• The Plant Pathology Journal
• /
• v.22 no.4
• /
• pp.329-333
• /
• 2006

Two distinct and stable isolates of Barley mild mosaic virus(BaMMV) designated as Naju82-S(severe) and Naju82-M(mild) were obtained. These two isolates differed in their symptomatology, virus transmission characteristics and cultivar specificity at various temperature. Thus, these isolates were referred to as strains in this study. BaMMV Naju-S strain showed severe mosaic symptoms accompanied by necrosis on the infected leaves. Naju82-S strain is more virulent demonstrated by shorter incubation period and relatively high virus concentration than Naju82-M strain. Five Korean cultivars were tested for their pathogenicity to different strains based on the rate of infection. Results showed that infection rate of cultivars to both strains did not significantly differed from each other. However, under different temperatures, the pathogenicity on the two cultivars such as cultivars Hopumbori and Sessalbori were significantly affected. Hopumbori was moderately resistant to both strains at $10-12^{\circ}C$ and susceptible at $15-18^{\circ}C$. Similarly, Sessalbori was moderately resistant at $10-12^{\circ}C$ to both strains but distinctly differentiated at $15-18^{\circ}C$ wherein it was resistant to mild strain and highly susceptible to severe strain. Other cultivars including Baegdong, Jinyangbori and Neahanssalbori consistently showed susceptible reaction to both strains at varying temperatures tested in this study.

• Journal of Microbiology and Biotechnology
• /
• v.14 no.4
• /
• pp.822-828
• /
• 2004

Nopaline-type Agrobacterium tumefaciens strain C58 cannot utilize octopine (Oct) as the sole carbon and nitrogen sources. This strain harbors two plasmids; a virulent plasmid, pTiC58, and a megaplasmid, pAtC58. From strain NT1, which is a derivative of C58 harboring only pAtC58, we isolated spontaneous mutants that utilize Oct as the sole nitrogen source. These Oct-catabolizing mutants, however, could not utilize the opine as the sole carbon source. In contrast, strain UIA5, a plasmid-free derivative of C58, could not give rise to such mutants. The mutations isolated from NT1 were mapped to socR in pAtC58, which is a negative regulator of the soc operon responsible for the uptake and catabolism of an Amadori opine, deoxyfructosyl glutamine (Dfg). A derivative of UIA5 carrying a clone of the soc operon with a transposon inserted in socR also utilizes Oct as the sole nitrogen source. However, UIA5 harboring the operon with mutations in each of the structural genes in the soc operon, socA, B, C, and D, lost the ability to generate spontaneous Oct-utilizing mutants, suggesting that soc genes in pAtC58 are required for the utilization of Oct as a nitrogen source, and that derepressed expression of these genes allows cells to utilize Oct. In contrast, Oct-catabolizing mutants derived from C58, which grew using Oct as the sole nitrogen source, could also utilize the opine as the sole carbon source. These mutants did not carry any detectable mutations in socR or the region upstream to the gene in pAtC58, suggesting that mutations occurring elsewhere in the genome, most likely in pTiC58, allow the uptake and catabolism of the opine.

• Korean Journal of Veterinary Research
• /
• v.46 no.3
• /
• pp.235-248
• /
• 2006

The VP2 full gene of Korean infectious bursal disease virus(IBDV) strain, SH/92, three attenuated vaccine strains, Bur706, Bursine-2 and CEV/AC strains, were amplified by reverse transcriptase-polymerase chain reaction and sequenced and compared with published VP2 gene sequences of IBDVs. The VP2 nucleotide sequence similarity between SH/92 and three vaccine stains was 95.6~96.5% whereas the nucleic acid similarity among three vaccine strains was 97.5~98.5%. The amino acid sequence similarity of VP2 of SH/92 compared with three vaccine strains was between 94.4 and 97.6% while the amino acid similarity among three vaccine strains was between 97.4 and 98.4%. The amino acid similarity between SH/92 and classical virulent strain, 52/70 and STC strain was 96.4 and 96.5%, respectively. The serine-rich heptapeptide was conserved in CEVAC and Bursine-2 as well as SH/92 but not in Bur706. The phylogenetic tree developed from amino acid sequences showed that SH/92 was categorized with vv IBDVs(HK46, OKYM, KKI, UPM94/273, SH95) in one branch while three vaccine strains were catagorized with STC strain in the other branch.

• Parasites, Hosts and Diseases
• /
• v.31 no.4
• /
• pp.363-370
• /
• 1993

This study was performed to evaluate the prophylactic effects of trimethoprim- sulfamethoxazole (TMP-SMZ) In mice experimentally infected with virulent RH strain and avirulent Beverley strain of T dognii. The mice infected with $1{\times}10^5$ tachyzoltes were used In the measurement of mean survival days, and the mice infected with 10 cysts were used In the tltratlons of specific antibodies and enumeration of brawn cysts. Mean survival days of mice were significantly increased In mice treated with TMP-SMZ as compared with splramycln-treated and untreated control group. Mean survival days and survival rates of mice were Increased according to the Increment of dosages, and TMP-SMZ protected 100% of mice after fifteen daily dose of 24 mg/mouse or more admlnlsted orally. Toxoplasma-specific serum IgG and IgM antibody titers were slgnlflcantly lower in mice treated with TMP-SMZ than those of splramycln-treated and untreated control group. Toxoplosma cysts were not found In mice treated with TMP-SMZ at a dose of 24 mg/mouse or more per day but the group of splramycin treatment and untreated controls were found in the brain from 20 days after Infection. The present results revealed that TMP-SMZ can be used as a prophylactic agent against murine toxoplasmosls after Intraperitoneally challenges with the virulent or avlrulent strain of T. gondii.

• Parasites, Hosts and Diseases
• /
• v.33 no.3
• /
• pp.201-210
• /
• 1995

This study aims to assess the possible strain-dependent variations in detection of ToxopLosmn antigens and antibodies. The virulent RH strain or avirulent Beverley strain of T gondii were injected into mice, intraperitoneally, and their antigens, antibodies and parasites were identified from the blood or tissues: liver, brain and spleen by ELISA, Western blot and PCR. In mice infected with RH strain, circulating antigens and parasitemia were first detected from 2 days after infection, and ToxopIasma DNA were found in the blood, liver, brain and spleen from 3 days after infection. It was impossible to detect specific IgM and IgG antibodies to T gondij and any specific band was not found by Western blot. In mice infected with Beverley strain, circulating antigens were detected between day 10 and day 35. The Toxoplusma DNA was found in the blood and liver from day 15 until day 60, and in the brain from day 20. But Toxoplosma DNA in the spleen were mainly detected between day 10 and day 30. The IgM antibodies were first appeared on day 10 post-infection, and were noted obviously increased between day 15 and 25. The IgG antibodies were first detected on day 15, and showed progressively increased titers. The antibody binding bands were specific according to infection period. Sera from mice infected with Beverley strain reacted mainly with the antigen of 27.5-kDa and 32.5-kDa. In conclusion, mice infected with RH strain revealed Toxoplosma antigens strongly, but not antibodies. However. mice infected with Beverley strain revealed both the Toxoplasma antigens and antibodies. The present results showed that immune responses are different between avirulent and virulent T gonnii.

• Korean Journal of Veterinary Research
• /
• v.12 no.1
• /
• pp.71-75
• /
• 1972

Due to the fact that an inactivated anthrax vaccine may show no or lower immunogenicity and stability, a number of spore vaccines were exclusively used worldwide. In these studies non or less allergic strain of anthrax bacillus was selected and made a capsulated vegetative organisms. Anthrax organisms of a virulent strain were cultivated on sodium bicarbonate medium with or without adding I-alanine in which B. anthracis grew luxuriantly without forming spores. Inactivation of the organisims was carried out at $37^{\circ}C$ water bath for 3 days after the bacterial culture was mixed with formalin in a final concentration of two per cent. Aluminum hydroxide gel was added to the mixture of anthrax and blackleg bacterin. Guinea pigs were injected with the vaccine via subcutaneous or intramuscular route and challenged after three weeks, and the possibilities of protection was tested. Throughout the studies, the vaccines possibly protected the vaccinated guinea pigs more than 80 per cent compared to that of the controls. This experimental results strongly suggest that the vaccine may possibly applicable to the prevention of bovine anthrax and blackleg.

• Journal of Microbiology and Biotechnology
• /
• v.25 no.10
• /
• pp.1614-1620
• /
• 2015

Plasmid-cured derivative strains of Bacillus anthracis are frequently used in laboratory studies. Plasmid incompatibility, which does not increase the risk of chromosomal mutation, is a useful method for plasmid curing. However, in bacteria containing multiple plasmids, it often requires the sequential introduction of multiple, specific incompatibility plasmids. This lengthy process renders the traditional plasmid incompatibility method inefficient and mutation-prone. In this study, we successfully cured plasmids pXO1 and pXO2 from B. anthracis A16 simultaneously using only one recombinant incompatible plasmid, pKORT, to obtain a plasmid-free strain, designated A16DD. This method may also be useful for the simultaneous, one-step curing of multiple plasmids from other bacteria, including Bacillus thuringiensis and Yersinia pestis.

• Asian-Australasian Journal of Animal Sciences
• /
• v.9 no.2
• /
• pp.231-235
• /
• 1996

Bangladeshi indigenous chickens of mixed ages vaccinated twice at a three week interval with either conventional vaccines-$F_1$ (ocular) and M (mukteswar, Intramuscular), or heat resistant $V_4$ vaccine administered by either the ocular or oral routes, all showed satisfactory hemagglutination inhibition antibody (HI) responses and protection against Newcastle Disease (NCD) challenge persisting for four months. The antibody response to $F_1$ and M was higher than for $V_4$, which was similar whether administered by the ocular or oral routes. All vaccinated treatments have a significant level of protection compare to the control group (p<0.01). No significant difference (p>0.05) in the protection against controlled challenge with virulent NCD virus was found between vaccinated groups.

• Korean Journal of Veterinary Research
• /
• v.49 no.2
• /
• pp.127-133
• /
• 2009

Salmonella enterica subsp. enterica serovar gallinarum (S. gallinarum) is the agent of fowl typhoid, and the 9R vaccine is a commercial live vaccine for the prevention of fowl typhoid. The aim of this study was to assess the safety and immunogenicity of different brands of S. gallinarum 9R vaccine used in commercial laying chickens in Korea. All 9R strains originated from three different brands showed the same pattern in the biochemical and serological properties, and pulsed field gel electrophoresis (PFGE) profile. But, there was a difference in rhamnose fermentaion, agglutination with Salmonella group $D_1$ antiserum and PFGE pattern between 9R vaccine strain and field S. gallinarum isolates. In laboratory and field trials for assesment of safety and immunogenicity of 9R vaccine, all of the three 9R vaccines showed the same safety in commercial laying chickens. In addition, there was a significant difference between the vaccinated and unvaccinated control groups in mortality and the re-isolation rate of the challenge strain from the tissues (p < 0.05), and no difference by the brands of 9R vaccine. The results from this study indicated that all three different brands of S. gallinarum 9R vaccine showed highly protection against mortality and organ invasion in commercial laying chickens exposed to virulent strains of S. gallinarum.

• The Plant Pathology Journal
• /
• v.38 no.2
• /
• pp.102-114
• /
• 2022

Pectobacterium carotovorum subsp. carotovorum (Pcc) is a gram-negative, broad host range bacterial pathogen which causes soft rot disease in potatoes as well as other vegetables worldwide. While Pectobacterium infection relies on the production of major cell wall degrading enzymes, other virulence factors and the mechanism of genetic adaptation of this pathogen is not yet clear. In the present study, we have performed an in-depth genome-wide characterization of Pcc strain ICMP5702 isolated from potato and compared it with other pathogenic bacteria from the Pectobacterium genus to identify key virulent determinants. The draft genome of Pcc ICMP5702 contains 4,774,457 bp with a G + C content of 51.90% and 4,520 open reading frames. Genome annotation revealed prominent genes encoding key virulence factors such as plant cell wall degrading enzymes, flagella-based motility, phage proteins, cell membrane structures, and secretion systems. Whereas, a majority of determinants were conserved among the Pectobacterium strains, few notable genes encoding AvrE-family type III secretion system effectors, pectate lyase and metalloprotease in addition to the CRISPR-Cas based adaptive immune system were uniquely represented. Overall, the information generated through this study will contribute to decipher the mechanism of infection and adaptive immunity in Pcc.