Enhancing the fungicidal activity of amphotericin B via vacuole disruption by benzyl isothiocyanate,a cruciferous plant constituent

Amphotericin B (AmB), a typical polyene macrolide antifungal agent, is widely used to treat systemic mycoses. In the present study, we show that the fungicidal activity of AmB was enhanced by benzyl isothiocyanate (BITC), a cruciferous plant-derived compound, in the budding yeast, Saccharomyces cerevisiae. In addition to forming a molecular complex with ergosterol present in fungal cell membranes to form K⁺-permeable ion channels, AmB has been recognized to mediate vacuolar membrane disruption resulting in lethal effects. BITC showed no effect on AmB-induced plasma membrane permeability; however, it amplified AmB-induced vacuolar membrane disruption in S. cerevisiae. Furthermore, the BITC-enhanced fungicidal effects of AmB significantly decreased cell viability due to the disruption of vacuoles in the pathogenic fungus Candida albicans. The application of the combinatorial antifungal effect of AmB and BITC may aid in dose reduction of AmB in clinical antifungal therapy and consequently decrease side effects in patients. These results also have significant implications for the development of vacuole-targeting chemotherapy against fungal infections.     

Failure of testicular development associated with a rearrangement of 9p24.1 proximal to the SNF2 gene

In 46,XY individuals, testes are determined by the activity of the SRY gene (sex-determining region Y), located on the short arm of the Ychromosome. The other genetic components of the cascade that leads to testis formation are unknown and may be located on the Xchromosome or on the autosomes. Evidence for the existence of several loci associated with failure of male sexual development is indicated by reports of 46,XY gonadal dysgenesis associated with structural abnormalities of the Xchromosome or of autosomes (chromosomes9, 10, 11 and 17). In this report, we describe the investigation of a child presenting with multiple congenital abnormalities, mental retardation and partial testicular failure. The patient had a homogeneous de novo 46,XY,inv dup(9)(pter→p24.1::p21.1 →p23.3::p24.1→qter) chromosome complement. No deletion was found by either cytogenetic or molecular analysis. The SRY gene and DSS region showed no abnormalities. Southern blotting dosage analysis with 9p probes and fluorescent in situ hybridisation data indicated that the distal breakpoint of the duplicated fragment was located at 9p24.1, proximal to the SNF2 gene. We therefore suggest that a gene involved in normal testicular development and/or maintenance is present at this position on chromosome 9. Received: 20 January 1997 / Accepted: 5 November 1997     

A new method for mechanical dechorionation of ascidian eggs

Pasteur pipets were prepared with constricted tips of such diameter that unfertilized Ciona intestinalis (L.) eggs could be held immobile while their chorions were lanced open with a tungsten needle. Eggs were pretreated with double-strength seawater to increase the space between egg and chorion. Eighty-five percent of the eggs dechorionated in this way developed normally after fertilization in regular seawater.     

Purification and characterization of glyoxalase I from Pseudomonas putida

Glyoxalase I was purified to apparent homogeneity from Pseudomonas putida. The enzyme was a monomer with a molecular weight of 20,000. The enzyme was most active at pH 8.0. The Km values for methylglyoxal and 4,5-dioxovale-rate are 3.5 mM and 1.2 mM, respectively. Contrary to the case of eukaryotic enzymes, chelating agents showed little inhibitory effects on the enzyme activity. Among the metal ions tested, Zn++ specifically and completely inhibited the activity of the enzyme at a millimolar level. The properties of bacterial glyoxalase I were quite different from mammalian and yeast enzymes.     

Views,landmarks, and routes: how do desert ants negotiate an obstacle course?

The Australian desert ant Melophorus bagoti often follows stereotypical routes through a cluttered landscape containing both distant panoramic views and obstacles (plants) to navigate around. We created an artificial obstacle course for the ants between a feeder and their nest. Landmarks comprised natural objects in the landscape such as logs, branches, and tussocks. Many ants travelled stereotypical routes home through the obstacle course in training, threading repeatedly the same gaps in the landmarks. Manipulations altering the relations between the landmarks and the surrounding panorama, however, affected the routes in two major ways. Both interchanging the positions of landmarks (transpositions) and displacing the entire landmark set along with the starting position of the ants (translations) (1) reduced the stereotypicality of the route, and (2) increased turns and meanders during travel. The ants might have used the entire panorama in view-based travel, or the distal panorama might prime the identification and use of landmarks en route. Despite the large data set, both options (not mutually exclusive) remain viable.     

Chemical, physicochemical and spectrophotometric properties of crystalline chlorophyll-protein complexes from Lepidium virginicum L

Two kinds of water-soluble chlorophyll-protein complexes were prepared from leaves of Lepidium virginicum L., one (CP661) from the plant cultivated in a green house from seeds collected near Mono Lake, CA, and the other (CP-663) from a plant collected at Narashino, Chiba, Japan, by ammonium sulfate fractionation followed by column chromatography on DEAE-cellulose and Sephacryl S-200. The chlorophyll . proteins were further purified by crystallization. CP661 has absorption peaks at 661, 468, 439, 419, 380, 339 and 272 nm. CP663 had absorption peaks at 663, 469, 438, 419, 379, 338 and 272 nm. Estimated molecular weights were 78 000 for CP661 and 80 000 for CP663 by gel filtration chromatography and 83 000 for CP661 and 107 000 for CP663 by an equilibrium sedimentation method. 1 mol chlorophyll . protein contained 4 mol chlorophyll a and b with ratios of 1.0 in CP661 and 1.6 to 1.9 in CP663, but no carotenoids. These characters are different from those of chlorophyll-protein complexes which are prepared from the thylakoid membranes of chloroplasts with detergents.     

Fragile X expression in thymidine-prototrophic and auxotrophic human-mouse somatic cell hybrids under low and high thymidylate stress conditions

Expression of the fragile X site fra(X)(q27.3) was studied in thymidine-prototrophic and auxotrophic human-mouse somatic cell hybrids. In these cells, low thymidylate stress, achieved by 5-fluoro-2'-deoxyuridine (FdU) treatment and by limiting the exogenous supply of thymidine (dT), induced fragile X expression. High thymidylate stress, produced by supplying excess amounts of dT, was also effective in inducing fragile X expression, even in a hybrid clone that retained a fragile X chromosome as the only human chromosome; addition of deoxycytidine (dC) completely abolished this effect. In contrast, 5-bromo-2'-deoxyuridine (BrdU) did not induce fragile X expression. Cell-cycle analysis of BrdU-deprived thymidine-auxotrophic hybrid cells indicated that one round of DNA replication under thymidylate stress conditions is sufficient for fragile X expression. Our results suggest that the expression is an intrinsic property of the fragile site itself, which is believed to be composed of replicon clusters with pyrimidine-rich DNA sequence(s).     

The effectiveness of constructed wetland for treatment of woodwaste leachate

Percolation of rainfall through woodwaste piles leaches natural chemicals from the wood residuals that can have adverse impacts on the environment. A study was conducted on a woodwaste storage site, adjacent to the Lower Fraser River, near Mission, BC, Canada. The objective of this research was to evaluate the effectiveness of constructed wetland for treatment of this woodwaste leachate. The leachate was characterized by high oxygen demand, tannin and lignin, and volatile fatty acids (VFAs), but low pH and nutrients. Diluted leachate passed through six pilot-scale wetland cells, four planted with cattail (Typha latifolia) and two unplanted controls, with a hydraulic retention time of 7 days and an average depth of 40 cm. Nutrient addition and pH adjustments were made to improve contaminant removal. Reductions in contaminants were consistently achieved, with average removals for BOD, COD, VFAs and tannin and lignin of 60, 50, 69 and 42%, respectively. Climatic conditions had an impact on the performance of the constructed wetland. Further operation of the system will help to elucidate the seasonal fluctuations. Aging of the constructed wetland system increased the treatment performance.     

Factors associated with whole carcass condemnation rates in provincially-inspected abattoirs in Ontario 2001-2007: implications for food animal syndromic surveillance

Background  

Ontario provincial abattoirs have the potential to be important sources of syndromic surveillance data for emerging diseases of concern to animal health, public health and food safety. The objectives of this study were to: (1) describe provincially inspected abattoirs processing cattle in Ontario in terms of the number of abattoirs, the number of weeks abattoirs process cattle, geographical distribution, types of whole carcass condemnations reported, and the distance animals are shipped for slaughter; and (2) identify various seasonal, secular, disease and non-disease factors that might bias the results of quantitative methods, such as cluster detection methods, used for food animal syndromic surveillance.