• Journal of Forest and Environmental Science
• /
• 제34권1호
• /
• pp.61-65
• /
• 2018

To know if small changes in rearing water temperature and density affect the number of bacterial and fungal colonies in metamorphosed frogs, Dybowski's frog tadpoles were reared from Gosner 25-26 stages at either low ($1^{\circ}C$ low to ambient water temperature), ambient, or high ($1^{\circ}C$ high) water temperature (each 15 tadpoles in 20 L water) condition and at either low (10 tadpoles/20 L water), medium (20 tadpoles), or high (30 tadpoles) density condition. Immediately after metamorphosis, we sampled bacteria and fungi from skin, liver, and heart of six metamorphosed frogs, randomly selected for each treatment group. After separate incubation of bacteria and fungi on 3M Petrifilm plates, we counted the number of bacterial and fungal colonies appeared on the plates and compared the numbers among the temperature and density treatment groups. For temperature treatment, high-temperature group had fewer bacterial colonies, while low-temperature group had more fungal colonies than the other two groups. For density treatment, low-density group had fewer bacterial colonies than the other two groups, but the number of fungal colonies were not different among the groups. Our results suggest that small increased rearing water temperature and lowered rearing density could potentially reduce pathogens in farming frogs.

• Journal of Ecology and Environment
• /
• 제38권3호
• /
• pp.375-381
• /
• 2015

We investigated the influence of summer rainfall on Pectinatella magnifica colonies in lotic ecosystems. Of the examined substrate materials, branches and aquatic macrophytes supported more colonies of P. magnifica than that by stones or artificial materials. The influence of rainfall on P. magnifica colonies differed in accordance with the type of substrate material at each study site. In the Geum River, little difference was noted in the number of P. magnifica colonies on branches before ($mean{\pm}SE$, $24{\pm}7.3$ individuals) and after rainfall ($20{\pm}8.4$ ind.); other substrate types supported fewer colonies of P. magnifica after rainfall. In contrast, in the Miryang River, rainfall had minimal effect on the number of P. magnifica colonies supported by macrophytes ($13{\pm}3.8$ and $12{\pm}4.3$ ind., respectively). Artificial material was more abundant in the Banbyeon Stream where it was able to support more colonies of P. magnifica. We found that the structure of different substrates sustains P. magnifica following rainfall. In the Miryang River, free-floating and submerged plants with a relatively heterogeneous substrate surface were the dominant macrophytes, whereas in the Geum River, simple macrophytes (i.e., emergent plants) were dominant. Therefore, we conclude that the substrate type on which P. magnifica grows plays an important role in resisting physical disturbances such as rainfall.

• 한국동물위생학회지
• /
• 제36권1호
• /
• pp.37-44
• /
• 2013

The ecologically and economically important honeybee species are susceptible to infections by various pathogens. This study was investigated to detect infectious pathogens in honeybee colonies reared in eastern Gyeongbuk province by PCR in 2010~2011. A total of 11 infectious pathogens, including 6 viruses, 2 bacteria, 2 fungi, and 1 parasite, were investigated in honeybee colonies suffering from symptoms of sudden collapse, depopulation, or paralysis. The infectious pathogens and infection rates among 24 honeybee colonies detected were as follows: sacbrood virus (66.7%), deformed wing virus (4.2%), black queen cell virus (12.5%), Kashmir bee virus (29.2%), American foulbrood (41.7%), European foulbrood (12.5%), stonebrood (45.8%), chalkbrood (4.2%), and Nosema (33.3%), respectively. Since the coinfection rates of multiple pathogens were detected high in honeybee colonies reared in eastern Gyeongbuk province, large-scale investigation and appropriate control programs need to be established in this region.

• Journal of Microbiology
• /
• 제43권2호
• /
• pp.204-208
• /
• 2005

The objective of this study was to both isolate and identify non-mutans streptococci organisms (non­MSO) from dental plaques recovered on mitis-salivarius sucrose bacitracin agar (MSB) plates. The dental plaque samples, which had been collected from 63 human subjects, were diluted and plated on MSB. The bacteria growing on the MSB plates were then identified with biochemical tests, as well as with 16S rDNA cloning and sequencing techniques. Our data indicated that bacteria from 30 subjects had been recovered on the MSB plates. Among the 21 typical colonies selected from the 30 subjects, 12 colonies, derived from 10 subjects, were identified as non-MSO. These 12 colonies were determined to be Streptococcus anginosus (8 colonies), S. sanguinis (1 colony), and Pantoea agglomerans (3 colonies). These results strongly suggest that a new selective medium will be required for the reliable isolation of mutans streptococci.

• Journal of Microbiology
• /
• 제39권4호
• /
• pp.321-325
• /
• 2001

Baird-Parker agar with egg yolk/tellurite emulsion (BPA) is widely accepted as a medium for the enu-meration of Staphylococcus aureus in foods. Howerver, it is not vompletely selective and colonies of other genera of species could be similar to those of Staphylococcus aureus. Moreover, the strains of Staphylococcus aureus that are lecithinase negatrive could go unnoticed. Both facts could affect the counts. The aim of this study was to dtermine whether the enumeration of the colonies with the typical morphol-ogy of Staphylococcus aureus on BPA is sufficien to quantity this species in poultry meat. Forty chiken carcasses were tested for Staphylococcus aureus by surface plating using BPA, Results indicate that the predictiv value of the morphoogy of the colonies of BPA is 85.71% and 68.42% for typical and atypical colonies of Staphylococcus aureus, respectively. However, Staphylococcus aureus counts (after identification) and counts of typical colonies did not show any significant differences(P>0.05) and are significantly(P<0.001) correlated (r=0.996).These results suggest that , for screening purposes. enumeration of Staphylococcus aureus from poultry meat does not require any identification of stains. resulting in a saving of time and money.

• 대한의생명과학회지
• /
• 제25권4호
• /
• pp.367-371
• /
• 2019

In this study, the author observed the fungal characteristics of T. verrucosum which is commonly known as the cattle ringworm fungus in the farms of Hoengseong, Gangwon-do. After isolating 20 strains of T. verrucosum from cattle, they were cultured on SDA, PDA media and the fungal characteristics were concluded through visual observation of the colonies, microscopic findings, hair perforation test and urease test. The size of the colonies cultured on SDA media at 37 C was on an average 5 mm at 1 week, 33 mm at 2 weeks, 42 mm at 3 weeks and 58 mm after 4 weeks. Observing the characteristics of the colonies, 17 strains of T. album showing central bold radial folds, 2 strains of T. ochraceum having l throughout the colonies and 1 strain of T. discoides with rapid growth rate and gray-white cotton patterns were found. On microscopic observations of the cultured colonies on SDA, PDA media, macroconidia and microconidia were not found in T. verrucosum and hyphae and chlamydospore were only seen in T. album types. Out of 20 strains of T. verrucosum, hair perforation test was positive on only 3 strains and urease test was positive on all of the 20 strains.

• 생명과학회지
• /
• 제9권3호
• /
• pp.314-327
• /
• 1999

This study was investigated to isolate identify the total bacteria and fungi from the indoor air of work-place of the shoes, paint, stainless steel, and plastic industries. The number of bacterial colonies on the nutrient agar plates were calculated by the open petridish method for 30 minutes in indoor air of work-places at the autumn and winter. The isolated bacteria were identified by Gram stain and biochemical test using API Staph and API 20E kits. The isolated fungal colonies were identified by gross appearance of the giant colonies and microscopic examination of their spore and hyphal characteristics on the slide culture method. The minimum inhibitory concentration (MIC) of several antibiotics against isolated bacteria was determined by the microdilution method with Mueller-Hinton broth. The 70-400 colonies in autumn and 54-236 colonies in winter were isolated from the indoor air of work-places of several industry. The isolation rates of Gram positive cocci, Gram positive bacilli, Gram negative bacilli, and Gram negative cocci were 46.3%, 19.8%, 17.3%, and 16.1%, respectively. In Gram positive cocci, the most strains were identified as Aerococcus spp, Micrococcus spp, and Staphylococcus spp. In Gram positive and negative bacilli, and Gram negative cocci were identified as Bacillus spp, Pseudomonas spp, and Neisseria spp, respectively. The frequently isolated fungi were Aspergillus spp, Penicillium spp and Rhizopus spp, respectively. The frequently isolated Aerococcus spp, Micrococcus spp, and Staphylococus spp were highly resistance against ampicillin, erythromycin, methicillin, and tetracycline. These results arouse our attention to microbiologic pollution in the indoor air of work-places of industries.

• Journal of Microbiology and Biotechnology
• /
• 제19권1호
• /
• pp.78-82
• /
• 2009

Eight commercially packaged kimchi products were examined over 15 days of storage at $4^{\circ}C$ to evaluate the occurrence of Hafnia alvei (H. alvei). Additionally, 7 saeujeot products, as a possible ingredient source, were analyzed to examine the bacteria's origin. Over the storage period, kimchi samples had decreasing pH levels, which stabilized at pH 4.2; acidity increased to $0.9{\pm}0.1%$. Lactose-nonfermenting bacteria, which H. alvei belongs to, gradually reduced in numbers over the kimchi storage. However, the relative frequency of H. alvei to lactose-nonfermenting bacteria tended to increase. From the kimchi samples, 58 H. alvei-presumptive colonies were selected. Forty three colonies turned out to be H. alvei and 15 colonies were identified as other strains or uncertain identifications when the API 20E system was used. From further test, 3 of the 43 colonies were H. alvei (-) against the phage test. Finally, H. alvei was isolated from saeujeot, indicating that this ingredient can be an originating source of H. alvei in kimchi.

• Journal of Dairy Science and Biotechnology
• /
• 제39권1호
• /
• pp.9-19
• /
• 2021

Enterobacter sakazakii (Cronobacter spp.) causes meningitis, necrotizing enterocolitis, sepsis, and bacteremia in neonates and children and has a high mortality rate. For rapid E. sakazakii detection, various differential and selective media containing α-glucosidase substrates, such as 5-bromo-4-chloro-3-indolyl-α-D-glucopyranoside (BCIG) or 4-methylumbelliferyl-α-D-glucoside (α-MUG), have been developed as only E. sakazakii exhibits α-glucosidase activity in the genus Enterobacter. However, Escherichia vulneris (family: Enterobacteriaceae) can also utilize α-glucosidase substrates, thereby resulting in false positives. Various iron sources are known to promote the growth of gram-negative bacteria. This study aimed to develop a selective medium containing α-glucosidase substrates for E. sakazakii detection that would eliminate false positives, such as those of E. vulneris, and to determine the role of iron source in the medium. Three previously developed (TPD) media, i.e., Oxoid, OK, and VRBG, and the medium developed in this study, i.e., NGTE, were evaluated using 58 E. sakazakii and 5 non-E. sakazakii strains. Fifty-four E. sakazakii strains appeared as fluorescent or chromogenic colonies on all four media that were assessed. Two strains showed colonies on NGTE medium and not on TPD media. In contrast, the remaining two strains showed colonies on TPD media and not on NGTE medium. None of the non-E. sakazakii strains showed fluorescent or chromogenic colonies on any of the evaluated media except E. vulneris, which showed colonies on TPD media and not on NGTE medium. This study demonstrated that the newly developed NGTE medium was not only equally efficient in promoting the growth of bacterial colonies when compared with the currently available media but also eliminated false positives, such as E. vulneris.

• Animal Bioscience
• /
• 제36권8호
• /
• pp.1209-1220
• /
• 2023

Objective: The use of probiotics as an alternative to antibiotics in animal feed has received considerable attention in recent decades. Lactic acid bacteria (LAB) have remarkable functional properties promoting host health and are major microorganisms for probiotic purposes. The aim of this study was to characterize LAB strains of the chicken digestive tract and to determine their functional properties for further use as potential probiotics in poultry. Methods: A total of 2,000 colonies were isolated from the ileum and cecal contents of the chickens based on their phenotypic profiles and followed by a preliminary detection for acid and bile tolerance. The selected 200 LAB isolates with exhibited well-tolerance in acid and bile conditions were then identified by sequencing the 16S rDNA gene, followed by acid and bile tolerance, antimicrobial activity, adhesion to epithelial cells and additional characteristics on the removal of cholesterol. Then, the two probiotic strains (L. ingluviei and L. salivarious) which showed the greatest advantage in vitro testing were selected to assess their efficacy in broiler chickens. Results: It was found that 200 LAB isolates that complied with all measurement criteria belonged to five strains, including L. acidophilus (63 colonies), L. ingluviei (2 colonies), L. reuteri (58 colonies), L. salivarius (72 colonies), and L. saerimneri (5 colonies). We found that the L. ingluviei and L. salivarius can increase the population of LAB and Bifidobacterium spp. while reducing Enterobacteria spp. and Escherichia coli in the cecal content of chickens. Additionally, increased concentrations of valeric acid and short chain fatty acids were also observed. Conclusion: This study indicates that all five Lactobacillus strains isolated from gut contents of chickens are safe and possess probiotic properties, especially L. ingluviei and L. salivarius. Future studies should evaluate the potential for growth improvement in broilers.