Damdinsuren Boldbaatar - Academia.edu (original) (raw)

Papers by Damdinsuren Boldbaatar

Mongolian Journal of Agricultural Sciences, Dec 28, 2018

Veterinary Record, 2005

LEPTOSPIROSIS, caused by infection with Leptospira interrogans (sensu lato), is a zoonotic diseas... more LEPTOSPIROSIS, caused by infection with Leptospira interrogans (sensu lato), is a zoonotic disease that affects most species of mammals (Bolin and Zuerner 1995). Horses infected with Leptospira species present with clinical disorders of abortion and recurrent uveitis (Donahue and others 1995, Faber and others 2000). In serological surveillance for leptospirosis carried out by Sebek (1974) in Mongolia, of 123 horses examined from Dornogovi, Dornod, Govi-Altai, Khuvsgul and Uvs provinces, nine were positive at a titre of 1:800 or higher by the microscopic agglutination test (MAT), with antibodies to leptospires of serogroups Sejroe, Grippotyphosa, Pyrogenes, Shermani, Australis and Autumnalis being present. The highest titre, of 1:6400, was found to be against leptospires of serovar Hardjo. The highest prevalence was in Dornogovi province, while the lowest was in Govi-Altai province (Sebek 1974). Vaccination against leptospirosis is not practised in any animal species in Mongolia. The horse is one of the most important domestic animal species in the country, with a total population of 2·4 million (Ministry for Food and Agriculture of Mongolia 2001). Animal husbandry has remained as pastoral in Mongolia, leading to direct and indirect close contacts between animal species sharing the same pasture and water sources. This short communication describes a study to determine the current prevalence of leptospirosis in equine species in Mongolia, in order to provide information for further, largescale surveillance and control programmes. Seventy-two serum samples were randomly collected from horses in the steppe area of Tuv province, which has a horse population of 218,200. There is extensive human and animal movement in this province, whereby animals from different provinces are driven on foot to the slaughterhouse in the capital city, Ulaanbaatar. In order to evaluate the risk factors involved in the transmission and spread of leptospirosis in horses, two further, geographically different provinces were involved in the study. There are no slaughterhouses in either province. Fifty-one serum samples were collected from horses in a dry desert area in Umnugovi province, where a total of 84,700 horses are raised. Another 58 serum samples were taken from Selenge province, which, unlike Umnugovi, has a humid environment. The horse population in Selenge province is 49,000. The serum samples were examined by the MAT in order to detect antibodies to leptospires. The MAT antigen panel consisted of live leptospires of the following serovars (strains): Australis (Akiyami C), Autumnalis (Akiyami A), Ballum (Mus 127), Bataviae (Swart), Bratislava (Jez-Bratislava), Canicola (Hond Utrecht IV), Copenhageni (Shibaura #9), Cynopteri (3522 C),Grippotyphosa (Moskva V),Hardjo (Hardjoprajitno), Hebdomadis (Akiyami B), Icterohaemorrhagiae (RGA), Javanica (Veldrat Bataviae 46), Mangus (TRVL/CAREC/137774), Monjakov (Monjakov), Pyrogenes (Salinem), Ruparupae (M 3), Sentot (Sentot 90 C), Tarassovi (Perepelitsin), Weaveri (CZ Veterinary Record (2005) 157, 518-519

Mongolian Journal of Agricultural Sciences, 2018

Gold-headed tick, Dermacentor nuttalli is widely distributed in Mongolia and an important vector ... more Gold-headed tick, Dermacentor nuttalli is widely distributed in Mongolia and an important vector of transovarially transmitting pathogens to domestic animals. In this study, we describe the morphology of the ovary, as well as the process of the vitellogenesis and ovigenesis on oocytes of the tick, Dermacentor nuttalli. The oocytes were classified into stages that varied from I to V, according to: cytoplasm appearance, presence of the germ vesicle, position, development, presence of yolk granules, accumulation and presence of chorion. To our knowledge, this study is first description on oocytes development stages evaluated by Balashov (1964) of D. nuttalli female and its vitellogenesis. Dermacentor nuttalli хачгийн ооцитын хөгжил Хураангуй: Цус бүрэн сорж, эвцэлдэж хувалзалсан Dermacentor nuttalli эмэгчин хачгийн ооцит, өндөгний хөгжлийг судалснаар хачгийн физиологи, биологийн онцлогийг тогтоох нь шинжлэх ухаан, онол, практикийн өндөр ач холбогдолтой юм. Энэ судалгаагаар D. nuttalli...

Parasitology International, Jun 1, 2019

Given the widespread distribution and medical implication of members of the genus Hymenolepis, sp... more Given the widespread distribution and medical implication of members of the genus Hymenolepis, specific identification of the aetiological agent becomes imperative. For precise diagnosis of the species, molecular techniques such as PCR and RFLP of the nuclear ribosomal internal transcribed spacer 2 (rDNA-ITS2) gene marker were carried out. The results showed distinct restriction patterns for both Hymenolepis nana and Hymenolepis diminuta when digested with either of the enzymes RsaI, HaeIII or HhaI. The annotated rDNA-ITS2 sequences from the two species revealed differences in the length; the folded secondary structure also depicted clear demarcation between the two species with variations in length of the helices, pyrimidine-pyrimidine mismatches and sites where motifs occur. In phylogenetic analysis of the evolutionary relationship between the two species as well as with other members of the family Hymenolepididae, the species causing human hymenolepiasis were found to be distantly related as they diverged independently from the ancestral lineage.

Insect Biochemistry and Molecular Biology, Sep 1, 2007

Ticks are obligate hematophagous ectoparasites with a life cycle characterized by a period of sta... more Ticks are obligate hematophagous ectoparasites with a life cycle characterized by a period of starvation; many ticks spend more than 95% of their life off the host. Autophagy, which is the process of bulk cytoplasmic degradation in eukaryotic cells, is induced by starvation and is essential for extension of the lifespan. Therefore, we hypothesized that autophagy also occurs in ticks; however, there has been no report on autophagy-related (ATG) genes in ticks. Here, we show the homologue of an ATG gene, ATG12, and its expression pattern from the nympal to adult stages in the three-host tick Haemaphysalis longicornis. The sequence analysis showed that H. longicornis ATG12 (HlATG12) cDNA is 649 bp, has a 411 bp ORF coding for a 136-amino acid polypeptide with the carboxy-terminal glycine residue, and has a predicted molecular mass of 15:2 kDa. Moreover, RT-PCR revealed that HlATG12 was downregulated at the beginning of feeding, upregulated after engorgement, and downregulated again after molting. The expression level of HlATG12 was highest at 3 months after engorgement. By immuno-electron microscopy, it was demonstrated that HlAtg12 was localized to the region around granule-like structures within midgut cells of unfed adults. In conclusion, HlATG12 might function during unfed and molting stages.

Parasitology Research, May 3, 2011

Autophagy is the intracellular protein degradation process which is induced by starvation. Ticks ... more Autophagy is the intracellular protein degradation process which is induced by starvation. Ticks have a unique tolerance for starvation, and it is possible that this tolerance is associated with their longevity. Previously, we isolated the homologues of four autophagy-related (ATG) genes in the hard tick, Haemaphysalis longicornis, suggesting that autophagy appeared to play an important role in tolerance for starvation as well as the development of ticks. In this study, the homologue of ATG6 was isolated from H. longicornis (HlATG6). HlATG6 mRNA expression was higher in the egg and unfed larval stages than in other stages and upregulated in ovaries during the blood-feeding period. Moreover, HlATG6-knockdowned ticks laid a few and poorly developed eggs that were white brown in color and not well surface-coated with wax. However, the expression of vitellogenin (Vg)-2, HlVg-2, in the fat body of HlATG6-knockdowned ticks was significantly upregulated. In addition, hemolymph had a deep brown color in HlATG6-knockdowned ticks on day 21 after engorgement and drop-off, indicating that the Vgs synthesized by the fat body and midgut are retained and accumulated in the hemolymph of HlATG6-knockdowned ticks, probably due to the downregulation of the Vg uptake capability of oocytes. Interestingly, HlATG6 knockdown provided non-significant influences on the expression of the Vg receptor (HlVgR) at oocytes, suggesting a non-significant depression of VgR-mediated endocytosis in the oocytes of HlATG6-knockdowned ticks. Therefore, it was interpreted that the repression of Vg uptake in the oocytes of HlATG6-knockdowned ticks may be involved in endocytic processes other than the receptor recognition of Vgs in oocytes.

Insect Biochemistry and Molecular Biology, Mar 1, 2008

Three protein disulfide isomerases from Haemaphysalis longicornis ticks (designated as HlPDI-1, H... more Three protein disulfide isomerases from Haemaphysalis longicornis ticks (designated as HlPDI-1, HlPDI-2, and HlPDI-3) were previously identified. In order to further analyze their biological functions, the dsRNA of each HlPDI gene and one dsRNA combination of HlPDI-1/HlPDI-3 were separately injected into female ticks. Reduction of gene and protein expression of HlPDIs by RNA interference (RNAi) was demonstrated by real-time PCR, RT-PCR and Western blot analysis. In single dsRNA-injected groups, HlPDI-1 RNAi impacted tick blood feeding and oviposition, HlPDI-2 RNAi impacted tick viability and HlPDI-3 RNAi had no significant impact by itself. However, the injection of a combination of HlPDI-1/HlPDI-3 dsRNA had synergistic effects on tick viability. Furthermore, the midgut and cuticle were severely damaged in HlPDI-2 dsRNA-injected ticks and HlPDI-1/HlPDI-3 dsRNA-injected ticks, respectively, and disruption of HlPDI genes led to a significant reduction of disulfide bond-containing vitellogenin (Vg) expression in ticks. These results indicate that PDIs from H. longicornis are involved in blood feeding, viability and oocyte development, probably by mediating the formation of disulfide bond-containing proteins of the ticks and the formation of basement membrane and cuticle components such as extracellular matrix (ECM). This is the first report on the functional analysis of PDI family molecules as well as the interactions of PDI and other molecules in blood-feeding arthropods.

Insect Biochemistry and Molecular Biology, Mar 1, 2012

Ticks grow rapidly during blood feeding, and their body weight may ultimately increase 100-fold m... more Ticks grow rapidly during blood feeding, and their body weight may ultimately increase 100-fold more than that before feeding. The molecular mechanisms controlling growth during blood feeding in ticks remain largely unknown. The conserved insulin/PI3K/Akt signaling pathway regulates growth and metabolism in eukaryotes. Here, we show evidence for the involvement of Akt in growth during blood feeding in the parthenogenetic strain of the hard tick Haemaphysalis longicornis. We identified a homolog of the Ser/Thr kinase Akt (HlAkt) from the EST database of the H. longicornis embryo. HlAkt cDNA had a 1,590 bp ORF that encodes 529 amino acids with a predicted molecular weight of 60 kDa. HlAkt possesses a PH domain, a Ser/Thr kinase domain, a hydrophobic motif, and dual phosphorylation residues (Thr 338 and Ser 503) that are essential for kinase activation. Knockdown of HlAkt by RNA interference caused inhibition of blood feeding in female ticks. Histological observation demonstrated that HlAkt knockdown led to the arrest of growth in internal organs. HlAkt knockdown also affected the expressions of blood meal-induced genes that are essential for blood digestion, development, and reproduction in the female tick. These results strongly indicate that HlAkt is essential to complete the blood feeding process accompanied by the growth of internal organs in adult ticks. This is the first report of identification and characterization of Akt in Chelicerata, including ticks.

Journal of Insect Physiology, Nov 1, 2010

Ovarian development and egg maturation are crucial processes for the success of reproduction in t... more Ovarian development and egg maturation are crucial processes for the success of reproduction in ticks. Three full-length cDNAs encoding the precursor of major yolk protein, vitellogenin, were obtained from cDNA libraries of the Haemaphysalis longicornis tick and designated as HlVg-1, HlVg-2 and HlVg-3. The HlVg mRNAs were found in fed females with major expression sites in the midgut, fat body and ovary. Native PAGE and Western blot demonstrated that HlVgs in the hemolymph, fat body and ovary of fed females consisted of four major polypeptides. RNAi results showed that HlVg dsRNA-injected ticks obtained lower body weight, egg weight and showed higher mortality of engorged females after blood sucking than control groups. Our results indicate that all HlVgs are essential for egg development and oviposition.

Parasitology Research, Sep 25, 2010

Scavenger receptors (SRs) are cell-surface proteins and exhibit distinctive ligand-binding proper... more Scavenger receptors (SRs) are cell-surface proteins and exhibit distinctive ligand-binding properties, recognizing a wide range of ligands that include microbial surface constituents and intact microbes. The class B scavenger receptor CD36 (SRB) is predominantly expressed by macrophages and is considered important in innate immunity. We here show the identification and characterization of SRB from the hard ixodid tick, Haemaphysalis longicornis (HlSRB). The full-length cDNA was 2,908 bp, including an ORF encoding of 1,518 amino acids with a pI value of 5.83. H. longicornis SRB contains a hydrophobic SRB domain and four centrally clustered cysteine residues for arrangement of disulfide bridges. Deduced amino acid sequence has an identity of 30-38% with the SRB of other organisms. RT-PCR analysis showed that mRNA transcripts were expressed in multiple organs of adult ticks but with a different transcript level in the developmental stages of H. longicornis ticks. His-tagged recombinant HlSRB was expressed in Escherichia coli with an expected molecular mass of 50 kDa. In Western blot analysis, mouse anti-rHlSRB serum recognized a strong reaction with a 50 kDa protein band in lysates prepared from egg and adult tick but showed a weak reaction with lysates of larva and nymph. In an indirect immunofluorescent antibody test, HlSRB antiserum recognized the protein located on the midgut, salivary glands, and ovary of partially fed H. longicornis females. Silencing of the HlSRB gene by RNAi led to a significant reduction in the engorged female body weight. It is noteworthy that more than a dozen SRB orthologs have been identified in the genomes of insect species with functions related to pheromone signaling, innate immunity, phagocytic clearance of apoptotic cells, and various aspects of the fatty acid metabolism. This is the first report of the identification and characterization of the SRB homologue in Chelicerata, including ticks, horseshoe crabs, scorpions, spiders, and mites.

Parasitology Research, May 23, 2012

4E-BP, an eIF4E-binding protein, is well known as a cap-dependent translation inhibitor. Here, th... more 4E-BP, an eIF4E-binding protein, is well known as a cap-dependent translation inhibitor. Here, the 4E-BP homolog, Hl4E-BP, was isolated and identified from the hard tick Haemaphysalis longicornis. Hl4E-BP transcripts were ubiquitously expressed in the active stages, including the larvae, nymphs, and female adults, and the transcription levels were found to be higher in unfed than engorged ticks. In contrast, the expression levels of non-phosphorylated Hl4E-BP, which is a 13.4-kDa protein detected by the antirecombinant Hl4E-BP antibody, were the highest in engorged ticks and significantly decreased progressively during the unfed starvation period of ticks. The functional role of Hl4E-BP as a metabolic brake was verified by histochemical observations on the lipid storage in midguts and fat bodies during the starvation period using ticks injected with dsHl4E-BP. The results indicate that Hl4E-BP is highly relevant to the lipid storage of ticks during the non-feeding starvation period. Our results suggest, for the first time, that Hl4E-BP may have a crucial role in the starvation resistance of ticks in an off-host condition via lipid metabolism control, although it was unclear whether Hl4E-BP might be involved in lipid synthesis regulation and/or lipid consumption inhibition.

Insect Biochemistry and Molecular Biology, 2006

ABSTRACT

BMC Research Notes

Objectives Haemaphysalis longicornis is the most important tick species in Japan and has a wide r... more Objectives Haemaphysalis longicornis is the most important tick species in Japan and has a wide range of vector capacity. Due to its veterinary and medical importance, this tick species has been used as a model for tick/vector biological studies. To identify the key molecules associated with physiological processes during blood feeding and embryogenesis, full-length cDNA libraries were constructed using the fat body, hemocytes-containing hemolymph, midgut, ovary and salivary glands of fed females and embryos of the laboratory colony of parthenogenetic H. longicornis. The sequences of cDNA from the salivary glands had been already released. However, the related information is still poor, and the other expressed sequence tags have not yet been deposited. Data description A total of 39,113 expressed sequence tags were obtained and deposited at the DNA DataBank of Japan. There were 7745 sequences from embryos, 7385 from the fat body, 8303 from the hemolymph including hemocytes, 7385 fro...