Young Aphids Avoid Erroneous Dropping when Evading Mammalian Herbivores by Combining Input from Two Sensory Modalities

Mammalian herbivores may incidentally ingest plant-dwelling insects while foraging. Adult pea aphids (Acyrthosiphon pisum) avoid this danger by dropping off their host plant after sensing the herbivore's warm and humid breath and the vibrations it causes while feeding. Aphid nymphs may also drop (to escape insect enemies), but because of their slow movement, have a lower chance of finding a new plant. We compared dropping rates of first-instar nymphs with those of adults, after exposing pea aphids to different combinations of simulated mammalian breath and vibrations. We hypothesized that nymphs would compensate for the greater risk they face on the ground by interpreting more conservatively the mammalian herbivore cues they perceive. Most adults dropped in response to breath alone, but nymphs rarely did so. Breath stimulus accompanied by one concurrent vibrational stimulus, caused a minor rise in adult dropping rates. Adding a second vibration during breath had no additional effect on adults. The nymphs, however, relied on a combination of the two types of stimuli, with a threefold increase in dropping rates when the breath was accompanied by one vibration, and a further doubling of dropping rates when the second vibration was added. The age-specificity of the aphids' herbivore detection mechanism is probably an adaptation to the different cost of dropping for the different age groups. Relying on a combination of stimuli from two sensory modalities enables the vulnerable nymphs to avoid costly mistakes. Our findings emphasize the importance of the direct trophic effect of mammalian herbivory for plant-dwelling insects

Model for end-stage liver disease (MELD) exception guidelines: Results and recommendations from the MELD exception study group and conference (MESSAGE) for the approval of patients who need liver transplantation with diseases not considered by the standard MELD formula

No abstract.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/55914/1/20979_ftp.pd

Prevalence of hepatic iron overload and association with hepatocellular cancer in end-stage liver disease: results from the National Hemochromatosis Transplant Registry

Background : It is unclear whether mild to moderate iron overload in liver diseases other than hereditary haemochromatosis (HH) contributes to hepatocellular carcinoma. This study examined the association between hepatic iron grade and hepatocellular carcinoma in patients with end-stage liver disease of diverse aetiologies. Methods : The prevalence of hepatic iron overload and hepatocellular carcinoma was examined in 5224 patients undergoing liver transplantation. Explant pathology reports were reviewed for the underlying pathological diagnosis, presence of hepatocellular carcinoma and degree of iron staining. The distribution of categorical variables was studied using Χ 2 tests. Results : Both iron overload and hepatocellular carcinoma were the least common with biliary cirrhosis (1.8 and 2.8% respectively). Hepatocellular carcinoma was the most common in patients with hepatitis B (16.7%), followed by those with hepatitis C (15.1%) and HH (14.9%). In the overall cohort, any iron overload was significantly associated with hepatocellular carcinoma ( P =0.001), even after adjustment for the underlying aetiology of liver disease. The association between hepatic iron content and hepatocellular carcinoma was the strongest in patients with biliary cirrhosis ( P <0.001) and hepatitis C ( P <0.001). Conclusions : Iron overload is associated with hepatocellular carcinoma in patients with end-stage liver disease, suggesting a possible carcinogenic or cocarcinogenic role for iron in chronic liver disease.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75573/1/j.1478-3231.2007.01596.x.pd

Impact of viral replication inhibition by entecavir on peripheral T lymphocyte subpopulations in chronic hepatitis B patients

<p>Abstract</p> <p>Background</p> <p>To investigate dynamic fluctuations of serum viral load and peripheral T-lymphocyte subpopulations of chronic hepatitis B patients and their correlation during entecavir therapy.</p> <p>Methods</p> <p>Fifty-five patients received entecavir 0.5 mg/d therapy. Serum HBV DNA load was measured by Real-Time-PCR, and the levels of peripheral T-lymphocyte subpopulations by flow cytometry biweekly, every four weeks and every eight weeks during weeks 1–12, 13–24 and 24–48, respectively. Multilevel modelling was used to analyse the relationship between these variables.</p> <p>Results</p> <p>Of the 55 patients, all HBeAg positive and with detectable HBV DNA, the majority (81.8%) had serum levels of HBV DNA over 10⁷copies per milliliter. HBV viral load dropped sharply during the first two weeks. In 28 and 43 patients, the level became undetectable from week 24 and 48, respectively. Using pre-therapy level as the reference, a significant decrease in CD8⁺T cells and increase in CD4⁺T cells were found from week 12. Both parameters and CD4⁺/CD8⁺ratio steadily improved throughout the 48 weeks. Multilevel analyses showed that the level of decrement of HBV DNA was associated with the increment of T-lymphocyte activities only in the later period (4–48 week). After 4 weeks of therapy, for each log₁₀scale decrement of HBV DNA, the percentage of CD4⁺lymphocyte was increased by 0.49 and that of CD8⁺decreased by 0.51.</p> <p>Conclusion</p> <p>T-lymphocyte subpopulations could be restored partially by entecavir treatment in patients with chronic hepatitis B concurrently with reduction of viremia.</p

The Evolution of tRNA Genes in Drosophila

The structure and function of transfer RNA (tRNA) genes have been extensively studied for several decades, yet the general mechanisms controlling tRNA gene family evolution remain unclear, primarily because previous phylogenetics-based methods fail to distinguish between paralogs and orthologs that are highly similar in sequence. We have developed a system for identifying orthologs of tRNAs using flanking sequences to identify regions of conserved synteny and used it to annotate sets of orthologous tRNA genes across the 12 sequenced species of Drosophila. These data have allowed us to place the gains and losses of individual tRNA genes on each branch of the Drosophila tree and estimate rates of tRNA gene turnover. Our results show extensive rearrangement of the Drosophila tRNA gene complement over the last 60 My. We estimate a combined average rate of 2.18 ± 0.10 tRNA gene gains and losses per million years across the Drosophila lineage. We have identified 192 tRNAs that are ancestral to the genus, of which 157 are “core” tRNAs conserved in at least 11 of 12 extant species. We provide evidence that the core set of tRNA genes encode a nearly complete set of anticodons and have different properties from other “peripheral” tRNA genes, such as preferential location outside large tRNA clusters and higher sequence conservation. We also demonstrate that tRNA isoacceptor and alloacceptor changes by anticodon shifts have occurred several times in Drosophila, annotating 16 such events in functional tRNAs during the evolution of the genus

Rest, zest and my innovative best: sleep and mood as drivers of entrepreneurs’ innovative behavior

This study investigates the antecedents of an entrepreneur’s day-level innovative behavior. Drawing on 2,420 data points from a 10-day experience sampling study with 121 entrepreneurs, we find that sleep quality is a precursor to an entrepreneur’s subsequent innovative behavior, in accordance with the effort-recovery model. Moreover, sleep quality is positively related to high-activation positive moods (e.g., enthusiastic, inspired) and negatively related to high-activation negative moods (e.g., tension, anxiety). Our multilevel structural equation model indicates that high-activation positive moods mediate the relationship between sleep quality and innovative behavior on a given day. These results are relevant for managing entrepreneurial performance

Pros and Cons of Peginterferon Versus Nucleos(t)ide Analogues for Treatment of Chronic Hepatitis B

The emergence of new and more potent treatment options has markedly changed the treatment landscape of chronic hepatitis B. Both peginterferon and nucleos(t)ide analogues have considerable advantages and limitations, and current treatment guidelines refrain from clearly suggesting a first-line treatment option. Peginterferon offers the advantage of higher sustained response rates in both hepatitis B early antigen (HBeAg)-positive and HBeAg-negative patients, at the price of considerable side effects and high costs. Nucleos(t)ide analogues offer easy daily oral dosing, and newly registered agents can maintain viral suppression for prolonged treatment duration. However, relapse is common after therapy discontinuation and extended therapy therefore often necessary. Prolonged treatment with nucleos(t)ide analogues may enhance chances of virologic and serologic response at the potential cost of the emergence of viral resistance and side effects. Baseline and on-treatment prediction of response may help select patients for peginterferon therapy and can aid individualized treatment decisions concerning therapy continuation or discontinuation

Combined Evidence Annotation of Transposable Elements in Genome Sequences

Transposable elements (TEs) are mobile, repetitive sequences that make up significant fractions of metazoan genomes. Despite their near ubiquity and importance in genome and chromosome biology, most efforts to annotate TEs in genome sequences rely on the results of a single computational program, RepeatMasker. In contrast, recent advances in gene annotation indicate that high-quality gene models can be produced from combining multiple independent sources of computational evidence. To elevate the quality of TE annotations to a level comparable to that of gene models, we have developed a combined evidence-model TE annotation pipeline, analogous to systems used for gene annotation, by integrating results from multiple homology-based and de novo TE identification methods. As proof of principle, we have annotated “TE models” in Drosophila melanogaster Release 4 genomic sequences using the combined computational evidence derived from RepeatMasker, BLASTER, TBLASTX, all-by-all BLASTN, RECON, TE-HMM and the previous Release 3.1 annotation. Our system is designed for use with the Apollo genome annotation tool, allowing automatic results to be curated manually to produce reliable annotations. The euchromatic TE fraction of D. melanogaster is now estimated at 5.3% (cf. 3.86% in Release 3.1), and we found a substantially higher number of TEs (n = 6,013) than previously identified (n = 1,572). Most of the new TEs derive from small fragments of a few hundred nucleotides long and highly abundant families not previously annotated (e.g., INE-1). We also estimated that 518 TE copies (8.6%) are inserted into at least one other TE, forming a nest of elements. The pipeline allows rapid and thorough annotation of even the most complex TE models, including highly deleted and/or nested elements such as those often found in heterochromatic sequences. Our pipeline can be easily adapted to other genome sequences, such as those of the D. melanogaster heterochromatin or other species in the genus Drosophila