Lipid A-associated proteins from periodontopathogenic bacteria induce interleukin-6 production by human gingival fibroblasts and monocytes

Abstract The aim of this study was to determine whether lipid A-associated proteins (LAP) from two periodontopathogenic species of bacteria were able to stimulate interleukin-6 (IL-6) release from human gingival fibroblasts and myelomonocytic cells. LAP and lipopolysaccharide (LPS) were extracted from Porphyromonas gingivalis and Prevotella intermedia and added to cultures of human gingival fibroblasts and mono-mac-6 monocytic cells. Release of IL-6 into the culture supermatants was determined by ELISA. LAP and LPS from Por. gingivalis , but not from Prev. intermedia , stimulated IL-6 release from both cell types in a dose-dependent manner although LPS was less potent than LAP in inducing IL-6 release from the fibroblasts. IL-6 was detectable in cultures of both cell types following stimulation with LAP from Por. gingivalis at a concentration as low as 10 ng/ml. In response to LAP from Prev. intermedia , IL-6 was produced by mono-mac-6 cells but not by fibroblasts. Our results show that bacterial cell wall components other than LPS can induce IL-6 release from cells of the periodontium in vitro. The production of such potent immunomodulatory agents in vivo may contribute to the connective tissue breakdown characteristic of chronic periodontitis.     

Expression domains of the Cf1a POU domain protein during Drosophila development

We have used antibodies directed against a unique portion of the Drosophila POU domain protein Cfla to localize its sites of expression in developing embryos. Cfla protein is first detected during germ band extension in the tracheal placodes and in the midline mesectoderm cells. Tracheal expression continues throughout embryonic development, especially in the main longitudinal tracheal trunks. Additional sites of high Cfla expression are in the anterior portion of the hindgut, the roof of the stomodeum, a subset of central nervous system cells, the oenocytes, and the ring gland. In addition, Cfla expression was localized in embryos mutant for several loci involved in determining fate along the midline of the CNS and the tracheal system. Cfla midline cell expression is dependent on proper single-minded gene function, and Cfla either regulates or acts in parallel to the genes pointed and rhomboid during midline CNS and tracheal development.     

Genetic regulation of gibberellin deactivation in Pisum

The regulation of gibberellin (GA) deactivation was examined using the sin (slender) mutation in the garden pea (Pisum sativum L.). This mutation blocks the deactivation of GA₂₀, the precursor of the bioactive GA₁. Firstly, crosses were made to combine sin with the GA biosynthesis mutations na, lhⁱ and le-3. The combination sin na produced a novel phenotype, with long (‘slender’) basal internodes and extremely short (‘nana’) upper internodes. In contrast, the double mutant sin lhⁱ was phenotypically dwarf. The mutation sin causes an accumulation of GA₂₀ in maturing seeds, and this was unaffected by na, since the na mutation is not expressed in seeds. In contrast, lhⁱ seeds did not accumulate GA₂₀, since lhⁱ imposes an early block on GA biosynthesis. Secondly, the effects of sin on several steps in GA deactivation were investigated. In maturing seeds, the mutation sin blocks two steps in GA₂₀ metabolism, namely, GA₂₀ to GA₂₉, and GA₂₉ to GA₂₉-catabolite. In the vegetative plant, on the other hand, sin blocked the step GA₂₀ to GA₂₉, but not GA₂₉ to GA₂₉-catabolite; the steps GA₂₀ to GA₈₁ and GA₂₀ to GA₁ were also not impaired in this mutant. It is clear that the effects of sin, like those of na, are strongly organ-specific. The presence of separate enzymes for the steps GA₂₀ to GA₂₉ and GA₂₉ to GA₂₉-catabolite was suggested by the observation that GA₈ inhibited the latter step, but not the former, and by the inability of GA₂₀ and GA₂₉ to inhibit each other's metabolism. It is suggested that the Sin gene may be a regulatory gene controlling the expression of two structural genes involved in GA deactivation.     

Perilymphatic Fistula—A Definitive and Curable Cause of Vertigo Following Head Trauma

Vertigo or disequilibrium occurring in patients after concussive and nonconcussive head trauma may be due to a pathologic perilymphatic fistula from the inner ear through the oval and round window areas of the middle ear. Of 33 patients who had successful grafting of the fistulous area at middle ear exploration, 32 had resolution of vertigo, and 12 of 23 who had an associated hearing loss had improved hearing. Perilymphatic fistulas associated with vertigo and hearing loss after head trauma can be diagnosed with great certainty and are surgically curable in the great majority of cases. Patients with post-concussive syndrome, whose symptoms include vertigo or disequilibrium, should have a thorough otologic evaluation for the possibility of a perilymphatic fistula.     

Sequential hydration of dry proteins: a direct difference IR investigation of sequence homologs lysozyme and alpha- lactalbumin

Direct difference ir spectra are presented as a function of hydration for lysozyme and α-lactalbumin, and detailed sequential hydration molecular events identified. Despite the strong sequence homology between the two proteins, and their expected conformational similarity, the hydration behaviour of the polar groups is different for the two proteins. Using a Hill-type analysis, we conclude that the acid groups ionize and hydrate rapidly and noncooperatively in both proteins, consistent with the known (lysozyme) and postulated (α-lactalbumin) surface chemistry. The polar group hydration shows a clear cooperativity, which is quantitatively different in the two proteins. Complementary work suggests this cooperativity relates to a hydration-induced “loosening up” of the lysozyme conformation at about 55 mol water/mol protein. α-Lactalbumin appears to “open up” more easily for hydration than does lysozyme, consistent with its lower stability against thermal and acid denaturation.     

Intragroup agonistic behavior in captive groups of the common marmosetCallithrix jacchus jacchus

Agonistic behavior was observed in five captive groups of the monogamous monkey Callithrix jacchus jacchus,which normally produces twin offspring every 5 months. Fighting is first recorded when twins are aged 5–10 months. These “twin fights” determine differences in status between combatants that can be detected 5 months later. From what is known of the social behavior of the species, it is postulated that an individual’s twin is its most serious rival and that early fighting is advantageous because injury is minimal while the animal retains its milk dentition. In contrast to twin fights, aggression between same-sex juveniles and adults does not involve long fights and probably serves to reinforce preexisting differences in status. It often results in forcing a group member to the periphery, and therefore, its main function may be to drive mature, same-sexed individuals out of the group. Apart from the relationship between twins, status within the family group is age related and not normally determined by aggression.     

An experimental analysis of social interaction in the common marmoset (Callithrix jacchus jacchus)

Adult and juvenile common marmosets were introduced to unfamiliar conspecifics individually and in whole groups. In introductions using animals of the same sex, adults were mutually hostile unless they were related or socially familiar; juveniles behaved submissively to adults and little aggression was observed between juveniles. In introductions using animals of the opposite sex, males of all ages solicited females but females did not reciprocate. When whole groups were introduced, in two experiments most of the elder group members behaved aggressively and younger animals did not interact frequently; but in a third experiment, in which the adult males were related, little aggression was observed and younger animals behaved amicably. It is argued that the behavioral reactions shown by individual marmosets are related to territorial hostility and that the behavior of juveniles to adults may aid assimilation of younger animals into new groups.     

Outer membrane protein P of Pseudomonas aeruginosa: regulation by phosphate deficiency and formation of small anion-specific channels in lipid bilayer membranes.

A new major outer membrane protein, P, was induced in Pseudomonas aeruginosa PAO1 upon growth in medium containing 0.2 mM or less inorganic phosphate. Studies with media containing different levels of phosphate and with mutants of PAO1 suggested that protein P was coregulated with alkaline phosphatase and phospholipase C. Protein P was substantially purified and shown to form sodium dodecyl sulfate-resistant oligomers on polyacrylamide gels. The incorporation of purified protein P into artificial lipid bilayers resulted in an increase of the membrane conductance by many orders of magnitude. Single-channel experiments demonstrated that protein P channels were substantially smaller than all previously studied porins from P. aeruginosa and enteric bacteria, with an average single-channel conductance in 1 M NaCl of 0.25 nS. The protein P channel was apparently not voltage induced or regulated. The results of single-channel conductance experiments, using a variety of different salts, allowed a minimum channel diameter estimate of 0.7 nm. Furthermore, from these results it was concluded that the protein P channel was highly specific for anions. Zero-current potential measurements confirmed that protein P was at least 30-fold more permeable for Cl- than for K+ ions. The possible biological role of the small, anion-specific protein P channels in phosphate uptake from the medium is discussed.     

The adverse effects of HEPES, TES, and BES zwitterion buffers on the ultrastructure of cultured chick embryo epiphyseal chondrocytes

Chick embryo epiphyseal chondrocytes cultured in media containing HEPES, TES, and BES zwitterion buffers, used in combination or independently, consistently developed cytoplasmic vacuoles. This cytoplasmic vacuolation was resolved when the zwitterion buffered media was replaced by media containing bicarbonate:CO2 enriched air buffer. Vacuoles were infrequent or absent in cultures grown in bicarbonate:CO2 enriched air. Chondrocytes with an established extracellular matrix showed less vacuolation than fibroblastlike and polygonal shaped cells that lacked such a matrix. The granular endoplasmic reticulum and Golgi dictyosomes of zwitterion buffered chondrocytes were distended and contained a flocculent amorphous material. Cytoplasmic vacuoles (0.5 to 3.0 micron diam) formed by the fusion and intracellular accumulation of Golgi vesicles and vacuoles also contained a flocculent material enhanced by ruthenium red. Membrane bound extracellular vacuoles containing ruthenium red stained proteoglycan aggregates were common in the extracellular matrix of zwitterion buffered cultures but were generally absent from bicarbonate treated cultures. Electron dense calcium deposits seemed much larger and more numerous in the presence of zwitterion buffers. It is suggested that HEPES, TES, and BES buffers, used alone or in combination, may adversely affect cell membrane systems, and thus the transport or secretory mechanisms operative in cultured chondrocytes, or both, resulting in vacuole formation and the intracellular accumulation of synthesized export material. Although the mechanism by which HEPES, TES, and BES induce these changes remains unclear, the use of zwitterion buffers in biological preparations should be treated with caution.     

Somatic Expression and Autosomal Inheritance of Phosphoglycerate Kinase B in Kangaroos

The PGK-B isozyme, currently known as PGK-2 in the mouse nomenclature, is the predominant PGK isozyme in mammalian sperm. In many species it is detectable only in sperm, in spermatogenic testes and in epididymides containing sperm. In this paper, we provide evidence that some kangaroo species express low PGK-B activity in somatic tissues, in addition to high activity in testes. Three kangaroo species, M. rufogriseus, M. robustus and M. giganteus, exhibit polymorphism of PGK-B. Breeding data support the hypothesis of autosomal co-dominant inheritance, as is the case in mice. Population data for the three polymorphisms are discussed. PGK-B is not detectable in somatic tissues or spermatogenic testis extracts of monotreme mammals, birds or lizards; it is probably restricted to therian mammals.