Described herein is a Mycobacterium mutant, comprising at least one mutation in at least one gene sequence encoding global gene regulators (GGRs) selected from the group consisting of sigH, sigL, sigE, ECF-1, and mixtures thereof, wherein the GGR gene is at least partially inactivated. Described herein also is a vaccine based on the mutant and a method of differentiating between subjects that have been infected with Mycobacterium and subjects that have not been infected with Mycobacterium or have been vaccinated with a Mycobacterium vaccine.

Described herein is a mycobacterium mutant, comprising at least one mutation in at least one gene sequence encoding global gene regulators (GGRs) selected from the group consisting of sigH, sigL, sigE, ECF-1, and mixtures thereof, wherein the GGR gene is at least partially inactivated. Described herein also is a vaccine based on the mutant and a method of differentiating between subjects that have been infected with mycobacterium and subjects that have not been infected with mycobacterium or have been vaccinated with a mycobacterium vaccine.

A device for selectively capturing mycobacteria comprises a substrate and a capture polymer layer of poly-diallyldimethyl ammonium chloride, wherein the capture polymer layer is covalently linked onto the substrate via a UV-initiated polymerization reaction of a solution comprising diallyldimethyl ammonium chloride and a photoinitiator in water purged of dissolved oxygen, and wherein the UV exposure time is 30 seconds to 4 minutes at a power density of about 20 to about 25 mW/cm.sup.2. A kit can comprise the device. A microfluidic chip comprises at least a portion of at least one channel sidewall coated with a capture polymer layer of poly-diallyldimethyl ammonium chloride. A method for manufacturing the device includes plasma treating a substrate, providing a solution comprising diallyldimethyl ammonium chloride and a photoinitiator in water purged of dissolved oxygen, and coating the plasma-treated substrate via a UV-initiated polymerization reaction.

The present invention provides a Mnep monomer variant including an amino acid sequence with any one or more amino acid mutations at positions 92-104 of SEQ ID NO: 1, a porin or construct including at least one Mnep monomer variant, and a use thereof. The present invention also provides a method for characterizing a target polynucleotide.