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SalmonellaEnteritidis (SE) has been a major foodborne concern associated with poultry and poultry products. Direct-fed microbials (DFM), such as Bacillus subtilisstrains,and mannan-oligosaccharides (MOS) added into poultry feed have emerged as an alternative approach to antimicrobials to reduce Salmonellacolonization in chickens. This study was conducted to evaluate the effect of a synbiotic feed additive product (BacPack Q1+1) combining a selected Bacillus subtilisstrain and yeast cell wall-derived MOS on SE colonization in the ceca of Hy-line W36 pullets. Day-old chicks were raised in cage units and orally challenged at 3 wk-of-age with a nalidixic acid resistant SE strain at a dose of 1.6 × 109colony forming units (CFU) per bird. SE colonization was assessed by enumeration of SE in cecal pouches at 7, 10 and 13 days postinfection (dpi). SE was not detectable in the ceca of 68% of synbiotic supplemented pullets compared to 36% of the controls at 13 dpi (P = 0.049). The findings of this study suggest that synbiotic combinations of DFM and prebiotics could be a useful tool for reducing the prevalence of Salmonellain layer chickens.

Gcn4, a yeast transcriptional activator that promotes the expression of amino acid and purine biosynthesis genes, is rapidly degraded in rich medium. Here we report that SCF(CDC4), a recently characterized protein complex that acts in conjunction with the ubiquitin-conjugating enzyme Cdc34 to degrade cell cycle regulators, is also necessary for the degradation of the transcription factor Gcn4. Degradation of Gcn4 occurs throughout the cell cycle, whereas degradation of the known cell cycle substrates of Cdc34/SCF(CDC4) is cell cycle regulated. Gcn4 ubiquitination and degradation are regulated by starvation for amino acids, whereas the degradation of the cell cycle substrates of Cdc34/SCF(CDC4) is unaffected by starvation. We further show that unlike the cell cycle substrates of Cdc34/SCF(CDC4), which require phosphorylation by the kinase Cdc28, Gcn4 degradation requires the kinase Pho85. We identify the critical target site of Pho85 on Gcn4; a mutation of this site stabilizes the protein. A specific Pho85-Pcl complex that is able to phosphorylate Gcn4 on that site is inactive under conditions under which Gcn4 is stable. Thus, Cdc34/SCF(CDC4) activity is constitutive, and regulation of the stability of its various substrates occurs at the level of their phosphorylation.

Swi5 and Ace2 are cell cycle-regulated transcription factors that activate expression of early G(1)-specific genes in Saccharomyces cerevisiae. Swi5 and Ace2 have zinc finger DNA-binding domains that are highly conserved, and the two proteins bind to the same DNA sequences in vitro. Despite this similarity in DNA binding, Swi5 and Ace2 activate different genes in vivo, with Swi5 activating the HO gene and Ace2 activating CTS1 expression. In this report we have used chimeric fusions between Swi5 and Ace2 to determine what regions of these proteins are necessary for promoter-specific activation of HO and CTS1. We have identified specific regions of Swi5 and Ace2 that are required for activation of HO and CTS1, respectively. The Swi5 protein binds HO promoter DNA cooperatively with the Pho2 homeodomain protein, and the HO specificity region of Swi5 identified in the chimeric analysis coincides with the region of Swi5 previously identified that interacts with Pho2 in vitro. Swi5 and Ace2 also activate expression of a number of other genes expressed in G(1) phase of the cell cycle, including ASH1, CDC6, EGT2, PCL2, PCL9, RME1, and SIC1. Analysis of the Swi5/Ace2 chimeras shows that distinct regions of Swi5 and Ace2 contribute to the transcriptional activation of some of these other G(1)-regulated genes.

The potency and specificity of immunotoxins consisting of monoclonal antiidiotype conjugated to the ribosome-inactivating protein, saporin, have been evaluated in the treatment of guinea pig L2C B lymphocytic leukemia. The immunotoxins were therapeutically much more effective than their parent antibodies. Their specificity reflected that of their antiidiotype component. Although the leukemia emerged eventually in most animals treated with these conjugates, most of the cells showed altered Ig expression, which rendered them resistant to the therapy. Commonly, the emerging cells had lost mu heavy chain production, leaving them negative for intracellular, surface, and secreted IgM, but still positive for lambda light chain production. In addition, a minor group of L2C variants was identified in a protocol designed to detect mutants at very low frequency: here the cells were exposed in vitro to immunotoxin and, while still viable as judged by dye-exclusion, inoculated in large numbers into animals. In tumor that emerged under these circumstances, the majority of cells were again immunoglobulin-negative; however a minority exhibited IgM with an altered idiotype (Idiotope-loss variants), rendering them unreactive with immunotoxin. Immunotherapy with unmodified anti-Id antibody alone does not reveal these variants, and we suggest it is the increased selective force exerted by the highly potent immunotoxins that allow these minor nonreactive populations to emerge.

Summary: This study was undertaken to determine whether immunostaining with the monoclonal antibodies Ki-67 and MIB1 is of use in the distinction of tuboendometrial metaplasia from endocervical adenocarcinoma and adenocarcinoma in situ (AIS) on formalin-fixed, paraffin-embedded tissue. Tissue sections from 100 cases (52 normal endocervix, 27 endocervical tuboendometrial metaplasia, eight endocervical AIS, 13 endocervical adenocarcinoma) were stained with Ki-67 and MIB1 after microwave pretreatment in citrate buffer. Ki-67 and MIB1 labelling indices (LIs) were calculated in each case by determining the percentage of positive-staining nuclei. Five hundred nuclei were counted in each case. Significant differences in Ki-67 and MIB1 LIs existed between the adenocarcinoma group and the tuboendometrial metaplasia group and between the AIS group and the tuboendometrial metaplasia group. No significant differences existed between the adenocarcinoma and AIS groups. Over all groups, the Ki-67 LI was consistently lower than the MIB1 LI. The results indicate that immunohistochemical staining with Ki-67 and MIB1 may be of use in the often difficult histological distinction of tuboendometrial metaplasia from malignant endocervical glandular lesions.