Inhibition of Bordetella pertussis filamentous hemagglutinin-mediated cell adherence with monoclonal antibodies

Abstract Filamentous hemagglutinin (FHA), a 220-kDa protein located on the surface of Bordetella pertussis , is one of the major cell adhesins of this bacterium. We have produced three hybridoma cell lines that express monoclonal antibodies (mAbs) against FHA: X3C, X3E and X4B. The anti-FHA mAbs X3C and X3E reacted with 220-kDa FHA protein bands on Western blots. The mAb X4B, which reacted with FHA in ELISA, did not bind to FHA in a Western blot assay. All three mAbs seemed to be directed to the same epitope or to epitopes in close proximity as suggested by competition ELISAs. All three mAbs were able to inhibit the adherence of Chinese hamster ovary cells to purified FHA, and they could also inhibit the FHA-mediated agglutination of goose red blood cells. The attachment of B. pertussis to epithelial cell monolayers was inhibited by the mAb X3C. These antibodies are very useful probes to identify the presence of FHA in bordetellae species and in clinical reagents such as pertussis vaccines, and to characterize the functional domains of this important bacterial adhesin.     

Gap junction structures: Analysis of the x-ray diffraction data

Models for the spatial distribution of protein, lipid and water in gap junction structures have been constructed from the results of the analysis of X-ray diffraction data described here and the electron microscope and chemical data presented in the preceding paper (Caspar, D. L. D., D. A. Goodenough, L. Makowski, and W.C. Phillips. 1977. 74:605-628). The continuous intensity distribution on the meridian of the X-ray diffraction pattern was measured, and corrected for the effects of the partially ordered stacking and partial orientation of the junctions in the X-ray specimens. The electron density distribution in the direction perpendicular to the plane of the junction was calculated from the meridional intensity data. Determination of the interference function for the stacking of the junctions improved the accuracy of the electron density profile. The pair-correlation function, which provides information about the packing of junctions in the specimen, was calculated from the interference function. The intensities of the hexagonal lattice reflections on the equator of the X-ray pattern were used in coordination with the electron microscope data to calculate to the two-dimensional electron density projection onto the plane of the membrane. Differences in the structure of the connexons as seen in the meridional profile and equatorial projections were shown to be correlated to changes in lattice constant. The parts of the junction structure which are variable have been distinguished from the invariant parts by comparison of the X-ray data from different specimens. The combination of these results with electron microscope and chemical data provides low resolution three- dimensional representations of the structures of gap junctions.     

Regurgitation and choke in rats

Male and female F344 rats choked on fecal pellets and regurgitant during the course of two long-term experiments. Each study involved feeding standard and high bulk diets containing 10% wood cellulose or 10% chrysotile asbestos fiber. Choke deaths occurred at all stages of the experiments. A total of 36 of 774 (4.6%) rats in the two studies died of choke. Females died of choke more frequently (26/382 or 6.8%) than did males (10/392 or 2.6%). Rats on high bulk diets were affected more frequently (33/571 or 5.8%), especially those on 10% asbestos diet (26/311 or 8.4%, than rats consuming standard diet (3/190 or 1.6%). The reason for the difference between females and males was not determined. Although choke may be related to some characteristics of high nonnutritive bulk feed fed in pellet form, the higher risk for females even on standard diet (3/95 or 3.2%) than for males (0/95) indicated that more than one factor operated in the etiology of these events.     

Microbiological quality of frozen breaded fish and shellfish products.

A survey was made of the microbiological quality of seven frozen, breaded, precooked fish and shellfish products and of frozen, breaded, uncooked shrimp at the retail level. Geometric mean aerobic plate counts per gram (and number of units examined) were as follows: fish sticks, 8,300 (1,539); fish cakes, 5,600 (1,378); crab cakes, 4,900 (1,226); scallops, 1,700 (1,392); clams, 450 (1,384); haddock, 15,000 (1,306); fish in fish and chips dinner, 7,200 (1,485); and uncooked shrimp, 220,000 (1,462). Geometric mean coliform, Escherichia coli, and Staphylococcus aureus counts for all eight products ranged from 1 to 10/g.     

Manganese and zinc toxicity thresholds for mountain and Geyer willow

Information on the heavy metal toxicity thresholds of woody species endemic to the western United States is lacking but critical for successful restoration of contaminated riparian areas. Manganese (Mn, 50-10,000 mg l(-1)) and zinc (Zn, 100-1000 mg l(-1)) toxicity thresholds were determined for Geyer (Salix geyeriana Anderss.) and mountain (S. monticola Bebb) willow using a sand-culture technique. The lethal concentration (50%) values were 3117 and 2791 mg Mn l(-1) and 556 and 623 mg Zn l(-1) for Geyer and mountain willow, respectively. The effective concentration (50%) values for shoots were 2263 and 1027 mg Mn l(-1) and 436 and 356 mg Zn l(-1) for Geyer and mountain willow, respectively. Shoot tissue values did not increase with increasing treatment concentrations. However, metals in the roots did increase consistently in response to the treatments. Metal levels in the shoot tissues were low for Zn (65-139 mg kg(-1)) and moderate for Mn (1300-2700 mg kg(-1)). Geyer and mountain willow have good resistance to Mn, possibly due to evolution in hydric soils with increased Mn availability, and may be useful for phytostabilization of soils with high levels of available Mn. Both species were affected to a greater degree by Zn as compared to Mn, but still exhibited good resistance and should be useful in remediating sites with at least moderate levels of available Zn. Based on the thresholds evaluated, Geyer willow had greater resistance to both Mn and Zn as compared to mountain willow, especially at lower concentrations in which growth of Geyer willow was actually stimulated.     

The role of nitric oxide in cancer

Nitric oxide (NO) is a pleiotropic regulator, critical to numerous biological processes, including va-sodilatation, neurotransmission and macrophage-mediated immunity. The family of nitric oxide synthases (NOS) comprises inducible NOS (iNOS), endothelial NOS (eNOS), and neuronal NOS (nNOS). Interestingly, various studies have shown that all three isoforms can be involved in promoting or inhibiting the etiology of cancer. NOS activity has been detected in tumour cells of various histogenetic origins and has been associated with tumour grade, proliferation rate and expression of important signaling components associated with cancer development such as the oestrogen receptor. It appears that high levels of NOS expression (for example, generated by activated macrophages) may be cytostatic or cytotoxic for tumor cells, whereas low level activity can have the opposite effect and promote tumour growth. Paradoxically therefore, NO (and related reactive nitrogen species) may have both genotoxic and angiogenic pro