Canatoxin, a toxic protein from jack beans (Canavalia ensiformis), is a variant form of urease (EC 3.5.1.5): biological effects of urease independent of its ureolytic activity

2001 ◽  
Vol 360 (1) ◽  
pp. 217-224 ◽  
Author(s):  
Cristian FOLLMER ◽  
Grace B. S. BARCELLOS ◽  
Russolina B. ZINGALI ◽  
Olga L. T. MACHADO ◽  
Elias W. ALVES ◽  
...  
Keyword(s):  
Blood Platelets ◽  
Biological Effects ◽  
Enzymic Activity ◽  
Variant Form ◽  
Native Form ◽  
Toxic Protein ◽  
Canavalia Ensiformis ◽  
Covalently Linked ◽  
First Time

Canatoxin is a toxic protein from Canavalia ensiformis seeds, lethal to mice (LD50 = 2mg/kg) and insects. Further characterization of canatoxin showed that its main native form (184kDa) is a non-covalently linked dimer of a 95kDa polypeptide containing zinc and nickel. Partial sequencing of internal peptides indicated homology with urease (EC 3.5.1.5) from the same seed. Canatoxin has approx. 30% of urease's activity for urea, and Km of 2–7mM. The proteins differ in their affinities for metal ions and were separated by affinity chromatography on a Zn2+ matrix. Similar to canatoxin, urease activates blood platelets and interacts with glycoconjugates. In contrast with canatoxin, no lethality was seen in mice injected with urease (10mg/kg). Pretreatment with p-hydroxymercuribenzoate irreversibly abolished the ureolytic activity of both proteins. On the other hand, p-hydroxymercuribenzoate-treated canatoxin was still lethal to mice, and both treated proteins were fully active in promoting platelet aggregation and binding to glycoconjugates. Taken together, our data indicate that canatoxin is a variant form of urease. Moreover, we show for the first time that these proteins display several biological effects that are unrelated to their enzymic activity for urea.

scholarly journals Canatoxin, a toxic protein from jack beans (Canavalia ensiformis), is a variant form of urease (EC 3.5.1.5): biological effects of urease independent of its ureolytic activity

2001 ◽  
Vol 360 (1) ◽  
pp. 217 ◽  
Author(s):  
Cristian FOLLMER ◽  
Grace B.S. BARCELLOS ◽  
Russolina B. ZINGALI ◽  
Olga L.T. MACHADO ◽  
Elias W. ALVES ◽  
...  
Keyword(s):  
Biological Effects ◽  
Variant Form ◽  
Toxic Protein ◽  
Canavalia Ensiformis

scholarly journals Identification and Characterization of α-Glucosidase Inhibition Flavonol Glycosides from Jack Bean (Canavalia ensiformis (L.) DC

Molecules ◽  
2020 ◽  
Vol 25 (11) ◽  
pp. 2481
Author(s):  
Anita M. Sutedja ◽  
Emiko Yanase ◽  
Irmanida Batubara ◽  
Dedi Fardiaz ◽  
Hanifah N. Lioe
Keyword(s):  
2D Nmr ◽  
The Other ◽  
Inhibition Activity ◽  
Jack Bean ◽  
Canavalia Ensiformis ◽  
Kaempferol Glycosides ◽  
Uv Visible ◽  
First Time ◽  
Identification And Characterization

Although the intake of jack bean (Canavalia ensiformis (L.) DC.), an underutilized tropical legume, can potentially decrease the risk of several chronic diseases, not much effort has been directed at profiling the polyphenolics contained therein. Hence, this work aimed to identify and quantify the dominant jack bean polyphenolics, which are believed to have antioxidant and other bioactivities. Four major compounds were detected and identified as kaempferol glycosides with three or four glycoside units. Their structures were established based on UV-visible, 1D, 2D NMR, and HR-ESI-MS analyses. Specifically, kaempferol 3-O-α-l-rhamnopyranosyl (1→6)- β-d-glucopyranosyl (1→2)-β-d-galactopyranosyl-7-O-[3-O-o-anisoyl]-α-l-rhamnopyranoside was detected for the first time, while the other three compounds have already been described in plants other than jack bean. This new compound was found to have a higher α-glucosidase inhibition activity compared to acarbose.

scholarly journals Identification and Molecular Characterization of Novel Mycoviruses in Saccharomyces and Non-Saccharomyces Yeasts of Oenological Interest

Viruses ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 52
Author(s):  
Dalila Crucitti ◽  
Marco Chiapello ◽  
Daniele Oliva ◽  
Marco Forgia ◽  
Massimo Turina ◽  
...  
Keyword(s):  
Biological Effects ◽  
Single Infection ◽  
Mixed Infections ◽  
Wine Yeasts ◽  
Viral Origin ◽  
Related Sequence ◽  
Natural Hosts ◽  
First Time ◽  
Saccharomyces Yeasts

Wine yeasts can be natural hosts for dsRNA, ssRNA viruses and retrotransposon elements. In this study, high-throughput RNA sequencing combined with bioinformatic analyses unveiled the virome associated to 16 Saccharomyces cerevisiae and 8 non-Saccharomyces strains of oenological interest. Results showed the presence of six viruses and two satellite dsRNAs from four different families, two of which—Partitiviridae and Mitoviridae—were not reported before in yeasts, as well as two ORFan contigs of viral origin. According to phylogenetic analysis, four new putative mycoviruses distributed in Totivirus, Cryspovirus, and Mitovirus genera were identified. The majority of commercial S. cerevisiae strains were confirmed to be the host for helper L-A type totiviruses and satellite M dsRNAs associated with the killer phenotype, both in single and mixed infections with L-BC totiviruses, and two viral sequences belonging to a new cryspovirus putative species discovered here for the first time. Moreover, single infection by a narnavirus 20S-related sequence was also found in one S. cerevisiae strain. Considering the non-Saccharomyces yeasts, Starmerella bacillaris hosted four RNAs of viral origin—two clustering in Totivirus and Mitovirus genera, and two ORFans with putative satellite behavior. This study confirmed the infection of wine yeasts by viruses associated with useful technological characteristics and demonstrated the presence of complex mixed infections with unpredictable biological effects.

scholarly journals Characterization of Neoplastic Cells in the Cystic Space of Invasive Micropapillary Carcinoma of the Canine Mammary Gland.

2020 ◽  
Author(s):  
Michele Angela Rodrigues ◽  
Andre L. Caldeira-Brant ◽  
Dawidson Assis Gomes ◽  
Tatiany L. Silveira ◽  
Hélio Chiarini-Garcia ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Stromal Cells ◽  
Ductal Carcinoma ◽  
Variant Form ◽  
Invasive Micropapillary Carcinoma ◽  
Micropapillary Carcinoma ◽  
Cystic Space ◽  
First Time ◽  
Canine Mammary Gland

Abstract Background: Invasive micropapillary carcinoma (IMPC) is a rare breast malignant tumor and a variant form of invasive ductal carcinoma that is an aggressive neoplasm of the canine mammary gland and the human breast. There is a progressed recognition of the importance of the tumor microenvironment in cancer development, but little is known about cell types expressed in the cystic space of canine IMPC. This study aimed to investigate the neoplastic and stromal cells surrounding the cystic space in IMPC. Methods: It was used immunohistochemistry (IHC), immunofluorescence (IF), super-resolution microscope and transmission electron microscopy (TEM) to access the localization and morphology of both stromal cells and epithelial cells in canine IMPC cystic areas.Results: Cells surrounding the cystic space in IMPC were positive for the mesenchymal marker's alpha-smooth muscle actin (aSMA), Vimentin, and S100A4. Furthermore, myoepithelial cell marker p63 was negative on IMPC. Tumoral reversal polarity was observed using MUC1 for the first time in IMPC from the canine mammary gland. MUC1 is known to have a role in lumen formation and has an inhibitory role in the cell to stroma interaction. TEM showed that cells lining the IMPC cystic space were modified myoepithelial cells. Conclusion: The present work demonstrates, for the first time, a characterization of the cystic space compound on IMPC from the canine mammary gland. These findings could be useful to understand better the cellular microenvironment in invasive tumors of the mammary gland to improve cancer treatment.

scholarly journals Isolation and characterization of novel lectins from Canavalia ensiformis DC and Dioclea grandiflora Mart. ex Benth. seeds

2005 ◽  
Vol 17 (3) ◽  
pp. 315-324 ◽  
Author(s):  
Luz Marina Melgarejo ◽  
Nohora Vega ◽  
Gerardo Pérez
Keyword(s):  
Gel Filtration ◽  
Hydrophobic Interaction Chromatography ◽  
Canavalia Ensiformis ◽  
Human Red Blood Cells ◽  
Isolation And Characterization ◽  
Dioclea Grandiflora ◽  
Covalently Linked ◽  
Type 3

Two lectins were isolated from Canavalia ensiformis and Dioclea grandiflora seeds. Gel filtration produced a fraction corresponding to Con A or D. grandiflora lectin while erythroagglutination assays revealed a distinct fraction presenting a lectin that agglutinates human red blood cells (RBCs) but not rabbit RBCs. Hydrophobic interaction chromatography showed that the latter fraction yielded a protein that readily agglutinates human erythrocytes; the lectin was also purified by affinity chromatography on Lac-Sepharose showing similar properties to that of the Phenyl-Sepharose-purified lectin. Despite minor differences (carbohydrate content or A1%1cm), the two lectins showed similar molecular properties in that they consisted of two non-covalently linked monomers having a Mr of 29-30 kDa and their pI values indicated that both lectins were slightly acidic proteins. The C. ensiformis lectin (CEL-II) and D. grandiflora lectin (DGL-II) specifically recognised the H-type 2 blood group (alpha-L-Fuc (1-2)-beta-D-Gal (1-4)-beta-D-GlcNAc-O-R), while binding to H-type 1, H-type 3, H-type 4, Leª or Le y was weaker. Carbohydrate inhibition of erythroagglutination showed that simple sugars were weakly recognised by the lectins, if at all. The N-terminal region presented a unique sequence hitherto found only in some Diocleinae lectins (designated type II). The overall results confirmed the existence of a second distinct lectin type, phylogenetically close to Diocleinae species. The data indicate a functional similarity among lectins of this type which possesses distinctive characteristics differentiating them from "classical" Man/Glc lectins.

scholarly journals Clathrin mediates endocytosis of progastrin and activates MAPKs: role of cell surface annexin A2

2012 ◽  
Vol 302 (7) ◽  
pp. G712-G722 ◽  
Author(s):  
Shubhashish Sarkar ◽  
Carla Kantara ◽  
Pomila Singh
Keyword(s):  
Cell Surface ◽  
Biological Effects ◽  
Annexin A2 ◽  
Intestinal Cells ◽  
Target Cells ◽  
Coated Pits ◽  
Colon Cancers ◽  
Tumorigenic Potential ◽  
Covalently Linked ◽  
First Time

Cell-surface-associated annexin A2 (CS-ANXA2) is a nonconventional “receptor” for progastrin; expression levels of both are elevated in colon cancers, and downregulation of either reduces tumorigenic potential of cells. We recently reported internalization of progastrin in target cells. Here, mechanisms mediating internalization of progastrin were examined. Initially, we confirmed that cell-surface ANXA2 mediates binding and internalization of progastrin in intestinal cells. Progastrin, covalently linked to sepharose beads, failed to activate p38MAPK/ERKs, suggesting internalization of progastrin was required for eliciting biological effects; importantly annexin A2 expression and availability of CS-ANXA2 were required for internalization of progastrin. Clathrin expression and formation of clathrin-coated pits were critically required for endocytotic internalization of progastrin; in the absence of clathrin, progastrin failed to activate p38MAPK/ERKs. Downregulation of caveolin had no effect on binding or internalization of progastrin. We therefore demonstrate for the first time that progastrin binds CS-ANXA2 and is rapidly internalized via clathrin-mediated endocytotic pathway, resulting in activation of MAPKinases. Targeting clathrin-mediated endocytosis of progastrin may thus inhibit previously reported co-carcinogenic/tumorigenic effects of progastrin on intestinal cells.

scholarly journals Molecular Characterization of a Glucose-Inhibited Division Gene, gidA, That Regulates Cytotoxic Enterotoxin of Aeromonas hydrophila

2004 ◽  
Vol 72 (2) ◽  
pp. 1084-1095 ◽  
Author(s):  
Jian Sha ◽  
E. V. Kozlova ◽  
A. A. Fadl ◽  
J. P. Olano ◽  
C. W. Houston ◽  
...  
Keyword(s):  
Virulence Factor ◽  
Aeromonas Hydrophila ◽  
Histopathological Examination ◽  
Biological Effects ◽  
Similar Reduction ◽  
Reading Frame ◽  
Transposon Insertion ◽  
Isogenic Mutants ◽  
First Time

ABSTRACT By using a mini-transposon, we obtained two mutated strains of a diarrheal isolate, SSU, of Aeromonas hydrophila that exhibited a 50 to 53% reduction in the hemolytic activity and 83 to 87% less cytotoxic activity associated with the cytotoxic enterotoxin (Act). Act is a potent virulence factor of A. hydrophila and has been shown to contribute significantly to the development of both diarrhea and septicemia in animal models. Subsequent cloning and DNA sequence analysis revealed that transposon insertion occurred at different locations in these two mutants within the same 1,890-bp open reading frame for the glucose-inhibited division gene (gidA). A similar reduction in hemolytic (46%) and cytotoxic (81%) activity of Act was noted in the gidA isogenic mutant of A. hydrophila that was generated by marker exchange mutagenesis. Northern blot analysis revealed that the transcription of the cytotoxic enterotoxin gene (act) was not altered in the gidA transposon and isogenic mutants. However, by generating a chromosomal act::alkaline phosphatase gene (phoA) reporter construct, we demonstrated significantly reduced phosphatase activity in these mutants, indicating the effect of glucose-inhibited division (GidA) protein in modulating act gene expression at the translational level. The biological effects of Act in the gidA mutants were restored by complementation. The virulence of the gidA mutants in mice was dramatically reduced compared to the those of the wild-type (WT) and complemented strains of A. hydrophila. The histopathological examination of lungs, in particular, indicated severe congestion, alveolar hemorrhage, and acute inflammatory infiltrate in the interstitial compartment and the alveolar spaces when mice were infected with the WT and complemented strains. Minimal-to-mild changes were noted in the lungs with the gidA mutants. Taken together, our data indicate for the first time that GidA regulates the most-potent virulence factor of A. hydrophila, Act.

scholarly journals Biochemical Isolation and Characterization of Hyaluronidase Enzyme from Venom of Egyptian Honey Bee Apis Mellifera Lamarckii

2020 ◽  
Vol 64 (1) ◽  
pp. 153-164
Author(s):  
Mohammed M. Abdel-Monsef ◽  
Hind A. Zidan ◽  
Doaa A. Darwish ◽  
Hassan M. Masoud ◽  
Mohamed S. Helmy ◽  
...  
Keyword(s):  
Specific Activity ◽  
Deae Cellulose ◽  
Bee Venom ◽  
Native Form ◽  
Native Page ◽  
Isolation And Characterization ◽  
Sds Page ◽  
Wide Range ◽  
First Time

AbstractThe hyaluronidase enzyme has been used in many such fields of medicine as ophthalmology, orthopaedia, internal medicine, gynecology, surgery, oncology and dermatology. In this study, the hyaluronidase enzyme was purified and characterized for the first time from Egyptian bee venom homogeneously using DEAE-cellulose and Sephacryl S-300 columns. Bee venom hyaluronidase specific activity was 411.7 units/mg protein with 49.9% yield and 3.23-fold purification. The molecular weight of the purified bee venom hyaluronidase native form was 37 kDa. The purified enzyme was found homogeneous on native PAGE and SDS-PAGE, with two congruent subunits of 18.4 kDa and isoelectric point (pI) of 8.6–8.8. The enzyme was found to be stable over a wide range of temperature (20–60°C) and pH (4.5–6.5), and its optimum activity at 37°C, pH 5.4 and 0.15 M NaCl. Km for bee venom hyaluronidase was 0.029 mg/ml hyaluronic acid and its activity was elevated in presence of MgCl2 and ZnCl2 and lowered in presence of FeCl2. Heparin inhibited the hyaluronidase enzyme noncompetitively with a Ki value of 2.9 units heparin and one binding site on the enzyme molecule.

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