Chemical Composition and Antimicrobial Activity of Essential Oils from Scabiosa arenaria Forssk. Growing Wild in Tunisia

The essential oils isolated from three organs, i.e., fruits, stems and leaves, and flowers, of the endemic North African plant Scabiosa arenaria Forssk . were screened for their chemical composition, as well as their possible antibacterial, anticandidal, and antifungal properties. According to the GC‐FID and GC/MS analyses, 61 (99.26% of the total oil composition), 79 (98.43%), and 51 compounds (99.9%) were identified in the three oils, respectively. While α‐thujone (34.39%), camphor (17.48%), and β‐thujone (15.29%) constituted the major compounds of the fruit oil, chrysanthenone (23.43%), together with camphor (12.98%) and α‐thujone (10.7%), were the main constituents of the stem and leaf oil. In the case of the flower oil, also chrysanthenone (38.52%), camphor (11.75%), and α‐thujone (9.5%) were identified as the major compounds. Furthermore, the isolated oils were tested against 16 Gram‐positive and Gram‐negative bacteria, four Candida species, and nine phytopathogenic fungal strains. It was found that the oils exhibited interesting antibacterial and anticandidal activities, comparable to those of thymol, which was used as positive control, but no activity against the phytopathogenic fungal strains was observed.     

Ultrastructural study of the male gamete of Pleurogonius truncatus Prudhoe, 1944 (Platyhelminthes, Digenea, Pronocephalidae) parasite of Eretmochelys imbricata (Linnaeus, 1766)

In Pronocephaloidea, the spermatozoa of only two species have been studied today. Because of this, we present in this work data concerning to a third specie, Pleurogonius truncatus Prudhoe, 1944. The mature spermatozoon of P. truncatus possesses two axonemes with the 9+"1" pattern typical of Trepaxonemata, mitochondrion, nucleus, parallel cortical microtubules, spinelike bodies, cytoplasmic expansion and an external ornamentation of the plasma membrane. A particularity of the spermatozoon of P. truncatus is in the ultrastructure of the anterior spermatozoon extremity with only cortical microtubules and ornamentation of the plasma membrane. This type of anterior extremity has never been described until today in Pronocephaloidea. On the other hand, the ultrastructure of the posterior extremity of the spermatozoon confirms that already described in Pronocephalidae.     

Multispacer sequence typing relapsing fever Borreliae in Africa

Background

In Africa, relapsing fevers are neglected arthropod-borne infections caused by closely related Borrelia species. They cause mild to deadly undifferentiated fever particularly severe in pregnant women. Lack of a tool to genotype these Borrelia organisms limits knowledge regarding their reservoirs and their epidemiology.

Methodology/Principal Findings

Genome sequence analysis of Borrelia crocidurae, Borrelia duttonii and Borrelia recurrentis yielded 5 intergenic spacers scattered between 10 chromosomal genes that were incorporated into a multispacer sequence typing (MST) approach. Sequencing these spacers directly from human blood specimens previously found to be infected by B. recurrentis (30 specimens), B. duttonii (17 specimens) and B. crocidurae (13 specimens) resolved these 60 strains and the 3 type strains into 13 species-specific spacer types in the presence of negative controls. B. crocidurae comprised of 8 spacer types, B. duttonii of 3 spacer types and B. recurrentis of 2 spacer types.

Conclusions/Significance

Phylogenetic analyses of MST data suggested that B. duttonii, B. crocidurae and B. recurrentis are variants of a unique ancestral Borrelia species. MST proved to be a suitable approach for identifying and genotyping relapsing fever borreliae in Africa. It could be applied to both vectors and clinical specimens.     

Landscape ecology of sylvatic chikungunya virus and mosquito vectors in southeastern Senegal

The risk of human infection with sylvatic chikungunya (CHIKV) virus was assessed in a focus of sylvatic arbovirus circulation in Senegal by investigating distribution and abundance of anthropophilic Aedes mosquitoes, as well as the abundance and distribution of CHIKV in these mosquitoes. A 1650 km(2) area was classified into five land cover classes: forest, barren, savanna, agriculture and village. A total of 39,799 mosquitoes was sampled from all classes using human landing collections between June 2009 and January 2010. Mosquito diversity was extremely high, and overall vector abundance peaked at the start of the rainy season. CHIKV was detected in 42 mosquito pools. Our data suggest that Aedes furcifer, which occurred abundantly in all land cover classes and landed frequently on humans in villages outside of houses, is probably the major bridge vector responsible for the spillover of sylvatic CHIKV to humans.     

Classification des stades de sommeil par des réseaux de neurones artificiels hiérarchiques

The goal of our work is to provide an automatic analysis and decision tool for sleep stages classification based on an artificial neural networks (ANN). The first difficulty lies in choosing the physiological signals representation and in particular the electroencephalogram (EEG). Once the representation adopted, the next step is to design the optimal neural network determined by a learning and validation process of data from a set of sleep records. We studied several configurations of conventional ANN giving results varying from 62 to 71 %, then we proposed a new hierarchical configuration, which gives a rate of 74 % correct classification for six stages. These results lead us to further explore this issue at the representation and design of ANNs to improve the performance of our tool.     

No Difference in the Incidence of Malaria in Human-Landing Mosquito Catch Collectors and Non-Collectors in a Senegalese Village with Endemic Malaria

BackgroundThe human landing catches is the gold standard method used to study the vectors of malaria and to estimate their aggressiveness. However, this method has raised safety concerns due to a possible increased risk of malaria or other mosquito-borne diseases among the mosquito collectors. The aim of this study was to evaluate the incidence of malaria attacks among mosquito collectors and to compare these results with those of non-collectors in a Senegalese village.MethodsFrom July 1990 to December 2011, a longitudinal malaria study involving mosquito collectors and non-collectors was performed in Dielmo village, Senegal. During the study period, 4 drugs were successively used to treat clinical malaria, and long-lasting insecticide-treated nets were offered to all villagers in July 2008. No malaria chemoprophylaxis was given to mosquito collectors. Incidence of uncomplicated clinical malaria and asymptomatic malaria infection were analyzed among these two groups while controlling for confounding factors associated with malaria risk in random effects negative binomial and logistic regression models, respectively.ResultsA total of 3,812 person-trimester observations of 199 adults at least 15 years of age were analyzed. Clinical malaria attacks accounted for 6.3% both in collectors and non-collectors, and asymptomatic malaria infections accounted for 21% and 20% in collectors and non-collectors, respectively. A non-significant lower risk of malaria was observed in the collector group in comparison with the non-collector group after adjusting for other risk factors of malaria and endemicity level (Clinical malaria: adjusted incidence rate ratio = 0.89; 95% confidence interval = 0.65-1.22; p= 0.47).ConclusionBeing a mosquito collector in Dielmo was not significantly associated with an increased risk of malaria both under holoendemic, mesoendemic and hypoendemic conditions of malaria epidemiology. This result supports the view that HLC, the most accurate method for evaluating malaria transmission, may be used without health concerns in Dielmo.     

Involvement of Zn Depletion in Cd-Induced Toxicity on Prenatal Bone Formation in Rat

This experiment was conducted to evaluate the effects of chromium methionine with/without zinc sulfate or zinc amino acid complex on the growth performance, carcass traits, meat quality, serum parameters, endocrine parameters, and antioxidant status of growing-finishing pigs. A total of 180 (32.0 ± 1.7 kg body weight, BW) crossbred pigs (Duroc × Landrace × Yorkshire) were used in a completely randomized design with three dietary treatments and 10 replicates per treatment (five pens of barrows and five pens of gilts with six pigs per replicate). Three treatments were corn-soybean meal-based diets supplemented with 100 mg Zn/kg from zinc sulfate (ZnSO₄), 100 mg Zn/kg from ZnSO₄ + 0.2 mg Cr/kg from chromium methionine complex (CrMet), or 50 mg Zn/kg from ZnSO₄ + 50 mg Zn/kg from zinc amino acid complex (ZnAA) + 0.2 mg Cr/kg from CrMet, respectively. The experiment lasted 105 days, of which was divided into three stages including phase 1 (30 to 50 kg BW), phase 2 (50 to 80 kg BW), and phase 3 (80 to 110 kg BW). Results showed that supplementation with CrMet and ZnAA improved (P < 0.05) the feed conversion of the pigs in phase 2, phase 3, and the overall experiment. Hot carcass weight, dressing percentage, and a longissimus dorsi muscle area were increased (P < 0.05) in pigs fed with diets supplemented with both CrMet and ZnAA compared with pigs fed with diets containing only ZnSO₄ (P < 0.05). There was also an increase (P < 0.01) pH_24 h in the longissimus dorsi muscle in pigs fed with diets supplemented with CrMet and ZnAA. The concentration of serum glucose in pigs fed with diets containing CrMet and ZnAA was decreased (P < 0.05) compared with that in pigs fed with the diet containing ZnSO₄. Supplementation with CrMet and ZnAA increased (P < 0.05) the circulating levels of insulin and decreased (P < 0.05) cortisol. There was an increase (P < 0.05) in total serum antioxidant capacity and Cu/Zn superoxide dismutase activity as well as a decrease (P < 0.05) in serum malondialdehyde concentrations in pigs fed with diets supplemented with CrMet and ZnAA compared with pigs fed with the diet supplemented only with ZnSO₄. In conclusion, supplementation of CrMet only or CrMet together with ZnAA improved feed conversion, carcass traits, and meat quality in the growing-finishing pigs.     

Effect of temperature on the performance of an anaerobic tubular reactor treating fruit and vegetable waste

This study compares the performance of anaerobic digestion of fruit and vegetable waste (FVW) in the thermophilic (55 °C) process with those under psychrophilic (20 °C) and mesophilic (35 °C) conditions in a tubular anaerobic digesters on a laboratory scale. The hydraulic retention time (HRT) ranged from 10 to 20 days, and raw fruit and vegetable waste was supplied in a semi-continuous mode at various concentrations of total solids (TS) (4, 6, 8 and 10% on dry weight). Biogas production from the experimental thermophilic digester was higher on average than from psychrophilic and mesophilic digesters by 144 and 41%, respectively. The net energy production in the thermophilic digester was 195.7 and 49.07 kJ per day higher than that for the psychrophilic and mesophilic digesters, respectively. The relation between the daily production of biogas and the temperature indicates that for the same produced quantity of biogas, the size of the thermophilic digester can be reduced with regard to that of the psychrophilic and the mesophilic digesters.     

Antimicrobial and antioxidant activities of methanol extracts of <Emphasis Type="Italic">Evax pygmaea</Emphasis> (Asteraceae) growing wild in Tunisia

Antimicrobial activity of methanolic extracts obtained from the aerial parts of Evax pygmaea was tested against five bacteria and two strains of phytopathogenic fungi using the agar diffusion and broth microdilution methods. Antioxidant properties were evaluated through the ability of the different fractions to scavenge the stable ABTS (2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)) and DPPH (1,1-diphenyl-2-picrylhydrazyl) radicals. The TEAC (Trolox Equivalent Antioxidant Capacity) and IC₅₀ values of the fractions were calculated and compared. The experimental data indicated that all fractions exhibit moderate to appreciable antibacterial activities against all Gram-positive cocci and Gram-negative rods except Pseudomonas aeruginosa, but no antifungal activity was observed. Ethyl acetate and methanol fractions were found to cause significant free radical-scavenging effects in both assays. These results may suggest that E. pygmaea could be used as a natural preservative ingredient in the food and/or pharmaceutical industries.