Treponema: A genus of microorganisms of the order SPIROCHAETALES, many of which are pathogenic and parasitic for man and animals.Treponema pallidum: The causative agent of venereal and non-venereal syphilis as well as yaws.Treponema denticola: A species of bacteria in the family SPIROCHAETACEAE, frequently isolated from periodontal pockets (PERIODONTAL POCKET).Treponemal Infections: Infections with bacteria of the genus TREPONEMA.Syphilis: A contagious venereal disease caused by the spirochete TREPONEMA PALLIDUM.Treponema Immobilization Test: Syphilis serodiagnosis employing as the antigen Treponema pallidum obtained from rabbit syphilis orchitis. Treponemes are kept alive for a few hours in a special medium. When syphilitic serum and complement are added and incubated, the treponemes are immobilized, i.e., stop moving.Yaws: A systemic non-venereal infection of the tropics caused by TREPONEMA PALLIDUM subspecies pertenue.Dysentery: Acute inflammation of the intestine associated with infectious DIARRHEA of various etiologies, generally acquired by eating contaminated food containing TOXINS, BIOLOGICAL derived from BACTERIA or other microorganisms. Dysentery is characterized initially by watery FECES then by bloody mucoid stools. It is often associated with ABDOMINAL PAIN; FEVER; and DEHYDRATION.Syphilis Serodiagnosis: Serologic tests for syphilis.Spirochaetaceae: A family of spiral bacteria of the order SPIROCHAETALES.Spirochaeta: A genus of flexible, spiral rods found in hydrogen sulfide-containing mud, sewage, and polluted water. None of the species properly referred to in this genus are pathogenic.Spirochaetales: An order of slender, flexuous, helically coiled bacteria, with one or more complete turns in the helix.Rabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.Antibodies, Bacterial: Immunoglobulins produced in a response to BACTERIAL ANTIGENS.Digital Dermatitis: Highly contagious infectious dermatitis with lesions near the interdigital spaces usually in cattle. It causes discomfort and often severe lameness (LAMENESS, ANIMAL). Lesions can be either erosive or proliferative and wart-like with papillary growths and hypertrophied hairs. DICHELOBACTER NODOSUS and TREPONEMA are the most commonly associated causative agents for this mixed bacterial infection disease.Syphilis, Congenital: Syphilis acquired in utero and manifested by any of several characteristic tooth (Hutchinson's teeth) or bone malformations and by active mucocutaneous syphilis at birth or shortly thereafter. Ocular and neurologic changes may also occur.Antigens, Bacterial: Substances elaborated by bacteria that have antigenic activity.Syphilis, Cutaneous: Cutaneous lesions arising from infection with Treponema pallidum. In the primary stage, 18-21 days following infection, one or more chancres appear. If untreated, the subsequent stages of the disease appear as syphilids. These eruptions are superficial, nondestructive, exanthematic, transient, macular roseolas that may later be maculopapular or papular polymorphous or scaly, pustular, pigmented eruptions.(Arnold, Odom, and James, Andrew's Diseases of the Skin, 8th ed, p409)Chancre: The primary sore of syphilis, a painless indurated, eroded papule, occurring at the site of entry of the infection.Gingivitis, Necrotizing Ulcerative: An acute or chronic GINGIVITIS characterized by redness and swelling, NECROSIS extending from the interdental papillae along the gingival margins, PAIN; HEMORRHAGE, necrotic odor, and often a pseudomembrane. The condition may extend to the ORAL MUCOSA; TONGUE; PALATE; or PHARYNX. The etiology is somewhat unclear, but may involve a complex of FUSOBACTERIUM NUCLEATUM along with spirochetes BORRELIA or TREPONEMA.Neurosyphilis: Infections of the central nervous system caused by TREPONEMA PALLIDUM which present with a variety of clinical syndromes. The initial phase of infection usually causes a mild or asymptomatic meningeal reaction. The meningovascular form may present acutely as BRAIN INFARCTION. The infection may also remain subclinical for several years. Late syndromes include general paresis; TABES DORSALIS; meningeal syphilis; syphilitic OPTIC ATROPHY; and spinal syphilis. General paresis is characterized by progressive DEMENTIA; DYSARTHRIA; TREMOR; MYOCLONUS; SEIZURES; and Argyll-Robertson pupils. (Adams et al., Principles of Neurology, 6th ed, pp722-8)Dermatitis: Any inflammation of the skin.Periodontal Diseases: Pathological processes involving the PERIODONTIUM including the gum (GINGIVA), the alveolar bone (ALVEOLAR PROCESS), the DENTAL CEMENTUM, and the PERIODONTAL LIGAMENT.Bacterial Proteins: Proteins found in any species of bacterium.Mouth: The oval-shaped oral cavity located at the apex of the digestive tract and consisting of two parts: the vestibule and the oral cavity proper.Periodontitis: Inflammation and loss of connective tissues supporting or surrounding the teeth. This may involve any part of the PERIODONTIUM. Periodontitis is currently classified by disease progression (CHRONIC PERIODONTITIS; AGGRESSIVE PERIODONTITIS) instead of age of onset. (From 1999 International Workshop for a Classification of Periodontal Diseases and Conditions, American Academy of Periodontology)Hemagglutination Tests: Sensitive tests to measure certain antigens, antibodies, or viruses, using their ability to agglutinate certain erythrocytes. (From Stedman, 26th ed)Dental Plaque: A film that attaches to teeth, often causing DENTAL CARIES and GINGIVITIS. It is composed of MUCINS, secreted from salivary glands, and microorganisms.Brachyspira hyodysenteriae: A species of anaerobic, spiral bacteria that was formerly classified as Serpulina hyodysenteriae and Treponema hyodysenteriae (and for a short while, Serpula hyodysenteriae). This organism is the agent of swine dysentery.DNA, Bacterial: Deoxyribonucleic acid that makes up the genetic material of bacteria.Gingiva: Oral tissue surrounding and attached to TEETH.Periodontal Pocket: An abnormal extension of a gingival sulcus accompanied by the apical migration of the epithelial attachment and bone resorption.Penicillin G Benzathine: Semisynthetic antibiotic prepared by combining the sodium salt of penicillin G with N,N'-dibenzylethylenediamine.Foot Diseases: Anatomical and functional disorders affecting the foot.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Flagella: A whiplike motility appendage present on the surface cells. Prokaryote flagella are composed of a protein called FLAGELLIN. Bacteria can have a single flagellum, a tuft at one pole, or multiple flagella covering the entire surface. In eukaryotes, flagella are threadlike protoplasmic extensions used to propel flagellates and sperm. Flagella have the same basic structure as CILIA but are longer in proportion to the cell bearing them and present in much smaller numbers. (From King & Stansfield, A Dictionary of Genetics, 4th ed)Genitalia: The external and internal organs related to reproduction.Syphilis, LatentSwine Diseases: Diseases of domestic swine and of the wild boar of the genus Sus.Bacterial Outer Membrane Proteins: Proteins isolated from the outer membrane of Gram-negative bacteria.RNA, Ribosomal, 16S: Constituent of 30S subunit prokaryotic ribosomes containing 1600 nucleotides and 21 proteins. 16S rRNA is involved in initiation of polypeptide synthesis.Pinta: An infectious disease of the skin caused by Treponema carateum that occurs only in the western hemisphere. Age of onset is between 10 and 20 years of age. This condition is characterized by marked changes in the skin color and is believed to be transmitted by direct person-to-person contact.Encyclopedias as Topic: Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)Dictionaries, MedicalDictionaries as Topic: Lists of words, usually in alphabetical order, giving information about form, pronunciation, etymology, grammar, and meaning.Dictionaries, ChemicalCrowdsourcing: Social media model for enabling public involvement and recruitment in participation. Use of social media to collect feedback and recruit volunteer subjects.Terminology as Topic: The terms, expressions, designations, or symbols used in a particular science, discipline, or specialized subject area.Antibodies: Immunoglobulin molecules having a specific amino acid sequence by virtue of which they interact only with the ANTIGEN (or a very similar shape) that induced their synthesis in cells of the lymphoid series (especially PLASMA CELLS).Antibody Specificity: The property of antibodies which enables them to react with some ANTIGENIC DETERMINANTS and not with others. Specificity is dependent on chemical composition, physical forces, and molecular structure at the binding site.Antibodies, Viral: Immunoglobulins produced in response to VIRAL ANTIGENS.

Activation of murine macrophages by lipoprotein and lipooligosaccharide of Treponema denticola. (1/399)

We have recently demonstrated that the periodontopathogenic oral spirochete Treponema denticola possesses membrane-associated lipoproteins in addition to lipooligosaccharide (LOS). The aim of the present study was to test the potential of these oral spirochetal components to induce the production of inflammatory mediators by human macrophages, which in turn may stimulate tissue breakdown as observed in periodontal diseases. An enriched lipoprotein fraction (dLPP) from T. denticola ATCC 35404 obtained upon extraction of the treponemes with Triton X-114 was found to stimulate the production of nitric oxide (NO), tumor necrosis factor alpha (TNF-alpha), and interleukin-1 (IL-1) by mouse macrophages in a dose-dependent manner. Induction of NO by dLPP was at 25% of the levels obtained by Salmonella typhosa lipopolysaccharide (LPS) at similar concentrations, while IL-1 was produced at similar levels by both inducers. dLPP-mediated macrophage activation was unaffected by amounts of polymyxin B that neutralized the induction produced by S. typhosa LPS. dLPP also induced NO and TNF-alpha secretion from macrophages isolated from endotoxin-unresponsive C3H/HeJ mice to an extent similar to the stimulation produced in endotoxin-responsive mice. Purified T. denticola LOS also produced a concentration-dependent activation of NO and TNF-alpha in LPS-responsive and -nonresponsive mouse macrophages. However, macrophage activation by LOS was inhibited by polymyxin B. These results suggest that T. denticola lipoproteins and LOS may play a role in the inflammatory processes that characterize periodontal diseases.  (+info)

Treponema denticola outer membrane enhances the phagocytosis of collagen-coated beads by gingival fibroblasts. (2/399)

Human gingival fibroblasts (HGFs) degrade collagen fibrils in physiological processes by phagocytosis. Since Treponema denticola outer membrane (OM) extract perturbs actin filaments, important structures in phagocytosis, we determined whether the OM affects collagen phagocytosis in vitro by HGFs. Phagocytosis was measured by flow cytometric assessment of internalized collagen-coated fluorescent latex beads. Confluent HGFs pretreated with T. denticola ATCC 35405 OM exhibited an increase in the percentage of collagen phagocytic cells (phagocytosis index [PI]) and in the number of beads per phagocytosing cell (phagocytic capacity [PC]) compared with untreated controls. The enhancement was swift (within 15 min) and was still evident after 1 day. PI and PC of HGFs for bovine serum albumin (BSA)-coated beads were also increased, indicating a global increase in phagocytic processes. These results contrasted those for control OM from Veillonella atypica ATCC 17744, which decreased phagocytosis. The T. denticola OM-induced increase in bead uptake was eliminated by heating the OM and by depolymerization of actin filaments by cytochalasin D treatment of HGFs. Fluid-phase accumulation of lucifer yellow was enhanced in a saturable, concentration-dependent, transient manner by the T. denticola OM. Our findings were not due to HGF detachment or cytotoxicity in response to the T. denticola OM treatment since the HGFs exhibited minimal detachment from the substratum; they did not take up propidium iodide; and there was no change in their size, granularity, or content of sub-G1 DNA. We conclude that a heat-sensitive component(s) in T. denticola OM extract stimulates collagen phagocytosis and other endocytic processes such as nonspecific phagocytosis and pinocytosis by HGFs.  (+info)

Treponema brennaborense sp. nov., a novel spirochaete isolated from a dairy cow suffering from digital dermatitis. (3/399)

A novel Treponema species was isolated from an ulcerative lesion of a cow suffering from digital dermatitis (DD), a disease which causes painful ulcerations along the coronary band. Among other anaerobic bacteria, high numbers of spirochaetes have been regularly found in DD lesions. Here data are presented of a spirochaete isolated from a DD ulcer. By chemotaxonomy, protein analysis and comparative 16S rDNA sequence analysis this isolate was classified as a treponeme that differed from all Treponema species described previously. The only isolate, DD5/3T, for which the name Treponema brennaborense is proposed, is designated the type strain of the novel species. The strain is a small, highly motile spirochaete that has two periplasmic flagella, one flagellum being attached at each cell pole. Strain DD5/3T exhibits alpha-glucosidase and N-acetyl-beta-glucosaminidase activity and growth is inhibited by rabbit serum. T. brennaborense was phylogenetically most closely related (89.5% 16S rRNA similarity) to Treponema maltophilum, an oral spirochaete isolated from a periodontitis patient.  (+info)

Cystalysin, a 46-kDa L-cysteine desulfhydrase from Treponema denticola: biochemical and biophysical characterization. (4/399)

A 46-kDa hemolytic protein referred to as cystalysin, from Treponema denticola ATCC 35404, was characterized and overexpressed in Escherichia coli LC-67. Cystalysin lysed erythrocytes, hemoxidized hemoglobin to sulfhemoglobin and methemoglobin, and removed the sulfhydryl and amino group from selected S-containing compounds (e.g., cysteine) producing H2S, NH3, and pyruvate. With L-cysteine as substrate, cystalysin obeys Michaelis-Menten kinetics. Cystathionine and s-aminoethyl-L-cysteine were also substrates. Several of the small alpha amino acids were found to be competitive inhibitors of cystalysin. The enzymatic activity was increased by beta-mercaptoethanol and was not inhibited by the proteinase inhibitor TLCK (N alpha-p-tosyl-L-lysine chloromethyl ketone), pronase, or proteinase K, suggesting the functional site was physically protected or located in a small fragment of the polypeptide. We hypothesize that cystalysin is a pyridoxal-5-phosphate-containing enzyme with the activity of an alphaC-N and betaC-S lyase (cystathionase). Since high amounts of H2S have been reported in deep periodontal pockets, this metabolic enzyme from T. denticola may also function in vivo as an important virulence molecule.  (+info)

Glyceraldehyde-3-phosphate dehydrogenase gene diversity in eubacteria and eukaryotes: evidence for intra- and inter-kingdom gene transfer. (5/399)

Cyanobacteria contain up to three highly divergent glyceraldehyde-3-phosphate dehydrogenase (GAPDH) genes: gap1, gap2, and gap3. Genes gap1 and gap2 are closely related at the sequence level to the nuclear genes encoding cytosolic and chloroplast GAPDH of higher plants and have recently been shown to play distinct key roles in catabolic and anabolic carbon flow, respectively, of the unicellular cyanobacterium Synechocystis sp. PCC6803. In the present study, sequences of 10 GAPDH genes distributed across the cyanobacteria Prochloron didemni, Gloeobacter violaceus PCC7421, and Synechococcus PCC7942 and the alpha-proteobacterium Paracoccus denitrificans and the beta-proteobacterium Ralstonia solanacearum were determined. Prochloron didemni possesses homologs to the gap2 and gap3 genes from Anabaena, Gloeobacter harbors gap1 and gap2 homologs, and Synechococcus possesses gap1, gap2, and gap3. Paracoccus harbors two highly divergent gap genes that are related to gap3, and Ralstonia possesses a homolog of the gap1 gene. Phylogenetic analyses of these sequences in the context of other eubacterial and eukaryotic GAPDH genes reveal that divergence across eubacterial gap1, and gap2, and gap3 genes is greater than that between eubacterial gap1 and eukaroytic glycolytic GapC or between eubacterial gap2 and eukaryotic Calvin cycle GapAB. These data strongly support previous analyses which suggested that eukaryotes acquired their nuclear genes for GapC and GapAB via endosymbiotic gene transfer from the antecedents of mitochondria and chloroplasts, and extend the known range of sequence diversity of the antecedent eubacterial genes. Analyses of available GAPDH sequences from other eubacterial sources indicate that the glycosomal gap gene from trypanosomes (cytosolic in Euglena) and the gap gene from the spirochete Treponema pallidum are each other's closest relatives. This specific relationship can therefore not reflect organismal evolution but must be the result of an interkingdom gene transfer, the direction of which cannot be determined with certainty at present. Contrary to this, the origin of the cytosolic Gap gene from trypanosomes can now be clearly defined as gamma-proteobacterial, since the newly established Ralstonia sequence (beta-proteobacteria) branches basally to the gamma-proteobacterial/trypanosomal assemblage.  (+info)

Environmental modulation of oral treponeme virulence in a murine model. (6/399)

This investigation examined the effects of environmental alteration on the virulence of the oral treponemes Treponema denticola and Treponema pectinovorum. The environmental effects were assessed by using a model of localized inflammatory abscesses in mice. In vitro growth of T. denticola and T. pectinovorum as a function of modification of the cysteine concentration significantly enhanced abscess formation and size. In contrast, growth of T. denticola or T. pectinovorum under iron-limiting conditions (e.g., dipyridyl chelation) had no effect on abscess induction in comparison to that when the strains were grown under normal iron conditions. In vivo modulation of the microenvironment at the focus of infection with Cytodex beads demonstrated that increasing the local inflammation had no effect on lesion induction or size. In vivo studies involved the determination of the effects of increased systemic iron availability (e.g., iron dextran or phenylhydrazine) on the induction, kinetics, and size of lesions. T. denticola induced significantly larger lesions in mice with iron pretreatment and demonstrated systemic manifestations of the infectious challenge and an accompanying spreading lesion with phenylhydrazine pretreatment (e.g., increases in circulating free hemoglobin). In contrast, T. pectinovorum virulence was minimally affected by this in vivo treatment to increase iron availability. T. denticola virulence, as evaluated by lesion size, was increased additively by in vivo iron availability, and cysteine modified growth of the microorganism. Additionally, galactosamine sensitized mice to a lethal outcome following infection with both T. denticola and T. pectinovorum, suggesting an endotoxin-like activity in these treponemes. These findings demonstrated the ability to modify the virulence capacity of T. denticola and T. pectinovorum by environmental conditions which can be evaluated by using in vivo murine models.  (+info)

Insertional inactivation of Treponema denticola tap1 results in a nonmotile mutant with elongated flagellar hooks. (7/399)

The treponemal fla operon is comprised of numerous motility-related genes; however, the initial gene of this operon, tap1, has no known function. A recently developed system to generate specific mutants in Treponema denticola was utilized to determine if Tap1 was essential for motility. T. denticola tap1 and flanking DNA were identified, cloned, and sequenced, and a suicide plasmid that contained tap1 interrupted with an erythromycin resistance cassette (ermF and ermAM) was constructed. Because of potential polar effects from this cassette, a second plasmid that contained tap1 interrupted with a modified erythromycin resistance cassette that lacked the putative ermF transcription terminator was constructed. Electroporation-mediated allelic exchange incorporated the interrupted tap1 genes into the T. denticola chromosome, creating Tap1-deficient mutants. Reverse transcriptase PCR revealed that the erythromycin resistance cassette within tap1 did not terminate fla operon transcription in either mutant. Moreover, the phenotypes of the two mutants were indistinguishable. These mutants lacked motion in liquid culture, were unable to spread on agar plates, and lacked flagellar filaments as determined by electron microscopy. Immunoblots revealed a marked reduction in detectable FlaB flagellar filament protein compared to that of wild type; however, flaB RNA was easily detectable, and transcription levels did not appear to be altered. The basis for the lack of filament protein expression is unknown. Immunoblotting also showed that the flagellar hook protein (FlgE) was synthesized in the Tap1-deficient mutant; however, electron microscopy revealed that the mutant possessed unusual elongated hooks of variable lengths. We propose that treponemal Tap1 is analogous to FliK, which is involved in monitoring the flagellar hook length of Salmonella typhimurium.  (+info)

Development of a system for expressing heterologous genes in the oral spirochete Treponema denticola and its use in expression of the Treponema pallidum flaA gene. (8/399)

The present communication describes the construction of a new Escherichia coli-Treponema denticola shuttle vector based on the naturally occurring spirochete plasmid pTS1 and the expression of the heterologous T. pallidum flaA gene from the plasmid in T. denticola. This new shuttle vector system should prove useful in characterizing virulence factors from unculturable pathogenic spirochetes.  (+info)

  • 1984 Treponema stenostreptum (Zuelzer 1912) Abt, Göker & Klenk 2013 Treponema succinifaciens Cwyk and Canale-Parola 1981 Treponema zuelzerae (ex Veldkamp 1960) Canale-Parola 1980 emend. (wikipedia.org)
  • Moreover, through genome reconstruction (2.2-2.5 MB, coverage depth × 26-513) and functional potential characterization, we discover these Treponema are diverse, fall outside of pathogenic clades and are similar to Treponema succinifaciens, a known carbohydrate metabolizer in swine. (blogspot.com)
  • Penicillin-binding proteins of 180, 89, 80, 68, 61, 41, and 38 kilodaltons were identified in Treponema pallidum (Nichols) by their covalent binding of [35S]benzylpenicillin. (asm.org)
  • K vyhledání sekvenčně divergentních oblastí genomu mezi kmeny Nichols a SS14 bylo využito hybridizace genomové DNA k čipu, který obsahoval oligonukleotidy pokrývající chromozomální sekvenci Treponema pallidum ssp. (theses.cz)
  • The lack of in vitro culture techniques and genetic systems for Treponema pallidum has made it extremely difficult to identify virulence or regulatory factors involved in the pathogenesis of syphilis. (pnas.org)
  • The fundamental reason for this controversy is the inability to culture Treponema pallidum in vitro on routine culture media or in tissue culture. (antimicrobe.org)
  • molecular typing}, language = {eng}, location = {Neuveden}, pages = {495-495}, publisher = {European Society of Clinical Microbiology and Infectious Diseases}, title = {Sequencing and molecular typing of hypervariable loci in the Treponema pallidum genomes: characterizations of type strains and clinical isolates. (muni.cz)
  • Major breakthroughs include sequencing of Treponema genomes and the development of modern molecular methods. (caister.com)
  • 1. Immune sera produced in rabbits by treatment with our Culture Strain A of Treponema pallidum agglutinated not only the homologous strain, but also the Noguchi strains, and indicate a close group relationship of other non-pathogenic treponemata. (rupress.org)
  • At our institution, like many others, the laboratory diagnosis of syphilis is achieved by first screening serum with a nontreponemal test and then confirming positive results with a treponema-specific test. (asm.org)
  • The objective of the present study was to compare the accuracy of the CAPTIA Syphilis-G EIA to that of a treponema-specific test currently used in our laboratory, the FTA-ABS test (Zeus Scientific, Inc., Raritan, N.J.). Eighty-nine serum samples submitted to our laboratory for syphilis testing were evaluated by both of these test methods. (asm.org)
  • Die Treponema ViraChip ® IgG und IgM sind Protein-Microarrays zum qualitativen Nachweis von IgG und IgM Antikörpern gegen Treponema-spezifische Antigene in humanem Serum. (viramed.de)
  • The purpose of this study was to evaluate diagnostic performances of LIAISON Treponema Screen (DiaSorin, Saluggia, Italy), a new automated chemiluminescence immunoassay (CLIA), in comparison with performances of EIA, WB, and TPHA. (asm.org)
  • Macrolide-resistant strains of Treponema pallidum are now prevalent in several developed countries. (asm.org)
  • However, application of specific epithets to the strains isolated ( Treponema strains ZAS-1, ZAS-2, and ZAS-9) was postponed pending a more complete characterization of their phenotypic properties. (asm.org)
  • The isolates were simply referred to as Treponema strains ZAS-1, ZAS-2, and ZAS-9, with assignment of specific epithets postponed until a more detailed characterization of the strains could be performed. (asm.org)
  • IMPORTANCE Despite recent progress characterizing outer membrane proteins (OMPs) of Treponema pallidum, little is known about how their surface-exposed, β-barrel-forming domains vary among strains circulating within high-risk populations. (diva-portal.org)
  • 2006 ?Treponema refringens ♠ (Schaudinn and Hofmann 1905) Castellani and Chalmers ?Treponema vincentii ♠ Smibert 1984 ?Treponema zioleckii ♠ Piknova et al. (wikipedia.org)
  • Treponema pallidum was discovered in 1905 by the German bacteriologist Fritz Schaudinn (1871-1906) who named it, putting together the Greek trepo (I turn) and nema ( thread ) with the Latin pallida (pale) to make a pale turning thread. (academic.ru)