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AbstractAnticipatory changes in organismal responses, triggered by reliable environmental cues for future conditions, are key to species' persistence in temporally variable environments. Such responses were tested by measuring the physiological performance of a tropical high-shore oyster in tandem with the temporal predictability of environmental temperature. Heart rate of the oyster increased with environmental temperatures until body temperature reached â¼37°C, when a substantial depression occurred (â¼60%) before recovery between â¼42° and 47°C, after which cardiac function collapsed. The sequential increase, depression, and recovery in cardiac performance aligned with temporal patterns in rock surface temperatures, where the risk of reaching temperatures close to the oysters' lethal limit accelerates if the rock heats up beyond â¼37°C, coinciding closely with the body temperature at which the oysters initiate metabolic depression. The increase in body temperature over a critical threshold serves as an early-warning cue to initiate anticipatory shifts in physiology and energy conservation before severe thermal stress occurs on the shore. Cross-correlating the onset of physiological mechanisms and temporal structures in environmental temperatures, therefore, reveals the potential role of reliable real-time environmental cues for future conditions in driving the evolution of anticipatory responses.
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Frecuencia Cardíaca , Calor , Ostreidae/metabolismo , Animales , Corazón/fisiopatología , Ostreidae/fisiologíaRESUMEN
Although thermal performance is widely recognised to be pivotal in determining species' distributions, assessment of this performance is often based on laboratory-acclimated individuals, neglecting their proximate thermal history. The thermal history of a species sums the evolutionary history and, importantly, the thermal events recently experienced by individuals, including short-term acclimation to environmental variations. Thermal history is perhaps of greatest importance for species inhabiting thermally challenging environments and therefore assumed to be living close to their thermal limits, such as in the tropics. To test the importance of thermal history, the responses of the tropical oyster Isognomon nucleus to short-term differences in thermal environments were investigated. Critical and lethal temperatures and oxygen consumption were improved in oysters that previously experienced elevated air temperatures, and were associated with an enhanced heat shock response, indicating that recent thermal history affects physiological performance as well as inducing short-term acclimation to acute conditions. These responses were, however, associated with trade-offs in feeding activity, with oysters that experienced elevated temperatures showing reduced energy gain. Recent thermal history, therefore, seems to rapidly invoke physiological mechanisms that enhance survival of short-term thermal challenge but also longer term climatic changes and consequently needs to be incorporated into assessments of species' thermal performances.
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Aclimatación , Calor , Ostreidae/fisiología , Animales , Ecosistema , Respuesta al Choque Térmico , Consumo de Oxígeno/fisiologíaRESUMEN
In the natural environment, organisms are exposed to large variations in physical conditions. Quantifying such physiological responses is, however, often performed in laboratory acclimation studies, in which usually only a single factor is varied. In contrast, field acclimatization may expose organisms to concurrent changes in several environmental variables. The interactions of these factors may have strong effects on organismal function. In particular, rare events that occur stochastically and have relatively short duration may have strong effects. The present experiments studied levels of expression of several genes associated with cellular stress and metabolic regulation in a field population of limpet Cellana toreuma that encountered a wide range of temperatures plus periodic rain events. Physiological responses to these variable conditions were quantified by measuring levels of mRNA of genes encoding heat-shock proteins (Hsps) and metabolic sensors (AMPKs and Sirtuin 1). Our results reveal high ratios of individuals in upregulation group of stress-related gene expression at high temperature and rainy days, indicating the occurrence of stress from both prevailing high summer temperatures and occasional rainfall during periods of emersion. At high temperature, stress due to exposure to rainfall may be more challenging than heat stress alone. The highly variable physiological performances of limpets in their natural habitats indicate the possible differences in capability for physiological regulation among individuals. Our results emphasize the importance of studies of field acclimatization in unravelling the effects of environmental change on organisms, notably in the context of multiple changes in abiotic factors that are accompanying global change.
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Gastrópodos/metabolismo , Lluvia , Estrés Fisiológico/genética , Temperatura , Proteínas Quinasas Activadas por AMP/genética , Animales , Clima , Gastrópodos/genética , Proteínas de Choque Térmico/genética , Dinámica Poblacional , Sirtuina 1/genéticaRESUMEN
Intertidal invertebrates develop effective physiological adaptations to cope with the rapidly changing thermal environment in the intertidal zone. In the present study, the temporal patterns of heart rate, protein carbonyl groups, and genes encoding heat shock proteins (hsp70 and hsp90) and metabolic sensors (ampkα, ampkß and sirt1) were measured to study the effect of sublethal heat stress on the cardiac function, oxidative stress, heat shock response and cellular metabolism of an intertidal limpet Cellana toreuma. All the physiological parameters are sensitive to temperature and duration of heat stress. Spearman correlation analysis revealed that the correlations between heart rate and levels of heat shock proteins mRNA and metabolic sensors mRNA were statistically significant. These results further suggest that cardiac function plays crucial roles in cellular energy metabolism and heat shock responses. The significant increase of protein carbonyl groups at 34°C after 4h exposure indicated that the failure of cardiac function and the increase of anaerobic metabolism partly leads to the increase of protein carbonyl groups. Generally, the physiological responses to heat stress are sensitive to temperature and are energy-consumptive, as indicated by the upregulation of metabolic sensors mRNA. However, the upregulation of heat shock proteins and metabolic sensors at the post-transcriptional level and related functions need to be confirmed in further experiments.
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Regulación de la Temperatura Corporal , Gastrópodos/fisiología , Frecuencia Cardíaca , Respuesta al Choque Térmico , Animales , Gastrópodos/genética , Gastrópodos/metabolismo , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismoRESUMEN
The Mediterranean mussel, Mytilus galloprovincialis, is a significant marine bivalve species that has ecological and economic importance. This species is robustly resilient and highly invasive. Despite the scientific and commercial interest in studying its biology and aquaculture, there remains a need for a high-quality, chromosome-scale reference genome. In this study, we have assembled a high-quality chromosome-scale reference genome for M. galloprovincialis. The total length of our reference genome is 1.41 Gb, with a scaffold N50 sequence length of 96.9 Mb. BUSCO analysis revealed a 97.5% completeness based on complete BUSCOs. Compared to the four other available M. galloprovincialis assemblies, the assembly described here is dramatically improved in both contiguity and completeness. This new reference genome will greatly contribute to a deeper understanding of the resilience and invasiveness of M. galloprovincialis.
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Cromosomas , Genoma , Mytilus , Mytilus/genética , AnimalesRESUMEN
The effects of heat stress on organisms are manifested at the levels of organ function, metabolic activity, protein stability and gene expression. Here, we examined effects of high temperature on the intertidal limpet Cellana toreuma to determine how the temperatures at which (1) organ failure (cardiac function), (2) irreversible protein damage (carbonylation) and (3) expression of genes encoding proteins involved in molecular chaperoning (hsp70 and hsp90) and metabolic regulation (ampk and sirt1) occur compare with field temperatures, which commonly exceed 30°C and can reach 46°C. Heart failure, indexed by the Arrhenius break temperature, occurred at 34.3°C. Protein carbonylation rose significantly at 38°C. Genes for heat shock proteins HSP70 (hsp70) and HSP90 (hsp90), for two subunits of AMP-activated protein kinase (AMPK) (ampkα and ampkß) and for histone/protein deacetylase SIRT1 (sirt1) all showed increased expression at 30°C. Temperatures of maximal expression differed among genes, as did temperatures at which upregulation ceased. Expression patterns for ampk and sirt1 indicate that heat stress influenced cellular energy homeostasis; above ~30°C, upregulation of ATP-generating pathways is suggested by elevated expression of genes for ampk; an altered balance between reliance on carbohydrate and lipid fuels is indicated by changes in expression of sirt1. These results show that C. toreuma commonly experiences temperatures that induce expression of genes associated with the stress response (hsp70 and hsp90) and regulation of energy metabolism (ampk and sirt1). At high temperatures, there is likely to be a shift away from anabolic processes such as growth to catabolic processes, to provide energy for coping with stress-induced damage, notably to proteins.
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Proteínas Quinasas Activadas por AMP/genética , Proteínas de Choque Térmico/genética , Sirtuina 1/genética , Caracoles/genética , Proteínas Quinasas Activadas por AMP/metabolismo , Animales , China , Clonación Molecular , ADN Complementario/genética , ADN Complementario/metabolismo , Regulación de la Expresión Génica , Marcadores Genéticos , Corazón/fisiología , Proteínas de Choque Térmico/metabolismo , Calor , Datos de Secuencia Molecular , Estrés Oxidativo , Carbonilación Proteica , ARN Mensajero/genética , ARN Mensajero/metabolismo , Análisis de Secuencia de ADN , Sirtuina 1/metabolismo , Caracoles/metabolismoRESUMEN
Osteosarcoma (OS) is one of the most common malignant neoplasms in children and adolescents. Immune infiltration into the microenvironment of the tumor has a positive correlation with overall survival in patients with OS. The purpose of this study was to search for potential diagnostic markers that are involved in immune cell infiltration for OS. Patients with OS who acquired metastases within 5 years (n = 34) were compared to patients who did not develop metastases within 5 years (n = 19). Differentially expressed genes (DEGs) were tested for in both patient groups. To discover possible biomarkers, the LASSO regression model and the SVM-RFE analysis were both carried out. With the assistance of CIBERSORT, the compositional patterns of the 22 different types of immune cell fraction in OS were estimated. In this research, a total of 33 DEGs were obtained: 33 genes were significantly downregulated. Moreover, we identified six critical genes, including ALOX5AP, HLA-DOA, HLA-DMA, HLA-DRB4, HCLS1 and LOC647450. ROC assays confirmed their diagnostic value with AUC > 0.7. In addition, we found that the six critical genes were associated with immune infiltration. Then, we confirmed the expression of ALOX5AP was distinctly decreased in OS specimens and cell lines. High expression of ALOX5AP predicted an advanced clinical stage and overall survival of OS patients. Functionally, we found that overexpression of ALOX5AP distinctly suppressed the proliferation, migration, invasion and EMT via modulating Wnt/ß-catenin signaling. Overall, we found that ALOX5AP overexpression inhibits OS development via regulation of Wnt/ß-catenin signaling pathways, suggesting ALOX5AP as a novel molecular biomarker for enhanced therapy of OS.
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Neoplasias Óseas , Osteosarcoma , Adolescente , Niño , Humanos , beta Catenina/genética , beta Catenina/metabolismo , Línea Celular Tumoral , Movimiento Celular/genética , Neoplasias Óseas/patología , Pronóstico , Osteosarcoma/patología , Proliferación Celular/genética , Regulación Neoplásica de la Expresión Génica/genética , Microambiente Tumoral/genética , Proteínas Activadoras de la 5-Lipooxigenasa/genética , Proteínas Activadoras de la 5-Lipooxigenasa/metabolismoRESUMEN
The roles of synonymous mutations for adapting to stressful thermal environments are of fundamental biological and ecological interests but poorly understood. To study whether synonymous mutations influence thermal adaptation at specific microhabitats, a genome-wide genotype-phenotype association analysis is carried out in the black mussels Mytilisepta virgata. A synonymous mutation of Ubiquitin-specific Peptidase 15 (MvUSP15) is significantly associated with the physiological upper thermal limit. The individuals carrying GG genotype (the G-type) at the mutant locus possess significantly lower heat tolerance compared to the individuals carrying GA and AA genotypes (the A-type). When heated to sublethal temperature, the G-type exhibit higher inter-individual variations in MvUSP15 expression, especially for the mussels on the sun-exposed microhabitats. Taken together, a synonymous mutation in MvUSP15 can affect the gene expression profile and interact with microhabitat heterogeneity to influence thermal resistance. This integrative study sheds light on the ecological importance of adaptive synonymous mutations as an underappreciated genetic buffer against heat stress and emphasizes the importance of integrative studies at a microhabitat scale for evaluating and predicting the impacts of climate change.
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Bivalvos , Termotolerancia , Animales , Mutación Silenciosa , Bivalvos/genética , Aclimatación/genética , Termotolerancia/genética , TemperaturaRESUMEN
Elucidating the physiological mechanisms that underlie thermal stress and discovering how species differ in capacities for phenotypic acclimatization and evolutionary adaptation to this stress is critical for understanding current latitudinal and vertical distribution patterns of species and for predicting their future state in a warming world. Such mechanistic analyses require careful choice of study systems (species and temperature-sensitive traits) and design of laboratory experiments that reflect the complexities of in situ conditions. Here, we critically review a wide range of studies of intertidal molluscs that provide mechanistic accounts of thermal effects across all levels of biological organization - behavioural, organismal, organ level, cellular, molecular, and genomic - and show how temperature-sensitive traits govern distribution patterns and capacities for coping with thermal stress. Comparisons of congeners from different thermal habitats are especially effective means for identifying adaptive variation. We employ these mechanistic analyses to illustrate how species differ in the severity of threats posed by rising temperature. Counterintuitively, we show that some of the most heat-tolerant species may be most threatened by increases in temperatures because of their small thermal safety margins and minimal abilities to acclimatize to higher temperatures. We discuss recent molecular biological and genomic studies that provide critical foundations for understanding the types of evolutionary changes in protein structure, RNA secondary structure, genome content, and gene expression capacities that underlie adaptation to temperature. Duplication of stress-related genes, as found in heat-tolerant molluscs, may provide enhanced capacity for coping with higher temperatures. We propose that the anatomical, behavioural, physiological, and genomic diversity found among intertidal molluscs, which commonly are of critical importance and high abundance in these ecosystems, makes this group of animals a highly appropriate study system for addressing questions about the mechanistic determinants of current and future distribution patterns of intertidal organisms.
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Aclimatación , Ecosistema , Adaptación Fisiológica , Animales , Cambio Climático , Moluscos , TemperaturaRESUMEN
Root zone microbial structure is particularly complex in plants with rhizosheaths, and greater understanding of the rhizosheath may play an important role in the future development of sustainable agricultural practices. However, one important reason to focus study on rhizosheath microbial structure is that there is no definite method for rhizosheath separation. The aim of this study was to explore rhizosheath isolation methods and the diversity characteristics of microorganisms around the rhizosphere. In this study, we isolated the rhizosheath of Stipa grandis, a dominant species in desert steppe, and the microorganisms in the roots, root epidermis, rhizosheath and rhizosphere soil were extracted and sequenced by 16S rRNA and ITS. The alpha diversity index of bacteria in Stipa grandis rhizosphere soil was the greatest, followed by rhizosheath, and the alpha diversity index of endophytic bacteria in root system was the smallest. The alpha diversity index of fungi in the rhizosheath and rhizosphere soil were significantly higher than that in the root epidermis and root system. There were significant differences in bacterial community structure between the root epidermis, endophytic bacteria, rhizosheath and rhizosphere soil. Unlike bacterial community structure, the community structure of fungi in the root epidermis was similar that of endophytic fungi, but significantly different from those in rhizosheath and rhizosphere soil. This study demonstrated a feasible method for separating plant rhizosheath and root epidermis. We suggest that the root epidermis can act as the interface between the host plant root and the external soil environment. We will have to re-examine the biological and ecological significance of rhizosheath and microorganisms in rhizosheath, as well as the mechanism explaining the close relationship of the rhizosheath and the plant root epidermis. This study provides theoretical and technical guidance for the isolation of the plant rhizosheath and the study of microorganisms in plant rhizosheath.
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Microbiota/genética , Raíces de Plantas/microbiología , Poaceae/microbiología , Bacterias/genética , Hongos/genética , ARN Ribosómico 16S , Rizosfera , Suelo , Microbiología del SueloRESUMEN
OBJECTIVE: MiR-1224 has been reported to exhibit abnormal expression in several tumors. However, the expressing pattern and roles of miR-1224 in gastric cancer (GC) remain unclear. Our current research aimed to explore the potential involvement of miR-1224 in the GC progression. MATERIALS AND METHODS: The expression of miR-1224 was examined in tissue samples of 128 GC patients and cell lines by RT-PCR. Besides, the associations of miR-1224 expressions with clinicopathologic features and prognosis of GC patients were analyzed. Then, the possible influences of miR-1224 on cell proliferation and cell migration were determined. Afterward, the molecular target of miR-1224 was identified using bioinformatics assays and confirmed experimentally. Finally, RT-PCR and Western blot assays were performed to investigate the effect of the abnormal miR-1224 expression on the EMT and Wnt/ß-catenin pathway. RESULTS: miR-1224 was lowly expressed in the GC specimens and cell lines due to T classification and TNM stage. Survival assays demonstrated that GC patients with low expressions of miR-1224 possessed poor overall survivals. Moreover, in vitro and in vivo assays revealed that the overexpression of miR-1224 inhibited cell proliferation, migration, and invasion in GC cells. SATB homeobox 1 (SATB1) was verified as a direct target of miR-1224 in GC. Furthermore, ß-catenin and c-myc were significantly inhibited in miR-1224-overexpression cells. CONCLUSIONS: Our findings highlight the potential of miR-1224 as a therapeutic target and novel biomarker for GC patients.
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Populations at the edge of their species' distribution ranges are typically living at the physiological extreme of the environmental conditions they can tolerate. As a species' response to global change is likely to be largely determined by its physiological performance, subsequent changes in environmental conditions can profoundly influence populations at range edges, resulting in range extensions or retractions. To understand the differential physiological performance among populations at their distribution range edge and center, we measured levels of mRNA for heat shock protein 70 (hsp70) as an indicator of temperature sensitivity in two high-shore littorinid snails, Echinolittorina malaccana and E. radiata, between 1°N to 36°N along the NW Pacific coast. These Echinolittorina snails are extremely heat-tolerant and frequently experience environmental temperatures in excess of 55⯰C when emersed. It was assumed that animals exhibiting high temperature sensitivity will synthesize higher levels of mRNA, which will thus lead to higher energetic costs for thermal defense. Populations showed significant geographic variation in temperature sensitivity along their range. Snails at the northern range edge of E. malaccana and southern range edge of E. radiata exhibited higher levels of hsp70 expression than individuals collected from populations at the center of their respective ranges. The high levels of hsp70 mRNA in populations at the edge of a species' distribution range may serve as an adaptive response to locally stressful thermal environments, suggesting populations at the edge of their distribution range are potentially more sensitive to future global warming.
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Calentamiento Global , Respuesta al Choque Térmico/fisiología , Caracoles/fisiología , Animales , Monitoreo del Ambiente , Proteínas HSP70 de Choque Térmico , Calor , TemperaturaRESUMEN
Patients with Her2-positive breast cancer exhibit de novo resistance or develop acquired resistance in less than one year after Her2 targeting treatment, but the mechanism is not fully elucidated. Compensatory pathways such as the IGF-1R/IRS-1 pathway, are activated, leading to aberrant enhanced PI3K/Akt/mTOR pathway activity to attenuate the efficacy of trastuzumab. Cullin7 could participate in the degradation of IRS-1 in a mTOR/S6K dependent manner. Whether Cullin7 participates in trastuzumab resistance needs to be further investigated. Here, we reveals that Cullin7 is overexpressed in trastuzumab-resistant Her2 positive breast cancer cells. Knockdown of Cullin7 reduces degradation of Ser phosphorylation of IRS-1, attenuates activation of the PI3K/AKT pathway, and partly restores trastuzumab sensitivity in trastuzumab-resistant Her2 positive breast cancer cells. IGFBP-3 expression is decreased in trastuzumab-resistant Her2 positive breast cancer cells, which leads to release of the Wnt signaling pathway inhibition and an increase in Cullin7 expression, as mediated by TCF7L2. Overexpression of Cullin7 in Her2-amplified breast cancer tissues has clinical implications because it positively correlates with shorter disease-free survival (DFS) and inadequate response to trastuzumab. Thus, our results suggest a critical role for Cullin7 in response to trastuzumab, which has significant implications for selection of the optimal therapeutic strategy for Her2 positive breast cancers.
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Neoplasias de la Mama/patología , Proteínas Cullin/genética , Resistencia a Antineoplásicos , Proteínas Sustrato del Receptor de Insulina/metabolismo , Proteína 3 de Unión a Factor de Crecimiento Similar a la Insulina/genética , Receptor ErbB-2/genética , Animales , Neoplasias de la Mama/genética , Línea Celular Tumoral , Supervivencia Celular , Regulación hacia Abajo , Femenino , Amplificación de Genes , Humanos , Proteínas Sustrato del Receptor de Insulina/química , Ratones , Trasplante de Neoplasias , Fosfatidilinositol 3-Quinasas/metabolismo , Proteolisis , Proteínas Proto-Oncogénicas c-akt/metabolismo , TrastuzumabRESUMEN
OBJECTIVE: To analyze the epidemiologic characteristics of TCM syndrome distribution and season correlation in hypertension patients. METHODS: Clinical materials regarding population, symptoms and signs, etc. of 698 hypertension patients were collected, and statistical analysis on them was conducted. RESULTS: TCM syndrome type revealed in patients, in order of frequency from high to low, were: Gan-fire flaming-up syndrome, yin-deficiency and yang-excess syndrome, phlegm-dampness accumulation syndrome, both yin-yang deficiency syndrome, and others. The incidence of various syndromes was higher in the winter/spring and rather low in the summer, and Gan-fire flaming-up syndrome was positively related to the spring and negative to the summer. CONCLUSIONS: The syndrome types of hypertension patients are chiefly the Gan-fire flaming-up syndrome, yin-deficiency and yang-excess syndrome, phlegm-dampness accumulation syndrome, and both yin-yang deficiency syndrome; Gan-fire flaming-up syndrome is the dominance; their incidence is higher in the winter/spring and lower in the summer.
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Encuestas Epidemiológicas , Hipertensión/epidemiología , Medicina Tradicional China , Adolescente , Adulto , Anciano , China/epidemiología , Femenino , Humanos , Hipertensión/diagnóstico , Masculino , Persona de Mediana Edad , Estaciones del Año , Adulto JovenRESUMEN
Osteosarcoma is the most common and highly aggressive bone neoplasm often occurs among adolescents and young people. In despite of the major advances in the treatment, the overall survival of osteosarcoma patients remains poor. Long non-coding RNAs (lncRNAs) have been identified as key regulators involved in tumorigenesis and progression of osteosarcoma. However, the exact roles and mechanisms of lncRNAs in osteosarcoma remain unclear. In this study, the functions and underlying molecular mechanisms of a novel lncRNA, ITGB2 antisense RNA1 (ITGB2-AS1) were investigated in osteosarcoma. The expression levels of ITGB2-AS1 were up-regulated in osteosarcoma tissue samples and cell lines determined by qRT-PCR assay. Osteosarcoma patients with high ITGB2-AS1 expression had a significantly poor prognosis. In addition, knockdown of ITGB2-AS1 inhibited the proliferation and induced apoptosis of osteosarcoma cells using MTT assay and flow cytometry detection. Furthermore, wound healing and transwell invasion assay revealed that depletion of ITGB2-AS1 suppressed the migration and invasion abilities of osteosarcoma cells. Molecular mechanism study indicated that ITGB2-AS1 inhibition impaired Wnt/ß-catenin signalling pathway in osteosarcoma cells. Taken together, our study suggested that ITGB2-AS1 played critical roles in the development and progression of osteosarcoma via Wnt/ß-catenin signalling, indicating that ITGB2-AS1 might be a valuable diagnostic biomarker and potential anticancer therapeutic target for osteosarcoma.
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Neoplasias Óseas/metabolismo , Proliferación Celular , Proteínas de Neoplasias/metabolismo , Osteosarcoma/metabolismo , ARN sin Sentido/metabolismo , ARN Largo no Codificante/metabolismo , ARN Neoplásico/metabolismo , Vía de Señalización Wnt , beta Catenina/metabolismo , Anciano , Anciano de 80 o más Años , Neoplasias Óseas/mortalidad , Neoplasias Óseas/patología , Línea Celular Tumoral , Supervivencia sin Enfermedad , Femenino , Humanos , Masculino , Metástasis de la Neoplasia , Osteosarcoma/mortalidad , Osteosarcoma/patología , Tasa de SupervivenciaRESUMEN
In August 2010, a sampling work was conducted in the plots of the Leymus chinensis steppe, which were fenced in 1979, 1999, and 2004, respectively, in Inner Mongolia Grassland Ecosystem Research Station (IMGERS), aimed to approach the effects of different time periods of enclosure on the caloric values of main plant species, litters, and commnities, and on the total energy storage per unit area. Enclosure had significant effects on the caloric values of the main plant species, litters, and communities, and on the total energy storage per unit area. The total energy storage per unit area in the plots fenced in 1979 and 1999 was significantly higher than that in the plot fenced in 2004, while the caloric values of the litters and communities were in adverse. No significant differences were observed between the plots fenced in 1979 and 1999, respectively. The caloric value of the same plant species varied significantly with the time period of enclosure, and that of different plant species presently definite differences. The caloric value of communities depended on the plant species in the communities, while the total energy storage per unit area depended on the biomass production of the steppe. Both the caloric value of communities and the total energy storage per unit area presented the same variation trend of fluctuation in a short term, but maintained at a stable level over a long period of enclosure, and ecologically reached enrgy balance finally.
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Ecosistema , Metabolismo Energético , Poaceae/crecimiento & desarrollo , Calorimetría , China , Hojas de la Planta/metabolismo , Poaceae/clasificación , Poaceae/metabolismo , RíosRESUMEN
AIM: Genetic data were used to measure the phylogeographic distribution of the limpet, Cellana toreuma along the China coast in order to acsertain impacts of historic events, ocean currents and especially freshwater discharge from the Yangtze River on the connectivity of intertidal species with limited larval dispersal capability. METHODOLOGY/PRINCIPAL FINDINGS: Genetic variation in 15 populations of C. toreuma (nâ=â418), ranging from the Yellow Sea (YS), East China Sea (ECS) and South China Sea (SCS), were determined from partial mitochondrial cytochrome c oxidase subunit I gene. Genetic diversity and divergence based on haplotype frequencies were analyzed using CONTRIB, and AMOVA was used to examine genetic population structure. Historic demographic expansions were evaluated from both neutrality tests and mismatch distribution tests. Among the 30 haplotypes identified, a dominant haplotype No. 1 (H1) existed in all the populations, and a relatively abundant private haplotype (H2) in YS. Pairwise F(ST) values between YS and the other two groups were relatively high and the percentage of variation among groups was 10.9%. CONCLUSIONS: The high nucleotide and gene diversity in the YS, with large pairwise genetic distances and relatively high percentages of variation among groups, suggests that this group was relatively isolated from ECS and SCS. This is likely driven by historic events, ocean currents, and demographic expansion. We propose that freshwater discharge from the Yangtze River, which may act as physical barrier limiting the southward dispersal of larvae from northern populations, is especially important in determining the separation of the YS group from the rest of the Chinese populations of C. toreuma.
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Gastrópodos/clasificación , Animales , China , ADN Mitocondrial/genética , Demografía , Complejo IV de Transporte de Electrones/genética , Gastrópodos/genética , Frecuencia de los Genes , Genética de Población , Haplotipos , Océanos y Mares , Filogeografía , RíosRESUMEN
BACKGROUND: Methane (CH(4)) uptake by steppe soils is affected by a range of specific factors and is a complex process. Increased stocking rate promotes steppe degradation, with unclear consequences for gas exchanges. To assess the effects of grazing management on CH(4) uptake in desert steppes, we investigated soil-atmosphere CH(4) exchange during the winter-spring transition period. METHODOLOGY/MAIN FINDING: The experiment was conducted at twelve grazing plots denoting four treatments defined along a grazing gradient with three replications: non-grazing (0 sheep/ha, NG), light grazing (0.75 sheep/ha, LG), moderate grazing (1.50 sheep/ha, MG) and heavy grazing (2.25 sheep/ha, HG). Using an automatic cavity ring-down spectrophotometer, we measured CH(4) fluxes from March 1 to April 29 in 2010 and March 2 to April 27 in 2011. According to the status of soil freeze-thaw cycles (positive and negative soil temperatures occurred in alternation), the experiment was divided into periods I and II. Results indicate that mean CH(4) uptake in period I (7.51 µg CH(4)-C m(-2) h(-1)) was significantly lower than uptake in period II (83.07 µg CH(4)-C m(-2) h(-1)). Averaged over 2 years, CH(4) fluxes during the freeze-thaw period were -84.76 µg CH(4)-C m(-2) h(-1) (NG), -88.76 µg CH(4)-C m(-2) h(-1) (LG), -64.77 µg CH(4)-C m(-2) h(-1) (MG) and -28.80 µg CH(4)-C m(-2) h(-1) (HG). CONCLUSIONS/SIGNIFICANCE: CH(4) uptake activity is affected by freeze-thaw cycles and stocking rates. CH(4) uptake is correlated with the moisture content and temperature of soil. MG and HG decreases CH(4) uptake while LG exerts a considerable positive impact on CH(4) uptake during spring freeze-thaw cycles in the northern desert steppe in China.
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Ecosistema , Congelación , Metano/química , Suelo/química , Animales , China , Ovinos/fisiologíaRESUMEN
OBJECTIVE: To investigate the frequency of mitochondrial DNA (mtDNA) D-loop hypervariable region II (HVR II) and hypervariable region III (HVR III) mutations in oral squamous cell carcinoma (OSCC) and their correlation to provide the new targets for the prevention and treatment of OSCC. METHODS: The D-loop HVR II and HVR III regions of mtDNA in seven cases with OSCC tissues, matched with paracancerous tissues and normal mucosa tissues from the same case, were amplified by polymerase chain raction (PCR), then were detected by direct sequencing to find the mutantsites after the comparison of all sequencing results with the mtDNA Cambridge sequence in the GenBank database. RESULTS: 82 (56 species) nucleotide changes, with 51(26 species) nucleotide polymorphism, were found after the comparison of all sequencing results with the mtDNA Cambridge sequence in the GenBank database. 31(30 species) mutations, with 21 located within the HVR II and HVR III regions, were found in 3 tumor tissue samples, their paracancerous and normal mucosa tissue were found more polymorphic changes but no mutation. The mtDNA D-loop HVR II and HVR III regions mutation rate was 42.9% (3/7) in OSCC. CONCLUSION: The mtDNA D-loop HVR II and HVR III regions were highly polymorphic and mutable regions in OSCC. It suggested that the D-loop HVR II and HVR III regions of mtDNA might play a significant role in the tumorigenesis of OSCC. It may become new targets for the gene therapy of OSCC by regulating the above indexes.