266 research outputs found

    Gynoecium size and ovule number are interconnected traits that impact seed yield

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    Angiosperms form the biggest group of land plants and display an astonishing diversity of floral structures. The development of the flowers greatly contributed to the evolutionary success of the angiosperms as they guarantee efficient reproduction with the help of either biotic or abiotic vectors. The female reproductive part of the flower is the gynoecium (also called pistil). Ovules arise from meristematic tissue within the gynoecium. Upon fertilization, these ovules develop into seeds while the gynoecium turns into a fruit. Gene regulatory networks involving transcription factors and hormonal communication regulate ovule primordium initiation, their spacing on the placenta, and ovule development. Ovule number and gynoecium size are usually correlated and several genetic factors that impact these traits have been identified. Understanding and fine-tuning the gene regulatory networks influencing ovule number and pistil length opens up strategies for crop yield improvement, which is pivotal in light of a rapidly growing world population. In this review, we present an overview of the current knowledge of the genes and hormones involved in determining ovule number and gynoecium size. We propose a model for the gene regulatory network that guides the developmental processes that determine seed yield

    Why NIPT should be publicly funded

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    Asking pregnant women to (co)pay for non-invasive prenatal testing (NIPT) out of pocket leads to unequal access across socioeconomic strata. To avoid these social justice issues, first-trimester prenatal screening should be publicly funded in countries such as the Netherlands, with universal coverage healthcare systems that offer all other antenatal care

    Divergent responses of serum testosterone and cortisol in athlete men after a marathon race

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    Physical exercise alters homeostasis, as it requires prompt mobilization of metabolic sources. In this study, we measured serum testosterone (T) and cortisol (C) levels and the muscle-wastage enzymes CK, CKMB and LDH in 20 healthy male athletes (ages 25 to 40 years) in response to a marathon race (42.2 km). Venous blood samples were drawn in 3 different periods: (i) in the morning, 48 h before the competition (control), (ii) at the end of the race (end), and (iii) in the next morning, 20 h after the race (recovery). At the end, T was significantly lower (from 673 to 303 ng/dl) and C higher (from 20.3 to 42.5 µg/dl) as compared to the control period. At recovery, both were virtually identical to control levels. CK, CKMB and LDH were significantly higher at the end of the competition and even higher in the recovering period (except for CKMB), characterizing muscle wastage. CK and LDH disclosed a significant negative correlation with T (-0.412 and -0.546, respectively), whereas CKMB correlated positively with C (0.4521). We conclude that the inverse correlation observed between T and C levels, and the pattern of CK, CKMB and LDH increase, allow us to confirm that a marathon race may cause a marked physical stress, resulting in a distinct hormonal imbalance and severe cellular damage.O exercício físico altera a homeostase, pois requer rápida mobilização de fontes metabólicas. Neste estudo, analisamos a resposta dos níveis séricos de testosterona (T) e cortisol (C) e das enzimas de desgaste muscular CK, CKMB e LDH, em 20 atletas masculinos sadios (25 a 40 anos), participantes de uma maratona (42,2 km). Coletas de sangue venoso foram feitas em 3 períodos: (i) pela manhã, 48 h antes da maratona (controle), (ii) logo após o término da corrida (final) e (iii) na manhã seguinte, 20 h após a realização da prova (recuperação). Ao final, T estava significantemente mais baixa (de 673 para 303 ng/dl) e C mais elevado (de 20,3 para 42,5 µg/dl) que no período controle. Na recuperação, ambos praticamente retornaram aos níveis basais. CK, CKMB e LDH estavam significantemente mais elevadas ao final da corrida e mais ainda na recuperação (exceto a CKMB), caracterizando o desgaste muscular. Enquanto CK e LDH apresentaram significante correlação negativa com a T (-0,412 e -0,546, respectivamente), CKMB correlacionou-se positivamente com o C (0,4521). Concluímos que a correlação inversa entre T e C, e o comportamento das enzimas CK, CKMB e LDH, permite comprovar que uma corrida de maratona causa intenso stress físico, provocando desequilíbrio hormonal e lesão celular severa.Universidade Federal de São Paulo (UNIFESP) Departamento de Medicina Centro de Medicina da Atividade Física e do EsporteUNIFESP, Depto. de Medicina Centro de Medicina da Atividade Física e do EsporteSciEL

    REM34 and REM35 control female and male gametophyte development in Arabidopsis thaliana

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    The REproductive Meristem (REM) gene family encodes for transcription factors belonging to the B3 DNA binding domain superfamily. In Arabidopsis thaliana the REM gene family is composed of 45 members, preferentially expressed during flower, ovule and seed development. Only a few members of this family have been functionally characterized: VERNALIZATION1 (VRN1) and most recently TARGET OF FLC AND SVP1 (TFS1) regulate flowering time and VERDANDI (VDD), together with VALKYRIE (VAL) control the death of the receptive synergid cell in the female gametophyte. We investigated the role of REM34, REM35 and REM36, three closely related and linked genes similarly expressed in both female and male gametophytes. Simultaneous silencing by RNA interference (RNAi) caused about 50% of the ovules to remain unfertilized. Careful evaluation of both ovule and pollen development showed that this partial sterility of the transgenic RNAi lines was due to a post meiotic block in both female and male gametophytes. Furthermore, protein interaction assays revealed that REM34 and REM35 interact, which suggests that they work together during the first stages of gametogenesis

    Should pregnant women be charged for non-invasive prenatal screening? Implications for reproductive autonomy and equal access

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    The introduction of non-invasive prenatal testing (NIPT) in healthcare systems around the world offers an opportunity to reconsider funding policies for prenatal screening. In some countries with universal access healthcare systems, pregnant women and their partners are asked to (co)pay for NIPT. In this paper, we discuss two important rationales for charging women for NIPT: (1) to

    Drinking water temperature around the globe : understanding, policies, challenges and opportunities

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    Water temperature is often monitored at water sources and treatment works; however, there is limited monitoring of the water temperature in the drinking water distribution system (DWDS), despite a known impact on physical, chemical and microbial reactions which impact water quality. A key parameter influencing drinking water temperature is soil temperature, which is influenced by the urban heat island effects. This paper provides critique and comprehensive summary of the current knowledge, policies and challenges regarding drinking water temperature research and presents the findings from a survey of international stakeholders. Knowledge gaps as well as challenges and opportunities for monitoring and research are identified. The conclusion of the study is that temperature in the DWDS is an emerging concern in various countries regardless of the water source and treatment, climate conditions, or network characteristics such as topology, pipe material or diameter. More research is needed, especially to determine (i) the effect of higher temperatures, (ii) a legislative limit on temperature and (iii) measures to comply with this limit

    Duurzaam bodemgebruik in de landbouw, advies uit de praktijk

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    In opdracht van het Ministerie van LNV zijn in deze studie de volgende vragen beantwoord: 1. Wat is volgens de praktijk duurzaam bodemgebruik in de landbouw? Hoe wordt dit concept in de praktijk uitgewerkt? 2. Wat is volgens de praktijk de rolverdeling van de verschillende actoren (overheid (EU, nationaal, regionaal) en bedrijfsleven) in de toepassing van het concept duurzaam bodemgebruik? En hoe zou de eventuele rol van de overheid moeten worden ingevuld? De antwoorden zijn verkregen door interviews en een enquête. De resultaten zijn getoetst aan de visie van belangenbehartigers en intermediairen in de agrarische sector. Volgens agrarische ondernemers is duurzaam bodemgebruik: de grond zo gebruiken en beheren dat die ook op lange termijn van goede kwaliteit blijft voor de teelt. Een goede bodemkwaliteit wordt volgens de ondernemers vooral bepaald door het organische stofgehalte van de grond, de ontwatering, het vochtleverende vermogen, de draagkracht, de levering van nutriënten en de onkruiddruk. Een goed beheer is er op gericht dat deze zaken in orde zijn. Volgens de ondernemers zijn zij er verantwoordelijk voor de kwaliteit van de grond te handhaven: de grond geschikt te houden voor de teelt. Dat is ook in hun eigen belang, en daarvoor zijn volgens hen geen regels nodig. Verder ziet men een rol voor het bedrijfsleven in de ontwikkeling van bodemvriendelijke mechanisatie. Voor overheden zien zij een rol bij waterbeheer, goede regels (genoeg ruimte) voor organische bemesting en stimulering van duurzame praktijken

    Drinking water temperature around the globe: Understanding, policies, challenges and opportunities

    Get PDF
    Water temperature is often monitored at water sources and treatment works; however, there is limited monitoring of the water temperature in the drinking water distribution system (DWDS), despite a known impact on physical, chemical and microbial reactions which impact water quality. A key parameter influencing drinking water temperature is soil temperature, which is influenced by the urban heat island effects. This paper provides critique and comprehensive summary of the current knowledge, policies and challenges regarding drinking water temperature research and presents the findings from a survey of international stakeholders. Knowledge gaps as well as challenges and opportunities for monitoring and research are identified. The conclusion of the study is that temperature in the DWDS is an emerging concern in various countries regardless of the water source and treatment, climate conditions, or network characteristics such as topology, pipe material or diameter. More research is needed, especially to determine (i) the effect of higher temperatures, (ii) a legislative limit on temperature and (iii) measures to comply with this limit

    The Influence of Scale Preferences on the Design of a Water Innovation: A Case in Dutch River Management

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    The debate on scale use in river management focuses primarily on the (lack of) fit between the bio-geophysical and institutional systems. However, in this article we focus on the ‘subjective’ aspect of scale preferences in water governance. We apply an adapted version of the Integrated Scale Hierarchy for Rivers to determine the degree of fit between the scale preferences of the actors involved in a Dutch case study and the scale requirements of the innovative river management concept. This allows us to understand which riverine processes and characteristics are regarded as important by the different actors and to identify mismatches in scale perspectives as they manifest themselves in water management practice. We discover that inflexibility in scale use on the part of the involved actors places bounds on the design and quality of interventions and demonstrate that a more flexible use of scales in the design phase of a river management intervention has the potential to lead to more effective solutions
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