Diversity of a cytokinin dehydrogenase gene in wild and cultivated barley

The cytokinin dehydrogenase gene HvCKX2.1 is the regulatory target for the most abundant heterochromatic small RNAs in drought-stressed barley caryopses. We investigated the diversity of HvCKX2.1 in 228 barley landraces and 216 wild accessions and identified 14 haplotypes, five of these with ten or more members, coding for four different protein variants. The third largest haplotype was abundant in wild accessions (51 members), but absent from the landrace collection. Protein structure predictions indicated that the amino acid substitution specific to haplotype 3 could result in a change in the functional properties of the HvCKX2.1 protein. Haplotypes 1–3 have overlapping geographical distributions in the wild population, but the average rainfall amounts at the collection sites for haplotype 3 plants are significantly higher during November to February compared to the equivalent data for plants of haplotypes 1 and 2. We argue that the likelihood that haplotype 3 plants were excluded from landraces by sampling bias that occurred when the first wild barley plants were taken into cultivation is low, and that it is reasonable to suggest that plants with haplotype 3 are absent from the crop because these plants were less suited to the artificial conditions associated with cultivation. Although the cytokinin signalling pathway influences many aspects of plant development, the identified role of HvCKX2.1 in the drought response raises the possibility that the particular aspect of cultivation that mitigated against haplotype 3 relates in some way to water utilization. Our results therefore highlight the possibility that water utilization properties should be looked on as a possible component of the suite of physiological adaptations accompanying the domestication and subsequent evolution of cultivated barley

Apnea of prematurity: from cause to treatment

Apnea of prematurity (AOP) is a common problem affecting premature infants, likely secondary to a “physiologic” immaturity of respiratory control that may be exacerbated by neonatal disease. These include altered ventilatory responses to hypoxia, hypercapnia, and altered sleep states, while the roles of gastroesophageal reflux and anemia remain controversial. Standard clinical management of the obstructive subtype of AOP includes prone positioning and continuous positive or nasal intermittent positive pressure ventilation to prevent pharyngeal collapse and alveolar atelectasis, while methylxanthine therapy is a mainstay of treatment of central apnea by stimulating the central nervous system and respiratory muscle function. Other therapies, including kangaroo care, red blood cell transfusions, and CO2 inhalation, require further study. The physiology and pathophysiology behind AOP are discussed, including the laryngeal chemoreflex and sensitivity to inhibitory neurotransmitters, as are the mechanisms by which different therapies may work and the potential long-term neurodevelopmental consequences of AOP and its treatment

A domestication history of dynamic adaptation and genomic deterioration in Sorghum

The evolution of domesticated cereals was a complex interaction of shifting selection pressures and repeated introgressions. Genomes of archaeological crops have the potential to reveal these dynamics without being obscured by recent breeding or introgression. We report a temporal series of archaeogenomes of the crop sorghum (Sorghum bicolor) from a single locality in Egyptian Nubia. These data indicate no evidence for the effects of a domestication bottleneck but instead suggest a steady decline in genetic diversity over time coupled with an accumulating mutation load. Dynamic selection pressures acted sequentially on architectural and nutritional domestication traits, and adaptation to the local environment. Later introgression between sorghum races allowed exchange of adaptive traits and achieved mutual genomic rescue through an ameliorated mutation load. These results reveal a model of domestication in which genomic adaptation and deterioration was not focused on the initial stages of domestication but occurred throughout the history of cultivation

Evento com aparente risco de morte: uma revisão Evento con aparente riesgo de muerte (alte): una revisión Apparent life-threatening event: a review

OBJETIVO: Realizar uma revisão crítica reunindo informações disponíveis a respeito dos eventos com aparente risco de morte. FONTES DE DADOS: Revisão bibliográfica dos artigos (em português, inglês e espanhol) obtidos dos bancos de dados eletrônicos Medline, Lilacs e SciELO, utilizando as palavras-chave: eventos com aparente risco de morte, evento com aparente risco de vida infantil, lactente, apneia, monitorização e cianose. SÍNTESE DOS DADOS: Os eventos com aparente risco de mortesão súbitos e caracterizados por uma combinação de apneia, alteração na coloração da pele e tônus muscular, com inúmeras causas subjacentes. Sua incidência verdadeira é desconhecida e a faixa etária mais acometida é de 11 a 12 semanas. Não há correlação entre o evento com aparente risco de morte e a síndrome da morte súbita do lactente, embora já tenham sido consideradas manifestações da mesma doença. Muitas vezes, o lactente tem aparência saudável ao ser avaliado pelo pediatra após apresentar eventos com aparente risco de morte, porém, isso não afasta a possibilidade de existir uma doença grave associada ao evento, que deve ser investigada e tratada. Quando não são encontradas as causas, o evento é idiopático, geralmente com boa evolução. CONCLUSÕES: É necessário investigar os lactentes levados ao pronto-socorro após apresentarem eventos com aparente risco de morte, devido ao risco de sequelas e mortalidade. Não há uma padronização das condutas a serem realizadas diante de um lactente com aparência saudável que tenha evento com aparente risco de morte, mas recomenda-se que o paciente seja internado e a causa do evento, investigada. A observação e o monitoramento em ambiente hospitalar devem ocorrer no mínimo 24 horas após o evento.<br>OBJETIVO: Realizar una revisión crítica, reuniendo las informaciones disponibles respecto a los Eventos con Aparente Riesgo de Muerte (ALTE - Apparent life-threatening event). FUENTES DE DATOS: Revisión bibliográfica de los artículos (en portugués, inglés y español) obtenidos de las bases de datos electrónicas MEDLINE, LILACS y SCIELO, utilizándose las palabras clave ALTE, evento con aparente riesgo de vida infantil, lactante, apnea, monitorización y cianosis. SÍNTESIS DE LOS DATOS: Los ALTE (apparent life-threatening event) son eventos súbitos y caracterizados por una combinación de apnea, alteración en la coloración de la piel y tono muscular, con innúmeras causas subyacentes. Su incidencia verdadera es desconocida y la franja de edad más acometida es de 11 a 12 semanas. No hay correlación entre ALTE y SIDS (Síndrome de la Muerte Súbita del Lactante), aunque ya hayan sido consideradas manifestaciones de la misma enfermedad. Muchas veces, el lactante tiene apariencia sana al ser evaluado por el pediatra después de presentar ALTE, pero eso no aleja la posibilidad de que exista una enfermedad grave asociada al evento, la cual se debe investigar y tratar. Cuando no se encuentran causas, el evento es idiopático, generalmente con buena evolución. CONCLUSIONES: Es necesario investigar los lactantes llevados a la emergencia después de presentar ALTE, por riesgo de secuelas y de mortalidad. No hay una estandarización de las conductas a tomar frente a un lactante con apariencia sana que presentó ALTE, pero se recomienda que se interne el paciente y se investigue la causa del evento. La observación y monitoración en ambiente hospitalaria debe ocurrir por un mínimo de 24 horas después del evento.<br>OBJECTIVE: To perform a critical review by gathering all the available information about apparent life-threatening events. DATA SOURCES: Bibliographic review of the articles published in Portuguese, English and Spanish from the electronic databases Medline, Lilacs and SciELO, using the key-words: apparent life-threatening events, apparent life-threatening event, infant, apnea, monitoring, and cyanosis. DATA SYNTHESIS: Apparent life-threatening events define sudden events with, a combination of apnea, color change, and marked change in the muscle tone, that have various underlying causes. The real incidence remains unknown, and it affects infants from 11 to 12 weeks of age. There is no association between apparent life-threatening events and sudden infant death syndrome. There are many possible causes for the events, and they must be investigated even in apparently healthy infants, because the presence of a severe underlying disease associated with the event is possible. If the cause of the apparent life-threatening events is found, it must be treated properly. If there is no explainable cause, the event is considered idiopathic and generally has a benign course. CONCLUSIONS: It is necessary to investigate all the infants taken to the pediatric emergency unit after experiencing an apparent life-threatening event, since there is the risk of morbidity caused by an underlying disease or the event itself, as well as subsequent mortality. Consensus guidelines about the investigation in apparently healthy infants who experienced apparent life-threatening events are not available. Most authors recommend that careful observation and hospital monitoring should be performed for at least for 24 hours after the event