• Membrane and Water Treatment
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• v.9 no.3
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• pp.195-203
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• 2018

N-acetylcysteine (NAC) has been widely used as an initial mucolytic agent and is generally used as an antioxidant to help alleviate various inflammatory symptoms. NAC reduces bacterial extracellular polymeric substances (EPS) production, bacterial adhesion to the surface and strength of mature biofilm. The efficacy has been shown to inhibit proliferation of gram-positive and gram-negative bacteria. In membrane bioreactor (MBR) processes, which contain a variety of gram negative bacteria, biofilm formation has become a serious problem in stable operation. In this study, use of NAC as an inhibitor of biofilm contamination was investigated using the center for disease control (CDC) reactors with MBR sludge. Biomass reduction was confirmed with CLSM images of membrane surfaces by addition of NAC, which was more efficient as the concentration of NAC was increased to 1.5 mg/mL. NAC addition also showed decreases in EPS concentrations of the preformed biofilm, indicating that NAC was able to degrade EPS in the mature biofilm. NAC addition was also effective to inhibit biofilm formation by MBR sludge, which consisted of various microorganisms in consortia.

• Journal of Life Science
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• v.18 no.11
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• pp.1485-1492
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• 2008

Prostaglandin $A_2$ ($PGA_2$), one of cyclopentenone PGs, induced both apoptosis and heme oxygenase (HO)-1 expression in U2OS cells. $PGA_2$-induced apoptosis was not perturbed by either over-expression or knock-down of HO-1, whereas $H_2O_2$-induced cell death was inversely modulated by the expression level of HO-1. In addition, N-acetyl-L-cysteine (NAC), a thiol antioxidant, blocked both apoptosis and HO-1 expression induced by $PGA_2$. But, non-thiol antioxidants like butylated hydorxyanisole (BHA) and ascorbic acid did not block either apoptosis or HO-1-induction. Taken together, these results suggest that $PGA_2$ induces both apoptosis and HO-1 expression, which are critically related to the thiol- reactivity of $PGA_2$, but not oxidative stress, and HO-1 expression may be independent or functionally located downstream of apoptosis by $PGA_2$ without contribution to apoptosis progression.

• Journal of Life Science
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• v.23 no.5
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• pp.622-628
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• 2013

Diallyl trisulfide (DATS), one of the major organosulfur components of garlic (Allium sativum), has various biological effects such as anti-microbial and anti-cancer activities. However, the molecular mechanisms of growth inhibition related to cell cycle arrest are poorly understood. In this study, we investigated the effects of DATS on cell cycle progression in U937 human leukemia cells. Treatment with DATS in U937 cells resulted in inhibition of cell viability through G2/M arrest and apoptosis. DATS-induced G2/M arrest was associated with up-regulation of cyclin B1 and cyclin-dependent kinase 1 (CDK1). DATS also significantly increased levels of phospho-histone H3, which is a mitosis-specific marker, indicating that DATS induced mitotic arrest but not G2 arrest in U937 cells. DATS treatment also generated the reactive oxygen species (ROS) in U937 cells; however, pretreatment with N-acetyl-l-cysteine (NAC), a ROS scavenger, significantly attenuated DATS-induced mitotic arrest and apoptosis. Taken together, our data indicate that DATS exhibits anti-cancer effects through mitotic arrest and apoptosis in a ROS-dependent manner.

• Korean Journal of Clinical Laboratory Science
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• v.51 no.2
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• pp.171-176
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• 2019

A comparative study between commercially available mycobacteria growth indicator tubes (MGIT) in the BACTEC MGIT 960 System and the conventional Ogawa media was carried out to assess the effectiveness of the re-decontaminating process for the recovery of mycobacteria. Processed specimens with 5% sodium hydroxide and 0.5% N-acetyl-L-cysteine were inoculated into MGIT and Ogawa media. The acid fast bacilli (AFB) recovered from the cultures were identified using a mycobacterium tuberculosis (TB) antigen kit. If contaminants were observed in the MGIT tubes within five days, a decontaminating process was repeated. A total of 1,190 out of 4,790 (24.8%) specimens showed positive results using the BACTEC MGIT 960 system. Among them, 278 specimens were reprocessed. When the MGIT and Ogawa results were compared, it showed discordant results (weighted kappa value: 0.283). One TB and 10 nontuberculous mycobacteria (NTM) were newly detected in MGIT only. The likely benefit of the re-decontaminating process is the detection of additional mycobacteria that could not be detected without a re-decontaminating process despite being small in number. In addition to the combination of MGIT and Ogawa, the re-decontaminating process is recommended in the case of contaminations to recover mycobacteria.

• Clinical and Experimental Reproductive Medicine
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• v.49 no.2
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• pp.117-126
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• 2022

Objective: This study examined whether the addition of triple antioxidants (3A)-10 µM acetyl-L-carnitine, 10 µM N-acetyl-L-cysteine, and 5 µM α-lipoic acid-in freezing-thawing medium during human sperm cryopreservation using the sucrose vitrification (SuV) and liquid nitrogen vapor (Vapor) techniques could improve post-thaw survival of spermatozoa. Methods: We analyzed 30 samples from healthy human sperm donors. Each sample was allocated into one of five groups: fresh control, SuV, SuV+3A, Vapor, and Vapor+3A. The sperm motility, morphology, viability, intracellular and extracellular reactive oxygen species (ROS) levels, and sperm DNA fragmentation (SDF) were evaluated. Results: The cryopreserved spermatozoa had significantly reduced percentages of motility (p<0.05) and viability (p<0.05). Antioxidant supplementation non-significantly improved these parameters (p>0.05). No significant differences were found in sperm morphology between the fresh and frozen-thawed groups (p>0.05). After freezing, the extracellular ROS levels in the frozen-thawed groups were significantly higher (p<0.05) than in the fresh group. However, we did not find any differences in intracellular ROS parameters among these groups (p>0.05). The SDF was higher in the SuV and Vapor groups than in the fresh group, but without statistical significance (p=0.075 and p=0.077, respectively). Conclusion: Cryopreservation had detrimental effects on sperm motility, viability, and extracellular ROS levels, without changing the morphology or intracellular ROS levels. Antioxidant supplementation was slightly effective in preventing SDF in frozen-thawed spermatozoa.

• Korean Journal of Microbiology
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• v.45 no.3
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• pp.281-285
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• 2009

In this study, we compared the BacT/Alert liquid culture system with Ogawa and $L\ddot{o}wenstein$-Jensen (L-J) media for sputum culture and drug susceptibility test (DST) of Mycobacterium tuberculosis. Rapid liquid culture systems have been widely employed both for primary cultures of M. tuberculosis from clinical specimens and for drug susceptibility test because of its greater sensitivity and faster turn-around time than the conventional egg-based culture methods (Ogawa, $L\ddot{o}wenstein$-Jensen media). Sputum specimens were decontaminated with N-acetyl-L-cysteine (NALC)-4% NaOH and inoculated into the BacT/Alert culture bottles and Ogawa media. 95 from among 135 sputa were smear-positive, 97 (71.9%) were culture-positive by the BacT/Alert culture system, while 89 (65.9%) were positive by Ogawa media. The mean time to culture-positive by the BacT/Alert process system was about 11.3 days, which was significantly shorter than that by Ogawa media (22.4 days). Of 32 M. tuberculosis cultures examined for drug sensitivity, the concordant rate between the two methods (BacT/ Alert liquid culture system, $L\ddot{o}wenstein$-Jensen media) ranged from 87.5% for isoniazid and 90.6% for rifampicin.

• BMB Reports
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• v.44 no.3
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• pp.165-169
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• 2011

Excess free iron generates oxidative stress that may contribute to the pathogenesis of various causes of neurodegenerative diseases. In this study, we assessed the modification of ferritin induced by $H_2O_2$. When ferritin was incubated with $H_2O_2$, the degradation of ferritin L-chain increased with the $H_2O_2$ concentration whereas ferritin H-chain was remained. Free radical scavengers, azide, thiourea, and N-acetyl-$_L$-cysteine suppressed the $H_2O_2$-mediated ferritin modification. The iron specific chelator, deferoxamine, effectively prevented $H_2O_2$-mediated ferritin degradation in modified ferritin. The release of iron ions from ferritin was increased in $H_2O_2$ concentration-dependent manner. The present results suggest that free radicals may play a role in the modification and iron releasing of ferritin by $H_2O_2$. It is assumed that oxidative damage of ferritin by $H_2O_2$ may induce the increase of iron content in cells and subsequently lead to the deleterious condition.

• Toxicological Research
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• v.23 no.3
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• pp.215-221
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• 2007

Although sanguinarine, a benzophenanthridine alkaloid, possesses anti-cancer properties against several cancer cell lines, the molecular mechanisms by which it inhibits cell growth and induces apoptosis have not been clearly understood. In order to further explore the critical events leading to apoptosis in sanguinarine-treated MCF-7 human breast carcinoma cells, the following effects of sanguinarine on components of the mitochondrial apoptotic pathway were examined: generation of reactive oxygen species (ROS), alteration of the mitochondrial membrane potential (MMP), and the expression changes of Bcl-2 family proteins. We show that sanguinarine-induced apoptosis is accompanied by the generation of intracellular ROS and disruption of MMP as well as an increase in pro-apoptotic Bax expression and a decrease of anti-apoptotic Bcl-2 and Bcl-xL expression. The quenching of ROS generation with N-acetyl-L-cysteine, the ROS scavenger, protected the sanguinarine-elicited ROS generation, mitochondrial dysfunction, modulation of Bcl-2 family proteins, and apoptosis. Based on these results, we propose that the cellular ROS generation plays a pivotal role in the initiation of sanguinarine-triggered apoptotic death.

• Journal of Ginseng Research
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• v.39 no.2
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• pp.169-177
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• 2015

Background: Ginsenoside Rd (GSRd), one of the most abundant ingredients of Panax ginseng, protects the heart via multiple mechanisms including the inhibition of $Ca^{2+}$ influx.We intended to explore the effects of GSRd on L-type $Ca^{2+}$ current ($I_{Ca,L}$) and define the mechanism of the suppression of $I_{Ca,L}$ by GSRd. Methods: Perforated-patch recording and whole-cell voltage clamp techniques were applied in isolated rat ventricular myocytes. Results: (1) GSRd reduced $I_{Ca,L}$ peak amplitude in a concentration-dependent manner [half-maximal inhibitory concentration $(IC_{50})=32.4{\pm}7.1{\mu}mol/L$] and up-shifted the current-voltage (I-V) curve. (2) GSRd ($30{\mu}mol/L$) significantly changed the steady-state activation curve of $I_{Ca,L}$ ($V_{0.5}:-19.12{\pm}0.68$ vs. $-6.26{\pm}0.38mV$; n = 5, p < 0.05) and slowed down the recovery of $I_{Ca,L}$ from inactivation [the time content (${\zeta}$) from 91 ms to 136 ms, n = 5, p < 0.01]. (3) A more significant inhibitive effect of GSRd ($100{\mu}mol/L$) was identified in perforated-patch recording when compared with whole-cell recording [$65.7{\pm}3.2%$ (n = 10) vs. $31.4{\pm}5.2%$ (n = 5), p < 0.01]. (4) Pertussis toxin ($G_i$ protein inhibitor) completely abolished the $I_{Ca,L}$ inhibition induced by GSRd. There was a significant difference in inhibition potency between the two cyclic adenosine monophosphate elevating agents (isoprenaline and forskolin) prestimulation [$55{\pm}7.8%$ (n = 5) vs. $17.2{\pm}3.5%$ (n = 5), p < 0.01]. (5) 1H-[1,2,4]Oxadiazolo[4,3-a]-quinoxalin-1-one (a guanylate cyclase inhibitor) and N-acetyl-$\small{L}$-cysteine (a nitric oxide scavenger) partly recovered the $I_{Ca,L}$ inhibition induced by GSRd. (6) Phorbol-12-myristate-13-acetate (a protein kinase C activator) and GF109203X (a protein kinase C inhibitor) did not contribute to the inhibition of GSRd. Conclusion: These findings suggest that GSRd could inhibit $I_{Ca,L}$ through pertussis toxin-sensitive G protein ($G_i$) and a nitric oxide-cyclic guanosine monophosphate-dependent mechanism.

• Archives of Pharmacal Research
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• v.29 no.2
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• pp.145-151
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• 2006

We investigated the effects of Ginsenoside $R_e$ on human sperm motility in fertile and asthenozoospermic infertile individuals in vitro and the mechanism by which the Ginsenosides play their roles. The semen samples were obtained from 10 fertile volunteers and 10 asthenozoospermic infertile patients. Spermatozoa were separated by Percoll and incubated with 0, 1, 10 or $100\;{\mu}M$ of Ginsenoside $R_e$. Total sperm motility and progressive motility were measured by computer-aided sperm analyzer (CASA). Nitric oxide synthase (NOS) activity was determined by the $^{3}H$-arginine to $^{3}H$-citrulline conversion assay, and the NOS protein was examined by the Western blot analysis. The production of sperm nitric oxide (NO) was detected using the Griess reaction. The results showed that Ginsenoside $R_e$ significantly enhanced both fertile and infertile sperm motility, NOS activity and NO production in a concentration-dependent manner. Sodium nitroprusside (SNP, 100 nM), a NO donor, mimicked the effects of Ginsenoside $R_e$. And pretreatment with a NOS inhibitor $N^{w}$-Nitro-L-arginine methyl ester (L-NAME, $100\;{\mu}M$) or a NO scavenger N-Acetyl-L-cysteine (LNAC, 1 mM) completely blocked the effects of Ginsenoside $R_e$. Data suggested that Ginsenoside $R_e$ is beneficial to sperm motility, and that induction of NOS to increase NO production may be involved in this benefit.