Development of cell culture based peste des petits ruminants (PPR) virus vaccine candidate from Bangladeshi isolates

This study was conducted to develop a cell culture based PPR virus vaccine candidate using recent Bangladeshi strain of peste des petits ruminant's (PPR) virus. PPR virus was isolated from field outbreaks, confirmed by RT-PCR and used as viral inoculum for serial passaging in Vero cells for adaptation and attenuation. 60th serial passage had completed and RT-PCR and real time RT-PCR were done in every 5 passages for confirmation of PPR virus in tissue culture fluid (TCF). To assess the adaptation and attenuation cytopathology, virus titration, sequencing of both F and N genes and live animal experimentation were done. Different cellular alterations produced by PPR virus in infected Vero cells including syncytia formation, development of both intranuclear and intra cytoplasmic inclusion bodies and finally cell degradation are the indications of adaptation. The virus titre was found 2.5, 3.31, 3.55, 4.44, 4.71 and 6.5 Log₁₀ TCID₅₀/ml at 10th, 20th, 30th, 40th, 50th and 60th passages level respectively. In F gene sequence analysis it has been observed that few nucleotide (nt) and mino acid (aa) has been substituted as the effects of serial passaging of PPR virus in Vero cells. TCF at 60th passage level was found effective to produced protective antibody (Ab) titre in live animal experimentation. It is concluded that serially passaged and Vero cells adapted PPR virus TCF could be used as a vaccine candidate for further use to develop a potent & effective vaccine against PPR diseases.

Avian influenza and Newcastle disease virusindead chickens in markets in Dhaka, Bangladesh in 2011-2012

A virological survey for avian influenza (AI) and Newcastle disease (ND) was conducted in two selected live bird markets (LBMs), namely Kaptan Bazar and Karwan Bazar in Dhaka city, Bangladesh from August 2011 to July 2012. A total of 513 dead chickens were collected. An immune-chromatographic rapid antigen test for Type A influenza virus and both conventional and real time RT-PCR were used for the detection and characterization of AI and ND viruses. All carcasses were first screened by the rapid antigen test kit and 93 were positive for Type A influenza virus. RT-PCR on a representative number of rapid antigen test positive samples (n = 24) confirmed the presence of Type A influenza virus and mostly H5 influenza virus (22 out of 24 tested samples). Influenza rapid test negative samples (n = 420) were subjected to routine necropsy. Heat stress, suffocation and physical injury were the most common cause of mortality (163 cases), followed by ND, suspected to be the cause of 85 deaths. On molecular investigation of these 85 samples, the presence of ND virus was confirmed in 59 and AI virus in 6; 15 were negative for both ND and AI viruses and 5 were unsuitable for investigation. Among the 59 ND confirmed cases 18 also contained AI virus. In summary, out of 513 carcasses 117 (22.81%) contained AI virus and 59 (11.50%) contained ND virus. Eighteen (3.51%) carcasses contained both AI and ND viruses. The findings suggest that both AI and ND should be considered as major threats to the poultry industry.Bangl. vet. 2016. Vol. 33, No. 1, 8-15

Molecular evolution of H5N1 highly pathogenic avian influenza viruses in Bangladesh between 2007 and 2012

In Bangladesh, highly pathogenic avian influenza (HPAI) virus subtype H5N1 was first detected in February 2007. Since then the virus has become entrenched in poultry farms of Bangladesh. There have so far been seven human cases of H5N1 HPAI infection in Bangladesh with one death. The objective of the present study was to investigate the molecular evolution of H5N1 HPAI viruses during 2007 to 2012. Partial or complete nucleotide sequences of all eight gene segments of two chicken isolates, five gene segments of a duck isolate and the haemagglutinin gene segment of 18 isolates from Bangladesh were established in the present study and subjected to molecular analysis. In addition, full-length sequences of different gene segments of other Bangladeshi H5N1 isolates available in GenBank were included in the analysis. The analysis revealed that the first introduction of clade 2.2 virus in Bangladesh in 2007 was followed by the introduction of clade 2.3.2.1 and 2.3.4 viruses in 2011. However, only clade 2.3.2.1 viruses could be isolated in 2012, indicating progressive replacement of clade 2.2 and 2.3.4 viruses. There has been an event of segment re-assortment between H5N1 and H9N2 viruses in Bangladesh, where H5N1 virus acquired the PB1 gene from a H9N2 virus. Point mutations have accumulated in Bangladeshi isolates over the last 5 years with potential modification of receptor binding site and antigenic sites. Extensive and continuous molecular epidemiological studies are necessary to monitor the evolution of circulating avian influenza viruses in Bangladesh.

Further evidence for the association of distinct amino acid residues with in vitro and in vivo growth of infectious bursal disease virus

A cell-culture-adapted reverse genetics strain of very virulent infectious bursal disease virus (IBDV) of chickens, designated as BD-3tcC, having four amino acid substitutions (Gln253His, Asp279Asn, Ala284Thr and Ser330Arg) in the capsid protein VP2 was tested for its genetic stability during serial passage in chickens and chicken embryo fibroblast (CEF) cell culture. Results of in vitro and in vivo experiments demonstrated that all four introduced mutations in BD-3tcC remained stable during serial passage in CEF cell culture, but during passage in chickens, amino acid residues at position 253 and 284 reverted from histidine to glutamine and threonine to alanine, respectively. In a parallel experiment, the same substitutions also occurred in a conventionally attenuated vaccine strain D-78 on serial passage in chickens. However, no reversion or substitution took place at positions 279 and 330 during in vivo passage of the mutant virus BD-3tcC or vaccine virus D-78. The findings provide conclusive evidence that while IBDV requires histidine and threonine at positions 253 and 284 for cell culture adaptation, glutamine and alanine at these positions are selected preferentially during in vivo replication.

Isolation and identification of Newcastle disease viruses from field outbreaks in chickens and pigeons

Eleven dead or sick birds submitted from farms in the year 2010 with a history of sudden death with respiratory and/or diarrhoeal signs were used for isolation and identification of Newcastle disease virus (NDV). All samples were subjected to routine necropsy. Pooled respiratory tissues were inoculated in embryonated chicken eggs and chicken embryo fibroblast (CEF) cell culture. The growth of NDV was confirmed by embryo mortality, cytopathic effects (CPE) in cell culture, haemagglutination (HA) and haemagglutination inhibition (HI) test. The presence of NDV was confirmed by reverse transcriptionpolymerase chain reaction (RT-PCR). At necropsy seven cases were tentatively diagnosed as Newcastle disease (ND). Out of seven ND-suspected samples, four yielded virus in both embryos and cell culture, while one was positive only in embryos, one only in cell culture and one sample was negative in both embryos and cell culture. RT-PCR successfully amplified a 766 bp fragment covering parts of Matrix and Fusion protein genes of NDV from the samples that were positive either in embryos or in cell culture. It is suggested that RT-PCR could be a rapid and sensitive tool for the detection of NDV. DOI: http://dx.doi.org/10.3329/bvet.v29i2.14341 Bangl. vet. 2012. Vol. 29, No. 2, 41-48

Comparison of genes as target for molecular diagnosis of peste des petits ruminants in goats

Peste des petits ruminants (PPR) are an acute viral disease of sheep and goats. Rapid and accurate diagnosis is essential for successful control. Reverse transcriptase polymerase chain reaction (RT-PCR), a molecular diagnostic test based on amplification of the gene target is more sensitive than other tests. The study was to find an efficient primer set and structural gene, which would be more specific and sensitive for detecting PPR virus (PPRV) in field samples. Six primer sets for six structural genes of PPR were used. Primer against NP gene (np3/np4) was specific and sensitive. To ensure efficient amplification and detection of viruses in field samples, more than one set of primers should be used and F and N gene specific primers were the most suitable. DOI: http://dx.doi.org/10.3329/bvet.v29i2.14343 Bangl. vet. 2012. Vol. 29, No. 2, 56-62

Development of multiplex reverse transcription polymerase chain reaction (RT-PCR) for simultaneous detection of matrix, haemagglutinin and neuraminidase genes of H5N1 avian influenza virus

Influenza A virus, subtype H5N1 causes a fatal disease in domestic poultry and could spread directly from poultry to humans. The aim of this study was to develop a multiplex reverse transcription polymerase chain reaction (mRT-PCR) for simultaneous detection of Type A influenza virus-specific matrix protein (M) gene as well as H5 and N1 genes of highly pathogenic avian influenza (HPAI) viruses. Finnzymes Phusion-Flash High- Fidelity PCR Master Mix (Finnzymes Oy, Finland) and Qiagen one-step RT-PCR enzyme mix (Qiagen, Germany) were used in a one-step RT-PCR. RNA was extracted from two known positive samples using Qiagen RNA extraction kit. RT-PCR was carried out with a mixture of primers specific for the Type A influenza virus matrix protein (M), and H5 and N1 genes of H5N1 HPAI viruses in a single reaction system. The mRT-PCR cDNA products were visualized by gel electrophoresis. The mRT-PCR yielded fragments of 245 bp for M, 545 bp for H5 and 343 bp for N1 genes of HPAI virus, which were clearly distinguishable. The mRT-PCR using the Finnzymes Phusion-Flash High-Fidelity PCR Master Mix (Finnzymes Oy, Finland) with Qiagen one-step RT-PCR Enzyme Mix (Qiagen, Germany) required only one hour and 20 minutes. (Bangl. vet. 2011. Vol. 28, No. 2, 55 – 59)DOI: http://dx.doi.org/10.3329/bvet.v28i2.10653

Synergistic effect of PKC activation and actin filament disruption on carbonate apatite-facilitated lymphocyte transfection

Leukemia and lymphoma cells are potential targets for genetic manipulation in cancer therapy. On the other hand, genetically modified autologous lymphocytes expressing a chimeric antigen against a receptor overexpressed in tumor cells or tumor vasculature are promising cell-based therapeutics for cancer.However, the lack of a smart device for efficient transgene delivery to the lymphocytes poses the major obstacle to the successful clinical applications of these attractive approaches. Recently, we developed a carbonate apatite-based nanocarrier system for effective intracellular delivery and release of DNA molecules, achieving very high level of transgene expression in both primary and cancer cells. Although its efficacy in human T leukemia cells is relatively poor, immobilization of fibronectin and/or chimeric E-cadherin-Fc on particle surface could enhance transgene delivery in presence of an actin filament disrupter. Here, we report for the first time that simultaneous stimulation of human T leukemia cells by a protein kinase C (PKC) activator, a Ca(2+) ionophore and an actin filament disrupter dramatically accelerated carbonate apatite-mediated transgene delivery in the cells, resulting in over 100-fold more efficacy than commcercially available lipofectamine.

New introduction of clade 2.3.2.1 avian influenza virus (H5N1) into Bangladesh

Since the first outbreak of highly pathogenic H5N1 avian inafluenza (HPAI) in Bangladesh in February 2007, a total of 519 disease events have been reported till 22 October 2011. Partial HA gene sequences of 11 selected H5N1 HPAI isolates of 2007 to 2011 were determined and subjected to phylogenetic analysis. The study revealed a recent introduction of clade 2.3.2 and 2.3.4 viruses into Bangladesh in 2011 in addition to clade 2.2 viruses that had been in circulation since 2007. Clade 2.3.2 virus isolates from Bangladesh are phylogenetically related to the newly designated clade 2.3.2.1 viruses, reported recently from Asia and Eastern Europe.

Fluoride enhances transfection activity of carbonate apatite by increasing cytoplasmic stability of plasmid DNA

Intracellular delivery of a functional gene or a nucleic acid sequence to specifically knockdown a harmful gene is a potential approach to precisely treat a critical human disease. The intensive efforts in the last few decades led to the development of a number of viral and non-viral synthetic vectors. However, an ideal delivery tool in terms of the safety and efficacy has yet to be established. Recently, we have developed pH-sensing inorganic nanocrystals of carbonate apatite for efficient and cell-targeted delivery of gene and gene-silencing RNA. Here we show that addition of very low level of fluoride to the particle-forming medium facilitates a robust increase in transgene expression following post-incubation of the particles with HeLa cells. Confocal microscopic observation and Southern blotting prove the cytoplasmic existence of plasmid DNA delivered by likely formed fluoridated carbonate apatite particles while degradation of plasmid DNA presumably by cytoplasmic nucleases was noticed following delivery with apatite particles alone. The beneficial role of fluoride in enhancing carbonate apatite-mediated gene expression might be due to the buffering potential of generated fluoridated apatite in endosomal acidic environment, thereby increasing the half-life of delivered plasmid DNA.

Disrupting actin filaments promotes efficient transfection of a leukemia cell line using cell adhesive protein-embedded carbonate apatite particles

Tumor cells such as leukemia and lymphoma cells are obvious and attractive targets for gene therapy. Gene transfer and expression for cytokine and immunomodulatory molecules in various kinds of tumor cells have been shown to mediate tumor regression and antimetastatic effects. Moreover, genetically modified leukemia cells expressing costimulatory molecules or cytokines are likely to have significant therapeutic roles for patients with leukemia. One of the major hurdles to the successful implementation of these promising approaches is the lack of a suitable nanocarrier for transgene delivery and expression in a safe and effective manner. Recently, we reported on the development of a safe, efficient nanocarrier system of carbonate apatite that can assist both intracellular delivery and release of DNA, leading to very high level of transgene expression in cancer and primary cells. However, its efficiency in human lymphocytes is poor. We show here that nanocrystals of carbonate apatite, when electrostatically associated with fibronectin and/or E-cadherin-Fc, accelerated transgene delivery in a human T leukemia cell line (Jurkat). Moreover, transgene expression efficiency could be enhanced dramatically with the cell adhesive protein-embedded particles finally up to 150 times by selectively disrupting the actin filaments.

High performance DNA nano-carriers of carbonate apatite: multiple factors in regulation of particle synthesis and transfection efficiency

Increasing attention is being paid on synthetic DNA delivery systems considering some potential life-threatening effects of viral particles, for development of gene-based nano-medicine in the 21st century. In the current nonviral approaches, most of the efforts have been engaged with organic macromolecules like lipids, polymers, and peptides, but comparatively fewer attempts were made to evaluate the potential of inorganic materials for gene delivery. We recently reported that biodegradable nanoparticles of carbonate apatite are highly efficient in transfecting a wide variety of mammalian cells. Here we show that a number of parameters actively regulate synthesis of the nanoparticles and their subsequent transfection efficacy. Development of “supersaturation”, which is the prerequisite for generation of such particles, could be easily modulated by reactant concentrations, pH of the buffered solution, and incubation temperatures, enabling us to establish a flexible particle generation process for highly productive trans-gene delivery. Carbonate incorporation into the particles have been proposed for generating nano-size particles resulting in cellular uptake of huge amount of plasmid DNA as well as endosome destabilization facilitating significant release of DNA from the endosomes.

pH-sensitive nano-crystals of carbonate apatite for smart and cell-specific transgene delivery

The treatment of a human disease at a genetic level by either providing a cell with a functional gene or a nucleic acid sequence to precisely silence a harmful gene, is a powerful approach that could revolutionise clinical medicine. Despite the existence of both genetically engineered viral vectors and synthetically designed lipid- or polymer-based nanocarriers, an ideal delivery system in terms of safety and efficacy is still lacking. This editorial reports on the development of biocompatible, inorganic nanoparticles of carbonate apatite, which has the unique features essentially required for smart delivery, as well as for the expression of a genetic material in a mammalian cell.

Effective delivery with enhanced translational activity synergistically accelerates mRNA-based transfection

mRNA instead of DNA provides a new and attractive approach for gene therapy and genetic vaccination. Current technologies for mRNA delivery are based on cationic lipids with DOTAP being the most efficient one. We previously reported on the synthesis of an inorganic-organic hybrid carrier by embedding inorganic nano-particles of carbonate apatite onto liposomal carrier DOTAP and demonstrated its high transfection potency of luciferase mRNA both in mitotic and non-mitotic cells. Here we show that in addition to the carrier design for effective endocytosis and release of mRNA to the cytoplasm, enhancement of mRNA translation efficiency is a prerequisite for maximum protein expression. We used the modified cap analog (ARCA) during in vitro transcription of luciferase DNA for proper cap orientation and demonstrated that transfection with ARCA-mRNA resulted in higher protein expression than the mRNA with usual cap structure for both DOTAP and DOTAP-apatite complex. Secondly, exogenous poly(A) was co-delivered with mRNA by the DOTAP-apatite, resulting in very significant expression compared to mRNA delivery only. Finally, when combined both of the effects of smart carrier and the modifications at mRNA translational level, a notable enhancement (100 times) was achieved as compared to the existing DOTAP-based liposome technology. Our findings, therefore, unveiled a novel approach that an effective delivery system can be developed by the improvement of the gene expression level in combination with the enhancement of the carrier potency.

Surface functionalization of inorganic nano-crystals with fibronectin and E-cadherin chimera synergistically accelerates trans-gene delivery into embryonic stem cells

Stem cells holding great promises in regenerative medicine have the potential to be differentiated to a specific cell type through genetic manipulation. However, conventional ways of gene transfer to such progenitor cells suffer from a number of disadvantages particularly involving safety and efficacy issues. Here, we report on the development of a bio-functionalized inorganic nano-carrier of DNA by embedding fibronectin and E-cadherin chimera on the carrier, leading to its high affinity interactions with embryonic stem cell surface and accelerated trans-gene delivery for subsequent expression. While only apatite nano-particles were very inefficient in transfecting embryonic stem cells, fibronectin-anchored particles and to a more significant extent, fibronectin and E-cadherin-Fc-associated particles dramatically enhanced trans-gene delivery with a value notably higher than that of commercially available lipofection system. The involvement of both cell surface integrin and E-cadherin in mediating intracellular localization of the hybrid carrier was verified by blocking integrin binding site with excess free fibronectin and up-regulating both integrin and E-cadherin through PKC activation. Thus, the new establishment of a bio-functional hybrid gene-carrier would promote and facilitate development of stem cell-based therapy in regenerative medicine.

pH-sensing nano-crystals of carbonate apatite: effects on intracellular delivery and release of DNA for efficient expression into mammalian cells

Two unique and fascinating properties of carbonate apatite which are well-known in hard tissue engineering, have been unveiled, for the first time, for the development of the simplest, but most efficient non-viral gene delivery device - ability of preventing the growth of crystals needed for high frequency DNA transfer across a plasma membrane and a fast dissolution rate for effective release of DNA during endosomal acidification, leading to a remarkably high transgene expression (5 to 100-fold) in mammalian cells compared to the widely used transfecting agents. Moreover, by modulating the crystal dissolution rate of carbonate apatite through incorporation of fluoride or strontium into it, transfection activity could be dramatically controlled, thus shedding light on a new barrier in the non-viral route, which was overlooked so far. Thus we have developed an innovative technology with significant insights, that would come as a promising tool for both basic research laboratories and clinical settings.

Rapid isolation of high quality, multimeric plasmid DNA using zwitterionic detergent

Purification of plasmid DNA from bacteria is an essential tool in recombinant DNA technology and has become an essential task in laboratories to industries. Moreover, the recent progress of "Gene therapy" and "Genetic vaccination" also demands production of pharmaceutical grade plasmid DNA in 'kilogram' level. Despite existence of a number of purification protocols, all most all have been originated from a pioneering work [Birnboim, H.C., Doly, J., 1979. A rapid extraction procedure for screening recombinant plasmid DNA. Nucleic Acids Res. 7, 1513-1523] and so suffer from one or more drawbacks, such as purification time, purity or quantity of isolated plasmid DNA. Here, we have reported an innovative approach for isolation of highly pure and functional plasmid DNA in significant amount, based on generation of "soft protein aggregate" with the help of zwitterionic detergents and alkali. Solibilized proteins and RNA could be removed by a simple and mild washing with Tris buffer of low ionic strength and multimeric plasmid DNA could be eluted in a single step from the protein aggregate. Additionally, isolated plasmid DNA could easily be digested by restriction enzymes and had high functionality in protein expression. Thus, considering both its remarkable simplicity and efficiency in producing sufficiently pure plasmid DNA, the new strategy would emerge a useful tool in modern recombinant technology and therapeutic applications.

Integrin-Supported Fast Rate Intracellular Delivery of Plasmid DNA by Extracellular Matrix Protein Embedded Calcium Phosphate Complexes

Extracellular matrix (ECM) proteins, such as collagen and fibronectin, play vital roles in development and maintenance of hard tissue (bone or tooth) and are, consequently, thoroughly investigated for construction of biomimetic scaffolds in combination with calcium phosphate (CaP) material (the major component of hard tissue) for bone or dental tissue engineering. Realizing the natural affinity of ECM components toward inorganic constituents of hard tissue, we successfully constructed the nanohybrids of DNA/CaP particles with either collagen 1 or fibronectin, which finally possessed the capability of specific recognition of integrin receptor for being swiftly internalized across the plasma membrane, leading to remarkably high transgene expression in mammalian cells. This new approach with precise receptor-specific delivery as well as 10- to 50-fold enhanced efficiency level compared to the classical one, has immediate applications for basic research and large scale production of recombinant therapeutic proteins and looks promising for gene therapy.

A bio-recognition device developed onto nano-crystals of carbonate apatite for cell-targeted gene delivery

The DNA delivery to mammalian cells is an essential tool for analyzing gene structure, regulation, and function. The approach holds great promise for the further development of gene therapy techniques and DNA vaccination strategies to treat and control diseases. Here, we report on the establishment of a cell-specific gene delivery and expression system by physical adsorption of a cell-recognition molecule on the nano-crystal surface of carbonate apatite. As a model, DNA/nano-particles were successfully coated with asialofetuin to facilitate uptake by hepatocyte-derived cell lines through the asialoglycoprotein receptor (ASGPr) and albumin to prevent non-specific interactions of the particles with cell-surface. The resulting composite particles with dual surface properties could accelerate DNA uptake and enhance expression to a notable extent. Nano-particles coated with transferrin in the same manner dramatically enhanced transgene expression in the corresponding receptor-bearing cells and thus our newly developed strategy represents a universal phenomenon for anchoring a bio-recognition macromolecule on the apatite crystal surface for targeted gene delivery, having immediate applications in basic research laboratories and great promise for gene therapy.

High-efficiency gene delivery for expression in mammalian cells by nanoprecipitates of Ca–Mg phosphate

Transfer of desirable genetic sequences into mammalian cells is an essential tool for analysis of gene structure, functions and regulation and industry-based production of therapeutically important proteins and pivotal for gene therapy and DNA vaccination strategies. Considering some severe limitations of viral systems including immunogenicity, carcinogenicity and so on, synthetic nonviral systems are highly desirable in the above applications. However, existing nonviral techniques are extremely inefficient compared to the viral ones. Therefore, we report here on the development of a highly efficient synthetic device for gene delivery and expression into mammalian cells, based on controllable growth of nanoapatite particles. Mg2+ incorporation into the apatite particles caused significant inhibition of particle growth, resulting in retention of nanosized particles which contributed remarkably to the cellular uptake of DNA and its subsequent expression (>10-fold) compared with classical calcium phosphate coprecipitation, one of the most widely used transfection methods.

High ear piercing--a dangerous craze

Ear piercing is a primitive tradition among the human being. It reflects the culture of many religions, tribes, and communities, predominately adopted by the females. We reported a sixteen years old girl with painful swelling of both pinnas for last one month following piercing the pinna. She was treated locally by general practitioner without significant improvement. On examination frank abscess were detected in both pinna. Under general anesthesia incision drainage and deep curettage was done. She was treated with ciprofloxacin 750 mg 12 hourly for 2 weeks and recovery was uneventful. After one month she developed unsightly cauliflower ear. With this report we want to sensitize our community regards the risk of transmission of needle prick diseases and deformity of pinna following ear piercing

Detection of corn intrinsic and recombinant DNA fragments and Cry1Ab protein in the gastrointestinal contents of pigs fed genetically modified corn Bt11

Genetically modified corn has been approved as an animal feed in several countries, but information about the fate of genetically modified DNA and protein in vivo is insufficient. Genetically modified corn Bt11 is developed by inserting a recombinant DNA sequence encoding insecticidal Cry1Ab protein from Bacillus thuringiensis subsp. kurstaki. We examined the presence of corn intrinsic and recombinant cry1Ab gene by PCR, and the Cry1Ab protein by immunological tests in the gastrointestinal contents of five genetically modified corn Bt11-fed and five nongenetically modified corn-fed pigs. Fragments of corn zein (242 bp), invertase (226 bp) and of ribulose-1,5-bisphosphate carboxylase/ oxygenase genes (1,028 bp) were detected in the gastrointestinal contents of both Bt11 and nongenetically modified corn-fed pigs. Fragments of recombinant cry1Ab gene (110 bp and 437 bp) were detected in the gastrointestinal contents of the Bt11-fed pigs but not in the control pigs. Neither corn intrinsic nor cry1Ab gene fragments were detected in the peripheral blood by PCR. The gastrointestinal contents were positive for Cry1Ab protein by ELISA, immunochromatography, and immunoblot; however, these methods did not work for blood and precluded conclusions about any potential absorption of the protein. These results suggest that ingested corn DNA and Cry1Ab protein were not totally degraded in the gastrointestinal tract, as shown by their presence in a form detectable by PCR or immunological tests.

Detection of genetically modified maize DNA fragments in the intestinal contents of pigs fed StarLink CBH351

We tried to detect DNA fragments derived from maize in the intestinal contents of pigs fed genetically modified (GM) StarLink CBH351 maize (SL) or non-GM maize. Intestinal contents of 8 SL and 8 non-GM maize-fed pigs were collected at slaughter, and the genes of the recombinant cry9C and the maize intrinsic zein (Zel) were assayed by polymerase chain reaction (PCR) 3 times with a total of 4 primer pairs of different expected lengths. The cry9C gene (either 103 or 170 bp) was detected in the rectal contents (with a frequency of 25-37.5%) and in the cecal contents (25-50%) of the pigs fed SL. In a similar fashion, the zein (Zel) gene (either 242 or 329 bp) was detected in the rectal contents (with a frequency of 31.3%) and in the cecal contents (25-37.5%) of pigs fed on SL non-GM maize. These results suggested that ingested DNA was not totally degraded, but is present in a form detectable by PCR.

Detection of Cry1Ab protein in gastrointestinal contents but not visceral organs of genetically modified Bt11-fed calves

The fate of insecticidal Cry1Ab protein was examined in the gastrointestinal (GI) contents and visceral organs of calves fed insect-resistant genetically modified maize Bt11. Twelve cross-breed (Japanese black x Holstein) calves were fed either Bt11 or non-genetically modified isoline maize for 90 d. Peripheral blood, rumen juice and feces were collected fortnightly, and GI contents and visceral organs were collected at slaughter at the end of the experiment. Samples were checked for Cry1Ab protein by immunological methods, and visceral organs were examined pathologically. Trace amounts of Cry1Ab protein were detected in the GI contents but not in the liver, spleen, kidney, muscle or mesenteric lymph nodes. No lesions were observed pathologically. Cry1Ab protein in the feces was degraded quickly at atmospheric temperature. These results suggested that only a trace amount of Cry1Ab protein survived passage through the GI tract but was not transferred to liver, spleen, kidney, lymph nodes or muscles.

Galactosylated chitosan-graft-poly(ethylene glycol) as hepatocyte-targeting DNA carrier

Lactobionic acid bearing galactose group was coupled with chitosan for liver specificity, and poly(ethylene glycol) (PEG) was grafted to galactosylated chitosan (GC) for stability in water and enhanced cell permeability. Complex formation of galactosylated chitosan-graft-PEG (GCP)/DNA complexes was confirmed by agarose gel electrophoresis. Compared to GC/DNA complex, the stability of GCP/DNA complex could be enhanced. Particle sizes of GCP/DNA complexes decreased as the charge ratio of GCP to DNA increased and had a minimum value around 27 nm at the charge ratio of 5. Conformational change of DNA did not occur after complex formation with GCP compared to conformation of DNA itself. GCP/DNA complexes were only transfected into Hep G2 having asialoglycoprotein receptors (ASGR), indicative of specific interaction of ASGR on cells and galactose ligands on GCP.

Rapid detection of infectious laryngotracheitis virus by standardization of polymerase chain reaction targeting a relatively conserved region of the thymidine kinase gene

Infectious laryngotracheitis is an acute upper respiratory tract infection of chickens caused by infectious laryngotracheitis virus. The study was conducted to standardize the polymerase chain reaction targeting a relatively conserved region of the thymidine kinase gene for the rapid detection of infectious laryngotracheitis virus. The vaccine samples were collected from two renowned company of Bangladesh. DNA was extracted from diluted vaccine samples by using Wizard® Genomic DNA purification kit and thymidine kinase gene was amplified by using PCR system 9600 Thermocycler. Two vaccine samples were positively amplified by polymerase chain reaction. A procedure was developed for rapid detection of infectious laryngotracheitis virus by polymerase chain reaction of the conserved region of viral thymidine kinase gene containing DNA fragments. The results obtained in this study suggested that the polymerase chain reaction procedure could serve as a fast and sensitive method for the detection of vaccine strains of infectious laryngotracheitis viruses.   Key words: Infectious laryngotracheitis virus; viral thymidine kinase (TK) gene; polymerase chain reaction DOI: http://dx.doi.org/10.3329/ujzru.v29i1.9468 UJZRU 2010; 29(1): 61-64

Seroprevalence and pathological study of Salmonella infections in layer chickens and isolation and identification of causal agents

The present research work was conducted to study about the seroprevalence and pathology of Salmonella infections in layer chickens of Dhaka and Gazipur regions of Bangladesh and to isolate and characterize Salmonellae from layer chickens during the period from January to May 2006. The used materials were blood sample, cloacal and liver swabs from live and dead birds respectively, and visceral organs (liver, lungs, spleen and intestine). The used methods were serum plate agglutination (SPA) test; necropsy and histopathology; cultural, morphological and biochemical test. The overall seroprevalence was 43.4%. During necropsy, congested and enlarged liver with focal necrosis, haemorrhagic and discoloured ovary with stalk formation and mild haemorrhagic to catarrhal enteritis in intestine were detected. Microscopically, the liver showed congestion, focal necrosis with multifocal infiltration of histiocytes in liver parenchyma. In ovum, infiltration of leukocytes, bacterial colony, RE cell proliferation and fibrinoid necrosis were recorded. The intestinal mucosa exhibited infiltration of mononuclear cells in mucosa, submucosa as well as muscularis mucosa. A total of 33 (21.02%) Salmonellae from live and dead birds were isolated. The isolation rate of Salmonellae was higher in seronegative (31.6%) group than seropositive (3.2%) group. Out of 33 Salmonella isolates, 25 were S. pullorum, 3 were S. gallinarum and the rest 5 were motile Salmonellae. The isolates obtained in the study may be investigated for serotyping, pathogenesis study, antibiogram and vaccine production in future. Key words: Seroprevalence, histopathology, isolation, identification, Salmonella, chickensDOI = 10.3329/bjvm.v4i2.1288Bangl. J. Vet. Med. (2006). 4 (2): 79–85

Isolation and Characterization of Enterobacteria Associated with Health and Disease in Sonali Chickens

Bacteriological examination on intestinal swabs of 30 apparently healthy and 30 sick / dead Sonali chickens (Fayoumi hen × RIR cock), aged between 25 to 60 weeks were carried out to determine the enteropathogens associated with health and disease, during the period from March to October 2003. These birds of either sex and reared under semi-scavenging system under the SLDP-2 project area in the district of Feni. The 60 swabs were collected at slaughter / necropsy in sterile nutrient and tetrathionate broth. In addition, the gross tissue changes of the sick / dead birds were recorded. The prevalent bacterial flora in intestinal swabs were Salmonella (33.33%), E. coli (95.0%), Staphylococcus (51.66%), Streptococcus (40%) and Pasteurella multocida (3.33%) of which Salmonella (36.66%) and E. coli (26.66%) were associated with marked pathological lesions. The isolated enteropathogens and their associated gross and histopathological changes are described and discussed. It may be concluded from this study that the enteric bacteria usually remain as clinically overt infection and do not produce clinical disease unless or until other factors are involved. Key words: Enterobacteria; apparently healthy chickens; sick/dead chickens; pathology doi: 10.3329/bjvm.v2i1.1928 Bangl. J. Vet. Med. (2004). 2 (1) : 15-21

Avian Salmonella Infection: Isolation and Identification of Organisms and Histopathological Study

The Present study was performed in the Department of Pathology, BAU, Mymensingh during the period from January to December 2004. The study was conducted to determine the occurrence and pathology of pullorum disease, fowl typhoid and salmonellosis (paratyphoid infection) in dead chickens at necropsy in Mymensingh district of Bangladesh. A total of 70 samples (liver, ovary and intestine) were collected for isolation of bacteria in different media, and identification was performed based on the staining, cultural and biochemical properties of Salmonella spp. Routine histopathological method was used for the detection of tissue level alterations in Salmonella infected cases. Grossly, in all the infected cases the liver was enlarged and congested and in few cases, liver discoloration with focal necrosis. Old raised hemorrhages in the caecal tonsil and congested deformed ova were other important findings. There was catarrhal inflammation in the intestine. Microscopically, the section of livers showed congestion, hemorrhages, focal necrosis with infiltration of mononuclear cells. The pulmonary lesions consisted of sero-fibrinous exudation with mononuclear cell infiltration. The intestinal mucosa exhibited congestion, hemorrhages and infiltration of plasma cells, heterophils and macrophages. Out of 70 samples, 8 isolates were identified as Salmonella (11.42 %). Of them, five isolates were identified as Salmonella gallinarum, causative agent of fowl typhoid, one isolate was characterized as Salmonella pullorum, causative agent of pullorum disease and other two motile salmonella were identified as paratyphoid infection. Keywords: Fowl typhoid, pullorum disease, paratyphoid, histopathology, isolation, identification doi:10.3329/bjvm.v4i1.1518 Bangl. J. Vet. Med. (2006). 4 (1): 07-12