Dye coupling and connexin expression by cortical radial glia in the early postnatal subventricular zone

In this study, we have analyzed the specific contribution of the cortical radial glia (RG) for gap junctional communication (GJC) within the postnatal subventricular zone (SVZ). To specifically target RG as source of dye‐coupling in situ, we have developed a new technique that involves direct cell loading through the processes that reach the pial surface, with a mix of gap junction permeant (Lucifer yellow, LY) and nonpermeant (rhodamine‐conjugated dextran 3 KDa, RD) fluorochromes, the latter used as a marker for direct loaded cells. Tissue sections were analyzed for identification of directly loaded (LY+RD+) and coupled cells (LY+RD–) in the SVZ. Directly loaded cells were restricted to the region underlying the pial loading surface area. Coupled cells were distributed in a bistratified manner, along the outer dorsal surface of the SVZ and aligning the ventricle, leaving the SVZ core relatively free. Blocking GJC prior to pial loading greatly reduced dye coupling. Phenotypic analysis indicated that coupling by RG excludes neuroblasts and is mostly restricted to cells of glial lineage. Notwithstanding, no corresponding restriction to specific cell phenotype was found for two connexin isotypes, Cx43 and Cx45, in the postnatal SVZ. The extensive homocellular cell coupling by RG suggests an important role in the regulation of neurogenesis and functional compartmentalization of the postnatal SVZ. © 2012 Wiley Periodicals, Inc. Develop Neurobiol 2012     

ROOT PROFILES AND COMPETITION BETWEEN THE INVASIVE,EXOTIC PERENNIAL,CARPOBROTUS EDULIS,AND TWO NATIVE SHRUB SPECIES IN CALIFORNIA COASTAL SCRUB

The mat-forming succulent, Carpobrotus edulis (Aizoaceae), surrounds and grows over many native plant species in California coastal communities. Two shrub species, Haplopappus ericoides and H. venetus var. sedoides, were found to have shallow root systems that occupied the same soil depths as those of C. edulis. In the presence of C. edulis, the normal rooting profiles of the shrubs were displaced downward, although partial overlap with C. edulis remained. Removal of C. edulis from around individuals of both shrub species resulted in higher predawn xylem pressure potentials in shrubs from the removal treatments as compared to controls, suggesting that the surrounding C. edulis was utilizing water that would otherwise have been available to these shrubs. In H. ericoides, predawn xylem pressure potentials of removal treatment shrubs remained higher than those of the controls throughout the remainder of the dry season even though these shrubs showed a marked increase in canopy area after removal of surrounding C. edulis. Removal of C. edulis from around H. venetus also initially led to higher predawn xylem pressure potentials in the removal shrubs as compared to the controls and increased production of new leaves. After this initial period the predawn xylem pressure potentials of the removal shrubs were not significantly different from those of controls, suggesting that the demand for water by the increased leaf areas eventually matched the enhanced water availability resulting from C. edulis removal. Also, the morphology of H. venetus shrubs changed to that more typical of unaffected individuals. Thus, C. edulis significantly affected not only the water relations of these two shrub species but also their shoot sizes and overall morphologies.     

Efficacy of IFN-λ1 to Protect Human Airway Epithelial Cells against Human Rhinovirus 1B Infection

Impaired interferon (IFN) production has been observed in various obstructive respiratory diseases. This contributes to enhanced sensitivity towards viral infections triggering acute exacerbations. To compensate for this impaired host IFN response, there is need to explore new therapeutic strategies, like exogenous administration of IFNs as prophylactic treatment. In the present study, we examined the protective potential of IFN-λ1 and compared it with the previously established protecting effect of IFN-β. A549 cells and human primary bronchial epithelial cells were first treated with either IFN-β (500 IU/ml) or IFN-λ1 (500 ng/ml) for 18 h. For infection, two approaches were adopted: i) Continuous scenario: after pre-treatment, cells were infected immediately for 24 h with human rhinovirus 1B (HRV1B) in IFN-containing medium, or were cultured for another 72 h in IFN-containing medium, and then infected for 24 h with HRV1B, ii) Pre-treatment scenario: IFN-containing medium was replaced after 18 h and cells were infected for 4 h either immediately after pre-treatment or after additional culturing for 72 h in IFN-free medium. The protective effect was evaluated in terms of reduction in the number of viral copies/infectious progeny, and enhanced expression of IFN-stimulated genes (ISGs). In both cell types and in both approaches, IFN-λ1 and IFN-β treatment resulted in pronounced and long-lasting antiviral effects exemplified by significantly reduced viral copy numbers and diminished infectious progeny. This was associated with strong up-regulation of multiple ISGs. However, in contrast to the IFN-β induced expression of ISGs, which decreased over time, expression of ISGs induced by IFN-λ1 was sustained or even increased over time. Here we demonstrate that the protective potential of IFN-λ1 is comparable to IFN-β. Yet, the long-lasting induction of ISGs by IFN-λ1 and most likely less incitement of side effects due to more localized expression of its receptors could make it an even more promising candidate for prophylactic treatment than IFN-β.     

Elucidating the role of oxidative stress in the therapeutic effect of rutin on experimental acute pancreatitis

Introduction: Acute pancreatitis (AP) may be severe and cause hospitalization or death, and the available treatment is insufficient to control pancreatic inflammation and pain. Rutin is a natural flavonoid with the potential to treat AP via anti-inflammatory, antinociceptive, and antioxidant activities.

Aim: This study investigated the beneficial effects of rutin on experimental AP induced by l-arginine administration in mice.

Methods: The l-arginine-induced AP model was used in Swiss mice (n?=?6–8). Mice submitted to AP induction were treated with rutin (37.5, 75, or 150?mg kg^?1, p.o.) or vehicle (saline) after 24, 36, 48, and 60?h of AP induction. Abdominal hyperalgesia, serum enzymes, interleukin (IL)-6 levels, pancreatic inflammatory parameters, malondialdehyde (MDA) levels, antioxidant enzyme activities, and 3-nitrotyrosine contents were measured 72?h after induction.

Results: Mice submitted to l-arginine injections developed abdominal hyperalgesia and increased serum amylase, lipase, C-reactive protein and IL-6 concentrations; and increased pancreatic myeloperoxidase activity, edema index, MDA, and 3-nitrotyrosine contents. A marked decrease in catalase activity was observed in the pancreas without alterations of superoxide dismutase (SOD) activity compared with the control group. Rutin treatment significantly impaired all the parameters that were altered by AP induction, but increased catalase and SOD activities in the pancreas compared with the vehicle-treated group.

Conclusion: Rutin treatment exerted a protective effect on l-arginine-induced AP by mechanisms involving the reduction of oxidative stress, which suggests that this flavonoid has a potential for future approaches designed for the management of AP.     

The Tim9p-Tim10p complex binds to the transmembrane domains of the ADP/ATP carrier

The soluble Tim9p-Tim10p (Tim, translocase of inner membrane) complex of the mitochondrial intermembrane space mediates the import of the carrier proteins and is a component of the TIM22 import system. The mechanism by which the Tim9p-Tim10p complex assembles and binds the carriers is not well understood, but previous studies have proposed that the conserved cysteine residues in the 'twin CX3C' motif coordinate zinc and potentially generate a zinc-finger-like structure that binds to the matrix loops of the carrier proteins. Here we have purified the native and recombinant Tim9p-Tim10p complex, and show that both complexes resemble each other and consist of three Tim9p and three Tim10p. Results from inductively coupled plasma--mass spectrometry studies failed to detect zinc in the Tim9p-Tim10p complex. Instead, the cysteine residues seemingly formed disulfide linkages. The Tim9p-Tim10p complex bound specifically to the transmembrane domains of the ADP/ATP carrier, but had no affinity for Tim23p, an inner membrane protein that is inserted via the TIM22 complex. The chaperone-like Tim9p-Tim10p complex thus may prevent aggregation of the unfolded carrier proteins in the aqueous intermembrane space.     

Characterization of a Small Family (CAIII) of Microsatellite-Containing Sequences with X-Y Homology

Four X-linked loci showing homology with a previously described Y-linked polymorphic locus (DYS413) were identified and characterized. By fluorescent in situ hybridization (FISH), somatic cell hybrids, and YAC screening, the X-linked members of this small family of sequences (CAIII) all map in Xp22, while the Y members map in Yq11. These loci contribute to the overall similarity of the two genomic regions. All of the CAIII loci contain an internal microsatellite of the (CA)_n type. The microsatellites display extensive length polymorphism in two of the X-linked members as well as in the Y members. In addition, common sequence variants are found in the portions flanking the microsatellites in two of the X-linked members. Our results indicate that, during the evolution of this family, length variation on the Y chromosome was accumulated at a rate not slower than that on the X chromosome. Finally, these sequences represent a model system with which to analyze human populations for similar X- and Y-linked polymorphisms. Received: 29 July 1996 / Accepted: 15 January 1997     

Mammalian polynucleotide phosphorylase is an intermembrane space RNase that maintains mitochondrial homeostasis

We recently identified polynucleotide phosphorylase (PNPase) as a potential binding partner for the TCL1 oncoprotein. Mammalian PNPase exhibits exoribonuclease and poly(A) polymerase activities, and PNPase overexpression inhibits cell growth, induces apoptosis, and stimulates proinflammatory cytokine production. A physiologic connection for these anticancer effects and overexpression is difficult to reconcile with the presumed mitochondrial matrix localization for endogenous PNPase, prompting this study. Here we show that basal and interferon-beta-induced PNPase was efficiently imported into energized mitochondria with coupled processing of the N-terminal targeting sequence. Once imported, PNPase localized to the intermembrane space (IMS) as a peripheral membrane protein in a multimeric complex. Apoptotic stimuli caused PNPase mobilization following cytochrome c release, which supported an IMS localization and provided a potential route for interactions with cytosolic TCL1. Consistent with its IMS localization, PNPase knockdown with RNA interference did not affect mitochondrial RNA levels. However, PNPase reduction impaired mitochondrial electrochemical membrane potential, decreased respiratory chain activity, and was correlated with altered mitochondrial morphology. This resulted in FoF1-ATP synthase instability, impaired ATP generation, lactate accumulation, and AMP kinase phosphorylation with reduced cell proliferation. Combined, the data demonstrate an unexpected IMS localization and a key role for PNPase in maintaining mitochondrial homeostasis.     

Interactions Between Chronic Stress and Chronic Consumption of Caffeine on the Enzymatic Antioxidant System

We studied the effect of chronic caffeine on parameters related to oxidative stress in different brain regions of stressed and non-stressed rats. Wistar rats were divided into three groups: control (receiving water), caffeine 0.3 g/L and caffeine 1.0 g/L (in the drinking water). These groups were subdivided into non-stressed and stressed (repeated restraint stress during 40 days). Lipid peroxide levels and the total radical-trapping potential were assessed, as well as antioxidant enzyme activities superoxide dismutase, gluthatione peroxidase, and catalase in hippocampus, striatum and cerebral cortex. Results showed interactions between stress and caffeine, especially in the cerebral cortex, since caffeine increased the activity of some antioxidant enzymes, but not in stressed animals. We concluded that chronic administration of caffeine led, in some cases, to increased activity of antioxidant enzymes. However, these effects were not observed in the stressed animals.