Major intrinsic polypeptide (MIP26K) of the lens membrane: covalent change in an internal sequence during human senile cataractogenesis

Polyclonal antisera to three synthetic peptides of bovine MIP26K have been used in combination with Western blot analysis to probe for changes of the MIP26K molecule during human senile cataractogenesis. Anti-MIP26K229-237 binds well to the 26K component from cataractous lens membranes, but binds poorly to the same component from normal lens. In contrast, antisera to two other sequences of MIP26K (anti-MIP26K252-259 and anti-MIP26K256-263) bind approximately equally well to the 26K component from either cataractous or normal lens. Together, these results demonstrate that during cataract development there is a selective covalent change in a region of the MIP26K molecule that may have profound effects upon the ability of this molecule to facilitate intercellular communication between lens fiber cells.     

Isolation and Chemical Structure of New Oxidation Product of 5-Ketogluconic Acid,and a Hypothetical Pathway from Glucose to Tartaric Acid through this New Compound

In the course of study on the mechanism of the tartaric acid formation from 5-ketogluconic acid, a new intermediary substance with mauve color to Abdel-Akhel and Smith’s reagent was isolated from intact cell culture liquid. The chemical structure of this substance was determined as 1,2-dihydroxyethyl hydrogen L(+) tartrate from the results of hydrolysis experiments and from the identifications of the constituents of the molecule, and named “pretaric acid.” Tartaric acid was evidently produced from pretaric acid by intact cell culture. Clearly, then, pretaric acid appears to be an intermediate in the formation of tartaric acid from 5-ketogluconic acid. The authors assumed that in the formation of pretaric acid from 5-ketogluconic acid, a Baeyer-Villiger type oxidation occurred.     

Bacterial cometabolic degradation of chlorinated paraffins

Summary Cometabolic dechlorination of chlorinated paraffins was demonstrated in the presence of n-hexadecane by bacterial strains (HK-3, HK-6, HK-8, and HK-10) isolated from soil samples.Eleven per cent of chlorine of chlorinated paraffin-150 (CP-150) was released by strain HK-3. The mixed culture of strain HK-3, catalyzing the dechlorination of terminal chlorine of chloroalkane, and strain H15-4, capable of releasing the chlorine from 2-chlorinated fatty acids, dechlorinated CP-150 up to 13%. The mixed culture of the four strains (HK-3, HK-6, HK-8, and HK-10) performed the dechlorination of CP-150 by cometabolism in a jar fermentor pH at 7.0. The amount of chloride released from the chlorinated paraffins tested was in the range of 15–57%.The activated sludge acclimatized to n-hexadecane for 60 days showed a little dechlorination activity to CP-150.     

Density dependent growth of corneal endothelial cells cultured in vitro

Using the cornea of macaque monkey, we demonstrated the relationship between cell density and growth of endothelial cells in vitro. Corneal endothelial cells in a cell sheet grow most actively in regions with cell density of 1000 to 1800 cells/mm2, in explant cultures and cell sheets and in concentrated inocula dissociated cells. Cell morphology was well sustained in these cultures. Cells cultured at a higher cell density retained their potential to proliferate actively, showing clear contrast to cells cultured at a density lower than 200 cells/mm2. When dissociated cells were cultured at a low density and maintained for more than 4 weeks, they gradually lost their growth potential, altered into polymorphonuclear giant cells and eventually dedifferentiated. In addition, cells with no contact with each other did not express growth potential. Density dependent growth was confirmed by measuring the mitotic index against the cell density per square mm from the center to the peripheral regions in cultured explants. It is concluded that the growth pattern of corneal endothelial cells is closely related to cell density, and that growth of these cells might be regulated through intercellular communications.     

Purification and properties of haloalkane dehalogenase from Corynebacterium sp. strain m15-3

A haloalkane dehalogenase was purified to electrophoretic homogeneity from cell extracts of a 1-chlorobutane-utilizing strain, m15-3, which was identified as a Corynebacterium sp. The enzyme hydrolyzed C2 to C12 mono- and dihalogenated alkanes, some haloalcohols, and haloacids. The Km value of the enzyme for 1-chlorobutane was 0.18 mM. Its molecular weight was estimated to be 36,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and 33,000 by gel filtration. The isoelectric point was pH 4.5. The optimum pH for enzyme activity was found to be 9.4, and the optimum temperature was 30 to 35 degrees C. The enzyme was stable for 1 h at temperatures ranging from 4 to 30 degrees C but was progressively less stable at 40 and 50 degrees C.     

Stellate cells storing retinol in the liver of adult lamprey,Lampetra japonica

Summary Distribution, localization and fine structure of the stellate cells in the liver of lamprey, Lampetra japonica, were studied during the spawning migration by use of Kupffer's gold-chloride method, fluorescence microscopy for vitamin A (retinol) and electron microscopy. The stellate cells in the lamprey liver differ in some of their properties from those in mammalian livers. Stellate cells which store abundant retinol in lipid droplets, occur not only in the hepatic parenchyma, but also in the dense perivascular and capsular connective tissue of the liver and in the interstitium of pancreatic tissue. In the hepatic parenchyma these cells are located perisinusoidally or along thick bundles of collagen fibrils. The stellate cells display a number of large retinol-containing lipid droplets, granular endoplasmic reticulum, tubular structures, dense bodies, Golgi complex, microtubules, and microfilaments. In the space of Disse, the stellate cells and extracellular fibrilar components such as collagen fibrils and microfibrils (11–12 nm in diameter) are intervened between the two layers of basal laminae. Differentiation and possible functions of the stellate cells in the lamprey liver are discussed.     

Splenic outer periarterial lymphoid sheath (PALS): An immunoproliferative microenvironment constituted by antigen-laden marginal metallophils and ED2-positive macrophages in the rat

Summary In an attempt to reveal the role of antigen-laden marginal metallophil (MM) and other macrophages in the intrasplenic immune response of a specific B-cell lineage to a thymus-independent type-2 antigen (Ficoll conjugated with fluorescein isothiocyanate), simultaneous immuno-histological observations of the involved cells were performed in the rat. By newly established methods of double or triple immunostainings, time-kinetics of the following parameters were studied and compared: (1) the antigen, (2) the specific antibody-forming cells (AFC) directed to the fluorescein-isothiocyanate determinant, (3) proliferating cells labeled with 5-bromo-2-deoxyuridine (BrdU), and (4) macrophage subpopulations recognized by monoclonal antibodies (ED2 and ED3). The antigen localized stably not only in the marginal-zone macrophages but also in the MM except around the follicular area. The increase of BrdU-positive cells was observed from day 2 up to day 4 after antigen injection mostly in the periphery of the periarterial lymphoid sheath (outer PALS), which indicated antigen-induced proliferation. As a novel finding, the majority of AFC, both BrdU-positive and -negative, were either closely associated with the antigen-laden MM, or forming cell clusters with ED2-positive macrophages in the outer PALS. In contrast, there were very few AFC in juxtaposition to antigen-free MM in the follicular area or the antigen-laden marginal zone macrophages. The results led to the proposal of a hypothesis that the antigen-laden MM together with ED2-positive macrophages constitute an immunoproliferative microenvironment for the plasmacellular reaction by accumulating the antigen-specific B-cell lineage and promoting these cells to differentiate into the AFC and to proliferate in the outer PALS.Abbreviations AFC specific antibody-forming cells - BrdU 5-bromo-2-deoxyuridine - Fic-F FITC-conjugated Ficoll - FITC fluorescein isothiocyanate - HRP horseradish peroxidase - MM marginal metallophils - MZ marginal zone - PALS periarterial lymphoid sheath - PBS phosphate-buffered saline - TI2 thymus-independent type-2     

Three-dimensional structure of endothelial cells in hepatic sinusoids of the rat as revealed by the Golgi method

Summary The three-dimensional structure of endothelial cells in the hepatic sinusoids of the rat was studied by application of light- and electron microscopy on Golgi-impregnated specimens. A number of endothelial cells could thus be individually delineated throughout the hepatic lobules. The cytoplasm, showing heavy silver deposits, consists of two distinct areas, a thick and thin portion. The thick portion, issuing from the region of the perikaryon, branches and tapers toward the cell periphery. The thin portion, occupying the remainder of the cytoplasm, consists largely of highly fenestrated sieve plates. Some intralobular variation can be noted; the thick portion of the endothelial cells is well developed in the periportal zone, while the cells in the centrilobular zone are relatively rich in thin portions. In addition, the area of distribution of an individual endothelial cell is larger in the centrilobular sinusoids than in the periportal zone. Some endothelial cells also possess unique cytoplasmic processes projecting into the intercellular space between hepatocytes and connecting the sinusoidal walls of neighboring sinusoids. These processes may anchor the endothelial cells to the hepatic plates.