Regulatory and functional interaction of vasoactive factors in the kidney and extracellular pH

Regulatory and functional interaction of vasoactive factors in the kidney and extracellular pH. A growing body of evidence suggests that vasoactive factors produced in the kidney such as nitric oxide, endothelins, angiotensin, and prostaglandins participate actively in the regulation of acid-base homeostasis under physiologic conditions. In addition, recent reports indicate that alterations in the systemic acid-base status may also influence the generation of vasoactive cytokines in the kidney, which in turn may mediate the renal effector processes that tend to restore normality under such conditions. Metabolic acidosis, which so frequently accompanies many forms of chronic renal failure (CRF), may contribute to down-regulation of intrarenal nitric oxide production that characterizes CRF. Reduced extracellular pH inhibits inducible nitric oxide production in mesangial cells by altering the reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) oxidation, an important posttranslational mechanism in the inducible nitric oxide synthase (iNOS) activation. The underlying defects resulting in the uncoupling of NADPH oxidation in acidemic microenvironment are discussed. Acidosis stimulates renal production of endothelins, which mediate proximal tubular acidification by enhancing sodium-hydrogen exchanger-3 (NHE-3) activity. Renal endothelins mediate enhanced urinary acid excretion following dietary acid ingestion, an effect that is effectively blocked by endothelin receptor blockers. Reduced extracellular pH stimulates endothelin secretion from renal microvascular endothelial cells, which may promote enhanced acid excretion from the distal tubule under conditions of acidosis. These phenomena as well as the role of angiotensin and renal prostaglandins in mediating renal acidification in normal and acidotic conditions are discussed in this review, which describe the regulatory interaction between extracellular pH and renal vasoactive factors

Impact of Climate Change on Pest Management and Food Security

Climate change and global warming will have serious consequences for the diversity and abundance of arthropods, and the extent of losses due to insect pests, which will impact both crop production and food security. Prediction of changes in geographical distribution and population dynamics of insect pests will be useful for adapting pest management strategies to mitigate the adverse effects of climate change on crop production. Pest outbreaks might occur more frequently, particularly during extended periods of drought, followed by heavy rainfall. Some of the components of pest management such as host-plant resistance, biopesticides, natural enemies, and synthetic chemicals will be rendered less effective as a result of the increase in temperatures and UV radiation, and decrease in relative humidity. The rate of insect multiplication might increase with an increase in CO2 and temperature. Thus climate change might change the population dynamics of insect pests differently in different agro-ecosystem and ecological zones. Therefore, there is a need to take a concerted look at the likely effects of climate change on crop protection and devise appropriate measures to mitigate the effects of climate change on food security

On the number of kk-cycles in the assignment problem for random matrices

We continue the study of the assignment problem for a random cost matrix. We analyse the number of $k$-cycles for the solution and their dependence on the symmetry of the random matrix. We observe that for a symmetric matrix one and two-cycles are dominant in the optimal solution. In the antisymmetric case the situation is the opposite and the one and two-cycles are suppressed. We solve the model for a pure random matrix (without correlations between its entries) and give analytic arguments to explain the numerical results in the symmetric and antisymmetric case. We show that the results can be explained to great accuracy by a simple ansatz that connects the expected number of $k$-cycles to that of one and two cycles.Comment: To appear in Journal of Statistical Mechanic

Identification of sorghum genotypes with resistance to the sugarcane aphid Melanaphis sacchari under natural and artificial infestation

Sugarcane aphid, Melanaphis sacchari is an endemic pest of sorghum during postrainy season, and there is a need to develop cultivars with resistance to this pest. Evaluation of a diverse array of sorghum genotypes under natural and artificial infestation resulted in identification of seven lines (ICSB 215, ICSB 323, ICSB 724, ICSR 165, ICSV 12001, ICSV 12004 and IS 40615) with moderate levels of resistance to aphid damage. Under artificial infestation, 10 lines suffered 30 q/ha). In another experiment, ICSB 215, ICSB 695, ICSR 161, Line 61510, ICSV 12004, Parbhani Moti and IS 40618 exhibited high grain yield potential (>25 q/ha) and exhibited <50% variation in grain yield as compared to more than 80% in the susceptible check, in CK 60 B. The genotypes RSV 1211, RS 29, RSV 1338, EC 8-2, PU 10-1, IS 40617 and ICSB 695 though showed a susceptible reaction to aphid damage, but suffered relatively low loss in grain yield, suggesting that these lines have tolerance to aphid damage. Principal coordinate analysis suggested that the genotypes with aphid resistance are quite diverse and can be used to breed for aphid resistance and high grain yield potential and also in breeding for aphid resistance in sorghum with adaptation to the postrainy season

Stability of resistance to sorghum shoot fly, Atherigona soccata

Sorghum shoot fly, Atherigona soccata is one of the most important pests of dual-purpose sorghums during the postrainy season in India. Therefore, it is important to identify stable sources of resistance to develop cultivars with shoot fly resistance and adaptation to postrainy season. We evaluated 190 lines adapted to the postrainy season across five locations, of which 30 lines were identified with resistance to A. soccata. These lines were further evaluated for three seasons across five locations to identify lines with stable resistance to this pest across seasons and locations. Data were recorded on oviposition non-preference, deadheart incidence, recovery resistance, morphological traits (leaf glossiness, seedling vigor, plant height and days to 50% flowering), and grain yield. The sorghum genotypes CSV 22, ICSB 422, ICSB 425, ICSB 428, ICSB 432, ICSB 458, ICSB 463, IS 2312, IS 5480, IS 18662, Phule Chitra, RSV 1093, IS 18551, and RSV 1235 exhibited resistance to shoot fly damage across seasons, of which ICSB 425, ICSB 428, ICSB 432, IS 2312, IS 5480, and IS 18551 showed non-preference for oviposition. Six genotypes (ICSB 425, IS 2312, IS 18662, RSV 1090, RSV 1093, and IS 18551) also showed good recovery resistance following shoot fly damage. Principal coordinate analysis placed the maintainer lines (B-lines) with shoot fly resistance in two clusters with ICSB 422, ICSB 432, ICSB 435, ICSB 456 and ICSB 458 in one cluster and ICSB 425, ICSB 428 and ICSB 463 in the other; the open pollinated varieties/germplasm lines (restorers) were placed in a different group (CSV 22, IS 5480, IS 2312 and RSV 1093), suggesting the possibilities for developing hybrids with adaptation to the postrainy season. Based on regression coefficient and deadheart incidence, the genotypes IS 2312, ICSB 425, RSV 1090 and ICSB 428 were stable in expression of resistance to shoot fly across seasons and locations. The genotypes CSV 22 and RSV 1093 exhibited high grain yield potential and resistance to shoot fly damage, while Phule Yashoda, IS 2312, RSV 1235, and ICSV 574 were moderately resistant to shoot fly damage, but had high grain yield potential. These genotypes can be used in sorghum improvement for developing cultivars with shoot fly resistance, high grain yield and adaptation to postrainy season

Increasing Trends of Leptospirosis in Northern India: A Clinico-Epidemiological Study

Leptospirosis is often not suspected by physicians in patients with acute febrile illnesses reporting from supposedly “non-endemic areas,” including north India. Clinical manifestations are protean, and complications can affect most organ systems, including liver, kidneys, lungs, and the central nervous system. Timely diagnosis and specific therapy can reduce severity of illness and, in turn, mortality. In this study conducted at a tertiary care center in north India, we find how a much-neglected disease entity has emerged as a major cause of acute febrile illness in a so called “non-endemic area.” Incidence is increasing yearly. The majority of patients were from a rural background, and were farmers or farm labourers. Poor hygiene, contact with animals, rat infestation of houses, and contact with stagnant dirty water are the major determinants of disease. Apart from the usual symptoms of intermittent fever with chill and rigor, hepatosplenomegaly, renal decompensation, muscle pain and tenderness, and conjunctival suffusion, signs and symptoms indicating involvement of the respiratory and central nervous systems were also commonly observed. Severe complications resulting in mortality do occur and is especially due to late suspicion among primary level physicians, and the resulting inappropriate therapy