation dynamics

Questions: 1. Do pine seedlings in estuarine environments display discrete or continuous ranges of physiological tolerance to flooding and salinity? 2. What is the tolerance of Pinus taeda and P. serotina to low salinity and varying hydrologic conditions? 3. Are the assumptions for ecological equilibrium met for modeling plant community migration in response to sea‐level rise? Location: Albemarle Peninsula, North Carolina, USA. Methods: In situ observations were made to quantify natural pine regeneration and grass cover along a salinity stress gradient (from marsh, dying or dead forest, to healthy forest). A full‐factorial greenhouse experiment was set up to investigate mortality and carbon allocation of Pinus taeda and P. serotina to low‐salinity conditions and two hydrology treatments over 6 months. Treatments consisted of freshwater and two salinity levels (4 ppt and 8 ppt) under either permanently flooded or periodically flushed hydrologic conditions. Results: Natural pine regeneration was common (5–12 seedlings per m²) in moderate to well‐drained soils where salinity concentrations were below ca. 3.5 ppt. Pine regeneration was generally absent in flooded soils, and cumulative mortality was 100% for 4 and 8 ppt salinity levels under flooded conditions in the greenhouse study. Under weekly flushing conditions, mortality was not significantly different between 0 and 4 ppt, confirming field observations. Biomass accumulation was higher for P. taeda, but for both pine species, the root to shoot ratio was suppressed under the 8 ppt drained treatment, reflecting increased below‐ground stress. Conclusions: While Pinus taeda and P. serotina are commonly found in estuarine ecosystems, these species display a range of physiological tolerance to low‐salinity conditions. Our results suggest that the rate of forest migration may lag relative to gradual sea‐level rise and concomitant alterations in hydrology and salinity. Current bioclimate or landscape simulation models assume discrete thresholds in the range of plant tolerance to stress, especially in coastal environments, and consequently, they may overestimate the rate, extent, and timing of plant community response to sea‐level rise.     

金门岛北部海域浮游植物的季节变动及与环境的关联

采用2013—2014年四季度月在金门岛北部海域获取的浮游植物及环境因子监测数据, 分析该区浮游植物的群落结构和季节变化及其与温度、盐度、悬浮物、营养盐、叶绿素等的关系, 初步探讨涉海工程建设对浮游植物群落的潜在影响。结果显示, 鉴定出的浮游植物隶属3门43属82种(不含未定种), 群落构成以硅藻为主, 其次是甲藻, 蓝藻仅1种。物种组成的季节差异较大, 3月物种贫乏, 1月次之, 7月和11月最丰富。四季丰度平均为47.09×103 cells/L, 1月丰度最高, 7月次之, 11月最低, 3月高于11月少许。四季优势种均为硅藻, 13个优势种分别为柔弱几内亚藻(Guinardia delicatula)、短角弯角藻(Ecampia zoodicaus)、骨条藻(Skeletonema spp.)、具槽帕拉藻(Paralia sulcata)、微小海链藻(Thalassiosira exigua)、标志星杆藻(Asterionella notula)、旋链角毛藻(Chaetoceros curvisetus)、新月菱形藻(Nitzchia closterium)、派格棍形藻(Bacillaria paxillifera)、异常角毛藻(Chaetoceros abmormis)、小细柱藻(Leptocylindrus minutum)、宽角曲舟藻(Pleurosigma angulatum)和美丽曲舟藻(Pleurosigma formosum)。不同季节优势种有一定程度交错, 仅在单季占优的有6种, 有2/3在3个以上季节出现, 具槽帕拉藻、骨条藻为四季优势种。浮游植物物种多样性和均匀度总体较好, 群落结构稳定。与毗邻海区相比, 本区物种丰富度偏低, 丰度高于毗邻海区, 种类组成相似, 优势种却有较大差别。Pearson相关分析表明, 溶解无机氮及活性磷酸盐仅在1月与丰度存在极显著的正相关, 是促使丰度为四季最高的原因。涉海工程施工产生的悬浮物和冲击波是影响浮游植物群落的主要因素, 大量海洋工程建设案例表明, 施工期造成的浮游植物丰度下降趋势和优势种更替混乱在工程结束后能得以恢复。     

Inhibition of replicative DNA synthesis in nuclei of Strongylocentrotus intermedium urchin embryo by 2′,3′-dideoxy-3′-aminonucleoside 5′-triphosphates

2′,3′-Dideoxy-3′-aminonucleoside 5′-triphosphates have been shown to be inhibitors of replicative DNA synthesis in isolated nuclei of sea urchin embryo. These compounds inhibit the Okazaki fragment synthesis. The effect of 2′,3′-dideoxy-3′-aminothymidine 5′-triphosphate and arabinothymidine 5′-triphosphate is reversible when adding the corresponding substrate for DNA synthesis, 2′-deoxythymidine 5′-triphosphate.     

菲律宾海北部底质沉积中的深海介形类

对琉球群岛东侧的菲律宾海北部海区(27.0°-30.0°N,129.5°-135.5°E)水深1 666 m至6 616 m的123个表层沉积物样品进行了定量微体古生物学研究.仅在38个样品中发现介形类,主要分布在4 000 m以浅水深区.初步鉴定有21属35种,其中Krithe在样品中的出现率和丰度最高,其次常见的还...     

Autotomy reduces feeding, energy storage and growth of the sea star Stichaster striatus

We evaluated the effect of autotomy on feeding, energy storage and growth of juvenile Stichaster striatus kept in the laboratory for five months with a limited supply of the mussel Semimytilus algosus. Autotomy strongly decreased feeding, energy storage and growth. Intact juveniles showed a ∼ 3 fold higher feeding rate than autotomized individuals throughout the experiment. Intact juveniles also had a higher (∼ 5 fold) energy content per pyloric caeca in each arm. This was mainly due to higher lipid content, the main proximate constituent of pyloric caeca. Intact juveniles showed a greater growth rate and reached a greater size than autotomized individuals, more evident for underwater mass than radius length. The reduced capacity to feed reduced energy intake in autotomized individuals. However, low energy reserves along with low growth in autotomized sea stars, support the hypothesis that juveniles of this species allocate energy to regeneration to the detriment of growth. This was also supported by the ∼ 25% of arm length regeneration after 5 mo. Remaining small could increase risk of lethal predation, however, S. striatus may reduce predation risk by using crevices and kelp holdfasts as refuges from predators. Given the strong impact of autotomy on feeding, regeneration of arms to recover full capacity to forage and grow seems a better strategy for juvenile S. striatus, than merely growing.     

2007年10月南海北部浮游纤毛虫的丰度和生物量

报道2007年10月南海北部海域(21°25.47′N 17°24.95′N,109°28.86′E 113°13.01′E)纤毛虫丰度和生物量的水平分布及砂壳纤毛虫的种丰富度。包括了13个断面的82个站位,Rosette采水器采水,水深低于15 m的站位采0,5 m和10 m;小于30 m站位,采0,10 m和底层;大于30 m的站位,采0,10,30 m和底层。纤毛虫丰度为0 5757 ind./L,平均(848±776)ind./L。无壳纤毛虫占绝对优势,其丰度占纤毛虫总丰度的比例平均为(91.9±9)%;纤毛虫生物量为0 12.09μg C/L,平均是(1.2±1.54)μg C/L,无壳纤毛虫的生物量平均为(0.94±1.27)μg C/L,占纤毛虫总生物量的78.6%。共发现砂壳纤毛虫16个属,49种,拟铃虫最多,具有一定的季节性。纤毛虫水体(40 m到表层)丰度为6.4×1069.1×107ind./m2,平均是(3.6×106±1.4×106)ind./m2;水体生物量3.6 195.8 mg C/m2,平均(48.1±33.7)mg C/m2。纤毛虫多分布于近岸浅水区(高温低盐,高Chl a),最大丰度要高于我国其他海区,不是Chl a最高的地方纤毛虫的丰度也最大,纤毛虫丰度最大时Chl a偏低。     

The dieback ofZostera marina in the 1930's in the Waddensea; An eye-witness account by A. van der Werff

In the archives of the State Institute of Fisheries Research a handwritten report of A. van der Werff on the wasting disease ofZostera marina L. in the Waddensea in 1932 and 1933 is kept. It contains an eye-witness account of the decline of the eelgrass beds. In 1932 the first attack of the disease took place in May and caused heavy devastation. Regeneration started soon, but a second attack at the end of August seemed to destroy the beds definitively. The next year was a year of struggle for the few poorly developed surviving plants. In 1938 the last surviving specimens were seen in the sublittoral.