Acyclo C-Nucleoside Analogs. Regioselective Annellation of a Triazole Ring to 5-Methyl-1,2,4-Triazino[5,6-b]Indole and Formation of Certain 3-Poly Hydroxyalkyl Derivatives

ABSTRACT

Cyclodehydrogenation of the ethylidene derivative of (5-methyl-1,2,4-triazino[5,6-b]indol-3-yl)hydrazine (1) gave the angular isomer, 1,10-dimethyl-1,2,4-triazolo[3′,4′:3,4][1,2,4]triazino[5,6-b]indole (4). The linear isomer, 3,10-dimethyl-1,2,4-triazolo[4′,3′:2,3][1,2,4]triazino[5,6-b]indole (7) could be prepared regioselectively by the cyclodehydration of the acetyl derivative of 1. The cyclodehydrogenation was extended to the monosaccharide derivatives of 1. The role of the N-methyl group on the site of annellation has been discussed.     

Late Pleistocene gastropods from the raised reefal limestone of Jeddah,Saudi Arabia: taxonomic and palaeoenvironmental implications

A temporarily exposed 6-m succession of raised reefal limestone terrace south of Sharm Obhur (Jeddah) was investigated with regard to macrofossil gastropods and their palaeoenvironmental implications. The studied succession consists of two distinct layers. The lower layer consists of white limestone (4 m thick) of Late Pleistocene age, while the upper layer consists of shell-rich calcareous clay (2 m thick) and belongs to the last interglacial marine isotope stage 5e (MIS 5e). Its lithology was correlated with a nearby temporarily exposed 3-m succession, indicating that the deposition of the MIS 5e was not continuous, as indicated by the occurrence of a 0.4-m-thick weathered layer between the lower white limestone and upper calcareous clay. The studied 6-m succession yielded a very rich gastropod fauna with 90 species belonging to 4 subclasses, 5 orders, 16 superfamilies, 33 families and 64 genera. The clayey layer showed higher species richness (65 species) than the limestone layer (18 species), indicating a rapid change in the coral reef environment during the deposition of the interval of MIS 5e. It is assumed that, after the weathering interval, the sea level could not rebound to the same level as it was during the deposition of the white limestone, leading to deposition of calcareous clay in a shallow platform or embayment, allowing proliferation of gastropod species. Littorinimorpha and Neogastropoda species represent about 75% of the total recorded gastropod taxa, whereas Vetigastropoda and Caenogastropoda represent only 25% of the total recorded taxa. Superfamilies Cerithioidea and Stromboidea dominated the clay layer, whereas no particular species dominated the limestone layer.     

Correction to: Out‑of‑field effects: lessons learned from partial body exposure

Radiation and Environmental Biophysics -     

Kinesins in the Arabidopsis genome: A comparative analysis among eukaryotes

Background  

Receptor protein tyrosine phosphatase rho (RPTPρ, gene symbol PTPRT) is a member of the type IIB RPTP family. These transmembrane molecules have been linked to signal transduction, cell adhesion and neurite extension. The extracellular segment contains MAM, Ig-like and fibronectin type III domains, and the intracellular segment contains two phosphatase domains. The human RPTPρ gene is located on chromosome 20q12-13.1, and the mouse gene is located on a syntenic region of chromosome 2. RPTPρ expression is restricted to the central nervous system.     

Survivorship,potential, and realized fecundity ofBiosteres tryoni [Hymenoptera: Braconidae], a larval parasitoid ofCeratitis capitata [Diptera: Tephritidae]

Laboratory-rearedBiosteres tryoni (Cameron) reached peak ovarian maturation on the 5^th and 7^th days after emergence in unmated and mated ♀♀, respectively. When ♀♀ were not allowed to oviposit, contents of the oocytes were hydrolyzed and reabsorbed. However, when hosts were available for oviposition a significant increase of egg maturation rate was noticed. Mean realized fecundity during the life span was 71.7±8.1 and 69.0±6.7, and mean longevity was 13.5±0.9 and 15.1±0.6 days for mated and unmated ♀♀ respectively.