The transsynaptic regulation of the septal-hippocampal cholinergic neurons

There is not yet a complete understanding of the functional interactions among various septal nuclei which regulate hippocampal function. Nevertheless, much has been learned histologically and biochemically about the major connections of the distinct areas of the septal complex and the chemical character of some of these pathways. The cholinergic septal-hippocampal pathway serves as a well defined link between these two important structures of the limbic system. Acetylcholine turnover rates in the hippocampus have been shown to increase or decrease proportionally to the activity of the cholinergic neurons originating in the septum. Moreover, these turnover rates have been shown to be modulated by intraseptal injections of agonists or antagonists of various neurotransmitters or neuromodulators which are stored in various cell groups located in the septum. By coupling this biochemical approach with techniques to study the receptor organization, greater detail concerning the transmitter and cotransmitter interactions among the various neuromodulators can be obtained.     

Modulation of neuritogenesis by astrocyte muscarinic receptors

Astrocytes have been shown to release factors that have promoting or inhibiting effects on neuronal development. However, mechanisms controlling the release of such factors from astrocytes are not well established. Astrocytes express muscarinic receptors whose activation stimulates a robust intracellular signaling, although the role of these receptors in glial cells is not well understood. Acetylcholine and acetylcholine receptors are present in the brain before synaptogenesis occurs and are believed to be involved in neuronal maturation. The present study was undertaken to investigate whether stimulation of muscarinic receptors in astrocytes would modulate neurite outgrowth in hippocampal neurons. Rat hippocampal neurons, co-cultured with rat cortical astrocytes previously exposed to the cholinergic agonist carbachol, displayed longer neurites. The effect of carbachol in astrocytes was due to the activation of M3 muscarinic receptors. Exposure of astrocytes to carbachol increased the expression of the extracellular matrix proteins fibronectin and laminin-1 in these cells. This effect was mediated in part by an increase in laminin-1 and fibronectin mRNA levels and in part by the up-regulation of the production and release of plasminogen activator inhibitor-1, an inhibitor of the proteolytic degradation of the extracellular matrix. The inhibition of fibronectin activity strongly reduced the effect of carbachol on the elongation of all the neurites, whereas inhibition of laminin-1 activity reduced the elongation of minor neurites only. Plasminogen activator inhibitor-1 also induced neurite elongation through a direct effect on neurons. Taken together, these results demonstrate that cholinergic muscarinic stimulation of astrocytes induces the release of permissive factors that accelerate neuronal development.     

Implications of disaggregation procedures on biological representation of human solid tumours

Abstract. This study was designed to define some biological aspects of cell suspensions, obtained by mechanical or enzymatic disaggregations, and to verify whether single cell suspensions are representative of original solid tumours. The study was performed on a series of 25 human solid tumours including breast carcinoma, ovarian carcinoma and malignant melanoma. A higher cell viability and a loss of aneuploid subpopulations, or a lower fraction of aneuploid cells, were observed in enzymatically-released samples than in samples obtained by the mechanical procedure. Moreover, the proliferative activity, which was generally similar for the cell suspensions obtained by the two disaggregation procedures, was always markedly lower in the cell suspensions than in solid samples from the same tumour. In conclusion, the results from this study indicate that many changes, such as selective release of cell populations from the tumour matrix, damage and destruction of aneuploid and proliferating cells can be induced to various extents by different disaggregation procedures.     

Dispersal of Aedes aegypti and Aedes albopictus (Diptera: Culicidae) in an urban endemic dengue area in the State of Rio de Janeiro,Brazil

Experimental releases of female Aedes (Stegomyia) aegypti and Aedes (Stegomyia) albopictus were performed in August and September 1999, in an urban area of Nova Igua u, State of Rio de Janeiro, Brazil, to estimate their flight range in a circular area of 1,600 m where 1,472 ovitraps were set. Releases of 3,055 Ae. aegypti and 2,225 Ae. albopictus females, fed with rubidium (Rb)-marked blood and surgically prevented from subsequent blood-feeding, were separated by 11 days. Rb was detected in ovitrap-collected eggs by atomic emission spectrophotometry. Rb-marked eggs of both species were detected up to 800 m from the release point. Eggs of Ae. albopictus were more numerous and more heterogeneously distributed in the area than those of Ae. aegypti. Eggs positively marked for Rb were found at all borders of the study area, suggesting that egg laying also occurred beyond these limits. Results from this study suggest that females can fly at least 800 m in 6 days and, if infected, potentially spread virus rapidly.     

Cutting edge: TLR9 and TLR2 signaling together account for MyD88-dependent control of parasitemia in Trypanosoma cruzi infection

Activation of innate immune cells by Trypanosoma cruzi-derived molecules such as GPI anchors and DNA induces proinflammatory cytokine production and host defense mechanisms. In this study, we demonstrate that DNA from T. cruzi stimulates cytokine production by APCs in a TLR9-dependent manner and synergizes with parasite-derived GPI anchor, a TLR2 agonist, in the induction of cytokines by macrophages. Compared with wild-type animals, T. cruzi-infected Tlr9(-/-) mice displayed elevated parasitemia and decreased survival. Strikingly, infected Tlr2(-/-)Tlr9(-/-) mice developed a parasitemia equivalent to animals lacking MyD88, an essential signaling molecule for most TLR, but did not show the acute mortality displayed by MyD88(-/-) animals. The enhanced susceptibility of Tlr9(-/-) and Tlr2(-/-)Tlr9(-/-) mice was associated with decreased in vivo IL-12/IFN-gamma responses. Our results reveal that TLR2 and TLR9 cooperate in the control of parasite replication and that TLR9 has a primary role in the MyD88-dependent induction of IL-12/IFN-gamma synthesis during infection with T. cruzi.     

A New Recombinant BCG Vaccine Induces Specific Th17 and Th1 Effector Cells with Higher Protective Efficacy against Tuberculosis

Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis (Mtb) that is a major public health problem. The vaccine used for TB prevention is Mycobacterium bovis bacillus Calmette-Guérin (BCG), which provides variable efficacy in protecting against pulmonary TB among adults. Consequently, several groups have pursued the development of a new vaccine with a superior protective capacity to that of BCG. Here we constructed a new recombinant BCG (rBCG) vaccine expressing a fusion protein (CMX) composed of immune dominant epitopes from Ag85C, MPT51, and HspX and evaluated its immunogenicity and protection in a murine model of infection. The stability of the vaccine in vivo was maintained for up to 20 days post-vaccination. rBCG-CMX was efficiently phagocytized by peritoneal macrophages and induced nitric oxide (NO) production. Following mouse immunization, this vaccine induced a specific immune response in cells from lungs and spleen to the fusion protein and to each of the component recombinant proteins by themselves. Vaccinated mice presented higher amounts of Th1, Th17, and polyfunctional specific T cells. rBCG-CMX vaccination reduced the extension of lung lesions caused by challenge with Mtb as well as the lung bacterial load. In addition, when this vaccine was used in a prime-boost strategy together with rCMX, the lung bacterial load was lower than the result observed by BCG vaccination. This study describes the creation of a new promising vaccine for TB that we hope will be used in further studies to address its safety before proceeding to clinical trials.     

Effect of vitamin D3 on behavioural and biochemical parameters in diabetes type 1‐induced rats

Diabetes is associated with long‐term complications in the brain and reduced cognitive ability. Vitamin D₃ (VD₃) appears to be involved in the amelioration of hyperglycaemia in streptozotocin (STZ)‐induced diabetic rats. Our aim was to analyse the potential of VD₃ in avoiding brain damage through evaluation of acetylcholinesterase (AChE), Na⁺K⁺‐adenosine triphosphatase (ATPase) and delta aminolevulinate dehydratase (δ‐ALA‐D) activities and thiobarbituric acid reactive substance (TBARS) levels from cerebral cortex, as well as memory in STZ‐induced diabetic rats. Animals were divided into eight groups (n = 5): control/saline, control/metformin (Metf), control/VD₃, control/Metf + VD₃, diabetic/saline, diabetic/Metf, diabetic/VD₃ and diabetic/Metf + VD₃. Thirty days after treatment, animals were submitted to contextual fear‐conditioning and open‐field behavioural tests, after which they were sacrificed and the cerebral cortex was dissected. Our results demonstrate a significant memory deficit, an increase in AChE activity and TBARS levels and a decrease in δ‐ALA‐D and Na⁺K⁺‐ATPase activities in diabetic rats when compared with the controls. Treatment of diabetic rats with Metf and VD₃ prevented the increase in AChE activity when compared with the diabetic/saline group. In treated diabetic rats, the decrease in Na⁺K⁺‐ATPase was reverted when compared with non‐treated rats, but the increase in δ‐ALA‐D activity was not. VD₃ prevented diabetes‐induced TBARS level and improved memory. Our results show that VD₃ can avoid cognitive deficit through prevention of changes in important enzymes such as Na⁺K⁺‐ATPase and AChE in cerebral cortex in type 1 diabetic rats. Copyright © 2014 John Wiley & Sons, Ltd.     

Phylogeography of the Petunia integrifolia complex in southern Brazil

In this study, we evaluated the genetic diversity of the Petunia integrifolia species group using a phylogeographical approach, and attempted to understand better its diversification and taxonomy. Plants from five morphological groups were collected, covering a large part of the geographical distribution of most of the species. Two major clades were found in the phylogenetic tree, and an additional lineage, corresponding to P. inflata, was found in the haplotype network obtained for plastid markers. All three lineages are clearly delimited geographically, but, with the exception of P. inflata, the morphological groups were not genetically distinct. Our results suggest that a population expansion after a size reduction resulted in the establishment of two distinct and allopatric groups c. 0.5 Mya, one group occurring in a geologically ancient area, and the other occurring in areas that were under the influence of a series of marine transgressions/regressions at the end of the Pleistocene. These two clades are evolutionarily significant units with significantly different allele frequencies in their nuclear genome and reciprocal monophyly in maternal, uniparentally inherited markers. All our results suggest that the morphology‐based taxonomy in this group does not reflect its evolutionary history, and revision of its species limits should incorporate the distribution of the genetic diversity. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 174 , 199–213.     

Ovule,fruit and seed development in Abolboda (Xyridaceae,Poales): implications for taxonomy and phylogeny

Xyridaceae belongs to the xyrid clade of Poales, but the phylogenetic position of the xyrid families is only weakly supported. Xyridaceae is divided into two subfamilies and five genera, the relationships of which remain unclear. The development of the ovule, fruit and seed of Abolboda spp. was studied to identify characteristics of taxonomic and phylogenetic value. All of the studied species share anatropous, tenuinucellate and bitegmic ovules with a micropyle formed by the inner and outer integuments, megagametophyte development of the Polygonum type, seeds with a tanniferous hypostase, a helobial and starchy endosperm and an undifferentiated embryo, seed coat derived from both integuments with a tanniferous tegmen and a micropylar operculum, and fruits with a parenchymatous endocarp and mesocarp and a sclerenchymatous exocarp. Most of the ovule and seed characteristics described for Abolboda are also present in Xyris and may represent a pattern for the family. Abolboda is distinguished by the ovule type, endosperm formation and the number of layers in the seed coat, in agreement with its classification in Abolbodoideae. The following characteristics link Xyridaceae to Eriocaulaceae and Mayacaceae, supporting the xyrid clade: tenuinucellate, bitegmic ovules; seeds with a tanniferous hypostase, a starchy endosperm and an undifferentiated embryo; and a seed coat with a tanniferous tegmen. A micropylar operculum in the seeds of Abolboda is described for the first time here and may represent a synapomorphy for the xyrids. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 175 , 144–154.