• Ocean and Polar Research
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• 제35권4호
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• pp.415-425
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• 2013

In order to understand phytoplankton and bacterial distribution in tropical coral reef ecosystems in relation to the mangrove community, their biomass and activities were measured in the sea waters of the Chuuk and the Kosrae lagoons located in Micronesia. Chlorophyll a and bacterial abundance showed maximal values in the seawater near the mangrove forests, and then steeply decreased as the distance increased from the mangrove forests, indicating that environmental conditions for these microorganisms changed greatly in lagoon waters. Together with chlorophyll a, abundance of Synechococcus and phototrophic picoeukaryotes and a variety of indicator pigments for dinoflagellates, diatoms, green algae and cryptophytes also showed similar spatial distribution patterns, suggesting that phytoplankton assemblages respond to the environmental gradient by changing community compositions. In addition, primary production and bacterial production were also highest in the bay surrounded by mangrove forest and lowest outside of the lagoon. These results suggest that mangrove waters play an important role in energy production and nutrient cycling in tropical coasts, undoubtedly receiving large inputs of organic matter from shore vegetation such as mangroves. However, the steep decrease of biomass and production of phytoplankton and heterotrophic bacteria within a short distance from the bay to the level of oligotrophic waters indicates that the effect of mangrove waters does not extend far away.

• Asian-Australasian Journal of Animal Sciences
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• 제27권12호
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• pp.1726-1735
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• 2014

This study investigated the effects of acarbose addition on changes in ruminal fermentation characteristics and the composition of the ruminal bacterial community in vitro using batch cultures. Rumen fluid was collected from the rumens of three cannulated Holstein cattle fed forage ad libitum that was supplemented with 6 kg of concentrate. The batch cultures consisted of 8 mL of strained rumen fluid in 40 mL of an anaerobic buffer containing 0.49 g of corn grain, 0.21 g of soybean meal, 0.15 g of alfalfa and 0.15g of Leymus chinensis. Acarbose was added to incubation bottles to achieve final concentrations of 0.1, 0.2, and 0.4 mg/mL. After incubation for 24 h, the addition of acarbose linearly decreased (p<0.05) the total gas production and the concentrations of acetate, propionate, butyrate, total volatile fatty acids, lactate and lipopolysaccharide (LPS). It also linearly increased (p<0.05) the ratio of acetate to propionate, the concentrations of isovalerate, valerate and ammonia-nitrogen and the pH value compared with the control. Pyrosequencing of the 16S rRNA gene showed that the addition of acarbose decreased (p<0.05) the proportion of Firmicutes and Proteobacteria and increased (p<0.05) the percentage of Bacteroidetes, Fibrobacteres, and Synergistetes compared with the control. A principal coordinates analysis plot based on unweighted UniFrac values and molecular variance analysis revealed that the structure of the ruminal bacterial communities in the control was different to that of the ruminal microbiota in the acarbose group. In conclusion, acarbose addition can affect the composition of the ruminal microbial community and may be potentially useful for preventing the occurrence of ruminal acidosis and the accumulation of LPS in the rumen.

• Journal of Microbiology and Biotechnology
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• 제23권1호
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• pp.76-84
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• 2013

A polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) technique followed by sequencing of the 16S rDNA fragments eluted from the bands of interest on denaturing gradient gels was used to monitor changes in the bacterial microflora of two commercial kimchi, salted cabbage, and ingredient mix samples during 30 days of fermentation at $4^{\circ}C$ and $10^{\circ}C$. Leuconostoc (Lc.) was the dominant lactic acid bacteria (LAB) over Lactobacillus (Lb.) species at $4^{\circ}C$. Weissella confusa was detected in the ingredient mix and also in kimchi samples throughout fermentation in both samples at $4^{\circ}C$ and $10^{\circ}C$. Lc. gelidum was detected as the dominant LAB at $4^{\circ}C$ in both samples. The temperature affected the LAB profile of kimchi by varing the pH, which was primarily caused by the temperature-dependent competition among different LAB species in kimchi. At $4^{\circ}C$, the sample variations in pH and titratable acidity were more conspicuous owing to the delayed growth of LAB. Temperature affected only initial decreases in pH and initial increases in viable cell counts, but affected both the initial increases and final values of titratable acidity. The initial microflora in the kimchi sample was probably determined by the microflora of the ingredient mix, not by that of the salted cabbage. The microbial distributions in the samples used in this study resembled across the different kimchi samples and the different fermentation temperatures as the numbers of LAB increased and titratable acidity decreased.

• 한국유기농업학회지
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• 제19권spc호
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• pp.190-193
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• 2011

Organic and chemical fertilizer amendments are an important agricultural practice for increasing crop yields. In order to maintain the soil sustainability, it is important to monitor the effects of fertilizer applications on the shift of soil microorganism, which control the cycling of many nutrients in the soils. Here, culture-dependent and culture-independent approaches were used to analyze the soil microorganism and community structure under six fertilization treatments, including green manure, rice straw compost, rapeseed cake, pig mature compost, NPK +pig mature compost, NPK and control. Both organic and chemical fertilizers caused a shift of the cultural microorganism CFUs after treatments. Bacterial CFUs of the organic fertilization treatments were significantly higher than that of chemical fertilization treatments. The DGGE profiles of the bacterial communities of the samples showed that the green manure treatment was a distinct difference in bacterial community, with a greater complexity of the band pattern than other treatments. Cluster analyses based on the DGGE profile showed that rice straw compost and pig mature compost had a similar banding pattern and clustered together firstly. Rapeseed cake, NPK, NPK +pig manure compost and control clustered together in other sub-cluster and clearly distinguished from green manure.

• Journal of Microbiology and Biotechnology
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• 제29권4호
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• pp.527-537
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• 2019

Three types of meongge (Halocynthia roretzi) jeotgal (MJ) were prepared with 3 different types of salts (12%, w/v): purified salt (PS), solar salt aged for 3 years (SS), and bamboo salt that had been recrystalized 3 times (BS). One set of MJ was fermented with starters, Bacillus subtilis JS2 and Tetragenococcus halophilus BS1-37 (each 6 log CFU/g), and another set without starters for 42 days at $10^{\circ}C$. The LAB count of the SSMJ (non-starter) was highest at day 28 (2.30 log CFU/g). The pH of the PSMJ and SSMJ was 5.72-5.77 at day 0, and 5.40-5.50 at day 42. BSMJ showed higher pH and lower titratable acidities than other samples. Amino-type nitrogen (ANN) increased continuously, and SSMJ showed higher values than other samples from day 14. Bacterial species of non-starter MJ were examined by culture independent method. Clone libraries of 16S rRNA genes were constructed in Escherichia coli from total DNA from non-starter MJ samples at day 0, 14, and 28. Thirty clones per each sample were randomly selected and DNA sequences were analyzed. Variovorax sp., uncultured bacterium, and Acidovorax sp. were the most dominant group at day 0, 14, and 28, respectively. Lactobacillus sakei and Streptococcus sp. were the next dominant group in SSMJ at day 28. A Streptococcus sp. was detected from PSMJ at day 28. Sensory evaluation for MJ samples at day 28 showed that SSMJ got higher overall acceptability scores. These results showed that solar salt can cause desirable changes in the microbial community of fermented foods, thereby positively affecting their overall quality.

• Animal Bioscience
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• 제36권1호
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• pp.63-74
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• 2023

Objective: The objective of this study was to investigate the effects of feeding active dry yeast (ADY) and yeast culture (YC) on fecal bacterial community in finishing bulls fed high-concentrate diets in the same experimental environment. Methods: Forty-five healthy finishing cattle (Simmental×Chinese Luxi yellow bulls; 24 months; 505±29 kg) were randomly divided into three groups: i) CON group (control group, only fed basal diet), ii) ADY group (fed basal diet + active dry yeast), and iii) YC group (fed basal diet + yeast culture). At the end of the trial, nine rectum fecal samples were randomly selected from each group for bacterial DNA sequencing. Results: There was no difference among groups about alpha diversity indices (all p>0.05), including ACE, Chao 1, Shannon, and Simpson indices. Principal component analysis and non-metric multidimensional scaling analysis showed a high similarity among three groups. Compared with CON group, ADY and YC groups had greater relative abundance of c_Clostridia, o_Oscillospirales, and f_Oscillospiraceae, but lesser relative abundance of g_Megasphaera, and s_Megasphaera_elsdenii (all p<0.01). And, the relative abundances of p_Firmicutes (p = 0.03), s_Prevotella_sp (p = 0.03), o_Clostridiales (p<0.01), g_Clostridium (p<0.01), f_Caloramatoraceae (p<0.01), and f_Ruminococcaceae (p = 0.04) were increased in the ADY group. The PICRUSt2 prediction results showed that the metabolic pathways had no significant differences among groups (p>0.05). Besides, the relative abundance of c_Clostridia (r = 0.42), and f_Oscillospiraceae (r = 0.40) were positively correlated to average daily gain of finishing bulls (p<0.05). Conclusion: Both of ADY and YC had no effect on diversity of fecal bacteria in finishing bulls, but the supplementation of ADY and YC can improve the large intestinal function in finishing bulls by increasing the abundance of cellulolytic bacteria and altering the abundance of lactic acid-utilizing bacteria.

• Asian-Australasian Journal of Animal Sciences
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• 제33권1호
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• pp.166-176
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• 2020

Objective: An experiment was conducted to determine the effects of L-arginine (L-Arg) and N-carbamoylglutamic acid (NCG) on the growth, metabolism, immunity and community of cecal bacterial flora of weanling and young rabbits. Methods: Eighteen normal-grade male weanling Japanese White rabbits (JWR) were selected and randomly divided into 6 groups with or without L-Arg and NCG supplementation. The whole feeding process was divided into weanling stage (day 37 to 65) and young stage (day 66 to 85). The effects of L-Arg and NCG on the growth, metabolism, immunity and development of the ileum and jejunum were compared via nutrient metabolism experiments and histological assessment. The different communities of cecal bacterial flora affected by L-Arg and NCG were assessed using high-throughput sequencing technology and bioinformatics analysis. Results: The addition of L-Arg and NCG enhanced the growth of weanling and young rabbit by increasing the nitrogen metabolism, protein efficiency ratio, and biological value, as well as feed intake and daily weight gain. Both L-Arg and NCG increased the concentration of immunoglobulin A (IgA), IgM, and IgG. NCG was superior to L-Arg in promoting intestinal villus development by increasing villus height, villus height/crypt depth index, and reducing the crypt depth. The effects of L-Arg and NCG on the cecal bacterial flora were mainly concentrated in different genera, including Parabacteroides, Roseburia, dgA-11_gut_group, Alistipes, Bacteroides, and Ruminococcaceae_UCG-005. These bacteria function mainly in amino acid transport and metabolism, energy production and conversion, lipid transport and metabolism, recombination and repair, cell cycle control, cell division, and cell motility. Conclusion: L-Arg and NCG can promote the growth and immunity of weanling and young JWR, as well as effecting the jejunum and ileum villi. L-Arg and NCG have different effects in the promotion of nutrient utilization, relieving inflammation and enhancing adaptability through regulating microbial community.

• 농업생명과학연구
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• 제50권1호
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• pp.117-124
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• 2016

토양 미생물 군집은 외부 환경변화에 있어 식물 군집보다 더 빨리 반응할 수 있다는 점에서 복원 과정의 초기 지표로 활용될 수 있다. 이런 측면에서 인위적인 교란에 대한 생태계 반응을 측정하고 생태계 복원의 지표를 제공하는 토양 미생물 군집 연구가 증가하고 있는 추세이다. 본 연구는 2012년과 2013년 준공된 이화령과 육십령 백두대간 생태축 복원사업지와 주변 임분에서 각각 토양을 채취하여 16S rRNA 파이로시퀀싱 기법을 이용하여 토양 박테리아 군집을 분석하였다. 문(Phylum) 수준에서의 박테리아 다양성은 이화령이 평균 29.3, 육십령이 평균 32.3으로 나왔고 복원사업지와 주변 임분은 통계적으로 유의한 차이를 보였으나(p<0.01), 지리적 위치(이화령과 육십령 비교)나 토심(0~15cm, 16~30cm 비교)에 따른 유의한 영향은 나타나지 않았다. 검색된 토양 박테리아 중에서 Acidobacteria(37.3%)와 Proteobacteria(31.1%)가 가장 우점적으로 분포하는 것으로 나타났으며, 복원한 토양과 주변 임분에서 이 두 문의 박테리아 다양성 양상은 서로 상반되었다. 즉, 인공적으로 복원된 토양에서는 Proteobacteria가 높은 비율로 나타났고(38.1%, 인근 산림토양에서는 24.2%), 주변 임분에서는 Acidobacteria가 다양한 것으로 나타났다(55.4%, 복원 사업지는 19.2%). 이러한 경향은 토양의 영양상태에 따라 선호하는 박테리아 종류가 다르다는 기존의 연구 결과와 유사하였으며, 특히 Acidobacteria는 산성토양을 선호하는 등 토양산도와 밀접한 연관이 있을 것으로 생각된다. 따라서, 토양 박테리아 군집 특성은 연구지 위치나 토심에 따른 영향보다는 토양복원에 따른 영향이 더 크게 나타났고 이는 향후 토양복원의 성공여부를 정량적으로 모니터링하는데 활용될 수 있을 것으로 기대한다.

• Journal of Microbiology and Biotechnology
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• 제23권12호
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• pp.1774-1778
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• 2013

Methylotrophs within biological activated carbon (BAC) systems have not received attention although they are a valuable biological resource for degradation of organic pollutants. In this study, methylotrophic populations were monitored for four consecutive seasons in BAC of an actual drinking water plant, using ribosomal tag pyrosequencing. Methylotrophs constituted up to 5.6% of the bacterial community, and the methanotrophs Methylosoma and Methylobacter were most abundant. Community comparison showed that the temperature was an important factor affecting community composition, since it had an impact on the growth of particular methylotrophic genera. These results demonstrated that BAC possesses a substantial methylotrophic activity and harbors the relevant microbes.

• 생명과학회지
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• 제17권9호통권89호
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• pp.1284-1289
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• 2007

정수처리 공정에서 생물활성탄 (BAC) 공정은 미생물의 유기물 제거능을 극대화시킨 일종의 생물여과 공정이다 BAC 공정은 유기물과 미생물 재성장능을 효과적으로 제거한다. BAC 공정은 그 수계에 존재하는 미생물들이 활성탄에 부착 ${\cdot}$ 서식하며 수중의 천연유기물질을 기질로 이용하기 때문에 그 수계에 서식하는 미생물 종들에 매우 의존적이다. 본 연구는 낙동강 하류의 배리취수장 원수를 사용하여 생물활성탄에 의한 pilot-plant 공정을 운전하면서 SAC 공정에서의 활성탄 재질별로 배양작 (평판배양법) 및 비배양적 방법 (FISH)을 이용하여 SAC 부착세균의 군집구조 특성을 조사하였다. 실험결과 석탄계 재질의 부착세균 HPC 및 생산력이 각각 $1.20{\times}l0^7{\sim}56.2{\times}l0^7$ CFU/g, $1.2{\sim}3.7\;mg-C/m^3{\cdot}h$ 의 범위를 보여 세균 생체량과 DOC 제거율은 석탄계 재질이 가장 높은 것으로 나타났다. 배양적 방법으로 활성탄 재질별 부착세균을 동정한 결과 Pseudomonas 속이 우접하였고, 그 다음으로 Flavobacterium 속, Alcaligenes 속, Acinetobacter 속, Sphingomonas 속 등의 순으로 동정되었다. 또한, Pseudomonas 속 중 석탄계와 야자계 BAC에서는 Pseudomonas vesicularis, 목탄계 BAC에서는 Pseudomonas cepacia가 우점종으로 분포하였다. 비배양적 방법인 FISH 법을 이용한 세균 군집구조 조사결과 활성탄 재질별로 ${\alpha}$군집 27.0 ${\sim}$ 43.0%, ${\gamma}$ 군집 11.3 ${\sim}$ 28.6%, ${\beta}$ 군집 7.1 ${\sim}$ 22.0% 비율로 나타나 유기물 제거효율은 주로 ${\alpha}$ 군집에 의해 조절되어짐을 알 수 있었다.