Visual methods for the nanomolar detection of electrophilic reagents

A series of highly colored nitrophenolates and nitrothiophenolates has been tested as spray reagents for the detection of electrophilic species of the types commonly used in peptide and protein chemistry. Sensitive TLC detection of agents for alkylation, acylation, sulfonylation and phosphorylation was demonstrated. In addition, the thiophenolate sprays were sensitive for oxidizing agents in nanomolar quantities. Selective TLC detection of acylating and phosphorylating agents was accomplished by subsequent alkali treatment resulting in the restoration of color.     

Cardiac mechanical efficiency is preserved in primary cardiac hypertrophy despite impaired mechanical function

Increased heart size is a major risk factor for heart failure and premature mortality. Although abnormal heart growth subsequent to hypertension often accompanies disturbances in mechano-energetics and cardiac efficiency, it remains uncertain whether hypertrophy is their primary driver. In this study, we aimed to investigate the direct association between cardiac hypertrophy and cardiac mechano-energetics using isolated left-ventricular trabeculae from a rat model of primary cardiac hypertrophy and its control. We evaluated energy expenditure (heat output) and mechanical performance (force length work production) simultaneously at a range of preloads and afterloads in a microcalorimeter, we determined energy expenditure related to cross-bridge cycling and Ca²⁺ cycling (activation heat), and we quantified energy efficiency. Rats with cardiac hypertrophy exhibited increased cardiomyocyte length and width. Their trabeculae showed mechanical impairment, evidenced by lower force production, extent and kinetics of shortening, and work output. Lower force was associated with lower energy expenditure related to Ca²⁺ cycling and to cross-bridge cycling. However, despite these changes, both mechanical and cross-bridge energy efficiency were unchanged. Our results show that cardiac hypertrophy is associated with impaired contractile performance and with preservation of energy efficiency. These findings provide direction for future investigations targeting metabolic and Ca²⁺ disturbances underlying cardiac mechanical and energetic impairment in primary cardiac hypertrophy.     

Functional morphology of the gills of the shortfin mako,Isurus oxyrinchus,a lamnid shark

This study examines the functional gill morphology of the shortfin mako, Isurus oxyrinchus, to determine the extent to which its gill structure is convergent with that of tunas for specializations required to increase gas exchange and withstand the forceful branchial flow induced by ram ventilation. Mako gill structure is also compared to that of the blue shark, Prionace glauca, an epipelagic species with lower metabolic requirements and a reduced dependence on fast, continuous swimming to ventilate the gills. The gill surface area of the mako is about one‐half that of a comparably sized tuna, but more than twice that of the blue shark and other nonlamnid shark species. Mako gills are also distinguished from those of other sharks by shorter diffusion distances and a more fully developed diagonal blood‐flow pattern through the gill lamellae, which is similar to that found in tunas. Although the mako lacks the filament and lamellar fusions of tunas and other ram‐ventilating teleosts, its gill filaments are stiffened by the elasmobranch interbranchial septum, and the lamellae appear to be stabilized by one to two vascular sacs that protrude from the lamellar surface and abut sacs of adjacent lamellae. Vasoactive agents and changes in vascular pressure potentially influence sac size, consequently effecting lamellar rigidity and both the volume and speed of water through the interlamellar channels. However, vascular sacs also occur in the blue shark, and no other structural elements of the mako gill appear specialized for ram ventilation. Rather, the basic elasmobranch gill design and pattern of branchial circulation are both conserved. Despite specializations that increase mako gill area and efficacy relative to other sharks, the basic features of the elasmobranch gill design appear to have limited selection for a larger gill surface area, and this may ultimately constrain mako aerobic performance in comparison to tunas. J. Morphol. 271:937–948, 2010. © 2010 Wiley‐Liss, Inc.     

A genome map of Salmonella enterica serovar Agona: numerous insertions and deletions reflecting the evolutionary history of a human pathogen

Salmonella enterica serovar Agona is an important zoonotic pathogen, causing serious human illness worldwide, but knowledge about its genetics and evolution, especially regarding the genomic events that might have contributed to the formation of S . Agona as an important pathogen, is lacking. As a first step toward understanding this pathogen and characterizing its genomic differences with other salmonellae, we constructed a physical map of S . Agona in strain SARB1 using I-CeuI, XbaI, AvrII and Tn 10 insertions with pulsed-field gel electrophoresis techniques. On the 4815-kb genomic map, we located 82 genes, revealed one inversion of about 1000 kb and resolved seven deletions and seven insertions ranging from 10 to 67 kb relative to the genome of Salmonella typhimurium LT2. These genomic features clearly distinguish S . Agona from other previously analyzed salmonellae and provide clues to the molecular basis for its genomic divergence. Additionally, these kinds of physical maps, combined with emerging high-speed sequencing technologies, such as the Solexa or SOLiD techniques, which require a pre-existing high-resolution physical map such as the S . Agona map reported here, will play important roles in genomic comparative studies of bacteria involving large numbers of strains.