Recombinant expression and characterization of Canine circovirus capsid protein for diagnosis

Canine circovirus (CanineCV) is a contagious virus that causes severe gastroenteritis, diarrhea, respiratory disease, and vasculitis, often resulting in fatality among infected dogs. In this study, a recombinant Capsid protein (rCap) of CanineCV was expressed in the Escherichia coli (E. coli) Rosetta (DE3) pLysS host cell, followed by affinity purification, and then analyzed by SDS-PAGE, revealing a molecular weight of approximately 31 kDa. The antigenicity of the CanineCV rCap protein was confirmed through recognition by a rabbit anti-CanineCV rCap protein polyclonal antibody (PoAb). Additionally, the reactivity and specificity of this PoAb were assessed using indirect enzyme-linked immunosorbent assay (ELISA) and Western blot analysis before applying in an immunohistochemistry (IHC), namely, immunoperoxidase detection. The immunoperoxidase assay using rabbit anti-CanineCV rCap protein PoAb demonstrated that the CanineCV Cap protein was predominantly located in immune cells, especially lymphocytes and macrophages, within the spleen, lung, tracheobronchial lymph nodes, small intestine, and kidney. Similarly, the Cap protein was also found in pneumocytes in the lung and renal tubular epithelial cells in the kidney. These findings reflected the biological activity and cell tropism of the virus. Therefore, the recombinant Cap protein and its PoAb could be used for the development of a valuable diagnostic tool for CanineCV detection.

RPA-CRISPR/Cas12a assay for the diagnosis of bovine Anaplasma marginale infection

Anaplasma marginale infection is one of the most common tick-borne diseases, causing a substantial loss in the beef and dairy production industries. Once infected, the pathogen remains in the cattle for life, allowing the parasites to spread to healthy animals. Since clinical manifestations of anaplasmosis occur late in the disease, a sensitive, accurate, and affordable pathogen identification is crucial in preventing and controlling the infection. To this end, we developed an RPA-CRISPR/Cas12a assay specific to A. marginale infection in bovines targeting the msp4 gene. Our assay is performed at one moderately high temperature, producing fluorescent signals or positive readout of a lateral flow dipstick, which is as sensitive as conventional PCR-based DNA amplification. This RPA-CRISPR/Cas12a assay can detect as few as 4 copies/μl of Anaplasma using msp4 marker without cross-reactivity to other common bovine pathogens. Lyophilized components of the assay can be stored at room temperature for an extended period, indicating its potential for field diagnosis and low-resource settings of anaplasmosis in bovines.

Molecular occurrence and genetic diversity of Ehrlichia canis in naturally infected dogs from Thailand

Canine monocytic ehrlichiosis is cause by Ehrlichia canis resulting in hematologic disorders and severe clinical signs. The aim of this study was to scrutinize the molecular detection and genetic diversity of E. canis based on the trp36 gene in dogs from Thailand's northern and central regions. A total of 120 dogs blood samples were amplified for trp36 gene of E. canis using the polymerase chain reaction (PCR). Forty-seven out of 120 dog blood samples (39.16%, 47/120) were positive for E. canis the trp36 DNA with 790 bp of PCR amplicon size. The factor significantly associated with E. canis infection is animal housing status (p < 0.05). Sequence and phylogenetic analysis showed that E. canis trp36 gene of Thailand isolates was clustered into 1st clade with similarity ranging from 95.65 to 100% together with the US genogroup. The 14 haplotypes of the trp36 gene shown in TCS network exhibited that haplotype #1-4 was found in Thailand. The entropy analysis of the trp36 gene illustrated 751 polymorphic sites and 271 entropy peaks of nucleic and amino acid sequences, respectively. Hence, these findings are crucial for better understanding the epidemiology of Ehrlichia infection and could be helpful for implementing control measures in Thailand.

Ehrlichia canis: Molecular characterization and genetic diversity based on the p28 and trp36 genes

Ehrlichia canis is a common tick-borne intracellular pathogen causing canine monocytic ehrlichiosis (CME) in dogs worldwide. The aims of this study were to investigate the genetic diversity and antigenicity of E. canis based on the p28 and trp36 genes in dogs in Thailand. The E. canis p28 and trp36 genes were amplified by the polymerase chain reaction (PCR) and cloned for sequencing and bioinformatic analyses. 36% (44/120) of dog blood samples were positive for E. canis DNA consisting of p28 (31%, 14/44) and trp36 (69%, 30/44) genes with 792 and 882 bp of PCR products size, respectively. The E. canis TRP36 from all Thailand sequences exhibited encoded nine amino acids (TEDSVSAPA) with 11 copies of tandem repeats along the sequences. The phylogenetic trees of E. canis, using the p28 and trp36 genes, exhibited that the Thailand isolates fell into two clades and one clade with similarity ranging from 55.95 to 100% and 100%, respectively. The results of diversity analysis revealed 10 and 20 haplotypes of the p28 and trp 36 genes, respectively. The entropy analysis of the p28 and trp36 nucleic acid sequences showed 442 and 1321 high entropy peaks respectively, whereas those of the P28 and TRP36 amino acid sequences showed 477 and 388 high entropy peaks, respectively. For B-cell epitopes analysis, the conserved amino acid of P28 and TRP36 sequences has been also demonstrated. Therefore, the results could be utilized to improve the understanding of phylogenetic relationship, genetic diversity and antigenicity of E. canis Thailand isolates.

Molecular characterization and genetic diversity of Babesia bovis and Babesia bigemina of cattle in Thailand

Babesia bovis and B. bigemina are the most common tick-borne parasites that cause bovine babesiosis which effects livestock production, leading to economic losses in tropical and subtropical areas of the world. The aims of this study were to determine the molecular detection, genetic diversity and antigenicity prediction of B. bovis based on spherical body protein 2 (sbp-2) gene and B. bigemina based on rhoptry-associated protein 1a (rap-1a) gene in cattle in Thailand. By PCR assay, the molecular detection of B. bovis and B. bigemina infection revealed levels of 2.58% (4/155) and 5.80% (9/155), respectively. The phylograms showed that B. bovis sbp-2 and B. bigemina rap-1a sequences displayed 5 and 3 clades with similarity ranging between 85.53 to 100% and 98.28 to 100%, respectively, when compared within Thailand strain. Diversity analysis of sbp-2 and rap-1a sequences showed 18 and 4 haplotypes, respectively. The entropy analysis illustrated 104 and 7 polymorphic sites of sbp-2 and rap-1a nucleic acid sequences, respectively, while those of sbp-2 and rap-1a amino acid sequences showed 46 and 4 high entropy peaks, respectively. Motifs analysis exhibited the distribution and conservation among sbp-2 and rap-1a sequences. The continuous and discontinuous B-cell epitopes have also been evaluated in this work. Therefore, our findings may be used to ameliorate the understanding inputs of molecular phylogeny, genetic diversity and antigenicity of B. bovis and B. bigemina Thailand stains.

A first attempt at determining the antibody-specific pattern of Platynosomum fastosum crude antigen and identification of immunoreactive proteins for immunodiagnosis of feline platynosomiasis

Background and Aim:

Feline platynosomiasis, also known as lizard poisoning, is a feline hepatic disease caused by the parasitic trematode Platynosomum fastosum. Since this helminth resides in biliary ducts and gallbladder, the heavy infection can lead to failure of the hepatobiliary system and can be associated with cholangiocarcinoma. The primary diagnostic tool currently used is conventional fecal microscopy. However, low sensitivity of detection could occur in the case of light infection or biliary obstruction. This study aimed to determine the antibody-specific pattern of P. fastosum crude antigen and to identify immunoreactive proteins to develop the immunodiagnostic techniques.

Materials and Methods:

We investigated potential antigens specific to P. fastosum infection using western blotting. Forty-six samples of cat serum, including 16 P. fastosum-infected sera, eight healthy control sera, and 22 sera infected with other endoparasites were used. The sensitivity, specificity, positive predictive value, and negative predictive value of each band were calculated. Immunoreactive bands with high diagnostic values were further analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify the protein components.

Results:

Using immunoblotting, three proteins of 72 kDa, 53 kDa, and 13 kDa were found to be immunogenic. LC-MS/MS identified these proteins as a 70 kDa heat shock protein, a hypothetical protein (CRM22_002083) (adenosine triphosphate synthase subunit beta), and histone H2B, respectively.

Conclusion:

This study is the first to reveal three proteins that could be candidates for developing diagnostic tools for feline platynosomiasis.

First study on molecular detection of three major canine tick-borne pathogens in subclinically infected dogs in Chiang Mai, Thailand

Background and Aim:

Canine tick-borne pathogens (CTBPs) are an important cause of morbidity in dogs in Thailand. This study aimed to evaluate the occurrence of three CTBPs in clinically normal, owned dogs to understand the risk for the general canine population. We also examined sex, age, tick infestation, and packed cell volume (PCV) of the animals in association with active infection of the CTBPs.

Materials and Methods:

A total of 139 dogs were included in the study. Blood samples were collected for thin blood smear, PCV and nested polymerase chain reaction (PCR) assay. Statistical analyses were performed to examine the association between individual factors and CTBP infection status determined by PCR. In addition, sensitivity, specificity, and Cohen’s kappa were calculated to assess the utility of routine blood smear.

Results:

The PCR results showed that 31 dogs (22.3%) were infected with at least one of the three pathogens. The occurrence rate for Ehrlichia canis, Anaplasma platys, and Hepatozoon canis was 2.2% (3/139), 18.7% (24/139), and 2.8% (4/139), respectively. There were two cases of coinfection with A. platys and E. canis. The univariate analyses did not yield any associations between recorded variables and the active infection. Microscopic examination showed good sensitivity and agreement only for H. canis (Sn: 75%, 95% confidence interval: 24.9-98.7, k=0.85).

Conclusion:

Our findings confirmed the endemicity of the CTBPs in owned canine population in the study site. In-depth epidemiological investigation would be warranted to elucidate environmental risk factors for CTBP infection.

Molecular genetic diversity and bioinformatic analysis of Leucocytozoon sabrazesi based on the mitochondrial genes cytb, coxI and coxIII and co-infection of Plasmodium spp

Leucocytozoon sabrazesi is an intracellular haemoprotozoan parasite responsible for leucocytozoonosis, which is transmitted by insect vectors and affects chickens in tropical and subtropical areas in many countries. It causes huge economic losses due to decreased meat and egg production. In the present study, we used nested PCR to determine the genetic diversity of L. sabrazesi based on the cytb, coxI, coxIII and concatenated genes in chickens in Thailand. In addition, we found co-infections between L. sabrazesi and Plasmodium spp. (P. gallinaceum or P. juxtanucleare) in chickens that were not identified by microscopic examination of blood smears. The phylogenetic analysis indicated that L. sabrazesi cytb and coxIII genes were conserved with similarity ranging from 99.9 to 100% and 98 to 100%, respectively whereas the coxI gene was diverse, with similarities ranging from 97 to 100%. These findings ascertained the nucleotide analysis of the cytb, coxI, coxIII and concatenated sequences in which 4, 8, 10 and 9 haplotypes were found, respectively. In addition, it was found that the large number of synonymous substitutions and conservative amino acid replacements in these mitochondrial genes occurred by non-synonymous substitution. The evolutionary analysis of the K_a/K_s ratio supported purifying selection and the negative values of both Fu’s Fs and Tajima’s D indicate selective sweep especially for the coxI gene. The entropy and Simplot analysis showed that the genetic variation in populations of Plasmodium spp. was higher than in Leucocytozoon. Hence, the nucleotide sequences of three mitochondrial genes could reflect the evolutionary analysis and geographic distribution of this protozoan population that switches hosts during its life cycle.

Molecular discrimination and genetic diversity of three common tick-borne pathogens in dogs in Thailand

There was little information regarding the occurrence of canine vector-borne disease (CVBDs) in shelter dogs in Thailand. This work is the first report regarding a molecular method used to determine the occurrence and genetic diversity of three canine tick-borne pathogens (TBPs) (Hepatozoon canis, Anaplasma platys and Ehrlichia canis) in blood samples from 275 shelter dogs in the north and central areas of Thailand. The PCR results based on the 18S rRNA and 16S rRNA genes showed that 71 (25.82%) dogs were positive for at least a TBP. The overall occurrence rates of H. canis, A. platys and E. canis infections were 1.81, 16.36 and 7.64%, respectively. For the phylogenetic analysis, A. platys 16S rRNA gene was genetically diverse, while H. canis 18S rRNA and E. canis 16S rRNA genes were conserved. The haplotype diversity exhibited 12 and 2 haplotypes as well as 78 and 178 polymorphic sites of A. platys and E. canis 16S rRNA genes, respectively. Our findings could be used to improve the understanding of phylogeny and genetic diversity of TBP rRNA genes and used to ameliorate the diagnosis and control programmes for the diseases in Thailand.

Molecular characterization of Anaplasma marginale based on the msp1a and msp1b genes

Anaplasma marginale is an intracellular rickettsial bacterium causing anaplasmosis in ruminants. A. marginale is transmitted biologically by ticks and mechanically by blood-sucking vectors. Anaplasmosis occurs in tropical and subtropical areas of the world. This disease causes huge economic losses due to decreasing meat yield and milk production. The aims of this study were to determine the genetic diversity and antigenicity of A. marginale based on the msp1a and msp1b genes in cattle in Thailand. The A. marginale msp1a and msp1b genes were amplified by the polymerase chain reaction (PCR). There have been four copies of MSP1a tandem repeats among A. marginale Thailand strain, and thirteen different MSP1a tandem repeats were found including repeats B, 25, 27, M, 3, S, C, H, β, 80, 4, TH1 and TH2. Notably, this study showed two copies of the novel conserved tandem sequences namely Thailand Type 1 (TH1) and Type 2 (TH2). The phylogenetic analysis revealed that A. marginale msp1a and msp1b genes were genetically diverse and showed 9 and 5 clades with similarity ranging from 98 to 100% and 79.5 to 100%, respectively, when compared within the isolates of this study. The results of diversity analysis showed 18 and 16 haplotypes of the msp1a and msp1b genes, respectively. The entropy analyses of msp1a and msp1b nucleic acid sequences showed 39 and 900 high entropy peaks with values ranging from 0.35 to 0.85 and from 0.41 to 1.48, respectively, while those of MSP1a and MSP1b amino acid sequences exhibited 75 and 72 high entropy peaks with values ranging from 0.35 to 1.06 and from 0.41 to 1.55, respectively. In addition, B-cell and T-cell epitopes have also been investigated in this study. Hence, our results could be employed to improve the insight input of molecular phylogenetics, genetic diversity and antigenicity of A. marginale Thailand strain.

Molecular detection and genetic diversity of Leucocytozoon sabrazesi in chickens in Thailand

Leucocytozoon sabrazesi is the intracellular protozoa of leucocytozoonosis, which is transmitted by the insect vectors and affects chickens in most subtropical and tropical regions of the globe, except South America, and causing enormous economic losses due to decreasing meat yield and egg production. In this study, L. sabrazesi gametocytes have been observed in the blood smears, and molecular methods have been used to analyse the occurrence and genetic diversity of L. sabrazesi in blood samples from 313 chickens raised in northern, western and southern parts of Thailand. The nested polymerase chain reaction (nested PCR) assay based on the cytb gene revealed that 80.51% (252/313) chickens were positive of L. sabrazesi. The phylogenetic analysis indicated that L. sabrazesi cytb gene is conserved in Thailand, showed 2 clades and 2 subclades with similarity ranged from 89.5 to 100%. The diversity analysis showed 13 and 18 haplotypes of the sequences from Thailand and from other countries, respectively. The entropy analyses of nucleic acid sequences showed 26 high entropy peaks with values ranging from 0.24493 to 1.21056, while those of amino acid sequences exhibited 5 high entropy peaks with values ranging from 0.39267 to 0.97012. The results; therefore, indicate a high molecular occurrence of L. sabrazesi in chicken blood samples with the associated factors that is statistically significant (p < 0.05). Hence, our results could be used to improve the immunodiagnostic methods and to find appropriate preventive control strategies or vaccination programs against leucocytozoonosis in order to mitigate or eliminate the harmful impact of this infection on chicken industry.

Population and distribution of wild Asian elephants (Elephas maximus) in Phu Khieo Wildlife Sanctuary, Thailand

Background

The populations of wild Asian elephants (Elephas maximus) have increased recently after a period of worldwide decline in protected areas. It is important to understand the dynamics and distribution of the remaining populations to ensure their conservation and prevent human-elephant conflicts.

Methods

We monitored the population distribution of elephants between 2016 and 2019 in the Phu Khieo Wildlife Sanctuary, Thailand. We set one hundred forty-nine camera trap locations; cameras recorded 38,834 photos over 6,896 trap nights. Elephants were captured in 4,319 photographs. The maximum entropy modeling software MaxEntwas used to identify elephants’ habitat preferences within 49 of the 149 total camera trap locations according to five environmental factors.

Results

One hundred fourteen elephants were identified. We identified 30 adult males, 43 adult females, 14 sub-adult males, nine sub-adult females, 11 juveniles, and seven calves. The age structure ratio based on adult femaleswas 0.7:1:0.3:0.2:0.3:0.2, and the ratio of reproductive ability between adult females, juveniles, and calves was 1:0.2:0.1. A suitable elephant habitat was determined to be 1,288.9 km² using Area Under the Curve (AUC). An AUC = 0.061 indicated good performance. Our model classified habitat preferences associated with elevation, forests, salt licks, human activity, and slope.

Conclusions

According to our probability map this sanctuary can provide a suitable habitat for elephants. Our results indicate that effective management practices can protect wild Asian elephants in the region and reduce conflict between humans and elephants.

Partial DnaK protein expression from Coxiella-like endosymbiont of Rhipicephalus annulatus tick

Q fever is one of the most important zoonotic diseases caused by the obligate intracellular bacteria, Coxiella burnetii. This bacterial infection has been frequently reported in both humans and animals, especially ruminants. Ticks are important ectoparasite and serve as reservoir hosts of Coxiella-like endosymbionts (CLEs). In this study, we have attempted to express chaperone-coding genes from CLEs of Rhipicephalus annulatus ticks collected fromcow path. The partial DnaK coding sequence has been amplified and expressed by Escherichia coli. Amino acid sequences have been analyzed by MS-MS spectrometry and the UniProt database. Despites nucleotide sequences indicating high nucleotide variation and diversity, many nucleotide substitutions are synonymous. In addition, amino acid substitutions compensate for the physicochemical properties of the original amino acids. Immune Epitope Database and Analysis Resource (IEDB-AR) was employed to indicate the antigenicity of the partial DnaK protein and predict the epitopes of B-and T-cells. Interestingly, some predicted HLA-A and B alleles of the MHC-I and HLA-DR alleles belonging to MHC-II were similar to T-cell responses to C. burnetii in Q fever patients. Therefore, the partial DnaK protein of CLE from R. annulatus could be considered a vaccine candidate and immunogenic marker with future prospects.

The anthelmintic potentials of medicinal plant extracts and an isolated compound (rutin, C27H30O16) from Terminalia catappa L. against Gastrothylax crumenifer

Paramphistomosis is a pathogenic disease that occurs frequently in tropical and subtropical countries including Thailand. This disease is affected in the parasites causing severe gastrointestinal disorders and death in infected animals. In the present study, we examined the anthelmintic efficacy of albendazole (ABZ) and crude plant extracts from barks of Bombax ceiba L., Diospyros rhodocalyx Kurz. and Vitex glabrata R.Br., and leaves of Terminalia catappa L. and Cassia alata L. against Gastrothylax crumenifer. The hightest anthelmintic activity on the parasites after 24 h incubation was observed in the n-butanol extract of T. catappa leaf. In this study, fractionation bioassay of n-butanol extract of T. catappa leaf was conducted to both separation and discrimination of rutin served as a new efficient compound (LC₅₀ = 28.96; LC₉₀ = 88.75 μg/mL) against G. crumenifer. This compound was confirmed by ¹H nuclear magnetic resonance (¹H NMR), ¹³C NMR, infrared (IR) and ultraviolet (UV) spectra as well as mass spectra data. The rutin-treated parasites with all dosages showed swift decrease of the motility and the relative motility (RM) and survival index (SI) were decreased obviously from 3 h until flukes were killed after 12 h of incubation. When observed with light microscopy, the parasites showed the earliest change in a limited region of the tegument. When observed by scanning electron microscopy, the parasites' tegument exhibited similar sequences of surface changes after treatments with rutin and ABZ, but less severity in ABZ treatment. The sequences of changes comprised swelling of folds and ridges, formation of blebbing, rupturing of blebs, erosions, lesions and the tegument demolition. Hence, rutin could be considered as the potential anthelmintic agent for treatment of paramphistomosis.

Molecular detection and genetic diversity of Anaplasma marginale based on the major surface protein genes in Thailand

Anaplasma marginale is the rickettsial agent of anaplasmosis, a tick-borne disease, which affects cattle and other ruminants in tropical and subtropical areas of the world, and causing huge economic losses because of decreasing meat and milk production. In the present study, molecular methods have been used to determine the occurrence and genetic diversity of A. marginale, based on the genes encoding the major surface proteins (msps) genes, in blood samples from 520 cattle and 121 buffaloes in the north and northeastern regions of Thailand. The polymerase chain reaction (PCR) results based on the msp4 gene indicated that 66 (10.30%) cattle were positive for A. marginale, whereas no positive result was obtained from buffaloes. The phylogenetic analysis based on the maximum likelihood method using 13, 29 and 27 nucleotide sequences from msp2, msp4, msp5 clones, respectively, revealed that the sequences detected in this study are obviously distributed in different clusters. The sequence analysis demonstrated that msp2 gene is genetically diverse, while msp4 and msp5 genes are conserved in Thailand. These findings corroborated the diversity analysis of the same sequences, which showed 13, 27 and 27 haplotypes of the msp2, msp4 and msp5 genes, respectively. In addition, the entropy analyses of amino acid sequences exhibited 127, 75 and 51 high entropy peaks with values ranging from 0.27119 to 2.45831, from 0.14999 to 2.17552 and from 0.15841 to 1.05453 for MSP2, MSP4 and MSP5, respectively. Therefore, the results indicate a low molecular occurrence of A. marginale in cattle blood samples in Thailand. From these results; however, a high degree of genetic diversity was observed in the analyzed A. marginale population. Hence, our finding could be used to improve the immunodiagnostics and vaccination programs for anaplasmosis.

Monitoring body condition score of reintroduced banteng (Bos javanicus D'Alton, 1923) into Salakphra Wildlife Sanctuary, Thailand

Background

Banteng (Bos javanicus d’Alton 1823) are an endangered species, highly sensitive to habitat structure and quality. In many areas, banteng were extinct and needed to be reintroduced to restore their population. Thus, understanding the responses of body condition of reintroduced banteng to their habitat was important for ensuring the sustainability of a reintroduction program. The aim of the present study was to evaluate the body condition of banteng after reintroduction into the Salakphra Wildlife Sanctuary in Thailand based on photographs from camera-traps carried out between July 2016 and November 2018.

Methods

Seven banteng were bred at the Khao Nampu Nature and Wildlife Education Center and systematically reintroduced into the Salakphra Wildlife Sanctuary in December 2015 (four) and July 2016 (three). The seven reintroduced adults and two newborns (from the 2015 group) were captured via camera traps in 2018. The body condition scoring (BCS) obtained from these photographs was used to identify the individual performance of all seven adults after their reintroduction.

Results

The BCS scores in reintroduced adult banteng, both males and females, (between 5 and 7 years old) increased significantly over time after reintroduction into a natural habitat (p < 0.05), although the BCS scores in females were not significantly different between the second and third years (p > 0.05).

Conclusions

The results from the present study suggest that camera traps are a practical tool to assess the BCS of reintroduced banteng, and can be used to monitor their condition post-release. These techniques may be appropriate for translocation programs elsewhere.

Recombinant expression and characterization of major surface protein 4 from Anaplasma marginale

Anaplasma marginale is the rickettsia which causes the bovine anaplasmosis. The distribution of A. marginale is both tropical and subtropical regions of the world. The major surface protein 4 (MSP4) of this parasite was identified as an immunodominant protein. In this study, the full length of DNA encoding A. marginale MSP4 (AmMSP4) was cloned from the parasites. The open reading frame of msp4 coding sequence of Thailand strain is 849 bp. Phylogenetic analysis revealed that the msp4 coding sequence of A. marginale was highly conserved when compared with Anaplasma phagocytophilum. The recombinant plasmid was further transformed into the BL21-CodonPlus (DE3)-RIPL competent cells for over-expression of the recombinant major surface protein 4 of A. marginale (rAmMSP4). Sera from rabbit immunized with rAmMSP4 and from cattle infected with A. marginale were used to study the antigenicity of rAmMSP4 (35 kDa) and AmMSP4 (31 kDa). Both rAmMSP4 and AmMSP4 were recognized by these sera showing that recombinant and native AmMSP4 have conserved epitopes. Localization of Anaplasma parasites by immunofluorescence showed these parasites are distributed on both the membrane and the outside of infected erythrocytes. Regarding antigenicity, recombinant MSP4 could be used for immunodiagnostic purposes and as a possible vaccine candidate against anaplasmosis.

The expression and distribution of a leptin receptor in the central nervous system, digestive organs, and gonads of the giant freshwater prawn, Macrobrachium rosenbergii

In the present study, the presence and distribution of leptin receptor (LEP-R) in central nervous system, digestive organs, gonads of giant freshwater prawn, Macrobrachium rosenbergii, were investigated with Western blot and immunohistochemistry. By Western blot a LEP-R with a molecular weight (MW) of 100 kDa was detected in the brain, thoracic ganglia, abdominal ganglia, hepatopancreas, all parts of the gastrointestinal tract, ovaries, and testes. In hepatopancreas and foregut, another intense positive band was detected at molecular weight of 30 kDa, which could be an isotype of LEP-R. By immunohistochemistry, LEP-R-ir was detected in the neurons, and neuropils in the brain, thoracic ganglia, and abdominal ganglia. In the gastrointestinal tract, there was intense LEP-R-ir in the apical part of the epithelial cells of the foregut, midgut, and hindgut. In addition, LEP-R-ir was found in the Restzellen(R)cells and Fibrillenzellen(F) cells in the hepatopancreas. In the ovary, LEP-R-ir was detected in early stage of oocytes and mature oocytes. Intense LEP-R-ir was observed in spermatogonia and spermatocytes of the small and orange claw male prawns. In addition, LEP-R was seen in the high epithelium of spermatic ducts from all male morphotypes. In summary, the detection of the LEP-R-ir suggests the existence of a LEP-R in several organs of M. rosenbergii. Through binding with leptin peptide, LEP-R may be an important signaling molecule that has critical functions in modulating and controlling food intake, energy expenditure, and reproduction in this prawn.

Immunodiagnosis of Fasciola gigantica Infection Using Monoclonal Antibody-Based Sandwich ELISA and Immunochromatographic Assay for Detection of Circulating Cathepsin L1 Protease

BACKGROUND

Tropical fasciolosis caused by Fasciola gigantica infection is one of the major diseases infecting ruminants in the tropical regions of Africa and Asia including Thailand. Parasitological diagnosis of fasciolosis is often unreliable and possesses low sensitivity. Therefore, the detection of circulating parasite antigens is thought to be a better alternative for diagnosis of fasciolosis, as it reflects the real parasite burden.

METHODS

In this study, we have produced a monoclonal antibody (MoAb) against recombinant F. gigantica cathepsin L1 (rFgCatL1), and developed both sandwich enzyme-linked immunosorbent assay (sandwich ELISA) and immunochromatographic (IC) test for rapid detection of circulating cathepsin L1 protease (CatL1) in the sera from mice experimentally and cattle naturally infected with Fasciola gigantica. MoAb 4E3 and biotinylated rabbit anti-recombinant CatL1 antibody were selected due to their high reactivities and specificities.

RESULTS

The lower detection limits of sandwich ELISA and IC test were 3 pg/ml and 0.256 ng/ml, respectively. Sandwich ELISA and IC test could detect F. gigantica infection from day 1 to 35 post infection. In experimental mice, the sensitivity, specificity and accuracy were 95%, 100% and 98.6% (for sandwich ELISA), and 93%, 100% and 98.2% (for IC test), while in natural cattle they were 98.3%, 100% and 99.5% (for sandwich ELISA), and 96.7%, 100% and 99.1% (for IC test).

CONCLUSIONS

These two assay methods showed high efficiencies and precisions for diagnosis of fasciolosis by F. gigantica.

Surface topography and ultrastructural architecture of the tegument of adult Carmyerius spatiosus Brandes, 1898

Adult Carmyerius spatiosus or stomach fluke has an elongate, cylindrical-shaped, straight to slightly curved body, with conical anterior end and truncated posterior end. The worm measures about 8.7-11.2mm in body length and 2.3-3.0mm in body width across the mid-section. When observed by SEM, the tegumental surface in all part of the body appears highly corrugated with ridges and furrows, and having no spines. The ventral surface has more complex corrugation than those of the dorsal surface. Both anterior and posterior suckers have thick edges covered with transverse folds and appear spineless. The genital pore is located at the anterior part of the body. There are two types of sensory papillae on the surface: type 1 is bulbous in shape with nipple-like tips; type 2 has a similar shape with short cilia on the tip. The dorsal surface exhibits similar surface features, but papillae appear less numerous and are smaller. When observed by TEM, the tegument is divided into four layers. The first layer includes the ridges and furrows which are covered by a trilaminate membrane underlined by a dense lamina and coated externally with the glycocalyx. The second layer of the tegument is a narrow region of cytoplasm that contains high concentrations of ovoid electron lucent tegumental granules (TG1), and disc-shaped electron dense tegumental granules (TG2) as well as lysosomes. TG1 close to the surface invariably exocytose their content into bottoms of the ridges, while some TG2 are fused and have their membrane joined up with the surface membrane. The third layer is the widest middle area of the tegument which contains numerous and evenly distributed mitochondria. Both TG1 and TG2 granules are present but in much fewer number than in the first and second layers. The fourth layer is the innermost zone that rests on and couples with a thick basal lamina. The cytoplasm in this layer is loosely packed and contains numerous infoldings of the basal plasma membrane with closely associated mitochondria. It also contains fairly large numbers of TG1 and TG2 granules which are produced and transported to the tegument by one type of tegumental cells lying in rows underneath the muscular layers.

Alterations in the levels and distribution of octopamine in the central nervous system and ovary of the Pacific white shrimp, Litopenaeus vannamei, and its possible role in ovarian development

Octopamine (OA) is a major neurotransmitter that has not been studied in the Pacific white shrimp, Litopenaeus vannamei. Therefore, we investigated changes in OA levels, its distribution in regions of the central nervous system (CNS) and ovary during the ovarian maturation cycle, as well as its possible role in regulating ovarian maturation. OA exhibited the highest concentration in the brain and thoracic ganglia at ovarian stage II, and then declined to the lowest concentration at ovarian stages III and IV. In the cerebral ganglia, OA-immunoreactivity (OA-ir) was present in neurons of clusters 6, 17, the anterior and posterior medial protocerebral, olfactory, antenna II, and tegumentary neuropils. In the circumesophageal, subesophageal, thoracic ganglia and abdominal ganglia, OA-ir was detected in several neuropils, neurons and fibers. The high level of intensity in OA immunostaining was observed in early developmental stage of oocyte by comparison with low level of OA-ir in late stages of oocyte development. Functionally, OA-injected female shrimps at doses of 2.5×10(-7) and 2.5×10(-6)mol/shrimp, showed significantly decreased gonado-somatic indices, oocyte diameters, and hemolymph vitellogenin levels, compared with control groups. This study showed changes of OA in the CNS and ovary reaching the highest level in early ovarian stages and declining in late stages, and it decreased hemolymph vitellogenin levels, suggesting significant involvement of OA in female reproduction in this species.

Production and characterization of a monoclonal antibody against recombinant cathepsin L1 of Fasciola gigantica

Monoclonal antibodies (MoAbs) against a recombinant cathepsin L1 of Fasciola gigantica (rFgCatL1) were produced in vitro by fusion of BALB/c mice spleen cells immunized with rFgCatL1 and mouse myeloma cells. Reactivity and specificity of these MoAbs were evaluated by indirect ELISA and immunoblotting techniques. Seven MoAb clones were selected from the stable hybridoma clones, namely 1E10, 1F5, 3D11, 4B10, 4D3, 4E3 and 5E7. Clones 1E10, 1F5 and 3D11 were IgM, whereas clones 4B10, 4D3, 4E3 and 5E7 were IgG1. All MoAbs had kappa light chain isotypes. All MoAbs reacted with rCatL1 at molecular weight (MW) 30kDa and with the native CatL1 at MW 27kDa in whole body (WB) extracts of metacercariae (Met), newly excysted juveniles (NEJ), 1, 3, 5-week-old juveniles (Ju), adult WB and adult excretory-secretory (ES) fractions, but not with adult tegumental antigens (TA). All of these MoAbs showed no cross-reactions with antigens of other parasites commonly found in ruminants and human, including Paramphistomum cervi, Eurytrema pancreaticum, Gigantocotyle explanatum, Schistosoma spindale, Schistosoma mansoni, Moniezia benedeni, Avitellina centripunctata, Trichuris sp., Haemonchus placei and Setaria labiato-papillosa. Localization of CatL1 in each developmental stages of F. gigantica by immunoperoxidase technique, using these MoAbs as probes, indicated that CatL1 was present at high concentration in the caecal epithelium and caecal lumen of metacercariae, NEJ, 1, 3, 5-week-old juveniles and adult fluke. This finding indicated that CatL1 is a copiously expressed parasite protein that is released into the ES, thus CatL1 and its MoAb could be a good candidate for immunodiagnosis of fasciolosis in ruminant and human.

Morphology and histology of the adult Paramphistomum gracile Fischoeder, 1901

In the present study, we evaluated the histological morphology of the adult Paramphistomum (P.) gracile. Adult flukes with bodies 5~15 mm in length and 2~7 mm in width were subjected to histological analysis. Longitudinal and transversal serial-sections were stained with hematoxylin and eosin, and examined. The body surface and longitudinal section of P. gracile were also assessed using scanning electron microscopy. In this species, the anterior sucker and posterior sucker (acetabulum) were present on an anterior and posterior part of the body, respectively. The major folds were located in the areas of the anterior sucker, genital canal, and posterior sucker. The fluke membrane was spineless at the tegument surface and in the tegument tissue. Histological data showed structural-systematic characteristics of the digestive tract, reproductive tract, excretory tract, copulatory organs, connective tissues, and muscle tissues. We attempted to elucidate the histological characteristics of P. gracile that might increase the knowledge and understanding of rumen fluke morphology.

Structure of the olfactory receptor organs, their GABAergic neural pathways, and modulation of mating behavior, in the giant freshwater prawn, Macrobrachium rosenbergii

In the giant male prawn, Macrobrachium rosenbergii, the olfactory system is thought to be the main pathway for modulating sexual behavior through pheromone perception. In this report, we first used gross anatomical, histological, and SEM methods to describe the structures of the olfactory receptors (sensilla setae), their neural pathways, and possible role in modulating mating behavior. On the surfaces of antennule and antenna filaments there are four types of sensory receptors, viz single spike-like setae, single flagellum-like setae, multiple flagella-like setae, and aesthetascs (ASs). The ASs, which had previously been proposed to be odor receptor setae, are found only on the short filament of lateral antennule (slAn). Each AS on the slAn connects with olfactory receptor neurons (ORNs), whose axons form an outer central antennule nerve (ocAnNv), which then connects with the olfactory neutrophil (ON) of the brain. Thus, the slAn is the major olfactory organ that conveys sensory inputs from each AS to the ON within the deutocerebrum. GABA immunoreactivity was present in ASs, neurons of ORNs, inner central antennular, lateral tegumentary nerve, ocAnNv and the ON, inferring that GABA is the likely neurotransmitter in modulating olfaction. Disruption of the slAn by ablation or covering with Vaseline, resulted in significant reduction of mating behavior, indicating that this organ is crucial for sex pheromone perception. Identification of the active pheromones and further bioassays are now being performed.

Antigenic components, isolation and partial characterization of excretion-secretion fraction of Paramphistomum cervi

The immunogenic components of adult Paramphistomum cervi excretion-secretion (ES) fraction were revealed by SDS-PAGE and immunoblotting technique using sera from cattle naturally infected with P. cervi, Fasciola gigantica, strongylids, Trichuris sp., and Strongyloides sp. By SDS-PAGE, it was found that the ES fraction comprised 13 distinct protein bands. Immunoblotting analysis of these proteins exhibited nine prominent antigenic bands which were recognized by paramphistomosis antisera. These antigenic proteins had molecular weights ranging from 10-170 kDa. One antigenic protein band of 40 kDa was found to give a consistent reaction with sera from all infected cattle. Its diagnostic sensitivity, specificity and accuracy using this test were 100%, 98.9% and 99.3%, respectively. The positive and negative predictive values were 98% and 100%, respectively. The 40 kDa antigen was partially purified by gel filtration and ion-exchange chromatography. The antigenicity of 40 kDa protein for diagnosis of P. cervi infection was confirmed by immunoblotting and indirect ELISA (at 1:78,125 dilution) using a pool of sera and individual serum samples from infected cattle. The present findings suggest that the 40 kDa protein may be used as a diagnostic antigen for paramphistomosis.

Fischoederius cobboldi: A scanning electron microscopy investigation of surface morphology of adult rumen fluke

Adults Fischoederius cobboldi are conical-shaped, concave ventrally and convex dorsally, measures about 8-10mm in length and 4-6mm in width across the mid section. Scanning electron microscopy (SEM) of entire body showed that the tegumental surface exhibits highly corrugation and transverse folds alternating with grooves and without spines. At higher magnification, the surface of each fold is further increased with a meshwork of ridges separated by irregular-sized pits. The ventral surface has more complex corrugations and invaginations than those of the dorsal surface of the body. Both anterior and posterior suckers have thick edges covered with transverse folds and appear spineless. The genital pore is located at the anterior one-third of the body. There are two types of sensory papillae on the surface: type 1 is bulbous in shape and nipple-like tips, measuring 10-15 μm in diameter at the base, and also type 2 is a similar shape and has short cilia on tips. These sensory papillae occur in large clusters, each having between 7 and 25 units depending on the region of the body. Clusters of papillae on the ventral surface and around the anterior suckers tend to be more abundant and larger in size. The dorsal side of the body exhibit similar surface features, but papillae appear less numerous and are smaller. Corrugations and invaginations of the dorsal aspect are also less extensive than those on the ventral surface of the body.

Distribution and changes of serotonin and dopamine levels in the central nervous system and ovary of the Pacific white shrimp, Litopenaeus vannamei, during ovarian maturation cycle

We investigated changes in serotonin (5-HT) and dopamine (DA) levels and in their distribution patterns in the central nervous system (CNS) and ovary during the ovarian maturation cycle in the Pacific white shrimp, Litopenaeus vannamei. The concentrations of these two neurotransmitters were determined by using high performance liquid chromatography with electrochemical detection. The 5-HT concentration exhibited a gradual increase in the brain and thoracic ganglia during early ovarian stages I, II, and III, reaching a maximum at the mature ovarian stage IV, whereas DA showed its highest concentration at ovarian stage II in the brain and thoracic ganglia and then declined to its lowest concentration at ovarian stage IV. In the ovaries, 5-HT was lowest at ovarian stage I and gradually increased to a peak at ovarian stage IV. Conversely, the concentration of DA was highest at ovarian stages I and II and lowest at ovarian stage IV. In the brain, 5-HT immunoreactivity (-ir) from stage IV and DA-ir from stage II were distributed extensively in neurons of clusters 6, 11, and 17, in fibers, and in the anterior and posterior medial protocerebral, olfactory, antenna II, and tegumentary neuropils. In the circumesophageal, subesophageal, thoracic, and abdominal ganglia, both 5-HT-ir and DA-ir were detected in neuropils and surrounding neurons and fibers. 5-HT-ir and DA-ir were more intense in the thoracic ganglia than in other parts of the CNS. In the ovary, 5-HT-ir exhibited high intensity in late oocytes, whereas DA-ir was more intense in early oocytes. Thus, opposing changes occur in the levels of these two neurotransmitters and in their specific localizations in the CNS and ovary during ovarian maturation, indicating their important involvement in female reproduction.

Paramphistomum cervi: surface topography of the tegument of adult fluke

Adult Paramphistomum cervi or rumen fluke are pear-shaped, slightly concave ventrally and convex dorsally. The worm measures about 5-13 mm in length and 2-5 mm in width across the mid-section. As observed by scanning electron microscopy (SEM), the tegumental surface in all part of the body, appears highly corrugated with transverse folds alternating with grooves and is spineless. At high magnification, the surface of the fold is composed of microfolds or ridges separated by microgrooves or pits. Corrugations and invaginations of the ventral surface are also more extensive than on the dorsal surface of the body. Both anterior and posterior suckers have thick rims covered with transverse folds without spine. The genital pore is situated at the anterior third of the body. There are two types of sensory papillae on the surface: type 1 is bulbous in shape, measuring 10-15 microm in diameter at the base with nipple-like tips, and type 2 has a similar shape and size and also a short cilia on top. These sensory papillae usually occur in large clusters, each having between 5 and 20 units depending on the region of the body. Clusters of papillae on the ventral surface and around the anterior suckers tend to be more numerous and larger in size. The dorsal surface of the body has the least number of papillae.

Paramphistomum cervi: antigenic profile of adults as recognized by infected cattle sera

An antigenic profile of adult Paramphistomum cervi was revealed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting using sera from cattle naturally infected with P. cervi, Fasciola gigantica and strongylids. SDS-PAGE of whole worm extracts exhibited 26 distinct protein bands. Immunoblotting analysis of these proteins showed five major antigenic bands which were recognized by serum of individual cattle naturally infected with P. cervi. These antigenic proteins had molecular weights ranging from 23 to 116kDa. One antigenic protein with a molecular weight of 52kDa exhibited a consistent reaction with sera from all infected cattle. It's diagnostic sensitivity, specificity and accuracy using this test were 100%, 98% and 98.9%, respectively. The positive and negative predictive values were 97.6% and 100%, respectively. This finding suggests that the 52kDa protein may be a diagnostic antigen for paramphistomosis.

Distribution of 28.5 kDa antigen in the tegument of adult Fasciola gigantica

Monoclonal antibody (MoAb) specific to 28.5 kDa tegumental antigen (TA) was used to localize this antigen in various tissues of adult Fasciola gigantica by means of indirect immunofluorescence, immunoperoxidase and immunogold techniques. The indirect immunofluorescence and immunoperoxidase detections revealed that this antigen was concentrated in the tegument particularly in its outer rim, tegumental cells and their processes, epithelial linings of the oral sucker and the proximal part of digestive tract. It was also detected at a moderate concentration in spermatogenic cells in the testes, cells of Mehlis' gland, oocytes within the ovary, and ovum within the egg of adult parasites. At TEM level, the immunogold detection showed deposit of gold particles specifically in G(2) tegumental granules and on the surface membrane. Thus, this antigen is expressed in the tegument and associated structures of adult parasites, and it could be a major component of the G(2) granules which are shown to fuse with the surface membrane and contribute material to replace the casted-off membrane. This process is a part of membrane turnover that prevents the parasite from being attacked by the host immune effector cells.