RESUMEN
Transcription of eukaryotic protein-coding genes generates immature mRNAs that are subjected to a series of processing events, including capping, splicing, cleavage, and polyadenylation (CPA), and chemical modifications of bases. Alternative polyadenylation (APA) greatly contributes to mRNA diversity in the cell. By determining the length of the 3' untranslated region, APA generates transcripts with different regulatory elements, such as miRNA and RBP binding sites, which can influence mRNA stability, turnover, and translation. In the model plant Arabidopsis thaliana, APA is involved in the control of seed dormancy and flowering. In view of the physiological importance of APA in plants, we decided to investigate the effects of light/dark conditions and compare the underlying mechanisms to those elucidated for alternative splicing (AS). We found that light controls APA in approximately 30% of Arabidopsis genes. Similar to AS, the effect of light on APA requires functional chloroplasts, is not affected in mutants of the phytochrome and cryptochrome photoreceptor pathways, and is observed in roots only when the communication with the photosynthetic tissues is not interrupted. Furthermore, mitochondrial and TOR kinase activities are necessary for the effect of light. However, unlike AS, coupling with transcriptional elongation does not seem to be involved since light-dependent APA regulation is neither abolished in mutants of the TFIIS transcript elongation factor nor universally affected by chromatin relaxation caused by histone deacetylase inhibition. Instead, regulation seems to correlate with changes in the abundance of constitutive CPA factors, also mediated by the chloroplast.
Asunto(s)
Arabidopsis , Cloroplastos , Regulación de la Expresión Génica de las Plantas , Luz , Poliadenilación , Arabidopsis/genética , Arabidopsis/metabolismo , Cloroplastos/metabolismo , Cloroplastos/genética , Empalme Alternativo , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , ARN Mensajero/genética , ARN Mensajero/metabolismoRESUMEN
BACKGROUND: The genetic backgrounds and occurrence patterns of weedy rice (WR, Oryza sativa) are highly diverse, and so are the challenges facing its control among countries. WR control is difficult because it is similar to cultivated rice and manual removal is one of the few options for control. Understanding the ecology of WR will aid efforts to break its life cycle and establish long-term management strategies under both irrigated and rainfed systems. RESULTS: Nicaraguan WR (NWR) plants were genetically closer to the AUS and Indica pools in terms of to genetic distance. A map of admixture coefficients suggested a pattern of long-distance dispersal and spread of NWR across Nicaragua, which has likely been facilitated by commercial activities and sharing of harvesting equipment between border cities or important trading ports and inland regions. Moreover, the NWR plants from the soil seedbank in irrigated regions showed different habitats and lower grain number per panicle compared with plants spread by seed-mediated contamination. In addition, grain indexes showed that length-to-width ratio was a better indicator than awn length for distinguishing between NWR and Nicaraguan Indica cultivars. CONCLUSION: Analysis of the population structure and habitats of NWR revealed five clusters derived from seed-mediated contamination in rainfed upland regions, plants from the soil seedbank in irrigated double-cropping regions, and pollen-mediated contamination across both regions. Field weed management before harvesting and seed purification based on the length-to-width ratio can be conducted to improve the efficiency of long-term control of WR in Nicaragua. © 2022 Society of Chemical Industry.
Asunto(s)
Oryza , Grano Comestible , Oryza/genética , Malezas/genética , Semillas/genética , SueloRESUMEN
Sinking marine oil snow was found to be a major mechanism in the transport of spilled oil from the surface to the deep sea following the Deepwater Horizon (DwH) oil spill. Marine snow formation is primarily facilitated by extracellular polymeric substances (EPS), which are mainly composed of proteins and carbohydrates secreted by microorganisms. While numerous bacteria have been identified to degrade oil, there is a paucity of knowledge on bacteria that produce EPS in response to oil and Corexit exposure in the northern Gulf of Mexico (nGoM). In this study, we isolated bacteria from surface water of the nGoM that grow on oil or Corexit dispersant. Among the 100 strains isolated, nine were identified to produce remarkable amounts of EPS. 16S rRNA gene analysis revealed that six isolates (strains C1, C5, W10, W11, W14, W20) belong to the genus Alteromonas; the others were related to Thalassospira (C8), Aestuariibacter (C12), and Escherichia (W13a). The isolates preferably degraded alkanes (17-77%), over polycyclic aromatic hydrocarbons (0.90-23%). The EPS production was determined in the presence of a water accommodated fraction (WAF) of oil, a chemical enhanced WAF (CEWAF), Corexit, and control. The highest production of visible aggregates was found in Corexit followed by CEWAF, WAF, and control; indicating that Corexit generally enhanced EPS production. The addition of WAF and Corexit did not affect the carbohydrate content, but significantly increased the protein content of the EPS. On the average, WAF and CEWAF treatments had nine to ten times more proteins, and Corexit had five times higher than the control. Our results reveal that Alteromonas and Thalassospira, among the commonly reported bacteria following the DwH spill, produce protein rich EPS that could have crucial roles in oil degradation and marine snow formation. This study highlights the link between EPS production and bacterial oil-degrading capacity that should not be overlooked during spilled oil clearance.
Asunto(s)
Bacterias/clasificación , Matriz Extracelular de Sustancias Poliméricas/microbiología , Sedimentos Geológicos/microbiología , Contaminación por Petróleo/análisis , Alteromonas/clasificación , Alteromonas/aislamiento & purificación , Bacterias/aislamiento & purificación , Bacterias/metabolismo , Biodegradación Ambiental , Carbohidratos/análisis , ADN Bacteriano/genética , ADN Ribosómico/genética , Matriz Extracelular de Sustancias Poliméricas/metabolismo , Golfo de México , Filogenia , ARN Ribosómico 16S/genética , Rhodospirillaceae/clasificación , Rhodospirillaceae/aislamiento & purificaciónRESUMEN
Nanotubes are formed by self-assembly of α-lactalbumin milk protein following a different route than established for the hydrolysis which involves V8 enzyme, phosphate buffer and appropriate amounts of calcium at neutral pH. The resulting nanotubes are used as templates for the growth of conductive silver nanotubes. TEM, SEM-EDS, AFM and FTIR are used for characterization.
Asunto(s)
Lactalbúmina/química , Nanotubos/química , Plata/química , Microscopía de Fuerza Atómica , Nanotubos/ultraestructura , Polimerizacion , Multimerización de Proteína , Espectroscopía Infrarroja por Transformada de Fourier , Propiedades de SuperficieRESUMEN
OBJECTIVE: To determine whether there is an association between serum ischemia-modified albumin and the risk factor profile in type 2 diabetic patients with peripheral arterial disease and to identify the risk markers for peripheral arterial disease. METHODS: Participants included 290 patients (35.2% women) with type 2 diabetes. The ankle-brachial pressure index was measured using a standard protocol, and peripheral arterial disease was defined as an ankle-brachial index <0.90 or >1.3. The basal ischemia-modified albumin levels and clinical parameters were measured and analyzed. The risk factors for peripheral arterial disease were examined by multiple logistic analyses. RESULTS: Age, systolic blood pressure, total cholesterol, low-density lipoprotein cholesterol, urine albumin, homocysteine, and ischemia-modified albumin were significantly higher in patients with peripheral arterial disease than in disease-free patients (p<0.05), while ankle-brachial index was lower in the former group (p<0.05). Ischemia-modified albumin was positively associated with HbA1c and homocysteine levels (r = 0.220, p = 0.030; r = 0.446, p = 0.044, respectively), while no correlation was found with ankle-brachial index. Multiple logistic analyses indicated that HbA1c, systolic blood pressure, homocysteine and ischemia-modified albumin were independent risk factors for peripheral arterial disease in the diabetic subjects. CONCLUSION: The baseline ischemia-modified albumin levels were significantly higher and positively associated with HbA1c and homocysteine levels in type 2 diabetic patients with peripheral arterial disease. Ischemia-modified albumin was a risk marker for peripheral arterial disease. Taken together, these results might be helpful for monitoring diabetic peripheral arterial disease.
Asunto(s)
Diabetes Mellitus Tipo 2/sangre , Enfermedad Arterial Periférica/sangre , Factores de Edad , Anciano , Índice Tobillo Braquial , Biomarcadores/sangre , Presión Sanguínea/fisiología , Métodos Epidemiológicos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Enfermedad Arterial Periférica/fisiopatología , Albúmina Sérica , Albúmina Sérica HumanaRESUMEN
OBJECTIVE: To determine whether there is an association between serum ischemia-modified albumin and the risk factor profile in type 2 diabetic patients with peripheral arterial disease and to identify the risk markers for peripheral arterial disease. METHODS: Participants included 290 patients (35.2 percent women) with type 2 diabetes. The ankle-brachial pressure index was measured using a standard protocol, and peripheral arterial disease was defined as an ankle-brachial index <0.90 or >1.3. The basal ischemia-modified albumin levels and clinical parameters were measured and analyzed. The risk factors for peripheral arterial disease were examined by multiple logistic analyses. RESULTS: Age, systolic blood pressure, total cholesterol, low-density lipoprotein cholesterol, urine albumin, homocysteine, and ischemia-modified albumin were significantly higher in patients with peripheral arterial disease than in disease-free patients (p<0.05), while ankle-brachial index was lower in the former group (p<0.05). Ischemia-modified albumin was positively associated with HbA1c and homocysteine levels (r = 0.220, p = 0.030; r = 0.446, p = 0.044, respectively), while no correlation was found with ankle-brachial index. Multiple logistic analyses indicated that HbA1c, systolic blood pressure, homocysteine and ischemia-modified albumin were independent risk factors for peripheral arterial disease in the diabetic subjects. CONCLUSION: The baseline ischemia-modified albumin levels were significantly higher and positively associated with HbA1c and homocysteine levels in type 2 diabetic patients with peripheral arterial disease. Ischemia-modified albumin was a risk marker for peripheral arterial disease. Taken together, these results might be helpful for monitoring diabetic peripheral arterial disease.