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1.
J. Cosmidis K. Benzerara E. Gheerbrant I. Estève B. Bouya M. Amaghzaz 《Geobiology》2013,11(2):139-153
Micrometer‐sized spherical and rod‐shaped forms have been reported in many phosphorites and often interpreted as microbes fossilized by apatite, based on their morphologic resemblance with modern bacteria inferred by scanning electron microscopy (SEM) observations. This interpretation supports models involving bacteria in the formation of phosphorites. Here, we studied a phosphatic coprolite of Paleocene age originating from the Ouled Abdoun phosphate basin (Morocco) down to the nanometer‐scale using focused ion beam milling, transmission electron microscopy (TEM), and scanning transmission x‐ray microscopy (STXM) coupled with x‐ray absorption near‐edge structure spectroscopy (XANES). The coprolite, exclusively composed of francolite (a carbonate‐fluroapatite), is formed by the accumulation of spherical objects, delimited by a thin envelope, and whose apparent diameters are between 0.5 and 3 μm. The envelope of the spheres is composed of a continuous crown dense to electrons, which measures 20–40 nm in thickness. It is surrounded by two thinner layers that are more porous and transparent to electrons and enriched in organic carbon. The observed spherical objects are very similar with bacteria encrusting in hydroxyapatite as observed in laboratory experiments. We suggest that they are Gram‐negative bacteria fossilized by francolite, the precipitation of which started within the periplasm of the cells. We discuss the role of bacteria in the fossilization mechanism and propose that they could have played an active role in the formation of francolite. This study shows that ancient phosphorites can contain fossil biological subcellular structures as fine as a bacterial periplasm. Moreover, we demonstrate that while morphological information provided by SEM analyses is valuable, the use of additional nanoscale analyses is a powerful approach to help inferring the biogenicity of biomorphs found in phosphorites. A more systematic use of this approach could considerably improve our knowledge and understanding of the microfossils present in the geological record. 相似文献
2.
Summary In primary cultures, much evidence shows the existence of different subtypes of astrocytes that are not all identified. One
methodology for studying these subtypes can be their cloning. The present investigation shows a method for a direct cloning
of astrocytes without previous immortalization. Astrocytes from the cerebral cortex of newborn rats were cultured, purified
by shaking, and harvested by trypsinization. One single astrocyte was plated in a small volume of a homemade cloning medium.
After getting a colony, successive platings were made using larger and larger vessels, up to 60-mm-diameter petri dishes.
Then, subcultures were made. The yield of the cloning was similar to that of common eukaryotic cell clonings. All along the
cloning procedure, the cells were positively immunostained with anti-glial fibrillary acidic protein antibodies. Cloned cells
from some batches were spindle-shaped, looking like fibroblasts. Nevertheless, they were immunostained with anti-glial fibrillary
acidic protein antibodies, unlike true fibroblasts. These spindle-shaped astrocytes were compared to cells from an astrocytoma
cell line that had the same shape. The growth pattern of the astrocytoma cells was different from that of the astrocytes cloned
from the primary cultures. All the types of studied cells contained glycogen. On the basis of the criteria of morphology,
of glial fibrillary acidic protein immunolabeling, and of glycogen synthesis, the cloned cells kept the characteristics of
astrocytes. This study shows that it is perfectly possible to get clones of astrocytes from one astrocyte without previous
immortalization, giving thus a convenient material for the study of astrocyte biology. 相似文献
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A proximal part of humerus from the basal Ypresian (lowermost Eocene) of the Ouled Abdoun Basin, Morocco, is described as a new genus and species tentatively assigned to the Phaethontidae (tropicbirds). This fossil possibly represents the oldest record of the Phaethontidae and markedly differs from Lithoptila, a contemporaneous Prophaethontidae from the same locality. This new taxon lived in a tropical climate and was probably an efficient flier with pelagic habits, like extant tropicbirds of the genus Phaethon. 相似文献
5.
Jacq L Garnier S Dieudé P Michou L Pierlot C Migliorini P Balsa A Westhovens R Barrera P Alves H Vaz C Fernandes M Pascual-Salcedo D Bombardieri S Dequeker J Radstake TR Van Riel P van de Putte L Lopes-Vaz A Glikmans E Barbet S Lasbleiz S Lemaire I Quillet P Hilliquin P Teixeira VH Petit-Teixeira E Mbarek H Prum B Bardin T Cornélis F;European Consortium on Rheumatoid Arthritis Families 《Arthritis research & therapy》2007,9(4):R63-7
The integrin alpha(v)beta3, whose alpha(v) subunit is encoded by the ITGAV gene, plays a key role in angiogenesis. Hyperangiogenesis is involved in rheumatoid arthritis (RA) and the ITGAV gene is located in 2q31, one of the suggested RA susceptibility loci. Our aim was to test the ITGAV gene for association and linkage to RA in a family-based study from the European Caucasian population. Two single nucleotide polymorphisms were genotyped by PCR-restriction fragment length polymorphism in 100 French Caucasian RA trio families (one RA patient and both parents), 100 other French families and 265 European families available for replication. The genetic analyses for association and linkage were performed using the comparison of allelic frequencies (affected family-based controls), the transmission disequilibrium test, and the genotype relative risk.We observed a significant RA association for the C allele of rs3738919 in the first sample (affected family-based controls, RA index cases 66.5% versus controls 56.7%; P = 0.04). The second sample showed the same trend, and the third sample again showed a significant RA association. When all sets were combined, the association was confirmed (affected family-based controls, RA index cases 64.6% versus controls 58.1%; P = 0.005). The rs3738919-C allele was also linked to RA (transmission disequilibrium test, 56.5% versus 50% of transmission; P = 0.009) and the C-allele-containing genotype was more frequent in RA index cases than in controls (RA index cases 372 versus controls 339; P = 0.002, odds ratio = 1.94, 95% confidence interval = 1.3-2.9). The rs3738919-C allele of the ITGAV gene is associated with RA in the European Caucasian population, suggesting ITGAV as a new minor RA susceptibility gene. 相似文献
6.
Kais Mnafgui Mouna Kchaou Khaled Hamden Fatma Derbali Sadok Slama Mbarek Nasri Hichem Ben Salah Noureddine Allouche Abdelfattah Elfeki 《Journal of physiology and biochemistry》2014,70(1):93-106
Zygophyllum album has been used as herbal medicine in Southern Tunisia to treat several diseases such as diabetes mellitus. This study is aimed to reveal the mechanisms underlying the antihyperglycemic potential, the anti-inflammatory and the protective hematological proprieties of this plant in diabetic rats. The inhibition of the α-amylase activity by different solvent-extract fractions of Z. album was tested in vitro. The fraction endowed with the powerful inhibitory activity against α-amylase was administered to surviving diabetic rats for 30 days. Data from in vitro indicated that each extract from the medicinal plant showed moderate inhibition of α-amylase enzyme except the ethyl acetate extract which was ineffective. The powerful inhibition was achieved by ethanol extract of Z. album (EZA) with an IC50 of 43.48 μg/ml as compared to acarbose (Acar) with an IC50 of 14.88 μg/ml. In vivo, the results showed that EZA decreased the α-amylase levels in serum, pancreas and intestine of diabetic rats by 40 %, 45 % and 46 %, respectively, associated with considerably reduction in blood glucose rate by 61 %. Moreover, the EZA helped to protect the structure and function of the β-cells. Interestingly, EZA had a potent anti-inflammatory effect which is manifested by decreases in CRP and TNF-α levels. Overall, a notable reduction in lipase activity both in serum and small intestine of treated diabetic rats resulted in the improvement of serum and liver lipids profile. Z. album showed a prominent antidiabetic effect via inhibition of carbohydrate and lipid digestive enzymes and ameliorated the inflammation and the disturbance of hematological biomarkers in diabetes. 相似文献
7.
Vinod Kumar Paulisally Hau Yi Lo Hiromi Sawai Naoya Kato Atsushi Takahashi Zhenzhong Deng Yuji Urabe Hamdi Mbarek Katsushi Tokunaga Yasuhito Tanaka Masaya Sugiyama Masashi Mizokami Ryosuke Muroyama Ryosuke Tateishi Masao Omata Kazuhiko Koike Chizu Tanikawa Naoyuki Kamatani Michiaki Kubo Yusuke Nakamura Koichi Matsuda 《PloS one》2012,7(9)
MHC class I polypeptide-related chain A (MICA) molecule is induced in response to viral infection and various types of stress. We recently reported that a single nucleotide polymorphism (SNP) rs2596542 located in the MICA promoter region was significantly associated with the risk for hepatitis C virus (HCV)-induced hepatocellular carcinoma (HCC) and also with serum levels of soluble MICA (sMICA). In this study, we focused on the possible involvement of MICA in liver carcinogenesis related to hepatitis B virus (HBV) infection and examined correlation between the MICA polymorphism and the serum sMICA levels in HBV-induced HCC patients. The genetic association analysis revealed a nominal association with an SNP rs2596542; a G allele was considered to increase the risk of HBV-induced HCC (P = 0.029 with odds ratio of 1.19). We also found a significant elevation of sMICA in HBV-induced HCC cases. Moreover, a G allele of SNP rs2596542 was significantly associated with increased sMICA levels (P = 0.009). Interestingly, HCC patients with the high serum level of sMICA (>5 pg/ml) exhibited poorer prognosis than those with the low serum level of sMICA (≤5 pg/ml) (P = 0.008). Thus, our results highlight the importance of MICA genetic variations and the significance of sMICA as a predictive biomarker for HBV-induced HCC. 相似文献
8.
Abdelhak Khallouk Younes Ahallal Mbarek Doublali Mohamed Fadl Tazi Soufiane Mellas Mohamed Jamal el Fassi Moulay Hassan Farih 《Reviews in urology》2009,11(4):216-218
Renal angiomyolipomas (AMLs) are often associated with tuberous sclerosis. These tumors are predominantly benign, although malignant forms do exist and are known to be associated with renal cell carcinoma. This case report describes a patient with tuberous sclerosis and massive bilateral AML. Total right nephrectomy was performed; histopathologic examination revealed the coexistence of AML and clear cell renal carcinoma in the same kidney. Because differentiation between renal cell carcinoma and AML with minimal or no fat component can be difficult, an accurate diagnosis is critical in the management of renal AML.Key words: Angiomyolipoma, Renal cell carcinoma, Tuberous sclerosisApproximately 80% of patients with tuberous sclerosis complex (TSC) develop renal angiomyolipoma (AML). Although often benign,1,2 malignant AML and renal cell carcinoma (RCC) have also been reported in patients with TSC. The concurrence of renal AML and RCC in the same kidney has also been reported in patients with TSC and has been revealed on pathologic examination.Several criteria can be used to help predict malignancy in renal AML, such as tumor size, tumor size and necrosis, and atypical mitotic figures. We report a case of associated massive bilateral AML and RCC. We discuss the diagnosis and treatment of renal AML and emphasize the possibility of concurrent renal malignancies in patients with TSC. 相似文献
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Nathalie Bardet Nour-Eddine Jalil France de Lapparent de Broin Damien Germain Olivier Lambert Mbarek Amaghzaz 《PloS one》2013,8(7)