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The sporulation inhibitory gene spi in the pock-forming conjugative plasmid pSA1.1 of Streptomyces azureus was introduced into cells via a high or low copy number vector to examine the effect of gene dosage on the growth of Streptomyces lividans TK24 as a host. In transformants carrying a high spi copy number, nutrient mycelial growth was inhibited, as was morphological differentiation from substrate mycelium to aerial mycelium on solid media. The degree of inhibition depended on the spi gene dosage, but the presence of pSA1.1 imp genes, which encode negative repressor proteins for spi, relieved the inhibition. Confocal images of Spi tagged with enhanced green fluorescent protein in cells on solid media revealed that spi expression was initiated at the time of elongation of substrate mycelium, that its expression increased dramatically at septation in aerial hyphae, and that the expression was maximal during prespore formation. Expression of spi covered the whole of the hyphae, and the level of expression at the tip of the hyphae during prespore formation was about sixfold greater than during substrate mycelial growth and threefold greater than during aerial mycelial growth. Thus, localized expression of spi at particular times may inhibit sporulation until triggering imp expression to repress its inhibitory effects. [ABSTRACT FROM AUTHOR]

The article details a study which investigated if induction of systemic inflammation accelerates the development of Sjögren's syndrome (SS) in genetically susceptible mice. The study treated female mice with either Freund's incomplete adjuvant (IFA) or phosphate buffered saline (PBS). The mice were killed at different time points and underwent sialadenitis and salivary gland-infiltrating cells tests. It concluded that generalized inflammatory stimuli can accelerate the development of SS-like disease.

The mouse submandibular gland (SMG) is important organ for embryonic development, and branching morphogenesis is regulated by many molecules containing transcription factors. Real-time reverse transcriptase polymerase chain reaction revealed that the expression of Brachyury increased in the SMG and peaked between E12.5–E13.5, concomitant with the early stage of branching morphogenesis. The expression of Brachyury in SMG rudiments between E12.5–E13.5 was confirmed by western blotting. In addition, fibronectin and Btbd7 (regulated by fibronectin), which are both essential for cleft formation, were expressed strongly during the same period. The Sox2 and Wnt3a , which regulate cell growth, were also expressed strongly during E12.5–E13.5. On the other hand, cleft formation and branching morphogenesis was suppressed by knockdown of Brachyury gene, suggesting that Brachyury plays a central role in regulating cell growth and cleft formation in early-stage embryonic mouse salivary gland development. [ABSTRACT FROM AUTHOR]

Objectives: Mikulicz’s disease (MD) was considered to be a subtype of Sjögren’s syndrome (SS), based on histopathological similarities. However, recent studies have indicated that patients with MD show high serum IgG4 concentration, and suggested that MD is one of “IgG4-related disease” and distinguishable from SS. Therefore, we clinically and histopathologically examined the disease states of MD and SS in detail. Materials and methods: Twenty patients with Mikulicz’s disease and 18 with SS were comparatively studied to determine clinical characteristics in MD patients. Results: Sialography in MD patients did not show the “apple-tree sign” typically seen in SS. Serologically, high serum IgG4 levels but not anti-SS-A or anti-SS-B antibodies were observed in MD. SS showed lymphocytic infiltration of various subsets with atrophy or severe destruction of the acini, while MD showed selective infiltration of IgG4+ plasma cells with hyperplastic germinal centers and mild acini destruction. Corticosteroid treatment of MD reduced IgG and IgG4 levels and improved salivary function. A negative correlation between disease duration and increasing rate of salivary flow was observed in MD. Conclusions: These results suggested that the pathogenesis of MD might be different from those of SS. Clinical Relevance: early diagnosis and treatment of MD is important for the improvement of salivary function. [ABSTRACT FROM AUTHOR]

Protein phosphatase 1 (PP1) and protein phosphatase 2A (PP2A) are major members of the protein serine/threonine phosphatase families. We have identified PP1 and PP2A as interacting partners of PRIP (phospholipase C-related but catalytically inactive protein), a protein isolated in our laboratory. We first investigated the interaction of PRIP with two phosphatases, using purified recombinant proteins. PRIP immobilized on beads pulled down the catalytic subunits of both PP1 and PP2A, indicating that the interactions were in a direct manner, and the binding of PP1 and the binding of PP2A to PRIP were mutually exclusive. Site-directed mutagenesis experiments revealed that the binding sites for PP1 and PP2A on PRIP were not identical, but similar. Phosphorylation of PRIP by protein kinase A (PKA) resulted in the weakened binding of PP1, but not PP2A. Rather, the dissociation of PP1 from PRIP by phosphorylation accompanied the strengthened binding of PP2A in in vitro experiments. This regulation of binding of PP1 and PP2A to PRIP by PKA-dependent phosphorylation was also observed in living cells treated with forskolin or isoproterenol. These results suggested that PRIP directly interacts with the catalytic subunits of two distinct phosphatases in a mutually exclusive manner and the interactions are regulated by phosphorylation, thus functioning as a scaffold to regulate the activities and subcellular localizations of both PP1 and PP2A in phospho-dependent cellular signaling. [ABSTRACT FROM AUTHOR]

In the labial salivary glands (LSGs) of 16 primary and 18 secondary Sjögren's syndrome (SS) patients, infiltrating lymphocytes were histologically and immunohistochemically examined; also, the serum levels of rheumatoid factor, antinuclear antibodies, anti-DNA antibodies, anti-SS-A and anti-SS-B antibodies, and immunoglobulins (including IgG, IgM and IgA) were all assayed. An immunohistochemical analysis of the lymphocyte subsets in LSGs revealed that severe lymphocytic infiltration was frequently accompanied by marked B cell accumulation both in primary and secondary SS patients. Furthermore, local B cell accumulation was also closely associated with elevated levels of anti-SS-A and anti-SS-B antibodies and IgG, and this association was statistically significant in the group with primary SS but not in the group with secondary SS. Thus, local lymphocytic infiltration, especially B cell accumulation, in the salivary glands is suggested to be involved in serological abnormalities in primary SS, while complicated autoimmune diseases other than SS may also be involved in serological abnormalities in secondary SS. [ABSTRACT FROM AUTHOR]