59 research outputs found

    Clinical, imaging and genetic analysis of double bilateral radix entomolaris

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    Background: Anatomy describes that first mandibular molars have two roots: 1 mesial, with 2 root canals, and 1 distal, with 1 root canal. The presence of three roots in these teeth is uncommon. Root anatomical variations have an impact, especially in endodontic, where the highest rates of nonsurgical treatment failures are due to the inability to identify and access roots and/or accessory canals. The aim of this research is to report a case of double three-rooted mandibular first molar through clinical, imaging and genetic analysis. Materials and methods: Using a panoramic radiography, the presence of three roots in teeth 36 and 46 was diagnosed in a female patient. Additionally, it was indicated a cone beam computed tomography. Moreover, leukocyte genomic DNA was obtained from a blood sample of the patient to determine her ethnicity through analysis of mitochondrial DNA haplogroups using polymerase chain reaction-length restriction fragment polymorphism (PCR-RFLP). Results: Both molars had three roots, 1 mesial (M), 1 distolingual (DL), also known as radix entomolaris (RE), and a distovestibular (DV). For both teeth, M root had 2 canals, and DV and DL roots presented just 1 canal. Mitochondrial DNA analysis determined presence of haplogroup C, corresponding to Amerindian ethnicity. Conclusions: The presence of RE is uncommon. This case report contributes to describe this rare anatomical variation. To our knowledge, this is the first molecular-genetic study applied to dental anatomy and gives basis to develop future research in the area

    Modelling the Spatial and Temporal Dynamics of Paralytic Shellfish Toxins (PST) at Different Scales: Implications for Research and Management

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    Harmful algal blooms, in particular recurrent blooms of the dinoflagellate Alexandrium catenella, associated with paralytic shellfish poisoning (PSP), frequently limit commercial shellfish harvests, resulting in serious socio-economic consequences. Although the PSP-inducing species that threaten the most vulnerable commercial species of shellfish are very patchy and spatially heterogeneous in their distribution, the spatial and temporal scales of their effects have largely been ignored in monitoring programs and by researchers. In this study, we examined the spatial and temporal dynamics of PSP toxicity in the clam (Ameghinomya antiqua) in two fishing grounds in southern Chile (Ovalada Island and Low Bay). During the summer of 2009, both were affected by an intense toxic bloom of A. catenella (up to 1.1 × 106 cells L-1). Generalized linear models were used to assess the potential influence of different environmental variables on the field detoxification rates of PSP toxins over a period of 12 months. This was achieved using a four parameter exponential decay model to fit and compare field detoxification rates per sampling site. The results show differences in the spatial variability and temporal dynamics of PSP toxicity, given that greater toxicities (+10-fold) and faster detoxification (20% faster) are observed at the Ovalada Island site, the less oceanic zone, and where higher amounts of clam are annually produced. Our observations support the relevance of considering different spatial and temporal scales to obtain more accurate assessments of PSP accumulation and detoxification dynamics and to improve the efficacy of fisheries management after toxic events.This research was funded by FONDEF Project MR07I1007 from the 2nd Program on Red Tides and the project REDI170575 from the International Cooperation Programme of the Chilean National Commission for Scientific and Technological Research (CONICYT). Patricio A. Díaz is funded by the Centro de Biotecnología y Bioingeniería (CeBiB) (PIA project FB0001, ANID, Chile). Rosa I. Figueroa is funded by a national project from the Spanish Ministry of Science and Innovation and the European Community (FEDER) (Project DIANAS-CTM2017- 86066-R), a grant for Galician Networks of Excellence (GRC-VGO- HAB IN607A-2019/04) from the Innovation Agency of the Xunta de Galicia (GAIN) and the structural IEO-CSIC project CCVIEO-7.Peer reviewe

    Science Priorities for Seamounts: Research Links to Conservation and Management

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    Seamounts shape the topography of all ocean basins and can be hotspots of biological activity in the deep sea. The Census of Marine Life on Seamounts (CenSeam) was a field program that examined seamounts as part of the global Census of Marine Life (CoML) initiative from 2005 to 2010. CenSeam progressed seamount science by collating historical data, collecting new data, undertaking regional and global analyses of seamount biodiversity, mapping species and habitat distributions, challenging established paradigms of seamount ecology, developing new hypotheses, and documenting the impacts of human activities on seamounts. However, because of the large number of seamounts globally, much about the structure, function and connectivity of seamount ecosystems remains unexplored and unknown. Continual, and potentially increasing, threats to seamount resources from fishing and seabed mining are creating a pressing demand for research to inform conservation and management strategies. To meet this need, intensive science effort in the following areas will be needed: 1) Improved physical and biological data; of particular importance is information on seamount location, physical characteristics (e.g. habitat heterogeneity and complexity), more complete and intensive biodiversity inventories, and increased understanding of seamount connectivity and faunal dispersal; 2) New human impact data; these shall encompass better studies on the effects of human activities on seamount ecosystems, as well as monitoring long-term changes in seamount assemblages following impacts (e.g. recovery); 3) Global data repositories; there is a pressing need for more comprehensive fisheries catch and effort data, especially on the high seas, and compilation or maintenance of geological and biodiversity databases that underpin regional and global analyses; 4) Application of support tools in a data-poor environment; conservation and management will have to increasingly rely on predictive modelling techniques, critical evaluation of environmental surrogates as faunal “proxies”, and ecological risk assessment

    Spring northward juvenile migration of the Patagonian grenadier (Macruronus magellanicus) from the Northwest Patagonian waters of Chile

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    Important nursery grounds for Patagonian grenadier (Macruronus magellanicus) are located mainly in the Northwest Patagonian Inner Sea (42ÂșS-44ÂșS), from which juvenile must to disperse or migrate offshore, then along the Chilean coast either northward or southward. The objective of this paper was to estimate northward spring juvenile migration of the Patagonian grenadier from nursery to feeding areas, which are located near Talcahuano (35Âș00’S-37Âș10’S). Length-frequency data (LFD) were obtained from an acoustic survey carried out in November 1999, which covered from 35ÂșS to 47ÂșS. Generalized linear model was used to describe the presence of juvenile per latitude and depth, and to infer the origin and displacement of juveniles. Subsequently, LFD data were grouped according to latitudinal strata. Grouped LFD were decomposed into normal component groups, from which mean, standard deviation and proportion were estimated from the mixed LFD. The average length of the identified groups were sorted from south to north, and linked to compute significant increment in fish length and age per kilometers. The length increment per time was not due to growth, rather they was due to spatial displacement of juvenile from southern nursery grounds to northern feeding areas. Although homing to feeding areas and/or high residency (partial migration) have been postulated, it seems that recruitment of juveniles to northern feeding areas are origintaed from NPIS nurseries. The West Wind Drift Current seems to be the main drive for dispersion of Patagonian grenadier to recruit northward in open waters along the continental shelf

    Spatiotemporal analysis of the daily growth traits of the prerecruits of a small pelagic fish in response to enviromental drivers

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    [eng] A comparative analysis of daily growth patterns was carried out for prerecruits (PR) of Engraulis ringens, collected from spring to summer (2015-2016) in northern (18Âș25'S-24Âș40'S) and southern nursery areas (32Âș40'S-41Âș00'S) off the Chilean coast. Prerecruits ranged from 2.2 to 7.3 cm TL (4.27 ± 0.88) and from 27 to 102 days (54.68 ± 15.92) of age and were hatched mainly in spring 2015. Growth traits were addressed through otolith microstructure analysis to determine the increment width profiles (IW), back-calculated growth rates (BIGR), and overall absolute growth rates (AGR), whereas the Chl-a and sea-surface temperature (SST) variations were assessed by analyzing satellite and field-based data. The IWs (5.42 ± 1.94 ”m versus 1.02 ± 0.37 ”m), BIGRs (1.02 ± 0.37 versus 0.72 ± 0.26 mm·day−1), and AGRs (0.93 ± 0.15 versus 0.62 ± 0.08 mm·day−1) were significantly higher in the northern than in the southern stocks. The SST ranged from 17°C to 23°C (19.42 ± 1.45) and from 12°C to 18°C (14.81 ± 1.31) and varied significantly between stocks and months, whereas the higher concentration of Chl-α (~8 mg/m3), occurred close to the shallow coastal areas irrespective of stocks. A parabolic relationship between the recent otolith growth rates (ROGR) (as a proxy of recent daily somatic growth rates) and SST recorded at the date of capture estimated a maximum ROGR of 13.4 ”m·day−1 at 18°C. These results demonstrated that water temperature seemed to be an important daily growth controller for early juveniles of E. ringens in the Humboldt Current System and that the field-based growth-temperature relationship obtained will contribute to future potential bioenergetics models for this important forage species

    Expression of the carotenoid biosynthesis genes in Xanthophyllomyces dendrorhous

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    In the yeast Xanthophyllomyces dendrorhous the genes idi, crtE, crtYB, crtl and ast are involved in the biosynthesis of astaxanthin from isopentenyl pyrophosphate. The carotenoid production and the kinetics of mRNA expression of structural genes controlling the carotenogenesis in a wild-type ATCC 24230 and in carotenoid overproducer deregulated atxS2 strains were studied. The biosynthesis of carotenoid was induced at the late exponential growth phase in both strains. However, the cellular carotenoid concentration was four times higher in atxS2 than in the wild-type strain in the exponential growth phase, suggesting that carotenogenesis was deregulated in atxS2 at the beginning of growth. In addition, the maximum expression of the carotenogenesis genes at the mRNA level was observed during the induction period of carotenoid biosynthesis in the wild-type strain. The mRNA level of the crtYB, crtl, ast genes and to a lesser extent the idi gene, decayed at the end of the exponential growth phase. The mRNA levels of the crtE gene remained high along the whole growth curve of the yeast. In the atxS2 strain the mRNA levels of crtE gene were about two times higher than the wild-type strain in the early phase of the growth cycl
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