309 research outputs found
Control of social monogamy through aggression in a hermaphroditic shrimp
<p>Abstract</p> <p>Introduction</p> <p>Sex allocation theory predicts that in small mating groups simultaneous hermaphroditism is the optimal form of gender expression. Under these conditions, male allocation is predicted to be very low and overall per-capita reproductive output maximal. This is particularly true for individuals that live in pairs, but monogamy is highly susceptible to cheating by both partners. However, certain conditions favour social monogamy in hermaphrodites. This study addresses the influence of group size on group stability and moulting cycles in singles, pairs, triplets and quartets of the socially monogamous shrimp <it>Lysmata amboinensis</it>, a protandric simultaneous hermaphrodite.</p> <p>Results</p> <p>The effect of group size was very strong: Exactly one individual in each triplet and exactly two individuals in each quartet were killed in aggressive interactions, resulting in group sizes of two individuals. All killed individuals had just moulted. No mortality occurred in single and pair treatments. The number of moults in the surviving shrimp increased significantly after changing from triplets and quartets to pairs.</p> <p>Conclusion</p> <p>Social monogamy in <it>L. amboinensis </it>is reinforced by aggressive expulsion of supernumerous individuals. We suggest that the high risk of mortality in triplets and quartets results in suppression of moulting in groups larger than two individuals and that the feeding ecology of <it>L. amboinensis </it>favours social monogamy.</p
Frontline over ivory tower: key competencies in community-based curricula
Background: The Royal College of Physicians and Surgeons of Canada mandates that community experiences be incorporated into medicine-based specialties. Presently there is wide variability in community endocrine experiences across Canadian training programs. This is complicated by the paucity of literature providing guidance on what constitutes a ‘community’ rotation.Method: A modified Delphi technique was used to determine the CanMEDS competencies best taught in a community endocrinology curriculum. The Delphi technique is a qualitative-research method that uses a series of questionnaires sent to a group of experts with controlled feedback provided by the researchers after each survey round. The experts in this study included endocrinology program directors, community endocrinologists, endocrinology residents and recent endocrinology graduates.Results: Thirty four out of 44 competencies rated by the panel were deemed suitable for a community curriculum. The experts considered the “Manager” role best taught in the community, while they considered the community least suitable to learn the “Medical Expert” competency.Conclusions: To our knowledge, this is the first time the content of a community-based subspecialty curriculum was determined using the Delphi process in Canada. These findings suggest that community settings have potential to fill in gaps in residency training in regards to the CanMEDS Manager role. The results will aid program directors in designing competency-based community endocrinology rotations and competency-based community rotations in other medical subspecialty programs
Counting: a book of lists
accordion, dos à dos, uncovered spine with two cloth covered boards; a cloth covered board folder wraps around the book and all enclosed in a cloth covered slipcase, with foil stamped title. Cover; interior pages. Taking bits of information found in old journal entries, calendars, shopping and to-do lists, the artist notes the roles she plays as wife, mother, professor, administrator, architect, and book artist. Found lists are digitally reproduced with letterpress.https://digitalcommons.risd.edu/specialcollections_artistsbooks/1022/thumbnail.jp
One clutch or two clutches? Fitness correlates of coexisting alternative female life-histories in the European earwig
Whether to reproduce once or multiple times (semelparity vs. iteroparity) is a major life-history decision that organisms have to take. Mode of parity is usually considered a species characteristic. However, recent models suggested that population properties or condition-dependent fitness payoffs could help to maintain both life-history tactics within populations. In arthropods, semelparity was also hypothesised to be a critical pre-adaptation for the evolution of maternal care, semelparous females being predicted to provide more care due to the absence of costs on future reproduction. The aim of this study was to characterize potential fitness payoffs and levels of maternal care in semel- and itero-parous females of the European earwig Forficula auricularia. Based on 15 traits measured in 494 females and their nymphs, our results revealed that iteroparous females laid their first clutch earlier, had more eggs in their first clutch, gained more weight during the 2weeks following hatching of the first clutch, but produced eggs that developed more slowly than semelparous females. Among iteroparous females, the sizes of first and second clutches were significantly and positively correlated, indicating no investment trade-off between reproductive events. Iteroparous females also provided more food than semelparous ones, a result contrasting with predictions that iteroparity is incompatible with the evolution of maternal care. Finally, a controlled breeding experiment reported full mating compatibility among offspring from females of the two modes of parity, confirming that both types of females belong to one single species. Overall, these results indicate that alternative modes of parity represent coexisting life-history tactics that are likely to be condition-dependent and associated with offspring development and specific levels of maternal care in earwig
Radiation Safety Considerations in the Treatment of Canine Skeletal Conditions Using 153Sm, 90Y, and 117mSn
Wendt, Richard E. III; Selting, Kimberly A.; Lattimer, Jimmy C.; Wong, Janine; Simón, Jaime; Stevenson, Nigel R.; Stearns, Stanley D.. Radiation Safety Considerations in the Treatment of Canine Skeletal Conditions Using 153Sm, 90Y, and 117mSn. Health Physics: June 2020 - Volume 118 - Issue 6 - p 702-710 doi: 10.1097/HP.0000000000001222https://openworks.mdanderson.org/mdacc_imgphys_pubs/1001/thumbnail.jp
The photomorphogenic factors UV-B RECEPTOR 1, ELONGATED HYPOCOTYL 5, and HY5 HOMOLOGUE are part of the UV-B signalling pathway in grapevine and mediate flavonol accumulation in response to the environment
Grapevine (Vitis vinifera L.) is a species well known for its adaptation to radiation. However, photomorphogenic factors related to UV-B responses have not been molecularly characterized. We cloned and studied the role of UV-B RECEPTOR (UVR1), ELONGATED HYPOCOTYL 5 (HY5), and HY5 HOMOLOGUE (HYH) from V. vinifera We performed gene functional characterizations, generated co-expression networks, and tested them in different environmental conditions. These genes complemented the Arabidopsis uvr8 and hy5 mutants in morphological and secondary metabolic responses to radiation. We combined microarray and RNA sequencing (RNA-seq) data with promoter inspections to identify HY5 and HYH putative target genes and their DNA binding preferences. Despite sharing a large set of common co-expressed genes, we found different hierarchies for HY5 and HYH depending on the organ and stress condition, reflecting both co-operative and partially redundant roles. New candidate UV-B gene markers were supported by the presence of HY5-binding sites. These included a set of flavonol-related genes that were up-regulated in a HY5 transient expression assay. We irradiated in vitro plantlets and fruits from old potted vines with high and low UV-B exposures and followed the accumulation of flavonols and changes in gene expression in comparison with non-irradiated conditions. UVR1, HY5, and HYH expression varied with organ, developmental stage, and type of radiation. Surprisingly, UVR1 expression was modulated by shading and temperature in berries, but not by UV-B radiation. We propose that the UV-B response machinery favours berry flavonol accumulation through the activation of HY5 and HYH at different developmental stages at both high and low UV-B exposure
A systems-oriented analysis of the grapevine R2R3-MYB transcription factor family uncovers new insights into the regulation of stilbene accumulation
R2R3-MYB transcription factors (TFs) belong to a large and functionally diverse protein superfamily in plants. In this study, we explore the evolution and function of this family in grapevine (Vitis vinifera L.), a high-value fruit crop. We identified and manually curated 134 genes using RNA-Seq data, and named them systematically according to the Super-Nomenclature Committee. We identified novel genes, splicing variants and grapevine/woody-specific duplicated subgroups, suggesting possible neo- and sub-functionalization events. Regulatory network analysis ascribed biological functions to uncharacterized genes and validated those of known genes (e.g. secondary cell wall biogenesis and flavonoid biosynthesis). A comprehensive analysis of different MYB binding motifs in the promoters of co-expressed genes predicted grape R2R3-MYB binding preferences and supported evidence for putative downstream targets. Enrichment of cis-regulatory motifs for diverse TFs reinforced the notion of transcriptional coordination and interaction between MYBs and other regulators. Analysis of the network of Subgroup 2 showed that the resveratrol-related VviMYB14 and VviMYB15 share common co-expressed STILBENE SYNTHASE genes with the uncharacterized VviMYB13. These regulators have distinct expression patterns within organs and in response to biotic and abiotic stresses, suggesting a pivotal role of VviMYB13 in regulating stilbene accumulation in vegetative tissues and under biotic stress conditions
Orchestration of the stilbene synthase gene family and their regulators by subgroup 2 MYB genes
The control of plant specialised metabolism is exerted by transcription factors and co-regulators acting on cis-regulatory DNA sequences of pathway-structural genes, determining when, where, and how metabolites are accumulated. A particularly interesting case for studying the transcriptional control of metabolism is represented by stilbenoids, produced within the phenylpropanoid pathway, as their ability to inhibit infection by coronaviruses MERS-CoV and SARS-CoV has been recently demonstrated in vitro. Integrative omic studies in grapevine (Vitis vinifera L.), including gene co-expression networks, have previously highlighted several transcription factors (TFs) from different gene families as potential modulators of stilbenoid accumulation, offering an ideal framework for gene function characterisation using genome-wide approaches. In the context of non-model plant species, DNA affinity purification sequencing (DAP-Seq) results a novel and potentially powerful tool for the analysis of novel uncharacterised regulators, however, it has not yet been applied in fruit crops. Accordingly, we tested as a proof-of-concept the binding of two previously characterised R2R3-MYB TFs to their known targets of the stilbene pathway, MYB14 and MYB15, obtaining 5,222 and 4,502 binding events assigned to 4,038 and 3,645 genes for each TF, respectively. Bound genes (putative targets) were overlapped with aggregated gene centred co-expression networks resulting in shared and exclusive High Confidence Targets (HCTs) suggesting a high, but not complete, redundancy. Our results show that in addition to the previously known but few STS targets, these regulators bind to almost half of the complete STS family in addition to other phenylpropanoid- and stilbenoid-related genes. We also suggest they are potentially involved in other processes such as the circadian rhythm or the synthesis of biotin. We searched the activated transcriptomes of transiently MYB15-overexpressing grapevine plants and observed a large activation of its high confidence targets, validating our methodological approach. Our results also show that MYB15 seems to play a role in regulating other stilbenoid-related TFs such as WRKY03.This work was supported by Grant PGC2018-099449-A-I00 and by the Ramón y Cajal program grant
RYC-2017-23645, both awarded to J.T.M. and to the FPI scholarship PRE2019-088044 granted to
L.O. from the Ministerio de Ciencia, Innovaci´on y Universidades (MCIU, Spain), Agencia Estatal de
Investigaci´on (AEI, Spain), and Fondo Europeo de Desarrollo Regional (FEDER, European Union).
C.Z. is supported by China Scholarship Council (CSC) no. 201906300087. This article is based upon
work from COST Action CA 17111 INTEGRAPE, supported by COST (European Cooperation in
Science and Technology). Data has been treated and uploaded in public repositories according to
the FAIR principles.N
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