Identification and pathogenicity study of emerging fish pathogens Acinetobacter junii and Acinetobacter pittii recovered from a disease outbreak in Labeo catla (Hamilton, 1822) and Hypophthalmichthys molitrix (Valenciennes, 1844) of freshwater wetland in West Bengal,India     

Ramesh Chandra Malick  Asit Kumar Bera  Hemanta Chowdhury  Manojit Bhattacharya  Tanuja Abdulla  Himanshu Sekhar Swain  Raju Baitha  Vikas Kumar  Basanta Kumar Das 《Aquaculture Research》2020,51(6):2410-2420

The disease outbreaks in aquaculture system of wetlands are the major cause of fish mortality. Among various bacterial septicaemic diseases, fish mortality caused by Acinetobacter spp. is recently reported in different fish species. Fish disease outbreak was investigated in a wetland of West Bengal, India to identify the aetiological factors involved. The moribund fish were examined and subjected to bacterial isolation. Two bacterial causative agents were identified as Acinetobacter junii and Acinetobacter pittii by biochemical characterization and 16S rRNA gene amplification. Both the isolates were oxidase‐negative, nitrate‐negative, catalase‐positive and indole‐negative. The molecular identification using 16S rRNA gene sequencing and phylogenetic tree analysis further confirmed the two Acinetobacter spp. with 97%–99% similarity. The antibiotic resistance patterns of these two bacteria revealed that both of them were resistant to β‐lactam, cefalexin, cephalothin, amoxyclav, cefuroxime, cefadroxil, clindamycin, vancomycin and penicillin. In addition, A. pittii was also resistant to other antibiotics of cephams group such as ceftazidime and cefotaxime. In the challenge experiment, both A. junii and A. pittii were found to be pathogenic with LD₅₀ of 1.24 × 10⁵ and 1.88 × 10⁷ cfu/fish respectively. Histopathological examination of gill, liver and kidney revealed prominent changes supporting bacterial septicaemia. The investigation reports for the first time on concurrent infection by A. junii and multidrug‐resistant (MDR)‐A. pittii as emerging fish pathogens to cause severe mortality in Labeo catla and Hypophthalmichthys molitrix in a freshwater wetland.  相似文献   

Changes in soil and water quality at sediment–water interface of Penaeus vannamei culture pond at varying salinities     

Ramamoorthy Saraswathy  Moturi Muralidhar  Das Sanjoy  Periyamuthu Kumararaja  Sukumaran Suvana  Natarajan Lalitha  Vinaya Kumar Katneni  Arunachalam Nagavel  Koyadan Kizhakedath Vijayan 《Aquaculture Research》2019,50(4):1096-1106

The health of the pond environment in shrimp farming is important for sustainable and profitable aquaculture, in which sediment–water interface is the most important influencing area. With this objective, the key parameters of water and sediment at the interface was studied in shrimp ponds with varying salinities and compared with the surface water and soil to understand the variations and the underlying causes. Total ammonia nitrogen and total alkalinity were higher in water at the interface as compared to surface water, whereas pH, nitrite, oxide forms of nitrogen (NO₃), phosphorus (PO₄) and oxidizing bacteria were observed to be lower. There was no significant difference with respect to macrominerals such as sodium, potassium, calcium and magnesium between water at the interface and surface. These changes are profoundly influenced by the uppermost 1.0‐cm thick sediment layer, where the maximum transition of nutrients takes place with the water column. The outcome of the study highlights the effectiveness of water sampling for metabolites at the interface, which reflects at an early stage any potential deterioration of pond environment, which will help the farmer to initiate timely mitigation measures.  相似文献   

Capturing genetic variability and selection of traits for heat tolerance in a chickpea recombinant inbred line (RIL) population under field conditions     

Pronob J. Paul  Srinivasan Samineni  Sobhan B. Sajja  Abhishek Rathore  Roma R. Das  Sushil K. Chaturvedi  G. R. Lavanya  Rajeev K. Varshney  Pooran M. Gaur 《Euphytica》2018,214(2):27

Chickpea is the most important pulse crop globally after dry beans. Climate change and increased cropping intensity are forcing chickpea cultivation to relatively higher temperature environments. To assess the genetic variability and identify heat responsive traits, a set of 296 F_8–9 recombinant inbred lines (RILs) of the cross ICC 4567 (heat sensitive) × ICC 15614 (heat tolerant) was evaluated under field conditions at ICRISAT, Patancheru, India. The experiment was conducted in an alpha lattice design with three replications during the summer seasons of 2013 and 2014 (heat stress environments, average temperature 35 °C and above), and post-rainy season of 2013 (non-stress environment, max. temperature below 30 °C). A two-fold variation for number of filled pods (FPod), total number of seeds (TS), harvest index (HI), percent pod setting (%PodSet) and grain yield (GY) was observed in the RILs under stress environments compared to non-stress environment. A yield penalty ranging from 22.26% (summer 2013) to 33.30% (summer 2014) was recorded in stress environments. Seed mass measured as 100-seed weight (HSW) was the least affected (6 and 7% reduction) trait, while %PodSet was the most affected (45.86 and 44.31% reduction) trait by high temperatures. Mixed model analysis of variance revealed a high genotypic coefficient of variation (GCV) (23.29–30.22%), phenotypic coefficient of variation (PCV) (25.69–32.44%) along with high heritability (80.89–86.89%) for FPod, TS, %PodSet and GY across the heat stress environments. Correlation studies (r = 0.61–0.97) and principal component analysis (PCA) revealed a strong positive association among the traits GY, FPod, VS and %PodSet under stress environments. Path analysis results showed that TS was the major direct and FPod was the major indirect contributors to GY under heat stress environments. Therefore, the traits that are good indicators of high grain yield under heat stress can be used in indirect selection for developing heat tolerant chickpea cultivars. Moreover, the presence of large genetic variation for heat tolerance in the population may provide an opportunity to use the RILs in future-heat tolerance breeding programme in chickpea.  相似文献   

Tillage and nitrogen management effects with sequential and ready-mix herbicides on weed diversity and wheat productivity     

Chaitanya Prasad Nath  Tapas Kumar Das  Kuldeep Singh Rana  Ranjan Bhattacharyya  Sangeeta Paul  Shashi Bala Singh 《国际虫害防治杂志》2018,64(4):303-314

In this experiment, weed management was studied in zero tillage (ZT) and conventional tillage (CT) wheat with and without crop residue and nitrogen (N). The treatment ZT with crop residue retention (R) and 75% of required N plus GreenSeeker? (GS)-aided N management (ZTRNGS) resulted in a reduction of density and dry weight of weeds compared to CT and ZT without residue. Sequential application of pendimethalin and sulfosulfuron (PMT-SSF) reduced the weed density and dry weight compared to the weedy check (WC). Importantly, the richness and diversity indices were high in ZTRNGS and in WC treatments. Greater wheat grain (5.11 t/ha) and biomass yield (13.31 t/ha) were observed in ZTRNGS than CT without residue and blanket split application of N (CTN). The treatment ZTRNGS recorded 14.1% and 16.9% higher gross and net returns, respectively, over CTN. This study demonstrates that surface retention of crop residue in ZT is more useful than residue incorporation under CT for effective weed control, improving crop yield and profitability.  相似文献   

Using chemical seed dormancy breakers with herbicides for weed management in soyabean and wheat          下载免费PDF全文

T K Das  D K Das 《Weed Research》2018,58(3):188-199

Variable dormancies result in periodicity in the germination of weeds and make weed control a repetitive practice. Under some conditions, repeated applications of selective herbicides can lead to the dominance of perennial weeds like Cyperus rotundus . Our hypothesis was that applying a chemical dormancy breaker (DB ) plus herbicide mixture would better control a mixture of weed species. Three experiments were designed to develop a cost‐effective DB treatment and to evaluate its dose with herbicides tank‐mixtures for effective weed management. KNO ₃ and gibberellic acid GA ₃ as dormancy breakers offered comparable effects, but KNO ₃ was more economical than GA ₃. KNO ₃ at a 6% concentration was more effective in promoting weed germination than a 3% concentration in soyabean. A combination of KNO ₃ (6%) and pre‐emergence pendimethalin 0.75 kg a.i. ha^?1 + imazethapyr 0.10 kg a.i. ha^?1 controlled annual weeds by 99% and reduced C. rotundus growth by 83%. This treatment gave significantly higher soyabean yield and net returns. Similarly, a tank‐mixture comprising of clodinafop 0.06 kg a.i. ha^?1 + metsulfuron 0.006 kga.i. ha^?1 was more effective against weeds than pre‐emergence tank‐mix application of pendimethalin 0.75 kg a.i. ha^?1 + carfentrazone‐ethyl 0.02 kg a.i. ha^?1 and isoproturon 0.75 kg a.i. ha^?1. The use of pre‐emergence tank‐mixture of pendimethalin 0.75 kg a.i. ha^?1 + imazethapyr 0.10 kg a.i. ha^?1 should exhaust seed/tuber bank if repeated and reduce the application cost of herbicides by 50% and the dose, residue and cost of pendimethalin by 25%.  相似文献   

A multi-environment trials diallel analysis provides insights on the inheritance of fumonisin contamination resistance in tropical maize     

José Maria Villela Pádua  Kaio Olímpio Das Graças Dias  Maria Marta Pastina  João Cândido de Souza  Valéria Aparecida Vieira Queiroz  Rodrigo Veras da Costa  Maria Beatriz Pereira da Silva  Carlos Alexandre Gomes Ribeiro  Claudia Teixeira Guimarães  Salvador Alejandro Gezan  Lauro José Moreira Guimarães 《Euphytica》2016,211(3):277-285

  相似文献   

Erratum to: Synthetic pyrethroids (Type II) and freshwater fish culture: Perils and mitigations     

A. K. Prusty  D. K. Meena  S. Mohapatra  P. Panikkar  P. Das  S. K. Gupta  B. K. Behera 《International Aquatic Research》2015,7(4):349-351

  相似文献   

Effect of efficient pectinolytic bacterial isolates on retting and fibre quality of jute     

Biswapriya Das  Kalyan ChakrabartiSagarmoy Ghosh  Bijan MajumdarSudipta Tripathi  Ashis Chakraborty 《Industrial Crops and Products》2012,36(1):415-419

Four bacterial strains with high balanced polygalacturonase (PG) and pectin lyase (PNL), and xylanase with minimal cellulase activity were used in jute retting. The 16S rDNA analysis revealed that the organisms were: Bacillus sp. L6 (GQ891097), Bacillus pumilus strain EK-17 (GQ891098), B. pumilus strain Geo-03-422 (GQ891103) and B. pumilus strain IK-MB12-518F (GQ891105). The microorganisms in different combinations of consortia showed synergistic effect resulting in increased PG (35.52-46.61 IU/g cell wet weight), PNL (39.79-72.12 U/ml), xylanase (0.705-0.840 μmol/ml/min) and little cellulase (0-0.153 μmol/ml/min) activities. The organisms in different combinations of consortia reduced the retting period from 11 to 13 days as compared to 19 days in the control. Microbial inoculation produced remarkable improvement in jute fibre strength (26.62-28.91 g/tex) and fineness (2.76-2.92 tex) over control. The pH of the post-retting water samples became acidic, and the electrical conductivity (Ec), chemical oxygen demand (COD) and hardness increased. The organisms could be adopted in industrial application for extraction of jute fibre.  相似文献   

Induction,purification and partial characterization of vitellogenin in an Indian major carp Catla catla (Ham.)     

Bipulendu Jena  Jyotirmaya Mohanty  Radha C Das  Sushil K Garnayak  Samiran Nandi 《Aquaculture Research》2013,44(12):1901-1911

Vitellogenin was purified from the serum of 17‐β estradiol (E₂)‐induced juvenile Catla catla using a simple two‐step purification procedure i.e. selective chemical precipitation followed by gel filtration chromatography. Purified protein migrated as single band in a native gradient PAGE which indicated the purity of the sample. The molecular weight of the native catla vitellogenin (~440 kDa) was determined using gel filtration chromatography. In SDS‐PAGE under reducing conditions catla vitellogenin dissociated into three major sub units at 115 kDa, 102 kDa and 73 kDa along with a few faint bands. Confirmation of purified protein as catla vitellogenin was supported by multiple physiological evidences, e.g. absence in male as well as juvenile sera and presence in matured female fish, ability to be synthesized upon estradiol injection in immature fish and certain unique biochemical properties like high molecular weight, phospholipoglycoprotein nature of the molecule. Western blot analysis showed that polyclonal antibody raised against purified protein detected vitellogenin in the sera of catla and in a few species selected from Cyprinidae family. These antisera were used to detect vitellogenin in liver tissue of hormone‐induced catla using immunohistochemistry and its applicability in other immunoassays is discussed.  相似文献   

Role of stalk-anatomy and yield parameters in development of charcoal rot caused byMacrophomina phaseolina in winter sorghum     

I. K. Das  Prabhakar  S. Indira 《Phytoparasitica》2008,36(2):199-208

Charcoal rot caused byMacrophomina phaseolina (Tassi) Goid. damages stalk tissue and weakens stalk strength, leading to lodging of crop and loss in grain yield in sorghum. In an attempt to understand the pathogenicity byM. phaseolina in relation to stalk characters and plant outputs, the effects of morphological (stalk-thickness), anatomical (bundle-number, bundle-density, and vascular tissue) and physiological characters (water and soluble sugar content) of the stalks of winter sorghum genotypes on charcoal rot development were analyzed. Bundle-number and stalk-thickness had a significant influence on internal spread of charcoal rot. A thicker stalk facilitated the spread of lesions more than did a thinner one. A stalk with densely packed vascular bundles inhibited lesion advancement. Field studies with 24 winter sorghum genotypes demonstrated that most of the parameters that could improve grain and stover yield also increased the length of charcoal rot lesions. Lesion development in stalks showed a high degree of association with grain yield (R²=0.51) and 100-grain weight (R²=0.42). The rate of symptom development in stalks differed during dough and maturity stages. It was concluded that anatomical characters of sorghum stalk, especially bundle-number, along with yield parameters played an important role in determining the extent of stalk damage by charcoal rot in winter sorghum. http://www.phytoparasitica.org posting March 25, 2008.  相似文献