Laccase production and wood degradation byTrametes hirsuta

The laccase production byT. hirsuta was better in lignin as compared to malt extract media. Tannic acid gave the best laccase yield out of different lignins, phenolic compounds and sugars tested as substrates. The sugars proved to be good substrates for growth only. The role ofT. hirsuta in semisolid fermentation of sawdust was studied with reference to its capacity to degrade lignin in its native form. During two months of decay an overall weight loss of 22.2% along with a lignin loss of 13.6% was recorded.     

Detection of oral squamous cell carcinoma with ex vivo fluorescence confocal microscopy: Sensitivity and specificity compared to histopathology

Real‐time microscopic imaging of freshly excised tissue enables a rapid bedside‐pathology. A possible application of interest is the detection of oral squamous cell carcinomas (OSCCs). The aim of this study was to analyze the sensitivity and specificity of ex vivo fluorescence confocal microscopy (FCM) for OSCCs and to compare confocal images visually and qualitatively with gold standard histopathology. Two hundred eighty ex vivo FCM images were prospectively collected and evaluated immediately after excision. Every confocal image was blindly assessed for the presence or absence of malignancy by two clinicians and one pathologist. The results were compared with conventional histopathology with hematoxylin and eosin staining. OSCCs were detected with a very high sensitivity of 0.991, specificity of 0.9527, positive predictive value of 0.9322 and negative predictive value of 0.9938. The results demonstrate the potential of ex vivo FCM in fresh tissue for rapid real‐time surgical pathology.     

How does feedback from phage infections influence the evolution of phase variation in Campylobacter?

Campylobacter jejuni (C. jejuni) causes gastroenteritis following the consumption of contaminated poultry meat, resulting in a large health and economic burden worldwide. Phage therapy is a promising technique for eradicating C. jejuni from poultry flocks and chicken carcasses. However, C. jejuni can resist infections by some phages through stochastic, phase-variable ON/OFF switching of the phage receptors mediated by simple sequence repeats (SSR). While selection strength and exposure time influence the evolution of SSR-mediated phase variation (PV), phages offer a more complex evolutionary environment as phage replication depends on having a permissive host organism. Here, we build and explore several continuous culture bacteria-phage computational models, each analysing different phase-variable scenarios calibrated to the experimental SSR rates of C. jejuni loci and replication parameters for the F336 phage. We simulate the evolution of PV rates via the adaptive dynamics framework for varying levels of selective pressures that act on the phage-resistant state. Our results indicate that growth reducing counter-selection on a single PV locus results in the stable maintenance of the phage, while compensatory selection between bacterial states affects the evolutionary stable mutation rates (i.e. very high and very low mutation rates are evolutionarily disadvantageous), whereas, in the absence of either selective pressure the evolution of PV rates results in mutation rates below the basal values. Contrastingly, a biologically-relevant model with two phase-variable loci resulted in phage extinction and locking of the bacteria into a phage-resistant state suggesting that another counter-selective pressure is required, instance, the use of a distinct phage whose receptor is an F336-phage-resistant state. We conclude that a delicate balance between counter-selection and phage-attack can result in both the evolution of phase-variable phage receptors and persistence of PV-receptor-specific phage.     

Purification and characterization of cellulolytic enzymes fromTrichoderma harzianum

Two forms of filter paper activity (filter paper activity; cellulose 1,4-β-cellobiosidase, EC 3.2.1.91) and single forms of CM-cellulase (carboxymethyl cellulase; endo-l,4-β-glucanase, EC 3.2.1.4) and β-glucosidase (β-D-glucoside glucohydrolase, EC 3.2.1.21) from the culture filtrate ofTrichoderma harzianum were separated and partially purified by (NH₄)₂SO₄ precipitation, ion-exchange chromatography and gel filtration. The final preparation was purified about 12-, 20- and 27-fold for FP-activity, CM-oellulase and β-glueosidase, respectively. The pH and temperature optima, stability, kinetic parameters, effeet of metal ions and molar mass of each was determined. A distinct type of synergistic action between cellulase components was observed for efficientin vitro saccharification of dewaxed cotton.