Environmental factors determining regional biodiversity patterns of groundwater fauna in semi-arid aquifers of northwest Algeria

Limnology - This study investigated the biodiversity and hydrochemistry of seven unconfined aquifers located in two hydrogeological complexes in the north-western region of Algeria. The aim of the...     

Improved production of quinone-methide triterpenoids by <Emphasis Type="Italic">Cheiloclinium cognatum</Emphasis> root cultures: possibilities for a non-destructive biotechnological process

Quinone-methide triterpenoids (QMTs) derived from species of the family Celastraceae have long been used as anti-cancer, anti-inflammatory, anti-oxidant, anti-malarial and insecticidal agents. The main problem in producing QMTs on a large-scale from natural sources is the low amounts (<0.4% dry weight) produced by plants grown in vivo. The aim of this study was to compare the levels of QMTs accumulated by roots of Cheiloclinium cognatum cultured in vitro with those of in vivo plants aged 6 months to 10 years. The highest levels of QMTs produced by in vivo specimens were found in root bark of 10-year old plants, but in vitro cultured roots produced 3.52-times more 22β-hydroxy-maytenin and 11.46-times more maytenin. Most importantly, the cultured roots excreted QMTs into the growth medium, thereby facilitating the large-scale production, extraction and purification of these bioactive compounds by means of a continuous and non-destructive bioprocess that would preserve the root cultures.     

Leaf patterns,leaf size and ecologically related traits in high Mediterranean mountain on the Moroccan High Atlas

Leaf traits functional relationship is particularly important in plant ecological strategies, but few data are available from Mediterranean high-altitude environments. We analysed leaf general patterns and leaf trait relationships in 84 perennial species on the High Atlas, Morocco. We examined the correlation amongst leaf size, leaf width and length, plant height and seed size, analysed multi-trait relationships using Structural Equation Models and tested leaf size variation amongst growth forms (functional groups). Species spanned 10³ range of leaf size (sub-lepto- to microphylls). Nanophylls (48.8%) were dominant and over-represented in half-shrubs. Tree and rosette herbs were more likely to have large leaf size (nano-micro- and microphylls), whereas shrubs have medium leaf size (nano-micro- and nanophylls) and cushion and half-shrubs have small (sub-lepto- to nanophylls) and narrow leaves. Small-leaved species synchronized their leaf phenological activity with the dry summer months (May–August), and large-leaved species extended throughout the spring until the end of summer following the similar patterns found in lowland Mediterranean environments. Regarding woody species, our results showed a positive and significant relationship between leaf size and plant height and a non-significant relationship between leaf size and seed size. Structural Equation Models showed that variation in leaf size was triggered chiefly by changes in leaf form (leaf width) and plant height, seed size being of no relevance. In our study area, large-seeded species have a relatively wide range of leaf size. The hypothesis that the combination of large seeds and small leaves is allometrically unlikely (except for leptophyll Conifers) was supported in this study.     

Neurosteroid 3α-Androstanediol Efficiently Counteracts Paclitaxel-Induced Peripheral Neuropathy and Painful Symptoms

Painful peripheral neuropathy belongs to major side-effects limiting cancer chemotherapy. Paclitaxel, widely used to treat several cancers, induces neurological symptoms including burning pain, allodynia, hyperalgesia and numbness. Therefore, identification of drugs that may effectively counteract paclitaxel-induced neuropathic symptoms is crucial. Here, we combined histopathological, neurochemical, behavioral and electrophysiological methods to investigate the natural neurosteroid 3α-androstanediol (3α-DIOL) ability to counteract paclitaxel-evoked peripheral nerve tissue damages and neurological symptoms. Prophylactic or corrective 3α-DIOL treatment (4 mg/kg/2days) prevented or suppressed PAC-evoked heat-thermal hyperalgesia, cold-allodynia and mechanical allodynia/hyperalgesia, by reversing to normal, decreased thermal and mechanical pain thresholds of PAC-treated rats. Electrophysiological studies demonstrated that 3α-DIOL restored control values of nerve conduction velocity and action potential peak amplitude significantly altered by PAC-treatment. 3α-DIOL also repaired PAC-induced nerve damages by restoring normal neurofilament-200 level in peripheral axons and control amount of 2’,3’-cyclic-nucleotide-3’-phosphodiesterase in myelin sheaths. Decreased density of intraepidermal nerve fibers evoked by PAC-therapy was also counteracted by 3α-DIOL treatment. More importantly, 3α-DIOL beneficial effects were not sedation-dependent but resulted from its neuroprotective ability, nerve tissue repairing capacity and long-term analgesic action. Altogether, our results showing that 3α-DIOL efficiently counteracted PAC-evoked painful symptoms, also offer interesting possibilities to develop neurosteroid-based strategies against chemotherapy-induced peripheral neuropathy. This article shows that the prophylactic or corrective treatment with 3α-androstanediol prevents or suppresses PAC-evoked painful symptoms and peripheral nerve dysfunctions in rats. The data suggest that 3α-androstanediol-based therapy may constitute an efficient strategy to explore in humans for the eradication of chemotherapy-induced peripheral neuropathy.     

Maps of the Sri Lanka malaria situation preceding the tsunami and key aspects to be considered in the emergency phase and beyond

In Vietnam, a large proportion of all malaria cases and deaths occurs in the central mountainous and forested part of the country. Indeed, forest malaria, despite intensive control activities, is still a major problem which raises several questions about its dynamics. A large-scale malaria morbidity survey to measure malaria endemicity and identify important risk factors was carried out in 43 villages situated in a forested area of Ninh Thuan province, south central Vietnam. Four thousand three hundred and six randomly selected individuals, aged 10–60 years, participated in the survey. Rag Lays (86%), traditionally living in the forest and practising "slash and burn" cultivation represented the most common ethnic group. The overall parasite rate was 13.3% (range [0–42.3] while Plasmodium falciparum seroprevalence was 25.5% (range [2.1–75.6]). Mapping of these two variables showed a patchy distribution, suggesting that risk factors other than remoteness and forest proximity modulated the human-vector interactions. This was confirmed by the results of the multivariate-adjusted analysis, showing that forest work was a significant risk factor for malaria infection, further increased by staying in the forest overnight (OR= 2.86; 95%CI [1.62; 5.07]). Rag Lays had a higher risk of malaria infection, which inversely related to education level and socio-economic status. Women were less at risk than men (OR = 0.71; 95%CI [0.59; 0.86]), a possible consequence of different behaviour. This study confirms that malaria endemicity is still relatively high in this area and that the dynamics of transmission is constantly modulated by the behaviour of both humans and vectors. A well-targeted intervention reducing the "vector/forest worker" interaction, based on long-lasting insecticidal material, could be appropriate in this environment.     

Heterologous expression of bacteriocin E-760 in Chlamydomonas reinhardtii and functional analysis

The use of antimicrobial peptides (AMPs) synthesized by bacteria (bacteriocins) is an alternative for combating multidrug resistant bacterial strains and their production by recombinant route is a viable option for their mass production. The bacteriocin E-760 isolated from the genus Enterococcus sp. has been shown to possess inhibitory activity against Gram-negative and Gram-positive bacteria. In this study, the expression of a chimeric protein coding for E-760 in the nucleus of C. reinhardtii was evaluated, as well as, its antibacterial activity. The synthetic gene E-760S was inserted into the genome of C. reinhardtii using Agrobacterium tumefaciens. A transgenic line was identified in TAP medium with hygromycin and also by PCR. The increment in the culture medium temperature of the transgenic strain at 35 °C for 10 minutes, increased the production level of the recombinant protein from 0.14 (Noninduced culture, NIC) to 0.36% (Induced culture, IC) of total soluble proteins (TSP); this was quantified by an ELISA assay. Recombinant E-760 possesses activity against Staphylococcus aureus in 0.34 U log, Streptococcus agalactiae in 0.48 U log, Enterococcus faecium in 0.36 U log, Pseudomonas aeruginosa in 2 U log and for Klebsiella pneumoniae, the activity was 0.07 U log. These results demonstrate that the nucleus transformation of C. reinhardtii can function as a stable expression platform for the production of the synthetic gene E-760 and it can potentially be used as an antibacterial agent.     

Structural analysis and properties of dextran produced by Leuconostoc mesenteroides NRRL B-640

A water-soluble dextran was produced by purified dextransucrase from Leuconostoc mesenteroides NRRL B-640. The dextran was purified by alcohol precipitation. The structure of dextran was determined by FT-IR, ¹H NMR, ¹³C NMR and 2-dimensional NMR spectroscopic techniques. NMR techniques (1D ¹H, ¹³C and 2D HMQC) were used to fully assign the ¹H and ¹³C spectra. All the spectral data showed that the dextran contains d-glucose residues in a linear chain with consecutive α(1 → 6) linkages. No branching was observed in the dextran structure. The viscosity of dextran solution decreased with the increase in shear rate exhibiting a typical non-Newtonian pseudoplastic behavior. The surface morphology of dried and powdered dextran studied using Scanning electron microscopy revealed the cubical porous structure.     

Structure and functional expression of cloned rat serotonin 5HT-2 receptor.

A complementary DNA (cDNA) encoding a serotonin receptor with 51% sequence identity to the 5HT-1C subtype was isolated from a rat brain cDNA library by homology screening. Transient expression of the cloned cDNA in mammalian cells was used to establish the pharmacological profile of the encoded receptor polypeptide. Membranes from transfected cells showed high-affinity binding of the serotonin antagonists spiperone, ketanserin and mianserin, low affinity for haloperidol (a dopamine D2 receptor antagonist), 8-OH-DPAT as well as MDL-72222 and no detectable binding of [3H]serotonin. This profile is consonant with the 5HT-2 subtype of serotonin receptors. In agreement with this assignment, serotonin increased the intracellular Ca2+ concentration and activated phosphoinositide hydrolysis in transfected mammalian cells. The agonist also elicited a current flow, blocked by spiperone, in Xenopus oocytes injected with in vitro synthesized RNA containing the cloned nucleotide sequences.     

Investigation of lipid production by nitrogen-starved <Emphasis Type="Italic">Parachlorella kessleri</Emphasis> under continuous illumination and day/night cycles for biodiesel application

This study aims to investigate the triacylglycerol (TAG) productivity of Parachlorella kessleri grown under continuous illumination and to investigate its metabolism in simulated day/night cycles in order to estimate the feasibility of a large-scale production in outdoor solar photobioreactors. The strain was chosen for its ability to accumulate large amounts of triacylglycerol during nitrogen starvation. Several protocols of nitrogen starvation were tested in continuous illumination as well as in simulated day/night cycles. Sudden and progressive nitrogen starvation conditions have enhanced the TAG concentration and productivity of P. kessleri reaching up to 48 dry wt% and 4.4 × 10^?3 kg m^?2 day^?1, respectively. Microalgal cell metabolism was significantly affected by the day/night illumination cycles. The energy-rich compounds (TAGs and carbohydrates) were accumulated by P. kessleri during the photoperiods and partly consumed during the dark to sustain the microalgae vitality. This TAG oxidation ultimately led to a 26% decrease in TAG productivity in cultures exposed to day/night cycles compared to ones exposed to continuous illumination of equal 24-h average photon flux density. The results can dictate the optimal time for harvesting cells for recovering the largest amount of TAGs.