硒对紫球藻抗氧化酶活性及丙二醛含量的影响

利用添加0.5mg.L-1硒的人工海水(ASW)培养基培养紫球藻Porphyridium sp.UTEX 637,并采用试剂盒、氯化硝基四氮唑蓝(NBT)光化学还原反应法、紫外分光光度法、硫代巴比妥酸(TBA)分析法测定谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)的活性及丙二醛(MDA)的含量,着重探讨硒对紫球藻抗氧化酶活性及丙二醛含量的影响。结果表明,硒明显促进紫球藻细胞的GSH-Px活性(p<0.05)。加硒处理组和未加硒对照组紫球藻的GSH-Px活性均在第15天达到最高;加硒组紫球藻的最大酶活性达到4.31个酶活力单位(U),为对照组的1.31倍。SOD和CAT的活性分别在第18天和15天达到最大值,但加硒组与对照组之间差异不显著(p>0.05),说明0.5mg.L-1硒对紫球藻的SOD和CAT活性影响不明显。加硒能明显降低藻细胞丙二醛的含量,加硒组藻细胞的丙二醛含量比对照组藻细胞的丙二醛含量降低了15.21%。     

Untersuchung von drei Grundwasserwerken auf Vorkommen von Acanthamoeben,Naeglerien und anderen freilebenden Amöben

Prevalence of Acanthamoebae, Naegleriae and Other Free-living Amoebae in the Course of Water Treatment in Three Well Waterworks Numerous species of free-living amoebae and other protozoa had been observed in the raw water of three representative waterworks with enriched well water. They were eliminated most effectively during the water treatment procedure. Acanthamoebae and Naegleriae including thermophilic strains of these genera could not be identified in any of the clear water samples. Acanthamoebae and Vannellae isolated from different samples exhibited repeatedly intracellular infections with bacteria of the genus Cytophaga. Their role as possible hosts of different pathogenic and non pathogenic bacteria like Legionella sp., Listeria sp., and Pseudomonas sp. is confirmed by this observation. As known from earlier findings in connection with the Acanthamoeba-Legionella model, it can be assumed, that bacteria multiplying in trophozoites or being enclosed in cysts are protected against high concentrations of chlorine and other biocides.     

藏北班戈、申扎地区志留纪和泥盆纪珊瑚及其意义

本文描述了藏北志留纪和泥盆纪皱纹珊瑚6属,7种,其中3个新种;床板珊瑚5属,7种,其中有4个新种;日射珊瑚1属1种,并讨论了本区志留纪和泥盆纪地层的发育特征和沉积类型。     

Prevention and Control of Continuous Cropping Obstacle of Watermelon by Reductive Soil Disinfestation (RSD)

This study aimed to explore whether reductive soil disinfestation (RSD) is an effective method of controlling continuous cropping obstacle of watermelon. Samples of watermelon continuous cropping soils were treated by RSD in laboratory tests and pot experiments in August 2015 and from December 10, 2016 to April 10, 2017. The soil samples for the laboratory test were divided into 16 groups, and each group comprised three parallel samples of 100 g (dry soil weight). Except for the original and control (CK) samples, the 14 other groups of soil samples were treated with different combinations of 1% or 3% alfalfa powder, 1% or 3% ammonia (NH₃) water, and 1% or 3% acetic acid. The soil samples were placed inside size-five self-styled plastic bags and incubated in a constant-temperature biochemical incubator at 35°C for 14 days after blending, flooding, and sealing. Seven groups of soil samples were designed for the pot experiments based on the laboratory test results. Each group consisted of 30 parallel samples of 3 kg (dry soil weight). These samples were incubated outdoors for 4 months after mixing with alfalfa powder and/or NH₃ and/or acetic acid according to the experimental design, blending, flooding, and sealing. Watermelon seedlings were planted in the air-dried soil samples from May to July in 2017. The results showed that the pH of the soil samples treated by RSD were elevated except for those samples with acetic acid. In addition, the electrical conductivities of the soil samples treated by RSD were effectively adjusted. The presence of soil-borne pathogenic Fusarium oxysporum f.sp. niveum was significantly suppressed (p < 0.05) in soil samples treated by RSD, and the incidence and mortality rate of watermelons planted in these samples were remarkably lower than those planted in the CK and flooded CK soil samples. Therefore, continuous cropping obstacle of watermelon can be controlled by RSD.     

Colonization and Probiotic Effect of Metschnikowia sp. C14 in the Intestine of Juvenile Sea Cucumber,Apostichopus japonicus

Viable cell count was used to determine whether Metschnikowia sp.C14 can colonize the intestine of juvenile sea cucumber Apostichopus japonicus.Sea cucumber individuals were divided into two groups,which were fed the control diet for 38 days or the C14-supplemented diet at 105 cells g−1 diet for 28 days,then the control diet from day 29 to day 38.The number of C14 cells in the intestine of sea cucumber fed the C14-supplemented diet significantly increased from day 7 to day 28,and decreased from day 29 to day 38.Sea cucumber fed with the diet containing C14 showed a significant increase in trypsin activity and lipase activity from day 21 to day 33 compared with the control.Feeding C14 significantly improved the phagocytic activity and respiratory burst in coelomocytes from day 21 to day 35 and from day 14 to day 38,respectively.In addition,there was an obvious enhancement in lysozyme activity(from day 21 to day 38 or day 33),phenoloxidase activity(from day 21 to day 28)and total nitric oxide synthase activity(from day 14 to day 38)in coelomic fluid supernatant and/or coelomocyte cell lysate supernatant compared with the control.There were significant positive correlations between the number of C14 cells colonizing the intestine and trypsin activity of the intestine,lysozyme activity of the coelomic fluid supernatant and coelomocyte lysate supernatant from sea cucumber.These data suggested that the number of C14 cells should be maintained at 105 cfu(colony-forming units)g−1 intestine material for the maximum benefit.     

新发现的江河寄生性等足类——细角鳃虫的人工感染试验

珠江水系贺江段近年出现严重危害网箱养殖和江河鱼类资源的大型寄生虫病害,初步鉴定该虫隶属于甲壳纲,等足目,鳃虫科,细角鳃虫属,是国内新发现的淡水鱼类寄生虫。用该虫对草鱼、银鲫、麦鲮进行人工感染,结果表明:该虫具有很强的寄生能力,累积感染率为76.2%~100.0%;对寄生部位具有一定的选择性,以寄生在鳃部的比例(55.6%~72.0%)最大,胸鳍(11.7%~28.8%)次之;对试验鱼有较强的致死性;该虫吸血后体长(L)增长较大,体宽(W)基本不变;从寄主体上主动脱落的虫体,其L/W的增长率(16.32%~18.00%)较大,而一直寄生在寄主身上的虫体,其L/W的增长率则因各自摄食量的不同而存在较大的差异。     

Bioflocculant Produced by Klebsiella sp. MYC and Its Application in the li＇eatment of Oil-field Produced Water

Seventy-nine strains of bioflocculant-producing bacteria were isolated from 3 activated sludge samples. Among them, strain MYC was found to have the highest and stable flocculating rate for both kaolin clay suspension and oil-field produced water. The bacterial strain was identified as Klebsiella sp. MYC according to its morphological and biochemical characteristics and 16SrDNA sequence. The optimal medium for bioflocculant production by this bacterial strain was composed of cane sugar 20 g L^-1, KH2PO4 2 g L^-1, K2HPO4 5 g L^- 1, （ NH4）2SO4 0.2 g L^-1, urea 0.5 g L^- 1 and yeast extract 0.5 g L^- 1, the initial pH being 5.5. When the suspension of kaolin clay was treated with0.5% of Klebsiella sp. MYC culture broth, the flocculating rate reached more than 90.0% in the presence of 500mg L^-1 CaCI2, while the flocculating rate for oil-field produced water was near 80.0% in a pH range of 7.0 - 9.0 with the separation of oil and suspended particles from the oil-field produced water under similar conditions. The environment-friendly nature of the bioflocculant and high flocculating rate of the strain make the bioflocculant produced by Klebsiella sp. MYC an attractive bioflocculant in oil-field produced water treatment.     

Enhanced carotenoid production by a mutant of the marine yeast Rhodotorula sp. hidai

After a serial of UV, EMS and NTG mutagenesis, a mutant named MM of the red marine yeast strain Rhodotorula sp. hidai was obtained. The mutant MM could produce 603.93 μg g⁻¹ of carotenoid within 5 days in the medium containing 4.0 g sucrose, 1.5 g yeast extract, 0.1 g MgSO₄, and 100 mL of sea water, with pH 6.0 and at 30 °C, while only 213.18 μg g⁻¹ of carotenoid was produced by the wild type under the same conditions.     

Long‐term demographic and reproductive trends in Ciona intestinalis sp. A

Ciona intestinalis sp. A (Tunicata, Ascidiacea) is a marine invertebrate with a widespread distribution and high invasive potential, yet little is known about its ecology. Here, the macrodynamics of demographic and reproductive trends were first determined using archive data covering 2002–2012. Species abundance in the central Tyrrhenian Sea (Campania, Italy ‐ NW Mediterranean) displayed Poisson distribution across 2002–2008, massive die‐off in 2009/2010 and population recovery in 2011/2012. We defined the seasonal ranges of sea surface temperature in which sampling size, animal size and reproductive status reached their highest values. In 2003/2004, self and non‐self fertilization appeared to follow reverse trends across the year. The long‐term recording run here on Ciona intestinalis sp. A provides novel insights into its population biology and ecology, and represents a valuable tool for sampling management and research planning.