Seroprevalence of Strongyloides stercoralis infection in a South Indian adult population

BackgroundThe prevalence of Strongyloides stercoralis infection is estimated to be 30–100 million worldwide, although this an underestimate. Most cases remain undiagnosed due to the asymptomatic nature of the infection. We wanted to estimate the seroprevalence of S. stercoralis infection in a South Indian adult population.MethodsTo this end, we performed community-based screening of 2351 individuals (aged 18–65) in Kanchipuram District of Tamil Nadu between 2013 and 2020. Serological testing for S. stercoralis was performed using the NIE ELISA.ResultsOur data shows a seroprevalence of 33% (768/2351) for S. stercoralis infection which had a higher prevalence among males 36% (386/1069) than among females 29.8% (382/1282). Adults aged ≥55 (aOR = 1.65, 95% CI: 1.25–2.18) showed higher adjusted odds of association compared with other age groups. Eosinophil levels (39%) (aOR = 1.43, 95% CI: 1.19–1.74) and hemoglobin levels (24%) (aOR = 1.25, 95% CI: 1.11–1.53) were significantly associated with S. stercoralis infection. In contrast, low BMI (aOR = 1.15, 95% CI: 0.82–1.61) or the presence of diabetes mellitus (OR = 1.18, 95% CI: 0.83–1.69) was not associated with S. stercoralis seropositivity.ConclusionsOur study provides evidence for a very high baseline prevalence of S. stercoralis infection in South Indian communities and this information could provide realistic and concrete planning of control measures.     

Recent advances in barley transformation

Barley, an important member of the cereals, has been successfully transformed through various methods such as particle bombardment, Agrobacterium tumefaciens, DNA uptake, and electroporation. Initially, the transformation in barley concentrated on developing protocols using marker genes such as gus, bar, and hpt. Immature embryos and callus derived from immature embryos were targeted for transformation. Subsequently, genes of agronomic and malting importance have been deployed in barley. Particle bombardment appears to be the preferred choice for barley transformation in the majority of the reports, although Agrobacterium-mediated transformation is being used more often. The current review focuses on the challenges encountered in barley transformation such as somaclonal variation, development of transformation systems for commercial cultivars, gene expression, stability and inheritance, and gene flow. Newer markers such as the green fluorescent protein (gfp), firefly luciferase, and phosphomannose isomerase were found to be useful in the selection of transgenic plants. Tissue-specific promoters such as those for B1-hordein and D-hordein genes, and spike-specific promoters, are increasingly used to drive gene expression. The review also describes recent research on gene-tagging through transformation, insertion of disease resistance, and abiotic stress resistance genes, transformation with genes for improved malting quality, nutrient content, feed quality, and the production of feed enzymes and pharmaceutical compounds.     

Characterization of replication origins flanking the 23S rRNA gene in tobacco chloroplast DNA

Using 5 end-labeled nascent strands of tobacco chloroplast DNA (ctDNA) as a probe, replication displacement loop (D-loop) regions were identified. The strongest hybridization was observed with restriction fragments containing the rRNA genes from the inverted repeat region. Two-dimensional gel analysis of various digests of tobacco ctDNA suggested that a replication origin is located near each end of the 7.1 kb BamHI fragment containing part of the rRNA operon. Analysis of in vitro replication products indicated that templates from either of the origin regions supported replication, while the vector alone or ctDNA clones from other regions of the genome did not support in vitro replication. Sequences from both sides of the BamHI site in the rRNA spacer region were required for optimal in vitro DNA replication activity. Primer extension was used for the first time to identify the start site of DNA synthesis for the D-loop in the rRNA spacer region. The major 5 end of the D-loop was localized to the base of a stem-loop structure which contains the rRNA spacer BamHI site. Primer extension products were insensitive to both alkali and RNase treatment, suggesting that RNA primers had already been removed from the 5 end of nascent DNA. Location of an origin in the rRNA spacer region of ctDNA from tobacco, pea and Oenothera suggests that ctDNA replication origins may be conserved in higher plants.     

Neurobehavioral Abnormalities in the HIV-1 Transgenic Rat Do Not Correspond to Neuronal Hypometabolism on 18F-FDG-PET

Motor and behavioral abnormalities are common presentations among individuals with HIV-1 associated neurocognitive disorders (HAND). We investigated whether longitudinal motor and behavioral performance in the HIV-1 transgenic rat (Tg), a commonly used neuro-HIV model, corresponded to in vivo neuronal death/dysfunction, by using rotarod and open field testing in parallel to [¹⁸F] 2-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET). We demonstrated that age-matched non-Tg wild type (WT) rats outperformed the HIV-1 Tg rats at most time points on rotarod testing. Habituation to rotarod occurred at 8 weeks of age (fifth weekly testing session) in the WT rats but it never occurred in the Tg rats, suggesting deficits in motor learning. Similarly, in open field testing, WT rats outperformed the Tg rats at most time points, suggesting defective exploratory/motor behavior and increased emotionality in the Tg rat. Despite the neurobehavioral abnormalities, there were no concomitant deficits in ¹⁸F-FDG uptake in Tg rats on PET compared to age-matched WT rats and no significant longitudinal loss of FDG uptake in either group. The negative PET findings were confirmed using ¹⁴C- Deoxy-D-glucose autoradiography in 32 week-old Tg and WT rats. We believe that the neuropathology in the HIV-1 Tg rat is more likely a consequence of neuronal dysfunction rather than overt neurodegeneration/neuronal cell death, similar to what is seen in HIV-positive patients in the post-ART era.