Electrochemistry of potential bioreductive alkylating quinones : Part 2. Electrochemical properties of 2,5-bis(1-aziridinyl)-3,6-bis(ethoxycarbonylamino)-1,4-benzoquinone and some model compounds

The reduction mechanism of 2,5-bis(1-aziridinyl)-3,6-bis(ethoxycarbonylamino)-1,4-benzoquinone (Diaziquone, AZQ) and several model compounds of the mono- and bis(1-aziridinyl)quinone type at the dropping mercury electrode in aqueous solutions was studied. In addition, the influence of methyl substitution of the aziridinyl moiety at the 2-position on the protonation of the aziridine nitrogen was investigated. Substituent effects on quinone reduction and aziridine protonation prior to and following quinone reduction were studied qualitatively

Electrochemistry of potentially bioreductive alkylating quinones : Part 1. Electrochemical properties of relatively simple quinones, as model compounds of mitomycin- and aziridinylquinone-type antitumour agents

The influence of methyl-, hydroxy and amino substituents on the electrochemical behaviour of simple 1,4-naphtho-and 1,4-benzoquinones, model compounds of many quinoid antitumour agents, in aqueous media was studied. Significant changes in electrochemical behaviour were observed, potentially the result of a change in the electron density of the quinone moiety, pre- or post-protonation of substituents, hydrogen bond formation, tautomerization reactions and steric interactions between the quinone moiety and substituents. The information obtained was of benefit in the elucidation of the reduction mechanisms of quinoid antitumour agents such as aziridnylquinones and mitomycins

First record of the genus Periclimenaeus borradaile, 1815 (decapoda : palaemoniidae : pontoniinae) in the northeastern Atlantic, with the description of a new species, Periclimenaeus aurae

A new species of Periclimenaeus is described from Madeira Island, in the northeastern Atlantic Ocean. It is closest to P. pearsei Holthuis, 1951 from the western Atlantic, but it can be distinguished by the shape of rostrum, the size of exopod in relation to endopod in third maxilliped, the relation between the carpus and the chela of pereiopod 1, the relative size of second pereiopod minor chel a, and the number of setae on appendix masculina. This is the first record of the genus Periclimenaeus in the eastern Atlantic.info:eu-repo/remantics/publishedVersio

Wikipedia as an encyclopaedia of life

In his 2003 essay E O Wilson outlined his vision for an “encyclopaedia of life” comprising “an electronic page for each species of organism on Earth”, each page containing “the scientific name of the species, a pictorial or genomic presentation of the primary type specimen on which its name is based, and a summary of its diagnostic traits.” Although the “quiet revolution” in biodiversity informatics has generated numerous online resources, including some directly inspired by Wilson's essay (e.g., "http://ispecies.org":http://ispecies.org, "http://www.eol.org":http://www.eol.org), we are still some way from the goal of having available online all relevant information about a species, such as its taxonomy, evolutionary history, genomics, morphology, ecology, and behaviour. While the biodiversity community has been developing a plethora of databases, some with overlapping goals and duplicated content, Wikipedia has been slowly growing to the point where it now has over 100,000 pages on biological taxa. My goal in this essay is to explore the idea that, largely independent of the efforts of biodiversity informatics and well-funded international efforts, Wikipedia ("http://en.wikipedia.org/wiki/Main_Page":http://en.wikipedia.org/wiki/Main_Page) has emerged as potentially the best platform for fulfilling E O Wilson’s vision

On the Names of Penaeus setiferus (L.) and Penaeus schmitti Burkenroad

Dr. Gordon Gunter, who sent me the manuscript of his paper “Specific Names of the Atlantic American White Shrimp (Family Penaeidae)” for comment was so kind to allow me to have my reactions to it published simultaneously with it. Unfortunately I cannot agree with Doctor Gunter’s views on the scientific names that should be used for the two Atlantic species of White Shrimp. In the first place I believe that Doctor Gunter’s suggestion that the northern species should be known at Penaeus fluviatilis Say and the southern as P. setiferus (L.) instead of respectively P. setiferus (L.) and P. schmitti Burkenroad, is not in accordance with the International Code of Zoological Nomenclature. Second I believe it against the interest of stability and uniformity of nomenclature to switch a well-known name from one economically important species to another, as this will inevitably lead to serious confusion, and will especially cause difficulties to non-taxonomists

On the Names of Penaeus setiferus (L.) and Penaeus schmitti Burkenroad

Dr. Gordon Gunter, who sent me the manuscript of his paper “Specific Names of the Atlantic American White Shrimp (Family Penaeidae)” for comment was so kind to allow me to have my reactions to it published simultaneously with it. Unfortunately I cannot agree with Doctor Gunter’s views on the scientific names that should be used for the two Atlantic species of White Shrimp. In the first place I believe that Doctor Gunter’s suggestion that the northern species should be known at Penaeus fluviatilis Say and the southern as P. setiferus (L.) instead of respectively P. setiferus (L.) and P. schmitti Burkenroad, is not in accordance with the International Code of Zoological Nomenclature. Second I believe it against the interest of stability and uniformity of nomenclature to switch a well-known name from one economically important species to another, as this will inevitably lead to serious confusion, and will especially cause difficulties to non-taxonomists

Optical manipulation of sphingolipid biosynthesis using photoswitchable ceramides

Ceramides are central intermediates of sphingolipid metabolism that also function as potent messengers in stress signaling and apoptosis. Progress in understanding how ceramides execute their biological roles is hampered by a lack of methods to manipulate their cellular levels and metabolic fate with appropriate spatiotemporal precision. Here, we report on clickable, azobenzene-containing ceramides, caCers, as photoswitchable metabolic substrates to exert optical control over sphingolipid production in cells. Combining atomic force microscopy on model bilayers with metabolic tracing studies in cells, we demonstrate that light-induced alterations in the lateral packing of caCers lead to marked differences in their metabolic conversion by sphingomyelin synthase and glucosylceramide synthase. These changes in metabolic rates are instant and reversible over several cycles of photoswitching. Our findings disclose new opportunities to probe the causal roles of ceramides and their metabolic derivatives in a wide array of sphingolipid-dependent cellular processes with the spatiotemporal precision of light