Alpha-crystallins and tumorigenesis.

αA- and αB-crystallins, the major lens structure proteins and members of the small heat-shock proteins (sHSPs) family, play essential roles in maintaining normal cellular structure and physiology of both ocular and some non-ocular tissues. Mutations and abnormal expression of these sHSPs are associated with various human diseases such as cataract, neural disorders, and cardiovascular diseases. In addition, recent studies have revealed that the abnormal expressions and functions of both α-crystallins are associated with several types of tumors. In this regard, αA- and αB-crystallins seem to function differentially or even oppositely during tumorigenesis, and diverse molecular mechanisms have been proposed to explain their roles in cell apoptosis, cell proliferation and tumor metastasis. In this review, we have summarized the current status regarding the expression patterns and functions of αA- and αB-crystallins implicated in tumorigenesis, and discussed the possible mechanisms underlying their functions.

Biodegradation and detoxification of nicotine in tobacco solid waste by a Pseudomonas sp.

A Pseudomonas sp. grew with nicotine optimally 3 g l(-1) and at 30 degrees C and pH 7. Nicotine was fully degraded within 10 h. The resting cells degraded nicotine in tobacco solid waste completely within 6 h in 0.02 m sodium phosphate buffer (pH 7) at maximally 56 mg nicotine h(-1) g dry cell(-1).

Nearly pure blue photoluminescent poly(2,7-[9-)3,5-bis[3,5- bis(benzyloxy)benzyloxy]benzyl)-9-(3,6-dioxaoctyl)]fluorene) in film.

The first unsymmetrically substituted polyfluorene bearing a bulky poly(benzyl ether) dendron and less bulky 3,6-dioxaoctyl groups in the 9-position was designed and synthesized, which gives almost a pure bluish photoluminescence with negligible weak greenish excimer emission around 520 nm even in a thermally annealed thin solid film.

Effects of exogenous triiodothyronine on fast axonal transport during tadpole metamorphosis.

Bullfrog tadpoles at metamorphic stages V, X and XVIII were immersed in 25 nM triiodothyronine (T3) to assess whether the 4-5 fold increase in fast axonal transport (FAxT) previously observed during this span of spontaneous metamorphosis (1) could be mimicked by precocious application of thyroid hormone. The trend initially observed was for T3 to stimulated [35S]methionine incorporation into lumbar DRG and inhibit incorporation in tail DRG. Both effects, however, appeared to be exerted primarily on satellite cells rather than neurons since most of the T3-induced changes in DRG were of a similar magnitude to those in the respective nerve trunks. Findings consistent with this observation resulted from use of the retrogradely transported lectin, ricin120, to determine the proportion of DRG incorporation occurring in neurons. When incorporation of [35S]methionine in lumbar DRG neurons was examined, T3 had no stimulatory effect at any of the metamorphic stages examined. When FAxT was assessed as [35S]protein accumulating proximal to a nerve trunk ligature, and expressed as a percentage of newly-synthesized protein in lumbar DRG neurons, no stimulatory effect of T3 was detected. The question remains whether the changes in FAxT in peripheral neurons observed during spontaneous metamorphosis may be induced by circulating hormones other than T3 or are secondary to changes in the target tissues.

Changes in fast axonal transport in sensory neurons during tadpole metamorphosis.

Fast axonal transport of radiolabeled protein was examined in lumbar and tail dorsal root ganglion (DRG) neurons at progressive stages of bullfrog tadpole metamorphosis. Accumulation of [35S]methionine-labeled protein proximal to a lumbar peripheral nerve ligature (at a fixed distance from the DRG) increased as tadpoles advanced from premetamorphosis through prometamorphosis to metamorphic climax. The rate of increase was steeper when expressed as a percentage of protein synthesized in the neurons of origin than when expressed as a percentage of total DRG protein synthesis. Further, the increase was not secondary to a rise in protein synthesis. In contrast, fast axonal transport decreased in DRG neurons of the tail at the onset of metamorphic climax, when tail resorption is initiated. The stage-related increase in protein transport in lumbar nerves is due, at least in part, to an increased rate of transport. As determined from optically detected anterograde organelles in individual lumbar nerve axons, an approximate doubling of the fast transport rate occurred between the premetamorphic stage and metamorphic climax. In addition, the rates of organelle transport in lumbar axons of adult bullfrogs were significantly greater than in corresponding axons of tadpoles at metamorphic climax, further suggesting that organelle velocity is a developmentally regulated parameter of fast axonal transport.

Selective inhibition of neuronal protein synthesis by retrogradely transported ricin.

The ability of the lectin, ricinus communis agglutinin I (ricin120), to undergo retrograde axonal transport and cause degeneration of neuronal cell bodies has been frequently exploited to establish the origin of peripheral axons. Since this cytotoxic action of ricin results from its inactivation of ribosomes, the retrogradely transported lectin was employed in the present study to inhibit protein synthesis in dorsal root ganglion (DRG) neurons whose axons project into the lumbar nerve trunk of bullfrog tadpoles. The procedure was developed to examine, during tadpole metamorphosis, the ratio of fast-transported radiolabeled protein accumulating at the proximal side of a nerve trunk ligature to the total newly synthesized protein in the cell bodies of origin. The relatively small diameter and fragility of the developing lumbar nerve trunks necessitated introduction of ricin by bath application to the cut nerve end rather than by intraneural injection. Consistent uptake of ricin was achieved by pretreatment with the phospholipase A2 inhibitor, mepacrine, that blocks resealing of severed nerve fibers. Optimal time and dosage of ricin were established by determining the maximal achievable inhibition of [35S]methionine into DRG protein. In stage XVI tadpoles, maximal inhibition of approximately to 65% was observed after 16 h incubation in 2.5 mg/ml ricin. As evidence that neuronal protein synthesis was effectively suppressed, there was no detectable anterograde axonal transport of [35S]protein subsequent to ricin treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

[The changes of monoamine metabolites in CSF of patients with cerebral stroke].

For understanding of the role of monoamines in cerebral ischemia, 3-methoxy-4-hydroxyphenylglycol (MHPG), hydroxyindoleacetic acid (5HIAA) homovanillic acid (HVA) the three major monoamine metabolites in CSF of 33 patients and 18 controls were measured with high-performance liquid chromatography. Results showed MHPG was more sensitive to cerebral ischemia than the two others. All three metabolites were elevated in patients with severe ischemia but only MHPG and 5-HIAA were significantly elevated. A positive correlation between any two of metabolites was found in controls and in patients in the first week after stroke but altered at the end of the second week. Computer assisted multivariate analysis indicated 5-HIAA might contribute more to the state of illness in the acute stage while HVA the least. Clinically, MHPG appeared to be the most significant element on reflecting the degree of the damage and the prognosis of the disease among the metabolites.

Monoamine metabolites in cerebrospinal fluid during and after acute cerebral ischemia.

In order to understand the role of monoamines in cerebral ischemia, 3-methoxy-4-hydroxyphenylglycol(MHPG), 5-hydroxyindoleacetic acid (5-HIAA), and homovanillic acid(HVA), the three major unconjugated monoamine metabolites in cerebrospinal fluid (CSF), of 33 patients and 18 controls were measured with high performance liquid chromatography. Results showed all three metabolites were raised in patients with severe ischemia, but only MHPG and 5-HIAA were elevated significantly, MHPG changes more quickly and regularly as a consequence of cerebral ischemia than the two others. A positive correlation between any pair of metabolites was found in controls and in patients in the first week after stroke, but not at the end of the second week. Computer assisted multivariate analysis indicated 5-HIAA and MHPG correlated more closely with the state of illness in the acute stage, whereas HVA correlated the least. Possible explanations for the changes of CSF levels of amine metabolites are discussed.

Monoamine metabolites in cerebrospinal fluid during acute cerebral ischemia.

To clarify the rule of monoamine in cerebral ischemia, 3-methoxy-4-hydroxyphenylglycol (MHPG), 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA) in cerebrospinal fluid (CSF) of 33 patients and 18 controls were measured with high performance liquid chromatography. Results showed all the three metabolites increased in patients with severe ischemia but only MHPG and 5-HIAA increased significantly. MHPG changed more quickly and regularly in cerebral ischemia than the other two. A positive correlation between any couple of the metabolites was found in both the controls and patients in the first week after stroke, but it was disturbed at the end of the second week. Computer-assisted multivariate analysis indicated that 5-HIAA and MHPG are more closely related to the state of illness in the acute stage while HVA the least. Possible explanations for the changes of CSF levels of amine metabolites were discussed.