Direct amplification of new cellulase genes from woodland soil purified DNA

Eight genes encoding cellulolytic enzymes were obtained by direct PCR amplification of genomic DNA recovered from woodland soil samples. The direct amplifications were carried out by using primers designed from available online cellulase nucleotide sequences. The isolated genes were all different from each other and homologous to endo-β-1,4-glucanases of Bacillus subtilis. The cellulases were functionally expressed in Escherichia coli and tested on soluble substrate at 37 and 60 °C, showing different cellulolytic activities. Among these, the enzyme renamed CelWS6 exhibited good activity at higher temperatures. Further analysis of CelWS6 showed a high performance in acid environments (between pH 4.0 and 6.0) and at elevated temperatures with its maximum activity at pH 5.0 and 50 °C. At the optimum pH, it was very stable since more than 80 % of its original activity was maintained after an incubation of 120 min at 60 °C. Because the cellulases had different cellulolytic activities, but similar amino acid sequences, it was possible to assess the relationship between sequence and protein function.     

Cephalosporin resistant Escherichia coli from cancer patients in Cairo,Egypt

Cephalosporin‐resistant Escherichia coli has been increasingly reported worldwide. In this study, 32 cephalosporin resistant E. coli isolates identified from cancer patients in Cairo, Egypt in 2009–2010 were analyzed. Twenty‐three were of phylogenetic group D, seven A and one each B1 and B2. By rep‐PCR 15 phylogroup D isolates were grouped in four clusters, one with sequence type (ST) 405 and three ST68. Seventeen isolates showed single patterns. bla_CTX‐M‐15 and aac(6')‐Ib‐cr were the most common resistance determinants. bla_OXA‐48 and bla_VIM were also detected. Multidrug resistant E. coli seriously affects healthcare, especially in immunocompromised hosts, such as cancer patients.     

Mixtures with grass litter may hasten shrub litter decomposition after shrub encroachment into mountain grasslands

Aims

Shrub encroachment in mesic grasslands alters the identity and quality of litters entering the system. As litter from shrubs and grasses can differ in their quality, this can lead to differences in litter decomposition by the direct effect of quality, but also to litter interaction during decomposition. The objective of this study was to examine the occurrence of non-additive effects of litter mixtures on the decomposition rates of legume shrub litter (poor in P) or conifer shrub litter (poor in N) and grass litter.

Methods

In addition to single litter type litterbags for the three species, we mixed litters of each pair of possible combinations to determine the influence of each species on mass loss. Litterbags were placed in the field and collected after 1, 6, 8, 12 and 24 months. In each collection, litter of each species remaining in mixed bags was separated, dry weighed and analyzed for C, N and P.

Results

With respect to shrub litter decomposing alone, mass loss of shrub litter when mixed with grass showed a 9–10 % increase in decomposition rate for conifer and a 3 % increase for legume litter. These litter mixture effects varied with time and they were detected after a decomposition period of 1 year in legume litter and of 2 years in conifer litter.

Conclusions

Grass litter hastened conifer and legume litter decomposition in leaf litter mixtures, at least during the first stages of the process. The potential consequences of this result to alter litter accumulation patterns and thus carbon sequestration rates after shrub encroachment into grasslands will depend on whether the observed trends are maintained in the advanced decomposition stages.     

Morpho-physiological responses of sugar beet (Beta vulgaris L.) genotypes to drought stress

The identification of morpho-physiological traits related to drought tolerance and high yield potential is a challenge when selecting sugar beet genotypes with greater tolerance to water stress. In this paper, root morphological parameters, antioxidant systems, leaf relative water content (RWC) and H⁺-ATPase activity as key morpho-physiological traits involved in drought tolerance/susceptibility of sugar beet were studied. Genotypes showing a different drought tolerance index (DTI) but a similar yield potential, under moderate (?0.6 Mpa) and severe (?1.2 MPa) water stress, were selected and their morpho-physiological traits were investigated. The results showed a wide genetic variation in morpho-physiological parameters which demonstrated the different adaptive strategies under moderate and severe drought conditions in sugar beet. In particular, an efficient antioxidant system and redox signalling made some sugar beet genotypes more tolerant to drought stress. The alternative strategy of other genotypes was the reduction of root tissue density, which produced a less dense root system improving the axial hydraulic conductivity. These results could be considered as interesting challenge for a better understanding of the drought tolerance mechanisms in sugar beet.     

CHF5074 restores visual memory ability and pre‐synaptic cortical acetylcholine release in pre‐plaque Tg2576 mice

CHF5074, a new microglial modulator, attenuates memory deficit in Alzheimer's disease transgenic mice. In this study, the effect of an acute or subacute CHF5074 treatment on in vivo novel object recognition test and on [³H]Acetylcholine (ACh) and GABA release in pre‐plaque (7‐month‐old) Tg2576 mice have been compared with those induced by the γ‐secretase inhibitor LY450139 (semagacestat). Vehicle‐treated Tg2576 mice displayed an impairment of recognition memory compared with wild‐type animals. This impairment was recovered in transgenic animals acutely treated with CHF5074 (30 mg/kg), while LY450139 (1, 3, 10 mg/kg) was ineffective. In frontal cortex synaptosomes from vehicle‐treated Tg2576 mice, K⁺‐evoked [³H]ACh release was lower than that measured in wild‐type mice. This reduction was absent in transgenic animals subacutely treated with CHF5074 (30 mg/kg daily for 8 days), while it was slightly, not significantly, amplified by LY450139 (3 mg/kg daily for 8 days). There were no differences between the groups on spontaneous [³H]ACh release as well as spontaneous and K⁺‐evoked GABA release. These results suggest that CHF5074 has beneficial effects on visual memory and cortical cholinergic dysfunctions in pre‐plaque Tg2576 mice. Together with previous findings, these data suggest that CHF5074 could be a possible candidate for early Alzheimer's disease therapeutic regimens.     

Disruption of Ttll5/Stamp Gene (Tubulin Tyrosine Ligase-like Protein 5/SRC-1 and TIF2-associated Modulatory Protein Gene) in Male Mice Causes Sperm Malformation and Infertility

TTLL5/STAMP (tubulin tyrosine ligase-like family member 5) has multiple activities in cells. TTLL5 is one of 13 TTLLs, has polyglutamylation activity, augments the activity of p160 coactivators (SRC-1 and TIF2) in glucocorticoid receptor-regulated gene induction and repression, and displays steroid-independent growth activity with several cell types. To examine TTLL5/STAMP functions in whole animals, mice were prepared with an internal deletion that eliminated several activities of the Stamp gene. This mutation causes both reduced levels of STAMP mRNA and C-terminal truncation of STAMP protein. Homozygous targeted mutant (Stamp^tm/tm) mice appear normal except for marked decreases in male fertility associated with defects in progressive sperm motility. Abnormal axonemal structures with loss of tubulin doublets occur in most Stamp^tm/tm sperm tails in conjunction with substantial reduction in α-tubulin polyglutamylation, which closely correlates with the reduction in mutant STAMP mRNA. The axonemes in other structures appear unaffected. There is no obvious change in the organs for sperm development of WT versus Stamp^tm/tm males despite the levels of WT STAMP mRNA in testes being 20-fold higher than in any other organ examined. This defect in male fertility is unrelated to other Ttll genes or 24 genes previously identified as important for sperm function. Thus, STAMP appears to participate in a unique, tissue-selective TTLL-mediated pathway for α-tubulin polyglutamylation that is required for sperm maturation and motility and may be relevant for male fertility.     

Molecular Mechanism by Which a Potent Hepatitis C Virus NS3-NS4A Protease Inhibitor Overcomes Emergence of Resistance

Although optimizing the resistance profile of an inhibitor can be challenging, it is potentially important for improving the long term effectiveness of antiviral therapy. This work describes our rational approach toward the identification of a macrocyclic acylsulfonamide that is a potent inhibitor of the NS3-NS4A proteases of all hepatitis C virus genotypes and of a panel of genotype 1-resistant variants. The enhanced potency of this compound versus variants D168V and R155K facilitated x-ray determination of the inhibitor-variant complexes. In turn, these structural studies revealed a complex molecular basis of resistance and rationalized how such compounds are able to circumvent these mechanisms.     

Males with a Faster Courtship Display have More White Spots and Higher Pairing Success in the Diamond Firetail,Stagonopleura guttata

There is growing evidence that female mate choice could be based on a combination of multiple signals that often involve both ornamental colourful traits and behavioural displays. The Diamond Firetail is an Australian finch with a variable number of white spots on their black flank feathers. The number of white spots is a dimorphic characteristic: females have more spots than males, and males prefer females with many spots. Previously, we found assortative pairing for spot number despite the absence of experimental evidence for female preference for male spot number. Here, we test whether the male behavioural courtship display (bobbing while waving a grass stem) correlates with male spot number and pairing success. We also test whether male spot number predicts the outcome (winner or loser) of intrasexual competition over courtship materials (grass stem, perch, nest site). Males with many spots had higher pairing success, and male spot number correlated with the intensity of courtship display. In a multivariate statistical analysis, male courtship display was the stronger predictor of male pairing success. Finally, male spot number predicted the outcome of intrasexual interactions: males with many spots consistently won contests over grass stems, perches and nest sites. We suggest that intrasexual selection could favour male spot number, whereas courtship intensity appears to be under stronger intersexual selection.