We describe a simple experimental approach for delivering self-assembled monolayers (SAMs) of octadecylphosphonic acid (OPA) on many oxide surfaces using a nonpolar medium with a dielectric constant around 4 (e.g., trichloroethylene). This approach readily results in the formation of full-coverage OPA SAMs on a wide variety of oxide surfaces including cleaved mica, Si wafer, quartz, and aluminu...

Control and preventive measures for gonococcal infections are based on precise epidemiological characteristics of N. gonorrhoeae isolates. In the present study the potential utility of opa-typing and ribotyping for molecular epidemiological study of consecutive gonococcal strains was determined. Sixty gonococcal isolates were subjected to ribotyping with two restriction enzymes, AvaII and HincI...

Neisseria gonorrhoeae (GC) establishes infection at the mucosal surface of the human genital tract, most of which is lined with polarized epithelial cells. GC can cause localized as well as disseminated infections, leading to various complications. GC constantly change their surface structures via phase and antigenic variation, which has been implicated as a means for GC to establish infection ...

The immunoglobulin-like family of CD66 antigens, present on human neutrophils and epithelial cells, are used as receptors for adhesins expressed by the pathogenic Neisseriae. N. gonorrhoeae strain MS11 can express 11 isoforms of these adhesins, called opacity-related (Opa) proteins. Each MS11 Opa protein recognizes a distinct spectrum of CD66 receptors. CD66-Opa binding is mediated by the NH(2)...

The opacity (Opa) proteins mediate a variety of interactions between the bacterium Neisseria meningitidis and its human host. These interactions are thought to be of central importance in both the asymptomatic colonization of the nasopharynx and the sporadic occurrence of meningococcal disease. The receptor specificities of a limited number of Opa protein variants have been explored, but the hi...

During natural infection, gonococcal opacity proteins (Opa) undergo rapid phase variation, but how this phenomenon contributes to the virulence of the bacteria is not well understood. In the present immunomorphological study we examined the actual Opa status of individual gonococci during various stages of gonococcal infection of Chang epithelial cells, by probing ultrathin sections of infected...

Neisseria gonorrhoeae strain MS11 is able to express 11 different opacity (Opa) proteins on its outer surface. A number of these Opa proteins have been shown to function as adhesins through binding of CD66 receptors present on human cells. CD66 antigens, or carcinoembryonic antigen family members, constitute a family of glycoproteins belonging to the immunoglobulin superfamily. Opa variants rec...

OBJECTIVES To determine the relationship between occupational physical activity (OPA) and chronic disease after controlling for leisure-time physical activity (LTPA) and other risk factors. METHODS Using cycle 2.1 of the Canadian Community Health Survey, OPA energy expenditure was derived. The association of OPA with any self-reported chronic disease, heart disease or diabetes was determined ...

Oil palm ash (OPA), a bio-agricultural waste from oil palm mills, was subjected to high-energy ball milling for 30 h and was converted into a nano-structured material. The nano-structured OPA was characterized for its particle size and crystallinity index by using Transmission Electron Microscopy (TEM) and X-ray Diffraction (XRD) analysis. The crystallite size obtained from TEM and XRD was foun...

Bordetella pertussis is the causative agent of pertussis (whooping cough). Despite high vaccination coverage, pertussis remains a significant disease in many countries. Besides vaccination, transient carriage of Bordetella spp. or other cross-reacting organisms adds to the immunity against pertussis. However, the various immunological mechanisms conferring protection remain largely unknown. In ...