683 research outputs found
Biosynthesis and Characterization of Silver Nanoparticles from the Extremophile Plant Aeonium haworthii and Their Antioxidant, Antimicrobial and Anti-Diabetic Capacities
No full textThe present paper described the first green synthesis of silver nanoparticles (AgNPs) from the extremophile plant Aeonium haworthii. The characterization of the biosynthesized silver nanoparticles was carried out by using UV-Vis, FTIR and STM analysis. The antioxidant, antidiabetic and antimicrobial properties were also reported. The newly described AgNPs were spherical in shape and had a size of 35-55 nm. The lowest IC50 values measured by the DPPH assay indicate the superior antioxidant behavior of our AgNPs as opposed to ascorbic acid. The silver nanoparticles show high antidiabetic activity determined by the inhibitory effect of alpha amylase as compared to the standard Acarbose. Moreover, the AgNPs inhibit bacterial growth owing to a bactericidal effect with the MIC values varying from 0.017 to 1.7 mu g/mL. The antifungal action was evaluated against Candida albicans, Candida tropicalis, Candida glabrata, Candida sake and non-dermatophytic onychomycosis fungi. A strong inhibitory effect on Candida factors' virulence was observed as proteinase and phospholipase limitations. In addition, the microscopic observations show that the silver nanoparticles cause the eradication of blastospores and block filamentous morphogenesis. The combination of the antioxidant, antimicrobial and antidiabetic behaviors of the new biosynthesized silver nanoparticles highlights their promising use as natural phytomedicine agents
Linear polarization measurement of interband transitions in superdeformed (190)Hg: model-independent evidence for octupole vibrational structures
No full textThe linear polarization of γ rays between excited and yrast superdeformed (SD) states in 190Hg was measured using the four-element CLOVER detectors of the EUROBALL IV γ-ray spectrometer. This measurement shows in a model-independent way that the interband transitions which compete with the highly collective in-band quadrupole transitions are largely enhanced electric dipoles. Not only do these results represent the first measurement of the multipolarity of transitions between different SD states, but they also provide strong evidence for the interpretation of the structures in the SD minimum of the A∼190 region in terms of octupole excitations.A. Korichi, A. N. Wilson, F. Hannachi, A. Lopez-Martens, M. Rejmund, C. Schück, Ch. Vieu, G. Chmel, A. Görgen, H. Hübel, D. Rossbach, S. Schönwasser, M. Bergström, B. M. Nyakó, J. Timár, D. Bazzacco, S. Lunardi, C. Rossi-Alvarez, P. Bednarczyk, N. Kintz, S. Naguleswaran, A. Astier, D. M. Cullen, J. F. Sharpey-Schafer, T. Lauritsen, and R. Wadswort
Boosting sustainable water production by upstream integration of desalination with saltworks in the Mediterranean region
No full textSEArcularMINE is an EU project that is focused on mineral extraction from saltwork bitterns, adopting a circular approach. Within this context, this work shows the possibility of completing the circular scheme with an upwind integration of seawater desalination that can provide freshwater to the local community but also use the brine reject to feed the saltwork in order to increase its productivity. In this study, a specific case of a natural saltwork in Trapani (Italy) is presented, assuming to place a desalination plant very close to the saltworks, so that the brine can be sent there without an additional energy input. After choosing the best desalination technology, demonstrating that Reverse Osmosis (RO) is more suitable than thermal processes from both economic and environmental point of view, the details of the RO design are presented. Then, preliminary calculations using a simple model for the saltwork ponds have been performed, showing that the brine feed can either increase the salt productivity by more than 50% or that the ponds surface can be reduced by more than 40%. Finally, evaporation experiments on desalination brines have been performed to demonstrate that no changes in salt quality occur compared to the standard seawater fee
Effects of cultivation on chemical and biochemical properties of dryland soils from southern Tunisia
No full textThe progressive degradation of cultivated drylands has been mainly ascribed to adoption of intensive soil use, namely repeated soil cultivation with external inputs and disturbances. Consequently, soil managements in equilibrium with environmental and social constrains are required to conserve and improve the soil fertility. We evaluated the impact of soil cultivation and management on chemical and biochemical properties of dryland soils from the Tunisian Jeffara Plain. This study considered three sites (Chenini Nahel, Matmata Nouvelle, and Menzel Habib), with both non-cultivated and cultivated soils. These latter were subjected to different soil management: organic fertilization and irrigation by submersion, chemical fertilization and drip irrigation, no fertilization and sporadic watering. The results showed that the addition of organic matter as compost or manure combined with irrigation may favor pH reduction, with consequently higher enzymatic activity and organic matter storage. The latter occurred because of the encapsulation of organic particles into collars made of re-precipitated gypsum and calcite. In cases where chemical fertilization and drip irrigation were applied, the organic matter stabilization occurred only at the surface; at depth we observed a reduction of organics due to microbially-mediated mineralization processes. When neither organic amendment nor water was supplied, no substantial difference occurred between cultivated and non-cultivated soils. We concluded that, in drylands,
agricultural managements providing the use of water and organic amendments is the way to increase soil organic matter storage and improve physical, chemical and biological properties so to enhance the soil fertility
Production and Characterization of New Biosurfactants/Bioemulsifiers from Pantoea alhagi and Their Antioxidant, Antimicrobial and Anti-Biofilm Potentiality Evaluations
No full textThe present work aimed to develop rapid approach monitoring using a simple selective method based on a positive hemolysis test, oil spreading activity and emulsification index determinations. It is the first to describe production of biosurfactants (BS) by the endophytic Pantoea alhagi species. Results indicated that the new BS evidenced an E24 emulsification index of 82%. Fourier-transform infrared (FTIR) results mentioned that the described BS belong to the glycolipid family. Fatty acid profiles showed the predominance of methyl 2-hyroxydodecanoate in the cell membrane (67.00%) and methyl 14-methylhexadecanoate (12.05%). The major fatty acid in the BS was oleic acid (76.26%), followed by methyl 12-methyltetradecanoate (10.93%). Markedly, the BS produced by the Pantoea alhagi species exhibited antimicrobial and anti-biofilm activities against tested human pathogens. With superior antibacterial activity against Escherchia coli and Staphylococcus aureus, a high antifungal effect was given against Fusarium sp. with a diameter of zone of inhibition of 29.5 mm, 36 mm and 31 mm, obtained by BS dissolved in methanol extract. The DPPH assay indicated that the BS (2 mg/mL) showed a higher antioxidant activity (78.07 inhibition percentage). The new BS exhibited specific characteristics, encouraging their use in various industrial applications
Identification of conserved genes linked to responses to abiotic stresses in leaves among different plant species
No full textAs a consequence of global climate change, certain stress factors that have a negative impact on crop productivity such as heat, cold, drought and salinity are becoming increasingly prevalent. We conducted a meta-analysis to identify genes conserved across plant species involved in (1) general abiotic stress conditions, and (2) specific and unique abiotic stress factors (drought, salinity, extreme temperature) in leaf tissues. We collected raw data and re-analysed eight RNA-Seq studies using our previously published bioinformatic pipeline. A total of 68 samples were analysed. Gene set enrichment analysis was performed using MapMan and PageMan whereas DAVID (Database for Annotation, Visualisation and Integrated Discovery) was used for metabolic process enrichment analysis. We identified of a total of 5122 differentially expressed genes when considering all abiotic stresses (3895 were upregulated and 1227 were downregulated). Jasmonate-related genes were more commonly upregulated by drought, whereas gibberellin downregulation was a key signal for drought and heat. In contrast, cold stress clearly upregulated genes involved in ABA (abscisic acid), cytokinin and gibberellins. A gene (non-phototrophic hypocotyl) involved in IAA (indoleacetic acid) response was induced by heat. Regarding secondary metabolism, as expected, MVA pathway (mevalonate pathway), terpenoids and alkaloids were generally upregulated by all different stresses. However, flavonoids, lignin and lignans were more repressed by heat (cinnamoyl coA reductase 1 and isopentenyl pyrophosphatase). Cold stress drastically modulated genes involved in terpenoid and alkaloids. Relating to transcription factors, AP2-EREBP, MADS-box, WRKY22, MYB, homoebox genes members were significantly modulated by drought stress whereas cold stress enhanced AP2-EREBPs, bZIP members, MYB7, BELL 1 and one bHLH member. C2C2-CO-LIKE, MADS-box and a homeobox (HOMEOBOX3) were mostly repressed in response to heat. Gene set enrichment analysis showed that ubiquitin-mediated protein degradation was enhanced by heat, which unexpectedly repressed glutaredoxin genes. Cold stress mostly upregulated MAP kinases (mitogen-activated protein kinase). Findings of this work will allow the identification of new molecular markers conserved across crops linked to major genes involved in quantitative agronomic traits affected by different abiotic stress
Collective excitations in the superdeformed well
No full textCollective excitations are commonplace features in nuclei at normal deformation. It has been suggested that both in the A\sim 190 and 150 superdeformed (SD) nuclei, collective vibrational states might occur in the same excitation energy range as quasi-particle and single-particle excitations. In particular, the large deformation associated with SD nuclei brings together orbitals from many spherical shells and leads to the close proximity of states with opposite parity, favouring octupole shape vibrations. However, to date, \sim 200 SD bands have been reported in more than 50 nuclei and in most cases, the excited SD bands have been interpreted as single or quasi-particle excitations. Only in very few cases, has the collective excitation scenario been suggested. Where are the collective states in SD nuclei? The question is particularly relevant in even--even A=190 nuclei in which SD states are observed at lower rotational frequency and hence the additional influence of the pair gap makes the collective excitations more competitive with quasi-particle excitations.F. Hannachi, A. Korichi, A.N. Wilson, A. Lopez-Martens, M. Rejmund, C. Schueck, Ch. Vieu, G. Chmel, A. Goergen, H. Huebel, D. Rossbach, S. Schoenwasser, M. Bergstroem, B.M. Nyako, J. Timar, D. Bazzacco, S. Lunardi, C. Rossi-Alvarez, P. Bednarczyk, N. Kintz, S. Naguleswaran, A. Astier, D.M. Cullen, J.F. Sharpey-Schafer, T. Lauritsen, R. Wadsworthhttp://th-www.if.uj.edu.pl/acta/vol32/abs/v32p1083.ht
Human leukocyte antigen (HLA-F) polymorphism is associated with chronic HBV infection
No full textHuman leukocyte antigen (HLA)-F has been involved in immune regulation of infectious diseases. However, the role of HLA-F polymorphisms in hepatitis B infection outcomes remains unclear. Here, we aimed to determine HLA-F polymorphism implication in chronic HBV. Genotype analysis was performed for three single nucleotide polymorphisms (SNPs) of HLA-F and one SNP of HLA-E using PCR-SSP, in 252 Tunisian patients with chronic HBV infection stratified according to their HBV DNA levels (140 patients with low HBV DNA levels < 2000 IU/mL and 112 patients with high HBV DNA levels >= 2000 IU/mL) and 240 healthy controls (CTRL). The three HLA-F SNPs (HLA-F* 01:02, -F* 01:03 and -F* 01:04) have the same allelic and genotypic frequencies in patients and in CTRL. We reported a low HLA-F* 01:02 and -F*01:04 allelic frequencies in the Tunisian population; however, high HLA-F* 01:03 allele frequencies were observed (17%). A significant association was found between the HLA-F* 01:03 allele and decreased level of HBV DNA (P = 0.02 OR 0.56, 95% CI 0.35-0.92). No significant differences were observed in haplotype distribution between patients and CTRL. A significant association of HLA-F* 01:03 with the level of HBV DNA suggests an important role of HLA-F in HBV replication control
Diuron environmental levels effects on marine nematodes: Assessment of ecological indices, taxonomic diversity, and functional traits
No full textCoastal marine systems are the most sensitive zones to emerging pollutants. The present study aims to investigate the effect of Diuron on the meiofaunal assemblages, collected from the Bizerte channel (Tunisia). Microcosm experiments were set up using four increasing Diuron concentrations [D1 (10 ng g−1 dry weight (DW)), D2 (50 ng g−1 DW), D3 (250 ng g−1 DW) and (1250 ng g−1 DW)] compared to non-contaminated sediments (controls) and all plots were incubated for 30 days. Our results show that Diuron-supplemented sediments provoked the significant decrease of meiofaunal abundance as well as a change in nematodes' diversity and structure composition. All univariate indices, as well as the cumulative k-dominance, were lower in the Diuron than the control plot. Additionally, the ordination of treatments according to the two-dimensional nMDS plots analysis showed a clear structural separation of the Diuron treated replicates from the controls based on the functional groups lists. These current data emphasize the utility of the use of biological traits in the detection of disturbances in the aquatic biotope
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