Neonatal ibotenic acid lesions of the ventralhippocampus : the effects of stress on gene expression and apoptosis

Recently, it has been suggested that neurodevelopmental abnormalities underlie schizophrenia. However, it has also been suggested that schizophrenia is a neurodegenerative disease as evidenced by a progressive worsening of symptoms over time. Neurodevelopmental abnormalities may, therefore, create a functionally compromised system that is more susceptible to neuronal atrophy and/or death caused by environmental factors such as stress (a known precipitant of acute psychotic episodes and exacerbant of schizophrenia). This hypothesis was tested using the putative neurodevelopmental model of schizophrenia described by Lipska 'et al'. (1993). The effects of neonatal hippocampal lesions on BDNF mRNA and NMDAR1 mRNA, factors involved in development, cell survival and cell communication, were investigated in adult rats following exposure to a physiological stressor. Apoptosis levels were also investigated in these rats to determine if neurodegeneration was present. Results demonstrate that BDNF mRNA was reduced in the prefrontal cortex and hippocampus of lesioned as compared to sham rats. Increased BNDF mRNA resulted from swim stress in both groups, but the increase in lesioned animals was more pronounced than controls. NMDAR1 mRNA was also reduced in the prefrontal cortex and CA3 and CA1 regions of the hippocampus in lesioned versus sham rats. There was an increase, however, in the dentate gyrus of lesioned versus sham rats. Swim stress increased NMDAR1 mRNA in the prefrontal cortex and decreased it in the hippocampus. There was also an increase in apoptosis in lesioned versus sham rats, with no significant increase in response to stress. Reductions in BDNF mRNA in lesioned versus control animals support the hypothesis that neurodevelopmental lesions may result in a system more susceptible to stressors. Reductions in NMDAR1 mRNA are in accordance with the NMDA glutamate receptor hypofunction theory of schizophrenia. It is possible that reductions in glutamate function can remove the inhibitory effect of GABA, thereby resulting in overexcitation of the system and a potential for neurodegeneration. Increased apoptosis supports the presence of neurodegeneration as an ongoing phenomenon. Even though the effect of acute stress on apoptosis was not significant, the very small increases demonstrated can have significant functional consequences over extended periods of time

Core Fermentation (CoFe) granules focus coordinated glycolytic mRNA localization and translation to fuel glucose fermentation

Glycolysis is a fundamental metabolic pathway for glucose catabolism across biology, and glycolytic enzymes are among the most abundant proteins in cells. Their expression at such levels provides a particular challenge. Here we demonstrate that the glycolytic mRNAs are localized to granules in yeast and human cells. Detailed live cell and smFISH studies in yeast show that the mRNAs are actively translated in granules, and this translation appears critical for the localization. Furthermore, this arrangement is likely to facilitate the higher level organization and control of the glycolytic pathway. Indeed, the degree of fermentation required by cells is intrinsically connected to the extent of mRNA localization to granules. On this basis, we term these granules, core fermentation (CoFe) granules; they appear to represent translation factories, allowing high-level coordinated enzyme synthesis for a critical metabolic pathway.Fil: Morales Polanco, Fabian. University of Manchester; Reino UnidoFil: Bates, Christian. University of Manchester; Reino UnidoFil: Lui, Jennifer. University of Manchester; Reino UnidoFil: Casson, Joseph. University of Manchester; Reino UnidoFil: Solari, Clara Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Pizzinga, Mariavittoria. University of Manchester; Reino UnidoFil: Forte, Gabriela. University of Manchester; Reino UnidoFil: Griffin, Claire. University of Manchester; Reino UnidoFil: Garner, Kirsten E. L.. University of Manchester; Reino UnidoFil: Burt, Harriet E.. University of Manchester; Reino UnidoFil: Dixon, Hannah L.. University of Manchester; Reino UnidoFil: Hubbard, Simon. University of Manchester; Reino UnidoFil: Portela, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Ashe, Mark P.. University of Manchester; Reino Unid

P. brasiliensis virulence is affected by SconC, the negative regulator of inorganic sulfur assimilation

Conidia/mycelium-to-yeast transition of Paracoccidioidesbrasiliensis is a critical step for the establishment of paracoccidioidomycosis, a systemic mycosis endemic in Latin America. Thus, knowledge of the factors that mediate this transition is of major importance for the design of intervention strategies. So far, the only known pre-requisites for the accomplishment of the morphological transition are the temperature shift to 37°C and the availability of organic sulfur compounds. In this study, we investigated the auxotrophic nature to organic sulfur of the yeast phase of Paracoccidioides, with special attention to P. brasiliensis species. For this, we addressed the role of SconCp, the negative regulator of the inorganic sulfur assimilation pathway, in the dimorphism and virulence of this pathogen. We show that down-regulation of SCONC allows initial steps of mycelium-to-yeast transition in the absence of organic sulfur compounds, contrarily to the wild-type fungus that cannot undergo mycelium-to-yeast transition under such conditions. However, SCONC down-regulated transformants were unable to sustain yeast growth using inorganic sulfur compounds only. Moreover, pulses with inorganic sulfur in SCONC down-regulated transformants triggered an increase of the inorganic sulfur metabolism, which culminated in a drastic reduction of the ATP and NADPH cellular levels and in higher oxidative stress. Importantly, the down-regulation of SCONC resulted in a decreased virulence of P. brasiliensis, as validated in an in vivo model of infection. Overall, our findings shed light on the inability of P. brasiliensis yeast to rely on inorganic sulfur compounds, correlating its metabolism with cellular energy and redox imbalances. Furthermore, the data herein presented reveal SconCp as a novel virulence determinant of P. brasiliensis.J.F.M. and J.G.R. were supported by a PhD grant from Fundacao para a Ciencia e Tecnologia (FCT). This work was supported by a grant from FCT (PTDC/BIA-MIC/108309/2008). M. Sturme. and M. Saraiva are Ciencia 2008 fellows. The authors would also like to thank FAPESP (Fundacao para Amparo a Pesquisa do Estado de Sao Paulo) and CNPq (Conselho Nacional de Desenvolvimento Cientifico e Tecnologico) for financial support. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Contrasting Root and Photosynthesis Traits in a Large-Acreage Canadian Durum Variety and Its Distant Parent of Algerian Origin for Assembling Drought/Heat Tolerance Attributes

In Canada, the world's top exporter of high-protein durum, varietal development over its nearly six-decade history has been driven by a quest for yield improvement without compromise on grain protein content and other quality aspects. Pelissier, a landrace selection from Algeria that was introduced into North America more than a century ago and the variety Strongfield that was released in 2004 are notable. Pelissier, known to elaborate more roots and considered as drought tolerant, has been cultivated commercially and thus deemed adapted. Strongfield has Pelissier in its pedigree, and it remains a high-acreage variety. Strongfield was found to elaborate only about half of the root biomass of Pelissier at maturity in greenhouse trials under well-watered conditions. Extended drought stress caused a significant reduction in the root biomass of both lines. However, Pelissier under drought maintained at least as much root biomass as that of Strongfield under well-watered conditions. In comparison to Pelissier, it had a superior photosynthesis rate (27.16 μmol CO2 m−2 s−1), capacity for carboxylation (Vcmax: 132.83 μmol CO2 m−2 s−1) and electron transport/ribulose-1,5–bisphosphate (RuBP) regeneration (Jmax: 265.40 μmol CO2 m−2 s−1); the corresponding values for Pelissier were 19.62 μmol CO2 m−2 s−1, 91.87 μmol CO2 m−2 s−1, and 163.83 μmol CO2 m−2 s−1, respectively, under well-watered conditions. Under short-term/mild drought conditions, the carbon assimilation rate remained stable in Pelissier while it declined in Strongfield to the Pelissier level. However, Strongfield succumbed to extended drought sooner than Pelissier. Photosynthesis in Strongfield but not Pelissier was found to be sensitive to high temperature stress. These results provide encouraging prospects for further exploitation of beneficial physiological traits from Pelissier in constructing climate-resilient, agronomically favorable wheat ideotypes

Proanthocyanidin biosynthesis in the seed coat of yellow-seeded, canola quality Brassica napus YN01-429 is constrained at the committed step catalyzed by dihydroflavonol 4-reductase

The yellow seed characteristic in Brassica napus L. is desirable because of its association with higher oil content and better quality of oil-extracted meal. YN01-429 is a yellow-seeded canola-quality germplasm developed in Canada arising from several years of research. Seed-coat pigmentation is due to oxidized proanthocyanidins (PA; condensed tannins) derived from phenylpropanoids and malonyl CoA. We found PA accumulation to be most robust in young seed coats (20 d post anthesis; dpa) of a related black-seeded line N89-53 and only very little PA in YN01-429, which also contained much less extractable phenolics. The flavonol content, however, did not show as great a difference between these two lines. Furthermore, sinapine, a product of the general phenylpropanoid metabolism, was present at comparable levels in the embryos of both lines. Dihydroflavonol reductase (DFR) activity that commits phenolics to PA synthesis was lower in YN01-429 seed coats. The results of Southern blot and in silico analyses were indicative of two copies of the DFR gene in B. napus. Both copies were functional in YN01-429, ruling out homeoallelic repression or silencing, but together they showed very low expression levels (17-fold fewer transcripts) relative to DFR activity in N89-53 seed coats. These results collectively suggest that YN01-429 differs in regulatory circuits that impact the PA synthesis branch much more than the flavonol synthesis branch in the seed coats and such circuits do not impinge upon general phenylpropanoid metabolism in the embryos.Le jaune caracte\ub4ristique des grains du Brassica napus L. est de\ub4sirable, compte tenu de son association avec une haute teneur en huile et une meilleure qualite\ub4 de la farine extraite de l\u2019huile. Le YN01-429 constitue un germplasme a` graine jaune de qualite\ub4 canola re\ub4sultant de plusieurs anne\ub4es de recherches. La pigmentation des te\ub4guments est attribue\ub4e a` des proanthocyanidines oxyde\ub4es (PA; tannins condense\ub4s) de\ub4rive\ub4es de phe\ub4nylpropano\u131\ua8des et du CoA du malonyl. Les auteurs ont trouve\ub4 une plus forte accumulation de PA chez les jeunes te\ub4guments (20 jours apre`s l\u2019anthe`se; dpa) d\u2019une ligne\ub4e apparente\ub4e a` grains noirs N89-53 et tre`s peu de PA chez la ligne\ub4e YN01-429 qui contient a` la fois beaucoup moins de phe\ub4nols extractibles. Cependant, la teneur en flavonols ne montre pas autant de diffe\ub4rences entre ces deux ligne\ub4es. De plus, la sinapine, un produit du me\ub4tabolisme ge\ub4ne\ub4ral des phe\ub4nylpropano\u131\ua8des, se retrouve a` des teneurs comparables chez les embryons des deux ligne\ub4es. L\u2019activite\ub4 de la re\ub4ductase du dihydroflavonol (DFR) qui pousse les phe\ub4nols vers la synthe` se de PA, est plus faible dans les te\ub4guments du YN01-429. Les re\ub4sultats du transfert Southern et des analyses in silico indiquent la pre\ub4sence de deux copies du ge`ne DFR chez le B. napus. Les deux copies sont fonctionnelles chez le YN01- 429, ce qui e\ub4limine la re\ub4pression ou le silencing home\ub4oalle\ub4lique, mais ensemble elles ne montrent que de tre`s faibles degre \ub4s d\u2019expression (transcriptions 17 fois infe\ub4rieures) par rapport a` l\u2019activite\ub4 du DFR chez les te\ub4guments du N89-53. Ces re\ub4- sultats pris dans leur ensemble sugge`rent que le YN01-429 diffe`re a` l\u2019e\ub4chelle des circuits qui agissent sur la ligne de synthe`se des PA beaucoup plus que sur la ligne de synthe`se des flavonols dans les te\ub4guments, et de tels circuits n\u2019affectent pas le me\ub4tabolisme ge\ub4ne\ub4ral des phe\ub4nylpropano\u131\ua8des chez les embryons.Peer reviewed: YesNRC publication: Ye

A prion-like domain of Tpk2 catalytic subunit of protein kinase A modulates P-body formation in response to stress in budding yeast

Low complexity regions are involved in the assembly and disassembly of P-bodies (PBs). Saccharomyces cerevisiae contains three genes encoding the protein kinase A (PKA) catalytic subunit: TPK1, TPK2 and TPK3. Tpk2 and Tpk3 isoforms localize to PBs upon glucose starvation showing different mechanisms and kinetics of accumulation. In contrast to the other two isoforms, Tpk2 harbors a glutamine-rich prion-like domain (PrLD) at the N-terminus. Here we show that the appearance of Tpk2 foci in response to glucose starvation, heat stress or stationary phase was dependent on its PrLD. Moreover, the PrLD of Tpk2 was necessary for efficient PB and stress granule aggregation during stress conditions and in quiescent cells. Deletion of PrLD does not affect the in vitro and in vivo kinase activity of Tpk2 or its interaction with the regulatory subunit Bcy1. We present evidence that the PrLD of Tpk2 serves as a scaffold domain for PB assembly in a manner that is independent of Pat1 phosphorylation by PKA. In addition, a mutant strain where Tpk2 lacks PrLD showed a decrease of turnover of mRNA during glucose starvation. This work therefore provides new insight into the mechanism of stress-induced cytoplasmic mRNP assembly, and the role of isoform specific domains in the regulation of PKA catalytic subunit specificity and dynamic localization to cytoplasmic RNPs granules.Fil: Barraza, Carla Eliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Solari, Clara Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Rinaldi, Jimena Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Ojeda, Lucas Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Rossi, Silvia Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Ashe, Mark P.. University Of Manchester. Faculty Of Life Sciences; Reino UnidoFil: Portela, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentin

PKA isoforms coordinate mRNA fate during nutrient starvation

A variety of stress conditions induce mRNA and protein aggregation into mRNA silencing foci, but the signalling pathways mediating these responses are still elusive. Previously we demonstrated that PKA catalytic isoforms Tpk2 and Tpk3 localise with processing and stress bodies in Saccharomyces cerevisiae. Here, we show that Tpk2 and Tpk3 are associated with translation initiation factors Pab1 and Rps3 in exponentially growing cells. Glucose starvation promotes the loss of interaction between Tpk and initiation factors followed by their accumulation into processing bodies. Analysis of mutants of the individual PKA isoform genes has revealed that the TPK3 or TPK2 deletion affects the capacity of the cells to form granules and arrest translation properly in response to glucose starvation or stationary phase. Moreover, we demonstrate that PKA controls Rpg1 and eIF4G1 protein abundance, possibly controlling cap-dependent translation. Taken together,our data suggest that the PKA pathway coordinates multiple stages in the fate of mRNAs in association with nutritional environment and growth status of the cell. © 2012.Fil: Tudisca, Vanesa Romina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; ArgentinaFil: Simpson, Clare. University of Manchester; Reino UnidoFil: Castelli, Lydia. University of Manchester; Reino UnidoFil: Lui, Jennifer. University of Manchester; Reino UnidoFil: Hoyle, Nathaniel. University of Manchester; Reino UnidoFil: Moreno, Silvia Margarita. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; ArgentinaFil: Ashe, Mark. University of Manchester; Reino UnidoFil: Portela, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentin

QTL mapping and molecular characterization of the classical D locus controlling seed and flower color in Linum usitatissimum (flax)

Abstract The flowers of flax (linseed) are blue-hued, ephemeral and self-pollinating, and the seeds are typically brown. A century-old interest in natural yellow seed variants and a historical model point to recessive alleles in B1, D and G loci being responsible, but the functional aspects had remained unknown. Here, we characterized the “D” locus by quantitative trait loci (QTL) mapping and identified a FLAVONOID 3′5′ HYDROXYLASE (F3′5′H) gene therein. It does not belong to the F3′5′H clade, but resembles biochemically characterized F3′Hs (flavonoid 3′ hydroxylase) but without F3′H activity. The genome lacks other F3′H or F3′H-like genes. The apparent neo-functionalization from F3′H is associated with a Thr498 → Ser498 substitution in a substrate recognition site (SRS). The yellow seed and white flower phenotypes of the classical d mutation was found to be due to one nucleotide deletion that would truncate the deduced product and remove three of the six potential SRS, negatively impacting delphinidin synthesis. Delphinidin is sporadic in angiosperms, and flax has no known pollination syndrome(s) with functional pollinator group(s) that are attracted to blue flowers, raising questions on the acquisition of F3′5′H. The appearance of d allele is suggestive of the beginning of the loss of F3′5′H in this species

The role of PKA in the translational response to heat stress in Saccharomyces cerevisiae

Cellular responses to stress stem from a variety of different mechanisms, including translation arrest and relocation of the translationally repressed mRNAs to ribonucleoprotein particles like stress granules (SGs) and processing bodies (PBs). Here, we examine the role of PKA in the S. cerevisiae heat shock response. Under mild heat stress Tpk3 aggregates and promotes aggregation of eIF4G, Pab1 and eIF4E, whereas severe heat stress leads to the formation of PBs and SGs that contain both Tpk2 and Tpk3 and a larger 48S translation initiation complex. Deletion of TPK2 or TPK3 impacts upon the translational response to heat stress of several mRNAs including CYC1, HSP42, HSP30 and ENO2. TPK2 deletion leads to a robust translational arrest, an increase in SGs/PBs aggregation and translational hypersensitivity to heat stress, whereas TPK3 deletion represses SGs/PBs formation, translational arrest and response for the analyzed mRNAs. Therefore, this work provides evidence indicating that Tpk2 and Tpk3 have opposing roles in translational adaptation during heat stress, and highlight how the same signaling pathway can be regulated to generate strikingly distinct physiological outputs.Fil: Barraza, Carla Eliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Solari, Clara Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Marcovich, Irina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Kershaw, Christopher. University of Manchester; Reino UnidoFil: Galello, Fiorella Ariadna. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Rossi, Silvia Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Ashe, Mark P.. University of Manchester; Reino UnidoFil: Portela, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentin