Aroma Components of Fresh Sugar Cane Juice

To study the behavior of Bifidobacterium toward oxygen, oxygen uptake was investigated in detail. The cells of Bifidobacterial strains absorbed considerable amounts of oxygen. The exogenous oxygen uptake activity changed depending upon the period of incubation. Bifidobacterial cells also had high endogenous oxygen uptake, which was, in B. longum strains, as high as about 80% of the exogenous oxygen uptake activity. Bifidobacterial cells accumulated considerable amounts of polysaccharide, which was associated with cellular growth. By incubating the cultivated cells in a glucose-free medium, the endogenous oxygen uptake activity was decreased with a decrease of intracellular polysaccharide. Therefore it was postulated that the high endogenous oxygen uptake activity of Bifidobacterium was owing to the metabolism of intracellular polysaccharide. The enzymatic activity, which was involved in the mechanism of oxygen uptake, was also investigated.     

Possible Involvement of Pertussis Toxin Substrates (Gi, Go) in Desipramine-Induced Refractoriness of Adenylate Cyclase in Cerebral Cortices of Rats

To evaluate the efficiency of coupling between beta-receptor and adenylate cyclase catalyst via a GTP-binding protein, Gs, in the brain membrane two parameters were employed: a beta-agonist-induced increase in the membrane GTP-dependent adenylate cyclase activity and a beta-agonist-induced shortening of the lag time preceding the onset of the steady-state activation by guanyl-5'-yl-beta-gamma-imidodiphosphate [Gpp(NH)p] of the membrane cyclase. Both parameters showed lower values in membranes from desipramine-treated rats compared with untreated rats. Thus, coupling of beta-adrenergic receptors to adenylate cyclase in the brain membrane was impaired by the desipramine treatment. Rats once injected intraventricularly with islet-activating protein (IAP), pertussis toxin, were subjected to desipramine treatment, for the purpose of studying effects of another kind of the GTP-binding protein (Gi), which loses its function as a signal transducer on being ADP-ribosylated selectively by the toxin. IAP treatment did not impair the beta-receptor coupling by itself, since neither of the above two parameters for the coupling were reduced by IAP treatment. Moreover, the first parameter was normalized, though the second one was not, by superimposition of the IAP treatment upon the desipramine-treated rats. It seems likely, therefore, that Gi interacts with a Gs-adenylate cyclase coupling in an inhibitory fashion in brain membranes. The desensitization might be overcome when the inhibitory interaction of Gi on the subsequent process is attenuated by IAP treatment.     

Protein engineering of conger eel galectins by tracing of molecular evolution using probable ancestral mutants

Background  

Conger eel galectins, congerin I (ConI) and congerin II (ConII), show the different molecular characteristics resulting from accelerating evolution. We recently reconstructed a probable ancestral form of congerins, Con-anc. It showed properties similar to those of ConII in terms of thermostability and carbohydrate recognition specificity, although it shares a higher sequence similarity with ConI than ConII.     

Synthesis and structure–activity relationships of oxamyl dipeptide caspase inhibitors developed for the treatment of liver disease

The P4 region of a series of oxamyl dipeptide caspase inhibitors was optimized by the combination of anti-apoptotic activity in the Jurkat/Fas (JFas) cellular assay and membrane permeability in the PAMPA assay. Two highly potent anti-apoptotic agents with moderate membrane permeability, 29 and 36, showed strong in vivo efficacy in a murine model of α-Fas-induced liver injury.     

Motor-Coordination-Dependent Learning,More than Others,Is Impaired in Transgenic Mice Expressing Pseudorabies Virus Immediate-Early Protein IE180

The cerebellum in transgenic mice expressing pseudorabies virus immediate-early protein IE180 (TgIE96) was substantially diminished in size, and its histoarchitecture was severely disorganized, resulting in severe ataxia. TgIE96 mice can therefore be used as an experimental model to study the involvement of cerebellar circuits in different learning tasks. The performance of three-month-old TgIE96 mice was studied in various behavioral tests, including associative learning (classical eyeblink conditioning), object recognition, spatial orientation (water maze), startle response and prepulse inhibition, and passive avoidance, and compared with that of wild-type mice. Wild-type and TgIE96 mice presented similar reflexively evoked eyeblinks, and acquired classical conditioned eyelid responses with similar learning curves for both trace and delay conditioning paradigms. The two groups of mice also had similar performances during the object recognition test. However, they showed significant differences for the other three tests included in this study. Although both groups of animals were capable of swimming, TgIE96 mice failed to learn the water maze task during the allowed time. The startle response to a severe tone was similar in both control and TgIE96 mice, but the latter were unable to produce a significant prepulse inhibition. TgIE96 mice also presented evident deficits for the proper accomplishment of a passive avoidance test. These results suggest that the cerebellum is not indispensable for the performance of classical eyeblink conditioning and for object recognition tasks, but seems to be necessary for the proper performance of water maze, prepulse inhibition, and passive avoidance tests.     

Structural requirements for activation in alphaIIb beta3 integrin

Integrins are postulated to undergo structural rearrangement from a low affinity bent conformer to a high affinity extended conformer upon activation. However, some reports have shown that a bent conformer is capable of binding a ligand, whereas another report has shown that integrin extension does not absolutely lead to activation. To clarify whether integrin affinity is indeed regulated by the so-called switchblade-like movement, we have engineered a series of mutant αIIbβ3 integrins that are constrained specifically in either a bent or an extended conformation. These mutant αIIbβ3 integrins were expressed in mammalian cells, and fibrinogen binding to these cells was examined. The bent integrins were created through the introduction of artificial disulfide bridges in the β-head/β-tail interface. Cells expressing bent integrins all failed to bind fibrinogen unless pretreated with DTT to disrupt the disulfide bridges. The extended integrins were created by introducing N-glycosylation sites in amino acid residues located close to the α-genu, where the integrin legs fold backward. Among these mutants, activation was maximized in one integrin with an N-glycosylation site located behind the α-genu. This extension-induced activation was completely blocked when the swing-out of the hybrid domain was prevented. These results suggest that the bent and extended conformers represent low affinity and high affinity conformers, respectively, and that extension-induced activation depends on the swing-out of the hybrid domain. Taken together, these results are consistent with the current hypothesis that integrin affinity is regulated by the switchblade-like movement of the integrin legs.