Publications by authors named "R Ratnam"

Article Synopsis
  • Phenotypic drug susceptibility testing (DST) is the standard method for detecting resistance to linezolid (LZD) in Mycobacterium tuberculosis (MTB), but it takes a long time; nanopore sequencing might offer a quicker alternative.
  • The study involved analyzing drug-resistant MTB isolates by comparing phenotypic LZD resistance from liquid culture to targeted sequencing of specific genes (rrl and rplC) using nanopore technology.
  • Results showed a low agreement between sequencing and DST for LZD resistance, with only one mutation found in the rplC gene, indicating further research is needed to improve understanding of LZD resistance mechanisms and molecular diagnostics.
View Article and Find Full Text PDF

Background: Currently for diagnosing Mycobacterium tuberculosis and its drug resistance, two sputum samples are required. One of them is subjected to TrueNat™ and if positive the other sample is subjected to line probe assay (LPA). This study was done to evaluate whether TrueNat extracted DNA can be directly used for performing LPA in a diagnostic laboratory setting to decrease patient turn-around time.

View Article and Find Full Text PDF
Article Synopsis
  • * Out of 13,124 tested samples, 9,722 (74.1%) were rifampicin-sensitive, with 8.6% showing resistance to INH and 13.2% of those also resistant to FQ.
  • * Key mutations linked to INH resistance included katG S315T1 and inhA C15T, while the most notable FQ resistance mutation was gyrA D94G, with various additional mutation patterns also identified.
View Article and Find Full Text PDF
Are frog calls relatively difficult to locate by mammalian predators?

J Comp Physiol A Neuroethol Sens Neural Behav Physiol

January 2023

Frogs call in acoustically dense choruses to attract conspecific females. Their calls can potentially reveal their location to predators, many of which are mammals. However, frogs and mammals have very different acoustic receivers and mechanisms for determining sound source direction.

View Article and Find Full Text PDF

Negative correlations in the sequential evolution of interspike intervals (ISIs) are a signature of memory in neuronal spike-trains. They provide coding benefits including firing-rate stabilization, improved detectability of weak sensory signals, and enhanced transmission of information by improving signal-to-noise ratio. Primary electrosensory afferent spike-trains in weakly electric fish fall into two categories based on the pattern of ISI correlations: non-bursting units have negative correlations which remain negative but decay to zero with increasing lags (Type I ISI correlations), and bursting units have oscillatory (alternating sign) correlation which damp to zero with increasing lags (Type II ISI correlations).

View Article and Find Full Text PDF