1,768 research outputs found

    Genetic evaluation of domestication-related traits in rice: implications for the archaeobotany of rice origins

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    Domestication is the process in which preferred genetic changes in wild plants and animals have been selected by humans. In other words, domesticated plants have become adapted to being part of human-managed ecosystems. Asian cultivated rice, Oryza sativa L., is one of the most important crops in the world and is known to have been domesticated from its wild ancestor, O. rufipogon. Many morphological changes in cultivated rice have been beneficial to humans in terms of increased efficiency of cultivation and yield that supported the development of human civilisations. The genetic mechanisms of these changes have been extensively studied since rice genome sequences were determined, and based on genome analyses, the origin of rice has been widely discussed. Most of the domestication-related traits and genes are, however, often evaluated based on the genetic background of cultivated rice, leading to misinterpretation of rice domestication. Here, we review several genetic changes and discuss the importance of evaluating these traits in the wild rice genetic background to understand the process of rice domestication. In this review, we also provide a phenotypic evaluation of domestication-related traits

    ALFALFA (Medicago sativa L.) CULTIVADA EN CAMPECHE, MÉXICO Y SU INTEGRACIÓN LOCAL EN LA ALIMENTACIÓN DE CORDEROS EN CONFINAMIENTO

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    The use of different diets based on cultivated alfalfa hay (Medicago sativa L.) in Campeche was compared, and its relation with a commercial concentrate and Taiwan grass (Pennisetum purpureum): T1=commercial concentrate, T2=T1+alfalfa hay, T3=T1+Taiwan grass, T4=alfalfa hay. The productive and metabolic behavior of lambs was evaluated in an intensive system using 20 male lambs with crosses of Pelibuey, Dorper and Black Belly of 12.5±1 kg live weight (LW). The consumption of total dry matter (TDM), the daily weight gain (DWG), dietary conversion (DC), and in situ digestibility of the dry matter (ISDDM) were measured. The pH, ammonia nitrogen (NH3) and concentration of volatile fatty acids (VFA) in ruminal liquid were also evaluated. The best DWG in grams per day, of 234 g (p?0.05) was obtained with T2; in contrast, T3 showed the lowest DWG. The diet that included the mixture of alfalfa hay and concentrate improved significantly the conditions of the variables pH, NH3 and VFA (p?0.05).Se comparó el uso de diferentes dietas con base en heno de alfalfa cultivada (Medicago sativa L.) en Campeche y su relación con un concentrado comercial y pasto Taiwán (Pennisetum purpureum), T1=concentrado comercial, T2=T1+heno de alfalfa, T3=T1+pasto Taiwán, T4=heno de alfalfa. Se evaluó el comportamiento productivo y metabólico de corderos en sistema intensivo utilizando 20 corderos machos con encaste de Pelibuey, Dorper y Black Belly de 12.5±1 kg de peso vivo (PV). Se midió el consumo de materia seca total (CMS), la ganancia diaria de peso (GDP), la conversión alimenticia (CA), y la digestibilidad in situ de la materia seca (DISMS). También fueron evaluados el pH, nitrógeno amoniacal (NH3) y la concentración de ácidos grasos volátiles (AGV) en líquido ruminal. La mejor GDP en gramos por día, de 234 g (p?0.05) se obtuvo en el T2; en contraste, el T3 mostró la menor GDP. La dieta que incluyó la mezcla de heno de alfalfa y concentrado mejoró significativamente las condiciones de las variables pH, NH3 y AGV (p?0.05)

    Hunter-gatherer specialization in the late Neolithic of southern Vietnam - The case of Rach Nui

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    Rach Nui is a late Neolithic settlement of hunter-gatherers in southern Vietnam. However, the site also has a series of mortared floors corresponding to a sedentary lifestyle, where the inhabitants continued to live in the same area and repaired or replaced their floors over a period of 150 years. The inhabitants relied on a mixed economy that included domesticated and gathered plants, as well as hunted and managed animals. Although, there is evidence for the consumption of domesticated rice and foxtail millet, the inhabitants were mainly hunter-gatherers who relied on their surrounding mangrove and swamp forest habitats for most of their food requirements. From the archaeobotanical work done, it appears that the domesticated cereals, rice and foxtail millet, found at the site were imported. On the other hand, sedge nutlets and parenchyma were identified in high frequencies and were probably locally sourced, suggesting that foraging and/or vegeculture played a major role in the economy of Rach Nui

    Re-evaluating Pleistocene-Holocene occupation of cave sites in north-west Thailand: New radiocarbon and luminescence dating

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    Established chronologies indicate a long-term 'Hoabinhian' hunter-gatherer occupation of Mainland Southeast Asia during the Terminal Pleistocene to Mid-Holocene (45 000-3000 years ago). Here, the authors re-examine the 'Hoabinhian' sequence from north-west Thailand using new radiocarbon and luminescence data from Spirit Cave, Steep Cliff Cave and Banyan Valley Cave. The results indicate that hunter-gatherers exploited this ecologically diverse region throughout the Terminal Pleistocene and the Pleistocene-Holocene transition, and into the period during which agricultural lifeways emerged in the Holocene. Hunter-gatherers did not abandon this highland region of Thailand during periods of environmental and socioeconomic change

    Social responses to climate change in Iron Age north-east Thailand: New archaeobotanical evidence

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    New evidence from archaeological investigations in north-east Thailand shows a transition in rice farming towards wetland cultivation that would have facilitated greater yields and surpluses. This evidence, combined with new dates and palaeoclimatic data, suggests that this transition took place in the Iron Age, at a time of increasingly arid climate, and when a number of broader societal changes become apparent in the archaeological record. For the first time, it is possible to relate changes in subsistence economy to shifts in regional climate and water-management strategies, and to the emergence of state societies in Southeast Asia

    Phenoloxidase activity acts as a mosquito innate immune response against infection with semliki forest virus

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    Several components of the mosquito immune system including the RNA interference (RNAi), JAK/STAT, Toll and IMD pathways have previously been implicated in controlling arbovirus infections. In contrast, the role of the phenoloxidase (PO) cascade in mosquito antiviral immunity is unknown. Here we show that conditioned medium from the Aedes albopictus-derived U4.4 cell line contains a functional PO cascade, which is activated by the bacterium Escherichia coli and the arbovirus Semliki Forest virus (SFV) (Togaviridae; Alphavirus). Production of recombinant SFV expressing the PO cascade inhibitor Egf1.0 blocked PO activity in U4.4 cell- conditioned medium, which resulted in enhanced spread of SFV. Infection of adult female Aedes aegypti by feeding mosquitoes a bloodmeal containing Egf1.0-expressing SFV increased virus replication and mosquito mortality. Collectively, these results suggest the PO cascade of mosquitoes plays an important role in immune defence against arboviruses

    Cytotoxic and antibacterial activities of endophytic fungi isolated from plants at the National Park, Pahang, Malaysia

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    <p>Abstract</p> <p>Background</p> <p>Endophytes, microorganisms which reside in plant tissues, have potential in producing novel metabolites for exploitation in medicine. Cytotoxic and antibacterial activities of a total of 300 endophytic fungi were investigated.</p> <p>Methods</p> <p>Endophytic fungi were isolated from various parts of 43 plants from the National Park Pahang, Malaysia. Extracts from solid state culture were tested for cytotoxicity against a number of cancer cell lines using the MTT assay. Antibacterial activity was determined using the disc diffusion method.</p> <p>Results</p> <p>A total of 300 endophytes were isolated from various parts of plants from the National Park, Pahang. 3.3% of extracts showed potent (IC<sub>50 </sub>< 0.01 μg/ml) cytotoxic activity against the murine leukemic P388 cell line and 1.7% against a human chronic myeloid leukemic cell line K562. <it>Sporothrix </it>sp. (KK29FL1) isolated from <it>Costus speciosus </it>showed strong cytotoxicity against colorectal carcinoma (HCT116) and human breast adenocarcinoma (MCF7) cell lines with IC<sub>50 </sub>values of 0.05 μg/ml and 0.02 μg/ml, respectively. Antibacterial activity was demonstrated for 8% of the extracts.</p> <p>Conclusion</p> <p>Results indicate the potential for production of bioactive agents from endophytes of the tropical rainforest flora.</p

    Pyrimidine biosynthesis is not an essential function for trypanosoma brucei bloodstream forms

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    &lt;p&gt;Background: African trypanosomes are capable of both pyrimidine biosynthesis and salvage of preformed pyrimidines from the host, but it is unknown whether either process is essential to the parasite.&lt;/p&gt; &lt;p&gt;Methodology/Principal Findings: Pyrimidine requirements for growth were investigated using strictly pyrimidine-free media, with or without single added pyrimidine sources. Growth rates of wild-type bloodstream form Trypanosoma brucei brucei were unchanged in pyrimidine-free medium. The essentiality of the de novo pyrimidine biosynthesis pathway was studied by knocking out the PYR6-5 locus that produces a fusion product of orotate phosphoribosyltransferase (OPRT) and Orotidine Monophosphate Decarboxylase (OMPDCase). The pyrimidine auxotroph was dependent on a suitable extracellular pyrimidine source. Pyrimidine starvation was rapidly lethal and non-reversible, causing incomplete DNA content in new cells. The phenotype could be rescued by addition of uracil; supplementation with uridine, 2′deoxyuridine, and cytidine allowed a diminished growth rate and density. PYR6-5−/− trypanosomes were more sensitive to pyrimidine antimetabolites and displayed increased uracil transport rates and uridine phosphorylase activity. Pyrimidine auxotrophs were able to infect mice although the infection developed much more slowly than infection with the parental, prototrophic trypanosome line.&lt;/p&gt; &lt;p&gt;Conclusions/Significance: Pyrimidine salvage was not an essential function for bloodstream T. b. brucei. However, trypanosomes lacking de novo pyrimidine biosynthesis are completely dependent on an extracellular pyrimidine source, strongly preferring uracil, and display reduced infectivity. As T. brucei are able to salvage sufficient pyrimidines from the host environment, the pyrimidine biosynthesis pathway is not a viable drug target, although any interruption of pyrimidine supply was lethal.&lt;/p&gt

    Evaluation of fluoride release from experimental TiF4 and NaF varnishes in vitro

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    Fluoride varnishes play an important role in the prevention of dental caries, promoting the inhibition of demineralization and the increase of remineralization. OBJECTIVE: This study aimed to analyze the amount of fluoride released into water and artificial saliva from experimental TiF(4 )and NaF varnishes, with different concentrations, for 12 h. MATERIAL AND METHODS: Fluoride varnishes were applied on acrylic blocks and then immersed in 10 ml of deionized water and artificial saliva in polystyrene bottles. The acrylic blocks were divided in seven groups (n=10): 1.55% TiF(4 )varnish (0.95% F, pH 1.0); 3.10% TiF(4 )varnish (1.90% F, pH 1.0); 3.10% and 4% TiF(4 )varnish (2.45% F, pH 1.0); 2.10% NaF varnish (0.95% F, pH 5.0); 4.20% NaF varnish (1.90% F, pH 5.0); 5.42% NaF varnish (2.45% F, pH 5.0) and control (no treatment, n=5). The fluoride release was analyzed after 1/2, 1, 3, 6, 9 and 12 h of exposure. The analysis was performed using an ion-specific electrode coupled to a potentiometer. Two-way ANOVA and Bonferroni's test were applied for the statistical analysis (p<0.05). RESULTS: TiF(4 )varnishes released larger amounts of fluoride than NaF varnishes during the first 1/2 h, regardless of their concentration; 4% TiF(4) varnish released more fluoride than NaF varnishes for the first 6 h. The peak of fluoride release occurred at 3 h. There was a better dose-response relationship among the varnishes exposed to water than to artificial saliva. CONCLUSIONS: The 3.10% and 4% TiF(4 )-based varnishes have greater ability to release fluoride into water and artificial saliva compared to NaF varnish; however, more studies must be conducted to elucidate the mechanism of action of TiF(4 )varnish on tooth surface

    A mutation in the viral sensor 2'-5'-oligoadenylate synthetase 2 causes failure of lactation.

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    We identified a non-synonymous mutation in Oas2 (I405N), a sensor of viral double-stranded RNA, from an ENU-mutagenesis screen designed to discover new genes involved in mammary development. The mutation caused post-partum failure of lactation in healthy mice with otherwise normally developed mammary glands, characterized by greatly reduced milk protein synthesis coupled with epithelial cell death, inhibition of proliferation and a robust interferon response. Expression of mutant but not wild type Oas2 in cultured HC-11 or T47D mammary cells recapitulated the phenotypic and transcriptional effects observed in the mouse. The mutation activates the OAS2 pathway, demonstrated by a 34-fold increase in RNase L activity, and its effects were dependent on expression of RNase L and IRF7, proximal and distal pathway members. This is the first report of a viral recognition pathway regulating lactation
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