A vascular endothelial growth factor mimetic accelerates gastric ulcer healing in an iNOS-dependent manner

Angiogenesis is crucial to all types of wound healing, including gastric ulcer healing. The most potent promoter of angiogenesis is vascular endothelial growth factor (VEGF). We hypothesized that a 15-amino acid peptide designed to mimic the angiogenic action of VEGF would accelerate gastric ulcer healing. Gastric ulcers were induced in mice by serosal application of acetic acid. Treatment with the VEGF mimetic accelerated gastric ulcer healing when administered orally or intraperitoneally, at a dose of 50 ng/kg or greater. Such healing was not observed when the reverse sequence pentadecapeptide or the full-length VEGF protein was administered. Contrary to our hypothesis, the VEGF mimetic did not significantly increase angiogenesis in the ulcerated stomach. The enhancement of ulcer healing by the VEGF mimetic occurred independently of cyclooxygenase-2 (COX-2) activity but was blocked by inhibitors of inducible nitric oxide synthase (iNOS). These results demonstrate that a VEGF mimetic is a potent stimulus for gastric ulcer healing, even when given orally. The effects of the mimetic were independent of stimulatory effects on angiogenesis and COX-2 activity but were dependent on iNOS-derived NO production.     

Cystatin B and its EPM1 mutants are polymeric and aggregate prone in vivo

Progressive myoclonus epilepsy type 1 (EPM1) is a neurodegenerative disease correlating with mutations of the cystatin B gene. Cystatin B is described as a monomeric protein with antiprotease function. This work shows that, in vivo, cystatin B has a polymeric structure, highly resistant to SDS, urea, boiling and sensitive to reducing agents and alkaline pH. Hydrogen peroxide increases the polymeric structure of the protein. Mass spectrometry analysis shows that the only component of the polymers is cystatin B. EPM1 mutants of cystatin B transfected in cultured cells are also polymeric. The banding pattern generated by a cysteine-minus mutant is different from that of the wild-type protein as it contains only monomers, dimers and some very high MW bands while misses components of MW intermediate between 25 and 250 kDa. Overexpression of wild-type or EPM1 mutants of cystatin B in neuroblastoma cells generates cytoplasmic aggregates. The cysteine-minus mutant is less prone to the formation of inclusion bodies. We conclude that cystatin B in vivo has a polymeric structure sensitive to the redox environment and that overexpression of the protein generates aggregates. This work describes a protein with a physiological role characterized by highly stable polymers prone to aggregate formation in vivo.     

Zooplankton in the Ligurian Sea: Part II. Exploration of their physical and biological forcing functions during summer 2000

A survey of the biological and physical oceanography of theLigurian Sea was conducted in the late summer of 2000. Forty-onestations were sampled for nutrients, oxygen, fluorescence andhydrographic information. Acoustic backscatter measurementswere used to estimate abundance of small (<5 mm) zooplanktonbiovolume versus depth and the distribution of northern krill,Meganyctiphanes norvegica. Net-tow and underwater video datawere collected to identify the zooplankton present. These datawere used to analyze the Ligurian Sea ecosystem for physicaland biological linkages that control zooplankton abundance anddistribution. Results are compared with those from a similarstudy conducted in 1999. Hydrographic sampling showed a domeof dense water in the southwestern middle of the basin. Thehighest chlorophyll a (Chl a) concentrations were measured inthis area, while small zooplankton biovolume was evenly distributedthroughout the survey. Integrated values of Chl a and smallzooplankton biovolume in 2000 were greater than in 1999. Meganyctiphanesnorvegica, siphonophores and salps were the dominant componentsof the macrozooplankton population in the upper 200 m. In thesampled depth strata, siphonophore abundance did not changeduring the day, while M. norvegica were only caught at night.Acoustic backscatter data show that higher densities of M. norvegicaoccurred in deeper water and in the western and southwesternareas of the Ligurian Sea.     

Selective enzymatic hydrolysis of aromatic diesters using esterase from Brevibacterium imperiale B222

Summary A practical procedure has been developed for the chemoselective microbial hydrolysis of aromatic dicarboxylic esters to give the corresponding monoesters, using cellular lysate and whole cell of Brevibacterium imperiale B222. The produced monoesters can be transformed into hydroxyacids, useful intermediates in the synthesis of polyesters.     

Oxylipins from both pathogen and host antagonize jasmonic acid‐mediated defence via the 9‐lipoxygenase pathway in Fusarium verticillioides infection of maize

Oxylipins are a newly emerging group of signals that serve defence roles or promote virulence. To identify specific host and fungal genes and oxylipins governing the interactions between maize and Fusarium verticillioides, maize wild‐type and lipoxygenase3 (lox3) mutant were inoculated with either F. verticillioides wild‐type or linoleate‐diol‐synthase 1‐deleted mutant (ΔFvlds1D). The results showed that lox3 mutants were more resistant to F. verticillioides. The reduced colonization on lox3 was associated with reduced fumonisin production and with a stronger and earlier induction of ZmLOX4, ZmLOX5 and ZmLOX12. In addition to the reported defence function of ZmLOX12, we showed that lox4 and lox5 mutants were more susceptible to F. verticillioides and possessed decreased jasmonate levels during infection, suggesting that these genes are essential for jasmonic acid (JA)‐mediated defence. Oxylipin profiling revealed a dramatic reduction in fungal linoleate diol synthase 1 (LDS1)‐derived oxylipins, especially 8‐HpODE (8‐hydroperoxyoctadecenoic acid), in infected lox3 kernels, indicating the importance of this molecule in virulence. Collectively, we make the following conclusions: (1) LOX3 is a major susceptibility factor induced by fungal LDS1‐derived oxylipins to suppress JA‐stimulating 9‐LOXs; (2) LOX3‐mediated signalling promotes the biosynthesis of virulence‐promoting oxylipins in the fungus; and (3) both fungal LDS1‐ and host LOX3‐produced oxylipins are essential for the normal infection and colonization processes of maize seed by F. verticillioides.     

Endothelial cells as early sensors of pulmonary interstitial edema.

We studied responses of endothelial and epithelial cells in the thin portion of the air-blood barrier to a rise in interstitial pressure caused by an increase in extravascular water (interstitial edema) obtained in anesthetized rabbits receiving saline infusion (0.5 ml.kg(-1).min(-1) for 3 h). We obtained morphometric analyses of the cells and of their microenvironment (electron microscopy); furthermore, we also studied in lung tissue extracts the biochemical alterations of proteins responsible for signal transduction (PKC, caveolin-1) and cell-cell adhesion (CD31) and of proteins involved in membrane-to-cytoskeleton linkage (alpha-tubulin and beta-tubulin). In endothelial cells, we observed a folding of the plasma membrane with an increase in cell surface area, a doubling of plasmalemma vesicular density, and an increase in cell volume. Minor morphological changes were observed in epithelial cells. Edema did not affect the total plasmalemma amount of PKC, beta-tubulin, and caveolin-1, but alpha-tubulin and CD-31 increased. In edema, the distribution of these proteins changed between the detergent-resistant fraction of the plasma membrane (DRF, lipid microdomains) and the rest of the plasma membrane [high-density fractions (HDFs)]. PKC and tubulin isoforms shifted from the DRF to HDFs in edema, whereas caveolin-1 increased in DRF at the expense of a decrease in phosphorylated caveolin-1. The changes in cellular morphology and in plasma membrane composition suggest an early endothelial response to mechanical stimuli arising at the interstitial level subsequently to a modest (approximately 5%) increase in extravascular water.