Laccases de Polyporus versicolor dans le sol et la litiere

Laecases of Polyporus versicolor in soil and litter. The laccases forms A and B, prepared from Polyporus versicolor, were compared with the laccases liberated from soil and litter by means ofchromatography on G100 Sephadex and DEAE DE 52 Cellulose. It appears that the soil and litter enzymes were of the form A that is strongly electronegative. These results suggest that because of their negative charges, laccases A, were weakly adsorbed onto humic colloids. Consequently, protection might be given to the active sites of the enzymes without preventing the formation of “humo-laccases” complexes in soil and litter.     

Chromatographie et purification des diphenol oxydases du sol

Neutral sterile and lyophilized extracts of fresh soil (NAFS Extract) degraded the following substrates: p-cresol: dl-3(3.4-dihydroxyphenylalanine)(dl DOPA): d(+) catechin and p-phenylcnediamine respectively (19.7); (5.3); (5.7) and (4.4) nmoles O₂ mg C^?1 min^?1 as specific activity (sp. act.). NAFS Extract was fractionated by G100 Sephadex column chromatography into two major peaks (K_D ~ 0 and ~ 1) without an increase in sp. act. DEAE DE 52 cellulose chromatography separated NAFS Extract into three fractions. The first fraction was free from humic acid, relatively homogeneous on polyacrylamide gel electrophoresis and had sp. act.: dl DOPA (17.2): d(+) catechin (8.5): p-phenylenediamine (22.9). The o- and p-diphenol oxidases which accompanied this fraction were well separated as complexes on G100 Sephadex column and were liberated by dialysis against distilled water. Following isolation, we obtained an o-diphenol oxidase on dl DOPA (23.4) and a laccase activity on p-phenylenediamine (33.8) in the free state; these activities being associated with nucleoprotein. Fractions (II) and (III) appeared to be relatively homogeneous in the form of “humic acid—enzyme complexes”. Specific activity were high in fraction (III): dl DOPA (10.8): d(+) catechin (0.7); p-phenylenediamine (5.4). The diphenol oxidase activity extracted from soil (NAFS Extract) was treated by salmine and SP Sephadex C25 to remove humic matter. The EFS Extract obtained had the following sp. act.: dl DOPA (14.0); p-phenylenediamine (6.3). This EFS Extract was separated into three fractions by means of G100 Sephadex column chromatography. The Kn were (I) ~0; (II) ~ 0.52; (III) ~ 1.3 respectively. The first fraction showed an increase of sp. act. only with p-phenylenediamine (9.1) and in the following two fractions the sp. act. were not augmented. The first fraction was further fractionated by means of DEAE cellulose chromatography into four fractions: the-first and the second had no activity on dl DOPA and p-phenylenediamine. The third was an o-diphenol oxidase on dl DOPA (11.0) with traces of laccase: p-phenylenediamine (0.7). The fourth was pure laccase: p-phenylenediamine (18.1). These results suggested that electrostatic, covalent and van der Waals forces contributed to the formation of humic acid enzymes complexes, associated in the tetramer to monomer forms of diphenol oxidases.     

Evaluation of fipronil nanoformulations for effective management of brown plant hopper (Nilaparvata lugens) in rice

In this paper, we report the development, characterization and bioefficacy evaluation of fipronil nanoformulations against brown plant hopper (BPH); Nilaparvata lugens in rice. Nanoformulations were characterized for nanosizing and stability under variable conditions. Bioefficacy of nanoformulations were evaluated under field condition at farms of Indian Agricultural Research Institute, New Delhi during Kharif 2015. At milking stage BPH populations were above economic threshold level; followed by foliar application of fipronil nanoformulations at four doses (viz., 30, 45, 60 and 90 g a.i./ha) along with commercial formulation of fipronil. The mean mortality clearly indicated that all the insecticidal treatments were significantly superior over untreated control where, highest mortalities were observed in nanodispersions followed by monolithic dispersion and commercial formulation of fipronil. Treated plots 7 days after application @ 60 g a.i./ha has shown 93.47%, 86.89% and 80.47% reduction BPH population in nanodispersion, encapsulated monolithic dispersion and commercial formulation treated plots respectively. In comparison to commercial formulation @ 60 g a.i./ha yield has increased by 0.56 t ha^?1 (28.76%) and 0.26 t ha^?1 (14.04%) in nanodispersion and monolithic dispersion.     

Variation in spawning responses, egg and larvae productions from induced rohu (Labeo rohita) during pre-monsoon and monsoon seasons: Relationship with hormonal changes and oocyte responsiveness during final maturation

Early induced spawning in captive rohu (Labeo rohita) often encounters with reduced spawning performances and devaluation of final product. The present study attempted to gain insight into the problems associated with poor performance of rohu during pre-monsoon spawning. A combination of sGnRHa and domperidone was used to induce final oocyte maturation (FOM) and ovulation in rohu during early (pre-monsoon, PM) and normal (monsoon, MN) spawning. The spawning performance parameters such as, spawning response, production and quality of egg and larvae showed significantly lower values (p < 0.05) in PM, when compared with MN spawning. The egg and spawn productions were recorded as 2.6 ± 0.05 and 2.41 ± 0.05 during the MN season, which were reduced by almost 50% in the PM season. Moreover the quality of egg and hatchling was devaluated significantly (p < 0.05) and exhibited higher percentage of mortality and abnormality in PM than those recorded in the MN season. The plasma concentration of carp gonadotropin (cGtH), 17β-estradiol (E) and 17α20β-dihydroxy-4-pregnen-3-one (DP) in relation to progress of FOM and ovulation at different seasons exhibited marked variation in hormonal profiles particularly in E and DP of PM fish. Higher initial plasma E (3.8 ± 0.3) and a distinct E peak clearly indicated the lack of transition from vitellogenic to post-vitellogenic stages that prevailed in PM rohu. Delayed DP and cGtH surge during FOM and ovulation resulted in longer latency period in spite of higher water temperature (31.5 °C) that prevailed during the PM period. In-vitro study on oocyte maturational competence (OMC) clearly depicted the lack of maturational competence in ovarian follicles during PM than MN in rohu. However priming the fish with purified carp gonadotropin (PCG) enhanced the acquisition of OMC in PM rohu in such an extent, that no marked seasonal differences (p > 0.05) in OMC were remained further, when compared with MN follicles. The PCG mediated acquisition of maturational competence was found to be dependent fully on new mRNA and protein synthesis in PM fish. The present study clearly demonstrated that the oocytes' unresponsiveness to hormonal induction was mainly responsible for reduced spawning performance in PM rohu, which could be ameliorated through PCG priming to achieve better spawning response in rohu during the pre-monsoon period. Thereby, the rohu fry production could be initiated successfully as early as May, allowing public and private hatcheries to produce larger age-0 rohu fingerlings ensuring reliable steady source of stocking materials for grow-out system earlier in the season.     

Different indices to characterize water use pattern of irrigated cauliflower (Brassica oleracea L. var. botrytis) in a hot sub-humid climate of India

Frequency and depth of irrigation play crucial role in crop yield and use efficiency of water resource. To test this hypothesis a field study was carried out in November to January of 2001-2002 to 2003-2004 on a sandy loam (Aeric haplaquept) for quantifying the frequency and depth of irrigation on growth, curd yield (CY) and water use pattern of cauliflower (Brassica oleracea L. var. botrytis). Four irrigation frequencies depending on the attainment of cumulative pan evaporation (CPE) values of: 25 (CPE₂₅), 31(CPE₃₁), 38 (CPE₃₈) and 45 (CPE₄₅) mm were placed in main-plots, with three depth of irrigation (IW) of 35 (IW₃₅), 30 (IW₃₀) and 25 (IW₂₅) mm in sub-plots. Water use efficiency (WUE), net evapotranspiration efficiency (WUE_ET) and irrigation water use efficiency (WUE_I) were computed. Marginal water use efficiency (MWUE) and elasticity of water productivity (EWP) were calculated using the relationship between CY and seasonal actual evapotranspiration (SET). A continuous increasing trend in growth parameters, yield and WUE_I was recorded with the increase in SET from CPE₄₅-IW₂₅ to CPE₃₁-IW₃₀. However with further increase in SET the same decreased up to CPE₂₅-IW₃₅ regime. Highest WUE and WUE_ET obtained under CPE₃₈-IW₃₅ regime where SET value was 5% lower than the status of SET under CPE₃₁-IW₃₀. This study confirmed that critical levels of SET needed to obtain maximum curd yield or WUE, could be obtained more precisely from the knowledge of MWUE and EWP.     

Nutrient shift in Parthenocissus tricuspidata seedling in response to soil water stress

A climate-controlled greenhouse experiment was conducted to determine the influence of soil water stress on the nutrient status of a climbing plant, Parthenocissus tricuspidata (Sieb.et Zucc) Planch. The results showed that water stress constrained N uptake more than P and K uptake in P. tricuspidata. Soil water supply significantly affected N efficiency ratio, but had no effect on P and K efficiency ratios. P. tricuspidata had low K concentration (<10 mg g⁻¹) in all its plant tissues, which allowed the plant to limit its stomatal opening and reduce its water loss. The study revealed that P. tricuspidata is able to adjust biomass distribution, nutrient uptake and nutrient use efficiency in response to soil water stress and that nutrient management for this plant under water stress should focus on N more than on P and K.     

Evaluation and impact assessment of culture‐based fisheries to enhance fish yield in small reservoirs in Odisha State,India

The present study investigates the success of stocking fingerlings of Indian major carps ‐Gibelion catla (Hamilton), Labeo rohita Hamilton and Cirrhinus mrigala Hamilton – to enhance fish yield in 58 small reservoirs in Odisha State, India. Fish stocking and yield data were collected from State Fisheries Department, Odisha. The relationships between area, stocking density and fish yield of different size groups of reservoirs were assessed using the Pearson correlation coefficient (r). Fish yield increased significantly (p < 0.05, t‐test) from 204 kg/ha/year in 2012–13 to 323 kg/ha/year in 2013–14 due to adoption of CBF. The corresponding per capita fish production increased from 398 kg fisher^?1 year^?1 to 702 kg fisher^?1 year^?1 benefitting more than 8,000 fisher households. Reservoirs in the size group 100–500 ha showed the highest response of fish yield with respect to stocking of fingerlings. The size of fingerlings at stocking and area of the reservoir had greater impact on enhancing fish yield. Stocking had a profound positive impact on fish yield. This study forms a baseline evaluation of the impact of stocking on small tropical reservoirs in India. It also recommends management measures and discusses issues, and the way forward for sustainable fisheries enhancement in small tropical reservoirs in eastern India.     

Etude des diphenol oxydases extraites d'une litiere de foret

Study of diphenol oxidases extracted from beech litter. Lyophilized neutral sterile extract from the fermentation (F) layer of beech litter (NALF Extract) exhibited the chemical characteristics of humic acids. It possessed diphenol oxidase activities. The specific activities (sp. act.), given in parentheses, are expressed in nmoles O₂ absorbed mg C^?1 min^?1: p-crcsol (19.5); catechol (0.6); dl-3(3,4-dihydroxyphenyl)alanine (5.7); d(+) catechine (4.8) and p-phenylenediamine (7.1). The NALF Extract was polydispersed by G100 Sephadex column chromatography. The firsi peak kd ~ 0.05 (fraction I), the intermediate band (fractions II + III) and the second peak k_d ~ 1.02 and 1.38 (fractions IV + V). Diphenol oxidases were localized in fractions I, II and III. Electrophoretic studies have shown that the fractions I, II and III are heterogeneous. Chromatography on DEAE cellulose of fraction I permitted the separation of 30 per cent of the laccase activity in a form which is free from humic material.     

Growth-promoting-Effekt von einigen fluoreszierendenPseudomonas-Isolaten auf Gurken (Cucumis sativus)

Zusammenfassung 209 Isolate von fluoreszierenden Pseudomonaden, die sich als Antagonistenin vitro gegenüberRhizoctonia solani undPythium aphanidermatum erwiesen haben, wurden hinsichtlich ihrer Wachstumsbeeinflussung bei Gurken untersucht. Von diesen Isolaten hatten 155 einen positiven Einfluß auf das Sproßgewicht. SiebenPseudomonas-Isolate reduzierten das Sproßgewicht zwischen 20 und 50%, 11 Isolate verursachten eine Sproßgewichtszunahme von 30 bis 50%, verglichen mit der unbehandelten Kontrolle.

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Growth-promoting effect of some isolates of fluorescent pseudomonas on Cucumber (Cucumis sativus)

209 isolates of fluorescent pseudomonas, which showed antagonismin vitro againstRhizoctonia solani andPythium aphanidermatum, were investigated for their ability to influence the growth of cucumber. Among them 155 isolates showed a positive effect on the sproutweight of cucumber. Even 7Pseudonomas-isolates reduced the sproutweight between 20 and 50%. Eleven isolates caused an increase of 30 to 50% of the sproutweight as compared with the untreated control.

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