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21.

Background:

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is an infectious zoonotic pathogen causing human infections. These infections, in some cases, can lead to hemolytic uremic syndrome and its life-threatening complications and even death worldwide. The first intimate bacterial adhesion, intimin (I), with its own receptor translocated intimin receptor (Tir) and E. coli secreted protein A, acting as Tir conduit, are highly immunogenic proteins for vaccine development against E. coli O157:H7.

Methods:

A chimeric trivalent recombinant protein was previously found to be a suitable strategy for developing vaccines against E. coli O157:H7. In this study, the recombinant EIT (rEIT) was used to design a protective EHEC nasal nanovaccine. Chitosan and its water-soluble derivative, trimethylated chitosan (TMC), as muco-adhesive biopolymers, are good candidates for preparation of nanovaccines.  Using the electrospraying technique, as a novel method, we could obtain particles of rEIT loaded with chitosan and TMC on a nanometer scale. Mice were immunized with intranasal administration or intrapretoneal injection of rEIT.

Results:

The rEIT-specific immune responses (IgG and IgA) were measured by indirect ELISA. Only nasal administration of chitosan electrospray and TMC formulation produced significant secretion IgA. Intranasal administration of nanovaccine reduced the duration of bacterial fecal shedding on mice challenged with E. coli O157:H7.

Conclusion:

Since development of mucosal vaccines for the prevention of infectious diseases requires efficient antigen delivery; therefore, this research could be a new strategy for developing vaccine against E. coli O157:H7.Key Words: EnterohemorrhagicEscherichia coli, Nanoparticles, Intranasal vaccination  相似文献   
22.
This study examines the utility of measurements of canopy temperature depression (TD) below air temperature as an indirect selection criterion for grain yield in breeding of wheat ( Triticum aestivum L.). TD differences can be rapidly assessed using a hand-held infra-red thermometer and may reflect differences in stomatal conductance. Replicated small plot experiments were conducted with 23–24 spring wheat cultivars planted at two dates in the winter cropping cycles of 1991–92 and 1992–93 at a hot low latitude location in Mexico.
Across a two fold range in grain yield at each planting, TD was usually highly significantly correlated with grain yield. Averaging the results for each year, the phenotypic correlation TD vs. yield was 0.84** and 0.89** for 1991–92 and 1992–93, respectively. Correlations were strongest when TD was measured between noon and 4 pm, and were unaffected by crop stage of development (pre-heading, heading, grain fill) or timing relative to irrigation. TD was positively correlated with stomatal conductance. We discuss possible causes of these high correlations, and their implications for wheat breeding.  相似文献   
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24.
Assessment of the UV protecting potential of an aqueous methanol leaf extract of Harpephyllum caffrum proved that it possesses a distinct radical scavenging effect and inhibits the production of the proinflammatory cytokine IL-6 by human keratinocytes (HaCaT cells) following UV radiation. Phytochemical investigation of this extract led to isolation and structural determination of the hitherto unknown phenolics, kaempferol 3-O-(2″-sulphatogalactopyranoside), its quercetin analogue and 3-methoxyellagic acid 4-O-galactopyranoside in addition to 18 known phenolic compounds. The structures were determined by spectroscopic and conventional methods of analysis. Flavonoid sulphatoglycosides which have been rarely found in nature were major phenolic constituents of this plant, and this is the first report of the isolation of any of them from Anacardiaceae. The extract was found to diminish UV phototoxic reaction of keratinocytes. However, the isolated kaempferol sulphatogalactopyranoside did not interact with UVB triggered IL-6 production of HaCaT keratinocytes.  相似文献   
25.
Summary

Until recently, olive breeding programmes have been based exclusively on cultivated olive germplasm (Olea europaea subsp. europaea var. europaea), in contrast to breeding in other fruit crops where the use of wild relatives has been widely reported. In this study, ten agronomic traits were evaluated in two progenies derived from controlled crosses between the Spanish olive cultivar ‘Picual’ (female) and two wild (O. europaea subsp. europaea var. sylvestris) genotypes (males). The results of this evaluation were compared with the progenies of crosses between ‘Picual’ (female) and the three cultivars, ‘Sikitita’, ‘Meski’, and ‘Zaity’ (male). The two ‘Picual’ × wild genotype progenies had the highest mean values for vigour traits (i.e., tree height and trunk diameter). Progenies from both ‘Picual’ × wild genotype crossess also showed the highest percentages of trees (53.8% and 37.5%) with a short juvenile period, compared to the progenies from crosses between ‘Picual’ and each of the three cultivars ‘Sikitita’, ‘Meski’, and ‘Zaity’ (0%, 5%, and 3.6%, respectively). Significant differences were also observed between progenies in fruit traits as well as in oil contents and fruit weights. Progenies from both crosses with wild olive showed lower values for the fruit traits evaluated than the cultivated olive progenies. However, significant improvements were achieved compared to fruit traits in the wild parents. The implications of these results for the future use of wild germplasm in olive breeding programmes are discussed.  相似文献   
26.
Microplastics (MPs) in sediments from the complex lagoon-channel of Bizerte were investigated, for the first time, to evaluate the occurrence and abundance of MPs in Tunisia. After density separation in saline solution, MPs were counted by a stereomicroscope. The number of MPs was at the range of 3–18 items/g sediment (3000–18,000 items/kg dry sediment) and the most contaminated site was of Menzel Abderrahmane (MA) followed by Carrier Bay (CB), Menzel Jemil (MJ) and Channel of Bizerte (C). The MPs gathered during the survey varied in size from 0.3 to 5 mm, and appear in a variety of shapes and colours. The dominant shape was fibre (88.88% in MA, 91.00% in CB, 82.35% in C and 21.05% in MJ). The rest of MPs are fragments whilst no micro beads were found. Colours are clear, white, blue, green, red and black. Cities discharges, fishing activity and industrial production sites are the most likely sources of MPs. This first work provides original data on the presence of MPs that determines their bioavailability to organisms as seafood, and then possibly transfers of to human. The high MP concentrations registered in the complex lagoon-channel of Bizerte suggest that this site is a hotspot for MP pollution and there is an urgency to understand their origins and effects on marine life. The results will provide useful background information for further investigations.  相似文献   
27.
The use of Village Participatory Land Use Plan (VPLUP) model as a natural resource management and conservation tool has been growing recently. This study examined the premise under which VPLUPs implementation can enhance the management and conservation of Village Land Forest Reserves (VLFRs) in the context of Reduced Emissions from Deforestation and forest Degradation plus (REDD+) initiative in the Kilosa district of Tanzania. A mixed method research design, which integrates participatory community mapping (PCM), focus group discussions (FGDs), key informants interviews (KIIs), direct observations, and household interviews were used in data collection. The results showed that there were significant (p < 0.05) improvements in forest management and conservation indicators after VPLUPs implementation, and increase in the management and conservation activities carried out by the community after the implementation of VPLUPs. There was also a significant decrease (p < 0.05) in almost all uses of the forest after the implementation of VPLUPs. The findings provide evidence that the VPLUP model has potential for enhancing the management and conservation of forests in the context of REDD+ strategy. Thus, it is argued that VPLUP can be used as a forest management and conservation tool to facilitate the implementation of the REDD+ initiatives.  相似文献   
28.
Ambrosia beetles, including Platypus cylindrus, commonly act as vectors of Ophiostomatales. In an investigation of fungi associated with P. cylindrus, several species of Ophiostomatales were identified, including two species of Ophiostoma s. str. These two species were characterized based on comparisons of DNA sequences of the internal transcribed spacer regions including the 5.8S gene of rDNA and β‐tubulin gene. Two distinct clades were discernable in the phylogenetic trees, supported by high bootstrap values. One clade included the species Ophiostoma tsotsi, reported herein for the first time in Tunisia, and the species Ophiostoma quercus.  相似文献   
29.
The effect of dietary mannan oligosaccharide (MOS; activeMOS®) on growth, survival, and body composition in giant sturgeon juvenile (Huso huso) with initially average weight 46.89 ± 2.57 was investigated for a period of 46 days. Basal diet were supplemented with 0 (control), 2, and 4 g kg?1 MOS in a totally randomized design trial in triplicate groups. The results showed no significant differences in growth and feeding parameters between control and treatment groups (MOS supplementation diets) (P > 0.05). There was a statistically significant decrease (P < 0.05) in feed per fish level in only group treated with 4 g kg?1 MOS. The highest and the lowest growth performances were observed in 2 and 4 g kg?1 MOS, respectively. There were no significant differences in survival rate among all treatment groups (P > 0.05). In group treated with 2 g kg?1 MOS was a significant difference in lipid carcass (P < 0.05), whereas protein, ash, and moisture remained unaffected (P > 0.05). However, no significant difference was observed in intestinal lactic acid bacteria between all treatment groups (P > 0.05). There were no significant differences in hematological parameters between control and MOS treatment groups (P > 0.05). These results suggested that the prebiotic mannan oligosaccharide did not influence the growth performance in giant sturgeon juvenile, and it is not appropriate for supplementation in the diet of cultured juvenile giant sturgeon.  相似文献   
30.
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