Raman and infrared spectra of toxin gamma from the venom of the scorpion Tityus serrulatus

Toxin gamma is a basic, low-molecular-weight, neurotoxic protein, isolated from the venom of the Brazilian scorpion, Tityus serrulatus. Raman spectra (400-1800 cm-1 region) of this toxin in both the lyophilized state and in 0.1 M acetate buffer (pH 4.5) and the infrared spectrum (700-4000 cm-1 region) of a solid film were investigated. From the vibrational spectra, it can be concluded that the polypeptide backbone of toxin gamma consists of a mixture of the different secondary structures, with predominance of beta-sheet, followed by unordered structure and alpha-helix, with some evidence of beta-turn structures. The four disulfide bridges assume the gauche-gauche-gauche conformation of the CCSSCC fragments. The intensity ratio of the doublet at 853 and 828 cm-1 suggests that four out of the five tyrosine residues are exposed. The three tryptophan residues are exposed on the surface, and the single methionine residue assume the gauche-gauche conformation. Toxin gamma retains full activity in the pH 4.5-7.5 range, but is almost completely inactivated at pH 11.5.     

Association between light exposure at night and manic symptoms in bipolar disorder: cross-sectional analysis of the APPLE cohort

ABSTRACT

Previous studies have found that keeping the room dark at night was associated with a decrease in manic symptoms for patients with bipolar disorder (BD). However, the association between light at night of real-life conditions and manic symptoms is unclear. We investigated the association between bedroom light exposure at night and manic symptoms in BD patients. One-hundred and eighty-four outpatients with BD participated in this cross-sectional study. The average light intensity at night during sleep was evaluated using a portable photometer for seven consecutive nights. Manic symptoms were assessed using the Young Mania Rating Scale (YMRS), and scores ≥5 were treated as a “hypomanic state.” The median (interquartile range) YMRS score was 2.0 (0–5.0), and 52 (28.2%) participants were in a hypomanic state. The prevalence of a hypomanic state was significantly higher in the participants with an average light intensity at night exposure of ≥3 lux than in those with <3 lux (36.7% versus 21.9%; P = .02). In multivariable logistic regression analysis adjusted for BD type, depressive symptoms, sleep duration, and daytime physical activity, the odds ratio (OR) for a hypomanic state was significantly higher for the participants with an average light intensity at night exposure of ≥3 lux than for those with <3 lux (OR: 2.15, 95% confidence interval: 1.09–4.22, P = .02). This association remained significant at the cutoff value of YMRS score ≥6 (OR: 2.51, 95% confidence interval: 1.15–5.46; P = .02). The findings of this study indicate bedroom light exposure at night is significantly associated with manic symptoms in BD patients. Although the results of this cross-sectional investigation do not necessarily imply causality, they may serve to inform beneficial nonpharmacological intervention and personalized treatment of BD patients.     

β-Amyloid (Aβ) Oligomers Impair Brain-derived Neurotrophic Factor Retrograde Trafficking by Down-regulating Ubiquitin C-terminal Hydrolase,UCH-L1

We previously found that BDNF-dependent retrograde trafficking is impaired in AD transgenic mouse neurons. Utilizing a novel microfluidic culture chamber, we demonstrate that Aβ oligomers compromise BDNF-mediated retrograde transport by impairing endosomal vesicle velocities, resulting in impaired downstream signaling driven by BDNF/TrkB, including ERK5 activation, and CREB-dependent gene regulation. Our data suggest that a key mechanism mediating the deficit involves ubiquitin C-terminal hydrolase L1 (UCH-L1), a deubiquitinating enzyme that functions to regulate cellular ubiquitin. Aβ-induced deficits in BDNF trafficking and signaling are mimicked by LDN (an inhibitor of UCH-L1) and can be reversed by increasing cellular UCH-L1 levels, demonstrated here using a transducible TAT-UCH-L1 strategy. Finally, our data reveal that UCH-L1 mRNA levels are decreased in the hippocampi of AD brains. Taken together, our data implicate that UCH-L1 is important for regulating neurotrophin receptor sorting to signaling endosomes and supporting retrograde transport. Further, our results support the idea that in AD, Aβ may down-regulate UCH-L1 in the AD brain, which in turn impairs BDNF/TrkB-mediated retrograde signaling, compromising synaptic plasticity and neuronal survival.     

Purification of sarcotoxin III, a new antibacterial protein of Sarcophaga peregrina

A glycine-rich antibacterial protein with a molecular mass of 7,000 termed sarcotoxin III, was purified to homogeneity from the hemolymph of third instar larvae of Sarcophaga peregrina. When the hemolymph was fractionated, this protein was recovered in the same fraction as sarcotoxin I, a group of potent antibacterial proteins that have been purified. But, it was clearly different from sarcotoxin I in amino acid composition and molecular mass. Sarcotoxin III was shown to be induced in the hemolymph in response to injury of the larval body wall.     

Regional assignment of the gene for diphtheria toxin sensitivity using subchromosomal fragments in microcell hybrids

Human x mouse microcell hybrids resistant to G418 were constructed between mouse hepatoma cells and human x mouse whole cell hybrids containing only intact human chromosome 5 and 22 with an integrated neo ^r-gene. Among these, microcell hybrid BG15 produced four subclones, BG15-4, BG15-6, BG15-7 and BG15-9, which contained variously sized complements of human chromosome 5. BG15-6 contained an intact human chromosome 5, BG15-7 a deleted human chromosome 5 (5pter-q22) and BG15-4 and BG15-9 a translocation between parts of human chromosome 5 (pter-qter? and pter-q23, respectively) and a mouse chromosome. Southern DNA blot analysis showed that the human dihydrofolate reductase (DHFR) gene was present in all four subclones, whereas the human homolog of the v-fms gene was present in BG15-4 and 15-6, but absent from BG15-7 and 15-9. BG15-4, 15-6 and 15-9 were sensitive to diphtheria toxin, and only BG15-7 was resistant to the toxin. We used these microcell hybrids to restrict further the regional location of the gene for diphtheria toxin sensitivity to the q23 region of human chromosome 5.     

Regional assignment of five genes on human chromosome 19

A human-mouse hybrid segregant HM76Dd40-6 with new characteristics was derived from the hybrid cell line HM76Dd containing human chromosome 19 as the only human chromosome. Three virus sensitivities located on human chromosome 19 (PVS, E11S and RDRC) were lost in HM76Dd40-6, while six other genes (C3, LDLR, EF2, GPI, PEPD and MANB) were retained. Cytogenetic analysis and in situ hybridization using human or mouse repeated sequences as probes showed that the region q13.1-qter of human chromosome 19 had been replaced by a fragment of mouse chromosome. Our results permit further regional assignment for the following five genes on human chromosome 19: GPI in the region cen-q12, MANB in p13.2-q12, E11S and RDRC in q13.1-qter, and EF2 in pter-q12.     

Augmentation of the generation of cell-mediated cytotoxicity in culture by mitomycin C

Summary The effects of mitomycin C (MMC) on the generation of cell-mediated cytotoxicity in primary stimulation culture of human peripheral blood mononuclear cells (PBM) with the B lymphoblastoid Raji cell line were assessed. The cell-mediated cytotoxicity induced in culture was significantly augmented when MMC was added to cultures on day –1 to day 3 for 24 h at concentrations of 2.5×10^–2 g/ml and 2.5×10^–3 g/ml. To identify the cell populations affected by MMC, PBM were separated by adherence to plastic after treatment with MMC for 24 h (day –1). The two populations were recombined with untreated separated cells and stimulated with antigen. The ability to develop an augmented cell-mediated cytotoxicity was associated with the adherent cell fraction of MMC-treated PBM. Therefore, the ability of MMC-treated adherent cells to produce interleukin 1 (IL 1) was examined. Significantly higher levels of IL 1 were produced by treated cells as compared to untreated adherent cells. The results appear to indicate that the selective effects of MMC on the adherent cell fraction, especially the modification of IL 1 production, may be involved in the mechanisms of MMC-induced augmented cell-mediated cytotoxicity.