Suppressive effect of secondary metabolites from Streptomyces plumbeus isolate F31D against Fusarium oxysporum f. sp. lycopersici,the causal agent of Fusarium wilt of tomato

Journal of General Plant Pathology - Fusarium wilt of tomato, a disease caused by the soilborne fungus Fusarium oxysporum f. sp. lycopersici, causes major losses to tomato production. Chemical...     

Growth response to increasing doses of microencapsulated vitamin B12 and related changes in tissue vitamin B12 concentrations in cobalt-de cient lambs

AIM: To investigate growth responses of cobalt-deficient lambs to increasing doses of microencapsulated vitamin B₁₂, and to measure associated changes in serum and liver vitamin B₁₂ concentrations over 243 days.

METHODS: From a flock grazing pastures that had low cobalt (Co) levels (about 0.06 mg Co/kg dry matter), 4-6-week-old lambs (n=137) were assigned to four groups and received either no treatment or a subcutaneous injection of 3.0, 4.5 or 6.0 mg of microencapsulated vitamin B₁₂ on Day 1. At approximately monthly intervals, all lambs were weighed and blood samples were collected from a selection (n=10) of monitor animals, up to Day 243. Liver biopsies were also carried out on the monitor lambs (n=8) on Days 1, 124 and 215.

RESULTS: The vitamin B₁₂-treated lambs grew significantly faster (p<0.001) than untreated animals. Liveweights after 243 days were 28, 45, 45 and 47 kg for the untreated, 3.0, 4.5 and 6.0 mg vitamin B₁₂-treated lambs, respectively. Of the initial group of untreated lambs, 68% had to be removed before the end of the trial because of substantial weight loss, but none of the treated animals were similarly afflicted. Serum vitamin B₁₂ concentrations increased in all vitamin B₁₂-treated lambs, reaching a peak at Day 25, and those of the 4.5 and 6.0 mg vitamin B₁₂-treated lambs remained significantly higher (except at Day 124) than the untreated lambs to Day 187. However, at Day 124, but not Day 215, the liver vitamin B₁₂ concentrations of treated lambs were two to three times higher than those of controls.

CONCLUSIONS: The growth rates of Co-deficient lambs were markedly improved by injection of 3.0, 4.5 or 6.0 mg of microencapsulated vitamin B₁₂, and liveweights were maintained for at least 243 days. Serum vitamin B₁₂ concentrations were related to this growth response; concentrations of <220 pmol vitamin B₁₂/l were associated with a 95% probability that lambs were Co-deficient and would thus respond to Co/vitamin B₁₂ supplementation. Based on these data, the current New Zealand reference criteria for Co deficiency should be reviewed.

CLINICAL SIGNIFICANCE: An injection of 3 mg microencapsulated vitamin B₁₂2 given to lambs at tailing will treat Co deficiency and will increase and maintain liveweights in a flock for up to 8 months.     

Endometritis impairs luteal development, function, and nitric oxide and ascorbic acid concentrations in buffalo (Bubalus bubalis)

A vast majority of the world buffalo resource is concentrated in tropical and subtropical countries. Apart from heat stress and poor nutritional availability, endometritis is one of the most commonly encountered reproductive problems limiting fertility and consequently productive potential of the species. As demonstrated recently, endometritis impairs growth and follicular fluid composition of the largest follicle in buffalo. In the present study, the effect of endometritis on luteal development, function, nitric oxide (NO), and ascorbic acid was investigated. Reproductive tracts were collected from 90 cyclic buffaloes at an abattoir and grouped into endometritic (n?=?36) or non-endometritic (n?=?54) buffaloes based on physical examination of uterine mucus, white side test, and uterine cytology. Samples with pus-containing mucus, positive reaction on white side test, and/or >5 % neutrophils were considered to be positive for endometritis. Corpora lutea were enucleated, weighed, classified into stages I to IV, and assayed for progesterone (P₄), NO, and ascorbic acid concentrations. Endometritic buffaloes had lesser (P?<?0.0001) luteal weight and P₄, NO, and ascorbic acid concentrations than non-endometritic buffaloes. The findings indicated that endometritis impairs corpus luteum development and function in buffalo. Reduced luteal NO and ascorbic acid concentrations during endometritis are novel findings.     

Effects of soil application of fly ash on the fusarial wilt on tomato cultivars

A study was carried out in microplots to evaluate the effect of fly ash on the plant growth and yield of tomato cultivars, Pusa Ruby, Pusa Early Dwarf and New Uday, and on wilt disease caused by Fusarium oxysporum f.sp. lycopersici . Fly ash was applied to soil by broadcast or in rows at the rate of 1, 2, 3 and 4 kg ash m-2 in place of inorganic fertilizers. In control plots, NPK (about 40 : 20 : 20 kg acre-1) and compost were added in place of fly ash. Ash application greatly increased the soil contents of P, K, B, Ca, Mg, Mn, Zn, carbonates, bicarbonates and sulphates. Plants grown in the ash-treated plots, especially at 3 or 4 kg dose, showed luxuriant growth and greener foliage, and plant growth and yield of the three cultivars were significantly increased in comparison with the plants grown in plots without fly ash. The wilt fungus, F. oxysporum f.sp. lycopersici at the inoculum level of 2 g plant-1 caused significant suppression of growth and yield in all three cultivars. Application of fly ash, however, checked the suppressive effect of the fungus, leading to a significant increase in the considered variables compared with the inoculated control. Soil population of the fungus (colony-forming units g soil-1) gradually decreased with an increase in ash dose. Row application was found to be relatively more effective in enhancing the yield of tomato cultivars and suppressing the wilt disease. The greatest increase in the yield of fungus inoculated and uninoculated plants due to broadcast or row application at 3 or 4 kg ash m-2 was recorded in tomato cv. Pusa Ruby (39 - 61 and 9 - 24%), followed by Pusa Early Dwarf (31 - 61 and 17 - 34%) and New Uday (21 - 35 and 4 - 22%).     

Effect of Temperature on the Seasonal Incidence of Shootfly,Atherigona naqvii in Wheat at Jaipur,India

Abstract

Seasonal incidence of shootfly, Atherigona naqvii Steyskal was studied in wheat sown on nine dates at approximately fortnightly intervals from 1 October to end of January during the 1973–74 to 1976–77 seasons at Jaipur, India. During the season the pest remained more active from the second fortnight of October to mid-December and again during February and March. These fluctuations appear to have a positive correlation with maximum and minimum temperatures while relative humidity and rainfall did not have any influence. The winter low temperatures during mid-December to mid-February arrested the flies' activity. The crop sown between mid-November and mid-December was found to be almost free from shootfly and no control measures are needed. However, early and late sown crops remained prone to attack.     

Interactive Effect of GA_3 ,N and P Ameliorate Growth, Seed and Fibre Yield by Enhancing Photosynthetic Capacity and Carbonic Anhydrase Activity of Linseed： A Dual Purpose Crop

Linseed (Linum usitatissimum L.) is an important dual-purpose, industrial crop. Its seeds are used for the extraction of oil and stem for fibres. However, the production of linseed is not going parallel with the increasing demand of its products. The present work was carried out with an aim to find out whether exogenous application of gibberellic acid (GA3) with or without graded levels of nitrogen (N) and phosphorus (P) could improve the performance of three linseed genotypes Parvati, Shekhar and Shubhra together with minimizing the costly fertilizer input and losses. Four combinations of N and P, viz., 0 mg N+0 mg P kg-1 soil (N0P0), N13.4 P4.46 , N26.8P8.94 and N40.2P13.4 were constituted. Half dose of each combination was applied basally at the time of sowing and remaining half dose was given at 40 d after sowing (DAS) as foliar spray along with 10-6 mol L-1 GA3 . Prior to sowing, the seeds of each linseed genotype were grouped in to two, one group of seeds was soaked in 0 mol L-1 GA3 (control) and the other group was soaked in 10-6 M GA3 solution, each for 8 hours. Treatments were comprised of (i) 0 mol L-1 GA3+N0P0 (T0 , control), (ii) 10-6 mol L-1 GA3 + N13.4P4.46 (T1), (iii) 10-6 mol L-1 GA 3 +N 26.8 P 8.94 (T2) and (iv) 10-6 mol L-1 GA3+N40.2P13.4 (T3). The crop performance was assessed in terms of growth, physiological and biochemical parameters at 60 and 75 DAS and yield attributes at harvest (175 DAS). The results showed a parallel increase in most of the parameters with increasing levels of N and P. However, application of 10-6 mol L-1 GA3 in association with N26.8P8.94 proved best, it enhanced seed yield, oil yield and fibre yield by 83.3, 97.3 and 78.7%, respectively accompanied with increase in net photosynthetic rate, carbonic anhydrase activity and dry matter accumulation. Among the genotypes tested, Shubhra performed best, while Parvati the least for most of the parameters studied. Thus, combined application of 10-6 mol L-1 GA3 plus N26.8P8.94 proved best and can be recommended to exploit the linseed as a dual-purpose crop for good yield of seed and fibre.     

Understanding the effects of intramuscular injection and feed withdrawal on Salmonella Typhimurium shedding and gut microbiota in pullets

Background:Gut microbiota plays a key role in health,immunity,digestion,and production in layers.Factors such as environment,diet,diseases,stress,and flock management significantly affect gut microbiota;however,it is not known how potential stressors such as intramuscular injections or feed withdrawal alter the composition of gut microbiota that result in increased the shedding level of foodborne pathogens.In the current study,the effects of intramuscular corticosterone injection and feed withdrawal were evaluated to understand their role in Salmonella Typhimurium shedding and changes in the composition of gut microbiota in layers.Results:Salmonella shedding was observed for 8 weeks post-infection.There was a significant increase in Salmonella Typhimurium count after intramuscular injection and feed withdrawal.The Salmonella infected and the negative control groups showed significant differences in the abundance of different genera in gut microbiota at week 1 and up to week 7 post infection.The infected group showed a significant reduction in alpha diversity of gut microbiota.Firmicutes reduced significantly(P<0.05)after intramuscular injection,while the feed withdrawal groups did not cause any significant changes in Proteobacteria-Firmicutes ratio.Furthermore,intramuscular injection resulted in a significant change in alpha diversity of gut microbiota.Conclusions:Exposure of chicks to relatively low dose of Salmonella Typhimurium can lead to persistent shedding in pullets.The Salmonella Typhimurium infection disrupted the gut microbiota composition immediately after infection.The potential stress of intramuscular injection and feed withdrawal significantly increased the Salmonella Typhimurium count in faeces.The intramuscular injection also resulted in a significant alteration of the Proteobacteria-Firmicutes ratio,which could increase the risk of dysbiosis.     

Large granular lymphocytes in the oviduct of developing and hormone-treated chickens.

1. In the present study the distribution of large granular lymphocytes (LGLs) and influence of oestrogen on these cells was investigated in the oviduct of chickens by the observation of H and E stained sections. 2. The LGLs first appeared in the oviduct at 9 weeks and their frequency of occurrence increased with age and was highest in the infundibulum and vagina from 21 to 32 weeks of age. The frequency of occurrence of LGLs from magnum to uterus (glandular part) was low. These cells were located at the base, middle and apical parts of the lining epithelium as well as in the sperm-storage glandular epithelium. 3. When chickens of 21 weeks were treated with DES, LGLs abundantly infiltrated in the oviducal epithelium in comparison to the control. 4. These results suggested that the development of LGLs in the oviduct of chickens correlates with oestrogen secretion.     

Environmental Factors Affecting the Release and Dispersal of Ascospores of Mycosphaerella citri

ABSTRACT Greasy spot, caused by Mycosphaerella citri, produces a leaf spot disease affecting all citrus species in Florida and the Caribbean Basin. M. citri produces pseudothecia and ascospores, which are considered the principal source of inoculum, in decomposing leaves on the grove floor. In studies using a computer-controlled environmental chamber, a single rain event triggered release of most mature ascospores beginning 30 to 60 min after the rain event. Additional rain events did not bring about further release. High relative humidity without rain triggered release of low numbers of ascospores, but vibration and red/infrared irradiation had little or no effect on ascospore release. After three to four cycles of wetting and drying of leaves, all pseudothecia had matured and released their ascospores. In the field, ascospores were detectable starting about 2 h after the beginning of a rain or irrigation and most ascospores were released within 16 h. Ascospore release was greatest following rain events and somewhat less following irrigations, and low numbers of ascospores were detectable on days without precipitation. Ascospore numbers declined linearly with horizontal distance from the source and as a function of the logarithm of ascospore numbers with vertical distance. Low numbers of ascospores were detected 7.5 m above the ground and 90 m downwind from the grove. Ascospore release can be advanced by irrigating frequently during dry, nonconducive conditions to stimulate ascospore release when environmental conditions are unfavorable for infection, but the eventual effects on disease severity are uncertain.     

Insecticidal activity of 23 essential oils and their major compounds against adult Lipaphis pseudobrassicae (Davis) (Aphididae: Homoptera)

Essential oils from 23 species of plants comprising 14 genera and 4 plant families were obtained by Clevenger-type water distillation. The major compounds in these essential oils were identified with GC-MS and their insecticidal activity against adult turnip aphids, Lipaphis pseudobrassicae (Davis), tested with dosage-mortality bioassays. We examined mortality only for viviparous adults because sizeable aphid populations on crucifer (Brassicaceae) hosts are largely produced by these wingless, parthenogenic females. Twenty-two of the oils were directly applied to aphid females in randomized blocks at concentrations of 0.0, 1.0, 2.5, 5.0 and 10.0 mg ml(-1). Essential oils mixed with a non-toxic emulsifying agent, dimethyl sulfoxide (DMSO), more easily penetrated the waxy insect cuticle. Probit analysis and LC(50) at three different exposures showed aphids were quickly incapacitated and killed by aliphatic aldehydes, phenols and monocyclic terpenes contained in Bifora and Satureja oils and at applied concentrations as low as 0.3 to 1.0 mg ml(-1). Only enough Pimpinella isaurica oil and its three phenylpropanoid fractions were available for testing at a single concentration of 10 mg ml(-1). We could not spare any additional P. isaurica oil for testing at other concentrations. Phenylpropanoids isolated from P. isaurica oil when recombined or left naturally blended in the oil were highly bioactive against L. pseudobrassicae at 10 mg ml(-1).