Neuroprotective effect of BDNF in young and aged 6-OHDA treated rat model of Parkinson disease

Brain derived neurotrophic factor (BDNF) has been shown to exert trophic effects on dopaminergic neurons against 6-hydroxydopamine (6-OHDA) in young rat. Since the degeneration of substantia nigra dopaminergic neurons that occurs in Parkinson's disease is more often than not confined to elderly individuals, it is of interest to determine whether the effects of BDNF against 6 hydroxydopamine (6-OHDA) in young rats can be extended to aged animals. 6-hydroxydopamine was stereotaxically injected into the striatum of young (3-months) and aged (24-months) rats, which were treated two hours earlier with BDNF. 6-OHDA results in almost complete destruction of substantia nigra pars compacta dopaminergic neurons. BDNF injection significantly changed apomorphine induced rotations from 132 +/- 15 to 181 +/- 10, staircase test from 73 +/- 2% to 61 +/- 3%, initiation time from 7 +/- 2 to 12 +/- 1 sec, and disengage time from 80 +/- 7 to 90 +/- 5 sec in young and aged animals, respectively. It is concluded that BDNF causes the limited behavior recovery of striatal DA systems from 6-OHDA toxicity in aged animals.     

Impact of protein kinase CK2 on inhibitor of apoptosis proteins in prostate cancer cells

We have previously demonstrated that protein kinase CK2 is a potent suppressor of apoptosis in cells subjected to diverse mediators of apoptosis. The process of apoptosis involves a complex series of molecules localized in various cellular compartments. Among the various proteins that modulate apoptotic activity are inhibitors of apoptosis proteins (IAPs) which are elevated in cancers and have been proposed to block caspase activity. We have examined the impact of CK2 signal on these proteins in prostate cancer cells. Cellular IAPs demonstrate distinct localization and responsiveness to altered CK2 expression or activity in the cytoplasmic and nuclear matrix fractions. Modulation of cellular CK2 by various approaches impacts on cellular IAPs such that inhibition or downregulation of CK2 results in reduction in these proteins. Further, IAPs are also reduced when cells are treated with sub-optimal concentrations of chemical inhibitors of CK2 combined with low or sub-optimal levels of apoptosis-inducing agents (such as etoposide) suggesting that downregulation of CK2 sensitizes cells to induction of apoptosis which may be related to attenuation of IAPs. Decreased IAP protein levels in response to apoptotic agents such as TNFalpha or TRAIL were potently blocked upon forced overexpression of CK2 in cells. Together, our results suggest that one of the modes of CK2-mediated modulation of apoptotic activity is via its impact on cellular IAPs.     

Cowpea Rhizobia Producing Dark Nodules: Use in Competition Studies

During a program of screening rhizobia from West Africa, it was found that some strains produced nodules of unusually dark appearance on cowpeas, but not on peanuts, soybeans, pigeon peas, or mung beans. The dark pigmentation was in the bacteroid zone, was not correlated with nodule effectiveness, and was additional to the leghemoglobin pigment. Only rhizobial strains with a nongummy (“dry”) colony morphology produced dark nodules. Visually distinguishable pink and dark nodules formed on the same root when a mixture of pink and dark strains was applied as inoculum. The dark-nodule phenotype was therefore appraised as a marker and found to be useful for studying nodulation competition with strains of the orthodox pink-nodule type. The competitiveness of 10 pink-nodule strains was examined relative to a black-nodule strain, IRc 256; a range of competitiveness was obtained of less competitive than, equally competitive to, or more competitive than IRc 256. Patterns of primary (early) nodulation were generally the same as patterns of secondary (later) nodulation. Mixed infections by dark and pink strains produced piebald nodules, the frequency of occurrence of which was much greater among primary than among secondary nodules.     

Laser flash photolysis studies of electron transfer between semiquinone and fully reduced free flavins and the cytochrome c-cytochrome oxidase complex

Laser flash photolysis has been used to determine the rate constants for the reduction of bovine cytochrome oxidase and the cytochrome c-cytochrome oxidase complex by the semiquinone and fully reduced forms of various flavin analogues (FH. and FH-, respectively). Under the condition used, the reaction of FH. with free cytochrome oxidase is too slow to compete with FH. disproportionation whereas FH- reacts measurably. Both FH. and FH- are effective in reducing the complex. The reduction of heme a in the complex is shown to proceed via cytochrome c, and a limiting first-order rate is observed in the case of FH- at high complex concentrations. The data indicate that the interaction site for electron transfer to cytochrome c is the same in the complex as with the free protein, and although a tight complex exists, at least small reactants like the flavins are not sterically hindered in their access to the bound cytochrome c. Moreover, the results also establish that intramolecular electron transfer between cytochrome c and cytochrome oxidase within the complex occurs with a first-order rate constant of greater than 700 s-1. Thus, the presence of cytochrome c greatly enhances electron transfer from reduced flavins to cytochrome oxidase.     

Thermostability of Bacillus cereus penicillinase

Williams, Daniel H., III (Hahnemann Medical College, Philadelphia, Pa.), A. Bondi, A. G. Moat, and F. Ahmad. Thermostability of Bacillus cereus penicillinase. J. Bacteriol. 91:257-261. 1966.-The extracellular penicillinase of Bacillus cereus, strain 13-10, exhibited an unusual thermostability. Whereas it was completely and irreversibly inactivated by heating at 70 C, it retained considerable activity when heated at 100 C for 30 min. The active enzyme remaining was completely stable to further heating at temperatures from 40 to 100 C for as long as 1 hr. Preparations of the enzyme heated to 100 C possessed pH (7.0) and temperature (37 C) optima identical with the unheated enzyme. Furthermore, both enzyme preparations exhibited identical combining capacity for the substrate (penicillin G), suggesting that the two preparations had similar hydrolytic properties. Our findings suggest that heating of penicillinase at 100 C results in the formation of a protein complex which is resistant to further denaturation by heat and other agents. Addition of certain metal ions to the enzyme solution before heat treatment increased the stability to heat at 100 C by virtue of their ability to induce complex formation. Pectin was shown to decrease thermostability, presumably by preventing aggregation of proteins present in the enzyme preparations. The well-known stabilizing effect of gelatin may be attributed to its role in enhancing complex formation.     

ELECTRON MICROSCOPIC STUDIES ON THE INDIRECT FLIGHT MUSCLES OFDROSOPHILAMELANOGASTER : II. Differentiation of Myofibrils

The differentiation of the indirect flight muscles was studied in the various pupal stages of Drosophila. Fibrillar material originates in the young basophilic myoblasts in the form of short myofilamants distributed irregularly near the cell membranes. The filaments later become grouped into bundles (fibrils). Certain "Z bodies" appear to be important during this process. The "Z bodies" may possibly be centriolar derivatives and are the precursors of the Z bands. The first formed fibrils (having about 30 thick myofilaments) are already divided into sarcomeres by Z bands. These sarcomeres, however, seem to be shorter than those of the adult fibrils.The H band differentiates in fibrils having about 40 thick myofilaments; the fibrils constrict in the middle of each sarcomere during this process. The individual myofibrils increase from about 0.3 µ to 1.5 µ in diameter during development, apparently by addition of new filaments on the periphery of the fibrils. The ribosomes seem to be the only cytoplasmic inclusions which are closely associated with these growing myofibrils. Disintegration of the plasma membranes limiting individual myoblasts was commonly seen during development of flight muscles, supporting the view that the multinuclear condition of the fibers of these muscles is due to fusion of myoblasts.     

Effect of sitting postures and shoulder position on the cervicocephalic kinesthesia in healthy young males

Information about head orientation, position, and movement with respect to the trunk relies on the visual, vestibular, extensive muscular, and articular proprioceptive system of the neck. Various factors can affect proprioception since it is the function of afferent integration, and tuning of muscular and articular receptors. Pain, muscle fatigue, and joint position have been shown to affect proprioceptive capacity. Thus, it can be speculated that changes in body posture can alter the neck proprioception. This study was undertaken to investigate the effect of body posture on cervicocephalic kinesthetic sense in healthy subjects. Cervicocephalic kinesthetic sensibility was measured by the kinesthetic sensibility test in healthy young adults while in (a) habitual slouched sitting position with arms hanging by the side (SS), (b) habitual slouched sitting position with arms unloaded (supported) (SS-AS), and (c) upright sitting position with arms hanging by the side (US) during maximum and 30 degree right, left rotations, flexion, and extension. Thirty healthy male adults (mean age 27.83; SD 3.41) volunteered for this study. The least mean error was found for the SS-AS position (0.48; SD 0.24), followed by SS (0.60; SD 0.43) and US (0.96; SD 0.71), respectively. For all test conditions, there was significant difference in mean absolute error while head repositioning from maximum and 30 degree rotation during SS and SS-AS positions (p?相似文献   

Characterization of active recombinant 2,3-dihydro-2,3-dihydroxybiphenyl dehydrogenase from Comamonas testosteroni B-356 and sequence of the encoding gene (bphB).

2,3-Dihydro-2,3-dihydroxybiphenyl-2,3-dehydrogenase (B2,3D) catalyzes the second step in the biphenyl degradation pathway. The nucleotide sequence of Comamonas testosteroni B-356 bphB, which encodes B2,3D, was determined. Structural analysis showed that the dehydrogenases involved in the bacterial degradation of aromatic compounds are related to each other and that their phylogenetic relationships are very similar to the relationships observed for dioxygenases that catalyze the initial reaction in the degradation pathway. The bphB sequence was used to produce recombinant active His-tagged B2,3D, which allowed us to describe for the first time some of the main features of a B2,3D. This enzyme requires NAD+, its optimal pH is 9.5, and its native M(r) was found to be 123,000, which makes it a tetramer. These characteristics are very similar to those reported for the related enzyme cis-toluene dihydrodiol dehydrogenase. The Km value and maximum rate of metabolism for 2,3-dihydro-2,3-dihydroxybiphenyl were 73 +/- 16 microM and 46 +/- 4 nmol min-1 microgram-1, respectively. Compared with the cis-toluene dihydrodiol dehydrogenase, B2,3D appeared to be more substrate specific since it was unable to attack cis-1,2-dihydroxy-cyclohexa-3,5-diene.