Synthetic seed production by encapsulating nodal segment of <Emphasis Type="Italic">Capparis decidua</Emphasis> (Forsk.), in vitro regrowth of plantlets and their physio biochemical studies

Synthetic seed technology is an emerging and broadly used technique in the field of plant biotechnology to conserve economically important plants. In the present study, nodal segments of Capparis decidua were entrapped in calcium alginate gel matrix to produce firm and uniform synthetic seeds. 3% sodium alginate and 75 mM calcium chloride were found best for encapsulation. Among all the concentrations and combinations of thidiazuron (TDZ) either singly or with indole -3- acetic acid (IAA) augmented in Murashige and Skoog medium used, TDZ (5.0 µM) + IAA (0.5 µM) was found most effective in conversion of synthetic seeds into plantlets as 79% plantlets were developed on this combination with 13.2 ± 0.87 shoots and 5.5 ± 0.40 cm shoot length after 8 weeks of culture. Further, synthetic seeds stored at low temperature (4 °C) can retain their viability up to 4 weeks and showed maximum conversion rate (93%) into plantlets, when placed back to regeneration medium. Root formation was also occurred in the same regeneration medium and roots were healthy. Plantlets were successfully hardened in culture room in plastic cups filled with sterile vermiculite and after 4 weeks, they were transferred to greenhouse where they exhibited normal growth with 80% survival. Growth parameters were evaluated in micropropagated plants and compared with the seedlings of same age. Effect of different days of acclimatization were also recorded on various physio-biochemical activities and showed a positive response that can be interpreted as better protection mechanism of micropropagated plants against the stress possibly generated due to reactive oxygen species when transferred to ex vitro environment.     

In vitro destruction of Eimeria oocysts by essential oils

This study aims to assess the ability of essential oils (EOs) to destroy Eimeria oocyst in vitro using microscopic counting and 273 nm absorbing material release. A screening for the ability of ten EOs to destroy Eimeria oocyst was carried out in liquid medium. Out of these ten, artemisia, tea tree, thyme and clove EOs were identified as being the most effective. The treatment of Eimeria oocyst with these EOs leads to their lysis as shown by the release of substances absorbing at 273 nm. These results were obtained after approximately three hours contact. Four EOs were proven to destroy Eimeria oocysts in a few hours at low concentration. This destructive effect is a consequence of their lysis. This work is a preliminary contribution aiming to develop a new generation of natural efficient agents for destroying Eimeria oocyst to fight coccidiosis in broiler chicken.     

A comparison of dairy cattle systems in an irrigated perimeter and in a suburban region: case study from Morocco

Multivariate analyses were used to compare dairy production practices and their consequences on milk yield and profitability in cattle farms from two representative regions of Morocco. A regular follow-up of 118 farms (48 in the Rabat-Salé suburban belt and 70 in the Gharb irrigated perimeter) was undertaken to obtain accurate data. Results show significant differences between the two regions. Intensive milk production was more frequent in the suburban zone (more concentrates and better annual milk yield per cow). When conducting a “within-region” principal components analysis, farms’ discrimination appeared to take into account all management variables (feeding, cattle sales, profitability), with no reference to farms’ structural parameters (arable land and number of cattle). A typology of farms was then established using cluster analysis, with 4 distinct groups, namely: a) concentrates wasters, b) farms with a relatively important milk yield per cow, c) deficit dairy farms and d) beef oriented farms. The last group included almost exclusively farms from the irrigated perimeter (5 out of 7). These results indicate that dairy production promotion in Morocco requires more than just the intensification of forage production, but should focus also on improving management practices. The extension of complete and balanced dairy rations is urgently needed to enhance milk yield and profitability.     

Micromorphology of periglacial sediments from the Tayara site,Qikirtaq Island,Nunavik (Canada)

Soil micromorphology provides an excellent resource for investigating Palaeoeskimo site-formation processes in the low arctic periglacial environment. In this study, micromorphology was used to answer questions concerning the composition, structure, origin and depositional agencies of the Tayara site active layer's sediments as well as to distinguish between natural (geogenic, biopedogenic) and cultural (anthropogenic) processes. Five groups of microfeatures were documented. These include 1) biopedological features (soil organic matter accumulation, mesofaunal and fungal activities), 2) transport-inherited features related to depositional processes (solifluction and stream sedimentation), 3) frost-induced microstructures and cryogenic features such as major post-depositional changes (ice-segregation, particle rearrangement, frost shattering, cryoturbation), 4) bone preservation in the active layer at the microscopic level, and 5) anthropogenic features related to Palaeoeskimo activities. The sediments from the three archaeological levels (I, IA and II) appear to have been very little influenced by anthropogenic factors. Cultural processes are micromorphologically observed in level II, with some evidence of feeding (bone presence), burning (wood charcoal, heated bone), and possibly trampling. However, the effects of natural processes on the sediments are more pronounced than anthropogenic ones.     

Contributions of indigenous arbuscular mycorrhizal fungi to growth of retama monosperma and acacia gummifera under water stress (case study: essaouira sand dunes forest)

ABSTRACT

Two leguminous plant species: Retama monosperma and Acacia gummifera were selected for water deficit tolerance test for future use in reforestation programs of the Atlantic sand dunes forest of Essaouira region. Mycorrhizal fungal colonization was used to help plants amend the water deficit. To assess R. monosperma and A. gummifera response to water stress and the effectiveness of mycorrhizal formation alleviating it, two categories for each plant species were made, one inoculated with mycorrhizal fungi and the other not, were submitted to a hydric deficit treatment of four levels for 6 months. This treatment impact on the plants was assessed by comparing root/shoot dry weight ratios, levels of nitrogen and phosphorus, and by measuring mycorrhizal colonization frequencies and intensities. Results showed that these parameters were significantly affected by water deficit. The presence of the mycorrhizal fungi had significantly enhanced plants phosphorus uptake by 72–124% for Acacia gummifera and 87–161% for Retama monosperma. Nitrogen uptake was increased by 134–388% for Retama monosperma and 510–901% for Acacia gummifera. The colonization frequencies changed significantly only for the treatment extreme level and stayed between 80%-90% for the other levels. The mycorrhization intensities showed significant lessening between each treatment level decreasing from 35% to 10%.     

Monitoring of sewage pollution in the surface sediments of coastal ecosystems using linear alkylbenzenes (LABs) as molecular markers

Journal of Soils and Sediments - Molecular organic markers are an effective tool to detect the adverse effects of anthropogenic inputs in the aquatic environment. Linear alkylbenzenes (LABs) are...     

Stable isotope dilution techniques for assessing vitamin A status and bioefficacy of provitamin A carotenoids in humans

Vitamin A deficiency is a major global public health problem. Among the variety of techniques that are available for assessing human vitamin A status, evaluating the provitamin A nutritional values of foodstuffs and estimating human vitamin A requirements, isotope dilution provides the most accurate estimates. Although the relative expense of isotope dilution restricts its applications, it has an important function as the standard of reference for other techniques. Mathematical modelling plays an indispensable role in the interpretation of isotope dilution data. This review summarises recent applications of stable isotope methodology to determine human vitamin A status, estimate human vitamin A requirements, and calculate the bioconversion and bioefficacy of food carotenoids.     

Characterization of Erwinia amylovora strains from Middle Atlas Mountains in Morocco by PCR based on tandem repeat sequences

Forty Erwinia amylovora strains isolated from the Middle Atlas Mountains in Morocco have been characterized using sequences from tandem repeat of variable numbers (VNTR) as chromosomal markers. Three VNTR sequences were identified and used for studying the genetic diversity of the strains using a PCR fingerprinting method. Thirty nine strains showed high genetic homogeneity, but one strain displayed a profile quite different. We were able to obtain reproducible and characteristic profiles in strains from remote geographical areas, and associated them with each of the primers. Comparative analyses of Moroccan strains with three reference strains from Spain, France and England, were performed. The results revealed some polymorphisms compared with the English and the French strains, but notable similarities were observed with a Spanish strain obtained from plants imported from Belgium. The developed methodology has demonstrated its usefulness for being applied in epidemiological studies.     

The Marek��s disease virus (MDV) protein encoded by the UL17 ortholog is essential for virus growth

Marek’s disease virus type 1 (MDV-1) shows a strict dependency on the direct cell-to-cell spread for its propagation in cell culture. As MDV-1 shows an impaired nuclear egress in cell culture, we wished to address the characterization of capsid/tegument genes which may intervene in the maturation of intranuclear capsids. Orthologs of UL17 are present in all herpesviruses and, in all reported case, were shown to be essential for viral growth, playing a role in capsid maturation and DNA packaging. As only HSV-1 and PrV UL17 proteins have been characterized so far, we wished to examine the role of MDV-1 pUL17 in virus replication. To analyze MDV-1 UL17 gene function, we created deletion mutants or point mutated the open reading frame (ORF) to interrupt its coding phase. We established that a functional ORF UL17 is indispensable for MDV-1 growth. We chose to characterize the virally encoded protein by tagging the 729 amino-acid long protein with a repeat of the HA peptide that was fused to its C-terminus. Protein pUL17 was identified in infected cell extracts as an 82 kDa protein which localized to the nucleus, colocalizing with VP5, the major capsid protein, and VP13/14, a major tegument protein. By using green fluorescent protein fusion and HA tagged proteins expressed under the cytomegalovirus IE gene enhancer/promoter (P_{CMV IE}), we showed that MDV-1 pUL17 nuclear distribution in infected cells is not an intrinsic property. Although our results strongly suggest that another viral protein retains (or relocate) pUL17 to the nucleus, we report that none of the tegument protein tested so far were able to mediate pUL17 relocation to the nucleus.