Ligninolytic activity of tropical rainforest basidiomycetes

A total of 116 strains of Brazilian tropical rainforest basidiomycetes were evaluated in terms of their ability to oxidize the dye rhemazol brilliant blue R (RBBR) and guaiacol. Laccase and peroxidase activities were detected by the drop test using solutions of α-naphthol and pyrogallol, respectively. RBBR and guaiacol oxidation occurred in 96.6 and 87.1% of the strains tested, respectively. One hundred strains oxidized both substrates. In the drop test, most strains presented laccase (96.6%) and peroxidase (92.2%) activity. The quick screening method used here can be useful to identify ligninolytic fungal strains to be used in various biotechnological applications. This revised version was published online in November 2006 with corrections to the Cover Date.     

Alteration in the endogenous intestinal flora of Swiss Webster mice by experimental Angiostrongylus costaricensis infection

The association between worm infections and bacterial diseases has only recently been emphasized. This study examined the effect of experimental Angiostrongylus costaricensis infection on endogenous intestinal flora of Swiss Webster mice. Eight mice aging six weeks were selected for this experiment. Four were infected with A. costaricensis and the other four were used as controls. Twenty eight days after the worm infection, all mice in both groups were sacrificed and samples of the contents of the ileum and colon were obtained and cultured for aerobic and anaerobic bacteria. In the mice infected with A. costaricensis there was a significant increase in the number of bacteria of the endogenous intestinal flora, accompanied by a decrease in the number of Peptostreptococcus spp. This alteration in the intestinal flora of mice infected by the nematode may help to understand some bacterial infections described in humans.     

Insulin Accelerates Seedling Growth of Canavalia ensiformis (Jack bean)

Insulin is a 6 kDa peptide hormone that activates several metabolic processes and cellular growth. Germination studies showed that insulin, vanadyl sulphate (an insulin mimetic compound), tyrphostin (an inhibitor of insulin receptor kinase activity), pinitol (a chiro inositol analogue) and glucose were able to accelerate Canavalia ensiformis (Jack bean) seedling radicle and epicotyl development. Immunofluorescence microscopy analysis showed that proteins binding to insulin, insulin receptor and phosphoserine antibodies are localized in an internal layer of the C. ensiformis seed coat. These results and others previously reported from our laboratory suggest that insulin, insulin receptor and phosphoserine proteins could be components of signalling pathways akin to those present in animals.     

On the use of 2,1,3-benzothiadiazole derivatives as selective live cell fluorescence imaging probes

Newly designed 2,1,3-benzothiadiazole-containing fluorescent probes with four excited state intramolecular proton transfer (ESIPT) sites were successfully tested in live cell-imaging assays using a confluent monolayer of human stem-cells (tissue). All tested dyes were compared with the commercially available DAPI and gave far better results.     

Metabolism of Plant Polysaccharides by Leucoagaricus gongylophorus, the Symbiotic Fungus of the Leaf-Cutting Ant Atta sexdens L.

Atta sexdens L. ants feed on the fungus they cultivate on cut leaves inside their nests. The fungus, Leucoagaricus gongylophorus, metabolizes plant polysaccharides, such as xylan, starch, pectin, and cellulose, mediating assimilation of these compounds by the ants. This metabolic integration may be an important part of the ant-fungus symbiosis, and it involves primarily xylan and starch, both of which support rapid fungal growth. Cellulose seems to be less important for symbiont nutrition, since it is poorly degraded and assimilated by the fungus. Pectin is rapidly degraded but slowly assimilated by L. gongylophorus, and its degradation may occur so that the fungus can more easily access other polysaccharides in the leaves.     

Yarrowia lipolytica lipase production enhanced by increased air pressure

Aims: To study the cellular growth and morphology of Yarrowia lipolytica W29 and its lipase and protease production under increased air pressures. Methods and Results: Batch cultures of the yeast were conducted in a pressurized bioreactor at 4 and 8 bar of air pressure and the cellular behaviour was compared with cultures at atmospheric pressure. No inhibition of cellular growth was observed by the increase of pressure. Moreover, the improvement of the oxygen transfer rate (OTR) from the gas to the culture medium by pressurization enhanced the extracellular lipase activity from 96·6 U l^?1 at 1 bar to 533·5 U l^?1 at 8 bar. The extracellular protease activity was reduced by the air pressure increase, thereby eliciting further lipase productivity. Cell morphology was slightly affected by pressure, particularly at 8 bar, where cells kept the predominant oval form but decreased in size. Conclusions: OTR improvement by total air pressure rise up to 8 bar in a bioreactor can be applied to the enhancement of lipase production by Y. lipolytica. Significance and Impact of the Study: Hyperbaric bioreactors can be successfully applied for yeast cells cultivation, particularly in high‐density cultures used for enzymes production, preventing oxygen limitation and consequently increasing overall productivity.     

Mutations in methylenetetrahydrofolate reductase and in cysthationine beta synthase: is there a link to homocysteine levels in peripheral arterial disease?

Peripheral arterial disease (PAD) is an atherosclerotic disturbance characterized by a progressive obstruction of lower limb arteries. Many risk factors associated with PAD development have being reported in the literature. The present study aimed to investigate whether mutations in the methylenetetrahydrofolate reductase (MTHFR) or in the cystathionine beta synthase (CBS) genes are associated with higher levels of homocysteine and the risk of PAD in patients from Brazil. This study analyzed 39 patients with PAD and 32 without PAD in whom risk factors and C677T mutations in the MTHFR gene and both 844ins68 and T833C mutations in the CBS gene were investigated. Although higher levels of homocysteine could be observed in patients with PAD compared to controls, no association between the increase of homocysteine and the frequency of C677T, 844ins68, and T833C mutations could be observed. The results suggest that these mutations do not appear to be related to either homocysteine levels or the development of the disease. However, hyperhomocysteinemia and smoking are important factors in PAD development.     

Phytochemical Characterization of Cannabis sativa L. Roots from Northeastern Brazil

This article describes the phytochemical study of Cannabis sativa roots from northeastern Brazil. The dried plant material was pulverized and subjected to exhaustive maceration with ethanol at room temperature, obtaining the crude ethanolic extract (Cs-EEBR). The volatile compounds were analyzed by gas chromatography coupled with mass spectrometry (GC/MS), which allowed to identify 22 compounds by comparing the linear retention index (LRI), the similarity index (SI) and the fragmentation pattern of the constituents with the literature. By this technique the major compounds identified were: friedelan-3-one and β-sitosterol. In addition, two fractions were obtained from Cs-EEBR by classical column chromatography and preparative thin layer chromatography. These fractions were analyzed by NMR and IR and together with the mass spectrometry data allowed to identify the compounds: epifriedelanol, friedelan-3-one, β-sitosterol and stigmasterol. The study contributed to the phytochemical knowledge of Cannabis sativa, specifically the roots, as there are few reports on the chemical constituents of this part of the plant.     

Intravoxel Incoherent Motion Diffusion Weighted MR Imaging at 3.0 T: Assessment of Steatohepatitis and Fibrosis Compared with Liver Biopsy in Type 2 Diabetic Patients

ObjectiveTo evaluate the capability of intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) to assess steatohepatitis and fibrosis determined by histopathology in type 2 diabetic patients.MethodsFifty-nine type 2 diabetic patients (49 women, 10 men; mean age, 54 ± 9 years) were submitted to liver biopsy for the evaluation of non-alcoholic fatty liver disease (NAFLD) and underwent DWI on a 3.0T MR system using 10 b values. Institutional approval and patient consent were obtained. Pure molecular-based (D), perfusion-related (D*), and vascular fraction (f) were calculated using a double exponential model and least squares curve fitting. D, D*, and f were compared between patients with and without steatohepatitis and between patients with and without fibrosis. The variables were compared by using the Ranksum test and Student t-test.ResultsSteatohepatitis was observed in 22 patients and fibrosis in 16 patients. A lower D median (0.70 s/mm² vs. 0.83 s/mm², p<0.05) and a lower D* median (34.39 s/mm² vs. 45.23 s/mm², p<0.05) were observed among those with steatohepatitis. A lower D median (0.70 s/mm² vs. 0.82 s/mm², p<0.05) and a lower D* median (35.01 s/mm² vs. 44.76 s/mm², p=0.05) were also observed among those with fibrosis.ConclusionIVIM-DWI has the potential to aid in the characterization of steatohepatitis and fibrosis.