OBJECTIVETo develop a resin composite incorporated with nano-antibacterial inorganic filler containing long-chain alkyl quaternary ammonium salt, and to measure its effect on human dental plaque microcosm biofilm.

METHODSA novel nano-antibacterial inorganic filler containing long-chain alkyl quaternary ammonium salt was synthesized according to methods introduced in previous research. Samples of the novel nano-antibacterial inorganic fillers were modified by a coupling agent and then added into resin composite at 0%, 5%, 10%, 15% or 20% mass fractions; 0% composite was used as control. A flexural test was used to measure resin composite mechanical properties. Results showed that a dental plaque microcosm biofilm model with human saliva as inoculum was formed. Colony-forming unit (CFU) counts, lactic acid production, and live/dead assay of biofilm on the resin composite were calculated to test the effect of the resin composite on human dental plaque microcosm biofilm.

RESULTSThe incorporation of nano-antibacterial inorganic fillers with as much as 15% concentration into the resin composite showed no adverse effect on the mechanical properties of the resin composite (P > 0.05). Resin composite containing 5% or more nano-antibacterial inorganic fillers significantly inhibited the metabolic activity of dental plaque microcosm biofilm, suggesting its strong antibacterial potency (P < 0.05).

CONCLUSIONThis novel resin composite exhibited a strong antibacterial property upon the addition of up to 5% nano-antibacterial inorganic fillers, thereby leading to effective caries inhibition in dental application.

Anti-Bacterial Agents ; pharmacology ; Biofilms ; drug effects ; Composite Resins ; chemistry ; Dental Caries ; prevention & control ; Dental Plaque ; Humans ; Lactic Acid ; Quaternary Ammonium Compounds ; pharmacology ; Saliva

Ammonium perchlorate (AP), mainly used as solid propellants, was reported to interfere with homeostasis via competitive inhibition of iodide uptake. However, detailed mechanisms remain to be elucidated. In this study, AP was administered at 0, 130, 260 and 520 mg/kg every day to 24 male SD rats for 13 weeks. The concentrations of iodine in urine, serum thyroid hormones levels, total iodine, relative iodine and total protein, and malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT) activity in thyroid tissues were measured, respectively. Our results showed that high-dose perchlorate induced a significant increase in urinary iodine and serum thyroid stimulating hormone (TSH), with a decrease of total iodine and relative iodine content. Meanwhile, free thyroxine (FT4) was decreased and CAT activity was remarkably increased. Particularly, the CAT activity was increased in a dose-dependent manner. These results suggested that CAT might be enhanced to promote the synthesis of iodine, resulting in elevated urinary iodine level. Furthermore, these findings suggested that iodine in the urine and CAT activity in the thyroid might be used as biomarkers for exposure to AP, associated with thyroid hormone indicators such as TSH, FT4.
Analysis of Variance ; Animals ; Catalase ; metabolism ; Dose-Response Relationship, Drug ; Homeostasis ; drug effects ; Iodine ; metabolism ; urine ; Male ; Malondialdehyde ; metabolism ; Perchlorates ; pharmacology ; Quaternary Ammonium Compounds ; pharmacology ; Radioimmunoassay ; Rats, Sprague-Dawley ; Superoxide Dismutase ; metabolism ; Thyroid Gland ; metabolism ; Thyrotropin ; blood ; Thyroxine ; blood ; Triiodothyronine ; blood

Antibacterial adhesives are promising to inhibit biofilms and secondary caries. The objectives of this study were to synthesize and incorporate quaternary ammonium methacrylates into adhesives, and investigate the alkyl chain length effects on three-dimensional biofilms adherent on adhesives for the first time. Six quaternary ammonium methacrylates with chain lengths of 3, 6, 9, 12, 16 and 18 were synthesized and incorporated into Scotchbond Multi-Purpose. Streptococcus mutans bacteria were cultured on resin to form biofilms. Confocal laser scanning microscopy was used to measure biofilm thickness, live/dead volumes and live-bacteria percentage vs. distance from resin surface. Biofilm thickness was the greatest for Scotchbond control; it decreased with increasing chain length, reaching a minimum at chain length 16. Live-biofilm volume had a similar trend. Dead-biofilm volume increased with increasing chain length. The adhesive with chain length 9 had 37% live bacteria near resin surface, but close to 100% live bacteria in the biofilm top section. For chain length 16, there were nearly 0% live bacteria throughout the three-dimensional biofilm. In conclusion, strong antibacterial activity was achieved by adding quaternary ammonium into adhesive, with biofilm thickness and live-biofilm volume decreasing as chain length was increased from 3 to 16. Antibacterial adhesives typically only inhibited bacteria close to its surface; however, adhesive with chain length 16 had mostly dead bacteria in the entire three-dimensional biofilm. Antibacterial adhesive with chain length 16 is promising to inhibit biofilms at the margins and combat secondary caries.
Anti-Bacterial Agents ; pharmacology ; Biofilms ; Methacrylates ; pharmacology ; Microscopy, Confocal ; Quaternary Ammonium Compounds ; pharmacology

Natural toxic substances have a bitter taste and their ingestion sends signals to the brain leading to aversive oral sensations. In the present study, we investigated chronological changes in c-Fos immunoreactivity in the nucleus tractus solitarius (NTS) to study the bitter taste reaction time of neurons in the NTS. Equal volumes (0.5 mL) of denatonium benzoate (DB), a bitter tastant, or its vehicle (distilled water) were administered to rats intragastrically. The rats were sacrificed at 0, 0.5, 1, 2, 4, 8, or 16 h after treatment. In the vehicle-treated group, the number of c-Fos-positive nuclei started to increase 0.5 h after treatment and peaked 2 h after gavage. In contrast, the number of c-Fos-positive nuclei in the DB-treated group significantly increased 1 h after gavage. Thereafter, the number of c-Fos immunoreactive nuclei decreased over time. The number of c-Fos immunoreactive nuclei in the NTS was also increased in a dose-dependent manner 1 h after gavage. Subdiaphragmatic vagotomy significantly decreased DB-induced neuronal activation in the NTS. These results suggest that intragastric DB increases neuronal c-Fos expression in the NTS 1 h after gavage and this effect is mediated by vagal afferent fibers.
Adjuvants, Immunologic/pharmacology ; Afferent Pathways/physiology ; Animals ; Injections/veterinary ; Ligands ; Male ; Proto-Oncogene Proteins c-fos/*metabolism ; Quaternary Ammonium Compounds/*pharmacology ; Rats ; Rats, Sprague-Dawley ; Receptors, G-Protein-Coupled/*metabolism ; Solitary Nucleus/*physiology ; Vagus Nerve/*drug effects/*physiology

This paper is aimed to study the effects of nitrogen form on the growth and quality of Chrysanthemums morifolium at the same nitrogen level. In order to provide references for nutrition regulation of Ch. morifolium in field production, pot experiments were carried out in the greenhouse at experimental station of Nanjing Agricultural University. Five proportions of ammonium and nitrate nitrogen were set up and a randomized block design was applied four times repeatedly. The results showed that the growth and quality of Ch. morifolium were significantly influenced by the nitrogen form. The content of chlorophyll and photosynthesis rate were the highest at the NH4(+) -N /NO3(-) -N ratio of 25:75; The activities of NR in different parts of Ch. -morifolium reached the highest at the NH4(+) - N/NO3(-) -N ratio of 0: 100. The contents of nitrate nitrogen in the root and leaves reached the highest at the NH4(+) -N/NO3(-) -N ratio of 50:50. The activities of GS, GOGAT and the content of amylum increased with the ratio of NO3(-) -N decreasing and reached it's maximum at the NH4 + -N/NO3 - -N ratio of 100: 0. The content of ammonium nitrogen were the highest at the NH4 + -N /NO3 --N ratio of 75: 25, while the content of soluble sugar reached the highest at the NH4(+)-N/NO3(-) -N ratio of 25: 75. The content of flavones, chlorogenic acid and 3,5-O-dicoffeoylqunic acid were 57.2 mg x g(-1), 0.673% and 1.838% respectively, reaching the maximum at the NH4(+) -N /NO3(-) -N ratio of 25:75; The content of luteoloside increased with the ratio of NO3(-) -N increasing and reached it's maximum at the NH4(+) -N/NO3(-) -N ratio of 0: 100. The yield of Ch. morifolium reached it's maximum at the NH4(+) -N /NO3(-) -N ratio of 25:75. Nitrogen form has some remarkable influence on the nitrogen metabolism, photosynthesis and growth, Nitrogen form conducive to the growth and quality of Ch. morifolium at the NH4(+) -N /NO3(-) -N ratio of 25: 75.
Ammonium Compounds ; metabolism ; pharmacology ; Chlorophyll ; metabolism ; Chrysanthemum ; drug effects ; growth & development ; metabolism ; Flowers ; drug effects ; growth & development ; metabolism ; Glutamate Synthase ; metabolism ; Glutamate Synthase (NADH) ; metabolism ; Glutamate-Ammonia Ligase ; Nitrates ; metabolism ; pharmacology ; Nitrogen ; metabolism ; pharmacology ; Photosynthesis ; drug effects ; Plant Leaves ; drug effects ; growth & development ; metabolism ; Plant Proteins ; metabolism ; Plant Roots ; drug effects ; growth & development ; metabolism ; Plant Stems ; drug effects ; growth & development ; metabolism

Deiters' cells are the supporting cells in organ of Corti and are suggested to play an important role in biochemical and mechanical modulation of outer hair cells. We successfully isolated functionally different K+ currents from Deiters' cells of guinea pig using whole cell patch clamp technique. With high K+ pipette solution, depolarizing step pulses activated strongly outward rectifying currents which were dose-dependently blocked by clofilium, a class III anti-arrhythmic K+ channel blocker. The remaining outward current was transient in time course whereas the clofilium-sensitive outward current showed slow inactivation and delayed rectification. Addition of 5 mM tetraethylammonium (TEA) further blocked the remaining current leaving a very fast inactivating transient outward current. Therefore, at least three different types of K+ current were identified in Deiters' cells, such as fast activating and fast inactivating current, fast activating slow inactivating current, and very fast inactivating transient outward current. Physiological role of them needs to be established.
Animals ; Ear, Inner ; Guinea Pigs* ; Guinea* ; Hair ; Hearing ; Organ of Corti ; Pharmacology ; Potassium Channels ; Potassium* ; Quaternary Ammonium Compounds ; Tetraethylammonium

The goal of treatment of metabolic syndrome is the prevention of diabetes and cardiovascular events. A series of novel tetrahydrocoptisine quaternary ammonium compounds were prepared to evaluate their action of hypoglycemia and hypolipidemia for finding the therapeutic agents of metabolic syndrome. Starting from the coptisine hydrochloride (2), fifteen target compounds were synthesized by reduction and substitution of the 7-N position. All of the target compounds were characterized by 1H NMR and HR-MS. Their hypoglycemic activities were evaluated in HepG2 cell and hypolipidemic activities of compounds with better hypoglycemic activity were tested further in vivo. Results indicated that compounds 5, 7, 8 and 9 exhibited better hypoglycemic activities in vitro and compounds 5 and 8 exhibited good hypolipidemic activities in high-fat-diet (HFD) induced hyperlipidemia mice and (or) hamsters. However, the activity is not as good as simvastatin.
Animals ; Berberine Alkaloids ; chemical synthesis ; chemistry ; pharmacology ; Cholesterol ; blood ; Glucose ; metabolism ; Hep G2 Cells ; Humans ; Hyperlipidemias ; blood ; Hypoglycemic Agents ; chemical synthesis ; chemistry ; pharmacology ; Hypolipidemic Agents ; chemical synthesis ; chemistry ; pharmacology ; Mesocricetus ; Mice ; Molecular Structure ; Quaternary Ammonium Compounds ; chemical synthesis ; chemistry ; pharmacology ; Structure-Activity Relationship ; Triglycerides ; blood

OBJECTIVEThe effects of different nitrogen forms on the growth and photosynthetic characteristics of Prunella vulgaris were observed.

METHODWater culture experiments were carried out to observe the effects of NH4+: NO3- ratios(100:0, 75: 25, 50:50, 25:75, 0:100 in mmol x L(-1)) on the growth and photosynthetic characteristics of P. vulgaris.

RESULTThe leaf area, fresh biomass and P(n) of these cultivars increased with the increasing of NH4(+) -N: NO3(-) -N ratios, and they were found to be the highest in 25: 75 NH4(+) -N: NO3)-) -N. However, they decreased with the increasing NH4(+) -N: NO3(-) -N ratio further. P. vulgaris had a minimum leaf area, biomass, chlorophyll content and P(n) in pure ammonium group. The biggest chlorophyll and carotenoid contents were found in the ratios of NH4(+) -N to NO3(-) -N of 50: 50.

CONCLUSIONThe results indicated that properly increasing nitrate proportion could promote the growth and photosynthesis of P. vulgaris.

Biomass ; Chlorophyll ; Nitrogen ; chemistry ; metabolism ; pharmacology ; Photosynthesis ; drug effects ; Plant Leaves ; drug effects ; Prunella ; growth & development ; metabolism ; Quaternary Ammonium Compounds ; chemistry ; metabolism

Adrenergic beta-2 Receptor Agonists ; pharmacology ; Anti-Inflammatory Agents ; pharmacology ; Asthma ; drug therapy ; physiopathology ; Chloroquine ; pharmacology ; Humans ; Myocytes, Smooth Muscle ; cytology ; drug effects ; metabolism ; Quaternary Ammonium Compounds ; pharmacology ; Receptors, Adrenergic, beta-2 ; metabolism ; Receptors, G-Protein-Coupled ; agonists ; metabolism ; Receptors, Interleukin-4 ; antagonists & inhibitors ; metabolism ; Respiratory System ; drug effects ; metabolism ; physiopathology

An ammonium-tolerant mutant of Actinobacillus succinogenes, YZ25, was obtained in the medium containing 61-242 mmol/L NH4+ after DES mutagenesis. Succinic acid produced by the mutant YZ25 reached 32.68 g/L when the medium contains 50 g/L glucose and 121 mmol/L ammonium, which was increased by 180.5% compared with that of the parent strain. The effects of different ammonium salts on the growth of the mutant and its metabolic response to high ammonium concentrations were investigated. The results showed that low ammonium concentration could improve the specific growth rates of the mutants, while high ammonium concentration inhibited cell growth. The ammonia-nitrogen half-inhibition constants (Ki) for different ammonium salts were as follows: 215 mmol/L for (NH4)2SO4, 265 mmol/L for NH4HCO3, 235 mmol/L for NH4Cl, and 210 mmol/L for NH4NO3. The process of ammonium inhibition on the mutant YZ25 was investigated in 3.0 L stirred fermenter. When NH4OH was used to buffer the pH, cell growth was not inhibited. However, production of succinic acid and consumption of glucose gradually decreased when cells entered the stationary phase, and the glucose could not be utilized completely at the end of fermentation. The possible ammonium inhibition mechanism was discussed based on the metabolic pathway of A. succinogenes.
Actinobacillus ; genetics ; growth & development ; metabolism ; Bioreactors ; Drug Tolerance ; Fermentation ; Industrial Microbiology ; Mutation ; Quaternary Ammonium Compounds ; metabolism ; pharmacology ; Succinic Acid ; metabolism