Relaxant effect of aqueous extract of Cistus ladaniferus on rodent intestinal contractions

The effects of the aqueous extract of Cistus ladaniferus leaves and stems were studied on the rodent isolated jejunum. The extract produced a reversible concentration dose-dependent (0.1-3 mg/ml) inhibition of the spontaneous motility of the rabbit jejunum. The inhibitory effects of the extract were not affected by pretreatment with the inhibitors of the alpha and beta adrenergic receptors yohimbine, prazosin or propranolol. The extract also inhibited K(+)-induced contractions in rabbit and rat jejunum at a similar concentration range. This result suggests that the antispasmodic action of the extract is mediated through calcium channel blockade. The results confirm the traditional use of C. ladaniferus in treating intestinal ache.     

Mining the genetic diversity of Ehrlichia ruminantium using map genes family

Understanding bacterial genetic diversity is crucial to comprehend pathogenesis. Ehrlichia ruminantium (E. ruminantium), a tick-transmitted intracellular bacterial pathogen, causes heartwater disease in ruminants. This model rickettsia, whose genome has been recently sequenced, is restricted to neutrophils and reticulo-endothelial cells of its mammalian host and to the midgut and salivary glands of its vector tick. E. ruminantium harbors a multigene family encoding for 16 outer membrane proteins including MAP1, a major antigenic protein. All the 16 map paralogs are expressed in bovine endothelial cells and some are specifically translated in the tick or in the mammalian host.In this study, we carried out phylogenetic analyses of E. ruminantium using sequences of 6 MAP proteins, MAP1, MAP1-2, MAP1-6, MAP1-5, MAP1+1 and MAP1-14, localized either in the center or at the borders of the map genes cluster.We show that (i) map1 gene is a good tool to characterize the genetic diversity among Africa, Caribbean islands and Madagascar strains including new emerging isolates of E. ruminantium; (ii) the different map paralogs define different genotypes showing divergent evolution; (iii) there is no correlation between all MAP genotypes and the geographic origins of the strains; (iv) The genetic diversity revealed by MAP proteins is conserved whatever is the scale of strains sampling (village, region, continent) and thus was not related to the different timing of strains introduction, i.e. continuous introduction of strains versus punctual introduction (Africa versus Caribbean islands).These results provide therefore a significant advance towards the management of E. ruminantium diversity. The differential evolution of these paralogs suggests specific roles of these proteins in host–vector–pathogen interactions that could be crucial for developing broad-spectrum vaccines.     

Complementary responses between hydrolyzed feather meal,fish meal and soybean meal without amino acid supplementation in Nile tilapia Oreochromis niloticus diets

The purpose of this study was to evaluate hydrolyzed feather meal (HFM) as a substitute for fish meal (FM) or soybean meal (SBM) in Nile tilapia fry diets. Triplicate groups of fish (initial body weight 2.30 g ± 0.01) were fed seven isonitrogenous and isocaloric diets formulated to contain 30 % crude protein and 19.70 kJ g^?1 gross energy for 8 weeks. The control diet (CD) contained 22 % local FM and 30 % SBM, whereas in the other six diets, HFM replaced 33, 66 or 100 % of FM or SBM. The best weight gain (11.46), specific growth rate (3.14) and feed conversion ratio (1.24) of tilapia fry fed SBM_33%, CD, FM_33% and SBM_66% diets were exhibited. Final body weight and protein retention increased in a linear pattern with increasing amino acids in the experimental diets with the exception of leucine and valine. The results indicated that good-quality HFM can successfully replace FM or SBM by up to 33 and 66 %, respectively, in Nile tilapia fry diets without compromising growth and protein utilization. The results also support the benefits of combining different sources of plant and animal proteins in Nile tilapia diets.     

Seroprevalence of Neospora caninum antibodies and its consequences for reproductive parameters in dairy cows from Dakar–Senegal,West Africa

The aim of this study was to determine the seroprevalence of Neospora caninum antibodies and its effects on reproductive parameters in cows in intensive dairy herds in Dakar. Randomised blood samples were taken for serology from 196 cows in four herds with a history of sporadic abortion. All of the sera were assayed for antibodies against N. caninum, Candida guillermondii, Coxiella burnetii, and Chlamydophila sp. The associations between serostatus and reproductive parameters (abortion, number of inseminations to conception, and calving to conception interval) were assessed over a period of 5 years (2004–2008). The seroprevalence of N. caninum antibodies in dairy cattle was 17.9%. The local Gobra breed and crossbreeds had higher levels of N. caninum antibodies than exotic breeds (p < 0.05). For the most recent pregnancies, seropositive cows required more inseminations to establish conception than seronegative cows (p < 0.05). The results indicate that dairy cattle from Dakar are exposed to N. caninum. Neosporosis should, therefore, be systematically considered as a cause when the calving to conception interval is prolonged.     

New Metabolites from the Marine Sponge Scopalina hapalia Collected in Mayotte Lagoon

The biological screening of 44 marine sponge extracts for the research of bioactive molecules, with potential application in the treatment of age-related diseases (cancer and Alzheimer’s disease) and skin aging, resulted in the selection of Scopalina hapalia extract for chemical study. As no reports of secondary metabolites of S. hapalia were found in the literature, we undertook this research to further extend current knowledge of Scopalina chemistry. The investigation of this species led to the discovery of four new compounds: two butenolides sinularone J (1) and sinularone K (2), one phospholipid 1-O-octadecyl-2-pentanoyl-sn-glycero-3-phosphocholine (3) and one lysophospholipid 1-O-(3-methoxy-tetradecanoyl)-sn-glycero-3-phosphocholine (4) alongside with known lysophospholipids (5 and 6), alkylglycerols (7–10), epidioxysterols (11 and 12) and diketopiperazines (13 and 14). The structure elucidation of the new metabolites (1–4) was determined by detailed spectroscopic analysis, including 1D and 2D NMR as well as mass spectrometry. Molecular networking was also explored to complement classical investigation and unravel the chemical classes within this species. GNPS analysis provided further information on potential metabolites with additional bioactive natural compounds predicted.     

Antimicrobial and Antibiofilm Activities of the Fungal Metabolites Isolated from the Marine Endophytes Epicoccum nigrum M13 and Alternaria alternata 13A

Epicotripeptin (1), a new cyclic tripeptide along with four known cyclic dipeptides (2–5) and one acetamide derivative (6) were isolated from seagrass-associated endophytic fungus Epicoccum nigrum M13 recovered from the Red Sea. Additionally, two new compounds, cyclodidepsipeptide phragamide A (7) and trioxobutanamide derivative phragamide B (8), together with eight known compounds (9–16), were isolated from plant-derived endophyte Alternaria alternata 13A collected from a saline lake of Wadi El Natrun depression in the Sahara Desert. The structures of the isolated compounds were determined based on the 1D and 2D NMR spectroscopic data, HRESIMS data, and a comparison with the reported literature. The absolute configurations of 1 and 7 were established by advanced Marfey’s and Mosher’s ester analyses. The antimicrobial screening indicated that seven of the tested compounds exhibited considerable (MIC range of 2.5–5 µg/mL) to moderate (10–20 µg/mL) antibacterial effect against the tested Gram-positive strains and moderate to weak (10–30 µg/mL) antibacterial effect against Gram-negative strains. Most of the compounds exhibited weak or no activity against the tested Gram-negative strains. On the other hand, four of the tested compounds showed considerable antibiofilm effects against biofilm forming Gram-positive and Gram-negative strains.     

Antihyperglycemic activity of the aqueous extract of Urtica dioica

When administered 30 min before glucose loading, the aqueous extract of Urtica dioica (nettle) (250 mg/kg) showed a strong glucose lowering effect. The decrease of glycemia has reached to 33+/-3.4% of the control value 1 h after glucose loading. This effect was persistent during 3 h. In contrast, nettle did not show hypoglycemic effect in alloxan-induced diabetic rats. The amount of glucose absorbed in a segment jejunum in situ was 8.05+/-0.68 mg in presence of nettle extract vs. 11.11+/-0.75 mg in control rats during 2 h (P<0.05). The results indicate that nettle has a significant antihyperglycemic effect in OGTT model. This effect may be caused in part by the reduction of intestinal glucose absorption. LD(50) is 3.5 g/kg (i.p.).     

Structural basis of energy transduction in the transport cycle of MsbA

We used site-directed spin-labeling and electron paramagnetic resonance spectroscopy to characterize the conformational motion that couples energy expenditure to substrate translocation in the multidrug transporter MsbA. In liposomes, ligand-free MsbA samples conformations that depart from the crystal structures, including looser packing and water penetration along the periplasmic side. Adenosine triphosphate (ATP) binding closes the substrate chamber to the cytoplasm while increasing hydration at the periplasmic side, consistent with an alternating access model. Accentuated by ATP hydrolysis, the changes in the chamber dielectric environment and its geometry provide the likely driving force for flipping amphipathic substrates and a potential exit pathway. These results establish the structural dynamic basis of the power stroke in multidrug-resistant ATP-binding cassette (MDR ABC) transporters.     

Antiviral activities of sulfated polysaccharides isolated from Sphaerococcus coronopifolius (Rhodophytha, Gigartinales) and Boergeseniella thuyoides (Rhodophyta, Ceramiales)

Water-soluble sulfated polysaccharides isolated from two red algae Sphaerococcus coronopifolius (Gigartinales, Sphaerococcaceae) and Boergeseniella thuyoides (Ceramiales, Rhodomelaceae) collected on the coast of Morocco inhibited in vitro replication of the Human Immunodeficiency Virus (HIV) at 12.5 μg/mL. In addition, polysaccharides were capable of inhibiting the in vitro replication of Herpes simplex virus type 1 (HSV-1) on Vero cells values of EC₅₀ of 4.1 and 17.2 μg/mL, respectively. The adsorption step of HSV-1 to the host cell seems to be the specific target for polysaccharide action. While for HIV-1, these results suggest a direct inhibitory effect on HIV-1 replication by controlling the appearance of the new generations of virus and potential virucidal effect. The polysaccharides from S. coronopifolius (PSC) and B. thuyoides (PBT) were composed of galactose, 3,6-anhydrogalactose, uronics acids, sulfate in ratios of 33.1, 11.0, 7.7 and 24.0% (w/w) and 25.4, 16.0, 3.2, 7.6% (w/w), respectively.