Nachweis der Bisulfit-Addukte (α-Oxysulfonsäuren) von Carbonylverbindungen in den mit SO2 behandelten Erbsenkeimlingen

Summary The intoxication of 15-day-old green pea seedlings with 1% gaseous SO₂ causes an important concentration fall of some free ketoacids (pyruvic, oxalacetic, -ketoglutaric) and of glyceraldehyde in the roots and shoots. This fall is a consequence of the reaction of these carbonyl compounds with SO₂ in the plant tissue under the formation of bisulphite adducts (-hydroxysulfonic acids), which have been chemically proved and quantitatively estimated.     

Influence of epoxides of androstane series on some effects of cortisol

Zusammenfassung Auf der Basis von Struktur-Aktivitätsuntersuchungen verschiedener Epoxyden der Androstanreihe konnte gezeigt werden, dass die Antiglucocorticoid-Eigenschaften solcher Verbindungen von einer besonders spezifischen Struktur abhängig sind.     

A new genus and four new species of onchidiid slugs from South-East Asia (Mollusca: Gastropoda: Pulmonata: Onchidiidae)

The taxonomy of the Onchidiidae has remained extremely confusing for decades. As part of an on-going systematic revision of the entire family, a new genus, Melayonchis Dayrat and Goulding gen. nov., and four new species (Melayonchis eloisae Dayrat sp. nov., Melayonchis siongkiati Dayrat and Goulding sp. nov., Melayonchis annae Dayrat sp. nov., and Melayonchis aileenae Dayrat and Goulding sp. nov.) are described. Species are delineated using an integrative approach, based on morphological characters and DNA sequences. First-hand field observations and pictures of live animals are provided in order to help future species identification. All four Melayonchis species live in mangrove forests. The geographic distribution of Melayonchis ranges from the Andaman Sea to the South China Sea through the Strait of Malacca. Records are based on entirely new collections from the Andaman Islands, Peninsular Malaysia, Singapore, Brunei Darussalam and Vietnam. The nomenclature of all existing onchidiid species- and genus-group names from that region is addressed, as well as intraspecific character variation within Melayonchis.

www.zoobank.org/urn:lsid:zoobank.org:pub:671922DB-C6C1-44A5-B2CD-A3A3127CB668     

Function and evolution of channels and transporters in photosynthetic membranes

Chloroplasts from land plants and algae originated from an endosymbiotic event, most likely involving an ancestral photoautotrophic prokaryote related to cyanobacteria. Both chloroplasts and cyanobacteria have thylakoid membranes, harboring pigment-protein complexes that perform the light-dependent reactions of oxygenic photosynthesis. The composition, function and regulation of these complexes have thus far been the major topics in thylakoid membrane research. For many decades, we have also accumulated biochemical and electrophysiological evidence for the existence of solute transthylakoid transport activities that affect photosynthesis. However, research dedicated to molecular identification of the responsible proteins has only recently emerged with the explosion of genomic information. Here we review the current knowledge about channels and transporters from the thylakoid membrane of Arabidopsis thaliana and of the cyanobacterium Synechocystis sp. PCC 6803. No homologues of these proteins have been characterized in algae, although similar sequences could be recognized in many of the available sequenced genomes. Based on phylogenetic analyses, we hypothesize a host origin for most of the so far identified Arabidopsis thylakoid channels and transporters. Additionally, the shift from a non-thylakoid to a thylakoid location appears to have occurred at different times for different transport proteins. We propose that closer control of and provision for the thylakoid by products of the host genome has been an ongoing process, rather than a one-step event. Some of the proteins recruited to serve in the thylakoid may have been the result of the increased specialization of its pigment-protein composition and organization in green plants.     

Two-photon laser spectroscopy of antiprotonic helium and the antiproton-to-electron mass ratio

Physical laws are believed to be invariant under the combined transformations of charge, parity and time reversal (CPT symmetry). This implies that an antimatter particle has exactly the same mass and absolute value of charge as its particle counterpart. Metastable antiprotonic helium (pHe(+)) is a three-body atom consisting of a normal helium nucleus, an electron in its ground state and an antiproton (p) occupying a Rydberg state with high principal and angular momentum quantum numbers, respectively n and l, such that n?≈?l?+?1?≈?38. These atoms are amenable to precision laser spectroscopy, the results of which can in principle be used to determine the antiproton-to-electron mass ratio and to constrain the equality between the antiproton and proton charges and masses. Here we report two-photon spectroscopy of antiprotonic helium, in which p(3)He(+) and p(4)He(+) isotopes are irradiated by two counter-propagating laser beams. This excites nonlinear, two-photon transitions of the antiproton of the type (n, l)?→?(n?-?2, l?-?2) at deep-ultraviolet wavelengths (λ = 139.8, 193.0 and 197.0?nm), which partly cancel the Doppler broadening of the laser resonance caused by the thermal motion of the atoms. The resulting narrow spectral lines allowed us to measure three transition frequencies with fractional precisions of 2.3-5 parts in 10(9). By comparing the results with three-body quantum electrodynamics calculations, we derived an antiproton-to-electron mass ratio of 1,836.1526736(23), where the parenthetical error represents one standard deviation. This agrees with the proton-to-electron value known to a similar precision.     

The experimenters' regress: from skepticism to argumentation

Harry Collins' central argument about experimental practice revolves around the thesis that facts can only be generated by good instruments but good instruments can only be recognized as such if they produce facts. This is what Collins calls the experimenters' regress. For Collins, scientific controversies cannot be closed by the ‘facts’ themselves because there are no formal criteria independent of the outcome of the experiment that scientists can apply to decide whether an experimental apparatus works properly or not.No one seems to have noticed that the debate is in fact a rehearsal of the ancient philosophical debate about skepticism. The present article suggests that the way out of radical skepticism offered by the so-called mitigated skeptics is a solution to the problem of consensus formation in science.     

Pyruvate kinase activity in brain,liver and brown adipose tissue and the effect of cortisone in suckling rats

Zusammenfassung Die Pyruvatkinaseaktivität wurde im Gehirn und in den Muskeln von Ratten während der Entwicklung bestimmt. Die Aktivität war in Feten höher als in säugenden Jungen und stieg dann wieder an. Kortisonacetat (5 mg · 100 g/Tag, 3 Tage) erhöht die Pyruvatkinaseaktivität am 10. Tag im braunen Fettgewebe und erniedrigt sie in der Leber. Eine hohe Fettdiät, vom 14. Tag an gefüttert, hat denselben Effekt am 30. Tag. Das Muskel- und Gehirnenzym kann man durch hohe Fettdiät oder Kortison nicht verändern.     

Maternal defensive behavior of mountain goats against predation by golden eagles

Maternal defensive behavior against predators may appear risky but is common in many species. Herein we describe maternal defensive behavior of mountain goats ( Oreamnos americanus ) against Golden Eagle ( Aquila chrysaetos ) predatory attempts. We found that Golden Eagles attacked goats in 1.9% of sightings ( n = 311 sightings of active Golden Eagles over 12 years) but were never successful. Mothers always defended their young against Golden Eagle attacks. Predation by Golden Eagles on young-of-the-year appears low for most ungulate species, including mountain goats. The benefits of defending offspring against eagles are likely high in ungulates, and we would therefore expect selection to favor maternal defensive behavior.