A comparative study of different glycosylation methods for the synthesis of D-mannopyranosides of Nalpha-fluorenylmethoxycarbonyl-trans-4-hydroxy-L-proline allyl ester

The synthesis of Nalpha-fluorenylmethoxycarbonyl-trans-4-hydroxy-4-O-[(2,3,4,6-tetra-O-acetyl)-alpha-d-mannopyranosyl]-l-proline allyl ester and Nalpha-fluorenylmethoxycarbonyl-trans-4-hydroxy-4-O-[(2,3,4,6-tetra-O-benzoyl)-alpha-d-mannopyranosyl]-l-proline allyl ester is described. Glycosylation using K?nigs-Knorr conditions with a benzoyl protected glycosyl donor provided the optimum method. Removal of the allyl ester gave two mannosylated building blocks suitable for solid phase glycopeptide synthesis.     

Studies of insect peptides alloferon,Any‐GS and their analogues. Synthesis and antiherpes activity

The subject of these studies was synthesis and determination of biological properties of a series of insect peptides, such as alloferon, Any‐GS and their analogues. The synthesis of 14 peptides was performed by the solid‐phase method. Biological effect of these peptides was evaluated by the antiviral test against Human Herpes Virus type 1 (HHV‐1) in vitro using a Vero cell line. It was found that the investigated peptides inhibit the replication of HHV‐1 in Vero cells. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.     

Beta-carotene storage, conversion to retinoic acid, and induction of the lipocyte phenotype in hepatic stellate cells

Hepatic stellate cells (HSCs) are the major site of retinol (ROH) metabolism and storage. GRX is a permanent murine myofibroblastic cell line, derived from HSCs, which can be induced to display the fat-storing phenotype by treatment with retinoids. Little is known about hepatic or serum homeostasis of beta-carotene and retinoic acid (RA), although the direct biogenesis of RA from beta-carotene has been described in enterocytes. The aim of this study was to identify the uptake, metabolism, storage, and release of beta-carotene in HSCs. GRX cells were plated in 25 cm(2) tissue culture flasks, treated during 10 days with 3 micromol/L beta-carotene and subsequently transferred into the standard culture medium. beta-Carotene induced a full cell conversion into the fat-storing phenotype after 10 days. The total cell extracts, cell fractions, and culture medium were analyzed by reverse phase high-performance liquid chromatography for beta-carotene and retinoids. Cells accumulated 27.48 +/- 6.5 pmol/L beta-carotene/10(6) cells, but could not convert it to ROH nor produced retinyl esters (RE). beta-Carotene was directly converted to RA, which was found in total cell extracts and in the nuclear fraction (10.15 +/- 1.23 pmol/L/10(6) cells), promoting the phenotype conversion. After 24-h chase, cells contained 20.15 +/- 1.12 pmol/L beta-carotene/10(6) cells and steadily released beta-carotene into the medium (6.69 +/- 1.75 pmol/ml). We conclude that HSC are the site of the liver beta-carotene storage and release, which can be used for RA production as well as for maintenance of the homeostasis of circulating carotenoids in periods of low dietary uptake.     

The MMP/TIMP system in the nervous system

The matrix metalloproteinases (MMP) belong to a growing family of secreted or membrane-bound (MT-MMP) enzymes that cleave protein components of the extracellular matrix and bioactive factors involved in intercellular signaling. MMP activity is counterbalanced by their four physiological inhibitors, the tissue inhibitors of MMP (TIMPs). Together, MMP and TIMP control cell-cell and cell-matrix interactions associated with physiological processes. However, the breakdown of the protease-inhibitor balance may lead to the loss of tissue homeostasis and the development of degenerative and tumorigenic processes in various tissues. The emerging idea is that the MMP/TIMP system also plays a major role in the pathology and physiology of the nervous system and that mastering MMP activity will set the basis for new and more efficient therapeutic strategies against nervous system disorders.     

Abrogation of hepatocyte apoptosis and early appearance of liver dysplasia in ethanol-fed p53-deficient mice

Ethanol consumption represents a major risk factor for cancer development, and a significant fraction of hepatocarcinomas arises in alcoholic liver cirrhosis. Increasing evidence indicates that ethanol acts as a tumor promoter on genetically initiated cells, by increasing the intracellular concentration of reactive oxygen species and promoting tissue necrosis/regeneration and cell proliferation. The tumor suppressor p53 restrains the expansion of carcinogen-initiated cells by inducing cell cycle arrest and apoptosis; accordingly, p53-deficient mice develop spontaneous and chemically induced neoplasms at a much higher frequency than normal mice. In normal mice exposed to a subacute (3 weeks) ethanol intoxication, a significant increase in the number of apoptotic hepatocytes was observed in concomitance with the up-regulation of the mitochondrial superoxide scavenger MnSOD, a reliable indicator of oxidative stress. Cell death occurred in the absence of liver inflammation and necrosis. Ethanol-induced hepatocyte apoptosis was completely abrogated in the p53 null background, suggesting that the tumor suppressor is necessary for hepatocyte death by ethanol. Accordingly, p53 -/- MEF were, unlike wild type cells, completely insensitive up to 0.5M ethanol in the culture medium. Strikingly, marked and widespread signs of dysplasia, with nuclear pleomorphisms and initial loss of normal architecture, heralding malignant transformation, were scored in all the mutant mice exposed to ethanol, but not in the control-fed littermates nor in ethanol-fed normal mice. These observations suggest that p53-dependent apoptosis restrains the tumorigenic effect of ethanol on liver cells, in agreement with the frequent loss of p53 function in HCC, and reveal an unexpected carcinogenic potential of alcohol which appears to be independent from the induction of cirrhosis and hepatocyte regeneration.     

Effects of forest fragmentation on small mammals in an Atlantic Forest landscape

Recent studies on the effects of tropical forest fragmentation indicate that fragmented landscapes are complex and heterogeneous systems influenced by factors other than the size or degree of isolation of forest remnants: of particular importance are the quality of the matrix and the edge-induced habitat changes. In order to investigate the influence of these factors, small mammals were surveyed in 36 sites in the landscape of Una, a region that encompasses some of the last and largest Atlantic Forest remnants in northeastern Brazil. Six sites were distributed on each of six landscape components – the interiors and edges of small remnants, the interiors and edges of large remnants, and the most common forested habitats found in the matrix. The survey comprised 46,656 trap-nights and yielded 1725 individuals of 20 species of rodents and marsupials. Results revealed: an increase in beta-diversity caused by fragmentation; the contrasting effects of the altered forested habitats of the matrix, which harbor both forest and disturbance-adapted species; a greater importance of edge effect than of patch size to the observed changes in small mammal community in remnants; an association among terrestrial forest species and among arboreal forest species in terms of the distribution and abundance in the Una mosaic; and a distinctive vulnerability of these two groups of species to fragmentation. Results emphasize the biological importance and conservation value of both fragmented landscapes and small remnants in the Atlantic Forest, as well as the importance of management techniques to control and attenuate edge effects.     

Deciphering the molecular machinery of stem cells: a look at the neoblast gene expression profile

Background  

Mammalian stem cells are difficult to access experimentally; model systems that can regenerate offer an alternative way to characterize stem cell related genes. Planarian regeneration depends on adult pluripotent stem cells - the neoblasts. These cells can be selectively destroyed using X-rays, enabling comparison of organisms lacking stem cells with wild-type worms.     

Increased hip internal abduction moment and reduced speed are the gait strategies used by women with knee osteoarthritis

The purpose of this study was to identify the gait strategies in women with mild and moderate knee osteoarthritis (OA). Forty women diagnosed with OA of the knee and 40 healthy women participated in the study. Toe-out progression angle, trunk lateral lean, hip internal abduction moment and gait speed were measured using Qualisys ProReflex System and two force plates. Principal component analysis was applied to extract features from the gait waveforms data that characterized the waveforms main modes of temporal variation. Discriminant analysis with a stepwise model was conducted to determine which strategies could best discriminate groups. According to the discriminant model, the PC2 of the internal abduction moment of the hip and the gait speed were the most discriminatory variables between the groups. The OA group showed decreased gait speed, decreased hip internal abduction moment during the loading response phase, and increased hip internal abduction moment during the mid and terminal stance phases. Interventions that may increase hip internal abduction moment, such as the strengthening of the hip abductors muscles, may benefit women with knee OA. Training slower than normal gait speeds must be considered in light of potential adverse implications on overall physical function, daily tasks, and safety.     

Isolation of new toluene-tolerant marine strains of bacteria and characterization of their solvent-tolerance properties

Aims:  To isolate and characterize new marine bacteria capable of tolerating high concentrations of organic solvents, and to understand the toxic effects of these chemicals on marine bacteria. Methods and Results:  Five marine bacteria able to tolerate 0·1% (v/v) toluene were isolated and characterized on the basis of their growth and survival rates in the presence of different organic solvents. The toluene-tolerant marine bacteria identified in this study could not grow in the presence of 0·1% (v/v) of several organic solvents with a log P_ow higher than that of the toluene (which in theory should be less toxic than toluene). The mechanisms underlying solvent tolerance were explored. Conclusions:  Isolates of four different genera were identified as toluene-tolerant. Toxicity of a second phase of an organic solvent toward these isolates could not be predicted on the basis of the solvents’ log P_ow. Significance and Impact of the Study:  To improve the biodegradation rate of some water-insoluble compounds, double-phase bioreactors can be used. This type of bioreactor will require strains able to grow in a salt-containing environment and able to tolerate a second phase of an organic solvent.     

Polymicrobial Infection with Major Periodontal Pathogens Induced Periodontal Disease and Aortic Atherosclerosis in Hyperlipidemic ApoEnull Mice

Periodontal disease (PD) and atherosclerosis are both polymicrobial and multifactorial and although observational studies supported the association, the causative relationship between these two diseases is not yet established. Polymicrobial infection-induced periodontal disease is postulated to accelerate atherosclerotic plaque growth by enhancing atherosclerotic risk factors of orally infected Apolipoprotein E deficient (ApoE^null) mice. At 16 weeks of infection, samples of blood, mandible, maxilla, aorta, heart, spleen, and liver were collected, analyzed for bacterial genomic DNA, immune response, inflammation, alveolar bone loss, serum inflammatory marker, atherosclerosis risk factors, and aortic atherosclerosis. PCR analysis of polymicrobial-infected (Porphyromonas gingivalis [P. gingivalis], Treponema denticola [T. denticola], and Tannerella forsythia [T. forsythia]) mice resulted in detection of bacterial genomic DNA in oral plaque samples indicating colonization of the oral cavity by all three species. Fluorescent in situ hybridization detected P. gingivalis and T. denticola within gingival tissues of infected mice and morphometric analysis showed an increase in palatal alveolar bone loss (p<0.0001) and intrabony defects suggesting development of periodontal disease in this model. Polymicrobial-infected mice also showed an increase in aortic plaque area (p<0.05) with macrophage accumulation, enhanced serum amyloid A, and increased serum cholesterol and triglycerides. A systemic infection was indicated by the detection of bacterial genomic DNA in the aorta and liver of infected mice and elevated levels of bacterial specific IgG antibodies (p<0.0001). This study was a unique effort to understand the effects of a polymicrobial infection with P. gingivalis, T. denticola and T. forsythia on periodontal disease and associated atherosclerosis in ApoE^null mice.