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Some wild species of the genus Oryza such as O. rufipogon and O. longistaminata show a high level of resistance to pests and diseases including rice blast (caused by Magnaporthe grisea). To transfer blast resistance from wild species into cultivatedvarieties (O. sativa), interspecific hybrids were produced and anther culture was used toaccelerate the procedure of resistance breeding. Anther culture efficiency depended onboth the medium and the genotype of the cultivated varieties and the wild species. Afterinoculation with a mixture of six strains with wide spectrum virulence, all the F1 hybridswere resistant to blast; the F2 plants segregated, from high resistance to susceptibility, anda similar result was obtained for the H1 and H2 plants. At the H3 stage, blast resistancetended to be stable and almost 100% of inoculated H5 plants were highly resistant to riceblast. For agronomic characteristics, the F2 and H1 showed segregation, but no significantdifferences were seen between the cultivated parents and the H2 to H5 generations. Theresults demonstrate that blast resistance genes can be transferred from wild rice speciesinto cultivated varieties through crossing and anther culture, and the H5 can be used asstable lines in future breeding programmes.

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Cereal Research Communications
Authors: Doris Lucyshyn, Shamsozoha Abolmaali, Hanna Weindorfer, Mehrdad Shams, Gerlinde Wiesenberger, Eva Wilhelm, Marc Lemmens and Gerhard Adam

The production of the trichothecene mycotoxin deoxynivalenol (DON) is an important virulence factor of the plant pathogenic fungus Fusarium graminearum on wheat. We have engineered a DON sensitive yeast strain and constructed a cDNA library from DON treated wheat suspension culture cells in a yeast expression vector. The library was used to select DON resistance conferring clones. Besides ORFs of unknown function, we found 3 classes of cDNAs that in addition to DON resistance conferred hypersensitivity to hygromycin and canavanine. The predicted functions of several of the wheat cDNAs (putative E3 ligase, ubiquitin specific protease, proteasome subunit) suggested a role for ubiquitin-proteasome mediated protein degradation in DON resistance. Results with a coupled wheat germ in vitro translation system and a GUS-luciferase fusion gene showed that DON is a powerful translation elongation inhibitor. The truncated proteins formed in the presence of DON most likely lead to ubiquitin depletion and consequently growth inhibition in yeast. Ubiquitin is essential for many processes in plants, including plant defense. Our results warrant the re-evaluation of the relevance of proteasome system components found to be differentially regulated during Fusarium infection.

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Acta Microbiologica et Immunologica Hungarica
Authors: L. Kredics, Zsuzsanna Antal, A. Szekeres, L. Hatvani, L. Manczinger, Cs. Vágvölgyi and Erzsébet Nagy

Cellulolytic, xylanolytic, chitinolytic and b-1,3-glucanolytic enzyme systems of species belonging to the filamentous fungal genus Trichoderma have been investigated in details and are well characterised. The ability of Trichoderma strains to produce extracellular proteases has also been known for a long time, however, the proteolytic enzyme system is relatively unknown in this genus. Fortunately, in the recent years more and more attention is focused on the research in this field. The role of Trichoderma proteases in the biological control of plant pathogenic fungi and nematodes has been demonstrated, and it is also suspected that they may be important for the competitive saprophytic ability of green mould isolates and may represent potential virulence factors of Trichoderma strains as emerging fungal pathogens of clinical importance. The aim of this review is to summarize the information available about the extracellular proteases of Trichoderma. Numerous studies are available about the extracellular proteolytic enzyme profiles of Trichoderma strains and about the effect of abiotic environmental factors on protease activities. A number of protease enzymes have been purified to homogeneity and some protease encoding genes have been cloned and characterized. These results will be reviewed and the role of Trichoderma proteases in biological control as well as their advantages and disadvantages in biotechnology will be discussed.

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Acta Microbiologica et Immunologica Hungarica
Authors: Ildikó Nyilasi, T. Papp, M. Takó, Erzsébet Nagy and Cs. Vágvölgyi

Iron is an essential nutrient for most organisms because it serves as a catalytic cofactor in oxidation-reduction reactions. Iron is rather unavailable because it occurs in its insoluble ferric form in oxides and hydroxides, while in serum of mammalian hosts is highly bound to carrier proteins such as transferrin, so the free iron concentration is extremely low insufficient for microbial growth. Therefore, many organisms have developed different iron-scavenging systems for solubilizing ferric iron and transporting it into cells across the fungal membrane. There are three major mechanisms by which fungi can obtain iron from the host: (a) utilization of a high affinity iron permease to transport iron intracellularly, (b) production and secretion of low molecular weight iron-specific chelators (siderophores), (c) utilization of a hem oxygenase to acquire iron from hemin. Patients with elevated levels of available serum iron treated with iron chelator, deferoxamine to remedy iron overload conditions have an increased susceptibility of invasive zygomycosis. Presumably deferoxamine predisposes patients to Zygomycetes infections by acting as a siderophore. The frequency of zygomycosis is increasing in recent years and these infections respond very poorly to currently available antifungal agents, so new approaches to develop strategies to prevent and treat zygomycosis are urgently needed. Siderophores and iron-transport proteins have been suggested to function as virulence factors because the acquisition of iron is a crucial pathogenetic event. Biosynthesis and uptake of siderophores represent possible targets for antifungal therapy.

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Pathogenicity and virulence are multifactorial traits, depending on interaction of viruses with susceptible cells and organisms. The ion channels coded by viruses, viroporins, represent only one factor taking part in the cascade of interactions between virus and cell, leading to the entry of virus, replication and to profound changes in membrane permeability. The M2 protein from influenza A virus forms proton-selective, pH-regulated channel involved in regulating vesicular pH, a function important for the correct maturation of HA glycoprotein. The NB glycoprotein of influenza B viruses is an integral membrane protein with an ion channel activity. The CM2 protein of influenza C virus is an integral membrane glycoprotein structurally analogous to influenza A virus M2 and influenza B virus NB proteins. The picornavirus 3A protein is involved in cell lysis and shows homology with other lytic proteins. Vpu is an oligomeric integral membrane protein encoded by HIV-1, which forms ion channels. The togavirus 6K protein shows structural similarities with other viroporins.

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Acta Microbiologica et Immunologica Hungarica
Authors: G. Klausz, Andrea Tiszai, Zsuzsa Lénárt, Zsófia Gyulai, L. Tiszlavicz, Márta Hőgye, M. Csanády, J. Lonovics and Yvette Mándi

The interaction between the bacteria and the host is a key factor determining the clinical consequences of H. pylori infection. The immune system plays an important role in either promoting or preventing the disease. The mucosal production of TNF-a, IL-6, IL-8 and IL-10 and the CagA status were investigated in H. pylori-positive patients with duodenal ulcer (DU). The concentrations of these cytokines in gastric antral mucosal specimens from patients infected with H. pylori (n = 40) were determined by ELISA and compared with data on mucosal specimens from H. pylori-negative patients (n = 12). The local TNF-a, IL-6 and IL-8 concentrations in the antral biopsy samples were significantly higher (p < 0.001) in the patients infected with H. pylori than in the samples from the H. pylori-negative subjects. CagA positivity was demonstrated in 39 (97.5%) of the 40 patients with DU, and in 41 (70.7%) of H. pylori-positive (58 of 100) healthy blood donors. In complementary studies focusing on extragastric disease, it was found that 57% of patients with ischaemic heart disease were seropositive as concerns H. pylori, and 91% of them had antibodies against human heat shock protein 60, too. This study suggests that, besides the bacterial virulence factor, the host response of an increased mucosal production of inflammatory cytokines can be relevant to the gastric pathophysiology in H. pylori-induced DU. At the same time, in ischaemic heart diseases the role of autoimmune processes induced by H. pylori cannot be excluded.

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Advances in medical and surgical therapy over the past two decades have changed the nature of patient care during hospitalization. Recently developed technologies and therapies, involving bone marrow or solid-organ transplants and chemotherapeutic agents, have become common at many medical centers, resulting in the emergence of many immunocompromised individuals. In intensive care units (ICU) the use of invasive monitoring devices, parenteral nutrition, broad-spectrum antimicrobial agents, and assisted ventilation has helped in the treatment of patients suffering from previously devastating or fatal diseases and has provided opportunities for life to premature neonates previously thought to be non-viable [1]. However, these successes have resulted in the proliferation of a severely ill, immunocompromised, long-lasting hospitalized patient population. The AIDS epidemic has also added patients at risk to this growing population of immunocompromised individuals [2]. The immunocompromised patient is highly susceptible to nosocomial infections caused by organisms such as fungi that were previously considered to be of low virulence or „non-pathogenic” [3]. Besides the well-known endemic fungal pathogens (Histoplasma capsulatumCoccidioides immitisandBlastomyces dermatitidis), opportunisticCandidaspecies have been implicated most frequently in nosocomial fungal infections.

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Orvosi Hetilap
Authors: Veronika Müller, Zsuzsanna Kováts and Gábor Horváth

A létfontosságú szervek elégtelenségének kezelésében a szervtranszplantáció a napi gyakorlat része. A recipiensek közös jellemzője, hogy immunszuppresszív kezelést igényelnek a szervkilökődés megakadályozása érdekében. Az immunszuppresszió növeli az infekcióhajlamot, különösen az egyébként alacsony virulenciájú opportunista kórokozókkal szemben. A szervtranszplantáltak fertőzéseinek jelentős része a tüdőt és a légutakat érinti. Az infekciós komplikációk felismerésében a pulmonológiai diagnosztika, magas szintű mikrobiológiai eljárások és a különböző képalkotó technikák alkalmazhatók. A terápia fejlődése és elérhetősége elengedhetetlen az infekciók eredményes kezeléséhez. Tekintve, hogy a szervtranszplantáltak száma folyamatosan nő, az orvos mind nagyobb számban találkozhat vese-, máj-, szív- vagy tüdőtranszplantált betegek pulmonalis komplikációival. Orv. Hetil., 2012, 153, 899–903.

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Orvosi Hetilap
Authors: István László, Csilla Molnár, György Koszta, Tamás Végh, Ákos Fábián, Mariann Berhés, Marianna Juhász and Béla Fülesdi

Absztrakt:

A világunkon végigvonuló koronavírus-járvány számos kihívással szembesíti az egészségügyben dolgozókat. A vírus cseppfertőzéssel terjed, és magas a virulenciája, ezért minden olyan beavatkozás, mely légúti aeroszolképződést generál, potenciálisan veszélyezteti az ellátásban részt vevők egészségét. A koronavírus-fertőzés súlyos formája progresszív légzési elégtelenséggel jár, melynek ellátásában a korai endotrachealis intubáció és invazív gépi lélegeztetés elengedhetetlen. Az intubáció során fokozott a légúti aeroszolképződés veszélye, így magas az ellátó személyzet fertőződésének veszélye. Az előzőeken túl ezen betegeknél relatíve gyakori a nehéz légútbiztosítás is. Cikkünk célja, hogy gyakorlatorientált áttekintést adjon a koronavírussal fertőzött betegek légútbiztosításának specialitásairól, különös tekintettel az infekciókontroll és a betegbiztonság szempontjaira. Orv Hetil. 2020; 161(17): 696–703.

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Orvosi Hetilap
Authors: István László, Csilla Molnár, György Koszta, Tamás Végh, Ákos Fábián, Mariann Berhés, Marianna Juhász and Béla Fülesdi

Absztrakt:

A koronavírus-pandémia számos kihívással szembesíti az egészségügyi ellátószemélyzetet. A vírus cseppfertőzéssel terjed, és magas a virulenciája, ezért minden olyan beavatkozás, mely légúti aeroszolképződéssel jár, potenciálisan veszélyezteti az ellátásban részt vevők egészségét. A koronavírus-fertőzés mortalitása akár 10% feletti lehet, ezért a COVID–19-betegek körében gyakori a reanimáció. A reanimáció során fokozott a légúti aeroszolképződés valószínűsége, így magas az ellátószemélyzet fertőződésének a veszélye. Cikkünk célja, hogy gyakorlatorientált áttekintést adjon a koronavírussal fertőzött betegek újraélesztésének specialitásairól. Orv Hetil. 2020; 161(17): 710–712.

Open access