• Journal of Microbiology and Biotechnology
• /
• v.30 no.5
• /
• pp.642-648
• /
• 2020

In this study, we investigated the effects of linoleic acid (LA) treatment on Brucella abortus infection in professional phagocyte RAW264.7 cells, particularly during the pathogen's invasion and intracellular growth in these cells, as well as in murine model BALB/c mice focusing on bacterial splenic proliferation and immunoregulatory activities. LA inhibited the growth of Brucella in a dose- and time-dependent manner. The ability of the pathogen to enter the phagocytes was inhibited as was its survival within these cells. This was accompanied by increased nitrite accumulation in these cells at 24 h post-infection. The concentration of LA used in the present study did not affect the total body weight or liver function of the mice. During Brucella infection, the total splenic weight of these animals was not changed; rather, resistance to bacterial proliferation was enhanced in the spleen. Furthermore, mice treated with LA displayed elevated levels of IL-12 and IFN-γ but reduced levels of IL-10 during infection. The findings in this study showed the regulatory role of LA against B. abortus infection suggesting its potential use in designing intervention strategy for brucellosis.

• Korean Journal of Veterinary Research
• /
• v.35 no.1
• /
• pp.143-148
• /
• 1995

Brucella abortus cell wall antigen was extracted from Brucella abortus 1119-3 by ultrasonication and followed by sodium dodecyl sulfate(SDS) treatment. In order to confirm whether this preparation is serologically cross reactive with Yersinia enterocolitica 0:9, Western blot analysis with mouse anit-Brucella abortus1119-3 and with mouse anti-Yersinia enterocolitica 0:9 was performed. ELISA results from using those Brucella antigen and Yersinia antigen were assessed whether they had correlation. According to the results of western blot analysis and ELISA, there was no evidence of cross reactivity between the Brucella abortus 1119-3 antigen preparation and Yersinia enterocolitica 0:9. Therefore the SDS treated antigen prepared in this study could be suitably used as specific ELISA antigen without confusion in the interpretation of serological tests for brucellosis in cattle.

• Korean Journal of Veterinary Service
• /
• v.33 no.1
• /
• pp.29-35
• /
• 2010

This study was performed to test the hypothesis that Brucella abortus strain RB51 (SRB51) might protect Korean indigenous mongrel dog against challenge with either virulent B. abortus biotype 1 or B. canis. A total of 12 Korean mongrel dogs were divided into four groups (Group A, B, C and D). Dogs belonging to Group A and C were inoculated subcutaneously with $1{\times}10^9$ CFU of SRB51 in 1ml of sterile phosphate buffered saline (PBS). Dogs of Group B and D were inoculated subcutaneously with 1ml of sterile PBS as control. At 12 weeks post vaccination, dogs of Group A and B were challenged by oral inoculation of virulent strain of B. canis ($5.0{\times}10^9$ CFU) and dogs of Group C and D were challenged by oral inoculation of virulent strain of B. abortus biotype 1 ($4.4{\times}10^{10}$ CFU). The serum antibodies titers in all dogs were monitored at regular interval for eight weeks after challenge (AC) by standard tube agglutination test, plate agglutination test, rose bengal test, 2-mercaptoethanol rapid slide agglutination test and 2-mercaptoethanol tube agglutination test. No antibody titers in Group A and C was detected. Also, the challenge strains were not found from blood of all dogs of Group A and C from 1 week AC till the end of the experiment by culture and modified AMOS-PCR, whereas B. canis and B. abortus challenge strains were detected from blood of Group B and D, respectively. In addition, neither of two challenge bacteria was recovered from liver, spleen, kidneys, lymph nodes and reproductive tracts of Group A and C dogs after postmortem. However, B. canis and B. abortus challenge strains were isolated from these tissues of Group B and D, respectively. These data suggest that SRB51 could be a promising vaccine candidate for immunizing dogs to control canine brucellosis caused by B. canis or B. abortus.

• Korean Journal of Veterinary Service
• /
• v.33 no.2
• /
• pp.151-156
• /
• 2010

This survey was carried out to investigate the seroprevalence of antibodies to Neospora caninum in Korean indigenous cattle that was raised in central area province Gyeongnam, Korea. A total of 719 sera were tested for N. caninum antibodies using ELISA (Herdcheck anti-Neospora, IDEXX Laboratories Inc., Westbrook, Maine USA). Seroprevalence of individual and farm were 29.8%(214/719) and 53.2%(50/94). Regional seropositive rates of the samples were 61%(47/77), 23.3%(7/30), 13.8%(49/355), 37.6%(77/205), 65.4%(34/52) at Changwon, Jinhae, Gimhae, Miryang, Yangsan, respectively. It showed difference at the age and on the herd size of farms. A herd of cattle above the age of 5 was more infective than under 4 years. And in seroprevalence by herd size farms having under 30 heads was top(35.7%). Seropositive 214 herds of N. caninum antibidies were tested for brucellosis by test tube. Positive rate of double infection was 16.4%(35/214).

• Korean Journal of Veterinary Service
• /
• v.37 no.4
• /
• pp.297-305
• /
• 2014

Animals and disease frequency of the rescued dogs were investigated in Incheon Veterinary Medical Association Animal Shelter from January in 2012 to December in 2013. Three zoonoses (rabies, brucellosis, and dirofilariosis) and three infectious diseases (canine distemper, canine parvoviral enteritis, and canine influenza) were examined for stray dogs. Among 5,603 heads, 647 (11.5%) went back to their owner and 969 (17.3%) were adopted to new families. Prevalence of dirofilariosis, canine distemper and canine parvoviral enteritis were 2.2% (16/718), 6.0% (24/399) and 6.1% (24/396), respectively. Positive antibody rates against rabies, B. canis and canine influenza virus were 20.5% (41/200), 0.1% (1/718) and 2.0% (4/200), respectively. Protective antibody for canine distemper virus and canine parvovirus were shown in 47.0% (94/200). The data indicate that control measures including facility standards and disease control program are one of the important aspects of the shelter management because stray dogs are exposed to various infectious agents.

• Molecules and Cells
• /
• v.44 no.7
• /
• pp.517-528
• /
• 2021

A recent genetic study with Brucella abortus revealed the secretion activator gene A (SagA) as an autolysin component creating pores in the peptidoglycan (PGN) layer for the type IV secretion system (T4SS) and peptidoglycan hydrolase inhibitor A (PhiA) as an inhibitor of SagA. In this study, we determined the crystal structures of both SagA and PhiA. Notably, the SagA structure contained a PGN fragment in a space between the N- and C-terminal domains, showing the substrate-dependent hinge motion of the domains. The purified SagA fully hydrolyzed the meso-diaminopimelic acid (DAP)-type PGN, showing a higher activity than hen egg-white lysozyme. The PhiA protein exhibiting tetrameric assembly failed to inhibit SagA activity in our experiments. Our findings provide implications for the molecular basis of the SagA-PhiA system of B. abortus. The development of inhibitors of SagA would further contribute to controlling brucellosis by attenuating the function of T4SS, the major virulence factor of Brucella.

• Journal of Microbiology and Biotechnology
• /
• v.32 no.1
• /
• pp.6-14
• /
• 2022

Brucella spp. are facultative intracellular pathogens that invade, survive and proliferate in numerous phagocytic and non-phagocytic cell types, thereby leading to human and animal brucellosis. Outer membrane proteins (Omps) are major immunogenic and protective antigens that are implicated in Brucella virulence. A strain deleted of the omp16 gene has not been obtained which suggests that the Omp16 protein is vital for Brucella survival. Nevertheless, we previously constructed an omp16 conditional deletion strain of Brucella, ∆Omp16. Here, the virulence and immune response elicted by this strain were assessed in a mouse model of infection. Splenomegaly was significantly reduced at two weeks post-infection in ∆Omp16-infected mice compared to infection with the parental strain. The bacterial load in the spleen also was significantly decreased at this post-infection time point in ∆Omp16-infected mice. Histopathological changes in the spleen were observed via hematoxylin-eosin staining and microscopic examination which showed that infection with the ∆Omp16 strain alleviated spleen histopathological alterations compared to mice infected with the parental strain. Moreover, the levels of humoral and cellular immunity were similar in both ∆Omp16-infected mice and parental strain-infected mice. The results overall show that the virulence of ∆Omp16 is attenuated markedly, but that the immune responses mediated by the deletion and parental strains in mice are indistinguishable. The data provide important insights that illuminate the pathogenic strategies adopted by Brucella.

• Journal of Microbiology and Biotechnology
• /
• v.33 no.4
• /
• pp.441-448
• /
• 2023

Brucellosis is a contagious zoonotic disease that infects millions of people annually with hundreds of millions more being exposed. It is caused by Brucella, a highly infectious bacterial species capable of infecting humans with an estimated dose of 10-100 organisms. Sirtuin 1 (SIRT1) has been reported to contribute to prevention of viral diseases as well as a chronic infection caused by Mycobacterium bovis. Here, we investigated the role of SIRT1 in the establishment of Brucella abortus infection in both in vitro and in vivo systems using the reported SIRT1 activators resveratrol (RES), piceatannol (PIC), and ginsenoside Rg3 (Rg3). In RAW264.7 cells, SIRT1 activators did not alter the adherence of Brucella or Salmonella Typhimurium. However, reduced uptake of Brucella was observed in cells treated with PIC and Rg3, and survival of Brucella within the cells was only observed to decrease in cells that were treated with Rg3, while PIC treatment reduced the intracellular survival of Salmonella. SIRT1 treatment in mice via oral route resulted in augmented Brucella resistance for PIC and Rg3, but not RES. PIC treatment favors Th2 immune response despite reduced serum pro-inflammatory cytokine production, while Rg3-treated mice displayed high IL-12 and IFN-γ serum production. Overall, our findings encourage further investigation into the complete mechanisms of action of the different SIRT1 activators used as well as their potential benefit as an effective alternative approach against intracellular and extracellular pathogens.

• Journal of Preventive Veterinary Medicine
• /
• v.43 no.4
• /
• pp.214-220
• /
• 2019

Although canine brucellosis has been known to be an important re-emerging zoonosis, the pathophysiological mechanisms of Brucella canis infection remains clues to be solved. Different culture models, single and co-culture models, were constructed with canine epithelial cells, D17 and macrophage, DH82 to investigate the induction of immune responses in in vivo B. canis infection. Expression of genes related with induction of immune responses, Th1, Th2 and Th17, was compared in the two different models after the bacterial infection. In this study, expression of cytokine genes, IL-1β, IL-5, IL-6, IL-10, IL-23, and TNF-α was quantified in the DH82 at different time points using RT-qPCR in the two different culture systems after the infection. Cytokine genes related with Th1, IL-1β and TNF-α and Th17, IL-6 and IL-23 were expressed with time-dependent manners in the both systems (p<0.05). However, increase of Th2-related cytokine genes expression was not detectable in the both systems by comparison with control. The expression of Th1 and Th17 related cytokine genes was earlier in single cell culture than those in co-culture model (p<0.05). In general, amounts of the expressed genes were shown higher in single cell model than those in co-culture models. This study indicate that Th1 and Th17-associated immune responses are central to B. canis infection in dogs. In addition, it suggests a specific role of epithelial cells in the B. canis infection in vivo, which should resolved in the further study.

• Journal of Microbiology and Biotechnology
• /
• v.33 no.8
• /
• pp.1006-1012
• /
• 2023

In this study, we investigated the effects of sodium propionate (SP) treatment on intracellular mechanism of murine macrophages and its contribution to host immunity during Brucella abortus 544 infection. The intracellular growth assay revealed that SP inhibited Brucella replication inside the macrophages. To determine intracellular signaling involved during SP treatment after Brucella infection, we analyzed the change of five different cytokines production relevant to SP such as TNF-α, IL-10, IFN-γ, IL-1β, and IL-6, and the results indicated that the boost with IL-10 was apparent throughout the culture period for 48 h as well as IL-1β which was apparent at 24 h post-infection and IFN-γ which was apparent at 24 h and 48 h in comparison to SP untreated groups. On the other way, SP-treated cells displayed suppressed production of TNF-α and IL-6 at all time points tested and 48 h post-infection, respectively. Furthermore, we conducted western blot to establish a cellular mechanism, and the result suggested that SP treatment attenuated p50 phosphorylation, part of the NF-κB pathway. These findings indicated that the inhibitory effect of SP against Brucella infection could be attributed through induction of cytokine production and interference on intracellular pathway, suggesting SP as a potential candidate for treating brucellosis.