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排序方式: 共有153条查询结果,搜索用时 62 毫秒
1.
Lucas C. Maltez Luis A. L. Barbas Marcelo H. Okamoto Diogo L. de Alcantara Lopes Luis A. Romano Luís A. Sampaio Luciano Garcia 《Journal of the World Aquaculture Society》2019,50(2):346-358
This study investigated the secondary stress responses of Paralichthys orbignyanus exposed to ammonia and nitrite and after recovery. Fish were exposed to 0.12, 0.28, and 0.57 mg NH3‐N/L, or 5.72, 10.43, and 15.27 mg NO2‐N/L for 10 d followed by the same time length for recovery. Ammonia‐ and nitrite‐free water was used as a control treatment. Blood samples were collected after 1, 5, and 10 d of exposure and after recovery. Fish exposed to ammonia presented lower and higher glucose levels after 10 d of exposure and recovery, respectively. Ammonia induced initial and transient ionic disturbances and metabolic alkalosis. Nitrite exposure caused hyperglycemia, increased plasma K+ levels, and respiratory alkalosis, whereas metabolic acidosis was observed after recovery. Increased proportion of monocytes and/or granulocytes and reduced number of lymphocytes were demonstrated in fish exposed to 0.28 mg NH3‐N/L (Day 1) and 10.43 mg NO2‐N/L (Day 5) and after recovery in the 0.28 and 0.57 mg NH3‐N/L treatments. Exposure to ammonia decreased the proportion of granulocytes on Day 5. In conclusion, exposure to concentrations at 0.12 mg NH3‐N/L and 5.72 mg NO2‐N/L provoked physiological disorders in Brazilian flounder. Nonetheless, fish exposed to 5.72 mg NO2‐N/L following a 10‐d recovery period showed complete resumption of homeostasis. 相似文献
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3.
Wen-Ying Wang Wei-Wei Chai Chang-Yu Zhao Owen Rowland Bao-Shan Wang Xin Song Ya-Qi Liu Qing Ma Suo-Min Wang 《植物养料与土壤学杂志》2019,182(4):597-606
Zygophyllum xanthoxylum is a salt‐accumulating xerophytic species with excellent adaptability to adverse environments. Previous studies demonstrated that Z. xanthoxylum absorbs a great quantity of Na+ as an osmoregulatory substance under arid conditions. To investigate the nutritional status of Z. xanthoxylum in comparison with a typical glycophyte, Arabidopsis thaliana, seedlings were exposed to NaCl (50 mM for Z. xanthoxylum and 5 mM for A. thaliana), osmotic stress (–0.5 MPa), and osmotic stress combined with the NaCl treatment. Compared to the control, NaCl treatment or osmotic stress significantly increased Na+ concentration in leaves and roots of Z. xanthoxylum, but not of A. thaliana. Under osmotic stress, the addition of NaCl significantly increased Na+ concentration in leaves and roots of Z. xanthoxylum, resulting in improved biomass and tissue water content. However, such changes were not observed in A. thaliana. Compared to the control, K+ concentrations in leaves and roots remained unchanged in Z. xanthoxylum when exposed to osmotic stress, with or without additional 50 mM NaCl. In contrast, significant reductions in shoot K+ concentrations of A. thaliana were observed under osmotic stress alone or when combined with 5 mM NaCl. Moreover, NaCl alone or when combined with osmotic stress enhanced the accumulation of N, P, Fe, Si, Ca2+, and Mg2+ in Z. xanthoxylum, but did not cause such nutritional changes in A. thaliana. Compared to the glycophyte A. thaliana, Z. xanthoxylum could accumulate Na+ and maintain the stability of nutritional status at a relatively constant level to cope with drought stress. 相似文献
4.
F.M. Trefz A. Lorch J. Zitzl A. Kutschke G. Knubben‐Schweizer I. Lorenz 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2015,29(2):688-695
Background
Neonatal diarrheic calves have a clear negative potassium balance because of intestinal losses and decreased milk intake but in the presence of acidemia, they usually show normokalemic or hyperkalemic plasma concentrations.Objectives
To assess whether marked hypokalemia occurs in response to the correction of acidemia and dehydration and to identify factors that are associated with this condition.Animals
Eighty‐three calves with a clinical diagnosis of neonatal diarrhea.Methods
Prospective cohort study. Calves were treated according to a clinical protocol using an oral electrolyte solution and commercially available packages of 8.4% sodium bicarbonate, 0.9% saline and 40% dextrose infusion solutions.Results
The proportion of hypokalemic calves after 24 hours of treatment (19.3%) was twice as great as it was on admission to the hospital. Plasma K+ after 24 hours of treatment was not significantly correlated to venous blood pH values at the same time but positively correlated to venous blood pH values on admission (r = 0.51, P < .001). Base excess on admission (Odds ratio [OR] = 0.81, 95% confidence interval [CI] = 0.70–0.94), duration of diarrhea (OR = 1.37, 95% CI = 1.05–1.80), milk intake during hospitalization (OR = 0.54, 95% CI = 0.37–0.79) and plasma sodium concentrations after 24 hours (OR = 1.12, 95% CI = 1.01–1.25) were identified to be independently associated (P < .05) with a hypokalemic state after 24 hours of treatment.Conclusions and Clinical Importance
Findings of this study suggest that marked depletion of body potassium stores is evident in diarrheic calves that suffered from marked metabolic acidosis, have a low milk intake and a long history of diarrhea. 相似文献5.
Omid Askari-Khorasgani 《Journal of plant nutrition》2019,42(10):1268-1275
Drought stress is considered one of the major constraints to crop production with devastating effects worldwide. Methylglyoxal (MG) homeostasis plays an essential role in promoting plant growth, development, metabolic adaptation, signal transduction, and thereby responses to drought stress. Manipulation of genes encoding aldose-aldehyde reductases (ALRs), aldo– keto reductases (AKRs), genes that are involved in maintaining high ascorbate:glutathione (AsA:GSH), glutathione:glutathione disulfide (GSH:GSSG) contents and ratios, as well as jasmonic acid (JA) biosynthesis are of critical importance for improving MG detoxification, and thereby tolerance to drought stress. MG detoxification by maintaining optimal abscisic acid (ABA), JA, salicyclic acid (SA), and brassinosteroid (BR) homeostasis and crosstalk is also essential to optimize plant performance under both normal and drought stress conditions. 相似文献
6.
Salinity is a common issue of semi-arid and arid lands rendering them unfit for agriculture. Saline wastelands can be converted into productive ecosystems by rehabilitating them with salt tolerant native tree species. The objective of this work was to study the effect of NaCl salinity on tissue nutrient contents of the four dryland tree species. Saplings were grown in pots under nonsaline and high salinity conditions. After eighteen weeks the plants were harvested and their tissue nutrient contents were analyzed. Results revealed that all species accumulated high amounts of Na+ under saline conditions, while concentrations of N, P and Mg2+ decreased in their tissues. Concentrations of K+ and Ca2+ showed more variable trend in various tissues in response to increase in soil salinity. Na+: K+ ratios of roots (1.57), stems (1.27), and leaves (1.66) of salinized Salvadora oleoides plants were lowest among all the four species. Root Na+: K+ ratio of salinized plants was significantly higher for Prosopis cineraria (7.10), while these ratios for stem (1.85) and leaf (3.42) were highest for Tamarix aphylla. Plants of P. cineraria showed lowest Stem-Na+/root-Na+ ratio (0.30) when subjected to salinity. Results showed that salinity induces nutrient deficiency in all species. Salinity tolerance of these species can be attributed to their ability to (i) restrict translocation of Na+ from roots to stem; (ii) keeping low tissue Na+: K+ ratios; and (iii) selectivity of K+ and Ca2+ over Na+, and can be used for the screening of salt-tolerant ecotypes for the rehabilitation of saline wastelands. 相似文献
7.
为探讨钙稳态失衡在LsCl3诱导MDCC-MSB1细胞凋亡中的作用,MDCC-MSB1细胞常规培养于RPMI1640培养液中,加入终浓度为0.5,1,1.5,2,2.5,3,3.5和4 mmol·L-1的LaCl3,继续培养24 h后,应用MTT法检测细胞增殖抑制率,DNA Ladder法和TUNEL法检测细胞凋亡,以Fura-2为荧光探针检测细胞内[Ca2+]i的变化.结果表明,在LaCl3浓度为0.5~4 mmol·L-1时,细胞的增殖抑制率增加,细胞凋亡数量和细胞内[Ca2+]i呈升高趋势,并呈剂量-效应关系.这表明LaCl3能抑制MDCC-MSB1细胞的增殖,并可能通过改变[Ca2+]i而诱导其发生凋亡. 相似文献
8.
为探究琥珀酸黄杆菌(Flavobacterium succinicans)对非生物胁迫下多年生黑麦草(Lolium perenne)的缓解效应,本试验研究了菌株DSM4002的生物学特性,并在盆栽条件下,分析了干旱(维持相对含水量(30±5)%处理7 d和14 d)、低温(4℃处理3 d和7 d)和盐胁迫(150 mM NaCl处理5 d和10 d)下根际接种DSM4002对多年生黑麦草生长和生理特性的影响。结果表明,DSM4002具有分泌吲哚乙酸(Indole-3-acetic acid,IAA)、溶磷和产铁载体能力,对壮观霉素、卡那霉素等具有抗性,对氯霉素敏感。同时,接种DSM4002能够提高正常生长、干旱、低温和盐胁迫下多年生黑麦草的生物量、抗氧化酶活性、可溶性糖和脯氨酸含量,降低相对电导率和丙二醛(Malondialdehyde,MDA)含量。综上,琥珀酸黄杆菌促进多年生黑麦草的生长与其自身具有分泌IAA、溶磷和产铁载体能力有关,而且它能够调节植物体内氧化还原平衡,从而增强多年生黑麦草的抗旱、抗寒和抗盐能力。 相似文献
9.
Jiali Zhang Wenshui Xia Ping Liu Qinyuan Cheng Talba Tahirou Wenxiu Gu Bo Li 《Marine drugs》2010,8(7):1962-1987
Chitosan has received much attention as a functional biopolymer for diverse applications, especially in pharmaceutics and medicine. Our recent efforts focused on the chemical and biological modification of chitosan in order to increase its solubility in aqueous solutions and absorbability in the in vivo system, thus for a better use of chitosan. This review summarizes chitosan modification and its pharmaceutical/biomedical applications based on our achievements as well as the domestic and overseas developments: (1) enzymatic preparation of low molecular weight chitosans/chitooligosaccharides with their hypocholesterolemic and immuno-modulating effects; (2) the effects of chitin, chitosan and their derivatives on blood hemostasis; and (3) synthesis of a non-toxic ion ligand—D-Glucosaminic acid from Oxidation of D-Glucosamine for cancer and diabetes therapy. 相似文献
10.
A greenhouse experiment was carried out to examine the differential morpho‐physiological responses of five cultivars of turnip (Brassica rapa L.) to salt stress. Five diverse cultivars of turnip (shaljum desi surakh, shaljum purple top, shaljum golden bal, neela shaljum, and peela shaljum) were subjected for 6 weeks to varying levels of NaCl, i.e. 0, 80 and 160 mm in Hoagland’s nutrient solution in sand culture. Imposition of varying levels of salt substantially decreased shoot and root fresh and dry weights, chlorophyll contents, leaf osmotic potential, relative water contents, different gas exchange attributes, total phenolics, malondialdehyde, activities of superoxide dismutase, peroxidase catalase, and leaf and root K+ levels while enhanced the proline contents, membrane permeability, level of H2O2, leaf and root Na+ and Cl? and leaf Ca2+ in all turnip cultivars under study. Of all cultivars, peela shaljum and neela shaljum were consistently higher in their growth than the other turnip cultivars at all salt concentrations of the growth medium. Photosynthetic capacity (A) and stomatal conductance (gs) were higher in high biomass‐producing cultivars, i.e. peela shaljum and neela shaljum, which provide to be potential selection criteria of salt tolerance in turnip. However, the regulation of antioxidant system was cultivar‐specific under saline conditions. 相似文献