Isolation of Cellulolytic Actinomycetes from Marine Sediments

The cellulolytic activity of 36 actinomycetes strains isolated from marine sediments was investigated by the cellulose-azure method. Approximately 50% of the isolates exhibited various degrees of cellulolytic activity.     

Asn-linked oligosaccharide-dependent interaction between laminin and gp120/140. An alpha 6/beta 1 integrin

Receptor-mediated recognition and adhesion to laminin, a specific glycoprotein from basement membranes, exert an important role in many biological phenomena. Studying cell surface proteins of B16-F10, a metastatic murine melanoma cell line, we identified a 120-140 kDa glycoprotein (gp120/140) that binds laminin. This glycoprotein was recognized by a polyclonal antibody raised against the human fibronectin receptor beta 1-integrin chain, as well as immunoprecipitated by an anti-alpha 6 chain (monoclonal antibody GoH3), characterizing it as an alpha 6/beta 1-integrin. Its binding to laminin was specific and displayed moderate affinity, as its apparent dissociation constant was 18 nM. To characterize the influence of carbohydrate moieties on the laminin-gp120/140 interaction, metaperiodate oxidation, metabolic inhibition of glycosylation, and enzymatic deglycosylation studies were performed. Our results indicate that gp120/140 Asn-linked oligosaccharides play a part in this interaction. Reciprocally, both metaperiodate and N-glycanase treatment of native laminin reduced its binding to gp120/140, characterizing the latter as a lectin-like molecule. These results point to glycosylation processes as a possible mechanism for variable binding specificity profiles among integrins.     

Food habits and the survival and growth of nestlings in two sympatric kites (Milvus milvus and Milvus migrans)

A comparative study of the Red Kite and Black Kite was conducted in the Doana National Park in southwestern Spain. Although the diets of both kites were similar, the Red Kite captured significantly more prey items from scrub habitats close to nesting areas than from marsh habitats, which were further away. Habitat differences in prey abundance and distance from breeding areas suggest that the Red Kite depended on a less abundant but more stable food supply. Nestling mortality from starvation was highest for the last hatched nestlings in both species. The growth rate of Black Kite nestlings was markedly higher than that of Red Kite nestlings. Moreover, growth rates increased with clutch size in the Red Kite, whereas they were constant in the Black Kite. Differences between species in reproductive traits are discussed mainly with regard to their feeding ecology. The slower growth and greater effect of sibling asymmetry on mortality of the Red Kite are consistent with our interpretation that the Red Kite's food supply is less abundant than the Black Kite's.     

Neuronal maturation in an experimental model of brain tissue heterotopia in the lung

Neural maturation involves diverse interaction and signaling mechanisms that are essential to the development of the nervous system. However, little is known about the development of neurons in heterotopic brain tissue in the lung, a rare abnormality observed in malformed babies and fetuses. The aim of this study was to identify the neurons and to investigate their maturation in experimental brain tissue heterotopia during fetal and neonatal periods. The fetuses from 24 pregnant female Swiss mice were used to induce brain tissue heterotopia on the 15th gestational day. Briefly, the brain of one fetus of each dam was extracted, disaggregated, and injected into the right hemithorax of siblings. Six of these fetuses with pulmonary brain tissue implantation were collected on the 18th gestational day (group E18), and six others were collected on the 8th postnatal day (group P8). The brain of each fetus from dams not submitted to any experimental procedure was collected on the 18th gestational day (group CE18) and on the 8th postnatal day (group CP8) to serve as a control for neuronal quantitation and maturation. Immunohistochemical staining of NeuN was used to assess neuron quantity and maturation. The NeuN labeling index was greater in the postnatal period than in the fetal period for the experimental and control groups (P8 > E18 and CP8 > CE18), although there were fewer neurons in experimental than in control groups (P8 < CP8 and E18 < CE18) (P < 0.005). These results indicate that fetal neuroblasts/neurons not only survive a dramatic event such as mechanical disaggregation, in the same way as it happens in human cases, but also they retain their development in heterotopia, irrespective of local tissue influences.     

Physical exercise improves plasmatic levels of IL-10, left ventricular end-diastolic pressure, and muscle lipid peroxidation in chronic heart failure rats.

Chronic heart failure (CHF) is characterized by left ventricular dysfunction, resulting in hemodynamic changes, sustained inflammatory state, as well as increase in oxidative stress. Physical exercise has been described as an important nonpharmacological procedure in the treatment of CHF, contributing to the improvement of the clinical outcomes in this disease. This study evaluated the effects of physical training on hemodynamics, muscle lipid peroxidation, and plasmatic levels of IL-10 in CHF rats. The left coronary artery was ligated to induce CHF, or sham operation was performed in control groups. Rats were assigned to one of four groups: trained CHF (T-CHF, n = 10), sedentary CHF (S-CHF, n = 10), trained sham (T-Sham, n = 10), or sedentary sham (S-Sham, n = 10). Trained animals had carried out a swimming protocol, 60 min/day, 5 days/wk, during 8 wk, whereas sedentary animals remained without training. Eight weeks of physical training promoted an improvement of diastolic function represented by a reduction of the left ventricular end-diastolic pressure in the T-CHF group compared with the S-CHF group (P < 0.05). Lipid peroxidation evaluated in gastrocnemius muscle using thiobarbituric acid reactive substance assay was higher in the S-CHF group compared with all other groups (P < 0.05). However, there were no differences between T-CHF compared with S-Sham and T-Sham groups. The plasmatic levels of IL-10 were lower in the S-CHF group compared with all other groups (P < 0.05). These findings demonstrate that regular physical training using a swimming protocol, with duration of 8 wk, improves the cardiac function and the anti-inflammatory response and reduces muscle cellular damage.     

Biotechnological applications of brown spider (Loxosceles genus) venom toxins

Loxoscelism (the term used to define accidents by the bite of brown spiders) has been reported worldwide. Clinical manifestations following brown spider bites are frequently associated with skin degeneration, a massive inflammatory response at the injured region, intravascular hemolysis, platelet aggregation causing thrombocytopenia and renal disturbances. The mechanisms by which the venom exerts its noxious effects are currently under investigation. The whole venom is a complex mixture of toxins enriched with low molecular mass proteins in the range of 5–40 kDa. Toxins including alkaline phosphatase, hyaluronidase, metalloproteases (astacin-like proteases), low molecular mass (5.6–7.9 kDa) insecticidal peptides and phospholipases-D (dermonecrotic toxins) have been identified in the venom. The purpose of the present review is to describe biotechnological applications of whole venom or some toxins, with especial emphasis upon molecular biology findings obtained in the last years.     

Staphylococcus aureus requires at least one FtsK/SpoIIIE protein for correct chromosome segregation

Faithful coordination between bacterial cell division and chromosome segregation in rod‐shaped bacteria, such as Escherichia coli and Bacillus subtilis, is dependent on the DNA translocase activity of FtsK/SpoIIIE proteins, which move DNA away from the division site before cytokinesis is completed. However, the role of these proteins in chromosome partitioning has not been well studied in spherical bacteria. Here, it was shown that the two Staphylococcus aureus FtsK/SpoIIIE homologues, SpoIIIE and FtsK, operate in independent pathways to ensure correct chromosome management during cell division. SpoIIIE forms foci at the centre of the closing septum in at least 50% of the cells that are close to complete septum synthesis. FtsK is a multifunctional septal protein with a C‐terminal DNA translocase domain that is not required for correct chromosome management in the presence of SpoIIIE. However, lack of both SpoIIIE and FtsK causes severe nucleoid segregation and morphological defects, showing that the two proteins have partially redundant roles in S. aureus.     

Acute and chronic influence of hemodialysis according to the membrane used on phagocytic function of neutrophils and monocytes and pro-inflammatory cytokines production in chronic renal failure patients

This work evaluated the phagocytic capacity of monocytes and neutrophils, and tumor necrosis factor-alpha, interleukin 6, 1 and 8 serum levels in chronic renal failure patients under peritoneal dialysis and hemodialysis treatment, compared with chronic renal failure patients without dialysis treatment and healthy individuals, in order to contribute to a better understanding of the action of these therapies on the evolution of chronic renal failure patients. All patients with chronic renal failure (under dialysis or not) showed decreased phagocytic capacity of neutrophils and monocytes. All those in hemodialysis (cellulose acetate or polysulfone membranes) showed a decreased phagocytic capacity. The phagocytic index for neutrophil was 13 times lower than that of the control group for both membranes, whereas for monocytes, only those using polysulfone membrane showed a significant decrease of 4.9 times in phagocytic capacity. There was an acute stimulation of the phagocytosis by neutrophils after a single session of dialysis with both types of membrane, while only cellulose acetate membrane decreased the phagocytic index of monocytes after the hemodialysis session. Patients using cellulose acetate showed a chronic increase in tumor necrosis factor-alpha serum levels, while those using polysulfone showed a chronic increase in interleukin 6. After a single hemodialysis procedure, no acute effect of the treatment on tumor necrosis factor-alpha and interleukin 6 levels was identified. The decreased phagocytic function of neutrophils and monocytes may account for the high levels of susceptibility of chronic renal failure patients to infections with pyogenic bacteria and tuberculosis. Furthermore, inflammatory activity may occur with both types of membrane studied, suggesting that it will be useful for these patients to evaluate some anti-inflammatory or anti-cytokine therapies against tumor necrosis factor-alpha and interleukin 6, in order to avoid cardiovascular complication.