Purification and biochemical characterization of a transglucosilating β-glucosidase of <Emphasis Type="Italic">Stachybotrys</Emphasis> strain

The filamentous fungus Stachybotrys sp has been shown to possess a rich β-glucosidase system composed of five β-glucosidases. One of them was already purified to homogeneity and characterized. In this work, a second β-glucosidase was purified and characterized. The filamentous fungal A19 strain was fed-batch cultivated on cellulose, and its extracellular cellulases (mainly β-glucosidases) were analyzed. The purified enzyme is a monomeric protein of 78 kDa molecular weight and exhibits optimal activity at pH 6.0 and at 50°C. The kinetic parameters, K _m and V _max, on para-nitro-phenyl-β-d-glucopyranosid (p-NPG) as a substrate were, respectively, 1.846 ± 0.11 mM and 211 ± 0.08 μmol min⁻¹ ml⁻¹. One interesting feature of this enzyme is its high stability in a wide range of pH from 4 to 10. Besides its aryl β-glucosidase activity towards salicin, methylumbellypheryl-β-d-glucoside (MU-Glc), and p-NPG, it showed a true β-glucosidase activity because it splits cellobiose into two glucose monomers. This enzyme has the capacity to synthesize short oligosaccharides from cellobiose as the substrate concentration reaches 30% with a recovery of 40%. We give evidences for the involvement of a transglucosylation to synthesize cellotetraose by a sequential addition of glucose to cellotriose.     

The Relationship Between Menopause and Metabolic Syndrome: Experimental and Bioinformatics Analysis

Biochemical Genetics - Menopausal hormonal changes have been associated with the emergence of the metabolic syndrome (MetS) and its consequences such as type 2 diabetes (T2D) and cardiovascular...     

Chromobacterium Csp_P Reduces Malaria and Dengue Infection in Vector Mosquitoes and Has Entomopathogenic and In Vitro Anti-pathogen Activities

Plasmodium and dengue virus, the causative agents of the two most devastating vector-borne diseases, malaria and dengue, are transmitted by the two most important mosquito vectors, Anopheles gambiae and Aedes aegypti, respectively. Insect-bacteria associations have been shown to influence vector competence for human pathogens through multi-faceted actions that include the elicitation of the insect immune system, pathogen sequestration by microbes, and bacteria-produced anti-pathogenic factors. These influences make the mosquito microbiota highly interesting from a disease control perspective. Here we present a bacterium of the genus Chromobacterium (Csp_P), which was isolated from the midgut of field-caught Aedes aegypti. Csp_P can effectively colonize the mosquito midgut when introduced through an artificial nectar meal, and it also inhibits the growth of other members of the midgut microbiota. Csp_P colonization of the midgut tissue activates mosquito immune responses, and Csp_P exposure dramatically reduces the survival of both the larval and adult stages. Ingestion of Csp_P by the mosquito significantly reduces its susceptibility to Plasmodium falciparum and dengue virus infection, thereby compromising the mosquito''s vector competence. This bacterium also exerts in vitro anti-Plasmodium and anti-dengue activities, which appear to be mediated through Csp_P -produced stable bioactive factors with transmission-blocking and therapeutic potential. The anti-pathogen and entomopathogenic properties of Csp_P render it a potential candidate for the development of malaria and dengue control strategies.     

Myenteric plexus is differentially affected by infection with distinct Trypanosoma cruzi strains in Beagle dogs

Chagasic megaoesophagus and megacolon are characterised by motor abnormalities related to enteric nervous system lesions and their development seems to be related to geographic distribution of distinct Trypanosoma cruzi subpopulations. Beagle dogs were infected with Y or Berenice-78 (Be-78) T. cruzi strains and necropsied during the acute or chronic phase of experimental disease for post mortem histopathological evaluation of the oesophagus and colon. Both strains infected the oesophagus and colon and caused an inflammatory response during the acute phase. In the chronic phase, inflammatory process was observed exclusively in the Be-78 infected animals, possibly due to a parasitism persistent only in this group. Myenteric denervation occurred during the acute phase of infection for both strains, but persisted chronically only in Be-78 infected animals. Glial cell involvement occurred earlier in animals infected with the Y strain, while animals infected with the Be-78 strain showed reduced glial fibrillary acidic protein immunoreactive area of enteric glial cells in the chronic phase. These results suggest that although both strains cause lesions in the digestive tract, the Y strain is associated with early control of the lesion, while the Be-78 strain results in progressive gut lesions in this model.     

Ellagic Acid Antiinflammatory and Antiapoptotic Potential Mediate Renoprotection in Cisplatin Nephrotoxic Rats

Ellagic acid (EA) renoprotective effect against cisplatin (CIS)‐induced nephrotoxicity remains elusive. Therefore, male Sprague–Dawley rats received CIS alone or EA (10 and 30 mg/kg, p.o.) for 5 days before and after CIS injection. CIS increased serum levels of blood urea nitrogen, creatinine, γ‐glutamyl transferase, and reduced those of albumin and total protein. It also raised serum endothelin‐1, as well as serum and renal nitric oxide, tumor necrosis factor‐α, and monocyte chemoattractant protein‐1. CIS enhanced the renal caspase‐3, hemeoxygenase (HO)‐1, nuclear factor‐κB, and inducible nitric oxide. EA hampered CIS‐induced nephrotoxicity manifested by an enhancement of the glomerular filtration rate which was associated by the reduction of inflammatory mediators and the apoptotic marker in the serum and/or kidney. The present study discloses that EA suppresses HO‐1 and, its renoprotection is also linked to its anti‐inflammatory and antiapoptotic properties, as well as the reduction of nitric oxide and endothelin‐1.     

Distribution of Carcinogenic Human Papillomavirus Genotypes and Association to Cervical Lesions among Women in Fez (Morocco)

Objectives

To determine the distribution of cervical high-risk human papillomavirus genotypes and their association to cellular abnormalities in women from Fez and its neighborhood.

Methods

Women attending the Hassan II University Hospital for cervical pap smears were recruited after an informed consent. Interviews and two cervical samples were performed for each woman. Cervical samples were used for cytological analysis and HPV DNA detection. HPV was typed using a method based on multiplex PCR with fluorescently labeled specific primers followed by capillary electrophoresis. The study was approved by the ethics committee of the Faculty of Medicine and Pharmacy of Fez.

Results

The HPV prevalence in the studied population was 43.1% and the most prevalent types were HPV 53 (23 cases); HPV 16 (20 cases); HPV 35 (18 cases); HPV 51 (10 cases) and HPV 56 (7 cases). From the 619 confirmed pap smears, 20% were abnormal. The cytological abnormalities were significantly associated to HPV infection, women age, number of pregnancies and parity (p < 0.05).

Conclusion

More attention should be given to HPV in Morocco because it represents an important public health concern. The distribution of carcinogenic HPV types in the studied population is different from the data in other regions but epidemiological studies in other Moroccan regions are required.     

Trypanosoma cruzi extracellular amastigotes selectively trigger the PI3K/Akt and Erk pathways during HeLa cell invasion

Cell invasion by Trypanosoma cruzi extracellular amastigotes involves different signaling pathways to induce phagocytosis-like mechanisms. Previous works indicated that PI3K/Akt, Src and Erk might be involved in EA invasion; however, participation of these molecules in this process remains elusive. Here, we observed that EA activated Akt, Erk but not Src. Interference of EA invasion with specific inhibitors corroborated this observation. Our results show that EA is capable of selectively triggering complex signaling pathways. Activation of PI3K/Akt and Erk, kinases related to actin cytoskeleton rearrangement and phagocytosis, reinforces the idea that T. cruzi EA subverts the phagocytic machinery during invasion.     

Research note: First report of Sporolithon ptychoides (Sporolithales,Corallinophycidae, Rhodophyta) for the Atlantic Ocean

Samples corresponding to Sporolithon ptychoides Heydrich were collected in the mesophotic zone (50 m depth) south of Espírito Santo State, Brazil. The collected material presented features characteristic of the species, namely: tetrasporangia of 75–105 × 40–55 µm grouped into sori that are raised above the surrounding vegetative thallus surface; presence of a basal layer of elongate cells in areas where the tetrasporangia develop; presence of buried tetrasporangial compartments deep in the thallus; and 3–5 cells in the tetrasporangial paraphyses. These same features said to collectively characterize S. ptychoides, were all observed in a representative specimen and the type specimen of Sporolithon dimotum (Foslie & Howe) Yamaguishi‐Tomita ex M.J Wynne. This latter species is thus conspecific with S. ptychoides and is therefore considered a heterotypic synonym thereof, as S. ptychoides has nomenclatural priority. This study expands the known geographical distribution of the species and may give insight into the origin of the species into other geographical regions.     

Thy1.2 YFP-16 Transgenic Mouse Labels a Subset of Large-Diameter Sensory Neurons that Lack TRPV1 Expression

The Thy1.2 YFP-16 mouse expresses yellow fluorescent protein (YFP) in specific subsets of peripheral and central neurons. The original characterization of this model suggested that YFP was expressed in all sensory neurons, and this model has been subsequently used to study sensory nerve structure and function. Here, we have characterized the expression of YFP in the sensory ganglia (DRG, trigeminal and vagal) of the Thy1.2 YFP-16 mouse, using biochemical, functional and anatomical analyses. Despite previous reports, we found that YFP was only expressed in approximately half of DRG and trigeminal neurons and less than 10% of vagal neurons. YFP-expression was only found in medium and large-diameter neurons that expressed neurofilament but not TRPV1. YFP-expressing neurons failed to respond to selective agonists for TRPV1, P2X_2/3 and TRPM8 channels in Ca²⁺ imaging assays. Confocal analysis of glabrous skin, hairy skin of the back and ear and skeletal muscle indicated that YFP was expressed in some peripheral terminals with structures consistent with their presumed non-nociceptive nature. In summary, the Thy1.2 YFP-16 mouse expresses robust YFP expression in only a subset of sensory neurons. But this mouse model is not suitable for the study of nociceptive nerves or the function of such nerves in pain and neuropathies.