The snail-killing flies of Alaska (Diptera: Sciomyzidae)

Information is given on the geographic distribution, habitat preferences, larval foods, and immature stages for 57 species of 9 genera of Sciomyzidae known to occur in Alaska. An illustrated key to adults is included. Alaska as a habitat for sciomyzid flies is discussed, and information on feeding habits of the larvae is summarized

Positive mRNA Translational Control in Germ Cells by Initiation Factor Selectivity

Ultimately, the production of new proteins in undetermined cells pushes them to new fates. Other proteins hold a stem cell in a mode of self-renewal. In germ cells, these decision-making proteins are produced largely from translational control of preexisting mRNAs. To date, all of the regulation has been attributed to RNA binding proteins (RBPs) that repress mRNAs in many models of germ cell development (Drosophila, mouse, C. elegans, and Xenopus). In this review, we focus on the selective, positive function of translation initiation factors eIF4E and eIF4G, which recruit mRNAs to ribosomes upon derepression. Evidence now shows that the two events are not separate but rather are coordinated through composite complexes of repressors and germ cell isoforms of eIF4 factors. Strikingly, the initiation factor isoforms are themselves mRNA selective. The mRNP complexes of translation factors and RBPs are built on specific populations of mRNAs to prime them for subsequent translation initiation. Simple rearrangement of the partners causes a dormant mRNP to become synthetically active in germ cells when and where they are required to support gametogenesis

Sharpenings of Li's criterion for the Riemann Hypothesis

Exact and asymptotic formulae are displayed for the coefficients $\lambda_n$ used in Li's criterion for the Riemann Hypothesis. For $n \to \infty$ we obtain that if (and only if) the Hypothesis is true, $\lambda_n \sim n(A \log n +B)$ (with $A>0$ and $B$ explicitly given, also for the case of more general zeta or $L$-functions); whereas in the opposite case, $\lambda_n$ has a non-tempered oscillatory form.Comment: 10 pages, Math. Phys. Anal. Geom (2006, at press). V2: minor text corrections and updated reference

Cap-Independent Translation Promotes C. elegans Germ Cell Apoptosis through Apaf-1/CED-4 in a Caspase-Dependent Mechanism

Apoptosis is a natural process during animal development for the programmed removal of superfluous cells. During apoptosis general protein synthesis is reduced, but the synthesis of cell death proteins is enhanced. Selective translation has been attributed to modification of the protein synthesis machinery to disrupt cap-dependent mRNA translation and induce a cap-independent mechanism. We have previously shown that disruption of the balance between cap-dependent and cap-independent C. elegans eIF4G isoforms (IFG-1 p170 and p130) by RNA interference promotes apoptosis in developing oocytes. Germ cell apoptosis was accompanied by the appearance of the Apaf-1 homolog, CED-4. Here we show that IFG-1 p170 is a native substrate of the worm executioner caspase, CED-3, just as mammalian eIF4GI is cleaved by caspase-3. Loss of Bcl-2 function (ced-9ts) in worms induced p170 cleavage in vivo, coincident with extensive germ cell apoptosis. Truncation of IFG-1 occurred at a single site that separates the cap-binding and ribosome-associated domains. Site-directed mutagenesis indicated that CED-3 processes IFG-1 at a non-canonical motif, TTTD456. Coincidentally, the recognition site was located 65 amino acids downstream of the newly mapped IFG-1 p130 start site suggesting that both forms support cap-independent initiation. Genetic evidence confirmed that apoptosis induced by loss of ifg-1 p170 mRNA was caspase (ced-3) and apoptosome (ced-4/Apaf-1) dependent. These findings support a new paradigm in which modal changes in protein synthesis act as a physiological signal to initiate cell death, rather than occur merely as downstream consequences of the apoptotic event

Self-assembly of phosphate fluorosurfactants in carbon dioxide

Anionic phosphodiester surfactants, possessing either two fluorinated chains (F/F) or one hydrocarbon chain and one fluorinated chain (H/F), were synthesized and evaluated for solubility and self-assembly in liquid and supercritical carbon dioxide. Several surfactants, of both F/F and EUF types and having varied counterions, were found to be capable of solubilizing water-in-CO2 (W/C), via the formation of microemulsions, expanding upon the family of phosphate fluorosurfactants already found to stabilize W/C microemulsions. Small-angle neutron scattering was used to directly characterize the microemulsion particles at varied temperatures, pressures, and water loadings, revealing behavior consistent with previous results on W/C microemulsions

Base editing repairs an SGCA mutation in human primary muscle stem cells

Skeletal muscle can regenerate from muscle stem cells and their myogenic precursor cell progeny, myoblasts. However, precise gene editing in human muscle stem cells for autologous cell replacement therapies of untreatable genetic muscle diseases has not yet been reported. Loss-of-function mutations in SGCA, encoding α-sarcoglycan, cause limb-girdle muscular dystrophy 2D/R3, an early onset, severe and rapidly progressive form of muscular dystrophy affecting equally girls and boys. Patients suffer from muscle degeneration and atrophy affecting the limbs, respiratory muscles, and the heart. We isolated human muscle stem cells from two donors with the common SGCA c.157G>A mutation affecting the last coding nucleotide of exon 2. We found that c.157G>A is an exonic splicing mutation that induces skipping of two co-regulated exons. Using adenine base editing, we corrected the mutation in the cells from both donors with >90% efficiency, thereby rescuing the splicing defect and α-sarcoglycan expression. Base edited patient cells regenerated muscle and contributed to the Pax7 positive satellite cell compartment in vivo in mouse xenografts. We hereby provide the first evidence that autologous gene repaired human muscle stem cells can be harnessed for cell replacement therapies of muscular dystrophies. ONE SENTENCE SUMMARY: Patient primary muscle stems cells gene repaired with >90% efficiency by base editing maintain their regenerative properties for autologous cell replacement therapies of muscular dystrophy

Neuroscience, Ethics, and National Security: The State of the Art

Military involvement and research in neuroscience generates unique ethical, legal, and social issues that require careful elucidation and consideration in order to align the potentially conflicting needs of national defense, public interest, and scientific progress

The Mind and the Machine. On the Conceptual and Moral Implications of Brain-Machine Interaction

Brain-machine interfaces are a growing field of research and application. The increasing possibilities to connect the human brain to electronic devices and computer software can be put to use in medicine, the military, and entertainment. Concrete technologies include cochlear implants, Deep Brain Stimulation, neurofeedback and neuroprosthesis. The expectations for the near and further future are high, though it is difficult to separate hope from hype. The focus in this paper is on the effects that these new technologies may have on our ‘symbolic order’—on the ways in which popular categories and concepts may change or be reinterpreted. First, the blurring distinction between man and machine and the idea of the cyborg are discussed. It is argued that the morally relevant difference is that between persons and non-persons, which does not necessarily coincide with the distinction between man and machine. The concept of the person remains useful. It may, however, become more difficult to assess the limits of the human body. Next, the distinction between body and mind is discussed. The mind is increasingly seen as a function of the brain, and thus understood in bodily and mechanical terms. This raises questions concerning concepts of free will and moral responsibility that may have far reaching consequences in the field of law, where some have argued for a revision of our criminal justice system, from retributivist to consequentialist. Even without such a (unlikely and unwarranted) revision occurring, brain-machine interactions raise many interesting questions regarding distribution and attribution of responsibility

Predatory capacity of a shorefly, Ochthera chalybescens, on malaria vectors

<p>Abstract</p> <p>Background</p> <p>Since <it>Ochthera chalybescens </it>had been reported to prey on African malaria vectors, the predatory capacity of adults of this species on <it>Anopheles gambiae </it>sensu stricto was explored.</p> <p>Method</p> <p>Predatory capacity of this fly on <it>A. gambiae </it>s.s. was tested at all developmental stages, including the adult stage in the laboratory setting. Effects of water depth on its predatory capacity were also examined.</p> <p>Results</p> <p>This study revealed that <it>O. chalybescens </it>preyed on mosquitoes at all life stages except eggs. It was able to prey on an average of 9.8 to 18.8 mosquito larvae in 24 hrs. Mosquito larva size and water depth did not affect predatory capacity. However, the predacious fly preyed on significantly more 2^nd-instar larvae than on pupae when larvae and pupae were both available.</p> <p>Conclusion</p> <p><it>Ochthera chalybescens </it>is, by all indications, an important predator of African malaria vectors.</p