The influence of selected steroid hormones on the physicochemical behaviour of DPPC liposomes

The physicochemical properties of DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) liposomes used for topical application are pharmaceutically important. Therefore the aim of our study was to establish rapid and efficient methods for the exact characterisation of the physicochemical properties of extruded DPPC liposomes containing low concentration (0.5%, w/w) of different, therapeutically interesting steroid hormones, named 17-beta-estradiol, cpa (cyproterone acetate) and finasteride. In a first step it could be shown that all drugs influenced the liposome size and changed the zeta potential compared to the placebo formulations. Our further analytical strategy was to use micro-calorimetry and ATR-FTIR (Fourier transformed infrared spectroscopy), two powerful and non-destructive methods to confirm the drug incorporation into the liposomes by proving interactions between the phospholipids and the steroids. Thereby it was even possible to localize the location of interaction. The characteristic phase transition temperatures of the phospholipid were decreased by the hormones which was detected by micro-DSC (differential scanning calorimetry). The results of the ATR-FTIR measurements indicated shifts of the specific lipid peaks, the C=O stretching bands and PO(2)(-) antisymmetric double stretching band, in the gel and liquid crystalline phase. A polar as well as a non-polar interaction could be proven. It could be shown that the investigated steroid hormones changed the physical properties of the phospholipid bilayers.     

Population dynamics of the harmful diatom Eucampia zodiacus Ehrenberg causing bleachings of Porphyra thalli in aquaculture in Harima-Nada, the Seto Inland Sea, Japan

The diatom Eucampia zodiacus Ehrenberg is one of the harmful diatom species which indirectly cause bleachings of Nori (Porphyra thalli) in aquaculture through competitive utilizing of nutrients (especially nitrogen) and resultant nutrient depletion in water columns during the bloom events. The seasonal changes in environmental factors, cell density and cell size of E. zodiacus were investigated for 4 years (April 2002–December 2005) to understand the population ecology of this diatom in Harima-Nada, the eastern part of the Seto Inland Sea, Japan. Vegetative cells of E. zodiacus were usually detected year-round. Total cell densities of E. zodiacus annually peaked from mid-February to early April, and high cell densities were observed in the whole water columns during the bloom-period. Nutrient concentrations decreased with the increase of cell density of E. zodiacus, and low nutrients concentrations continued throughout the E. zodiacus bloom-period. The average cell size (length of apical axis) of E. zodiacus populations ranged from 10.8 μm to 81.2 μm, and the restoration of cell size occurred once in autumn every year just after reaching the minimum cell size. In addition, its great seasonal regularity was confirmed by the decrease and restoration of its cell size through 4-year study period. Temperature and nutrients were suitable in autumn for the growth of E. zodiacus, its blooms never occur in that season. These results strongly suggest that E. zodiacus did not have a resting stage, and it spends autumn for size restoration and starts to bloom thereafter in Harima-Nada in winter and spring, causing fishery damage to Nori aquaculture by resulting nutrient deprivation.     

Anti-salmonella properties of kefir yeast isolates: An in vitro screening for potential infection control

The rise of antibiotic resistance has increased the need for alternative ways of preventing and treating enteropathogenic bacterial infection. Various probiotic bacteria have been used in animal and human. However, Saccharomyces boulardii is the only yeast currently used in humans as probiotic. There is scarce research conducted on yeast species commonly found in kefir despite its claimed potential preventative and curative effects. This work focused on adhesion properties, and antibacterial metabolites produced by Kluyveromyces lactis and Saccharomyces unisporus isolated from traditional kefir grains compared to Saccharomyces boulardii strains. Adhesion and sedimentation assay, slide agglutination, microscopy and turbidimetry assay were used to analyze adhesion of Salmonella Arizonae and Salmonella Typhimurium onto yeast cells. Salmonella growth inhibition due to the antimicrobial metabolites produced by yeasts in killer toxin medium was analyzed by slab on the lawn, turbidimetry, tube dilution and solid agar plating assays. Alcohol and antimicrobial proteins production by yeasts in killer toxin medium were analyzed using gas chromatography and shotgun proteomics, respectively. Salmonella adhered onto viable and non-viable yeast isolates cell wall. Adhesion was visualized using scanning electron microscope. Yeasts-fermented killer toxin medium showed Salmonella growth inhibition. The highest alcohol concentration detected was 1.55%, and proteins with known antimicrobial properties including cathelicidin, xanthine dehydrogenase, mucin-1, lactadherin, lactoperoxidase, serum amyloid A protein and lactotransferrin were detected in yeasts fermented killer medium. These proteins are suggested to be responsible for the observed growth inhibition effect of yeasts-fermented killer toxin medium. Kluyveromyces lactis and Saccharomyces unisporus have anti-salmonella effect comparable to Saccharomyces boulardii strains, and therefore have potential to control Salmonella infection.     

Power-law versus exponential distributions of animal group sizes

There has been some confusion concerning the animal group size: an exponential distribution was deduced by maximizing the entropy; lognormal distributions were practically used; as power-law decay with exponent 3/2 was proposed in physical analogy to aerosol condensation. Here I show that the animal group-size distribution follows a power-law decay with exponent 1, and is truncated at a cut-off size which is the expected size of the groups an arbitrary individual engages in. An elementary model of animal aggregation based on binary splitting and coalescing on contingent encounter is presented. The model predicted size distribution holds for various data from pelagic fishes and mammalian herbivores in the wild.     

Inhibition of glycogen phosphorylase (GP) by CP-91,149 induces growth inhibition correlating with brain GP expression

The role of glycogenolysis in normal and cancer cells was investigated by inhibiting glycogen phosphorylase (GP) with the synthetic inhibitor CP-91,149. A549 non-small cell lung carcinoma (NSCLC) cells express solely the brain isozyme of GP, which was inhibited by CP-91,149 with an IC(50) of 0.5 microM. When treated with CP-91,149, A549 cells accumulated glycogen with associated growth retardation. Treated normal skin fibroblasts also accumulated glycogen with G1-cell cycle arrest that was associated with inhibition of cyclin E-CDK2 activity. Overall, cells expressing high levels of brain GP were growth inhibited by CP-91,149 correlating with glycogen accumulation whereas cells expressing low levels of brain GP were not affected by the drug. Analyses of 59 tumor cell lines represented in the NCI drug screen identified that every cell line expressed brain GP but the profile was dominated by a few highly GP expressing cell lines with lower than mean GP-a enzymatic activities. The correlation program, COMPARE, identified that the brain GP protein measured in the NCI cell lines corresponded with brain GP mRNA expression, ADP-ribosyltransferase 3, and colony stimulating factor 2 receptor alpha in the 10,000 gene microarray database with similar correlation coefficients. These results suggest that brain GP is present in proliferating cells and that high protein levels correspond with the ability of CP-91,149 to inhibit cell growth.     

Hydrocarbon distribution and colony odour homogenisation in <Emphasis Type="Italic">Pachycondyla apicalis</Emphasis>

Summary Within and between individuals hydrocarbon (HC)-circulation was studied in Pachycondyla apicalis workers, using radioactive labeling. Newly synthesized HCs occurred both in the PPG and on the epicuticle in appreciable amounts, lesser quantities were found in the crop. The front basitarsal brush contained a greater amount of radiolabeled HCs than could be predicted from its surface area, suggesting preferential secretion to these organs. We propose that the newly synthesized HCs are secreted primarily to the front basitarsal brushes and are thereafter either distributed throughout the body surface, or cleared via the PPG and the alimentary canal.Using labeled HCs as a model, we tracked the time-dependent dispersion of cuticular lipids among 11 workers, one of which was prelabeled for 24 hours. Distribution among the recipients became progressively uniform, reaching near homogenization between 5–10 days. The mean HCs transfer of P. apicalis to the PPG was substantially lower compared to that of Camponotus fellah or Aphaenogaster senilis. In contrast, transfer to the cuticle in this species was superior. We attribute the low transfer to the PPG to the inefficacy of passive body contact characteristic of P. apicalis, as opposed to trophallaxis and/or allogrooming that typify the other two species. The higher occurrence of radiolabeled HCs in P. apicalis cuticle can be attributed to their accumulation in the basitarsal brushes. The impact of cuticular lipid transfer and formation of uniform colony odour, as opposed to the maintenance of an idiosyncratic caste-specific composition, are discussed.Received 5 September 2002; revised 17 January 2003; accepted 10 February 2003.     

Anticancer activity of Hemsleya amabilis extract

Hemsleya amabilis extract is derived from the medicinal herb Hemsleya amabilis, which has long been used to treat cancer and many other conditions. The underlying mechanism is not clear. To investigate Hemsleya amabili's anticancer activity, we have treated different types of cancer cells including human astrocytoma U87 cells, breast cancer cells MDA-MB-231and Jurkat cells with Hemsleya amabilis extract. This agent significantly inhibited tumor cell growth and colony formation at various concentrations. When astrocytoma cells were seeded in the presence of Hemsleya amabilis extract at very low concentrations, cell spreading was greatly inhibited. Hemsleya amabilis extract also promoted tumor cell death in all the tested cell lines, but with varied sensitivities. Apoptotic assays with Annexin V staining demonstrated that Hemsleya amabilis extract induced astrocytoma cell apoptosis at different concentrations.     

不同水分条件下春小麦种群中个体大小不整齐性及遗传学分析不同水分条件下春小麦种群中个体大小不整齐性及遗传学分析

 种群内个体大小不整齐性是种群数量结构的主要指标。本文研究了不同水分条件下,3个品种春小麦种群个体大小不整齐性的建立及变化规律。对春小麦种群不整齐性的遗传学分析表明：遗传结构与随机环境修饰对种群数量结构形成的相对重要性,因水分条件不同而异。种群不整齐性在自然选择中的作用可用下列简单模型表示：CSo＝SH×hSH2 CSo：自然选择强度;SH：大小不整齐性;hSH2：不整齐性的遗传力。     

Semi-quantitative colony immunoassay for determining and optimizing protein expression in Saccharomyces cerevisiae and Escherichia coli

This work describes a quick semi-quantitative colony immunoassay (QSCI) method for immunoblot detection of intracellularly expressed proteins in both yeast and bacterial cells. After induction of protein expression, only 4.5 h is required for cell breakage, protein detection, and data analysis. This protocol was used to screen and unambiguously identify Saccharomyces cerevisiae cells efficiently overexpressing glutathione S-transferase (GST)-tagged Yih1 in addition to cells expressing the myc-tagged large 297-kDa Gcn1 protein. In addition, the method was used to identify Escherichia coli cells efficiently expressing His6-tagged Yih1 and a GST-tagged Gcn1 fragment, respectively. The protocol allows the use of both epitope-specific and protein-specific antibodies. The same colony immunoassay can also be used to determine the minimal concentration of inducing agent sufficient for induction of optimal protein expression (e.g., galactose for yeast, isopropyl β-d-1-thiogalactopyranoside [IPTG] for E. coli). To our knowledge, this is the first report on a rapid low-cost procedure that allows the calibration of inducing agent on solid medium.