Characterization of phyllosphere methylotrophic bacteria isolated from the groundnut and their impact on growth, yield and quality of the kernel

Aim: The present study was undertaken to characterize and evaluate the habitat adopted methylotrophic bacteria on groundnut growth and yield at field level.Methodology: Nine elite methylotrophic bacterial isolates were selected based on early plant growth promotion and quantified for plant growth promoting (PGP) traits along with one standard strain, Methylobacterium thiocyanatum DSM 11490T. Two field experiments were carried out with eleven different treatments arranged in a randomized block design with three replications. Bacterial inoculant was applied as seed treatment as well as foliar application at 35 and 70 days after sowing. Plant growth and yield parameters were estimated periodically and after harvest. Results: All the tested isolates exhibited multiple PGP traits. In Vriddhachalam, the yield of groundnut was significantly higher in Methylobacterium thiocyanatum VRI7-A4 (1688.9 kg ha-1) followed by Paenibacillus hunanensis COG-4 (1675.8 kg ha-1) compared to un inoculated control treatment. In Tindivanam, yield content of groundnut was found significantly higher in Methylobacterium thiocyanatum VRI7-A4 (1678.6 kg ha-1) followed by Pseudomonas psychrotolerans K-TMV7-6 (1667.5 kg ha-1). In addition, Methylobacterium inoculation increased the kernel protein content as compared to the control treatment in both the field experiments. Interpretation: The results showed that Methylobacterium populi TMV7-4, Methylobacterium thiocyanatum VRI7-A4, Pseudomonas psychrotolerans K-TMV7-6 may be used as bio-inoculant for groundnut crop

Temperature effect on behaviour, oxygen consumption, ammonia excretion and tolerance limit of the post larvae of shrimp Penaeus indicus.

The present study has been carried out to know the effect of temperature on behaviour, equilibrium loss and tolerance limit of the post larvae of shrimp Penaeus indicus. The experimental temperatures were selected based on the thermal tolerance limit. The experiments were conducted at a specific temperature for duration of 48 hr. The thermal tolerance experiments were conducted in two ways: in direct exposure and in gradually increasing temperature. The upper and lower lethal temperatures for the post larvae of shrimp P. indicus were 43.5 degrees C and 8 degrees C respectively. During tolerance experiment, no mortality was observed at 33 degrees C and 35 degrees C. But at 38 degrees C with gradual increase in temperature, 30% loss of equilibrium and mortality were recorded in 24.31 hrs and 25.07 hrs, and the remaining 70% were alive. On the contrary, when the post larvae of shrimps were directly exposed to 38 degrees C, almost 80% loss of equilibrium and mortality were recorded in 30.22 hrs and 30.40 hrs, remaining 20% were alive. At 40 degrees C with gradual increase in temperature, 100% loss of equilibrium and mortality were recorded in 25.32 hrs and 25.56 hrs. On the other hand, when the post larvae of shrimps were directly exposed to 40 degrees C, 100% loss of equilibrium was observed in 0.37 hrs and mortality in 1.40 hrs. These behavioral responses include an elevated temperature of 12 degrees C, surfacing, dashing against glass wall, jumping out of the water, etc. In general, the rate of oxygen consumption and ammonia excretion was found to enhance with increasing temperature. In the present study, it was found that gradual increase in temperature favours the shellfish population to escape from the thermal exposure as compared to direct exposure.

The influence of alpha-thalassaemia on the haematological & clinical expression of sickle cell disease in western India.

We evaluated the clinical and haematological features of 29 sickle cell anaemia patients with associated alpha-thalassaemia and 22 sickle cell homozygotes with a normal alpha-globin genotype from western India. The presence of alpha-thalassaemia resulted in significantly higher haemoglobin (Hb), haematocrit (HCT), red blood cells counts (RBC) and haemoglobin A2 (HbA2) levels but lower mean cell haemoglobin (MCH) and mean cell volume (MCV). The clinical presentation in these patients was also milder with fewer episodes of painful crisis, chest syndromes, infections, requirement of hospitalization and blood transfusions. However, splenomegaly was more common as compared to the patients with a normal alpha-globin genotype. It is evident from the present study that alpha-thalassaemia could be an important genetic factor modulating the clinical expression and haematological severity of sickle cell anaemia in this region.

Prenatal diagnosis of beta-thalassaemia mutations using the reverse dot blot technique.

BACKGROUND: Beta-thalassaemia is the most common genetic disorder among Indians and a number of mutations causing this disease have been reported. Since effective treatment of thalassaemia major is complicated and very expensive, prenatal diagnosis has become an important option for those at risk of having an affected foetus. We report the use of a rapid hybridization method called 'reverse dot blot' for detection of specific mutations of the beta-globin gene. METHODS: DNA was obtained from a 12-week-old foetus by chorionic villus sampling and was amplified using specific primers by the polymerase chain reaction and analysed by the reverse dot blot test. Results were available within 36 hours after sampling. RESULT: The father and mother were found to be heterozygous for codon 15 (G-A) mutation of the beta-globin gene. The foetus was normal. CONCLUSION: Reverse dot blot is a rapid and reliable technique for mutation detection in the beta-globin gene and can be useful for antenatal diagnosis.

Lactate dehydrogenase isozyme patterns in the denervated quail (Coturnix coturnix japonica) muscles.

Polyacrylamide gel electrophoresis of the Japanese quail (Coturnix cotunix japonica) muscle extracts revealed a single lactate dehydrogenase isozyme. A month after surgical unilateral brachiotectomy (denervation) there was significant atrophy of the triceps, biceps and radius ulnar muscles accompanied by the appearance of an additional lactate dehydrogenase isozyme band. This extra band may be the result of the synthesis of a new lactate dehydrogenase isozyme. This new isozyme exhibited a lower affinity for lactate, less sensitivity to urea denaturation and was more thermostable than the lactate dehydrogenase of normal (innervated) quail muscles. Based on these properties, it is suggested that the newly synthesised isozyme of the denervated muscles is LDH-1 ,(or B4/H4) type. Brachiotectomy also resulted in significant quantitative changes in the total lactate dehydrogenase activity of innervated muscles of the same animal.

Ultrastructural variations in frog muscles subjected to sciatectomy.

Fine structural variations in two different types of muscles of frog (Rana cyanophlictis) subjected to sciatectomy were studied electronmicroscopically. Gastrocnemius muscle showed marked myofibrillar disarray and degeneration due to sciatectomy, while sartorius muscle was relatively less affected. The extent of sciatectomy induced fine structural variation was in proportion to the degree of denervation atrophy (as reflected by loss of wet muscle weight) in these muscles. Differences in the degree of degenerative changes in atrophying muscles may be attributed to variations in fiber type composition and stretch effects imposed during swimming movements.

Changes in ascorbic acid content and acetylcholinesterase activity in the muscle of frog following sciatectomy.

Unilateral-sciatectomy for three months in the frog, Rana cyanophlictis resulted in a substantial increase on unit weight basis in the ascorbic acid (ASA) and dehydroascorbic acid (DHA) contents of the sciatectomized gastrocnemius muscle. Diketogulonic acid (DKA) levels did not vary. On whole muscle-weight basis only the ASA level increased. The AChE activity in sciatectomized muscle is significantly lower than that of the control. Partially purified preparation of the AChE from the sciatectomized muscle showed different kinetics compared to that from innervated control. In vitro additions of ASA in physiological concentration to the enzyme assay medium inhibited the AChE activity significantly and the inhibition was an un-competitive type. Reduced activity of the enzyme has been correlated to the increased concentration of ASA in the sciatectomized muscle.

Electrocardiographic changes on sublethal poisoning of Vacor and Silmurin to Bandicota bengalensis.

A single sublethal dose of Vacor (1 mg/rat) or Silmurin (50 microgram/rat) brought about dissimilar changes in cardiac physiology of bandicoot rats. Delayed myocardial repolarization and stress on cardiac tissues were noticed. Elevation of S-T segment above the isoelectric axis diagnostic of recent myocardial infarction was observed. Vacor and Silmurin induced differential changes in heartbeat; Vacor poisoning resulted in bradycardia, whereas Silmurin tachycardia. It is inferred that Vacor deaths may be due to bradycardia associated with atrioventricular block and that of Silmurin to delayed myocardial repolarization and tachycardia.

Synthesis in vitro of cholesterol by mitochondria in the shrimp Penaeus aztecus (Ives).

The incorporation of [ 14C ]-acetate, [ 14C ]-mevalonate and [ 14C ]-desmosterol into cholesterol in the muscle mitochondria of the brown shrimp Penaeus aztecus (Ives) is more as compared to that in hepatopancreas. [ I4C ]-Desmosterol is more efficiently incorporated into cholesterol in comparison with [ 14C ]-acetate. The muscle mitochondria from males incorporated more [ 14C ]-mevalonate into cholesterol than those from females, while the converse is true in the hepatopancreatic mitochondria.

Non-competitive inhibition of serum acetylcholinesterase (E.C.3.1.1.7) by vacor (N-3-pyridyl methyl-N'-P-nitrophenyl urea) in bandicoot rats.

Single dose (1 mg/rat) administration of VACOR (N-3-pyridyl methyl-N'-nitrophenyl urea) produced significant paralytic symptoms in rats. Such rats which lived for one week were sacrificed and serum AChE was extracted and purified by Sephadex column chromatography. The serum enzyme from the normal rats showed the existence of two isozymes on polyacrylamide gels which could be resolved through column chromatography. Both the isozymes showed non-competitive inhibition with VACOR in vitro; but to a varied degree. The ACh concentration increased by 70-75% in serum and 95-100% in erythrocytes of the poisoned rats. VACOR thus affects ACh hydrolysis thereby causing an accumulation of ACh in the serum of poisoned rats.

Ca2+-ATPase activity and lipid composition of sarcoplasmic reticulum of the gastrocnemius muscle of denervated frog.

Abnormalities have been noticed in the phospholipid and cholesterol composition of the atrophied gastrocnemius muscle of frog denervated for 1 month. Cholesterol : phospholipid molar ratios in the muscle increased on denervation. Sphingomyelin and cardiolipin fractions increased in contrast to phosphatidyl choline, phosphatidyl serine and phosphatidyl ethanolamine in the sarcoplasmic reticulum (SR) of denervated muscle. Na-azide sensitive Ca2+ ATPase activity of the mitochondria did not alter whereas that of SR decreased on denervation. Phospholipase C digestion impaired the organelle Ca2+-ATPase activity. The above abnormalities in enzyme activities have been correlated to the changes in the lipid composition of the denervated muscle. On the basis of these changes it is discussed that the primary change in the muscle due to denervation is the change in the permeability of the membrane.