DBU assisted expeditious synthesis of glycosyl dienes via glycosylated beta-hydroxy esters

DBU catalyzed condensation of 3-O-benzyl(methyl)-5,6-dideoxy-1,2-O-isopropylidene-beta-L-threo-hept-4-enofuranuronates with different aldehydes produces the corresponding 3-O-benzyl(methyl)-6-carbethoxy-5,6-dideoxy-1,2-O-isopropylidene-7-phenyl-beta-L-threo-hept-4-enofuranoses. The latter on treatment with methanesulfonyl chloride followed by DBU catalyzed E2 reaction of the methanesulfonyloxy intermediates gave the respective 3-O-benzyl(methyl)-6-carbethoxy-5,6,7-trideoxy-1,2-O-isopropylidene-7-phenyl-beta-L-threo-hept-4,6-dienofuranose in moderate to good yields.     

Size, orientation and organization of oligomers that nucleate amyloid fibrils: Clues from MD simulations of pre-formed aggregates

All-atom MD simulations of pre-formed aggregates of GNNQQNY with variable size (5 to 16 peptides), orientation (parallel or anti-parallel), organization (single or double sheet, with or without twist), charge status of termini and temperature (300 and 330K) have been performed for 50ns each (68 simulations; total time=3.4μs). Double-layer systems are stable irrespective of whether the peptides within the sheet are oriented parallel or anti-parallel. The lifetime of single sheet systems is determined by the protonation status, nature of association of peptides and the size of the aggregates. For example, single sheet 8-mers are stable with parallel arrangement and neutral termini, or with anti-parallel arrangement and charged termini. This suggests that the residues flanking the amyloidogenic sequence also play an important role in determining the organization of peptides in an aggregate. Twist of the cross-beta sheets is found to be intrinsic to the aggregates. Main chain H-bonds are key determinants of stability and loss of these H-bonds is followed by disorder and/or dissociation of the peptide despite the presence of side chain hydrogen bonds. Aggregates are inherently asymmetric along the fiber axis and dissociation from the C-edge is observed more often. An aggregate can disintegrate into smaller-sized oligomers or the edge peptides can dissociate sequentially. A variety of dissociation and disintegration events are observed pointing to the existence of multiple pathways for association during nucleation. It appears that a heterogeneous mixture of oligomers of different sizes exist prior to the formation of the critical nucleus.     

Transforming growth factor-β protein inversely regulates in vivo differentiation of interleukin-17 (IL-17)-producing CD4+ and CD8+ T cells

TGF-β is a pleiotropic cytokine that predominantly exerts inhibitory functions in the immune system. Unexpectedly, the in vitro differentiation of both Th17 and Tc17 cells requires TGF-β. However, animals that are impaired in TGF-β signaling (TGF-βRIIDN mice) display multiorgan autoimmune disorders. Here we show that CD4(+) T cells from TGF-βRIIDN mice are resistant to Th17 cell differentiation and, paradoxically, that CD8(+) T cells from these animals spontaneously acquire an IL-17-producing phenotype. Neutralization of IL-17 or depletion of CD8(+) T cells dramatically inhibited inflammation in TGF-βRIIDN mice. Therefore, the absence of TGF-β triggers spontaneous differentiation of IL-17-producing CD8(+) T cells, suggesting that the in vivo and in vitro conditions that promote the differentiation of IL-17-producing CD8(+) T cells are distinct.     

Synthesis of 3-(1-alkyl/aminoalkyl-3-vinyl-piperidin-4-yl)-1-(quinolin-4-yl)-propan-1-ones and their 2-methylene derivatives as potential spermicidal and microbicidal agents

A series of twenty two derivatives of 3-(1-alkyl/aminoalkyl-3-vinyl-piperidin-4-yl)-1-(quinolin-4-yl)-propan-1-one and their 2-methylene derivatives were synthesized from naturally abundant cinchonine (I). Tartarate salts of these compounds were prepared and evaluated for spermicidal activity. The most active compounds (24, 27, 34, 36, and 38) showing potent spermicidal activity were further evaluated against different strains of Trichomonas vaginalis, for antimicrobial activity, in HeLa cell lines for cytotoxicity and against Lactobacillus jensenii for eco-safety. The tartarate of 3-(1-pentyl-3-vinyl-piperidin-4-yl)-1-(quinolin-4-yl)-propan-1-one (27) was found to be more active than N-9 in spermicidal activity.     

Global Warming Impact of E85 Fuel Derived from Forest Biomass: A Case Study from Southern USA

This study estimates global warming impact (GWI) of E85 fuel needed to run a small passenger car for its average lifetime, i.e., 241,402 km (150,000 miles). The ethanol needed for the production of E85 fuel was derived from an intensively managed slash pine (Pinus elliottii) plantation in the southern USA. We assumed that only pulpwood and harvesting residues obtained at the time of harvesting were used for ethanol production. A suitable system boundary was defined and a detailed life-cycle assessment was undertaken to determine GWI of all the steps present within the system boundary. Results indicate that the overall GWI of the E85 fuel was about 76% less than an equivalent amount of gasoline needed to run a small passenger car for its average lifetime. Within the system boundary, the GWI of the ethanol production stage was highest followed by the stage of E85 fuel consumption in a small passenger car. A need exists to evaluate impacts of utilizing forest biomass for E85 fuel production on forest ecology and traditional forest biomass-based industries.     

Safety evaluation of genetically modified mustard (V4) seeds in terms of allergenicity: Comparison with native crop

Genetically modified (GM) mustard line (V4) with increased carotenoid content was compared with native mustard to find the difference in allergenic potential, if any. Simulated gastric fluid (SGF) digestibility of crude protein extract from GM as well as its native counterpart mustard crop was envisaged to understand the intended or unintended changes in GM crop along with IgE immunoblotting. BALB/c mice were used as model for allergenicity studies for monitoring total and specific IgE, specific IgG1, histamine level, histopathology, and systemic anaphylaxis score. Allergenicity of mustard was checked in humans by clinical history, skin prick test and IgE levels. Similar results were evident by significant increase in total IgE, specific IgE, IgG1, histamine levels, in GM and native mustard in comparison to control group. Prominent anaphylactic symptoms (score 2: 60%; score 3: 20%; score 4: 20% in native mustard and score 2: 40%; score 3: 40%; score 4: 20% in GM mustard) and eruptive histopathological changes were observed in both GM and native mustard when compared with controls. One protein of approximately 16 kDa was found stable up to 1 h in both GM as well as non GM mustard. IgE immunoblotting detected three protein components of approximately 29, 24 and 16 kDa in both GM and non GM varieties. Collectively, our data demonstrate substantially equivalent allergic responses against GM as well as its native counterpart. Therefore, the GM mustard may be as safe as its native counterpart with reference to allergenic responses.     

Concurrent Conditions in Patients with Chronic Constipation: A Population–Based Study

Background

Chronic constipation (CC) is a common condition but its concurrent conditions are not well characterized. We measured the prevalence and risk of developing 15 pre–specified concurrent conditions in patients with CC.

Methods

Retrospective cohort study using the Medicaid database of California, utilizing ICD-9 codes for detection of cases (CC), controls (patients with GERD) and concurrent conditions. Study period was 01/01/1995 to 06/30/2005. Index date was the date 3 months before the first physician visit for CC. Pre-index time (12 months) was compared to post-index time (12 months) to assess the association of every concurrent condition within each cohort. To account for ascertainment bias, an adjusted odds ratio was calculated by comparing the odds ratio for every concurrent condition in the CC cohort to that in the GERD cohort.

Results

147,595 patients with CC (mean age 54.2 years; 69.7% women; 36.2% white) and 142,086 patients with GERD (mean age 56.3 years; 65.3% women; 41.6% white) were evaluated. The most prevalent concurrent conditions with CC were hemorrhoids (7.6%), diverticular disease (5.9%), ano–rectal hemorrhage (4.7%), irritable bowel syndrome (3.5%) and fecal impaction (2%). When adjusted for ascertainment bias, the most notable associations with CC were Hirschsprung''s disease, fecal impaction and ano-rectal conditions such as fissure, fistula, hemorrhage and ulcers.

Conclusion

Chronic constipation is associated with several concurrent conditions of variable risk and prevalence. To reduce the overall burden of CC, these concurrent conditions need to be addressed.     

A novel membrane-dependent on/off switch mechanism of talin FERM domain at sites of cell adhesion

The activation of heterodimeric (α/β) integrin transmembrane receptors by cytosolic protein talin is crucial for regulating diverse cell-adhesion-dependent processes, including blood coagulation, tissue remodeling, and cancer metastasis. This process is triggered by the coincident binding of N-terminal FERM (four-point-one-protein/ezrin/radixin/moesin) domain of talin (talin-FERM) to the inner membrane surface and integrin β cytoplasmic tail, but how these binding events are spatiotemporally regulated remains obscure. Here we report the crystal structure of a dormant talin, revealing how a C-terminal talin rod segment (talin-RS) self-masks a key integrin-binding site on talin-FERM via a large interface. Unexpectedly, the structure also reveals a distinct negatively charged surface on talin-RS that electrostatically hinders the talin-FERM binding to the membrane. Such a dual inhibitory topology for talin is consistent with the biochemical and functional data, but differs significantly from a previous model. We show that upon enrichment with phosphotidylinositol-4,5-bisphosphate (PIP2) – a known talin activator, membrane strongly attracts a positively charged surface on talin-FERM and simultaneously repels the negatively charged surface on talin-RS. Such an electrostatic “pull-push” process promotes the relief of the dual inhibition of talin-FERM, which differs from the classic “steric clash” model for conventional PIP2-induced FERM domain activation. These data therefore unravel a new type of membrane-dependent FERM domain regulation and illustrate how it mediates the talin on/off switches to regulate integrin transmembrane signaling and cell adhesion.