Repercussions of the COVID-19 pandemic on athletes: a cross-sectional study

The COVID-19 pandemic has presented significant challenges and implications for the sports community. Thus, this study aimed to describe the prevalence of COVID-19 in Brazilian athletes and identify the epidemiological, clinical, athletic, life and health factors associated with the disease in these individuals. A cross-sectional study was performed involving 414 athletes from 22 different sports using an online questionnaire from August to November 2020. The association between the athletes’ characteristics and COVID-19 was evaluated using a logistic regression model. The prevalence of COVID-19 was 8.5%, although only 40% of athletes reported having been tested. Being under 27 years of age (3-fold), having children (~5-fold), having a teammate test positive for COVID-19 (2.5-fold), and smoking (14-fold) were associated with a possible higher risk of disease. Almost 20% of athletes self-reported musculoskeletal injuries during the period of the pandemic that was studied. Athletes with a university education (P = 0.02), a profession other than sports (P < 0.001), those from a low-income family (P = 0.01), and public health system users (P = 0.04) were significantly less frequently tested for COVID-19, whereas international competitors, athletes who received a wage, and athletes who had a teammate who tested positive for COVID-19 were 2-, 3-, and 15-fold more likely to be tested for COVID-19, respectively. Approximately 26% of the athletes who tested negative or were untested reported more than three characteristic COVID-19 symptoms, and 11% of athletes who tested positive for COVID-19 were asymptomatic. The identification of modifiable (have children, smoking, and teammates positively tested) and non-modifiable (age under 27 years) factors related to COVID-19 in athletes can contribute to implementing surveillance programmes to decrease the incidence of COVID-19 in athletes and its negative impacts in sports.     

Fungal phytochrome chromophore biosynthesis at mitochondria

Mitochondria are essential organelles because of their function in energy conservation. Here, we show an involvement of mitochondria in phytochrome‐dependent light sensing in fungi. Phytochrome photoreceptors are found in plants, bacteria, and fungi and contain a linear, heme‐derived tetrapyrrole as chromophore. Linearization of heme requires heme oxygenases (HOs) which reside inside chloroplasts in planta. Despite the poor degree of conservation of HOs, we identified two candidates in the fungus Alternaria alternata. Deletion of either one phenocopied phytochrome deletion. The two enzymes had a cooperative effect and physically interacted with phytochrome, suggesting metabolon formation. The metabolon was attached to the surface of mitochondria with a C‐terminal anchor (CTA) sequence in HoxA. The CTA was necessary and sufficient for mitochondrial targeting. The affinity of phytochrome apoprotein to HoxA was 57,000‐fold higher than the affinity of the holoprotein, suggesting a “kiss‐and‐go” mechanism for chromophore loading and a function of mitochondria as assembly platforms for functional phytochrome. Hence, two alternative approaches for chromophore biosynthesis and insertion into phytochrome evolved in plants and fungi.     

Genome-wide analyses of light-regulated genes in Aspergillus nidulans reveal a complex interplay between different photoreceptors and novel photoreceptor functions

Fungi sense light of different wavelengths using blue-, green-, and red-light photoreceptors. Blue light sensing requires the “white-collar” proteins with flavin as chromophore, and red light is sensed through phytochrome. Here we analyzed genome-wide gene expression changes caused by short-term, low-light intensity illumination with blue-, red- or far-red light in Aspergillus nidulans and found that more than 1100 genes were differentially regulated. The largest number of up- and downregulated genes depended on the phytochrome FphA and the attached HOG pathway. FphA and the white-collar orthologue LreA fulfill activating but also repressing functions under all light conditions and both appear to have roles in the dark. Additionally, we found about 100 genes, which are red-light induced in the absence of phytochrome, suggesting alternative red-light sensing systems. We also found blue-light induced genes in the absence of the blue-light receptor LreA. We present evidence that cryptochrome may be part of this regulatory cue, but that phytochrome is essential for the response. In addition to in vivo data showing that FphA is involved in blue-light sensing, we performed spectroscopy of purified phytochrome and show that it responds indeed to blue light.     

Regulation of glutamate dehydrogenase in Bacillus subtilis.

The activity of the nicotinamide adenine dinucleotide-dependent glutamate dehydrogenase in Bacillus subtilis was influenced by the carbon source, but not the nitrogen source, in the growth medium. The highest specific activity for this enzyme was found when B. subtilis was grown in a minimal or rich medium that contained glutamate as the carbon source. It is proposed that glutamate dehydrogenase serves a catabolic function in the metabolism of glutamate, is induced by glutamate, and is subject to catabolite repression.     

Generation and Properties of a Streptococcus pneumoniae Mutant Which Does Not Require Choline or Analogs for Growth

A mutant (JY2190) of Streptococcus pneumoniae Rx1 which had acquired the ability to grow in the absence of choline and analogs was isolated. Lipoteichoic acid (LTA) and wall teichoic acid (TA) isolated from the mutant were free of phosphocholine and other phosphorylated amino alcohols. Both polymers showed an unaltered chain structure and, in the case of LTA, an unchanged glycolipid anchor. The cell wall composition was also not altered except that, due to the lack of phosphocholine, the phosphate content of cell walls was half that of the parent strain. Isolated cell walls of the mutant were resistant to hydrolysis by pneumococcal autolysin (N-acetylmuramyl-l-alanine amidase) but were cleaved by the muramidases CPL and cellosyl. The lack of active autolysin in the mutant cells became apparent by impaired cell separation at the end of cell division and by resistance against stationary-phase and penicillin-induced lysis. As a result of the absence of choline in the LTA, pneumococcal surface protein A (PspA) was no longer retained on the cytoplasmic membrane. During growth in the presence of choline, which was incorporated as phosphocholine into LTA and TA, the mutant cells separated normally, did not release PspA, and became penicillin sensitive. However, even under these conditions, they did not lyse in the stationary phase, and they showed poor reactivity with antibody to phosphocholine and an increased release of C-polysaccharide from the cell. In contrast to ethanolamine-grown parent cells (A. Tomasz, Proc. Natl. Acad. Sci. USA 59:86–93, 1968), the choline-free mutant cells retained the capability to undergo genetic transformation but, compared to Rx1, with lower frequency and at an earlier stage of growth. The properties of the mutant could be transferred to the parent strain by DNA of the mutant.Pneumococci differ from other gram-positive bacteria in that their lipoteichoic acid (LTA) and wall teichoic acid (TA) have the same chain structure which is, moreover, unusually complex (Fig. ​(Fig.1):1): glycerophosphate is replaced by ribitol phosphate (7), and between the ribitol phosphate residues a tetrasaccharide is intercalated (23). It contains d-glucose, 2-acetamido-4-amino-2,4,6-trideoxy-d-galactose (AATGal), and two N-acetyl-d-galactosaminyl residues, one or both of which carry a phosphocholine residue at O-6 (references 3 and 12 and this report). Open in a separate windowFIG. 1Pneumococcal TA and LTA. As shown, in strain R6 most of the repeats carry two phosphocholine residues each, at O-6 of the N-acetyl-d-galactosaminyl residues (3, 12). In strain Rx1 and Rx1/AL⁻, most repeats contain one phosphocholine residue (this report) attached to O-6 of the non-ribitol-linked galactosaminyl residue (14).Pneumococci are not able to synthesize the choline required for the synthesis of these substituents. Moreover, choline is an essential growth factor (2, 30) but can be substituted in this function by nutritional ethanolamine (EA) (38). Phosphoethanolamine is incorporated into LTA and TA in place of phosphocholine (14), but it cannot replace phosphocholine functionally. Phosphocholine-substituted LTA serves to anchor pneumococcal surface protein A (PspA) to the outer layer of the cytoplasmic membrane, with choline-mediated interaction between membrane-associated LTA and the C-terminal repeat region of PspA. In EA-grown bacteria, PspA is no longer retained and is released into the surrounding medium (45). Phosphocholine substituents also play an essential role for the activity of the major pneumococcal autolysin, an N-acetylmuramyl-l-alanine amidase (38). This protein possesses a choline-binding C-terminal domain that is essential for activity but, unlike PspA, is not essential for retention on the pneumococcal cell surface (16, 32). Binding of phosphocholine-substituted LTA to this domain results in potent inhibition of the amidase (21). The inhibitory property is dependent on the micellar structure of LTA (13) and lost by deacylation (5). Phosphocholine-substituted LTA may also participate in the transport of the amidase through the cytoplasmic membrane from the cytosol (5), the location of its synthesis (15). It additionally effects the conversion of the inactive E form of the enzyme into the active C form (5). This conversion is likewise effected by the choline residues of cell wall-linked TA (33, 39). Furthermore, binding of the amidase to the choline residues of TA is prerequisite for the hydrolysis of cell walls by the enzyme (18, 22). It should be noted that the amidase is not essential for growth. Though the enzyme is completely inactive in EA grown cells, the growth rate is not affected. However, cell separation is impaired, and there is a loss of stationary-phase and penicillin-induced cell lysis (38, 40), as well as a loss of genetic transformation (38). After insertional inactivation of the autolysin gene (lytA), the autolysin-deficient mutants (Lyt⁻) grew normally (31) and did not even show impeded cell separation (41).In this report, we describe a mutant which acquired the ability to grow in the absence of choline and analogs. Except for the observation that [³H]choline-substituted LTA is not a precursor of [³H]choline-substituted TA (6), nothing is known about the biosyntheses of pneumococcal LTA and TA and the stage of biosynthesis at which phosphocholine is incorporated. Since the absence of choline incorporation might affect the structure of LTA and TA as well as the composition of cell walls, we included relevant analyses in our study.(A preliminary report of this work was presented in an overview on pneumococcal LTA and TA at the International Meeting on the Molecular Biology of Streptococcus pneumoniae and Its Diseases, Oeiras, Portugal, September 24 to 29, 1996 [10].)     

Expression and biochemical characterization of human immunodeficiency virus type 1 nef gene product.

nef genes from human immunodeficiency virus type 1 isolates BH10 and LAV1 (lymphadenopathy-associated virus type 1) were expressed in Escherichia coli under the deo operon promoter. The two proteins found in the soluble compartment of the bacterial lysate were purified by ion-exchange column chromatography to apparent homogeneity. Determination of the amino-terminal sequence revealed glycine as the first amino acid in the Nef protein, indicating removal of the initiator methionine during expression in E. coli. Under native conditions, the recombinant Nef protein is a monomer of 23 kilodaltons. In denaturing polyacrylamide gels, however, BH10 and LAV1 Nef proteins migrate as 28 and 26 kilodaltons, respectively. GTP binding and GTPase activity were monitored during Nef protein purification. These activities did not copurify with the recombinant Nef protein from either the BH10 or the LAV1 isolate. Purified recombinant BH10 Nef protein was used as an immunogen to elicit mouse monoclonal antibodies. A series of monoclonal antibodies were obtained which reacted with sequences at either the amino or carboxy terminus of Nef. In addition, a conformational epitope reacting with native BH10, but not LAV1, Nef was isolated.     

Alzheimer's associated variant ubiquitin causes inhibition of the 26S proteasome and chaperone expression

Intracellular protein inclusions in Alzheimer's disease and progressive supranuclear palsy contain UBB+1, a variant ubiquitin. UBB+1 is able block the 26S proteasome in cell lines. Proteasome inhibition by drug action has previously been shown to induce a heat-shock response and render protection against stress. We investigated UBB+1 by developing a stable, conditional expression model in SH-SY5Y human neuroblastoma cells. Induction of UBB+1 expression caused proteasome inhibition as was confirmed by reduced ability to process misfolded canavanyl proteins, accumulation of GFPu, a proteasome substrate, and reduced cleavage of a fluorogenic substrate. We show that expression of UBB+1 induces expression of heat-shock proteins. This priming of the chaperone system in these cells promotes a subsequent resistance to tert-butyl hydroperoxide-mediated oxidative stress. We conclude that although UBB+1-expressing cells have a compromised ubiquitin-proteasome system, they are protected against oxidative stress conditions.     

Establishment of Arthrobotrys flagrans as biocontrol agent against the root pathogenic nematode Xiphinema index

Plant-parasitic nematodes cause devastating agricultural damage worldwide. Only a few synthetic nematicides can be used and their application is limited in fields. Therefore, there is a need for sustainable and environment-friendly alternatives. Nematode-trapping fungi (NTF) are natural predators of nematodes. They capture and digest them with their hyphae and are starting to being used as bio-control agents. In this study, we applied the NTF Arthrobotrys flagrans (Duddingtonia flagrans) against the wine pathogenic nematode Xiphinema index. A. flagrans reduced the number of X. index juveniles in pot cultures of Ficus carica, an alternative host plant for X. index, significantly. Sodium-alginate pellets with A. flagrans spores were produced for vineyard soil inoculation under laboratory conditions. The NTF A. conoides, A. musiformis and A. superba were enriched from several soil samples, showing their natural presence. Trap formation is an energy-consuming process and depends upon various biotic and abiotic stimuli. Here, we show that bacteria of the genus Delftia, Bacillus, Pseudomonas, Enterobacter and Serratia induced trap formation in NTF like A. conoides and A. oligospora but not in A. flagrans in the absence of nematodes. The application of NTF along with such bacteria could be a combinatorial way of efficient biocontrol in nematode-infested soil.     

Agriculture under Climate Change in China: Mitigate the Risks by Grasping the Emerging Opportunities

ABSTRACT

There have been increasing concerns on risks and uncertainty posed by climate change to China's future crop production. The existing assessments using popular process-based and site-specific crop growing models highlight the significant extent of climate-induced yield reduction, and thus suggest a scary downward risk for China's future food production. Surprisingly, much less attention has been paid to exploring the potential gains that may also be brought by climate change. To address this imbalance, we develop an integrated agro-climatic and ecological assessment tool that is capable of detecting the shifts of multicropping opportunities under different climate change scenarios. The application of this tool to the context of China reveals significant extension of multicropping opportunities brought in by climate change. We argue for an active adaptation to such emerging opportunities through both market and policy incentives, because the aggregate gain of such adaptation is sufficient to outweigh the loss as revealed by the existing assessments.