Social odours covary with bacterial community in the anal secretions of wild meerkats.

The fermentation hypothesis for animal signalling posits that bacteria dwelling in an animal's scent glands metabolize the glands' primary products into odorous compounds used by the host to communicate with conspecifics. There is, however, little evidence of the predicted covariation between an animal's olfactory cues and its glandular bacterial communities. Using gas chromatography-mass spectrometry, we first identified the volatile compounds present in 'pure' versus 'mixed' anal-gland secretions ('paste') of adult meerkats (Suricata suricatta) living in the wild.

The "secret" in secretions: methodological considerations in deciphering primate olfactory communication.

Olfactory communication in primates is gaining recognition; however, studies on the production and perception of primate scent signals are still scant. In general, there are five tasks to be accomplished when deciphering the chemical signals contained in excretions and secretions: (1) obtaining the appropriate samples; (2) extracting the target organic compounds from the biological matrix; (3) separating the extracted compounds from one another (by gas chromatography, GC or liquid chromatography, LC); (4) identifying the compounds (by mass spectrometry, MS and associated procedures); and (5) revealing biologically meaningful patterns in the data. Ultimately, because some of the compounds identified in odorants may not be relevant, associated steps in understanding signal function involve verifying the perception or biological activity of putative semiochemicals via (6) behavioral bioassays or (7) receptor response studies.

Burkholdines from Burkholderia ambifaria: antifungal agents and possible virulence factors.

Burkholdines are cyclic lipopeptides with unusual antifungal potency, making them promising leads as a new class of antifungal agents. However, a recent report using knockout mutagenesis indicates that these and related compounds, such as occidiofungins, xylocandins, and cepacidines, may also be synonymous with the long-known hemolytic virulence factors found in diverse Burkholderia isolates. Because of their possible roles in causing Burkholderia infections or curing fungal infections, it is important to fully define their structures and biological activities using pure compounds.

Eulemur, me lemur: the evolution of scent-signal complexity in a primate clade.

Signal complexity has been linked to social complexity in vocal, but not chemical, communication. To address this gap, we examined the chemical complexity of male and female glandular secretions in eight species of Eulemur. In this diverse clade of macrosmatic primates, species differ by social or mating system and dominance structure.

Burkholdines 1097 and 1229, potent antifungal peptides from Burkholderia ambifaria 2.2N.

Potent antifungal cyclic lipopeptides, burkholdines (Bk), were isolated from a culture of Burkholderia ambifaria 2.2N. Bk-1229 (1) and Bk-1097 (2) are octapeptides comprised of nonproteinogenic amino acids, including beta-hydroxytyrosine, beta-hydroxyasparagine, and a new fatty acyl amino acid.

FAB mass spectrometry of Au25(SR)18 nanoparticles.

The molecular ion of the nanoparticle Au 25(SCH 2CH 2Ph) 18 (A 25(SR) 18) is observed at 7394 Da in fast atom bombardment (FAB, Xe atoms) ionization mass spectrometry using a 3-nitrobenzyl alcohol matrix. A distinctive pattern of positive fragment ions is evident in the mass interval 5225-7394 Da, where peaks are seen for successive mass losses equivalent to R 2S entities. Because the Au 25(SCH 2CH 2Ph) 18 nanoparticle structure is crystallographically known to consist of a centered Au 13 icosahedral core surrounded by six Au 2(SR) 3 semirings, the R 2S loses are proposed to represent serial rearrangements and decompositions of the semiring structures.

Nanoparticle MALDI-TOF mass spectrometry without fragmentation: Au25(SCH2CH2Ph)18 and mixed monolayer Au25(SCH2CH2Ph)(18-x)(L)(x).

Intact molecular ions of the organothiolate-protected nanoparticle Au25(SCH2CH2Ph)18, including their isotopic resolution, can be observed at 7391 Da as 1- and 1+ ions in negative and positive mode, respectively, by MALDI-TOF mass spectrometry when using a tactic of threshold laser pulse intensities and trans-2-[3-(4-tert-butylphenyl)-2-methyl-2-propenylidene]malononitrile (DCTB) as matrix. Previous MALDI-TOF studies of Au nanoparticles using other matrices have encountered extensive fragmentation of nanoparticle as well as thiolate ligands. Absence of fragmentation enables precise determination of the distribution of mixed monolayer compositions on nanoparticles prepared by ligand exchange reactions and by synthesis using thiol mixtures.

Chemical composition of scent marks in the ringtailed lemur (Lemur catta): glandular differences, seasonal variation, and individual signatures.

The apocrine and sebaceous scent glands of ringtailed lemurs (Lemur catta) appear to serve different social functions. In behavioral experiments, lemurs modulate their responses to scent marks based on the type of odorant, their own physiological state, the signaler's physiological state, and prior social experience. To examine variation in odorant chemistry relative to olfactory behavior, we used gas chromatography and mass spectrometry to analyze over 86 samples of glandular secretion collected over 2 years from 15 adult lemurs.

Increased rate of glutathione synthesis from cystine in drug-resistant MCF-7 cells.

The rate of glutathione synthesis was determined in drug-sensitive and -resistant MCF-7 cells by monitoring the rate of label uptake from [3,3'-13C(2)]-cystine using NMR spectroscopy and mass spectrometry. Compared with the wild-type human mammary adenocarcinoma cell line (MCF-7wt), the isotope incorporation rate was increased 1.6-, 2.