Candida albicans is an important human pathogen that causes systemic infections, predominantly among populations with weakened immune systems. The morphological transition from the yeast to the hyphal state is one of the key factors in C. albicans pathogenesis. Owing to their location at the host-pathogen interface, the cell wall and associated proteins are of interest, especially with respect to the yeast to hyphal transition. This study entailed the proteomic analysis of differentially regulated proteins involved in this transition. The protein profiles of C. albicans DTT/SDS-extractible proteins and the cyanogen bromide (CNBr)/trypsin-extractable proteins of a cell wall-enriched fraction from yeast and hyphae were compared. In total, 107 spots were identified from the DTT/SDS-extractible cell wall-enriched fraction, corresponding to 82 unique proteins. Of these DTT/SDS-extractible proteins, 14 proteins were upregulated and 10 were downregulated in response to hyphal induction. Approximately 6-9% of total cell wall-protein-enriched fraction was found to be resistant to DTT/SDS extraction. Analysis of the DTT/SDS-resistant fraction using a CNBr/trypsin extraction resulted in the identification of 29 proteins. Of these, 17 were identified only in the hyphae, four were identified only in the yeast, and eight were identified in both the yeast and hyphae.

High concentrations of specific catechins [epigallocatechin gallate (EGCG), epigallocatechin (EGC) and epicatechin gallate (ECG)] inhibit the proliferation of many different cancer cell lines. The aim of this work was to determine if low concentrations of catechins with and without 4-hydroxytamoxifen (4-OHT) co-treatment would cause significant cytotoxicity in estrogen receptor-positive (ERalpha+) and -negative (ERalpha-) human breast cancer cells. Therefore, MCF-7, T47D, MDA-MB-231 and HS578T cells were incubated with EGCG, EGC or ECG (5-25 microM) individually and in combination with 4-OHT for 7 days. Cell number was determined by the sulforhodamine B cell proliferation assay. As single agents, none of the catechins were cytotoxic to T47D cells, while only EGCG (20 microM) elicited cytotoxicity in MCF-7 cells. Additionally, no benefit was gained by combination treatment with 4-OHT. ERalpha- human breast cancer cells were more susceptible as all three catechins were significantly cytotoxic to HS578T cells at concentrations of 10 microM. In this cell line, combination with 4-OHT did not increase cytotoxicity. However, the most striking results were produced in MDA-MB-231 cells. In this cell line, EGCG (25 microM) produced a greater cytotoxic effect than 4-OHT (1 microM) and the combination of the two resulted in synergistic cytotoxicity. In conclusion, low concentrations of catechins are cytotoxic to ERalpha- human breast cancer cells, and the combination of EGCG and 4-OHT elicits synergistic cytotoxicity in MDA-MB-231 cells.

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The identification of genes associated with colonization and persistence of Helicobacter pylori in the gastric mucosa has been limited by the lack of robust animal models that support infection by strains whose genomes have been completely sequenced. Here we report that an interleukin-12 (IL-12)-deficient mouse (IL-12 ؊/؊ p40 subunit knockout in C57BL/6 mouse) is permissive for infection by a motile variant (KE88-3887) of The Institute For Genomic Research-sequenced strain (KE26695) of H. pylori. The IL-12-deficient mouse was also more permissive for colonization by the mouse-colonizing Sydney 1 strain of H. pylori than were wild-type C57BL/6 mice. Differences in colonization efficiency were demonstrated by mouse challenge with SS1 strains containing loss-of-function mutations in two genes (hspR and hrcA), whose products negatively regulate several heat shock genes. Helicobacter pylori colonizes the gastric mucosa of humans, producing a chronic gastritis that may remain asymptomatic for many years. In about 10% of individuals, more severe disease manifestations will occur such as duodenal and gastric ulcers, atrophic gastritis, and intestinal metaplasia, all risk factors for gastric cancer (20,40,42). The remarkable ability of H. pylori to establish lifelong infections is not well understood but likely involves evasion or modulation of host immune responses as well as adaptation (through mutation and selection) to the unique physiology of each individual host (3). In addition, different disease pathologies seem to correlate with particular H. pylori genotypes, with strains containing the cagassociated pathogenicity island and cagA gene (cytotoxinassociated gene) and vacA (vacuolating cytotoxin) correlating with more severe disease (11,14,39). There is much genetic diversity in these genes and in others such as the restriction modification genes (9) among strains from different geographic regions and people of different ethnicities (1, 10, 13). The evaluation of genetic diversity among strains and identification of genes associated with severity of infection have generally been hampered by the lack of good animal models (9,25,36).Robust animal models of infection are also a necessary component in the discovery process for new therapeutics or the evaluation of vaccine candidates (12,23,47). While several animal models have been developed, these models are limited to a few animal-adapted strains (9,22,36) or support only transient infection (25). Mouse-adapted strains such as the Sydney 1 strain (SS1), Hp1, and a few others are difficult to manipulate genetically (37) and usually require high infectious doses in order to establish infection (36). In such mouse models requiring high colonization thresholds, many genes scored as necessary for colonization may be dispensable in a more permissive animal. Another limitation of existing mouse-colonizing strains is that systematic whole-genome approaches to the study of virulence determinants cannot be performed, as the genomes of mouse-colonizing strains have not been se...