Ocorrência de cianobactérias em um reservatório de abastecimento público do semiárido cearense / Occurrence of cyanobacteria in a public supply reservoir in the semi-arid region of Ceará

As cianobactérias são organismos procariontes que apresentam propriedades tanto das algas como das bactérias. O objetivo deste trabalho foi identificar e quantificar as espécies de cianobactérias no reservatório Canoas, Ceará, Brasil, em diferentes períodos (seco e chuvoso). As amostras foram coletadas mensalmente (outubro/16 a maio/17) em três pontos amostrais (P1, P2 e P3). Considerando a análise da composição, realizou-se arrastos horizontais com rede de plâncton (20µm) na subsuperfície da água, sendo fixadas com formol neutro a 4%, analisadas utilizando-se microscópio óptico Trinocular (QUIMIS) - Motic, Modelo: Q711T – BA310. Para a quantificação, as amostras foram coletadas diretamente da subsuperfície, sendo fixadas com lugol, analisadas e contadas segundo o método de Utermöhl, utilizando-se microscópio invertido Zeiss Axiovert. Foram determinadas as densidades, espécies dominantes e abundantes. Entre os táxons, apenas duas espécies foram consideradas dominantes e quatro abundantes. A presença de grandes densidades observadas para espécies de Cyanobacteria alertam para possíveis riscos à saúde pública, visto que esse reservatório é utilizado para o abastecimento público, com isso torna-se relevante a necessidade de monitoramento constante para prevenir e minimizar possíveis transtornos que possam ocorrer pela presença da grande concentração desses organismos na água

Implicações da radiação na saúde dos profissionais que utilizam a fluoroscopia na prática diária: Implications of radiation on the health of professionals who use the fluoroscopy in daily practice

O presente estudo tem como objetivo analisar as implicações da radiação na saúde dos profissionais que utilizam o arco cirúrgico na prática diária. Neste estudo foi realizada uma revisão sistemática da literatura. Para seleção das publicações foram considerados como critérios de inclusão estar disponível em formato completo, publicado nos últimos cinco anos (2018-2022), escritas em língua portuguesa e inglesa. E como critérios de exclusão foram considerados estar foram do tema de pesquisa, ser revisão de literatura e repetido na base de dados. Os critérios de inclusão e exclusão foram considerados como meio de validade metodológica. Concluiu-se a partir desse estudo que apesar de baixos níveis de radiação emitidos por arco cirúrgico, os riscos ainda são significativos, verificando-se a necessidade de conscientização dos profissionais de saúde sobre a proteção necessária para mitigação das implicações, principalmente, entre os menos experientes.&nbsp

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

A comparison of stomatal conductance responses to blue and red light between C3 and C4 photosynthetic species in three phylogenetically-controlled experiments

Peer reviewed: TrueAcknowledgements: EB is grateful to the Institute of Crop Science, College of Agriculture and Food Science, University of the Philippines Los Ban˜os for supporting his PhD endeavor. For the purpose of open access, the author has applied a Creative Commons Attribution (CC BY) license to any Author Accepted Manuscript version arising from this submission.Introduction: C4 photosynthesis is an adaptation that has independently evolved at least 66 times in angiosperms. C4 plants, unlike their C3 ancestral, have a carbon concentrating mechanism which suppresses photorespiration, often resulting in faster photosynthetic rates, higher yields, and enhanced water use efficiency. Moreover, the presence of C4 photosynthesis greatly alters the relation between CO2 assimilation and stomatal conductance. Previous papers have suggested that the adjustment involves a decrease in stomatal density. Here, we tested if C4 species also have differing stomatal responses to environmental cues, to accommodate the modified CO2 assimilation patterns compared to C3 species. Methods: To test this hypothesis, stomatal responses to blue and red-light were analysed in three phylogenetically linked pairs of C3 and C4 species from the Cleomaceae (Gynandropsis and Tarenaya), Flaveria, and Alloteropsis, that use either C3 or C4 photosynthesis. Results: The results showed strongly decreased stomatal sensitivity to blue light in C4 dicots, compared to their C3 counterparts, which exhibited significant blue light responses. In contrast, in C3 and C4 subspecies of the monocot A. semialata, the blue light response was observed regardless of photosynthetic type. Further, the quantitative red-light response varied across species, but the presence or absence of a significant stomatal red-light response was not directly associated with differences in photosynthetic pathway. Interestingly, stomatal density and morphology patterns observed across the three comparisons were also not consistent with patterns commonly asserted for C3 and C4 species. Discussion: The strongly diminished blue-light sensitivity of stomatal responses in C4 species across two of the comparisons suggests a common C4 feature that may have functional implications. Altogether, the strong prevalence of species-specific effects clearly emphasizes the importance of phylogenetic controls in comparisons between C3 and C4 photosynthetic pathways

A comparison of stomatal conductance responses to blue and red light between C3 and C4 photosynthetic species in three phylogenetically-controlled experiments

IntroductionC4 photosynthesis is an adaptation that has independently evolved at least 66 times in angiosperms. C4 plants, unlike their C3 ancestral, have a carbon concentrating mechanism which suppresses photorespiration, often resulting in faster photosynthetic rates, higher yields, and enhanced water use efficiency. Moreover, the presence of C4 photosynthesis greatly alters the relation between CO2 assimilation and stomatal conductance. Previous papers have suggested that the adjustment involves a decrease in stomatal density. Here, we tested if C4 species also have differing stomatal responses to environmental cues, to accommodate the modified CO2 assimilation patterns compared to C3 species.MethodsTo test this hypothesis, stomatal responses to blue and red-light were analysed in three phylogenetically linked pairs of C3 and C4 species from the Cleomaceae (Gynandropsis and Tarenaya), Flaveria, and Alloteropsis, that use either C3 or C4 photosynthesis.ResultsThe results showed strongly decreased stomatal sensitivity to blue light in C4 dicots, compared to their C3 counterparts, which exhibited significant blue light responses. In contrast, in C3 and C4 subspecies of the monocot A. semialata, the blue light response was observed regardless of photosynthetic type. Further, the quantitative red-light response varied across species, but the presence or absence of a significant stomatal red-light response was not directly associated with differences in photosynthetic pathway. Interestingly, stomatal density and morphology patterns observed across the three comparisons were also not consistent with patterns commonly asserted for C3 and C4 species.DiscussionThe strongly diminished blue-light sensitivity of stomatal responses in C4 species across two of the comparisons suggests a common C4 feature that may have functional implications. Altogether, the strong prevalence of species-specific effects clearly emphasizes the importance of phylogenetic controls in comparisons between C3 and C4 photosynthetic pathways.</jats:sec

Lessons from relatives: C4 photosynthesis enhances CO2 assimilation during the low-light phase of fluctuations.

Despite the global importance of species with C4 photosynthesis, there is a lack of consensus regarding C4 performance under fluctuating light. Contrasting hypotheses and experimental evidence suggest that C4 photosynthesis is either less or more efficient in fixing carbon under fluctuating light than the ancestral C3 form. Two main issues have been identified that may underly the lack of consensus: neglect of evolutionary distance between selected C3 and C4 species and use of contrasting fluctuating light treatments. To circumvent these issues, we measured photosynthetic responses to fluctuating light across three independent phylogenetically controlled comparisons between C3 and C4 species from Alloteropsis, Flaveria, and Cleome genera under 21% and 2% O2. Leaves were subjected to repetitive stepwise changes in light intensity (800 and 100 µmol m-2 s-1 PFD) with three contrasting durations: 6, 30 and 300 seconds. These experiments reconciled the opposing results found across previous studies and showed that 1) stimulation of CO2 assimilation in C4 species during the low light phase was both stronger and more sustained than in C3 species; 2) CO2 assimilation patterns during the high light phase could be attributable to species or C4 subtype differences rather than photosynthetic pathway; and 3) the duration of each light step in the fluctuation regime can strongly influence experimental outcomes.Lucía Arce Cubas was jointly funded by The Cambridge Commonwealth, European & International Trust; and by Mexico’s Consejo Nacional de Ciencia y Tecnología (CONACyT). This work was supported by the BBSRC via grant BB/T007583/1 awarded to Dr. Johannes Kromdijk