JoVE Visualize What is visualize?
Stop Reading. Start Watching.
Advanced Search
Stop Reading. Start Watching.
Regular Search
Find video protocols related to scientific articles indexed in Pubmed.
Genotyping of Burkholderia mallei from an outbreak of glanders in Bahrain suggests multiple introduction events.
PLoS Negl Trop Dis
PUBLISHED: 09-01-2014
Show Abstract
Hide Abstract
Glanders, caused by the gram-negative bacterium Burkholderia mallei, is a highly infectious zoonotic disease of solipeds causing severe disease in animals and men. Although eradicated from many Western countries, it recently emerged in Asia, the Middle-East, Africa, and South America. Due to its rareness, little is known about outbreak dynamics of the disease and its epidemiology.
Related JoVE Video
New hepatitis E virus genotype in camels, the Middle East.
Emerging Infect. Dis.
PUBLISHED: 05-27-2014
Show Abstract
Hide Abstract
In a molecular epidemiology study of hepatitis E virus (HEV) in dromedaries in Dubai, United Arab Emirates, HEV was detected in fecal samples from 3 camels. Complete genome sequencing of 2 strains showed >20% overall nucleotide difference to known HEVs. Comparative genomic and phylogenetic analyses revealed a previously unrecognized HEV genotype.
Related JoVE Video
Specific targeting of atherosclerotic plaques in ApoE(-/-) mice using a new Camelid sdAb binding the vulnerable plaque marker LOX-1.
Mol Imaging Biol
PUBLISHED: 04-02-2014
Show Abstract
Hide Abstract
Molecular imaging has the potential to provide quantitative information about specific biological aspects of developing atherosclerotic lesions. This requires the generation of reliable, highly specific plaque tracers. This study reports a new camelid single-domain antibody fragment (sdAb) targeting the Lectin-like oxidized low-density lipoprotein receptor (LOX-1), a biomarker for the detection and molecular phenotyping of vulnerable atherosclerotic plaques.
Related JoVE Video
Novel betacoronavirus in dromedaries of the Middle East, 2013.
Emerging Infect. Dis.
PUBLISHED: 03-25-2014
Show Abstract
Hide Abstract
In 2013, a novel betacoronavirus was identified in fecal samples from dromedaries in Dubai, United Arab Emirates. Antibodies against the recombinant nucleocapsid protein of the virus, which we named dromedary camel coronavirus (DcCoV) UAE-HKU23, were detected in 52% of 59 dromedary serum samples tested. In an analysis of 3 complete DcCoV UAE-HKU23 genomes, we identified the virus as a betacoronavirus in lineage A1. The DcCoV UAE-HKU23 genome has G+C contents; a general preference for G/C in the third position of codons; a cleavage site for spike protein; and a membrane protein of similar length to that of other betacoronavirus A1 members, to which DcCoV UAE-HKU23 is phylogenetically closely related. Along with this coronavirus, viruses of at least 8 other families have been found to infect camels. Because camels have a close association with humans, continuous surveillance should be conducted to understand the potential for virus emergence in camels and for virus transmission to humans.
Related JoVE Video
Antibodies against MERS coronavirus in dromedary camels, United Arab Emirates, 2003 and 2013.
Emerging Infect. Dis.
PUBLISHED: 03-25-2014
Show Abstract
Hide Abstract
Middle East respiratory syndrome coronavirus (MERS-CoV) has caused an ongoing outbreak of severe acute respiratory tract infection in humans in the Arabian Peninsula since 2012. Dromedary camels have been implicated as possible viral reservoirs. We used serologic assays to analyze 651 dromedary camel serum samples from the United Arab Emirates; 151 of 651 samples were obtained in 2003, well before onset of the current epidemic, and 500 serum samples were obtained in 2013. Recombinant spike protein-specific immunofluorescence and virus neutralization tests enabled clear discrimination between MERS-CoV and bovine CoV infections. Most (632/651, 97.1%) camels had antibodies against MERS-CoV. This result included all 151 serum samples obtained in 2003. Most (389/651, 59.8%) serum samples had MERS-CoV-neutralizing antibody titers >1,280. Dromedary camels from the United Arab Emirates were infected at high rates with MERS-CoV or a closely related, probably conspecific, virus long before the first human MERS cases.
Related JoVE Video
Analysis of heavy and light chain sequences of conventional camelid antibodies from Camelus dromedarius and Camelus bactrianus species.
J. Immunol. Methods
PUBLISHED: 01-07-2014
Show Abstract
Hide Abstract
Camel antibodies have been widely investigated, but work has focused upon the unique heavy chain antibodies found across camelid species. These are homodimers, devoid of light chains and the first constant heavy chain domain. Camelid species also display conventional hetero-tetrameric antibodies with identical pairs of heavy and light chains; in Camelus dromedarius these constitute 25% of circulating antibodies. Few investigations have been made on this subset of antibodies and complete conventional camel IgG sequences have not been reported. Here we study the sequence diversity of functional variable and constant regions observed in 57 conventional heavy, 18 kappa and 35 lambda light chains of C. dromedarius and Camelus bactrianus. We detail sequences of the full kappa and lambda light chain, variable and CH1 region for IgG1a and IgG1b and the CH2 and CH3 region for IgG1a. The majority (60%) of IgG1 variable region sequences aligned with the human IgHV3 family (clan III) and had leader sequences beginning with MELG whereas the remaining sequences aligned with the IgHV4 (clan II) and had leader sequences beginning with MRLL. Distinct differences in CDR length were observed between the two; where CDR1 was typically 5 and 7 residues and CDR2 at 17 and 16 residues, respectively. CDR3 length of IgHV4 (range 11 to 20) was closer to that typical of VHH antibodies than that of IgHV3 (range 3 to 18 residues). Designed oligonucleotide primers have enabled identification of paired heavy and light chains of conventional camel antibodies from individual B cell clones.
Related JoVE Video
Serum amyloid A as an indicator of health status in falcons.
J. Avian Med. Surg.
PUBLISHED: 08-27-2013
Show Abstract
Hide Abstract
Serum amyloid A (SAA) is used as an indicator of health status in many species. To investigate the possible use of SAA as a health indicator in falcons, SAA levels were measured in 259 falcons of varying species and health status. A significant increase (P < .001) in SAA concentrations was observed in falcons affected by inflammatory disease compared with healthy birds and birds with noninflammatory disease. Serum amyloid A concentrations ranged from 0.1 to 6.8 mg/L (mean [SD], 3.4 +/- 1.4 mg/L) in the healthy group, from 0.8 to 8.5 mg/L (mean [SD], 4.0 +/- 3.1 mg/L) in the group with noninflammatory disease, and from 2.3 to 137.5 mg/L (mean [SD], 47.7 +/- 29.7 mg/L) in the group with inflammatory disease. In birds with chronic pododermatitis or fungal pneumonia/airsacculitis, SAA levels remained significantly increased throughout the study period. These results indicate that SAA concentrations can be used in avian medicine to assess the health status of falcons and as a prognostic indicator of certain pathologic disease processes.
Related JoVE Video
H9N2 influenza viruses from birds used in falconry.
Influenza Other Respir Viruses
PUBLISHED: 06-28-2013
Show Abstract
Hide Abstract
H9N2 avian influenza viruses continue to spread in poultry and wild birds throughout Eurasia.
Related JoVE Video
Comparing the presence of different genes in Salmonella subspecies I-IV and development of a diagnostic multiplex PCR method for identification of Salmonella subspecies.
Berl. Munch. Tierarztl. Wochenschr.
PUBLISHED: 02-02-2013
Show Abstract
Hide Abstract
Reptile-associated salmonellosis in humans has become a growing problem worldwide. Reptiles are frequently asymptomatic carriers of Salmonella and therefore, they are considered as an important reservoir for these bacteria. The classical biochemical method for Salmonella subspecies detection is time consuming, especially in samples from reptiles since they frequently carry more than one Salmonella subspecies. The aim of this study was therefore to develop a multiplex PCR assay for a rapid and accurate differentiation of Salmonella subspecies I, II, IIa, IIIb and IV. In the present study, the occurrence of the genes invA, ttrCA, iroB, STM4075, sciA, STM3690, sadA, gatD, foxA, pagN, fljB, iucD, spvB, lacZ, iutA, mdcA and irp2 was examined in 41 Salmonella strains from Middle Eastern animals (mainly reptiles) by monoplex PCR. According to the results a multiplex PCR assay was developed based on the genes ttrCA, sciA, foxA, iutA. Compared to biochemical analysis this method allowed a fast identification of the subspecies from all the Middle Eastern Salmonella strains (n = 41), as well as 79 strains from German children (n = 18) with reptile associated salmonellosis and other humans and animals (n = 61) with salmonellosis.These results revealed the multiplex PCR as a fast assay for a specific identification of Salmonella subspecies I, II, IIIa, and IIIb.
Related JoVE Video
(15)N, (13)C and (1)H resonance assignments and secondary structure determination of a variable heavy domain of a heavy chain antibody.
Biomol NMR Assign
PUBLISHED: 01-12-2013
Show Abstract
Hide Abstract
Heavy chain antibodies differ in structure to conventional antibodies lacking both the light chain and the first heavy chain constant domain (CH1). Characteristics of the antigen-binding variable heavy domain of the heavy chain antibody (VHH) including the smaller size, high solubility and stability make them an attractive alternative to more traditional antibody fragments for detailed NMR-based structural analysis. Here we report essentially complete backbone and side chain (15)N, (13)C and (1)H assignments for a free VHH. Analysis of the backbone chemical shift data obtained indicates that the VHH is comprised predominantly of ?-sheets corresponding to nearly 60 % of the protein backbone.
Related JoVE Video
Allosteric inhibition of VIM metallo-?-lactamases by a camelid nanobody.
Biochem. J.
PUBLISHED: 01-08-2013
Show Abstract
Hide Abstract
M?L (metallo-?-lactamase) enzymes are usually produced by multi-resistant Gram-negative bacterial strains and have spread worldwide. An approach on the basis of phage display was used to select single-domain antibody fragments (VHHs, also called nanobodies) that would inhibit the clinically relevant VIM (Verona integron-encoded M?L)-4 M?L. Out of more than 50 selected nanobodies, only the NbVIM_38 nanobody inhibited VIM-4. The paratope, inhibition mechanism and epitope of the NbVIM_38 nanobody were then characterized. An alanine scan of the NbVIM_38 paratope showed that its binding was driven by hydrophobic amino acids. The inhibitory concentration was in the micromolar range for all ?-lactams tested. In addition, the inhibition was found to follow a mixed hyperbolic profile with a predominantly uncompetitive component. Moreover, substrate inhibition was recorded only after nanobody binding. These kinetic data are indicative of a binding site that is distant from the active site. This finding was confirmed by epitope mapping analysis that was performed using peptides, and which identified two stretches of amino acids in the L6 loop and at the end of the ?2 helix. Because this binding site is distant from the active site and alters both the substrate binding and catalytic properties of VIM-4, this nanobody can be considered as an allosteric inhibitor.
Related JoVE Video
Comparison of diagnostic tests for the detection of Brucella spp. in camel sera.
BMC Res Notes
PUBLISHED: 12-06-2011
Show Abstract
Hide Abstract
Brucellosis in livestock causes enormous losses for economies of developing countries and poses a severe health risk to consumers of dairy products. Little information is known especially on camel brucellosis and its impact on human health. For surveillance and control of the disease, sensitive and reliable detection methods are needed. Although serological tests are the mainstay of diagnosis in camel brucellosis, these tests have been directly transposed from cattle without adequate validation. To date, little information on application of real-time PCR for detection of Brucella in camel serum is available. Therefore, this study was performed to compare the diagnostic efficiency of different serological tests and real-time PCR in order to identify the most sensitive, rapid and simple combination of tests for detecting Brucella infection in camels.
Related JoVE Video
Natural Burkholderia mallei infection in Dromedary, Bahrain.
Emerging Infect. Dis.
PUBLISHED: 07-19-2011
Show Abstract
Hide Abstract
We confirm a natural infection of dromedaries with glanders. Multilocus variable number tandem repeat analysis of a Burkholderia mallei strain isolated from a diseased dromedary in Bahrain revealed close genetic proximity to strain Dubai 7, which caused an outbreak of glanders in horses in the United Arab Emirates in 2004.
Related JoVE Video
Preclinical screening of anti-HER2 nanobodies for molecular imaging of breast cancer.
FASEB J.
PUBLISHED: 04-08-2011
Show Abstract
Hide Abstract
Accurate determination of tumor human epidermal growth factor receptor 2 (HER2)-status in breast cancer patients is possible via noninvasive imaging, provided adequate tracers are used. In this study, we describe the generation of a panel of 38 nanobodies, small HER2-binding fragments that are derived from heavy-chain-only antibodies raised in an immunized dromedary. In search of a lead compound, a subset of nanobodies was biochemically characterized in depth and preclinically tested for use as tracers for imaging of xenografted tumors. The selected compound, 2Rs15d, was found to be stable and to interact specifically with HER2 recombinant protein and HER2-expressing cells in ELISA, surface plasmon resonance, flow cytometry, and radioligand binding studies with low nanomolar affinities, and did not compete with anti-HER2 therapeutic antibodies trastuzumab and pertuzumab. Single-photon-emission computed tomography (SPECT) imaging quantification and biodistribution analyses showed that (99m)Tc-labeled 2Rs15d has a high tumor uptake in 2 HER2(+) tumor models, fast blood clearance, low accumulation in nontarget organs except kidneys, and high concomitant tumor-to-blood and tumor-to-muscle ratios at 1 h after intravenous injection. These values were dramatically lower for an irrelevant control (99m)Tc-nanobody and for (99m)Tc-2Rs15d targeting a HER2(-) tumor.
Related JoVE Video
Microarray-based genotyping of Staphylococcus aureus isolates from camels.
Vet. Microbiol.
PUBLISHED: 01-28-2011
Show Abstract
Hide Abstract
Staphylococcus aureus is a common cause of mastitis and other diseases in camels. In order to obtain data on population structure as well as on the carriage of toxin genes and resistance markers, a collection of 45 isolates from dromedaries of Dubai, United Arab Emirates, were genotyped. These isolates belonged to clonal complexes CC6 (twenty isolates; 44.44%), CC30 (sixteen isolates; 35.56%), CC188 (five isolates; 11.11%), CC152 (1 isolate, 2.2%) and to a previously un-described sequence type (ST1755: arcc-18, aroe-115, glpf-6, gmk-2 pta-109, tpi-50 and yqil-2; three isolates; 6.67%). Resistance genes proved to be rare. Only three out of 45 isolates (6.67%) carried the beta-lactamase operon. The tetracycline resistance gene tetK was also detected in three isolates (6.67%). Neither the mecA gene, defining MRSA, nor other resistance genes were found. Common virulence markers included leukocidin genes lukD+lukE (in twenty-five isolates; 55.56%), the staphylokinase gene sak (twenty-two isolates; 48.89%), the enterotoxin gene cluster egc (fifteen isolates; 33.33%), and a distinct variant of the enterotoxin A gene (sea-320E, GenBank AY196686.1; thirteen isolates; 28.89%). One CC152 isolate was positive for genes encoding the Panton-Valentine leukocidin (lukF-PV+lukS-PV). This study provides first genotyping data on the population structure and the presence of toxin genes and resistance markers of S. aureus strains in Middle Eastern camels.
Related JoVE Video
Use of a Western blot technique for the serodiagnosis of glanders.
BMC Vet. Res.
PUBLISHED: 01-19-2011
Show Abstract
Hide Abstract
The in vivo diagnosis of glanders relies on the highly sensitive complement fixation test (CFT). Frequently observed false positive results are troublesome for veterinary authorities and cause financial losses to animal owners. Consequently, there is an urgent need to develop a test with high specificity. Hence, a Western blot assay making use of a partly purified lipopolysaccaride (LPS) containing antigen of three Burkholderia mallei strains was developed. The test was validated investigating a comprehensive set of positive and negative sera obtained from horses and mules from endemic and non endemic areas.
Related JoVE Video
Coxiella burnetii abortion in captive dama gazelle (Gazella Dama) in the United Arab Emirates.
J. Zoo Wildl. Med.
PUBLISHED: 08-21-2010
Show Abstract
Hide Abstract
Abstract: Five cases of late-stage abortion in dama gazelle (Gazella dama) occurred in the United Arab Emirates. Histopathologic and molecular diagnostics found the abortions to be associated with Coxiella burnetii infection. Examination of the herd 6 mo later revealed a significant number of serologically positive animals but failed to detect the antigen in genital swabs. There are few reports in the literature of C. burnetii abortion in nondomestic ungulates and no published reports from the United Arab Emirates.
Related JoVE Video
Primordial germ cell-mediated chimera technology produces viable pure-line Houbara bustard offspring: potential for repopulating an endangered species.
PLoS ONE
PUBLISHED: 08-13-2010
Show Abstract
Hide Abstract
The Houbara bustard (Chlamydotis undulata) is a wild seasonal breeding bird populating arid sandy semi-desert habitats in North Africa and the Middle East. Its population has declined drastically during the last two decades and it is classified as vulnerable. Captive breeding programmes have, hitherto, been unsuccessful in reviving population numbers and thus radical technological solutions are essential for the long term survival of this species. The purpose of this study was to investigate the use of primordial germ cell-mediated chimera technology to produce viable Houbara bustard offspring.
Related JoVE Video
The pleural curtain of the camel (Camelus dromedarius).
Anat Rec (Hoboken)
PUBLISHED: 04-22-2010
Show Abstract
Hide Abstract
The visceral pleura of the camel (Camelus dromedarius) possesses a fibrous curtain of pleural threads or extensions along its basal margins, which extends into the pleural cavity of the costophrenic recesses. These threads are lined by mesothelium and have a core or stroma, which is largely collagenous. Small threads are avascular and nearly acellular. In larger proximal threads, blood vessels in the stroma are often arranged in a branching network, with irregular endothelia surrounded by several incomplete basal laminae. Lymphocytes and other inflammatory cell types aggregate in the stroma near blood vessels. The threads are lined by typical mesothelium except in patches close to the main pleural surface. These patches consist of layers of loosely applied cells with numerous cellular processes and features suggestive of phagocytosis. The position of the pleural curtain in the costophrenic recess and the presence of possibly phagocytotic cells suggest that the pleural curtain stirs, samples, and cleans the pleural fluid. The pleural curtain appears to be a feature of camelids and has also been seen in giraffes.
Related JoVE Video
Comparison of commercial DNA preparation kits for the detection of Brucellae in tissue using quantitative real-time PCR.
BMC Infect. Dis.
PUBLISHED: 04-20-2010
Show Abstract
Hide Abstract
The detection of Brucellae in tissue specimens using PCR assays is difficult because the amount of bacteria is usually low. Therefore, optimised DNA extraction methods are critical. The aim of this study was to assess the performance of commercial kits for the extraction of Brucella DNA.
Related JoVE Video
Analysis of camelid IgG for antivenom development: Immunoreactivity and preclinical neutralisation of venom-induced pathology by IgG subclasses, and the effect of heat treatment.
Toxicon
PUBLISHED: 04-07-2010
Show Abstract
Hide Abstract
Antivenom is the most effective treatment of snake envenoming and is manufactured from the IgG of venom-immunised horses and sheep. Camelids have a unique IgG structure which may account for the report that camel IgG is less immunogenic and less likely to activate complement than equine or ovine IgG. Camelid IgG therefore offers potential safety advantages over conventional IgGs used for antivenom manufacture. The reported thermostability of camelid IgG also holds promise in the inclusion of a relatively inexpensive anti-microbial heat step in antivenom manufacture. However, these potential benefits of camelid IgG would be much reduced if any one of the three camel IgG subclasses dominated, or under-performed, the serological response of camels to venom immunisation because of the prohibitive manufacturing costs of having to purify, or exclude, one or more IgG subclasses. This study compared the titre, antigen-specificity, relative avidity and ability to neutralise the haemorrhagic and coagulopathic effects of Echis ocellatus venom of each IgG subclass from the venom-immunised camels. The results demonstrated that no one IgG subclass consistently out-performed or under-performed the others in their immunoreactivity to venom proteins and ability to neutralise venom-induced pathologies. We concluded therefore that IgG taken from a pool of immunised camels could be processed into antivenom without requiring the implementation of expensive chromatographic separations to select, or indeed to exclude, a specific IgG subclass. The immunoreactivity of the heavy and light chain, IgG1 subclass, was markedly more vulnerable to extreme heat treatment than the heavy chain-only IgG2 and IgG3 subclasses.
Related JoVE Video
In vitro antiviral activity of single domain antibody fragments against poliovirus.
Antiviral Res.
PUBLISHED: 03-18-2010
Show Abstract
Hide Abstract
VHHs or Nanobodies are single-domain antigen-binding fragments derived from heavy chain antibodies found in camelids. It has already been shown that complex protein mixtures and even whole organisms elicit good immune responses in camelids; therefore we hypothesized that VHHs selected from a dromedary immunized with poliovirus type 1 might inhibit the in vitro replication of poliovirus through binding to essential biological sites on the viral capsid. In this study, we aimed to determine whether VHHs inhibit wild-type and vaccine strains of poliovirus type 1. Interestingly, VHHs showed a potent antipolio activity with EC50 values in the low nanomolar range. Moreover, these antibody fragments completely blocked viral multiplication at higher concentrations. Remarkably, no (immune) escape variants against some of these VHHs could be generated. In conclusion, VHHs fulfil several in vitro requirements to be assigned as potential antiviral compounds for further development of an anti-poliovirus drugs.
Related JoVE Video
Analysis of camelid antibodies for antivenom development: Neutralisation of venom-induced pathology.
Toxicon
PUBLISHED: 02-05-2010
Show Abstract
Hide Abstract
Camelid IgG has been reported to be less immunogenic, less able to activate the complement cascade and more thermostable than IgG from other mammals, and has the ability to bind antigens that are unreactive with other mammalian IgGs. We are investigating whether these attributes of camelid IgG translate into antivenom with immunological and venom-neutralising efficacy advantages over conventional equine and ovine antivenoms. The objective of this study was to determine the preclinical venom-neutralising effectiveness of IgG from camels immunised with venoms, individually or in combination, of the saw-scaled viper, Echis ocellatus, the puff adder, Bitis arietans and the spitting cobra, Naja nigricollis - the most medically-important snake species in West Africa. Neutralisation of the pathological effects of venoms from E. ocellatus, B. arietans and N. nigricollis by IgG from the venom-immunised camels, or commercial antivenom, was compared using assays of venom lethality (ED(50)), haemorrhage (MHD) and coagulopathy (MCD). The E. ocellatus venom ED(50), MHD and MCD results of the E. ocellatus monospecific camel IgG antivenom were broadly equivalent to comparable ovine (EchiTAbG, MicroPharm Ltd, Wales) and equine (SAIMR Echis, South African Vaccine Producer, South Africa) antivenoms, although the equine antivenom required half the amount of IgG. The B. arietans monospecific camel IgG neutralised the lethal effects of B. arietans venom at one fourth the concentration of the SAIMR polyspecific antivenom (a monospecific B. arietans antivenom is not available). The N. nigricollis camel IgG antivenom was ineffective (at the maximum permitted dose, 100 mul) against the lethal effects of N. nigricollis venom. All the equine polyspecific antivenoms required more than 100 microl to be effective against this venom. The polyspecific camel IgG antivenom, prepared from five camels, was effective against the venom-induced effects of E. ocellatus but not against that of B. arietans and N. nigricollis venoms. No direct correlation was evident between either camel IgG relative avidity or titre and the effectiveness of venom neutralisation in preclinical assays.
Related JoVE Video
Analysis of camelid IgG for antivenom development: Serological responses of venom-immunised camels to prepare either monospecific or polyspecific antivenoms for West Africa.
Toxicon
PUBLISHED: 02-05-2010
Show Abstract
Hide Abstract
Snake envenoming is a significant cause of mortality and morbidity in sub-Saharan Africa. The only effective treatment, antivenom, has been in short supply since the 1990s. Whilst the humanitarian response by some antivenom producers has significantly improved the situation, strategies to ensure the long term stability of antivenom supply are still necessary. We are investigating whether the potential safety and logistic advantages of camel IgG antivenom can be exploited to improve antivenom provision in many countries where snakebite is endemic. This study assessed the IgG titre, specificity and avidity of camels immunised with either individual venom or a mixture of venoms from the three most medically important snakes of West Africa, the saw-scale viper (Echis ocellatus), the puff adder (Bitis arietans) and the spitting cobra (Naja nigricollis). Seven of the eight immunised camels generated IgG titres and avidities comparable to, or exceeding, that of commercial equine and ovine antivenoms that are highly effective in envenomed patients. In this, the first of a series of reports on the potential utility of camelid IgG antivenom, we describe an immunisation protocol that induced potent, sustained serological response of very high antibody avidity. These attributes suggest, from an immunological perspective, that camel IgG antivenoms should be as efficacious as current equine and ovine antivenoms.
Related JoVE Video
Isolation of highly pathogenic avian influenza H5N1 virus from Saker falcons (Falco cherrug) in the Middle East.
Adv Virol
PUBLISHED: 12-16-2009
Show Abstract
Hide Abstract
There is accumulating evidence that birds of prey are susceptible to fatal infection with highly pathogenic avian influenza (HPAI) virus. We studied the antigenic, molecular, phylogenetic, and pathogenic properties of 2 HPAI H5N1 viruses isolated from dead falcons in Saudi Arabia and Kuwait in 2005 and 2007, respectively. Phylogenetic and antigenic analyses grouped both isolates in clade 2.2 (Qinghai-like viruses). However, the viruses appeared to have spread westward via different flyways. It remains unknown how these viruses spread so rapidly from Qinghai after the 2005 outbreak and how they were introduced into falcons in these two countries. The H5N1 outbreaks in the Middle East are believed by some to be mediated by wild migratory birds. However, sporting falcons may be at additional risk from the illegal import of live quail to feed them.
Related JoVE Video
A comparative study of serological tests and PCR for the diagnosis of equine piroplasmosis.
Parasitol. Res.
PUBLISHED: 09-10-2009
Show Abstract
Hide Abstract
A total of 105 serum samples from endurance horses from different stables in Dubai were examined for the presence of antibodies against Theileria equi and Babesia caballi using immunofluorescence antibody test (IFAT) and competitive enzyme-linked immunosorbent assay (cELISA). A TaqMan real-time polymerase chain reaction (PCR) was used to detect DNA of piroplasms in specimens of clotted blood or EDTA blood samples of the same animals. Out of the 105 serum samples, the IFAT detected antibodies against T. equi in 35 (33.3%) cases while the cELISA gave 34 (32.4%) positive results. Eleven (10.5%) of the 105 sera were positive in the B. caballi IFAT while an additional five (4.8%) other specimens were diagnosed positive using the cELISA. The serological results showed that 13 (12.4%) horses had antibodies against both T. equi and B. caballi. The TaqMan real-time PCR detected DNA of piroplams in 33 (31.4%) samples while serological methods found antibodies in 38 (36.2%) horses.
Related JoVE Video
Increasing fatal AA amyloidosis in hunting falcons and how to identify the risk: a report from the United Arab Emirates.
Amyloid
PUBLISHED: 08-07-2009
Show Abstract
Hide Abstract
In hunting falcons, a fatal syndrome of wasting, weight loss, green mutes and, finally, sudden death of emaciated birds has been observed in the United Arab Emirates (UAE). Histological examination using Congo red has revealed amyloid in most organs, in particular in the liver, spleen, kidney, and adrenal glands. Moreover, a retrospective study revealed amyloidosis in 100 cases among a total of 623 necropsied falcons between August 1995 and March 2004 in Dubai/UAE (16%; varying from 8 to 30% in different raptor bird species). The amyloid was immunohistochemically classified as amyloid A (AA), which was confirmed by Western blot analysis and N-terminal amino acid sequence analysis, suggesting it to be secondary to a chronic inflammatory process. Retrospective analysis has indicated a significantly increased prevalence of bumble foot and visceral gout among falcons with amyloidosis. In addition, a significant increase of amyloidosis from 5.6% of necropsied falcons with amyloidosis in 1995 to 40.0% in 2004 has been noticed. Finally, a semi-quantitative serum test for falcon serum amyloid A (f-SAA) has been developed. Among 38 falcons with fatal AA amyloidosis, f-SAA was increased pathologically in 36, whereas f-SAA was elevated in only one of 15 apparently disease-free falcons (p < 0.001). This significant result indicates that a normal f-SAA will indicate a minimal or even absent risk of succumbing to AA amyloidosis.
Related JoVE Video
Prevalence-dependent use of serological tests for diagnosing glanders in horses.
BMC Vet. Res.
PUBLISHED: 02-16-2009
Show Abstract
Hide Abstract
The internationally mandatory complement fixation test (CFT) for testing of equine sera for the absence of glanders has repeatedly led to discrepant results. Not only do "false positive" sera pose a problem for the diagnostician and the animal health authorities but they can also result in significant financial losses for the animal owners.Due to the very low prevalence of glanders in the horse population it is of major importance to use tests with a high specificity to overcome unreliable predictive values. We have compared formalin-fixed B. mallei whole cell antigen and a well characterised mouse monoclonal antibody with regard to their specificity and sensitivity for glanders serodiagnosis using CFT, an indirect (i) and a competitive (c) ELISA platform.
Related JoVE Video
Surface display of a single-domain antibody library on Gram-positive bacteria.
Cell. Mol. Life Sci.
Show Abstract
Hide Abstract
Combinatorial protein engineering for selection of proteins with novel functions, such as enzymes and affinity reagents, is an important tool in biotechnology, drug discovery, and other biochemical fields. Bacterial display is an emerging technology for isolation of new affinity proteins from such combinatorial libraries. Cells have certain properties that are attractive for directed evolution purposes, in particular the option to use quantitative flow-cytometric cell sorting for selection of binders. Here, an immune library of around 10(7) camelid single-domain antibody fragments (Nanobodies) was displayed on both the Gram-positive bacterium Staphylococcus carnosus and on phage. As demonstrated for the first time, the antibody repertoire was found to be well expressed on the bacterial surface and flow-cytometric sorting yielded a number of Nanobodies with subnanomolar affinity for the target protein, green fluorescent protein (GFP). Interestingly, the staphylococcal output repertoire and the binders from the phage display selection contained two slightly different sets of clones, containing both unique as well as several similar variants. All of the Nanobodies from the staphylococcal selection were also shown to enhance the fluorescence of GFP upon binding, potentially due to the fluorescence-based sorting principle. Our study highlights the impact of the chosen display technology on the variety of selected binders and thus the value of having alternative methods available, and demonstrates in addition that the staphylococcal system is suitable for generation of high-affinity antibody fragments.
Related JoVE Video
Generation of single domain antibody fragments derived from camelids and generation of manifold constructs.
Methods Mol. Biol.
Show Abstract
Hide Abstract
Immunizing a camelid (camels and llamas) with soluble, properly folded proteins raises an affinity-matured immune response in the unique camelid heavy-chain only antibodies (HCAbs). The peripheral blood lymphocytes of the immunized animal are used to clone the antigen-binding antibody fragment from the HCAbs in a phage display vector. A representative aliquot of the library of these antigen-binding fragments is used to retrieve single domain antigen-specific binders by successive rounds of panning. These single domain antibody fragments are cloned in tandem to generate manifold constructs (bivalent, biparatopic or bispecific constructs) to increase their functional affinity, to increase specificity, or to connect two independent antigen molecules.
Related JoVE Video
Prevalence, serovars, phage types, and antibiotic susceptibilities of Salmonella strains isolated from animals in the United Arab Emirates from 1996 to 2009.
Trop Anim Health Prod
Show Abstract
Hide Abstract
The aim of this study was to give some insights into the prevalence, serovars, phage types, and antibiotic resistances of Salmonella from animal origin in the United Arab Emirates. Data on diagnostic samples from animals (n = 20,871) examined for Salmonella between 1996 and 2009 were extracted from the databases of the Central Veterinary Research Laboratory in Dubai and from typed strains (n = 1052) from the Robert Koch Institute, Wernigerode Branch in Germany and analyzed for general and animal-specific trends. Salmonella was isolated from 1,928 (9 %) of the 20,871 samples examined. Among the 1,052 typed strains, most were from camels (n = 232), falcons (n = 166), bustards (n = 101), antelopes (n = 66), and horses (n = 63). The predominant serovars were Salmonella Typhimurium (25 %), Salmonella Kentucky (8 %), followed by Salmonella Frintrop (7 %), and Salmonella Hindmarsh (5 %). When analyzed by animal species, the most frequent serovars in camels were Salmonella Frintrop (28 %) and Salmonella Hindmarsh (21 %), in falcons Salmonella Typhimurium (32 %), in bustards Salmonella Kentucky (19 %), in antelopes Salmonella Typhimurium (9 %), and in horses Salmonella Typhimurium (17 %) and S. Kentucky (16 %). Resistance of all typed Salmonella strains (n = 1052) was most often seen to tetracycline (23 %), streptomycin (22 %), nalidixic acid (18 %), and ampicillin (15 %). These data show trends in the epidemiology of Salmonella in different animal species which can be used as a base for future prevention, control, and therapy strategies.
Related JoVE Video
Nanobodies targeting mouse/human VCAM1 for the nuclear imaging of atherosclerotic lesions.
Circ. Res.
Show Abstract
Hide Abstract
A noninvasive tool allowing the detection of vulnerable atherosclerotic plaques is highly needed. By combining nanomolar affinities and fast blood clearance, nanobodies represent potential radiotracers for cardiovascular molecular imaging. Vascular cell adhesion molecule-1 (VCAM1) constitutes a relevant target for molecular imaging of atherosclerotic lesions.
Related JoVE Video
A serologic survey for Coxiella burnetii in semi-wild ungulates in the Emirate of Dubai, United Arab Emirates.
J. Wildl. Dis.
Show Abstract
Hide Abstract
Q fever, a highly infectious zoonotic disease caused by Coxiella burnetii, has not been officially reported in the United Arab Emirates (UAE). This first serosurvey of a large group of semi-free-ranging animals in the UAE indicates that a wide range of ungulates have been exposed C. burnettii in the region.
Related JoVE Video

What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.