Comparsion ofin vitro activities of antifungal drugs and propolis against yeasts isolated from patients with superficial mycoses

Thein vitro susceptibilities of propolis and antifungal drugs were determined against some yeasts isolated from patients with superficial mycoses. The agents tested included fluconazole, itraconazole, ketoconazole, terbinafine and propolis. MICs were determined by the broth microdilution technique following National Committee for Clinical Laboratory Standards document M27-P. For allCandida albicans isolates from the patients with superficial mycoses, ketoconazole presented higher (P<0.05) efficiency than that of the other antifungal agents tested. The geometric mean MIC values of antifungal drugs and propolis against the yeasts tested ranged from 0.087 to 12.69 μg/mL and 0.4–0.6 μg/mL, respectively. Propolis also showed an important antifungal activity against the yeasts tested, MIC ranges of the propolis were between 0.01–1.65 μg/mL. Based on these results, propolis requires further investigation as a potential agent for the treatment of superficial mycoses.     

Alloparental feeding in Adélie penguins: why is it uncommon?

We investigated alloparental interactions and conditions which could facilitate or prevent the expression of alloparental behaviours in Adélie penguins (Pygoscelis adeliae), a long-lived seabird which nests in high-density colonies around Antarctica. Observation sessions were carried out during the crèche stage on 48 identified pairs and 50 identified chicks in a 217-nest subcolony. As the season progressed, young were fed less often by their own parents because these were increasingly absent from the breeding site and less responsive to their offspring’s solicitations. As a consequence, young and particularly those with a low body mass, coming from a two-chick brood, opted for gradually soliciting more from other adults to obtain food, preferentially those nesting in their direct vicinity. Unsuccessful breeders represented a low and constant part of the adult population and were not specifically solicited by unrelated young. Despite the increasing chick demand, only 4.1% (3 out of 73) of alloparental solicitations resulted in feeding, which is negligible compared to parental feeding. To investigate factors that could trigger the appearance of alloparental care, we carried out comparisons with king (Aptenodytes patagonicus) and emperor penguins (Aptenodytes forsteri) which represent the closest species for which data on alloparental behaviour were available. Our results show different trends to those observed in these species and three factors may explain the low occurrence of alloparental behaviour in Adélie penguins: (1) the low and constant proportion of unsuccessful breeders, (2) the absence of chick selectivity towards unsuccessful breeders, and (3) the late period of chick accessibility for potential alloparents.     

Nucleotide sequence of gene linA encoding resistance to lincosamides in Staphylococcus haemolyticus

We have determined the nucleotide sequence of gene linA in plasmid pIP855, which confers resistance to lincomycin by inactivating it in Staphylococcus haemolyticus. The gene was defined by start and stop codons and an open reading frame of 483 bp corresponding to a product with an Mr of 19020. The apparent size of the resistance-conferring protein was 21 kDa, when a minicell extract was electrophoresed in the sodium dodecyl sulfate-polyacrylamide gels. Full expression of linA was obtained both in Escherichia coli and Bacillus subtilis.     

模拟打制实验及其在丁村角页岩石器研究中的应用

模拟打制是史前考古研究中的重要实验考古方法之一,对于正确认识考古标本的类型和技术、解读当时人类的认知水平和知识积累具有不可取代的作用。本文简要回溯了模拟打制实验的发展史,并评述其应用现状。模拟打制实验在欧美有较长的发展与应用历史,但最终趋向了不同的发展方向。传统的模拟打制实验研究在欧洲得到了更加深入的继承和发展,而美国在上世纪90年代后期逐渐发展起了以定量控制、数理统计为核心的实验方法。本文以近期在山西丁村开展的角页岩模拟打制实验为例,介绍传统的模拟打制实验的基本流程和内容,包括实验的内容设计、实施及记录和分析等。本次实验结果肯定了硬锤锤击技术在丁村角页岩石核剥片和修理中的广泛应用,并在一定程度上否定了以往对使用碰砧法的推测。文章最后对模拟打制实验存在的问题和应用前景作了讨论和展望。     

Dendritic cells and cytokines in human inflammatory and autoimmune diseases

Dendritic cells (DCs) produce cytokines and are susceptible to cytokine-mediated activation. Thus, interaction of resting immature DCs with TLR ligands, for example nucleic acids, or with microbes leads to a cascade of pro-inflammatory cytokines and skewing of T cell responses. Conversely, several cytokines are able to trigger DC activation (maturation) via autocrine, for example TNF and plasmacytoid DCs, and paracrine, for example type I IFN and myeloid DCs, pathways. By controlling DC activation, cytokines regulate immune homeostasis and the balance between tolerance and immunity. The increased production and/or bioavailability of cytokines and associated alterations in DC homeostasis have been implicated in various human inflammatory and autoimmune diseases. Targeting these cytokines with biological agents as already is the case with TNF and IL-1 represents a success of immunology and the coming years will expand the range of cytokines as therapeutic targets in autoinflammatory and autoimmune pathology.     

Reciprocal influence of connexins and apical junction proteins on their expressions and functions

Membranes of adjacent cells form intercellular junctional complexes to mechanically anchor neighbour cells (anchoring junctions), to seal the paracellular space and to prevent diffusion of integral proteins within the plasma membrane (tight junctions) and to allow cell-to-cell diffusion of small ions and molecules (gap junctions). These different types of specialised plasma membrane microdomains, sharing common adaptor molecules, particularly zonula occludens proteins, frequently present intermingled relationships where the different proteins co-assemble into macromolecular complexes and their expressions are co-ordinately regulated. Proteins forming gap junction channels (connexins, particularly) and proteins fulfilling cell attachment or forming tight junction strands mutually influence expression and functions of one another.     

Distinct Biology of Kaposi’s Sarcoma-Associated Herpesvirus from Primary Lesions and Body Cavity Lymphomas

The DNA sequence for Kaposi’s sarcoma-associated herpesvirus was originally detected in Kaposi’s sarcoma biopsy specimens. Since its discovery, it has been possible to detect virus in cell lines established from AIDS-associated body cavity-based B-cell lymphoma and to propagate virus from primary Kaposi’s sarcoma lesions in a human renal embryonic cell line, 293. In this study, we analyzed the infectivity of Kaposi’s sarcoma-associated herpesvirus produced from these two sources. Viral isolates from cultured cutaneous primary KS cells was transmitted to an Epstein-Barr virus-negative Burkitt’s B-lymphoma cell line, Louckes, and compared to virus induced from a body cavity-based B-cell lymphoma cell line. While propagation of body cavity-based B-cell lymphoma-derived virus was not observed in 293 cell cultures, infection with viral isolates obtained from primary Kaposi’s sarcoma lesions induced injury in 293 cells typical of herpesvirus infection and was associated with apoptotic cell death. Interestingly, transient overexpression of the Kaposi’s sarcoma-associated herpesvirus v-Bcl-2 homolog delayed the process of apoptosis and prolonged the survival of infected 293 cells. In contrast, the broad-spectrum caspase inhibitors Z-VAD-fmk and Z-DEVD-fmk failed to protect infected cell cultures, suggesting that Kaposi’s sarcoma-associated herpesvirus-induced apoptosis occurs through a Bcl-2-dependent pathway. Kaposi’s sarcoma-associated herpesvirus isolates from primary Kaposi’s sarcoma lesions and body cavity-based lymphomas therefore may differ and are likely to have distinct contributions to the pathophysiology of Kaposi’s sarcoma.     

Large-scale production of a therapeutic protein in transgenic tobacco plants: effect of subcellular targeting on quality of a recombinant dog gastric lipase

A recombinant dog gastric lipase with therapeutic potential for the treatment of exocrine pancreatic insufficiency was expressed in transgenic tobacco plants. We targeted the protein using two different signal sequences for either vacuolar retention or secretion. In both cases, an active glycosylated recombinant protein was obtained. The recombinant enzymes and the native enzyme displayed similar properties including acid resistance and acidic optimum pH. The proteolytic maturation and the specific activity of the recombinant proteins, however, were found to be dependent on subcellular compartmentalization. Expression levels of recombinant dog gastric lipase were about 5% and 7% of acid extractable plant proteins for vacuolar retention and secretion respectively. This expression system already has allowed the production of tens of grams of purified lipase through open-field culture of transgenic tobacco plants.