JC polyomavirus infection in candidates for kidney transplantation living in the Brazilian Amazon Region

This study evaluated the relative occurrences of BK virus (BKV) and JC virus (JCV) infections in patients with chronic kidney disease (CKD). Urine samples were analysed from CKD patients and from 99 patients without CKD as a control. A total of 100 urine samples were analysed from the experimental (CKD patients) group and 99 from the control group. Following DNA extraction, polymerase chain reaction (PCR) was used to amplify a 173 bp region of the gene encoding the T antigen of the BKV and JCV. JCV and BKV infections were differentiated based on the enzymatic digestion of the amplified products using BamHI endonuclease. The results indicated that none of the patients in either group was infected with the BKV, whereas 11.1% (11/99) of the control group subjects and 4% (4/100) of the kidney patients were infected with the JCV. High levels of urea in the excreted urine, low urinary cellularity, reduced bladder washout and a delay in analysing the samples may have contributed to the low prevalence of infection. The results indicate that there is a need to increase the sensitivity of assays used to detect viruses in patients with CDK, especially given that polyomavirus infections, especially BKV, can lead to a loss of kidney function following transplantation.     

Biogeography of mutualistic fungi cultivated by leafcutter ants

Leafcutter ants propagate co‐evolving fungi for food. The nearly 50 species of leafcutter ants (Atta, Acromyrmex) range from Argentina to the United States, with the greatest species diversity in southern South America. We elucidate the biogeography of fungi cultivated by leafcutter ants using DNA sequence and microsatellite‐marker analyses of 474 cultivars collected across the leafcutter range. Fungal cultivars belong to two clades (Clade‐A and Clade‐B). The dominant and widespread Clade‐A cultivars form three genotype clusters, with their relative prevalence corresponding to southern South America, northern South America, Central and North America. Admixture between Clade‐A populations supports genetic exchange within a single species, Leucocoprinus gongylophorus. Some leafcutter species that cut grass as fungicultural substrate are specialized to cultivate Clade‐B fungi, whereas leafcutters preferring dicot plants appear specialized on Clade‐A fungi. Cultivar sharing between sympatric leafcutter species occurs frequently such that cultivars of Atta are not distinct from those of Acromyrmex. Leafcutters specialized on Clade‐B fungi occur only in South America. Diversity of Clade‐A fungi is greatest in South America, but minimal in Central and North America. Maximum cultivar diversity in South America is predicted by the Kusnezov–Fowler hypothesis that leafcutter ants originated in subtropical South America and only dicot‐specialized leafcutter ants migrated out of South America, but the cultivar diversity becomes also compatible with a recently proposed hypothesis of a Central American origin by postulating that leafcutter ants acquired novel cultivars many times from other nonleafcutter fungus‐growing ants during their migrations from Central America across South America. We evaluate these biogeographic hypotheses in the light of estimated dates for the origins of leafcutter ants and their cultivars.     

SARS-CoV-2 seroprevalence in health care workers from 10 hospitals in Quebec,Canada: a cross-sectional study

Background:The COVID-19 pandemic has disproportionately affected health care workers. We sought to estimate SARS-CoV-2 seroprevalence among hospital health care workers in Quebec, Canada, after the first wave of the pandemic and to explore factors associated with SARS-CoV-2 seropositivity.Methods:Between July 6 and Sept. 24, 2020, we enrolled health care workers from 10 hospitals, including 8 from a region with a high incidence of COVID-19 (the Montréal area) and 2 from low-incidence regions of Quebec. Eligible health care workers were physicians, nurses, orderlies and cleaning staff working in 4 types of care units (emergency department, intensive care unit, COVID-19 inpatient unit and non-COVID-19 inpatient unit). Participants completed a questionnaire and underwent SARS-CoV-2 serology testing. We identified factors independently associated with higher seroprevalence.Results:Among 2056 enrolled health care workers, 241 (11.7%) had positive SARS-CoV-2 serology. Of these, 171 (71.0%) had been previously diagnosed with COVID-19. Seroprevalence varied among hospitals, from 2.4% to 3.7% in low-incidence regions to 17.9% to 32.0% in hospitals with outbreaks involving 5 or more health care workers. Higher seroprevalence was associated with working in a hospital where outbreaks occurred (adjusted prevalence ratio 4.16, 95% confidence interval [CI] 2.63–6.57), being a nurse or nursing assistant (adjusted prevalence ratio 1.34, 95% CI 1.03–1.74) or an orderly (adjusted prevalence ratio 1.49, 95% CI 1.12–1.97), and Black or Hispanic ethnicity (adjusted prevalence ratio 1.41, 95% CI 1.13–1.76). Lower seroprevalence was associated with working in the intensive care unit (adjusted prevalence ratio 0.47, 95% CI 0.30–0.71) or the emergency department (adjusted prevalence ratio 0.61, 95% CI 0.39–0.98).Interpretation:Health care workers in Quebec hospitals were at high risk of SARS-CoV-2 infection, particularly in outbreak settings. More work is needed to better understand SARS-CoV-2 transmission dynamics in health care settings.

The COVID-19 pandemic has disproportionately affected health care workers. In France, Spain, Italy, Germany and the United States, at least 10% of cases reported in spring 2020 were in health care workers.¹ In Quebec, 25% (14 177 of 56 565) of all cases declared during the first wave of the pandemic, from March to July 2020, were in health care workers,² about one-third of whom were working in acute care hospitals.¹ The Montréal area was the most affected region in Quebec and Canada during the first wave, reaching a COVID-19 incidence rate of 1336 per 100 000 population.²The number of COVID-19 cases reported among health care workers underestimated the number of those infected with SARS-CoV-2 during that period, given limited testing leading to undiagnosed asymptomatic or paucisymptomatic infections.³ Seroprevalence studies are an important tool to determine the proportion of people infected with SARS-CoV-2, both in the general population and among health care workers.⁴ After the first wave in Quebec, SARS-CoV-2 seroprevalence in adults aged 18–69 years was found to be low (3.1% in Montréal and 1.3% in less affected regions), but this proportion could be much higher among health care workers who had to work despite the general shutdown of social and economic activities, especially if they were exposed to major outbreaks.⁵Only 2 other Canadian studies provide SARS-CoV-2 seroprevalence estimates among health care workers, and both studies were from a single centre.^6,7 Outside Canada, most seroprevalence studies among health care workers include a single site and do not provide a representative estimate for a defined region.⁸ Several studies have reported a higher seroprevalence among health care workers from units treating patients with COVID-19 (COVID-19 units) compared with other units (non–COVID-19 units), emergency departments or intensive care units.^9,10 Other studies have not identified such associations.^11,12 In this study, we aimed to assess the seroprevalence of SARS-CoV-2 antibody among hospital health care workers from a variety of settings after the first pandemic wave in Quebec, and to explore factors associated with SARS-CoV-2 seropositivity.     

Flavonol glycosides of Carya pecan

The flavonol glycosides characterized from the branches of Carya pecan include three new compounds, azaleatin 3-glucoside azaleatin 3-diglycoside and caryatin 3′- (or 4′-) rhamnoglucoside. together with azaleatin 3-rhamnoside. In the leaf tissue, quercetin 3-glucoside, quercetin 3-galactoside, quercetin 3-rhamnoside, quercetin 3-arabinoside and a small amount of kaempferol 3-monomethyl ether were identified.     

Some ecological aspects of Lake Qarun,Fayoum, Egypt. Part II. Production of plankton and benthic organisms

Distribution and abundance of phyto-, zooplankton and benthic organisms in Lake Qarun were investigated during the period from January 1974 to December 1977.Average number of phytoplankton cells was 152,300 cells/L and its biomass was 0.365 g/C/m³; average number of zooplankton was 31.44 × 10³/m³ and its biomass was 194.19 mg/m³. The average number of benthic fauna was 19889/m² and its biomass was 400.22 g/m² (dry wt.). Therefore, Lake Qarun may be considered as a highly eutrophic body of water.Freshwater planktonic species, that used to inhabit the lake, such as Diaptomus salinus and the cladoceran Moina salinarum, disappeared completely when the salinity of the lake water reached 30–34 However, some Rotatoria were able to withstand the high salinity. The new composition of the zooplankton community shows that the marine zooplankton species include not only Acartia latisetosa and Cirripedia nauplii, but also other species such as Polychaeta, Obelia medusae, etc.The benthos of Lake Qarun is characterised by an intensive growth of few species. The major part (i.e. 93.54% by weight) of bottom fauna in the lake is Mollusca, mainly Cerastoderma glaucum (69·84% by weight).     

Hepatic methionine adenosyltransferase deficiency in a 31-year-old man.

A 31-year-old man with hepatic methionine adenosyltransferase (MAT) deficiency was evaluated for an odd odor to his breath. He had no other symptoms. Plasma methionine was 716 microM (normal, 15-40 microM), and plasma methionine-oxidation products were 460 microM (normal, 0). Hepatic MAT activity was 28% of normal. Unlike the control human enzyme, the patient's residual MAT activity was not stimulated by 10% dimethylsulfoxide and the velocity was not increased by high substrate concentration; at 1.0 mM methionine, the patient's MAT activity was only 7% of normal. These biochemical findings are consistent with a deficiency of the high-Km isoenzyme of MAT. Despite this enzyme deficiency, liver histology and clinical tests of hepatic and other organ function were normal. The patient, who is 25 years older than the oldest reported individual with MAT deficiency, provides evidence that partial MAT deficiency is a benign disorder and that chronic hypermethioninemia (less than 1 mM) is not by itself detrimental to health.