EFFECT OF AN OXYGEN-REDUCING MEMBRANE FRACTION ON HELICOBACTER PYLORI

The emerging gastric pathogen Helicobacter pylori is an oxygen-sensitive fastidious microaerophile. Culturability of this organism is rapidly lost in oxygen levels present in the atmosphere due to its morphological transformation into a viable but not culturable state. The effect of the Oxyrase^TM system of oxygen-reducing membrane fragments on H. pylori was evaluated at levels ranging from 0.1 to 0.6 Units/mL in Brucella broth supplemented with 5% horse serum. Duplicate sets of Oxyrase^TM dilutions inoculated with H. pylori were incubated at 35C aerobically and microaerobically. At these Oxyrase^TM levels, a logarithmic loss of H. pylori viability was evident in the aerobic cultures. The inoculum remained recoverable for 24 h in the presence of Oxyrase^TM, whereas recovery of inoculum in untreated broth was greatly reduced after 8 h of aerobic incubation, and the organism was unrecoverable after 24 h. Oxyrase^TM-containing broth cultures of H. pylori incubated microaerobically showed a similar drop in viable counts for the first 48 h of incubation; however, at the lower levels of Oxyrase^TM, some cells survived, and resumed logarithmic growth at 96 h. To explore the effects of short term aerobic incubation in the presence of 0, 0.005, 0.05, and 0.5 Units Oxyrase^TM, cultures were examined microscopically after 4, 8, and 24 h. In the Oxyrase^TM-containing broths, <90% of the cells exhibited rod shape morphology after 8 h, whereas in the untreated broth, most cells appeared coccoid. After 24 h, all cells exhibited coccoid morphology.     

Conceptual Styles, Culture Conflict, and Nonverbal Tests of Intelligence

Conceptual styles are rule-sets for the selection and organization of sense data. Two mutually incompatible conceptual styles are identified—relational and analytic. Relational and analytic methods of conceptual organization appear to have been developed and reinforced in shared-function and formally organized primary groups, respectively, as socialization settings. Each style affects its carrier's ability to deal effectively with the alternate kind of group process requirements. A distinction is drawn between culture conflict and related notions of deprivation and culture difference. When the conceptual styles used between individuals and groups are mutually incompatible, culture conflict may be said to exist, whether or not the other phenomena are also present. It is found that highly relational pupils in the analytic school environment represent this type of culture conflict regardless of their native ability or the variety and relevance of their experience backgrounds. This difficulty is not obviated by developing context-free situations. Item solution requirements for common nonverbal tests of intelligence, for instance, focus directly on expertise in using the analytic rule-set as a measure of intelligence. Their culture bias has, thus, not been reduced but has been moved to a higher level of abstraction. Conceptual rule-sets also affect the assimulation of experience content. They determine to a great extent the number and nature of contextual attributes that will appear relevant to individuals. In addition, because a wide variety of social and psychological behaviors are meaningful only when they follow from these rule-sets, conceptual styles contribute to the formation of logically derived normative systems.     

Human alveolar macrophage fibronectin: synthesis, secretion, and ultrastructural localization during gelatin-coated latex particle binding

Human pulmonary alveolar macrophages synthesized and secreted several characteristic high molecular weight proteins for at least 7 d in vitro. Immunoprecipitates of medium and cell lysates from metabolically labeled cultures with specific anti-human plasma fibronectin IgG contained one major labeled polypeptide of molecular weight 440,000 (unreduced) or 220,000 (reduced). An identical polypeptide in conditioned medium from radiolabeled macrophages bound specifically to gelatin-Sepharose, demonstrating that alveolar macrophages synthesized and secreted a molecule immunologically and functionally similar to fibronectin. Fibronectin was the major newly synthesized and secreted polypeptide of freshly harvested alveolar macrophages. Pulse-chase experiments revealed that newly synthesized fibronectin was rapidly secreted into medium, approximately 50 percent appearing by 1 h and 80 percent by 8 h. Immunoperoxidase staining using antifibronectin F(ab’)(2)-peroxidase conjugates revealed the majority of immunoreactive fibronectin to be intracellular, localized to endoplasmic reticulum and Golgi apparatus. No extracellular matrix fibronectin was visualized, and cell surface staining was rarely seen, usually appearing only at sites where cells were closely apposed and not at sites of macrophage-substrate attachment. Similar immunostaining of fibroblast cultures revealed cell surface-associated fibrillar fibronectin. Ultrastructural localization of fibronectin during binding and phagocytosis of gelatin-coated and plain latex particles revealed fibronectin only on gelatin-latex beads and at their cell binding sites. Neigher plain latex beads nor their cell membrane binding sites stained for fibronectin. These results demonstrate that fibronectin is a major product of human alveolar macrophages, is rapidly secreted, and is localized at cell membrane binding sites for gelatin-coated particles. In view of the known binding properties of fibronectin, it may serve as an endogenous opsonic factor promoting the binding of staphylococcus, denatured collagen, fibrin, or other macromolecules to macrophages in the lower respiratory tract.     

Phylogenetic screening of the human genome: identification of differentially hybridizing repetitive sequence families

The phi-screen, a method of phylogenetic screening, can be employed to detect repetitive sequence families that differentially hybridize between closely related species. Such differences may involve sequence divergence or variations in copy number, including total presence versus absence of a family of repeated DNA. We present the results of a phi-screen comparing the human genome to that of the prosimian, Galago crassicaudatus. Three human repetitive families that are divergent or not present in galago have been detected. One of these families is described in detail; it is similar among the anthropoids but is present in a lower copy number and/or divergent form in prosimians. The family is clearly related to the transposon-like human element (THE) described by Paulson et al. (1985). THEs have long terminal repeats reminiscent of retroviruses but are unique in that they have no sequence similarity to known mammalian retroviruses. The sequence of a solo long terminal repeat, found unassociated with THE internal sequence, is presented. This family member, THE p2, is bordered by a 5-bp target-site repeat and is interrupted by the insertion of an Alu element. A solo THE element sequenced by Wiginton et al. (1986) contains an insertion of Alu at precisely the same position as does THE p2.