Altered glucose metabolism and its association with carbonic anhydrase 8 in Machado-Joseph Disease.

Machado-Joseph disease (MJD), also known as spinocerebellar ataxia type 3 (SCA3), is an autosomal dominant neurodegenerative disease. This disorder is caused by polyglutamine (polyQ)-containing mutant ataxin-3, which tends to misfold and aggregate in neuron cells. We previously demonstrated a protective function of carbonic anhydrase 8 (CA8) in MJD disease models and a decreased glycolytic activity associated with down-regulated CA8 in a human osteosarcoma (OS) cell model. Given that a reduction in body weight accompanied by gait and balance instability was observed in MJD patients and transgenic (Tg) mice, in this study, we aimed to examine whether metabolic defects are associated with MJD and whether CA8 expression is involved in metabolic dysfunction in MJD. Our data first showed that glucose uptake ability decreases in cells harboring mutant ataxin-3, but increases in cells overexpressing CA8. In addition, the expressions of glucose transporter 3 (GLUT3) and phosphofructokinase-1 (PFK1) were significantly decreased in the presence of mutant ataxin-3. Consistently, immunohistochemistry (IHC) showed that GLUT3 was less expressed in cerebella of aged MJD Tg mice, indicating that the dysfunction of GLUT3 may be associated with late-stage disease. On the other hand, transient down-regulation of CA8 revealed decreased expressions of GLUT3 and PFK1 in HEK293 cells harboring wild-type (WT) ataxin-3, but no further reduction of GLUT3 and PFK1 expressions were observed in HEK293 cells harboring mutant ataxin-3. Moreover, immunoprecipitation (IP) and immunofluorescence (IF) demonstrated that interactions exist between ataxin-3, CA8 and GLUT3 in MJD cellular and Tg models. These lines of evidence suggest that CA8 plays an important role in glucose metabolism and has different impacts on cells with or without mutant ataxin-3. Interestingly, the decreased relative abundance of Firmicutes/Bacteroidetes (F/B) ratio in the feces of aged MJD Tg mice coincided with weight loss and metabolic dysfunction in MJD. Taken together, our results are the first to demonstrate the effects of CA8 on glucose metabolism and its involvement in the metabolic defects in MJD disease. Further investigations will be required to clarify the underlying mechanisms for the metabolic defects associated with MJD.

ZnO nanorod optical disk photocatalytic reactor for photodegradation of methyl orange.

A low-cost and efficient photocatalytic reactor for environmental treatment and green technology was presented. ZnO nanorods firmly growing on polycarbonate optical disk substrate are generally perpendicular to the substrate as the immobilized photocatalyst of the spinning disk reactor. The photocatalytic efficiency and durability of the ZnO nanorods are effectively demonstrated.

Alternating oligo[(2,3-O-isopropylidene-L-threitol)]-co-[(E,E)-1,4-bis(styryl)benzene]s: the linear chirality transmission additivity relationship in nematic liquid crystals.

Alternating oligo[2,3-O-isopropylidene-L-threitol]-co-[(E,E)-1,4-bis(styryl)benzene]s (denoted as 2-6 in the article) show helical twisting power (HTP), in 4-pentoxyl-4'-biphenylcarbonitrile (5OCB), linearly proportional to the number of the chiral cores in the oligomers. The HTP per chiral core of -1.75 microm(-1) was recorded in the correlation plot with a correlation coefficient of R = 0.99. These results suggested that the C(2) chiral L-threitol cores are aligned along the same axis. The comparable linear dichroism (LD) of 0.42 +/- 0.02 obtained for (rac)-2-5 at 405 nm, and of 0.52 +/- 0.03 for E7, a commercially available room temperature nematic solvent, at 347 nm in a parallel rubbed cell indicated that the long axis of the bis(styryl)benzene segments is more or less parallel to the director of the E7 in the LC matrix. This observation is highly exciting because the HTP per core could still be maintained, no matter whether the cores are evenly spread in a form of monomer in the LC matrix or tightly confined in a polymer. Theoretical treatments about the conformations of the dopant in the nematic matrix are discussed.

Direct measurements of intersystem crossing rates and triplet decays of luminescent conjugated oligomers in solutions.

Photothermal calorimetry and fluorescence spectroscopy were used to determine the relaxations of the photoexcited singlet state of two PPV and polyfluorene oligomers, (E,E)-1,4-bis[(2-benzyloxy)styryl]benzene (PVDOP) and ter(9,9'-spirobifluorene) (TSBF). The decay rates of different S1 relaxation channels, which include intersystem crossing (ISC), radiative, and nonradiative decay can be determined by the combination of photoacoustic calorimetry (PAC) and the time-correlated single photon counting (TCSPC) technique. The triplet state energy level is determined by the phosphorescence (Ph) spectra recorded at 77 K. The ISC yields are approximately 3% and 6% for PVDOP and TSBF, respectively. The T1 to S0 transition decay rate is acquired by PAC and photothermal beam deflection (PBD) measurements. The triplet state decay rate is 17 and 21 ms(-1) at room temperature. The Ph intensity decay at 77 K shows that the triplet state lifetime increases by 4 orders of magnitude, as compared to room temperature.