• Asian-Australasian Journal of Animal Sciences
• /
• v.4 no.4
• /
• pp.369-375
• /
• 1991

A series of in vitro incubation studies with washed rumen bacteria were conducted to determine the influence of incubation time and concentrations of peptides, alanine, ammonia nitrogen and carbohydrate on the rate of peptide disappearance and on bacterial growth. Disappearance rate of tri-alanine (ala3) under various conditions was between 30.6 and $58.2mg\;hr^-$ per gram bacterial dry matter. Ala3 was removed from the incubation medium in an almost linear fashion as incubation time and ala3 concentration was increased. Washed rumen bacteria utilized ala3 faster than di-l-alanine (ala2) at all concentrations. Adding 9mM carbohydrate significantly increased ala3 disappearance, but level of ammonia nitrogen had no influence on ala3 disappearance. The presence of alanine in the medium significantly lowered ala3 utilization by rumen bacteria. Bacterial dry matter and nitrogen growth yield were not influenced by alanine and peptides when incubation medium already contained a sufficient level of ammonia nitrogen. Increased ammonia nitrogen in the presence of ala3 did not stimulate bacterial growth. Carbohydrate significantly increased bacterial dry matter and nitrogen growth as expected. Results indicate that the rate of peptide utilization by rumen bacteria may be altered by type and concentration of peptides, and energy supply, and this may be mediated through changes in numbers and type of bacteria.

• Asian-Australasian Journal of Animal Sciences
• /
• v.5 no.3
• /
• pp.559-561
• /
• 1992

Three strains each of L. bulgaricus and S. thermophilus isolated from indigenous dahi were examined for their rate of acid production and corresponding pH values in skim milk medium incubated at $40^{\circ}C$. No significant increase in titrable acidity or decrease in pH were recorded from initial period up to 2nd hour in both the strains. Following this period, however, there was a continuous increase in titrable acidity and a decrease in pH value in the milk for all the tested strains. Further it was observed that there was a variation among these strains for their acid production rate. High rate of acid production was recorded for the L. bulgaricus as compared to S. thermophilus. The results further, suggested that efforts should be made to select a proper pair of L. bulgaricus and S. thermophilus according to their rate of acid production, at a particular temperature in order to produce a good quality product.

• 한국생물공학회:학술대회논문집
• /
• 2005.10a
• /
• pp.348-352
• /
• 2005

In this study, fermentation using a rotary biofilm contactor was conducted to improve bacterial cellulose production. We investigated the optimal fermentation conditions by using a newly isolated Gluconacetobacter sp. RKY5 in the rotary biofilm contactor. The optimal total area of discs was found to be 1,769 $cm^2$ at which bacterial cellulose and cell concentration was obtained to 5.52 g/L and 4.98 g/L, respectively. In case of aeration experiment, when the aeration rate was 1.25 vvm, the maximal bacterial cellulose (5.67 g/L) was obtained and cell concentration was 5.25 g/L.

• The Plant Pathology Journal
• /
• v.32 no.6
• /
• pp.537-544
• /
• 2016

We developed a model, termed D-PSA-K, to estimate the accumulated potential damage on kiwifruit canes caused by bacterial canker during the growing and overwintering seasons. The model consisted of three parts including estimation of the amount of necrotic lesion in a non-frozen environment, the rate of necrosis increase in a freezing environment during the overwintering season, and the amount of necrotic lesion on kiwifruit canes caused by bacterial canker during the overwintering and growing seasons. We evaluated the model's accuracy by comparing the observed maximum disease incidence on kiwifruit canes against the damage estimated using weather and disease data collected at Wando during 1994-1997 and at Seogwipo during 2014-2015. For the Hayward cultivar, D-PSA-K estimated the accumulated damage as approximately nine times the observed maximum disease incidence. For the Hort16A cultivar, the accumulated damage estimated by D-PSA-K was high when the observed disease incidence was high. D-PSA-K could assist kiwifruit growers in selecting optimal sites for kiwifruit cultivation and establishing improved production plans by predicting the loss in kiwifruit production due to bacterial canker, using past weather or future climate change data.

• Journal of Microbiology and Biotechnology
• /
• v.21 no.7
• /
• pp.739-745
• /
• 2011

During the production of grape wine, the formation of thick leathery pellicle/bacterial cellulose (BC) at the airliquid interface was due to the bacterium, which was isolated and identified as Gluconacetobacter hansenii UAC09. Cultural conditions for bacterial cellulose production from G. hansenii UAC09 were optimized by central composite rotatable experimental design. To economize the BC production, coffee cherry husk (CCH) extract and corn steep liquor (CSL) were used as less expensive sources of carbon and nitrogen, respectively. CCH and CSL are byproducts from the coffee processing and starch processing industry, respectively. The interactions between pH (4.5-8.5), CSL (2-10%), alcohol (0.5-2%), acetic acid (0.5-2%), and water dilution rate to CCH ratio (1:1 to 1:5) were studied using response surface methodology. The optimum conditions for maximum BC production were pH (6.64), CSL (10%), alcohol (0.5%), acetic acid (1.13%), and water to CCH ratio (1:1). After 2 weeks of fermentation, the amount of BC produced was 6.24 g/l. This yield was comparable to the predicted value of 6.09 g/l. This is the first report on the optimization of the fermentation medium by RSM using CCH extract as the carbon source for BC production by G. hansenii UAC09.

• The Korean Journal of Mycology
• /
• v.41 no.2
• /
• pp.118-126
• /
• 2013

The experiment was carried out to analyze the inhibition effect of plant pathogenic fungi and growth promotion activity induced by the bacterial strains isolated from peatmoss. Among the isolated bacterial strains, B10-2, B10-4, B10-5 and B10-6 which showed more than 30% inhibition rate against Botrytis cinerea and Rhizoctonia solani in vitro, were further analyzed in the greenhouse for the growth promotion activity on lettuce (Lactuca sativa), pak-choi (Brassica compestris L. ssp. chinensis) and Chinese cabbage (Brassica campestris L. ssp. pekinensis). The results showed the treatment of B10-4 on lettuce showed the highest growth promotion activity with the leaf area ($169.17cm^2$), fresh weight (leaf: 40.29 g, root: 8.80 g)and dry weight (leaf: 11.24 g, root: 4.17 g), which was about two folds as compared to control. On pak-choi, the growth promotion rate was the highest with the leaf area of $112.87cm^2$, leaf fresh weight of 60.70 g, root fresh weight of 3.37 g, leaf dry weight of 14.34 g, and root dry weight of 1.90 g. As a result of treatment of B10-13 on chinese cabbage, the growth promotion rate was the highest with the leaf area ($293.56cm^2$), fresh weight (leaf: 113.67 g, root: 2.40 g) and dry weight (leaf: 6.03 g, root: 0.53 g). The production of Indole Acetic Acid (IAA) and Indole-3-Butylic Acid (IBA) were also analyzed in these bacterial isolates. The IAA and IBA analyses were carried out in all bacterial isolates each day within the 5 days of incubation period. The highest production of IAA was observed with $112.57{\mu}g/mg$ protein in B10-4 after 3 days of incubation and IBA production was the highest in B10-2 with $58.71{\mu}g/mg$ protein after 2 days of incubation. Also, phosphate solubilizing activity was expressed significantly in B10-13 in comparison to that of other bacterial isolates. Bacterial identification showed that B10-2 was Bacillaceae bacterium and B10-5 was Bacillus cereus, B10-4 and B10-6 were Bacillus sp. and B-13 was Staphylococcus sp. by ITS sequence.

• Asian-Australasian Journal of Animal Sciences
• /
• v.7 no.1
• /
• pp.91-96
• /
• 1994

This study was conducted to determine the effect of inorganic selenium (Se) sources on rumen bacterial yield, ruminal volatile fatty acid (VFA) production and total tract digestion of timothy hay (Phlewm pratense L.) in Japanese Corriedale wethers. A $3{\times}3$ Latin square design was used with three wethers, three periods and three treatments. In each period, there was 7 d dietary adjustment followed by 5 d total collection of urine and feces. Ruminal fluid samples were obtained at 0, 1, 3, 5 and 7 h postprandially on the final day of the collection period. The three dietary treatments were: (1) without Se supplementation (control); (2) with Se supplementation as sodium selenate; and (3) sodium selenite at a rate 0.2 mg Se/kg dietary DM. The basal diet was timothy hay fed at 2% of body weight/d. Results indicated that there was slight decrease in rumen bacterial yield of animal supplement with inorganic Se, however, differences over the control were insignificant. It was found that Se content of ruminal fluid was negatively correlated (p < 0.05) to rumen bacterial yield. The various VFA contents and acetate and propionate ratio of the different ruminal fluid samples were insignificant across treatment means and the same manner was observed to the different digestibilities (DM, OM, CP, NDF, ADF and NDS). This study concludes that Se supplementation at 0.2 mg Se/kg dietary DM either from sodium selenate or sodium selenite could not significantly influence rumen bacterial functions.

• Textile Coloration and Finishing
• /
• v.33 no.4
• /
• pp.338-347
• /
• 2021

In the case of occlusive dressings currently used in dressings for burn treatment, it is impossible to confirm the replacement time, so replacement is delayed, resulting in additional infection. To solve this problem, liposomes capable of bacterial sensing were prepared using 5(6)-Carboxyfluorescein, Phosphatidylcholine, 1,2-Dipalmitoyl-sn-glycero-3-phosphocholine, Cholesterol, and 10,12-Tricosadiynoic acid. In this study, evaluation of changes in drug encapsulation rate in liposomes according to changes in three types of phosphatidylcholine phospholipids during liposome production, high-performance phosphatidylcholine phospholipids selected through vesicle size analysis, low and high temperature stability evaluation, bacterial sensitization ability evaluation, animals cell responses were assessed.

• Transactions of the Korean hydrogen and new energy society
• /
• v.17 no.4
• /
• pp.379-388
• /
• 2006

Two mesophilic trickling bed bioreactors filled with two different types of media, hydrophilic- and hydrophobic-cubes, were designed and conducted for hydrogen production under the anaerobic fermentation of sucrose. Each bioreactor consisted of the column packed with polymeric cubes and inoculated with heat-treated sludge obtained from anaerobic digestion tank. A defined medium containing sucrose was fed by the different hydraulic retention time(HRT), and recycle rate. Hydrogen concentrations in gas-phase were constant, averaging 40% of biogas throughout the operation. Hydrogen production rate was increased till $10.5\;L{\cdot}h^{-1}{\cdot}L^{-1}$ of bioreactor when influent sucrose concentrations and recycle rates were varied. At the same time, the hydrogen production rate with hydrophobic media application was higher than its hydrophilic media application. No methane was detected when the reactor was under a normal operation. The major fermentation by-products in the liquid effluent of the both trickling biofilters were acetate, butyrate and lactate. In order to run in the long term operation of both reactor filled with hydrophilic and hydrophobic media, biofilm accumulation on hydrophilic media and biogas produced should be controlled through some process such as periodical backwashing or gas-purging. Four sample were collected from each reactor on the opposite hydrogen production rate, and their bacterial communities were compared by terminal restriction fragment length polymorphism (T-RFLP) analysis of PCR products generated using bacterial 16s rRNA gene primers (8f and 926r). It was expressed a marked difference in bacterial communities of both reactors. The trickling bed bioreactor with hydrophobic media demonstrates the feasibility of the process to produce hydrogen gas. A likely application of this reactor technology can be hydrogen gas recovery from pre-treatment of high carbohydrate-containing wastewaters.

• The Korean Journal of Physiology and Pharmacology
• /
• v.2 no.3
• /
• pp.331-343
• /
• 1998

Sublethal dose of bacterial lipopolysaccharide (LPS) would induce protection against cardiac ischemic/reperfusion (I/R) injury. This study examines the following areas: 1) the temporal induction of the cardio-protection produced by LPS; and 2) the relations between a degree of protection and the myocardial prostacyclin ($PGI_2$) production. Rats were administered LPS (2 mg/kg, i.v.), and hearts were removed 1, 4, 8, 14, 24, 48, 72,and 96 h later. Using Langendorff apparatus, haemodynamic differences during 25 min of global ischemia/30 min reperfusion were investigated. The concentration of $PGI_2$ in aliquots of the coronary effluent was determined by radioimmunoassay as its stable hydrolysis product $6-keto-PGF1_{\alpha}$ and lactate dehydrogenase release were measured as an indicative of cellular injury. LPS-induced cardiac protection against I/R injury appeared 4 h after LPS treatment and remained until 96 h after treatment. $PGI_2$ release increased 2-3 fold at the beginning of reperfusion compared to basal level except in hearts treated with LPS for 48 and 72 h. In hearts removed 48 and 72 h after LPS treatment, basal $PGI_2$ was increased. To determine the enzymatic step in relation to LPS-induced basal $PGI_2$ production, we examined prostaglandin H synthase (PGHS) protein expression, a rate limiting enzyme of prostaglandin production, by using Western blot analysis. LPS increased PGHS protein expression in hearts at 24, 48, 72, 96 h after LPS treatment. Induction of PGHS expression appeared in both isotypes of PGHS, a constitutive PGHS-1 and an inducible PGHS-2. To identify the correlationship between $PGI_2$ production and the cardioprotective effect against I/R injury, indomethacin was administered in vivo or in vitro. Indomethacin did not inhibit LPS-induced cardioprotection, which was not affected by the duration of LPS treatment. Taken together, our results suggest that $PGI_2$ might not be the major endogenous mediator of LPS-induced cardioprotection.