Terrestrial pollen record of recent land-use changes around nine North African lakes in the CASSARINA Project

Pollen analyses and related plant macrofossil records are presented from short cores from nine North African lakes in the EU-funded CASSARINA project. Terrestrial pollen reflects human impact on the vegetation and landscape over the last 150–100 years. Pollen changes, aided by radiometric dating, could be correlated with historical developments. The chronology of the landscape changes date other biostratigraphical records reflecting changes in the aquatic ecosystems.Three lakes in Morocco show gradually intensifying land-use over the last century. Accelerated technological development and landscape modification over the last 20 years culminated in one of the lakes being drained and cultivated during the project period. In Tunisia, a nationally unique acid-water lake is threatened by water withdrawal for increased catchment cultivation. The landscape around two other lakes is being increasingly cultivated and urbanised, and water withdrawal to support this has resulted in deleterious effects on the aquatic ecosystems, particularly at the internationally famous Garaet El Ichkeul where reed-marshes and macrophyte beds have been lost. The three lakes in the Egyptian Nile Delta are in the same hydrological system and show parallel changes in the balance between saltmarsh and reed-marsh. Control of Nile floods and year-round irrigation led to marked increases in cultivation in the delta region since ca. 1920. The Aswan High Dam (1964) had little detectable further effect. Documented planting of dates, palms, and olives and of introduced Casuarina and Eucalyptus trees provided a chronology to supplement the unsatisfactory radiometric dating of the sediments in this low-rainfall area.     

OLigonucleotide (Cyanomethyl) Phosphonates

Abstract

A dinucleoside (cyanomethyl) phosphonate has been prepared, and its properties have been studied. This compound was converted into an oligonucleotide possessing alternating (cyanomethyl) phosphonate and phosphodiester backbone groups and its hybridization to complementary DNA and RNA sequences was studied versus methylphosphonate and phosphodiester controls.     

Intérêt de l’étude de l’oxydation de l’ADN des spermatozoïdes par marquage de la 8-oxo-guanine en cytométrie en flux chez l’homme infertile

Oxidative stress in semen is essentially due to excessive production of oxygen-reactive species (ORS) essentially derived from leukocytes. DNA oxidation is due to the direct action of ORS which produce several adducts the most extensively studied of which is 8-oxo-guanine. Integrity of DNA is essential for the fertility of sperm and is an important subject of research for scientists and clinicians all over the world. Although evaluation of the global integrity of sperm DNA has considerably developed over recent years, few tests are available to document oxidative DNA damage. This study was designed to review the various tests of sperm DNA integrity commonly used in the literature and to present the results of our study on DNA oxidation with 8-oxo-guanine labelling by flow cytometry in infertile men. This study was based on 15 semen samples that were submitted to sperm analysis according to WHO guidelines, with determination of the leukocyte concentration by a cytochemical method revealing peroxidase in cytoplasmic granulations. The DNA oxidation study was performed with 8-oxo-guanine labelling by flow cytometry. Linear regression analysis showed a strong correlation between DNA oxidation and leukocyte count in the semen (p = 0.006, r = 0.7). A leukocyte cut-off of 250,000/ml of semen was associated with a significant increase of DNA oxidation (p = 0.03). 8-oxo-guanine can therefore be considered to be a biological marker of the direct action of oxidative stress on sperm DNA which appears to be susceptible to relatively low levels of ORS produced by leukocytes present at concentrations well below the limit of leukospermia defined by WHO.     

New 5-Methylcoumarin derivatives from Ethulia conyzoides

A reinvestigation of the aerial parts of E. conyzoides L. afforded three new 5-methyl coumarins and a degraded nor compound with an eucarvone part. The structures were elucidated using spectral methods and some chemical transformations. The biogenetic relationships of these compounds are discussed.     

Current approaches in identification and isolation of cancer stem cells

Cancer stem cells (CSCs) are tumor cells with initiating ability, self-renewal potential, and intrinsic resistance to conventional therapeutics. Efficient isolation and characterization of CSCs pave the way for more comprehensive knowledge about tumorigenesis, heterogeneity, and chemoresistance. Also a better understanding of CSCs will lead to novel era of both basic and clinical cancer research, reclassification of human tumors, and development of innovative therapeutic strategies. Finding novel diagnostic and effective therapeutic strategies also enhance the success of treatment in cancer patients. There are various methods based on the characteristics of the CSCs to detect and isolate these cells, some of which have recently developed. This review summarized current techniques for effective isolation and characterization of CSCs with a focus on advantages and limitations of each method with clinical applications.     

Optimization of protease production from Bacillus halodurans under solid state fermentation using agrowastes

Marine microbes are potential source for novel metabolites. They are efficient in producing these metabolites utilizing agrowastes. Protease is one of the enzymes which find wide industrial applications. In the present study, protease producing bacteria was isolated from marine sediments and the organism was identified as Bacillus halodurans. The organism was subjected to protease production under solid state fermentation (SSF) using different agrowastes as substrates. Among the substrates used, wheat bran yielded maximum quantity of protease. The fermentation process was carried out under different cultural conditions to optimize the parameters influencing the enzyme production. The results of the stain removal studies by the enzyme revealed the increased efficiency of the microbial enzyme than the commercial detergent.     

In vitro evaluation of human osteoblast-like cell proliferation and attachment on nanostructured fluoridated hydroxyapatite

The effect of the fluorine content and nano-structure of fluoridated hydroxyapatite (FHA) on human osteoblast-like (HO) cell behavior were investigated. FHA nanopowders and bulk nanostructured FHA, produced via mechanical alloying and two-step sintering, respectively, were used. The cytotoxicity of FHA nanopowders was assessed by MTT. Cell attachment to the surface of the bulk nanostructured FHA was evaluated by culturing of HO cells. Although HO cells proliferated 10 % more in contact with FHA nanopowders compared to culture medium without FHA nanopowders, an increase in the fluorine content of FHA caused a delay in the cell proliferation by about 2 days. Cell attachment on the bulk nanostructured FHA did not change the fluorine content.     

Michael adducts of ascorbic acid as inhibitors of protein phosphatase 2A and inducers of apoptosis

Michael adducts of ascorbic acid with alpha,beta-unsaturated carbonyl compounds have been shown to be potent inhibitors of protein phosphatase 1 (PP1) without affecting cell viability at the respective concentrations. Here we were able to show that higher concentrations can partially inhibit PP2A activity and concomitantly induce apoptotic cell death. A nitrostyrene adduct of ascorbic acid proved to be a more potent and effective inhibitor of PP2A as well as a stronger inducer of apoptosis. These adducts only slightly lost their cytotoxic potential in multidrug resistant cells that were 10-fold less sensitive to apoptosis induction by okadaic acid and vinblastine.     

Exceptional ancient DNA preservation and fibre remains of a Sasanian saltmine sheep mummy in Chehrābād,Iran

Mummified remains have long attracted interest as a potential source of ancient DNA. However, mummification is a rare process that requires an anhydrous environment to rapidly dehydrate and preserve tissue before complete decomposition occurs. We present the whole-genome sequences (3.94 X) of an approximately 1600-year-old naturally mummified sheep recovered from Chehrābād, a salt mine in northwestern Iran. Comparative analyses of published ancient sequences revealed the remarkable DNA integrity of this mummy. Hallmarks of postmortem damage, fragmentation and hydrolytic deamination are substantially reduced, likely owing to the high salinity of this taphonomic environment. Metagenomic analyses reflect the profound influence of high-salt content on decomposition; its microbial profile is predominated by halophilic archaea and bacteria, possibly contributing to the remarkable preservation of the sample. Applying population genomic analyses, we find clustering of this sheep with Southwest Asian modern breeds, suggesting ancestry continuity. Genotyping of a locus influencing the woolly phenotype showed the presence of an ancestral ‘hairy’ allele, consistent with hair fibre imaging. This, along with derived alleles associated with the fat-tail phenotype, provides genetic evidence that Sasanian-period Iranians maintained specialized sheep flocks for different uses, with the ‘hairy’, ‘fat-tailed’-genotyped sheep likely kept by the rural community of Chehrābād''s miners.     

Comparison of two chickpea varieties regarding their responses to direct and induced Fe deficiency

The effects of Fe deficiency (whether direct or bicarbonate-induced) on plant morphology, growth parameters, photosynthesis-related pigment contents, gas exchange, and water relations were addressed in two contrasting chickpea varieties (INRAT88 and Chetoui, respectively tolerant and sensitive to Fe deficiency). A marked decrease in the whole plant Fe content was observed in the Fe deprived plants of both varieties, especially the bicarbonate-treated ones, which showed a slower growth development and water deficit stress symptoms (increased leaf tissue osmolality associated with decreased shoot height, increased leaf mass to area ratio, and decreased water content). Both Fe shortage and bicarbonate addition resulted in both varieties in the decline of the photosynthetic pigment contents, contributing to lower photosynthetic efficiency (φ_c) and lower net photosynthesis (A). Fe deficiency reduced the water use efficiency and physiological availability of water too. However, INRAT88 was more tolerant to Fe deficiency than Chetoui, by maintaining a higher growth rate associated with lower respiration rate (R_D), higher chlorophyll a and b concentrations, higher A, lower transpiration rate (E) and a higher water use efficiency (A/E). The present data suggest that the efficient utilisation of Fe for the synthesis of chlorophyll together with the effective control of electron-transport chains at chloroplasts (high A) and mitochondria (low R_D) may account for the higher tolerance of INRAT88 to direct Fe deficiency. Further investigations with respect to oxidative stress and ROS generation, or about photorespiration would be helpful for a better understanding of their interaction with Fe deficiency in this grain legume.