Control of the Amount of a 34K Ca2+-Dependent Membrane Binding Protein (Calelectrin)

A 34,000-Da Ca2+-dependent membrane binding protein (34K) was purified from the electric organ of Torpedo marmorata. Specific antibodies to this protein were raised in rabbits, and radioimmunoassay was used to test the presence of 34K in different tissues of Torpedo as well as in other species. In Torpedo, not only the electric organ, but also the muscle, the spleen, and the liver contained 34K antigenicity. Blood was the only tissue in which 34K antigenicity could not be detected. A 34,000-Da protein (Mr 32,000-36,000) that bound to Torpedo acetylcholine receptor (AChR)-rich membrane in a Ca2+-dependent manner and cross-reacted with anti-(Torpedo 34K) antibody was found in chicken muscle, rat muscle, marine mollusk (Aplysia) central ganglia, and rat and human brain. The concentration of 34K seems to be controlled during development. Chicken 34K antigenicity reached a peak on embryonic day 18, declined, and finally gained its maximal value after synaptic maturation. The AChR concentration in chicken legs also changed in the course of muscle development, although it showed a peak on embryonic day 12 and then declined rapidly. In rat diaphragm, both AChRs and 34K were concentrated in the subsynaptic region. Transection of the phrenic nerve induced the synthesis of AChRs in postsynaptic muscle fibers. This operation did not increase the amount of 34K in the diaphragm. On the contrary, it reduced 34K content to the extrasynaptic level. Taken together, these results support the idea that 34K is an important structural constituent of mature synapses, an observation suggesting the involvement of this protein in the function of the mature synapse.     

The bitter iridoids from Viburnum urceolatum

Four new bitter iridoid glucosides, including three bis-iridoids, were isolated from Viburnum urceolatum and their structures elucidated. They are composed of loganin or deoxyloganin as the aglucone esterified with either aromatic glucoside or with glucose in the 4-position.     

Initiation of DNA replication in Escherichia coli

Summary When E. coli F⁺ cells carrying the dna-167 or dnaC2 mutation, which causes the temperature-sensitive initiation of DNA replication, are exposed to a non-permissive temperature to stop the replication of chromosome and F factor, and then transferred back to a permissive temperature with the addition of chloramphenicol, one round of the chromosomal replication occurs, but further replication is inhibited. Under these conditions, F DNA replicates coincidentally with the initiation of the chromosomal replication in both strains. When rifampicin is added to the cells upon lowering of the temperature, the chromosome can not replicate in the F⁺ dna-167 strain, but can do so in the F⁺ dnaC2 strain. F DNA can replicate in both of the mutant strains under these conditions.     

Expression Pattern of Synucleins (Non-Aβ Component of Alzheimer's Disease Amyloid Precursor Protein/α-Synuclein) During Murine Brain Development

Abstract: The non-Aβ component of Alzheimer's disease amyloid precursor protein (NACP) is predominantly a neuron-specific presynaptic protein that may play a central role in neurodegeneration because NACP fragments are found in Alzheimer's disease amyloid and a mutation in the NACP gene is associated with familial Parkinson's disease. In addition, NACP may play an important role during synaptogenesis and CNS development. To understand better the patterns of NACP expression during development, we analyzed the levels of this protein as well as the levels of another synaptic protein (synaptophysin) by ribonuclease protection assay, western blotting, and immunocytochemistry in fetal, juvenile, and adult mouse brain. From embryonic day 12 to 15, there was a slight increase, which was then followed by a more dramatic increase at later time points. Immunocytochemical staining for NACP increases throughout these stages as well. Although NACP appeared early in CNS development, synaptophysin levels started to rise at a later stage. These findings support the contention that NACP might be important for CNS development. Furthermore, the cytosolic component of NACP precedes the particulate component in development, indicating that a redistribution of the protein to the membrane fraction may be important for events later in neuronal development and in synaptogenesis.     

A coumarin acetylglucoside from viburnum suspensum

A new acetylated coumarin glucoside has been isolated from the leaves of Viburnum suspensum and determined as 2′,6′-O-diacetylscopolin on the basis of spectral and chemical evidence.     

Nanogel DDS enables sustained release of IL-12 for tumor immunotherapy

For a valid cytokine immunotherapy of malignancies, a suitable delivery system that ensures slow-release of cytokines is required, because short half-life in vivo of the molecules ruins therapeutic efficacy while causing severe systemic toxic effects. We previously showed that the cholesterol-bearing pullulan (CHP)-based hydrogel nanoparticles, or nanogel, encapsulates, stabilizes and releases various molecules. Here we applied this nanogel to administration in vivo of interleukin-12 (IL-12). Recombinant murine IL-12 (rmIL-12) was successfully incorporated into CHP nanogel simply by incubated with CHP at room temperature. After subcutaneously injected into mice, the CHP/rmIL-12 complex led to a prolonged elevation in IL-12 concentration in the sera. Repetitive administrations of the CHP/rmIL-12, but not rmIL-12 alone, induced drastic growth retardation of preestablished subcutaneous fibrosarcoma without causing any serious toxic event. The present study proposes a novel therapeutic intervention technology, taking advantage of slow and sustained release of bioactive cytokines from the self-assembling biocompatible nanoparticles.     

Involvement of IL-17A in the pathogenesis of DSS-induced colitis in mice

To investigate the etiological implication of IL-17A in inflammatory bowel disease (IBD), dextran sodium sulfate (DSS) was administered to the mice deficient for the IL-17A gene. They showed only faint manifestations of colitis, as revealed by body weight loss, shrinkage in the colon length, serum haptoglobin concentration, and disease activity index. Although the mortality rate of WT mice reached approximately 60%, more than 90% of the IL-17A KO mice survived the DSS treatment. Histological change was also marginal in the IL-17A KO intestine, in which epithelial damage and inflammatory infiltrates were not obvious and the myeloperoxidase activity elevated only slightly. G-CSF and MCP-1 were abundantly produced in WT mouse intestine, whereas the production of these chemokines was drastically hampered in IL-17A-null intestine. The present results show that IL-17A plays a pivotal role in the pathogenesis of DSS-induced colitis, while MCP-1 and G-CSF may be crucially involved in the IL-17A-induced inflammation.