Franconibacter pulveris strain DJ34, isolated from Duliajan oil fields, Assam, was characterized in terms of its taxonomic, metabolic and genomic properties. The bacterium showed utilization of diverse petroleum hydrocarbons and electron acceptors, metal resistance, and biosurfactant production. The genome (4,856,096bp) of this strain contained different genes related to the degradation of various petroleum hydrocarbons, metal transport and resistance, dissimilatory nitrate, nitrite and sulfite reduction, chemotaxy, biosurfactant synthesis, etc. Genomic comparison with other Franconibacter spp. revealed higher abundance of genes for cell motility, lipid transport and metabolism, transcription and translation in DJ34 genome. Detailed COG analysis provides deeper insights into the genomic potential of this organism for degradation and survival in oil-contaminated complex habitat. This is the first report on ecophysiology and genomic inventory of Franconibacter sp. inhabiting crude oil rich environment, which might be useful for designing the strategy for bioremediation of oil contaminated environment.

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In sickle cell anemia patients, red blood cells (RBCs) are known to become sickle shaped and stiff under hypoxic conditions as a consequence of hemoglobin polymerization. While RBC shape can discriminate sickle blood from healthy, it has not been used until now as a sole biophysical marker to differentiate between homozygous (disease) and heterozygous (trait) sickle blood samples. Here, we establish a technique based on the differential response of disease and trait RBCs to chemically-induced hypoxia to distinguish between these samples for the first time. By comparing the RBC shape distributions in blood treated with high and low concentrations of the hypoxia-inducing agent, we correctly identify 35 unknown blood samples as healthy, sickle cell disease or trait. Finally, we demonstrate our image-based classification technique with a portable smartphone microscope and a disposable microfluidic chip as a prospective point-of-care device enabling fast and confirmed diagnosis of sickle cell anemia.

Step emulsification (SE), which generates droplets by a sharp change in confinement, has emerged as a potential alternative to flow-focusing technology. Water/dispersed phase is continuously pumped through a shallow inlet channel into a deep chamber pre-filled with the oil/continuous phase. The need for one or more pumps to maintain a continuous flow for droplet generation, and the consequent use of high sample volumes, limit this technique to research labs. Here, we report a pump-free SE technique for rapid and high-throughput generation of monodisperse hydrogel (agarose) beads using <40 μl sample volume. Instead of using syringe pumps, we sequentially pipetted oil and liquid agarose into a microfluidic SE device to generate between 20000 and 80000 agarose beads in ~ 2 min. We also demonstrated the encapsulation of loop-mediated isothermal amplification mixture inside these beads at the time of their formation. Finally, using these beads as reaction chambers, we amplified nucleic acids from P. falciparum and SARS-CoV-2 inside them. The pump-free operation, tiny sample volume, and high-throughput generation of droplets by SE make our technique suitable for point-of-care diagnostics.