The physiological significance of the water soluble components of nervous tissue

Part I. The mechanisms of acetylcholine synthesis1) Both citrate and acetate can act as acetyl donors for choline acetylation by crude brain extracts.2) In order to demonstrate the action of acetate three conditions have to be observed: a) that acetate is not added as a contaminant of the ATP: b) that the enzymes bringing acetate into reaction are protected during extraction from the acetone - dried powder by cysteine: c) that a ten times higher level of coenzyme than for the citrate system is used.á) Citrate acts as an acetyl donor by breaking down to acetate and oxaloacetate. Mg, ATP and the coenzyme are essential for this reaction. The coenzyme requirement is low.4) Citrate can act in a similar manner in the acetylation of sulphanilamide. Probably acetate and oxaloacetate are not the only products of citrate dismutation.5 The citrate and acetate "priming reactions" carried out by the brain enzymes (in the absence of choline) can be coupled with a liver fraction (sulphanilamide condensing enzyme) to acetylate sulphanilamide.6) At least two steps are involved in enzymic acetylation. Activation of acetate (probably a coenzyme acetate complex) and condensation with the acetyl acceptor are the main enzymic steps.7) "Choline acetylase" includes more than one enzyme; it should only refer to the enzyme catalysing the condensation of active acetate with choline.8) The validity of studies on the distribution of "choline acetylase" in the nervous system is discussed. No change in the ability of various parts of the system to synthesise acetylcholine is expected since the "citrate enzyme" probably has a universal distribution.Part II: The Purification and Structure of Coenzyme A.1) Evidence is presented to prove the identity of th activator with the coenzyme of acetylation.2) The coenzyme is not responsible for the blue fluorescence described by Comline (1948).3) A method of purification, based on the acidic and reducing properties of the coenzyme is described.4) Acid hydrolysatevof the coenzyme contain a sulphur fragment which is probably identical with the Lactobacillus bulgaricus factor.5) Digestion of the coenzyme with an enzyme derived from rabbit spleen releases two phosphoruscontaining fragments which can be resynthesised to the coenzyme by a liver enzyme.6) Digestion of the coenzyme with a crude intestinal phosphatase releases three phosphorus-containing fragments which cannot be resynthesised to the coenzyme under the conditions described.7) The structure of the coenzyme is discussed

Where One Marketplace Closes, (Hopefully) Another Won\u27t Open: In Defense of FOSTA

Since federal law first acknowledged the crime of sex trafficking in 2000, the internet has exploded—and sex traffickers have taken note. Traffickers have gained a platform to sell their victims to a much larger audience and with greater ease. Posting victims’ advertisements online allows traffickers to drastically expand their customer base beyond the traditional street corner. Despite congressional attempts to criminalize sex traffickers and their beneficiaries since 2000, the internet persists as an effective conduit for sex traffickers to find customers. In 2018, Congress sought to remedy this by passing legislation that expanded criminal and civil liability to websites that knowingly participate in sex trafficking by hosting sex trafficking advertisements. In part, the Allow States and Victims to Fight Online Sex Trafficking Act (FOSTA) amends a law that was widely understood to provide websites with total immunity from claims arising out of third-party content. Concerned with the potential for criminal prosecutions, internet service providers criticize FOSTA as an infringement on their First Amendment right to free speech. They argue that the law forces them to censor third-party users’ content and that it improperly extends to legal speech. The First Amendment generally does not restrict the content of speech, however, and its protections do not extend to speech that solicits crime. This Note will argue that FOSTA does not violate the First Amendment and is constitutionally sound at its core because sex traffickers’ advertisements solicit crime

The Molecular Line Opacity of MgH in Cool Stellar Atmospheres

A new, complete, theoretical rotational and vibrational line list for the A-X electronic transition in MgH is presented. The list includes transition energies and oscillator strengths for all possible allowed transitions and was computed using the best available theoretical potential energies and dipole transition moment function with the former adjusted to account for experimental data. The A-X line list, as well as new line lists for the B'-X and the X-X (pure rovibrational) transitions, were included in comprehensive stellar atmosphere models for M, L, and T dwarfs and solar-type stars. The resulting spectra, when compared to models lacking MgH, show that MgH provides significant opacity in the visible between 4400 and 5600 Angstrom. Further, comparison of the spectra obtained with the current line list to spectra obtained using the line list constructed by Kurucz (1993) show that the Kurucz list significantly overestimates the opacity due to MgH particularly for the bands near 5150 and 4800 Angstrom with the discrepancy increasing with decreasing effective temperature.Comment: 10 pages, 4 figures, 3 table

The Molecular Continuum Opacity of MgH in Cool Stellar Atmospheres

The opacity due to photodissociation of 24MgH is investigated in the atmospheres of cool stars. The lowest two electronic transitions A 2Pi -- X 2Sigma+ and B' 2Sigma+ -- X 2 Sigma+ are considered where the cross sections for the latter were published previously (Weck, Stancil, & Kirby 2002) while the former are presented in this work. Model atmospheres calculated with the PHOENIX code are used to investigate the effect of the photodissociation opacity on spectra of cool stars. The A -- X photodissociation cross sections are obtained using a combination of ab initio and experimentally derived potential curves and dipole transition moments. Partial cross sections have been evaluated over the accessible wavelength range 1770-4560 Angstrom for all rotational transitions from the vibrational levels v''=0-11. Assuming a Boltzmann distribution of the rovibrational levels of the X 2Sigma+ state, LTE photodissociation cross sections are presented for temperatures between 1000 and 5000 K. Shape resonances, arising from rotational predissociation of quasi-bound levels of the A 2Pi state near threshold, characterize the LTE photodissociation cross sections. A sum rule is proposed as a check on the accuracy of the photodissociation calculations.Comment: 9 pages, 8 figure

Appetite for self-destruction: suicidal biting as a nest defense strategy in Trigona stingless bees

Self-sacrificial behavior represents an extreme and relatively uncommon form of altruism in worker insects. It can occur, however, when inclusive fitness benefits are high, such as when defending the nest. We studied nest defense behaviors in stingless bees, which live in eusocial colonies subject to predation. We introduced a target flag to nest entrances to elicit defensive responses and quantified four measures of defensivity in 12 stingless bee species in São Paulo State, Brazil. These included three Trigona species, which are locally known for their aggression. Species varied significantly in their attack probability (cross species range = 0–1, P < 0.001), attack latency (7.0–23.5 s, P = 0.002), biting duration of individual bees (3.5–508.7 s, P < 0.001), and number of attackers (1.0–10.8, P < 0.001). A “suicide” bioassay on the six most aggressive species determined the proportion of workers willing to suffer fatal damage rather than disengage from an intruder. All six species had at least some suicidal individuals (7–83 %, P < 0.001), reaching 83 % in Trigona hyalinata. Biting pain was positively correlated with an index of overall aggression (P = 0.002). Microscopic examination revealed that all three Trigona species had five sharp teeth per mandible, a possible defensive adaptation and cause of increased pain. Suicidal defense via biting is a new example of self-sacrificial altruism and has both parallels and differences with other self-sacrificial worker insects, such as the honey bee. Our results indicate that suicidal biting may be a widespread defense strategy in stingless bees, but it is not universal

“Wayside Houses of Ill-Repute” – Diverticular Disease of the Colon

A diverticulum is simply a blind pouch and it can occur in any section of the alimentary tract; this article concentrates on those arising from the large bowel.The question of how diverticulae are produced was for many years the subject of pure conjecture rather than of scientific proof. If we turn back the pages of medical journals over the past century, we see many shifts in the emphasis of man’s efforts to elucidate the cause of acquired colonic diverticular disease. The current theory is that abnormal inter-haustral contractions of rings of thickened muscle result in the development of very high intra-colonic pressures in response to certain specific stimuli, the most important being morphine and prostigmine. By contrast, “probanthine” and atropine tend to abolish the pressures.I must stress that basal pressures are similar in patients with diverticular disease and in normal controls. (This tends to refute any close casual relationship between the “spastic colon" and diverticular disease.) It is only in response to certain stimuli that the abnormal intraluminal pressures may be recorded.One important practical point is that the above facts represent prima facie evidence against using morphine to alleviate the pain of acute diverticulitis

Range-separated density-functional theory with random phase approximation: detailed formalism and illustrative applications

Using Green-function many-body theory, we present the details of a formally exact adiabatic-connection fluctuation-dissipation density-functional theory based on range separation, which was sketched in Toulouse, Gerber, Jansen, Savin and Angyan, Phys. Rev. Lett. 102, 096404 (2009). Range-separated density-functional theory approaches combining short-range density functional approximations with long-range random phase approximations (RPA) are then obtained as well-identified approximations on the long-range Green-function self-energy. Range-separated RPA-type schemes with or without long-range Hartree-Fock exchange response kernel are assessed on rare-gas and alkaline-earth dimers, and compared to range-separated second-order perturbation theory and range-separated coupled-cluster theory.Comment: 15 pages, 3 figures, 2 table

Shining new light on mammalian diving physiology using wearable near-infrared spectroscopy

Investigation of marine mammal dive-by-dive blood distribution and oxygenation has been limited by a lack of non-invasive technology for use in freely diving animals. Here, we developed a non-invasive near-infrared spectroscopy (NIRS) device to measure relative changes in blood volume and haemoglobin oxygenation continuously in the blubber and brain of voluntarily diving harbour seals. Our results show that seals routinely exhibit preparatory peripheral vasoconstriction accompanied by increased cerebral blood volume approximately 15 s before submersion. These anticipatory adjustments confirm that blood redistribution in seals is under some degree of cognitive control that precedes the mammalian dive response. Seals also routinely increase cerebral oxygenation at a consistent time during each dive, despite a lack of access to ambient air. We suggest that this frequent and reproducible reoxygenation pattern, without access to ambient air, is underpinned by previously unrecognised changes in cerebral drainage. The ability to track blood volume and oxygenation in different tissues using NIRS will facilitate a more accurate understanding of physiological plasticity in diving animals in an increasingly disturbed and exploited environment

T cell-mediated oral tolerance is intact in germ-free mice

Commensal enteric bacteria stimulate innate immune cells and increase numbers of lamina propria and mesenteric lymph node (MLN) T and B lymphocytes. However, the influence of luminal bacteria on acquired immune function is not understood fully. We investigated the effects of intestinal bacterial colonization on T cell tolerogenic responses to oral antigen compared to systemic immunization. Lymphocytes specific for ovalbumin–T cell receptor (OVA–TCR Tg+) were transplanted into germ-free (GF) or specific pathogen-free (SPF) BALB/c mice. Recipient mice were fed OVA or immunized subcutaneously with OVA peptide (323–339) in complete Freund's adjuvant (CFA). Although the efficiency of transfer was less in GF recipients, similar proportions of cells from draining peripheral lymph node (LN) or MLN were proliferating 3–4 days later in vivo in GF and SPF mice. In separate experiments, mice were fed tolerogenic doses of OVA and then challenged with an immunogenic dose of OVA 4 days later. Ten days after immunization, lymphocytes were restimulated with OVA in vitro to assess antigen-specific proliferative responses. At both high and low doses of OVA, cells from both SPF and GF mice fed OVA prior to immunization had decreased proliferation compared to cells from control SPF or GF mice. In addition, secretion of interferon (IFN)-γ and interleukin (IL)-10 by OVA–TCR Tg+ lymphocytes was reduced in both SPF and GF mice fed OVA compared to control SPF or GF mice. Unlike previous reports indicating defective humoral responses to oral antigen in GF mice, our results indicate that commensal enteric bacteria do not enhance the induction of acquired, antigen-specific T cell tolerance to oral OVA