4-Substituted anilides as selective melatonin MT2 receptor agonists

A series of 4-substituted anilides with human melatonergic affinity is reported. Butyramides 26, 39, 42, 52, 57, and 58 all demonstrated subnanomolar MT(2) binding affinity and MT(2) selectivity of at least 70-fold over the MT(1) receptor. Compound 26 demonstrated full agonism at the MT(2) receptor.     

Altered ligand rebinding kinetics due to distal-side effects in hemoglobin chico (Lysbeta66(E10) --> thr)

Hb Chico is an unusual human hemoglobin variant that has lowered oxygen affinity, but unaltered cooperativity and anion sensitivity. Previous studies showed these features to be associated with distal-side heme pocket alterations that confer increased structural rigidity on the molecule and that increase water content in the beta-chain heme pocket. We report here that the extent of nanosecond geminate rebinding of oxygen to the variant and its isolated beta-chains is appreciably decreased. Structural alterations in this variant decrease its oxygen recombination rates without significantly altering rates of migration out of the heme pocket. Data analysis indicates that one or more barriers that impede rebinding of oxygen from docking sites in the heme pocket are increased, with less consequence for CO rebinding. Resonance Raman spectra show no significant alterations in spectral regions sensitive to interactions between the heme iron and the proximal histidine residue, confirming that the functional differences in the variant are due to distal-side heme pocket alterations. These effects are discussed in the context of a schematic representation of heme pocket wells and barriers that could aid the design of novel hemoglobins with altered ligand affinity without loss of the normal allosteric responses that facilitate unloading of oxygen to respiring tissues.     

Morphology and life cycle of a new loriciferan from the Atlantic coast of Florida with an emended diagnosis and life cycle of Nanaloricidae (Loricifera)

Abstract. A new interstitial loriciferan, Nanaloricus gwenae sp. nov., is described from coarse-sand and shell-hash habitats ( Amphioxus sand), at 15–17 m depth, 6–7 miles off the coast of Fort Pierce, FL, USA. The new species is very closely related to the type species Nanaloricus mysticus found off the coast of Roscoff, France in nearly the same kind of sediment ( Dentalium sand). All life stages (Higgins larva, postlarva, and adult) in the life cycle of the new species were found through the 10-year investigation, leading to the conclusion that all species of Nanaloricidae have only a sexual reproductive cycle. The adult of the new species can be distinguished by the different body shape, the lorical spikes and sculpture, and the shape of the scalids. The postlarva has stronger longitudinal ridges on the lorical plates and the Higgins larva has toes with smaller mucrones than those of N. mysticus . An emended definition of the Nanaloricidae is provided based on the new formula of the number of rows and shape of the scalids on the introvert. The associated meiofauna found in the subtidal sand or shell hash is both abundant and diverse. Tardigrades, gastrotrichs, and kinorhynchs are among the most common associates. N . gwenae sp. nov. is represented by only eight specimens collected during a 10-year period of sampling this habitat.     

Loricifera from the deep sea at the Galápagos Spreading Center,with a description of <Emphasis Type="Italic">Spinoloricus turbatio</Emphasis> gen. et sp. nov. (Nanaloricidae)

Specimens of a new species of Loricifera, Spinoloricus turbatio gen. et sp. nov., have been collected at the Galápagos Spreading Center (GSC) during the cruise SO 158, which is a part of the MEGAPRINT project. The new genus is positioned in the family Nanaloricidae together with the three already described genera Nanaloricus, Armorloricus and Phoeniciloricus. The postlarvae and adults of Spinoloricus turbatio gen. et sp. nov. are characterized by a mouth cone with eight oral ridges and basally with a cuticular reinforcement named mouth cone pleat; eighth row with 30 whip-like spinoscalids and 30 “alternating” plates; thorax with eight single and seven double trichoscalids, where the single trichoscalids are twice the length of the double ones, and the secondary appendage on the double trichoscalid is smooth whereas the others are serrated; lorica with eight cuticular plates with additional spikes in the anterior corners and intercalary plicae between the plates. Some of these genus-specific characters such as the mouth cone pleat, the “alternating” plates and the intercalary plicae have not been observed in Nanaloricidae before. The Higgins-larvae of Spinoloricus turbatio gen. et sp. nov. are characterized by six rectangular plates in the seventh row with two teeth, an indistinct honeycomb sculpture and long toes with little mucrones. The SO 158 cruise has yielded a minimum of ten new species of Loricifera out of only 42 specimens. These new species belong to two different orders, where one being new to science, and three different families. This result indicates a high diversity of loriciferans at the GSC. Nearly all the collected loriciferans are in a moulting stage, hence there is a new stage inside the present stage. This prolongation of life stages and the occurrence of multiple life stages inside each other are typical of deep-sea loriciferans. Here exemplified by the two postlarvae with adults inside, which is observed for the first time in Nanaloricidae.     

Indanyl piperazines as melatonergic MT2 selective agents

Optimization of a benzyl piperazine pharmacophore produced N-acyl-4-indanyl-piperazines that bind with high affinity to melatonergic MT(2) receptors. (R)-4-(2,3-dihydro-6-methoxy-1H-inden-1-yl)-N-ethyl-1-piperazine-carboxamide fumarate (13) is a water soluble, selective MT(2) agonist, which produces advances in circadian phase in rats at doses of 1-56 mg/kg that are no different from those of melatonin at 1 mg/kg. Unlike melatonin, 13 produced only weak contractile effects in rat tail artery.     

Dihydropyridine neuropeptide Y Y(1) receptor antagonists

Dihydropyridine 5a was found to be an inhibitor of neuropeptide Y(1) binding in a high throughput (125)I-PYY screening assay. Structure-activity studies around certain portions of the dihydropyridine chemotype identified BMS-193885 (6e) as a potent and selective Y(1) receptor antagonist. In a forskolin-stimulated c-AMP production assay using CHO cells expressing the human Y(1) receptor, 6e demonstrated full functional antagonism (K(b)=4.5 nM). Compound 6e inhibited NPY-induced feeding in satiated rats when dosed at 3.0 and 10.0 mg/kg (ip), and also decreased spontaneous overnight food consumption in rats at doses of 10 and 20 mg/kg (ip).     

The glycosyltransferase repertoire of the spikemoss Selaginella moellendorffii and a comparative study of its cell wall

Spike mosses are among the most basal vascular plants, and one species, Selaginella moellendorffii, was recently selected for full genome sequencing by the Joint Genome Institute (JGI). Glycosyltransferases (GTs) are involved in many aspects of a plant life, including cell wall biosynthesis, protein glycosylation, primary and secondary metabolism. Here, we present a comparative study of the S. moellendorffii genome across 92 GT families and an additional family (DUF266) likely to include GTs. The study encompasses the moss Physcomitrella patens, a non-vascular land plant, while rice and Arabidopsis represent commelinid and non-commelinid seed plants. Analysis of the subset of GT-families particularly relevant to cell wall polysaccharide biosynthesis was complemented by a detailed analysis of S. moellendorffii cell walls. The S. moellendorffii cell wall contains many of the same components as seed plant cell walls, but appears to differ somewhat in its detailed architecture. The S. moellendorffii genome encodes fewer GTs (287 GTs including DUF266s) than the reference genomes. In a few families, notably GT51 and GT78, S. moellendorffii GTs have no higher plant orthologs, but in most families S. moellendorffii GTs have clear orthologies with Arabidopsis and rice. A gene naming convention of GTs is proposed which takes orthologies and GT-family membership into account. The evolutionary significance of apparently modern and ancient traits in S. moellendorffii is discussed, as is its use as a reference organism for functional annotation of GTs.     

A Rad53 Independent Function of Rad9 Becomes Crucial for Genome Maintenance in the Absence of the RecQ Helicase Sgs1

The conserved family of RecQ DNA helicases consists of caretaker tumour suppressors, that defend genome integrity by acting on several pathways of DNA repair that maintain genome stability. In budding yeast, Sgs1 is the sole RecQ helicase and it has been implicated in checkpoint responses, replisome stability and dissolution of double Holliday junctions during homologous recombination. In this study we investigate a possible genetic interaction between SGS1 and RAD9 in the cellular response to methyl methane sulphonate (MMS) induced damage and compare this with the genetic interaction between SGS1 and RAD24. The Rad9 protein, an adaptor for effector kinase activation, plays well-characterized roles in the DNA damage checkpoint response, whereas Rad24 is characterized as a sensor protein also in the DNA damage checkpoint response. Here we unveil novel insights into the cellular response to MMS-induced damage. Specifically, we show a strong synergistic functionality between SGS1 and RAD9 for recovery from MMS induced damage and for suppression of gross chromosomal rearrangements, which is not the case for SGS1 and RAD24. Intriguingly, it is a Rad53 independent function of Rad9, which becomes crucial for genome maintenance in the absence of Sgs1. Despite this, our dissection of the MMS checkpoint response reveals parallel, but unequal pathways for Rad53 activation and highlights significant differences between MMS- and hydroxyurea (HU)-induced checkpoint responses with relation to the requirement of the Sgs1 interacting partner Topoisomerase III (Top3). Thus, whereas earlier studies have documented a Top3-independent role of Sgs1 for an HU-induced checkpoint response, we show here that upon MMS treatment, Sgs1 and Top3 together define a minor but parallel pathway to that of Rad9.