Mitracarpus frigidus aerial parts exhibited potent antimicrobial, antileishmanial, and antioxidant effects

The crude extract and the hexane, CH(2)Cl(2), EtOAc, n-BuOH, and hydromethanolic fractions of the aerial parts of Mitracarpus frigidus were evaluated against promastigote forms of two species of Leishmania (L. chagasi and L. amazonensis), 11 strains of bacteria (Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella enterica sorovar Tythimurium, Shigella sonnei, Klebsiella pneumoniae, Escherichia coli, Micrococcus luteus, Enterococcus faecalis, Enterobacter cloacae, Streptococcus pyogenes and Bacillus cereus) and two yeasts (Candida albicans and Cryptococcus neoformans). The antioxidant activity (DPPH radical scavenging activity and reducing power), cytotoxicity against mammalian cells, and the contents of phenolics and flavonoids were determined. Phytochemical analysis of the major groups of phytoconstituents is also reported. All samples showed antioxidant activity which was positively correlated to the content of phenolic compounds. S. sonnei, B. cereus and C. neoformans were susceptible to all extracts tested, except for the n-BuOH and hydromethanolic fractions, which demonstrated no antimicrobial activity. The lowest MIC was recorded for the CH(2)Cl(2) fraction against C. neoformans (MIC of 10 microg/ml), followed by B. cereus, S. sonnei, and E. cloacae (MIC of 20, 39 and 39 microg/ml, respectively). The CH(2)Cl(2) fraction was the most effective against L. chagasi (IC(50) of 6.7 microg/ml), and the hydromethanolic fraction exhibited the best activity against L. amazonensis (IC(50) of 9 microg/ml). A cytotoxic effect on mammalian cells was observed only for the crude extract and CH(2)Cl(2) fraction at the concentrations of 130 and 31 microg/ml, respectively. These results suggest that M. frigidus has interesting antimicrobial, antileishmanial and antioxidant activities.     

Structural analysis of gellans produced by Sphingomonas elodea strains by electrospray tandem mass spectrometry

A commercial gellan sample (Gelrite) and a gellan-like polymer (JB3) obtained by exposure of the producing strain to chemical mutagenesis were subjected to partial acid hydrolysis and the resultant oligosaccharides were identified by Electrospray Mass Spectrometry (ESI-MS) and Tandem Mass Spectrometry (ESI-MS/MS and MSⁿ). In both gellans, the main fragments were in accordance with the tetrasaccharide repeating unit, d-Glucose (Glc)-d-Glucuronic acid (GlcA)-d-Glucose (Glc)-l-Rhamose (Rha), described for the wild-type gellan, showing the higher acid lability of the Rha-(1 → 3)-Glc linkage when compared to the (1 → 4) of the other residues. Under the experimental conditions used in the study, as expected, no acyl substituents were observed in the commercial gellan but in JB3 oligosaccharides a glyceryl moiety was identified, substituted in the 3-linked Glc residue. Furthermore, the analysis of the MS/MS and MSⁿ spectra of both gellans allowed the identification of structural details, some of them not yet reported for these exopolysaccharides. The presence of oligosaccharides with single Glc and Rha residues substituent of the tetrasaccharide unit of gellan may represent novel side chains of the backbone unit that to our knowledge have never been reported previously for the gellan exopolysaccharide.     

Depth as an overarching environmental variable modulating preservation potential and temporal resolution of shelly taphofacies

In the marine realm, the interpretation of taphofacies relies heavily on how oceanographic and sedimentary conditions affect the preservation state of fossils. Several taphonomic variables either covary with depth or are directly influenced by depth. Facies‐level factors rather than broad, basin‐scale parameters influence the taphonomic profile of mollusc death assemblages according to actualistic and experimental evidence. To determine the possible relation between depth and the taphonomic conditions of multiple species of bivalve remains, we used seven samples gathered over a comprehensive bathymetric gradient (from 7 to 150 m below mean sea level; topmost 10‐ to 20‐cm layer, roughly corresponding to the taphonomically active zone). We selected samples from predominantly muddy facies on the southern Brazilian shelf (SBS). The taphonomic damage profile (TDP) was measured using site samples based on a standard taphonomic analysis (categorical scoring system) of shells and fragments larger than 4 mm, to identify site damage patterns. Restricting the sedimentary grain size (samples from fine sediments) enabled the determination of the variation in damage with depth among the samples. Constrained analysis of proximities (CAP) revealed that up to 46% of the taphonomic variation observed was related to variation in depth (with approximately 28% unexplained by environmental factors). Part of the unexplained fraction was due to the effect of temporal mixing, which is predictable along large‐scale patches but is inversely linked to the TDP. Our results show that taphonomic analysis, considering large spatial scales in recent environments, can explain the variations present in shell beds that formed during distinct time periods of the evolution of a Quaternary sedimentary basin.     

Acanthoscurria gomesiana spider-derived Mygalin in the prelimbic prefrontal cortex modulates neuropathic pain and depression comorbid

Depression has a high rate of comorbidity with neuropathic pain. This study aims to investigate the effect of Mygalin, an acylpolyamine synthesized from a natural molecule in the hemolymph of the Acanthoscurria gomesiana spider, injected into the prelimbic (PrL) region of the medial prefrontal cortex on chronic neuropathic pain and depression comorbidity in rats. To investigate that comorbidity, neuropathic pain was induced by chronic constriction injury (CCI) of the sciatic nerve in male Wistar rats. The biotinylated biodextran amine (BDA) bidirectional neural tract tracer was microinjected into the PrL cortex to study brain connections. Rodents were further subjected to von Frey (mechanical allodynia), acetone (cold allodynia), and forced swim (depressive-like behavior) tests. BDA neural tract tracer-labeled perikarya were found in the dorsal columns of the periaqueductal gray matter (dPAG) and the dorsal raphe nucleus (DRN). Neuronal activity of DRN neurons decreased in CCI rats. However, PrL cortex treatment with Mygalin increased the number of spikes on DRN neurons. Mygalin treatment in the PrL cortex decreased both mechanical and cold allodynia and immobility behavior in CCI rats. PrL cortex treatment with N-methyl-D -aspartate (NMDA) receptor receptors attenuated the analgesic and antidepressive effects caused by Mygalin. The PrL cortex is connected with the dPAG and DRN, and Mygalin administration into the PrL increased the activity of DRN neurons. Mygalin in the PrL cortex produced antinociceptive and antidepressive-like effects, and the NMDA agonist reversed these effects.     

Insulin resistance is improved in high‐fat fed mice by photobiomodulation therapy at 630 nm

Photobiomodulation therapy (PBMT) in the infrared spectrum exerts positive effects on glucose metabolism, but the use of PBMT at the red spectrum has not been assessed. Male Swiss albino mice were divided into low‐fat control and high‐fat diet (HFD) for 12 weeks and were treated with red (630 nm) PBMT or no treatment (Sham) during weeks 9 to 12. PBMT was delivered at 31.19 J/cm², 60 J total dose per day for 20 days. In HFD‐fed mice, PBMT improved glucose tolerance, insulin resistance and fasting hyperinsulinemia. PBMT also reduced adiposity and inflammatory infiltrate in adipose tissue. Phosphorylation of Akt in epididymal adipose tissue and rectus femoralis muscle was improved by PBMT. In epididymal fat PBMT reversed the reduced phosphorylation of AS160 and the reduced Glut4 content. In addition, PBMT reversed the alterations caused by HFD in rectus femoralis muscle on proteins involved in mitochondrial dynamics and β‐oxidation. In conclusion, PBMT at red spectrum improved insulin resistance and glucose metabolism in HFD‐fed mice.      

Salivary β-glucosidase as a direct factor influencing the occurrence of halitosis

β-Glucosidases are enzymes present in all living organisms, playing a pivotal role in diverse biological processes. These enzymes cleave β-glycosidic bonds between carbohydrates, or between a carbohydrate and a non-carbohydrate moiety, which may result in the liberation of volatile aglycones. Released compounds execute diverse physiological roles, while the industry takes advantage of exogenously added β-glucosidases for aroma enrichment during food and beverage production. β-Glucosidase enzymatic activity has been reported in human saliva and given the fact that these enzymes are involved in aroma release, we investigated here the correlation between β-glucosidase activity in human saliva and the occurrence of halitosis. Measurement of salivary enzyme activity of 48 volunteers was performed using p-nitrophenyl-β-d-glucopyranoside as substrate. Each volunteer was clinically evaluated by a dental surgeon and clinical and laboratorial data were statistically analyzed. Gas-chromatography of saliva headspace allowed the analysis of the direct role of exogenous β-glucosidase on aromatic /volatile profile of saliva samples. The data demonstrated a positive correlation between halitosis and enzymatic activity, suggesting that the enzyme exerts a direct role in the occurrence of bad breath. Gas-chromatography analysis demonstrated that exogenously added enzyme led to the alteration of volatile organic content, confirming a direct contribution of β-glucosidase activity on saliva volatile compounds release. Although halitosis is a multifactorial condition, the complete understanding of all governing factors may allow the development of more effective treatment strategies. Such studies may pave the way to the use of β-glucosidase inhibitors for halitosis clinical management.     

Plagiarism of the host immune system: lessons about chemokine immunology from viruses

In their attempts to evade the host immune response, mammalian viruses have evolved a wide range of strategies. These include the expression and modification of various host cytokines and receptors. Understanding the mechanism of action of these virally encoded proteins will clearly deepen our insights into immunology. In the past few months several new virally encoded chemokines have been described which can modify both the host immune and antiviral response. Their manipulation of the cytokine structure-function relationship may also be useful in the development of reagents for treating immune and proliferative diseases.