Papers by Christopher Johnny Armstrong
Orientador : Victor Pereira ZwienerMonografia (graduação) - Universidade Federal do Paraná, Setor... more Orientador : Victor Pereira ZwienerMonografia (graduação) - Universidade Federal do Paraná, Setor de Palotina, Curso de Graduação em Ciências Biológicas.Inclui referênciasResumo : O presente estudo surgiu da necessidade de verificar a contribuição dos Sistemas Agroflorestais (SAF's) para a conservação e restauração da biodiversidade no Brasil. Para isso foi empregada à técnica de Bibliometria, construída a partir de um banco de dados a fim de identificar as principais áreas de conhecimento e suas diferentes abordagens categóricas, lacunas do conhecimento e as principais inferências dos SAF's para a conservação e restauração da biodiversidade. As classes utilizadas para comparação foram tipo de metodologia (quantitativas ou qualitativas), avaliação de dados do solo, fauna, flora, fatores abióticos, sociais, culturais e econômicos. As plataformas digitais consultadas foram a Embrapa publicações, Google Acadêmico, Portal de Periódicos da CAPES, Revista Brasileira de Agroecologi...
Revista Cultivando o Saber, 2016
The organic system of food production requires a holistic ecosystem management, emphasizing the p... more The organic system of food production requires a holistic ecosystem management, emphasizing the preservation of the environment and human health. Adopts measures that optimize the use of natural resources, while generating quality of life, food sovereignty and economic autonomy, enhancing and elevating the social relations of farmers and consumers. This study focused on the social and economic characteristics of organic producers. We surveyed 22 farmers, members of APOP -Organic Producers Association Palotina. The results showed that the age group of these producers varies between 40 and 60 years. Families are small with usually two or three people involved in productive work. As for education, 38% completed primary school, and 45% high school. The monthly income generally varies from three to just over five minimum wages. Half of the respondents are owners of more than 15 h, while another 30% have lands 10 to 15 ha. Just over half derive their income solely from the production, and 70% use only hand labor family. Could be verified that the APOP is representative for the region. Farmers are optimistic to continue with organic production, understanding that the work of dissemination and awareness needs to expand and attract more consumers.
Journal of Biological Chemistry, 2000
We have previously reported that in thrombin-stimulated human platelets, cytosolic phospholipase ... more We have previously reported that in thrombin-stimulated human platelets, cytosolic phospholipase A 2 (cPLA2) is phosphorylated on Ser-505 by p38 protein kinase and on Ser-727 by an unknown kinase. Pharmacological inhibition of p38 leads to inhibition of cPLA2 phosphorylation at both Ser-505 and Ser-727 suggesting that the kinase responsible for phosphorylation on Ser-727 is activated in a p38-dependent pathway. By using Chinese hamster ovary, HeLa, and HEK293 cells stably transfected with wild type and phosphorylation site mutant forms of cPLA2, we show that phosphorylation of cPLA2 at both Ser-505 and Ser-727 and elevation of Ca 2؉ leads to its activation in agonist-stimulated cells. The p38-activated protein kinases MNK1, MSK1, and PRAK1 phosphorylate cPLA2 in vitro uniquely on Ser-727 as shown by mass spectrometry. Furthermore, MNK1 and PRAK1, but not MSK1, is present in platelets and undergo modest activation in response to thrombin. Expression of a dominant negative form of MNK1 in HEK293 cells leads to significant inhibition of cPLA2mediated arachidonate release. The results suggest that MNK1 or a closely related kinase is responsible for in vivo phosphorylation of cPLA2 on Ser-727.
Febs Letters, 1997
A complementary DNA encoding a novel human protein phosphatase 1 (PP1) glycogen-targetting subuni... more A complementary DNA encoding a novel human protein phosphatase 1 (PP1) glycogen-targetting subunit of molecular mass 33 kDa has been sequenced. PPP1R6 is 31% identical to the glycogen-targetting subunit (G L ) of PP1 from rat liver, 28% identical to the N-terminal region of the glycogentargetting subunit (G M ) from human skeletal muscle and 27% identical to glycogen-targetting subunit PPP1R5. Unlike human PPP1R5 and its murine homologue PTG, whose mRNAs are most abundant in skeletal muscle, heart and liver, PPP1R6 is present at similar levels in a wide variety of tissues. The PPP1R6 is associated with glycogen in muscle but is not subject to the same modes of covalent and allosteric regulation as GM and G L .
Biochemical Journal, 2000
Stress-activated protein kinase 1 (SAPK1), also called c-Jun N-terminal kinase (JNK), becomes act... more Stress-activated protein kinase 1 (SAPK1), also called c-Jun N-terminal kinase (JNK), becomes activated in vivo in response to pro-inflammatory cytokines or cellular stresses. Its full activation requires the phosphorylation of a threonine and a tyrosine residue in a Thr-Pro-Tyr motif, which can be catalysed by the protein kinases mitogen-activated protein kinase kinase (MKK)4 and MKK7. Here we report that MKK4 shows a striking preference for the tyrosine residue (Tyr-185), and MKK7 a striking preference for the threonine residue (Thr-183) in three SAPK1/JNK1 isoforms tested (JNK1 alpha 1, JNK2 alpha 2 and JNK3 alpha 1). For this reason, MKK4 and MKK7 together produce a synergistic increase in the activity of each SAPK1/JNK isoform in vitro. The MKK7 beta variant, which is several hundred-fold more efficient in activating all three SAPK1/JNK isoforms than is MKK7 alpha', is equally specific for Thr-183. MKK7 also phosphorylates JNK2 alpha 2 at Thr-404 and Ser-407 in vitro, Ser-407 being phosphorylated much more rapidly than Thr-183 in vitro. Thr-404/Ser-407 are phosphorylated in unstimulated human KB cells and HEK-293 cells, and phosphorylation is increased in response to an osmotic stress (0.5 M sorbitol). However, in contrast with Thr-183 and Tyr-185, the phosphorylation of Thr-404 and Ser-407 is not increased in response to other agonists that activate MKK7 and SAPK1/JNK, suggesting that phosphorylation of these residues is catalysed by another protein kinase, such as CK2, which also phosphorylates Thr-404 and Ser-407 in vitro. MKK3, MKK4 and MKK6 all show a strong preference for phosphorylation of the tyrosine residue of the Thr-Gly-Tyr motifs in their known substrates SAPK2a/p38, SAPK3/p38 gamma and SAPK4/p38 delta. MKK7 also phosphorylates SAPK2a/p38 at a low rate (but not SAPK3/p38 gamma or SAPK4/p38 delta), and phosphorylation occurs exclusively at the tyrosine residue, demonstrating that MKK7 is intrinsically a 'dual-specific' protein kinase.
Biochemical Journal, 2007
Hormones and growth factors induce the activation of a number of protein kinases that belong to t... more Hormones and growth factors induce the activation of a number of protein kinases that belong to the AGC subfamily, including isoforms of PKA, protein kinase B (also known as Akt), PKC, S6K p70 (ribosomal S6 kinase), RSK (p90 ribosomal S6 kinase) and MSK (mitogen-and stress-activated protein kinase), which then mediate many of the physiological processes that are regulated by these extracellular agonists. It can be difficult to assess the individual functions of each AGC kinase because their substrate specificities are similar. Here we describe the small molecule BI-D1870, which inhibits RSK1, RSK2, RSK3 and RSK4 in vitro with an IC 50 of 10-30 nM, but does not significantly inhibit ten other AGC kinase members and over 40 other protein kinases tested at 100-fold higher concentrations. BI-D1870 is cell permeant and prevents the RSK-mediated phorbol ester-and EGF (epidermal growth factor)-induced phosphorylation of glycogen synthase kinase-3β and LKB1 in human embryonic kidney 293 cells and Rat-2 cells. In contrast, BI-D1870 does not affect the agonist-triggered phosphorylation of substrates for six other AGC kinases. Moreover, BI-D1870 does not suppress the phorbol ester-or EGF-induced phosphorylation of CREB (cAMPresponse-element-binding protein), consistent with the genetic evidence indicating that MSK, and not RSK, isoforms mediate the mitogen-induced phosphorylation of this transcription factor.
Uploads
Papers by Christopher Johnny Armstrong