TRK1 encodes a plasma membrane protein required for high-affinity potassium transport in Saccharomyces cerevisiae.

We identified a 180-kilodalton plasma membrane protein in Saccharomyces cerevisiae required for high-affinity transport (uptake) of potassium. The gene that encodes this putative potassium transporter (TRK1) was cloned by its ability to relieve the potassium transport defect in trk1 cells. TRK1 encodes a protein 1,235 amino acids long that contains 12 potential membrane-spanning domains. Our results demonstrate the physical and functional independence of the yeast potassium and proton transport systems. TRK1 is nonessential in S. cerevisiae and maps to a locus unlinked to PMA1, the gene that encodes the plasma membrane ATPase. Haploid cells that contain a null allele of TRK1 (trk1 delta) rely on a low-affinity transporter for potassium uptake and, under certain conditions, exhibit energy-dependent loss of potassium, directly exposing the activity of a transporter responsible for the efflux of this ion.     

Cytogenetic effects of benzene: dosimetric studies on rats exposed to benzene vapour

Rats were exposed to benzene vapour at nominal concentrations in air of 1, 10, 100 and 1000 ppm acutely for 6 h. Bone marrow cells from each animal were examined for chromosomal abnormalities 24 h after the end of the exposure period. This analysis was carried out on 250 metaphases per animal where possible and showed a significant increase in the percentage of cells with chromosomal abnormalities, excluding gaps, in the groups of animals exposed to 100 and 1000 ppm benzene. In the 10-ppm and 1-ppm exposure groups there were elevated levels of cells with abnormalities which showed evidence of being dose-related, although they were not statistically significant.     

Outcome of elective prostatectomy.

OBJECTIVES--To determine the symptomatic and urodynamic outcome of elective prostatectomy and to establish whether the outcome is influenced or can be predicted by preoperative urodynamic measurements. DESIGN--Prospective non-randomised study with follow up at a mean of 11 months after operation. Most men were assessed jointly by a urologist and a general practitioner. SETTING--Department of urology in a teaching hospital serving a large district population. PATIENTS--253 Men listed for elective prostatectomy because of symptoms and low urinary flow rates (less than 15 ml/s) and excluding those already on a waiting list or with acute urinary retention, clinically apparent prostatic cancer, and neurological or cerebrovascular disease; 217 (86%) were followed up. INTERVENTION--Elective prostatectomy. MAIN OUTCOME MEASURE--Classification on the basis of relief of symptoms assessed by patients and urologist and general practitioner and of symptom scores obtained by questionnaire. RESULTS--Of the 217 men followed up, 171 (79%) had a satisfactory subjective review and 155 (72%) had a satisfactory review and also low symptom scores. An unsatisfactory outcome was associated with preoperative symptoms of urge incontinence, small prostatic size and resected weight, low voiding pressures, and low urethral resistance. Preoperative maximum urinary flow rates did not predict outcome. Men with poor outcome could be classified into two groups: those with irritative symptoms who were more likely before operation to have had urge incontinence and detrusor instability and men with symptoms of poor urinary flow who were more likely before operation to have had a small prostate, low voiding pressures, and low urethral resistance. In patients in the second group flow rates or voiding pressures improved little after operation. Men with stable detrusors and either low urethral resistance or low voiding pressures were less likely to do well after prostatectomy, but despite these associations preoperative urodynamic measurements were unable to predict outcome accurately. CONCLUSIONS--Prostatectomy was satisfactory in relieving symptoms and improving urodynamic measurements in most men, but even in those with classic symptoms and low urinary flow rates a substantial minority experienced little improvement afterwards and urodynamic measurements did not accurately predict outcome in individual patients.     

Symmetric cell division in pseudohyphae of the yeast Saccharomyces cerevisiae.

Laboratory strains of Saccharomyces cerevisiae are dimorphic; in response to nitrogen starvation they switch from a yeast form (YF) to a filamentous pseudohyphal (PH) form. Time-lapse video microscopy of dividing cells reveals that YF and PH cells differ in their cell cycles and budding polarity. The YF cell cycle is controlled at the G1/S transition by the cell-size checkpoint Start. YF cells divide asymmetrically, producing small daughters from full-sized mothers. As a result, mothers and daughters bud asynchronously. Mothers bud immediately but daughters grow in G1 until they achieve a critical cell size. By contrast, PH cells divide symmetrically, restricting mitosis until the bud grows to the size of the mother. Thus, mother and daughter bud synchronously in the next cycle, without a G1 delay before Start. YF and PH cells also exhibit distinct bud-site selection patterns. YF cells are bipolar, producing their second and subsequent buds at either pole. PH cells are unipolar, producing their second and subsequent buds only from the end opposite the junction with their mother. We propose that in PH cells a G2 cell-size checkpoint delays mitosis until bud size reaches that of the mother cell. We conclude that yeast and PH forms are distinct cell types each with a unique cell cycle, budding pattern, and cell shape.     

Representing crop rotations in life cycle assessment: a review of legume LCA studies

The International Journal of Life Cycle Assessment - There is an imperative to accurately assess the environmental sustainability of crop system interventions in the context of food security and...     

Functional genomics in the study of yeast cell polarity: moving in the right direction

The budding yeast Saccharomyces cerevisiae has been used extensively for the study of cell polarity, owing to both its experimental tractability and the high conservation of cell polarity and other basic biological processes among eukaryotes. The budding yeast has also served as a pioneer model organism for virtually all genome-scale approaches, including functional genomics, which aims to define gene function and biological pathways systematically through the analysis of high-throughput experimental data. Here, we outline the contributions of functional genomics and high-throughput methodologies to the study of cell polarity in the budding yeast. We integrate data from published genetic screens that use a variety of functional genomics approaches to query different aspects of polarity. Our integrated dataset is enriched for polarity processes, as well as some processes that are not intrinsically linked to cell polarity, and may provide new areas for future study.     

Community Attitudes and Practices of Urban Residents Regarding Predation by Pet Cats on Wildlife: An International Comparison

International differences in practices and attitudes regarding pet cats'' interactions with wildlife were assessed by surveying citizens from at least two cities in Australia, New Zealand, the UK, the USA, China and Japan. Predictions tested were: (i) cat owners would agree less than non-cat owners that cats might threaten wildlife, (ii) cat owners value wildlife less than non-cat owners, (iii) cat owners are less accepting of cat legislation/restrictions than non-owners, and (iv) respondents from regions with high endemic biodiversity (Australia, New Zealand, China and the USA state of Hawaii) would be most concerned about pet cats threatening wildlife. Everywhere non-owners were more likely than owners to agree that pet cats killing wildlife were a problem in cities, towns and rural areas. Agreement amongst non-owners was highest in Australia (95%) and New Zealand (78%) and lowest in the UK (38%). Irrespective of ownership, over 85% of respondents from all countries except China (65%) valued wildlife in cities, towns and rural areas. Non-owners advocated cat legislation more strongly than owners except in Japan. Australian non-owners were the most supportive (88%), followed by Chinese non-owners (80%) and Japanese owners (79.5%). The UK was least supportive (non-owners 43%, owners 25%). Many Australian (62%), New Zealand (51%) and Chinese owners (42%) agreed that pet cats killing wildlife in cities, towns and rural areas was a problem, while Hawaiian owners were similar to the mainland USA (20%). Thus high endemic biodiversity might contribute to attitudes in some, but not all, countries. Husbandry practices varied internationally, with predation highest where fewer cats were confined. Although the risk of wildlife population declines caused by pet cats justifies precautionary action, campaigns based on wildlife protection are unlikely to succeed outside Australia or New Zealand. Restrictions on roaming protect wildlife and benefit cat welfare, so welfare is a better rationale.     

Adapting Stand‐Alone Renewable Energy Technologies for the Circular Economy through Eco‐Design and Recycling

Renewable energy (RE) technologies are looked upon favorably to provide for future energy demands and reduce greenhouse gas (GHG) emissions. However, the installation of these technologies requires large quantities of finite material resources. We apply life cycle assessment to 100 years of electricity generation from three stand‐alone RE technologies—solar photovoltaics, run‐of‐river hydro, and wind—to evaluate environmental burden profiles against baseline electricity generation from fossil fuels. We then devised scenarios to incorporate circular economy (CE) improvements targeting hotspots in systems’ life cycle, specifically (1) improved recycling rates for raw materials and (ii) the application of eco‐design. Hydro presented the lowest environmental burdens per kilowatt‐hour of electricity generation compared with other RE technologies, owing to its higher efficiency and longer life spans for main components. Distinct results were observed in the environmental performance of each system based on the consideration of improved recycling rates and eco‐design. CE measures produced similar modest savings in already low GHG emissions burdens for each technology, while eco‐design specifically had the potential to provide significant savings in abiotic resource depletion. Further research to explore the full potential of CE measures for RE technologies will curtail the resource intensity of RE technologies required to mitigate climate change.     

Automation of mouse micronucleus genotoxicity assay by laser scanning cytometry

BACKGROUND: The evaluation of the safety of drugs and other chemicals is an important aspect of toxicology work. The mouse micronucleus assay is a standard in vivo genotoxicity assay. Chromosomal damage is an indicator of genotoxicity, which manifests in the formation of micronuclei in polychromatic erythrocytes from bone marrow and in peripheral blood erythrocytes. The assay is laborious to perform by manual counting. The laser scanning cytometer allows automated and rapid quantitation of cellular and subcellular fluorescence in monodisperse cell samples on a microscope slide. The object of this study was to evaluate the application of this new technology in the mouse micronucleus genotoxicity assay. Materials and Methods One hundred forty-four mice of various strains were dosed with combinations of carcinogens and antioxidants. Duplicate blood films were prepared 3 days later. One set of slides was stained with acridine orange, and the proportion of micronucleated erythrocytes was counted in 5,000 cells per slide. The duplicates were stained with propidium iodide (40 microg/ml). Five thousand cells per sample were examined using a laser scanning cytometer. The proportion of micronucleated erythrocytes was measured. RESULTS: A coefficient of correlation of 0.96 was found between the data from the two assays. The automation of the assay on the LSC produced a considerable time saving and efficiency gain. CONCLUSIONS: We conclude that with further development, laser scanning cytometry is likely to become the preferred modality for the performance of standard genotoxicity assays.