Arkady P. Sinitsyn

Introduction The complexity of the microbial populations in sedimentary environments is universally acknowledged, with major challenges to their study arising from the unculturable nature of the major proportion of such populations [1]. This places considerable emphasis on the use of indirect approaches (e.g. field- or laboratory-based CO2 flux measurements) and/or culture-independent methods, to investigate the nature and functional ecology of such microbes.

2. Materials and Methods 2.1. Strains of Microorganisms The recipient strain of the mycelial fungus P. verruculosum B1-537 (F-3972D, All-Russian collection of microorganisms, Puschino, Russia), which is defective in the niaD gene encoding intact nitrate reductase, was used in this study. A strain of mycelial fungus P.