Sleep and Sleepiness among Working and Non‐Working High School Evening Students

The aim of this study was to evaluate patterns of sleepiness, comparing working and non‐working students. The study was conducted on high school students attending evening classes (19:00–22:30 h) at a public school in São Paulo, Brazil. The study group consisted of working (n=51) and non‐working (n=41) students, aged 14–21 yrs. The students answered a questionnaire about working and living conditions and reported health symptoms and diseases. For seven consecutive days, actigraphy measurements were recorded, and the students also filled in a sleep diary. Sleepiness ratings were given six times per day, including upon waking and at bedtime, using the Karolinska Sleepiness Scale. Statistical analyses included three‐way ANOVA and t‐test. The mean sleep duration during weekdays was shorter among workers (7.2 h) than non‐workers (8.8 h) (t=4.34; p<.01). The mean duration of night awakenings was longer among workers on Tuesdays and Wednesdays (28.2 min) and shorter on Mondays (24.2 min) (t=2.57; p=.03). Among workers, mean napping duration was longer on Mondays and Tuesdays (89.9 min) (t=2.27; p=.03) but shorter on Fridays and Sundays (31.4 min) (t=3.13; p=.03). Sleep efficiency was lower on Fridays among non‐workers. Working students were moderately sleepier than non‐workers during the week and also during class on specific days: Mondays (13:00–15:00 h), Wednesdays (19:00–22:00 h), and Fridays (22:00–00:59 h). The study found that daytime sleepiness of workers is moderately higher in the evening. This might be due to a work effect, reducing the available time for sleep and shortening the sleep duration. Sleepiness and shorter sleep duration can have a negative impact on the quality of life and school development of high school students.     

Structure and function of potassium channels in plants: some inferences about the molecular origin of inward rectification in KAT1 channels (Review)

Potassium channels in plants play a variety of important physiological roles including K⁺ uptake into roots, stomatal and leaf movements, and release of K⁺ into the xylem. This review summarizes current knowledge about a class of plant genes whose products are K⁺ channel-forming proteins. Potassium channels of this class belong to a superfamily characterized by six membrane-spanning domains (S1-6), a positively charged S4 domain and a region between the S5 and S6 segments that forms the channel selectivity filter. These channels are voltage dependent, which means the membrane potential modifies the probability of opening (P_o). However, despite these channels sharing the same topology as the outward-rectifying K⁺ channels, which are activated by membrane depolarization, some plant K⁺ channels such as KAT1/2 and KST1 open with hyperpolarizing voltages. In outward-rectifying K⁺ channels, the change in P_o is achieved through a voltage sensor formed by the S4 segment that detects the voltage transferring its energy to the gate that controls pore opening. This coupling is achieved by an outward displacement of the charges contained in S4. In KAT1, most of the results indicate that S4 is the voltage sensor. However, how the movement of S4 leads to opening remains unanswered. On the basis of recent data, we propose here that in plant-inward rectifiers an inward movement of S4 leads to channel opening and that the difference between it and outward-rectifying channels resides in the mechanism that couples gating charge displacement with pore opening.     

Revealing hidden plant diversity in arid environments

Estimating total plant diversity in extreme or hyperarid environments can be challenging, as adaptations to pronounced climate variability include evading prolonged stress periods through seeds or specialized underground organs. Short‐term surveys of these ecosystems are thus likely poor estimators of actual diversity. Here we develop a multimethod strategy to obtain a more complete understanding of plant diversity from a community in the Atacama Desert. We explicitly test environmental DNA‐based techniques (eDNA) to see if they can reveal the observed and ‘hidden' (dormant or locally rare) species. To estimate total plant diversity, we performed long‐term traditional surveys during eight consecutive years, including El Niño and La Niña events, we then analyzed eDNA from soil samples using high‐throughput sequencing. We further used soil pollen analysis and soil seed bank germination assays to identify ‘hidden' species. Each approach offers different subsets of current biodiversity at different taxonomic, spatial and temporal resolution, with a total of 92 taxa identified along the transect. Traditional field surveys identified 77 plant species over eight consecutive years. Observed community composition greatly varies interannually, with only 22 species seen every year. eDNA analysis revealed 37 taxa, eight of which were ‘hidden' in our field surveys. Soil samples contain a viable seed bank of 21 taxa. Soil pollen (27 taxa) and eDNA analysis show affinities with vegetation at the landscape scale but a weak relationship to local plot diversity. Multimethod approaches (including eDNA) in deserts are valuable tools that add to a comprehensive assessment of biodiversity in such extreme environments, where using a single method or observations over a few years is insufficient. Our results can also explain the resilience of Atacama plant communities as ‘hidden' taxa may have been active in the recent past or could even emerge in the future as accelerated global environmental change continues unabated.     

Fatty Acid Diversity is Not Associated with Neutral Genetic Diversity in Native Populations of the Biodiesel Plant Jatropha curcas L.

Jatropha curcas L. (Euphorbiaceae) is a shrub native to Mexico and Central America, which produces seeds with a high oil content that can be converted to biodiesel. The genetic diversity of this plant has been widely studied, but it is not known whether the diversity of the seed oil chemical composition correlates with neutral genetic diversity. The total seed oil content, the diversity of profiles of fatty acids and phorbol esters were quantified, also, the genetic diversity obtained from simple sequence repeats was analyzed in native populations of J. curcas in Mexico. Using the fatty acids profiles, a discriminant analysis recognized three groups of individuals according to geographical origin. Bayesian assignment analysis revealed two genetic groups, while the genetic structure of the populations could not be explained by isolation‐by‐distance. Genetic and fatty acid profile data were not correlated based on Mantel test. Also, phorbol ester content and genetic diversity were not associated. Multiple linear regression analysis showed that total oil content was associated with altitude and seasonality of temperature. The content of unsaturated fatty acids was associated with altitude. Therefore, the cultivation planning of J. curcas should take into account chemical variation related to environmental factors.     

No evidence for homosubtypic immunity of influenza H3 in Mallards following vaccination in a natural experimental system

The Mallard (Anas platyrhynchos) is an important reservoir species for influenza A viruses (IAV), and in this host, prevalence and virus diversity are high. Studies have demonstrated the presence of homosubtypic immunity, where individuals are unlikely to be reinfected with the same subtype within an autumn season. Further, evidence for heterosubtypic immunity exists, whereby immune responses specific for one subtype offer partial or complete protection against related HA subtypes. We utilized a natural experimental system to determine whether homo‐ or heterospecific immunity could be induced following experimental vaccination. Thirty Mallards were vaccinated with an inactivated H3, H6 or a sham vaccine and after seroconversion were exposed to naturally infected wild conspecifics. All ducks were infected within 2 days and had both primary and secondary infections. Overall, there was no observable difference between groups; all individuals were infected with H3 and H10 IAV. At the cessation of the experiment, most individuals had anti‐NP antibodies and neutralizing antibodies against H10. Not all individuals had H3 neutralizing antibodies. The isolated H3 IAVs revealed genetic dissimilarity to the H3 vaccine strain, specifically substitutions in the vicinity of the receptor‐binding site. There was no evidence of vaccine‐induced homosubtypic immunity to H3, a likely result of both a poor H3 immune response in the ducks and H3 immune escape. Likewise, there was no observed heterosubtypic protection related to H6 vaccination. This study highlights the need for experimental approaches to assess how exposure to pathogens and resulting immune processes translates to individual and population disease dynamics.     

A new species and first record of Androdeloscia (Oniscidea: Philosciidae) from Colombia

The genus Androdeloscia includes 24 Neotropical species distributed in Central and South America. This study describes the new species Androdeloscia colombiana sp. nov. from El Chorro, Soplaviento, and from the Botanical Garden Guillermo Piñeres, Turbaco, Bolívar, Colombia. This is the first record of the genus in Colombia.

http://zoobank.org/urn:lsid:zoobank.org:pub:AEA56E26-1F6D-4DDA-BA02-D73DE9FAD198     

Plasmid-Encoded Anthranilate Synthase (TrpEG) in Buchnera aphidicola from Aphids of the Family Pemphigidae

Buchnera aphidicola is an obligate intracellular symbiont of aphids. One of its proposed functions is the synthesis of essential amino acids, nutrients required by aphids but deficient in their diet of plant phloem sap. The genetic organization of the tryptophan pathway in Buchnera from proliferous aphids of the family Aphididae has previously been shown to reflect a capacity to overproduce this essential amino acid (C.-Y. Lai, L. Baumann, and P. Baumann, Proc. Natl. Acad. Sci. USA 91:3819–3823, 1994). This involved amplification of the genes for the first enzyme in the pathway, anthranilate synthase (TrpEG), on a low-copy-number plasmid. Here we report on the finding and molecular characterization of TrpEG-encoding plasmids in Buchnera from aphids of the distantly related family Pemphigidae. Buchnera from Tetraneura caerulescens contained a 3.0-kb plasmid (pBTc2) that carried a single copy of trpEG and resembled trpEG plasmids of Buchnera from the Aphididae. The second plasmid (pBPs2), isolated from Buchnera of Pemphigus spyrothecae, contained a different replicon. It consisted of a putative origin of replication containing iterons and an open reading frame, designated repAC, which showed a high similarity to the gene encoding the replication initiation protein RepA of the RepA/C replicon from the broad-host-range IncA/C group of plasmids. The plasmid population was heterogeneous with respect to the number of tandem repeats of a 1.8-kb unit carrying repAC₁, trpG, and remnants of trpE. The two principal forms consisted of either five or six copies of this repeat and a single-copy region carrying repAC₂, the putative origin of replication, and trpE. The unexpected finding of elements of the RepA/C replicon in previously characterized trpEG plasmids from Buchnera of the Aphididae suggests that a replacement of replicons has occurred during the evolution of these plasmids, which may point to a common ancestry for all Buchnera trpEG amplifications.     

Multiple Sources of Introduction of North American Arabidopsis thaliana from across Eurasia

Large-scale movement of organisms across their habitable range, or migration, is an important evolutionary process that can shape genetic diversity and influence the adaptive spread of alleles. Although human migrations have been studied in great detail with modern and ancient genomes, recent anthropogenic influence on reducing the biogeographical constraints on the migration of nonnative species has presented opportunities in several study systems to ask the questions about how repeated introductions shape genetic diversity in the introduced range. We present an extensive overview of population structure of North American Arabidopsis thaliana by studying a set of 500 whole-genome sequenced and over 2,800 RAD-seq genotyped individuals in the context of global diversity represented by Afro-Eurasian genomes. We use methods based on haplotype and rare-allele sharing as well as phylogenetic modeling to identify likely sources of introductions of extant N. American A. thaliana from the native range in Africa and Eurasia. We find evidence of admixture among the introduced lineages having increased haplotype diversity and reduced mutational load. We also detect signals of selection in immune-system-related genes that may impart qualitative disease resistance to pathogens of bacterial and oomycete origin. We conclude that multiple introductions to a nonnative range can rapidly enhance the adaptive potential of a colonizing species by increasing haplotypic diversity through admixture. Our results lay the foundation for further investigations into the functional significance of admixture.     

Comparative genomics reveals new functional insights in uncultured MAST species

Heterotrophic lineages of stramenopiles exhibit enormous diversity in morphology, lifestyle, and habitat. Among them, the marine stramenopiles (MASTs) represent numerous independent lineages that are only known from environmental sequences retrieved from marine samples. The core energy metabolism characterizing these unicellular eukaryotes is poorly understood. Here, we used single-cell genomics to retrieve, annotate, and compare the genomes of 15 MAST species, obtained by coassembling sequences from 140 individual cells sampled from the marine surface plankton. Functional annotations from their gene repertoires are compatible with all of them being phagocytotic. The unique presence of rhodopsin genes in MAST species, together with their widespread expression in oceanic waters, supports the idea that MASTs may be capable of using sunlight to thrive in the photic ocean. Additional subsets of genes used in phagocytosis, such as proton pumps for vacuole acidification and peptidases for prey digestion, did not reveal particular trends in MAST genomes as compared with nonphagocytotic stramenopiles, except a larger presence and diversity of V-PPase genes. Our analysis reflects the complexity of phagocytosis machinery in microbial eukaryotes, which contrasts with the well-defined set of genes for photosynthesis. These new genomic data provide the essential framework to study ecophysiology of uncultured species and to gain better understanding of the function of rhodopsins and related carotenoids in stramenopiles.Subject terms: Genomics, Microbiology