• Journal of The Korean Society of Grassland and Forage Science
• /
• v.39 no.4
• /
• pp.227-234
• /
• 2019

This study was performed to investigate the effect of heat-stressed environment on rumen microbial diversity in Holstein cows. Rectal temperature and respiration rate were measured and rumen fluid was collected under normal environment (NE; Temperature humidity index (THI)=64.6) and heat-stressed environment (HE; THI=87.2) from 10 Holstein cows (60±17.7 months, 717±64.4 kg) fed on the basis of dairy feeding management in National Institute of Animal Science. The rumen bacteria diversity was analyzed by using the Illumina HiSeq^TM 4000 platform. The rectal temperature and respiratory rate were increased by 1.5℃ and 53 breaths/min in HE compared to that in NE, respectively. In this study, HE exposure induced significant changes of ruminal microbe. At phylum level, Fibrobacteres were increased in HE. At genus level, Ruminococcaceae bacterium P7 and YAD3003, Butyrivibrio sp. AE2032, Erysipelotrichaceae bacterium NK3D112, Bifidobacterium pseudolongum, Lachnospiraceae bacterium FE2018, XBB2008, and AC2029, Eubacterium celulosolvens, Clostridium hathewayi, and Butyrivibrio hungatei were decreased in HE, while Choristoneura murinana nucleopolyhedrovirus, Calothrix parasitica, Nostoc sp. KVJ20, Anabaena sp. ATCC 33047, Fibrobacter sp. UWB13 and sp. UWB5, Lachnospiraceae bacterium G41, and Xanthomonas arboricola were increased in HE. In conclusion, HE might have an effect to change the rumen microbial community in Holstein cows.

• Korean Journal of Food Science and Technology
• /
• v.38 no.1
• /
• pp.104-108
• /
• 2006

Water extracts of Jehotang were evaluated for their growth-promoting effects on Bifidobacterium longum, Lactobacillus sp., L. acidophilus, and Clostridium perfringens. Addition of Jehotang water extract to modified EG media at 0.1 mg/mL increased growths of B. longum, Lactobacillus sp., and L. acidophilus, with 1.8-fold increase in growth of L. acidophilus compared to that of control. Studies on these strains by agar diffusion method showed Lactobacillus sp. and L. acidophilus were activated by addition of Jehotang extract at 10 mg/disc. Proliferation responses of mice splenocytes and Peyer's patch cells to ConA by LPS-stimulation at 500 mg/kg B.W./day Jehotang extract were investigated in vitro. Upon treatment of 1 mg/mL Jehotang water extract to mice, proliferations of splenocytes and Peyer's patch cells increased 1.4- and 1.6-fold compared to control, respectively. In mice administered Jehotang extract, production of intestinal secretory IgA (sIgA) increased 2.4-fold compared to control. These results indicate water extract of Jehotang stimulated intestinal immune system of mice. In mice treated with Jehotang extract, production of lymphocytes was 4% lower, whereas those of granulocytes and platelets were 4% and slightly higher than control, respectively.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.12 no.1
• /
• pp.49-57
• /
• 2004

The effect of gas sparging on continuous fermentative $H_2$ production was investigated using external gases ($N_2$, $CO_2$) with various flow rates (100, 200, 300, 400 ml/min). Gas sparging showed a higher $H_2$ yield than no sparging, indicating that the decrease of $H_2$ partial pressure by gas sparging had a good effect on $H_2$ fermentation. Especially, $CO_2$ sparging was more effective in the reactor performance than $N_2$ sparging. The composition of butyrate, the main metabolic product of $H_2$ fermentation by Clostridium sp., was much higher in $CO_2$ sparging. $H_2$ production increased with increasing flow rate only in $CO_2$ sparging. The best performance was obtained by $CO_2$ sparging at 300 ml/min, resulting in the highest $H_2$ yield of 1.65 mol $H_2/mol$ hexoseconsumed and the maximum $H_2$ production of 6.77 L $H_2/g$ VSS/day. Compared to $N_2$ sparging, there could be another beneficial effect in $CO_2$ sparging apart from lowering down the $H_2$ partial pressure. High partial pressure of $CO_2$ had little effect on $H_2$ producing bacteria but inhibitory effect on other microorganisms like lactic acid bacteria and acetogens which were competitive with $H_2$ producing bacteria.

• KSBB Journal
• /
• v.29 no.6
• /
• pp.443-447
• /
• 2014

Biosynthesis of lactate-containing polyhydroxyalkanoates (PHAs) was examined in recombinant Escherichia coli W strain from sucrose. The Pseudomonas sp. MBEL 6-19 phaC1437 gene and the Clostridium propionicum pct540 gene, which encode engineered Pseudomonas sp. MBEL 6-19 PHA synthase 1 ($PhaC1_{Ps6-19}$) and engineered C. propionicum propionyl-CoA transferase ($Pct_{Cp}$), respectively, were expressed in E. coli W to construct key metabolic pathway to produce poly(3-hydroxybutyrate-co-lactate) [P(3HB-co-LA)]. The recombinant E. coli W expressing the phaC1437 gene and the pct540 gene could synthesize P(3HB-co-13mol%LA) up to the polymer content of 31.3 wt% when it was cultured in chemically defined MR medium containing 20 g/L of sucrose and 2 g/L of sodium 3-hydroxybutyrate. When Ralstonia eutropha phaAB genes were additionally expressed to provide 3-hydroxybutyrate-CoA (3HB-CoA) from sucrose, P(3HB-co-16mol%LA) could be synthesized from sucrose as a sole carbon source without supplement of sodium 3-hydroxybutyrate in culture medium, but the PHA content was decreased to 12.2 wt%. The molecular weight of P(3HB-co-16 mol%LA) synthesized in E. coli W using sucrose as carbon source were $1.53{\times}10^4$ ($M_n$) and $2.78{\times}10^4$ ($M_w$), respectively, which are not different from those that have previously been reported by other recombinant E. coli strains. Engineered E. coli strains developed in this study should be useful for the production of lactate-containing PHAs from sucrose, one of the most abundant and least expensive carbon sources.

• KSBB Journal
• /
• v.31 no.1
• /
• pp.27-32
• /
• 2016

Several CoA transferases from Clostridium beijerinckii, C. perfringens and Klebsiella pneumoniae were examined for biosynthesis of lactate-containing polyhydroxyalkanoates (PHAs) in recombinant Escherichia coli XL1-Blue strain. The CB3819 gene and the CB4543 gene from C. beijerinckii, the pct gene from C. perfringens and the pct gene from K. pneumoniae, which encodes putative CoA transferase gene, respectively, was co-expressed with the Pseudomonas sp. MBEL 6-19 phaC1437 gene encoding engineered Pseudomonas sp. MBEL 6-19 PHA synthase 1 ($PhaC1_{Ps6-19}$) to examine its activity for the construction of key metabolic pathway to produce poly(3-hydroxybutyrate-co-lactate) [P(3HB-co-LA)]. The recombinant E. coli XL1-Blue expressing the phaC1437 gene and CB3819 gene synthesized poly(3-hydroxybutyrate) [P(3HB)] homopolymer to the P(3HB) content of 60.5 wt% when it was cultured in a chemically defined medium containing 20 g/L of glucose and 2 g/L of sodium 3-hydroxybutyrate. Expression of the phaC1437 gene and CB4543 gene in recombinant E. coli XL1-Blue also produced P(3HB) homopolymer to the P(3HB) content of 51.2 wt% in the same culture condition. Expression of the phaC1437 gene and the K. pneumoniae pct gene in recombinant E. coli XL1-Blue could not result in the production of PHAs in the same culture condition. However, the recombinant E. coli XL1-Blue expressing the phaC1437 gene and the C. perfringens gene could produce poly(3-hydroxybutyrate-co-lactate [P(86.4mol%3HB-co-13.7 mol%LA) up to the PHA content of 10.6 wt% in the same culture condition. Newly examined CoA transfereases in this study may be useful for the construction of engineered E. coli strains to produce PHA containing novel monomer such lactate.

• Journal of Microbiology
• /
• v.45 no.2
• /
• pp.113-121
• /
• 2007

The bacterial diversity inherent to the biofilm community structure of a modified rotating biological contactor wastewater treatment process, referred to as the Rotating Activated Bacillus Contactor (RABC) process, was characterized in this study, via both culture-dependent and culture-independent methods. On the basis of culture-dependent methods, Bacillus sp. were found to exist in large numbers on the biofilm (6.5% of the heterotrophic bacteria) and the microbial composition of the biofilms was quite simple. Only three phyla were identified-namely, the Proteobacteria, the Actinobacteria (High G+C Gram-positive bacteria), and the Firmicutes (Low G+C Gram-positive bacteria). The culture-independent partial 16S rDNA sequence analysis revealed a considerably more diverse microbial composition within the biofilms. A total of eight phyla were recovered in this case, three of which were major groups: the Firmicutes (43.9%), the Proteobacteria (28.6%), and the Bacteroidetes (17.6%). The remaining five phyla were minor groups: the Planctomycetes (4.4%), the Chlorobi (2.2%), the Actinobacteria (1.1%), the Nitrospirae (1.1%), and the Verrucomicrobia (1.1%). The two most abundant genera detected were the endospore-forming bacteria (31.8%), Clostridium and Bacillus, both of which are members of the Firmicutes phylum. This finding indicates that these endospore-forming bacteria successfully colonized and dominated the RABC process biofilms. Many of the colonies or clones recovered from the biofilms evidenced significantly high homology in the 16S rDNA sequences of bacteria stored in databases associated with advanced wastewater treatment capabilities, including nitrification and denitrification, phosphorus accumulation, the removal of volatile odors, and the removal of chlorohydrocarbons or heavy metals. The microbial community structures observed in the biofilms were found to correlate nicely with the enhanced performance of advanced wastewater treatment protocols.

• Journal of Microbiology
• /
• v.43 no.4
• /
• pp.345-353
• /
• 2005

The complex ecosystem of intestinal micro flora is estimated to harbor approximately 400 different microbial species, mostly bacteria. However, studies on bacterial colonization have mostly been based on culturing methods, which only detect a small fraction of the whole microbiotic ecosystem of the gut. To clarify the initial acquisition and subsequent colonization of bacteria in an infant within the few days after birth, phylogenetic analysis was performed using 16S rDNA sequences from the DNA iso-lated from feces on the 1st, 3rd, and 6th day. 16S rDNA libraries were constructed with the amplicons of PCR conditions at 30 cycles and $50^{\circ}C$ annealing temperature. Nine independent libraries were produced by the application of three sets of primers (set A, set B, and set C) combined with three fecal samples for day 1, day 3, and day 6 of life. Approximately 220 clones ($76.7\%$) of all 325 isolated clones were characterized as known species, while other 105 clones ($32.3\%$) were characterized as unknown species. The library clone with set A universal primers amplifying 350 bp displayed increased diversity by days. Thus, set A primers were better suited for this type of molecular ecological analysis. On the first day of the life of the infant, Enterobacter, Lactococcus lactis, Leuconostoc citreum, and Streptococcus mitis were present. The largest taxonomic group was L. lactis. On the third day of the life of the infant, Enterobacter, Enterococcus faecalis, Escherichia coli, S. mitis, and Streptococcus salivarius were present. On the sixth day of the life of the infant, Citrobacter, Clostridium difficile, Enterobacter sp., Enterobacter cloacae, and E. coli were present. The largest taxonomic group was E. coli. These results showed that microbiotic diversity changes very rapidly in the few days after birth, and the acquisition of unculturable bacteria expanded rapidly after the third day.