CRISPRals: A Web Database for Assessing the CRISPR Defense System in the Ralstonia solanacearum Species Complex to Avoid Phage Resistance.

Clustered regularly interspaced short palindromic repeats (CRISPR) has been widely characterized as a defense system against phages and other invading elements in bacteria and archaea. A low percentage of Ralstonia solanacearum species complex (RSSC) strains possess the CRISPR array and the CRISPR-associated proteins (Cas) that would confer immunity against various phages. To provide a wide-range screen of the CRISPR presence in the RSSC, we analyzed 378 genomes of RSSC strains to find the CRISPR locus. We found that 20.1, 14.3, and 54.5% of the R. solanacearum, R. pseudosolanacearum, and R. syzygii strains, respectively, possess the CRISPR locus. In addition, we performed further analysis to identify the respective phages that are restricted by the CRISPR arrays. We found 252 different phages infecting different strains of the RSSC, by means of the identification of similarities between the protospacers in phages and spacers in bacteria. We compiled this information in a database with web access called CRISPRals (https://crisprals.yachaytech.edu.ec/). Additionally, we made available a number of tools to detect and identify CRISPR array and Cas genes in genomic sequences that could be uploaded by users. Finally, a matching tool to relate bacteria spacer with phage protospacer sequences is available. CRISPRals is a valuable resource for the scientific community that contributes to the study of bacteria-phage interaction and a starting point that will help to design efficient phage therapy strategies.

Intraoperative Ultrasound: Real-Time Surgical Adjunct for Complete Resection of Spinal Arachnoid Webs.

Spinal arachnoid webs are abnormal formations of arachnoid membranes that reside in the arachnoid space. Clinically, they may present as an incidental finding or in patients with progressively worsening myelopathy. Early detection and surgical intervention are recommended in patients with progressive symptoms. Several methods have been described for the surgical treatment of these web formations.1-4 The success of surgery and the ability to prevent recurrence is dependent on complete surgical resection of these lesions, which in some cases can appear complex and intricate in nature. A few reports have highlighted the use of intraoperative ultrasound to localize the lesion; however, none have highlighted its value in establishing successful web resection and restoration of normal cerebrospinal fluid flow.3,4 Herein, we demonstrate the use of intraoperative ultrasound as an effective adjunct to assessing and establishing complete resection of arachnoid webs. We illustrate how intraoperative ultrasound allows for real-time, direct visualization of arachnoid lysis with restoration of normal cerebrospinal fluid flow (Video 1). Our patient was symptomatic for 12 months with rapid progression of myelopathic symptoms in the 3 months before presentation. Following surgery, she remained asymptomatic at 4-year follow-up with no reoccurrence at 24-month magnetic resonance imaging. Intraoperative ultrasound is a useful adjunct to successfully performing dorsal arachnoid web surgery and ensuring improved surgical outcomes through complete web resection and decompression of the spinal cord.

Potential Role for Stem Cell Regenerative Therapy as a Treatment for Degenerative Disc Disease and Low Back Pain: A Systematic Review.

Back pain is the single leading cause of disability worldwide. Despite the prevalence and morbidity of lower back pain, we still lack a gold-standard treatment that restores the physiological function of degenerated intervertebral discs. Recently, stem cells have emerged as a promising strategy for regenerative therapy for degenerative disc disease. In this study, we review the etiology, pathogenesis, and developing treatment strategies for disc degeneration in low back pain with a focus on regenerative stem cell therapies. A systematic search of PubMed/MEDLINE/Embase/Clinical Trials.gov databases was conducted for all human subject abstracts or studies. There was a total of 10 abstracts and 11 clinical studies (1 RCT) that met the inclusion criteria. The molecular mechanism, approach, and progress of the different stem cell strategies in all studies are discussed, including allogenic bone marrow, allogenic discogenic cells, autologous bone marrow, adipose mesenchymal stem cells (MSCs), human umbilical cord MSC, adult juvenile chondrocytes, autologous disc derived chondrocytes, and withdrawn studies. Clinical success with animal model studies is promising; however, the clinical outcomes of stem cell regenerative therapy remain poorly understood. In this systematic review, we found no evidence to support its use in humans. Further studies on efficacy, safety, and optimal patient selection will establish whether this becomes a viable, non-invasive therapeutic option for back pain.

Pressure control cam displacement in the Codman-Hakim programmable valve after a 3T MRI: Case report and review of the literature.

Pressure control cam dislocation is a rare finding in patients with a programmable shunt valve that should be considered when evaluating patients with signs and symptoms of shunt malfunction. The objective of this paper is to review the mechanism, clinical presentation, and radiographic findings associated with pressure control cam (PCC) dislocation, in addition to presenting a novel case to add to the scarce literature on this topic. A systematic review of the literature were performed using PubMed, Embase, and Cochrane from database inception. PCC dislocation is exceedingly rare and can present with no symptoms, positional headache, neck pain, nausea, or vomiting. Skull x-ray findings demonstrate a clear black "X" at the distal end of the valve, due to the PCC disarticulation from atop the base plate of the plastic valve housing. Intraoperatively, a "Y"-shaped crack atop the plastic valve housing may be present and the PCC may be fully separated from the shunt or found at the distal end of the plastic valve housing. Prior reports of dislocation of the PCC have occurred 7-9 years after implantation, with inciting events including direct trauma, programmable valve adjustment, and utilization 3-Tesla magnetic resonance image scan.

Management of United Airway Disease Focused on Patients With Asthma and Chronic Rhinosinusitis With Nasal Polyps: A Systematic Review.

BACKGROUND: The clinical approach to upper and lower respiratory diseases from a joint perspective, known as united airways disease (UAD), is challenging for health care professionals owing to a paucity of specific studies. OBJECTIVE: This study reviews recent scientific evidence on the management of asthma and chronic rhinosinusitis with nasal polyps (CRSwNP) from a UAD perspective. METHODS: A systematic search of PubMed, Scopus, and Web of Science was conducted for 9 research questions, and studies published from January 2015 to July 2021 were included. Quality assessment was performed with the Critical Appraisal Skills Programme. RESULTS: In total, 32 publications met the inclusion criteria. Control of type 2 inflammation in UAD (reported in 9 studies) was associated with biologic therapies, for which an impact on asthma, CRSwNP, and/or aspirin/nonsteroidal anti-inflammatory drug-exacerbated respiratory disease outcomes was described in 9 studies. However, there was a lack of scientific evidence on clinical and/or biochemical markers associated with response to biologics in patients with UAD. The benefit on corticosteroid reduction in patients receiving biologics was reported in 9 studies. Three publications reported a positive impact of surgery on asthma and/or CRSwNP outcomes, and the effect of biologics on reducing the need of surgery was consistent across 6 studies. CONCLUSIONS: Our results underscore an overall scarcity of scientific evidence on the treatment strategies for these frequent coexisting entities from an UAD approach but also identify several research gaps and unmet needs that should be addressed to ensure optimal diagnosis, management, and follow-up of these patients.

The importance of previous season performance on world-class 200- and 400-m individual medley swimming.

We examined the degree to which 200-m and 400-m Individual Medley (IM) performance was related to sprint-, middle- and long-distance events before a swimmer reached a Top-20 world ranking. A retrospective longitudinal modelling study was conducted. Data on Top-20 swimmers between 2010 and 2018 were obtained from publicly available websites. A general linear model was used to examine associations between 200-m and 400-mIM performance (FINA ranking points) and performance in sprint, middle-distance and distance events in the previous two years. In the 200-mIM, there were significant associations (p < 0.001) between prior competition results obtained for both the 200-mIM (r = 0.80; ß = 0.543) and 400-m IM (r = 0.70; ß = 0.317) events before the Top-20 performance in 200-mIM in the year of the Top-20. Sprint distance events were associated (p < 0.006; r = 0.39; ß = 0.088) with 200-mIM (t). Each additional 10 FINA points in the 200-mIM in each of the two years preceding the Top-20 performance. were associated with an increase of 5 FINA points in 200-mIM in in the year of the Top-20 (goodness of fit R 2 = 0.70). There were similar associations (p < 0.001) for a Top 20-FINA 400-mIM performance with both 200-mIM (r = 0.72; ß = 0.385) and 400-m IM (r = 0.79; ß = 0.492) events in the two years before a swimmer reached the Top-20. Middle-distance events were associated with 400-mIM performance (p < 0.001; r = 0.53; ß = 0.163). Each additional 10 FINA points in 400-mIM in in each of the two years preceding the Top-20 performance were associated with an increase of 5 FINA points in in the year that a swimmer reached the Top-20 (goodness of fit R 2 = 0.75). The specificity and complexity of the IM require a thorough preparation in this event for world-class performances. The 200-mIM is more closely related to sprint distance events, whereas middle-distance events support preparations for the 400-mIM.

Evaluating the real-life effect of MP-AzeFlu on asthma outcomes in patients with allergic rhinitis and asthma in UK primary care.

BACKGROUND: MP-AzeFlu (Dymista®; spray of azelastine/fluticasone propionate) is the most effective allergic rhinitis (AR) treatment available. Its effect on asthma outcomes in patients with AR and asthma is unknown. METHODS: This pre-post historical cohort study, using the Optimum Patient Care Research Database, included patients aged ≥12 years, from UK general practice with active asthma (defined as a recorded diagnosis, with ≥1 prescription for reliever or controller inhaler) in the year before or at the initiation date. The primary study outcome was change in number of acute respiratory events (i.e. exacerbation or antibiotic course for a respiratory event) between baseline and outcome years. The effect size of MP-AzeFlu was quantified as the difference in % of patients that improved and worsened. RESULTS: Of the 1,188 patients with AR and asthma included, many had a record of irreversible obstruction (67%), and uncontrolled asthma (70.4%), despite high mean daily doses of reliever/controller therapy and acute oral corticosteroid use, in the year pre-MP-AzeFlu initiation. MP-AzeFlu initiation was associated with fewer acute respiratory events (effect size (e) = 5.8%, p = 0.0129) and a reduction in daily use of short-acting ß2-agonists, with fewer patients requiring >2 SABA puffs/week (e = 7.7% p < 0.0001). More patients had well-controlled asthma 1-year post-MP-AzeFlu initiation (e = 4.1%; p = 0.0037), despite a reduction in inhaled corticosteroids (e = 4.8%; p = 0.0078). CONCLUSIONS: This study provides the first direct evidence of the beneficial effect of MP-AzeFlu on asthma outcomes in co-morbid patients in primary care in the United Kingdom. TRIAL REGISTRATION: EUPAS30940. Registered August 13, 2019.

Diversity and evolutionary dynamics of spore-coat proteins in spore-forming species of Bacillales.

Among members of the Bacillales order, there are several species capable of forming a structure called an endospore. Endospores enable bacteria to survive under unfavourable growth conditions and germinate when environmental conditions are favourable again. Spore-coat proteins are found in a multilayered proteinaceous structure encasing the spore core and the cortex. They are involved in coat assembly, cortex synthesis and germination. Here, we aimed to determine the diversity and evolutionary processes that have influenced spore-coat genes in various spore-forming species of Bacillales using an in silico approach. For this, we used sequence similarity searching algorithms to determine the diversity of coat genes across 161 genomes of Bacillales. The results suggest that among Bacillales, there is a well-conserved core genome, composed mainly by morphogenetic coat proteins and spore-coat proteins involved in germination. However, some spore-coat proteins are taxa-specific. The best-conserved genes among different species may promote adaptation to changeable environmental conditions. Because most of the Bacillus species harbour complete or almost complete sets of spore-coat genes, we focused on this genus in greater depth. Phylogenetic reconstruction revealed eight monophyletic groups in the Bacillus genus, of which three are newly discovered. We estimated the selection pressures acting over spore-coat genes in these monophyletic groups using classical and modern approaches and detected horizontal gene transfer (HGT) events, which have been further confirmed by scanning the genomes to find traces of insertion sequences. Although most of the genes are under purifying selection, there are several cases with individual sites evolving under positive selection. Finally, the HGT results confirm that sporulation is an ancestral feature in Bacillus.

Diversity and Evolutionary Dynamics of Antiphage Defense Systems in Ralstonia solanacearum Species Complex.

Over the years, many researchers have reported a great diversity of bacteriophages infecting members of the Ralstonia solanacearum species complex (RSSC). This diversity has driven bacterial evolution by leading the emergence and maintenance of bacterial defense systems to combat phage infection. In this work, we present an in silico study of the arsenal of defense systems that RSSC harbors and their evolutionary history. For this purpose, we used a combination of genomic, phylogenetic and associative methods. We found that in addition to the CRISPR-Cas system already reported, there are eight other antiphage defense systems including the well-known Restriction-Modification and Toxin-Antitoxin systems. Furthermore, we found a tenth defense system, which is dedicated to reducing the incidence of plasmid transformation in bacteria. We undertook an analysis of the gene gain and loss patterns of the defense systems in 15 genomes of RSSC. Results indicate that the dynamics are inclined toward the gain of defense genes as opposed to the rest of the genes that were preferably lost throughout evolution. This was confirmed by evidence on independent gene acquisition that has occurred by profuse horizontal transfer. The mutation and recombination rates were calculated as a proxy of evolutionary rates. Again, genes encoding the defense systems follow different rates of evolution respect to the rest of the genes. These results lead us to conclude that the evolution of RSSC defense systems is highly dynamic and responds to a different evolutionary regime than the rest of the genes in the genomes of RSSC.

New Onset British Accent, Acute Behavioral Changes, and Seizures: A Unique Presentation of NMDAR Encephalitis.

The leading cause of autoimmune encephalitis is N-methyl-D-aspartate receptor (NMDAR) encephalitis. Symptoms can present as prominent behavioral abnormalities prompting inaccurate psychiatric diagnoses. Psychiatric features such as bizarre behavior, agitation, anxiety, delusions, and hallucinations are well noted in the current literature, but a manifestation of foreign accent syndrome has, to our knowledge, never been reported in cases of encephalitis. Once diagnosed, initiation of therapy can result in effective treatment. Here, we present a case of a 32-year-old female with new onset seizures and marked behavioral changes, such as speaking in a foreign accent, who was empirically treated for NMDAR encephalitis due to strong clinical suspicion, showed no improvement with first line therapy with IVIG and IV steroids, and finally had rapid resolution of symptoms with the early initiation of second line therapy of rituximab. In a young female presenting with nonspecific behavioral changes, NMDAR encephalitis should be on the differential and, although CSF antibodies are definitively diagnostic, there should be a low threshold to start empiric therapy and escalate to second line treatment.

Rare Case of Anti-LGI1 Limbic Encephalitis with New Onset Epilepsy: A Case Report.

Anti-leucine-rich glioma-inactivated 1 (LGI1) limbic encephalitis (LE) has been classified as an autoimmune LE with a subacute course. Many patients with anti-LGI1 LE have normal or minimal cerebrospinal fluid (CSF) findings. Cerebrospinal fluid 14-3-3 protein or neuron specific enolase is usually seen in Creutzfeldt-Jakob disease (CJD) with high sensitivities, but can also be positive in other paraneoplastic and autoimmune encephalitides, which can make diagnosis challenging. The mainstay of treatment for anti-LGI1 LE generally focuses on steroids, intravenous immunoglobulin (IVIG), plasmapheresis, and/or rituximab. All the aforementioned modalities can be used in the treatment of anti-LGI1 LE and since this condition is highly responsive to treatment with steroids, prompt diagnosis can help stall the progression of this disease. Here, we present a case of anti-LGI1 LE that initially improved with empiric immunotherapy and showed definitive return to baseline with initiation of rituximab.

A genome-wide scan for genes under balancing selection in the plant pathogen Ralstonia solanacearum.

BACKGROUND: Plant pathogens are under significant selective pressure by the plant host. Consequently, they are expected to have adapted to this condition or contribute to evading plant defenses. In order to acquire long-term fitness, plant bacterial pathogens are usually forced to maintain advantageous genetic diversity in populations. This strategy ensures that different alleles in the pathogen's gene pool are maintained in a population at frequencies larger than expected under neutral evolution. This selective process, known as balancing selection, is the subject of this work in the context of a common bacterial phytopathogen. We performed a genome-wide scan of Ralstonia solanacearum species complex, an aggressive plant bacterial pathogen that shows broad host range and causes a devastating disease called 'bacterial wilt'. RESULTS: Using a sliding window approach, we analyzed 57 genomes from three phylotypes of the R. solanacearum species complex to detect signatures of balancing selection. A total of 161 windows showed extreme values in three summary statistics of population genetics: Tajima's D, θw and Fu & Li's D*. We discarded any confounding effects due to demographic events by means of coalescent simulations of genetic data. The prospective windows correspond to 78 genes with known function that map in any of the two main replicons (1.7% of total number of genes). The candidate genes under balancing selection are related to primary metabolism and other basal activities (51.3%) or directly associated to virulence (48.7%), the latter being involved in key functions targeted to dismantle plant defenses or to participate in critical stages in the pathogenic process. CONCLUSIONS: We identified various genes under balancing selection that play a significant role in basic metabolism as well as in virulence of the R. solanacearum species complex. These genes are useful to understand and monitor the evolution of bacterial pathogen populations and emerge as potential candidates for future treatments to induce specific plant immune responses.

Ultrastructural analysis of spores from diverse Bacillales species isolated from Brazilian soil.

Many species in the order Bacillales form a specialized cell type called a spore that is resistant to a range of environmental stresses. Transmission electron microscopy (TEM) reveals that the spore is comprised of a series of concentric shells, surrounding an interior compartment harbouring the spore DNA. The outermost of these shells varies considerably in morphology among species, likely reflecting adaptations to the highly diverse niches in which spores are found. To better characterize the variation in spore ultrastructure among diverse species, we used TEM to analyse spores from a collection of 23 aerobic spore-forming bacteria from the Solo do Distrito Federal (SDF strains), spanning the genera Bacillus, Lysinibacillus, Paenibacillus and Brevibacillus, isolated from soil from central Brazil. We found that the structures of these spores varied widely, as expected. Interestingly, even though these isolates are novel strains of each species, they were structurally very similar to the known examples of each species in the literature. Because in most cases, the species we analysed are poorly characterized, our data provide important evidence regarding which structural features are likely to be constant within a taxon and which are likely to vary.

Influence of Light on Plant-Phyllosphere Interaction.

Plant-phyllosphere interactions depend on microbial diversity, the plant host and environmental factors. Light is perceived by plants and by microorganisms and is used as a cue for their interaction. Photoreceptors respond to narrow-bandwidth wavelengths and activate specific internal responses. Light-induced plant responses include changes in hormonal levels, production of secondary metabolites, and release of volatile compounds, which ultimately influence plant-phyllosphere interactions. On the other hand, microorganisms contribute making some essential elements (N, P, and Fe) biologically available for plants and producing growth regulators that promote plant growth and fitness. Therefore, light directly or indirectly influences plant-microbe interactions. The usage of light-emitting diodes in plant growth facilities is helping increasing knowledge in the field. This progress will help define light recipes to optimize outputs on plant-phyllosphere communications. This review describes research advancements on light-regulated plant-phyllosphere interactions. The effects of full light spectra and narrow bandwidth-wavelengths from UV to far-red light are discussed.

Construct Validity of the Portuguese Version of the Wagnild and Young Resilience Scale.

BACKGROUND AND PURPOSE: This study aims to validate the resilience scale developed by Wagnild and Young for the Portuguese population. METHODS: The instrument validation was conducted with a sample of 313 adults attending the Higher Institute of Educational Sciences, of which 62.3% were female and 37.7% male, between 18 and 58 years old. RESULTS: Three factors were decided upon: life satisfaction, planning-discipline, and independence, and there was a positive average correlation between the three factors. The confirmatory factor analysis showed excellent comparative fit index and root mean square error of approximation values, so we conclude that the model has an excellent fit. Also, Cronbach's alpha coefficient used for internal consistency values reported good values. CONCLUSIONS: Overall, the key global indicators of the model's fit and reliability analysis express their quality for Portuguese population.

Efectividad del tratamiento y seguimiento longitudinal de pacientes con TLP tratados en Hospital de Día / The effectfiveness of the treatment and the longitudinal follow-up of the BPD patients, treated at the Day Hospital / Efectivitat del tractament i seguiment longitudinal de pacients amb TLP tractats en un hospital de dia

El objetivo de este estudio es evaluar la gravedad sintomatologica y el funcionamiento social en una muestra de 35 pacientes que habían sido derivados al Programa TLP (trastorno límite de la personalidad) de un Hospital de Día. La evaluación del cambio clínico, realizada mediante la escala de Impresión Clínica Global (ICG-TLP), puso de manifiesto que los pacientes mejoran tras el tratamiento en ocho de las 10 áreas típicas del trastorno y mantienen esta mejoría a los cinco años de seguimiento, excepto en impulsividad y afectividad. Los resultados muestran que el tratamiento especializado para el TLP en Hospitales de Día es beneficioso para los pacientes que lo sufren

The objective of this study is to evaluate the symptom severity and the social functioning in a sample of 35 patients who had been derived to BPD (borderline personality disorder) (TLP) Programme of a Day Hospital. The evaluation of a clinical change, performed using the Global Clinical Impression scale (ICG-BPD), showed that patients improved after treatment in 8 of the 10 typical areas of the disorder and that they maintained this improvement after five years of follow-up, except in impulsivity and affectivity. The results show that the specialized treatment for BPD in Day Hospitals is beneficial for patients suffering from BPD

L'objectiu d'aquest estudfi és avaluar fla gravetat simptomatològfica i el funcionament social en una mostra de 35 pacients que havien estat derivats afl Programa TLP (trastorn límfit de la personalitat) d'un hospfitafl de dfia. L'avaluacfió defl canvi clínfic, realitzada mitjançant l'escafla d'Impressió Clínica Global (ICG-TLP), posà de manifest que els pacients milloren després del tractament en vufit de fles 10 àrees típiques del trastorn i mantenen aquesta milloria als cinc anys de seguiment, excepte en impulsivitat i afectivitat. Es resultats mostren que el tractament especialitzat pel TLP en hospitals de dia és beneficiós per als pacients que el pateixe

Relações entre suporte social, autorregulação e consumo de outras substâncias em adultos portugueses

Neste estudo, investigaram-se as relações entre suporte social percebido, auto-regulação e comportamentos de consumo de álcool, tabaco e outras substâncias psicoactivas. A amostra foi constituída por 340 participantes. O suporte social correlacionou-se favoravelmente com a auto-regulação, mas somente na vertente de satisfação com o apoio social é que se observou esta tendência de forma evidente. O número de figuras de apoio diferenciou-se significativamente com o uso de tabaco, o que sugere o âmbito afiliativo de algumas substâncias psicoactivas. Nesse sentido, o uso de tabaco pode estar associado a uma rede social mais ampla, mas não com a qualidade do suporte social.

In this study the relationships between perceived social support, self-regulation and consuming behaviors of tobacco and other psychoactive substances we investigated. The sample consisted of 340 adult participants. Social support correlated positively with self-regulation, but was solely in the aspect of satisfaction with social support that this trend was noted clearly. The number of support providers differed considerably with the use of tobacco, which suggests the affiliative scope of some psychoactive substances. Accordingly, the use of tobacco may be associated with a larger social network, but not with the quality of social support.

Distribución espacial y estructura morfométrica de las praderas de Thalassia testudinum (Hydrocharitaceae) en dos arrecifes del Parque Nacional Sistema Arrecifal Veracruzano, México / Spatial distribution and ecological structure of Thalassia testudinum (Hydrocharitaceae) in two reefs of Veracruz Reef System National Park, Mexico

ResumenLos pastos marinos son ambientes costeros que se han visto amenazados por el incremento de las actividades humanas. Alterando de forma negativa los procesos y servicios ambientales que presentan, así como la disminución de praderas. El objetivo es generar conocimiento de la distribución, estado de la estructura y nivel de fragmentación en dos arrecifes del Parque Nacional Sistema Arrecifal Veracruzano (PNSAV). Se eligieron dos praderas en arrecifes con características distintas: Sacrificios en el Norte que se encuentra cerca de la costa y Cabezo en el Sur que está alejado de la costa. Se determinaron las características específicas de haz y área de las praderas de macrófitas sumergidas presentes e identificaron cuatro grupos de cobertura morfofuncionales. Se comprobaron diferencias significativas entre coberturas (ANOVA no paramétrico, prueba de Kruskal-Wallis). Se realizó una clasificación supervisada de una imagen espacial de alta resolución verificada con datos de campo (55 Sacrificios y 290 Cabezo). El nivel de fragmentación se calculó usando métricas de paisaje a nivel de clase y se realizaron mapas temáticos en función de las cuatro coberturas. Las praderas se encuentran dominadas por Thalassia testudinum; se tuvieron densidades máximas de 208 haces/m2 para Cabezo y 176 haces/m2 en Sacrificios. Cabezo presentó pastos de hojas cortas (9 cm) y delgadas (0.55 cm) en promedio; Sacrificios tuvo hojas más largas (23.5 cm) y gruesas (1 cm). Sacrificios mostró menor grado de fragmentación que Cabezo; en ambos casos la fragmentación de la cobertura vegetal corresponde a menos del 50 %. Aunque el arrecife Cabezo presenta una mayor fragmentación, que crea un gran número de microambientes, siendo reconocido por su importancia como zona de reclutamiento. Este trabajo sirve como una línea de base para la creación de un plan de manejo adecuado (formación de una zona núcleo de Cabezo). Es necesario complementar este trabajo con nuevos esfuerzos del reconocimiento de las praderas de pastos marinos en todos los arrecifes del PNSAV, así como de monitoreos periódicos y reconocimiento de sus servicios ecosistémicos.

AbstractSeagrasses in coastal environments have been threatened by increased human activities; these have negatively altered processes and environmental services, and have decreased grassland areas. The aim of this study was to generate knowledge of Thalassia testudinum distribution, state of the structure and fragmentation level in two reefs of the Veracruz Reef System National Park (PNSAV). Two different reefs were selected: Sacrificios in the North and near the coast, and Cabezo in the South and away from the coast. Shoot-specific and area-specific characteristics of submerged macrophytes meadows present were determined, and four morpho-functional groups were identified. Significant differences between plant coverage were tested through nonparametric ANOVA, Kruskal-Wallis test. A supervised classification of spatial high-resolution image verified with field data was performed (55 Sacrificios and 290 Cabezo). The fragmentation level was calculated using landscape metrics, class level and thematic maps were made based on four covers. The meadows were dominated by Thalassia testudinum; maximum densities were 208 shoot/m2 in Cabezo, and 176 shoot/m2 in Sacrificios. Cabezo presented grasses with short (9 cm) and thin leaves (0.55 cm) on average; while Sacrificios showed longer (23.5 cm) and thicker (1 cm) leaves. Sacrificios showed lower fragmentation degree than Cabezo; in both cases, the vegetation cover fragmentation corresponded to less than 50 %. Although Cabezo reef presents further fragmentation, which creates a large number of microenvironments, being recognized for its importance as recruitment area. This work serves as a baseline for the creation of an adequate management plan (formation of a core area of Cabezo). It is necessary to complement this work with new efforts for the recognition of seagrass prairies in all PNSAV reefs, as well as periodic monitoring and recognition of ecosystem services. Rev. Biol. Trop. 64 (2): 427-448. Epub 2016 June 01.

Gating the glutamate gate of CLC-2 chloride channel by pore occupancy.

CLC-2 channels are dimeric double-barreled chloride channels that open in response to hyperpolarization. Hyperpolarization activates protopore gates that independently regulate the permeability of the pore in each subunit and the common gate that affects the permeability through both pores. CLC-2 channels lack classic transmembrane voltage-sensing domains; instead, their protopore gates (residing within the pore and each formed by the side chain of a glutamate residue) open under repulsion by permeant intracellular anions or protonation by extracellular H(+). Here, we show that voltage-dependent gating of CLC-2: (a) is facilitated when permeant anions (Cl(-), Br(-), SCN(-), and I(-)) are present in the cytosolic side; (b) happens with poorly permeant anions fluoride, glutamate, gluconate, and methanesulfonate present in the cytosolic side; (c) depends on pore occupancy by permeant and poorly permeant anions; (d) is strongly facilitated by multi-ion occupancy; (e) is absent under likely protonation conditions (pHe = 5.5 or 6.5) in cells dialyzed with acetate (an impermeant anion); and (f) was the same at intracellular pH 7.3 and 4.2; and (g) is observed in both whole-cell and inside-out patches exposed to increasing [Cl(-)]i under unlikely protonation conditions (pHe = 10). Thus, based on our results we propose that hyperpolarization activates CLC-2 mainly by driving intracellular anions into the channel pores, and that protonation by extracellular H(+) plays a minor role in dislodging the glutamate gate.

[Spatial distribution and ecological structure of Thalassia testudinum (Hydrocharitaceae) in two reefs of Veracruz Reef System National Park, Mexico]. / Distribución espacial y estructura morfométrica de las praderas de Thalassia testudinum (Hydrocharitaceae) en dos arrecifes del Parque Nacional Sistema Arrecifal Veracruzano, México.

Seagrasses in coastal environments have been threatened by increased human activities; these have negatively altered processes and environmental services, and have decreased grassland areas. The aim of this study was to generate knowledge of Thalassia testudinum distribution, state of the structure and fragmentation level in two reefs of the Veracruz Reef System National Park (PNSAV). Two different reefs were selected: Sacrificios in the North and near the coast, and Cabezo in the South and away from the coast. Shoot-specific and area-specific characteristics of submerged macrophytes meadows present were determined, and four morpho-functional groups were identified. Significant differences between plant coverage were tested through nonparametric ANOVA, Kruskal-Wallis test. A supervised classification of spatial high-resolution image verified with field data was performed (55 Sacrificios and 290 Cabezo). The fragmentation level was calculated using landscape metrics, class level and thematic maps were made based on four covers. The meadows were dominated by Thalassia testudinum; maximum densities were 208 shoot/m2 in Cabezo, and 176 shoot/m2 in Sacrificios. Cabezo presented grasses with short (9 cm) and thin leaves (0.55 cm) on average; while Sacrificios showed longer (23.5 cm) and thicker (1 cm) leaves. Sacrificios showed lower fragmentation degree than Cabezo; in both cases, the vegetation cover fragmentation corresponded to less than 50 %. Although Cabezo reef presents further fragmentation, which creates a large number of microenvironments, being recognized for its importance as recruitment area. This work serves as a baseline for the creation of an adequate management plan (formation of a core area of Cabezo). It is necessary to complement this work with new efforts for the recognition of seagrass prairies in all PNSAV reefs, as well as periodic monitoring and recognition of ecosystem services. .