The fast evolution of Plasmopara halstedii (downy mildew) remains a major risk for sunflower crop, as new races of the pathogen are bypassing the resistance of sunflower hybrids. In order to understand the processes which led a new virulence to appear in a local P. halstedii population, the genetic relationships were studied using 12 EST (Expressed Sequence Tag)-derived markers between five progeny isolates of races 300, 304, 314, 704 and 714 and two parental ones of races 100 and 710. All genetic analyses were carried out using five single zoosporangium isolates per P. halstedii isolate. There was no intra-isolate genetic variation among the seven pathogen isolates and five multilocus genotypes (MLG) were identified among the 35 P. halstedii single zoosporangium isolates. The single zoosporangium isolates of races 314, 704 and 714 had an intermediary genetic position between the single zoosporangium isolates of two parental isolates. The single zoosporangium isolates of three isolates of races 100, 300 and 304 were localized in the same genetic clade. Two genetic mechanisms could explain the emergence of new virulence in P. halstedii as a recombination between races and mutations in a clonal lineage.
The human cytomegalovirus (HCMV) major immediate-early (MIE) gene is not transcribed in undifferentiated NTera-2 embryonal carcinoma cells, but is transcribed in their differentiated derivatives, offering a model with which to study the developmental regulation of the activity of a viral gene during the differentiation of these cells. The molecular mechanisms involved in the blockade of the MIE gene expression in undifferentiated NTera2 cells include covalent closure of the circular conformation of the viral genome, silencing of the viral MIE promoter by histone deacetylation, and increases in the expression of negatively regulating transcription factors responsible for the recruitment of the histone deacytylases around the viral MIE promoter (MIEP), resulting in repression of the MIEP in undifferentiated cells. The treatment of NTera2 cells with retinoic acid induces the differentiation of these cells. In HCMV-infected differentiated NTera2 cells, the MIEP becomes associated with hyperacetylated histones, which results in an open structure of chromatin, enhancing the access of DNA- binding factors which positively regulate MIE gene expression and viral replication. This model system contributes to an understanding of HCMV latency and reactivation in vivo in the cells of the myeloid lineage.
Authors:Orsolya Nagy, Anna Nagy, Szilvia Tóth, Bernadett Pályi, Anita Vargáné Koroknai and Mária Takács
Zika virus is a mosquito-borne flavivirus with significant public health concern due to its association with neurological symptoms and intrauterine malformations. Although it is endemic in tropical and subtropical areas, sexual transmission raises the possibility of autochthonous spreading elsewhere. We describe the first laboratory diagnosed imported Zika-infections of Hungary, to highlight the challenges of microbiological identification of the pathogen, caused by serological cross-reactivity and short viremia. Serological examination was carried out using indirect immunofluorescent assay and enzyme-linked immunosorbent assay. Plaque-reduction neutralization test was used for verification purposes. A wide range of clinical specimens: serum, whole-blood, urine, saliva, and semen were analyzed by molecular methods, and sequencing was applied in case of PCR positive results to identify the virus strain. Zika-infected patients with previous vaccination against flaviviruses or possible flavivirus infection in the past showed high serological cross-reactivity, and even cross-neutralizing antibodies were observed. Zika virus RNA could be detected in urine specimen in case of two patients, and in EDTA-anticoagulated whole-blood sample of one patient. The detected strains belong to the Asian lineage of the virus. We presume that serological investigation of imported Zika virus could be altered by infections, vaccination of endemic flaviviruses in Hungary and vice versa.
Authors:Mehrdad Mohammadi, Jila Yavarian, Vajihe Karbasizade, Sharareh Moghim, Bahram Nasr Esfahani and Nafiseh Sadat Hosseini
Human bocavirus (HBoV) was first characterized in nasopharyngeal aspirates from young children with acute respiratory infections. It is prevalent among children with acute wheezing. This study was carried out in order to analyze the infection frequency and coinfection rates of HBoV with respiratory syncytial virus (RSV) and to perform phylogenetic analysis of HBoV in samples of children with acute respiratory infection in Isfahan, Iran. During the time period 2016–2017, altogether 75 respiratory samples from children hospitalized with acute respiratory infection were collected. The samples were first screened for RSV by direct immunofluorescence method and then subjected to detect HBoV DNA by PCR. Genotyping of HBoV-positive samples was conducted by direct sequencing of PCR products using NP and VP1/VP2 genes. Out of 75 respiratory samples, 20 (26.7%) and 10 (13.3%) were positive for RSV and HBoV, respectively. The coinfection rate was 40% (p = 0.048). Considering the seasonal distribution, winter has the highest extent outbreak (p = 0.036). Sequence analysis of positive samples exhibits that all of the isolated HBoV were related to genotype 1 (HBoV-1) with minimal sequence variations. Increasing frequency of HBoV suggests that the virus is related to acute respiratory infection in children. A single genetic lineage of HBoV1 seems to be the major genotype in Iran.
The present day genetic architecture of a species bears much significance to its closely related species which is due to species-specific differences, shaped by different evolutionary forces across time scale. With the availability of whole genome sequence of several closely related species, it is now possible to infer evolutionary patterns of genes and genomes in specific lineages. To this respect, CD4 gene, primarily responsible for defensive mechanism in human, is conserved across a few taxa, and thus, comparative genomic studies could be useful for better understanding of host—pathogen biology. Comparative and evolutionary analyses were performed in eleven taxa (10 mammalian and avian) with different statistical algorithms. Phylogenetic inferences revealed recent divergence of human and chimpanzee, and pig was found to be diverged from rest of the taxa significantly. Additionally, gene length, microsatellites, and secondary structures were observed across taxa. The genetic architecture of CD4 gene and its evolutionary history in different mammalian taxa provide crucial evidence in support of the fact that this gene might have been evolving at a similar rate to other human immune system genes. Future population-based study and structural modeling would unravel the differential ability to interact with HIV virus and influence immune system in humans.
Authors:Csaba Ködmön, Judit Lukács, Niemann Stefan, Sándor Dávid, Imre Vadász and Ákos Somoskövy
Retrospektív tanulmányunkban, amely 2002-ben regisztrált 66 budapesti hajléktalantól származó
törzset ölel fel, egy helyi mikrojárványt igazoltunk Budapest legmagasabb tuberculosis-incidenciájú kerületében. A molekuláris genetikai vizsgálatok (IS
-RFLP DNS-ujjlenyomat, spoligotyping, mycobacterial interspred repetitive unit < MIRU > és
tipizálás) egy helyi eredetű, Budapest-specifikus
törzs jelenlétét igazolták. Ugyancsak figyelemre méltó a világszerte elterjedt, virulens Beijing-törzs hiánya. Eredményeink arra utalnak, hogy a hajléktalanok között a tuberculosis kontrolljára nagyobb figyelmet kell fordítani, és a megelőzés területén komolyabb lépésekre van szükség.
Authors:József Balla, György Balla, Béla Lakatos, Viktória Jeney and Klára Szentmihályi
A vas minden élő organizmus számára nélkülözhetetlen, ugyanakkor a fölöslegben lévő aktív vas veszélyes, hiszen szabad gyökök képződését katalizálhatja. Ezért a vas abszorpciója szigorúan szabályozott folyamat, melynek eredménye a vasvesztés és a vasfelvétel egyensúlya. Azokban az országokban, ahol az étkezéssel a hemvas bevitele jelentős, a szervezet vastartalmának nagy része hemből származik. A táplálékkal bevitt hemet a vékonybél enterocyta sejtjei intakt formában receptormediált módon abszorbeálják, majd hem-oxigenáz katalizálta reakcióban degradálják, így a vas transzferrinhez kötve hagyja el az enterocytát. A hem számos protein prosztetikus csoportja, így minden sejtünk szintetizálja. Mennyiségét tekintve a legjelentősebb hemprotein a hemoglobin, mely a vörösvértestekben az oxigén transzportját végzi. A vörösvértestek hemolízise során szabaddá váló hemoglobin specifikusan vagy aspecifikusan plazmaproteinekhez kötődik, és receptormediált úton felvételre kerül, majd degradálódik. A hemoglobinmolekula szerkezeti felépítése megnehezíti, de teljes mértékben nem akadályozza meg a hemoglobin (ferro) oxidációját methemoglobinná (ferri). A reakcióban szuperoxidgyök-anion is képződik, mely további szabad gyökös reakciókaszkádokat indít el. A képződött methemoglobin a hemet nem köti olyan szorosan, mint a hemoglobin, így az oxidáció következménye szabad hem képződése. A hem a plazmaprotein hemopexinhez kötődik, és receptormediált úton a sejtek által felvételre kerül, majd a hem-oxigenázok által katalizált reakcióban degradálódik. A hem ezenkívül a plazma lipoproteinjeihez, valamint az endothelium lipidmembránjához is kapcsolódhat, aminek következtében az LDL oxidálódik, illetve az endothelium oxidatív stresszre érzékenyebbé válik. A jelen összefoglaló célja a hemmel kapcsolatos folyamatok áttekintése.
Authors:Honglei Sun, Mei Qin, Yihong Xiao, Feng Yang, Wei Ni and Sidang Liu
An outbreak of simultaneously occurring haemangiomas, leiomyosarcoma and myeloma was observed in a commercial layer flock in China. The sick chickens were extremely thin and dehydrated. Scattered haemangiomas were found on the claws, breast and wings. At necropsy, haemangiomas and some other nodular tumours were also found in the internal organs. In addition, diffuse enlargement of the liver and spleen appeared in some birds. Histopathologically, haemangiomas were typically cavernous haemangiomas and haemangioendothelioma. In the diffusely swollen liver and spleen, multifocal or widespread marrow tumour cells filled with ball-like acidophilic particles in cytosol were observed, which are the characteristic pathological changes of avian myelocytomatosis. The nodular tumour cells formed by muscle bundles were of variable size, irregular shape, poorly differentiated and malaligned. Immunohistochemistry for vimentin, cytokeratin, actin (smooth muscle) and actin (sarcomeric) and Masson’s staining confirmed the different cell lineage of the nodular tumour, thus leading to the diagnosis of leiomyosarcoma. The seroprevalence of avian leukosis subgroup J (ALV-J) antibodies was 13.46% (7/52), while ALV-A/B and reticuloendotheliosis virus (REV) antibodies were not detectable. The DF-1 cells inoculated by virus extracted from liver samples from 24 infected chickens were cultured and the group-specific antigen (GSA) was identified by ELISA. All samples were positive for ALV, which was further identified as ALV-J by immunofluorescence assay (IFA). PCR analysis revealed that three isolates of ALV-J proviral sequence were close to the HPRS-103 prototype strain and other Chinese field strains isolated in recent years, while one isolate (DP01) had a lower homology with them. This is the first report that ALV-J infection caused the simultaneous occurrence of haemangiomas, leiomyosarcoma and myeloma in a commercial layer flock.
This is being hypothesised that the heterospory to begin with, might have originated within one specific sporangium thereafter separate male and female sporangia would have evolved in due course of time. This new category of a sporangium, is hereby named as “heterosporangium”, conceived to have been the cradle sporangium for the origin of heterospory. Such a sporangium may have possessed three types of spores, viz. microspores, megaspores and morphologically distinct spores possessing resemblances with spores of past lineages/fossils. Such a classical structure has been exemplified by a fundamental discovery of “intrasporangial heterospory” in 1968. This appears that this evolutionary phase could have followed the path of sequential evolution of isosporangium-anisosporangium-heterosporangium and finally, leading to “intersporangial heterospory” in the form of independent microsporangium and megasporangium. The independent sex differentiated sporangia must have had evolved by selective degeneration of spore mother cells in a differentiating young heterosporangium. In other words, a microsporangium should have evolved by the degeneration of megaspore mother cells and megasporangium by early degeneration of microspore mother cells. This selective degeneration must have been operative on account of some genetic mechanism as suggested by Bell in 1996 and later, demonstrated by our observations on epigenetic mechanisms suspecting mainly abrupt hypomethylation of DNA, to be responsible event as indicated in heterosporangia of Isoetes pantii Goswami et Arya. This paper exclusively establishes heterosporangium as a structure of rare evolutionary importance genetically inherent within the genome of the species observed consistently for more than five decades. Recent decline of such plants of I. × pantii does not lower down importance of heterosporangium because its physical presence can never be denied. The future of a species or an organ depends on operative modes of natural selection.
Plant community diversity is a major research focus in community ecology. The relationship between diversity patterns and different diversity indices is important for developing and improving biodiversity protection. In order to fully understand multi-dimensional diversity patterns of the subalpine meadow on Heyeping peak of Luya Mountain, we used a systematic sampling method and set 150 1 m × 1 m plots in June of 2018. Based on an analysis of the subalpine meadow community on Heyeping peak, we measured multiple diversity indices, carried out a correlation analysis between diversity and environmental factors, and compared correlations among different diversity indices. The goal was to clarify the ecological mechanisms and variation among various diversity indices and environmental factors. The main results were as follows: (1) The species diversity distribution was uniform, the taxonomic level was narrow, functional differences were small, and different pedigree structures were present in each plot. (2) A stable correlation between pedigree diversity index (PD) and species diversity index indicated niche conservativism; the net relatedness index (NRI) of community lineage structure was significantly correlated with the nearest species taxon index (NTI), species richness, and evenness index, indicating that plant community composition in the study area is mainly affected by habitat filtration. (3) The average taxonomic distinctness index (Λ+) and the average taxonomic distinctness index (Λ+) had a stable correlation; only the functional richness index (FRic) and Patrick species richness index were closely related. (4) Among the selected environmental factors, only the forest line had a stable correlation with species diversity index and PD and showed a negative correlation change, indicating an “edge effect” distribution of species diversity in the study area. In summary, the forest line was the key factor affecting the distribution of species diversity in the study area and the species relationships within the community. This work was supported by the National Natural Science Foundation of China (31400358).