On the Distributed Construction of Stable Networks in Polylogarithmic Parallel Time

We study the class of networks, which can be created in polylogarithmic parallel time by network constructors: groups of anonymous agents that interact randomly under a uniform random scheduler with the ability to form connections between each other. Starting from an empty network, the goal is to construct a stable network that belongs to a given family. We prove that the class of trees where each node has any k≥2 children can be constructed in O(logn) parallel time with high probability. We show that constructing networks that are k-regular is Ω(n) time, but a minimal relaxation to (l,k)-regular networks, where l=k−1, can be constructed in polylogarithmic parallel time for any fixed k, where k>2. We further demonstrate that when the finite-state assumption is relaxed and k is allowed to grow with n, then k=loglogn acts as a threshold above which network construction is, again, polynomial time. We use this to provide a partial characterisation of the class of polylogarithmic time network constructors.

Isolation and partial characterisation of secondary metabolites from fish-borne bacterium, Pseudomonas aeruginosa

Partial characterisation of secondary metabolites of a potent antagonistic bacterium Pseudomonas aeruginosa FARP72 (NCBI GenBank Accession No. KC570343) isolated from the skin mucus of catfish Clarias batrachus was attempted in this study. The antagonistic activity of P. aeruginosa was confirmed by cross and parallel streaking methods against three bacterial fish pathogens (Aeromonas caviae, Edwardsiella tarda and β-haemolytic Streptococcus sp.) and seven human bacterial pathogens viz., Klebsiella pneumoniae, Enterohaemorrhagic Escherichia coli, Escherichia coli, Staphylococcus aureus ATCC 12598, Salmonella Typhi (serovar of Salmonella enterica sub sp. enterica), Vibrio cholerae and Bacillus pumilus. The antibacterial activities of the crude ethyl acetate extract of the whole cell of P. aeruginosa and the spent medium were also tested against the pathogens by well and disc diffusion assays. The ethyl acetate extract of P. aeruginosa cells was subjected to column chromatography packed with silica gel (60-120 mm mesh size) using petroleum ether and ethyl acetate in different concentrations as the mobile phase. The compounds of the bioactive fractions were semi purified and partially characterised using thin layer chromatography and mass spectroscopy. The secondary metabolites were identified to be pyrols, quinoline and phenazine compounds. The results suggested that the bioactive fractions of whole P. aeruginosa cells have potential antibacterial activity, which can be used as an alternative to conventional antibiotics to control fish and human pathogens.