Secreted Protein Acidic and Rich in Cysteine as A Regeneration Factor: Beyond the Tissue Repair

Diverse pathologies (inflammation, tissues injuries, cancer, etc.) and physiological conditions (obesity, physical activity, etc.) induce the expression/secretion of the matricellular protein, secrete protein acidic and rich in cysteine (SPARC). SPARC contributes to the creation of an environment that is suitable for tissue regeneration through a variety of roles, including metabolic homeostasis, inflammation reduction, extracellular matrix remodeling and collagen maturation. Such a homeostatic environment optimizes tissue regeneration and improves tissues’ repair ability. These properties that SPARC has within the regeneration contexts could have a variety of applications, such as in obesity, cancer, sarcopenia, diabetes and bioengineering.

From bugs to beta cells

Certain microbes in the intestine secrete protein that stimulates the proliferation of beta cells in the pancreas during development.

Research Progress on Adhesion Mechanism of Marine Organism

Marine adhesion organism includes biological mucosa such as marine bacteria, diatom, etc. and large adhesion organism such as mussel, barnacle, etc. Researches and analysis on adhesion mechanism of adhesion organism show that adhesion marine bacteria in biological mucosa will secrete protein-containing Polysaccharide polymer (PAVE) which can adhere to all kinds of surfaces. The reason is that in these secretions there is 3, 4-dihydroxyphenylalanine (DOPA) which is very viscous. Analysis on mussel, a large adhesion organism, shows that it is of super viscosity, which may result from its special molecular structure and the interaction way with substrates, and interstrand crosslink mediated by DOPA. DOPA plays an important role in this process. For marine bacteria and mussel, their viscosity is correlated with the generation and cross-linking of DOPA. On one hand, DOPA can enhance the viscosity of adhesion organism; on the other hand, it can improve the internal cohesion through cross-linking.

Impassable YscP Substrates and Their Impact on the Yersinia enterocolitica Type III Secretion Pathway

ABSTRACT Yersinia type III machines secrete protein substrates across the bacterial envelope and, following assembly of their secretion needles, transport effector Yops into host cells. According to their destination during type III secretion, early, middle, and late secretion substrates can be distinguished; however, the signals and mechanisms whereby these proteins are recognized and transported by the secretion machine are not understood. Here, we examine several hybrids between secretion substrates and the impassable reporter protein glutathione S-transferase (GST). YscP-GST and YopR-GST blocked type III secretion; however, YscF-, YopD-, YopN-, and LcrV-GST did not. Unlike YopR-GST, which can block type III machines only during their assembly, expression of YscP-GST led to an immediate and complete block of all secretion. The secretion signal of YscP was mapped to its first 10 codons or amino acids; however, YscPΔ2-15-GST, lacking this secretion signal, imposed a partial blockade. YscP-GST copurified with the type III ATPase complex (YscN, YscL, and YscQ) and with YscO, suggesting that the association of specific machine components with the impassable substrate may cause the block in type III secretion.

Persistence of a perinatal cellular phenotype in submandibular glands of adult rat.

In the perinatal submandibular gland (SMG) of the rat, Type I cells secrete protein C (89 KD) and Type III cells secrete B1-immunoreactive proteins (20-30 KD); both cell types secrete protein D (175 KD). After the disappearance of both perinatal cell types from the maturing acini, only cells of the intercalated ducts (ID) show strong reactivity for the perinatal antigens. In adult ID, light and electron microscopic immunocytochemical analysis showed that most cells had either C or B1 reactivity, a few had either C and D or B1 and D reactivities, and some cells were unreactive for all of the perinatal proteins. Occasional clusters of "adult" acini, however, were strongly positive for B1 and for D, and these clusters were negative for a typical adult acinar marker, the glutamine/glutamic acid-rich proteins (GRP). Also seen in some preparations were a few anomalous acini with the histological appearance of sublingual (SLG) acini. These were negative for the perinatal and adult submandibular gland marker proteins but reactive with an antibody against SLG mucin. We suggest that the B1-positive acini in the adult SMG consist of newly differentiated replacement cells that have arisen from the ID, and that the anomalous mucous acini are, phenotypically, SLG acini that have differentiated within the SMG parenchyma.

The Histochemistry of the labial Salivary Glands of the Spiny-Tailed Lizard Uromastyx microlepis (Blandford)*

The labial salivary glands of the spiny-tailed lizard, Uromastyx microlepis (Blandford) were used in morphometric, histological and histochemical investigations. Both supra and infralabial glands are of the compound tubulo-acinar type and are of a mixed nature containing both mucous and mucoserous cells. The mucous cells secrete and elaborate neutral mucosubstances, sialomucins and hyaluronidase resistant sulfomucins, whereas the mucoserous cells secrete protein radicals as well. The histoenzymological tests used have detected alkaline phosphatase, succinic dehydrogenase and carbonic anhydrase in these glands.

MEMBRANE-BOUND RIBOSOMES IN KIDNEY

Membrane-bound ribosomes are thought to secrete protein for export and free ribosomes to secrete protein for intracellular use. The proportion of the total ribosomes that is bound to membranes in normal mouse kidneys has been estimated by three different methods, and the results have been compared with those obtained by a fourth method used by us previously. The most valid estimates appear to be those obtained (a) by comparison of radioactivity in peaks representing free and membrane-bound ribosomes on linear sucrose gradients after labeling for 24 hr with 14C-orotic acid, and (b) by measurements of optical density in free and bound ribosomes that had been separated by centrifugation on discontinuous gradients of 0.5 M/2.0 M sucrose. Analyses by these methods show that about 20–25% of the ribosomes in a postnuclear supernatant prepared from mouse kidneys, but only 10–15% of the ribosomes in a post-mitochondrial supernatant, are membrane-bound. About 75% of the bound ribosomes sediment as polysomes of many different sizes. The proportion of membrane-bound ribosomes and their aggregation into polysomes were unchanged in kidneys undergoing compensatory hypertrophy after removal of the opposite kidney. These experiments show that, unlike liver, kidney has a predominance of free ribosomes compared to bound ribosomes; those ribosomes that are membrane-bound do not become free during compensatory renal growth.