A Regulatory Role for NBS1 in Strand-Specific Mutagenesis during Somatic Hypermutation

Activation-induced cytidine deaminase (AID) is believed to initiate somatic hypermutation (SHM) by deamination of deoxycytidines to deoxyuridines within the immunoglobulin variable regions genes. The deaminated bases can subsequently be replicated over, processed by base excision repair or mismatch repair, leading to introduction of different types of point mutations (G/C transitions, G/C transversions and A/T mutations). It is evident that the base excision repair pathway is largely dependent on uracil-DNA glycosylase (UNG) through its uracil excision activity. It is not known, however, which endonuclease acts in the step immediately downstream of UNG, i.e. that cleaves at the abasic sites generated by the latter. Two candidates have been proposed, an apurinic/apyrimidinic endonuclease (APE) and the Mre11-Rad50-NBS1 complex. The latter is intriguing as this might explain how the mutagenic pathway is primed during SHM. We have investigated the latter possibility by studying the in vivo SHM pattern in B cells from ataxia-telangiectasia-like disorder (Mre11 deficient) and Nijmegen breakage syndrome (NBS1 deficient) patients. Our results show that, although the pattern of mutations in the variable heavy chain (VH) genes was altered in NBS1 deficient patients, with a significantly increased number of G (but not C) transversions occurring in the SHM and/or AID targeting hotspots, the general pattern of mutations in the VH genes in Mre11 deficient patients was only slightly altered, with an increased frequency of A to C transversions. The Mre11-Rad50-NBS1 complex is thus unlikely to be the major nuclease involved in cleavage of the abasic sites during SHM, whereas NBS1 might have a specific role in regulating the strand-biased repair during phase Ib mutagenesis

Balkan aufgetischt. Entwicklung einer Rezeptsammlung für die Stufe Sek I mit Rezepten aus Südosteuropa und Untersuchung der Auswirkungen auf die Lernfreude im Hauswirtschaftsunterricht

Der bisherige Forschungsstand liefert keine experimentellen Studien, welche die Lernfreude von Schülerinnen und Schülern im Hauwirtschaftsunterricht im Zusammenhang mit Arbeitsmaterialen aus anderen Kulturkreisen untersucht. Diese Defizite sollen in der hier berichteten Studie in erster Annäherung bearbeitet werden. Im Zentrum stand die Frage, ob v.a. Schülerinnen und Schüler mit Migrationshintergrund sich besser angesprochen fühlen, wenn die Nahrungszubereitung mit Rezepten aus ihrem Kulturkreis vermittelt wird. Die Datenanalyse der Vergleichsstudie basierte auf einer Stichprobe von insgesamt 32 Lernenden (22 in der Interventionsgruppe und 10 in der Kontrollgruppe) der zweiten Sekundarstufe. Die Veränderung der Lernfreude wurde anhand eines Fragebogens ermittelt, welcher als Vor- und Nachtest diente. Die Ergebnisse zeigen, dass es signifikante Beziehung zwischen Lernfreude und Gebrauch von südosteuropäischen Rezepten im Hauswirtschaftsunterricht gibt. Mit diesem Ergebnis bestätigt die Studie, was in vielen Forschungen bereits dargelegt wurde: Das Einsetzen von Unterrichtsmaterialen, welche auf die Interessen, Vorkenntnisse und persönlichen Hintergründe der Schülerinnen und Schüler basieren, kann zur Steigerung derer Lernfreude führen. Als Produkt dieser Arbeit entstand eine Rezeptsammlung mit alltäglichen Rezepten aus Südosteuropa, welche an Schulen als Erweiterung zu den bereits bestehenden Rezepten des Schulkochbuchs Tiptopf verwendet werden kann

Primena testova vegetativne kompatibilnosti za identifikaciju biodiverziteta fitopatogenih gljiva

Visual assessment of phenotypes, performed when two strains of one fungal species are cultivated in a mixed culture on specific media, is known as vegetative or heterokaryotic compatibility or incompatibility test, which enables identification of fungal clones and their classification based on phylogenetic groups. Hyphae of strains that have identical alleles at all vic loci can anastomose into a form of a visible heterokaryon. Strains that divide compatible loci and can anastomose each other belong to a subpopulation termed the vegetative compatibility group (VCG), which is genetically distinguishable from other VCGs. Each VCG is specific regarding its host plant or related host groups and can, but does not have to be virulent on other hosts. Vegetative compatibility can be established in different ways, but complementary auxotrophic strains or strains formed by spontaneous mutation during nutrition, capable of forming a prototrophic heterokaryon are predominantly used. The nit mutants are considered excellent genetic markers for determination of vegetative compatibility and grouping of strains or clones of one fungus into the same or different VCGs. The ability only to determine whether strains are the same or not, but not the degree of their relatedness using VCG, is a limiting factor in analyses that could be performed. VCGs are the most efficient when they are employed to detect the presence of a specific strain in a population. This paper provides an overview of the importance of the phenomenon of vegetative compatibility. Vegetative compatibility is one of the most important genetic traits in ascomycetes by which one subpopulation can be identified as a distinct genetic group. Furthermore, the procedures for isolation, identification and determination of nit mutant phenotypes, and for identification of complementary strains and VCGs are described in detail.Vizuelna ocena fenotipa koja se izvodi kada se dva izolata ili soja jedne vrste gljive gaje u združenim kulturama na specifičnim podlogama, poznata kao test vegetativne ili heterokarionske kompatibilnosti ili nekompatibilnosti, omogućava identifikaciju klonova gljive i njihovu klasifikaciju prema filogenetskim grupama. Hife izolata koje imaju identične alele kod svih vic lokusa mogu da anastomoziraju u oblik vidljivog heterokariona. Izolati koji dele kompatibilne lokuse i mogu da anastomoziraju jedni s drugima pripadaju subpopulaciji označenoj kao vegetativno kompatibilna grupa (VCG) koja je genetski odvojena od drugih vegetativno kompatibilnih grupa (VCGs). Svaka VCG je specifična prema biljci domaćinu ili srodnoj grupi domaćina i može ili ne mora biti virulentna na drugim domaćinima. Vegetativna kompatibilnost može biti utvrđena na različite načine, ali se najčešće koriste komplementarni auksotrofni sojevi, ili sojevi koji su nastali spontanom mutacijom tokom ishrane, a koji su sposobni da obrazuju prototrofni heterokarion. Smatra se da su nit mutanti izvrsni genetički markeri za utvrđivanje vegetativne kompatibilnosti i grupisanje sojeva ili klonova jedne vrste gljive u iste ili različite VCGs. Nesposobnost da se odredi stepen srodnosti korišćenjem VCGs, već samo da li su izolati isti ili ne, ograničava tipove analiza koje bi mogle biti postavljene. VCGs su najefikasnije kada se koriste za utvrđivanje prisustva specifičnog soja u populaciji. U radu je dat pregled značaja fenomena vegetativne kompatibilnosti, kao jedne veoma značajne genetičke osobine kod askomiceta kojom se jedna subpopulacija može identifikovati kao posebna genetička grupa. Isto tako, dat je detaljan opis postupka za izolaciju, identifikaciju i utvrđivanje fenotipa nit mutanata, kao i za identifikaciju komplementarnih sojeva i VCGs

Further insight into the bioactivity of the freshwater sponge Ochridaspongia rotunda

Context: Bioprospection has become a dynamic scientific field that explores novel possibilities for the implementation of natural products in medicine and pharmacy. Compared to marine species from all kingdoms, freshwater species have been highly neglected. Objective: This work focuses on the screening of acetylcholinesterase inhibitory (AChE) and mutagenic activities of the acetone extract (obtained by maceration) of the freshwater sponge Ochridaspongia rotunda Arndt (Malawispongiidae) in vitro. Materials and methods: AChE inhibitory activity was evaluated both in liquid (five different concentrations of the extract, from 1 to 100 μg/mL) and in solid (seven different concentrations of the extract, from 0.5 to 10.0 μg) by methods well described in literature, while mutagenicity was estimated using the Ames test (four different concentrations of the extract, from 0.106 to 1.328 mg/plate). Results: Ochridaspongia rotunda acetone extract exhibited promising AChE inhibitory activity in a dose-dependent manner both in liquid (IC50 23.07 μg/mL) and in solid (1.50 μg). Furthermore, the Ames test revealed no sign of mutagenicity at any concentration tested. Its FTIR spectrum coupled with the positive Liebermann?Burchard, Salkowski and Zak color reactions (tests) indicated the presence of sterol compounds. Discussion and conclusion: The screened extract may inspire a search for novel anticholinesterase therapeutic agent(s) potentially used in the treatment of Alzheimer's disease. Further research will be directed toward its detailed chemical analysis along with addressing the issue of a real producer of the natural product(s) responsible for the AChE activity observed

MEDIASTINAL MASS AS A PROGNOSTIC FACTOR OF HODGKIN LYMPHOMA – CASE REVIEW

Many studies have researched the prognostic factors of Hodgkin disease. Up date, seven most important prognostic factors have been defined.Among them, as an important negative prognostic factor, the dissemination of the disease at the moment of diagnosis stands out. The aim of this study was to determine the influence of the presence of mediastinal mass greater than a third of the chest diameter in Hodgkin lymphoma on the disease outcome. In this study, an 18-year-old patient P.A. was presented. At the time of diagnosis, the patient had Bulky disease. Mediastinal mass was observed by radiography, computed tomography, ultrasound of the heart.The patient was treated with ABVD, GDP, BEACOPP, miniBEAM protocol and mediastinal radiation. In this patient, the mediastinal mass persisted in spite of the therapy.The course of disease deteriorated due to the presence of resistant pericardial effusion, and the patient died three years after

Antifungal activity of selected essential oils against fungi isolated from medicinal plant

The development of protective products with natural origin as alternatives to synthetic fungicides is currently in the spotlight. Qualitative and quantitative chemical analysis of 16 selected essential oils was determined. Then, antifungal properties determined by in vitro microdilution method against 21 fungi isolated from herbal drugs were evaluated. All tested oils showed some antifungal activity against all fungi used. Savory, thyme and oregano oils, characterized by the presence of phenol such as carvacrol and thymol, and rose oil containing mainly monoterpene alcohols (citronellol and geraniol) proved to be the most effective inhibitor of all fungi tested. Also, combination of particular oils showed reduction of the MIC values when combined, commendatory mixtures for potential application in practice. Moreover, the reduction of the total number of fungi, in situ, using selected essential oils was determined. (C) 2014 Elsevier B.V. All rights reserved.Ministry of Education, Science and Technological Development, Republic of Serbia {[}46013, 173026

A contribution to pharmaceutical biology of freshwater sponges

<p><i>In vitro</i> anti-tumour and anti-radical activities of the acetone extract of the freshwater sponge <i>Ochridaspongia rotunda</i> were the subject of this study. The extract was found to be highly cytotoxic to human lung tumour cell line A-549 reaching IC₅₀ value of 5.01 ± 0.21 μg/mL. Indeed, it displayed only 2-fold less anti-tumour activity than doxorubicin (IC₅₀ value 2.42 ± 0.13 μg/mL) used as a positive control. The same extract was also found to be almost 37-fold more selective against A-549 vs. MRC-5 (normal) lung cells, in difference to weak selectivity of doxorubicin (less than 3-fold). Its profound anti-DPPH radical activity comparable to that of quercetin (IC₅₀ values 3.68 ± 0.19 and 3.14 ± 0.09 μg/mL, respectively) coupled with no signs of genotoxicity in the comet assay (MRC-5 cell line, vs. doxorubicin) has actually implicated the importance of this animal bioresource in searching for pharmaceutically useful bioactive compounds of natural origin.</p

Genotyping Of Bacillus Spp. Isolate Collection From Natural Samples

The aim of this study was genotyping and identification of collection of 164 Bacillus spp. isolates, from samples of soil, manure, and straw gathered from across Serbia, using Pulse field gel electrophoresis (PFGE) combined with sequencing of tuf gene, one of the housekeeping genes. The PFGE analysis with NotI enzyme was used to determine phylogenetic relationships of isolates and referent strains. Four large groups of Bacillus spp. were distinguishable: cereus, subtilis, pumilus and megaterium and within enormous genetic diversity. Bacillus subtilis Marburg referent strain did not group with rest of the strains from the subtilis group (Bacillus subtilis ATCC6633 and Bacillus atrophaeus ATCC9372). Strains from the cereus group were distinguished and closely grouped together. One representative isolate from each of 21 distinct PFGE groups was identified by sequencing of tuf gene. Eight different species were identified among chosen isolates: B. amyloliquefaciens, B. subtilis, B. pumilus, B. safensis, B. megaterium, B. cereus, B. anthracis and B. thuringiensis. Our results showed that PFGE analysis combined with sequencing of one of the housekeeping genes could be used for characterization of large collections of Bacillus isolates. The determination of tuf gene recommended itself to be an adequate and sufficient analysis for obtaining very clear and unambiguous results, with high resolution of separation of Bacillus species