Microfacies and cycle stacking pattern in Liassic peritidal carbonate platform strata, Gavrovo-Tripolitza platform, Peloponnesus, Greece

Platform carbonate sediments of Liassic age cropping out in the area of the Pigadi-Fokianos Gulf (SE of Leonidion, Peloponnesus) have been investigated in order to determine their depositional environment. Facies analysis allowed the recognition of several microfacies types and their cyclic stacking pattern. The carbonates were deposited in a restricted inner platform environment (lagoon-peritidal domain) and are arranged into small-scale shallowing-upward cycles. Palaeosol horizons containing typical pedogenic features are developed on the top of the peritidal facies or are directly superimposed on subtidal deposits, forming diagenetic caps. This implies repeated sea-level fluctuations and periodic emersion episodes. The presence of orbitally forced cyclicity though is mostly probable, cannot be clearly documented by the available data. The studied carbonates are comparable with other coeval analogous peritidal cycles of the same age along the southern margin of the Tethys.     

Neuroprotective Effects of IGF-I Following Kainic Acid-Induced Hippocampal Degeneration in the Rat

Insulin-like growth factor I (IGF-I) has been shown to act as a neuroprotectant both in in vitro studies and in in vivo animal models of ischemia, hypoxia, trauma in the brain or the spinal cord, multiple and amyotrophic lateral sclerosis, Alzheimer’s and Parkinson’s disease. In the present study, we investigated the neuroprotective potential of IGF-I in the “kainic acid-induced degeneration of the hippocampus” model of temporal lobe epilepsy. Increased cell death—as detected by FluoroJade B staining—and extensive cell loss—as determined by cresyl violet staining—were observed mainly in the CA3 and CA4 areas of the ipsilateral and contralateral hippocampus, 7 days following intrahippocampal administration of kainic acid. Kainic acid injection also resulted in intense astrogliosis—as assessed by the number of glial fibrillary acidic protein (GFAP) immunopositive cells—in both hemispheres, forming a clear astroglial scar ipsilaterally to the injection site. Heat-shock protein 70 (Hsp70) immunopositive cells were also observed in the ipsilateral dentate gyrus (DG) following kainic acid injection. When IGF-I was administered together with kainic acid, practically no signs of degeneration were detected in the contralateral hemisphere, while in the ipsilateral, there was a smaller degree of cell loss, reduced number of FluoroJade B-stained cells, decreased reactive gliosis and fewer Hsp70-positive cells. Our present results extend further the cases in which IGF-I is shown to exhibit neuroprotective properties in neurodegenerative processes in the CNS.     

Immunolocalization of carbonic anhydrase and phosphoenolpyruvate carboxylase in developing seeds of Medicago sativa.

To investigate the role of carbonic anhydrase (CA; EC 4.2.1.1) and phosphoenolpyruvate carboxylase (PEPC; EC 4.1.1.31) during Medicago sativa seed development, the distribution of both proteins was examined using an immunohistological approach. Both enzymes are co-localized in most ovular and embryonic tissues. In early stages of seed development, both proteins were abundant in embryo and integuments, while at subsequent stages both proteins are accumulated in endosperm, nucellus and integuments. At late stages of seed development when both endosperm and nucellus are degraded, significant accumulation of both proteins was observed in the embryo proper. Chlorophyll was found to accumulate in embryos after the heart stage and reached a maximum at mature stage. It is suggested that CA and PEPC play a role in respiratory carbon dioxide refixation while generating malate to support amino acid and/or fatty acids biosynthesis.     

Ribosomes containing mutants of L4 ribosomal protein from Thermus thermophilus display multiple defects in ribosomal functions and sensitivity against erythromycin

Protein L4 from Thermus thermophilus (TthL4) was heterologously overproduced in Escherichia coli cells. To study the implication of the extended loop of TthL4 in the exit-tunnel and peptidyltransferase functions, the highly conserved E56 was replaced by D or Q, while the semiconserved G55 was changed to E or S. Moreover, the sequence -G55E56- was inverted to -E55G56-. When we incorporated these mutants into E. coli ribosomes and investigated their impact on poly(Phe) synthesis, high variations in the synthetic activity and response to erythromycin of the resulting ribosomes were observed. In the absence of erythromycin, ribosomes harboring mutations G55E and E56D in TthL4 protein were characterized by low activity in synthesizing poly(Phe) and decreased capability in binding tRNA at the A site. On the other hand, ribosomes possessing mutations G55E, G55S, G55E-E56G, or E56Q in TthL4 protein were unexpectedly more sensitive to erythromycin. Evidence in support of these findings was drawn by in vivo experiments, assessing the erythromycin sensitivity of E. coli cells expressing wild-type or mutant TthL4 proteins. Our results emphasize the role of the extended loop of L4 ribosomal protein in the exit-tunnel and peptidyltransferase center functions.     

Structural destabilization of the recombinant thermophilic TthL11 ribosomal protein by a single amino acid substitution

Thermus thermophilus L11 protein has previously been reported to be resistant against tryptic and chymotryptic proteolysis under native conditions. With a single amino acid substitution, namely Trp101Arg, conformational changes were induced that resulted in the exhibition of specific amino acids that served as targets for tryptic and chymotryptic action and rendered the protein highly unstable even during purification. This unexpected process was evidenced by the isolation with size exclusion gel chromatography of the well-structured chymotryptic N-terminal domain in a high amount and its characterization both by Edman degradation and QTOF-EMS spectroscopy. On the other hand, the substitution of Val38Cys, which did not contribute to structural changes, indicates a very possible implication of this amino acid in the protein methylation process. The data reported in this work illustrate the distinctive amino acid dynamics in a thermophilic protein, which, while serving the function common to its counterparts from mesophilic organisms, has had to adapt to the extreme environmental conditions typical of thermophilic organisms.     

Microrna expression signatures predict patient progression and disease outcome in pediatric embryonal central nervous system neoplasms

Background

Although, substantial experimental evidence related to diagnosis and treatment of pediatric central nervous system (CNS) neoplasms have been demonstrated, the understanding of the etiology and pathogenesis of the disease remains scarce. Recent microRNA (miRNA)-based research reveals the involvement of miRNAs in various aspects of CNS development and proposes that they might compose key molecules underlying oncogenesis. The current study evaluated miRNA differential expression detected between pediatric embryonal brain tumors and normal controls to characterize candidate biomarkers related to diagnosis, prognosis and therapy.

Methods

Overall, 19 embryonal brain tumors; 15 Medulloblastomas (MBs) and 4 Atypical Teratoid/Rabdoid Tumors (AT/RTs) were studied. As controls, 13 samples were used; The First-Choice Human Brain Reference RNA and 12 samples from deceased children who underwent autopsy and were not present with any brain malignancy. RNA extraction was carried out using the Trizol method, whilst miRNA extraction was performed with the mirVANA miRNA isolation kit. The experimental approach included miRNA microarrays covering 1211 miRNAs. Quantitative Real-Time Polymerase Chain Reaction was performed to validate the expression profiles of miR-34a and miR-601 in all 32 samples initially screened with miRNA microarrays and in an additional independent cohort of 30 patients (21MBs and 9 AT/RTs). Moreover, meta-analyses was performed in total 27 embryonal tumor samples; 19 MBs, 8 ATRTs and 121 control samples. Twelve germinomas were also used as an independent validation cohort. All deregulated miRNAs were correlated to patients’ clinical characteristics and pathological measures.

Results

In several cases, there was a positive correlation between individual miRNA expression levels and laboratory or clinical characteristics. Based on that, miR-601 could serve as a putative tumor suppressor gene, whilst miR-34a as an oncogene. In general, miR-34a demonstrated oncogenic roles in all pediatric embryonal CNS neoplasms studied.

Conclusions

Deeper understanding of the aberrant miRNA expression in pediatric embryonal brain tumors might aid in the development of tumor-specific miRNA signatures, which could potentially afford promising biomarkers related to diagnosis, prognosis and patient targeted therapy.

     

The experience of brace treatment in children/adolescents with scoliosis

Background

In a previous study, a number of genes, associated with spine musculoskeletal deformity phenotypes in mouse and in synteny between mouse and man, were identified as candidate genes for IS. Among these genes, MATN 1, which carries a polymorphic microsatellite marker within its sequence, was selected for a linkage analysis. MATN1 is localised at 1p35 and is mainly expressed in cartilage. The objective of this study was to assess a linkage disequilibrium between the matrilin-1 (MATN 1) gene and the idiopathic scoliosis (IS).

Methods

The genetic study was conducted on a population of 81 trios, each consistent of a daughter/son affected by idiopathic scoliosis (IS) and both parents. In all trios components, the region of MATN1 gene containing the microsatellite marker was amplified by a polymerase chain reaction. The amplicons were analysed by a DNA sequencer-genotyper. The statistical linkage analysis was performed using the extended transmission/disequilibrium test.

Results

Three microsatellite polymorphisms, respectively consisting of 103 bp, 101 bp and 99 bp, were identified. ETDT evidenced a significant preferential transmission for the 103 bp allele (Chi-square = 5.058, df = 1, P = 0.024)

Conclusion

The results suggest that the familial idiopathic scoliosis is associated to the MATN1 gene.     

Saffron (<Emphasis Type="Italic">Crocus sativus</Emphasis> L.) Tea Intake Prevents Learning/Memory Defects and Neurobiochemical Alterations Induced by Aflatoxin B<Subscript>1</Subscript> Exposure in Adult Mice

This study aimed to investigate the potential neurotoxic effects of aflatoxin B₁ (AFB₁) and the preventive effects of saffron. Male Balb-c mice received AFB₁ (0.6 mg/kg/day intraperitoneally for 4 days), saffron infusion (90 mg styles/200 mL, ad libitum access for 2 weeks) or saffron infusion plus AFB₁ (saffron treatment as previously plus 0.6 mg AFB₁/kg/day intraperitoneally for the last 4 days). Control mice were intraperitoneally injected with DMSO:saline (1:1, v/v) during AFB₁ treatment. Learning/memory was assessed by passive avoidance task. The activity of acetylcholinesterase [AChE, salt-(SS)/detergent-soluble(DS) isoforms], butyrylcholinesterase (BuChE, SS/DS isoforms), monoamine oxidase (MAO-A, MAO-B), the levels of lipid peroxidation (malondialdehyde, MDA) and reduced glutathione (GSH), were determined in whole brain (minus cerebellum) and cerebellum. We demonstrate for the first time that AFB₁ administration impaired the memory of adult mice and decreased significantly whole brain AChE and BuChE activity, cerebellar AChE activity and cerebral GSH content. Moreover, MAO isoforms activity in whole brain, MAO-B activity in cerebellum and MDA levels of both tissues were significantly higher after AFB₁ treatment. Pre-treatment with saffron prevented memory decline, activation of MAO-A and MAO-B in whole brain and cerebellum, respectively, and lipid peroxidation triggered by AFB₁. Interestingly, the activity of AChE isoforms in whole brain, DS-AChE in cerebellum and GSH levels of both tissues were further significantly decreased in saffron?+AFB₁-treated mice compared with AFB₁ group. Our findings support the neuroprotective efficacy of saffron against AFB₁ in adult mice.