Non-canonical amino acid labeling in vivo to visualize and affinity purify newly synthesized proteins in larval zebrafish

Protein expression in the nervous system undergoes regulated changes in response to changes in behavioral states, in particular long-term memory formation. Recently, methods have been developed (BONCAT and FUNCAT), which introduce non-canonical amino acids bearing small bio-orthogonal functional groups into proteins using the cells' own translational machinery. Using the selective 'click reaction', this allows for the identification and visualization of newly synthesized proteins in vitro. Here we demonstrate that non-canonical amino acid labeling can be achieved in vivo in an intact organism capable of simple learning behavior, the larval zebrafish. We show that azidohomoalanine is metabolically incorporated into newly synthesized proteins, in a time- and concentration-dependent manner, but has no apparent toxic effect and does not influence simple behaviors such as spontaneous swimming and escape responses. This enables fluorescent labeling of newly synthesized proteins in whole mount larval zebrafish. Furthermore, stimulation with a GABA antagonist that elicits seizures in the larval zebrafish causes an increase in protein synthesis throughout the proteome, which can also be visualized in intact larvae.     

The recurrence interval of forest fires in Cabeço da Vaca (Cabreira Mountain—northwest of Portugal)

The recurrence of forest fires is degrading an important part of the Portuguese natural heritage namely its forest and soils.In this paper we present the case study of Cabeço da Vaca (Cabreira Mountain—northwest Portugal), where in recent decades, particularly in the 70s, there was a significant increase in the number of forest fires and in the areas scorched annually. There is thus a turning point between a period when fire was an integral part of the ecosystems and when fire has become a serious threat to woodland management and development (Bento Gonçalves, 2006).Starting with a thorough characterization of forest fires and based on the mapping of scorched areas between 1990 and 2006, we have proceeded to identify the annual pattern of maximum recurrence and the definition of the return interval in Cabeço da Vaca, producing thus a valuable document to support management and forestry development in general.     

The prognostic significance of beta(2)-microglobulin in patients with Hodgkin's lymphoma

BACKGROUND AND OBJECTIVES: Serum beta(2)-microglobulin (s beta(2)m) is an established prognostic factor for multiple myeloma and non-Hodgkin's lymphoma, but only limited data suggest an adverse prognostic significance for Hodgkin's lymphoma (HL). This study was undertaken to examine the impact of s beta(2)m on the prognosis of patients with HL. DESIGN AND METHODS: s beta(2)m was measured by a radioimmunoassay (upper normal limit 2.4 mg/L), in pretreatment serum samples of 232 patients with HL, who were then treated with ABVD or equivalent regimens with or without radiotherapy. Multivariate survival analysis was based on Cox's proportional hazards model. RESULTS: Main patients' characteristics: median age 30.5 years (14-78); 58% males; 68% nodular sclerosis, 20% mixed cellularity and 12% lymphocyte predominance; 34% B-symptoms; 24% Ann Arbor stage I, 49% II, 18% III and 9% IV. Elevated s beta(2)m levels were detected in 65/232 patients (28%) and correlated with older age (p<0.001), mixed cellularity (p=0.03), B-symptoms (p=0.002), advanced stage (p=0.02), > or = 5 involved sites (p=0.02), inguinal/iliac involvement (p=0.009), lymphocytopenia (p=0.002) and elevated lactate dehydrogenase (p=0.01). The 7-year failure free survival (FFS) was 75% vs. 72% for patients with normal vs. elevated s beta(2)m (p=0.15). The corresponding 7-year overall survival (OS) rates were 86% vs. 52% (p=0.003). In multivariate analysis, elevated s beta(2)m was not predictive of FFS, but was independently associated with inferior OS (p=0.01), along with the number of involved sites (p<0.001). INTERPRETATION AND CONCLUSIONS: s beta(2)m is not a potent prognostic factor for FFS in optimally treated patients with HL. However s beta(2)m may be predictive of OS, probably due to its effect on the timing of treatment failure.     

Lead induced oxidative damage and its response to combined administration of alpha-lipoic acid and succimers in rats

Alpha-lipoic acid (LA) has been reported to be highly effective in improving the thiol capacity of the cells and in reducing lead induced oxidative stress. These results suggested its possible role as a therapeutic intervention of lead poisoning in combination with a chelator. We investigated the effects of LA, either alone or when administered in combination with succimer (meso 2,3-dimercaptosuccinic acid; DMSA or one of its analogue monoisoamyl DMSA), in influencing the lead induced alterations in haem synthesis pathway, hepatic, renal and brain oxidative stress and lead concentration from blood and soft tissues. The results suggest a significant lead induced inhibition of delta-aminolevulinic acid dehydratase (ALAD), reduction in glutathione (GSH) and an increased zinc protoporphyrin (ZPP) level in blood, indicating altered heme synthesis pathway. Both the thiol chelators were able to increase blood ALAD activity and GSH level towards normal. The most prominent effect on blood ALAD activity was however observed when monoisoamyl DMSA (MiADMSA) was co-administered with LA. Lead exposure produced significant depletion of hepatic GSH, while, oxidized glutahione (GSSG), thiobarbituric acid reactive substances (TBARS) and catalase activity increased significantly, suggesting hepatic oxidative stress. All the treatments were able to increase hepatic GSH and reduce GSSG levels, while, TBARS level reduced significantly in animals administered LA and MiADMSA, individually or in combination. Lead induced increase in renal GSSG, TBARS levels and catalase activity, were effectively reduced by LA, while, the two chelators when administered alone were effective only in reducing GSSG and catalase activity. The most prominent beneficial effects, however, were observed in animals treated concomitantly with LA and one of the chelators (DMSA or MiADMSA). Brain GSH and GSSG levels decreased moderately while superoxide dismutase (SOD) activity remained statistically unaltered on lead exposure. Brain catalase activity, on the other hand, increased significantly. Administration of LA was effective in reducing these alterations in the brain, however, the best effects were achieved in animals co-administered LA and one of the thiol chelators. The results point to a significant beneficial role of LA in the recovery of altered biochemical variables both during monotherapy and when given in combination with succimer. It however, showed no chelating properties in decreasing lead burden from blood, liver and kidneys except for a significantly more pronounced decrease in brain lead concentration in animals administered LA plus thiol chelators, compared to the effects of chelating agents alone. This is an interesting and notable observation, which requires further exploration. The results thus provide evidence of an encouraging role of LA when given in combination with a thiol chelator in the therapeutic intervention of lead poisoning, particularly in reducing the oxidative stress and brain lead concentration.     

Treatment of experimentally induced transient cerebral ischemia with low energy laser inhibits nitric oxide synthase activity and up-regulates the expression of transforming growth factor-beta 1

BACKGROUND AND OBJECTIVES: Nitric oxide (NO) has been shown to be neurotoxic while transforming growth factor-beta 1 (TGF-beta1) is neuroprotective in the stroke model. The present study investigates the effects of low energy laser on nitric oxide synthase (NOS) and TGF-beta1 activities after cerebral ischemia and reperfusion injury. STUDY DESIGN/MATERIALS AND METHODS: Cerebral ischemia was induced for 1 hour in male adult Sprague-Dawley (S.D.) rats with unilateral occlusion of middle cerebral artery (MCAO). Low energy laser irradiation was then applied to the cerebrum at different durations (1, 5, or 10 minutes). The activity of NOS and the expression of TGF-beta1 were evaluated in groups with different durations of laser irradiation. RESULTS: After ischemia, the activity of NOS was gradually increased from day 3, became significantly higher from day 4 to 6 (P < 0.001), but returned to the normal level after day 7. The activity and expression of the three isoforms of NOS were significantly suppressed (P < 0.001) to different extents after laser irradiation. In addition, laser irradiation was shown to trigger the expression of TGF-beta1 (P < 0.001). CONCLUSIONS: Low energy laser could suppress the activity of NOS and up-regulate the expression of TGF-beta1 after stroke in rats.