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1.
Animals (Basel) ; 14(1)2023 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-38200829

RESUMO

Non-contact devices have been used in the measurement of body temperature in livestock production as a tool for testing disease in different species. However, there are few studies about the variation and correlations in body temperature between rectal temperature (RT) and non-contact devices such as non-contact infrared thermometers (NCIT) and thermal imaging/infrared thermography (IRT). The objective of this work was to evaluate the accuracy of non-contact devices to measure the body temperature in sheep, considering six body regions and the possibility of implementing these systems in herd management. The experiment was carried out at the experimental farm of the Catholic University of Valencia, located in the municipality of Massanassa in July of 2021, with 72 dry manchega ewes, and we compared the rectal temperature with two types of non-contact infrared devices for the assessment of body temperature in healthy sheep. Except for the temperature taken by NCIT at the muzzle, the correlation between RT vs. NCIT or IRT showed a low significance or was difficult to use for practical flock management purposes. In addition, the variability between devices was high, which implies that measurements should be interpreted with caution in warm climates and open pens, such as most sheep farms in the Spanish Mediterranean area. The use of infrared cameras devices to assess body temperature may have a promising future, but in order to be widely applied as a routine management method on farms, the system needs to become cheaper, simpler in terms of measurements and quicker in terms of analyzing results.

2.
Mol Phylogenet Evol ; 125: 232-242, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29545110

RESUMO

Ancient lakes are renowned for their exceptional diversity of endemic species. As model systems for the study of sympatric speciation, it is necessary to understand whether a given hypothesized species flock is of monophyletic or polyphyletic origin. Here, we present the first molecular characterization of the Hyalella (Crustacea: Amphipoda) species complex of Lake Titicaca, using COI and 28S DNA sequences, including samples from the connected Small and Large Lakes that comprise Lake Titicaca as well as from a broader survey of southern South American sites. At least five evolutionarily distant lineages are present within Lake Titicaca, which were estimated to have diverged from one another 12-20 MYA. These major lineages are dispersed throughout the broader South American Hyalella phylogeny, with each lineage representing at least one independent colonization of the lake. Moreover, complex genetic relationships are revealed between Lake Titicaca individuals and those from surrounding water bodies, which may be explained by repeated dispersal into and out of the lake, combined with parallel intralacustrine diversification within two separate clades. Although further work in deeper waters will be required to determine the number of species present and modes of diversification, our results strongly indicate that this amphipod species cloud is polyphyletic with a complex geographic history.


Assuntos
Anfípodes/fisiologia , Lagos , Anfípodes/genética , Animais , Teorema de Bayes , Biodiversidade , Intervalos de Confiança , Especiação Genética , Geografia , Funções Verossimilhança , Filogenia , Especificidade da Espécie , Simpatria , Fatores de Tempo
3.
J Anim Sci ; 96(4): 1508-1518, 2018 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-29471469

RESUMO

The objective of this experiment was to find out the effect of lemon leaves on energy and C-N balances, methane emission, and milk performance in dairy goats. Lemon leaves were used to replace alfalfa as forage in a diet for Murciano-Granadina goats. Ten Murciano-Granadina dairy goats (44.1 ± 4.47 kg of BW) in late lactation (185 ± 7.2 d) were selected in a crossover design experiment, where each goat received 2 treatments in 2 periods. One group was fed a mixed ration with 450 g of pelleted alfalfa per kilogram of DM (ALF diet) and, the other group replaced alfalfa with 450 g of pelleted lemon leaves per kilogram DM (LEM diet). The concentrate was pelleted, being the same for the two groups (forage to concentrate ratio was 45/55). The goats were allocated to individual metabolism cages. After 14 d of adaptation, feed intake, total fecal and urine output, and milk yield were recorded daily over a 5-d period. Then, gas exchange measurements were recorded individually by an open-circuit indirect calorimetry system using a head box. Higher dietary lipids in LEM diet reduced DMI (200 g/d) and energy intake (251 kJ/kg of BW0.75), although no differences between treatments were observed for ME intake (998 kJ/kg of BW0.75, on average) and oxidation of nutrients (64% and 25% for carbohydrates and fat oxidation, respectively, on heat production from oxidation basis). Greater (P < 0.05) milk fat values for C18:2n6t and CLA 9c11t + 9t11c were found in LEM compared with ALF diet. Goats fed LEM diet produced significantly fewer CH4 emissions than ALF diet (18%). Likewise, the use of lemon leaves as forage reduced the amount of CH4 in 2.7 g/kg of milk. Results suggest that lemon leaves are effective in reducing CH4 emission without detrimental effect on milk yield.


Assuntos
Ração Animal/análise , Citrus , Ingestão de Energia , Cabras/fisiologia , Metano/metabolismo , Leite/metabolismo , Animais , Calorimetria/veterinária , Carbono/metabolismo , Dieta/veterinária , Ingestão de Alimentos , Fezes , Feminino , Lactação , Leite/química , Nitrogênio/metabolismo , Oxirredução , Folhas de Planta , Termogênese
4.
Curr Biol ; 28(2): 303-310.e3, 2018 01 22.
Artigo em Inglês | MEDLINE | ID: mdl-29337075

RESUMO

Thermomorphogenesis is defined as the suite of morphological changes that together are likely to contribute to adaptive growth acclimation to usually elevated ambient temperature [1, 2]. While many details of warmth-induced signal transduction are still elusive, parallels to light signaling recently became obvious (reviewed in [3]). It involves photoreceptors that can also sense changes in ambient temperature [3-5] and act, for example, by repressing protein activity of the central integrator of temperature information PHYTOCHROME-INTERACTING FACTOR 4 (PIF4 [6]). In addition, PIF4 transcript accumulation is tightly controlled by the evening complex member EARLY FLOWERING 3 [7, 8]. According to the current understanding, PIF4 activates growth-promoting genes directly but also via inducing auxin biosynthesis and signaling, resulting in cell elongation. Based on a mutagenesis screen in the model plant Arabidopsis thaliana for mutants with defects in temperature-induced hypocotyl elongation, we show here that both PIF4 and auxin function depend on brassinosteroids. Genetic and pharmacological analyses place brassinosteroids downstream of PIF4 and auxin. We found that brassinosteroids act via the transcription factor BRASSINAZOLE RESISTANT 1 (BZR1), which accumulates in the nucleus at high temperature, where it induces expression of growth-promoting genes. Furthermore, we show that at elevated temperature BZR1 binds to the promoter of PIF4, inducing its expression. These findings suggest that BZR1 functions in an amplifying feedforward loop involved in PIF4 activation. Although numerous negative regulators of PIF4 have been described, we identify BZR1 here as a true temperature-dependent positive regulator of PIF4, acting as a major growth coordinator.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Brassinosteroides/metabolismo , Proteínas Nucleares/genética , Desenvolvimento Vegetal/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Proteínas de Ligação a DNA , Temperatura Alta , Proteínas Nucleares/metabolismo , Reguladores de Crescimento de Plantas/metabolismo
5.
BMC Plant Biol ; 17(1): 114, 2017 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-28683779

RESUMO

BACKGROUND: Global increase in ambient temperatures constitute a significant challenge to wild and cultivated plant species. Forward genetic analyses of individual temperature-responsive traits have resulted in the identification of several signaling and response components. However, a comprehensive knowledge about temperature sensitivity of different developmental stages and the contribution of natural variation is still scarce and fragmented at best. RESULTS: Here, we systematically analyze thermomorphogenesis throughout a complete life cycle in ten natural Arabidopsis thaliana accessions grown under long day conditions in four different temperatures ranging from 16 to 28 °C. We used Q10, GxE, phenotypic divergence and correlation analyses to assess temperature sensitivity and genotype effects of more than 30 morphometric and developmental traits representing five phenotype classes. We found that genotype and temperature differentially affected plant growth and development with variing strengths. Furthermore, overall correlations among phenotypic temperature responses was relatively low which seems to be caused by differential capacities for temperature adaptations of individual accessions. CONCLUSION: Genotype-specific temperature responses may be attractive targets for future forward genetic approaches and accession-specific thermomorphogenesis maps may aid the assessment of functional relevance of known and novel regulatory components.


Assuntos
Arabidopsis/crescimento & desenvolvimento , Arabidopsis/genética , Interação Gene-Ambiente , Temperatura , Genótipo
6.
PLoS One ; 11(3): e0151215, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26983120

RESUMO

The aim of this experiment was to study the effects of substituting dietary barley grain with orange pulp or soybean hulls on energy, nitrogen and carbon balance, methane emission and milk performance in dairy goats. Twelve Murciano-Granadina dairy goats in midlactation were selected and divided into three groups based on similar body weight (42.1 ± 1.2 kg) and milk yield (2.16 ± 0.060 kg/goat/day). The experiment was conducted in an incomplete crossover design where one group of four goats was fed a mixed ration of barley grain (BRL), another group of four goats replaced barley grain with orange pulp (OP) and the last group of four goats with soybean hulls (SH). After adaptation to diets, the goats were allocated to individual metabolism cages and intake, faeces, urine and milk were recorded and analysed. Then, gas exchange measurements were recorded by a mobile open-circuit indirect calorimetry system using a head box. Dry matter intake was similar for all three groups (2.03 kg/d, on average). No influence of the diet was observed for energy balance and the efficiency of use of metabolizable energy for milk production was 0.61. The OP and SH diets showed greater (P < 0.05) fat mobilization (-42.8 kJ/kg of BW0.75, on average) than BRL (19.2 kJ/kg of BW0.75). Pentadecanoic acid (15:0) and heptadecanoic acid (17:0) were potential biomarkers of rumen function because the higher contents found in the milk of OP and SH goats than BRL suggest a negative impact of these diets on rumen bacterial metabolism; probably linked to the lower nitrogen supply of diet OP to synthesize microbial protein and greater content of fat in diet SH. Replacement of cereal grain with fibrous by-products did not increased enteric methane emissions (54.7 L/goat per day, on average). Therefore, lactating goats could utilize dry orange pulp and soybean hulls diets with no detrimental effect on milk performance.


Assuntos
Ração Animal/análise , Dieta/veterinária , Cabras/fisiologia , Lactação , Metano/metabolismo , Fenômenos Fisiológicos da Nutrição Animal , Animais , Carbono/metabolismo , Citrus sinensis/metabolismo , Metabolismo Energético , Ácidos Graxos/metabolismo , Feminino , Fermentação , Cabras/sangue , Cabras/urina , Hordeum/metabolismo , Leite/metabolismo , Nitrogênio/metabolismo , Oxirredução , Rúmen/fisiologia , Glycine max/metabolismo
7.
BMC Plant Biol ; 15: 197, 2015 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-26269119

RESUMO

BACKGROUND: Perception and transduction of temperature changes result in altered growth enabling plants to adapt to increased ambient temperature. While PHYTOCHROME-INTERACTING FACTOR4 (PIF4) has been identified as a major ambient temperature signaling hub, its upstream regulation seems complex and is poorly understood. Here, we exploited natural variation for thermo-responsive growth in Arabidopsis thaliana using quantitative trait locus (QTL) analysis. RESULTS: We identified GIRAFFE2.1, a major QTL explaining ~18 % of the phenotypic variation for temperature-induced hypocotyl elongation in the Bay-0 x Sha recombinant inbred line population. Transgenic complementation demonstrated that allelic variation in the circadian clock regulator EARLY FLOWERING3 (ELF3) is underlying this QTL. The source of variation could be allocated to a single nucleotide polymorphism in the ELF3 coding region, resulting in differential expression of PIF4 and its target genes, likely causing the observed natural variation in thermo-responsive growth. CONCLUSIONS: In combination with other recent studies, this work establishes the role of ELF3 in the ambient temperature signaling network. Natural variation of ELF3-mediated gating of PIF4 expression during nightly growing periods seems to be affected by a coding sequence quantitative trait nucleotide that confers a selective advantage in certain environments. In addition, natural ELF3 alleles seem to differentially integrate temperature and photoperiod information to induce architectural changes. Thus, ELF3 emerges as an essential coordinator of growth and development in response to diverse environmental cues and implicates ELF3 as an important target of adaptation.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Regulação da Expressão Gênica de Plantas , Transdução de Sinais , Fatores de Transcrição/genética , Adaptação Fisiológica , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Fotoperíodo , Locos de Características Quantitativas , Fatores de Transcrição/metabolismo
8.
Cell Rep ; 9(6): 1983-9, 2014 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-25533339

RESUMO

Developmental plasticity enables plants to respond to elevated ambient temperatures by adapting their shoot architecture. On the cellular level, the basic-helix-loop-helix (bHLH) transcription factor phytochrome interacting factor 4 (PIF4) coordinates this response by activating hormonal modules that in turn regulate growth. In addition to an unknown temperature-sensing mechanism, it is currently not understood how temperature regulates PIF4 activity. Using a forward genetic approach in Arabidopsis thaliana, we present extensive genetic evidence demonstrating that the de-etiolated 1 (DET1)-constitutive photomorphogenic 1 (COP1)-elongated hypocotyl 5 (HY5)-dependent photomorphogenesis pathway transcriptionally regulates PIF4 to coordinate seedling growth in response to elevated temperature. Our findings demonstrate that two of the most prevalent environmental cues, light and temperature, share a much larger set of signaling components than previously assumed. Similar to the toolbox concept in animal embryonic patterning, multipurpose signaling modules might have evolved in plants to translate various environmental stimuli into adaptational growth processes.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Estiolamento , Proteínas Nucleares/metabolismo , Organogênese Vegetal , Transdução de Sinais , Ubiquitina-Proteína Ligases/metabolismo , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/fisiologia , Proteínas de Arabidopsis/genética , Fatores de Transcrição de Zíper de Leucina Básica/genética , Regulação da Expressão Gênica de Plantas , Peptídeos e Proteínas de Sinalização Intracelular , Proteínas Nucleares/genética , Ubiquitina-Proteína Ligases/genética
9.
Plant J ; 80(6): 1057-71, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25330042

RESUMO

Membrane-delimited events play a crucial role for ABA signaling and PYR/PYL/RCAR ABA receptors, clade A PP2Cs and SnRK2/CPK kinases modulate the activity of different plasma membrane components involved in ABA action. Therefore, the turnover of PYR/PYL/RCARs in the proximity of plasma membrane might be a step that affects receptor function and downstream signaling. In this study we describe a single-subunit RING-type E3 ubiquitin ligase RSL1 that interacts with the PYL4 and PYR1 ABA receptors at the plasma membrane. Overexpression of RSL1 reduces ABA sensitivity and rsl1 RNAi lines that impair expression of several members of the RSL1/RFA gene family show enhanced sensitivity to ABA. RSL1 bears a C-terminal transmembrane domain that targets the E3 ligase to plasma membrane. Accordingly, bimolecular fluorescent complementation (BiFC) studies showed the RSL1-PYL4 and RSL1-PYR1 interaction is localized to plasma membrane. RSL1 promoted PYL4 and PYR1 degradation in vivo and mediated in vitro ubiquitylation of the receptors. Taken together, these results suggest ubiquitylation of ABA receptors at plasma membrane is a process that might affect their function via effect on their half-life, protein interactions or trafficking.


Assuntos
Ácido Abscísico/metabolismo , Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimologia , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Receptores de Superfície Celular/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Arabidopsis/genética , Arabidopsis/fisiologia , Proteínas de Arabidopsis/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Membrana Celular/metabolismo , Regulação da Expressão Gênica de Plantas , Meia-Vida , Proteínas de Membrana Transportadoras/genética , Receptores de Superfície Celular/genética , Transdução de Sinais , Ubiquitina-Proteína Ligases/genética , Ubiquitinação
10.
Plant Sci ; 215-216: 110-6, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24388521

RESUMO

Seed longevity is important to preserve crops and wild plants and it is limited by progressive cellular damage (aging) during storage. The induction of cellular stress defenses and the formation of the seed coat are crucial protecting events during seed development, a process mediated in Arabidopsis thaliana by the transcription factors LEC1, LEC2, FUS3 and the abscisic acid-activated ABI3. In order to identify novel determinants of seed longevity we have screened an activation-tagging mutant collection of Arabidopsis and isolated a dominant mutant with increased seed longevity under both natural and accelerated aging conditions. Molecular characterization indicates that the mutant phenotype is caused by over-expression of the At2g26130 gene encoding a RING-type zinc finger putative ubiquitin ligase. Loss of function of this gene in a T-DNA insertion mutant resulted in decreased seed longevity. We named this important gene for seed longevity RSL1 (from Ring finger of Seed Longevity1) and we could demonstrate ubiquitin ligase activity with the recombinant protein. Morphological alterations in shoot tissues of the RSL1 over-expressing plants and analysis of gibberellins levels suggest that RSL1 may increase gibberellins responses by some unknown mechanism. These results validate the forward genetic approach to seed longevity and anticipate the identification of many novel determinants of this important trait.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Senescência Celular/genética , Genes de Plantas , Domínios RING Finger/genética , Sementes/fisiologia , Ubiquitina-Proteína Ligases/genética , Ubiquitina/genética , Ácido Abscísico/metabolismo , Arabidopsis/enzimologia , Arabidopsis/fisiologia , Proteínas de Arabidopsis/metabolismo , DNA Bacteriano , Expressão Gênica , Giberelinas/genética , Giberelinas/metabolismo , Humanos , Longevidade , Mutagênese Insercional , Fenótipo , Brotos de Planta/metabolismo , Sementes/enzimologia , Sementes/metabolismo , Estresse Fisiológico/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Ubiquitina/metabolismo , Ubiquitina-Proteína Ligases/metabolismo
11.
Zootaxa ; 3640: 373-94, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-26000423

RESUMO

Specimens stored in museum collections represent a crucial source of morphological and genetic information, notably for taxonomically problematic groups and extinct taxa. Although fluid-preserved specimens of groups such as teleosts may constitute an almost infinite source of DNA, few ancient DNA protocols have been applied to such material. In this study, we describe a non-invasive Guanidine-based (GuSCN) ancient DNA extraction protocol adapted to fluid-preserved specimens that we use to re-assess the systematics of the genus Orestias (Cyprinodontidae: Teleostei). The latter regroups pupfishes endemic to the inter-Andean basin that have been considered as a 'species flock', and for which the morphology-based taxonomic delimitations have been hotly debated. We extracted DNA from the type specimens of Orestias kept at the Muséum National d'Histoire Naturelle of Paris, France, including the extinct species O. cuvieri. We then built the first molecular (control region [CR] and rhodopsin [RH]) phylogeny including historical and recently collected representatives of all the Orestias complexes as recognized by Parenti (1984a): agassizii, cuvieri, gilsoni and mulleri. Our ancient DNA extraction protocol was validated after PCR amplification through an approach based on fragment-by-fragment chimera detection. After optimization, we were able to amplify < 200 bp fragments from both mitochondrial and nuclear DNA (CR and RH, respectively) from probably formalin-fixed type specimens bathed entirely in the extraction fluid. Most of the individuals exhibited few modifications of their external structures after GuSCN bath. Our approach combining type material and 'fresh' specimens allowed us to taxonomically delineate four clades recovered from the well-resolved CR tree into four redefined complexes: agassizii (sensu stricto, i.e. excluding luteus-like species), luteus, cuvieri and gilsoni. The mulleri complex is polyphyletic. Our phylogenetic analyses based on both mitochondrial and nuclear DNA revealed a main, deep dichotomy within the genus Orestias, separating the agassizii complex from a clade grouped under shallow dichotomies as (luteus, (cuvieri, gilsoni)). This 'deep and shallow' diversification pattern could fit within a scenario of ancient divergence between the agassizii complex and the rest of Orestias, followed by a recent diversification or adaptive radiation within each complex during the Pleistocene, in- and outside the Lake Titicaca. We could not recover the reciprocal monophyly of any of the 15 species or morphotypes that were considered in our analyses, possibly due to incomplete lineage sorting and/or hybridization events. As a consequence, our results starkly question the delineation of a series of diagnostic characters listed in the literature for Orestias. Although not included in our phylogenetic analysis, the syntype of O. jussiei could not be assigned to the agassizii complex as newly defined. The CR sequence of the extinct O. cuvieri was recovered within the cuvieri clade (same haplotype as one representative of O. pentlandii), so the mtDNA of the former species might still be represented in the wild.


Assuntos
DNA/genética , Peixes Listrados/classificação , Peixes Listrados/genética , Estruturas Animais/anatomia & histologia , Animais , Evolução Molecular , Feminino , Peixes Listrados/anatomia & histologia , Masculino , Museus , Filogenia , Preservação Biológica
12.
Rev. Soc. Venez. Microbiol ; 29(2): 122-127, dic. 2009. ilus, tab
Artigo em Espanhol | LILACS | ID: lil-631663

RESUMO

Para determinar la prevalencia de Entamoeba gingivalis y Trichomonas tenax en cavidad bucal, se analizaron 50 muestras de la cavidad bucal de individuos de ambos géneros que acudieron a la Clínica Integral del Adulto de la Facultad de Odontología de la Universidad del Zulia. Se dividieron en dos grupos, de 25 individuos cada uno. Grupo 1, con manifestaciones clínicas de enfermedad (enfermedad periodontal y/o caries dental) al cual se le tomaron muestras de caries dental, placa y cálculo dental y grupo 2 o control con cavidad bucal sin manifestaciones clínicas de enfermedad, al cual se le tomó muestras de saliva y placa dental. Las muestras fueron analizadas microscópicamente a través del examen directo y con coloración permanente de hematoxilina férrica. Se observó una prevalencia de protozoarios bucales de un 10%; la especie predominante fue Entamoeba gingivalis en 5 casos, seguida de Trichomonas tenax en 1 caso. El estrato de 20 a 39 años fue el más afectado con un 10% de los casos. Al realizar el análisis estadístico resultó significativo (p=0,011) para las variables parasitismo y cavidad bucal enferma. El presente estudio pone de manifiesto una baja prevalencia de los protozoarios bucales en la población estudiada.


Fifty samples from the oral cavity of individuals of both genders who attended the Integral Adult Clinic of the Faculty of Odontology of Universidad del Zulia were analyzed to determine Entamoeba gingivalis and Trichomonas tenax prevalence. The patients were divided into two groups of 25 individuals each: Group 1, with clinical disease manifestations (periodontal disease and/or dental caries) from which we took samples from dental caries, plaque and dental calculus; and Group 2 or control, who had no clinical disease manifestations, from which we took saliva and dental plaque samples. All samples were analyzed microscopically through direct examination and with a ferric hematoxilin stain. There was a 10% prevalence of oral protozoa; the predominant species was Entamoeba gingivalis in 5 cases followed by Trichomonas tenax in 1 case. The 20-39 years age group was the most affected with 10% of cases. The statistical analysis was significant (p=0.011) for the parasitism and diseased oral cavity variables. The present study shows a low prevalence of oral cavity protozoa in the population studied.

13.
C R Biol ; 330(3): 255-64, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17434120

RESUMO

Productivity (trophic energy) is one of the most important factors promoting variation in species richness. A variety of species-energy relationships have been reported, including monotonically positive, monotonically negative, or unimodal (i.e. hump-shaped). The exact form of the relationship seems to depend, among other things, on the spatial scale involved. However, the mechanisms behind these patterns are still largely unresolved, although many hypotheses have been suggested. Here we report a case of local-scale positive species-energy relationship. Using 14 local fish assemblages in tropical forested headwater streams (Bolivia), and after controlling for major local abiotic factors usually acting on assemblage richness and structure, we show that rising energy availability through leaf litter decomposition rates allows trophically specialized species to maintain viable populations and thereby to increase assemblage species richness. By deriving predictions from three popular mechanistic explanations, i.e. the 'increased population size', the 'consumer pressure', and the 'specialization' hypotheses, our data provide only equivocal support for the latter.


Assuntos
Ecossistema , Peixes/fisiologia , Animais , Bolívia , Peixes/classificação , Peixes/genética , Água Doce , Variação Genética , Folhas de Planta/fisiologia , Densidade Demográfica , Comportamento Predatório , Estações do Ano
14.
Cienc. odontol ; 3(1): 31-37, ene.-jun. 2006. ilus
Artigo em Espanhol | LILACS | ID: lil-499943

RESUMO

Existen procedimientos quirúrgicos y no quirúrgicos que mantienen los tejidos blandos durante la oseointegración y la confección de las restauraciones. Este artículo describe un abordaje pre-prostético empleado para la preservación de la arquitectura gingival alrededor de un implante dental colocado inmediatamente después de la extracción del incisivo lateral maxilar derecho. Realizado el examen clínico y radiográfico, se diagnosticó una reabsorción dentinaria externa, por lo que se planificó la extracción y colocación de implante; la corana fue preparada para la elaboración del puente adhesivo provisional. Completada la oseointegración, se realizó el destape quirúrgico del implante con una técnica de ojal y colocación del tornillo de cicatrización. Posteriormente, se tomó la impresión definitiva y tres semanas después, se insertó la corona de metal-porcelana. Al cabo de dos semanas, se evaluó la presencia de las papilas interdentales y se sondeó para verificar la presencia o no de bolsillo. Posteriormente se evaluó a los 6, 12 y 24 meses y se encontraron similares características, medidas de sondeo y de llenado de la papila. El uso de prótesis adhesivas con póntico ovoide durante la oseointegración y el manejo de técnicas quirúrgicas no invasivas en el destape del implante permitieron conservar la arquitectura gingival, por lo que se alcanzaron los objetivos estéticos de la restauración.


Assuntos
Humanos , Masculino , Feminino , Prótese Parcial Fixa/efeitos adversos , Prótese Parcial Fixa , Implantes Dentários/efeitos adversos , Implantes Dentários , Odontologia , Venezuela
15.
Braz. arch. biol. technol ; 48(1): 91-108, Jan. 2005. tab, graf
Artigo em Inglês | LILACS | ID: lil-398316

RESUMO

A água dos rios constituem um recurso básico para a humanidade. Instrumentos biológicos eficaces (com fundamento ecológico, eficientes, rápidos e aplicáveis à regiões ecologicamente diferentes) são necessários para medir a "saúde" destes. Adaptar tais instrumentos a uma grande área geográfica requer uma compreensão detalhada dos padrões da composição da assembléia de organismos e da sua distribuição dentro e entre os corpos da água em condições naturais, e da natureza dos principais gradientes ambientais que causam ou explicam estes padrões. Uma revisão da literatura disponível pode ajudar a identificar os fatores ambientais mais consistentes que estruturam a assembléia de peixes de ambientes lóticos em condições naturais.

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