Effect of Salinity Stress on Antioxidative Enzyme Activity in the Leaves of Tolerant and Susceptible Genotypes of Groundnut

Aims: To better understand the physiological and biochemical mechanisms in the light of antioxidative enzymes activity under salinity stress between tolerant and susceptible genotypes of groundnut. Study Design: Completely Randomized Design. Place and Duration of Study: The laboratory experiment was carried out in the departmental laboratory of Plant Physiology, Bidhan Chandra Krishi Viswavidyalaya (BCKV), Mohanpur, Nadia, and West Bengal during the year 2017-18. Methodology: A controlled study was conducted to screen 26 genotypes of groundnut under 200 mM NaCl salinity stress. Fourteen-day old seedlings were subjected to salinity treatment. For this, the modified Hoagland nutrient solution containing 200 mM NaCl (osmotic potential: -0.8 MPa) was applied in each case and the pH was adjusted to 6.3. The treatments were repeated on every third day. Control set without salinity stress was also maintained similarly in each case for comparison of results. Results: The salt tolerance index or STI of the genotypes ranged from 47.57% to 96.40%. Out of all the genotypes KDG-197 (STI= 96.40%) was found to be the most tolerant under a salinity stress of 200 mM NaCl and it was closely followed by R 2001-2 (STI=87.92%), VG 315 (STI=84.05%), TCGS 1157 (STI=77.59%) and TG 51 (STI=73.67%). While the genotypes Girnar 3 (STI= 47.57%), OG 52-1 (STI=49.09%), TVG 0856 (STI= 49.28%) and J 86 (STI= 50.66%) were the most susceptible genotypes based on their relative performance under stress in respect of total dry weight. It has been noted further that, out of the nine genotypes, enhancement of antioxidative enzyme like super oxide dismutase (SOD), guaiacol peroxidase (GPOX) and catalase (CAT) activity was recorded maximally in tolerant genotype KDG 197 (64.18%, 71.74% and 52.82% increase over control respectively) and R 2001-2 (53.68 %, 93.48% and 53.96 % increase over control respectively) but the activity of these enzyme in the four susceptible genotypes declined considerably under salinity treatment. Conclusion: Tolerant genotypes of groundnut in general registered much higher activities of antioxidative enzymes in their leaves as compared to the susceptible genotype under high salinity stress.

Isolation, identification, and optimization of laccase from Alternaria alternata

Laccase, lignin peroxidase, and manganese peroxidase have a synergistic effect on a wide range of recalcitrantcompounds. Among them, laccase is polyphenol oxidase widely available in fungi, plant species, and insects.Laccase has an important role in effluent decoloration, detoxification of pulp bleaching, and bioremediationprocess. Screening was carried out to find new fungal isolate for the presence of laccase activity with guaiacolas indicator compound. Sixteen fungal isolates were obtained from biodeteriorated agro waste and the woodsamples were collected from North Gujarat region of India. Among these isolates, one of the fungal isolateswas observed with good laccase activity and identified as Alternaria alternata. Laccase activity was determinedusing 2,2’-azinobis-(3-ethylbenzethiazoline-6-sulfonate) as substrate. Various production parameters such aspH, temperature, various carbon sources, nitrogen source, inducers, and cations were used to select the optimumcondition for further increase in the production of this enzyme. Maximum laccase activity was obtained withglucose and sucrose as carbon source, 0.2% ammonium sulfate as nitrogen source, and 0.06% Cu+2 with 1.5 mMveratryl alcohol as inducer under optimized condition.

Screening, Production and Partial Characterization of a Thermostable Laccase from Trametes sp. Isolate B7 with Biotechnological Potentials

The search for efficient and green oxidation technologies has increased interest in utilization of laccases in non conventional methods. Laccases catalyze a wide range of substrates due to low substrate specificity and strong oxidative potentials. Challenges to large-scale enzyme utilization include, low enzyme activity and instability which restrict use in many areas of biotechnology. In the study, 59 fungi comprising Aspergillus niger (40%), Trichoderma harzianum (31%), Aspergillus flavus (9.0%), Trichoderma viride (5.0%), Fusarium oxysporum (5.0%), Rhizopus stolonifer (5.0%), Trametes sp. (3.0%) and Aspergillus nidulans (2.0%) were isolated and screened for laccase production. Plate screening test showed 57.5%, 34.0% and 8.5% of fungi were laccase-positive on ABTS, Guaiacol, and α-naphthol agar respectively. Isolates were further screened in liquid cultures, and the highest laccase producer identified molecularly. Trametes sp isolate B7 was selected for solid state fermentation (SSF). Laccase production in SSF was highest at pH 5.0 (2356 U/mL). The purified laccase showed high activity (pH 3.0 - 6.0) and stability (pH 3.0 - 8.5) using ABTS. It was active (20 - 80°C) and thermostable (30 - 80°C) with optimum stability at 70°C (100% for 1 hour). The percentage decolourization of Phenol red were 28% and 36% using 1000 U/mL and 2000 U/mL crude laccases respectively. Similarly, RBBR (100%), Congo red (75%) and Malachite green (62%), and 77.4%, 64% and 28% were decolourized using 1000 U/mL and 2000 U/mL crude laccases respectively. ABTS agar was very reliable in large-scale screening for laccase which possessed thermostable property and degraded synthetic dyes without use of enzyme mediators. These attribute made the enzyme suitable for application in industry and biotechnology.

Screening of ligninase-producing bacteria from south east Pahang peat swamp forest soil

Aims: Research on lignin degradation capability is previously restricted exclusively to fungal enzymes. However, recent studies had successfully revealed several soil bacterial strains that were able to produce ligninolytic enzymes. These bacterial ligninolytic enzymes were claimed to be more specific in catalysing cleavage of certain linkages between phenolic units of lignin polymers as compared to fungal enzymes. The present study focuses on screening for ligninaseproducing bacteria isolated from South East Pahang Peat Swamp Forest (SEPPSF) soil using agar-based assay. Methodology and results: Thirteen isolates used in this study, which were selected based on distinctive colony morphology from our previous isolation work, showed decolourisation zone on Azure B plates screening. The ratio of decolourisation zones were measured to the ratio of the colony size and the biggest ratio was 2.22 by isolate AR1. Only 4 out of the 13 isolates were able to grow on lignin plates. Subsequently, the 4 isolates, AR3, AR8, AR10 and AR13 were tested on M1 agar supplemented with 3 ligninolytic enzyme indicator compounds which were tannic acid (TA), guaiacol and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) respectively. All four isolates showed growth on TA plates while only AR10 showed a clear brown coloration. An Intense reddish-brown colour formation was observed around the colony of isolates AR3 and AR10 on guaiacol plates while none exhibited green coloration around the colonies when tested on ABTS plates. Conclusions, significance and impacts of study: Isolate AR10 that was identified as Serratia sp. was perceived to be a potential ligninase-producer, though in-depth analysis has to be conducted in the future to determine the specific ligninolytic enzyme activities and characteristics. The application of different substrates is essential to investigate the ligninolytic potential and reaction of those bacterial enzymes towards different indicator compounds. This study is a preliminary endeavour concerning potential ligninolytic enzymes from bacteria as biocatalysts in various industrial processes. This is the first report on preliminary study for ligninolytic activities of soil bacteria from SEPPSF soil.

A New Method for Accurate Determination of Peroxidase Activity Based on Fluorescence Decrease of Guaiacol / 分析化学

At present the most common colorimetry for the activity determination of the peroxidase ( POD) is based on the detection of the absorbance of product at 470 nm in a reaction system of the H2 O2/POD/guaiacol ( GA) , but the shortcoming of the method is that the formed product is not stable and there is the serious adsorption phenomenon on the cell. To solve this problem, a new method was established for accurate determination of POD activity based on the fluorescent feature of GA. By using standard solutions of horseradish peroxidase as the test samples and under these optimum conditions such as 0. 5 mmol/L of GA, 0. 5 mmol/L of H2 O2 , pH 6, 0. 05 mol/L of phosphate buffer solution and the reaction temperature of 20℃, the sample volume was only consumed 20 microlitre at a time, the linear response range was 500-60000 U/L ( r=0 . 9993 ) , the detection limit was 385 U/L and relative standard deviation was ≤2 . 4% ( n=11 ) . The comparisons for the determination results of the POD activity in the white radish’s extraction solutions were conducted among our method (9714±132 U/L) and the colorimetric method (9926±352 U/L) as well as the recirculating-catalytic flow analysis ( 9608±456 U/L ) . The results showed that the mutual consistency is better.

Synthesis and elucidation structure of O-para dehydroguaiacol prepared by crude of Brassica oleraceae var alboglabra peroxidase-catalyzed oxidation.

Peroxidase was extracted from Brassica oleracea var alboglabra. The potential of crude Brassica oleracea var alboglabra peroxidase as a biocatalyst for the dimerization of guaiacol is presented. The products of the reaction were isolated and have been fully characterized by spectroscopic methods. One new coupling dimer of O-para dehydroguaiacol was obtained. Bioactive of this compound exhibited have strong antioxidant activity on DPPH radicals, with IC50 value of 4.69 μM.

Anestesia em cães utilizando éter glicerol guaiacol, quetamina e fentanil em infusão contínua intravenosa / Anaesthesia in dogs using continuous intravenous infusion of guaiphenesin, ketamine and fentanyl

Onze cães, sem raça definida, receberam como medicação pré-anestésica a anestesia induzida e mantida por infusão contínua intravenosa de quetamina e fentanil em solução de éter gliceril guaiacol a 5% em glicose a 5%, através de bomba de infusão. Em seis animais foram mensuradas frequência cardíaca e respiratória, ventilometria (volume corrente e volume minuto), pressão arterial (sistólica, média e diastólica), temperatura retal, hemogasometria arterial, saturação de 02 na hemogoblina, anion residual, osmolalidade sérica, concentração sérica total de 02, hematócrito, hemoglobina, glicose e eletrólitos. Avaliou-se também a analgesia através de pinçamento da pele da região glabra. Em outro grupo de cinco animais, onde foram realizadas três ovários-salpingo-histerectomias e duas osteossínteses, foram mensuradas a frequência cardíaca e respiratória e a resposta ao estímulo cirúrgico. Em ambos os grupos observou-se, principalmente, depressão respiratória dose-dependente, agravada com o uso de velocidade de infusão elevada, no caso de manobras cirúrgicas muito cruentas, como manipulação de periósteo.

Eleven mongrel dogs were premedicated with methotrimeprazine. Anaesthesia was induced and main-tained by continuous intravenous infusion of a 5% glucose solution containing guaiphenesin, ketamine and fentanyl. Heart and respiratory rates, tidal and minute volume, systolic, mean and diastolic blood pressure, temperature, arterial blood gases, hemoglobin oxygen saturation, anion gap, serum osmolality, serum oxygen concentration, packed cell volume, hemoglobin, glucose and electrolytes were measured in six dogs. Analgesia was investigated usind a forceps in the skin. In the other five dogs heart and respiratory rates and response to surgical stimulus were investigated. Respiratory acidosis, hypoximia and hypoventilation were observed. Respiratory depression was proportional to the infusion rate, particulary when high infusion rates were used for bone repair.