Avoiding death by autophagy: interactions of Listeria monocytogenes with the macrophage autophagy system

Autophagy restricts the growth of a variety of intracellular pathogens. However, cytosol-adapted pathogens have evolved ways to evade restriction by this innate immune mechanism. Listeria monocytogenes is a Gram-positive bacterial pathogen that utilizes a cholesterol-dependent pore-forming toxin, listeriolysin O (LLO), to escape from the phagosome. Autophagy targets L. monocytogenes in LLO-damaged phagosomes and also in the cytosol under some experimental conditions. However, this bacterium has evolved multiple mechanisms to evade restriction by autophagy, including actin-based motility in the cytosol and an as yet undefined mechanism mediated by bacterial phospholipases C (PLCs). A population of L. monocytogenes with inefficient LLO activity forms Spacious Listeria-containing Phagosomes (SLAPs), which are autophagosome-like compartments that do not mature, allowing slow bacterial growth within enlarged vesicles. SLAPs may represent a stalemate between bacterial LLO action and the host autophagy system, resulting in persistent infection.     

Detection and subtyping of Herpes simplex virus in clinical samples by LightCycler PCR, enzyme immunoassay and cell culture

Background  

Prompt laboratory diagnosis of Herpes simplex virus (HSV) infection facilitates patient management and possible initiation of antiviral therapy. In our laboratory, which receives various specimen types for detection of HSV, we use enzyme immunoassay (EIA) for rapid detection and culture of this virus. The culture of HSV has traditionally been accepted as the diagnostic 'gold standard'. In this study, we compared the use of real time PCR (LightCycler) for amplification, detection and subtyping of specific DNA with our in-house developed rapid and culture tests for HSV.     

Child‐Specific Thoracic Gas Volume Prediction Equations for Air‐Displacement Plethysmography

Objective: To develop child‐specific thoracic gas volume (TGV) prediction equations for use in air‐displacement plethysmography in 6‐ to 17‐year‐old children. Research Methods and Procedures: Study 1 developed TGV prediction equations using anthropometric variables after completing a measured TGV and air‐displacement plethysmography test in 224 healthy boys and girls (11.2 ± 3.2 years, 45.3 ± 18.7 kg, 149.9 ± 18.5 cm). Study 2 cross‐validated the prediction equations in a separate cohort of 62 healthy boys and girls (11.2 ± 3.4 years, 44.2 ± 15.3 kg, 149.4 ± 19.3 cm). Results: In Study 1 (development of TGV prediction equations), the quadratic relationship using height as the independent variable and the measured TGV as the dependent variable yielded the highest adjusted R² and the lowest SE of estimate in both genders, thus producing the following prediction equations: TGV = 0.00056 × H² ? 0.12422 × H + 8.15194 (boys) and TGV = 0.00044 × H² ? 0.09220 × H + 6.00305 (girls). In Study 2 (cross‐validation), no significant difference between the predicted and measured TGVs (?0.018 ± 0.377 liters) was observed. The regression between the measured TGV and the predicted TGV yielded a slope and intercept that did not significantly differ from the line of identity. Prediction accuracy was good as indicated by a high R² (0.862) and low SE of estimate (0.369 liters). Discussion: The new child‐specific TGV prediction equations accurately, precisely, and without bias estimated the actual TGV of 6‐ to 17‐year‐old children.     

Evolution of gene expression in the Drosophila olfactory system

Host plant shifts by phytophagous insects play a key role in insect evolution and plant ecology. Such shifts often involve major behavioral changes as the insects must acquire an attraction and/or lose the repulsion to the new host plant's odor and taste. The evolution of chemotactic behavior may be due, in part, to gene expression changes in the peripheral sensory system. To test this hypothesis, we compared gene expression in the olfactory organs of Drosophila sechellia, a narrow ecological specialist that feeds on the fruit of Morinda citrifolia, with its close relatives Drosophila simulans and Drosophila melanogaster, which feed on a wide variety of decaying plant matter. Using whole-genome microarrays and quantitative polymerase chain reaction, we surveyed the entire repertoire of Drosophila odorant receptors (ORs) and odorant-binding proteins (OBPs) expressed in the antennae. We found that the evolution of OR and OBP expression was accelerated in D. sechellia compared both with the genome average in that species and with the rate of OR and OBP evolution in the other species. However, some of the gene expression changes that correlate with D. sechellia's increased sensitivity to Morinda odorants may predate its divergence from D. simulans. Interspecific divergence of olfactory gene expression cannot be fully explained by changes in the relative abundance of different sensilla as some ORs and OBPs have evolved independently of other genes expressed in the same sensilla. A number of OR and OBP genes are upregulated in D. sechellia compared with its generalist relatives. These genes include Or22a, which likely responds to a key odorant of M. citrifolia, and several genes that are yet to be characterized in detail. Increased expression of these genes in D. sechellia may have contributed to the evolution of its unique chemotactic behavior.     

Design, synthesis, and evaluation of fused heterocyclic analogs of SCH 58261 as adenosine A2A receptor antagonists

SCH 58261 is a reported adenosine A_2A receptor antagonist which is active in rat in vivo models of Parkinson’s Disease upon ip administration. However, it has poor selectivity versus the A₁ receptor and does not demonstrate oral activity. Quinoline analogs have improved upon the selectivity and pharmacokinetics of SCH 58261, but were difficult to handle due to poor aqueous solubility. We report the design and synthesis of fused heterocyclic analogs of SCH 58261 with aqueous solubility as well as improved A_2A receptor binding selectivity and pharmacokinetic properties. In particular, the tetrahydronaphthyridine 4s has excellent A_2A receptor in vitro binding affinity and selectivity, is active orally in a rat in vivo model of Parkinson’s Disease, and has aqueous solubility of 100 μM at physiological pH.     

Epigenetic and phenotypic consequences of a truncation disrupting the imprinted domain on distal mouse chromosome 7

The distal end of mouse chromosome 7 (Chr 7) contains a large cluster of imprinted genes. In this region two cis-acting imprinting centers, IC1 (H19 DMR) and IC2 (KvDMR1), define proximal and distal subdomains, respectively. To assess the functional independence of IC1 in the context of Chr 7, we developed a recombinase-mediated chromosome truncation strategy in embryonic stem cells and generated a terminal deletion allele, DelTel7, with a breakpoint in between the two subdomains. We obtained germ line transmission of the truncated Chr 7 and viable paternal heterozygotes, confirming the absence of developmentally required paternally expressed genes distal of Ins2. Conversely, maternal transmission of DelTel7 causes a midgestational lethality, consistent with loss of maternally expressed genes in the IC2 subdomain. Expression and DNA methylation analyses on DelTel7 heterozygotes demonstrate the independent imprinting of IC1 in absence of the entire IC2 subdomain. The evolutionarily conserved linkage between the subdomains is therefore not required for IC1 imprinting on Chr 7. Importantly, the developmental phenotype of maternal heterozygotes is rescued fully by a paternally inherited deletion of IC2. Thus, all the imprinted genes located in the region and required for normal development are silenced by an IC2-dependent mechanism on the paternal allele.     

Estimates for worldwide laboratory animal use in 2005

Animal experimentation continues to generate public and political concern worldwide. Relatively few countries collate and publish animal use statistics, yet this is a first and essential step toward public accountability and an informed debate, as well as being important for effective policy-making and regulation. The implementation of the Three Rs (replacement, reduction and refinement of animal experiments) should be expected to result in a decline in animal use, but without regular, accurate statistics, this cannot be monitored. Recent estimates of worldwide annual laboratory animal use are imprecise and unsubstantiated, ranging from 28-100 million. We collated data for 37 countries that publish national statistics, and standardised these against the definitions of 'animals', 'purposes' and 'experiments' used in European Union Directive 86/609/EEC. We developed and applied a statistical model, based on publication rates, for a further 142 countries. This yielded our most conservative estimate of global animal use: 58.3 million animals in 179 countries. However, this figure excludes several uses and forms of animals that are included in the statistics of some countries. With the data available, albeit for only a few countries, we also produced, by extrapolation, a more comprehensive global estimate that includes animals killed for the provision of tissues, animals used to maintain genetically-modified strains, and animals bred for laboratory use but killed as surplus to requirements. For a number of reasons that are explained, this more-comprehensive figure of 115.3 million animals is still likely to be an underestimate.