The Relation Between Ion Absorption and Protein Synthesis in Beet Disks

Disks of red beet storage tissue were incubated under asepticconditions permitting the development of various metabolic processescommonly associated with aged disks, and the effects of chloramphenicoland puromycin on protein synthesis, on the development of invertaseactivity and ion absorption capacity, and on ion absorptionper se were determined. Low concentrations of chloramphenicoland puromycin inhibit the development of ion absorption capacitybut stimulate invertase development and protein synthesis, whilehigher concentrations inhibit all three processes. In contrastion absorption itself is unaffected by puromycin, but is sensitiveto quite low concentrations of chloramphenicol The D-threo andL-threo isomers of chloramphenicol have sharply contrasted effectson the development, as distinct from the utilization, of ionabsorption capacity. The D isomer inhibits the development ofion absorption capacity more effectively than the L isomer whichin turn inhibits absorption more effectively than the D isomer. A reappraisal is made of the hypothesis that ion absorptionis directly linked with protein turnover and to account forthe results a model is proposed in which D-threo-chloramphenicolis active both as an uncoupler of oxidative phosphoryalationand as an inhibitor of protein synthesis, while L-threo-chloramphenicolacts only in the former capacity and puromycin only in the latter.It is concluded that the inhibition of ion uptake by chloramphenicolcannot be attributed to a contemporaneous effect on proteinsynthesis. However, the results are consistent with the involvementof ATPase proteins in ion uptake.     

An Acrylamide Gel Electrophoretic Study of the Seed Proteins of Brassica and Sinapis Species, with Special Reference to their Taxonomic Value

The albumin and globulin fractions of the seeds of a wide rangeof Brassica and Sinapis species have been investigated by acrylamidegel electrophoresis. The results of this investigation havebeen presented in the form of a three-dimensional model andcorrelation between this model, the distribution of the proteins,and the established taxonomy has been indicated.     

Independence Training from a Cross-Cultural Perspective

Studies relating age of independence training with achievement motivation and achievement have resulted in contradictory findings. The responses of fifty-two Chinese mothers in Hawaii to the independence training questionnaire were analyzed in conjunction with ethnographic data on child rearing practices. The lack of significant relationships between the index of independence training and measures of boys' achievement motivation and achievement behaviors was explained by the failure of the questionnaire to tap the mother's underlying motives for stating particular ages. The Chinese data revealed that cultural factors, such as values, strongly affect the mothers' responses.     

Juvenile salmonid populations in a temperate river system track synoptic trends in climate

Widespread declines among Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) over recent decades have been linked to pollution, exploitation and catchment modification, but climate change is increasingly implicated. We used long‐term, geographically extensive data from the Welsh River Wye, formerly a major salmon river, to examine whether climatically mediated effects on juveniles (>0+) might contribute to population change. Populations of Atlantic salmon and brown trout fell across the Wye catchment, respectively, by 50% and 67% between 1985 and 2004, but could not be explained by pollution because water quality improved during this time. Stream temperatures, estimated from calibrations against weekly air temperature at eight sites, increased by 0.5–0.7 °C in summer and 0.7–1.0 °C in winter, with larger tributaries warming more than shaded headwaters. Rates of winter warming were slightly greater after accounting for the effect of the North Atlantic Oscillation (1.1–1.4 °C). However, warming through time was smaller than measured variations among tributaries, and alone was insufficient to explain variations in salmonid density. Instead, population variations were best explained in multilevel mixed models by a synoptic variate representing a trend towards hotter, drier summers, implying interactions between climate warming, varying discharge and fluctuations in both brown trout and salmon. Taken alongside recent data showing effects of warming on survival at sea, these data suggest that Atlantic salmon might be jeopardized by future climatic effects in both their marine and freshwater stages. Effects on nondiadromous brown trout also imply climatically mediated processes in freshwaters or their catchments. Climate projections for the United Kingdom suggest that altered summer flow and increasing summer temperatures could exacerbate losses further in these species, and we advocate management actions that combine reduced abstraction with enhanced riparian shading.     

ACCESS TO TREATMENT IN HIV PREVENTION TRIALS: PERSPECTIVES FROM A SOUTH AFRICAN COMMUNITY

Access to treatment, in HIV vaccine trials (HVTs), remains ethically controversial. In most prevention trials, including in South Africa, participants who seroconvert are referred to publicly funded programmes for treatment. This strategy is problematic when there is inadequate and uneven access to public sector antiretroviral therapy (ART) and support resources. The responsibilities, if any, of researchers, sponsors and public health authorities involved in HVTs has been hotly debated among academics, scholars, representatives of international organizations and sponsors. However, there is little published on community perceptions. Recent guidance asserts that communities should make inputs into treatment and care decisions. This qualitative study explored a South African community's perceptions of who should provide what to HVT participants as well as how and why this should be done. Twenty‐nine adults working at or attending five primary health care clinics in two rural areas in KwaZulu‐Natal participated in in‐depth interviews. Respondents expressed that researchers should ‘help participants to access’ treatment and care ‘because they are in a position to do so’ and ‘are in a relationship with’ trial participants. Respondents suggested that researchers could help by ‘facilitating referral’ until such time that participants can access care and treatment on their own. We highlight a series of implications for researchers in HVTs, including their need to be aware of prospective participants' considerable trust in and respect for researchers, the responsibility that this places on them, and the need for clear communication with communities so as not to erode community trust.     

Arsenic release and attenuation in low organic carbon aquifer sediments from West Bengal

High arsenic concentrations in groundwater are causing a humanitarian disaster in Southeast Asia. It is generally accepted that microbial activities play a critical role in the mobilization of arsenic from the sediments, with metal‐reducing bacteria stimulated by organic carbon implicated. However, the detailed mechanisms underpinning these processes remain poorly understood. Of particular importance is the nature of the organic carbon driving the reduction of sorbed As(V) to the more mobile As(III), and the interplay between iron and sulphide minerals that can potentially immobilize both oxidation states of arsenic. Using a multidisciplinary approach, we identified the critical factors leading to arsenic release from West Bengal sediments. The results show that a cascade of redox processes was supported in the absence of high loadings of labile organic matter. Arsenic release was associated with As(V) and Fe(III) reduction, while the removal of arsenic was concomitant with sulphate reduction. The microbial populations potentially catalysing arsenic and sulphate reduction were identified by targeting the genes arrA and dsrB, and the total bacterial and archaeal communities by 16S rRNA gene analysis. Results suggest that very low concentrations of organic matter are able to support microbial arsenic mobilization via metal reduction, and subsequent arsenic mitigation through sulphate reduction. It may therefore be possible to enhance sulphate reduction through subtle manipulations to the carbon loading in such aquifers, to minimize the concentrations of arsenic in groundwaters.