Role of aqueous two-phase systems in modulating the kinetics and dynamics of biological processes

Liquid-liquid phase separation (LLPS) phenomena have contributed immensely to the field of cell biophysics and cell biology in providing rational answers to the process of formation of membraneless organelles. These membraneless organelles play a vital role in understanding the origin of life in terms of cellular compartmentalisation. An increasing number of proteins and protein-nucleic acid mixtures has been shown to undergo LLPS at high concentrations forming two liquid phases - a protein-rich phase and a phase with diluted protein concentration. The tendency of LLPS to concentrate proteins comes with an added danger of aggregation, however, which is an issue in many human diseases such as amyloid formation in Alzheimer's disease or synuclein plaques in Parkinson's disease. High Hydrostatic Pressure (HHP) is a sophisticated tool to yield novel information on the free-energy and conformational landscape of biomolecules. Further, Earth being a predominantly high-pressure region makes it imperative to use this tool to understand the adaptability of piezophiles. However, the combined effect of LLPS and HHP on biological reactions and cellular processes, such as enzyme kinetics and ligand binding, has yet not been experimentally determined. A part of the thesis explores the combined effects of an aqueous two-phase system (ATPS) formed by the synthetic polymers polyethylene glycol (PEG) and dextran invoking LLPS and pressure on the enzymatic hydrolysis reaction of the substrate AAF-AMC catalysed by the proteolytic enzyme α-CT. In general, ATPS affects the enzymatic reactions in a variety of ways, such as partitioning in different or the same phases, increasing the effective concentration of solutes and thus inducing an excluded volume effect. Pressure, on the other hand, can increase the reaction rate and, alter the substrate specificity and stereoselectivity of an enzyme by choosing the product with a smaller partial volume, increases conformational flexibility. In this work it was observed that HHP did not have any marked effect on the kinetic constants in the ATPS, which was not possible to explain by simple steric crowding. Additional contributions, such as changes in water activity and non-specific weak interactions with ATPS components have to be considered to explain the results obtained. These results are important for understanding the use of LLPS and ATPS in modulating an enzymatic reaction for biotechnological use. The other part of this thesis focusses on the combined effects of pressure and ATPS on a ligand binding reaction, i.e., on the binding phenomenon between Bovine Serum Albumin (BSA) and 1-anilino-8-naphthalene (ANS) which was monitored through fluorescence spectroscopy. The results indicate that unlike buffer where the binding affinities to the three equivalent and independent binding sites of BSA could not be distinguished, the presence of ATPS gives rise to two binding modes, thus allowing to differentiate between weak and strong binding of the three sites. This result can be explained by considering soft interactions between the binding sites on BSA with the crowder molecules, such as PEG and dextran. Upon pressurization, the binding affinities of all binding sites decrease, which can be due to the unfavourable effect of pressure on hydrophobic interactions as well as a volume change due to release of water molecules and creation of void volume upon binding. These results also demonstrate that pressure dependent studies are able to reveal differences in binding sites of ligands, owing to the high accuracy by which volume changes can be determined

Gandhi and Bengal Politics 1920 -1940

Mohandas Karamchand Gandhi entered nationalist politics in 1920 and changed the character of the national movement completely Before 1920 Bengal politics was mainly dominated by the activities of the revolutionaries and the politics within Congress Anushilan Samity and Yugantar were the two main revolutionary groups in Bengal at the beginning of twentieth century Their main intention was to liberate their motherland through violent struggle The Congress leaders as well as the revolutionaries of Bengal were not at all ready to accept Gandhi and his doctrine of nonviolence Gandhi too had no sympathy for the revolutionaries as their method was against his principle of non-violence C R Das and Subhas Chandra Bose of Bengal Congress gave stiff opposition to Gandhi Eventually the death of C R Das and the imprisonment of Bose at Mandalay prison Burma saw the emergence of Gandhiites like J M Sengupta through whom gradually the control of Bengal Congress went into the hands of Gandhi The final showdown between Gandhi and Bose came in 1939 when Bose was compelled to resign as Congress President at Tripuri Disunity within the Left wingers non-cooperation from the Congress leaders forced Bose to leave the country to liberate his motherland with foreign hel

Provision of water to the poor in Africa : experience with water standposts and the informal water sector

Standpipes that dispense water from utilities are the most common alternatives to piped water connections for poor customers in the cities of Sub-Saharan Africa. Fifty-five percent of the unconnected urban population relies on standpipes as their first water source. Other informal water providers include household resellers and a variety of water tankers and vendors, which are the first water source of 1 percent and 3 percent of the urban population, respectively. In the cities studied, the percentage of unconnected households ranges from 12 percent to 86 percent of the population. The percentage of unconnected people covered by standpipes is substantially higher for countries with higher rates of household connection, while the percentage of unconnected people covered by water tankers or water vendors is higher for countries with lower rates of household connection. Water prices in the informal market are much higher than for households with private connections or yard taps. Although standpipes are heavily subsidized by utilities, the prices charged by standpipe operators are closely related to the informal water reseller price. Standpipe management models also affect the informal price of water. For example, the shift from utilities management to delegated management models without complementary regulation or consumer information has often led to declines in service levels and increased prices. Standpipes are not the only or even the most efficient solution in peri-urban areas. Programs that promote private household connections and arrangements that improve pricing and services in the household resale market should also be considered by policy makers.Town Water Supply and Sanitation,Urban Water Supply and Sanitation,Water Supply and Sanitation Governance and Institutions,Water and Industry,Water Conservation

Pollution Control Instruments in the Presence of an Informal Sector

We examines the challenges faced by the regulator in managing pollution when there is a linkage between a formal and an informal industrial sector across the stages of production. The formal sector is more productive than the informal sector and the latter saves cost by evading pollution regulation due to incomplete monitoring. This creates a natural tendency for the more polluting processes to be concentrated in the informal sector. We show the unintended effects of the standard Pigouvian tax (emission fee), which might lead to further deterioration by encouraging the shift of stages in favour of the informal sector. Instead, we propose a second-best hybrid instrument, comprised of a tax on polluting input and a subsidy on proper disposal of residual waste.Emissions tax, informal sector, pollution control, vertical production.

Measuring trends in access to modern infrastructure in Sub-Saharan Africa: Results from Demographic and Health Surveys

This short dissemination note provides a synthesis of key results from a recent study on access to infrastructure services in Africa. Using Demographic and Health Surveys from 22 countries that have conducted at least two such surveys between 1990 and 2005, we provide comparable estimates over time of access to electricity, piped water, flush toilets, and landline telephones. In addition to national, urban, and rural trends in access, we also provide a distributional analysis of how access rates have evolved between 1990 and 2005.Electricity; piped water; flush toilets; landline phones; access rates; Africa

Trends in household coverage of modern infrastructure services in Africa

Household surveys have long been used to estimate poverty and inequality trends, as well as trends in education and health indicators, but they have not been used to the same extent to assess trends in the access to or coverage of modern infrastructure services. In this paper, we use Demographic and Health Surveys from a larger sample of sub-Saharan African countries in order to collect comparable information across countries on coverage of piped water, flush toilets, electricity, and landline telephones over time. The results suggest that coverage rates for electricity, flush toilets have improved slightly over the last decade. Coverage of piped water has declined, at the same time as coverage of landline (as well as cellular) telephone has increased rapidly. The decline has been primarily in the urban areas while the infrastructure coverage has either increased or remained stable in rural Africa. For all four services, among the poorest households coverage remains virtually inexistent. If business as usual continues, it would take a very long time to reach universal or widely shared coverage even in countries where coverage has improved. These results point to the need to increase efforts by governments and international community to progressively increase access to modern infrastructure services in Africa.Town Water Supply and Sanitation,Population Policies,Urban Water Supply and Sanitation,Urban Slums Upgrading,Urban Services to the Poor

Is low coverage of modern infrastructure services in African cities due to lack of demand or lack of supply ?

A majority of sub-Saharan Africa’s population is not connected to electricity and piped water networks, and even in urban areas coverage is low. Lack of network coverage may be due to demand or supply-side factors. Some households may live in areas where access to piped water and electricity is feasible, but may not be able to pay for those services. Other households may be able to afford the services, but may live too far from the electric line or water pipe to have a choice to be connected to it. Given that the policy options for dealing with demand as opposed to supply-side issues are fairly different, it is important to try to measure the contributions of both types of factors in preventing better coverage of infrastructure services in the population. This paper shows how this can be done empirically using household survey data and provides results on the magnitude of both types of factors in explaining the coverage deficit of piped water and electricity services in urban areas for a large sample of African countries.Currencies and Exchange Rates,,Economic Theory&Research,Geographical Information Systems,Markets and Market Access

Cost recovery, equity, and efficiency in water tariffs : evidence from African utilities

Water and sanitation utilities in Africa operate in a high-cost environment. They also have a mandate to at least partially recover their costs of operations and maintenance (O&M). As a result, water tariffs are higher than in other regions of the world. The increasing block tariff (IBT) is the most common tariff structure in Africa. Most African utilities are able to achieve O&M cost recovery at the highest block tariffs, but not at the first-block tariffs, which are designed to provide affordable water to low-volume consumers, who are often poor. Atthe same time, few utilities can recover even a small part of their capital costs, even in the highest tariff blocks. Unfortunately, the equity objectives of the IBT structure are not met in many countries. The subsidy to the lowest tariff-block does not benefit the poor exclusively, and the minimum consumption charge is often burdensome for the poorest customers. Many poor households cannot even afford a connection to the piped water network. This can be a significant barrier to expansion for utilities. Therefore, many countries have begun to subsidize household connections. For many households, standposts managed by utilities, donors, or private operators have emerged as an alternative to piped water. Those managed by utilities or that supply utility water are expected to use the formal utility tariffs, which are kept low to make water affordable for low-income households. The price for water that is resold through informal channels, however, is much more expensive than piped water.Town Water Supply and Sanitation,Infrastructure Economics,Urban Water Supply and Sanitation,Water Supply and Systems,Energy Production and Transportation

The transformation of domesticity as an ideology: Calcutta, 1880-1947.

This study of the ideology of domesticity among the Bengali Hindu middle-class of Calcutta between 1880 and 1947 problematises the relation between anti-colonial nationalism and domesticity by contextualising it in a social history perspective. The thesis argues that the nationalist domestic ideology of the class was not a mere counter-discursive derivative of colonial power/knowledge. Its development was a dialectical process; in it the agency of the live experience of domesticity, as the primary level of this group's reproduction of its class identity, material anxieties, status, and gender ideology, interacted with nationalist counter- discursive abstractions. This dialectic, the thesis argues, made the domestic ideology of the colonial middle class a transforming entity. Indeed, because of this dynamism, early nationalist essentialisations regarding domesticity disintegrated during the late colonial period (1920-1947). Anti-colonial nationalism, crystallised by the late 19th century, spiritualised domesticity as a part of an essential 'inner-domain' that was upheld in order to culturally exteriorise the 'materialist' colonial sphere. But this interiorisation and spiritualisation was not a one-way process in which lived domesticity was passively inscribed from above by a preconceived nation. While nationalist abstractions sought to 'recast' the home, the lived domesticity of the class, in its turn, inscribed its agency on nationalism by acting as the fundamental lived unit which was paradigmatically extended to imagine and order the middle- class-led nation. Given this dialectic, there was the possibility of the nationalist idealisation of the home changing if the lived situation of the class became substantially transformed. Contesting the ahistoricity of recent studies on nationalist domesticity, this thesis argues that such a transformation actually did come about in the period after the First World War. Under its impact, the dominant perception of domesticity changed, creating a discursive transformation that sidelined the ideology formulated in the late 19th-century. The spiritualist rhetoric disintegrated. So did the binary division that had projected the colonial sphere as the only 'outside' as against a harmonious 'inside' in which domesticity, community and the nation existed in an idealised continuum. Thus, a domestic ideology, that anti-colonial consciousness had deeply integrated with the class's self-justification and claim to 'natural leadership', disintegrated largely under pressure. Consequently, it left behind the deep imprint of some of its expectations in the middle-class consciousness. The disintegration thus generated a sense of disorientation rather than a liberating feeling for the middle-class majority on the eve of political independence