Further Evidence for the Influence of Photoperiod at Birth on Chronotype in a Sample of German Adolescents

Individuals differ in their circadian preferences (chronotype). There is evidence in the literature to support a season-of-birth effect on chronotype but the evidence is not convincing. In part, the relationship is obscured by a number of methodological differences between studies, including the measures used to define morningness, the way in which the seasons were categorized, and the sample size. This study adds to the literature in several ways. First, we adopt a new approach to categorizing the photoperiod rather than the calendar season; thus we prefer to use the term photoperiod at birth. Second, we used two measures of morningness. Third, we used a large and homogeneous German sample. The results show that adolescents (n?=?2905) born during the increasing photoperiod (Feb–Apr) had a significantly later midpoint of sleep (MSFsc) than those born during the decreasing photoperiod (Aug–Oct). A similar pattern was found for the Composite Scale of Morningness (CSM). Furthermore, both measures of chronotype demonstrated a significant quadratic function over a 1-yr cycle. When looking at each of six consecutive years separately, the Composite Scale of Morningness suggests a cosine rhythm linked to increasing and decreasing photoperiods that becomes weaker in amplitude with increasing age. Despite the strengths in our study, the effect of photoperiod at birth on chronotype remains small. Future studies may require larger sample sizes, may need to explore how neonatal light exposure modulates chronotype, and may need to track how puberty and adolescent lifestyle habits mask the photoperiod effect. (Author correspondence: vollmer@ph-heidelberg.de)     

UniEuk: Time to Speak a Common Language in Protistology!

Universal taxonomic frameworks have been critical tools to structure the fields of botany, zoology, mycology, and bacteriology as well as their large research communities. Animals, plants, and fungi have relatively solid, stable morpho‐taxonomies built over the last three centuries, while bacteria have been classified for the last three decades under a coherent molecular taxonomic framework. By contrast, no such common language exists for microbial eukaryotes, even though environmental ‘‐omics’ surveys suggest that protists make up most of the organismal and genetic complexity of our planet's ecosystems! With the current deluge of eukaryotic meta‐omics data, we urgently need to build up a universal eukaryotic taxonomy bridging the protist ‐omics age to the fragile, centuries‐old body of classical knowledge that has effectively linked protist taxa to morphological, physiological, and ecological information. UniEuk is an open, inclusive, community‐based and expert‐driven international initiative to build a flexible, adaptive universal taxonomic framework for eukaryotes. It unites three complementary modules, EukRef, EukBank, and EukMap, which use phylogenetic markers, environmental metabarcoding surveys, and expert knowledge to inform the taxonomic framework. The UniEuk taxonomy is directly implemented in the European Nucleotide Archive at EMBL‐EBI, ensuring its broad use and long‐term preservation as a reference taxonomy for eukaryotes.     

Early dinner or “dinner like a pauper”: Evidence,the habitual time of the largest meal of the day – dinner – is predisposing to severe COVID-19 outcome – death

ABSTRACT

COVID-19 and metabolic syndrome are devastating pandemics. Effective control of metabolic parameters and their dysfunction may help prevent or minimize the acute and devastating effects of SARS-CoV-2 by reducing the local inflammatory response and blocking the entry of the virus into cells. With such consideration in mind, we gathered data from dietary surveys conducted in nine European countries to explore the relationship between actual clock hour of the large dinner meal and also interval in minutes between it and sunset in the respective countries and death rate above the median rate of per one million people as an index of mortality due to COVID-19 infection. Clock time of the dinner meal varied between 16:00 and 21:00 h across the European counties sampled, and the correlation between dinner mealtime and death rate was strongly correlated, R = 0.7991 (two-tailed p = 0.0098), with R ² explaining 63% of the variation within the data. This strong linear positive correlation indicates that the later the clock time of the dinner meal, the higher is the death rate (and vice versa). The relationship between meal timing in reference to sunset, utilized as a gross surrogate marker of the activity/rest synchronizer of circadian rhythms, and death rate was negative and even slightly stronger, R = ?0.8025 (two-tailed p = 0.0092), with R ² explaining 64% of the variation within the data. This strong linear negative correlation indicates that the shorter the interval between the dinner meal and sunset, i.e., the closer the time of the largest meal of the day to bedtime, the greater is the death rate (and vice versa). Our preliminary approach to nighttime eating, in terms of the day’s largest caloric intake, as a risk factor for the predisposing conditions of obesity, metabolic syndrome, type 2 diabetes, and other commonly associated comorbidities of being overweight, and death from COVID-19 infection reveals strong correlation with the time of the dinner meal, both in terms of its actual clock and circadian time.     

Cell body and flagellar agglutinins in Chlamydomonas reinhardtii: the cell body plasma membrane is a reservoir for agglutinins whose migration to the flagella is regulated by a functional barrier

Fertilization in Chlamydomonas reinhardtii is initiated when gametes of opposite mating types adhere to each other via adhesion molecules (agglutinins) on their flagella. Adhesion leads to loss of active agglutinins from the flagella and recruitment of new agglutinins from a pool associated with the cell body. We have been interested in determining the precise cellular location of the pool and learning more about the relationship between agglutinins in the two domains. In the studies reported here we describe methods for purification of mt+ cell body agglutinins by use of ammonium sulfate precipitation, chromatography (molecular sieve, ion exchange, and hydrophobic interaction), and sucrose gradient centrifugation. About 90% of the total agglutinins were associated with the cell body and the remainder were on the flagella. Cell body agglutinins were indistinguishable from mt+ flagellar agglutinins by SDS-PAGE, elution properties on a hydrophobic interaction column, and in sedimentation properties on sucrose gradients. The nonadhesiveness of cell bodies suggested that the cell body agglutinins would be intracellular, but our results are not consistent with this interpretation. We have demonstrated that brief trypsin treatment of deflagellated gametes destroyed all of the cell body agglutinins and, in addition, we showed that the cell body agglutinins were accessible to surface iodination. These results indicated that C. reinhardtii agglutinins have a novel cellular disposition: active agglutinins, representing approximately 10% of the total cellular agglutinins, are found only on the flagella, whereas the remaining 90% of these molecules are on the external surface of the cell body plasma membrane in a nonfunctional form. This segregation of cell adhesion molecules into distinct membrane domains before gametic interactions has been demonstrated in sperm of multicellular organisms and may be a common mechanism for sequestering these critical molecules until gametes are activated for fusion. In experiments in which surface-iodinated cell bodies were permitted to regenerate new flagella, we found that the agglutinins (as well as the 350,000 Mr, major flagellar membrane protein) on the newly regenerated flagella were iodinated. These results indicate that proteins destined for the flagella can reside on the external surface of the cell body plasma membrane and are recruited onto newly forming flagella as well as onto preexisting flagella during fertilization.     

Contribution of Dysferlin Deficiency to Skeletal Muscle Pathology in Asymptomatic and Severe Dystroglycanopathy Models: Generation of a New Model for Fukuyama Congenital Muscular Dystrophy

Defects in dystroglycan glycosylation are associated with a group of muscular dystrophies, termed dystroglycanopathies, that include Fukuyama congenital muscular dystrophy (FCMD). It is widely believed that abnormal glycosylation of dystroglycan leads to disease-causing membrane fragility. We previously generated knock-in mice carrying a founder retrotransposal insertion in fukutin, the gene responsible for FCMD, but these mice did not develop muscular dystrophy, which hindered exploring therapeutic strategies. We hypothesized that dysferlin functions may contribute to muscle cell viability in the knock-in mice; however, pathological interactions between glycosylation abnormalities and dysferlin defects remain unexplored. To investigate contributions of dysferlin deficiency to the pathology of dystroglycanopathy, we have crossed dysferlin-deficient dysferlin ^sjl/sjl mice to the fukutin-knock-in fukutin ^Hp/− and Large-deficient Large ^myd/myd mice, which are phenotypically distinct models of dystroglycanopathy. The fukutin ^Hp/− mice do not show a dystrophic phenotype; however, (dysferlin ^sjl/sjl: fukutin ^Hp/−) mice showed a deteriorated phenotype compared with (dysferlin ^sjl/sjl: fukutin ^Hp/+) mice. These data indicate that the absence of functional dysferlin in the asymptomatic fukutin ^Hp/− mice triggers disease manifestation and aggravates the dystrophic phenotype. A series of pathological analyses using double mutant mice for Large and dysferlin indicate that the protective effects of dysferlin appear diminished when the dystrophic pathology is severe and also may depend on the amount of dysferlin proteins. Together, our results show that dysferlin exerts protective effects on the fukutin ^Hp/− FCMD mouse model, and the (dysferlin ^sjl/sjl: fukutin ^Hp/−) mice will be useful as a novel model for a recently proposed antisense oligonucleotide therapy for FCMD.     

In Vivo Release of Endogenous Amino Acids from the Rat Striatum: Further Evidence for a Role of Glutamate and Aspartate in Corticostriatal Neurotransmission

By means of the push-pull cannula method, the outflow of endogenous amino acids was studied in the striatum of halothane-anesthetized rats. Addition of K+ ions (30 mM for 4 min) to the superfusion fluid increased the release of aspartate (+116%), glutamate (+217%), taurine (+109%), and gamma-aminobutyric acid (GABA) (+429%) whereas a prolonged decrease in the outflow of glutamine (-28%) and a delayed reduction in the efflux of tyrosine (-25%) were observed. In the absence of Ca2+, the K+-induced release of aspartate, glutamate, and GABA was blocked whereas the K+-induced release of taurine was still present. Under these conditions, the decrease in glutamine efflux was reduced and that of tyrosine was abolished. Local application of tetrodotoxin (5 microM) decreased only the outflow of glutamate (-25%). One week following lesion of the ipsilateral sensorimotor cortex the spontaneous outflow of glutamine and of tyrosine was enhanced. Despite the lack of change in their spontaneous outflow, the K+-evoked release of aspartate and glutamate was less pronounced in lesioned than in control animals, whereas the K+-evoked changes in GABA and glutamine efflux were not modified. Our data indicate that the push-pull cannula method is a reliable approach for the study of the in vivo release of endogenous amino acids. In addition, they provide further evidence for a role for glutamate and aspartate as neurotransmitters of corticostriatal neurons.     

kakapo, a Gene Required for Adhesion Between and Within Cell Layers in Drosophila, Encodes a Large Cytoskeletal Linker Protein Related to Plectin and Dystrophin

Mutations in kakapo were recovered in genetic screens designed to isolate genes required for integrin-mediated adhesion in Drosophila. We cloned the gene and found that it encodes a large protein (>5,000 amino acids) that is highly similar to plectin and BPAG1 over the first 1,000–amino acid region, and contains within this region an α-actinin type actin-binding domain. A central region containing dystrophin-like repeats is followed by a carboxy domain that is distinct from plectin and dystrophin, having neither the intermediate filament-binding domain of plectin nor the dystroglycan/syntrophin-binding domain of dystrophin. Instead, Kakapo has a carboxy terminus similar to the growth arrest–specific protein Gas2. Kakapo is strongly expressed late during embryogenesis at the most prominent site of position-specific integrin adhesion, the muscle attachment sites. It is concentrated at apical and basal surfaces of epidermal muscle attachment cells, at the termini of the prominent microtubule bundles, and is required in these cells for strong attachment to muscles. Kakapo is also expressed more widely at a lower level where it is essential for epidermal cell layer stability. These results suggest that the Kakapo protein forms essential links among integrins, actin, and microtubules.     

Protein Turnover in Response to Transient Exposure to Exogenous Auxin is Necessary for Restoring Auxin Autotrophy in a Stressed Arachis hypogea Cell Culture

An auxin autotrophic Arachis hypogea cell culture was sensitive to stress treatments leading to water loss whereas the growth of its auxin-supplemented counterpart was unaffected under similar conditions. Here we show that an hour of transient auxin treatment in the post stress period was sufficient for restoring the auxin autotrophic growth potential of the stress driven quiescent Arachis cells. Qualitative proteome analysis revealed protein turnover to have a role in mediating auxin-originated signals in these cells. In consonance, MG132 a cell permeable inhibitor of the ubiquitin mediated protein turnover completely inhibited the auxin dependent growth restoration of the stressed Arachis cells. Thus protein turnover is a necessary downstream event in exogenous auxin mediated stress tolerance in Arachis cells.     

Characterization of Two Distinct Monoclonal Antibodies to Paired Helical Filaments: Further Evidence for Fetal-Type Phosphorylation of the τ in Paired Helical Filaments

Abstract: Two monoclonal antibodies C5 and M4 raised against Sarkosyl-insoluble paired helical filaments (PHF) specifically labeled fetal τ, but hardly labeled normal adult τ. C5 immunoreactivity was eliminated by alkaline phosphatase treatment at 37°C, whereas M4 reactivity could be removed only by the treatment at 67°C. Epitope analysis showed that C5 and M4 recognition sites are in residues 386–406 and 198–250, respectively, according to the numbering of the longest human τ isoform. Thus, the phosphorylation sites are located in the amino- and carboxyl-terminal portions of the microtubule-binding region. These two well-characterized monoclonals should be valuable in the identification of a protein kinase(s) that converts normal τ into PHF-τ.     

The Utility of the Swine Model to Assess Biological Rhythms and Their Characteristics during Different Stages of Residence in a Simulated Intensive Care Unit: A Pilot Study

The purpose of this pilot study was to explore the utility of the mammalian swine model under simulated intensive care unit (sICU) conditions and mechanical ventilation (MV) for assessment of the trajectory of circadian rhythms of sedation requirement, core body temperature (CBT), pulmonary mechanics (PM) and gas exchange (GE). Data were collected prospectively with an observational time-series design to describe and compare circadian rhythms of selected study variables in four swine mechanically ventilated for up to seven consecutive days. We derived the circadian (total variance explained by rhythms of τ between 20 and 28?h)/ultradian (total variance explained by rhythms of τ between 1 and <20?h) bandpower ratio to assess the robustness of circadian rhythms, and compare findings between the early (first 3 days) and late (subsequent days) sICU stay. All pigs exhibited statistically significant circadian rhythms (τ between 20 and 28?h) in CBT, respiratory rate and peripheral oxygen saturation, but circadian rhythms were detected less frequently for sedation requirement, spontaneous minute volume, arterial oxygen tension, arterial carbon dioxide tension and arterial pH. Sedation did not appear to mask the circadian rhythms of CBT, PM and GE. Individual subject observations were more informative than group data, and provided preliminary evidence that (a) circadian rhythms of multiple variables are lost or desynchronized in mechanically ventilated subjects, (b) robustness of circadian rhythm varies with subject morbidity and (c) healthier pigs develop more robust circadian rhythm profiles over time in the sICU. Comparison of biological rhythm profiles among sICU subjects with similar severity of illness is needed to determine if the results of this pilot study are reproducible. Identification of consistent patterns may provide insight into subject morbidity and timing of such therapeutic interventions as weaning from MV.     

The contribution of mistletoes to nutrient returns: Evidence for a critical role in nutrient cycling

Both nutrient cycling and nutrient relationships between mistletoe and host have been widely studied; yet it is unclear whether high nutrient concentrations commonly found in mistletoes affect rates of nutrient cycling. To address this question, we assessed 13 elements in the leaf litter of a temperate eucalypt forest in southern New South Wales, comparing concentrations from trees (Eucalyptus blakelyi, E. dwyeri, and E. dealbata) with and without the hemiparasitic mistletoe Amyema miquelii. Results were in accord with previous research on fresh leaves showing that concentrations of many elements were higher in the mistletoe than the host. This was not the case for all elements; most notably for N, where concentrations were significantly lower in the mistletoe. However, the return of all elements increased with mistletoe infection because of the combined effect of enrichment in mistletoe tissues and high rates of mistletoe litterfall. Annual returns of N and P in leaf litter increased by a factor of 1.65 and 3 respectively, with the greatest increase being for K by a factor of 43 in spring. These increased element returns were not significantly influenced by any changes in host leaf litter quality, as mistletoe infection was not found to affect host element concentrations. Mistletoe infection also altered the spatial and temporal distribution of element returns because of the patchy occurrence of mistletoes and extended period of mistletoe litterfall compared with the host. These findings provide a mechanistic explanation for the role of mistletoes as a keystone resource and, together with comparable results from root‐parasitic plants in boreal tundra and cool‐temperate grasslands, suggest that enhancing nutrient return rates may be a generalized property of parasitic plants.     

Effect of Sodium, Potassium, Calcium, Magnesium and Tetraethylammonium on the Transient Voltage Response to a Galvanostatic Step and of the Temperature on the Steady Membrane Conductance of Chara corallina: a Further Evidence for the Involvement of Potassium Channels in the Fast Time Variant Conductance

Homble F. 1985. Effect of sodium, potassium, calcium, magnesiumand tetraethylammonium on the transient voltage response toa galvanostatic step and of the temperature on the steady membraneconductance of Chara corallina: A further evidence for the involvementof potassium in the fast time variant conductance.—J.exp. Bot. 36: 1603–1611. Potassium channels of Chara corallina have an activation energyof 36±1 kJ mol^–1 and 50±2 kJ mol^–1at temperatures higher and lower than 15°C respectively.The fast time variant conductance property of potassium channelsis insensitive to sodium and magnesium ions and is depressedby the presence of calcium, potassium and tetraethylammoniumions. It is suggested that in Chara two different kinds of potassiumchannels exist, each kind being distinguished by their kineticsand their response to calcium and magnesium ions. Key words: —Chara corallina, membrane conductance, potassium channels, temperature     

The Expression Pattern of the Gene for NPK1 Protein Kinase Related to Mitogen-Activated Protein Kinase Kinase Kinase (MAPKKK) in a Tobacco Plant: Correlation with Cell Proliferation

Mitogen-activated protein kinase (MAPK) cascades consist ofmembers of three families of protein kinases: the MAPK family,the MAPK kinase family, and the MAPK kinase kinase (MAPKKK)family. Some of these cascades have been shown to play centralroles in the transmission of signals that control various cellularprocesses including cell proliferation. Protein kinase NPK1is a structural and functional tobacco homologue of MAPKKK,but its physiological function is yet unknown. In the presentstudy, we have investigated sites of expression of the NPK1gene in a tobacco plant and developmental and physiologicalcontrols of this expression. After germination, expression ofNPK1 was first detected in tips of a radicle and cotyledons,then in shoot and root apical meristems, surrounding tissuesof the apical meristems, primordia of lateral roots, and youngdeveloping organs. No expression was, however, observed in matureorgans. Incubation of discs from mature leaves of tobacco withboth auxin and cytokinin induced NPK1 expression before thedivision of cells. It was also induced at early stages of thedevelopment of primordia of lateral roots and adventitious roots.Thus, NPK1 expression appears to be tightly correlated withcell division or division competence. Even when an inhibitorof DNA synthesis was added during the germination or the inductionof lateral roots by auxin, NPK1 expression was detected. Theseresults showed that the NPK1 expression precedes DNA replication.We propose that NPK1 participates in a process involving thedivision of plant cells. (Received January 26, 1998; Accepted April 9, 1998)     

No mutual mate choice for quality in zebra finches: Time to question a widely held assumption

Studies of mate choice typically assume that individuals prefer high quality mates and select them based on condition‐dependent indicator traits. In species with biparental care, mutual mate choice is expected to result in assortative mating for quality. When assortment is not perfect, the lower quality pair members are expected to compensate by increased parental investment to secure their partner (positive differential allocation). This framework has been assumed to hold for monogamous species like the zebra finch (Taeniopygia guttata), but progress has been hampered by the difficulty to define individual quality. By combining multiple measures of causes (inbreeding, early nutrition) and consequences (ornaments, displays, fitness components) of variation in quality into a single principal component, we here show that quality variation can be quantified successfully. We further show that variation in quality indeed predicts individual pairing success, presumably because it reflects an individual's vigor or ability to invest in reproduction. However, despite high statistical power, we found no evidence for either assortative mating or for positive differential allocation. We suggest that zebra finch ornaments and displays are not sufficiently reliable for the benefits of choosiness to exceed the costs of competition for the putative best partner. To assess the generality of these findings unbiased quantification of signal honesty and preference strength is required, rather than selective reporting of significant results.     

Disorders of Transmission via a Peripheral Nerve Related to Experimental Diabetic Peripheral Neuropathy in Rats: Possibilities for Pharmacological Correction

We measured the conduction velocity (CV) of an excitation volley via the caudal nerve in intact rats and rats with streptozotocin-induced experimental diabetic polyneuropathy (ED PNP). We also tested the influence of four pharmacological agents (lipoic acid, N^G-nitro-L-arginine, alprostan, and pentoxifylline) on the CV via the above nerve under conditions of ED PNP. We found that the development of ED PNP in rats was accompanied by a considerable drop in the CV (to 50–40% of that in the control). Introduction of the above pharmacological agents exerted noticeable normalizing effects on the parameter under study; these effects were observed from the second week of treatment and lasted up to the end of the tests. Considering the mechanisms governing the effects of the above drugs, we discuss the role of disturbances in the systems of endogenous nitric oxide and prostaglandins in the development of experimental diabetes and ED PNP.Neirofiziologiya/Neurophysiology, Vol. 37, No. 1, pp. 74–79, January–February, 2005.     

Improved Methodology for Sensitive and Rapid Quantitative Proteomic Analysis of Adult‐Derived Mouse Microglia: Application to a Novel In Vitro Mouse Microglial Cell Model

Microglia, as the resident brain immune cells, can exhibit a broad range of activation phenotypes, which have been implicated in a multitude of central nervous system disorders. Current widely studied microglial cell lines are mainly derived from neonatal rodent brain that can limit their relevance to homeostatic function and disease‐related neuroimmune responses in the adult brain. Recently, an adult mouse brain‐derived microglial cell line has been established; however, a comprehensive proteome dataset remains lacking. Here, an optimization method for sensitive and rapid quantitative proteomic analysis of microglia is described that involves suspension trapping (S‐Trap) for efficient and reproducible protein extraction from a limited number of microglial cells expected from an adult mouse brain (≈300 000). Using a 2‐h gradient on a 75‐cm UPLC column with a modified data dependent acquisition method on a hybrid quadrupole‐Orbitrap mass spectrometer, 4855 total proteins have been identified where 4698 of which are quantifiable by label‐free quantitation with a median and average coefficient of variation (CV) of 6.7% and 10.6%, respectively. This dataset highlights the high depth of proteome coverage and related quantitation precision of the adult‐derived microglial proteome including proteins associated with several key pathways related to immune response. Data are available via ProteomeXchange with identifier PXD012006.     

Analysis of revertants of a ribosomal mutation in Podospora anserina: Evidence for new ribosomal mutations which confer hypersensitivity to paromomycin

This paper describes the analysis of cold-resistant revertants of a cold-sensitive mutant. Pm1-1 is a ribosomal mutation screened for its paromomycin resistance. Suppression of its cold sensitivity occurs with two kinds of external mutations localized in two different loci. One of them, PmB, is assumed to be a ribosomal gene. PmB mutations confer hypersensitivity to paromomycin in vivo as well as in vitro in a cell-free protein synthesis system.This work was supported by DGRST Grant MRM/P240 and NATO Grant 1637.     

Amyloid β-Mediated Oxidative and Metabolic Stress in Rat Cortical Neurons: No Direct Evidence for a Role for H2O2 Generation

Abstract: H₂O₂ and free radical-mediated oxidative stresses have been implicated in mediating amyloid β(1–40) [Aβ(1–40)] neurotoxicity to cultured neurons. In this study, we confirm that addition of the H₂O₂-scavenging enzyme catalase protects neurons in culture against Aβ-mediated toxicity; however, it does so by a mechanism that does not involve its ability to scavenge H₂O₂. Aβ-mediated elevation in intracellular H₂O₂ production is suppressed by addition of a potent H₂O₂ scavenger without any significant neuroprotection. Three intracellular biochemical markers of H₂O₂-mediated oxidative stress were unchanged by Aβ treatment: (a) glyceraldehyde-3-phosphate dehydrogenase activity, (b) hexose monophosphate shunt activity, and (c) glucose oxidation via the tricarboxylic acid cycle. Ionspray mass spectra of Aβ in the incubation medium indicated that Aβ itself is an unlikely source of reactive oxygen species. In this study we demonstrate that intracellular ATP concentration is compromised during the first 24-h exposure of neurons to Aβ. Our results challenge a pivotal role for H₂O₂ generation in mediating Aβ toxicity, and we suggest that impairment of energy homeostasis may be a more significant early factor in the neurodegenerative process.