ABSTRACT
We show that in spatially resolved reflectance anisotropy (RA) spectrometers, off-axis optical rays introduce a spurious signal component that cannot be addressed by optical alignment. Such a component is associated with the difference between the reflectivities s and p of the sample and depends, in a complex manner, on the incidence position of the incident light on the surface of the sample. We report a data-reduction procedure to easily identify and remove spurious RA signals associated with the off-axis optical rays, based on the singular value decomposition analysis of spatially resolved RA spectra. We validated this approach by developing a spatially resolved RA spectrometer based on an 8 × 8 multi-anode photomultiplier (PMT). The PMT allowed the use of phase-sensitive detection techniques to enhance the signal-to-noise ratio, which is essential for the evaluation of the proposed data reduction procedure.
ABSTRACT
Objetivo: Existe poca información sobre los resultados funcionales y cognitivos a largo plazo en pacientes con hemorragia subaracnoidea aneurismática (HSA). El objetivo principal fue evaluar la situación cognitiva, funcional, anímica y la calidad de vida en personas con HSA a largo plazo. Pacientes y método: Estudio de corte transversal de una cohorte de 40 pacientes (edad media 58,2 [DE 9,9] años) con HSA ingresados en la unidad de Rehabilitación neurológica entre enero del 2010 a julio del 2017. Variables de resultado: estado cognitivo (cuestionario de Pfeiffer), nivel funcional (índice de Barthel), depresión (escala de Hamilton) y calidad de vida (European Quality of Life-5 Dimensions [EQ-5D]), así como las terapias de rehabilitación realizadas en un seguimiento mínimo de seis meses post-HSA. Resultados: De 35 pacientes con alteraciones cognitivas en fase aguda, solo 12 realizaron terapia cognitiva tras el alta hospitalaria. En el seguimiento a largo plazo, los déficits cognitivos persistían en 22 casos, y en comparación con el resto, presentaban peores puntuaciones en el índice de Barthel (15,5 [IC 95% 1,2 a 29,7]), la escala de Hamilton (-0,8 [IC 95% -1,27 a -0,37]), y la EQ-5D (27,6 [IC 95% 12,4 a 19]). Conclusión: La prevalencia de déficits cognitivos a largo plazo en supervivientes de una HSA es alta y su presencia se relaciona con un peor estado funcional, más depresión y peor calidad de vida. El bajo porcentaje de individuos que realizan terapia cognitiva en su proceso de rehabilitación junto con las repercusiones clínicas observadas apoyan la necesidad de incluir las terapias neurocognitivas en los programas de rehabilitación de las HSA.(AU)
Objective: Little data is available on long-term functional and cognitive outcomes in patients with aneurysmal subarachnoid hemorrhage (ASH). The main objective of this study was to assess cognition, functional state, mood disorders, and quality of life in patients with SAH at least six months following the ASH. Patients and methods: Cross-sectional study of 40 patients (aged 58.2 [SD 9.9] years) with ASH, discharged from a Neurologic Rehabilitation unit between January 2010 and July 2017. Main outcome variables: functional status (Barthel index), cognition (Pfeiffer questionnaire), depression (Hamilton scale), and health-related quality of life (European Quality of Life-5 Dimensions [EQ-5D]), as well as type and duration of therapeutic rehabilitation procedures after discharge. Results: From 35 patients with cognitive disorders, only 12 received cognitive therapy at hospital discharge. In the long-term follow-up, cognitive impairment persisted in 22 patients. When compared with those without cognitive impairment, they presented significantly worse mean differences in the Barthel index (15.5 [95% CI: 1.2-29.7]), Hamilton scale (-0.8 [95% CI: -1.27 to -0.37]), and EQ-5D (27.6 [95% CI: 12.4-19]). Conclusion: The prevalence of long-term cognitive impairments in survivors of a SAH episode is high, and their presence is associated with worse functional status, more depression and worse quality of life. The low percentage of subjects who received cognitive therapies through their recovery process and the clinical implications observed, support the need of including neuropsychological therapies in the rehabilitation programs after an SAH event.(AU)
Subject(s)
Humans , Male , Female , Young Adult , Adult , Middle Aged , Aged , Aged, 80 and over , Cognition , Quality of Life/psychology , Subarachnoid Hemorrhage/complications , Subarachnoid Hemorrhage/psychology , Survivors , Affect , Neurological Rehabilitation , Cognitive Behavioral Therapy , Depression/therapy , Cross-Sectional Studies , Cohort Studies , Retrospective Studies , RehabilitationABSTRACT
OBJECTIVE: Little data is available on long-term functional and cognitive outcomes in patients with aneurysmal subarachnoid hemorrhage (ASH). The main objective of this study was to assess cognition, functional state, mood disorders, and quality of life in patients with SAH at least six months following the ASH. PATIENTS AND METHODS: Cross-sectional study of 40 patients (aged 58.2 [SD 9.9] years) with ASH, discharged from a Neurologic Rehabilitation unit between January 2010 and July 2017. MAIN OUTCOME VARIABLES: functional status (Barthel index), cognition (Pfeiffer questionnaire), depression (Hamilton scale), and health-related quality of life (European Quality of Life-5 Dimensions [EQ-5D]), as well as type and duration of therapeutic rehabilitation procedures after discharge. RESULTS: From 35 patients with cognitive disorders, only 12 received cognitive therapy at hospital discharge. In the long-term follow-up, cognitive impairment persisted in 22 patients. When compared with those without cognitive impairment, they presented significantly worse mean differences in the Barthel index (15.5 [95% CI: 1.2-29.7]), Hamilton scale (-0.8 [95% CI: -1.27 to -0.37]), and EQ-5D (27.6 [95% CI: 12.4-19]). CONCLUSION: The prevalence of long-term cognitive impairments in survivors of a SAH episode is high, and their presence is associated with worse functional status, more depression and worse quality of life. The low percentage of subjects who received cognitive therapies through their recovery process and the clinical implications observed, support the need of including neuropsychological therapies in the rehabilitation programs after an SAH event.
Subject(s)
Subarachnoid Hemorrhage , Cognition , Cross-Sectional Studies , Functional Status , Humans , Quality of Life/psychology , Retrospective Studies , Subarachnoid Hemorrhage/complications , Subarachnoid Hemorrhage/psychology , SurvivorsABSTRACT
Retinal Müller glial cells (MGs) are among the first to demonstrate metabolic changes during retinal disease and are a potential source of regenerative cells. In response to a harmful stimulus, they can dedifferentiate acquiring neural stem cells properties, proliferate and migrate to the damaged retinal layer and differentiate into lost neurons. However, it is not yet known how this reprogramming process is regulated in mammals. Since glucose and oxygen are important regulatory elements that may help directing stem cell fate, we aimed to study the effect of glucose variations and oxidative stress in Müller cells reprogramming capacity and analyze the participation the histone deacetylase SIRT6, as an epigenetic modulator of this process. We found that the combination of high glucose and oxidative stress induced a decrease in the levels of the marker glutamine synthetase, and an increase in the migration capacity of the cells suggesting that these experimental conditions could induce some degree of dedifferentiation and favor the migration ability. High glucose induced an increase in the levels of the pluripotent factor SOX9 and a decrease in SIRT6 levels accompanied by the increase in the acetylation levels of H3K9. Inhibiting SIRT6 expression by siRNA rendered an increase in SOX9 levels. We also determined SOX9 levels in retinas from mice with a conditional deletion of SIRT6 in the CNS. To further understand the mechanisms that regulate MGs response under metabolic impaired conditions, we evaluated the gene expression profile and performed Gene Ontology enrichment analysis of Müller cells from a murine model of Diabetes. We found several differentially expressed genes and observed that the transcriptomic change involved the enrichment of genes associated with glucose metabolism, cell migration, development and pluripotency. We found that many functional categories affected in cells of diabetic animals were directly related to SIRT6 function. Transcription factors enrichment analysis allowed us to predict several factors, including SOX9, that may be involved in the modulation of the differential expression program observed in diabetic MGs. Our results underline the heterogeneity of Müller cells response and the challenge that the study of metabolic impairment in vivo represents.
ABSTRACT
PURPOSE: Abnormally invasive placenta is an important cause of maternal morbidity, and its primary complication is massive bleeding. Strategies for preventing bleeding include arterial endovascular occlusion. One concern with the use of intra-arterial occlusion balloons is radiation exposure to the fetus, which occurs while determining balloon position. In this study, we sought to determine the radiation absorbed dose by the fetus during intra-aortic occlusion balloon placement in patients with abnormally invasive placenta. MATERIALS AND METHODS: We estimated the fetal absorbed dose and the entrance skin dose in the vaginal fundus and lumbar skin, respectively, using thermoluminescent dosimeter crystals, during intra-aortic balloon positioning using the mobile X-ray image intensifier system (C-arm) in digital radiography mode, directly in surgery room, without transfer to angiographic suite. We also performed a mannequin-based simulation to validate the entrance skin dose measurement technique. RESULTS: Ten women undergoing surgical management of an abnormally invasive placenta, in whom the location of the intra-aortic occlusion balloon was verified using plain radiography with C-arm in the surgery room, were included in the study. Following maternal and fetal radiation exposure, the entrance skin dose and radiation absorbed dose by the fetus were 1.31 ± 0.96 mGy and 0.27 ± 0.28 mGy, respectively, with radiation exposure durations of <1 s. CONCLUSIONS: There were no complications with the use of REBOA, the radiation absorbed dose by the fetus, entrance skin dose, and duration of radiation exposure during intra-aortic occlusion balloon placement were lower than those reported for other vascular occlusion techniques, being this a safe procedure.
Subject(s)
Balloon Occlusion , Placenta Accreta , Female , Fetus , Humans , Placenta/diagnostic imaging , Placenta Accreta/therapy , Pregnancy , Retrospective StudiesABSTRACT
In order to establish cancer-type-specific electroporation protocols for breast cancer, electroporation was performed in vitro in two modalities: in-suspension and adhered cells. Electroporation of cell suspensions was carried out through commercial electroporation cuvettes whereas a novel electrode for electroporation of adhered cells was designed and manufactured aimed to preserve cell structure, to provide a closer model to an in vivo scenario, and as a means to visualize the mechanical effects of electroporation on the cell membrane by using scanning electron microscopy. Electroporation protocols and electric field thresholds were predicted in silico and experimentally tuned through propidium iodide uptake and cell viability. Three breast-cancer cell lines (BT-20, MCF-7 and HCC1419) and a non-cancerous cell line (BEAS-2B) were used. Cancerous cells responded differently to electroporation depending on the electric parameters, cell histology, the cell culture modality, and the cell morphology (membrane thickness mainly), which was evaluated trough confocal and transmission electron microscopy. Particularly, it was found that electrochemotherapy may represent a promising alternative as an adjuvant treatment of metastatic breast tumours, and as a neoadjuvant therapy for Her2/neu tumours. Oppositely, triple negative breast tumours may show a high sensitivity to electroporation and therefore, they could be efficiently treated with irreversible electroporation. On the other hand, noncancerous cells demanded the highest voltage in both cell culture modalities in order to be electroporated. Hence, these cells in suspension may provide a reliable, easy-to-perform, low-cost model for the development of electroporation protocols for eradication of healthy tissue around a tumour in a safety margin.
Subject(s)
Breast Neoplasms/pathology , Cell Adhesion , Electroporation/methods , Cell Survival , Humans , MCF-7 Cells , SuspensionsABSTRACT
The genus Hannemania includes 25 species of parasites of amphibians; Chile has one species: H. pattoni Sambon, 1928. This work reviews the genus Hannemania and describes two new species from Chile: Hannemania ortizi sp. nov., a parasite of Pleurodema thaul (Lesson) (Anura: Leptodactylidae) and Eupsophus contulmoensis Ortiz, Ibarra-Vidal, Formas (Anura: Alsodidae) and Hannemania gonzaleacunae sp. nov., a parasite of E. nahuelbutensis Ortiz and Ibarra-Vidal (Anura: Alsodidae). The new species differ from H. pattoni and other nearby species principally by character states of the palp and leg setae. A comparison of the diagnostic characters for all species of Hannemania is included.
Subject(s)
Anura/parasitology , Mite Infestations/veterinary , Mites/classification , Animals , Chile , Mite Infestations/parasitology , Mites/anatomy & histologyABSTRACT
The aim of this study was to assess the effect of a complete nitrite replacement strategy using celery, carmine, sodium lactate and orange dietary fibre combined with vitamins C and E, on the quality characteristics (technological, sensorial and safety properties) of hot dog sausages (five samples) during chilled storage (2 ± 1â 60 days). Nitrite replacers (combined with vitamins C and E) presented antioxidant activity, reducing lipid oxidation in reformulated samples. At the end of storage redness (a*) was similar in the control sample (with added nitrite) and in the sample without added nitrite. Sensory evaluation detected no significant difference between samples with and without added nitrite. All the reformulated samples were judged acceptable by the panellists. At the end of storage, the control sample contained more than four times as much residual nitrite as the reformulated samples. Growth of presumptive Clostridium perfringens was not observed in any of the samples. Samples without added nitrite had longer shelf-lives than control sausage. Samples containing 0.1% vitamin C registered the lowest microbiological levels. This strategy could be a good alternative to reduce and/or eliminate added nitrite in hot dog sausages.
Subject(s)
Anti-Infective Agents/pharmacology , Antioxidants/pharmacology , Food Handling/methods , Food Preservation/methods , Meat Products/analysis , Nitrites , Taste , Animals , Apium , Ascorbic Acid/pharmacology , Carmine/pharmacology , Cattle , Citrus/chemistry , Clostridium perfringens/drug effects , Clostridium perfringens/growth & development , Dietary Fiber , Food Microbiology , Food Storage/methods , Humans , Lipid Peroxidation/drug effects , Meat Products/microbiology , Sodium Lactate/pharmacology , Vitamin E/pharmacologyABSTRACT
This research deals with the application of a global strategy designed to produce a nitrite-free Asian hot dog. Different ingredients such as annatto, cochineal, orange dietary fibre, vitamins E and C, lactate and celery were combined in order to study the appearance (colour), lipid oxidation stability and microbial stability of the nitrite-free formulations. The control sample contained much more (P < 0.05) residual nitrite (88.7 mg/kg) than the samples without added nitrite (23-24 mg/kg). Generally, no formulation-dependent variations were observed in fat and water binding properties. Control sample had the highest L* and a* values, while the product with annatto (RA) had the lowest a* values. Lipid oxidation levels were similar irrespective of formulation. The hot dog reformulated with cochineal (RC) scored higher for overall acceptability than RA, mainly due to its colour.
ABSTRACT
This work presents an algorithm to determine instantaneous orientation of an object in 3D space. The orientation was determined by using a Direction Cosine Matrix (DCM), performed by the combination of three consecutive rotations, around each to the main axes of the evaluated system, using quaternions. An inertial measurement unit (IMU), consisting of 3 axes gyroscope and 3 axes accelerometer was used in order to establish 2 coordinate systems; The first one describes object movement, by using gyroscope as a main source of information, relating the angular rate of change along time. The second defines a coordinate reference system, relating the acceleration of gravity to an inertial direction vector. A proportional integral (PI) feedback controller was used, which includes sensors information, eliminating offset, cancelling drift and improving the accuracy of the orientation. The proposed algorithm can be used for assessing both the position and orientation of the body segments which is very important in orthopedic, traumatology and rheumatology important for diagnosis, prognostic, therapeutic, research and as well as the design and fabrication of measuring devices used in surgical instrumentation, prostheses and ortheses. It is important to note that the developed system opens the opportunities to be implemented on ambulatory joint evaluation through a wearable system, due to the dimensions and requirements of the sensors.
El presente trabajo presenta un algoritmo para determinar la orientación instantánea de un objeto en el espacio 3D. La orientación fue determinada utilizando una matriz de cosenos directores (DCM) conformada por la combinación de 3 rotaciones consecutivas alrededor de cada uno de los ejes del sistema evaluado, utilizando cuaterniones. Una unidad inercial de medida (IMU) compuesta por un giroscopio de 3 ejes y un acelerómetro de 3 ejes fue utilizada con el objetivo de establecer 2 sistemas coordenados; Un sistema coordenado describiendo el movimiento del objeto, utilizando al giroscopio como fuente principal de información, estableciendo la relación de cambio con respecto al tiempo. Un sistema coordenado de referencia, relacionando la aceleración gravitacional a un vector inercial. Un control por retroalimentación proporcional integral (PI) fue utilizado con el objetivo de combinar la información de los sensores, eliminando las desviaciones por offset y deriva, mejorando la precisión en la orientación. Dadas sus características, el algoritmo propuesto permite su utilización en la evaluación de la posición y la orientación de los segmentos corporales, siendo de suma importancia en ortopedia, traumatología y reumatología para la determinación de diagnósticos, pronósticos terapéuticos e investigación así como el diseño y fabricación de dispositivos de medición, instrumentación quirúrgica, prótesis y ortesis. Cabe destacar que el sistema desarrollado abre oportunidades de ser implementado en el diseño de sistemas ambulatorios de evaluación de las articulaciones, mediante el uso de elementos transportables dadas las reducidas dimensiones y limitaciones de los sensores empleados.
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Deterministic hydrodynamic polishing with HyDRa requires a precise control of polishing parameters, such as propelling air pressure, slurry density, slurry flux and tool height. We describe the HyDRa polishing system and prove how precise, deterministic polishing can be achieved in terms of the control of these parameters. The polishing results of an 84 cm hyperbolic mirror are presented to illustrate how the stability of these parameters is important to obtain high-quality surfaces.
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The aim of this work was to determine the structure of the benthic entomofauna and its variation along the El Tala River (Catamarca, Argentina). Five sampling stations were established, considering the location of nearby housing with respect to the watercourse. The following variables were determined in situ: altitude, latitude and longitude, bedstream width, river depth, river-current speed, water and air temperatures. Benthic insects were collected with a square parcel sampler of 0.09-m2 area and 300-µm net opening and identified to the family level. Faunal density, richness, and diversity exhibited a longitudinal variation. From sampling Stations 1 (reference site) to 3, the number of orders and families decreased, whereas in sampling Station 4 those values increased and continued to do so through to Station 5 (downstream station). Station 5 showed the highest family richness (17) and the highest value for the Shannon-Wiener index (2.74) and the lowest value in Simpson's Dominance index (D = 0.22). These values could be explained because of the self-cleansing capabilities of the river downstream. The water quality of El Tala River is Class I (very clean and non-impacted), according to the results obtained from the application of the biotic Biological-Monitoring-Working-Party and Average-Store-per-Taxon indices.
Subject(s)
Biodiversity , Environmental Monitoring/methods , Insecta/classification , Rivers , Water Quality , Animals , Argentina , Population Dynamics , Seasons , Temperature , Water MovementsABSTRACT
Continuous culture of fresh water microalgae Scenedesmus obliquus was developed in a two-stage photobioreactor, avoiding the intermediate harvesting step to achieve a half-way point between the progressive and the sudden N-starvation strategies, guaranteeing light limited conditions in the first stage and N-stress conditions in the second stage. This methodology resulted in biomass productivity values at the best dilution rate (0.118 days(-1)) of 15.25±1.06 g m(-2) d(-1), slightly higher than that expected according to batch experiment (12.90±0.75 g m(-2) d(-1)). The dilution rate that maximized the lipid content was coincident with that for the maximum biomass productivity, resulting in a intensification of the lipid productivity. Microalgae can be successfully cultured in reused medium clarified by high pH flocculation-sedimentation and neutralized by bubbling the photobioreactors outlet CO2 current through it. Microalgae flocculation with NaOH does not result in a variation of the obtained lipid profile.
Subject(s)
Biomass , Bioreactors , Lipid Metabolism , Lipids/biosynthesis , Scenedesmus/metabolism , Photochemical ProcessesABSTRACT
High pH-induced flocculation-sedimentation of Scenedesmus obliquus and Chlorella vulgaris was studied with the objective of improving the efficiency of microalgae harvesting, since it is one of the most expensive steps of production of microalgae. Desired pH values were achieved by addition of NaOH and Ca(OH)(2). Growth rate and lipid productivity in fresh media prepared with tap water and with analytical-grade water, and in reused media prepared with culture centrifuged supernatant and the supernatant from high pH-induced flocculation-sedimentation were compared. Since the growth rates for reused media were about 1.7 times higher than in fresh media, and the lipid productivities were about 25 and 26 mg L(-1) d(-1) in flocculated and centrifuged reused media respectively, medium reuse is a suitable method of saving water and nutrients.
Subject(s)
Cell Culture Techniques/methods , Chlorella vulgaris/physiology , Hydrogen-Ion Concentration , Lipids/biosynthesis , Scenedesmus/physiology , Cell Proliferation , FlocculationABSTRACT
The effect of replacing animal fat (0%, 50% and 80% of pork backfat) by an equal proportion of konjac gel, on processing and quality characteristics of reduced and low-fat dry fermented sausage was studied. Weight loss, pH, and water activity of the sausage were affected (P<0.05) by fat reduction and processing time. Low lipid oxidation levels were observed during processing time irrespective of the dry sausage formulation. The fat content for normal-fat (NF), reduced-fat (RF) and low-fat (LF) sausages was 29.96%, 19.69% and 13.79%, respectively. This means an energy reduction of about 14.8% for RF and 24.5% for LF. As the fat content decreases there is an increase (P<0.05) in hardness and chewiness and a decrease (P<0.05) in cohesiveness. No differences were appreciated (P>0.05) in the presence of microorganisms as a result of the reformulation. The sensory panel considered that NF and RF products had acceptable sensory characteristics.
Subject(s)
Adipose Tissue , Amorphophallus , Dietary Fats , Food Handling/methods , Meat Products/analysis , Taste , Animals , Diet, Fat-Restricted , Energy Intake , Fermentation , Gels , Humans , Hydrogen-Ion Concentration , Lipid Peroxidation , Meat Products/standards , Swine , Water/physiologyABSTRACT
Descreve-se o primeiro caso de paratuberculose em veado pudu-do-sul (Pudu pudu). O animal foi encontrado na cidade de Concepción, centro sul do Chile, em péssimas condições e com sinais claros de diarréia. Internamente apresentava séria atrofia de gordura no coração, lesões histológicas nos pulmões, fígado, baço e rins, e injúrias intestinais. Diferentes amostras foram preparadas com Ziehl-Neelsen, e os linfonodos mesentéricos presentes no íleo foram fortemente positivos para a bactéria resistente ao ácido.
Subject(s)
Animals , Male , Deer , Paratuberculosis , Animals, Wild , ChileABSTRACT
In this paper, an optical design is presented for an anastigmatic telescope with back focal length corrected with exact ray tracing to eliminate spherical, coma, and astigmatism aberrations. The telescope is formed of three conical mirrors, two of them polished on the same substratum. The optical design is divided into three stages: we began the design obtaining the Gaussian parameters in a first-order solution; posteriorly, were obtained analytically the three mirrors' asphericity in a third-order design. The final design stage consists of the implementation of the Fermat's principle, the Abbe sine condition, and the Coddington equations for the exact correction for the three aforementioned aberrations.
ABSTRACT
Healthier lipid pâtés were formulated by reducing the fat content and/or replacing the pork backfat by a healthier oil combination (olive, linseed and fish oils) and konjac gel (0-15%). The reformulation results were evaluated by composition (proximate analysis and fatty acid profile), technological properties (emulsion stability, colour, and texture), microbiological and sensory parameters of the pâtés. Pâtés with partial or total replacement of pork backfat had lower levels of saturated fatty acids (SFA) (27.4% and 21.3%) and monounsaturated fatty acids (MUFA) (49.8% and 42.5%), and higher levels of polyunsaturated fatty acids (PUFA) (22.4% and 35.6%) compared with control pâtés (32.2%, 58.2% and 9.04% respectively). The n-6/n-3 PUFA ratio was decreased from 6.78 (in control pâtés) to 0.79 and 0.48 when partial and total pork backfat respectively was replaced by a healthier oil combination. Although emulsion stability was affected by the formulation, in general all pâtés had good fat and water binding properties. The fat reduction produced a softer and more spreadable pâté, although no effect on penetration parameters was observed after by pork fat replacement by a healthier oil combination. The addition of 15% of konjac gel produced stiffer structures (as compared with 0 and 7%) which are very close to those of the control samples. No microbiological limitations were produced by the reformulation process, obtaining pâtés with acceptable sensory characteristics, similar to the control sample.
Subject(s)
Amorphophallus , Dietary Fats/analysis , Fatty Acids/analysis , Functional Food , Meat Products/analysis , Plant Preparations , Animals , Emulsions/chemistry , Fish Oils , Gels , Linseed Oil , Liver , Meat Products/microbiology , Olive Oil , Plant Oils , Swine , Water/chemistryABSTRACT
A total of 687 adult nematomorphs of four species of Gordiida: Chordodes brasiliensis (393 specimens), Noteochorododes cymatium (47 specimens), N. talensis (162 specimens) and Pseudochordodes dugesi (85 specimens) were collected during a period of 1 year from El Simbolar stream, Argentina. Free-living worms were abundant during autumn and spring, but their number decreased during winter and summer. Males were shorter and significantly more abundant than females. The presence of N. cymatium, N. talensis and P. dugesi was correlated with water temperature and these species were most abundant in winter and spring. The presence of C. brasiliensis was correlated with flow rate and pH; this species was more abundant in autumn and winter. These four species are sympatric.
Subject(s)
Helminths/anatomy & histology , Helminths/isolation & purification , Sex Characteristics , Animals , Argentina , Female , Helminths/physiology , Hydrogen-Ion Concentration , Male , Microscopy , Seasons , Water/chemistryABSTRACT
Strategies for life adaptation to extreme environments often lead to novel solutions. As an example of this assertion, here we describe the first species of the well-known genus of green unicellular alga Dunaliella able to thrive in a subaerial habitat. All previously reported members of this microalga are found in extremely saline aquatic environments. Strikingly, the new species was found on the walls of a cave located in the Atacama Desert (Chile). Moreover, on further inspection we noticed that it grows upon spiderwebs attached to the walls of the entrance-twilight transition zone of the cave. This peculiar growth habitat suggests that this Dunaliella species uses air moisture condensing on the spiderweb silk threads as a source of water for doing photosynthesis in the driest desert of the world. This process of adaptation recapitulates the transition that allowed land colonization by primitive plants and shows an unexpected way of expansion of the life habitability range by a microbial species.