Autophagy as a protective response to Bnip3-mediated apoptotic signaling in the heart

Bnip3 is a member of the 'BH3-only' Bcl-2 subfamily which has been implicated in apoptotic,(1) necrotic(2) and autophagic cell death.(3,4) We recently reported that Bnip3 is a key mediator of mitochondrial dysfunction and cell death in the ex vivo heart following ischemia/reperfusion (I/R).(5) Moreover, we found that Bnip3 was involved in upregulation of autophagy in I/R and that Bnip3-mediated mitochondrial dysfunction correlated with upregulation of autophagy. Using a model of simulated I/R and overexpression of Bnip3 in HL-1 cardiac myocytes, we determined that Bnip3-mediated upregulation of autophagic activity constituted a protective response against Bnip3 death signaling. Here we present additional evidence that enhanced autophagic activity functions as a cytoprotective pathway to oppose ischemia/reperfusion-related apoptosis.     

Vegetation–Climate Interactions among Native and Invasive Species in Hawaiian Rainforest

We compiled a time series of Earth Observing-1 Hyperion satellite observations with field measurements to compare the structural, biochemical, and physiological characteristics of an invasive nitrogen-fixing tree Myrica faya and native Metrosideros polymorpha in montane rainforests in Hawai’i. Satellite-based canopy water measurements closely tracked variations in leaf area index, and the remotely sensed photochemical and carotenoid reflectance indices (PRI, CRI) indicated variations in upper-canopy leaf chlorophyll and carotenoid content during a climatological transition. The PRI and CRI were related to differences in light-use efficiency of each species, as indicated by field measurements of leaf electron transport rate. The suite of hyperspectral metrics indicated maximum differences in the structure, biochemistry, and physiology of Myrica and Metrosideros when canopy vapor pressure deficit was high during hotter and drier periods. These satellite data, combined with the Carnegue-Ames-Stanford Approach (CASA) carbon cycle model, suggested that Myrica growth rates were 16–44% higher than Metrosideros, with relative differences between species closely linked to climate conditions. The satellite hyperspectral data identified the basic biological mechanisms favoring the spread of an introduced tree, and provided a more detailed understanding of how vegetation–climate interactions affect the time course of plant growth with respect to the invasion process.     

Effects of egg age of Spartocera dentiventris (Berg) (Hemiptera: Coreidae) on parasitism by Gryon gallardoi (Brethes) (Hymenoptera: Scelionidae)

To evaluate the effect of egg age of Spartocera dentiventris (Berg) on the parasitism by Gryon gallardoi (Brethes), groups of 12 eggs of 2, 3, 4, 5, 6, 7, 8, and 12 days old were exposed to one female of G. gallardoi on a test tube, with the wasp observed for 2h subsequently. Later, the eggs were individualised and incubated (25 +/- 1 degrees C; 12h photoperiod) until adult emergence. To identify the preferred age, groups of 12 eggs of 1, 3, 5, 7 and 12 days of age were simultaneously exposed to a parasitoid female on an arena for 2h. These groups were also individualised and incubated until parasitism was confirmed. On all ages tested parasitism was at about 88.5 +/- 2.64%, with a reduction in adult parasitoid emergence with age increasing (P < 0.01). The development time increased with increasing egg age (P < 0.01), with males developing faster. Parasitoid sex ratio for all ages tested was female-biased (0.49:1), with the proportion of males invariant with host age (P > 0.05). When the egg groups were exposed simultaneously, the female preferred eggs one and three days old. The results indicate a preference of G gallardoi for younger eggs of S. dentiventris, with host egg age exerting a negative effect on development time and offspring emergence of the parasitoid.     

An uncleavable uPAR mutant allows dissection of signaling pathways in uPA-dependent cell migration

Urokinase-type plasminogen activator (uPA) binding to uPAR induces migration, adhesion, and proliferation through multiple interactions with G proteins-coupled receptor FPRL1, integrins, or the epidermal growth factor (EGF) receptor (EGFR). At least two forms of uPAR are present on the cell surface: full-length and cleaved uPAR, each specifically interacting with one or more transmembrane proteins. The connection between these interactions and the effects on the signaling pathways activation is not clear. We have exploited an uPAR mutant (hcr, human cleavage resistant) to dissect the pathways involved in uPA-induced cell migration. This mutant is not cleaved by proteases, is glycosylphosphatidylinositol anchored, and binds uPA with a normal K(d). Both wild-type (wt) and hcr-uPAR are able to mediate uPA-induced migration, are constitutively associated with the EGFR, and associate with alpha3beta1 integrin upon uPA binding. However, they engage different pathways in response to uPA. wt-uPAR requires both integrins and FPRL1 to mediate uPA-induced migration, and association of wt-uPAR to alpha3beta1 results in uPAR cleavage and extracellular signal-regulated kinase (ERK) activation. On the contrary, hcr-uPAR does not activate ERK and does not engage FPRL1 or any other G protein-coupled receptor, but it activates an alternative pathway initiated by the formation of a triple complex (uPAR-alpha3beta1-EGFR) and resulting in the autotyrosine phosphorylation of EGFR.     

Cellular and biochemical parameters of exercise-induced oxidative stress: relationship with training levels

To better clarify the relationship between physical activity and oxidative stress, we determined the effects of a maximal test in 18 young subjects with different training levels (six professional Athletes and 12 non-agonists (NA)). Redox homeostasis (total antioxidant activity (TAS), vitamin C and glutathione (GSH)), oxidative damage (diene conjugation and hemolysis), lymphocyte cell death and repair systems (apoptosis, micronuclei and Hsp70 expression) were evaluated. We found that agonistic training led to a chronic oxidative insult (high baseline values of oxidized glutathione (GSSG), micronuclei and hemolysis). On the contrary, NA with the lowest level of training frequency showed a well balanced profile at rest, but they were more susceptible to exercise-induced variations (GSSG/GSH and diene increased values), respect to the NA with an higher level of training. As almost all the parameters employed in this study showed inter-individual variations, the GSSG/GSH ratio remains the most sensitive and reliable marker of oxidative stress, accordingly with other data just reported in the literature.     

2-week triple therapy for Helicobacter pylori infection is better than 1-week in clinical practice: a large prospective single-center randomized study

BACKGROUND: Proton pump inhibitor (PPI)-based triple therapies are considered the standard regimens for Helicobacter pylori eradication, but the optimal duration of these regimens is still controversial. The aim of this study was to compare the efficacy of 1-week versus 2-week triple therapies in H. pylori-positive patients. MATERIALS AND METHODS: A total of 486 consecutive H. pylori-positive patients were randomized to receive omeprazole, 20 mg b.i.d., clarithromycin 500 mg b.i.d., and either amoxicillin 1 g b.i.d. or metronidazole 500 mg b.i.d. for 1 or 2 weeks. Upper gastrointestinal endoscopy and histology were performed at entry and 2 months after the end of therapy. H. pylori status was defined according to histology and urea breath test. RESULTS: At intention-to-treat analysis, 2-week therapy with omeprazole, amoxicillin, and clarithromycin achieved a significantly higher eradication rate than 1- or 2-week regimens with metronidazole (70% versus 52%, p = .003, versus 56%, p < .01) and the same therapy for 1-week (70% versus 57%, p = .05). At per-protocol analysis, 2-week therapy with omeprazole, amoxicillin, and clarithromycin showed a significantly higher eradication rate than 1-week of amoxicillin and metronidazole (77% versus 62%; p = .03) but no difference with 1-week same regimen (66%) or 2-week metronidazole and clarithromycin regimen (72%). Compliance and tolerability were good for all regimens. CONCLUSIONS: Two-week therapies, independently of antibiotic combination, lead to a significant increase of H. pylori eradication rate compared to 1-week therapies, with same compliance and tolerability, even if, taking account of low-eradication rates, one must question whether the triple therapy should still be used.     

Issues to consider for preparing ferrets as research subjects in the laboratory

The domestic or European ferret (Mustela putorius furo) has been domesticated for thousands of years. Ferrets have been used for hunting and fur production, as pets, and as models in biomedical research. Despite the relatively small numbers used in the laboratory, ferrets have some unique applications including study of human influenza and severe acute respiratory syndrome (SARS)-associated corona virus. They have served as models for peptic ulcer disease, carotenoid metabolism, cystic fibrosis, and drug emesis screening, among others. Most research ferrets are males, due to estrus-related health problems in females. They may be housed conventionally and are easy to care for when their biology and behavior are understood. Due to the small number of ferret suppliers, animals are often shipped long distances, requiring air transport and intermediate handlers. It is important to minimize shipment stress, especially with weanling and pregnant animals. Additional expertise is required for success with pregnant and whelping ferrets and for rearing of neonates. The animals have specific dietary requirements, and proper nutrition is key. Successful housing requires knowledge of ferret behaviors including social behavior, eating habits, a general inquisitive nature, and a species-typical need to burrow and hide. Regular handling is necessary to maintain well-being. A ferret health care program consists of physical examination, immunization, clinical pathology, and a working knowledge of common ferret diseases. Various research methodologies have been described, from basic procedures such as blood collection to major invasive survival surgery. Ferrets have a distinct niche in biomedical research and are hardy animals that thrive well in the laboratory.     

Antibiotic production improvement in the rare actinomycete Planobispora rosea by selection of mutants resistant to the Aminoglycosides Streptomycin and Gentamycin and to Rifamycin

During a strain improvement program, spontaneous mutants with single or combined resistance to streptomycin (Str^r), gentamycin (Gen^r) or rifamycin (Rif^r) were selected from the industrial strain of Planobispora rosea, which is the producer of thiazolylpeptide GE2270. Among the mutants resistant to each single antibiotic, higher producers occurred more frequently (60%) among Gen^r than in Rif^r (10%) and Str^r (24%) populations. Two Gen^r mutants showed up to 1.5-fold improvement in GE2270 production while single resistant mutants Str^r and Rif^r produced slightly more than the parental strains. The combination of Str^r and Rif^r in the same strain improved GE2270 yield up to 1.7-fold. Finally, a higher GE2270 producing strain (1.8-fold improvement with respect to the parental strain) was selected among those mutants with triple resistance to streptomycin, rifamycin and gentamycin. A hierarchical increase in aerial mycelium and spore formation was observed which paralleled GE2270 production improvement.     

Apoptosis and atrophy in rat slow skeletal muscles in chronic heart failure

Congestive heart failure is characterized by a skeletal musclemyopathy with muscle bulk loss. The mechanisms responsible for thesechanges are not clear at present. We have investigated the role ofapoptosis in the rat "slow" soleus muscle during the developmentof heart failure, which was induced by injection of monocrotaline (30 mg/kg). We looked at the time course of apoptosis by studying sixanimals at each of the following time points: 0, 17, 24, and 30 days.We found a decreased expression of the antiapoptotic protein Bcl-2,which was accompanied by a rise of proapoptotic caspase-3. Ubiquitinlevels did not change. DNA nick-end labeling showed an increased numberof apoptotic nuclei both in myofibers and interstitial cells when heartfailure occurred. At variance with previous observations in thefast-twitch tibialis anterior muscle in the same animals, in whichtumor necrosis factor- (TNF-) increased at the time thatapoptosis occurred, the magnitude of apoptosis is lower in soleusmuscle and there is no appearance of muscle atrophy. In soleus muscle,apoptosis is accompanied by activation of the caspase-3 system. Thereis no activation of the TNF-- and ubiquitin-dependent protein waste.In conclusion, slow muscles are less prone to develop apoptosis thanfast muscles. Muscle atrophy appears earlier in these latter ones.