Journal of Biological Research-Thessaloniki最新文献

Background: Mitochondria are fundamental organelles responsible for cellular metabolism and energy production in eukaryotes via the oxidative phosphorylation pathway. Mitochondrial DNA is often used in population and species studies with the assumption of neutral evolution. However, evidence of positive selection in mitochondrial coding genes of various animal species has accumulated suggesting that amino acid changes in mtDNA might be adaptive. The functional and physiological implications of the inferred positively selected sites are usually unknown and are only evaluated based on available structural and functional models. Such studies are absent in unicellular organisms that show several crucial differences to the electron transport chain of animal mitochondria. In the present study, we explored Eimeria mitogenomes for positive selection. We also tested for association between mtDNA polymorphism and environmental variation (i.e. host species), parasite life cycle (i.e. sporulation period), and efficient host cell invasion (i.e. pathogenicity, prepatent period).

Findings: We used site- and branch-site tests to estimate the extent of purifying and positive selection at each site and each lineage of several Eimeria parasite mitogenomes retrieved from GenBank. We founded sixteen codons in the three mtDNA-encoded proteins to be under positive selection compared to a strong purifying selection. Variation in the ratios of non-synonymous to synonymous changes of the studied parasites was associated with their different host species (F = 13.748; p < 0.001), whereas pathogenicity levels were associated with both synonymous and non-synonymous changes. This association was also confirmed by the multiple regression analysis.

Conclusions: Our results suggest that host species and pathogenicity are important factors that might shape mitochondrial variation in Eimeria parasites. This supports the important role of mtDNA variations in the evolution and adaptation of these parasites.

Background: Non-native species have aroused scientific interest because of their ability to successfully colonise areas to which they have been introduced, despite their sometimes limited genetic variation compared to their native range. These species establish themselves with the aid of some pre-existing features favouring them in the new environment. Pectinatella magnifica (Leidy, 1851), the freshwater magnificent bryozoan, is non-native in Europe and Asia. This study was designed to determine the genetic diversity and population structure of P. magnifica colonies collected from the Protected Landscape Area (PLA) and UNESCO Biosphere Reserve Třeboňsko (the Czech Republic) in the 2009 and 2011-2014 periods using Amplified Fragment Length Polymorphism (AFLP).

Findings: The vast majority of the examined non-native colonies, except three colonies sampled in 2012, expressed very low levels of genetic variation, not differentiating from the USA native colony. The Bayesian clustering approach grouped the 28 accessions into two genetically different populations.

Conclusions: The data suggest relatively low gene diversity within all colonies, which might reflect the recent expansion of P. magnifica in the Czech Republic.

Background: Minimizing the effects of transportation on the properties of biological material is a major challenge for the scientific community. The viability of cells is important in cases where their study is urgent for evaluation of treatment response or for the study of cancer progression. Circulating tumor cells (CTCs) constitute a cell subpopulation with great importance for oncologists, because of their prognostic value. Detection and isolation of CTCs from blood samples is a routine activity in many laboratories, but concerns exist with regard to the maintenance of the cells during transportation. In this study, experiments were conducted to determine the stability of gene and protein expression in CTCs over a period of 96 h.

Results: Blood samples collected from healthy individuals and patients with cancer were each divided into five aliquots, which were stored at 2-8 °C and analyzed after 0, 24, 48, 72 and 96 h of storage. CTCs from patients and CD45-negative cells from healthy individuals were isolated each day using enrichment protocols, and qPCR was performed to determine expression levels of genes encoding specific biological markers. In addition, cells from breast and colon cancer cell lines were spiked into blood samples from healthy individuals, and these samples were stored and analyzed over a period of 96 h by PCR and by flow cytometry. The markers that were studied included housekeeping genes and genes associated with the response to chemotherapy, as well as genes encoding transcription factors. The results demonstrated that the expression profiles of specific genes and proteins in CTCs were not significantly affected by 72 h of storage. After 96 h of storage, expression of some genes was altered.

Conclusion: The transportation of blood at low temperature (2-8 °C) in the presence of the anticoagulant EDTA can protect CTCs from alteration of gene and protein expression for at least 72 h. Furthermore, under these conditions, CTCs can be detected and isolated 96 h after blood collection.

Background: Altered microRNAs expression mediates tumor development and progression in many type cancers including triple negative breast cancer (TNBC). Here we detected the effect of miR-454 on cell proliferation, migration and invasion of triple negative breast cancer cells.

Results: miR-454 promoted the proliferation of TNBC, and enhanced migration and invasion in TNBC cells. Meanwhile, miR-454 improved the survival of TNBC cells after ironizing radiation. miR-454 inhibited radiation-induced apoptosis in TNBC cells by regulation of caspase 3/7 and Bcl-2 expression. Furthermore, PTEN and pAKT levels in TNBC cells were changed after overexpression of miR-454.

Conclusions: miR-454 played an essential role in tumor development and progression in TNBC, and might be used as a potential biomarker to predict radiotherapy response and prognosis in TNBC.

Background: In calvarial mice, mesenchymal stem cells (MSCs) differentiate into osteoprogenitor cells and then differentiate into osteoblasts that differentiate into osteocytes, which become embedded within the bone matrix. In this case, the cells participating in bone formation include MSCs, osteoprogenitor cells, osteoblasts and osteocytes. The calvariae of C57BL/KaLwRijHsD mice consist of the following five bones: two frontal bones, two parietal bones and one interparietal bone. This study aimed to analyse some bone marker genes and bone related genes to determine whether these calvarial bones have different bone microenvironments.

Methods: C57BL/KaLwRijHsD calvariae were carefully excised from five male mice that were 4-6 weeks of age. Frontal, parietal, and interparietal bones were dissected to determine the bone microenvironment in calvariae. Haematoxylin and eosin staining was used to determine the morphology of different calvarial bones under microscopy. TaqMan was used to analyse the relative expression of Runx2, OC, OSX, RANK, RANKL, OPG, N-cadherin, E-cadherin, FGF2 and FGFR1 genes in different parts of the calvariae.

Results: Histological analysis demonstrated different bone marrow (BM) areas between the different parts of the calvariae. The data show that parietal bones have the smallest BM area compared to frontal and interparietal bones. TaqMan data show a significant increase in the expression level of Runx2, OC, OSX, RANKL, OPG, FGF2 and FGFR1 genes in the parietal bones compared with the frontal and interparietal bones of calvariae.

Conclusion: This study provides evidence that different calvarial bones, frontal, parietal and interparietal, contain different bone microenvironments.

Background: Alpha 1-antitrypsin (α1-AT) may affect the susceptibility of mastitis in dairy cattle for its possible role in the protection of lactoferrin from proteolytic degradation in the mammary. Milk somatic cell score (SCS) is a logarithmic transformation of the milk somatic cell count widely used as an index to evaluate mastitis. To study the relationships of α1-AT gene and SCS in Chinese Holstein cows, methods of PCR-SSCP, DNA sequencing, PCR-RFLP, and CRS-PCR technologies were used to detect single nucleotide polymorphisms sites in α1-AT gene.

Results: Two polymorphic sites at G5503A and G5746C of α1-AT gene were found. AA (0.3633), AB (0.4644) and BB (0.1723) genotypes were detected at G5503A site, CC (0.3483), CD (0.4906) and DD (0.1611) genotypes were found at G5746C in Chinese Holstein cows. Least squares mean of SCS for individuals with BB genotype was significantly lower than that with AA and AB genotype (p < 0.01), and that with AB genotype was significantly lower than that with AA (p < 0.05). There was no significant difference among individuals with CC, CD and DD genotypes (p > 0.05). Least squares mean of SCS for individuals with BBDD genotype combination were significantly lower than those with AACC and AACD (p < 0.05).

Conclusions: Statistical analysis indicated that B allele and BBDD genotype combination of α1-AT can improve mastitis resistance in dairy cattle.

Positive selection occurs when an allele is favored by natural selection. The frequency of the favored allele increases in the population and due to genetic hitchhiking the neighboring linked variation diminishes, creating so-called selective sweeps. Detecting traces of positive selection in genomes is achieved by searching for signatures introduced by selective sweeps, such as regions of reduced variation, a specific shift of the site frequency spectrum, and particular LD patterns in the region. A variety of methods and tools can be used for detecting sweeps, ranging from simple implementations that compute summary statistics such as Tajima's D, to more advanced statistical approaches that use combinations of statistics, maximum likelihood, machine learning etc. In this survey, we present and discuss summary statistics and software tools, and classify them based on the selective sweep signature they detect, i.e., SFS-based vs. LD-based, as well as their capacity to analyze whole genomes or just subgenomic regions. Additionally, we summarize the results of comparisons among four open-source software releases (SweeD, SweepFinder, SweepFinder2, and OmegaPlus) regarding sensitivity, specificity, and execution times. In equilibrium neutral models or mild bottlenecks, both SFS- and LD-based methods are able to detect selective sweeps accurately. Methods and tools that rely on LD exhibit higher true positive rates than SFS-based ones under the model of a single sweep or recurrent hitchhiking. However, their false positive rate is elevated when a misspecified demographic model is used to represent the null hypothesis. When the correct (or similar to the correct) demographic model is used instead, the false positive rates are considerably reduced. The accuracy of detecting the true target of selection is decreased in bottleneck scenarios. In terms of execution time, LD-based methods are typically faster than SFS-based methods, due to the nature of required arithmetic.

The pathophysiological mechanisms which lead to sudden infant death syndrome (SIDS) are not completely understood. Cardiac channelopathies are a well-established causative factor with long QT syndrome (LQTS) being the most frequent one, accounting for approximately 12% of SIDS cases. The genetic substrate of the above arrhythmogenic syndrome has been thoroughly described but only specific gene mutations or polymorphisms have been identified as SIDS causative. The review will focus on the prevalence of LQTS-induced SIDS or near-SIDS cases and the mutations held responsible. A literature search was performed in PubMed and Scopus electronic databases. Search terms used were: long QT syndrome, channelopathies, QT prolongation, cardiac ion channels. The above-mentioned search terms were always combined with the term: sudden infant death syndrome. Study types considered eligible were: case-control, family pedigree analysis, case reports. The prevalence of LQTS-induced SIDS according to six broad genetic studies ranges from 3.9 to 20.6%, with an average of 12%. Since LQTS can be effectively managed, LQTS-related SIDS cases could be prevented, provided that a screening method is efficient enough to detect all the affected infants.

Background: Gamma (γ) ray, an electromagnetic radiation, is occasionally accompanying the emission of an alpha or beta particle. Exposure to such radiation can cause cellular changes such as mutations, chromosome aberration and cellular damage which depend upon the total amount of energy, duration of exposure and the dose. Ionizing radiation can impair spermatogenesis and can cause mutations in germ cells. In general, type B spermatogonia are sensitive to this type of radiation. The current study was carried out to evaluate the protective role of hesperidin (H), as a polyphenolic compound, on rat testis injury induced by γ-radiation.

Methods: Rats were divided into groups including C group (control rats), R (irradiated) group (rats irradiated with γ-radiation), Vehicle (V) group (rats administered with dimethylsulfoxide "DMSO"), H group (rats administered with H only), HR and RH groups (rats treated with H before and after exposure to γ-radiation, respectively). Malondialdehyde (MDA: the end product of lipid peroxidation "LPO") and xanthine oxidase (XO: it generates reactive oxygen species "ROS") in testes homogenate as well as nitric oxide (NO: as ROS) in mitochondrial matrix were determined. The apoptotic markers including DNA-fragmentation (DNAF) in testes homogenate and calcium ions (Ca²⁺) in mitochondrial matrix were determined. Superoxide dismutase (SOD) and catalase (CAT) activities in testes homogenate, while reduced glutathione "GSH" in nuclear matrix were determined. Also histopathological examination for testes tissues through electron microscope was studied.

Results: Exposure of rats to γ-radiation (R group) increased the levels of MDA, NO, DNAF, Ca²⁺ and XO activity, while it decreased GSH level, SOD and CAT activities as compared to the C groups; γ-radiation increased oxidative stress (OS), LPO, apoptosis and induced testes injuries. These results are in agreement with the histopathological examination. In contrast, treatment with H before or after exposure to γ-radiation (HR and RH groups, respectively) decreased the levels of MDA, NO, DNAF and Ca²⁺ but increased GSH level and the activities of SOD, CAT and XO as compared to R group and this indicates that H decreased OS, LPO and apoptosis. Also, the histopathological results showed that H improved testis architecture and this is related to the antioxidant and anti-apoptotic activities of H contents. Protection is more effective when H is given before rather than after exposure. Finally, administration of H to healthy rats for a short period had no adverse affect on testes cells.

Conclusion: Hesperidin showed antioxidant and anti-apoptotic activities. It has a protective role against OS, injury and apoptosis induced by γ-radiation in testes. Protection is more effective when H is given before rather than after exposure.Graphical Abstract.

The Aegean archipelago, comprising numerous islands and islets with great heterogeneity in topographic, geological, historical and environmental properties, offers an ideal natural laboratory for ecological and evolutionary research, and has been the stage for a very long interaction between human civilizations and local ecosystems. This work presents insights that have been gained from past and current relevant research in the area, highlighting also the importance of the Aegean archipelago as a useful model to address many major questions in biogeography, ecology and evolutionary processes. Among the most interesting findings from such studies concern the role of habitat heterogeneity as the most important determinant of species richness, the development of a new model (Choros) for the species-area-habitats relationship, the mechanistic aspects of the Small Island Effect, the very high rates of species turnover, the lack of a role for interspecific competition in shaping species co-occurrence patterns in most cases, the importance of non adaptive radiation in diversification of several taxa, the insights into the relative roles of vicariance and dispersal in speciation, the understanding of the interplay between human presence and the establishment of exotic species and extinction of indigenous biotas. Concluding, the Aegean archipelago is an ideal stage for research in evolution, ecology and biogeography, and has the potential to become a model study area at a global level, especially for land-bridge, continental islands.