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At least 19 recordsLinked to original sources
PubMed2000

Molecular characterization of human tensin.

Tensin is a focal-adhesion molecule that binds to actin filaments and interacts with phosphotyrosine-containing proteins. To analyse tensin's function in mammals, we have cloned tensin cDNAs from human and cow. The isolated approx. 7.7-kb human cDNA contains an open reading frame encoding 1735 amino acid residues. The amino acid sequence of human tensin shares 60% identity with chicken tensin, and contains all the structural features described previously in chicken tensin. This includes the actin-binding domains, the Src homology domain 2, and the region similar to a tumour suppressor, PTEN. Two major differences between human and chicken tensin are (i) the lack of the first 54 residues present in chicken tensin, and (ii) the addition of 34- and 38-residue inserts in human and bovine tensin. In addition, our interspecies sequencing data have uncovered the presence of a glutamine/CAG repeat that appears to have expanded in the course of evolution. Northern-blot analysis reveals a 10-kb message in most of the human tissues examined. An additional 9-kb message is detected in heart and skeletal muscles. The molecular mass predicted from the human cDNA is 185 kDa, although both endogenous and recombinant human tensin migrate as 220-kDa proteins on SDS/PAGE. The discrepancy is due to the unusually low electrophoretic mobility of the central region of the tensin polypeptide (residues 306-981). A survey of human prostate and breast cancer cell lines by Western-blot analysis shows a lack of tensin expression in most cancer cell lines, whereas these lines express considerable amounts of focal-adhesion molecules such as talin and focal-adhesion kinase. Finally, tensin is rapidly cleaved by a focal-adhesion protease, calpain II. Incubation of cells with a calpain inhibitor, MDL, prevented tensin cleavage and induced morphological change in these cells, suggesting that cleavage of tensin and other focal-adhesion constituents by calpain disrupts maintenance of normal cell shape.

3T3 Cells↗
PubMed2004

Tensin is potentially involved in extracellular matrix production in mesangial cells.

Tensin, a focal adhesion protein, is expressed in renal tubular epithelial cells (TECs). Tensin-null mice develop multiple large cysts in the renal proximal tubules. However, the role of tensin in human glomeruli remains unclear. In this study, we assessed tensin localization in human kidney and interaction between tensin and other adhesion components. In human mesangial cells (MCs) and TECs, we confirmed mRNA and protein expressions of tensin by RT-PCR and immunoprecipitation. In normal kidney, immunohistochemistry revealed that tensin was localized in MCs and parietal epithelial cells as well as TECs. In biopsy specimens, the expression of tensin was significantly increased in areas of mesangial expansion in patients with IgA nephropathy and diabetic nephropathy. These results suggest that the expression of tensin is associated with extracellular matrix (ECM) production. In vitro, immunocytochemistry revealed that MCs express tensin mainly at the ends of actin stress fibers and apparently in the focal adhesion areas. Integrin alpha5, but not alpha1 and alpha3, colocalized with tensin. Vinculin and focal adhesion kinase (FAK) were coprecipitated by tensin, suggesting that tensin can mediate signal transduction between cell and ECM through these molecules. Tensin may play important roles in mesangial ECM production through an adhesion complex with integrin alpha5, FAK, and vinculin.

Diabetic Nephropathies↗
PubMed2003

blistery encodes Drosophila tensin protein and interacts with integrin and the JNK signaling pathway during wing development.

Tensin is an actin-binding protein that is localized in focal adhesions. At focal adhesion sites, tensin participates in the protein complex that establishes transmembrane linkage between the extracellular matrix and cytoskeletal actin filaments. Even though there have been many studies on tensin as an adaptor protein, the role of tensin during development has not yet been clearly elucidated. Thus, this study was designed to dissect the developmental role of tensin by isolating Drosophila tensin mutants and characterizing its role in wing development. The Drosophila tensin loss-of-function mutations resulted in the formation of blisters in the wings, which was due to a defective wing unfolding process. Interestingly, by(1)-the mutant allele of the gene blistery (by)-also showed a blistered wing phenotype, but failed to complement the wing blister phenotype of the Drosophila tensin mutants, and contains Y62N/T163R point mutations in Drosophila tensin coding sequences. These results demonstrate that by encodes Drosophila tensin protein and that the Drosophila tensin mutants are alleles of by. Using a genetic approach, we have demonstrated that tensin interacts with integrin and also with the components of the JNK signaling pathway during wing development; overexpression of by in wing imaginal discs significantly increased JNK activity and induced apoptotic cell death. Collectively, our data suggest that tensin relays signals from the extracellular matrix to the cytoskeleton through interaction with integrin, and through the modulation of the JNK signal transduction pathway during Drosophila wing development.

Animals↗
PubMed2004

Tensin is expressed in glomerular mesangial cells and is related to their attachment to surrounding extracellular matrix.

Glomerular expression of tensin was immunohistochemically studied in normal and diseased rat kidneys to determine whether tensin might be related to specific binding in individual glomerular cells. Normal rat kidneys displayed an intense immunofluorescence reaction for tensin along the basal aspects of proximal and distal tubule cells and parietal epithelial cells of Bowman's capsules. In glomeruli, a positive reaction for tensin was detected only in the mesangial areas. Immunoelectron microscopy revealed a positive reaction in the mesangial cell (MC) processes. RT-PCR and immunoprecipitation demonstrated mRNA and protein levels of tensin in cultured rat MCs. Mesangial tensin expression was decreased when the mesangium was injured by Habu snake venom. During the regenerative process after mesangiolysis, tensin expression was not detected in early-phase proliferating MCs that did not have extracellular matrix (ECM). The expression of tensin recovered in late-phase proliferating MCs, which became attached to regenerated ECM. It appears that tensin is related to MC attachment to surrounding ECM, which suggests that signal transduction regulated by tensin may be related to a specific mechanism of MC matrix regeneration. Furthermore, tensin can act as a marker for rat MCs because the expression of tensin was detected only in MCs in glomeruli.

Animals↗
PubMed1994

Molecular cloning of chick cardiac muscle tensin. Full-length cDNA sequence, expression, and characterization.

Here we describe the molecular cloning of 7.1-kilobase cDNA encoding chick cardiac muscle tensin. It contains an open reading frame of 1,744 amino acid (aa) residues. Sequence analysis reveals that, in addition to the previously noted SH2 domain (Davis, S., Lu, M. L., Lo, S. H., Lin, S., Butler, J. A., Druker, B. J., Roberts, T. M., An, Q., and Chen, L. B. (1991) Science 252, 712-715), tensin contains virtually all of the known sequence (362 aa) of insertin, an actin-capping protein that allows actin monomer to be "inserted" (Schroer, E., and Wegner, A. (1985) Eur. J. Biochem. 153, 515-520). Moreover, tensin shares partial homology with actin (46.7% identity in 30 aa), beta-spectrin's actin-binding consensus (40% identity in 26 aa), BCR (40% identity in 25 aa), catenin alpha (35% identity in 45 aa), synapsin Ia (25.6% identity in 156 aa), IL-3 receptor (20.2% identity in 384 aa), and IL-2/EPO receptors (14% identity in 20 aa). Recombinant full-length tensin, tagged with an influenza-derived epitope, was over-expressed by a baculovirus system and purified to apparent homogeneity. It migrates as a 200-kDa protein in SDS-polyacrylamide gel electrophoresis, similar to the native tensin. The structure of the tensin molecule has been characterized by light scattering, electron microscopy, and gel filtration. Nine monoclonal antibodies recognizing different regions of tensin have been prepared and characterized. The epitope-tagged recombinant tensin gene was subcloned into a pRcCMV vector and transfected into NIH 3T3 cells. Immunofluorescence stainings with monoclonal antibodies specific for chick tensin (not cross-reactive with mouse tensin) showed that the expressed protein is indeed localized at focal contacts, as that of native tensin.

3T3 Cells↗
PubMed2005

The cancer chemopreventive agent resveratrol induces tensin, a cell-matrix adhesion protein with signaling and antitumor activities.

During a search to identify resveratrol (3,5,4'-trihydroxy-trans-stilbene, RV) target genes in the human erythroleukemic K562 cell line, we show here that the tensin gene and protein levels are remarkably induced by this dietary polyphenol. Tensin, a cell-matrix adhesion protein binding the integrins and cytoskeletal actin filaments also interacts with PI3-kinase and JNK signaling pathways. Tensin induction by RV is associated with increased K562 cell adhesion to fibronectin, cell spreading and actin polymerization. The same responses were observed in the tensin-deficient MCF7 human breast cancer cell line. In K562 and MCF7 cells treated by RV, tensin was found in punctate and intracytoplasmic areas. In MCF7 epithelial cells, induction of tensin is not exclusively associated with plasma membrane-bound vinculin, suggesting a dual localization of tensin in both focal and fibrillar adhesions. Pharmacological blockade of PI3-kinase and Rho GTPases/Rho-kinase resulted in selective depletion of focal adhesions, disorganization of tensin localization and disruption of stress fibers. RV increased cell motility and attachment to fibronectin in MCF7 cells submitted to mechanical laminar flow stress, and abrogated estrogen-induced MCF7 cancer cell invasion. Our data support the conclusion that induction of tensin by RV contributes to the chemopreventive and anti-invasive activity of this natural dietary compound in tensin-negative and -deficient leukemic cells or epithelioid cancers.

Actins↗
PubMed1997

Progressive kidney degeneration in mice lacking tensin.

Tensin is a focal adhesion phosphoprotein that binds to F-actin and contains a functional Src homology 2 domain. To explore the biological functions of tensin, we cloned the mouse tensin gene, determined its program of expression, and used gene targeting to generate mice lacking tensin. Even though tensin is expressed in many different tissues during embryogenesis, tensin null mice developed normally and appeared healthy postnatally for at least several months. Over time, -/- mice became frail because of abnormalities in their kidneys, an organ that expresses high levels of tensin. Mice with overt signs of weakness exhibited signs of renal failure and possessed multiple large cysts in the proximal kidney tubules, but even in tensin null mice with normal blood analysis, cysts were prevalent. Ultrastructurally, noncystic areas showed typical cell-matrix junctions that readily labeled with antibodies against other focal adhesion molecules. In abnormal regions, cell-matrix junctions were disrupted and tubule cells lacked polarity. Taken together, our data imply that, in the kidney, loss of tensin leads to a weakening, rather than a severing, of focal adhesion. All other tissues appeared normal, suggesting that, in most cases, tensin's diverse functions are redundant and may be compensated for by other focal adhesion proteins.

Animals↗
PubMed1995

Differentiation dependent expression of tensin and cortactin in chicken osteoclasts.

The expression and localization of tensin and cortactin were examined in osteoclast precursors in comparison with isolated osteoclasts on various substrates. Initially, the ability of hen monocytes to differentiate into osteoclasts was evaluated on plastic or glass, and compared to differentiation on bone. Specifically, monocytes were isolated from the medullary bones of egg-laying hens maintained on a Ca-deficient diet. Differentiation was monitored morphologically and by quantitation of the ability to form Howship's lacunae in bone slices or resorb radiolabeled bone particles of 20-53 microns diameter. These cells differentiated into tartrate resistant acid phosphatase (TRAP)-positive, bone resorbing, multinucleated syncytia in the presence of cytosine-1-beta-D-arabinofuranoside in a time dependent manner (day 1-6). Differentiation into osteoclast-like cells was similar whether cultured on plastic, on glass, or on bone. When compared to GAP-DH control levels, tensin and cortactin mRNA levels increased by 7- and 10-fold, respectively, by day 6. Tensin and cortactin protein levels also increased by 6- and 15-fold, respectively, by day 6. Immunofluorescence of differentiating precursors showed that tensin localized between regions of cell to cell contact and colocalized with vinculin in podosomes of osteoclast-like cells and of real osteoclasts. Cortactin immunofluorescence was not detectable in monocytes but localized inside tensin/vinculin podosome structures after fusion into osteoclast-like cells and in freshly isolated osteoclasts. Both tensin and cortactin were associated with attachment complexes used by osteoclast-like cells and osteoclasts to resorb bone. Specifically, punctate cortactin staining was observed inside tensin staining which formed a double ring structure at the membrane/bone interface of resorbing osteoclasts. These data showed that tensin and cortactin can be used as osteoclast differentiation markers, that participate in attachment complexes used to resorb bone, and that tensin may participate in the fusion process of osteoclast precursors.

Animals↗
PubMed1996

Platelet-derived growth factor-induced formation of tensin and phosphoinositide 3-kinase complexes.

Tensin is an SH2 domain-containing cytoskeletal protein that binds to and caps actin filaments. Investigation of signal transduction mechanisms associated with tensin revealed the presence of phosphoinositide 3-kinase (PI 3-kinase) activity in tensin immunoprecipitates from platelet-derived growth factor-treated cells. Association of PI 3-kinase activity with tensin was transitory, and the amount of activity was approximately 1% of the total PI 3-kinase activity found in anti-phosphotyrosine (anti-pY) immunoprecipitates. In vitro, PI 3-kinase activity associated with the SH2 domain of tensin in a platelet-derived growth factor-dependent manner. The optimal phosphopeptide binding specificity of the SH2 domain of tensin was determined to be phospho-Y (E or D), N, (I, V, or F). Synthetic phosphopeptides containing the sequence YENI could specifically block the association of PI 3-kinase activity with tensin in a dose-dependent manner. These results suggest that PI 3-kinase interacts with the cytoskeleton via the SH2 domain of tensin and may play an important role in platelet-derived growth factor-induced cytoskeletal reorganization that is concomitant with cell migration and proliferation.

Amino Acid Sequence↗
PubMed1995

Molecular cloning, expression, and mapping of the high affinity actin-capping domain of chicken cardiac tensin.

Tensin, an actin filament capping protein first purified from chicken gizzard, is localized to various types of adherens junctions in muscle and nonmuscle cells. In this paper, we describe the isolation and sequencing of tensin cDNA from a chicken cardiac library. The 6.3-kb chicken cardiac tensin cDNA encodes an open reading frame of 1,792 amino acids. Mammalian cells transfected with the chicken tensin cDNA expressed a polypeptide of approximately 200 kD recognizable by antibodies to chicken gizzard tensin. The expressed protein was incorporated into focal adhesions and other actin-containing structures in the transfected cells. To map the domain associated with tensin's high affinity, barbed-end F-actin-capping activity, bacterially expressed recombinant fusion proteins containing various segments of tensin were prepared and assayed for activity. The results of these experiments show that the high affinity capping domain (kD = 1.3 nM) lies within amino acid residues R1037-V1169. Additional studies on a shorter construct, S1061-H1145, showed that these 85 residues were sufficient for producing complete inhibition of actin polymerization and depolymerization. While this active domain is located within that of the "insertin" sequence (Weigt, C., A. Gaertner, A. Wegner, H. Korte, and H. E. Meyer. 1992. J. Mol. Biol. 227:593-595), our data showing complete inhibition of polymerization and shift in critical concentration are consistent with a simple barbed-end capping mechanism rather than the "insertin model." Our results also differ from those of a recent report (Lo, S. H., P. A. Janmey, J. H. Hartwig, and L. B. Chen. 1994. J. Cell Biol. 125:1067-1075), which concluded that their recombinant tensin has an "insertin-like" inhibitory effect on barbed-end actin polymerization, and that this activity is attributed to residues T936-R1037 (residues 888-989 in their numbering system). In our study, a fusion construct (N790-K1060) encompassing T936-R1037 had no significant effect on actin polymerization and depolymerization, even at high concentrations.

3T3 Cells↗
PubMed1994

Tensin: a potential link between the cytoskeleton and signal transduction.

Cytoskeletal proteins provide the structural foundation that allows cells to exist in a highly organized manner. Recent evidence suggests that certain cytoskeletal proteins not only maintain structural integrity, but might also be associated with signal transduction and suppression of tumorigenesis. Since the time of the discovery of tensin, a fair amount of data has been gathered which supports the notion that tensin is one such protein possessing these characteristics. In this review, we discuss recent studies that: (1) elucidate a role for tensin in maintenance of cellular structure and signal transduction; (2) implicate tensin as the anchor for actin filaments at the focal adhesion; (3) describe the phosphorylation of tensin; (4) describe potential targets for its Src homology region 2 domain; (5) describe the association between tensin and the nuclear protein p130; and (6) demonstrate that increased tensin expression in a cell line appears to reduce its transformation potential.

Actin Cytoskeleton↗
PubMed2003

Caspase-dependent cleavage of tensin induces disruption of actin cytoskeleton during apoptosis.

Members of both calpain and caspase protease families can degrade several components of focal adhesions, leading to disassembly of these complexes. In this report, we investigated the disappearance of tensin from cell adhesion sites of chicken embryonic fibroblast cells (CEFs) exposed to etoposide and demonstrated that loss of tensin from cell adhesions during etoposide-induced apoptosis may be due to degradation of tensin by caspase-3. Tensin cleavage by caspase-3 at the sequence DYPD(1226)G separates the amino-terminal region containing the actin binding domain and the carboxyl-terminal region containing the SH2 domain. The resultant carboxyl-terminal fragment of tensin is unable to bind phosphoinositide 3-kinase (PI3-kinase) transducing cell survival signaling. We also demonstrated that overexpression of the amino-terminal tensin fragment induced disruption of actin cytoskeleton in chicken embryonic fibroblasts. Therefore, caspase-mediated cleavage of tensin contributes to the disruption of actin organization and interrupts ECM-mediated survival signals through phosphatidylinositol 3-kinase.

Actins↗
PubMed2004

Tensin.

Tensin is a cytoplasmic phosphoprotein that localized to integrin-mediated focal adhesions. It binds to actin filaments and contains a phosphotyrosine-binding (PTB) domain, which interacts with the cytoplasmic tails of beta integrin. These interactions allow tensin to link actin filaments to integrin receptors. In addition, tensin has an Src Homology 2 (SH2) domain capable of interacting with tyrosine-phosphorylated proteins. Furthermore, several factors induce tyrosine phosphorylation of tensin. Thus, tensin functions as a platform for dis/assembly of signaling complexes at focal adhesions by recruiting tyrosine-phosphorylated signaling molecules through the SH2 domain, and also by providing interaction sites for other SH2-containing proteins. Analysis of knockout mice has demonstrated critical roles of tensin in renal function, muscle regeneration, and cell migration. Therefore, tensin and its downstream signaling molecules may be targets for therapeutic interventions in renal disease, wound healing and cancer.

Actins↗
PubMed2004

Tensin stabilizes integrin adhesive contacts in Drosophila.

We report the functional characterization of the Drosophila ortholog of tensin, a protein implicated in linking integrins to the cytoskeleton and signaling pathways. A tensin null was generated and is viable with wing blisters, a phenotype characteristic of loss of integrin adhesion. In tensin mutants, mechanical abrasion is required during wing expansion to cause wing blisters, suggesting that tensin strengthens integrin adhesion. The localization of tensin requires integrins, talin, and integrin-linked kinase. The N-terminal domain and C-terminal PTB domain of tensin provide essential recruitment signals. The intervening SH2 domain is not localized on its own. We suggest a model where tensin is recruited to sites of integrin adhesion via its PTB and N-terminal domains, localizing the SH2 domain so that it can interact with phosphotyrosine-containing proteins, which stabilize the integrin link to the cytoskeleton.

Animals↗
PubMed1994

Interactions of tensin with actin and identification of its three distinct actin-binding domains.

Tensin, a 200-kD phosphoprotein of focal contacts, contains sequence homologies to Src (SH2 domain), and several actin-binding proteins. These features suggest that tensin may link the cell membrane to the cytoskeleton and respond directly to tyrosine kinase signalling pathways. Here we identify three distinct actin-binding domains within tensin. Recombinant tensin purified after overexpression by a baculovirus system binds to actin filaments with Kd = 0.1 microM, cross-links actin filaments at a molar ratio of 1:10 (tensin/actin), and retards actin assembly by barbed end capping with Kd = 20 nM. Tensin fragments were constructed and expressed as fusion proteins to map domains having these activities. Three regions from tensin interact with actin: two regions composed of amino acids 1 to 263 and 263 to 463, cosediment with F-actin but do not alter the kinetics of actin assembly; a region composed of amino acids 888-989, with sequence homology to insertin, retards actin polymerization. A claw-shaped tensin dimer would have six potential actin-binding sites and could embrace the ends of two actin filaments at focal contacts.

Actin Cytoskeleton↗
PubMedDate not supplied

Treatment of Ras-induced cancers by the F-actin cappers tensin and chaetoglobosin K, in combination with the caspase-1 inhibitor N1445.

UNLABELLED: For transforming normal fibroblasts to malignant cells, oncogenic Ras mutants such as v-Ha-ras require Rho family GTPases (Rho, Rac, and CDC42) that are responsible for controlling actin-cytoskeleton organization. Ras activates Rac through a PI-3 kinase-mediated pathway. Rac causes uncapping of actin filaments (F-actin) at the plus-ends, through phosphatidylinositol 4,5 bisphosphate (PIP2), and eventually induces membrane ruffling. Several distinct F-actin/PIP2-binding proteins, such as gelsolin, which severs and caps the plus-ends of actin filaments, or HS1, which cross-links actin filaments, have been shown to suppress v-Ha-Ras-induced malignant transformation when they are overexpressed. Interestingly, an F-actin cross-linking drug (photosensitizer) called MKT-077 suppresses Ras transformation. Thus, an F-actin capping/severing drug might also have an anticancer potential. PURPOSE: This study was conducted to determine first whether Ras-induced malignant phenotype (anchorage-independent growth) is suppressed by overexpression of the gene encoding a large plus-end F-actin capping protein called tensin and second to test the anti-Ras potential of a unique fungal antibiotic (small compound) called chaetoglobosin K (CK) that also caps the plus-ends of actin filaments. METHODS AND RESULTS: DNA transfection with a retroviral vector carrying the tensin cDNA was used to overexpress tensin in v-Ha-Ras-transformed NIH 3T3 cells. All stable tensin transfectants rarely formed colonies in soft agar, indicating that tensin suppresses the anchorage-independent growth. The anti-Ras action of CK was determined by incubating the Ras-transformants in the presence of CK in soft agar. Two microM CK almost completely inhibited their colony formation, indicating that CK also suppresses the malignant phenotype. However, unlike tensin, CK causes an apoptosis of Ras-transformed NIH 3T3 cells and, less effectively, of normal NIH 3T3 cells, indicating that CK has an F-actin capping-independent side effect(s). CK-induced apoptosis is at least in part caused by CK-induced inhibition of the kinase PKB/AKT. However, a specific ICE/caspase-1 inhibitor called N1445 completely abolished the CK-induced apoptosis by reactivating PKB, but without affecting the CK-induced suppression of Ras transformation. CONCLUSIONS: Like the F-actin cross-linking drug MKT-077, the F-actin capping drug CK may be useful for the treatment of Ras-associated cancers if it is combined with the ICE inhibitor N1445, which abolishes the side effect of CK. Our observations that two distinct F-actin capping molecules (i.e., tensin and CK) suppress Ras-induced malignant phenotype strongly suggest, if not prove, that capping of actin filaments at the plus-ends alone is sufficient to block one of the Ras signaling pathways essential for its oncogenicity. This notion is compatible with the fact that Ras induces the uncapping of actin filaments at the plus-ends through the Rac/PIP2 pathway.

3T3 Cells↗
PubMed2002

Cten, a COOH-terminal tensin-like protein with prostate restricted expression, is down-regulated in prostate cancer.

Tensin is a signaling molecule that binds to actin filaments and localizes to focal adhesions. Recently, we have discovered that tensin represents a new gene family with related members that are expressed in a variety of tissues. In this study, we report the identification and characterization of a new COOH-terminal tensin-like molecule, cten. Human cten cDNA encodes a 715 amino acid sequence containing the Src homology 2 and phosphotyrosine-binding domains that are similar to the COOH termini of tensin molecules. Although cten is shorter and does not have the actin-binding domain found in other tensins, analysis of the genomic structure has suggested that cten is related to the tensin gene family. In addition, cten also localizes to focal adhesions. In contrast to other tensin members, cten expression is restricted to prostate and placenta by Northern blot analysis. Furthermore, examination of cten expression in prostate cancer/cell lines has revealed its down-regulation in tumor samples. Our studies have suggested that during evolution, cten has preserved its role in mediating signal transduction at focal adhesions through the Src homology 2 and phosphotyrosine-binding domains but has lost its function in binding to actin filaments. The evolutionary divergence has produced the first focal adhesion protein specifically expressed in the prostate and the placenta, which may be involved in preventing prostate tumor formation.

Amino Acid Sequence↗
PubMed2000

Structure, production characteristics and fungal antagonism of tensin - a new antifungal cyclic lipopeptide from Pseudomonas fluorescens strain 96.578.

AIM: To study the antagonistic activity by Pseudomonas fluorescens strain 96.578 on the plant pathogenic fungus Rhizoctonia solani. METHODS AND RESULTS: Strain 96.578 produced a new cyclic lipopeptide, tensin. High tensin production per cell was detected in liquid media with glucose, mannitol or glutamate as growth substrate while fructose, sucrose and asparagine supported low production. Tensin production was nearly constant in media with different initial C levels, while low initial N contents reduced production. When applied to sugar beet seeds, strain 96.578 produced tensin during seed germination. When challenged with strain 96.578 or purified tensin, Rhizoctonia solani reduced radial mycelium extension but increased branching and rosette formation. CONCLUSION: The antagonistic activity of strain 96.578 towards Rhizoctonia solani was caused by tensin. SIGNIFICANCE AND IMPACT OF THE STUDY: When coated onto sugar beet seeds, tensin production by strain 96.578 could be of significant importance for inhibition of mycelial growth and seed infection by Rhizoctonia solani.

Anti-Bacterial Agents↗