Anatomical Factor for Formation of Peritonsillar Abscess in a Tertiary Care Centre.

Peritonsillar abscess is a polymicrobial infection with acute life threatening complications if not treated promptly. Primary objective is to find the anatomical factor for unilateral abscess formation and appropriate management protocols. Secondary objectives include the bacteriological study,antibiotic preference and comparison of crypt length of both tonsils post tonsillectomy to look for any significant association. A prospective study was carried out for one year in patients with peritonsillitis or peritonsillar abscess attending the Department of ENT in our hospital. Acute cases were treated by incision and drainage followed by IV antibiotics after taking pus or throat swab for culture and sensitivity. Patients further planned for interval tonsillectomy after 6 weeks followed by histopathological examination to compare the infected side and normal side. Crypt length measurements done to see any disparity which would have lead to the development of peritonsillar abscess unilaterally. In patients with peritonsillitis or peritonsillar abscess, histopathological examination of tonsils after interval tonsillectomy showed that risk of peritonsillitis or peritonsillar abscess were more on the tonsil with larger crypt length with more preponderance on left side and in males. This study concludes that deeper the crypt length,male sex, history of recurrent tonsillitis are main risk factors for development of peritonsillar abscess. Bacteriology showed Staphylococcus aureus against the most common Streptococcus Sp. Hence prompt use of antibiotics help in early recovery and reducing complications.

Human lysyl-tRNA synthetase phosphorylation promotes HIV-1 proviral DNA transcription.

Human lysyl-tRNA synthetase (LysRS) was previously shown to be re-localized from its normal cytoplasmic location in a multi-aminoacyl-tRNA synthetase complex (MSC) to the nucleus of HIV-1 infected cells. Nuclear localization depends on S207 phosphorylation but the nuclear function of pS207-LysRS in the HIV-1 lifecycle is unknown. Here, we show that HIV-1 replication was severely reduced in a S207A-LysRS knock-in cell line generated by CRISPR/Cas9; this effect was rescued by S207D-LysRS. LysRS phosphorylation up-regulated HIV-1 transcription, as did direct transfection of Ap4A, an upstream transcription factor 2 (USF2) activator that is synthesized by pS207-LysRS. Overexpressing an MSC-derived peptide known to stabilize LysRS MSC binding inhibited HIV-1 replication. Transcription of HIV-1 proviral DNA and other USF2 target genes was reduced in peptide-expressing cells. We propose that nuclear pS207-LysRS generates Ap4A, leading to activation of HIV-1 transcription. Our results suggest a new role for nuclear LysRS in facilitating HIV-1 replication and new avenues for antiviral therapy.

Crystallization and X-ray diffraction analysis of the HMG domain of the chondrogenesis master regulator Sox9 in complex with a ChIP-Seq-identified DNA element.

Sox9 is a fundamental sex-determining gene and the master regulator of chondrogenesis, and is involved in the development of various vital organs such as testes, kidney, heart and brain, and in skeletal development. Similar to other known Sox transcription factors, Sox9 recognizes and binds DNA with the consensus sequence C(T/A)TTG(T/A)(T/A) through the highly conserved HMG domain. Nonetheless, the molecular basis of the functional specificity of Sox9 in key developmental processes is still unclear. As an initial step towards a mechanistic understanding of Sox9 transcriptional regulation, the current work describes the details of the purification of the mouse Sox9 HMG domain (mSox9HMG), its crystallization in complex with a ChIP-Seq-identified FOXP2 promoter DNA element and the X-ray diffraction data analysis of this complex. The mSox9HMG-FOXP2 promoter DNA complex was crystallized by the hanging-drop vapour-diffusion method using 20% PEG 3350 in 200 mM sodium/potassium phosphate with 100 mM bis-tris propane at pH 8.5. The crystals diffracted to 2.7 Å resolution and the complex crystallized in the tetragonal space group P41212, with unit-cell parameters a = b = 99.49, c = 45.89 Å. Crystal-packing parameters revealed that asymmetric unit contained one mSox9HMG-FOXP2 promoter DNA complex with an estimated solvent content of 64%.

RSARF: prediction of residue solvent accessibility from protein sequence using random forest method.

Prediction of protein structure from its amino acid sequence is still a challenging problem. The complete physicochemical understanding of protein folding is essential for the accurate structure prediction. Knowledge of residue solvent accessibility gives useful insights into protein structure prediction and function prediction. In this work, we propose a random forest method, RSARF, to predict residue accessible surface area from protein sequence information. The training and testing was performed using 120 proteins containing 22006 residues. For each residue, buried and exposed state was computed using five thresholds (0%, 5%, 10%, 25%, and 50%). The prediction accuracy for 0%, 5%, 10%, 25%, and 50% thresholds are 72.9%, 78.25%, 78.12%, 77.57% and 72.07% respectively. Further, comparison of RSARF with other methods using a benchmark dataset containing 20 proteins shows that our approach is useful for prediction of residue solvent accessibility from protein sequence without using structural information. The RSARF program, datasets and supplementary data are available at http://caps.ncbs.res.in/download/pugal/RSARF/.