Rare subtypes of BK virus are viable and frequently detected in renal transplant recipients with BK virus-associated nephropathy

BK virus-associated nephropathy (BKVN) occurs in up to 5% of kidney transplants and is a significant cause of graft loss. Four major subtypes of BKV have been described, with the vast majority of individuals persistently infected with BKV Type I (> 80% of the population). Sequencing of BKV isolates subcloned from BKVN patients revealed a high percentage of variants in the urine (40%) in the VP1 subtyping region. In vitro analysis of several viral variants revealed that all variants recovered from the urine of BKVN patients produced infectious viral particles and were replication competent in cell culture while some of the variants induced cytopathic changes in infected cells when compared to the major BKV subtype, VP1 Type I. These results suggest that rare BKV VP1 variants are more frequently associated with disease and that some variants could be more cytopathic than others in renal transplant recipients

Meios de cultura, reguladores de crescimento e fontes de nitrogênio na regulação da calogênese do pau-brasil (Caesalpinia echinata Lam.) Culture media, growth regulators and nitrogen sources in callus formation regulation of Brazilwood (Caesalpinia echinata Lam.)

A regulação da calogênese é o primeiro passo para a embriogênese somática indireta in vitro. Nesse sentido, foram investigados os efeitos de diferentes meios de cultura, reguladores de crescimento e fontes nitrogenadas no desenvolvimento de calos em tecidos foliares de Caesalpinia echinata (pau-brasil). Explantes foliares foram cultivados em meios de cultura MS, B5, White e WPM. Testou-se, também, o efeito dos compostos nitrogenados (NH4NO3, KNO3 e glutamina) e a interação entre auxinas (2,4-D, AIA e AIB) e citocininas (BAP e KIN) na desdiferenciação celular indicado pela formação de calos. Os meios MS, B5 e White não foram significantemente diferentes e proporcionaram melhores resultados. Em meio MS contendo as fontes nitrogenadas 2,4 g L-1 NH4NO3 e 1,35 g L-1 glutamina + 4,11 g L-1 de KNO3 na presença de 1,0 mg L-1 2,4-D e 5,0 mg L-1 BAP ocorreu maior proliferação celular indicada pela massa fresca dos calos. As combinações dos reguladores 0,5 mg L-1 2,4-D + 5 mg L-1 BAP e 0,5 mg L-1 AIB + 5,0 mg L-1 BAP suplementado com 2,4 g L-1 NH4NO3 em meio MS estimularam o crescimento dos calos. De maneira geral, os calos apresentaram aspectos friáveis, não embriogênicos, com acúmulo de fenóis e presença de áreas meristemáticas (meristemóides).<br>The regulation of callus formation is the first step to indirect somatic embryogenesis in vitro. Therefore, we investigated hormonal and nutrient factors on development of callus in leaf tissues of Caesalpinia echinata (Brazilwood). Explants were cultivated in culture media MS, B5, WPM, and White. The effect of nitrogen sources (NH4NO3, KNO3 and glutamine) and the interaction between auxins (2,4-D, IAA and IBA) and cytokinins (BAP and KIN) were also evaluated. Media MS, B5 and White were not significantly different and provided better results. MS medium containing 2.4 g L-1 NH4NO3, 1.35 g L-1 glutamine, and 4.11 g L-1 of KNO3 in the presence of 1 mg.L-1 2,4-D and 5 mg.L-1 BAP increased cellular proliferation as determined by fresh weight of callus. The combination of plant growth regulators at 0.5 mg L-1 2,4-D + 5.0 mg L-1 BAP and 0.5 mg L-1 IBA + 5.0 mg L-1 BAP supplemented with 2.4 g L-1 NH4NO3 in MS medium stimulated growth of callus. In general, callus showed friable, non-embryogenic characteristics, with accumulation of phenolics and the presence of meristematic areas (meristems)

SARS-CoV-2 seroprevalence among the general population and healthcare workers in India, December 2020–January 2021

Background: Earlier serosurveys in India revealed seroprevalence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) of 0.73% in May–June 2020 and 7.1% in August–September 2020. A third serosurvey was conducted between December 2020 and January 2021 to estimate the seroprevalence of SARS-CoV-2 infection among the general population and healthcare workers (HCWs) in India. Methods: The third serosurvey was conducted in the same 70 districts as the first and second serosurveys. For each district, at least 400 individuals aged ≥10 years from the general population and 100 HCWs from subdistrict-level health facilities were enrolled. Serum samples from the general population were tested for the presence of immunoglobulin G (IgG) antibodies against the nucleocapsid (N) and spike (S1-RBD) proteins of SARS-CoV-2, whereas serum samples from HCWs were tested for anti-S1-RBD. Weighted seroprevalence adjusted for assay characteristics was estimated. Results: Of the 28,598 serum samples from the general population, 4585 (16%) had IgG antibodies against the N protein, 6647 (23.2%) had IgG antibodies against the S1-RBD protein, and 7436 (26%) had IgG antibodies against either the N protein or the S1-RBD protein. Weighted and assay-characteristic-adjusted seroprevalence against either of the antibodies was 24.1% [95% confidence interval (CI) 23.0–25.3%]. Among 7385 HCWs, the seroprevalence of anti-S1-RBD IgG antibodies was 25.6% (95% CI 23.5–27.8%). Conclusions: Nearly one in four individuals aged ≥10 years from the general population as well as HCWs in India had been exposed to SARS-CoV-2 by December 2020