Marine mammal conservation: over the horizon

Marine mammals can play important ecological roles in aquatic ecosystems, and their presence can be key to community structure and function. Consequently, marine mammals are often considered indicators of ecosystem health and flagship species. Yet, historical population declines caused by exploitation, and additional current threats, such as climate change, fisheries bycatch, pollution and maritime development, continue to impact many marine mammal species, and at least 25% are classified as threatened (Critically Endangered, Endangered or Vulnerable) on the IUCN Red List. Conversely, some species have experienced population increases/recoveries in recent decades, reflecting management interventions, and are heralded as conservation successes. To continue these successes and reverse the downward trajectories of at-risk species, it is necessary to evaluate the threats faced by marine mammals and the conservation mechanisms available to address them. Additionally, there is a need to identify evidence-based priorities of both research and conservation needs across a range of settings and taxa. To that effect we: (1) outline the key threats to marine mammals and their impacts, identify the associated knowledge gaps and recommend actions needed; (2) discuss the merits and downfalls of established and emerging conservation mechanisms; (3) outline the application of research and monitoring techniques; and (4) highlight particular taxa/populations that are in urgent need of focus.

Nesprin-2-dependent ERK1/2 compartmentalisation regulates the DNA damage response in vascular smooth muscle cell ageing

Prelamin A accumulation and persistent DNA damage response (DDR) are hallmarks of vascular smooth muscle cell (VSMC) ageing and dysfunction. Although prelamin A is proposed to interfere with DNA repair, our understanding of the crosstalk between prelamin A and the repair process remains limited. The extracellular signal-regulated kinases 1 and 2 (ERK1/2) have emerged as key players in the DDR and are known to enhance ataxia telangiectasia-mutated protein (ATM) activity at DNA lesions, and in this study, we identified a novel relationship between prelamin A accumulation and ERK1/2 nuclear compartmentalisation during VSMC ageing. We show both prelamin A accumulation and increased DNA damage occur concomitantly, before VSMC replicative senescence, and induce the localisation of ERK1/2 to promyelocytic leukaemia protein nuclear bodies (PML NBs) at the sites of DNA damage via nesprin-2 and lamin A interactions. Importantly, VSMCs treated with DNA damaging agents also displayed prelamin A accumulation and ERK compartmentalisation at PML NBs, suggesting that prelamin A and nesprin-2 are novel components of the DDR. In support of this, disruption of ERK compartmentalisation at PML NBs, by either depletion of nesprin-2 or lamins A/C, resulted in the loss of ATM from DNA lesions. However, ATM signalling and DNA repair remained intact after lamins A/C depletion, whereas nesprin-2 disruption ablated downstream Chk2 activation and induced genomic instability. We conclude that lamins A/C and PML act as scaffolds to organise DNA-repair foci and compartmentalise nesprin-2/ERK signalling. However, nesprin-2/ERK signalling fidelity, but not their compartmentalisation at PML NBs, is essential for efficient DDR in VSMCs.

Quantitative analysis of alprazolam and triazolam in hemolysed whole blood and liver digest by GC/MS/NICI with deuterated internal standards

This report describes sensitive and specific methods for the quantitation of alprazolam and triazolam in hemolysed whole blood and liver tissue. Samples of blood and enzyme-digested liver are extracted without pH adjustment with n-butyl chloride, after addition of deuterated internal standards and urea. The evaporated extracts are reconstituted in acetonitrile for analysis by gas chromatography/mass spectrometry/negative ion chemical ionization (GC/MS/NICI). Fatty extracts may be cleaned up by partitioning between pentane and acetonitrile. Two ion pairs are monitored for each drug. Within-day coefficients of variation in the range 10-50 micrograms/L for blood are approximately 5%. Between-day coefficients of variation are less than 10%. The limit of quantitation (based on analysis of 0.2-mL blood samples) is 0.5 microgram/L for triazolam and 4 micrograms/L for alprazolam.

Number- and Weight-Average Molecular Weights for Some Proanthocyanidin Polymers (Condensed Tannins)

The number-average molecular weights (Mn) and weight-average molecular weights (Mw) for proanthocyanidin polymers (condensed tannins) have been measured by vapour pressure osmometry and low-angle laser light-scattering measurements in methanol. These confirm earlier findings (based on gel permeation chromatography of the peracetate derivatives of these polymers) that they are polydisperse. The results also indicate that the incidence of branching in the polymer chains increases as the average chain length increases.

The protonation reactions of catechin, epicatechin and related compounds

The protonation reactions for catechin and epicatechin have been studied at 25�C, I 0.10M (KCl). Equilibrium constants Kn for the protonation steps of the anions L4- have been determined from potentiometric and/or spectrophotometric measurements. The logKn values for the epimers differed significantly only for logKl and logK4 (values for catechin 13.26 � 0.05, 11.26 � 0.06, 9.41 � 0.02, 8.64 � 0.01, and epicatechin 13.40 � 0.05, ll.23 � 0.06, 9.49 � 0.02, 8.72 � .01, n = 1-4 respectively). These differences are ascribed to specific solvation effects or ion associations between K+ and the ligand anions. Epimerization was studied by h.p.l.c., and was found to be minimal over the experimental time scale at pH c. 13.5. The ring on which each stepwise protonation occurs was elucidated by reference to log Kn values measured for the model compounds catechol, 4-methylbenzene-1,2-diol, protocatechuic acid and 3',4'-di-O-methylcatechin. The protonation sequence is B ring, A ring, B ring and A ring. In contrast to earlier results, it has been established that the epimerization of catechin or epicatechin at C2, and the formation of catechinic acid in basic solution, may proceed through a radical rather than ionic mechanism.

N.M.R. determination of the sites of coordination of some paramagnetic metal ions with Adenosine-5'-monophosphate

The 1H and 31P magnetic resonance spectra of adenosine-5'-monophosphate (AMP) have been recorded as a function of pD in the presence and absence of low molar-ratios of the paramagnetic metal ions Mn2+, Ni2+, Co2+ Cr3+, CU2+, Fe2+, and Fe3+. All of these cations form chelate complexes involving the phosphate moiety and the adenine ring of AMP, but different binding sites on the adenine ring appear to be utilized.

Synthesis and infrared spectra of some transition metal complexes of α-amino acid esters

A variety of transition metal complexes of a-amino acid esters have been synthesized, and characterized by analysis, conductivity measurements, and infrared spectra. The complexes can be broadly divided into two groups: (a) complexes in which only a metal-nitrogen bond occurs with the α-amino group of the ester, and (b) complexes in which chelate ring formation occurs via secondary donor groups on the ligand. These latter complexes are found with methyl L-histidinate, methyl γ-glutamate, and methyl L-cysteinate. With the exception of a methyl tryptophanate complex, the infrared spectra show that there is no interaction between the carbonyl group of the ester and the metal ion. The visible spectra of aqueous solutions of the esters and copper(II) at a ligand/metal ratio of 5 : 1 have maxima in the 600-650 mμ range at pH 7 consistent with copper-nitrogen bonding only.

The basic hydrolysis of amino acid esters

The kinetics of alkaline hydrolyses of nine amino acid esters by the process H,2NCHRCO2R'+OH- + H2NCHRCO2-+R'OH have been studied at 25� and an ionic strength of 0.1M in water over a range of pH. The acid ionization constants of the various amino acid esters have been determined, and these are roughly 2 pK units lower than those of the corresponding amino acids. The kinetic measurements are interpretable on the basis of electrostatic and steric effects.