Silicic acid reacts with insulin, albumin and amorphous nylon over a wide pH range but monolayers are tanned only near pH 6. Tanning requires (i) the combination of silicic acid with the protein or polyamide, and (ii) further polymerization of the adsorbed silicic acid. The roles of ionic links and hydrogen bonds are discussed.

No. 47oaJanuary 23, 1960 NATURE 237 molecular weight (10 5 -10 6 ) isotactic polystyrene.The spectrum shown was obtained from isotactic polystyrene in deuterated chloroform using a 'Varian V-4300' 40•00-Mc./s. spectrometer. A similar spectrum was obtained in thionyl chloride . Like Bovey et al., we observed no r esolution of chain protons for commercial atactic polystyrene . Neither was resolution observed for high molecular weight (10 5 ) polystyrene prepared using n -butyl-lithium initiator nor for benzene-insoluble polystyrene obtained via Alfin sodiwn alkyl catalysis•,•.

Silicic acid reacts with monolayers of collagen and gelatin between pH 3 and 9. The films are tanned in this pH range and the force/area curves after a second compression are not identical with those relating to the first compression. Tanning is probably due to the cross-linking of chains or parts of protein chains rather than to the polymerization of silicic acid beneath the film, as is the case with globular proteins.The previous paper described studies on the interaction of silicic acid with films of several proteins, which are normally globular. This communication discusses the results obtained in a parallel study of the interaction of silicic acid with films of collagen and its degradation product, gelatin. The fibrous proteins are not easy to study because it is difficult to bring them into solution without alteration. Native collagen is insoluble in most solvents. A fraction of the collagen of tendon is soluble in acetic acid but very dilute solutions only can be prepared. Gelatin is degraded and is water-soluble. Hide powder collagen has been spread from anhydrous formic acid but it is stated to resemble gelatin rather than collagen. The properties of films of these three proteins have been examined. E X P E R I M E N T A L MATERIALSThe apparatus and the method of preparation of substrates are described in the previous paper. Results were plotted as force/area curves from which the surface pressures at an arbitrary area (0.5 m2/mg) were read off. These values were plotted against the substrate pH to give force/pH curves. Force/pH curves are preferable to area/pH curves when the films are highly compressible. powder collagen (14.7 % N) were kindly provided by the British Leather Manufacturers' Research Association. The gelatin was spread from a solution (0.05 %) in 0.1 % aqueous ethanol and the hide powder collagen from anhydrous formic acid, on to spreading areas of 8.0 m2/mg (temp. 25").TENDON COLLAGEN.-TendOn collagen was prepared from rat tails. The tendon was stripped from the tail, washed in normal saline, then treated with 0.1 % trypsin in normal saline for 24 h at 37". The tendon was washed with water then with 10 % NaCl to remove proteins other than collagen. Fat and other surface-active substances were removed by ether and ethanol, the tendon finally being washed in acetone and dehydrated in vacuaThe dry tendon was then placed in 0.1 % acetic acid and allowed to dissolve for 12 h or more before the residue was filtered off. The filtrate containing 0.018 mg/ml gave satisfactory monolayers. GELATIN AND HIDE POWDER COLLAGEN.-Gelathl (iSOelectIk point 5.0) and hide R E S U L T S GELATIN AND HIDE POWDER COLLAGEN The films of gelatin and hide powder collagen behaved in an almost identical manner. CONTROL SUBSTRATES (1 M NaCl + 0-0125 M Na2C03)All the films of gelatin and hide powder collagen were reversibly compressible (see, e.g., fig. 1, curve A). There was little variation with pH of the force required to maintain the film at a constant area ( fig. 2 and 3). No maximum was observed at the isoelectri...

Asa portion of its continuing study of hydrocarbon properties and molecular structure American Petroleum Institute Research Project 42 has synthesized and determined the physical properties of more than 80 alkylbenzenes and alkylcyclohexanes (10).Most recently four polyalkylbenzenes and polyalkylcyclohexanes of a structural type not previously studied have been synthesized (1). These new

Human nasal colonization with Staphylococcus aureus sets the stage for subsequent systemic infection. The mechanisms responsible for colonization are not fully understood. This study characterizes S. aureus adhesion to nasal mucosa in vitro and observes the interaction of S. aureus with mucin. S. aureus showed significantly higher binding to mucin during stationary phase in comparison to log-phase cells. Adherence of S. aureus srtA mutant to mucin was not significantly different from wild-type, thus Srt A shows no influence on S. aureus interaction with mucin. Adherence to mucin was saturable in a dose- and time-dependent fashion. Biotin–labelled mucin bound to surface protein (55 kDa) of cell wall extracted S. aureus which is encoded by the sbi gene. These data suggest that adherence factors are present on the surface of S. aureus such as sbi. Purified recombinant Sbi was prepared and the mucin binding capacity of the protein was tested by ELISA. In order to determine the function of specific domains of Sbi in adhesion, Sbi constructs with, without the IgG-domain and with B2-glycoprotein domain were expressed on the surface of E. coli BL21(DE3). The expression of Sbi with the B2-glycoprotein domain on the surface adhesion, emphasizing the role of Sbi in mucin adhesion. A profound binding effect was observed with Sbi incubated in wells coated with host mucin. Therefore, it is proposed to investigate a novel interaction of S. aureus to host mucin in order to control S. aureus nasal colonization.