Kontrola kvalitete pri biosintezi aminoacil-tRNA

The fidelity of translation is determined at two major points: the accuracy of aminoacyl-tRNA selection by the ribosomes and synthesis of cognate amino acid/tRNA pairs by aminoacyl-tRNA synthetases (aaRSs) in the course of the aminoacylation reaction. The most important point in aminoacylation is the accurate recognition of cognate substrates coupled with discrimination of non-cognates. While this is generally accomplished by a single enzyme, we have recently found that discrimination against lysine analogues requires the existence of two unrelated lysyl-tRNA synthetases. For other amino acids, initial recognition is not sufficiently accurate with errors being corrected by an intrinsic editing activity. Recent studies indicate how editing prevents the misinterpretation of phenylalanine as tyrosine in the genetic code and have shown the importance of this process in vivo. More recent studies indicate that while these editing reactions are critical in the cytoplasm, some are absent from mitochondria suggesting that the overall fidelity of protein synthesis might be reduced in this compartment.Vjernost translacije bitno ovisi o točnosti dvaju koraka: odabiru aminoacil-tRNA na ribosomu i sintezi ispravnih aminoacil-tRNA pomoću odgovarajućih aminoacil-tRNA-sintetaza u reakciji aminoaciliranja. Najvažniji događaj u aminoaciliranju precizno je prepoznavanje pripadnih supstrata (tRNA i aminokiseline) i diskriminacija nepripadnih. Iako taj posao uglavnom obavlja po jedan enzim za svaki par tRNA : aminokiselina, nedavno smo ustanovili da su za diskriminaciju analoga lizina potrebne dvije različite lizil-tRNA-sintetaze. U nekim drugim slučajevima otkriveno je da su pogreške u odabiru tRNA i njihovih pripadnih aminokiseline i suviše velike, pa je nužan naknadni popravak pogrešnih produkata u reakciji aminoaciliranja, koji također mogu katalizirati neke aminoacil-tRNA-sintetaze. Na primjeru krivog odabira tirozina umjesto fenilalanina, te naknadnog popravka, pokazano je kako je mogućnost korekcije važna u sprečavanju pogrešne translacije genetičkog koda in vivo. Najnovija istraživanja pokazala su da su mehanizmi popravka od ključne važnosti u citoplazmi, no neki se ne zbivaju u mitohondriju, ukazujući na smanjenu ukupnu točnost biosinteze proteina u ovom staničnom odjeljku

From Value Creation to Values Creation: The Entrepreneur Enrichment Program as an Enhancement to Business Plan Competitions

This paper will discuss a co-curricular program innovation, the Entrepreneur Enrichment Program (EEP), within the Fermanian School of Business at Point Loma Nazarene University (PLNU). The EEP seeks to provide an enhancement to traditional collegiate business plan competitions. It is believed by the author that many such competitions unwittingly create an illusion of entrepreneurial success through the development of stylistically attractive and technically acceptable business plans at the expense of providing a more well-balanced personal, professional and relational framework of entrepreneurial and start-up success. It is further contended that overly focusing upon business plan creation and competition may not be the ideal way of transmitting entrepreneurial skills and information to aspiring student-entrepreneurs, especially Christian ones. This paper urges that Christian business schools should consider creating more balanced co-curricular entrepreneurial programs by offering a more relational model of engagement between business mentors and student-entrepreneurs from all academic disciplines and departments. This model should work toward the production of high-quality and market-ready business plans for student-entrepreneur ventures in a modified way from the norm. Ultimately, the EEP seeks to expand the value-creation enterprise of business plans to have the additional component of values-creation

Structural basis of signal sequence surveillance and selection by the SRP–FtsY complex

Signal-recognition particle (SRP)-dependent targeting of translating ribosomes to membranes is a multistep quality-control process. Ribosomes that are translating weakly hydrophobic signal sequences can be rejected from the targeting reaction even after they are bound to the SRP. Here we show that the early complex, formed by Escherichia coli SRP and its receptor FtsY with ribosomes translating the incorrect cargo EspP, is unstable and rearranges inefficiently into subsequent conformational states, such that FtsY dissociation is favored over successful targeting. The N-terminal extension of EspP is responsible for these defects in the early targeting complex. The cryo-electron microscopy structure of this 'false' early complex with EspP revealed an ordered M domain of SRP protein Ffh making two ribosomal contacts, and the NG domains of Ffh and FtsY forming a distorted, flexible heterodimer. Our results provide a structural basis for SRP-mediated signal-sequence selection during recruitment of the SRP receptor

Quality Control During Aminoacyl-tRNA Synthesis

The fidelity of translation is determined at two major points: the accuracy of aminoacyl-tRNA selection by the ribosomes and synthesis of cognate amino acid/tRNA pairs by aminoacyl-tRNA synthetases (aaRSs) in the course of the aminoacylation reaction. The most important point in aminoacylation is the accurate recognition of cognate substrates coupled with discrimination of non-cognates. While this is generally accomplished by a single enzyme, we have recently found that discrimination against lysine analogues requires the existence of two unrelated lysyl-tRNA synthetases. For other amino acids, initial recognition is not sufficiently accurate with errors being corrected by an intrinsic editing activity. Recent studies indicate how editing prevents the misinterpretation of phenylalanine as tyrosine in the genetic code and have shown the importance of this process in vivo . More recent studies indicate that while these editing reactions are critical in the cytoplasm, some are absent from mitochondria suggesting that the overall idelity of protein synthesis might be reduced in this compartment

Effect of Methyl Jasmonate on the Performance of Tetranychus evansi Baker & Pritchard, 1960 (Acari: Tetranychidae) and Phytoseiulus longipes Evans, 1968 (Acari: Phytoseiidae) on Tomato Plants

Inducible anti-herbivore defenses in plants are predominantly regulated by jasmonic acid (JA). The red spider mite Tetranychus evansi Baker & Pritchard, 1960 (Acari: Tetranychidae) is an invasive pest known for its detrimental impact on tomato plants and other Solanaceae crops. Here, we investigated the extent to which T. evansi and the predatory mite Phytoseiulus longipes Evans, 1968 (Acari: Phytoseiidae) are affected by induced JA-defenses. Initially, we artificially induced the JA-response in tomato plants using exogenous methyl jasmonate (MeJA) and subsequently assessed the effect of JA defenses on spider mite by evaluating mortality and oviposition rates. Our findings revealed a higher mortality and lower oviposition rates on plants treated with MeJA compared to non-treated control plants. Furthermore, we examined the predatory mite's predation rates on spider mite eggs produced on MeJA-treated and non-treated tomato plants. The results showed a reduced predation on T. evansi eggs derived from MeJA-treated plants, indicating a potential negative impact of JA-induced defenses on the predator's performance. Finally, we released five predatory females on T. evansi-infested tomato plants treated and non-treated with MeJA, monitoring the predator population density for three generations. Predator population was not affected, as the abundance of larvae and adults was not significantly different between treatments. These findings underscore the negative impact of JA defenses on herbivores and highlight the trade-off it may pose on natural enemies

Micropropagacao in vitro de plantas tetraploides de melancia a partir de explantes de gemas apicais e axilares.

Visando à avaliação de diferentes explantes na micropropagação "in vitro" de melancia (Cítrullus lanatus), foi realizado um experimento no Laboratório de Biotecnologia da Embrapa SemiÁrido, no qual, segmentos do ápice caulinar e das axilas foliares de plantas tetraplóides adultas foram coletados no campo, desinfestados com álcool etílico 70% por 1 min e NaOCI a 1,25% por 20 min

Influência do AIA e AIB no enraizamento do mamoeiro hibrido Tainung 1.

Nesta pesquisa estudou-se a influência das concentrações dos ácidos 3-indolil acético (AIA) e idolbutírico (AIB) na indução de rizogênese em mamoeiro híbrido Tainung 1

DNA-Containing Immunocomplexes Promote Inflammasome Assembly and Release of Pyrogenic Cytokines by CD14+ CD16+ CD64high CD32low Inflammatory Monocytes from Malaria Patients

High levels of circulating immunocomplexes (ICs) are found in patients with either infectious or sterile inflammation. We report that patients with either Plasmodium falciparum or Plasmodium vivax malaria have increased levels of circulating anti-DNA antibodies and ICs containing parasite DNA. Upon stimulation with malaria-induced ICs, monocytes express an NF-kappaB transcriptional signature. The main source of IC-induced proinflammatory cytokines (i.e., tumor necrosis factor alpha [TNF-alpha] and interleukin-1beta [IL-1beta])in peripheral blood mononuclear cells from acute malaria patients was found to be a CD14(+) CD16 (FcgammaRIIIA)(+) CD64 (FcgammaRI)(high) CD32 (FcgammaRIIB)(low) monocyte subset. Monocytes from convalescent patients were predominantly of the classical phenotype (CD14(+) CD16(-)) that produces high levels of IL-10 and lower levels of TNF-alpha and IL-1beta in response to ICs. Finally, we report a novel role for the proinflammatory activity of ICs by demonstrating their ability to induce inflammasome assembly and caspase-1 activation in human monocytes. These findings illuminate our understanding of the pathogenic role of ICs and monocyte subsets and may be relevant for future development of immunity-based interventions with broad applications to systemic inflammatory diseases. IMPORTANCE: Every year, there are approximately 200 million cases of Plasmodium falciparum and P. vivax malaria, resulting in nearly 1 million deaths, most of which are children. Decades of research on malaria pathogenesis have established that the clinical manifestations are often a consequence of the systemic inflammation elicited by the parasite. Recent studies indicate that parasite DNA is a main proinflammatory component during infection with different Plasmodium species. This finding resembles the mechanism of disease in systemic lupus erythematosus, where host DNA plays a central role in stimulating an inflammatory process and self-damaging reactions. In this study, we disclose the mechanism by which ICs containing Plasmodium DNA activate innate immune cells and consequently stimulate systemic inflammation during acute episodes of malaria. Our results further suggest that Toll-like receptors and inflammasomes have a central role in malaria pathogenesis and provide new insights toward developing novel therapeutic interventions for this devastating disease

MASTITE BOVINA POR Prototheca zopfii NA REGIÃO OESTE DO PARANÁ: RELATO DE CASOS

Relatam-se três casos de mastite clínica em vacas da raça Jersey de uma propriedade localizada na região Oeste do estado do Paraná, refratários ao tratamento com antimicrobianos. Após realização de cultura das amostras de leite, foi identificada Prototheca zopfii, uma alga aclorofilada, unicelular, presente em matéria orgânica e resistente a antimicrobianos. Foi indicado o descarte dos animais positivos e, como medida de profilaxia, a higienização de caixas de abastecimento de água e bebedouros, uma vez que o manejo da ordenha e higienização da ordenhadeira era realizada de maneira adequada na propriedade. De acordo com a literatura consultada, este é o primeiro relato de mastite por Prototheca zopfii na região Oeste do Paraná, salientando a importância da realização da cultura de amostras de leite de vacas portadoras de mastite, especialmente em casos refratários ao tratamento