1.Fatty Acids of Densely Packed Embryos of Carcinus maenas Reveal Homogeneous Maternal Provisioning and No Within-Brood Variation at Hatching.
Rey F1, Moreira AS2, Ricardo F1, Coimbra MA2, Domingues MR2, Domingues P2, Rosa R3, Queiroga H1, Calado R4. Biol Bull. 2016 Apr;230(2):120-9.
Embryonic development of decapod crustaceans relies on yolk reserves supplied to offspring through maternal provisioning. Unequal partitioning of nutritional reserves during oogenesis, as well as fluctuating environmental conditions during incubation, can be sources of within-brood variability. Ultimately, this potential variability may promote the occurrence of newly hatched larvae with differing yolk reserves and an unequal ability to endure starvation and/or suboptimal feeding during their early pelagic life. The present study evaluated maternal provisioning by analyzing fatty acid (FA) profiles in newly extruded embryos of Carcinus maenas Also assessed were the dynamics of such provisioning during embryogenesis, such as embryo location within the regions of the brooding chamber (left external, left internal, right external, and right internal). The FA profiles surveyed revealed a uniform transfer of maternal reserves from the female to the entire mass of embryos, and homogeneous embryonic development within the brooding chamber.
2.Detection of amino acid substitutions in the GyrA protein of fluoroquinolone-resistant typhoidal Salmonella isolates using high-resolution mass spectrometry.
Hassing RJ1, Goessens WH2, Zeneyedpour L3, Sultan S4, van Kampen JJ4, Verbon A4, van Genderen PJ5, Hays JP4, Luider TM3, Dekker LJ3. Int J Antimicrob Agents. 2016 Mar 15. pii: S0924-8579(16)30019-X. doi: 10.1016/j.ijantimicag.2016.01.018. [Epub ahead of print]
Infections with typhoidal Salmonella isolates that are resistant to fluoroquinolone antibiotics have become very common in several Asian countries. In the majority of these cases, resistance to fluoroquinolone-based antibiotics is associated with genetic mutations in the quinolone resistance-determining region (QRDR) of the bacterial DNA gyrase gene gyrA. The objective of this study was to detect these amino acid substitutions by high-resolution mass spectrometry instead of sequencing of the gyrA gene. A liquid chromatography-mass spectrometry (LC-MS) methodology was developed and evaluated for the detection of amino acid substitutions in the GyrA protein of 23 typhoidal Salmonella isolates. These isolates included typhoidal Salmonella that possessed different antibiotic sensitivities to fluoroquinolone antibiotics. The LC-MS methodology correctly identified peptide sequences associated with phenotypic QRDR mutations of the GyrA protein in all 23 phenotypically diverse typhoidal Salmonella isolates tested.