Candida albicans, the most common human fungal pathogen, is particularly problematic for immunocompromised individuals. The reversible transition of this fungal pathogen to a filamentous form that invades host tissue is important for its virulence. Although different signaling pathways such as a mitogen-activated protein kinase and a protein kinase A cascade are critical for this morphological transition, the function of polarity establishment proteins in this process has not been determined. We examined the role of four different polarity establishment proteins in C. albicans invasive growth and virulence by using strains in which one copy of each gene was deleted and the other copy expressed behind the regulatable promoter MET3. Strikingly, mutants with ectopic expression of either the Rho G-protein Cdc42 or its exchange factor Cdc24 are unable to form invasive hyphal filaments and germ tubes in response to serum or elevated temperature and yet grow normally as a budding yeast. Furthermore, these mutants are avirulent in a mouse model for systemic infection. This function of the Cdc42 GTPase module is not simply a general feature of polarity establishment proteins. Mutants with ectopic expression of the SH3 domain containing protein Bem1 or the Ras-like G-protein Bud1 can grow in an invasive fashion and are virulent in mice, albeit with reduced efficiency. These results indicate that a specific regulation of Cdc24/Cdc42 activity is required for invasive hyphal growth and suggest that these proteins are required for pathogenicity of C. albicans.

This study investigated the potential application of allyl isothiocyanate (AITC) for the disinfection of water by examining the bactericidal effects of this compound against inoculated Escherichia coli in autoclaved, de-chlorinated tap water and against the natural microbiota (heterotrophic plate count bacteria, HPCs) in a surface water. Bacteriostatic trials for AITC demonstrated growth inhibition against E. coli in tryptone soy broth, with AITC concentrations of 47.5, 63.3 and 126.6 mg/l inhibiting growth over two hours of contact time and 505.5 mg/l achieving complete growth inhibition for seven days. These AITC concentrations were then used to assess the bactericidal effect of AITC in water matrices, through which at least a 1.22-log10 reduction of both E. coli and HPCs was achieved in all trials, and up to a maximum of 2.93-log10 reduction of E. coli with 126.6 mg/l of AITC and two hours of contact time. AITC was consistently less effective against the HPCs in the surface water compared to the inoculated E. coli in tap water. Under the conditions that were tested, AITC was unable to reduce the HPC values below 100 CFU/ml, the World Health Organization guideline for safe drinking water, suggesting that AITC should not be used as a potable water disinfectant on its own; however, there may be applications for AITC as a biocide for non-potable water storage or treatment.

UV disinfection reactors are an effective and economic means to inactivate oocysts of the protozoan parasite Cryptosporidium in drinking water. Cryptosporidiosis outbreaks can occur as a result of filter breakthrough following increased oocyst loading of treatment processes (Bouchier, 1998). Oocysts are resistant to commonly used chlorine-based disinfectants and therefore filter failure can result in outbreaks of cryptosporidiosis (Korich et al., 1990). Low and medium pressure UV disinfection has been demonstrated to be effective at reducing oocyst infectivity at economic UV doses, and hence UV reactors have become increasingly common as drinking water treatments for inactivating oocysts and other waterborne pathogens

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Primary Mill Residue • During 1986, Wisconsin primary wood-using mills (except the pulp, flakeboard, and particleboard mills) generated 744,000 green tons of coarse residue, 466,000 green tons of fine residue, and 332,000 green tons of bark. • Most of the residue was used: 98 percent of the coarse, 94 percent of the fine, and 90 percent of the bark residue. • By type of residue, the dominant use was in fiber products for coarse residue, in miscellaneous products (such as mulch, livestock bedding, and poultry litter) for fine residue, and in industrial fuel for bark. • Counties each producing more than 50,000 green tons of coarse and fine residue in 1986 were Forest, Marinette, Shawano, Vilas, and La Crosse. APPENDIX Study Methods Data for this publication come from canvassing (with a formal questionnaire) all the known primary woodusing mills that use Wisconsin logs and bolts. The study was a cooperative effort of the Wisconsin Department of Natural Resources (WDNR) and the North Central Forest Experiment Station (NCFES). The Michigan Department of Natural Resources supplied information for their primary mills using Wisconsin wood during another cooperative study Industrial roundwood products.-Saw logs, pulpwood, veneer logs, poles, commercial posts, piling, cooperage logs, industrial fuelwood, shaving bolts, lath bolts, charcoal bolts, and chips from roundwood used for pulp or board products. Pulpwood includes logs and bolts used to manufacture pulp, particleboard, and waferboard. Industrial roundwood production.-The quantity of industrial roundwood harvested in a geographic area. Industrial roundwood receipts.-The quantity of industrial roundwood received in a geographic area, regardless of the geographic source. Logging residue.-The unused portions of all trees cut or killed by logging. Includes unused tops and limbs. Does not include bark. Primary wood-using mills.-Mills receiving roundwood or chips from roundwood for processing into products. Primary wood-using mill residue.-Wood materials (coarse and fine) and bark generated at manufacturing plants from roundwood processed into principal products. These residues include wood products (byproducts) obtained incidental to production of principal products and wood materials not utilized for some product. Roundwood.-Logs, bolts, or other round sections cut from trees (including chips from roundwood). Standard cord.-A stack of wood bolts (or the equivalent) encompassing 128 cubic feet of wood, bark, and air space. A cord of pulpwood contains 79 cubic feet of wood and 49 cubic feet of bark and air space. A cord of fuelwood contains 70 cubic feet of wood and 58 cubic feet of bark and air space. Timberland.-Forest land producing or capable of producing crops of industrial wood and not withdrawn from timber utilization. (Note: Areas qualifying as timberland are capable of producing more than 20 cubic feet per acre per year of annual growth when managed. Currently inaccessible and inoperable areas are included except

A new method was developed for estimating the ultraviolet (UV) dose that is delivered by operating UV disinfection reactors in drinking water treatment plants, through the quantification of pyrimidine (i.e. thymine-thymine) dimer formation in the DNA of indigenous microorganisms (i.e. no organisms spiked into the water). An enzyme-linked immuno-sorbent assay (ELISA) was applied to the indigenous DNA that was extracted from water samples that were collected from drinking water treatment plants and from lab tap water and exposed to collimated beam UV doses, resulting in a near-linear relationship between the assay response and UV dose. The new method has the potential to provide a relatively quick, sampling-based means of monitoring the UV dose being delivered by operating UV reactors in drinking water treatment plants, without the need to spike a biodosimeter or actinometer into the water.