385 research outputs found

    Damage-induced phosphorylation of Sld3 is important to block late origin firing.

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    Origins of replication are activated throughout the S phase of the cell cycle such that some origins fire early and others fire late to ensure that each chromosome is completely replicated in a timely fashion. However, in response to DNA damage or replication fork stalling, eukaryotic cells block activation of unfired origins. Human cells derived from patients with ataxia telangiectasia are deficient in this process due to the lack of a functional ataxia telangiectasia mutated (ATM) kinase and elicit radioresistant DNA synthesis after γ-irradiation(2). This effect is conserved in budding yeast, as yeast cells lacking the related kinase Mec1 (ATM and Rad3-related (ATR in humans)) also fail to inhibit DNA synthesis in the presence of DNA damage. This intra-S-phase checkpoint actively regulates DNA synthesis by inhibiting the firing of late replicating origins, and this inhibition requires both Mec1 and the downstream checkpoint kinase Rad53 (Chk2 in humans). However, the Rad53 substrate(s) whose phosphorylation is required to mediate this function has remained unknown. Here we show that the replication initiation protein Sld3 is phosphorylated by Rad53, and that this phosphorylation, along with phosphorylation of the Cdc7 kinase regulatory subunit Dbf4, blocks late origin firing in Saccharomyces cerevisiae. Upon exposure to DNA-damaging agents, cells expressing non-phosphorylatable alleles of SLD3 and DBF4 (SLD3-m25 and dbf4-m25, respectively) proceed through the S phase faster than wild-type cells by inappropriately firing late origins of replication. SLD3-m25 dbf4-m25 cells grow poorly in the presence of the replication inhibitor hydroxyurea and accumulate multiple Rad52 foci. Moreover, SLD3-m25 dbf4-m25 cells are delayed in recovering from transient blocks to replication and subsequently arrest at the DNA damage checkpoint. These data indicate that the intra-S-phase checkpoint functions to block late origin firing in adverse conditions to prevent genomic instability and maximize cell survival

    Current Advances in Detection and Treatment of Babesiosis

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    Babesiosis is a disease with a world-wide distribution affecting many species of mammals principally cattle and man. The major impact occurs in the cattle industry where bovine babesiosis has had a huge economic effect due to loss of meat and beef production of infected animals and death. Nowadays to those costs there must be added the high cost of tick control, disease detection, prevention and treatment. In almost a century and a quarter since the first report of the disease, the truth is: there is no a safe and efficient vaccine available, there are limited chemotherapeutic choices and few low-cost, reliable and fast detection methods. Detection and treatment of babesiosis are important tools to control babesiosis. Microscopy detection methods are still the cheapest and fastest methods used to identify Babesia parasites although their sensitivity and specificity are limited. Newer immunological methods are being developed and they offer faster, more sensitive and more specific options to conventional methods, although the direct immunological diagnoses of parasite antigens in host tissues are still missing. Detection methods based on nucleic acid identification and their amplification are the most sensitive and reliable techniques available today; importantly, most of those methodologies were developed before the genomics and bioinformatics era, which leaves ample room for optimization. For years, babesiosis treatment has been based on the use of very few drugs like imidocarb or diminazene aceturate. Recently, several pharmacological compounds were developed and evaluated, offering new options to control the disease. With the complete sequence of the Babesia bovis genome and the B. bigemina genome project in progress, the post-genomic era brings a new light on the development of diagnosis methods and new chemotherapy targets. In this review, we will present the current advances in detection and treatment of babesiosis in cattle and other animals, with additional reference to several apicomplexan parasites

    Fibroma desmoplásico, reporte de un caso y revisión de la literatura

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    ResumenEl fibroma desmoplásico es una lesión neoplásica relativamente rara. Se considera un tumor primario de hueso, que se presenta comúnmente en la región mandibular. Se define como un tumor benigno caracterizado por la formación de abundante matriz y fibras colágenas. En marzo de 2004 se presenta el caso de un paciente de 15 años, varón, con aumento gradual en la región derecha de la mandíbula de 4 meses de evolución. Se manifiesta asintomático, con aumento de volumen, con una apariencia radiográfica y tomográfica bien delimitada radiolúcida. A la exploración se observa un infiltrado a través de la cortical lingual. La lesión es similar a las descritas en la literatura de fibroma desmoplásico.AbstractDesmoplastic fibroma (fibromatosis) is rarely seen a primary tumor of bone. Its occurrence as a central lesion in the jaws is even more uncommon. It is rare tumor of bone, especially in the mandibule. In march 2004, a 15 year-old boy presented, with a 4 month history of gradual enlargement of the right mandibule. Painless intraoral and extraoral swelling, the cortical plate of bone overlying the lesions is expanded with thinning, erosion, and infiltration into the surrounding tissues. The lesion is similar to the one described on the articule

    Characterization of ‘Wonderful’ pomegranate in the state of Chihuahua, México

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    The consumption of fruits rich in antioxidants has increased in recent years, a clear example of this is the pomegranate (Punica granatum L.). The cultivation of the pomegranate shows great expectations due to its profitability and its adaptability to development in arid zones. In this research, ‘Wonderful’ pomegranate fruits from Coyame Chihuahua, México were used. Quality parameters and bioactive compounds were evaluated to characterize the pomegranate produced in the state of Chihuahua, six different lots from local producers were used. The results showed significance between the different treatments, lot 5 (L5) presented the best quality characteristics such as: weight, diameter, lower percentage of shell and cartilage, as well as one of the highest percentages of arils, in addition, it had a high Total Soluble Solids (TSS) content, a high Titratable Acidity (TA) and a low sugar-acidity ratio, however, lot 3 (L3) showed the highest antioxidant capacity. In general, the qualities and attributes of the Chihuahua pomegranates, obtained higher values ​​in most of the evaluated variables in comparison with other reported results. On the other hand, as a result of this research, the implementation of the color index in the peel is proposed as a tool for the prediction of the maturity index of the pomegranate. This study contributes to the producers of this fruit tree because there is little information on the production and characterization of the pomegranate

    Comparison of the value of PCNA and Ki-67 as markers of cell proliferation in ameloblastic tumors

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    Objectives: The aim of this study was to compare among PCNAand Ki-67 as the most reliable immunohisto chemical marker for evaluating cell proliferation in ameloblastic tumors. Study Design: Observational, retrospective, and descriptive study of a large series of ameloblastic tumors, com- D esign: Observational, retrospective, and descriptive study of a large series of ameloblastic tumors, com- esign: Observational, retrospective, and descriptive study of a large series of ameloblastic tumors, com posed of 161 ameloblastomas and four ameloblastic carcinomas, to determine and compare PCNA and Ki-67 expression using immunohistochemistry techniques. Results: When analyzing Ki-67 positivity, the desmoplastic ameloblastoma demonstrated a significantly lower proliferation rate (1.9%) compared with the solid/multicystic and unicystic ameloblastomas and ameloblastic car cinomas (p<0.05), whereas the ameloblastic carcinomas displayed a significantly higher rate compared with all of the other ameloblastomas (48.7%) (p<0.05). When analyzing cell proliferation with PCNA, we found significant differences only between the ameloblastic carcinomas (93.3%) and the desmoplastic ameloblastomas (p<0.05). When differences between the immunopositivity for PCNA and Ki-67 were compared, the percentages were higher for PCNA in all types of ameloblastomas and ameloblastic carcinomas. In all cases, the percentages were greater than 80%, whereas the immunopositivity for Ki-67 was significantly lower; for example, the ameloblastic carcinoma expressed the highest positivity and only reached 48.7%, compared to 93.3% when we used PCNA. Conclusions: In the present study, when we used the proliferation cell marker Ki-67, the percentages of positiv ity were more specific and varied among the different types of ameloblastomas, suggesting that Ki-67 is a more specific marker for the proliferation of ameloblastic tumor cell

    Nutritional standards through Integrated Differential Diagnosis (IDD) in pomegranate (Punica granatum L.)

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    The foliar analysis is a useful tool to detect the nutritional status of plants, predict future problems in the reproductive cycles of fruit production and implement preventive and corrective measures to achieve a mineral balance in fruit trees, obtaining higher productivity. There is little information available on nutrient sufficiency ranges in pomegranate leaf and the literature reported differs due to diverse cultivation practices, cultivars, and agroecological conditions. Therefore, the objective of this work was to determine the mineral content of ‘Wonderful’ pomegranate leaves for each the nutritional elements and the cation balance, and to establish the nutritional standards using Integrated Differential Diagnosis (IDD). The mineral content of the pomegranate leaves was determined and based on the results, nutritional standards for macro elements, cation balance and microelements were generated through the IDD, which evaluate whether there are mineral and/or physiological imbalances. The macro elements in the cultivation of the pomegranate were the following: NO3 3747.5 µg g-1, Total Nitrogen 1.35%, P 0.14%, K 0.88%, Ca 1.65%, Mg 0.19%, Na 0.006%. For the cation balance, the optimal values ​​were: (Ca+Mg)/K 4.48 mEq 100 g-1, Ca/(K+Mg) 2.13 mEq 100 g-1, Mg/(K+Ca) 0.16 mEq 100 g-1, Ca/Mg 5.06 mEq 100 g-1, K/Mg 1.36 mEq 100 g-1. Finally, the optimal values ​​for the microelements were: Fe 59.5 µg g-1, Mn 31.4 µg g-1, Zn 6.3 µg g-1, Cu 6.1 µg g-1. The values ​​obtained for the micro and macro elements were like those reported. In the case of cation balance and foliar nitrate content, they have not been previously reported. The IDD is a promising and effective auxiliary tool to characterize the nutritional status of pomegranate trees and, in turn, an alternative to conventional methods of nutritional diagnosis with the advantage of establishing a nutritional deficiency (soil-plant relationship) or a physiological imbalance (relation plant - climate) for this crop

    PDB27 A MULTIDIMENSIONAL HEALTH CARE INTERVENTION ASSESSMENT: THE CO-ORDINATED DIABETES HEALTHCARE NETWORK

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    Screening of bacterial endophytes able to promote plant growth and increase salinity tolerance

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    Bacterial endophytes can colonize plant tissues without harming the plant. Instead, they are often able to increase plant growth and tolerance to environmental stresses. In this work, new strains of bacterial endophytes were isolated from three economically important crop plants (sorghum, cucumber and tomato) grown in three different regions in soils with different management. All bacterial strains were identified by 16S rRNA sequencing and characterized for plant beneficial traits. Based on physiological activities, we selected eight strains that were further tested for their antibiotic resistance profile and for the ability to efficiently colonize the interior of sorghum plants. According to the results of the re-inoculation test, five strains were used to inoculate sorghum seeds. Then, plant growth promotion activity was assessed on sorghum plants exposed to salinity stress. Only two bacterial endophytes increased plant biomass, but three of them delayed or reduced plant salinity stress symptoms. These five strains were then characterized for the ability to produce the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase, which is involved in the increase of stress tolerance. Pseudomonas brassicacearum SVB6R1 was the only strain that was able to produce this enzyme, suggesting that ACC deaminase is not the only physiological trait involved in conferring plant tolerance to salt stress in these bacterial strains

    Experimental investigation of steel building gravity framing systems under strong earthquake shaking

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    Hybrid simulations were conducted to evaluate the system-level seismic response of a 4-story steel moment frame building and its gravity framing system through various levels of ground motion shaking. The experimental substructure examined in detail corresponds to a half-scale 1½-bay by 1½-story subassembly of the steel gravity frame. Unlike typical beam-to-column connection tests, the subassembly, which represented typical gravity framing steel construction, captured the redistribution of force demands in beams, columns, panel zones, and the composite floor slab while exhibiting inelastic behavior. Horizontal as well as varying vertical forces were applied on the test specimen to mimic realistic boundary and loading conditions. This paper focuses on the experimental response of the gravity framing system and its contribution to the lateral resistance of a steel frame building. In particular, the lateral resistance and failure mechanisms of the test frame are described and compared to numerical simulations based on state-of-the-art modeling approaches. The data generated from these experiments provides valuable insight on gravity frame behavior towards improvement and verification of frame models at the system level

    Electrochemical study of H3PMo12 retention on Vulcan carbon grafted with NH2 and OH groups

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    In this work, we show a comparative study based on the effects of specific chemical functional groups (–OH, –NH2), grafted on Vulcan carbon (VC) with the incorporation of a specific polyoxometalate (POM), PMo12 (H3PMo12O40), to improve electrochemical performance. We observed a decrease in the specific surface area of the grafted matrices (VC-OH and VC-NH2) [1], and the same trend was observed for PMo12 (POM) incorporation. Our electrochemical studies showed low concentrations of POM in unmodified VCs and higher POM concentrations for grafted matrices (VC-OH and VC-NH2) after 500 voltammetric cycles, especially for the VC grafted with –OH groups (VC-OH-POM). Mechanisms have been proposed for POM interaction with the grafted groups in carbon, emphasizing the role of aqueous medium and redox activity of POM. Cyclic voltammograms suggested the POM anchoring through –OH groups with a strong interaction as a covalent bond, resulting in a surface coverage of 1.66 × 10−11 mol cm−2. Surface modifications could be extrapolated to other carbons, and the materials could be employed for different potential applications such as photocatalysis, amperometric sensors, fuel cells, and supercapacitors.Fil: Cuentas Gallegos, Ana Karina. Universidad Nacional Autónoma de México; México. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: López Cortina, S.. Universidad Autonoma de Nuevo Leon; MéxicoFil: Brousse, T.. Université de Nantes. Institut Des Materiaux Jean Rouxel; FranciaFil: Pacheco Catalán, D.. Centro de Investigación Científica de Yucatán; MéxicoFil: Fuentes Quezada, Eduardo. Centro de Investigación y Desarrollo Tecnológico en Electroquímica; México. Universidad Nacional Autónoma de México; México. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mosqueda, H.. Universidad Autonoma de Nuevo Leon; MéxicoFil: Orozco Gamboa, G.. Centro de Investigación y Desarrollo Tecnológico en Electroquímica; Méxic
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