Total Dehydrogenase Activity Research Articles

Effect of water regimes on seed quality parameters of rice (Oryza sativa L.) grown under aerobic and wetland conditions

A field experiment was conducted to know the effect of water regimes on seed quality parameters of rice and the was conducted by using factorial randomized complete block design, with two genotypes (BI-33 and Jaya) and two planting methods (Aerobic and Wetland). The resultants seeds were taken to conduct laboratory experiments pertaining to seed quality attributes and the studies revealed that the BI-33 under aerobic condition had shown a significantly higher seed quality with respect to germination (99%), mean seedling length (26.75cm), seedling dry weight (10.42 mg), SVI-I (2648) and SVI-II (1032) , highest total dehydrogenase activity (0.53 OD @ 480nm), highest amylase activity (14.67 %), highest total soluble protein content (7.15%) and recorded less EC (70.95 ?Sm-1/ppm). The experimental results revealed that both the genotypes and method of planting contribute for seed quality of the genotypes which were grown under different water regimes. The genotype grown under aerobic condition was better in seed quality parameters compared to wetland condition.

Ellagic acid protects against arsenic toxicity in isolated rat mitochondria possibly through the maintaining of complex II.

Chronic arsenic exposure has been linked to many health problems including diabetes and cancer. In the present study, we assessed the protective effect of ellagic acid (EA) against toxicity induced by arsenic in isolated rat liver mitochondria. Reactive oxygen species (ROS) and mitochondrial membrane potential decline were assayed using dichlorofluorescein diacetate and rhodamine 123, respectively, and dehydrogenase activity obtained by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide conversion assay. Arsenic increased ROS levels and mitochondrial dysfunction, which led to a reduction in mitochondrial total dehydrogenase activity. Mitochondria pretreated with EA exposed to arsenic at various concentrations led to a reversal of ROS production and mitochondrial damage. Our results showed that mitochondria were significantly affected when exposed to arsenic, which resulted in excessive ROS production and mitochondrial membrane disruption. Pretreatment with EA, reduced ROS amounts, mitochondrial damage, and restored total dehydrogenase activity specifically associated with mitochondrial complex II. EA protective characteristics may be accomplished particularly throughout the mitochondrial maintenance either directly by its antioxidant property or indirectly through its maintaining of complex II. These findings also suggest a potential role for EA in treating or preventing mitochondria associated disorders.

Effect of integrated nutrient management and spacing on seed quality parameters of black gram cv. Lbg-625 (rashmi)

A field experiment was conducted to assess the response of nutrient levels and spacing on seed quality attributes of black gram cv. LBG-625 (Rashmi). Experimental results revealed that fertilizer application of 50:100:100 + Black gram rhizobia (250 g ha-1) + PSB- Bacillus megaterium (250 g ha-1) recorded highest test weight (39.27 g), germination (90.60%), root length (15.77 cm), shoot length (13.43 cm), mean seedling length (29.20 cm), mean seedling dry weight (57.99 mg), seedling vigour index-I (2656), seedling vigour index-II (525), total dehydrogenase activity (0.998), protein content (23.16%), field emergence (86.56 %) lowest electrical conductivity (0.813 dSm-1) were superior over other fertilizer treatments. Among the planting geometry 60 x 10 cm recorded more germination per cent (90.48 %) compared to 45 x 10 cm (87.64 %) and 30 x 10 cm (86.91 %). Interaction of nutrient levels and spacing through the application of 50:100:100 + black gram rhizobia (250 g ha-1) + PSB- B. megaterium (250 g ha-1) with planting geometry 60 x 10 cm recorded more mean seedling length (34.40 cm), mean seedling dry weight (58.30 mg),and field emergence (90.24 %) lowest electrical conductivity (0.776 dSm-1) compared to control. The application of 50:100:100 + Black gram rhizobia (250 g ha-1) + PSB- B. megaterium (250 g ha-1) with planting geometry 60 x 10 cm were considered as seed quality improvement approach in blackgram, therefore conjunctive use of inorganic fertilizers and biofertilizer may be suggested for higher seed quality parameters along with overall betterment of crop.

The effects of the unsaturated degree of long-chain fatty acids on the rumen microbial protein content and the activities of transaminases and dehydrogenase in vitro

AbstractThis study investigated the effects of the degree of unsaturation (unsaturity) of long-chain fatty acids on microbial protein content and the activities of transaminases and dehydrogenase in vitro using goat rumen fluid as the cultural medium. Six types of fatty acids, stearic acid (C18:0, group A, control group), oleic acid (C18:1, n-9, group B), linoleic acid (C18:2, n-6, group C), α-linolenic acid (C18:3, n-3, group D), arachidonic acid (C20:4, n-6, group E), and eicosapentaenoic acid (C20:5, n-3, group F), were tested, and the inclusion ratio of each fatty acid was 3% (w/w) in total of culture substrate. Samples were taken at 0, 3, 6, 9, 12, 18 and 24 h, respectively, during culture for analyses. Compared with stearic acid, linoleic acid, α-linolenic acid, and arachidonic acid increased the bacterial protein content, while oleic acid and eicosapentaenoic acid had no significant effects; the protozoal protein content was reduced for all the unsaturated fatty acids, and the magnitude of the reduction appeared to be associated with the degree of unsaturity of fatty acids. The total microbial protein content was dominantly accounted by the protozoal protein content (about 4–9 folds of the bacterial protein), and only increased by linoleic acid, but reduced by oleic acid, arachidonic acid and eicosapentaenoic acid. There were no significant effects in the activities of both glutamic oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) for all the other fatty acids, except for arachidonic acid which enhanced GOT activity and oleic acid which enhanced GPT activity. The total dehydrogenase activity was positively correlated with the degree of unsaturation of fatty acids. In conclusion, the inclusion of 3% of long-chain unsaturated fatty acids increased bacterial protein content, whereas reduced protozoal protein content and enhanced dehydrogenase activity. The fatty acids with more than three double bonds had detrimental effects on the microbial protein content. This work demonstrates for the first time the effect rule of the unsaturation degree of long-chain fatty acids on the rumen microbial protein in vitro.

Influence of maturity stages and post-harvest ripening on seed quality in chilli genotypes

The present study was conducted at Department of Seed Science and Technology, University of Agricultural Sciences, Gandhi Krishi Vignana Kendra, Bangalore during 2011-12 to reveal the influence of maturity stages and post-harvest ripening on seed quality among ten (Bhut jolokia, Merkera local, Sweet baccatum, Gandhari, Biligiri local, Majjige menasu, Chinense habanero, Hot cherry, Cherry pepper and Shivani) chilli genotypes belonging to Capsicum chinense, C. frutescence and C. annuum . The results revealed that among maturity stages, fruits harvested at red ripe stage and subjected for 20 days post-harvest ripening (M 4 ) has recorded higher seed quality parameters viz., 1000 seed dry weight (6.95 g), seed germination (66.0 %), seedling length (9.9 cm), seedling dry weight (1.50 mg), seedling vigour index-I (748), total dehydrogenase activity (1.314), α-amylase activity (34.9 μg maltose ml -1 min -1 ) and field emergence (56.0 %). Also minimum electrical conductivity (1.743 dSm -1 ) and moisture content of fresh seed (10.93 %) was noticed.

Alterations in Protein and Isozymes Profiles during Accelerated Ageing in Soybean (Glycine Max(L.) Merrill)

This study was done to observe alterations in protein and isozyme profiles for soybean (Glycine max (L.) Merrill), during accelerated aeging. During the aeging period some physiological (percent germination, seedling vigour index and germination index) and biochemical (electrical conductivity, malonaldehyde content, total soluble sugars, total soluble proteins, peroxidase and dehydrogenase activity) changes were also observed in relation to seed vigour and viability in fresh and aged soybean seeds. Results showed an overall decrease in germination, vigour, soluble sugars and soluble protein content with increase in ageing duration. Increased activity of lipid peroxidation and electrical conductivity coupled with significant reduction in activities of peroxidase and dehydrogenase were noticed in accelerated aged seeds. Alterations in protein and isozymes profiles in aged seeds compared to fresh seeds indicated that the loss in seeds quality might be due to the adverse effect of ageing on proteins. The electrophoretic variations in protein and isozymes noticed in this study could be used as a criterion in assessing the quality of soybean.

Bioremediation potential of glyphosate-degrading Pseudomonas spp. strains isolated from contaminated soil.

Bacterial strains capable of utilizing glyphosate as the sole carbon source were isolated from contaminated soil by the enrichment culture method and identified based on partial 16S rRNA gene sequence analysis. Pseudomonas spp. strains GA07, GA09 and GC04 demonstrated the best degradation capabilities towards glyphosate and were used for the laboratory experiments of glyphosate bioremediation. Inoculating glyphosate-treated soil samples with these three strains resulted in a 2-3 times higher rate of glyphosate removal than that in non-inoculated soil. The degradation kinetics was found to follow a first-order model with regression values greater than 0.96. Cell numbers of the introduced bacteria decreased from 4.4 × 10(6) CFU/g to 3.4-6.7 × 10(5) CFU/g dry soil within 18 days of inoculation. Due to the intense degradation of glyphosate, the total dehydrogenase activity of the soil microbial community increased by 21.2-25.6%. Analysis of glyphosate degradation products in cell-free extracts showed that glyphosate breakdown in strain GA09 was catalyzed both by C-P lyase and glyphosate oxidoreductase. Strains GA07 and GC04 degraded glyphosate only via glyphosate oxidoreductase, but no further metabolite was detected. These results highlight the potential of the isolated bacteria to be used in the bioremediation of GP-contaminated soils.

Improvement of the chilling tolerance of ‘Monika’ cucumber seedlings by short-term temperature and seed conditioning with plant growth regulators

ABSTRACT The aim of the present study was to improve the chilling tolerance of cucumber seedlings. The conditioned seeds in solutions of salicylic or jasmonic acid in concentrations of 10-2, 10-3 or 10-4 M or brassinolide in concentrations of 10-6, 10-8 or 10-10 M were subjected to temperature shock of 0, 2.5, 5, 35, 40 or 45°C for 1, 2 or 4 hours. Seedlings with 3 mm roots were chilled at 0°C for three days. The chilling susceptibility was evaluated by measurements of roots lengths, electrolyte leakage and total dehydrogenase activity. The obtained results indicated that cucumber tolerance to chilling conditions depended on the plant growth regulators used during seed imbibition and its concentration as well as the temperature initiating thermal shock and its duration. The highest tolerance to chilling, expressed by the subsequent growth of roots, was observed after seed conditioning in salicylic acid solutions in a concentration of 10-4 M for 16 h at 25°C, then exposed for 4 h to a shock temperature of 5°C. The length of seedling roots after such treatment was over 12 times longer than the control (imbibed in distilled water and not subjected to short-term temperature impact). An increased chilling tolerance of cucumber seedlings may result from enhanced membrane integrity and total dehydrogenase activity. Further research is needed to explain the mechanism of the positive effects of salicylic acid, jasmonic acid or brassinolide application to reduce the injurious effects of chilling on cucumber seedlings.

Allelopathic control of freshwater phytoplankton by the submerged macrophyte Najas minor All

Water blooms in eutrophic waters have been serious environmental problems in recent years. To explore effective measures to control this issue has been an interest of research. Our current study was designed to investigate the effects of submerged macrophyte Najas minor All. exudates on the growth of four freshwater phytoplankton species, toxic Microcystis aeruginosa, toxic Anabaena flos-aquae, Chlorella pyrenoidosa and Scenedesmus obliquus as well as natural phytoplankton assemblages of pond water. We also conducted a reciprocal response between N. minor and toxic M. aeruginosa using coexistence experiments. Our results showed that: (1) N. minor exudates significantly inhibited the growth of toxic M. aeruginosa, toxic A. flos-aquae and S. obliquus, with M. aeruginosa being the most sensitive, followed by toxic A. flos-aquae, and S. obliquus the least. N. minor exudates did not show inhibitory effect on C. pyrenoidosa; (2) N. minor and toxic M. aeruginosa have reciprocal inhibitory effect, and the allelopathic interactions between the two different organisms are density dependent and affect their mutual growth; (3) N. minor exudates also can induce a decrease in chlorophyll a content and an inhibition in total dehydrogenase activity of the phytoplankton assemblages. Our present studies indicated the submerged macrophyte N. minor might be a potential useful tool to control phytoplankton blooms.

Drought-stress-induced corky tissue formation in sapota fruit cv. Cricket ball is linked to enhanced “reverse flow”

Corky tissue (CT) of sapota fruit cv. Cricket ball is a physiological disorder caused by reduced seed viability during the early phase of fruit growth on the tree. The reduction of seed viability was found associated with a loss of moisture from fruit leading to CT formation. However, the exact process by which moisture is lost from fruit has not been determined yet. The principal aim of this study, therefore, was to determine the mode of water loss from fruit and to delineate the mechanism by which moisture loss influences corky tissue formation in sapota fruits. Experiments with developing sapota fruits treated with radioactive tritiated water (1H3) established the movement of water away from fruit to the subtending shoot buds by the process of “reverse flow”. The reverse movement of water from fruit to developing shoots contributed to a fall in seed total dehydrogenase (TDH) activity and a consequent reduction in the hydrolysis of starch in the mesocarp. The concurrent loss of calcium from pulp along with the efflux of water gave rise to structural and compositional changes in the pulp resulting in the development of CT in sapota. The study has provided confirmatory evidence for the movement of water away from fruit and established the occurrence of enhanced reverse flow in sapota during CT development. The present study is the first report demonstrating the occurrence of the phenomenon of reverse flow in sapota and describing how it influences the process of CT development in sapota.

Possible role of growth regulators in adaptation to heat stress affecting partitioning of photosynthates in tomato plants

The formation of polyribosomes and total dehydrogenase activity in rye grains from different harvest years (with different viability) were studied. It was found using actinomycin D and cordycepin that grain aging was related to a lower ability for RNA synthesis and polyribosome formation. At least part of the stored form of RNA (preformed mRNA) in the embryos of both aged non-viable grain was able to form complexes with ribosomes.

Metabolism of aged seeds. Changes in rye embryo polyribosomes during seed aging

Germination, total dehydrogenase activity, ribosomal proteins and ribonucleic acids of embryos obtained from winter rye harvested in different years and of distinctly differing viability were studied. Diminishing viability was accompanied by declines in the amount of ribosome-bound mRNA and a drop in the intensity of its synthesis during germination. Electrophoretic analysis of control embryo (fully viable) ribosome proteins revealed 55 different bands: 10 acidic and 45 basic. The embryos of aged seeds had 43 different bands of which 8 were acidic, 35 basic and almost all of which had an altered electrophoretic mobility as compared with the control sample. As aging progressed, the percentages of lysine, histidine and arginine increased while those of tyrosine, methionine, proline and serine decreased.

Dependence of the legume seeds vigour on their maturity and method of harvest

Several methods were used to study 'the vigour and viability of legume seeds <em>(Pisum sativum </em>L. cv. Hamil, <em>Piston arvense </em>L. cv. Mazurska and <em>Lupinus luteus </em>L. cv. Tomik) harvested at three main stages of seed repening (green, wax and full). The seeds were tested immediately after harvest (series A) and after two weeks of storage in pods (series B). It was found that: 1) the vigour of ripening legume seeds increases with maturation; 2) post-harvest storage in pods increases the degree of ripeness and. consequently. vigour; 3) seeds attain full vigour later than full viability; 4) seed leachate conductivity method gives erroneous results in assessing the vigour of immature seeds: 5) full vigour of maturing seeds of various degrees of ripeness can be determined by simultaneous application of both biological (eg. seedling growth analysis, VI) and biochemical (e.g. total dehydrogenase activity) methods.

The metabolism of aged seeds. The involvement of the pentose phosphate pathway in respiration in germinating rye grains of various ages

Winter rye grains from different harvest years (having distinctly different viabilities) were studied in terms of germination, total dehydrogenase activity and growth analysis. Reduction of seed vigor and viability was accompanied by a decrease in the intensity of embryo respiration during germination. The use of (1-<sup>14</sup>C) glucose and (6-<sup>14</sup>C) glucose showed that germinating rye embryos catabolize glucose through glycolysis, Krebs cycle and the pentose phosphate pathway. It was also shown that the C<sub>6</sub>/C<sub>1</sub> ratio in respiring embryos initially increased during the first 48 hours of germination, then dropped, which suggests a mounting contribution of the PP pathway to the overall cotabolism. The oxidation of glucose in, embryos from the most deteriorated grains proceeded through glycolysis and Krebs cycle only.

The metabolism of aged seeds. The formation of polyribosomes in germinating field bean ( Vicia faba sp. minor) seeds of different ages

Total dehydrogenase activity and formation of polyribosomes in embryonic axes and cotyledons of field bean seeds from different harvest years were studied. <sup>3</sup>H-uridine incorporation experiments showed that seed ageing was accompanied by decreased capability for RNA synthesis and polyribosome formation. The embryonic axes of seeds with reduced vigor contained lower levels of polyribosomes.

Conservation Tillage Influence on Carbon Dynamics Under Mediterranean Conditions

Intensity of tillage practices can enhance organic matter decomposition, increasing CO2 emissions from soil to the atmosphere. Conservation tillage (CT) has been proposed as a means of counteracting potential damages to the environment. In this study the effects of two CT systems, reduced tillage in a long-term experiment (RTL) and no-tillage in a short-term experiment (NTS), were compared to traditional tillage (TT) in the long (TTL) and short-term experiments (TTS). CO2 fluxes, total soil organic carbon (SOC) and dehydrogenase activity (DHA) were evaluated at 0-5, 5-10 and 10-15 cm depths throughout the three years studied (Oct. 2006-Jul. 2009). Traditional tillage increased CO2 emissions compared to CT. The CT treatments (RTL and NTS) accumulated more SOC in the surface layer (0-5 cm) than the TT treatments (TTL and TTS). SOC accumulation was moderate but DHA consistently increased in CT in the surface soil, especially with a legume crop included in the crop rotation. Values of stratification ratio of all parameters studied were higher in the CT treatments (RTL and NTS). The agricultural and environmental benefits derived from CT make this system recommendable for semi-arid Mediterranean rain-fed agriculture.

Microbial Structure and Functions of Biofilm During Wastewater Treatment in the Dairy Industry

ABSTRACTThe microbial structure and activity of biofilm are two important parameters for the successful operation and control of fixed film processes in wastewater treatment. However, the constant interaction between fixed and suspended biomass requires the parallel investigation of these two biological components. The aim of the present article is to study the key microbiological and enzymological parameters of biofilm and suspended biomass from an anaerobic sequencing batch biofilm reactor for dairy wastewater treatment. The effectiveness of organic matter (measured as COD) removal and nitrates removal was determined. The microbial structure of biofilm and suspended biomass was investigated by the quantity of anaerobic heterotrophs, anaerobic spore-forming microorganisms and denitrifying bacteria. The total dehydrogenase activity and the nitrate reductase activity were used as indicators for biomass activity. The obtained data showed that the enzyme activity of the fixed biomass was higher in comparison with that of the suspended biomass. This result is related to the more heterogenic media of the inert carrier and more dynamic conditions in the biofilm inner layers. The total dehydrogenase activity of the fixed biomass was four times higher and the nitrate reductase activity of the fixed biomass was two times higher than that of the suspended biomass during stable biofilm functioning. The investigated biological system mineralized the organic matter with high effectiveness (to 90%) and removed 67% of the nitrates from dairy wastewater as a result of the controlled water treatment process.

Analogous Modeling of Nutrient Transformation in Iskar River Sediments at Different Moisture Content: Microbiological and Enzymological Indicators

ABSTRACTThis study was focused on the R&D of the elements of the systems for early warning of risk events as well as on the selection of the mechanisms and indicators for their management. The aim was to derive the mathematical dependences, bioalgorithms, and indicative correlations for upgrading of the HSPF hydrological model. For this purpose analogous modeling of transformation of organics in the river sediments of the parafluvial zone as a function of moisture (in%) was performed. This upgrading can be applied for correct and effective prognosis of the rate of self-purification in the Iskar River in the section from Beli Iskar Reservoir to Iskar Reservoir.The results showed that the combination of total dehydrogenase, nitrate reductase and phosphatase activities could be considered an effective instrument for water quality management and for prediction of the rate of transformation processes. The derived linear mathematical dependences can be applied to calculate other microbiological and kinetic indicators important for monitoring, as well as to create special modules for the HSPF model with a well-functioning verification strategy.

Viscosity dictates metabolic activity of Vibrio ruber.

Little is known about metabolic activity of bacteria, when viscosity of their environment changes. In this work, bacterial metabolic activity in media with viscosity ranging from 0.8 to 29.4 mPas was studied. Viscosities up to 2.4 mPas did not affect metabolic activity of Vibrio ruber. On the other hand, at 29.4 mPas respiration rate and total dehydrogenase activity increased 8 and 4-fold, respectively. The activity of glucose-6-phosphate dehydrogenase (GPD) increased up to 13-fold at higher viscosities. However, intensified metabolic activity did not result in faster growth rate. Increased viscosity delayed the onset as well as the duration of biosynthesis of prodigiosin. As an adaptation to viscous environment V. ruber increased metabolic flux through the pentose phosphate pathway and reduced synthesis of a secondary metabolite. In addition, V. ruber was able to modify the viscosity of its environment.

Asymmetric Response of Carbon Metabolism at High and Low Salt Stress in Vibrio sp. DSM14379

Energy redistribution between growth and maintenance in salt-stressed cells is especially important for bacteria living in estuarine environments. In this study, Gram-negative bacterium Vibrio sp. DSM14379, isolated from the estuarine waters of the northern Adriatic Sea, was grown aerobically in a peptone-yeast extract medium with different salt concentrations (ranging from 0.3% to 10% (w/v) NaCl). Carbon flux through the central metabolic pathways was determined at low and high salt concentrations. At low salt concentrations, total endogenous respiration, dehydrogenase activity, and net intracellular adenosine triphosphate (ATP) concentration significantly increased, the phosphofructokinase and pyruvate kinase activity decreased, whereas glucose-6-phosphate dehydrogenase activity remained unchanged. The carrying capacity of bacterial culture decreased dramatically, indicating a severe metabolic imbalance at low salt concentrations. At high salt concentrations, carrying capacity decreased gradually. There was a large increase in glucose-6-phosphate dehydrogenase activity, which correlated with a 10-fold increase in concentration of osmoprotectant L-proline. There was no significant change of net intracellular ATP concentration, phosphofructokinase, or pyruvate kinase activity. The results indicate that Vibrio sp. DSM14379 central metabolic pathways respond to low and high salt concentrations asymmetrically; cells are better adapted to high salt concentrations. In addition, cells in the stationary phase can tolerate induced salt stress without a significant change in dehydrogenase activity or endogenous respiration for at least 1 h, but need to alter their macromolecular composition and carbon flux distribution for long-term survival.