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81.
Planktonic, epipelic and epiphytic algae were studied monthly, during the period from January to December 1985 in the Garmat ali river, a naturally regulated river draining to the al-Hammar marsh, Iraq. Chlorophyll-a, primary productivity and water quality variables were also measured. High light penetration was noticed during the winter and spring. The water is oligohaline, alkaline and very hard. Reactive nitrate was found in higher concentrations than nitrite, and there were low concentrations of reactive phosphate. Two peaks were noticed for chlorophyll-a concentrations during spring and autumn, whereas only one occurred during autumn for primary productivity. The study area may be characterized as typically mesotrophic. A total of 154 species of algae was identified, including 65, 89, 98 and 77 species of plankton, epipelic and epiphytic algae on Potamogeton lucens and on Ceratophyllum demersum, respectively. Only 25 species were common to all the different communities. Diatoms were the dominant group in the epipelic and epiphytic algae during the study period, as well as in the plankton during spring and autumn. Seasonal variations were clear in the total cell numbers of algae from different habitats. 相似文献
82.
分析了塔河、普光两个海相大型油气田的地质特征和发现过程,展现了我国海相油气勘探的巨大发展前景。指出在今后一个较长时期内,海相油气勘探将是中国石化寻技大中型油气田、实现油气资源接替的主要领域。 相似文献
83.
Paraskevi Malea Danae Kokkinidi Alkistis Kevrekidou Ioannis-Dimosthenis S. Adamakis 《International journal of molecular sciences》2022,23(3)
The effects of environmentally relevant bisphenol A (BPA) concentrations (0.3, 1 and 3 μg L−1) were tested at 2, 4, 6 and 8 days, on intermediate leaves, of the seagrass Cymodocea nodosa. Hydrogen peroxide (H2O2) production, lipid peroxidation, protein, phenolic content and antioxidant enzyme activities were investigated. Increased H2O2 formation was detected even at the lowest BPA treatments from the beginning of the experiment and both the enzymatic and non-enzymatic antioxidant defense mechanisms were activated upon application of BPA. Elevated H2O2 levels that were detected as a response to increasing BPA concentrations and incubation time, led to the decrease of protein content on the 4th day even at the two lower BPA concentrations, and to the increase of the lipid peroxidation at the highest concentration. However, on the 6th day of BPA exposure, protein content did not differ from the control, indicating the ability of both the enzymatic and non-enzymatic mechanisms (such as superoxide dismutase (SOD) and phenolics) to counteract the BPA-derived oxidative stress. The early response of the protein content determined that the Low Effect Concentration (LOEC) of BPA is 0.3 μg L−1 and that the protein content meets the requirements to be considered as a possible early warning “biomarker” for C. nodosa against BPA toxicity. 相似文献
84.
85.
论述了在国外品牌船用增压器的基础上,通过对产品尺寸等的优化,开发出国产露笑品牌船用增压器,该增压器具有工作点效率高而喘振裕度又大的特点,和主机厂的配机及使用情况表明:性能较好,达到设计目的。 相似文献
86.
某型艇的风冷柴油发电机组在试验时发现调速性能超差、达不到要求的精度。通过对风冷柴油机结构特点的分析论证,选用国产成熟的电子调速器进行匹配。试验验证表明,达到了机组成套技术要求的精度等级。 相似文献
87.
Anna Kloska Grzegorz M. Cech Dariusz Nowicki Monika Macig-Dorszyska Aleksandra E. Bogucka Stephanie Markert Drte Becher Katarzyna Potrykus Paulina Czaplewska Agnieszka Szalewska-Paasz 《International journal of molecular sciences》2022,23(2)
Osmotic changes are common challenges for marine microorganisms. Bacteria have developed numerous ways of dealing with this stress, including reprogramming of global cellular processes. However, specific molecular adaptation mechanisms to osmotic stress have mainly been investigated in terrestrial model bacteria. In this work, we aimed to elucidate the basis of adjustment to prolonged salinity challenges at the proteome level in marine bacteria. The objects of our studies were three representatives of bacteria inhabiting various marine environments, Shewanella baltica, Vibrio harveyi and Aliivibrio fischeri. The proteomic studies were performed with bacteria cultivated in increased and decreased salinity, followed by proteolytic digestion of samples which were then subjected to liquid chromatography with tandem mass spectrometry analysis. We show that bacteria adjust at all levels of their biological processes, from DNA topology through gene expression regulation and proteasome assembly, to transport and cellular metabolism. The finding that many similar adaptation strategies were observed for both low- and high-salinity conditions is particularly striking. The results show that adaptation to salinity challenge involves the accumulation of DNA-binding proteins and increased polyamine uptake. We hypothesize that their function is to coat and protect the nucleoid to counteract adverse changes in DNA topology due to ionic shifts. 相似文献
88.
Qing-Chao Li Bo Wang Yan-Hua Zeng Zhong-Hua Cai Jin Zhou 《International journal of molecular sciences》2022,23(7)
Marine biofouling is a worldwide problem in coastal areas and affects the maritime industry primarily by attachment of fouling organisms to solid immersed surfaces. Biofilm formation by microbes is the main cause of biofouling. Currently, application of antibacterial materials is an important strategy for preventing bacterial colonization and biofilm formation. A natural three-dimensional carbon skeleton material, TRP (treated rape pollen), attracted our attention owing to its visible-light-driven photocatalytic disinfection property. Based on this, we hypothesized that TRP, which is eco-friendly, would show antifouling performance and could be used for marine antifouling. We then assessed its physiochemical characteristics, oxidant potential, and antifouling ability. The results showed that TRP had excellent photosensitivity and oxidant ability, as well as strong anti-bacterial colonization capability under light-driven conditions. Confocal laser scanning microscopy showed that TRP could disperse pre-established biofilms on stainless steel surfaces in natural seawater. The biodiversity and taxonomic composition of biofilms were significantly altered by TRP (p < 0.05). Moreover, metagenomics analysis showed that functional classes involved in the antioxidant system, environmental stress, glucose–lipid metabolism, and membrane-associated functions were changed after TRP exposure. Co-occurrence model analysis further revealed that TRP markedly increased the complexity of the biofilm microbial network under light irradiation. Taken together, these results demonstrate that TRP with light irradiation can inhibit bacterial colonization and prevent initial biofilm formation. Thus, TRP is a potential nature-based green material for marine antifouling. 相似文献
89.
90.
海洋贝类多糖的制备及生物活性研究概况 总被引:2,自引:0,他引:2
综述了海洋贝类多糖的多种制备技术(酶法、柱层析法、膜分离法等)及其增强免疫力、抗肿瘤、抗病毒等多种生物活性的研究进展,证明海洋贝类多糖是一种极具开发潜力和价值的天然功能食品,作为抗肿瘤、抗病毒药物有着广阔的应用前景。 相似文献