Establishment of marine protected areas, including fully protected marine reserves, is one of the few management tools available for local communities to combat the deleterious effect of large scale ...environmental impacts, including global climate change, on ocean ecosystems. Despite the common hope that reserves play this role, empirical evidence of the effectiveness of local protection against global problems is lacking. Here we show that marine reserves increase the resilience of marine populations to a mass mortality event possibly caused by climate-driven hypoxia. Despite high and widespread adult mortality of benthic invertebrates in Baja California, Mexico, that affected populations both within and outside marine reserves, juvenile replenishment of the species that supports local economies, the pink abalone Haliotis corrugata, remained stable within reserves because of large body size and high egg production of the protected adults. Thus, local protection provided resilience through greater resistance and faster recovery of protected populations. Moreover, this benefit extended to adjacent unprotected areas through larval spillover across the edges of the reserves. While climate change mitigation is being debated, coastal communities have few tools to slow down negative impacts of global environmental shifts. These results show that marine protected areas can provide such protection.
Arthritogenic alphaviruses, such as Chikungunya virus (CHIKV), cause severe and debilitating rheumatic diseases worldwide, resulting in severe morbidity and economic costs. Recently, MXRA8 was ...reported as an entry receptor. Here, we present the crystal structures of the mouse MXRA8, human MXRA8 in complex with the CHIKV E protein, and the cryo-electron microscopy structure of human MXRA8 and CHIKV virus-like particle. MXRA8 has two Ig-like domains with unique structural topologies. This receptor binds in the “canyon” between two protomers of the E spike on the surface of the virion. The atomic details at the interface between the two binding entities reveal that both the two domains and the hinge region of MXRA8 are involved in interaction with CHIKV E1-E2 residues from two protomers. Notably, the stalk region of MXRA8 is critical for CHIKV virus entry. This finding provides important information regarding the development of therapeutic countermeasures against those arthritogenic alphaviruses.
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•MXRA8 has two Ig-like domains with an unexpected structural topology•MXRA8 binds in the “canyon” between two protomers of the CHIKV E spike•Both the two domains and hinge region of MXRA8 are involved in interaction•The stalk region of MXRA8 is critical for CHIKV virus entry
Structural insights into how Chikungunya virus binds its receptor on human cells provides a guide for developing antiviral therapies against arthritogenic alphaviruses.
An updated checklist of adult tapeworms (Platyhelminthes: Cestoda) that parasitize wild North American amphibians and reptiles is presented: A total of 58 species grouped in 15 genera, 5 families, ...and 3 orders, are registered; these infect a total of 90 species of reptiles and 88 species of amphibians in the region. An illustrated identification key for the families and genera listed is proposed.
A new genus and species of freshwater isopod is described from Pliocene volcanic sedimentary ashes found in an ancient lake basin in the Santa Rosa Dam region, Amatitlán, Jalisco, West-central ...Mexico. The new isopod is represented by a few corpses and molts. Due to the relatively poor preservation, no further morphological details can be offered to the moment, but the observed features are sufficient to distinguish this isopod from any living or fossil freshwater Sphaeromatidae species. This contribution extends the stratigraphic and geographic record of fossil isopod bearing localities in Mexico, being this the youngest fossil Peracarida recorded from this country.
Rhinoviruses (RVs) are the major cause of common cold, a respiratory disease that generally takes a mild course. However, occasionally, RV infection can lead to serious complications in patients ...debilitated by other ailments, e.g., asthma. Colds are a huge socioeconomic burden as neither vaccines nor other treatments are available. The many existing drug candidates either stabilize the capsid or inhibit the viral RNA polymerase, the viral proteinases, or the functions of other non-structural viral proteins; however, none has been approved by the FDA. Focusing on the genomic RNA as a possible target for antivirals, we asked whether stabilizing RNA secondary structures might inhibit the viral replication cycle. These secondary structures include G-quadruplexes (GQs), which are guanine-rich sequence stretches forming planar guanine tetrads via Hoogsteen base pairing with two or more of them stacking on top of each other; a number of small molecular drug candidates increase the energy required for their unfolding. The propensity of G-quadruplex formation can be predicted with bioinformatics tools and is expressed as a GQ score. Synthetic RNA oligonucleotides derived from the RV-A2 genome with sequences corresponding to the highest and lowest GQ scores indeed exhibited characteristics of GQs. In vivo, the GQ-stabilizing compounds, pyridostatin and PhenDC3, interfered with viral uncoating in Na
but not in K
-containing phosphate buffers. The thermostability studies and ultrastructural imaging of protein-free viral RNA cores suggest that Na
keeps the encapsulated genome more open, allowing PDS and PhenDC3 to diffuse into the quasi-crystalline RNA and promote the formation and/or stabilization of GQs; the resulting conformational changes impair RNA unraveling and release from the virion. Preliminary reports have been published.
Cardiovascular diseases (CVDs), especially arterial hypertension, stand as prominent contributors to global mortality. Regrettably, individuals with diabetes encounter a two-fold increase in the risk ...of mortality associated with CVDs. Hydrochlorothiazide (HCTZ) represents a primary intervention for hypertension, particularly in diabetic patients. Nevertheless, there has not yet been a comprehensive assessment of the biophysical characteristics regarding the impact of glucose levels on its binding affinity with human serum albumin (HSA). Thus, the present work reports the interactive profile of HSA/HCTZ in nonglycemic, normoglycemic (80 mg/dL), and hyperglycemic (320 mg/dL) conditions by time-resolved fluorescence, saturation transfer difference–nuclear magnetic resonance (STD-NMR), and surface plasmon resonance (SPR). There was a moderate ground state association of HSA/HCTZ with subdomain IIA that was affected in the presence of different glucose levels. The hyperglycemic condition decreased the binding affinity of HCTZ to subdomain IIA and increased the possibility of subdomain IB also being considered as a secondary binding site due to cooperativity and/or alterations in the protein’s structure. Overall, the glucose level under hyperglycemic conditions led to the cavities being more likely to receive more ligands, offering insights into the necessity of glucose control in the human bloodstream to not impact the residence time (pharmacokinetic profile) and pharmacotherapeutic potential of HCTZ.
Understanding the resilience of social-ecological systems can advance our ability to transform environmental governance and achieve ecologically sustainable and socially just outcomes. However, ...measuring this multidimensional emergent system property has been elusive. We translated theoretical principles of resilience into ecological and social metrics and used expert knowledge to assess how they have changed through three sequential governance regimes of the Pacific herring fishery in northwestern Canada. We showed a significant reduction in system-wide resilience between previous Indigenous and historical colonial governance regimes, and limited change with the onset of the latest environmental justice era. We also detected recent signs of recovery among several metrics of resilience, thereby signaling that this system exhibits the preconditions for governance transformation. Pinpointing the erosion and recovery of attributes that confer social-ecological resilience can reveal leverage points and highlight strategic pathways to enable deliberate transformation toward a more ecologically sustainable and socially just future.
Influence of Kelp Forest Biomass on Nearshore Currents Monismith, Stephen G.; Alnajjar, Maha W.; Woodson, C. Brock ...
Journal of geophysical research. Oceans,
July 2022, 2022-07-00, 20220701, Volume:
127, Issue:
7
Journal Article
Peer reviewed
Open access
As part of a project focused on the coastal fisheries of Isla Natividad, an island on the Pacific coast of Baja California, Mexico, we conducted a 2‐1/2 year study of flows at two sites within the ...island's kelp forests. At one site (Punta Prieta), currents are tidal, whereas at the other site (Morro Prieto), currents are weaker and may be more strongly influenced by wind forcing. Satellite estimates of the biomass of the giant kelp (Macrocystis pyrifera) for this period varied between 0 (no kelp) and 3 kg/m2 (dense kelp forest), including a period in which kelp entirely was absent as a result of the 2014–2015 “Warm Blob” in the Eastern Pacific. During this natural “deforestation experiment”, alongshore velocities at both sites when kelp was present were substantially weaker than when kelp was absent, with low‐frequency alongshore currents attenuated more than higher frequency ones, behavior that was the same at both sites despite differences in forcing. The attenuation of cross‐shore flows by kelp was less than alongshore flows; thus, residence times for water inside the kelp forest, which are primarily determined by cross‐shore velocities, were only weakly affected by the presence or absence of kelp. The flow changes we observed in response to changes in kelp density are important to the biogeochemical functioning of the kelp forest in that slower flows imply longer residence times, and, are also ecologically relevant in that reduced tidal excursions may lead to more localized recruitment of planktonic larvae.
Plain Language Summary
Observations of flows were made during a two and one half year period when the state of kelp forests in the nearshore of an island off Baja California varied between lush and nonexistent. These measurements are used to show how density of kelp biomass affects currents in the nearshore of the island. Notably, the effects vary with the frequency with which the currents vary, and are much stronger for flows along the coast as opposed to cross‐shore flows that control exchange water in the kelp forest with water offshore.
Key Points
Time series of nearshore currents at two sites measured over a 30‐month period when the local kelp forests were both lush and completely absent allows direct inference of the effects of kelp biomass on local flows
Alongshore velocities at both sites when kelp was present were much weaker than when kelp was absent, with low‐frequency currents attenuated more than higher frequency ones
Because attenuation of cross‐shore flows was less than alongshore flows, residence times for water inside the kelp forest were only weakly affected by the presence or absence of kelp
The cotranslational folding is recognized as a very cooperative process that occurs after the nearly completion of the polypeptide sequence of a domain. Here we investigated the challenges faced by ...polypeptide segments of a non-vectorial β-barrel fold. Besides the biological interest behind the SARS coronavirus non-structural protein 1 (nsp1, 117 amino acids), this study model has two structural features that motivated its use in this work: 1- its recombinant production is dependent on the temperature, with greater solubility when expressed at low temperatures. This is an indication of the cotranslational guidance to the native protein conformation. 2- Conversely, nsp1 has a six-stranded, mixed parallel/antiparallel β-barrel with intricate long-range interactions, indicating it will need the full-length protein to fold properly. We used non-denaturing purification conditions that allowed the characterization of polypeptide chains of different lengths, mimicking the landscape of the cotranslational fold of a β-barrel, and avoiding the major technical hindrances of working with the nascent polypeptide bound to the ribosome. Our results showed partially folded states formed as soon as the amino acids of the second β-strand were present (55 amino acids). These partially folded states are different based on the length of polypeptide chain. The native α-helix (amino acids 24-37) was identified as a transient structure (~20-30% propensity). We identified the presence of regular secondary structure after the fourth native β-strand is present (89 amino acids), in parallel to the collapse to a non-native 3D structure. Interestingly the polypeptide sequences of the native strands β2, β3 and β4 have characteristics of α-helices. Our comprehensive analyses support the idea that incomplete polypeptide chains, such as the ones of nascent proteins much earlier than the end of the translation, adopt an abundance of specific transient folds, instead of disordered conformations.
In patients with severe traumatic brain injury (TBI), there is a lack of consensus about the need and time to perform a tracheostomy. Nowadays, the decision is individualized to each case. It is ...considered that patients that will need a tracheostomy profit by performing it earlier.
An observational and prospective study was performed. One hundred and twenty patients in a period of 18 months between 2016 and 2018, older than 18 years, with severe TBI at the first 24 h of trauma were analyzed. Clinical, biochemical, and radiological findings at admission were measured; patients were followed up until discharge. The statistical analysis was made with Student's t-test, χ2, and prevalence risk ratio.
Ten associated factors were grouped according to the prevalence risk ratio. The principal factors were CRASH score, IMPACT score, SAPS II score, APACHE II score, age, revised trauma score, Glasgow Coma Scale, subdural hematoma, uni or bilateral abnormal pupil reactivity, and collapse of basal cisterns.
We conclude that there are multiple factors associated with the need for tracheostomy in adult patients with severe TBI and it is possible to predict according to our findings from admission which patients will profit by this procedure.
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