Results 1 - 10 of 4884
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[en] The diversity of polyketide synthase (PKS) genes in Aspergillus ochraceus NRRL 3174 and Aspergil- lus carbonarius 2Mu134 has been investigated using different primer pairs previously developed for the ketosynthase (KS) domain of fungal PKSs. Nine different KS domain sequences in A. ochraceus NRRL 3174 as well as five different KS domain sequences in A. carbonarius 2Mu134 have been identified. The identified KS fragments were distributed in five different clusters on the phylogenetic tree, indicating that they most probably represent PKSs responsible for different functions. (author)
[en] Filamentous fungi are very successful in colonising various microconfined environments, but their behaviour is usually tested on flat surfaces. This contribution presents the design, the fabrication and the use of microstructures, made of a biocompatible polymer (poly(dimethylsiloxane), PDMS) for studying the dynamic micro-scale behaviour of the filamentous fungus Neurospora crassa. The proposed methodology is simple to implement and uses low cost fabrication methods. The observations of the fungus growing through a variety of fabricated micro-environments revealed distinct structure-dependent and structure-induced responses. Generalising the proposed methodology we propose a tool for high-throughput studies of numerous fungal species.
[en] A novel configuration of dual-channel line optical tweezers with a ‘Y’ shape is constructed for sorting of particles within a microfluidic chip. When yeast cells with different size pass the intersection of the specially designed line optical tweezers, they are separated and transported to different channels due to a difference in the forces exerted by the line tweezers that depends on the size of the cells. The influences of some experimental conditions, such as laser power and flow velocity, on the sorting efficiency are discussed. (paper)
[en] Two depsides (atranorin 1 and evernic acid 4), an aromatic compound (methyl β-orcinolcarboxylate 2) and one cleavage product of depside (everninic acid 3) were isolated from two lichens, Cladonia multiformis (1 and 2) and Cryptothecia sp. (3 and 4). The identification of the four compounds was carried out by comparison of the recorded NMR data with that of the reported. Compounds 1 and 4 showed antibacterial activity against Bacillus subtilis and Enterobacter aerogenes. (author)
[en] Highlights: • Biocrust cover, richness and composition were mostly unresponsive to changes in landscape structure. • Soil properties better explained the variation in biocrust cover and diversity. • Species composition in biocrust and vascular plant communities were coupled. • Some biocrust species can act as indicators of fragment area, connectivity and distance to road. • Landscape structure and habitat quality need to be evaluated jointly to assess fragmentation impacts on biocrusts. Biological soil crusts (or biocrusts) are widespread, diverse and important components of drylands sometimes threatened by global change drivers. However, their response to fragmentation processes is poorly known. The aim of this study was to assess the effects of changing landscape structure, given by land use change and the presence of linear infrastructure (e.g., roads), on the cover and diversity of lichen-biocrusts. We also evaluated the influence of several subrogates of fragment quality, such as soil properties, vascular plant community structure and topography. Biocrust cover and diversity were measured in 50 remnants of a Mediterranean shrubland. The fragments varied in size, connectivity and distance to a road, but also in plant and soil attributes, topography and fragment history. We applied general linear and mixed models to assess the effects of environmental variables on biocrust communities. Biocrust cover, richness and species composition were mostly unresponsive to changes in landscape structure, while connectivity and distance to the road decreased species diversity. Soil properties better explained the variation in biocrust cover and diversity. Changes in plant community and biocrust community composition were coupled. We also identified several biocrust species with strong capacity to reflect landscape structure. Our findings suggest that landscape structure needs to be evaluated jointly with other environmental factors to fully understand the consequences of fragmentation processes on biocrust communities and the subsequent implications for their functional role in drylands.
[en] Boolean networks are widely used model to represent gene interactions and global dynamical behavior of gene regulatory networks. To understand the memory effect involved in some interactions between biological components, it is necessary to include delayed influences in the model. In this paper, we present a logical method to learn such models from sequences of gene expression data. This method analyzes each sequence one by one to iteratively construct a Boolean network that captures the dynamics of these observations. To illustrate the merits of this approach, we apply it to learning real data from bioinformatic literature. Using data from the yeast cell cycle, we give experimental results and show the scalability of the method. We show empirically that using this method we can handle millions of observations and successfully capture delayed influences of Boolean networks.
[en] Wilt caused by Fusarium oxysporum is considered as the most damaging soil disease of lentil. Current study was carried out to see the effect of Fusarium wilt disease on seed yield of advance lentil genotypes in wilt sick plot. Fourteen entries were tested in national yield uniform trial (NUYT), 11 in adaptation yield trial (AYT), 15 in advance line yield trial-I (ALYT-I), 12 in advance line yield trial-II (ALYT-II) and 25 in preliminary yield trial (PYT) along with standard check. Mean seed yields of 891.04, 1281.78, 1153.81, 1080.04 and 789.45 kg ha/sup -1/were observed in NUYT, AYT, ALYT-I, ALYT-II and PYT, respectively. The average disease intensity in various trials was more than 30%. Disease severity was less than 10% in nine genotypes. This was also confirmed by high negative values of their losses over check. Out of these, the genotypes, 03501, NL 96625, NL 66184, NL 66106 and NL 31742/03 produced highest seed yield of 2945 kg ha/sup -1/, 2667 kg ha/sup -1/, 2490 kg ha/sup -1/,2390 kg ha/sup -1/and 2691 kg ha/sup -1/ respectively. The higher yield may be attributed to inbuilt resistance against such a drastic disease. Overall, seed yield and disease incidence were negatively correlated in all yield trials. The genotypes under severe wilt attack produced no seed yield. It is clear from this study that resistance/tolerance is available in lentil that can be selected based on high yield potential along with minimum yield losses for further breeding. (author)
[en] Parmelia sulcata transplants were positioned in three different exposure systems allowing three different influxes: free influx (Fi), horizontal influx (Hi) and vertical influx (Vi). Results suggest the absence of any wind-directional effects on element accumulation within Fi and Hi systems, but underline that differences in response may be observed in relation with the transplant set-up systems. The Vi system generally shows poor results, while the performance of the Hi and Fi systems depends on the element involved. Results were obtained for a specific lichen, and therefore are not necessarily representative for other lichens. (author)
[en] Chickpea (Cicer arietinum L.) an important food legume, ranks third in the world. In Pakistan yield of chickpea is low due to the prevalence of wilt and blight diseases - the two destructive diseases. The control measures available are not feasible and economical, except to exploit host plant resistance mechanism to identify the sources of resistance in existing chickpea germplasm. Fifty four advance chickpea genotypes were screened in blight screening nursery and wilt sick plot. Out of total 54 genotypes 23 were resistant and 16 were moderately resistant to Ascochyta blight disease. Among 23 resistant genotypes; K0058-09, K0062-09, K0066-09, D095-09, K07A005, BK05A015 and BK04A013 had disease rating mean of 3. The results of early wilt showed 19 genotypes as highly resistant and 15 as resistant. The genotypes K0070-09, BKK17106, CH 65/02 and BK04A013 were highly susceptible to wilt during early pathogen infection at seedling stage while the genotypes K0063-09, BKK17106 and BK04A013 were susceptible during late season. Resistance sources identified could be exploited directly and also may be transferred through hybridization to high yielding disease susceptible genotypes. (author)
[en] In recent years, biological micro-electro-mechanical systems (commonly referred to as BioMEMS) have found widespread use, becoming increasingly prevalent in diagnostics and therapeutics. Cell-based sensors are nowadays gaining increasing attention, due to cellular built-in natural selectivity and physiologically relevant response to biologically active chemicals. On the other hand, surrogate microbial systems, including yeast models, have become a useful alternative to animal and mammalian cell systems for high-throughput screening for the identification of new pharmacological agents. A main obstacle in biosensor device fabrication is the need for localized geometric confinement of cells, without losing cell viability and sensing capability. Here we illustrate a new approach for cellular patterning using dewetting processes to control cell adhesion and spatial confinement on modified surfaces. By the control of simple system parameters, a rich variety of morphologies, ranging through hexagonal arrays, polygonal networks, bicontinuous structures, and elongated fingers, can be obtained