Classificação Morfológica e Genotípica e Correlação Entre Propriedades Fisiológicas e Citopatogênicas de Isolados Clínicos e Ambientais de Acanthamoeba

Amebas de vida livre do gênero Acanthamoeba podem eventualmente sobreviver como parasitas, causando infecções graves no homem e em outros animais. Algumas características biológicas e fisiológicas têm sido relacionadas ao nível de patogenicidade das cepas, o que permite inferir sobre o potencial patogênico do gênero. O objetivo deste estudo foi classificar isolados de Acanthamoeba obtidos no Brasil, avaliar suas propriedades de patogenicidade e discutir os resultados com base na origem dos mesmos. Um total de 39 isolados obtidos de casos de ceratite amebiana (n=16) e de amostras ambientais (n=23) foram classificados em grupos morfológicos (I, II, III) e genotipados (T1-T20) pelo sequenciamento dos fragmentos ASA.S1 e GTSA.B1 do gene 18S rDNA. Para a caracterização, foram utilizados os ensaios de termotolerância, osmotolerância e de citopatogenicidade em células MDCK. Os resultados dos isolados clínicos e ambientais foram comparados pelo teste do x2 (p<0,05). A classificação foi realizada como segue: grupo I (T17, T18); grupo II (T1, T3, T4, T11); e grupo III (T5, T15), com predominância do genótipo T4 (22/39). Os isolados clínicos foram identificados como T3 (1/16), T4 (14/16) e T5 (1/16). A maioria dos isolados (38/39) cresceu a 37 °C, mas a tolerância a 40 °C foi mais observada entre os isolados ambientais. A tolerância a 1 M de manitol foi infrequente (4/39), sendo que três desses isolados são de origem clínica. Não houve diferença significativa entre os números de isolados clínicos e ambientais com tolerância a 40 °C (p=0,06), a 1 M de manitol (p=0,14) e com a capacidade de causar efeito citopático (p=0,59). E foi observada uma correspondência variável dessas propriedades entre os diferentes genótipos. Este estudo identifica, pela primeira vez, os genótipos T1, T15 e T18 no Brasil. Além disso, demonstra que há pouca correlação entre a origem clínica dos isolados e os testes fisiológicos de tolerância e citopatogenicidade, o que comprova que alguns parâmetros in vitro não refletem necessariamente uma maior propensão de Acanthamoeba para causar doenças

Potencial alelopático de Annona crassiflora: efeitos sobre plantas daninhas.

A alelopatia pode oferecer novas substâncias químicas com propriedades herbicidas menos prejudiciais ao ambiente e ao homem do que os sintéticos em uso na atual agricultura. Nesse contexto, foi avaliado o efeito de extratos de Annona crassiflora sobre a germinação e o desenvolvimento de Brachiaria brizantha, Euphorbia heterophylla e Ipomoea grandifolia, bem como o efeito do extrato mais promissor sobre a soja (Glycine max). Para isso, foram preparados extratos hidroalcoólicos de sementes, folhas e caules de A. crassiflora, a fim de serem avaliados em testes de germinação e desenvolvimento das plantas daninhas. O extrato da parte mais promissora da planta foi fracionado, utilizando-se solventes em ordem crescente de polaridade. Em relação às partes da planta de A. crassiflora avaliadas, o extrato hidroalcoólico preparado a partir das sementes proporcionou maior interferência nas plantas daninhas; a germinação das sementes de Brachiaria brizantha e Euphorbia heterophylla foi totalmente inibida por esse extrato. De modo geral, as espécies receptoras foram mais sensíveis à fração acetato de etila, mas esta não influenciou o desenvolvimento da soja. Portanto, A. crassiflora apresenta potencial para o manejo de B. brizantha, E. heterophylla e I. grandifolia, em pós-emergência na cultura da soja

Transcriptomic and proteomic analyses of seasonal photoperiodism in the pea aphid

<p>Abstract</p> <p>Background</p> <p>Aphid adaptation to harsh winter conditions is illustrated by an alternation of their reproductive mode. Aphids detect photoperiod shortening by sensing the length of the night and switch from viviparous parthenogenesis in spring and summer, to oviparous sexual reproduction in autumn. The photoperiodic signal is transduced from the head to the reproductive tract to change the fate of the future oocytes from mitotic diploid embryogenesis to haploid formation of gametes. This process takes place in three consecutive generations due to viviparous parthenogenesis. To understand the molecular basis of the switch in the reproductive mode, transcriptomic and proteomic approaches were used to detect significantly regulated transcripts and polypeptides in the heads of the pea aphid <it>Acyrthosiphon pisum</it>.</p> <p>Results</p> <p>The transcriptomic profiles of the heads of the first generation were slightly affected by photoperiod shortening. This suggests that trans-generation signalling between the grand-mothers and the viviparous embryos they contain is not essential. By analogy, many of the genes and some of the proteins regulated in the heads of the second generation are implicated in visual functions, photoreception and cuticle structure. The modification of the cuticle could be accompanied by a down-regulation of the <it>N</it>-β-alanyldopamine pathway and desclerotization. In <it>Drosophila</it>, modification of the insulin pathway could cause a decrease of juvenile hormones in short-day reared aphids.</p> <p>Conclusion</p> <p>This work led to the construction of hypotheses for photoperiodic regulation of the switch of the reproductive mode in aphids.</p

Defective monocyte oxidative burst predicts infection in alcoholic hepatitis and is associated with reduced expression of NADPH oxidase

Objective In order to explain the increased susceptibility to serious infection in alcoholic hepatitis, we evaluated monocyte phagocytosis, aberrations of associated signalling pathways and their reversibility, and whether phagocytic defects could predict subsequent infection. Design Monocytes were identified from blood samples of 42 patients with severe alcoholic hepatitis using monoclonal antibody to CD14. Phagocytosis and monocyte oxidative burst (MOB) were measured ex vivo using flow cytometry, luminometry and bacterial killing assays. Defects were related to the subsequent development of infection. Intracellular signalling pathways were investigated using western blotting and PCR. Interferon-γ (IFN-γ) was evaluated for its therapeutic potential in reversing phagocytic defects. Paired longitudinal samples were used to evaluate the effect of in vivo prednisolone therapy. Results MOB, production of superoxide and bacterial killing in response to Escherichia coli were markedly impaired in patients with alcoholic hepatitis. Pretreatment MOB predicted development of infection within two weeks with sensitivity and specificity that were superior to available clinical markers. Accordingly, defective MOB was associated with death at 28 and 90 days. Expression of the gp91phox subunit of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase was reduced in patients with alcoholic hepatitis demonstrating defective MOB. Monocytes were refractory to IFN-γ stimulation and showed high levels of a negative regulator of cytokine signalling, suppressor of cytokine signalling-1. MOB was unaffected by 7 days in vivo prednisolone therapy. Conclusions Monocyte oxidative burst and bacterial killing is impaired in alcoholic hepatitis while bacterial uptake by phagocytosis is preserved. Defective MOB is associated with reduced expression of NADPH oxidase in these patients and predicts the development of infection and death

Multidisciplinary recommendations for essential baseline functional and laboratory tests to facilitate early diagnosis and management of immune-related adverse events among cancer patients.

Immune checkpoint inhibitors (ICIs) have fundamentally changed the treatment landscape of various cancers. While ICI treatments result in improved survival, quality of life and are cost-effective, the majority of patients experience at least one immune-related adverse event (irAE). Many of these side effects cause little discomfort or are asymptomatic; however, irAEs can affect any organ and are potentially life-threatening. Consequently, early diagnosis and appropriate treatment of irAEs are critical for optimizing long-term outcomes and quality of life in affected patients. Some irAEs are diagnosed according to typical symptoms, others by abnormal findings from diagnostic tests. While there are various guidelines addressing the management of irAEs, recommendations for the early recognition of irAEs as well as the optimal extent and frequency of laboratory tests are mostly lacking. In clinical practice, blood sampling is usually performed before each ICI administration (i.e., every 2-3 weeks), often for several months, representing a burden for patients as well as health care systems. In this report, we propose essential laboratory and functional tests to improve the early detection and management of irAEs and in cancer patients treated with ICIs. These multidisciplinary expert recommendations regarding essential laboratory and functional tests can be used to identify possible irAEs at an early time point, initiate appropriate interventions to improve patient outcomes, and reduce the burden of blood sampling during ICI treatment