Metal Induced Inhibition of Photosynthesis,Photosynthetic Electron Transport Chain and ATP Content of Anabaena doliolum and Chlorella vulgaris:Interaction with Exogenous ATP

This study demonstrates a concentration dependent inhibition of carbon fixation, O2 evolution, photosynthetic electron transport chain and ATP content of A. doliolum and C. vulgaris by Cu, Ni and Fe. Although the mode of inhibition of photosynthetic electron transport chain of both the algae was similar, PS II depicted greater sensitivity to the test metals used. The toxicity in both organisms was Cu > Ni > Fe. A. doliolum was, however, more sensitive to Cu and Ni, and C. vulgaris to Fe. Toxicity was generally dependent on metal uptake, which in turn was dependent on their concentrations in the external medium. A partial restoration of nutrient uptake, carbon fixation, and enzyme activities following supplementation of exogenous ATP suggests that ATP regulates toxicity through chelation.

Heavy Metal Toxicity in a N_2-Fixing Cyanobacterium, Anabaena doliolum: Regulation of Toxicity by Certain Environmental Factors

The toxic effects of chromium and tin salts on growth, ^(14)C uptake, heterocyst differentiation, and nitrate reductase. nitrogenase, and glutamine synthetase activities of Anabaena doliolum and their regulation by pH. salinity, extracellular metabolites (spent), and organic acids have been studied. The toxicity of the test metals was lowered at alkaline pH and increased at acidic pH. NaCl at 20 mM was found to decrease metal toxicity. Extracellular metabolites (spent) in a 1:1 ratio(v/v) with fresh culture medium and organic acids were found to reduce metal toxicity. Among the various organic acids studied, humic acid was the most effective in regulating metal toxicity, apparently due to its multiple binding sites for metal cations. This study demonstrated that environmental factors.such as pH, salinity, extracellular metabolites, and organic acids, can mediate the toxicity of heavy metals to A. doliolum in a laboratory microcosm, (C)1990 Academic Press. Inc.

Impact of Spectral Quality on Toxicity of Iron in Anabaena Doliolum and Chlorella Vulgaris.

Evidence is presented on the effects of low and high concentrations of iron on growth, nutrient uptake (NH4+and NO3-), photosynthesis (CO2-fixation and O2-evolution) and nitrate reductase (NR) activity of A. doliolum and C. vulgaris under monochromatic irradiation. Control cultures (not treated with FeCl3) showed maximum growth under fluorescent followed by red, yellow, blue and green lights (fluorescent > yellow > red > blue > green). The inhibition was of synergistic type under yellow and red lights at all the iron concentrations tested. However, under blue and green lights the interaction was less than additive type. All the processes studied responded in a similar manner to a particular color of light. Under fluorescent light at low Fe concentrations, stimulation of NR, 14CO2-fixation and O2-evolution was noticed in both the test organisms. However, even the lowest concentration of iron tested was inhibitory to these processes under yellow and red lights. Under blue light at 20 μg-ml-1 Fe, NR activity was inhibited by 98%. This study clearly demonstrates that metal toxicity to phytoplankton will be greatly affected by spectral quality, hence it will have great significance in limnological research.

Protective Effects of Certain Natural and Synthetic Complexans on the Toxicity of Chromium and Tin to a N_2-Fixing Cyanobacterium, Anabaena doliolum

The effects of chromium and tin on survival, growth, carbon fixation, nitrate reduction, ammonia assimilation, and nitrogenase activity of a N_2-fixing cyanobacterium, Anabaena doliolum, and their amelioration by synthetic and natural complexans, viz., EDTA, nitrilotriacetic acid (NTA), pyridine dicarboxylic acid (PDA), and citrate, have been studied. Chromium proved to be much more toxic than tin, as it inhibited growth yield (49%), carbon fixation (53%), and nitrate reductase (79%), glutamine synthetase (30%), and nitrogenase activities (77%) at its sublethal concentration, whereas tin induced less inhibition of growth yield (42%), carbon fixation (50%). and nitrate reductase (66%), glutamine synthetase (32.4%), and nitrogenase activities (70%). Despite its inhibitory effects at 10μml^(-1), EDTA supplementation in metal-spiked medium counteracted the toxicity of chromium and tin more significantly than NTA, PDA, and citrate. When supplemented with LD_(50) of Cr, EDTA protected growth, carbon fixation, NR, GS. and Noase, respectively, by 32.6, 50.0, 33.3. 17.7. and 65.4%. However, EDTA-induced restoration of the above parameters at a sublethal concentration of tin was only 30.2, 50.0,28.1, 27.7, and 61.5%, respectively. Although NTA and citrate at 10/μgml^(-1) each were stimulatory to various processes of test cyanobacterium, they were comparatively less effective than EDTA in the amelioration of metal toxicity. On the basis of these observations, a generalized hierarchical sequence of protective efficiency of synthetic and natural cornplexing ligands may be given as EDTA > NTA > citrate > PDA. It seems plausible that the toxicity of various heavy metals may be regulated by a large array of organic complexing agents of the aquatic environment because they possess various metal binding sites. (c) 1989 Academic Press,lnc.

Curvularia martyniicola,a new species of foliicolous hyphomycetes on Martynia annua from India

In the micromycofloristic survey of some dematiaceous hyphomycetes from the Terai region of Uttar Pradesh(India),an undescribed species(C.martyniicola)of anamorphic fungus Curvularia Boedijn was found on living leaves of Martynia annua(Martyniaceae).The novel fungus is described,illustrated and discussed in details.The present species is compared with earlier reported similar taxon,and is characterized by longer conidiophores and conidia with less septa.A key is provided to all the species of Curvularia recorded on Martyniaceae and Pedaliaceae.The details of nomenclatural novelties were deposited in MycoBank(www.MycoBank.org).

Effect of Silver Nanoparticles on Growth of Eukaryotic Green Algae

Silver nanoparticles,endowed with powerful antimicrobial property,are the most widely used nanomaterial in consumer products,with associated risk of their easy access to environment and freshwater ecosystems by surface runoff.Although toxic effects of nanosilver on bacterial,fungal and mammalian cells have been documented,its impact on algal growth remains unknown.Pithophora oedogonia and Chara vulgaris are predominant members of photosynthetic eukaryotic algae,which form major component of global aquatic ecosystem.Here we report for the first time that nanosilver has significant adverse effects on growth and morphology of these filamentous green algae in a dose-dependent manner.Exposure of algal thalli to increasing concentrations of silver nanoparticles resulted in progressive depletion in algal chlorophyll content,chromosome instability and mitotic disturbance,associated with morphological malformations in algal filaments.SEM micrographs revealed dramatic alterations in cell wall in nanoparticle-treated algae,characterized with cell wall rupture and degradation in Pithophora.Although these observations underscore severe deleterious effects of nanosilver on aquatic environment,the information can also be exploited as a bioengineering strategy to control unwanted and persistent growth of noxious algal weeds that clog the municipal water supply and water channels and produce fouling of water bodies.

源自车辆的微粒磁性与Ficus infectoria(一个关键种)对它的改善

引言 源自车辆燃烧的磁性矿物质主要是磁铁矿和金属铁颗粒,大小为0.1～0.7 μm[1].这种大小的颗粒对人类特别有害,因为它能被吸入肺里.而且,在悬浮尘粒中,磁铁与其它重金属(如锌、镉、铬)[2]和对人体健康有害的诱变有机化合物[3]结合在一起.

Global diversity and distribution of distoseptosporic micromycete Corynespora Güssow(Corynesporascaceae):An updated checklist with current status

A review and updated checklist of Corynespora(Dematiaceous hyphomycetes)diversity and distribution reported from all over the world is prepared and presented over here based on available bibliographic survey upon published data.After critical review and verification,a total of 207 taxonomic records of Corynespora has been found in Index Fungorum,among them 179 spp.(86.47%)have been found as nomenclaurally valid/accepted taxa,while 14 spp.(6.76%)found to be transferred to other different taxa,11 spp.(5.31%)synonymously transferred to other Corynespora taxa,and 3 spp.(1.44%)found as invalid taxa.In all word-wide recorded Corynespora species,114 spp.(55.07%)have been found as foliicolous,90 spp.(43.47%)as lignicolous,2 spp.(0.96%)as lichenicolous,and 1 sp.(0.48%)from the air.Similarly,184 spp.(88.88%)have been reported on Angiosperms,1 sp.(0.48%)on Gymnosperms,22 spp.(10.62%)recorded on unidentified plant parts/taxa,whereas no one species recorded on Bryophytes and Pteridophytes.Likewise,166 spp.(80.19%)have been recorded on 54 families of Dicot,18 spp.(8.69%)on 6 families of monocot,1 sp.(0.48%)on 1 family of Gymnosperm,and 22 spp.(10.62%)on unidentified plant parts/taxa.Furthermore,the distribution of Corynespora spp.have been recorded from 34 countries,in which the species richness recorded maximum in India(80 spp.,38.64%)followed by China(31 spp.,14.97%),USA(11 spp.,5.31%),and other countries.Besides,distinguishing features of valid Corynespora spp.are also provided along with their hosts/substrate,host’s family,distribution(country),and references.This paper provides an updated checklist of Corynespora spp.reported from all over the world with their current status in the context of current nomenclature.In order to get all collected scientific information at one shop for further scientific study on exploration of Corynespora,this compiled up-to-date checklist with their comparative morphology would be vital and helpful to the researchers of concern fields as well as allied disciplines.

Corynespora celastri sp.nov.on Celastraceae from India

Corynespora celastri sp.nov.,is introduced on living leaves of Celastrus paniculatus(Celastraceae)collected from Paniyara forest of Mahrajganj,Uttar Pradesh,India.The new species is illustrated and compared with closely similar species reported on Celastraceae.This species is characterized by having longer conidiophores and conidia among the members reported on same host family.A key to all species of Corynespora on Celastraceae is also provided.

Impact of Land-Use Change on Soil Microbial Community Composition and Organic Carbon Content in the Dry Tropics

Restoration of forests poses a major challenge globally, particularly in the tropics, as the forests in these regions are more vulnerable to land-use change. We studied land-use change from natural forest(NF) to degraded forest(DF), and subsequently to either Jatropha curcas plantation(JP) or agroecosystem(AG), in the dry tropics of Uttar Pradesh, India, with respect to its impacts on soil microbial community composition as indicated by phospholipid fatty acid(PLFA) biomarkers and soil organic carbon(SOC) content. The trend of bacterial PLFAs across all land-use types was in the order: NF > JP > DF> AG. In NF, there was dominance of gram-negative bacterial(G^-) PLFAs over the corresponding gram-positive bacterial(G^+) PLFAs. The levels of G^- PLFAs in AG and JP differed significantly from those in DF, whereas those of G^+ PLFAs were relatively similar in these three land-use types. Fungal PLFAs,however, followed a different trend: NF > JP > DF = AG. Total PLFAs, fungal/bacterial(F/B) PLFA ratio, and SOC content followed trends similar to that of bacterial PLFAs. Across all land-use types, there were strong positive relationships between SOC content and G-, bacterial, fungal, and total microbial PLFAs and F/B PLFA ratio. Compared with bacterial PLFAs, fungal PLFAs appeared to be more responsive to land-use change. The F/B PLFA ratio, fungal PLFAs, and bacterial PLFAs explained 91%, 94%,and 73% of the variability in SOC content, respectively. The higher F/B PLFA ratio in JP favored more soil C storage, leading to faster ecosystem recovery compared to either AG or DF. The F/B PLFA ratio could be used as an early indicator of ecosystem recovery in response to disturbance, particularly in relation to land-use change.

Microbial Biomass Dynamics in a Tropical Agroecosystem： Influence of Herbicide and Soil Amendments

The influences of herbicide alone and in combination with the soil amendments with contrasting resource qualities on dynamics of soil microbial biomass C （MBC）, N （MBN）, and P （MBP） were studied through two annual cycles in rice-wheat-summer fallow crop sequence in a tropical dryland agroecosystem. The experiment included application of herbicide （butachlor） alone or in combination with various soil amendments having equivalent amount of N in the forms of chemical fertilizer, wheat straw, Sesbania aculeata, and farm yard manure （FYM）. Soil microbial biomass showed distinct temporal variations in both crop cycles, decreased from vegetative to grain-forming stage, and then increased to maximum at crop maturity stage. Soil MBC was the highest in herbicide ＋ Sesbania aculeata treatment followed by herbicide ＋ FYM, herbicide ＋ wheat straw, herbicide ＋ chemical fertilizer, and herbicide alone treatments in decreasing order during the rice-growing period. During wheat-growing period and summer fallow, soil MBC attained maximum for herbicide ＋ wheat straw treatment whereas herbicide ＋ FYM, herbicide ＋ Sesbania, and herbicide ＋ chemical fertilizer treatments showed similar levels. The overall trend of soil MBN was similar to those of soil MBC and MBP except that soil MBN was higher in herbicide ＋ chemical fertilizer treatment over the herbicide ＋ wheat straw treatment during rice-growing period. In spite of the addition of equivalent amount of N through exogenous soil amendments in combination with the herbicide, soil microbial biomass responded differentially to the treatments. The resource quality of the amendments had more pronounced impact on the dynamics of soil microbial biomass, which may have implications for long-term sustainability of rainfed agroecosystems in dry tropics.

Comparative response of seedlings of selected native dry tropical and alien invasive species to CO_(2) enrichment

Global climate change and ongoing plant invasion are the two prominent ecological issues threatening biodiversity world wide.Among invasive species,Lantana camara and Hyptis suaveolens are the two most important invaders in the dry deciduous forest in India.We monitored the growth of these two invasive species and seedlings of four native dry deciduous species(Acacia catechu,Bauhinia variegata,Dalbergia latifolia and Tectona grandis)under ambient(375–395μmol mol^(-1))and elevated CO_(2)(700–750μmol mol^(-1))to study the differential growth response of invasive and native seedlings.Methods Seedlings of all the species were exposed to ambient and elevated CO_(2).After 60 days of exposure,seedlings were harvested and all the growth-related parameters like plant height;biomass of root,stem and leaves;total seedling biomass;R/S ratio;allocation parameters;net assimilation rate(NAR)and relative growth rate(RGR)were determined.Important Findings Biomass,RGR and NAR of all the species increased under elevated CO_(2)but the increase was higher in invasive species and they formed larger seedlings than natives.Therefore under the CO_(2)-enriched future atmosphere,competitive hierarchies could change and may interfere with the species composition of the invaded area.

太阳紫外辐射增加对水生生态系统的影响

水生生物系统为人类提供大量的食物,其主要形式是鱼类、甲壳类和海藻。全球人类所消耗的动物蛋白质的30%以上来自于海洋,在很多国家,特别是发展中国家,这个比例还会大大增加。因此,了解大阳 UV—B辐射(280～315nm)的增加对水生生态系统产品的产量有怎样的影响是十分重要的。另外,海洋还在全球变暖的过程中起着重要作用。海洋浮游生物是大气中CO_2的主要的汇,对未来大气中CO_2浓度的变化趋势起着决定性作用。海洋生物系和陆地生物圈对CO_2的净吸收的相对重要性已成为当前很多研究项目的主要内容。浮游生物构成了水中各种其它生物赖以生存的食物链的基础。海洋中浮游生物在全球海洋中的分布并不均匀。研究发现,除了大陆架的涌升区域外,高纬度地区浮游生物的浓度最高,要比热带和亚热带地区浮游生物的浓度高10～100倍。除养分、温度、盐度和光照因素外,热带和亚热带地区经常发生的高强度太阳 UV—B辐射也是影响浮游生物分布的因素之一。某种主要的浮游生物数量的减少会严重影响到水生生态系统的复杂的食物链及食物的总产量。据测算,大气中臭氧含量耗损16%会导致浮游生物数量减少5%,也就等于全世界每年的鱼产量将减少700万t。要确定UV—B辐射量小的变化对生物的影响到底有多大可能是困难的,因为生物本身有很大的不确定性和变异,而且未能很好地确定臭氧减少前的浮游生物的产量。浮游生物生产局限于透光层,即水域的上层,因为这里有充足的阳光。有机物在透光层中的位置受风和海浪作用的影响。另外,很多浮游生物因活动能力强而增加了产量及生存能力。像人类一样,浮游生物不能察觉进而避免UV—B辐射。研究表明,太阳UV—B辐射对浮游生物的定向性和游动两方面均有影响,最终会导致这些有机物生存能力的降低。研究人员直接测量了UV—B辐射在南极水域的增加量和穿透性,并提供了臭氧变化对自然界浮游生物群落影响的结论性证据。利用与南极臭氧洞有关的UV—B辐射的时间和空间的变化特性,研究人员估算了臭氧洞所覆盖的范围内浮游生物的产量,并与洞外区域进行了比较。结果表明,由于臭氧的减少而导致的UV—B辐射的增加直接引起了浮游生物数量的减少。一项研究指出,在结冰带的边缘,浮游生物的这种减少量为6%～12%。近年来,UV—B辐射对藻类和海草的影响引起了人们的关注。与浮游生物相比,多数较大型的植物被固定在它们生长的地方,因此仅受到自己生长的地方的UV—B辐射的作用和影响。最近的研究已经证明,很多红色、褐色和绿色藻类不进行光合作用。人们还发现,大阳UV—B辐射对鱼虾蟹类、两栖类及其它动物早期发育阶段有损害作用。最严重的是降低它们的繁殖能力和损害幼体的成长发育。甚至在目前强度水平下,太阳UV—B辐射仍是一种限制因素,UV—B辐射量稍微增加便会导致一些有机物数量的大大减少。在高纬度地区(高于北纬40°)的晚春季节,UV—B辐射的增加可能会影响到一些物种,因为UV—B#射的增强恰好发生在它们生长发育的关键阶段。即使UV—B辐射很少量的增加或短期的波动也会很严重地影响较敏感的物种。最近的研究已经论述了氯氟烃化合物的替代物及其分解物的潜在影响。一些氢氟碳化合物(HFCs)和氢氯氟烃化合物(HCFCs),特别是HFC134a,HCFC123和 HCFC124降解并主要生成三氟醋酸(TFA)。TFA对大多数海洋和淡水中的浮游生物来说具有轻度的毒性,人们还在推测TFA是否会在食物链中聚集。即使TFA的生产维持到下一世纪,TFA也不会达到严重毒害整个海洋浮游生物的程度。然而在局部水生生物系统内,可能会达到剧毒的程度。虽然大量的资料证明,过量的UV—B辐射无疑对水生生态系统是有害的,但目前我们只能对其潜在危害作一个粗略的估计。

Plants: The Future Pharmaceutical Factory

The main objective of this study was to identify prospects, advantages and challenges of plant molecular farming. Plant-made pharmaceuticals (PMPs) and plant made vaccines (PMVs) were intended to be used for human consumption. A broad range of plants, including crops, vegetables and fruits have been investigated for their applicability in production of pharmaceuticals over the last two decades. At present, mainly maize, rice, tobacco and safflower are used in open field production. Contained bioreactor-type systems focus on moss, algae and plant organ culture. Expression systems include stable transformation of plant genomes—both nuclear and plastid, which are also used in the generation of genetically modified crops, plant-viruses and transient expressions. Each expression system (production platform) offers different advantages and disadvantages. Production platform choice is perceptive and depends on a broad range of criterion. This study is based on literature reviews, document analysis and internet database browsing.

Screening of antibacterial drugs from marine gastropod Chicoreus ramosus(Linnaeus,1758)

Objective:To screen the antibacterial drugs from different solvent extracts of tissue and egg of marine gastropods Chicoreus ramosus against clinically isolated human pathogenic bacteria.Methods:Vibrio parehaemolyticus(J13300),Aeromonus hydrophilla(IDH1585),Salmonella typhi(C6953),Salmonella paratyphi A(C6915),Vibrio cholerae(IDH5439)and Escherichia coli(H10407)using standard well diffusion method and its minimum inhibitory concentration.Results:Different solvent extracts of Chicoreus ramosus was screened for their activity against egg inhibited the growth of the tested pathogenic bacterial strains.The minimum inhibitory concentration of both the extract ranged from 4 to 12 mg/mL.The study revealed that the acetone and chloroform extract of both the tissues and Conclusions:These results suggest that marine gastropods tissue and egg extract contains comparatively good antibacterial activity.

Evaluation of thermostable endoglucanase in Paenibacillus lautus strain BHU3 for yield enhancement

In the present study,Paenibacillus lautus strain BHU3 isolated from landfill soil was evaluated for the presence of potential endoglucanases which are the first candidate of cellulase enzyme system to act on cellulose.In-silico analysis revealed high potential thermostable endoglucanases which can efficiently interact with cellulose.The most potent and thermostable endoglucanase(locus tag id.CPZ30_18280)belonged to glycosyl family-5 and had interaction energy of−12.981 kcal/mol for the best docked cluster containing three out of ten docking conformations,and Tm value of 73.3℃.MD simulation of 100 ns proved highly stable binding interactions of CPZ30_18280 endoglucanase with cellulose with root mean square deviation(RMSD)values ranging from 0.15 to 0.30 nm.Consistent interactions with characteristic active site residues(tyrosine,tryptophan and aspartate)of glycosyl family-5 endoglucanases were found.Further,to enhance the production of endoglucanases,the fermentation conditions were optimized employing approaches like one factor at a time(OFAT)and response surface methodology(RSM).Maximum activity of endoglucanase was determined at 60℃.The optimized condi-tions for enhanced production of endoglucanase(10.15 U/mL)were pH 6.63,yeast extract conc.3.44 g/L,wheat bran 3.59%,and inoculum size 2.65%.Hence,P.lautus strain BHU3 has enormous potential to synthesize highly efficient thermostable endoglucanases under optimized regime using agro-wastes.Thus,it could find immense industrial applications including large scale cellulose conversion to bioethanol.