Home About us Contact
|
Home About us Contact | ||
|
|
||
Gland Proteins (gland + protein)
Selected AbstractsAegyptin displays high-affinity for the von Willebrand factor binding site (RGQOGVMGF) in collagen and inhibits carotid thrombus formation in vivoFEBS JOURNAL, Issue 2 2010Eric Calvo Aegyptin is a 30 kDa mosquito salivary gland protein that binds to collagen and inhibits platelet aggregation. We have studied the biophysical properties of aegyptin and its mechanism of action. Light-scattering plot showed that aegyptin has an elongated monomeric form, which explains the apparent molecular mass of 110 kDa estimated by gel-filtration chromatography. Surface plasmon resonance identified the sequence RGQOGVMGF (where O is hydroxyproline) that mediates collagen interaction with von Willebrand factor (vWF) as a high-affinity binding site for aegyptin, with a KD of approximately 5 nm. Additionally, aegyptin interacts with the linear peptide RGQPGVMGF and heat-denatured collagen, indicating that the triple helix and hydroxyproline are not a prerequisite for binding. However, aegyptin does not interact with scrambled RGQPGVMGF peptide. Aegyptin also recognizes the peptides (GPO)10 and GFOGER with low affinity (,m range), which respectively represent glycoprotein VI and integrin ,2,1 binding sites in collagen. Truncated forms of aegyptin were engineered, and the C-terminus fragment was shown to interact with collagen and to attenuate platelet aggregation. In addition, aegyptin prevents laser-induced carotid thrombus formation in the presence of Rose Bengal in vivo, without significant bleeding in rats. In conclusion, aegyptin interacts with distinct binding sites in collagen, and is useful tool to inhibit platelet,collagen interaction in vitro and in vivo. Structured digital abstract ,,MINT-7299280, MINT-7299290: Collagen (uniprotkb:P02461) binds (MI:0407) to Aegyptin (uniprotkb:O01949) by enzyme linked immunosorbent assay (MI:0411) ,,MINT-7298991, MINT-7299153, MINT-7299208: Collagen (uniprotkb:P02452) binds (MI:0407) to Aegyptin (uniprotkb:O01949) by surface plasmon resonance (MI:0107) ,,MINT-7299266: Collagen (uniprotkb:P02452) binds (MI:0407) to Aegyptin (uniprotkb:O01949) by fluorescence microscopy (MI:0416) ,,MINT-7299256: Collagen (uniprotkb:P02452) binds (MI:0407) to Aegyptin (uniprotkb:O01949) by solid phase assay (MI:0892) [source] Molecular characterization of two novel milk proteins in the tsetse fly (Glossina morsitans morsitans)INSECT MOLECULAR BIOLOGY, Issue 2 2010G. Yang Abstract Purpose: Milk proteins are an essential component of viviparous reproduction in the tsetse fly. Milk proteins are synthesized in and secreted from the milk gland tissue and constitute 50% of the secretions from which the intrauterine larva derives its nourishment. To understand milk protein function and regulation during viviparous reproduction, milk proteins need to be identified and characterized. Methods: Two putative unknown secretory proteins (GmmMGP2 and GmmMGP3) were selected by bioinformatic analysis of tissue specific tsetse cDNA libraries. RT-PCR analysis was performed to verify their milk gland/fat body specific expression profile. Detailed characterization of developmental and tissue specific expression of these proteins was performed by northern blot analysis and fluorescent in situ hybridization. Functional analysis of the milk gland proteins during the tsetse gonotrophic cycle was performed using RNA interference (RNAi). Results: The predicted proteins from gmmmgp2 and gmmmgp3 are small ,22 kD and contain a high proportion of hydrophobic amino acids and potential phosphorylation sites. Expression of both genes is tissue specific to the secretory cells of the milk gland. Transcript abundance for both genes increases over the course of intrauterine larval development and parallels that of gmmmgp, a well characterized milk protein gene considered to be the major milk protein. Phenotypic analysis of flies after RNA interference treatment revealed a significant effect upon fecundity in the gmmmgp2 knockdown flies, but not the gmmmgp3 flies. Knockdown of gmmmgp2 resulted in disruption of ovulation and consequent oocyte accumulation and degradation. Gmmmgp2 knockdown also had a significant impact on fly mortality. Conclusions: This work identifies two novel genes, the proteins of which appear to function in response to intrauterine larvigenesis in tsetse. These proteins may be nutritional components of the milk secretions provided to the larva from the mother. Phenotypic data from knockdown of gmmmgp2 suggests that this protein may also have a regulatory function given the defect in ovulation observed in knockdown flies. Further analysis of these genes will be important (in conjunction with other milk proteins) for identification of transcriptional regulation mechanisms that direct milk gland/pregnancy specific gene expression. [source] Identification and isolation of cDNA clones encoding the abundant secreted proteins in the saliva proteome of Culicoides nubeculosusINSECT MOLECULAR BIOLOGY, Issue 3 2009C. L. Russell Abstract Culicoides spp. are vectors of several infectious diseases of veterinary importance and a major cause of allergy in horses and other livestock. Their saliva contains a number of proteins which enable blood feeding, enhance disease transmission and act as allergens. We report the construction of a novel cDNA library from Culicoides nubeculosus linked to the analysis of abundant salivary gland proteins by mass spectrometry. Fifty-four novel proteins sequences are described including those of the enzymes maltase, hyaluronidase and two serine proteases demonstrated to be present in Culicoides salivary glands, as well as several members of the D7 family and protease inhibitors with putative anticoagulant activity. In addition, several families of abundant proteins with unknown function were identified including some of the major candidate allergens that cause insect bite hypersensitivity in horses. [source] The seminal fluid proteome of the honeybee Apis melliferaPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 8 2009Boris Baer Dr. Abstract Ejaculates contain sperm but also seminal fluid, which is increasingly recognized to be of central importance for reproductive success. However, a detailed biochemical composition and physiological understanding of seminal fluid is still elusive. We have used MS to identify the 57 most abundant proteins within the ejaculated seminal fluid of the honeybee Apis mellifera. Their amino acid sequences revealed the presence of diverse functional categories of enzymes, regulators and structural proteins. A number have known or predicted roles in maintaining sperm viability, protecting sperm from microbial infections or interacting with the physiology of the female. A range of putative glycoproteins or glycosylation enzymes were detected among the 57, subsequent fluorescent staining of glycolysation revealed several prominant glycoproteins in seminal fluid, while no glycoproteins were detected in sperm samples. Many of the abundant proteins that accumulate in the seminal fluid did not contain predictable tags for secretion for the cell. Comparison of the honeybee seminal fluid proteins with Drosophila seminal fluid proteins (including secreted accessory gland proteins known as ACPs), and with the human seminal fluid proteome revealed the bee protein set contains a range of newly identified seminal fluid proteins and we noted more similarity of the bee protein set with the current human seminal fluid protein set than with the known Drosophila seminal fluid proteins. The honeybee seminal fluid proteome thus represents an important addition to available data for comparative studies of seminal fluid proteomes in insects. [source] Micro-injection of lygus salivary gland proteins to simulate feeding damage in alfalfa and cotton flowers ,ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 2 2005Kenneth A. Shackel Abstract Alfalfa and cotton flowers were pierced with small glass capillaries of an overall size and shape similar to that of Lygus stylets, and injected with small quantities (6 to 100 nL) of solutions that contained Lygus salivary enzymes. Crude and partially purified protein solutions from Lygus heads and isolated salivary glands showed substantial polygalacturonase (PG) activity, as has been previously reported. Following injection with both crude and partially purified protein solutions, as well as with pure fungal and bacterial PGs, flowers of both alfalfa and cotton exhibited damage similar to that caused by Lygus feeding. Injection with the same volume of a buffer control as well as a buffer control containing BSA at a comparable protein concentration (approximately 6 ,g/mL) showed no symptoms. These results are consistent with a previously suggested hypothesis that the extensive tissue damage caused by Lygus feeding is primarily due to the action of the PG enzyme on the host tissue, rather than to mechanical damage caused by the insect stylet. Substantial genotypic variation for a PG inhibiting protein (PGIP) exists in alfalfa and cotton. We, therefore, suggest that breeding and selection for increased native PGIP levels, or transformation with genes encoding PGIP from other plant species, may be of value in obtaining alfalfa and cotton varieties that are more resistant to Lygus feeding damage. Arch. Insect Biochem. Physiol. 58:69,83, 2005. © 2005 Wiley-Liss, Inc. [source] Multiple barriers to gene exchange in a field cricket hybrid zoneBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 2 2009LUANA S. MAROJA Data on patterns of variation within hybrid zones, combined with studies of life history, mate choice, and hybrid performance, allow estimates of the contribution of different pre-zygotic and post-zygotic barriers to reproductive isolation. We examine the role of behavioural barriers to gene exchange in the maintenance of a hybrid zone between North American field crickets Gryllus firmus and Gryllus pennsylvanicus. We consider these barriers in the context of previous studies that documented temporal and ecological isolation and a one-way post-mating incompatibility (i.e. G. firmus females do not produce offspring when they mate only with heterospecific males). Based on no-choice mating experiments in the laboratory, we demonstrate strong behavioural pre-mating barriers between the two species, but no apparent fecundity or fertility costs for G. firmus females when they mate with both conspecific and heterospecific males. Furthermore, we show that G. firmus females do not discriminate between hybrids and conspecifics, whereas G. pennsylvanicus females do. This observation could explain the asymmetric allele introgression observed in the hybrid zone. We also document a failure of heterospecific males to induce normal oviposition in G. firmus females, which may be due to rapid evolution of accessory gland proteins and may serve as an additional barrier to gene exchange. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 390,402. [source] | |||||||||||||