Influence of Diet on Visceral Adipose Remodeling in NONcNZO10 Mice With Polygenic Susceptibility for Type 2 Diabetes

Visceral adipose tissue (VAT) is a source of inflammatory cytokines that in obese subjects may contribute to low‐level systemic inflammation and development of metabolic syndrome. Expansion of VAT involves adipocyte hyperplasia and hypertrophy and requires breakdown of the extracellular matrix and increased vascular outgrowth. To investigate changes of gene expression associated with VAT expansion and the role of combined genetics and diet, we implemented gene microarray analyses of VAT in NONcNZO10 (NZ10) and control SWR/J mice subjected to control chow (CD) or a diet of high protein and fish oil (HPO). NZ10 mice on CD showed increased body weight, hyperglycemia, and hyperinsulinemia at 25 weeks whereas those on HPO diet retained normal insulin levels and were normoglycemic. Two‐way ANOVA revealed a significant interaction between diet and strain on blood glucose, serum insulin, and percent fat but not for body weight. Microarray heat maps revealed a remarkable combined effect of genetics and diet on genes that regulate extracellular matrix as well as angiogenic genes. Real time‐PCR (RT‐PCR) confirmed markedly increased expression of matrix metalloproteinases (MMPs) 2, 3, 11, and 12, vascular endothelial growth factor‐A and C (VEGF‐A and C), Von Willebrand Factor, and peroxisome proliferator‐activated receptor‐γ (PPAR‐γ) selectively in the NZ10/CD group. MMP7 was significantly decreased. Protein levels of MMP2, 3, and 9 were significantly increased in the VA of NZ10 mice fed CD while those of MMP7 were downregulated. Microarrays also revealed diet‐dependent two to fourfold increased expression of all four tissue inhibitor of metalloproteinases (TIMP) isoforms in NZ10 mice. Two‐way ANOVA confirmed strongly interactive roles of diet and genetics on fat deposition and progression of type 2 diabetes in this polygenic mouse model.     

On the way to overcome some ecological riddles of forested headwaters

Life cycles of many detritivores are synchronized to the autumnal input of leaf material in temperate forested headwaters, though some conditions that occur at this season does not seem the most appropriate for an optimal development and growth of individuals. We hypothesized that spring–summer conditions characterized by high temperature and low discharge would support larger numbers of invertebrate individuals inhabiting leaf packs, mostly shredders, and thus larger productivity values. We estimated the production of a dominant detritivore, the chironomid Brillia bifida (Kieffer, 1909), on habitats that represent their specific resource (i.e., leaf packs with different quality) on a seasonal basis that accounted for the high variability of these ecosystems. Our results showed that shredders dominated in numbers (45.8%) during late spring, with B. bifida individuals representing up to 91.7%, mostly on deciduous leaves such as alder, although the individual body size was higher in autumn–winter than in late spring. A laboratory experiment was conducted to complement our field results, and to test only the effects of water temperature and food quality on the development and growth of B. bifida. Our laboratory experiment confirmed the importance of temperature and food quality as main controls on growth–developmental parameters. These controls could strongly affect the ecological strategy of reproduction and colonization of this key detritivore, and ultimately its secondary production.     

Phospholipase D2: a pivotal player modulating RBL-2H3 mast cell structure

The current study examined the role of PLD2 in the maintenance of mast cell structure. Phospholipase D (PLD) catalyzes hydrolysis of phosphatidylcholine to produce choline and phosphatidic acid (PA). PLD has two isoforms, PLD1 and PLD2, which vary in expression and localization depending on the cell type. The mast cell line RBL-2H3 was transfected to overexpress catalytically active (PLD2CA) and inactive (PLD2CI) forms of PLD2. The results of this study show that PLD2CI cells have a distinct star-shaped morphology, whereas PLD2CA and RBL-2H3 cells are spindle shaped. In PLD2CI cells, the Golgi complex was also disorganized with dilated cisternae, and more Golgi-associated vesicles were present as compared with the PLD2CA and RBL-2H3 cells. Treatment with exogenous PA led to the restoration of the wild-type Golgi complex phenotype in PLD2CI cells. Conversely, treatment of RBL-2H3 and PLD2CA cells with 1% 1-Butanol led to a disruption of the Golgi complex. The distribution of acidic compartments, including secretory granules and lysosomes, was also modified in PLD2CI cells, where they concentrated in the perinuclear region. These results suggest that the PA produced by PLD2 plays an important role in regulating cell morphology in mast cells.     

Transmission Efficacy and Plasticity in Glutamatergic Synapses Formed by Excitatory Interneurons of the Substantia Gelatinosa in the Rat Spinal Cord

Background

Substantia gelatinosa (SG, lamina II) is a spinal cord region where most unmyelinated primary afferents terminate and the central nociceptive processing begins. The glutamatergic excitatory interneurons (EINs) form the majority of the SG neuron population, but little is known about the mechanisms of signal processing in their synapses.

Methodology

To describe the functional organization and properties of excitatory synapses formed by SG EINs, we did non-invasive recordings from 183 pairs of monosynaptically connected neurons. An intact presynaptic SG EIN was specifically stimulated through the cell-attached pipette while the evoked EPSCs/EPSPs were recorded through perforated-patch from a postsynaptic neuron (laminae I-III).

Principal Findings

We found that the axon of an SG EIN forms multiple functional synapses on the dendrites of a postsynaptic neuron. In many cases, EPSPs evoked by stimulating an SG EIN were sufficient to elicit spikes in a postsynaptic neuron. EPSCs were carried through both Ca²⁺-permeable (CP) and Ca²⁺-impermeable (CI) AMPA receptors (AMPARs) and showed diverse forms of functional plasticity. The synaptic efficacy could be enhanced through both activation of silent synapses and strengthening of already active synapses. We have also found that a high input resistance (R_IN, >0.5 GΩ) of the postsynaptic neuron is necessary for resolving distal dendritic EPSCs/EPSPs and correct estimation of their efficacy.

Conclusions/Significance

We conclude that the multiple synapses formed by an SG EIN on a postsynaptic neuron increase synaptic excitation and provide basis for diverse forms of plasticity. This functional organization can be important for sensory, i.e. nociceptive, processing in the spinal cord.     

Continuous cultures of <Emphasis Type="Italic">Pseudomonas putida</Emphasis> mt-2 overcome catabolic function loss under real case operating conditions

The long-term performance and stability of Pseudomonas putida mt-2 cultures, a toluene-sensitive strain harboring the genes responsible for toluene biodegradation in the archetypal plasmid pWW0, was investigated in a chemostat bioreactor functioning under real case operating conditions. The process was operated at a dilution rate of 0.1 h⁻¹ under toluene loading rates of 259 ± 23 and 801 ± 78 g m⁻³ h⁻¹ (inlet toluene concentrations of 3.5 and 10.9 g m⁻³, respectively). Despite the deleterious effects of toluene and its degradation intermediates, the phenotype of this sensitive P. putida culture rapidly recovered from a 95% Tol⁻ population at day 4 to approx. 100% Tol⁺ cells from day 13 onward, sustaining elimination capacities of 232 ± 10 g m⁻³ h⁻¹ at 3.5 g Tol m⁻³ and 377 ± 13 g m⁻³ h⁻¹ at 10.9 g Tol m⁻³, which were comparable to those achieved by highly tolerant strains such as P. putida DOT T1E and P. putida F1 under identical experimental conditions. Only one type of Tol⁻ variant, harboring a TOL-like plasmid with a 38.5 kb deletion (containing the upper and meta operons for toluene biodegradation), was identified.     

Changes in hydrogen peroxide homeostasis and cytokinin levels contribute to the regulation of shade-induced senescence in wheat leaves

In a previous work we demonstrated that the suppression of blue light in shaded leaves of wheat increases their senescence rate and the development of oxidative stress symptoms. In order to better understand the interaction between the oxidative metabolism and light spectral quality in the regulation of leaf senescence, we studied the evolution of H₂O₂ concentration, protein oxidation, proteolytic activity and cytokinin content in excised leaves, either illuminated (control, “C”) or shaded under blue (“B”, high blue light transmission) or green (“G”, very low blue light transmission) light filters. H₂O₂ concentration significantly increased during the first 9 h after treatment initiation, an effect that was consistently higher in treatments B and C. Leaves from these treatments showed lower chlorophyll and protein degradation rates, lower concentration of oxidized proteins, and maintained higher levels of the cytokinin isopentenyl-adenosine than those from treatment G. When moderate H₂O₂ concentrations were supplied during 6–9 h after the onset of the shade treatments, senescence rate in treatment G was delayed, while the opposite effect was observed in the presence of the H₂O₂ scavengers catalase and, to a lesser extent, dimethylthiourea. These effects were accompanied by an increment or a decrement, respectively, of catalase activity, suggesting that the early changes in H₂O₂ homeostasis in leaves from treatments B and C may contribute to the prevention rather than to the induction of further oxidative damage. Altogether our results show that the suppression of blue light transmission in shaded leaves act as a stress signal that increases their sensitivity to oxidative stress and accelerates cell death.     

Antimicrobial Activity,Inhibition of Urogenital Pathogens,and Synergistic Interactions Between <Emphasis Type="Italic">Lactobacillus</Emphasis> Strains

Lactobacillus fermentum strain L23 and L. rhamnosus strain L60 were selected as an alternative treatment to prevent or treat urogenital infections based on their probiotic properties and production of bacteriocins. The objectives of the present work were to study the inhibitory activities of these two bacteriocin-producing strains, and to analyze the interactions between pairs of bacteriocins that inhibit urogenital pathogens. Antimicrobial activity tests of L23 and L60 were performed by a diffusion method with 207 bacterial strains, isolated from female patients presenting a urogenital infection. Inhibitory substances interaction tests were carried out by using a streak-diffusion method on agar plates. One hundred percent of the clinical isolates showed sensitivity to the antimicrobial substances produced by L23 and L60. The selected lactobacilli produced larger inhibition halos when compared to several antibiotics commonly used for treating these infections. Synergistic interactions and indifferent interactions were recorded in 68.6% and 31.4% of the cases, respectively. No antagonistic interactions were observed. In conclusion, the bacteriocin-producing strains L23 and L60 are potential candidates for probiotic prophylaxis and treatment of urogenital disorders in women.     

An N-ethyl-N-nitrosourea mutagenesis recessive screen identifies two candidate regions for murine cardiomyopathy that map to chromosomes 1 and 15

N-ethyl-N-nitrosourea (ENU) mutagenesis screens have been successful for identifying genes that affect important biological processes and diseases. However, for heart-related phenotypes, these screens have been employed exclusively for developmental phenotypes, and to date no adult cardiomyopathy-causing genes have been discovered through a mutagenesis screen. To identify novel disease-causing and disease-modifying genes for cardiomyopathy, we performed an ENU recessive mutagenesis screen in adult mice. Using noninvasive echocardiography to screen for abnormalities in cardiac function, we identified a heritable cardiomyopathic phenotype in two families. To identify the chromosomal regions where the mutations are localized, we used a single nucleotide polymorphism (SNP) panel for genetic mapping of mouse mutations. This panel provided whole-genome linkage information and identified the mutagenized candidate regions at the proximal end of chromosome 1 (family EN1), and at the distal end of chromosome 15 (family EN25). We have identified 94 affected mice in family EN1 and have narrowed the candidate interval to 1 Mb. We have identified 20 affected mice in family EN25 and have narrowed the candidate interval to 12 Mb. The identification of the genes responsible for the observed phenotype in these families will be strong candidates for disease-causing or disease-modifying genes in patients with heart failure. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Charge effect on the photoinactivation of Gram-negative and Gram-positive bacteria by cationic meso-substituted porphyrins

Background  

In recent times photodynamic antimicrobial therapy has been used to efficiently destroy Gram (+) and Gram (-) bacteria using cationic porphyrins as photosensitizers. There is an increasing interest in this approach, namely in the search of photosensitizers with adequate structural features for an efficient photoinactivation process. In this study we propose to compare the efficiency of seven cationic porphyrins differing in meso-substituent groups, charge number and charge distribution, on the photodynamic inactivation of a Gram (+) bacterium (Enterococcus faecalis) and of a Gram (-) bacterium (Escherichia coli). The present study complements our previous work on the search for photosensitizers that might be considered good candidates for the photoinactivation of a large spectrum of environmental microorganisms.