Variable mutagenic activity of commercial preparations of ABTS (2,2'-azino-di(3-ethyl-benz-thiazoline) sulphonic acid

Different batches of ABTS obtained from the same commercial source varied in their capacity to effect direct mutation in the strains of Salmonella typhimurium used routinely in the incorporation test of Ames. One batch, obtained in 1976, and another obtained early in 1979, both exhibited direct base-pair substitution and frame-shift activities. These activities, however, were absent from each of two batches obtained after 1979, and also from a highly purified preparation from a different source. The possible presence of the unsulphonated immediate precursor of ABTS as a mutagenic impurity is an unlikely explanation for the activity of the mutagenic preparations. It is more probable that the commercial synthesis generated other, mutagenic, impurities which remained in the batches obtained in 1976 and early in 1979, but were absent or were removed from later batches. The identity of these active impurities is unknown. Pure ABTS is neither a direct nor an indirect mutagen.     

From anti-fouling to biofilm inhibition: New cytotoxic secondary metabolites from two Indonesian Agelas sponges

Chemical investigation of Indonesian marine sponges Agelas linnaei and A. nakamurai afforded 24 alkaloid derivatives representing either bromopyrrole or diterpene alkaloids. A. linnaei yielded 16 bromopyrrole alkaloids including 11 new natural products with the latter exhibiting unusual functionalities. The new compounds include the first iodinated tyramine-unit bearing pyrrole alkaloids, agelanesins A–D. These compounds exhibited cytotoxic activity against L5178Y mouse lymphoma cells with IC₅₀ values between 9.25 and 16.76 μM. Further new compounds include taurine acid substituted bromopyrrole alkaloids and a new dibromophakellin derivative. A. nakamurai yielded eight alkaloids among them are three new natural products. The latter include the diterpene alkaloids (?)-agelasine D and its oxime derivative and the new bromopyrrole alkaloid longamide C. (?)-Agelasine D and its oxime derivative exhibited cytotoxicity against L5178Y mouse lymphoma cells (IC₅₀ 4.03 and 12.5 μM, respectively). Furthermore, both agelasine derivatives inhibited settling of larvae of Balanus improvisus in an anti-fouling bioassay and proved to be toxic to the larvae. (?)-Agelasine D inhibited the growth of planktonic forms of biofilm forming bacteria S. epidermidis (MIC < 0.0877 μM) but did not inhibit biofilm formation whereas the oxime derivative showed the opposite activity profile and inhibited only biofilm formation but not bacterial growth. The structures of the isolated secondary metabolites were elucidated based on extensive spectroscopic analysis involving one- and two-dimensional NMR as well as mass spectrometry and comparison with literature data.     

The morphology of the cerebellum the last 25 years.

Advances in our knowledge of the subdivision and the development of the cerebellum during the last 25 years are reviewed. It is concluded that the longitudinal subdivision of the cerebellum has become firmly established in studies of the morphogenesis, the connections and the chemoarchitecture of the cerebellum. A complicated relationship exists between the transverse, lobular subdivision of the cerebellum and the distribution of different mossy fiber systems.     

Composition of Archaea in Seawater,Sediment, and Sponges in the Kepulauan Seribu Reef System,Indonesia

Coral reefs are among the most diverse and productive ecosystems in the world. Most research has, however, focused on eukaryotes such as corals and fishes. Recently, there has been increasing interest in the composition of prokaryotes, particularly those inhabiting corals and sponges, but these have mainly focused on bacteria. There have been very few studies of coral reef Archaea, despite the fact that Archaea have been shown to play crucial roles in nutrient dynamics, including nitrification and methanogenesis, of oligotrophic environments such as coral reefs. Here, we present the first study to assess Archaea in four different coral reef biotopes (seawater, sediment, and two sponge species, Stylissa massa and Xestospongia testudinaria). The archaeal community of both sponge species and sediment was dominated by Crenarchaeota, while the seawater community was dominated by Euryarchaeota. The biotope explained more than 72 % of the variation in archaeal composition. The number of operational taxonomic units (OTUs) was highest in sediment and seawater biotopes and substantially lower in both sponge hosts. No “sponge-specific” archaeal OTUs were found, i.e., OTUs found in both sponge species but absent from nonhost biotopes. Despite both sponge species hosting phylogenetically distinct microbial assemblages, there were only minor differences in Kyoto Encyclopedia of Genes and Genomes (KEGG) functional pathways. In contrast, most functional pathways differed significantly between microbiomes from sponges and nonhost biotopes including all energy metabolic pathways. With the exception of the methane and nitrogen metabolic pathway, all energy metabolic pathways were enriched in sponges when compared to nonhost biotopes.     

Hypertrophy of inferior olivary neurons: a degenerative, regenerative or plasticity phenomenon

After contralateral hemi-cerebellectomy, neurons in the cat inferior olive may either degenerate, appear unchanged (affected) or become hypertrophic. Morphological and physiological aspects of the latter two cell types are studied by means of intracellular recording and injection techniques and compared to normal olivary neurons. It is demonstrated that affected and hypertrophic olivary neurons can be activated by mesodiencephalic stimulation. Affected olivary neurons are morphologically very similar to normal cells. However, they may respond with long latency action potentials only to mesodiencephalic stimulation. Hypertrophic olivary neurons have an enlarged dendritic tree and soma. The soma and proximal dendrites are studded with spine-like processes. Their reaction to mesodiencephalic stimulation is very diverse and may consist of short and/or long latency action potentials that may or may not trigger dendritic spikes. It is argued that olivary hypertrophy does not present either a degenerative or regenerative state, but that both hypertrophic as well as affected olivary neurons can survive axotomy due to a strong and continuous electrotonic coupling, made possible by destruction of the GABAergic cerebellar afferents.     

Hyrtioreticulins A-E, indole alkaloids inhibiting the ubiquitin-activating enzyme, from the marine sponge Hyrtios reticulatus

Hyrtioreticulins A-E (1-5) were isolated from the marine sponge Hyrtios reticulatus, along with a known alkaloid, hyrtioerectine B (6). Structural elucidation on the basis of spectral data showed that 1, 2, and 5 are new tetrahydro-β-carboline alkaloids, while 3 and 4 are new azepinoindole-type alkaloids. Hyrtioreticulins A and B (1 and 2) inhibited ubiquitin-activating enzyme (E1) with IC(50) values of 0.75 and 11μg/mL, respectively, measured by their inhibitory abilities against the formation of an E1-ubiquitin intermediate. So far, only five E1 inhibitors, panapophenanthrine, himeic acid A, largazole, and hyrtioreticulins A and B (1 and 2), have been isolated from natural sources and, among them, 1 is the most potent E1 inhibitor.