Variety Of Biological Functions (variety + of_biological_function)

Distribution by Scientific Domains

Selected Abstracts

Macrophage migration inhibitor factor (MIF) can induce oxidative injury and apoptotic cell death of spinal cord neurons

M. Toborek
MIF is a cytokine produced by a variety of cells and tissues including the CNS. It can exert a variety of biological functions, such as induction of inflammatory responses and counterregulation of glucocorticoid effects. However, the role of MIF in the pathogenesis of spinal cord trauma is not fully understood. Therefore, the aim of the present study was to evaluate the cellular effects of MIF in cultured spinal cord neurons. A 3-h exposure to MIF significantly enhanced intracellular calcium levels; an effect which was prevented by TMB-8, an antagonist of the IP3 receptor. In addition, MIF treatment increased oxidative stress, decreased viability of spinal cord neurons, increased LDH release and stimulated apoptosis. These results suggest that MIF may play an important role in secondary spinal cord injury. Acknowledgements:, Supported by grants from KSCHIRT and Philip Morris External Research Program. [source]

The evolving role of platelets in inflammation

A. S. Weyrich
Summary., Platelets are small in size and simple in structure. Nevertheless, these anucleate cytoplasts utilize complex molecular systems to regulate a variety of biological functions. Here we review evolutionary paths, traditional roles, and previously unrecognized biological capacities of platelets that interface thrombosis with inflammation and potentially identify new roles in inflammatory diseases. [source]

Nitric oxide and ovarian function

Masa-aki HATTORI
ABSTRACT Nitric oxide (NO) is synthesized by three NO synthases, designated as NOS-1, NOS-2, and NOS-3, with distinct features and localization. Nitric oxide and the reactive oxygen species generated from NO react with a wide variety of biomolecules such as DNA, transcription factors, enzymes, cytokines, and membrane receptors in NO synthesized cells and nearby cells to mediate a variety of biological functions. Nitric oxide synthase-2 and NOS-3 are expressed in the ovary during folliculogenesis and luteinization. Nitric oxide functions as an important modulator for folliculogenesis and atresia, steroidogenesis, prostaglandin biosynthesis, ovulation, luteolysis, and oocyte maturation. Nitric oxide synthase-3 is also localized in the porcine oocytes of the primordial follicles as well as in large follicles. It has been proved that NO is involved in intracellular signaling for oocyte growth and maturation at the pre-ovulatory stage. [source]

Bracovirus gene products are highly divergent from insect proteins

Annie Bézier
Abstract Recently, several polydnavirus (PDV) genomes have been completely sequenced. The dsDNA circles enclosed in virus particles and injected by wasps into caterpillars appear to mainly encode virulence factors potentially involved in altering host immunity and/or development, thereby allowing the survival of the parasitoid larvae within the host tissues. Parasitoid wasps generally inject virulence factors produced in the venom gland. As PDV genomes are inherited vertically by wasps through a proviral form, wasp virulence genes may have been transferred to this chromosomal form, leading to their incorporation into virus particles. Indeed, many gene products from Cotesia congregata bracovirus (CcBV), such as PTPs, I,B-like, and cystatins, contain protein domains conserved in metazoans. Surprisingly however, CcBV virulence gene products are not more closely related to insect proteins than to human proteins. To determine whether the distance between CcBV and insect proteins is a specific feature of BV proteins or simply reflects a general high divergence of parasitoid wasp products, which might be due to parasitic lifestyle, we have analyzed the sequences of wasp genes obtained from a cDNA library. Wasp sequences having a high similarity with Apis mellifera genes involved in a variety of biological functions could be identified indicating that the high level of divergence observed for BV products is a hallmark of these viral proteins. We discuss how this divergence might be explained in the context of the current hypotheses on the origin and evolution of wasp-bracovirus associations. Arch. Insect Biochem. Physiol. 67:172,187, 2008. © 2008 Wiley-Liss, Inc. [source]

Structure of recombinant human cyclophilin J, a novel member of the cyclophilin family

Li-Li Huang
Cyclophilins (CyPs) are a large class of highly conserved ubiquitous peptidyl-prolyl cis,trans isomerases. CyPs have also been identified as being a specific receptor for the immunosuppressive drug cyclosporin A and are involved in a variety of biological functions. CyPJ is a novel member of the CyP family and human CyPJ (hCyPJ) is the protein encoded by a cyclophilin-like gene from human foetal brain, which shows 50% sequence identity to human cyclophilin A (hCyPA). Recombinant hCyPJ was expressed in Escherichia coli and purified. The three-dimensional structure of hCyPJ has been determined by molecular replacement using the hCyPA structure as the search model and has been refined at 2.6,Ĺ resolution. The hCyPJ molecule contains four helices and one ,-barrel composed of eight antiparallel ,-strands. The overall secondary and tertiary structures of hCyPJ are similar to those of hCyPA, but hCyPJ contains an additional disulfide bridge and four segments with conformations that are strikingly different from those of hCyPA. His43 and Gln52 of hCyPJ are expected to be the active sites based on sequence alignment with hCyPA. The hCyPJ structure shows a conserved water molecule close to His43 and Gln52 which appears to support the solvent-assisted mechanism. [source]

The biomolecule ubiquinone exerts a variety of biological functions,

BIOFACTORS, Issue 1-4 2003
Hans Nohl
Abstract The chemistry of ubiquinone allows reversible addition of single electrons and protons. This unique property is used in nature for aerobic energy gain, for unilateral proton accumulation, for the generation of reactive oxygen species involved in physiological signaling and a variety of pathophysiological events. Since several years ubiquinone is also considered to play a major role in the control of lipid peroxidation, since this lipophilic biomolecule was recognized to recycle ,-tocopherol radicals back to the chain-breaking form, vitamin E. Ubiquinone is therefore a biomolecule which has increasingly focused the interest of many research groups due to its alternative pro- and antioxidant activity. We have intensively investigated the role of ubiquinone as prooxidant in mitochondria and will present experimental evidences on conditions required for this function, we will also show that lysosomal ubiquinone has a double function as proton translocator and radical source under certain metabolic conditions. Furthermore, we have addressed the antioxidant role of ubiquinone and found that the efficiency of this activity is widely dependent on the type of biomembrane where ubiquinone exerts its chain-breaking activity. [source]

Single-molecule pair studies of the interactions of the ,-GalNAc (Tn-antigen) form of porcine submaxillary mucin with soybean agglutinin

BIOPOLYMERS, Issue 9 2009
Marit Sletmoen
Abstract Mucins form a group of heavily O -glycosylated biologically important glycoproteins that are involved in a variety of biological functions, including modulating immune response, inflammation, and adhesion. Mucins are also involved in cancer and metastasis and often express diagnostic cancer antigens. Recently, a modified porcine submaxillary mucin (Tn-PSM) containing GalNAc,1- O -Ser/Thr residues was shown to bind to soybean agglutinin (SBA) with ,106 -fold enhanced affinity relative to GalNAc,1- O -Ser, the pancarcinoma carbohydrate antigen. In this study, dynamic force spectroscopy is used to investigate molecular pairs of SBA and Tn-PSM. A number of force jumps that demonstrate unbinding or rebinding events were observed up to a distance equal to 2.0 ,m, consistent with the length of the mucin chain. The unbinding force increased from 103 to 402 pN with increasing force loading rate. The position of the activation barrier in the energy landscape of the interaction was 0.1 nm. The lifetime of the SBA,TnPSM complex in the absence of applied force was determined to be in the range 1.3,1.9 s. Kinetic parameters describing the rate of dissociation of other sugar lectin interactions are in the range 3.3 × 10,3,2.5 × 10,3 s. The long lifetime of the SBA-TnPSM complex is compatible with a binding model in which lectin molecules "bind and jump" from ,-GalNAc residue to ,-GalNAc residue along the polypeptide chain of Tn-PSM before dissociating. These findings have important implications for the molecular recognition properties of mucins. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 719,728, 2009. This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at [source]