Mitochondrial Dysfunction in Neurodegenerative Diseases Associated with Copper Imbalance

Copper is an essential transition metal ion for the function of key metabolic enzymes, but its uncontrolled redox reactivity is source of reactive oxygen species. Therefore a network of transporters strictly controls the trafficking of copper in living systems. Deficit, excess, or aberrant coordination of copper are conditions that may be detrimental, especially for neuronal cells, which are particularly sensitive to oxidative stress. Indeed, the genetic disturbances of copper homeostasis, Menkes' and Wilson's diseases, are associated with neurodegeneration. Furthermore, copper interacts with the proteins that are the hallmarks of neurodegenerative disorders, such as Alzheimer's disease, Parkinson's disease, prion diseases, and familial amyotrophic lateral sclerosis. In all cases, copper-mediated oxidative stress is linked to mitochondrial dysfunction, which is a common feature of neurodegeneration. In particular we recently demonstrated that in copper deficiency, mitochondrial function is impaired due to decreased activity of cytochrome c oxidase, leading to production of reactive oxygen species, which in turn triggers mitochondria-mediated apoptotic neurodegeneration.     

Imatinib potentiates antitumor T cell responses in gastrointestinal stromal tumor through the inhibition of Ido

Imatinib mesylate targets mutated KIT oncoproteins in gastrointestinal stromal tumor (GIST) and produces a clinical response in 80% of patients. The mechanism is believed to depend predominantly on the inhibition of KIT-driven signals for tumor-cell survival and proliferation. Using a mouse model of spontaneous GIST, we found that the immune system contributes substantially to the antitumor effects of imatinib. Imatinib therapy activated CD8(+) T cells and induced regulatory T cell (T(reg) cell) apoptosis within the tumor by reducing tumor-cell expression of the immunosuppressive enzyme indoleamine 2,3-dioxygenase (Ido). Concurrent immunotherapy augmented the efficacy of imatinib in mouse GIST. In freshly obtained human GIST specimens, the T cell profile correlated with imatinib sensitivity and IDO expression. Thus, T cells are crucial to the antitumor effects of imatinib in GIST, and concomitant immunotherapy may further improve outcomes in human cancers treated with targeted agents.     

Non-native fish species in Neotropical freshwaters: how did they arrive,and where did they come from?

The invasion of aquatic ecosystems by introduced invasive alien species (IAS) has become a worldwide phenomenon, and often leads to competitive interactions with native species. At high-nutrient levels, native species mostly are outcompeted by the introduced species. We performed an outdoor competition experiment between IAS free-floating Lemna minuta and native Lemna minor in a eutrophicated pond to examine whether the invasive species is the better competitor. We additionally performed an indoor experiment resembling mesotrophic phosphorus (P) conditions to investigate both species’ competitiveness in low P availability and compared with previous experiments at high-nutrient levels. Our results showed that in field conditions, the alien L. minuta was the better competitor. In the mesotrophic indoor condition, however, the native L. minor was the better competitor. Both species produced longer roots in the indoor experiment compared to field conditions. The species’ relative growth rates were also lower in the indoor experiment. A P reduction to mesotrophic condition in the water column thus might reduce invasive L. minuta growth and competitive performance. Additionally, introduction and recovery of L. minor could reduce L. minuta cover, but only following P reduction. Field experiments in mesotrophic ponds are needed to confirm these indoor findings.     

Cloning and endogenous expression of a Eucalyptus grandis UDP-glucose dehydrogenase cDNA

UDP-glucose dehydrogenase (UGDH) catalyzes the oxidation of UDP-glucose (UDP-Glc) to UDP-glucuronate (UDP-GlcA), a key sugar nucleotide involved in the biosynthesis of plant cell wall polysaccharides. A full-length cDNA fragment coding for UGDH was cloned from the cambial region of 6-month-old E. grandis saplings by RT-PCR. The 1443-bp-ORF encodes a protein of 480 amino acids with a predicted molecular weight of 53 kDa. The recombinant protein expressed in Escherichia coli catalyzed the conversion of UDP-Glc to UDP-GlcA, confirming that the cloned cDNA encodes UGDH. The deduced amino acid sequence of the cDNA showed a high degree of identity with UGDH from several plant species. The Southern blot assay indicated that more than one copy of UGDH is present in Eucalyptus. These results were also confirmed by the proteomic analysis of the cambial region of 3- and 22-year-old E. grandis trees by 2-DE and LC-MS/MS, showing that at least two isoforms are present. The cloned gene is mainly expressed in roots, stem and bark of 6-month-old saplings, with a lower expression in leaves. High expression levels were also observed in the cambial region of 3- and 22-year-old trees. The results described in this paper provide a further view of the hemicellulose biosynthesis during wood formation in E. grandis.     

Human Semen Refrigeration at + 4 °C: Bio-kinetic Characteristics

The aim of our study was to evaluate the bio-kinetic characteristics of human semen refrigerated for different periods and to compare the effects of refrigeration at +4 °C against cryopreservation of human sperm at −196 °C. Semen was obtained from 30 male partners of infertile couples (infertile subjects) with the following semen profile: sperm count ≥10 × 10⁶/ml; progressive motility ≥20%; atypical forms <70% and white blood cells <1.0 × 10⁶/ml. Fifteen normospermic subjects were also selected as controls (control subjects). The following tests were carried out on basal, refrigerated and cryopreserved sperm: a) sperm kinetic properties (by Superimposed Image Analysis System); b) the Hypoosmotic Viability Test (HVT) (combined Hypoosmotic Swelling and Viability Test). The results of the study showed that the percentage recovery of kinetic properties and of HVT were optimum for up to 48 h. After refrigeration for 72 h, a drastic decrease in straight motility recovery was observed. No significant differences were observed between cryopreservation and refrigeration at +4 °C for 48 h for motility or HVT recoveries in samples from control subjects. However, in infertile subjects, a significant decrease in straight progressive motility and HVT recoveries was observed in cryopreserved samples compared to those refrigerated for 48 h. Neither refrigeration nor cryopreservation led to the growth of pathogenic bacteria in any of the cases studied. Based on the above results, refrigeration could represent a useful alternative to the cryopreservation method.     

Modulated red blood cell survival by membrane protein clustering

Human and murine blood cells treated with ZnCl₂ and bis(sulfosuccinimidyl)suberate (BS³) (a cross linking agent) undergo band 3 clustering and binding of hemoglobin to red blood cell membrane proteins. These clusters induce autologous IgG binding and complement fixation, thus favouring the phagocytosis of ZnCl₂/BS³ treated cells by macrophages. The extension of red blood cell opsonization can be easily modulated by changing the ZnCl₂ concentration in the 0.1–1.0 mM range thus providing an effective way to affect blood cell recognition by macrophages. In fact, murine erythrocytes treated with increasing ZnCl₂ concentrations have proportionally reduced survivals when reinjected into the animal. Furthermore, the organ sequestration of ZnCl₂/BS³ treated cells strongly resembles the typical distribution of the senescent cells. Since the ZnCl₂/BS³ treatment can also be performed on red blood cells loaded with drugs or other substances, this procedure is an effective drug-targeting system to be used for the delivery of molecules to peritoneal, liver and spleen macrophages.     

Modeling the role of wind and warming on Microcystis aeruginosa blooms in shallow lakes with different trophic status

This study focuses on the role of wind exposure and storm events, in interaction with trophic status and temperature, on the competition between two species: Microcystis aeruginosa and a typical green alga. It is based on a water column model containing ecological and fluid mechanic features including mixing and shear stress at the bottom. This model addresses for the first time the impact of storm events (inducing sediment and nutrient resuspension) on algal dynamics. Simulations with realistic environmental forcings were performed with different sets of wind, temperature, and trophic conditions. With normal temperatures, conditions for dominance and bloom formation of M. aeruginosa in summer are restricted to hypertrophic waters with low wind exposure. Higher wind exposure (above 2 m s^?1) impairs the formation blooms even in favorable trophic conditions and enhances the dominance of green algae. Hotter temperatures allow the dominance of M. aeruginosa for lower phosphorus conditions and higher wind exposure and lead to the exclusion of green algae for high phosphorus content and low wind exposure. Nevertheless, high wind exposure (above 3 m s^?1) still prevents dense bloom formation and allows the coexistence of both species. Storm events bring two counterbalancing features: sediment and nutrient resuspension. The first leads to a decrease of phytoplankton density in response to high turbidity, and the second leads to an increase and better maintenance of M. aeruginosa blooms due to high phosphorus concentration released in the water. This result depends on the timing of the event and on general wind exposure as phosphorus release only benefits M. aeruginosa if exposure to wind is low.     

Noninvasive monitoring of adrenocortical function in captive jaguars (Panthera onca)

Jaguars are threatened with extinction throughout their range. A sustainable captive population can serve as a hedge against extinction, but only if they are healthy and reproduce. Understanding how jaguars respond to stressors may help improve the captive environment and enhance their wellbeing. Thus, our objectives were to: (1) conduct an adrenocorticotrophic hormone (ACTH) challenge to validate a cortisol radioimmunoassay (RIA) for noninvasive monitoring of adrenocortical function in jaguars; (2) investigate the relationship between fecal corticoid (FCM) and androgen metabolite (FAM) concentrations in males during the ACTH challenge; and (3) establish a range of physiological concentrations of FCMs for the proposed protocol. Seven jaguars (3 M, 4 F) received 500 IU/animal of ACTH. Pre‐ and post‐ACTH fecal samples were assayed for corticoid (M and F) and androgen metabolites (M) by RIA. Concentrations of FCMs increased (P80.01) after ACTH injection (pre‐ACTH: 0.90 ± 0.12 µg/g dry feces; post‐ACTH: 2.55 ± 0.25 µg/g). Considering pre‐ and post‐ACTH samples, FCM concentrations were higher (P80.01) in males (2.15 ± 0.20 µg/g) than in females (1.30 ± 0.20 µg/g), but the magnitude of the response to ACTH was comparable (P>0.05) between genders. After ACTH injection, FAMs increased in two (of 3) males; in one male, FCMs and FAMs were positively correlated (0.60; P80.01). Excretion of FCMs was assessed in 16 jaguars (7 M, 9 F) and found to be highly variable (range, 80.11–1.56 µg/g). In conclusion, this study presents a cortisol RIA for monitoring adrenocortical function in jaguars noninvasively. Zoo Biol 31:426–441, 2012. © 2011 Wiley Periodicals, Inc.