Bakteriális gének szerepe a szimbiotikus gümő inváziójában = The role of bacterial genes in the invasion of the symbiotic nodule

Hoszú távú célunk, hogy megértsük a szimbiotikus nitrogénkötő gümő kifejlődését, és azonosítsuk az invázióban fontos bakteriális géneket. E pályázatban feladatunk volt, hogy (i) elemezzük azon rkp géneket, melyek a Sinorhizobium meliloti 41 törzs specifikus KR5 kapszuláris poliszacharidjának bioszintézisében vesznek részt, (ii) meghatározzuk pontos funkcióját a pha géneknek, melyekről feltételeztük, hogy a pH-homeosztázisban fontosak. Fágreceptorban hibás baktérium és host range fág mutánsok molekuláris genetikai elemzése révén kimutattuk, hogy a 16-3 fág receptorának fontos alkotója az RkpM fehérje, és azonosítottuk a fág h génjét, mely a farki rost fehérjét kódolja. A KR5 antigénről kimutattuk, hogy csak a szimbiotikus gümő inváziójakor fontos, de nem alkotója a fágreceptornak. Befejeztük a DNS-szekvencia meghatározást az rkp-3 régióban, és vizsgáltuk az azonosított gének szerepét. Egyes és kettős rkpY mutánsok segítségével, amelyekben a második mutáció különböző rkp génekben volt kimutattuk, hogy (i) az rkpY mutánsok által termelt poliszacharid nem prekurzora a KR5 antigénnek, és hogy (ii) az rkpR gén ennek az új poliszacharidnak a bioszintézisében játszik szerepet. A pha gének szerepét kifordított membrán vezikulákon végzett fiziológiai kísérletekben vizsgáltuk. Kimutattuk, hogy a K+ adás proton kiáramlást eredményez, ami alátámasztja korábbi feltételezésünket, hogy e gének egy K+/H+ antiportert kódolnak. | Our long term goal is to understand the development of nitrogen fixing symbiotic nodule and to identify bacterial genes involved in the invasion. In this project we focus on (i) the analysis of the rkp genes involved in the biosynthesis of the strain specific KR5 polysaccharide of Sinorhizobium meliloti 41, and (ii) analysis of function of pha gene clusters presumed to be important in pH-homeostasis. The molecular genetic analysis of phage receptor bacterial and host-range phage mutants resulted in the identification of the RkpM protein as an essential part of the 16-3 phage receptor, and in the identification of h gene of the phage encoding the tail-fiber protein. The KR5 antigen were shown only to be important in the invasion of symbiotic nodule but not in the structure of phage receptor. DNA-sequence analysis of the rkp-3 region was completed and the role of the identified genes were examined. Using single and double rkpY mutants, where the second mutations were in different rkp genes, it was shown that (i) the polysaccharide produced by the rkpY mutant was not a precursor of the KR5 antigen, (ii) the rkpR gene is involved in the synthesis of this new polysaccharide. The role of the pha genes were examined on everted membrane vesicles. It was shown that addition of K+ results in proton efflux supporting our hypothesis that pha genes encode for a K+/H+ antiporter

Na efikasnost H-klopki utječe izloženost suncu

In recent years, H-trap-type insect traps have been used to reduce horsefly densities. We investigated the impact of the factors affecting the efficacy of H-traps. Catching data of 15 H-traps were analyzed. The traps were deployed at an outdoor equestrian paddock (Sántos, Somogy county) from May to July 2018. In twelve weeks, the traps collected 10,556 horsefly specimens, dominated by Tabanus autumnalis and Haematopota italica. In the first experiment we found that the distribution of caught individuals was inhomogeneous among the samples. According to the amount of caught individuals, trap efficacy showed spatial and temporal inhomogeneity. In the second experiment, after the rearrangement of traps, we found that traps placed in open, sunny places in the centerline area caught significantly more horseflies than those in shady border regions. It can be concluded that the positioning of H-traps in sunny areas significantly enhances their tabanid-catching efficacy.Posljednjih godina za smanjivanje gustoće obada koriste se klopke H-tipa. Istraživali smo utjecaj različitih čimbenika na efikasnost H-klopki. U radu se analiziraju podaci o ulovu 15 H-klopki. Klopke su bile aktivirane unutar ograde za konje (Sántos, županija Somogy) od svibnja do srpnja 2018. u 12 tjedana klopke su prikupile 10.556 primjeraka obada, među kojima su dominirale vrste Tabanus autumnalis i Haematopota italica. U prvom pokusu utvrdili smo da je zastupljenost uhvaćenih vrsta među uzorcima nehomogena. Klopke su pokazivale prostornu i vremensku nehomogenost u odnosu na prikupljene primjerke. U drugom pokusu, nakon preraspodjele klopki, utvrdili smo da su klopke postavljene na otvorene sunčana mjesta na središnjoj liniji plohe uhvatile značajno više obada nego one u sjenovitim graničnim područjima. Može se zaključiti da smještanje H-klopki na sunčana mjesta znatno povećava njihovu efikasnost prikupljanja obada

Genome characterization of a novel megrivirus-related avian picornavirus from a carnivorous wild bird, western marsh harrier (Circus aeruginosus)

In this study, the complete genome of a novel picornavirus called harrier picornavirus 1 (HaPV-1) strain harrier/MR-01/HUN/2014 (KY488458) was sequenced and analysed from a cloacal sample of a threatened, carnivorous wild bird, western marsh harrier (Circus aeruginosus). HaPV-1 was detectable from 2 of the 3 samples from harriers. HaPV-1 is phylogenetically related to megriviruses (genus Megrivirus) from domestic chicken, turkey and duck, showing a similar genome organization pattern; it also has an avian picornavirus-like "Unit A" motif in the 3' UTR. Unlike the type-IV internal ribosomal entry site (IRES) of megriviruses, HaPV-1 is predicted to contain a type-II-like IRES, suggesting modular exchange of IRES elements between picornavirus genomes

Do the European Great Reed Warblers (Acrocephalus arundinaceus) reach South Africa during wintering?

Former studies have shown that the Great Reed Warbler (Acrocephalus arundinaceus) has two genetically distinguishable haplogroups (a ‘‘western’’ and an ‘‘eastern’’ clade). The species occurs in South Africa from January to late March, yet, in the whole database of EURING, there are no recoveries to the south of the Congo. There are at least three hypotheses concerning which birds are seen wintering in South Africa: (1) the European breeders reach South Africa, but there are no ringing recoveries; (2) a mixed population of birds originating from Turkey, Iran and Kazakhstan (Near and Middle East) winters in South Africa; and (3) birds from Europe and the Near and Middle Eastern populations both reach South Africa. We have sequenced a 492-bp part of the mtDNA control region II in 146 samples from five European breeding and one South African wintering population of Great Reed Warblers. The results show that over 60% of the wintering birds in South Africa carry European haplotypes, belonging to both ‘‘eastern’’ and ‘‘western’’ clades. Since the exact haplotypic constitution of the Near and Middle Eastern populations are not known to us, we cannot exclude that a mixed wintering population is formed from birds originating from these regions, but it seems more likely that the European breeders reach South Africa

A role for the neurokinin-1 receptor in endotoxin-induced fever in mice

An involvement of substance P and its receptor, the neurokinin-1 (NK1) receptor in the mediation of lipopolysaccharide (LPS)-induced fever has been shown earlier, but no studies have been performed, in which, the development of LPS-induced fever was compared between NK1 knockout (KO) and wild type (WT) mice. Adult NK1 KO and WT mice of both sexes were used. In a telemetry system, we investigated the circadian changes of deep body temperature (Tb) and locomotor activity in freely-moving NK1 KO and WT mice. In a separate set of experiments, mice were habituated to staying inside conical restrainers, then in loosely restrained NK1 KO and WT mice, their Tb and autonomic thermoeffector responses to intraperitoneal LPS (or saline) infusion were recorded. Freely-moving NK1 KO mice were hyperactive during periods of the night, which was accompanied by increased Tb, whilst there was no difference in either the locomotor activity or deep Tb between KO and WT mice during the light phase of the day. Injection of LPS resulted in a marked fever response in the mice of both genotypes (p <0.05). However, when injected with LPS, the increase of Tb in NK1 KO mice was significantly attenuated compared to controls (38.1 ± 0.2 vs. 38.5 ± 0.2°C; p <0.05). The attenuation of the fever response was caused by a reduced elevation of the heat production (oxygen consumption) in the NK1 KO mice as compared to their WT littermates (173 ± 9 vs. 189 ± 6 ml/kg/min; p <0.05). We conclude that the absence of the NK1R results in increased Tb and locomotor activity during the night with no alterations during the light phase of the day. The fever response of the NK1 KO mice is attenuated, which is, at least in part, caused by their reduced LPS-induced elevation of heat production. This work was supported by the Hungarian Scientific Research Fund (Grants PD105532 to A.G.), by the European Union (SROP-4.2.4.A/2-11-1-2012-0001 to E.Pi. and V.T.) and the Janos Bolyai Research Scholarship of the Hungarian Academy of Sciences (to A.G)