In vitro characterization of the antimalarial activity and mode of action of new PDEs and DHODH inhibitors against Plasmodium falciparum

A malária é uma das doenças parasitárias mais antigas e continua a ser a que mais mortes provoca mundialmente atualmente. Pode ser causada por cinco espécies distintas de protozoários do género Plasmodium (P. falciparum, P. ovale, P. vivax, P.malariae e P. knowlesi), sendo o P. falciparum a espécie mais letal. O parasita é transmitido ao ser humano pela picada do mosquito fêmea do gênero Anopheles. aquando da refeição sanguínea. Em 2017, a Organização Mundial da Saúde relatou 219 milhões de casos de malaria em todo o mundo, sendo a grande maioria na região subsaariana do continente africano. A doença pode ser classificada como: malária grave e não grave, afetando principalmente crianças com idade inferior a cinco anos. As resistências aos fármacos antimaláricos em uso, bem como a inexistência de uma vacina eficaz e o difícil controlo vectorial são os principais obstáculos no combate à doença. A disseminação das resistências torna imperativo a investigação e síntese de novos compostos com potencial ação antimalárica, capazes de atuar em diversos estádios do desenvolvimento do parasita, rapidamente. Neste trabalho, procedeu-se à caracterização da atividade antimalárica e do modo de ação de compostos sintetizados. Compostos sintetizados para serem inhibidores de fosfodiesterases (PDEs) e de dihydroorotate dehydrogenase (DHODH) parasitárias (enzimas importantes para os diferentes estádios de desenvolvimento de P. falciparum). Para a análise da atividade antimalárica, foi avaliado a velocidade de ação dos compostos, os estádios parasitários em que os compostos têm maior atividade, bem como a sua toxicidade nesses estádios. Foram também otimizados dois protocolos de modo a poder, posteriormente, avaliar a ação dos compostos na produção de espécies reativas de oxigénio (ROS) e na alteração do potencial da membrana mitocondrial do parasita. Avaliando a atividades antimaláricas dos potenciais inibidores de PFPDE, um dos compostos demostrou ser de atuação rápida, com atividade nos dois estádios eritrocitários e ter um efeito citocida nos parasitas. O segundo composto com potencial ação contra os PFPDEs avaliado, demostrou ser de atuação mais lenta, com uma ação predominante nos parasitas no estádio de anel, mas tendo um efeito citocida. O composto com potencial ação contra os PFDHODH demostrou ser de atuação lenta, com uma ação predominante com um efeito citocida nos parasitas no estádio de anel e um efeito citostático nos parasitas no estádio de trofozoítos.Malaria is one of the oldest parasitic diseases and continues to be the one that causes the most deaths worldwide nowadays. It can be caused by five distinct species of Plasmodium (P. falciparum, P. ovale, P. vivax, P.malariae and P. knowlesi), with P. falciparum being the most lethal. The parasite is transmitted to humans by the bite of the female mosquito of the genus Anopheles during the blood meal. In 2017, WHO reported 219 million malaria cases worldwide, with the vast majority in the sub-Saharan region. The disease can be classified as: severe and non-severe malaria, mainly affecting children under five years old. Resistance to antimalarial drugs in use as well as the lack of a effective vaccine and the difficult vectorial control are the main obstacles in the fight against the disease. The dissemination of resistance makes it imperative to investigate and synthesize new compounds with potential antimalarial action, capable of acting at several stages of parasite development, rapidly. In this work, the antimalarial activity and the mode-of-action of synthesized compounds were studied. Compounds synthetized to be phosphodiesterase’s (PDEs) and dihydroorotate dehydrogenase (DHODH) inhibitors (important enzymes for Plasmodium falciparum different stages of development). For the analysis of the antimalarial activity, the speed of action of the compounds was evaluated, the stage-specific activity and toxicity of the compounds were determinate. Two protocols were also optimized, in order to evaluate, later, the action of the compounds, in the production of reactive oxygen species (ROS) and in the alteration of mitochondrial membrane potential. Evaluating the antimalarial activities of the potential inhibitors of PFPDE, one of the compounds was shown to be fast acting with activity in both erythrocyte stages studied and to have a cytocidal effect on the parasites. The second compound with potential action against the PFPDEs evaluated, showed to be of slower action, with a predominant action in the ring-stage parasites, but having a cytocidal effect. The compound with potential action against PFDHODH shown to be a slow acting compound, with a predominant action in the ring-stage parasite and to have a cytocidal effect on the ring-stage parasites and a cytostatic effect on trophozoite-stage parasites

Three Decades of Advances in Arabinogalactan-Protein Biosynthesis.

Arabinogalactan-proteins (AGPs) are a large, complex, and highly diverse class of heavily glycosylated proteins that belong to the family of cell wall hydroxyproline-rich glycoproteins. Approximately 90% of the molecules consist of arabinogalactan polysaccharides, which are composed of arabinose and galactose as major sugars and minor sugars such as glucuronic acid, fucose, and rhamnose. About half of the AGP family members contain a glycosylphosphatidylinositol (GPI) lipid anchor, which allows for an association with the outer leaflet of the plasma membrane. The mysterious AGP family has captivated the attention of plant biologists for several decades. This diverse family of glycoproteins is widely distributed in the plant kingdom, including many algae, where they play fundamental roles in growth and development processes. The journey of AGP biosynthesis begins with the assembly of amino acids into peptide chains of proteins. An N-terminal signal peptide directs AGPs toward the endoplasmic reticulum, where proline hydroxylation occurs and a GPI anchor may be added. GPI-anchored AGPs, as well as unanchored AGPs, are then transferred to the Golgi apparatus, where extensive glycosylation occurs by the action of a variety glycosyltransferase enzymes. Following glycosylation, AGPs are transported by secretory vesicles to the cell wall or to the extracellular face of the plasma membrane (in the case of GPI-anchored AGPs). GPI-anchored proteins can be released from the plasma membrane into the cell wall by phospholipases. In this review, we present an overview of the accumulated knowledge on AGP biosynthesis over the past three decades. Particular emphasis is placed on the glycosylation of AGPs as the sugar moiety is essential to their function. Recent genetics and genomics approaches have significantly contributed to a broader knowledge of AGP biosynthesis. However, many questions remain to be elucidated in the decades ahead

Efecto de la aplicación de abonos foliares y enmiendas orgánicas, sobre el rendimiento de repollo corazón de buey (Brassica oleracea L.), en Chachapoyas, Amazonas

El presente trabajo tuvo como objetivo evaluar la respuesta productiva del repollo corazón de buey (Brassica oleracea L.) a la aplicación de diferentes dosis foliares y enmiendas orgánicas. Para ello se instaló un experimento con 12 tratamientos en los cuales se combinaron dos tipos de enmiendas orgánicas (guano de isla y humus de lombriz), y tres dosis de fertilizante foliar de fórmula 20-20-20. Se evaluaron las variables altura de planta (cm), peso del corazón (gr), diámetro de copa (cm), diámetro de corazón (cm) y peso de la planta (g) en 10 plantas por unidad experimental tres meses después de establecer el experimento, obteniéndose como resultado que  el tratamiento compuesto por guano de isla en una dosis de 7 Tn/Ha más tres aplicaciones de abono foliar en una dosis de 2 Lt/200 Lt de agua, fue superior a los demás tratamientos en las variables peso del corazón, diámetro del corazón y peso total de la planta con 1091,6 g, 45,9 cm y 1868,6 g respectivamente, lográndose incrementar hasta en un 57,2% en rendimiento. Por esta razón, la adición de abonos foliares a los planes de fertilización, mejoran los rendimientos del cultivo, sin embargo hay que tener en cuenta que su incorporación genera mayores gastos e incrementa los costos de producción.</p

Egg-Phosphatidylcholine Attenuates T-Cell Dysfunction in High-Fat Diet Fed Male Wistar Rats

Obesity is associated with immune dysfunction including an impaired T-cell function characterized by a lower IL-2 (proliferation marker) production after stimulation. Phosphatidylcholine (PC), a form of choline mostly found in eggs, has been shown to beneficially modulate T-cell responses during the lactation period by increasing the production of IL-2. To determine the impact of egg-PC as part of a high-fat diet on immune function we randomly fed male Wistar rats one of three diets containing the same amount of total choline but differing in the form of choline: 1—Control low fat [CLF, 10% wt/wt fat, 100% free choline (FC)]; 2— Control high-fat (CHF, 25% wt/wt fat, 100% FC); 3— PC high-fat (PCHF, 25% wt/wt, 100% PC). After 9 weeks of feeding, rats were euthanized. Cell phenotypes and ex vivo cytokine production by splenocytes stimulated with phorbol 12-myristate 13-acetate plus ionomycin (PMA+I), lipopolysaccharide (LPS) and pokeweed (PWM) were measured by flow cytometry and ELISA, respectively. Rats fed the PCHF diet had a lower proportion of CD3+ cells when compared to both the CLF and the CHF. Following PMA+I stimulation, splenocytes from the CHF group produced less IL-2 and TNF-α compared to CLF and PCHF groups. No significant differences in cytokine production were found among groups after LPS and PWM stimulation. Our results show that feeding a high-fat diet impairs T-cell responses, as measured by ex vivo cytokine production, which can be attenuated by providing egg-PC

Study of the B−→Λc+Λˉc−K−B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} decay

The decay $B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-}$ is studied in proton-proton collisions at a center-of-mass energy of $\sqrt{s}=13$ TeV using data corresponding to an integrated luminosity of 5 $\mathrm{fb}^{-1}$ collected by the LHCb experiment. In the $\Lambda_{c}^+ K^{-}$ system, the $\Xi_{c}(2930)^{0}$ state observed at the BaBar and Belle experiments is resolved into two narrower states, $\Xi_{c}(2923)^{0}$ and $\Xi_{c}(2939)^{0}$, whose masses and widths are measured to be $$m(\Xi_{c}(2923)^{0}) = 2924.5 \pm 0.4 \pm 1.1 \,\mathrm{MeV}, \\ m(\Xi_{c}(2939)^{0}) = 2938.5 \pm 0.9 \pm 2.3 \,\mathrm{MeV}, \\ \Gamma(\Xi_{c}(2923)^{0}) = \phantom{000}4.8 \pm 0.9 \pm 1.5 \,\mathrm{MeV},\\ \Gamma(\Xi_{c}(2939)^{0}) = \phantom{00}11.0 \pm 1.9 \pm 7.5 \,\mathrm{MeV},$$ where the first uncertainties are statistical and the second systematic. The results are consistent with a previous LHCb measurement using a prompt $\Lambda_{c}^{+} K^{-}$ sample. Evidence of a new $\Xi_{c}(2880)^{0}$ state is found with a local significance of $3.8\,\sigma$, whose mass and width are measured to be $2881.8 \pm 3.1 \pm 8.5\,\mathrm{MeV}$ and $12.4 \pm 5.3 \pm 5.8 \,\mathrm{MeV}$, respectively. In addition, evidence of a new decay mode $\Xi_{c}(2790)^{0} \to \Lambda_{c}^{+} K^{-}$ is found with a significance of $3.7\,\sigma$. The relative branching fraction of $B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-}$ with respect to the $B^{-} \to D^{+} D^{-} K^{-}$ decay is measured to be $2.36 \pm 0.11 \pm 0.22 \pm 0.25$, where the first uncertainty is statistical, the second systematic and the third originates from the branching fractions of charm hadron decays.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-028.html (LHCb public pages

Measurement of the ratios of branching fractions R(D∗)\mathcal{R}(D^{*}) and R(D0)\mathcal{R}(D^{0})

The ratios of branching fractions $\mathcal{R}(D^{*})\equiv\mathcal{B}(\bar{B}\to D^{*}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(\bar{B}\to D^{*}\mu^{-}\bar{\nu}_{\mu})$ and $\mathcal{R}(D^{0})\equiv\mathcal{B}(B^{-}\to D^{0}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(B^{-}\to D^{0}\mu^{-}\bar{\nu}_{\mu})$ are measured, assuming isospin symmetry, using a sample of proton-proton collision data corresponding to 3.0 fb${ }^{-1}$ of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode $\tau^{-}\to\mu^{-}\nu_{\tau}\bar{\nu}_{\mu}$. The measured values are $\mathcal{R}(D^{*})=0.281\pm0.018\pm0.024$ and $\mathcal{R}(D^{0})=0.441\pm0.060\pm0.066$, where the first uncertainty is statistical and the second is systematic. The correlation between these measurements is $\rho=-0.43$. Results are consistent with the current average of these quantities and are at a combined 1.9 standard deviations from the predictions based on lepton flavor universality in the Standard Model.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-039.html (LHCb public pages

Three Decades of Advances in Arabinogalactan-Protein Biosynthesis.

Arabinogalactan-proteins (AGPs) are a large, complex, and highly diverse class of heavily glycosylated proteins that belong to the family of cell wall hydroxyproline-rich glycoproteins. Approximately 90% of the molecules consist of arabinogalactan polysaccharides, which are composed of arabinose and galactose as major sugars and minor sugars such as glucuronic acid, fucose, and rhamnose. About half of the AGP family members contain a glycosylphosphatidylinositol (GPI) lipid anchor, which allows for an association with the outer leaflet of the plasma membrane. The mysterious AGP family has captivated the attention of plant biologists for several decades. This diverse family of glycoproteins is widely distributed in the plant kingdom, including many algae, where they play fundamental roles in growth and development processes. The journey of AGP biosynthesis begins with the assembly of amino acids into peptide chains of proteins. An N-terminal signal peptide directs AGPs toward the endoplasmic reticulum, where proline hydroxylation occurs and a GPI anchor may be added. GPI-anchored AGPs, as well as unanchored AGPs, are then transferred to the Golgi apparatus, where extensive glycosylation occurs by the action of a variety glycosyltransferase enzymes. Following glycosylation, AGPs are transported by secretory vesicles to the cell wall or to the extracellular face of the plasma membrane (in the case of GPI-anchored AGPs). GPI-anchored proteins can be released from the plasma membrane into the cell wall by phospholipases. In this review, we present an overview of the accumulated knowledge on AGP biosynthesis over the past three decades. Particular emphasis is placed on the glycosylation of AGPs as the sugar moiety is essential to their function. Recent genetics and genomics approaches have significantly contributed to a broader knowledge of AGP biosynthesis. However, many questions remain to be elucidated in the decades ahead