Cenomanian/Turonian benthic foraminiferal faunas of the Demerara Rise depth transect (ODP Leg 207)

Abstrac

Buoyancy regulation and aggregate formation in Amoebobacter purpureus from Mahoney lake

Abstract The meromictic Mahoney Lake (British Columbia, Canada) contains an extremely dense layer of purple sulfur bacteria (Amoebobacter purpureus). The buoyant density of Amoebobacter cells grown in pure culture at saturating light intensity was significantly higher (1027–1034 kg m−3) than the density of lake water (1015 kg m−3). When stationary cultures were shifted to the dark, the gas-vesicle content increased by a factor of 9 and buoyant density decreased to 1002 kg m−3 within three days. A novel mechanism of cell aggregation was detected for the Mahoney Lake strain. Dense cell aggregates were formed after depletion of sulfide. Formation of aggregates was correlated with an increase in cell surface hydrophobicity. Cell aggregates could be disintegrated within less than 1 s by addition of sulfide or various thiol compounds. Mercaptanes with a branched structure in the vicinity of the terminal thiol group, compounds with esterified thiol groups (methylmercaptanes), reducing compounds lacking thiol groups and detergents did not influence aggregate stability. Cell aggregates disintegrated upon addition of urea or of proteinase K. Addition of various sugars had no effect on aggregation; this points to the absence of lectins. The results indicate that cell-to-cell adhesion in A, purpureus ML1 is mainly caused by a hydrophobic effect and includes a specific mechanism possibly mediated by a surface protein. Extrapolation of laboratory results to field conditions demonstrated that both regulation of buoyant density and formation of cell aggregates result in passive accumulation of cells at the chemocline and contribute to the narrow stratification of A. purpureus in Mahoney Lake

Use of elicitors as an approach for sustainable agriculture

Plant pathogens are responsible for large declines in agricultural production. Their control is carried out mainly by chemical and frequently proposed biological methods to reduce their environmental impact. On the other hand, plant-pathogen or microbe interactions generate multiple signals within plants activating defense mechanism, some of which can also be induced by elicitors (protective molecules). Elicitor-induced plant signaling serves as a guide to a series of intracellular events that end in activation of transduction cascades and hormonal pathways triggering induced resistance (IR) and consequently activation of plant immunity to environmental stresses. So, it is necessary to understand where and how elicitors act in cellular defense mechanism of crops, to improve protection and management for sustainable crop. Therefore this review focused on main topics that guide induced resistance and therefore activation of plant immune response.Keywords: Elicitors, defense mechanism, Immune response, Induced resistance, MAP

Analogies between geminivirus and oncovirus: Cell cycle regulation

Geminiviruses are a large family of plant viruses whose genome is composed of one or two circular and single strand of DNA. They replicate in the cell nucleus being Rep protein, the only viral protein necessary for their replication process. Geminiviruses as same as animal DNA oncoviruses, like SV40, adenovirus and papillomavirus, use the host replication machinery to replicate their DNA. Consequently, they alter host cell cycle regulation to create a suitable environment for their replication. One of the events involved in this alteration would be the inactivation of the retinoblastoma protein (pRb) that negatively regulates the G1/S transition in cells. The discovery of one homologue of the pRb in plants and the finding that Rep protein of some geminiviruses interacts with human retinoblastoma protein, as well as animal virus oncoproteins, is very interesting. This finding laid the groundwork for subsequent detection of analogies between geminiviruses and animal DNA tumor viruses, especially in their interaction with pRb. Moreover, the finding allowed the determination of how this interaction affects the regulation of the cell cycle in plants and animals. Accumulated knowledge generates new interesting questions and possible implications, and so, in this document, we dare to watch in that direction.Key words: Geminivirus, oncovirus, retinoblastoma protein, cell cycle regulation, endoreduplication

Evaluation of the effect of patient education on rates of falls in older hospital patients: Description of a randomised controlled trial

Background. Accidental falls by older patients in hospital are one of the most commonly reported adverse events. Falls after discharge are also common. These falls have enormous physical, psychological and social consequences for older patients, including serious physical injury and reduced quality of life, and are also a source of substantial cost to health systems worldwide. There have been a limited number of randomised controlled trials, mainly using multifactorial interventions, aiming to prevent older people falling whilst inpatients. Trials to date have produced conflicting results and recent meta-analyses highlight that there is still insufficient evidence to clearly identify which interventions may reduce the rate of falls, and falls related injuries, in this population. Methods and design. A prospective randomised controlled trial (n = 1206) is being conducted at two hospitals in Australia. Patients are eligible to be included in the trial if they are over 60 years of age and they, or their family or guardian, give written consent. Participants are randomised into three groups. The control group continues to receive usual care. Both intervention groups receive a specifically designed patient education intervention on minimising falls in addition to usual care. The education is delivered by Digital Video Disc (DVD) and written workbook and aims to promote falls prevention activities by participants. One of the intervention groups also receives follow up education training visits by a health professional. Blinded assessors conduct baseline and discharge assessments and follow up participants for 6 months after discharge. The primary outcome measure is falls by participants in hospital. Secondary outcome measures include falls at home after discharge, knowledge of falls prevention strategies and motivation to engage in falls prevention activities after discharge. All analyses will be based on intention to treat principle. Discussion. This trial will examine the effect of a single intervention (specifically designed patient education) on rates of falls in older patients in hospital and after discharge. The results will provide robust recommendations for clinicians and researchers about the role of patient education in this population. The study has the potential to identify a new intervention that may reduce rates of falls in older hospital patients and could be readily duplicated and applied in a wide range of clinical settings. Trial Registration. ACTRN12608000015347

Prestin is an anion transporter dispensable for mechanical feedback amplification in Drosophila hearing.

In mammals, the membrane-based protein Prestin confers unique electromotile properties to cochlear outer hair cells, which contribute to the cochlear amplifier. Like mammals, the ears of insects, such as those of Drosophila melanogaster, mechanically amplify sound stimuli and have also been reported to express Prestin homologs. To determine whether the D. melanogaster Prestin homolog (dpres) is required for auditory amplification, we generated and analyzed dpres mutant flies. We found that dpres is robustly expressed in the fly's antennal ear. However, dpres mutant flies show normal auditory nerve responses, and intact non-linear amplification. Thus we conclude that, in D. melanogaster, auditory amplification is independent of Prestin. This finding resonates with prior phylogenetic analyses, which suggest that the derived motor function of mammalian Prestin replaced, or amended, an ancestral transport function. Indeed, we show that dpres encodes a functional anion transporter. Interestingly, the acquired new motor function in the phylogenetic lineage leading to birds and mammals coincides with loss of the mechanotransducer channel NompC (=TRPN1), which has been shown to be required for auditory amplification in flies. The advent of Prestin (or loss of NompC, respectively) may thus mark an evolutionary transition from a transducer-based to a Prestin-based mechanism of auditory amplification

Entrepreneurial sons, patriarchy and the Colonels' experiment in Thessaly, rural Greece

Existing studies within the field of institutional entrepreneurship explore how entrepreneurs influence change in economic institutions. This paper turns the attention of scholarly inquiry on the antecedents of deinstitutionalization and more specifically, the influence of entrepreneurship in shaping social institutions such as patriarchy. The paper draws from the findings of ethnographic work in two Greek lowland village communities during the military Dictatorship (1967–1974). Paradoxically this era associated with the spread of mechanization, cheap credit, revaluation of labour and clear means-ends relations, signalled entrepreneurial sons’ individuated dissent and activism who were now able to question the Patriarch’s authority, recognize opportunities and act as unintentional agents of deinstitutionalization. A ‘different’ model of institutional change is presented here, where politics intersects with entrepreneurs, in changing social institutions. This model discusses the external drivers of institutional atrophy and how handling dissensus (and its varieties over historical time) is instrumental in enabling institutional entrepreneurship

Mammography screening: views from women and primary care physicians in Crete

Background: Breast cancer is the most commonly diagnosed cancer among women and a leading cause of death from cancer in women in Europe. Although breast cancer incidence is on the rise worldwide, breast cancer mortality over the past 25 years has been stable or decreasing in some countries and a fall in breast cancer mortality rates in most European countries in the 1990s was reported by several studies, in contrast, in Greece have not reported these favourable trends. In Greece, the age-standardised incidence and mortality rate for breast cancer per 100.000 in 2006 was 81,8 and 21,7 and although it is lower than most other countries in Europe, the fall in breast cancer mortality that observed has not been as great as in other European countries. There is no national strategy for screening in this country. This study reports on the use of mammography among middleaged women in rural Crete and investigates barriers to mammography screening encountered by women and their primary care physicians. Methods: Design: Semi-structured individual interviews. Setting and participants: Thirty women between 45–65 years of age, with a mean age of 54,6 years, and standard deviation 6,8 from rural areas of Crete and 28 qualified primary care physicians, with a mean age of 44,7 years and standard deviation 7,0 serving this rural population. Main outcome measure: Qualitative thematic analysis. Results: Most women identified several reasons for not using mammography. These included poor knowledge of the benefits and indications for mammography screening, fear of pain during the procedure, fear of a serious diagnosis, embarrassment, stress while anticipating the results, cost and lack of physician recommendation. Physicians identified difficulties in scheduling an appointment as one reason women did not use mammography and both women and physicians identified distance from the screening site, transportation problems and the absence of symptoms as reasons for non-use. Conclusion: Women are inhibited from participating in mammography screening in rural Crete. The provision of more accessible screening services may improve this. However physician recommendation is important in overcoming women's inhibitions. Primary care physicians serving rural areas need to be aware of barriers preventing women from attending mammography screening and provide women with information and advice in a sensitive way so women can make informed decisions regarding breast caner screening

Does Medical Students' Preference of Test Format (Computer-based vs. Paper-based) have an Influence on Performance?

<p>Abstract</p> <p>Background</p> <p>Computer-based examinations (CBE) ensure higher efficiency with respect to producibility and assessment compared to paper-based examinations (PBE). However, students often have objections against CBE and are afraid of getting poorer results in a CBE.</p> <p>The aims of this study were (1) to assess the readiness and the objections of students to a CBE vs. PBE (2) to examine the acceptance and satisfaction with the CBE on a voluntary basis, and (3) to compare the results of the examinations, which were conducted in different formats.</p> <p>Methods</p> <p>Fifth year medical students were introduced to an examination-player and were free to choose their format for the test. The reason behind the choice of the format as well as the satisfaction with the choice was evaluated after the test with a questionnaire. Additionally, the expected and achieved examination results were measured.</p> <p>Results</p> <p>Out of 98 students, 36 voluntarily chose a CBE (37%), 62 students chose a PBE (63%). Both groups did not differ concerning sex, computer-experience, their achieved examination results of the test, and their satisfaction with the chosen format. Reasons for the students' objections against CBE include the possibility for outlines or written notices, a better overview, additional noise from the keyboard or missing habits normally present in a paper based exam. The students with the CBE tended to judge their examination to be more clear and understandable. Moreover, they saw their results to be independent of the format.</p> <p>Conclusions</p> <p>Voluntary computer-based examinations lead to equal test scores compared to a paper-based format.</p