A REVIEW ON A FLASH CHROMATOGRAPHY

ABSTRACT Flash chromatography is rapid form of preparative column chromatography-preparative liquid chromatography based upon an air pressure driven hybrid of medium and short column chromatography optimized for rapid separation of organic compounds. As technology has evolved available guidelines for normal-phase flash chromatography have become less relevant. Years of experience performing chromatography with disposable columns have been condensed into simple guidelines useful for translating TLC results into either isocratic-or gradient-flash chromatography. The described studies should provide researchers with a means of selecting adequate columns and guidelines to reduce the waste of solvents, silica, time, and money. Modern flash chromatography systems are sold as pre-packed plastic cartridges and the solvent is pumped through the cartridge. These systems may also be linked with detectors and fraction collectors providing automation. The introduction of gradient pumps has resulted in quicker separations and less solvent usage

β2-adrenoceptor-induced modulation of transglutaminase 2 transamidase activity in cardiomyoblasts

Tissue transglutaminase 2 (TG2) is modulated by protein kinase A (PKA) mediated phosphorylation: however, the precise mechanism(s) of its modulation by G-protein coupled receptors coupled to PKA activation are not fully understood. In the current study we investigated the potential regulation of TG2 activity by the β2-adrenoceptor in rat H9c2 cardiomyoblasts. Transglutaminase transamidation activity was assessed using amine-incorporating and protein cross-linking assays. TG2 phosphorylation was determined via immunoprecipitation and Western blotting. The long acting β2-adrenoceptor agonist formoterol induced time- and concentration-dependent increases in TG2 transamidation. Increases in TG2 activity were reduced by the TG2 inhibitors Z-DON (Benzyloxycarbonyl-(6-Diazo-5-oxonorleucinyl)-L-valinyl-L-prolinyl-L-leucinmethylester) and R283 (1,3,dimethyl-2[2-oxo-propyl]thio)imidazole chloride). Responses to formoterol were blocked by pharmacological inhibition of PKA, extracellular signal-regulated kinase 1 and 2 (ERK1/2), or phosphatidylinositol 3-kinase (PI-3K) signalling. Furthermore, the removal of extracellular Ca2+ also attenuated formoterol-induced TG2 activation. Fluorescence microscopy demonstrated TG2-induced biotin-X-cadaverine incorporation into proteins. Formoterol increased the levels of TG2-associated phosphoserine and phosphothreonine, which were blocked by inhibition of PKA, ERK1/2 or PI-3K signalling. Subsequent proteomic analysis identified known (e.g. lactate dehydrogenase A chain) and novel (e.g. Protein S100-A6) protein substrates for TG2. Taken together, the data obtained suggest that β2-adrenoceptor-induced modulation of TG2 represents a novel paradigm in β2-adrenoceptor cell signalling, expanding the repertoire of cellular functions responsive to catecholamine stimulation

β2-adrenoceptor-induced modulation of transglutaminase 2 transamidase activity in cardiomyoblasts

Tissue transglutaminase 2 (TG2) is modulated by protein kinase A (PKA) mediated phosphorylation: however, the precise mechanism(s) of its modulation by G-protein coupled receptors coupled to PKA activation are not fully understood. In the current study we investigated the potential regulation of TG2 activity by the β2-adrenoceptor in rat H9c2 cardiomyoblasts. Transglutaminase transamidation activity was assessed using amine-incorporating and protein cross-linking assays. TG2 phosphorylation was determined via immunoprecipitation and Western blotting. The long acting β2-adrenoceptor agonist formoterol induced time- and concentration-dependent increases in TG2 transamidation. Increases in TG2 activity were reduced by the TG2 inhibitors Z-DON (Benzyloxycarbonyl-(6-Diazo-5-oxonorleucinyl)-L-valinyl-L-prolinyl-L-leucinmethylester) and R283 (1,3,dimethyl-2[2-oxo-propyl]thio)imidazole chloride). Responses to formoterol were blocked by pharmacological inhibition of PKA, extracellular signal-regulated kinase 1 and 2 (ERK1/2), or phosphatidylinositol 3-kinase (PI-3K) signalling. Furthermore, the removal of extracellular Ca2+ also attenuated formoterol-induced TG2 activation. Fluorescence microscopy demonstrated TG2-induced biotin-X-cadaverine incorporation into proteins. Formoterol increased the levels of TG2-associated phosphoserine and phosphothreonine, which were blocked by inhibition of PKA, ERK1/2 or PI-3K signalling. Subsequent proteomic analysis identified known (e.g. lactate dehydrogenase A chain) and novel (e.g. Protein S100-A6) protein substrates for TG2. Taken together, the data obtained suggest that β2-adrenoceptor-induced modulation of TG2 represents a novel paradigm in β2-adrenoceptor cell signalling, expanding the repertoire of cellular functions responsive to catecholamine stimulation

Facets of diazotrophy in the oxygen minimum zone waters off Peru

Nitrogen fixation, the biological reduction of dinitrogen gas (N2) to ammonium (NH4+), is quantitatively the most important external source of new nitrogen (N) to the open ocean. Classically, the ecological niche of oceanic N2 fixers (diazotrophs) is ascribed to tropical oligotrophic surface waters, often depleted in fixed N, with a diazotrophic community dominated by cyanobacteria. Although this applies for large areas of the ocean, biogeochemical models and phylogenetic studies suggest that the oceanic diazotrophic niche may be much broader than previously considered, resulting in major implications for the global N-budget. Here, we report on the composition, distribution and abundance of nifH, the functional gene marker for N2 fixation. Our results show the presence of eight clades of diazotrophs in the oxygen minimum zone (OMZ) off Peru. Although proteobacterial clades dominated overall, two clusters affiliated to spirochaeta and archaea were identified. N2 fixation was detected within OMZ waters and was stimulated by the addition of organic carbon sources supporting the view that non-phototrophic diazotrophs were actively fixing dinitrogen. The observed co-occurrence of key functional genes for N2 fixation, nitrification, anammox and denitrification suggests that a close spatial coupling of N-input and N-loss processes exists in the OMZ off Peru. The wide distribution of diazotrophs throughout the water column adds to the emerging view that the habitat of marine diazotrophs can be extended to low oxygen/high nitrate areas. Furthermore, our statistical analysis suggests that NO2− and PO43− are the major factors affecting diazotrophic distribution throughout the OMZ. In view of the predicted increase in ocean deoxygenation resulting from global warming, our findings indicate that the importance of OMZs as niches for N2 fixation may increase in the futu

Trends in Fragmentation of Production: A Comparative Study of Asia and Latin America

AbstractDuring the last decade dramatic changes have taken place in the direction and pattern of trade of the emerging economies. Notable amongst them is the thriving trade in rsquo;fragmentation’ also called trade in Parts, Components and Accessories (PCA) wherein the production process is split into two or more steps. This growth in fragmentation trade involves relocating production stages to low cost countries where labour is abundant. In this paper, we examine and compare the trends in PCA exports of 12 emerging economies (9 from Asia and 3 from Latin America) for a period from 1994 to 2009. Empirical evidence suggests that considerable churning has taken place in Asia in exports of PCA as compared to countries in Latin America. For instance, Singapore occupied a leading position in 1994, but vacated it in 2002 which was occupied by Philippines. Further, we examine the share of Electronics and Automotive parts in total PCA exports and find that exports of Electronic parts account for a dominant share of PCA exports in Asia, but that of Automotive parts are a small fraction of the total PCA exports. But on the other hand, although exports of PCA are a small percentage of total exports in the Latin American countries, the production networks in automotive parts are more advanced compared to Asia. We use the Lafay index of specialization to study the changing comparative advantage of countries over time. The Logistic Performance Index and the Foreign Direct Investment inflows can to some extent explain the booming PCA trade. It is against this backdrop that we argue that there is need for a paradigm shift in the trade policies formulated and implemented by the governments. Policies must ensure productivity gains, up gradation of the manufacturing sector, expansion of domestic demand, participation of all segments of the population in income generation and so on

Economics of healthy aging in India: A multidimensional perspective

Aging is the foremost challenge in recent times, given the demographic shift in populations across the world. It implies the costs of healthcare burden and involves economic and social security challenges through shortage of labor supply, consumption-saving paradox, increase in expenditure on healthcare, and most importantly, social capital among the developing countries. Furthermore, there is a likely challenge of old age security in terms of income and expenditure due to increasing healthcare costs and low earning incentives at older ages. India currently has the second largest population globally, with >9% of its population accounting for aging. Based on the multidimensional aging index (AI) using the latest longitudinal survey data of older adults in India, we examined the possible challenges of the economics of aging in India while examining the economic health and social outcomes of the elderly. Our results found that the elderly in India are highly exposed to negative impacts due to vulnerability in socio-economic and health spheres of life. Low labor force participation, lack of skills, and low literacy are the prevalent challenges faced by the elderly Indian population, particularly women. Similarly, the fiscal challenges include increased income tax and insurance coverage for the elderly, while health challenges imply a greater proportion of the disabled and multi-morbid, leading to more burden on the health and welfare system of India. Thus, given the possible short- and long-term effects of aging on the path of economic growth in India, policy incentives are required to minimize the impact and avert the burden of population aging in the country

Local DNA microviscosity converts ruthenium polypyridyl complexes to ultrasensitive photosensitizers

In this manuscript, we have reported how DNA binding of ruthenium polypyridyl complexes (RPCs) make them more efficient photosensitizer. The DNA binding of RPCs results in a significant enhancement of their emission intensity and excited-state lifetime. As a result, upon visible-light irradiation, these complexes generate reactive singlet oxygen, which causes selective DNA damage and kills cancer cells. This investigation also demonstrates the effect of light-driven RPCs on bacterial growth arrest through DNA nicking and differential localization in cancer and non-cancer cells. The local DNA microviscosity suppresses the non-radiative pathways which causes a large enhancement in the emission intensity and the excited state lifetime. The visible-light-triggered singlet-oxygen efficiently produces nick in DNA and inhibits bacterial growth. RPCs also localize inside the cancer cell nucleus and in the vicinity of the nuclear membrane of non-cancerous cells, confirmed by live-cell confocal microscopy. The results provide a facile platform for the novel antibiotic intended discovery combined with cancer therapy