Cadmium-Containing Carbonic Anhydrase CDCA1 in Marine Diatom Thalassiosira weissflogii

The Carbon Concentration Mechanism (CCM) allows phytoplakton species to accumulate the dissolved inorganic carbon (DIC) necessary for an efficient photosynthesis even under carbon dioxide limitation. In this mechanism of primary importance for diatoms, a key role is played by carbonic anhydrase (CA) enzymes which catalyze the reversible hydration of CO₂, thus taking part in the acquisition of inorganic carbon for photosynthesis. A novel CA, named CDCA1, has been recently discovered in the marine diatom Thalassiosira weissflogii. CDCA1 is a cambialistic enzyme since it naturally uses Cd²⁺ as catalytic metal ion, but if necessary can spontaneously exchange Cd²⁺ to Zn²⁺. Here, the biochemical and structural features of CDCA1 enzyme will be presented together with its putative biotechnological applications for the detection of metal ions in seawaters.     

盐碱胁迫对尼罗罗非鱼鳃Na+/HCO3-共转运子、碳酸酐酶基因表达的影响

为了探讨盐碱胁迫条件下鱼类渗透生理调节机制,以尼罗罗非鱼(Oreochromis niloticus)为实验材料, PCR扩增得到了Na+/3HCO-共转运子(NBCe1)基因cDNA部分序列,比较了单盐(盐度10、盐度15)、单碱(1.5 g/L、3 g/L NaHCO3)、盐碱混合(盐度10,碱度1.5 g/L；盐度15,碱度3 g/L)胁迫后不同时间(0 h、6 h、12 h、24 h、48 h、72 h、96 h)血清渗透压、离子浓度(Na+、K+、Cl–、Ca2+)以及鳃碳酸酐酶(CA)活性、CA与NBCe1基因mRNA表达变化。结果显示,不同胁迫条件下,血清渗透压、离子浓度、鳃组织 CA 酶活、CA 与 NBCe1基因 mRNA 表达变化均与胁迫强度呈正相关。随时间推移,血清渗透压、离子浓度呈现先上升后下降的变化趋势,单盐、盐碱混合组血清渗透压值较单碱组高。单盐、单碱、盐碱混合组中, NBCe1基因mRNA在鳃中均呈略微上调,但不显著(P>0.05)。单碱组和盐碱混合组鳃CA活性较单盐组高,低盐碱胁迫(盐度10,碱度1.5 g/L)下CA活性较晚达最高值；不同胁迫条件下, CA基因mRNA表达均表现上调,单碱、盐碱混合组更为显著(P<0.05),推测CA较NBCe1对体内3HCO-转运作用更为显著。研究结果为尼罗罗非鱼盐碱适应生理调节提供了基础资料。     

盐分胁迫对油菜碳酸酐酶活性的影响

对盐胁迫下油菜光合作用、碳酸酐酶活性和叶绿素含量的变化进行了研究。结果表明,随着盐浓度的提高,碳酸酐酶活性下降,油菜的光合速率降低,叶绿素含量先增加后减少。这说明,盐胁迫抑制了碳酸酐酶的活性,不同程度地破坏了植物的光合机构,气孔关闭,碳酸酐酶对光合作用的调控作用使得碳酸酐酶活性降低的同时光合速率也下降;盐胁迫下植物叶片中叶绿素含量下降,其主要原因是由于NaCl能增强叶绿素酶活性,促进叶绿素分解。     

不同种类微生物及其碳酸酐酶对土壤-灰岩系统钙镁锌元素迁移作用的土柱模拟实验研究

通过土柱模拟实验研究了筛选自西南岩溶区的典型细菌、真菌、放线菌对石灰岩的溶蚀动态及作用效果,并研究了这3种类群微生物及其碳酸酐酶(CA)对土壤-灰岩系统Ca、Mg、Zn元素迁移的影响。结果表明:①实验所用的典型细菌、真菌、放线菌均对石灰岩有较强的溶蚀作用,但是不同类群的微生物对石灰岩的溶蚀效果不同,溶蚀后石灰岩的表面形貌变化不同,其中,真菌的溶蚀效果最显著,放线菌和细菌次之;②典型细菌、真菌、放线菌对不同元素迁移的影响不同,对于Zn2 、Ca2 的迁移影响而言,真菌>放线菌>细菌>无菌对照组;对于Mg2 的迁移影响而言,细菌>真菌>放线菌>无菌对照组;③一定范围内温度增加对Ca、Mg、Zn3种元素的迁移有不同程度的促进作用;④土柱淋出液中CA平均活性与Ca、Mg、Zn3种元素的总淋失量之间存在一定的正相关关系,说明CA对这3种元素的迁移具有一定的影响,且因不同元素而异。本研究结果对于评价不同类群微生物在生物岩溶及岩溶系统元素迁移中的作用和地位提供了一定的科学依据。     

Phosphorus ameliorates crop productivity,photosynthetic efficiency,nitrogen-fixation,activities of the enzymes and content of nutraceuticals of Lablab purpureus L.

Hyacinth bean (Lablab purpureus L.) serves as a good source of vegetable proteins in human diet. Its seeds and pods contain as much as 20–28% protein. Besides, it contains tyrosinase enzyme, which has potential use in the treatment of hypertension. Phosphorus deficiency causes a serious yield and quality constraint of beans at Aligarh, Western Uttar Pradesh, India. To address the problem, a pot experiment was conducted to study the effect of basal phosphorus application on the agricultural performance of this medicinal legume. The plants were grown in pots containing soil supplied with five levels of phosphorus viz. 0, 25, 50, 75 and 100 mg P kg⁻¹ soil as potassium dihydrogen orthophosphate (KH₂PO₄). The growth and other physiological attributes, leaf nutrient contents, nodule-nitrogen and leghemoglobin content were studied at 60, 90 and 120 days after sowing (DAS), photosynthesis and other related parameters were measured at 90 DAS and yield and quality attributes were recorded at harvest (150 DAS). Nitrate reductase and carbonic anhydrate activities, leaf-N, -P, -K and -Ca contents and nodule-nitrogen and leghemoglobin contents reached the maximum extent at 60 DAS. At 90 and 120 DAS, the values decreased significantly. Chlorophyll content, carotenoids content, and photosynthesis were at maximum level at 90 DAS. At various growth stages, phosphorus application at 75 mg P kg⁻¹ soil resulted in maximum amelioration of most of the parameters studied. It increased the seed-yield by 38.3%, seed-protein content by 14.9% and seed-carbohydrate content by 5.0%, relative to the control. It was concluded that there was a hidden hunger of hyacinth bean for phosphorus owing to soil-phosphorus deficiency that was ameliorated effectively by its basal dressing at 75 mg P kg⁻¹ soil.     

植物生理的研究在岩溶环境植被恢复中的应用

岩溶环境生态脆弱,影响了植(作)物对营养元素的吸收,妨碍了植(作)物的正常生长发育,做好岩溶地区的生态修复工作,最重要的就是该地区的植被恢复,这就需要选择岩溶环境适生植物,建立起具有生物多样性的稳定的岩溶森林生态系统,以保证系统能迅速地朝良性方向发展。而为了在众多植物种群中筛选出具有岩溶环境适生特性的品种,就需要首先对岩溶环境适生植物的生理特性诸如叶绿素荧光特性、碳酸酐酶活性、稳定碳同位素组成等作深入的研究,进而为建群种的选择提供一定的理论依据。     

不同光照条件下玉米碳酸酐酶活性差异比较与分析

[目的]比较不同光照条件下不同玉米品种碳酸酐酶（CA）活性的变化情况。[方法]以毕单系列玉米品种（毕单10、13、15、17、18号）为试材,待幼苗长至34叶时在不同光照条件（＂弱光＂、＂中光＂、＂强光＂）下培养,培养3 d后开始取样测定CA活性,研究不同处理玉米品种CA活性的变化规律。[结果]在＂弱光＂至＂中光＂段,随着光照强度的升高,各品种的CA活性逐渐升高,但在＂中光＂至＂强光＂段,各品种的CA活性普遍下降,其中毕单15号CA活性降幅最大,毕单18号CA活性降幅最小。＂弱光＂和＂中光＂处理各品种的CA活性差别较小,而＂强光＂处理各品种的CA活性差别较大。[结论]在一定范围内,供试玉米品种的CA活性随光照强度的增加而升高。     

Interactive effects of zinc and boron on growth,photosynthesis, and water relations in pistachio

The effects of zinc (Zn) and boron (B) on some physiological and biochemical characteristics of pistachio (Pistacia vera L. cv. Badami) seedlings were evaluated in a greenhouse study. It was found that both high levels (10 and 20 mg B kg^?1 soil) and also lack of B account for the reduction in growth and photosynthesis parameters, especially at low Zn levels. Moreover, Zn deficiency resulted in a reduction in the net photosynthetic rate and stomatal conductance. However, the adverse effects of B deficiency and toxicity were alleviated by increasing Zn levels up to 10 mg kg^?1 soil. In addition, provided that B and Zn are adequate, synergism can be observed between the two nutrients. This is because sufficient amounts B accelerated the effects of Zn by raising the plant dry weight, photosynthesis parameters, carbonic anhydrase activity, and chlorophyll contents. This increase was reported higher in comparison with Zn alone application. It was concluded that Zn may act as a scavenger of reactive oxygen species (ROS) for mitigating the injury on biomembranes under B stress. Adequate concentration of Zn also prevents uptake and accumulation of excess B in leaf by increasing membrane integrity of root cells. Similarly, B application in adequate concentration plays an important structural role in the cell wall and influences a great variety of physiological processes in pistachio seedlings.     

二氧化碳辅助发酵葡萄的干制和发酵工艺优化

为了开发经发酵前处理的新型葡萄干产品,该文以新鲜葡萄为原料,以发酵后葡萄总酚质量浓度与平均干燥速率为指标,在单因素试验基础上,利用正交试验设计对发酵葡萄的最佳发酵工艺条件进行了优化。利用福林酚法测定总酚质量浓度,用热风干燥箱进行干燥并测定平均干燥速率。结果表明:二氧化碳发酵葡萄的最佳工艺条件为:压强0.14MPa、温度36℃下发酵72h。该条件下的葡萄总酚质量浓度和平均干燥速率综合值可达最大,分别比不经处理的葡萄高48.3%和44.6%。说明二氧化碳发酵葡萄干是一种富含高总酚含量的新型产品,二氧化碳发酵后再干燥也是一种具有应用价值的新型干制工艺。     

Carbonic anhydrase and Na/K-ATPase activities at different molting stages of the giant freshwater prawn <Emphasis Type="Italic">Macrobrachium rosenbergii</Emphasis>

ABSTRACT:   In the present study, the role of carbonic anhydrase (CA) and Na/K-ATPase in the gill and epidermal tissues in the giant freshwater prawn Macrobrachium rosenbergii was examined as a function of molting stage. CA activity levels in the front and back gills were low at the intermolt stage C₀, but increased significantly at premolt stage D₃, and then decreased after molting. In the epidermal tissue, activity levels decreased gradually towards premolt to a minimum level at stage D₃, but became elevated at postmolt stages A and B. Na/K-ATPase levels in the front and back gills did not change significantly during the molt cycle. CA in the gill is possibly involved in supplying counter-ions for ion uptake, while CA in the epidermal tissue may play a role in mineralizing the exoskeleton after ecdysis. Na/K-ATPase in the gills may function in ion uptake from the ambient medium; however, since its activity was not influenced by the molt cycle, it probably does not have a major role in osmoregulation in the freshwater environment.