• Journal of Korean Academy of Oral Health
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• v.43 no.3
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• pp.118-123
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• 2019

Objectives: The purpose of this study was to investigate changes in the composition of artificial cariogenic biofilms using a Streptococcus mutans biofilm model over a period of time. Methods: We analyzed the dry weight, colony forming unit (CFU) number, extracellular polysaccharide (EPS) biovolume, and acid production rate of S. mutans biofilms formed on saliva-coated hydroxyapatite discs after 26 h, 50 h, 74 h, 98 h, 171 h, and 195 h. In addition, we performed a laser scanning confocal fluorescence microscopy to determine the bacterial volume, EPS biovolume, and biofilm thickness. We calculated the biofilm density using dry weight and EPS biovolume. Results: Over a period of time, there was no change in the CFU number and acid production rate of S. mutans biofilms, but there was an increase in the dry weight and EPS biovolume of S. mutans biofilms. The bacterial volume, EPS biovolume, and biofilm thickness only increased in the 50-h-old biofilm; however, no change was observed in 50-195-h-old biofilms. In addition, an increase in the biofilm density was observed over time. Conclusions: These results suggest that the acid production ability of cariogenic biofilms does not change, but the biofilm density increases over time. However, due to scientific information, further research needs to be conducted in the field of dentistry to get further insights on the progression of cariogenic biofilms over time.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.7
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• pp.964-969
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• 2006

The efficacy of garlic extract and $PGF_2{\alpha}$ in the treatment of endometritis in cows was evaluated. A total of 26 parous cows affected with endometritis were randomly allocated into three groups. Group I (n = 10) animals were infused (IU) with 10 ml garlic extract mixed with 90 ml normal saline, three times at 12 h interval starting from the day of estrum, whereas the animals of Group II (n = 10) were treated with a single injection of $PGF_2{\alpha}$ (25 mg Lutalyse) on the $10^{th}$ to $12^{th}$ day after estrus, and group III (n = 6) remained as control. Cervico-vaginal mucus (CVM) was collected from each animal at pre- and post-treatment estrus and subjected to white side test, pH determination and total bacterial load. The clinical recovery of cows was assessed by negative white side test reaction, pH value and total bacterial count of CVM at subsequent estrus. The recovered animals were inseminated with frozen-thawed semen twice at 12 h intervals and pregnancy was confirmed at 45-60 days following insemination. A significant decline (p<0.05) in pH of CVM was observed in both the treatment groups at subsequent estrus. After treatment there was a significant (p<0.05) reduction in bacterial load, whereas, it was increased in control group. A total number of 65 isolates were identified in CVM samples comprising mostly of facultative anaerobic bacteria. Plasma $T_4$ and $T_3$ concentrations were increased in all the treated animals, whereas, a decline was observed in cortisol levels following treatment. The overall conception rate was 50% in treated groups as compared to nil pregnancy in the control.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.7
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• pp.930-935
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• 2004

The present study was aimed to study the effect of aqueous extract of Tinospora cordifolia and autologous plasma on uterine infections. Buffaloes in estrus, 40 days and above postpartum were checked for uterine infections. Animals having uterine infections were randomly divided into three groups of six animals each. Buffaloes in group I, II and III (control) were given intrauterine infusion of aqueous extract of Tinospora cordifolia (3,000 mg total dose), autologous plasma (150 ml) and phosphate buffer saline (150 ml) respectively, in three divided doses, once daily for three consecutive days, starting from the day of estrus. A fourth group (IV) comprising of six buffaloes having no uterine infection was also included in the present study. Buffaloes were inseminated artificially on next estrus following treatment and confirmed for pregnancy 60 days later. Bacterial population in CVM of buffaloes in group I, II and III was significantly (p<0.05) higher than group IV. After treatment there was a significant (p<0.01) reduction in bacterial population in group I (83.496$\pm$7.755%) and group II 80.233$\pm$5.799%) than group in III 7.557$\pm$33.551%) at next estrus. There was non-significant improvement in first service conception rate (CR, 33.33%) and overall conception rate (OCR, 27.27%) in group I, in comparison to group III (first service CR-16.67%; OCR-20.0%). No significant improvement was seen in OCR (22.22%) in-group II also in comparison to group III. The improvement in group I was however, nonsignificantly lower than normal animals of group IV (First service CR-16.67%; OCR-36.33%).

• Asian-Australasian Journal of Animal Sciences
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• v.8 no.5
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• pp.449-454
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• 1995

The present study was conducted to assess gene expression of bacterial lacZ driven by the SV40 promoter at early developmental stages of bovine embryos. The lacZ gene was linearized with BamHI digestion and introduced into the pronucleus by microinjection at 20 hrs after the commencement of in vitro fertilization. Intact bovine blastocysts were not stained with X-Gal, suggesting that there is no endogenous beta-galactosidase activity in these blastocysts. In contrast, the bovine blastocyst cells microinjected with the lacZ gene exerted a characteristic greenish-blue color originating from the bacterial beta-galactosidase activity, albeit at a low rate, i.e. 2.1% of the total fertilized oocytes injected. It was concluded, therefore, that the lacZ gene driven by the SV40 promoter could be used for an indirect screening method in which the presence of transgene is evaluated from the product of transgene expression.

• Research in Plant Disease
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• v.30 no.2
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• pp.148-156
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• 2024

Ralstonia pseudosolanacearum, a plant pathogenic bacterium that can survive for a long time in soil and water, causes lethal wilt in the Solanaceae family. Sigma S is a part of the RNA polymerase complex, which regulates gene expression during bacterial stress response or stationary phase. In this study, we investigated the role of sigma S in R. pseudosolanacearum under stress conditions using a rpoS-defective mutant strain of R. pseudosolanacearum and its wild-type strain. The phenotypes of rpoS-defective mutant were complemented by introducing the original rpoS gene. There were no differences observed in bacterial growth rate and exopolysaccharide production between the wild-type strain and the rpoS mutant. However, the wild-type strain responded more sensitively to nutrient deficiency compared to the mutant strain. Under the nutrient deficiency, the rpoS mutant maintained a high bacterial viability for a longer period, while the viability of the wild-type strain declined rapidly. Furthermore, a significant difference in pH was observed between the culture supernatant of the wild-type strain and the mutant strain. The pH of the culture supernatant for the wild-type strain decreased rapidly during bacterial growth, leading to medium acidification. The rapid decline in the wild-type strain's viability may be associated with medium acidification and bacterial sensitivity to acidity during transition to the stationary phase. Interestingly, the rpoS mutant strain cannot utilize acetic acid, D-alanine, D-trehalose, and L-histidine. These results suggest that sigma S of R. pseudosolanacearum regulates the production or utilization of organic acids and controls cell death during stationary phase under nutrient deficiency.

• Microbiology and Biotechnology Letters
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• v.21 no.6
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• pp.622-627
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• 1993

Rhodospirillum rubrum P17 was used to investigate the pontential for the treatment of soybean curd waste and for the utilization of the biomass produced. The maximal biomass production and COD removal from the waste water were obtained at 30C, pH 7.0 under 2,500lux production and 50 rpm of agitation. The initial COD level of the soybean curd waste water was 3,240mg/l, and after 4 days of cultivation in batch culture, 3.46g/l of cells was obtained and COD level of the waste water reduced to 150mg/l (COD removal rate 95.4%).

• Asian-Australasian Journal of Animal Sciences
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• v.2 no.4
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• pp.615-623
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• 1989

Three sheep fitted with rumen cannulae and abomasal cannulae were given daily 750 g (DM) of three diets consisting of straw-manure silage and barley mixture in the ratios of 75:25, 50:50 and 25:75. As the proportion of barley in the diet increased, there was an increase in the amount of OM apparently digested in the rumen and thole tract (P<.01). But ADF digestion was decreased. For the 25:75 diet the $NH_3-N$ content in the rumen showed the highest value, but the total VFA was the lowest. The rumen volume and dilution rate increased with increasing ratio of silage in diets. There were no significant differences between diets in abomasal NAN flow, and the bacterial-N for the 25:75 diet was 7.3 g N as compared with 9.2-9.6 g N for the other diets (P<.01). Rates of bacterial nitrogen synthesis in the rumen were 30.5, 24.1 and 14.9 g N per Kg OM apparently digested in the rumen for the 75:25, 50:50 and 25:75 diets, respectively.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.4
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• pp.515-521
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• 2004

Anaerobic digestion has many advantages over the more conventional aerobic treatment processes such as low levels of excess sludge production, low space (area) requirements, and the production of valuable biogas. The purpose of this study was to evaluate the effect of organic loading rate of anaerobic digestion on thermophilic($55^{\circ}C$) and mesophilic($35^{\circ}C$) conditions. Fluorescent in situ hybridization (FISH) method was also used to study the microbial community in the reactors. The stabilizing time in mesophilic anaerobic reactors was shorter as approximately 20 days than 40 days in the thermophilic anaerobic reactors. The amount of methane production rate in anaerobic reactors was independent of the concentrations of supplied substrates and the amount of methanogens. When the microbial diversity in the mesophilic and thermophilic reactors, which had been treated with acetate-based artificial wastewater, were compared, it was found that methanogenesis was carried out by microbial consortia consisting of bacteria and archaea such as methanogens. To investigate the activity of bacterial and archaeal populations in all anaerobic reactors, the amount of acetate was measured. Archaea were predominant in all reactors. Interestingly, Methanothrix-like methanogens appeared in mesophilic anaerobic reactors with high feed substrate concentrations, whereas it was not observed in thermophilic anaerobic reactors.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.12-12
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• 2017

Genetic improvement in potato can be carried out through several approaches, as sexual crosses, somatic hybridization, mutation and genetic engineering. Although the approach is different, but the goal is the same, to get a superior cultivar. Mutation and genetic engineering are very interesting methods for genetic improvement of potato plants. Mutation by gamma-ray irradiation have been performed to get some new potato cultivars which are more resistant to disease and have higher productivity. We have carried out a mutation of some potato cultivars and obtained some excellent clones to be potentially released as new superior cultivars. By the mutation method, we have released one potato cultivar for the French fries industry, and we registered one cultivar of potato for chips, and two cultivar for vegetable potatoes. Actually we are doing multi-location trial for three clones to be released as new cultivars. Through genetic engineering, several genes have been introduced into the potato plant, and we obtained several clones of transgenic potato plants. Transgenic potato plants containing FBPase gene encoding for fructose bisphosphatase, have a higher rate of photosynthesis and higher tuber productivity than non-transgenic plants. This result suggests that FBPase plays an important role in increasing the rate of photosynthesis and potato tuber productivity. Some transgenic potatoes containing the Hd3a gene are currently being evaluated for their productivity. Over expression of the Hd3a gene is expected to increase tuber productivity and induce flowering in potatoes. Transgenic potato plants containing MmPMA gene encoding for plasma membrane ATPse are more tolerant to low pH than non-transgenic plants, indicating that plasma membrane ATPase plays an important role in the potato plant tolerance to low pH stress. Transgenic potato plants containing c-lysozyme genes, are highly tolerant of bacterial wilt diseases caused by Ralstonia solanacearum and bacterial soft rot disease caused by Pectobacterium carotovorum. Expression of c-lyzozyme gene plays an important role in increasing the resistance of potato plants to bacterial diseases.

• The Plant Pathology Journal
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• v.40 no.4
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• pp.346-357
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• 2024

This study was carried out to screen the antifungal activity against Colletotrichum acutatum, Colletotrichum dematium, and Colletotrichum coccodes. Bacterial isolate GP-P8 from pepper soil was found to be effective against the tested pathogens with an average inhibition rate of 70.7% in in vitro dual culture assays. 16S rRNA gene sequencing analysis result showed that the effective bacterial isolate as Bacillus siamensis. Biochemical characterization of GP-P8 was also performed. According to the results, protease and cellulose, siderophore production, phosphate solubilization, starch hydrolysis, and indole-3-acetic acid production were shown by the GP-P8. Using specific primers, genes involved in the production of antibiotics, such as iturin, fengycin, difficidin, bacilysin, bacillibactin, surfactin, macrolactin, and bacillaene were also detected in B. siamensis GP-P8. Identification and analysis of volatile organic compounds through solid phase microextraction/gas chromatography-mass spectrometry (SPME/GC-MS) revealed that acetoin and 2,3-butanediol were produced by isolate GP-P8. In vivo tests showed that GP-P8 significantly reduced the anthracnose disease caused by C. acutatum, and enhanced the growth of pepper plant. Reverse transcription polymerase chain reaction analysis of pepper fruits revealed that GP-P8 treated pepper plants showed increased expression of immune genes such as CaPR1, CaPR4, CaNPR1, CaMAPK4, CaJA2, and CaERF53. These results strongly suggest that GP-P8 could be a promising biocontrol agent against pepper anthracnose disease and possibly a pepper plant growth-promoting agent.