Reproductive characteristics that favor invasiveness in Leonotis nepetifolia (L.) R. Br.

Reproductive systems are life attributes important in defining the demography and genetic constitution of invasive alien species populations. We describe the phenology, floral behavior and floral visitors in Mexican populations of Leonotis nepetifolia considered invasive in America, Asia and Oceania. The mating system was determined through pollination experiments and, with a morphological analysis of flowers (outcrossing index, OCI) and pollen/ovule ratio, the breeding system was evaluated. Germination of 1 and 2-year-old seeds was tested to assess the potential characteristics of germination. Leonotis nepetifolia was reproductive for 7 months (June to December) and tended towards a specific season during autumn. Anthesis lasted 36 hr with protogyny and no hercogamy, with floral visitors of Apodiformes, Hymenoptera, Lepidoptera and Thysanoptera. Pollination experiments indicated a mixed mating system, whereas the OCI and the pollen/ovule ratio pointed towards a facultative xenogamous breeding system. Seed production was high (1,445 ± 132 seeds/plant); the seeds had potential longevity and were neutral photoblastic. One-year-old seeds germinated slightly later ( = 2.6 ± 0.11 days) than 2-year-old seeds ( = 1.9 ± 0.02 days), both synchronously (IS_1yr = 0.88 ± 0.03 and IS_2yr = 0.82 ± 0.02). Germination percentage for 1-year-old seeds was lower (55.33 ± 4.40%) than that of 2-year-old seeds (94.18 ± 0.59%), suggesting a potential longevity of the seeds in an optimal environment. Reproductive characteristics, such as wide reproductive period, mixed breeding system, copious seed production, seeds with potential longevity, and quick and synchronic germination in different light conditions, favor the invasive capacity of Leonotis nepetifolia.     

Developing a culture of safety in biomedical research training

The National Institute of General Medical Sciences (NIGMS) at the U.S. National Institutes of Health (NIH) is committed to supporting the safety of the nation’s biomedical research and training environments. Institutional training grants affect many trainees and can have a broad influence across their parent institutions, making them good starting points for our initial efforts to promote the development and maintenance of robust cultures of safety at U.S. academic institutions. In this Perspective, we focus on laboratory safety, although many of the strategies we describe for improving laboratory safety are also applicable to other forms of safety including the prevention of harassment, intimidation, and discrimination. We frame the problem of laboratory safety using a number of recent examples of tragic accidents, highlight some of the lessons that have been learned from these and other events, discuss what NIGMS is doing to address problems related to laboratory safety, and outline steps that institutions can take to improve their safety cultures.

All new funding opportunity announcements (FOAs) for training programs supported by the National Institute of General Medical Sciences (NIGMS) contain the expectation that the programs will promote “inclusive, safe and supportive scientific and training environments.” In this context, the word “safe” refers to several aspects of safety. First, we mean an environment free from harassment and intimidation, in which everyone participating is treated in a respectful and supportive manner, optimized for productive learning and research. We also mean that institutions should ensure that their campuses are as safe as possible so that individuals can focus on their studies and research. Finally, we mean safety in the laboratory and clinical spaces. In this Perspective, we focus on this last issue and describe some of the approaches NIGMS is taking to help the biomedical research community move toward an enhanced culture of safety in which core values and the behaviors of leadership, principal investigators (PIs), research staff, and trainees emphasize safety over competing goals.     

COVID-19 and “natural” experiments arising from physical distancing: a hypothetical case study from chronobiology

ABSTRACT

With countless “natural” experiments triggered by the COVID-19-associated physical distancing, one key question comes from chronobiology: “When confined to homes, how does the reduced exposure to natural daylight arising from the interruption of usual outdoor activities plus lost temporal organization ordinarily provided from workplaces and schools affect the circadian timing system (the internal 24 h clock) and, consequently, health of children and adults of all ages?” Herein, we discuss some ethical and scientific facets of exploring such natural experiments by offering a hypothetical case study of circadian biology.     

Competition at the soybean V6 stage affects root morphology and biochemical composition

• The experiment was conducted in the 2016/17 crop season in a greenhouse at Passo Fundo University, Brazil. We hypothesised that the morphological characteristics and biochemical and anatomical composition of soybean roots and shoots, when competing with weeds during different growth periods, are negatively affected, so current concepts of competition between plants should also consider changes in plant roots.
• The soybean cultivar P 95R51 and horseweed (Conyza bonariensis) were used. The treatments consisted of the presence or absence of weeds during different coexistence periods of soybean with horseweed. The periods were V0–V3, V0–V6, V0–R2, V3–R6, V6–R6 and R2–R6, where V0 was the date of soybean sowing and V3, V6, R2 and R6 were phenological stages of the crop. Two fresh roots were used to examine morphological traits. Four roots were used for quantification of dry matter and secondary metabolites.
• Root length was reduced by 21%, 14% and 20% when competing with a weed in the V0–V3, V0–V6 and R2–R6 coexistence periods, respectively. Total phenol content in the V0–V6 and V0–R2 periods was reduced when plants were in competition with weeds; a similar trend was found for flavonoids in the V0–V6 period.
• Soybean–horseweed competition from crop emergence to the V6 stage, in general, affects shoot and root morphological traits and the biochemical composition of the soybean roots. The presence of horseweed at the V3, V6 and R2 stages does not negatively alter the traits evaluated. Root anatomical composition is not modified during all coexistence periods with horseweed.

     

Spliceosome-targeted therapies trigger an antiviral immune response in triple-negative breast cancer

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The antigenic anatomy of SARS-CoV-2 receptor binding domain

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Discovery and functional interrogation of SARS-CoV-2 RNA-host protein interactions

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BET inhibition blocks inflammation-induced cardiac dysfunction and SARS-CoV-2 infection

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