Domains of the Pavarotti kinesin-like protein that direct its subcellular distribution: effects of mislocalisation on the tubulin and actin cytoskeleton during Drosophila oogenesis

The kinesin-like protein encoded by pavarotti (Pav-KLP) is essential for cytokinesis and associates with the central part of the late mitotic spindle and interphase nuclei in somatic cells (Adams et al., 1988). Here we define regions of the molecule that regulate its subcellular localisation and study the consequences of overexpressing mutant forms of the protein during oogenesis in Drosophila. Pav-KLP normally associates with the oocyte nucleus, but when over-expressed at moderate levels, its GFP tagged form also accumulates in nurse cell nuclei. At high expression levels this leads to loss of the microfilaments that tether these nuclei, so that they block the ring canals and prevent the 'dumping' of nurse cell cytoplasm into the oocyte, which results in sterility. Localisation to these nuclei is prevented by mutations in either the conserved ATP-binding site of the motor domain or the nuclear localisation sequences in the C-terminal domain. Both such mutations lead to the formation of stable arrays of cytoplasmic microtubules and the progressive disruption of the actin cytoskeleton. The latter is evident by a breakdown of the cortical actin causing disruption of cell membranes; this breakdown ultimately results in the accumulation of cytoplasmic aggregates containing tubulin, actin and at least some of their binding proteins. Pav-KLP is also found associated with the ring canals, actin-rich structures built from remnants of the cytokinesis ring. The stalk domain alone is sufficient for the exclusive association of Pav-KLP to these structures, and this has no consequences for fertility. We discuss whether disruption of actin structures by full-length cytoplasmic forms of Pav-KLP is a consequence of the resulting stabilised cytoplasmic microtubules per se or accumulation of the motor protein at ectopic cortical sites to sequester molecules that regulate actin behaviour

Moser-Tardos Algorithm with small number of random bits

We study a variant of the parallel Moser-Tardos Algorithm. We prove that if we restrict attention to a class of problems whose dependency graphs have subexponential growth, then the expected total number of random bits used by the algorithm is constant; in particular, it is independent from the number of variables. This is achieved by using the same random bits to resample variables which are far enough in the dependency graph. There are two corollaries. First, we obtain a deterministic algorithm for finding a satisfying assignment, which for any class of problems as in the previous paragraph runs in time O(n), where n is the number of variables. Second, we present a Borel version of the Lov\'asz Local Lemma.Comment: 31 pages; minor corrections and changes; note that the required bound on the failure probabilities in Theorems 2.5 and 3.28 is slightly stronger than in Version

The Carpathian lingonberry, raspberry and blackberry fruit extracts feature variable antimicrobial efficiency

Wild berry is an excellent source of phytonutrients and/or bioactive compounds associated with significant therapeutic properties, so that they have been utilized in folk medicine and traditional nutrition throughout centuries. Multiple health-promoting effects, such as anti-inflammatory, anti-diabetic, anti-heart and coronary disease properties were attributed to such wild berries. It has also been proved that berries could feature antimicrobial effects that could be of a great importance for the prevention of food-feed poisoning and fighting back antibiotic resistance. In this study, we investigated the antimicrobial properties of lingonberry (Vaccinium vitis-idaea), raspberry (Rubus idaeus) and blackberry (Rubus fruticosus) crude and ethanolic extracts prepared from fruits obtained from the spontaneous flora of Eastern Carpathian Mountains situated in Transylvania. The antimicrobial effect of crude and alcoholic extracts were assessed on four Gram-negative, five Gram-positive bacteria and one yeast species using the agar diffusion method. The studied bacteria can cause food or feed spoilage and foodborne diseases. Our results indicate the significant inhibitory effect of lingonberry extracts in the case of Gram-negative bacteria like Proteus vulgaris and Salmonella Hartford, while among Gram-positive bacteria the strongest inhibitory effect was observed for Bacillus species like B. cereus, B. subtilis, B. mojavensis and Micrococcus luteus. The raspberry and blackberry extracts featured milder inhibitory effects in the case of the studied bacteria species. Furthermore, we have studied the crude or ethanolic extract combinations associated antimicrobial effects synergistic/additive or antagonistic properties. Interestingly, the triple and double ethanolic extract mixes had stronger antimicrobial properties, whereas the crude extract mixes showed relatively reduced effects, if any. Our results indicate that the antimicrobial activity of studied fruit extracts obtained from wild berries can vary upon the applied extraction method and their combination formulae, so that all these considerations must be taken into account when such fruit extracts are considered for foodstuff development