The mcyB, aerB, and apnC genes occurred in

99%, 99%, and 97% of the samples, respectively, and on average comprised 60 ± 3%, 22 ± 2%, and 54 ± 4% of the total population, respectively. Although the populations differed widely in abundance (10−3–103 mm3 L−1) no dependence of the proportion of the mcyB, aerB, and apnC genes on the density of the total population was found. In contrast populations differed significantly in their average mcyB, aerB, and apnC gene proportions, with no change between prebloom and bloom conditions. These results emphasize stable population-specific differences in mcyB, aerB, and apnC proportions that are independent from seasonal influences. “
“Antimicrobial peptides (AMPs) are present in virtually all organisms selleckchem and are an ancient and critical component of innate immunity. In mammals, AMPs are present in phagocytic cells, on body surfaces such as skin and mucosa, and in secretions and selleck screening library body fluids such as sweat, saliva, urine,

and breast milk, consistent with their role as part of the first line of defense against a wide range of pathogenic microorganisms including bacteria, viruses, and fungi. AMPs are microbicidal and have also been shown to act as immunomodulators with chemoattractant and signaling activities. During the co-evolution of hosts and bacterial pathogens, bacteria have developed the ability to sense and initiate an adaptive response to AMPs to resist their bactericidal activity. Here, we review the various mechanisms used by Gram-negative bacteria to sense and resist AMP-mediated killing. These mechanisms play an important role in bacterial resistance to host-derived AMPs that are encountered during the course of infection. Bacterial resistance to AMPs should also be taken into consideration in the

development and use of AMPs as anti-infective agents, for which there is currently a great deal of academic and commercial interest. Mammalian antimicrobial peptides (AMPs) are diverse Terminal deoxynucleotidyl transferase in sequence and are classified into families on the basis of their structures and functions (Hancock & Sahl, 2006). Two major families of AMPs in mammals are the defensins and the cathelicidins (Table 1). Defensins are cysteine-rich cationic peptides that form β-sheet structures and contain disulfide bonds. The position of the disulfide bonds is used to further classify defensins into subfamilies (α- and β-defensins in mice and humans). Of note, murine α-defensins are often designated as cryptdins (Eisenhauer et al., 1992). Cathelicidins are also positively charged, but do not have disulfide bonds. Rather, they form amphipathic α-helices with a positively charged face. There is only one cathelicidin member present in humans and mice, named LL-37 and murine cathelicidin-related antimicrobial peptide (mCRAMP), respectively.