Data-based approach for time-correlated closures of turbulence models.

Developed turbulent motion of fluid still lacks an analytical description despite more than a century of active research. Nowadays, phenomenological ideas are widely used in practical applications, such as small-scale closures for numerical simulations of turbulent flows. In the present paper, we use a shell model of turbulence to construct a closure intended to have a solid theoretical background and to capture intrinsic probabilistic features of turbulence. Shell models of turbulence are dynamical deterministic systems used to model energy cascade and other key aspects of the Navier-Stokes such as intermittency. We rescale the variables of the Sabra model in a way which leads to hidden symmetries and universal distributions. We then use such fine distributions to write closures, i.e., missing expressions for some of the Sabra variables. Our closures rely on approximating probability density functions using a Gaussian mixture model, which makes them probabilistic by nature and allows us to write time-correlated closures. We also provide a framework where other machine learning tools can be employed with reduced black-box aspects.

Evaluation of the antimicrobial activity of Eucalyptus radiata essential oil against Escherichia coli strains isolated from meat products.

The present study sought to evaluate the antimicrobial and anti-adherent potential of Eucalyptus radiata essential oil against food-borne strains of Escherichia coli. The study was performed using the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC). In addition, the disk diffusion technique was used to evaluate the association of Eucalyptus radiata essential oil with synthetic antimicrobials. The Minimum Inhibitory Adherence Concentration (MIC) was also performed. The results revealed that E. radiata showed antimicrobial activity against the E. coli strains tested, with MIC values ranging from 500 µg/mL to 1000 µg/mL and MBC values ranging from 500 µg/mL to 1,024 µg/mL. As for the associations, it was observed that E. radiata oil exhibited a synergistic effect for some antibiotics, especially Ceftriaxone, with greater interference from the essential oil. Furthermore, it was effective in inhibiting the adherence of bacterial strains of E. coli, showing a more significant antibiofilm effect than the antibacterial agent 0.12% chlorhexidine digluconate. In summary, the essential oil of E. radiata showed antimicrobial potential against strains of E. coli of food origin, and can therefore, through in-depth studies, be used alone or in association with synthetic antimicrobials to combat infections caused by this pathogen.

Oral squamous cell carcinoma arising from areas of Graft-versus-host disease: A systematic review.

BACKGROUND: Graft-versus-host disease (GVHD) is an immune system reaction that occurs in patients with a history of hematopoietic stem cell transplantation (HSCT), in which the grafted donor's cells attack those of the host. The objective of this systematic review was to present a study on oral squamous cell carcinoma (OSSC) that developed from GVHD areas in patients undergoing HSCT. MATERIAL AND METHODS: An electronic search was conducted in the databases PUBMED, WEB OF SCIENCE, SCOPUS, MEDLINE and SCIENCE DIRECT, according to PRISMA guidelines. RESULTS: Of the 1582 results, 23 articles were included, resulting in 81 cases. The most common underlying disease for performing the transplant was Myeloid Leukemia (55.6%). The mean age was 39 years, with a predilection for males (64.2%). The tongue was the site of GVHD that most frequently underwent transformation to SCC (59.3%). The average time between transplantation and the development of GVHD was of approximately of 8 months, while the average period of development between transplantation and the development of OSCC was of approximately of 111 months. The most common treatment to GVHD was cyclosporine associated with corticosteroids. CONCLUSIONS: OSCCs arising from areas of GVHD present a different evolution from conventional oral carcinomas, since they affect younger patients, smoking and alcohol are not important etiological factors and finally because they present good prognosis, but further studies with larger number cases followed are needed to confirm our findings.

Oral amyloidosis: an update.

BACKGROUND: Amyloidosis is a disease characterized by the progressive deposition of abnormal proteins that can occur in any organ. In the oral cavity, the tongue is the most common affected site, usually causing macroglossia. Biopsy is essential for the diagnosis and the occurrence of its systemic form is mandatory to be investigated. This systematic review evaluated the existing information in the literature on Amyloidosis in the oral cavity to allow a more comprehensive and updated analysis of its clinicopathological characteristics, as well as to explore the main forms of treatment and prognostic factors. MATERIAL AND METHODS: Electronic searches were undertaken in five databases supplemented by manual scrutiny. RESULTS: A total of 111 studies were included with 158 individuals. CONCLUSIONS: The disease had a higher prevalence in women, the tongue was the most affected site, as well as the systemic form of the disease. The worst prognosis was for cases of systemic amyloidosis associated with multiple myeloma.

Association of Candida albicans and Cbp+ Streptococcus mutans with early childhood caries recurrence.

Early childhood caries (ECC) recurrence occurs in approximately 40% of treated cases within one year. The association of Streptococcus mutans and Candida albicans with the onset of ECC is well known. Also, S. mutans strains harboring collagen-binding proteins (Cbps) avidly bind to collagen-rich dentin and are linked to increased caries risk. Here, we investigated the presence of Cbp+ S. mutans and C. albicans in saliva and dental plaque of children with varying caries statuses, and their salivary microbiome. In this cross-sectional study, 143 children who were caries-free (n = 73), treated for ECC with no signs of recurrence after 6 months (n = 45), or treated for ECC and experiencing recurrence within 6 months following treatment (n = 25) were enrolled. Co-infection with C. albicans and S. mutans, especially Cbp+ S. mutans, was strongly associated with caries recurrence. Subjects of the recurrence group infected with Cbp+ S. mutans showed a greater burden of Candida spp. and of Mutans streptococci in dentin than those infected with Cbp- strains. Salivary microbiome analysis revealed that Streptococcus parasanguinis was overrepresented in the caries recurrence group. Our findings indicate that Cbp+ S. mutans and C. albicans are intimately associated with caries recurrence, contributing to the establishment of recalcitrant biofilms.

Zinc import mediated by AdcABC is critical for colonization of the dental biofilm by Streptococcus mutans in an animal model.

Trace metals are essential to all domains of life but toxic when found at high concentrations. Although the importance of iron in host-pathogen interactions is firmly established, contemporary studies indicate that other trace metals, including manganese and zinc, are also critical to the infectious process. In this study, we sought to identify and characterize the zinc uptake system(s) of Streptococcus mutans, a keystone pathogen in dental caries and a causative agent of bacterial endocarditis. Different than other pathogenic bacteria, including several streptococci, that encode multiple zinc import systems, bioinformatic analysis indicated that the S. mutans core genome encodes a single, highly conserved, zinc importer commonly known as AdcABC. Inactivation of the genes coding for the metal-binding AdcA (ΔadcA) or both AdcC ATPase and AdcB permease (ΔadcCB) severely impaired the ability of S. mutans to grow under zinc-depleted conditions. Intracellular metal quantifications revealed that both mutants accumulated less zinc when grown in the presence of a subinhibitory concentration of a zinc-specific chelator. Notably, the ΔadcCB strain displayed a severe colonization defect in a rat oral infection model. Both Δadc strains were hypersensitive to high concentrations of manganese, showed reduced peroxide tolerance, and formed less biofilm in sucrose-containing media when cultivated in the presence of the lowest amount of zinc that support their growth, but not when zinc was supplied in excess. Collectively, this study identifies AdcABC as the major high affinity zinc importer of S. mutans and provides preliminary evidence that zinc is a growth-limiting factor within the dental biofilm.

Influence of dietary Chlorella vulgaris and carbohydrate-active enzymes on growth performance, meat quality and lipid composition of broiler chickens.

Herein, we investigated the effect of Chlorella vulgaris as ingredient (10% of incorporation) in broiler diets, supplemented or not with 2 formulations of Carbohydrate-Active enZymes (CAZymes; Rovabio Excel AP and a mixture of recombinant CAZymes, composed by an exo-ß-glucosaminidase, an alginate lyase, a peptidoglycan N-acetylmuramic acid deacetylase and a lysozyme), on growth performance, meat quality, fatty acid composition, oxidative stability, and sensory traits. One hundred twenty 1-day-old Ross 308 male birds were randomly assigned to one of the 4 experimental diets (n = 30): corn-soybean meal-basal diet (control), basal diet with 10% C. vulgaris (CV), CV supplemented with 0.005% of a commercial CAZyme cocktail (Rovabio Excel AP), (CV + R), and CV supplemented with 0.01% of a 4-CAZyme mixture previously selected (CV + M) during the experimental period lasted from day 21 to day 35. Body weight gain and feed conversion rate of broilers were not affected by C. vulgaris but digesta viscosity increased more than 2-fold (P < 0.001) relative to the control. In addition, neither cooking loss, shear force, juiciness, flavor nor off-flavor was impaired by dietary treatments (P > 0.05). By contrast, the dietary C. vulgaris increased tenderness, yellowness (b∗) and total carotenoids in breast and thigh meats. However, no additional protective effect against lipid oxidation was observed in meat with the inclusion of microalga. Chlorella vulgaris, independently of CAZymes, had a minor impact on meat fatty acid composition but improved the proportion of some beneficial fatty acids. In summary, our data indicate a slight improvement of broiler meat quality and lipid nutritional value, without impairment of broilers' growth performance, thus supporting the usefulness of this microalga in poultry diets, up to this high level of incorporation. By contrast, the selected CAZyme mixtures used do not significantly improve the release of microalga nutrients in poultry diets, through the disruption of microalga cell wall, which warrants further research.

Impact of dietary incorporation of Spirulina (Arthrospira platensis) and exogenous enzymes on broiler performance, carcass traits, and meat quality.

This study assessed the effect of Spirulina (Arthrospira platensis), individually and in combination with exogenous enzymes, on growth performance, carcass traits, and meat quality of broiler chickens. One hundred and twenty Ross 308 male chickens were allocated into 40 battery brooders, with 3 birds per cage, and fed ad libitum a corn-based diet during the first 21 D of the trial. The experimental period lasted from day 21 to 35, during which birds were fed 4 different diets: a corn-soybean basal diet, taken as the control group, a basal diet containing 15% Spirulina (MA), a basal diet containing 15% Spirulina plus 0.005% Rovabio Excel AP (MAR), and a basal diet containing 15% Spirulina plus 0.01% lysozyme (MAL). Body weight gain (P < 0.001) and feed conversion rate (P < 0.001) were improved in control chickens, when compared with those fed with Spirulina. In addition, Spirulina increased the length of duodenum plus jejunum in relation to the other treatment (P < 0.01). Chickens on the MAL diet showed a considerable increase in digesta viscosity (P < 0.05) compared with the control group. Breast and thigh meats from chickens fed with Spirulina, with or without the addition of exogenous enzymes, had higher values of yellowness (b*) (P < 0.001), total carotenoids (P < 0.001), and saturated fatty acids (P < 0.001), whereas n-3 polyunsaturated fatty acid (P < 0.01) and α-tocopherol (P < 0.001) decreased, when compared with the control. In conclusion, the incorporation of 15% Spirulina in broiler diets, individually or combined with exogenous enzymes, reduced birds' performance through a higher digesta viscosity, which is likely associated with the gelation of microalga indigestible proteins. In addition, cell wall of Spirulina was successfully broken by the addition of lysozyme, but not by Rovabio Excel AP. Therefore, we anticipate that the combination of lysozyme with an exogenous specific peptidase could improve the digestibility of proteins from this microalga and avoid their detrimental gelation.

Clinical-pathological and sociodemographic factors associated with the distant metastasis and overall survival of oral cavity and oropharynx squamous cell carcinoma.

BACKGROUND: The objective of this study was to evaluate the influence of clinical-pathological and sociodemographic factors on the prevalence of distant metastasis (DM) and overall survival in patients with oral cavity and oropharynx squamous cell carcinoma (OOSCC). MATERIAL AND METHODS: Cross-sectional study based on the records of 404 OOSCC patients evaluated for DM, covering the period 2000-2014. We analysed the influence of age, sex, level of schooling, primary tumor subsite, treatment, marital status, family history of cancer, history of smoking and alcohol consumption, type of health care coverage (private vs. public) and overall survival. Findings were submitted to Fisher's exact test, Pearson's chi-squared test, Mantel-Cox log-rank testing and multinomial and Cox regression analysis (SPSS v. 20.0; p<0.05). RESULTS: The prevalence of DM was 5.4% (22/404). The respiratory tract was the most affected DM site (n=9; 40.9%). Male sex (p=0.049), oropharyngeal primary tumor (p=0.008), stage T3-4 (p=0.022), lymph node metastasis (N+) (p<0.001) and palliative treatment (p=0.005) were directly associated with DM. Patients with oral primary tumours (p=0.343) and primary oropharyngeal tumours (p=0.242) did not differ significantly with regard to the prevalence of DM. N+ was an independent risk factor for DM (p=0.017). Five variables independently reduced overall survival: male sex (p=0.035), age >65 years (p=0.046), indigenous/brown racial type (p=0.045), palliative treatment (p=0.035) and DM (p=0.048). CONCLUSIONS: Lymph node metastasis independently increased the prevalence of DM and, along with male sex, older age, brown racial type and palliative treatment, was independently associated with poor prognosis in patients with OOSCC.

Utility of stent double palliation for esophageal cancer with airway involvement: the extremis of care.

Primary esophageal cancer (EC) frequently presents as a locally advanced disease with airway involvement. Placement of combined esophageal and airway stents has been reported in small series to be an effective palliation strategy. Our aims are to present the largest cohort of EC patients who underwent double stent palliation and to evaluate the safety and efficacy of this approach. Longitudinal cohort study of patients with primary EC undergoing two-stage esophageal and airway stent placement at an oncology referral institute (January 2000-January 2019). Assessments: baseline demographics and clinical variables; baseline and week 2 dysphagia, dyspnea and performance status (PS) scores; baseline and week 8 body mass index (BMI); overall survival. Statistics: paired t-test; Kaplan-Meier method. Seventy patients (89% men, mean age 60.20 ± 8.41) underwent double stenting. Esophageal stent was placed for esophageal stenosis and dysphagia (n = 41; placement of a second stent due to recurrence in nine cases) or esophagorespiratory fistulas (ERFs) (n = 29); airway stent was required for ERF sealing (n = 29 + 7 new ERFs after esophageal stent) and to ensure airway patency due to malignant stenosis (n = 29; placement of a second stent due to recurrence in 13 cases) or compression (n = 5). There were 13, endoscopically managed, major complications after esophageal stent [hemorrage (n = 1), migration (n = 5) and new fistulas (n = 7)]. As for airway stents, four major complications were recorded [hemorrage (n = 1) and three deaths due to respiratory infection and ultimately respiratory failure 3-7 days after the procedure]. Overall, patients showed significant improvement in dysphagia and dyspnea symptoms (3.21 vs. 1.31 e 15.56 vs. 10.87; P < 0.001). There was a PS improvement for 89.2% (n = 58) of the patients. BMI at week 8 was comparable to baseline records. Mean survival was 137.83 ± 24.14 days (95% CI: 90.51-185.15). Survival was longer for better PS (PS1, 249.95 days; PS2, 83.74 days; PS3, 22.43 days; PS4, 30.00 days). This is the largest comprehensive assessment of double stent palliation in advanced incurable EC. For both esophageal or airway stenosis and fistula, placement of combined esophageal and airway stents was a feasible, effective, fast-acting and safe modality for symptom palliation and body mass maintenance. Patient autonomy followed symptom improvement. Since it is impossible to provide treatment for cure in most of these cases, this endoscopic strategy, performed in differentiated units with the required technical capacity, may guarantee treatment for the relief of palliative EC.

(p)ppGpp and CodY Promote Enterococcus faecalis Virulence in a Murine Model of Catheter-Associated Urinary Tract Infection.

In Firmicutes, the nutrient-sensing regulators (p)ppGpp, the effector molecule of the stringent response, and CodY work in tandem to maintain bacterial fitness during infection. Here, we tested (p)ppGpp and codY mutant strains of Enterococcus faecalis in a catheter-associated urinary tract infection (CAUTI) mouse model and used global transcriptional analysis to investigate the relationship of (p)ppGpp and CodY. The absence of (p)ppGpp or single inactivation of codY led to lower bacterial loads in catheterized bladders and diminished biofilm formation on fibrinogen-coated surfaces under in vitro and in vivo conditions. Single inactivation of the bifunctional (p)ppGpp synthetase/hydrolase rel did not affect virulence, supporting previous evidence that the association of (p)ppGpp with enterococcal virulence is not dependent on the activation of the stringent response. Inactivation of codY in the (p)ppGpp0 strain restored E. faecalis virulence in the CAUTI model as well as the ability to form biofilms in vitro Transcriptome analysis revealed that inactivation of codY restores, for the most part, the dysregulated metabolism of (p)ppGpp0 cells. While a clear linkage between (p)ppGpp and CodY with expression of virulence factors could not be established, targeted transcriptional analysis indicates that a possible association between (p)ppGpp and c-di-AMP signaling pathways in response to the conditions found in the bladder may play a role in enterococcal CAUTI. Collectively, data from this study identify the (p)ppGpp-CodY network as an important contributor to enterococcal virulence in catheterized mouse bladder and support that basal (p)ppGpp pools and CodY promote virulence through maintenance of a balanced metabolism under adverse conditions.IMPORTANCE Catheter-associated urinary tract infections (CAUTIs) are one of the most frequent types of infection found in the hospital setting that can develop into serious and potentially fatal bloodstream infections. One of the infectious agents that frequently causes complicated CAUTI is the bacterium Enterococcus faecalis, a leading cause of hospital-acquired infections that are often difficult to treat due to the exceptional multidrug resistance of some isolates. Understanding the mechanisms by which E. faecalis causes CAUTI will aid in the discovery of new druggable targets to treat these infections. In this study, we report the importance of two nutrient-sensing bacterial regulators, named (p)ppGpp and CodY, for the ability of E. faecalis to infect the catheterized bladder of mice.

Technetium-99m-labeled lapachol as an imaging probe for breast tumor identification. / Lapachol marcado con tecnecio 99m como sonda de imágenes para la identificación de tumores de mama.

OBJECTIVE: Breast cancer is a health problem worldwide with high incidence and mortality rates. It is well known that the development of more sensitive and specific diagnostic methods is of great importance since an early diagnosis is essential to successfully treat tumors. Lapachol is a natural compound, belonging to the naphthoquinone group that has been widely used in traditional medicine to treat various illnesses, including cancer. The aim of this study was to evaluate technetium-99m (99mTc) labeled lapachol as an imaging probe for breast cancer identification. METHODS: To achieve this purpose, lapachol was labeled with 99mTc, radiochemical purity and in vitro stability were determined. Blood clearance, in healthy mice, and biodistribution, in 4T1 tumor-bearing mice, were also evaluated. RESULTS: Lapachol was successfully labeled with 99mTc, with high values of radiochemical yield (95.9±3.4%). In vitro stability showed that the radiolabeled complex remained stable for up to 24h, with values above 90% for both saline and plasma (95.6±3.6% and 96.4±1.7%, respectively). The radiolabeled complex decays in a biphasic manner, with a half-life of distribution and elimination equal to 3.3 and 50.0min, respectively. Biodistribution and scintigraphic images showed high uptake in organs of excretion (kidneys, liver, and intestine). It could be also noted that tumor uptake was higher than the muscle at all time points. Tumor-to-muscle ratio reaches ∼4.5 at 24h after administration. CONCLUSION: These findings suggest that 99mTc-lapachol can be a potential diagnostic agent for breast tumors.

The impact of glycemic variability on length of stay and mortality in diabetic patients admitted with community-acquired pneumonia or chronic obstructive pulmonary disease.

AIM: To investigate the influence of glycemic variability (GV) on length of stay and in-hospital mortality in non-critical diabetic patients. METHODS: A observation retrospective study was performed. Diabetic patients admitted between January and June 2016 with the diagnosis of community-acquire pneumonia (CAP) and/or acute exacerbation of chronic obstructive pulmonary disease (COPD) were enrolled and glycemic control (persistent hyperglycemia, hypoglycemia, mean glucose level (MGL) and respective standard deviation (SD) and coefficient of variation (CV)) were evaluated. Primary outcomes were length of stay and in-hospital mortality. RESULTS: Data from 242 patients were analyzed. Fifty-eight percent of the patients were male, with a median age of 77 years (min-max, 29-98). Patients had on average 2.1 glucose readings-day and the MGL was 193.3 mg/dl (min-max, 84.3-436.6). Hypoglycemia was documented in 13.4% of the patients and 55.4% had persistent hyperglycemia. The median length of hospital stay was 10 days (min-max, 1-66) and in-hospital mortality was 7.4%. We found a significant higher in-hospital mortality in older patients, with history of cancer and with nosocomial infections. We did not find any correlation between MGL, SD, CV, hypoglycemia or persist hyperglycemia and in-hospital mortality. A longer length of stay was observed in patients with heavy alcohol consumption and nosocomial infections. The length of stay was negatively correlated with the mean glucose level (r2-0.147; p < 0.05) and positively correlated with the coefficient of variation (p 0.162; p < 0.05). CONCLUSION: This study confirmed the negative impact of the glycemic variability in the outcomes of diabetic patients admitted with CAP or acute exacerbation of COPD.

The Biology of Streptococcus mutans.

As a major etiological agent of human dental caries, Streptococcus mutans resides primarily in biofilms that form on the tooth surfaces, also known as dental plaque. In addition to caries, S. mutans is responsible for cases of infective endocarditis with a subset of strains being indirectly implicated with the onset of additional extraoral pathologies. During the past 4 decades, functional studies of S. mutans have focused on understanding the molecular mechanisms the organism employs to form robust biofilms on tooth surfaces, to rapidly metabolize a wide variety of carbohydrates obtained from the host diet, and to survive numerous (and frequent) environmental challenges encountered in oral biofilms. In these areas of research, S. mutans has served as a model organism for ground-breaking new discoveries that have, at times, challenged long-standing dogmas based on bacterial paradigms such as Escherichia coli and Bacillus subtilis. In addition to sections dedicated to carbohydrate metabolism, biofilm formation, and stress responses, this article discusses newer developments in S. mutans biology research, namely, how S. mutans interspecies and cross-kingdom interactions dictate the development and pathogenic potential of oral biofilms and how next-generation sequencing technologies have led to a much better understanding of the physiology and diversity of S. mutans as a species.

Biology of Oral Streptococci.

Bacteria belonging to the genus Streptococcus are the first inhabitants of the oral cavity, which can be acquired right after birth and thus play an important role in the assembly of the oral microbiota. In this article, we discuss the different oral environments inhabited by streptococci and the species that occupy each niche. Special attention is given to the taxonomy of Streptococcus, because this genus is now divided into eight distinct groups, and oral species are found in six of them. Oral streptococci produce an arsenal of adhesive molecules that allow them to efficiently colonize different tissues in the mouth. Also, they have a remarkable ability to metabolize carbohydrates via fermentation, thereby generating acids as byproducts. Excessive acidification of the oral environment by aciduric species such as Streptococcus mutans is directly associated with the development of dental caries. However, less acid-tolerant species such as Streptococcus salivarius and Streptococcus gordonii produce large amounts of alkali, displaying an important role in the acid-base physiology of the oral cavity. Another important characteristic of certain oral streptococci is their ability to generate hydrogen peroxide that can inhibit the growth of S. mutans. Thus, oral streptococci can also be beneficial to the host by producing molecules that are inhibitory to pathogenic species. Lastly, commensal and pathogenic streptococci residing in the oral cavity can eventually gain access to the bloodstream and cause systemic infections such as infective endocarditis.

Effects of calcium and sodium on ATP-induced vasopressin release from rat isolated neurohypophysial terminals.

ATP-receptors (P2X2, P2X3, P2X4 & P2X7) are found in neurohypophysial terminals (NHT). These purinergic receptor subtypes are known to be cation selective. Here we confirm that both sodium (Na+ ) and calcium (Ca2+ ) are permeable through these NHT purinergic receptors, but to varying degrees (91% vs. 9%, respectively). Furthermore, extracellular calcium inhibits the ATP-current magnitude. Thus, the objective of this study was to determine the effects of extracellular Na+ vs. Ca2+ on ATP-induced vasopressin (AVP) release from populations of rat isolated NHT. ATP (200 µM) perfused exogenously for 2 minutes in Normal Locke's buffer caused an initial transient increase in AVP release followed by a sustained increase in AVP release which lasted for the duration of the ATP exposure. Replacing extracellular NaCl with NMDG-Cl had no apparent effect on the ATP-induced transient increase in AVP release but abolished the sustained AVP release induced by ATP. Furthermore, removal of extracellular calcium resulted in no ATP-induced transient increase in AVP release, but had no effect on the delayed, sustained increase in AVP release. The ATP-induced calcium-dependent transient increase in AVP release was >95% inhibited by 10 µM of the P2X purinergic receptor antagonist PPADS, a dose sufficient to block P2X2 and P2X3 receptors but not P2X4 or P2X7 receptors. Interestingly, the ATP-induced calcium-independent, sodium-dependent sustained increase in AVP release was not affected by 10 µM PPADS. The ATP-induced calcium-dependent transient increase in AVP release was not affected by the P2X7 receptor antagonist BBG (100 nM). However, the ATP-induced sodium-dependent sustained AVP release was inhibited by 50%. Therefore, these results show that rat isolated NHT exhibit a biphasic response to exogenous ATP that is differentially dependent on extracellular calcium and sodium. Furthermore, the initial transient release appears to be through P2X2 and/or P2X3 receptors and the sustained release is through a P2X7 receptor. This article is protected by copyright. All rights reserved.

Whole genome sequence and phenotypic characterization of a Cbm+ serotype e strain of Streptococcus mutans.

We report the whole genome sequence of the serotype e Cbm+ strain LAR01 of Streptococcus mutans, a dental pathogen frequently associated with extra-oral infections. The LAR01 genome is a single circular chromosome of 2.1 Mb with a GC content of 36.96%. The genome contains 15 phosphotransferase system gene clusters, seven cell wall-anchored (LPxTG) proteins, all genes required for the development of natural competence and genes coding for mutacins VI and K8. Interestingly, the cbm gene is genetically linked to a putative type VII secretion system that has been found in Mycobacteria and few other Gram-positive bacteria. When compared with the UA159 type strain, phenotypic characterization of LAR01 revealed increased biofilm formation in the presence of either glucose or sucrose but similar abilities to withstand acid and oxidative stresses. LAR01 was unable to inhibit the growth of Strpetococcus gordonii, which is consistent with the genomic data that indicate absence of mutacins that can kill mitis streptococci. On the other hand, LAR01 effectively inhibited growth of other S. mutans strains, suggesting that it may be specialized to outcompete strains from its own species. In vitro and in vivo studies using mutational and heterologous expression approaches revealed that Cbm is a virulence factor of S. mutans by mediating binding to extracellular matrix proteins and intracellular invasion. Collectively, the whole genome sequence analysis and phenotypic characterization of LAR01 provides new insights on the virulence properties of S. mutans and grants further opportunities to understand the genomic fluidity of this important human pathogen.

Abundance and spatial-temporal distribution of Macrobrachium surinamicum Holthuis, 1948 (Palaemonidae) in the Amazon estuary, north of Brazil / Abundância e distribuição espaço-temporal de Macrobrachium surinamicum Holthuis, 1948 (Palaemonidae) em um estuário Amazônico, norte do Brasil

Abstract Macrobrachium surinamicum is a small shrimp that inhabits rivers of low salinity. It is mainly caught as bycatch in Amazon shrimp Macrobrachium amazonicum fisheries, which is widely exploited by artisanal fisheries for food and economic needs of the riverside population. This study aimed to characterize the spatial and temporal distribution of the freshwater shrimp M. surinamicum in the Guajará Bay and on Mosqueiro Island, correlating the abundance of this species with abiotic factors (temperature and salinity). Samples were taken from May 2006 to April 2007 in six locations: Mosqueiro Island (Furo das Marinhas and Porto do Pelé); Icoaraci district; Arapiranga Island, edge of the city of Belém; and Combu Island, using traps named 'matapis'. A total of 361 shrimps were caught. The abundance was higher in December and lower in July 2006. The biggest catch occurred on Arapiranga Island and the lowest on Mosqueiro Island. The abundance differed significantly in December 2006 and no variable studied had significant influence on M. surinamicum abundance. In Guajará Bay, particularly the more sheltered places, as Arapiranga and Combu islands, favor the development of M. surinamicum, indicating that this species has preference for less disturbed areas.

Resumo Macrobrachium surinamicum é um camarão de pequeno porte que habita a foz de rios e águas de baixa salinidade. Sua captura na Amazônia ocorre principalmente como fauna associada à pesca do camarão-da-Amazônia Macrobrachium amazonicum que é largamente explorado pela pesca artesanal atendendo as necessidades alimentícias e econômicas da comunidade ribeirinha. O presente estudo teve como objetivo caracterizar a distribuição espaço-temporal do camarão dulcícola M. surinamicum na Baía do Guajará e Ilha de Mosqueiro, correlacionando a abundância desta espécie com fatores abióticos (temperatura e salinidade). Os exemplares foram capturados no período de maio/06 a abril/07 em seis locais: Ilha de Mosqueiro (Furo das Marinhas e Porto do Pelé), Distrito de Icoaraci, Ilha do Arapiranga, orla de Belém e Ilha do Combu com armadilhas (matapis). Um total de 361 camarões foi capturado, sendo a maior abundância em dezembro e a menor em julho de 2006. A maior captura foi na Ilha de Arapiranga e a menor na Ilha de Mosqueiro. A abundância diferiu significativamente em dezembro/06 e nenhuma variável estudada teve influência significativa na abundância de M. surinamicum. A Baía do Guajará, especialmente os locais mais abrigados como a Ilha de Arapiranga e do Combu, propiciam o desenvolvimento de M. surinamicum, o que indica que esta espécie tenha preferência para áreas menos antropizadas.

Ecophysiological interactions and water-related physicochemical parameters among freshwater stingrays / Interações ecofisiológicas e dos parâmetros físico-químico da água em arraias de água doce

Abstract The objective of this study was to compare and correlate the ecology of neonates and young individuals of Potamotrygon wallacei, Potamotrygon motoro and Paratrygon aiereba with regard to their hematological profile and the physicochemical parameters of the water that they inhabit. Principal component analysis (PCA) on the complete blood count revealed total variation of 72.92%, thus demonstrating a differentiation system for oxygen demand. On the other hand, P. motoro was considered to be an intermediate species, given that its complete blood count characteristics interacted with both P. wallacei and with P. aiereba. The interaction among the biochemical variables was shown to total 64.67% of the factors. This allowed differentiation of P. wallacei from P. aiereba, while P. motoro maintained an intermediate position. These characteristics of differentiation within the preferred environment corroborate the PCA of the present study and confirm that these species can be differentiated through considering the complete blood count and biochemical parameters. The PCA on water properties showed 68.57% differentiation, mainly comprising the x axis (49.44%). It can be affirmed that P. motoro has the capacity to inhabit the preferential areas of P. wallacei and P. aiereba, as well as occupying localities in which other stingrays are not found. In conclusion, P. wallacei presents patterns differentiating it from P. aiereba, while P. motoro is a species that presents intermediate characteristics. The latter can be considered to be a more broadly distributed species regarding its ecophysiological characteristics.

Resumo Este trabalho tem por objetivo investigar o perfil hematológico e os parâmetros físico-químicos da água, comparando e correlacionando ecologicamente entre neonatos e jovens de Potamotrygon wallacei (arraia cururu), Potamotrygon motoro e Paratrygon aiereba. A análise de componentes principais (PCA) do hemograma revelou um total 72,92% de variação, constituindo-se em um sistema de diferenciação na demanda por oxigênio. P. wallacei apresenta diferenciação no eixo X quando comparada a P. aiereba, por outro lado P. motoro constitui-se como uma espécie intermediária que apresenta as características do hemograma interagindo tanto com P. wallacei quanto com P. aiereba. A interação entre as variáveis bioquímica demonstram um total de 64,67% dos fatores, no qual foi possível diferenciar, a arraia P. wallacei de P. aiereba, tendo P. motoro uma aspecto de espécie intermediária entre as demais. Esses aspectos de diferenciação de ambiente de preferência corroboraram a PCA obtida no presente estudo e confirmam que essas espécies podem ser diferenciadas quando se considerar as variáveis referentes ao hemograma e a bioquímica. Nos íons, no trombograma e no leucograma, não foi possível diferenciar as espécies. O PCA das propriedades da água foi constituído por 68,57% de diferenciação que se constituiu principalmente no eixo x (49,44%). É possível confirmar que P. motoro tem a capacidade de habitar as áreas preferências de P. wallacei e P. aiereba, além do mais esta possui uma localidade que as demais arraias não são encontradas. Conclui-se que P. wallacei, apresenta padrões diferenciados de P. aiereba, além do mais P. motoro é uma espécie que apresenta características intermediárias entre as descritas, o qual pode ser considerado uma espécie com distribuição mais ampla em seus aspectos ecofisiológicos.