Exercise during pregnancy mitigates Alzheimer-like pathology in mouse offspring

Physical activity protects brain function in healthy individuals and those with Alzheimer's disease (AD). Evidence for beneficial effects of parental exercise on the health status of their progeny is sparse and limited to nondiseased individuals. Here, we questioned whether maternal running interferes with offspring's AD-like pathology and sought to decipher the underlying mechanisms in TgCRND8 mice. Maternal stimulation was provided by voluntary wheel running vs. standard housing during pregnancy. Following 5 mo of standard housing of transgenic and wild-type offspring, their brains were examined for AD-related pathology and/or plasticity changes. Running during pregnancy reduced β-amyloid (Aβ) plaque burden (-35%, P=0.017) and amyloidogenic APP processing in transgenic offspring and further improved the neurovascular function by orchestrating different Aβ transporters and increasing angiogenesis (+29%, P=0.022). This effect was accompanied by diminished inflammation, as indicated by reduced microgliosis (-20%, P=0.002) and down-regulation of other proinflammatory mediators, and resulted in less oxidative stress, as nitrotyrosine levels declined (-28%, P=0.029). Moreover, plasticity changes (in terms of up-regulation of reelin, synaptophysin, and ARC) were found not only in transgenic but also in wild-type offspring. We conclude that exercise during pregnancy provides long-lasting protection from neurodegeneration and improves brain plasticity in the otherwise unstimulated progeny.     

Effect of PEGylation on the diffusion and stability of chitosan-DNA polyplexes in collagen gels

Diffusion through the extracellular matrix (ECM) is a critical step for the delivery of nanoparticles and genes. Gene delivery requires a carrier that protects the nucleic acid from degradation and facilitates transport. Chitosan is a promising carrier. To increase the circulation time, PEGylation of the carrier is performed. However, the effect of PEGylation on the transport and stability of gene delivery systems in the ECM has only been studied in solutions containing ECM components. We used polymerized collagen and collagen-hyaluronic acid (HA) gels to study the effects of PEGylation on the diffusion and stability of chitosan-DNA polyplexes. We found that PEGylation of the polyplexes was required for diffusion to occur, and PEGylation increased the dissociation between DNA and chitosan to some extent. The presence of HA had a contradictory role: it decreased the penetration depth of PEGylated polyplexes into the gels and increased the diffusion of the polyplexes being mixed into the gels.     

Nr4a1 siRNA expression attenuates α-MSH regulated gene expression in 3T3-L1 adipocytes

Several recent investigations have underscored the growing role of melanocortin signaling in the peripheral regulation of lipid, glucose, and energy homeostasis. In addition, the melanocortins play a critical role in the central control of satiety. These observations, and the latest reports highlighting the emerging role of the nuclear hormone receptor (NR) 4A subgroup in metabolism, have prompted us to investigate the cross talk between [Nle(4), d-Phe(7)] (NDP)-α-MSH and Nr4a signaling in adipose. We have shown that NDP-MSH strikingly and preferentially induces the expression of the NR4A subgroup (but not any other members of the NR superfamily) in differentiated 3T3-L1 adipocytes. Utilization of quantitative PCR on custom-designed metabolic TaqMan low-density arrays identified the concomitant and marked induction of the mRNAs encoding Il-6, Cox2, Pdk4, and Pck-1 after NDP-MSH treatment. Similar experiments demonstrated that the mRNA expression profile induced by cAMP and NDP-MSH treatment displayed unique but also overlapping properties and suggested that melanocortin-mediated induction of gene expression involves cAMP-dependent and -independent signaling. Nr4a1/Nur77 small interfering RNA (siRNA) expression suppressed NDP-MSH-mediated induction of Nr4a1/Nur77 and Nr4a3/Nor-1 (but not Nr4a2/Nurr1). Moreover, expression of the siRNA-attenuated NDP-MSH mediated induction of the mRNAs encoding Il-6, Cox2/Ptgs2, and Pck-1 expression. In addition, Nur77 siRNA expression attenuated NDP-MSH-mediated glucose uptake. In vivo, ip administration of NDP-MSH to C57 BL/6J (male) mice significantly induced the expression of the mRNA encoding Nur77 and increased IL-6, Cox2, Pck1, and Pdk4 mRNA expression in (inguinal) adipose tissue. We conclude that Nur77 expression is necessary for MSH-mediated induction of gene expression in differentiated adipocytes. Furthermore, this study demonstrates cross talk between MSH and Nr4a signaling in adipocytes.     

Salmonella spp. are affected by different levels of water activity in closed microcosms

Controlling water activity (a _w) can significantly impact the growth of Salmonella in poultry litter and manure — a phenomenon that was studied quantitatively using two common serotypes of Salmonella. The quantitative effect of changes in levels of a _w on Salmonella populations was determined using inoculated, frosted glass rectangles placed in closed chambers (microcosms). Glass rectangles with known concentrations of Salmonella enteritidis and S. brandenburg were placed in microcosms maintained at an a _w level of 0.893 for 24 h at room temperature (RT) and then transferred to other microcosms maintained at the same temperature but with higher a _w levels (0.932 and 0.987). Salmonella populations on the slides were quantified at 4, 18, 24, and 48 h. Slightly elevated levels of a _w (<0.1, i.e., 10% equilibrium relative humidity) for 24 h resulted in a 100-fold increase in counts of Salmonella. The data also suggested that in vitro adaptation to dry environments may occur when the organisms are exposed to alternating levels of relatively high and low (0.987 and 0.893) levels of a _w. Any increased tolerance of Salmonella to reduced levels of a _w could be the result of physico-chemical changes in the organism due to selective environmental pressure, formation of a protective biofilm, and/or entry into a dormant state. Results from this study are compatible with those from previously reported on-farm surveys, reinforcing the contention that maintaining a _w below 0.85 in and around litter/manure surfaces in poultry or livestock bedding areas may be a critical factor in safe production of food. Journal of Industrial Microbiology & Biotechnology (2001) 26, 222–225. Received 18 May 2000/ Accepted in revised form 24 January 2001     

Daily and annual variations of free fatty acid, glycerol and leptin plasma concentrations in goats (Capra hircus) under different photoperiods

The aim of the study was to differentiate the impact of lighting conditions and feeding times on the regulation of lipid metabolism of goats under different photoperiods throughout the year. Seven Finnish landrace goats were kept under artificial lighting that simulated the annual changes of photoperiod at 60 degrees N (the longest light period 18 h, the shortest 6 h). Ambient temperature and feeding regime were kept constant. Blood samples were collected six times a year at 2-h intervals for 2 days, first in light/dark (LD) conditions and then after 3 days in constant darkness (DD). Significant daily variations were detected in the concentrations of plasma free fatty acids (FFA) and glycerol throughout the year. The nocturnal decrease and morning rise of FFA levels were related to the photoperiod, while the trough levels of glycerol were associated with the concentrate meal times. In DD conditions, FFA and glycerol rhythms were unstable. A significant seasonal variation was detected in the overall FFA and glycerol levels suggesting decreased lipogenesis in winter, increased lipolysis in spring and high lipogenesis in summer and fall. There was no significant daily rhythm in serum leptin levels, nor did the profiles in LD and DD conditions differ. The leptin level was slightly lower in early fall than in the other seasons, paralleling a small decrease of body mass in the goats after the grazing season. The daily or annual variations of FFA and glycerol levels were not clearly related to leptin concentrations. The results suggest that lipid metabolism of goats is regulated by light even in constant temperature and feeding conditions; however, no significant contribution of leptin levels could be shown.     

Tissue plasminogen activator is a potent activator of PDGF-CC

Tissue plasminogen activator (tPA) is a serine protease involved in the degradation of blood clots through the activation of plasminogen to plasmin. Here we report on the identification of tPA as a specific protease able to activate platelet-derived growth factor C (PDGF-C). The newly identified PDGF-C is secreted as a latent dimeric factor (PDGF-CC) that upon proteolytic removal of the N-terminal CUB domains becomes a PDGF receptor alpha agonist. The CUB domains in PDGF-CC directly interact with tPA, and fibroblasts from tPA-deficient mice fail to activate latent PDGF-CC. We further demonstrate that growth of primary fibroblasts in culture is dependent on a tPA-mediated cleavage of latent PDGF-CC, generating a growth stimulatory loop. Immunohistochemical analysis showed similar expression patterns of PDGF-C and tPA in developing mouse embryos and in tumors, indicating both autocrine and paracrine modes of activation of PDGF receptor-mediated signaling pathways. The identification of tPA as an activator of PDGF signaling establishes a novel role for the protease in normal and pathological tissue growth and maintenance, distinct from its well-known role in plasminogen activation and fibrinolysis.     

The effects of two disulphides on cholinesterase activity in the spectrophotometric assay

1. 5,5'-Dithiobis-(2-nitrobenzoate) did not influence serum cholinesterase activity, whereas 2,2'-dithiodipyridine had an inhibitory effect. 2. The lowering of the molar extinction coefficients observed in the presence of physostigmine may be a result of a reaction between thiolate ions with carbamate moieties. 3. The use of 5,5'-dithiobis-(2-nitrobenzoate) is still recommended in investigations, especially where the quantitative aspects are significant.     

Initial stages in the course of adventitious bud formation on embryos of Picea abies

Adventitious buds on embryos of Picea abies (L.) Karst. developed after a pulse treatment with 250 μ M benzyladenine (BA) of pH 5.5 for 2 h. Light and temperature regimes were not critical during the initial stages. Adventitious buds developed faster after a pulse treatment and the variation among different experiments was lower compared to when the embryos were cultured on media supplemented with BA. Various stages of the differentiation of adventitious buds were identified: stage 1 - appearance of meristematic centres (approximately the first two weeks); stage 2 - development of adventitious bud primordia (approximately the third week); stage 3 - adventitious bud development (from approximately the 4th to the 8th week). This system may be used for further studies on bud differentiation.     

Characterisation of the role of Vrp1 in cell fusion during the development of visceral muscle of <Emphasis Type="Italic">Drosophila melanogaster</Emphasis>

Background  

In Drosophila muscle cell fusion takes place both during the formation of the somatic mesoderm and the visceral mesoderm, giving rise to the skeletal muscles and the gut musculature respectively. The core process of myoblast fusion is believed to be similar for both organs. The actin cytoskeleton regulator Verprolin acts by binding to WASP, which in turn binds to the Arp2/3 complex and thus activates actin polymerization. While Verprolin has been shown to be important for somatic muscle cell fusion, the function of this protein in visceral muscle fusion has not been determined.     

Copper Toxicosis in Bedlington Terriers

Copper toxicosis of Bedlington Terriers (Chronic progressive hepatitis) is a genetically transmitted disease. The typical feature of this disease is accumulation of copper in the liver tissue. The changes vary from mild hepatitis to chronic progressive hepatitis and cirrhosis. The material of this study consists of 2 cases of copper toxicosis examined at the Department of Pathology in Helsinki in the years 1980–82. Moreover a re-examination of tissue samples was made of all Bedlington Terriers examined during the years 1969–1982 at the same department. Six of the 14 examined dogs showed a positive reaction for copper in their liver tissues. The possible relationship of the examined dogs is not yet known.