Identification of 3-deoxy-lyxo-2-heptulosaric acid in the core region of lipopolysaccharides from Rhizobiaceae

A 3-deoxy-2-heptulosaric acid (DHA), very probably with the lyxo-configuration, was identified in the R-core region of lipopolysaccharides from nodulating strains of Rhizobium leguminosarum, Rhizobium meliloti and from all three biovars of the phytopathogenic Agrobacterium tumefaciens. Its structure could be deduced from the fragmentation pattern of the corresponding alditol acetates obtained after reduction of the 2-keto and the 1.7-carboxy groups by sodium borohydride or sodium borodeuteride. DHA in lipopolysaccharide was not destroyed by periodate and is therefore not in a terminal position. Two DHA-containing oligosaccharides, namely glucosyl (1----4)-3-deoxy-2-heptulosaric acid and rhamnosyl-rhamnosyl-(1----5)-3-deoxy-2-heptulosaric acid could be tentatively identified by mass spectrometric methods amongst the products of mild acidic hydrolysis of lipopolysaccharides of Rhizobium leguminosarum strain 24. The two types of non-nodulating mutants of Rhizobium leguminosarum included in this study did not contain 3-deoxy-2-heptulosaric acid.     

Physical anthropological approaches to aging

The field of gerontology is remarkably diverse; yet there has been relatively little investigation of physical anthropological issues in aging research. This review explores gerontologic topics of actual and/or potential interest to physical anthropologists. The evolution of aging presents a theoretical dilemma in that postreproductively expressed traits may be outside the influence of natural selection. The physiological changes of aging comprise a diversified mosaic of physical deterioration as would be expected from an evolutionary model. Studies of prehistoric aging are limited to estimating lifespan, which may not be indicative of rate of aging. Considerable attention has been devoted to body composition and aging, and notable findings include a loss of lean tissue with age and relatively constant (though redistributing) fat mass. Osteoporosis is a major problem of aging in females, as is tooth loss in both sexes. The study of variation in rates of aging is only beginning, and a number of approaches to measuring biological age in adulthood are presented. Determining the associations of lifestyle, economic, and nutritional status with biological age may reveal sources of variation in rates of aging and may be of practical importance.     

CHANGES IN WEIGHT,NITROGEN ACCUMULATION,RESPIRATION AND PHOTOSYNTHESIS DURING GROWTH AND DEVELOPMENT OF SEEDS AND PODS OF PHASEOLUS VULGARIS

The growth and development of pods and seeds of Phaseolus vulgaris are described by the following parameters: fresh and dry weight, length, ratio of fresh weight to length and nitrogen content. Pod and seed development are independent and sequential. Pod photosynthesis contributes only marginally to pod development, but may be significant in refixing CO₂ released in respiration. Pods and seeds do not seem to act simply as competing sinks. Nitrogen accumulation in the seeds begins only when it has ceased in the pods. Ways in which regulation may be achieved are discussed. Manipulation of nitrogen fertilization to enhance seed growth is suggested.     

Diel plasma melatonin profile in a cyclostome, the river lamprey

Plasma melatonin levels in adult river lampreys Lampetra fluviatilis , sampled during their upstream migration showed a pronounced diel profile, with high levels during the night and lower levels during the day, showing that a cyclostome, in common with other vertebrates, exhibits such a diel plasma profile.     

Purification and characterisation of a growth factor from porcine bone

A growth factor was extracted from porcine bone matrix by demineralisation and purified by heat and acid treatment, hydroxyapatite chromatography and gel filtration under dissociative conditions and reverse-phase HPLC. Using the mitogenic response of osteoblast-progenitor cells from embryonic chicken, a mitogenic activity was purified 3000-fold. The mitogenic protein thus purified shows an apparent molecular mass of 13.5 kDa in both the nonreduced and reduced form on sodium dodecyl sulfate/polyacrylamide gel electrophoresis. The mitogenic activity is sensitive to proteinase K, dithiothreitol, and resistant to DNAse, RNase, heat (70 degrees C) and pH (3-10). The factor stimulates the proliferation of osteoblast-progenitor cells from embryonic chick at a concentration of 1 ng/ml. It is active on cells from skin, periosteum and sternum and has no or little activity on cells of the calvaria, intestine or kidney of embryonic chick or on mouse AKR-2B/Balb c/3T3 cell line.     

Role of I-region gene products in T cell activation. I. Stimulation of T lymphocyte proliferative responses by subcellular membrane preparations containing Ia alloantigens

A model system has been developed for exploring the requirements for activation of T cells by subcellular forms of Ia alloantigen. Lymph node cells from mice recently primed subcutaneously with viable allogeneic cells show strong proliferative responses in vitro to membrane preparations derived from cells bearing the appropriate I-region-encoded glycoproteins. This stimulation shows kinetics characteristic of a secondary response, with a peak at 24 to 48 hr. Primary responses to alloantigen-bearing membranes are weak or absent under these conditions. The predominant cell type involved in the secondary response is the Lyt-1+ T lymphocyte, and the major antigenic stimulus is the I-A subregion-encoded Ia glycoprotein. Syngeneic Ia+ accessory cells do not appear necessary for activation to occur. Detergent solubilized reconstituted membrane vesicles also will stimulate primed T lymphocytes to respond by proliferation. The applications of this approach to the study of T cell recognition of antigen and the role of nonspecific lymphokines in T cell triggering are discussed.     

Initial Commitment to Pre-Exposure Prophylaxis and Circumcision for HIV Prevention amongst Indian Truck Drivers

Studies of HIV prevention interventions such as pre-exposure prophylaxis (PREP) and circumcision in India are limited. The present study sought to investigate Indian truck-drivers initial commitment to PREP and circumcision utilizing the AIDS Risk Reduction Model. Ninety truck-drivers completed an in-depth qualitative interview and provided a blood sample for HIV and HSV-2 testing. Truck-drivers exhibited low levels of initial commitment towards PREP and even lower for circumcision. However, potential leverage points for increasing commitment were realized in fear of infecting family rather than self, self-perceptions of risk, and for PREP focusing on cultural beliefs towards medication and physicians. Cost was a major barrier to both HIV prevention interventions. Despite these barriers, our findings suggest that the ARRM may be useful in identifying several leverage points that may be used by peers, health care providers and public health field workers to enhance initial commitment to novel HIV prevention interventions in India.     

Monoclonal antibodies to monoamine oxidase B and another mitochondrial protein from human liver.

A monoclonal antibody has been generated to human liver monoamine oxidase (MAO) B by fusion of mouse myeloma cells with spleen cells from a mouse immunized with a mixture of semi-purified MAO A and MAO B. The antibody, 3F12/G10, an immunoglobulin G1, reacts with its antigen in cryostat sections of human liver, showing an intracellular particulate distribution as demonstrated by immunoperoxidase staining. The antibody indirectly precipitates [3H]pargyline-labelled human MAO B both from liver and platelet extracts but fails to precipitate MAO A from liver extracts. The antibody does not recognise rat liver MAO B, showing that the determinant is not universally expressed on MAO B. The antibody has no effect on the catalytic activity of MAO B. Other monoclonal antibodies were generated but they are directed to a protein with a subunit Mr of 54 000, a contaminant of the MAO preparation. One of these antibodies, A8/C2, an IgG2a, reacts with the same protein in both rat and human liver extracts.