Cytogenetics of the Hybridogenetic Frog Pelophylax grafi and Its Parental Species Pelophylax perezi.

Hybrid taxa from the genus Pelophylax can propagate themselves in a modified way of sexual reproduction called hybridogenesis ensuring the formation of clonal gametes containing the genome of only one parental (host) species. Pelophylax grafi from South-Western Europe is a hybrid composed of P. ridibundus and P. perezi genomes and it lives with a host species P. perezi (P-G system). Yet it is unknown, whether non-Mendelian inheritance is fully maintained in such populations. In this study, we characterize P. perezi and P. grafi somatic karyotypes by using comparative genomic hybridization, genomic in situ hybridization, fluorescent in situ hybridization, and actinomycin D-DAPI. Here, we show the homeology of P. perezi and P. grafi somatic karyotypes to other Pelophylax taxa with 2n = 26 and equal contribution of ridibundus and perezi chromosomes in P. grafi which supports F1 hybrid genome constitution as well as a hemiclonal genome inheritance. We show that ridibundus chromosomes have larger regions of interstitial (TTAGGG)n repeats flanking the nucleolus organizing region on chromosome no. 10 and a high quantity of AT pairs in the centromeric regions. In P. perezi, we found species-specific sequences in metaphase chromosomes and marker structures in lampbrush chromosomes. Pericentromeric RrS1 repeat sequence was present in perezi and ridibundus chromosomes, but the blocks were stronger in ridibundus. Various cytogenetic techniques applied to the P-G system provide genome discrimination between ridibundus and perezi chromosomal sets. They could be used in studies of germ-line cells to explain patterns of clonal gametogenesis in P. grafi and broaden the knowledge about reproductive strategies in hybrid animals.

Genome elimination from the germline cells in diploid and triploid male water frogs Pelophylax esculentus.

Hybridogenesis is a hemiclonal reproductive strategy in diploid and triploid hybrids. Our study model is a frog P. esculentus (diploid RL and triploids RLL and RRL), a natural hybrid between P. lessonae (LL) and P. ridibundus (RR). Hybridogenesis relies on elimination of one genome (L or R) from gonocytes (G) in tadpole gonads during prespermatogenesis, but not from spermatogonial stem cells (SSCs) in adults. Here we provide the first comprehensive study of testis morphology combined with chromosome composition in the full spectrum of spermatogenic cells. Using genomic in situ hybridization (GISH) and FISH we determined genomes in metaphase plates and interphase nuclei in Gs and SSCs. We traced genomic composition of SSCs, spermatocytes and spermatozoa in individual adult males that were crossed with females of the parental species and gave progeny. Degenerating gonocytes (24%-39%) and SSCs (18%-20%) led to partial sterility of juvenile and adult gonads. We conclude that elimination and endoreplication not properly completed during prespermatogenesis may be halted when gonocytes become dormant in juveniles. After resumption of mitotic divisions by SSCs in adults, these 20% of cells with successful genome elimination and endoreplication continue spermatogenesis, while in about 80% spermatogenesis is deficient. Majority of abnormal cells are eliminated by cell death, however some of them give rise to aneuploid spermatocytes and spermatozoa which shows that hybridogenesis is a wasteful process.

Maintenance of pure hybridogenetic water frog populations: Genotypic variability in progeny of diploid and triploid parents.

An intriguing outcome of hybridisation is the emergence of clonally and hemiclonally reproducing hybrids, that can sustain, reproduce, and lead to the emergence of polyploid forms. However, the maintenance of diploid and polyploid hybrid complexes in natural populations remains unresolved. We selected water frogs from the Pelophylax esculentus complex to study how diploid and triploid hybrids, which reproduce hemiclonally via hybridogenesis, are maintained in natural populations. During gametogenesis in diploid hybrids, one of the parental genomes is eliminated, and the remaining genome is endoreplicated. In triploid hybrids, the single-copy genome is typically eliminated, while genome endoreplication does not occur. To investigate how diploid and triploid hybrid frogs reproduce in populations without parental species, we crossed these hybrid animals from two separate pure hybrid populations located in Poland. Using cytogenetic analysis of tadpoles that emerged from the crosses, we established which gametes were produced by parental hybrids. The majority of hybrid females and hybrid males produced one type of gamete with the P. ridibundus genome. However, in both studied populations, approximately half of the diploid and triploid hybrids simultaneously produced gametes with different genome compositions and ploidy levels, specifically, the P. ridibundus and P. lessonae genomes, as well as diploid gametes with genomes of both parental species. Triploid hybrid males and females mostly produced haploid gametes with the P. lessonae genome; however, gametes with the P. ridibundus genome have also been observed. These results suggest that not all hybrids follow the classical hybridogenetic reproduction program and reveal a significant level of alterations in the gametogenesis pathways. In addition, we found a variable survival rate of particular progeny genotypes when we crossed hybrid females with different males suggesting the important role of postzygotic barriers on the maintenance of pure hybrid systems. We suggest that the observed variability in produced gametes and the different survival rate of the progeny with certain genotypes is crucial for the existence of pure hybrid systems.

Influence of Angiotensin II on cell viability and apoptosis in rat renal proximal tubular epithelial cells in in vitro studies.

INTRODUCTION: Angiotensin II (Ang II) is multifunctional peptide that plays an important role in blood pressure regulation and maintenance electrolyte homeostasis. It shows biological effects by activating two main receptors: AT1 and AT2. The aim of the present work was to investigate the effect of Ang II on NRK-52E cells in in vitro studies. Furthermore, an attempt was made to determine the effectiveness of the AT1 and AT2 receptor blocker activity (respectively, losartan and PD123319). METHODS: The study was carried out using adherent NRK-52E cell line. Immunofluorescence and Western Blot method were used to confirm the presence of AT1 and AT2 receptors in the cells. The SRB and MTT tests showed decrease in the viability of NRK-52E cells incubated with Ang II in comparison to the control (without Ang II). RESULTS: The blockade of the AT1 receptor caused an increase in cell viability in comparison to cells incubated with Ang II only. The blockade of AT2 receptor also triggered statistically significant increase in cell viability in comparison with cells only exposed to Ang II. Combined administration of blockers for both receptors (losartan and PD123319) decreased Ang II cytotoxicity against NRK-52E cell line. The apoptosis was only observed in cells incubated with Ang II in comparison with control cells. However, simultaneous use of both blockers caused statistically significant decrease in apoptosis. CONCLUSIONS: The result of our study indicates that Ang II causes damaging effect on NRK-52E cells by directing them to programmed cell death. It seems that not only does the AT2 receptor itself play an important role in the induction of apoptosis, but also its interaction with AT1 receptor does as well.

Liver volume: a point of no return in liver transplantation?

INTRODUCTION: In patients with cirrhosis, only a 75% liver volume (LV) is expected compared with age­matched healthy individuals. Changes in LV might be an indicator of therapeutic effectiveness or disease progression. OBJECTIVES: To establish whether LV is a prognostic factor in chronic liver disease irrespective of etiology and LV impacts the outcomes of liver transplant (LT). PATIENTS AND METHODS: In total, 135 consecutive LT recipients were prospectively included in this study: 38 women and 97 men. The median (minimum-maximum) age was 51 (21-70) years; body mass index (BMI), 27.3 (17.3-39.2) kg/m2; Child-Pugh class (CPC), C; Model of End­Stage Liver Disease (MELD), 16 (7-47) points; and the third lumbar vertebra skeletal muscle index (L3SMI), 47.7 (19.7-73.4) cm2/m2. Liver volume and L3SMI were calculated based on computed tomography scans at listing for LT. The receiver operating characteristic (ROC) curve was analyzed to determine the accuracy of LV in mortality prediction after LT. RESULTS: Liver volume differed significantly among patients in terms of chronic liver disease etiology, with the lowest values noted in those with hepatitis C virus infection. Liver volume was neither a prognostic factor of disease progression and need for LT with respect to the CPC and MELD scores nor correlated with BMI and L3SMI (P >0.05). The area under the ROC curve of LV in mortality prediction was 0.573 (95% CI, 0.403-0.743). Liver volume smaller than the median tended to be positively associated with the risk of prolonged intensive care unit stay and death (P = 0.057 and P = 0.058, respectively). CONCLUSIONS: Low liver volume did not seem be a point of no return in LT candidates.

Effects of Long-Term High-Fat Diet and Its Reversal on Lipids and Lipoproteins Composition in Thoracic Duct Lymph in Pigs.

BACKGROUND This study was carried out to evaluate the effects of a long-term high-fat diet on lipids and lipoproteins composition in thoracic duct lymph in pigs. MATERIAL AND METHODS We examined lymph taken from the thoracic duct from 24 female white sharp-ear pigs, divided into 3 experimental groups fed different diets for 12 months: (a) the control group, fed the standard balanced diet; (b) the HFD group, fed an unbalanced, high-fat diet, and (c) the reversal diet group (RD), fed an unbalanced, high-fat diet for 9 months and then a standard balanced diet for 3 months. RESULTS Lymph analysis after 12 months of fixed diets revealed significantly higher concentration of proteins in the HFD group in comparison to the control and RD groups. Examination of lymph lipoproteins fractions showed that the high-fat diet in the HFD group in comparison to control group caused an increase in cholesterol, phospholipids, and proteins content within HDL and chylomicrons. There were also more proteins within HDL in the HFD group in comparison to the RD group and more triglycerides within chylomicrons in the HFD group in comparison to the control group. CONCLUSIONS A long-term high-fat diet resulted in changed structure of HDL and chylomicrons in the thoracic duct lymph. Alterations in HDL composition suggest that a high-fat diet enhances reverses cholesterol transport. Changes in chylomicrons structure show the adaptation to more intense transport of dietary fat from the intestine to the liver under the influence of a high-fat diet. Reversal to a standard balanced diet had the opposite effects.

The effects of interior design on wellness - Eye tracking analysis in determining emotional experience of architectural space. A survey on a group of volunteers from the Lublin Region, Eastern Poland.

INTRODUCTION AND OBJECTIVE: Using the concepts of Ulrich's theory of supportive design and Malkin's healing environment, an eye tracking experiment was designed in order to measure respondents' reactions while looking at visualisations of various interiors, with the aim of verifying whether certain parameters of an interior are related to emotional reactions in terms of positive stimulation, and the sense of security and comfort. MATERIAL AND METHODS: 12 boards were designed, incorporating standard features of an interior, i.e. (1) proportions, (2) lighting, (3) colour scheme of a room, as well as (4) the colours and spatial arrangement of furnishings. Respondents' reactions were recorded with an eye tracker Tobii TX300 and supplemented by self-descriptions of emotional reactions. RESULTS: The results showed that the varying spatial and colour arrangements presented in the interior visualisations provoked different emotional responses, confirmed by pupil reaction parameters, as measured by the eye tracking device. CONCLUSIONS: Architectural space can have a diverse emotional significance and impact on an individual's emotional state. This is an important conclusion from the point of view of optimising and creating the so-called supportive and healing environment. The results have implications for the interpretation of the pupil diameter as an index of emotional reactions to different architectural space visualisations. Testing the eye tracker as a method helpful in diagnosing the emotional reactions to features of the interior is justified, and can provide an effective tool for early diagnosis of the impact of architectural space on the well-being of individuals. It can also be a good form of testing the emotional significance of architectural designs before they are implemented.

Correction to: Xenopus LAP2ß protein knockdown affects location of Lamin B and nucleoporins and has effect on assembly of cell nucleus and cell viability.

The original publication of this paper contains a mistake.

The programmed DNA elimination and formation of micronuclei in germ line cells of the natural hybridogenetic water frog Pelophylax esculentus.

DNA elimination is a radical form of gene silencing and occurs both in somatic and germ cells. The programmed DNA elimination occurs during gametogenesis in interspecies hybrids that reproduce by hybridogenesis (stick insects, fishes, and amphibians) and concerns removal of whole genomes of one of the parental species and production of clonal gametes propagating the genome of the other species. The cellular mechanisms differ considerably in hybridogenetic insects and fishes but remains unknown in edible frogs Pelophylax esculentus, natural hybrids between Pelophylax lessonae and Pelophylax ridibundus. Here we report DNA elimination mechanism in early developing gonads of diploid and triploid hybrid frogs, studied by TEM, immunofluorescence, and cytochemistry. In gonocytes of both sexes (primary oogonia and prespermatogonia), micronuclei emerge as detached nuclear buds formed during interphase. We found depletion of nuclear pore complexes in micronuclear membrane and chromatin inactivation via heterochromatinization followed by degradation of micronuclei by autophagy. Micronuclei formation does not lead to apoptotic cell death showing that genome elimination is a physiological process. Chromatin elimination via micronuclei in P. esculentus is unique among hybridogenetic animals and contributes to broadening the knowledge about reproductive modes in animals.

Correlation between levels of expression of minichromosome maintenance proteins, Ki-67 proliferation antigen and metallothionein I/II in laryngeal squamous cell cancer.

MCM2, MCM3 and MCM7 are minichromosome maintenance proteins found in dividing cells and they play a role in DNA synthesis. Increased MCM expression level is observed in cells of different cancer types. Additionally, metallothioneins (MT-I/II) are involved in control of cell proliferation and differentiation and changes of their expression are observed in many types of cancer. Ki-67 is known cancer cell proliferation antigen currently used in prognostic evaluation. The study material consisted of 83 laryngeal squamous cell cancer (LSCC) cases and 10 benign hypertrophic lesions of larynx epithelium as a control group. For the present study, laryngeal cancer cell line HEp-2 and human keratinocytes were employed, and to evaluate expression of all the markers, immunohistochemical method (IHC), immunofluorescence (IF) and western blot analysis were used. Statistical analysis showed strong positive correlation between expression of MCM2, MCM3, MCM7 and Ki-67 antigen in LSCC. Additionally, moderate positive correlation was observed between MCM3 and MT-I/II expression. In cancer cells, the level of expression of MCM3, MCM2, MCM7 and Ki-67 markers was increasing with the grade of LSCC malignancy. IF and western blot analysis showed higher MCM2, MCM3, MCM7 expression in HEp-2 cells in comparison to their expression in keratinocytes. MCM proteins might be useful markers of cell proliferation in LSCC.

Xenopus LAP2ß protein knockdown affects location of lamin B and nucleoporins and has effect on assembly of cell nucleus and cell viability.

Xenopus LAP2ß protein is the single isoform expressed in XTC cells. The protein localizes on heterochromatin clusters both at the nuclear envelope and inside a cell nucleus. The majority of XLAP2ß fraction neither colocalizes with TPX2 protein during interphase nor can be immunoprecipitated with XLAP2ß antibody. Knockdown of the XLAP2ß protein expression in XTC cells by synthetic siRNA and plasmid encoded siRNA resulted in nuclear abnormalities including changes in shape of nuclei, abnormal chromatin structure, loss of nuclear envelope, mislocalization of integral membrane proteins of INM such as lamin B2, mislocalization of nucleoporins, and cell death. Based on timing of cell death, we suggest mechanism associated with nucleus reassembly or with entry into mitosis. This confirms that Xenopus LAP2 protein is essential for the maintenance of cell nucleus integrity and the process of its reassembly after mitosis.

Expression of metallothioneins I and II in kidney of doxorubicin-treated rats.

Metallothioneins I/II (MT) are commonly expressed in mammalian tissues and are highly inducible in the response to stress conditions. Doxorubicin (DOX) intoxication promotes oxidative stress and subsequent apoptosis leading to kidney damage. The present study investigates a correlation between endogenous MT expression and DOX-induced apoptosis in renal tubular cells. Experiments were conducted on Buffalo rats receiving DOX (8 mg/kg b.w. for 3 weeks) versus control rats injected with saline. The histopathological alterations and apoptosis (TUNEL) were evaluated in tissue sections. MT expression and tissue localization was examined using immunohistochemical method (IHC). Western blot (WB) was used to evaluate pro-caspase-3, active caspase-3 and MT expression level in tissue homogenates. Examination of renal tissue revealed severe nephrotoxicity in DOX-treated animals. Apoptosis was observed in distal convoluted tubular cells, whereas MT was detected in proximal tubular cells. A significant increase in pro-caspase-3, active caspase-3 and MT expression levels (WB) were seen in DOX group. Positive correlations between histopathological lesions, apoptosis and MT expression were observed. The results obtained in this study could suggest the protective and antiapoptotic effect of MT expression in renal proximal tubular cells under DOX intoxication.

Arterial wall lymphangiogenesis is increased in the human iliac atherosclerotic arteries: involvement of CCR7 receptor.

Twenty-six iliac artery segments were divided in two groups: atherosclerotic (A) and nonatherosclerotic (NA). Expression of LYVE-1, VEGF-C, VEGF-D, and CCR7 receptor were studied with immunohistochemistry (IHC) and Western blot (WB). IHC was performed on 26 samples of iliac arteries obtained from deceased 19 organ donors. The samples were divided into an atherosclerotic group (A) [subjects with history of cardiovascular disease (hypertension, ischemic heart disease) or/and diabetes] (n=16), and a nonatherosclerotic group (NA) [subjects without any known cardiovascular diseases or cardiovascular risk factors] (n=10). WB was performed on 19 iliac artery segments obtained from two groups, based on clinical data: an atherosclerotic group (A) [patients with atherosclerosis, who underwent surgery for lower limb ischemia] (n=10), and a nonatherosclerotic group (NA) [deceased organ donors without cardiovascular diseases/risk factors (n=9)]. Expression of LYVE-1, VEGF-C, VEGF-D, and CCR-7 was increased in atherosclerotic arteries. Positive correlations between LYVE-1 and VEGF-C expression in the intima-media complex assessed by IHC: (r=0.54; p=0.005) and WB: (r=0.47; p=0.005) were found. Positive correlations between expression of CCR-7 and other markers were observed. Lymphangiogenesis is enhanced within the atherosclerotic arterial wall. Our results confirm lymphatic system activation with increased lymphangiogenesis and lymphocyte/macrophage trafficking in atherosclerosis.

Nogo-B expression, in arterial intima, is impeded in the early stages of atherosclerosis in humans.

Nogo-B (Reticulon 4B) is considered to be a novel vascular marker, which may have a protective role in injury-induced neointima formation and atherosclerosis. Nogo A/B is found to be crucial for monocyte/macrophage recruitment in acute inflammation and it is expressed in CD68 + macrophages. We hypothesize that macrophage infiltration in atherosclerosis is not dependent on Nogo-B expression in arterial wall. We have assessed Nogo-B expression and macrophage accumulation in the iliac arteries of healthy organ donors and organ donors with cardiovascular risk factors. Paraffin sections of 66 iliac arteries, from 44 deceased organ donors (17 women and 27 men), were studied. The healthy and cardiovascular risk (CVR) subgroups were created. With regard to staging of the atherosclerotic process, the thickness of arterial intima was measured in digitalized images of H+E stained tissue sections. Immunohistochemical reactions (Nogo-B and CD68) were carried out in all arteries (66 samples). Western blotting (WB-19 samples) and real-time PCR (27 samples) were performed on selected arteries. Significantly higher Nogo-B expression was demonstrated in the intima of the healthy subjects' subgroup, using immunohistochemistry. WB and real-time PCR revealed a trend toward lower Nogo-B expression in the adventitia of the CVR subgroup. Furthermore, the thickness of the intima was found to negatively correlate with the expression of Nogo-B in the intima and media (r = -0.32; p < 0.05; r = -0.32; p < 0.05). Macrophage infiltrates were more prominent in intima of CVR subjects (0.65 vs 3.52 a.u.; p < 0.01). Macrophage density in intima increased with atherosclerosis progression (r = 0.37; p < 0.01). CD68 macrophages density in adventitia was lower in CVR arteries than in healthy arteries. The expression of Nogo-B, in arterial intima, is impeded in the early stages of atherosclerosis. Accumulation of arterial intimal CD68 macrophages has been shown to progress; however, the overall macrophage density in the adventitia is reduced in arteries shown to have intimal thickening. Macrophage infiltration is not accompanied by Nogo-B expression in atherosclerotic arteries.

Characteristics of MIC-1 antlerogenic stem cells and their effect on hair growth in rabbits.

AIM: We characterized growth factors produced by MIC-1 antlerogenic stem cells and attempted to apply those cells to stimulate hair growth in rabbits. MATERIALS AND METHODS: We evaluated the gene and protein expression of growth factors by immunocytochemical and molecular biology techniques in MIC-1 cells. An animal model was used to assess the effects of xenogenous stem cells on hair growth. In the experimental group, rabbits were intradermally injected with MIC-1 stem cells, whereas the control group rabbits were given vehicle-only. After 1, 2 and 4 weeks, skin specimen were collected for histological and immunohistochemical tests. RESULTS: MIC-1 antlerogenic stem cells express growth factors, as confirmed at the mRNA and protein levels. Histological and immunohistochemical analysis demonstrated an increase in the number of hair follicles, as well as the amount of secondary hair in the follicles, without an immune response in animals injected intradermally with MIC-1 cells, compared to animals receiving vehicle-alone. CONCLUSION: MIC-1 cells accelerated hair growth in rabbits due to the activation of cells responsible for the regulation of the hair growth cycle through growth factors. Additionally, the xenogenous cell implant did not induce immune response.

In vitro effect of quercetin on human gastric carcinoma: targeting cancer cells death and MDR.

The benefits of plant polyphenols as chemotherapeutic agents are of great interest due to their possible anti-cancerogenic activities. Results available up to now suggest that flavonoid quercetin induces lethal effect in many types of tumours and may sensitize resistant cells to drugs. The aim of our study was to examine the effect of quercetin on human gastric carcinoma cells and to determine mode of its action. Parental EPG85-257P cell line and its daunorubicin-resistant variant EPG85-257RDB were used as cell models. Our data revealed that quercetin exerted antiproliferative impact on studied cells (with IC(50) value of 12 µM after 72 h), mainly through induction of apoptosis. In sensitive cells cytostatic drug and flavonoid had synergistic effects, in EPG85-257RDB cells quercetin acted as a chemosensitizer. Its impact on resistance mechanism involved decrease of P-glycoprotein expression, inhibition of drug transport and downregulation of ABCB1 gene expression. The results demonstrate that quercetin may be considered as a prospective drug to overcome classical resistance in gastric cancer cells.

Embryonic and adult isoforms of XLAP2 form microdomains associated with chromatin and the nuclear envelope.

Laminin-associated polypeptide 2 (LAP2) proteins are alternatively spliced products of a single gene; they belong to the LEM domain family and, in mammals, locate to the nuclear envelope (NE) and nuclear lamina. Isoforms lacking the transmembrane domain also locate to the nucleoplasm. We used new specific antibodies against the N-terminal domain of Xenopus LAP2 to perform immunoprecipitation, identification and localization studies during Xenopus development. By immunoprecipitation and mass spectrometry (LC/MS/MS), we identified the embryonic isoform XLAP2γ, which was downregulated during development similarly to XLAP2ω. Embryonic isoforms XLAP2ω and XLAP2γ were located in close association with chromatin up to the blastula stage. Later in development, both embryonic isoforms and the adult isoform XLAP2ß were localized in a similar way at the NE. All isoforms colocalized with lamin B2/B3 during development, whereas XLAP2ß was colocalized with lamin B2 and apparently with the F/G repeat nucleoporins throughout the cell cycle in adult tissues and culture cells. XLAP2ß was localized in clusters on chromatin, both at the NE and inside the nucleus. Embryonic isoforms were also localized in clusters at the NE of oocytes. Our results suggest that XLAP2 isoforms participate in the maintenance and anchoring of chromatin domains to the NE and in the formation of lamin B microdomains.

Quercetin as a potential modulator of P-glycoprotein expression and function in cells of human pancreatic carcinoma line resistant to daunorubicin.

P-glycoprotein (P-gp) is one of the ABC transporters responsible for the resistance of several tumours to successful chemotherapy. Numerous agents are capable of interfering with the P-gp-mediated export of drugs but unfortunately most of them produce serious side effects. Some plant polyphenols, including the flavonol quercetin (Q), manifest anti-neoplastic activity mainly due to their influence on cell cycle control and apoptosis. Reports are also available which show that Q may intensify action of cytostatic drugs and suppress the multidrug resistance (MDR) phenomenon. The study aimed at determination if Q sensitizes cells resistant to daunorubicin (DB) through its effect on P-gp expression and action. The experiments were conducted on two cell lines of human pancreatic carcinoma, resistant to DB EPP85-181RDB and sensitive EPP85-181P as a comparison. Cells of both lines were exposed to selected concentrations of Q and DB, and then membranous expression of P-gp and its transport function were examined. The influence on expression of gene for P-gp (ABCB1) was also investigated. Results of the studies confirmed that Q affects expression and function of P-gp in a concentration-dependent manner. Moreover it decreased expression of ABCB1. Thus, Q may be considered as a potential modulator of P-gp.