Evaluation of glycoproteins purified from adult and larval camel ticks (Hyalomma dromedarii) as a candidate vaccine

In order to identify antigens that can help prevent camel tick infestations, three major glycoproteins (GLPs) about 97, 66 and 40 kDa in size were purified from adult and larval Egyptian ticks, Hyalomma (H.) dromedarii, using a single-step purification method with Con-A sepharose. The purified GLPs were evaluated as vaccines against camel tick infestation in rabbits. The rabbits received three intramuscular inoculations of GLPs (20 µg/animal) on days 0, 14, and 28. In the immunoblot analysis, Sera from the immunized rabbits recognized the native GLPs and other proteins from larval and adult H. dromedarii ticks along with those from other tick species such as Rhipicephalus sanguineus but not Ornithodoros moubata. The effects of immunity induced by these GLPs were determined by exposing rabbits to adult H. dromedarii ticks. These results demonstrated that GLP immunization led to a slightly decreased reproductive index and significantly reduced rates of egg hatchability. These results demonstrated that immunization with the purified GLPs can provide protection against infestation by H. dromedarii and some other tick species. Further studies are needed to confirm the effectiveness of immunization with GLPs against other tick species.     

有机物-金属相互作用对重金属负载土柱中粘土矿物吸附剂再生的影响

Natural clay minerals can play an important role in crude remediation of wastewater polluted with the heavy metals (HMs) Cu,Zn and Ni.The presence and timing of addition of natural dissolved organic matter (DOM) have a significant effect on the HM removal by clay mineral sorbents.However,the influence of the presence of DOM on the remediation of the used clay mineral sorbents once saturated with HMs is largely unknown.To resolve this,clay mineral-rich soil column of varying composition,loaded (i) with Cu,Zn and Ni only,(ii) first with DOM followed by Cu,Zn and Ni,or (iii) with DOM,Cu,Zn and Ni simultaneously,was used in a set of desorption experiments.The soil columns were leached with 0.001 mol L-1 CaCl2 dissolved in water as control eluent and 0.001 mol L-1 CaCl2 dissolved in DOM as treatment eluent.During the preceding loading phase of the sorbent,the timing of DOM addition (sequential or concurrent with HMs) was found to have a significant influence on the subsequent removal of the HMs.In particular when the column was loaded with DOM and HMs simultaneously,largely irreversible co-precipitation took place.Our results indicate that the regeneration potential of clay mineral sorbents in wastewater treatment will be significantly reduced when the treated water is rich in DOM.In contrast,in manured agricultural fields (where HMs enter together with DOM),HM mobility will be lower than expected from interaction dynamics of HMs and clay minerals.     

Organoclay formulations of acetochlor: effect of high salt concentration

This study aimed to evaluate new methodology for designing ecologically acceptable formulations of acetochlor. Modification of montmorillonite with phenyltrimethylammonium chloride (PTMA) or benzyltrimethylammonium chloride (BTMA) and organoclay formulations of acetochlor were prepared in the presence of high concentrations of sodium chloride (150 g/L). Acetochlor concentration in the equilibrium solutions was determined by HPLC. Release of acetochlor in a water system was performed by a funnel experiment. Leaching of acetochlor in soil was determined by a bioassay using a column technique and Setaria viridis as a test plant. The adsorbed amounts of acetochlor on montmorillonite exchanged by PTMA or BTMA were increased as NaCl concentration increased in the equilibrium solution. Leaching of acetochlor from organoclay formulations was significantly inhibited to the top soil layer (0-5 cm) when the formulations were prepared at extreme NaCl concentration (100-150 g/L). These results are in accord with a funnel experiment that showed a reduction in acetochlor release from the montmorillonite-based formulations. The application of this method for herbicide formulation would produce ecologically acceptable herbicide formulations that can significantly minimize the risk to groundwater pollution.     

Molecular screening and risk factors of enterotoxigenic Escherichia coli and Salmonella spp. in diarrheic neonatal calves in Egypt

The aim of the present study was to carry out molecular epidemiological investigation on enterotoxigenic Escherichia coli (ETEC) K99 and Salmonella spp. in diarrheic neonatal calves. Fecal samples were obtained from 220 diarrheic calves at 9 farms related to four governorates in central and northern Egypt. E. coli and Salmonella spp. isolates were examined for E. coli K99 and Salmonella spp. using PCR. ETEC K99 was recovered from 20 (10.36 %) out of 193 isolates, whereas Salmonella spp. was recovered from nine calves (4.09%).Multivariable logistic regression was used to evaluate the risk factors associated with both infections. ETEC K99 was significantly affected by age (P < 0.01; OR: 1.812; CI 95%: 0.566–1.769), colostrum feeding practice (P < 0.01; OR: 5.525; CI 95%: 2.025–15.076), rotavirus infection (P < 0.001; OR: 2.220; CI 95%: 0.273–1.251), vaccination of pregnant dams with combined vaccine against rotavirus, coronavirus and E. coli (K99) (P < 0.001; OR: 4.753; CI 95%: 2.124–10.641), and vitamin E and selenium administration to the pregnant dam (P < 0.01; OR: 3.933; CI 95%: 0.703–1.248).Infection with Salmonella spp. was found to be significantly affected by the animal age (P < 0.05; OR: 0.376; CI 95%: 0.511–1.369), Hygiene (P < 0.05; OR: 0.628; CI 95%: 1.729–5.612), and region (P < 0. 01; OR: 0.970; CI 95%: 0.841–1.624).The results of the present study indicate the importance of PCR as rapid, effective and reliable tool for screening of ETEC and Salmonella spp. when confronted with cases of undifferentiated calf diarrhea. Moreover, identification of the risk factors associated with the spreading of bacteria causing diarrhea may be helpful for construction of suitable methods for prevention and control.     

Molecular characterization of the equine herpesvirus 1 strains RacL11 and Kentucky D

The pathogenicities of RacL11 and Kentucky D strains of equine herpesvirus 1 in the hamster infection model are different from those of Ab4p and the Japanese isolates. Virus genome restriction fragment length polymorphism analysis and sequence comparison of an intergenic region, glycoproteins and tegument genes showed higher conservation but with some strain-specific differences. These results indicate that point nucleotide differences in RacL11 and Kentucky D might be responsible for their pathogenicity in rodent models.     

Molecular diversity of Egyptian cotton (<Emphasis Type="Italic">Gossypium barbadense</Emphasis> L.) and its relation to varietal development

Twenty-eight Egyptian cotton (Gossypium barbadense L.) genotypes (varieties and hybrids) were used for analysis of genetic diversity using DNA based markers (ISSR, SSR, and EST) and to study varietal development of cotton. The ISSR markers gave the highest percentage of polymorphic bands as well as polymorphic information content compared with the other molecular markers (i.e. EST and SSR markers). Using clustering analysis, no general clustering according to the pedigree history of the genotypes was observed. Using principal coordinate analysis (PCOORDA), cotton genotypes were separated by the first three principal coordinates (PC1, PC2, and PC3) accounting for 11.5, 8.6, and 7.2% of the total genetic variance, respectively. The cotton genotypes were distributed into three parts based on the first PC, each part containing a group of varieties having a common ancestor. ‘Giza 12’ variety was the common ancestor for the varieties included in the first part and ‘Ashmouni’ variety was the common ancestor for the varieties included in the second part, while both ‘Sakha 3’ and ‘Sakha 4’ varieties were common ancestors for the varieties included in the third part. The results of the PCOORDA also showed better resolution of the genetic diversity than cluster analysis especially in the illustration of the varietal development of cotton. That means that principal coordinate analysis can be strongly used either alone or in combination with cluster analysis to discuss both genetic diversity and varietal development in the cotton genotypes.     

Molecular cloning and expression of a larval immunogenic protein from the cattle tick Boophilus annulatus

A full-length cDNA of an immunogenic protein was cloned from a cDNA library of the local Egyptian cattle tick Boophilus annulatus. Antibodies raised against B. annulatus larval proteins were used to screen a cDNA expression library. A 936bp cloned fragment was sequenced and showed an open reading frame of 516bp encoding a protein of 171 amino acids. Comparison of the deduced amino acid sequence with protein data bank revealed that the sequence is related to a sequence isolated from the hard tick Haemaphysalis qinghaiensis (Hq05). Southern blot analysis of B. annulatus genomic DNA showed that the cloned cDNA hybridized to double bands per restriction digest, suggesting that the cloned cDNA is a double copy gene. Amino acid analysis of the cloned gene revealed the presence of two casein kinase II phosphorylation sites in the N-terminal domain suggesting that this molecule may be involved in the signal transduction or gene expression pathways. RT-PCR and northern blotting revealed the presence of two isoforms of the Ba05 gene in salivary glands and in the 3-day-old eggs. The cloned gene without the signal peptide, was expressed in Escherichia coli under T7 promotor of pET-30b vector, and purified under denaturation conditions. The purified protein appeared as a single band on 12% SDS-PAGE with a molecular weight around 22.8kDa including the histidine tag of the vector. Antibodies raised against the purified molecule were used to detect the B. annulatus homologue to the Hq05 gene in whole tick, larvae and gut protein extracts. Immunoblotting revealed the presence of this molecule Ba05 only in whole tick and larval protein extracts and not in the gut protein extract. Using the same antibodies, homologues to the Ba05 gene were detected in other tick species as Hyalomma dromedarii and Rhipicephalus sp. but not in Ornithodoros moubata.     

Molecular detection of Treponema species organisms in foremilk and udder cleft skin of dairy cows with digital dermatitis

Tropical Animal Health and Production - Identification of reservoirs and transmission routes of digital dermatitis (DD)-associated Treponema spp. is considered an effective means for controlling DD...