In the present work we study how the number of simulated customers (occupancy) affects social distance in an ideal supermarket, considering realistic typical dimensions and processing times (product ...selection and checkout). From the simulated trajectories we measure social distance events of less than 2 m, and their duration. Among other observables, we define a physical distance coefficient that informs how many events (of a given duration) each agent experiences.
•The function of crib-biting (CB) behaviour is poorly understood.•We compared the performance of CB versus control (C) horses in frustrating tasks.•CB horses had lower salivary cortisol values ...compared to other horses.•CB horses were also less likely to display behaviours indicating frustration.•Our results suggest that CB is a coping strategy serving to reduce stress.
Stereotypies are common in captive animals, but it remains unclear if they are pathological by-products of captive conditions or if they have an adaptive function. Here, we address this question using crib-biting, a common type of stereotypic behaviour in domestic horses, thought to result from stressful or frustrating environments. Since chronic stress is known to affect learning abilities via dopaminergic modulation in the basal ganglia, we predicted that stereotypic horses would underperform in learning tasks compared to healthy control animals, in line with the pathological by-product hypothesis. We exposed 19 crib-biters and 18 control horses in six spatial tasks, and collected behavioural and physiological data (heart rate, heart rate variability and salivary cortisol) to assess learning performance and stress levels. We found that, during the learning phase, 10 of 19 crib-biters showed stereotypic behaviour. Surprisingly, crib-biters that displayed the stereotypic behaviour (Group A) had lower salivary cortisol values compared to crib-biters that did not display the stereotypic behaviour (Group B) or control horses (Group C), after the first part of the experiment. In addition, a smaller proportion of horses in Group A displayed behaviours indicating frustration during one of the test compared to Group B. Moreover, we found no difference between the three groups in their learning performance nor in their heart rate or heart rate variability measures. Our results therefore suggest that crib-biting has an adaptive function and can help horses to reduce stress and frustration during learning tasks, which then enables them to show normal learning performance.
Fine-scale knowledge of the changes in composition and function of the human gut microbiome compared that of our closest relatives is critical for understanding the evolutionary processes underlying ...its developmental trajectory. To infer taxonomic and functional changes in the gut microbiome across hominids at different timescales, we perform high-resolution metagenomic-based analyzes of the fecal microbiome from over two hundred samples including diverse human populations, as well as wild-living chimpanzees, bonobos, and gorillas. We find human-associated taxa depleted within non-human apes and patterns of host-specific gut microbiota, suggesting the widespread acquisition of novel microbial clades along the evolutionary divergence of hosts. In contrast, we reveal multiple lines of evidence for a pervasive loss of diversity in human populations in correlation with a high Human Development Index, including evolutionarily conserved clades. Similarly, patterns of co-phylogeny between microbes and hosts are found to be disrupted in humans. Together with identifying individual microbial taxa and functional adaptations that correlate to host phylogeny, these findings offer insights into specific candidates playing a role in the diverging trajectories of the gut microbiome of hominids. We find that repeated horizontal gene transfer and gene loss, as well as the adaptation to transient microaerobic conditions appear to have played a role in the evolution of the human gut microbiome.
The coronavirus disease 2019 (COVID-19) pandemic is a major worldwide health disorder. There is an increasing number of neurological complications recognized with COVID-19 including patients with GBS ...and its variants.
A review of the clinical cases of GBS associated to COVID-19 infection published in the last months has been developed. We included 48 patients (31 men, mean age 56.4 years). The most common COVID-19 symptoms were cough (60.4%) and fever (56.3%). Mean time from COVID-19 symptoms to neurologic manifestations was 12.1 days, but in nine patients (18.8%) developed GBS within seven days. Eleven patients (22.9%) presented cranial nerve involvement in the absence of muscle weakness; 36 presented the classic sensory motor variant (75%) and one had a pure motor variant (2.1%). The electrodiagnostic pattern was considered demyelinating in 82.4% of the generalized variants. The presence of hyposmia/dysgeusia was associated with a latency shorter than seven days to GBS onset of symptoms (30% vs 15.6%), and cranial nerve involvement in the absence of weakness (30.8% vs 17.1%). Most patients (87.5%) were treated with intravenous immunoglobulin. Neurological outcome was favorable in 64.6%; 29.2% had respiratory failure and 4.2% died shortly after being admitted.
GBS in patients with SARS-CoV-2 infection resembles clinically and electrophysiology the classical forms. Further studies are necessary to understand whether GBS frequency is actually increased due to SARS-CoV-2 infection and explore pathogenic mechanisms.
It has long been hypothesized that polyomaviruses (PyV; family Polyomaviridae) codiverged with their animal hosts. In contrast, recent analyses suggested that codivergence may only marginally ...influence the evolution of PyV. We reassess this question by focusing on a single lineage of PyV infecting hominine hosts, the Merkel cell polyomavirus (MCPyV) lineage. By characterizing the genetic diversity of these viruses in seven African great ape taxa, we show that they exhibit very strong host specificity. Reconciliation analyses identify more codivergence than noncodivergence events. In addition, we find that a number of host and PyV divergence events are synchronous. Collectively, our results support codivergence as the dominant process at play during the evolution of the MCPyV lineage. More generally, our results add to the growing body of evidence suggesting an ancient and stable association of PyV and their animal hosts.
The processes involved in viral evolution and the interaction of viruses with their hosts are of great scientific interest and public health relevance. It has long been thought that the genetic diversity of double-stranded DNA viruses was generated over long periods of time, similar to typical host evolutionary timescales. This was also hypothesized for polyomaviruses (family Polyomaviridae), a group comprising several human pathogens, but this remains a point of controversy. Here, we investigate this question by focusing on a single lineage of polyomaviruses that infect both humans and their closest relatives, the African great apes. We show that these viruses exhibit considerable host specificity and that their evolution largely mirrors that of their hosts, suggesting that codivergence with their hosts played a major role in their diversification. Our results provide statistical evidence in favor of an association of polyomaviruses and their hosts over millions of years.
Purpose:
To assess the short-term prognosis of patients with recent symptomatic intracranial atherosclerotic disease in the posterior circulation and evaluate differences in the outcome of patients ...receiving medical or endovascular treatment.
Methods:
The records of 50 consecutive patients with symptomatic intracranial atherosclerotic disease in the posterior circulation were reviewed to record the occurrence of transient ischemic attack, stroke, major bleeding, and/or death during the 12-month period following a neurological event. Twenty-five patients received medical treatment alone, 13 initially received medical treatment and subsequently were treated with angioplasty/stenting due to recurrent events (analyzed in both groups), and 12 patients received endovascular treatment initially. The crossover patients were considered as 1 treated patient in each group; thus, there were 38 subjects (33 men; mean age 68±9 years) receiving medical therapy compared with 25 patients (21 men; mean age 63± 13 years) who underwent endovascular procedures.
Results:
During the 12-month period, subjects in the medically-treated group had a higher rate of events (37%, 14/38) than patients who received angioplasty/stenting (12%, 3/25; p=0.042). Notably, there were 7 (18%) TIAs and 6 (16%) strokes in medically-treated patients versus no TIAs (0%, p = 0.035) and only 2 (8%, p = NS) strokes in the endovascular group, both of which occurred within 48 hours of the procedure. There were no deaths and only a single major bleeding event in each group.
Conclusion:
Endovascular treatment of patients with symptomatic intracranial disease of the posterior territory appears to be associated with a substantially better outcome.
Cysteine proteases are widespread in all life kingdoms, being central to diverse physiological processes based on a broad range of substrate specificity. Paralogous
Fasciola hepatica
cathepsin L ...proteases are essential to parasite invasion, tissue migration and reproduction. In spite of similarities in their overall sequence and structure, these enzymes often exhibit different substrate specificity. These preferences are principally determined by the amino acid composition of the active site's S
2
subsite (pocket) of the enzyme that interacts with the substrate P
2
residue (Schetcher and Berger nomenclature). Although secreted
Fh
CL1 accommodates aliphatic residues in the S
2
pocket,
Fh
CL2 is also efficient in cleaving proline in that position. To understand these differences, we engineered the
Fh
CL1 S
2
subsite at three amino acid positions to render it identical to that present in
Fh
CL2. The substitutions did not produce the expected increment in proline accommodation in P
2.
Rather, they decreased the enzyme's catalytic efficiency toward synthetic peptides. Nonetheless, a change in the P
3
specificity was associated with the mutation of Leu67 to Tyr, a hinge residue between the S
2
and S
3
subsites that contributes to the accommodation of Gly in S
3
. Molecular dynamic simulations highlighted changes in the spatial distribution and secondary structure of the S
2
and S
3
pockets of the mutant
Fh
CL1 enzymes. The reduced affinity and catalytic efficiency of the mutant enzymes may be due to a narrowing of the active site cleft that hinders the accommodation of substrates. Because the variations in the enzymatic activity measured could not be exclusively allocated to those residues lining the active site, other more external positions might modulate enzyme conformation, and, therefore, catalytic activity.
Cysteine proteases are widespread in all life kingdoms, being central to diverse physiological processes based on a broad range of substrate specificity. Paralogous
cathepsin L proteases are ...essential to parasite invasion, tissue migration and reproduction. In spite of similarities in their overall sequence and structure, these enzymes often exhibit different substrate specificity. These preferences are principally determined by the amino acid composition of the active site's S
subsite (pocket) of the enzyme that interacts with the substrate P
residue (Schetcher and Berger nomenclature). Although secreted
CL1 accommodates aliphatic residues in the S
pocket,
CL2 is also efficient in cleaving proline in that position. To understand these differences, we engineered the
CL1 S
subsite at three amino acid positions to render it identical to that present in
CL2. The substitutions did not produce the expected increment in proline accommodation in P
Rather, they decreased the enzyme's catalytic efficiency toward synthetic peptides. Nonetheless, a change in the P
specificity was associated with the mutation of Leu67 to Tyr, a hinge residue between the S
and S
subsites that contributes to the accommodation of Gly in S
. Molecular dynamic simulations highlighted changes in the spatial distribution and secondary structure of the S
and S
pockets of the mutant
CL1 enzymes. The reduced affinity and catalytic efficiency of the mutant enzymes may be due to a narrowing of the active site cleft that hinders the accommodation of substrates. Because the variations in the enzymatic activity measured could not be exclusively allocated to those residues lining the active site, other more external positions might modulate enzyme conformation, and, therefore, catalytic activity.
PDF
