RÉSUMÉ
Climate warming creates energetic challenges for endothermic species by increasing metabolic and hydric costs of thermoregulation. Although endotherms can invoke an array of behavioural and physiological strategies for maintaining homeostasis, the relative effectiveness of those strategies in a climate that is becoming both warmer and drier is not well understood. In accordance with the heat dissipation limit theory which suggests that allocation of energy to growth and reproduction by endotherms is constrained by the ability to dissipate heat, we expected that patterns of habitat use by large, heat-sensitive mammals across multiple scales are critical for behavioural thermoregulation during periods of potential heat stress and that they must invest a large portion of time to maintain heat balance. To test our predictions, we evaluated mechanisms underpinning the effectiveness of bed sites for ameliorating daytime heat loads and potential heat stress across the landscape while accounting for other factors known to affect behaviour. We integrated detailed data on microclimate and animal attributes of moose Alces alces, into a biophysical model to quantify costs of thermoregulation at fine and coarse spatial scales. During summer, moose spent an average of 67.8% of daylight hours bedded, and selected bed sites and home ranges that reduced risk of experiencing heat stress. For most of the day, shade could effectively mitigate the risk of experiencing heat stress up to 10°C, but at warmer temperatures (up to 20°C) wet soil was necessary to maintain homeostasis via conductive heat loss. Consistent selection across spatial scales for locations that reduced heat load underscores the importance of the thermal environment as a driver of behaviour in this heat-sensitive mammal. Moose in North America have long been characterized as riparian-obligate species because of their dependence on woody plant species for food. Nevertheless, the importance of dissipating endogenous heat loads conductively through wet soil suggests riparian habitats also are critical thermal refuges for moose. Such refuges may be especially important in the face of a warming climate in which both high environmental temperatures and drier conditions will likely exacerbate limits to heat dissipation, especially for large, heat-sensitive animals.
Sujet(s)
Cervidae , Écosystème , Animaux , Saisons , Température , Cervidae/physiologie , Sol , Changement climatiqueRÉSUMÉ
BioArt is a new discipline where artists employ materials and techniques of modern life sciences and create novel meanings of biology, often involving living organisms such as tissue culture, bacteria and yeasts, which may also be genetically engineered. The authors have engaged in a collaboration to develop 'Fermenting Futures', a project designed to explore the significance of yeast for early human history by enabling baking and brewing, all the way to industrial biotechnology and synthetic biology with their potential contributions to fight the climate change. Research in two of the authors' lab provides the materials and thematic lines for the artists to develop their installations. The two main pieces reflect on fermentation as a metabolic trait of baker's yeast and its enormous transformational power for human society, and on the application of synthetic biology to enable yeast to grow and produce materials from carbon dioxide. The role of BioArt to support public engagement and science dissemination is discussed, highlighting the importance of collaborations of scientists and artists on equal terms, as showcased here.
Sujet(s)
Biotechnologie , Saccharomyces cerevisiae , Fermentation , Génie génétique , Humains , Saccharomyces cerevisiae/génétique , Biologie synthétiqueRÉSUMÉ
BACKGROUND: Fungal coinfection is a recognized complication of respiratory virus infections, increasing morbidity and mortality, but can be readily treated if diagnosed early. An increasing number of small studies describing aspergillosis in coronavirus disease 2019 (COVID-19) patients with severe respiratory distress are being reported, but comprehensive data are lacking. The aim of this study was to determine the incidence, risk factors, and impact of invasive fungal disease in adult COVID-19 patients with severe respiratory distress. METHODS: An evaluation of a national, multicenter, prospective cohort evaluation of an enhanced testing strategy to diagnose invasive fungal disease in COVID-19 intensive care patients. Results were used to generate a mechanism to define aspergillosis in future COVID-19 patients. RESULTS: One-hundred and thirty-five adults (median age: 57, M/F: 2.2/1) were screened. The incidence was 26.7% (14.1% aspergillosis, 12.6% yeast infections). The overall mortality rate was 38%; 53% and 31% in patients with and without fungal disease, respectively (P = .0387). The mortality rate was reduced by the use of antifungal therapy (mortality: 38.5% in patients receiving therapy vs 90% in patients not receiving therapy (P = .008). The use of corticosteroids (P = .007) and history of chronic respiratory disease (P = .05) increased the likelihood of aspergillosis. CONCLUSIONS: Fungal disease occurs frequently in critically ill, mechanically ventilated COVID-19 patients. The survival benefit observed in patients receiving antifungal therapy implies that the proposed diagnostic and defining criteria are appropriate. Screening using a strategic diagnostic approach and antifungal prophylaxis of patients with risk factors will likely enhance the management of COVID-19 patients.
Sujet(s)
COVID-19 , Aspergillose pulmonaire invasive , Mycoses , Adulte , Humains , Unités de soins intensifs , Aspergillose pulmonaire invasive/diagnostic , Aspergillose pulmonaire invasive/traitement médicamenteux , Aspergillose pulmonaire invasive/épidémiologie , Adulte d'âge moyen , Mycoses/diagnostic , Mycoses/épidémiologie , Études prospectives , SARS-CoV-2RÉSUMÉ
Use of sexual and reproductive health (SRH) services is low amongst young people in Senegal. Although the evidence base on young people's SRH needs is growing, research on access to SRH services amongst young people with disabilities is negligible. Our study explored the SRH vulnerabilities and expressed needs for young people with disabilities, experiences of accessing SRH services and what access challenges they face. Male and female peer researchers conducted 17 focus group discussions and 50 interviews with young women and men with disabilities between 18 and 24 years with a physical, visual or hearing impairment in Dakar, Thies and Kaolack in Senegal. Young people with disabilities reported very low knowledge about, and use of, SRH services including contraception and gynaecological consultations, but demonstrated a need for them, and were reliant on others to accompany them to service providers, impeding their access to confidential services. Multiple cases of rape were revealed, particularly amongst women with hearing impairments. Key barriers to SRH services were financial barriers, provider attitudes and accessibility (related to their disability). SRH policies and interventions for young people with disabilities should be based on an understanding of the intersection of youth, disability and gender. Urgent and targeted action is needed to improve provider attitudes and capacity to respond to the needs of young people with disabilities and to address the burden of sexual violence.
Sujet(s)
Personnes handicapées/statistiques et données numériques , Accessibilité des services de santé/organisation et administration , Accessibilité des services de santé/statistiques et données numériques , Besoins et demandes de services de santé/organisation et administration , Besoins et demandes de services de santé/statistiques et données numériques , Services de santé génésique/statistiques et données numériques , Adolescent , Femelle , Groupes de discussion , Humains , Mâle , Recherche qualitative , Sénégal , Jeune adulteRÉSUMÉ
PURPOSE: We determined the extent to which complications as well as number of hospital-free days within 30 and 90 days of surgery predicted health related quality of life 1 year after radical cystectomy. MATERIALS AND METHODS: We used data from a prospective health related quality of life study using a validated instrument, the Vanderbilt Cystectomy Index-15. Complications were graded by the Clavien system, and hospital length of stay and length of stay during readmissions were used to calculate 30 and 90-day hospital-free days, respectively. We compared the number of hospital-free days among patients with varying levels of complications. Multivariate analysis was performed to determine predictors of Vanderbilt Cystectomy Index-15 score 1 year after surgery adjusting for demographic (age, gender, comorbidities) and clinical variables (stage and diversion type). RESULTS: A total of 100 patients with complete baseline and 1-year followup health related quality of life data were included in the analysis. Median (IQR) 30 and 90-day hospital-free days were 24 (22-25) and 84 (82-85), respectively. Patients who experienced any complications had significantly fewer 30-day hospital-free days (22 vs 24 days, p <0.01) and 90-day hospital-free days (81 vs 84 days, p <0.01), and patients with higher grade complications had fewer hospital-free days than those with lower grade or no complications (p <0.01). On multivariate analysis female gender and baseline Vanderbilt Cystectomy Index-15 score independently predicted higher 1-year health related quality of life scores. CONCLUSIONS: Patients who experience complications after radical cystectomy have fewer 30 and 90-day hospital-free days. However, neither predicts health related quality of life at 1 year. Instead, long-term health related quality of life appears to be driven largely by baseline health related quality of life and gender.
Sujet(s)
Cystectomie/effets indésirables , Sortie du patient/tendances , Réadmission du patient/tendances , Complications postopératoires/psychologie , Qualité de vie , Tumeurs de la vessie urinaire/chirurgie , Sujet âgé , Cystectomie/psychologie , Femelle , Études de suivi , Humains , Durée du séjour/tendances , Mâle , Complications postopératoires/épidémiologie , Études prospectives , Facteurs temps , Résultat thérapeutique , États-Unis/épidémiologieRÉSUMÉ
BACKGROUND: Over thirty years have passed since the Alma-Ata Declaration on primary health care in 1978. Many governments in the first decade following the declaration responded by developing national programmes of community health workers (CHWs), but evaluations of these often demonstrated poor outcomes. As many CHW programmes have responded to the HIV/AIDS pandemic, international interest in them has returned and their role in the response to other diseases should be examined carefully so that lessons can be applied to their new roles. Over half of the deaths in African children under five years of age are due to malaria, diarrhoea and pneumonia - a situation which could be addressed through the use of cheap and effective interventions delivered by CHWs. However, to date there is very little evidence from randomised controlled trials of the impacts of CHW programmes on child mortality in Africa. Evidence from non-randomised controlled studies has not previously been reviewed systematically. METHODS: We searched databases of published and unpublished studies for RCTs and non-randomised studies evaluating CHW programmes delivering curative treatments, with or without preventive components, for malaria, diarrhoea or pneumonia, in children in sub-Saharan Africa from 1987 to 2007. The impact of these programmes on morbidity or mortality in children under six years of age was reviewed. A descriptive analysis of interventional and contextual factors associated with these impacts was attempted. RESULTS: The review identified seven studies evaluating CHWs, delivering a range of interventions. Limited descriptive data on programmes, contexts or process outcomes for these CHW programmes were available. CHWs in national programmes achieved large mortality reductions of 63% and 36% respectively, when insecticide-treated nets and anti-malarial chemoprophylaxis were delivered, in addition to curative interventions. CONCLUSIONS: CHW programmes could potentially achieve large gains in child survival in sub-Saharan Africa if these programmes were implemented at scale. Large-scale rigorous studies, including RCTs, are urgently needed to provide policymakers with more evidence on the effects of CHWs delivering these interventions.
RÉSUMÉ
The iron- and manganese-containing superoxide dismutases (Fe/Mn-SOD) share the same chemical function and spatial structure but can be distinguished according to their modes of oligomerization and their metal ion specificity. They appear as homodimers or homotetramers and usually require a specific metal for activity. On the basis of 261 aligned SOD sequences and 12 superimposed x-ray structures, two phenetic trees were constructed, one sequence-based and the other structure-based. Their comparison reveals the imperfect correlation of sequence and structural changes; hyperthermophilicity requires the largest sequence alterations, whereas dimer/tetramer and manganese/iron specificities are induced by the most sizable structural differences within the monomers. A systematic investigation of sequence and structure characteristics conserved in all aligned SOD sequences or in subsets sharing common oligomeric and/or metal specificities was performed. Several residues were identified as guaranteeing the common function and dimeric conformation, others as determining the tetramer formation, and yet others as potentially responsible for metal specificity. Some form cation-pi interactions between an aromatic ring and a fully or partially positively charged group, suggesting that these interactions play a significant role in the structure and function of SOD enzymes. Dimer/tetramer- and iron/manganese-specific fingerprints were derived from the set of conserved residues; they can be used to propose selected residue substitutions in view of the experimental validation of our in silico derived hypotheses.
Sujet(s)
Protéines bactériennes , Superoxide dismutase , Séquence d'acides aminés , Protéines bactériennes/analyse , Protéines bactériennes/composition chimique , Protéines bactériennes/génétique , Séquence conservée , Fer , Manganèse , Données de séquences moléculaires , Conformation des protéines , Alignement de séquences , Superoxide dismutase/analyse , Superoxide dismutase/composition chimique , Superoxide dismutase/génétiqueRÉSUMÉ
It is often possible to identify sequence motifs that characterize a protein family in terms of its fold and/or function from aligned protein sequences. Such motifs can be used to search for new family members. Partitioning of sequence alignments into regions of similar amino acid variability is usually done by hand. Here, I present a completely automatic method for this purpose: one that is guaranteed to produce globally optimal solutions at all levels of partition granularity. The method is used to compare the tempo of sequence diversity across reliable three-dimensional (3D) structure-based alignments of 209 protein families (HOMSTRAD) and that for 69 superfamilies (CAMPASS). (The mean alignment length for HOMSTRAD and CAMPASS are very similar.) Surprisingly, the optimal segmentation distributions for the closely related proteins and distantly related ones are found to be very similar. Also, optimal segmentation identifies an unusual protein superfamily. Finally, protein 3D structure clues from the tempo of sequence diversity across alignments are examined. The method is general, and could be applied to any area of comparative biological sequence and 3D structure analysis where the constraint of the inherent linear organization of the data imposes an ordering on the set of objects to be clustered.
Sujet(s)
Biologie informatique , Protéines/composition chimique , Protéines/classification , Similitude de séquences d'acides aminés , Motifs d'acides aminés , Séquence conservée , Bases de données de protéines , Protéines/génétique , Alignement de séquencesRÉSUMÉ
MOTIVATION: Fold recognition programs align a probe protein sequence onto protein three-dimensional (3D) structure templates. The alignment between the probe sequence and the most suitable template can be used to predict the 3D structure and often biological function of the probe. Here we present a new threading scoring function of protein sequence-structure compatibility. An artificial neural network model is trained to predict compatibility of amino acid side-chains with structural environments. Log-odds scores of predicted probabilities from this model can then be used to construct protein sequence-structure alignments. RESULTS: Our model is tested on discrimination of native and decoy protein 3D structures. With a residue level structural description, its performance is comparable to those of pseudo-energy functions with atom level structural descriptions, better than the two functions with residue level structural descriptions. AVAILABILITY: The C++ source code of our neural network model is available at http://mathbio.nimr.mrc.ac.uk/~kxlin.
Sujet(s)
Modèles génétiques , Modèles moléculaires , , Pliage des protéines , Protéines/composition chimique , Alignement de séquences/méthodes , Séquence d'acides aminés , Bases de données de protéines , Modèles statistiques , Données de séquences moléculaires , Conformation des protéines , Protéines/génétique , Reproductibilité des résultats , Sensibilité et spécificité , Analyse de séquence de protéine/méthodes , Logiciel , Processus stochastiquesRÉSUMÉ
Bioinformatic software has used various numerical encoding schemes to describe amino acid sequences. Orthogonal encoding, employing 20 numbers to describe the amino acid type of one protein residue, is often used with artificial neural network (ANN) models. However, this can increase the model complexity, thus leading to difficulty in implementation and poor performance. Here, we use ANNs to derive encoding schemes for the amino acid types from protein three-dimensional structure alignments. Each of the 20 amino acid types is characterized with a few real numbers. Our schemes are tested on the simulation of amino acid substitution matrices. These simplified schemes outperform the orthogonal encoding on small data sets. Using one of these encoding schemes, we generate a colouring scheme for the amino acids in which comparable amino acids are in similar colours. We expect it to be useful for visual inspection and manual editing of protein multiple sequence alignments.