Membrane Organization of the Serotonin<Subscript><Emphasis Type="Bold">1A</Emphasis></Subscript> Receptor Monitored by a Detergent-Free Approach

1. Insolubility of membrane constituents in nonionic detergents such as Triton X-100 has been a widely used biochemical criterion to indicate their localization in membrane domains. However, concerns on the possibility of membrane perturbation in the presence of detergents have led to the development of detergent-free approaches. 2. We have explored the organization of the serotonin_1A receptor, an important G-protein coupled receptor, from bovine hippocampus and CHO cells using a detergent-free approach in order to address the points of agreement with our previous results using Triton X-100. 3. A significant fraction of the serotonin_1A receptor has been found to be localized in a heavy density fraction obtained using a detergent-free approach to isolate membrane domains. In addition, we have characterized the membrane fractions isolated in terms of their lipid composition and membrane physical properties. 4. The results obtained on the membrane localization of the serotonin_1A receptor from the present experiments using a detergent-free approach correlate well with our earlier findings obtained using a detergent-based method (Kalipatnapu, S., and Chattopadhyay, A., FEBS Lett. 576:455–460, 2004). These results provide important information on the membrane organization of the hippocampal serotonin_1A receptor and are relevant in view of the concerns on the use of detergent in determination of membrane organization of constituent proteins and lipids.     

“Nothing Special,Everything Is Maamuli”: Socio-Cultural and Family Practices Influencing the Perinatal Period in Urban India

Background

Globally, India contributes the largest share in sheer numbers to the burden of maternal and infant under-nutrition, morbidity and mortality. A major gap in our knowledge is how socio-cultural practices and beliefs influence the perinatal period and thus perinatal outcomes, particularly in the rapidly growing urban setting.

Methods and Findings

Using data from a qualitative study in urban south India, including in-depth interviews with 36 women who had recently been through childbirth as well as observations of family life and clinic encounters, we explored the territory of familial, cultural and traditional practices and beliefs influencing women and their families through pregnancy, childbirth and infancy. We found that while there were some similarities in cultural practices to those described before in studies from low resource village settings, there are changing practices and ideas. Fertility concerns dominate women’s experience of married life; notions of gender preference and ideal family size are changing rapidly in response to the urban context; however inter-generational family pressures are still considerable. While a rich repertoire of cultural practices persists throughout the perinatal continuum, their existence is normalised and even underplayed. In terms of diet and nutrition, traditional messages including notions of ‘hot’ and ‘cold’ foods, are stronger than health messages; however breastfeeding is the cultural norm and the practice of delayed breastfeeding appears to be disappearing in this urban setting. Marriage, pregnancy and childbirth are so much part of the norm for women, that there is little expectation of individual choice in any of these major life events.

Conclusions

A greater understanding is needed of the dynamic factors shaping the perinatal period in urban India, including an acknowledgment of the health promoting as well as potentially harmful cultural practices and the critical role of the family. This will help plan culturally appropriate integrated perinatal health care.     

RAPD Analysis of Genetic Diversity in Indian Tetraploid and Diploid Cotton (Gossypium spp)

Random Amplified Polymorphic DNA (RAPD) analysis was used to evaluate genetic diversity among commercial Indian cotton varieties. Fifteen varieties belonging to Gossypium hirsutum L and seven to G. arboreum L were analyzed with 50 random decamer primers using the polymerase chain reaction (PCR). Twenty six of the primers detected polymorphism in all 22 cotton varieties. A total of 371 bands were amplified, 87% of which were polymorphic. Cluster analysis by the unweighted pair group method of arithmetic means (UPGMA) showed that diploids and tetraploids can be divided in two groups at a similarity of 30%. Diploid variety C402W showed the least similarity to all the others in the group. Among tetraploids, closely related varieties Pusa 8-6, 4515 and RS 875 were distinctly different from the rest. The analysis revealed that the intervarietal genetic relationships of several varieties is related to their pedigree. The results also revealed that tetraploids show a much narrower genetic base (similarity range of 65–95%) than the diploids (similarity range 54–88%). The results obtained can be used for the selection of parents to generate a mapping population and begin a breeding programme.     

Effects of mutations at thestambh A locus ofDrosophila melanogaster

We report novel findings on the cytogenetic location, functional complexity and maternal and germline roles of thestambh A locus ofDrosophila melanogaster. stmA is localized to polytene bands 44D1.2 on 2R.stmA mutations are of two types: temperature-sensitive (ts) adult and larval paralytic or unconditional embryonic or larval lethal. Twelve alleles reported in this study fall into two intragenic complementing groups suggesting thatstmA is a complex locus with more than one functional domain. Some unconditional embryonic lethal alleles show a ‘neurogenic’ phenotype of cuticle loss accompanied by neural hypertrophy. It is shown that embryos of ts paralytic alleles also show mild neural hypertrophy at permissive temperatures while short exposure to heat induces severe cuticle loss in these embryos.stmA exerts a maternal influence over heat-induced cuticle loss. Unconditional embryonic lethal alleles ofstmA are also germline lethal.     

Heavy metal-induced accumulation of free proline in a metal-tolerant and a nontolerant ecotype of Silene vulgaris

Accumulation of free proline in response to Cu, Cd and Zn was studied in nontolerant and metal-tolerant Silene vulgaris (Moench) Garcke. In the nontolerant ecotype these metals induced a massive accumulation of proline, especially in the leaves. When compared at equimolar concentrations in the nutrient solution, Cu was the most effective inducer, followed by Cd and Zn, respectively. However, when compared at equal toxic strength, as estimated from the degree of root growth inhibition, proline accumulation decreased in the order Cd > Zn > Cu. The threshold exposure levels for proline accumulation coincided with the highest no-effect-concentrations for root growth. In the metal-tolerant ecotype the constitutive proline concentration in the leaves was 5 to 6 times higher than in the nontolerant ecotype. Exposure to Cu and Zn, however, was without any effect on the leaf proline concentration, even at exposure levels that caused a 50% root growth inhibition. Only Cd, when present at concentrations above the highest no-effect-concentration for root growth, induced a further increase of the leaf proline content. Reducing transpiration by placing the plants under a transparent polyethylene cover almost completely inhibited proline accumulation, even at metal accumulation rates in the leaves that caused a 10-fold increase of the proline level in leaves of uncovered plants. The results demonstrate that metal-induced proline accumulation depends on the development of a metal-induced water deficit in the leaves. Differential metal-induced proline accumulation in distinctly metal-tolerant ecotypes is a consequence, rather than a cause of differential metal tolerance.     

Vacuolar compartmentalization as indispensable component of heavy metal detoxification in plants

Plant cells orchestrate an array of molecular mechanisms for maintaining plasmatic concentrations of essential heavy metal (HM) ions, for example, iron, zinc and copper, within the optimal functional range. In parallel, concentrations of non‐essential HMs and metalloids, for example, cadmium, mercury and arsenic, should be kept below their toxicity threshold levels. Vacuolar compartmentalization is central to HM homeostasis. It depends on two vacuolar pumps (V‐ATPase and V‐PPase) and a set of tonoplast transporters, which are directly driven by proton motive force, and primary ATP‐dependent pumps. While HM non‐hyperaccumulator plants largely sequester toxic HMs in root vacuoles, HM hyperaccumulators usually sequester them in leaf cell vacuoles following efficient long‐distance translocation. The distinct strategies evolved as a consequence of organ‐specific differences particularly in vacuolar transporters and in addition to distinct features in long‐distance transport. Recent molecular and functional characterization of tonoplast HM transporters has advanced our understanding of their contribution to HM homeostasis, tolerance and hyperaccumulation. Another important part of the dynamic vacuolar sequestration syndrome involves enhanced vacuolation. It involves vesicular trafficking in HM detoxification. The present review provides an updated account of molecular aspects that contribute to the vacuolar compartmentalization of HMs.     

Protein and enzyme levels during development in a high lysine barley mutant

Dry weight, protein, total free amino acids, levels of nitrogen assimilation, enzymes GDH, GOT and glutamate synthase, hydrolytic enzymes protease and amylase, peroxidase and nitrate reductase have been studied in high lysine barley mutant Notch-2 and its parents, NP 113 grains, during development. Dry weight and protein per grain was higher in NP 113 throughout development. The decrease in protein in Notch-2 mutant is neither due to limitation of amino acids nor to any of the key nitrogen assimilating enzymes as evident from the higher level of free amino acids, nitrate reductase and comparable levels of GDH, GOT and glutamate synthase in it as compared to its parent NP 113. During later stages of development, protease level between NP 113 and Notch-2 was nearly the same. Notch-2 had a lower level of amylase activity per grain. Peroxidase activity was higher in Notch-2 than NP 113 at and after the 17 day stage.