Can microorganisms survive upon high-temperature heating during the interplanetary transfer by meteorites?

One of the most important aspects of the problem of life transfer in the cosmic space is the resistance of microorganisms to high-temperature heating during the launch and entry into the atmosphere. The high-temperature limits of the survival of microorganisms were studied under conditions modeling the laungh from the Mars and the landing on the Earth. Two strain of E. coli K12 exposed to short heating pulse were studied in order to tind out if they could resist high temperature while being in the desiccated state. The procedure was performed in vacuum. It was found that a fraction of bacteria survive heating pulses up to 250 degrees C in vacuum, while similar heating at normal atmospheric pressure leads to the total sterilization of samples.     

Can geriatrics survive?

Geriatrics has consistently failed to attract enough staff, and hence geriatric units often cannot provide a full service for the elderly. Meanwhile beds in general medical units may be blocked by elderly patients. This division between geriatric and medical units is arbitrary and wasteful. There are no clinical processes or techniques unique to geriatrics, which is probably why the specialty is unattractive; few doctors want to confine their attention only to the elderly. Geriatrics as a separate specialty should therefore be largely abandoned and the care of the elderly reintegrated into general medicine.     

Can Coxiella burnetii be transmitted by embryo transfer in goats?

The detection of significant bacterial loads of Coxiella burnetii in flushing media and tissue samples from the genital tracts of nonpregnant goats represents a risk factor for in utero infection and transmission during embryo transfer. The aim of this study was to investigate (1) whether cells of early goat embryos isolated from in vivo–fertilized goats interact with C. burnetii in vitro, (2) whether the embryonic zona pellucida (ZP) protects early embryo cells from infection, and (3) the efficacy of the International Embryo Transfer Society (IETS) washing protocol for bovine embryos. The study was performed in triple replicate: 12 donor goats, certified negative by ELISA and polymerase chain reaction, were synchronized, superovulated, and subsequently inseminated by Q fever-negative males. Sixty-eight embryos were collected 4 days later by laparotomy. Two-thirds of the resulting ZP-intact and ZP-free 8- to 16-cell embryos (9-9, 11-11, and 4-4 in replicates 1, 2, and 3, respectively) were placed in 1 mL minimum essential medium containing 10⁹C. burnetii CBC1 (IASP, INRA Tours). After overnight incubation at 37 °C and 5% CO₂, the embryos were washed according to the IETS procedure. In parallel, the remaining third ZP-intact and ZP-free uninfected embryos (3-3, 5-5, and 2-2 in replicates 1, 2, and 3, respectively) were subjected to the same procedures, but without C. burnetii, thus serving as controls. The 10 washing fluids for all batches of each replicate were collected and centrifuged for 1 hour at 13,000 × g. The washed embryos and pellets were tested by polymerase chain reaction. Coxiella burnetii DNA was found in all batches of ZP-intact and ZP-free infected embryos after 10 successive washes. It was also detected in the first five washing fluids for ZP-intact embryos and in the first eight washing fluids for ZP-free embryos. None of the control batches (embryos and washing fluids) were found to contain bacterial DNA. These results clearly indicate that caprine early embryonic cells are susceptible to infection by C. burnetii. The bacterium shows a strong tendency to adhere to the ZP after in vitro infection, and the washing procedure recommended by the IETS for bovine embryos failed to remove it. The persistence of these bacteria makes the embryo a potential means of transmission to recipient goats. Further studies are needed to investigate whether the enzymatic treatment of caprine embryos infected by C. burnetii would eliminate the bacteria from the ZP.     

Can fish survive by filter-feeding on microparticles? Energy balance in tilapia grazing on algal suspensions

Data on dietary preferences, filter-feeding mechanisms and ingestion rates of algae by tilapias are outlined and discussed. Quantitative data on algal ingestion by filter-feeding are incorporated into a bioenergetic model, demonstrating that under most conditions tilapias are unable to fulfil basic maintenance requirements and hence lose weight. It is concluded that the apparently high volumes of algae ingested by tilapias must be achieved by other means, by particulate feeding on aggregations of algae in the water column or flocculent surface scums of cyanobacteria or by grazing on periphytic mats.     

Can the academic background of medical graduates be detected during internship?

Performance ratings were obtained by the clinical supervisors of four graduated classes of McMaster University medical students during internship. The supervisors detected no difference in performance between the graduates who met the "traditional" admissions criteria (both an undergraduate grade point average of 3.1 or greater on a 4-point scale and previous training in biology, general and organic chemistry, and physics) and those who lacked one or both of these prerequisites. These data suggest that medical schools can expand their admissions criteria without fearing that their graduates will perform less well as interns because of a lack of traditional academic preparation for medical school.     

Can conditions experienced during migration limit the population levels of birds?

Populations of migratory birds are usually considered to be limited by conditions in breeding or wintering areas, but some might be limited by conditions encountered on migration. This could occur at stopover sites where competition for restricted food supplies can reduce subsequent survival or breeding success, or during the flights themselves, when adverse weather can occasionally kill large numbers of individuals. Competition for food could act in a density-dependent manner and help to regulate populations, whereas weather effects are more likely to act in a density-independent manner. The evidence for these views is explored in this paper. When preparing for migration, birds must normally obtain more food per day than usual, in order to accumulate the body reserves that fuel their flights. Birds often concentrate in large numbers at particular stopover sites, where food can become scarce, thus affecting migratory performance. Rates of weight gain, departure weights, and stopover durations often correlate with food supplies at stopover sites, sometimes influencing the subsequent survival and reproductive success of individuals, which can in turn affect subsequent breeding numbers. Many studies have provided evidence for interference and depletion competition at stopover sites, relatively few for migration conditions influencing the subsequent breeding or survival of individuals, and even fewer for effects on subsequent breeding numbers. Migrants in flight occasionally suffer substantial mortality in storms, especially over water, sometimes involving many thousands of birds at a time. Other mass mortalities have resulted from atypical ‘winter-like’ weather, occurring soon after the arrival of summer migrants in their breeding areas or just before their departure in autumn. Again, many thousands of birds at a time have been killed in such incidents, causing reductions of 30–90% in local breeding densities. In some bird species, migration-related events can at times have substantial effects on the year-to-year changes in breeding population levels. Nonetheless, the difficulties involved in investigating migrating birds at different points on their migration routes have so far limited the number of studies on the influence of events during migration periods on population levels.     

Can freshwater planktonic ciliates survive on a diet of picoplankton?

Ciliate picoplanktivory was studied in two different freshwatersystems with abundant autotrophic picoplankton (APP): the eutrophic     

Can the grey mould disease of the grape-vine be controlled by yeast?

Botrytis cinerea has been found to be highly pathogenic to 'Chardonnay' and 'Pinot noir' cultivars of the grape-vine producing the characteristic grey mould symptoms within 7 days of inoculation to the vitro-plants. The yeast Pichia anomala (strain FY-102), isolated from apple skin, was found to be antagonistic to B. cinerea as it completely inhibited the appearance of the grey mould symptoms when grown together. The yeast was responsible for morphological changes such as coagulation and leakage of the cytoplasm of B. cinerea. The pathogen, when applied together with P. anomala, failed to bring about the grey mould symptoms on the grape-vine, suggesting that the yeast could control the expression of this disease. An account of the interaction between B. cinerea and P. anomala, as well as the sequences of the complete ITS region of the ribosomal DNA of the yeast are described here.     

Can asthma control be improved by understanding the patient's perspective?

Background

Clinical trials show that asthma can be controlled in the majority of patients, but poorly controlled asthma still imposes a considerable burden. The level of asthma control achieved reflects the behaviour of both healthcare professionals and patients. A key challenge for healthcare professionals is to help patients to engage in self-management behaviours with optimal adherence to appropriate treatment. These issues are particularly relevant in primary care, where most asthma is managed. An international panel of experts invited by the International Primary Care Respiratory Group considered the evidence and discussed the implications for primary care practice.

Discussion

Causes of poor control Clinical factors such as exposure to triggers and concomitant rhinitis are important but so are patient behavioural factors. Behaviours such as smoking and nonadherence may reduce the efficacy of treatment and patients' perceptions influence these behaviours. Perceptual barriers to adherence include doubting the need for treatment when symptoms are absent and concerns about potential adverse effects. Under-treatment may also be related to patients' underestimation of the significance of symptoms, and lack of awareness of achievable control. Implications Three key implications for healthcare professionals emerged from the debate. First, the need for simple tools to assess asthma control. Two approaches considered were the monitoring of biometric markers of control and questionnaires to record patient-reported outcomes. Second, to understand the reasons for poor control for individual patients, identifying both clinical (e.g. rhinitis) and behavioural factors (e.g. smoking and nonadherence to treatment). Third was the need to incorporate, within asthma review, an assessment of patient perspectives including their goals and aspirations and to elicit their beliefs and concerns about asthma and its treatment. This can be used as a basis for agreement between the healthcare professional and patient on a predefined target regarding asthma control and a treatment plan to achieve this.

Summary

Optimum review of asthma is essential to improve control. A key priority is the development of simple and effective tools for identifying poor control for individual patients coupled with a tailored approach to treatment to enable patients to set and achieve realistic goals for asthma control.     

Can dolphins heal by ultrasound?

In recent years, dolphin-assisted therapy has become very popular and an increasing number of facilities offer therapy programs with dolphins worldwide. To this date, there are no studies concerning the behavior of dolphins during these therapies. As a result of speculations that the echolocation of dolphins may play an important role for the success of the therapy and the high publicity of this in the media, people pay much more for dolphin-assisted than for other animal-assisted therapy programs. Based on publications in medicine, we will show that ultrasound emitted by dolphins could have an effect on biological tissue under some circumstances; such as sufficient intensity, repeated application over several days or weeks and a certain application duration per session. We recorded 83 sessions at the “Dolphins Plus”, a fenced area with ocean water in the Florida Keys. Our observations demonstrate that only one out of five observed dolphins behave significantly differently towards patients compared to other humans and that the duration of the observed close contacts did not meet the requirements for common ultrasound therapies.     

How do flies tolerate microorganisms in the gut?

Although gut epithelia are in constant contact with a large number of microbe-derived immune elicitors such as peptidoglycan, they do not mount an intense immune response. In this issue of Cell Host & Microbe, Lhocine et al. (2008) report that the PIMS gene product induces immune tolerance by reducing the availability of the peptidoglycan receptor in the plasma membrane. These findings provide a novel insight into the molecular mechanisms by which the host gut maintains balanced host-microbe interactions.     

Can biochemical properties serve as selective pressure for gene selection during inter-species and endosymbiotic lateral gene transfer?

During the evolution of endosymbiosis, only one orthologous gene, either from the invader or the invaded genome, is preserved. Genetic and environmental factors are usually invoked to explain this gene preference. How biochemical parameters can play a role in the selection of genes that code for enzymes that constitute a metabolic pathway is explored. Simple Michaelis-Menten-like enzymes are considered whose kinetic parameters are randomly generated to construct two parallel homologous pathways to account for the contributions of the invaded and the invader. Steady-state fluxes as targets of natural selection are focused. Enzymes are eliminated one by one so that the total flux through the pathway is least disturbed. Analysis of the results, done by different criteria, indicate that the maximal velocities, both forward and backward, are more influential in selection than the respective Michaelis constants. This inclination disappears as metabolite concentrations are increased. It is shown that kinetic selection criteria can result in a mosaicism of enzymes in the same pathway in terms of their genetic origin. Analysis of the results using the control coefficient paradigm disclosed an expected robust correlation between flux control coefficients of enzymes and their selective elimination. Similar analyses, performed for the case of single gene transfer or for gene replication with subsequent mutation, yielded essentially similar results. The results conform with the phenomenon of genetic mosaicism found in phylogenetic analyses of single or double endosymbioses and lateral gene transfer.     

Hypothesis--origin of parietal cells: transfer of the H+K+-ATPase gene from parasitic microorganisms to Cnidaria?

Parietal cells present in the stomach and terminal ileum secrete a highly-concentrated hydrochloric acid into the lumen. The cells are characterized by the enzyme P-type H+K+-ATPase, which has an alpha-subunit with a high homology (>85%) for the amino acid sequences of frog, mouse and pig stomachs. Gastric H+K+-ATPase also exhibits a high homology to H+-ATPase in yeast and Na+K+-ATPase in many tissues, suggesting origination from a common ancestral ATPase. It is known that parietal cells first appeared in fish and were later expressed in evolutionarily-higher organisms. Primitive organisms, such as Cnidaria and Ctenophora, that possessed digestive organs, but not parietal cells, were abundant in the ocean more than 600 million years ago (Pre-Cambrian period). The author thus hypothesized that the genes of either H+-ATPase or H+K+-ATPase that were present in parasitic microorganisms, such as yeast, were transferred to the interstitial cells of host organisms, such as Cnidaria, eventually leading to the evolution of parietal cells. It appears that although parietal cells in the stomach developed by chance, such cells have greatly contributed to the evolution of advanced organisms, including humans, by affording safe ingestion of a large volume of various foods.     

Can water responses in Stipa tenacissima L. during the summer season be promoted by non-rainfall water gains in soil?

This article reports on quantified soil water gains and their possible effects on summer water relationships in a semiarid Stipa tenacissima L. grasslands located in SE Spain. We believe that the net soil water gains detected using minilysimeters could be from soil water vapour adsorption (WVA). Our study of high water-stress showed stomatal conductance (21.8–43.1 mmol H₂O m⁻² s⁻¹) in S. tenacissima leaves unusual for the summer season, and the evapotranspiration from S. tenacissima grassland, estimated by a multi-source sparse evapotranspiration model, closely corresponding to total WVA. This highlights the importance of summer soil WVA to stomatal conductance and vital transpiration in S. tenacissima. This study measured pre-dawn leaf water potential (ψ) response to sporadic light rainfall, finding that a light summer rainfall (1.59 mm day⁻¹) was sufficient to vary ψ in S. tenacissima from −3.8 (close to the turgour loss point) to −2.7 MPa. We hypothesize that soil WVA can supply vegetation with water vital to its survival in seasons with a severe water deficit, giving rise to a close relationship between soil water dynamics and plant water response.     

Can We Disrupt the Sensing of Honey Bees by the Bee Parasite Varroa destructor?

BackgroundThe ectoparasitic mite, Varroa destructor, is considered to be one of the most significant threats to apiculture around the world. Chemical cues are known to play a significant role in the host-finding behavior of Varroa. The mites distinguish between bees from different task groups, and prefer nurses over foragers. We examined the possibility of disrupting the Varroa – honey bee interaction by targeting the mite''s olfactory system. In particular, we examined the effect of volatile compounds, ethers of cis 5-(2′-hydroxyethyl) cyclopent-2-en-1-ol or of dihydroquinone, resorcinol or catechol. We tested the effect of these compounds on the Varroa chemosensory organ by electrophysiology and on behavior in a choice bioassay. The electrophysiological studies were conducted on the isolated foreleg. In the behavioral bioassay, the mite''s preference between a nurse and a forager bee was evaluated.ConclusionsThese data indicate the potential of the selected compounds to disrupt the Varroa - honey bee associations, thus opening new avenues for Varroa control.     

Can the stereoselective effects of the anesthetic isoflurane be accounted for by lipid solubility?

Isoflurane is an inhalational general anesthetic widely used in surgical operations as a racemic mixture of its two optical isomers. The recent availability of pure enantiomers of isoflurane has encouraged their use in experimental studies, and stereoselective effects have now been observed on anesthetic-sensitive neuronal ion channels. Although it has been assumed that such chiral effects demonstrate direct interactions with proteins, it is possible that they could be due to stereoselective interactions with chiral membrane lipids. We have determined the partition coefficients of the two optical isomers of isoflurane between lipid bilayers and water, using racemic isoflurane and gas chromatography with a chiral column. For lipid bilayers of phosphatidylcholine (PC) and 4 mol% phosphatidic acid (PA), both with and without cholesterol (CHOL), we found equal partitioning of the isoflurane optical isomers. The ratios of the S(+) to R(-) isoflurane partition coefficients were (mean +/- SEM): 1.018 +/- 0.010 for bilayers of PC/CHOL/PA (mole ratios 56:40:4) and 1.011 +/- 0.002 for bilayers of PC/PA (mole ratio 96:4). Molar partition coefficients for racemic isoflurane were 49 +/- 4 and 165 +/- 10, respectively. These findings support the view that the stereoselective effects on ion channels observed with isoflurane are due to direct actions on proteins rather than lipids.     

Can estrogens promote hypertension during systemic lupus erythematosus?

SLE is a chronic autoimmune inflammatory disorder that predominantly affects young women. Based on this observation, it has been speculated that sex steroids, particularly estrogens, contribute to SLE disease progression. Young women with SLE are at an increased risk for the development of hypertension yet the reasons for this are unclear. One potential mechanism for the increased risk of hypertension during SLE is the chronic inflammation caused by immune complex mediated tissue injury. Estrogens are known to have an immunomodulatory role that can lead to the production of characteristic autoantibodies important for immune complex formation. Therefore, it is conceivable that during SLE estrogens contribute to tissue injury, increased inflammation and hypertension. This brief review discusses the increased risk for hypertension during SLE, the role of estrogens in immune system function, evidence for estrogens in SLE, and a possible link between estrogens and SLE hypertension.     

Are endophytic microorganisms involved in the stereoselective reduction of ketones by Daucus carota root?

Four strains of endophytic microorganisms isolated from carrot root were able to carry out the reduction of the carbonyl group with diverse degree of enantio-, and diasteroselectivity. Furthermore, biotransformation in the presence of bacterial inhibitor affects the stereochemical outcome of the reaction, and the concomitant addition of a yeast inhibitor results in a large decrease in the conversion percentage. These results indicate that endophytic microorganisms might be involved in the enantioselective reduction of ketones and ketoesters with fresh carrot root pieces.