Symbolic innovation at the onset of the Upper Paleolithic in Eurasia shown by the personal ornaments from Tolbor-21 (Mongolia).

Figurative depictions in art first occur ca. 50,000 years ago in Europe, Africa, and Southeast Asia. Considered by most as an advanced form of symbolic behavior, they are restricted to our species. Here, we report a piece of ornament interpreted as a phallus-like representation. It was found in a 42,000 ca.-year-old Upper Paleolithic archaeological layer at the open-air archaeological site of Tolbor-21, in Mongolia. Mineralogical, microscopic, and rugosimetric analyses points toward the allochthonous origin of the pendant and a complex functional history. Three-dimensional phallic pendants are unknown in the Paleolithic record, and this discovery predates the earliest known sexed anthropomorphic representation. It attests that hunter-gatherer communities used sex anatomical attributes as symbols at a very early stage of their dispersal in the region. The pendant was produced during a period that overlaps with age estimates for early introgression events between Homo sapiens and Denisovans, and in a region where such encounters are plausible.

Clinical characteristics and factors associated with COVID-19-related mortality and hospital admission during the first two epidemic waves in 5 rural provinces in Indonesia: A retrospective cohort study.

BACKGROUND: Data on coronavirus disease 2019 (COVID-19) clinical characteristics and severity from resource-limited settings are limited. This study examined clinical characteristics and factors associated with COVID-19 mortality and hospitalisation in rural settings of Indonesia, from 1 January to 31 July, 2021. METHODS: This retrospective cohort included individuals diagnosed with COVID-19 based on polymerase chain reaction or rapid antigen diagnostic test, from five rural provinces in Indonesia. We extracted demographic and clinical data, including hospitalisation and mortality from a new piloted COVID-19 information system named Sistem Informasi Surveilans Epidemiologi (SISUGI). We used mixed-effect logistic regression to examine factors associated with COVID-19-related mortality and hospitalisation. RESULTS: Of 6,583 confirmed cases, 205 (3.1%) died and 1,727 (26.2%) were hospitalised. The median age was 37 years (Interquartile range 26-51), with 825 (12.6%) under 20 years, and 3,371 (51.2%) females. Most cases were symptomatic (4,533; 68.9%); 319 (4.9%) had a clinical diagnosis of pneumonia and 945 (14.3%) presented with at least one pre-existing comorbidity. Age-specific mortality rates were 0.9% (2/215) for 0-4 years; 0% (0/112) for 5-9 years; 0% (1/498) for 10-19 years; 0.8% (11/1,385) for 20-29 years; 0.9% (12/1,382) for 30-39 years; 2.1% (23/1,095) for 40-49 years; 5.4% (57/1,064) for 50-59 years; 10.8% (62/576) for 60-69 years; 15.9% (37/232) for ≥70 years. Older age, pre-existing diabetes, chronic kidney disease, liver diseases, malignancy, and pneumonia were associated with higher risk of mortality and hospitalisation. Pre-existing hypertension, cardiac diseases, COPD, and immunocompromised condition were associated with risk of hospitalisation but not with mortality. There was no association between province-level density of healthcare workers with mortality and hospitalisation. CONCLUSION: The risk of COVID-19-related mortality and hospitalisation was associated with higher age, pre-existing chronic comorbidities, and clinical pneumonia. The findings highlight the need for prioritising enhanced context-specific public health action to reduce mortality and hospitalisation risk among older and comorbid rural populations.

Paleolithic occupation of arid Central Asia in the Middle Pleistocene.

Central Asia is positioned at a crossroads linking several zones important to hominin dispersal during the Middle Pleistocene. However, the scarcity of stratified and dated archaeological material and paleoclimate records makes it difficult to understand dispersal and occupation dynamics during this time period, especially in arid zones. Here we compile and analyze paleoclimatic and archaeological data from Pleistocene Central Asia, including examination of a new layer-counted speleothem-based multiproxy record of hydrological changes in southern Uzbekistan at the end of MIS 11. Our findings indicate that Lower Palaeolithic sites in the steppe, semi-arid, and desert zones of Central Asia may have served as key areas for the dispersal of hominins into Eurasia during the Middle Pleistocene. In agreement with previous studies, we find that bifaces occur across these zones at higher latitudes and in lower altitudes relative to the other Paleolithic assemblages. We argue that arid Central Asia would have been intermittently habitable during the Middle Pleistocene when long warm interglacial phases coincided with periods when the Caspian Sea was experiencing consistently high water levels, resulting in greater moisture availability and more temperate conditions in otherwise arid regions. During periodic intervals in the Middle Pleistocene, the local environment of arid Central Asia was likely a favorable habitat for paleolithic hominins and was frequented by Lower Paleolithic toolmakers producing bifaces.

Clinical characteristics and factors associated with COVID-19-related mortality and hospital admission in 5 rural provinces in Indonesia: a retrospective cohort study

BackgroundData on COVID-19 clinical characteristics and severity from resource-limited settings are limited. This study examined clinical characteristics and factors associated with COVID-19 mortality and hospitalisation in rural settings of Indonesia, from 1 January to 31 July, 2021. MethodsThis retrospective cohort included individuals diagnosed with COVID-19 based on polymerase chain reaction or rapid antigen diagnostic test, from Lampung, Gorontalo, Central Sulawesi, Southeast Sulawesi, and East Nusa Tenggara Provinces. We extracted demographic and clinical data, including hospitalisation and mortality from COVID-19 surveillance records. We used mixed-effect logistic regression to examine factors associated with COVID-19-related mortality and hospitalisation. ResultsOf 6,583 confirmed cases, 205 (3.1%) died, and 1,727 (26%) were hospitalised. The median age was 37 years (IQR 26-52), with 825 (12{middle dot}53%) under 20 years, and 3,371 (51.21%) females. 4,533 (68.86%) cases were symptomatic, 319 (4.85%) had a clinical diagnosis of pneumonia, and 945 (14.36%) with at least one pre-existing comorbidity. The mortality and hospitalisation rate ranged from 2.0% and 13.4% in East Nusa Tenggara to 4.3% and 36{middle dot}1% in Lampung. Age-specific mortality rates were 0.9% (2/340) for 0-4 years; 0% (0/112) for 5-9 years; 0.2% (1/498) for 10-19 years; 0.8% (11/1,385) for 20-29 years; 0.9% (12/1,382) for 30-39 years; 2% (23/1,095) for 40-49 years; 5% (57/1,064) for 50-59 years; 11% (62/576) for 60-69 years; 16% (37/232) for [≥]70 years. Older age, pre-existing diabetes, liver diseases, malignancy, and pneumonia were associated with higher risk of mortality and hospitalisation. Pre-existing hypertension, cardiac diseases, chronic kidney disease, COPD, and immunocompromised condition were associated with risk of hospitalisation but not with mortality. ConclusionClinical characteristics and risk factors of severe COVID-19 outcomes in rural provinces were broadly similar to those in urban settings. The risk of COVID-19-related mortality and hospitalisation was associated with higher age, pre-existing chronic comorbidities, and clinical presentation of pneumonia.

The effect of separation of blocks on the crystallization kinetics and phase composition of poly(butylene adipate) in multi-block thermoplastic polyurethanes.

The influence of the hard segment nature on the crystallization kinetics of multi-block thermoplastic polyurethanes containing poly(butylene adipate) (PBA) as a soft segment was investigated. Using a combination of FTIR spectroscopy, time-domain 1H nuclear magnetic resonance (TD-NMR), differential scanning calorimetry (DSC), fast-scanning calorimetry (FSC) and wide-angle X-ray diffraction (WAXS), it was shown that aliphatic, cycloaliphatic and aromatic diisocyanates affect the phase separation efficiency of soft and hard segments. The best phase separation efficiency was observed for a sample containing aliphatic diisocyanate due to the development of a hydrogen bond network. The thermal history, phase separation and the degree of ordering of the polyurethane determine the polymorphic behavior of melt-crystallized PBA. The formation of a partially-ordered mesophase of linear aliphatic polyurethane leads to an increase in the crystallization rate of PBA at room temperature and the formation of thermodynamically stable α-crystals. The presence of bulk cycloaliphatic and aromatic diol-urethane fragments prevents the phase separation of PBA, which crystallizes after slow cooling in a mixture of α- and ß-crystalline forms. The new nanocalorimetry technique allows the identification of a direct correlation between the phase separation and crystallization kinetics of the melt-crystallized PBA in a wide range of cooling rates - from 2 to 30 000 K s-1. Particularly, ultra-fast cooling suppresses the nucleation of the ß-phase of PBA resulting in slow crystallization of only α-modification at room temperature. The role of the polyurethane mesophase in the crystallization of the soft segment was discussed for the first time.

Can exposure to arguments pro and contra extraversion affect self-reports of the trait and the attitude toward it?

OBJECTIVE: Changeability of personality over short-term intervals has increasingly become a focus of research. However, the role played by argumentation interventions in short-term variations has scarcely been examined. METHODS: In two experiments (N = 363 and 320), we investigated how processing positive and negative argumentation regarding extraversion (Study 1: watching a lecture; Study 2: elaborating self-invented arguments) affects self-reports on this trait and attitude toward it. The experiments included three waves of measurements with argument manipulation (in favor of or against extraversion) immediately prior to Time 2 (Study 2 also included a control group). RESULTS: Mean-level changes in extraversion across time moments, measured with the longitudinal confirmatory factor analysis, were consistently negligible. Conversely, there were some indications that argumentation about extraversion could have immediate short-term effects on attitudes toward this trait. The random-intercept cross-lagged model showed that rank-order consistency stemmed from a trait-like intercept, which was particularly large for trait extraversion compared with the attitude. The autoregressive and cross-lagged effects of residual within-person variation were consistently small and mostly nonsignificant. CONCLUSION: Our findings suggest that extraversion and the attitude toward it maintained their temporal continuity within 3 months, even under a single exposure to arguments pro and contra this trait.

Measurement Invariance and Sex and Age Differences of the Big Five Inventory-2: Evidence From the Russian Version.

The Big Five Inventory-2 (BFI-2) is a recently published 60-item questionnaire that measures personality traits within the five-factor model framework. An important aspect of the BFI-2 is that it measures the traits at both the domain and facet levels and also controls acquiescence bias via the balanced number of true- and false-keyed items across the domains and facets. The current research evaluates factorial measurement invariance of a Russian version of the BFI-2 across sex and age within samples of 1,024 university students (Study 1) and 1,029 Internet users (Study 2). Across these samples, men scored lower on the domains of negative emotionality and agreeableness and slightly higher on extraversion. Sex differences were also obtained on various facets. In the Internet sample, age correlated modestly with several Big Five domains in accordance with the well-documented maturity principle. The newly developed Russian version of BFI-2 showed good reliability and validity across both samples. Moreover, random intercept exploratory factor analyses showed that the BFI-2 displayed a hierarchical five-domain-15-facet structure that demonstrated strict measurement invariance across sex and age.

The Northern Route for Human dispersal in Central and Northeast Asia: New evidence from the site of Tolbor-16, Mongolia.

The fossil record suggests that at least two major human dispersals occurred across the Eurasian steppe during the Late Pleistocene. Neanderthals and Modern Humans moved eastward into Central Asia, a region intermittently occupied by the enigmatic Denisovans. Genetic data indicates that the Denisovans interbred with Neanderthals near the Altai Mountains (South Siberia) but where and when they met H. sapiens is yet to be determined. Here we present archaeological evidence that document the timing and environmental context of a third long-distance population movement in Central Asia, during a temperate climatic event around 45,000 years ago. The early occurrence of the Initial Upper Palaeolithic, a techno-complex whose sudden appearance coincides with the first occurrence of H. sapiens in the Eurasian steppes, establishes an essential archaeological link between the Siberian Altai and Northwestern China . Such connection between regions provides empirical ground to discuss contacts between local and exogenous populations in Central and Northeast Asia during the Late Pleistocene.

Dual cellular localization of the Leishmania amazonensis Rbp38 (LaRbp38) explains its affinity for telomeric and mitochondrial DNA.

Rbp38 is a protein exclusively found in trypanosomatid parasites, including Leishmania amazonensis, the etiologic agent of tegumentar leishmaniasis in the Americas. The protein was first described as a Leishmania tarentolae mitochondrial RNA binding protein. Later, it was shown that the trypanosomes Rbp38 orthologues were exclusively found in the mitochondria and involved in the stabilization and replication of kinetoplast DNA (kDNA). In contrast, L. amazonensis Rbp38 (LaRbp38), co-purifies with telomerase activity and interacts not only with kDNA but also with telomeric DNA, although shares with its counterparts high sequence identity and a putative N-terminal mitochondrial targeting signal (MTS). To understand how LaRbp38 interacts both with nuclear and kDNA, we have first investigated its subcellular localization. Using hydroxy-urea synchronized L. amazonensis promastigotes we could show that LaRbp38 shuttles from mitochondria to the nucleus at late S and G2 phases. Further, we identified a non-classical nuclear localization signal (NLS) at LaRbp38 C-terminal that binds with importin alpha, a protein involved in the nuclear transport of several proteins. Also, we obtained LaRbp38 truncated forms among which, some of them also showed an affinity for both telomeric DNA and kDNA. Analysis of these truncated forms showed that LaRbp38 DNA-binding region is located between amino acid residues 95-235. Together, our findings strongly suggest that LaRbp38 is multifunctional with dual subcellular localization.

Dual cellular localization of the Leishmania amazonensis Rbp38 (LaRbp38) explains its affinity for telomeric and mitochondrial DNA

Rbp38 is a protein exclusively found in trypanosomatid parasites, including Leishmania amazonensis, the etiologic agent of tegumentar leishmaniasis in the Americas. The protein was first described as a Leishmania tarentolae mitochondrial RNA binding protein. Later, it was shown that the trypanosomes Rbp38 orthologues were exclusively found in the mitochondria and involved in the stabilization and replication of kinetoplast DNA (kDNA). In contrast, L. amazonensis Rbp38 (LaRbp38), co-purifies with telomerase activity and interacts not only with kDNA but also with telomeric DNA, although shares with its counterparts high sequence identity and a putative N-terminal mitochondrial targeting signal (MTS). To understand how LaRbp38 interacts both with nuclear and kDNA, we have first investigated its subcellular localization. Using hydroxy-urea synchronized L. amazonensis promastigotes we could show that LaRbp38 shuttles from mitochondria to the nucleus at late S and G2 phases. Further, we identified a non-classical nuclear localization signal (NLS) at LaRbp38?C-terminal that binds with importin alpha, a protein involved in the nuclear transport of several proteins. Also, we obtained LaRbp38 truncated forms among which, some of them also showed an affinity for both telomeric DNA and kDNA. Analysis of these truncated forms showed that LaRbp38 DNA-binding region is located between amino acid residues 95–235. Together, our findings strongly suggest that LaRbp38 is multifunctional with dual subcellular localization.

Dual cellular localization of the Leishmania amazonensis Rbp38 (LaRbp38) explains its affinity for telomeric and mitochondrial DNA

Rbp38 is a protein exclusively found in trypanosomatid parasites, including Leishmania amazonensis, the etiologic agent of tegumentar leishmaniasis in the Americas. The protein was first described as a Leishmania tarentolae mitochondrial RNA binding protein. Later, it was shown that the trypanosomes Rbp38 orthologues were exclusively found in the mitochondria and involved in the stabilization and replication of kinetoplast DNA (kDNA). In contrast, L. amazonensis Rbp38 (LaRbp38), co-purifies with telomerase activity and interacts not only with kDNA but also with telomeric DNA, although shares with its counterparts high sequence identity and a putative N-terminal mitochondrial targeting signal (MTS). To understand how LaRbp38 interacts both with nuclear and kDNA, we have first investigated its subcellular localization. Using hydroxy-urea synchronized L. amazonensis promastigotes we could show that LaRbp38 shuttles from mitochondria to the nucleus at late S and G2 phases. Further, we identified a non-classical nuclear localization signal (NLS) at LaRbp38?C-terminal that binds with importin alpha, a protein involved in the nuclear transport of several proteins. Also, we obtained LaRbp38 truncated forms among which, some of them also showed an affinity for both telomeric DNA and kDNA. Analysis of these truncated forms showed that LaRbp38 DNA-binding region is located between amino acid residues 95–235. Together, our findings strongly suggest that LaRbp38 is multifunctional with dual subcellular localization.

Strong and frequent T-cell responses to the minor allergen Phl p 12 in Spanish patients IgE-sensitized to Profilins.

BACKGROUND: Profilins are dominant pan-allergens known to cause cross-sensitization, leading to clinical symptoms such as pollen-food syndrome. This study aimed to determine the T-cell response to Phl p 12 in profilin-sensitized patients, by measuring the prevalence, strength and cross-reactivity to clinically relevant profilins. METHODS: The release of Phl p allergens from pollen was determined by mass spectrometry and immunochemistry. T-cell responses, epitope mapping and cross-reactivity to profilins (Phl p 12, Ole e 2, Bet v 2 and Mal d 4) were measured in vitro using PBMCs from 26 Spanish grass-allergic donors IgE-sensitized to profilin. Cross-reactivity was addressed in vivo using 2 different mouse strains (BALB/c and C3H). RESULTS: Phl p 12 and Phl p 1 are released from pollen simultaneously and in similar amounts. Both T-cell response frequency (17/26 donors) and strength were comparable between Phl p 12 and Phl p 1. T-cell cross-reactivity to other profilins correlated with overall sequence homology, and 2 immunodominant epitope regions of Phl p 12 were identified. Data from mice immunized with Phl p 12 showed that cross-reactivity to Bet v 2 was mediated by conserved epitopes and further influenced by additional genetic factors, likely to be MHC II. CONCLUSION: The strength, prevalence and cross-reactivity of T-cell responses towards Phl p 12 are comparable to the major allergen Phl p 1, which supports the hypothesis that T cells to Phl p 12 can play an important role in development of allergic symptoms, such as those associated with pollen-food syndrome.

Phase II/III clinical trial to assess the tolerability and immunological effect of a new updosing phase of Dermatophagoides mix-based immunotherapy.

BACKGROUND: Immunologically enhanced subcutaneous specific immunotherapy (SCIT) has been developed with a fast and simplified updosing phase containing equal parts of the house dust mites (HDM) Dermatophagoides pteronyssinus and Dermatophagoides farinae (Dermatophagoides mix) adsorbed on aluminum hydroxide. OBJECTIVE: To evaluate the tolerability and immunological impact of the updosing phase of this new allergen extract formulation. MATERIAL AND METHODS: We performed a multicenter, open-label, single-arm, phase II/III clinical trial. The inclusion criteria were a clinical history of rhinitis/conjunctivitis due to HDM (with/without asthma) and sensitization to HDM (positive specific IgE and skin prick test). Five updosing injections of Dermatophagoides mix (300, 600, 3000, 6000, and 15000 SQ+) were administered at weekly intervals with 1 maintenance injection (15000 SQ+) 2 weeks after the last updosing injection. Two days after each visit, patients were contacted by telephone to follow up on any adverse events. IgE-blocking factor, IgG4, and immediate skin reactivity were evaluated. RESULTS: The sample comprised 102 patients (mean [SD] age, 29.3 [7.7] years; male, 52.9%). There were 117 adverse drug reactions (ADR): 101 were local, regardless of reaction size, in 48 (47.1%) patients and 7 were systemic (all grade I) in 5 (4.9%) patients. All ADRs were mild, except for 1, which was moderate. Six weeks of treatment led to statistically significant increases in IgE-blocking factor and IgG4, as well as a significant reduction in immediate skin reactivity. CONCLUSION: This new updosing phase of Dermatophagoides mix-based immunotherapy had a good tolerability profile and induced a significant immunological effect.

Phase II/III clinical trial to assess the tolerability and immunological effect of a new updosing phase of dermatophagoides mix–based immunotherapy

Background: Immunologically enhanced subcutaneous specific immunotherapy (SCIT) has been developed with a fast and simplified updosing phase containing equal parts of the house dust mites (HDM) Dermatophagoides pteronyssinus and Dermatophagoides farina ( Dermatophagoides mix) adsorbed on aluminum hydroxide. Objective: To evaluate the tolerability and immunological impact of the updosing phase of this new allergen extract formulation. Material and Methods: We performed a multicenter, open-label, single-arm, phase II/III clinical trial. The inclusion criteria were a clinical history of rhinitis/conjunctivitis due to HDM (with/without asthma) and sensitization to HDM (positive specific IgE and skin prick test). Five updosing injections of Dermatophagoides mix (300, 600, 3000, 6000, and 15 000 SQ+) were administered at weekly intervals with 1 maintenance injection (15 000 SQ+) 2 weeks after the last updosing injection. Two days after each visit, patients were contacted by telephone to follow up on any adverse events. IgE-blocking factor, IgG4, and immediate skin reactivity were evaluated. Results: The sample comprised 102 patients (mean [SD] age, 29.3 [7.7] years; male, 52.9%). There were 117 adverse drug reactions (ADR): 101 were local, regardless of reaction size, in 48 (47.1%) patients and 7 were systemic (all grade I) in 5 (4.9%) patients. All ADRs were mild, except for 1, which was moderate. Six weeks of treatment led to statistically significant increases in IgE-blocking factor and IgG4, as well as a significant reduction in immediate skin reactivity. Conclusion: This new updosing phase of Dermatophagoides mix–based immunotherapy had a good tolerability profile and induced a significant immunological effect (AU)

Antecedentes: Se ha desarrollado una mejorada vacuna de inmunoterapia específica (SCIT) adsorbida en hidróxido de aluminio y administración subcutánea con una fase de incremento de dosis más rápida y simplificada que contiene D. pteronyssinus y D. farinae (HDM; Dermatophagoides mezcla) a partes iguales. Objectivo: Evaluar la tolerabilidad de la fase de incremento de dosis de esta nueva formulación de extracto alergénico en SCIT y su impacto inmunológico. Material y Métodos: Ensayo clínico multicéntrico, abierto, de un brazo, fase II/III. Los sujetos que se podían incluir eran pacientes con una historia clínica de rinitis/conjuntivitis a ácaros de polvo doméstico (con/sin asma) y que presentaran sensibilización a HDM (IgE específica y prueba cutánea positiva). Se administraron cinco dosis semanales de Dermatophagoides mezcla en la fase de inicio (300, 600, 3000, 6000 y 15.000 SQ+) y una inyección de mantenimiento (15.000 SQ+) dos semanas tras la última inyección de la fase de incremento de dosis. Dos días tras cada visita se contactó con los pacientes por teléfono para seguir cualquier acontecimiento adverso (AE). Además, se evaluaron la IgG4, factor bloqueante de IgE y la respuesta cutánea inmediata. Resultados: Se incluyeron 102 sujetos en el ensayo (52,9% varones) con una edad media de 29,3±7,7 años. Se notificaron 117 reacciones adversas (RA) relacionadas con el medicamento en investigación: 101 locales, con independencia del tamaño de la reacción, en 48 (47,1%) pacientes y 7 sistémicas, todas grado I, en 5 (4,9%) pacientes. Todas las RA fueron de intensidad leve, excepto una, de intensidad moderada. Tras seis semanas de tratamiento, se obtuvieron incrementos estadísticamente significativos en el factor bloqueante de IgE y en IgG4, así como en la reducción de la respuesta cutánea inmediata. Conclusión: Esta nueva fase de incremento de dosis con inmunoterapia con Dermatophagoides mezcla presenta un buen perfil de tolerabilidad e induce una respuesta inmunológica significativa (AU)

Six-coordinate nitrosyl and nitro complexes of meso-tetratolylporphyrinatocobalt with trans sulfur-donor ligands.

By Fourier transform infrared and optical spectroscopy, it has been observed that interactions of dimethyl sulfide and tetrahydrothiophene with nitrosyl and nitro complexes of meso-tetra-p-tolylporphyrinatocobalt [Co(TTP)] lead to the formation of previously unknown six-coordinate species. Nitrosyl complexes of the general formula (S-donor)Co(TTP)(NO) are thermally unstable and can be seen only at low temperatures both in the solid state and in solution. The nitro complexes (S-donor)Co(TTP)(NO(2)) are fairly stable at room temperature in the solid state but partly decompose upon dissolution. The binding constants for these complexation reactions were determined. In contrast to the solid-state iron nitritoporphyrin complexes, oxo-transfer reactions from the coordinated nitro group of Co(TTP)(NO(2)) to the S donors, resulting in oxidation of these sulfides and the formation of Co(TTP)(NO), were not observed.

The Leishmania amazonensis TRF (TTAGGG repeat-binding factor) homologue binds and co-localizes with telomeres.

BACKGROUND: Telomeres are specialized structures at the end of chromosomes essential for maintaining genome stability and cell viability. The importance of telomeric proteins for telomere maintenance has increased our interest in the identification of homologues within the genus Leishmania. The mammalian TRF1 and TRF2 proteins, for example, bind double-stranded telomeres via a Myb-like DNA-binding domain and are involved with telomere length regulation and chromosome end protection. In addition, TRF2 can modulate the activity of several enzymes and influence the conformation of telomeric DNA. In this work, we identified and characterized a Leishmania protein (LaTRF) homologous to both mammalian TRF1 and TRF2. RESULTS: LaTRF was cloned using a PCR-based strategy. ClustalW and bl2seq sequence analysis showed that LaTRF shared sequence identity with the Trypanosoma brucei TRF (TbTRF) protein and had the same degree of sequence similarities with the dimerization (TRFH) and the canonical DNA-binding Myb-like domains of both mammalian TRFs. LaTRF was predicted to be an 82.5 kDa protein, indicating that it is double the size of the trypanosome TRF homologues. Western blot and indirect immunofluorescence combined with fluorescence in situ hybridization showed that LaTRF, similarly to hTRF2, is a nuclear protein that also associates with parasite telomeres. Native and full length LaTRF and a mutant bearing the putative Myb-like domain expressed in bacteria bound double-stranded telomeric DNA in vitro. Chromatin immunoprecipitation showed that LaTRF interacted specifically with telomeres in vivo. CONCLUSION: The nuclear localization of LaTRF, its association and co-localization with parasite telomeres and its high identity with TbTRF protein, support the hypothesis that LaTRF is a Leishmania telomeric protein.