Fibronectin fragmentation promotes alpha4beta1 integrin-mediated contraction of a fibrin-fibronectin provisional matrix

In injured tissues, the fibrin-fibronectin (FN) provisional matrix provides a framework for cell adhesion, migration, and repair. Effective repair and remodeling require a proper balance between extracellular matrix (ECM) deposition, contraction, and turnover. We utilized a three-dimensional (3D) fibrin-FN provisional matrix model to determine the contributions of the FN-binding integrin receptors alpha5beta1 and alpha4beta1 to matrix contraction. CHOalpha5 cells expressing alpha5beta1, a receptor for FN's RGD cell-binding domain, were highly contractile, and cells were well spread on a 3D fibrin-FN matrix. In contrast, CHOalpha4 cells expressing the alpha4beta1 receptor for FN's alternatively spliced V region attached less efficiently to FN and were deficient in fibrin-FN matrix contraction. Surprisingly, cell adhesion and matrix contraction by CHOalpha4 cells were dramatically enhanced, to levels equivalent to CHOalpha5 cells, when proteolyzed FN was used in place of intact FN in the fibrin-FN matrix. Similar enhancement was observed when ligand binding by alpha4beta1 integrins was activated by treatment with Mn(++), but not by stimulation of actin organization with LPA. Therefore, alpha4beta1-dependent cell responses to the provisional matrix are modulated by cleavage of matrix components.     

Feasibility of using the national hospital discharge survey to estimate the prevalence of selected birth defects

BACKGROUND: Nationally representative data on the prevalence of certain birth defects are largely unavailable. We evaluated the feasibility of using data from the National Hospital Discharge Survey (NHDS) to describe the prevalence of selected birth defects. METHODS: All live births recorded in the NHDS during 1999-2001 were included. The prevalence for selected birth defects was calculated using weighted ratio estimators. Prevalence ratios comparing the NHDS estimates to published national estimates from the National Birth Defects Prevention Network (NBDPN) were calculated. RESULTS: With the exception of common truncus, the NHDS prevalence for the selected defects was consistently lower than the NBDPN estimates. The prevalence ratios ranged from 0.38 for trisomy 18 and anopthalmia/micropthalmia to 1.16 for common truncus. The NHDS prevalence estimates for spina bifida without anencephaly (PR 0.89, 95% CI: 0.57-1.22) and gastroschisis/omphalocele (PR 0.94, 95% CF: 0.48-1.40) most closely approximated the NBDPN estimates. CONCLUSIONS: NHDS data underestimate the prevalence of most birth defects. Additional research is needed to determine whether NHDS estimates may be useful for evaluating trends in certain conditions. Surveillance systems employing active case-finding continue to provide more accurate estimates of birth defects prevalence.     

Cell surface display of Chi92 on Escherichia coli using ice nucleation protein for improved catalytic and antifungal activity

The gene encoding chitinase 92 (Chi92) from Aeromonas hydrophila JP10 has been displayed on the cell surface of Escherichia coli using the N-terminal region of ice nucleation proteins (INPN) as an anchoring motif. Immunofluorescence microscopy confirmed that Chi92 was anchored on the cell surface. Western blot analysis further identified the synthesis of INP derivatives containing the N-terminal domain INPN-Chi92 fusion protein of the expected size (112 kDa). Whole cell enzyme assay indicated that the displayed Chi92 showed enhanced catalytic activity toward colloidal chitin. In addition, the Chi92-displayed cells exhibited inhibitory effects on the mycelial growth of phytopathogenic fungi, including Fusarium decemcellulare, Sclerotium rolfsii, Rhizoctonia solani kuhn, and Fusarium oxysporum f.sp. melonis. This study suggested that the INP-based display systems can be used to express a large protein (90 kDa Chi92) on the cell surface of E. coli without growth inhibition. In addition, the display of chitinase on the cell surface may provide an attractive method for the development of biocontrol agents against phytopathogenic fungi.     

Dipeptidyl-peptidase IV inhibitory activity of peptides derived from tuna cooking juice hydrolysates

The in vitro DPP-IV inhibitory activity of isolated peptides from of tuna cooking juice hydrolyzed by Protease XXIII (PR) and orientase (OR) was determined. The results showed that the peptide fractions with the molecular weight over 1,422 Da possessed the greatest DPP-IV inhibitory activity. The amino acid sequences of the three peptides isolated from PR and OR hydrolysates were identified by MALDI-TOF/TOF MS/MS, and they were Pro-Gly-Val-Gly-Gly-Pro-Leu-Gly-Pro-Ile-Gly-Pro-Cys-Tyr-Glu (1412.7 Da), Cys-Ala-Tyr-Gln-Trp-Gln-Arg-Pro-Val-Asp-Arg-Ile-Arg (1690.8 Da) and Pro-Ala-Cys-Gly-Gly-Phe-Try-Ile-Ser-Gly-Arg-Pro-Gly (1304.6 Da), while they showed the dose-dependent inhibition effect of DPP-IV with IC(50) values of 116.1, 78.0 and 96.4 μM, respectively. In vitro simulated gastrointestinal digestion retained or even improved the DPP-IV inhibitory activities of the three peptides. The results suggest that tuna cooking juice would be a good precursor of DPP-IV inhibitor, and the DPP-IV inhibitory peptides can successfully passed through the digestive tract.     

Antiviral activity and synthesis of quaternized promazine derivatives against HSV-1

N-(4-chlorobenzyl)triflupromazinium chloride, a known antitubercular agent, has been found to also be active against HSV-1. A preliminary structure-activity relation has been explored to determine which groups are crucial to viral inhibition. Antiviral assessments such as GFP reduction, plaque reduction, treatment timing and wash-out studies have also been probed to determine a mode of action for QPD-1. Based on this preliminary data, it appears that QPD-1 is a reversible inhibitor, suspected to inhibit early stages of viral replication of HSV-1 at 50μM, equipotent to acyclovir.     

Conserved C-terminal domain of spider tubuliform spidroin 1 contributes to extensibility in synthetic fibers

Spider silk is renowned for its extraordinary mechanical properties, having a balance of high tensile strength and extensibility. To date, the majority of studies have focused on the production of dragline silks from synthetic spider silk gene products. Here we report the first mechanical analysis of synthetic egg case silk fibers spun from the Latrodectus hesperus tubuliform silk proteins, TuSp1 and ECP-2. We provide evidence that recombinant ECP-2 proteins can be spun into fibers that display mechanical properties similar to other synthetic spider silks. We also demonstrate that silks spun from recombinant thioredoxin-TuSp1 fusion proteins that contain the conserved C-terminal domain exhibit increased extensibility and toughness when compared to the identical fibers spun from fusion proteins lacking the C-terminus. Mechanical analyses reveal that the properties of synthetic tubuliform silks can be modulated by altering the postspin draw ratios of the fibers. Fibers subject to increased draw ratios showed elevated tensile strength and decreased extensibility but maintained constant toughness. Wide-angle X-ray diffraction studies indicate that postdrawn fibers containing the C-terminal domain of TuSp1 have more amorphous content when compared to fibers lacking the C-terminus. Taken together, these studies demonstrate that recombinant tubuliform spidroins that contain the conserved C-terminal domain with embedded protein tags can be effectively spun into fibers, resulting in similar tensile strength but increased extensibility relative to nontagged recombinant dragline silk proteins spun from equivalently sized proteins.