Number Of Bacterial Cells Research Articles

Isolasi dan Identifikasi Bakteri Pelarut Fosfat pada Tanah Ultisol di Kecamatan Rumbai, Pekanbaru

<p class="Abstract">Phosphate-solubilizing bacterial can fulfill the low available of soluble P on Ultisol. This research aimed to study on the quantity of the population bacteria and identify phosphate-solubilizing bacteria on Ultisol from Rumbai District, Pekanbaru. The research method used was descriptive method. Soil sample was collected from teak plantations of PT. Air Jernih, Sub district of Rumbai Pesisir, Pekanbaru and identification of phosphate-solubilizing bacteria was conducted in Laboratory of Pathology, Entomology and Microbiology, Faculty of Agriculture and Animal Husbandry, Universitas Sultan Syarif Kasim State Islamic, Riau from May-September 2017. The observed parameters were bacterial cell numbers, phosphate solubilization index, microscopic and biochemical characteristics. Four isolates were obtained with cell numbers ranging from 4.2 x 10<sup>5</sup> – 7.1 x 10<sup>5</sup> CFU/g of soil. All isolates showed the ability to dissolve phosphate with phosphate solubilization index ranging from 1.16 – 1.57. The four isolates were identified as <em>Klebsiella </em>(IBJ1 and IBJ2), and <em>Acinetobacter </em>(IBJ3 and IBJ4).</p>

Bacterial Surface Colonization of Sputter-Coated Platinum Films.

Due to its biocompatibility and advantageous electrochemical properties, platinum is commonly used in the design of biomedical devices, e.g., surgical instruments, as well as electro-medical or orthopedic implants. This article verifies the hypothesis that a thin layer of sputter-coated platinum may possess antibacterial effects. The purpose of this research was to investigate the adhesion and growth ability of a model strain of Gram-negative bacteria, Escherichia coli, on a surface of a platinum-coated glass slide. Although some previous literature reports suggests that a thin layer of platinum would inhibit the formation of bacterial biofilm, the results of this study suggest otherwise. The decrease in the number of bacterial cells attached to the platinum-coated glass, which was observed within first three hours of culturing, was found to be a short-time effect, vanishing after 24 h. Consequently, it was shown that a thin layer of sputter-coated platinum did not exhibit any antibacterial effect. For this reason, this study indicates an urgent need for the development of new methods of surface modification that could reduce bacterial surface colonization of platinum-based biomedical devices.

국내 작물의 배양 가능한 미생물 확인 및 유용 미생물 분리 방법 연구

In this study, we investigated culturable bacterial abundance in various crops. Total culturable aerobic bacteria in tomato plants were enumerated on NA and it showed that the amounts of viable bacterial cells were changed among the different parts of the plants (roots, stems, and fruits), ranging between log 1 and 4 per g sample. To investigate the bacterial abundance dynamics in different crops, culturable aerobic bacterial cell numbers were enumerated on NA and compared between the samples (tomato fruit, sesame leaf, and green onion) harvested freshly from one field trial (Yangsan, Korea). In this trial, the number of total culturable aerobic bacteria of the samples were 8 times higher in sesame leaves and green onions compared to the tomato fruits in the field. Interestingly, culturable aerobic bacteria on MRS were only found in sesame leaves, whereas lactic acid bacteria were not detected in tomato fruit and green onion samples in this field. We also found that the field location (Yangsan, Gangneung, or Busan) influenced the number of culturable aerobic bacteria on the surface of the crops. Tomato samples freshly harvested from the different field locations were tested and showed that the amounts of culturable aerobic bacteria on NA and MRS agar were significantly different based on the field locations of the samples. Finally, lactic acid bacteria were isolated from all the tomato and sesame leaf samples used in this study, showing 20 and 28 morphological diversity. With these isolates, we will be able to conduct further biological and functional investigation to develop a new probiotic strain originated from the crops in Korea.

Produksi Biolistrik menggunakan Microbial Fuel Cell (MFC) Lactobacillus bulgaricus dengan Substrat Limbah Tempe dan Tahu

The use of electricity in Indonesia with energy sources from fossils still dominates compared to other energy sources. Of the total power plant capacity in the country today, coal-fired steam power plants (PLTU) still dominate, namely 24,883 MW or 48% of the total domestic generating capacity of 52,231 MW. Fossil as a non-renewable fuel is produced continuously and will certainly run out. Development of renewable alternative energy is needed and the amount is not limited to being a renewable energy source. An alternative renewable energy source that has been developed to produce alternative electrical energy, one of which is a microbial fuel cell (MFC). This study aims to utilize Lactobacillus bulgaricus bacteria to metabolize waste water tofu and tempeh as a substrate in the MFC system to produce electrical energy. Research using tofu waste substrate has been carried out, but the use of tempe waste substrate has never been done, and the use of a mixture of waste substrate is not yet known. Microbial Fuel Cell (MFC) using L. bulgaricus in tofu waste produced a potential voltage with the highest yield of 282 mV and the number of bacterial cells reached 12.4 x 106 CFU / mL at the 5th hour incubation, whereas the mixture of tempeh and tofu waste produces a bioelectric potential of 274 mV at the 3rd hour incubation

Factors affecting the abundance and activity of the bacterioplankton in lowland forest springs in north-eastern Poland

The paper summarises the results of bacteriological and hydrochemical studies on the lowland springs in the big forest complex of the Podlasie region in NE Poland. In this area, 75 springs were investigated in the summer period of 2014 and 2015 to determine bacterial number, biomass and hydrolytic activity. All investigated objects were categorized by direct catchment land use and hydrobiological type. The number and biomass of bacteria in the water of the investigated springs is much smaller than in other types of surface water in lowland areas and ranges from 0.29 to 2.94 106 cells cm−3. The best reflection of the habitat quality within lowland groundwater outflows is their hydrobiological typology (helocrene, rheocrene and limnocrene). Despite differing development of spring niches, their hydrology, as well as the geological material and its graining cause unification of the bacterial numbers. The number of bacteria cells were correlated with the concentration of some nitrogen compounds (NH4+, NO2−), and the hydrolytic activity of bacteria with phosphorus compounds mainly dissolved phosphorus. The presence of dissolved organic carbon compounds turned out to be the most disturbing factor in the development of bacterioplankton. Concentrations of these parameters were found to be conditioned by the management of the direct outflow catchment. Furthermore in rheocrene springs, bacterial activity during hydrological stress is clearly lower, despite a large number of bacterial cells in the water (r=-0.38; p<0.005). Our results show that lowland springs are a very sensitive objects to changes in land use, which has a significant impact on water quality and thus the number and activity of bacteria.

A novel real-world ecotoxicological dataset of pelagic microbial community responses to wastewater

Real-world observational datasets that record and quantify pressure-stressor-response linkages between effluent discharges and natural aquatic systems are rare. With global wastewater volumes increasing at unprecedented rates, it is urgent that the present dataset is available to provide the necessary information about microbial community structure and functioning. Field studies were performed at two time-points in the Austral summer. Single-species and microbial community whole effluent toxicity (WET) testing was performed at a complete range of effluent concentrations and two salinities, with accompanying environmental data to provide new insights into nutrient and organic matter cycling, and to identify ecotoxicological tipping points. The two salinity regimes were chosen to investigate future scenarios based on a predicted salinity increase at the study site, typical of coastal regions with rising sea levels globally. Flow cytometry, amplicon sequencing of 16S and 18S rRNA genes and micro-fluidic quantitative polymerase-chain reactions (MFQPCR) were used to determine chlorophyll-a and total bacterial cell numbers and size, as well as taxonomic and functional diversity of pelagic microbial communities. This strong pilot dataset could be replicated in other regions globally and would be of high value to scientists and engineers to support the next advances in microbial ecotoxicology, environmental biomonitoring and estuarine water quality modelling.

Antibacterial activity and mechanism of Litsea cubeba essential oil against food contamination by Escherichia coli and Salmonella enterica

AbstractLitsea cubeba essential oil (LC‐EO) has been reported as antibacterial agents, but there are few studies about its possible antibacterial mechanism. The antibacterial activities and the underlying mechanisms of LC‐EO against Escherichia coli O157: H7 and Salmonella enterica were investigated. The results showed that the LC‐EO was more effective against gram‐negative bacteria. The inhibition zone for E. coli O157: H7 and S. enterica were 3.1 ± 0.8 and 4.5 ± 0.6 mm, respectively. The minimum inhibitory concentration of LC‐EO against both bacteria was 0.9 μg/ml, while the minimum bactericidal concentrations were 4.5 and 9 μg/ml. Gas chromatography–mass spectrometry analysis confirmed that citral (86.8%) was the main component of LC‐EO. The results of a time–kill analysis illustrated that treatment with LC‐EO led to a rapid decrease in viable bacterial cell number. The release of electrolytes and nucleic acids from the bacterial cells increased with the dose of LC‐EO. Propidium iodide uptake revealed that LC‐EO caused cell membrane damage. Scanning electron and transmission electron microscopy showed that LC‐EO caused damage to the cell walls and membranes, resulting in cell deformation, atrophy, and large central voids. Thus, LC‐EO may provide the basis for the development of new natural food preservatives.

YSMR: a video tracking and analysis program for bacterial motility

BackgroundMotility in bacteria forms the basis for taxis and is in some pathogenic bacteria important for virulence. Video tracking of motile bacteria allows the monitoring of bacterial swimming behaviour and taxis on the level of individual cells, which is a prerequisite to study the underlying molecular mechanisms.ResultsThe open-source python program YSMR (Your Software for Motility Recognition) was designed to simultaneously track a large number of bacterial cells on standard computers from video files in various formats. In order to cope with the high number of tracked objects, we use a simple detection and tracking approach based on grey-value and position, followed by stringent selection against suspicious data points. The generated data can be used for statistical analyses either directly with YSMR or with external programs.ConclusionIn contrast to existing video tracking software, which either requires expensive computer hardware or only tracks a limited number of bacteria for a few seconds, YSMR is an open-source program which allows the 2-D tracking of several hundred objects over at least 5 minutes on standard computer hardware.The code is freely available at https://github.com/schwanbeck/YSMR

THE USE OF CYTOLOGICAL STUDIES TO DETERMINE THE READINESS OF BURN WOUNDS FOR AUTODERMOPLASTY

Summary. For an objective assessment of the readiness of burn wounds for autodermoplasty, a cytological technique was used, which allowed to improve the healing of skin flaps, the number of surgical interventions and the treatment time of patients were reduced.&#x0D; Objective. To improve the results of skin grafting in connection with the use of an objective cytological method for studying the wound process, which allows you to determine the readiness of the wound bed for autodermoplasty.&#x0D; Materials and methods. In 2019, 29 victims of the main group with deep burns, the cytological method of studying wound prints was used, the comparison group consisted of 32 patients with burns of the same depth and area in which indications for autodermoplasty were determined based on visual criteria.&#x0D; The results of the study and their discussion. The goal of local preoperative treatment was to achieve an inflammatory-regenerative type of cytograms with a significant decrease in leukocytes, degenerative-destructive forms of neutrophils and the number of bacterial cells. At the same time, the number of polyblasts, macrophages and fibroblasts increased significantly, and there was also a tendency to increase the percentage of lymphocytes. In the main group, autodermoplasty operations were performed only when the indicated type of cytograms was achieved, which allowed to improve the percentage of engraftment of skin flaps, reduce the number of surgical interventions and the treatment time.&#x0D; Conclusion. For the prognostic assessment of the readiness of deep burns for skin grafting, the cytological method of wound prints was applied. Determination of regenerative types of wound prints gives rise to autodermoplasty.

Ecological Analysis of Pacific White Shrimp (Litopenaeus Vannamei) Cultivation: Rokan Hilir and Dumai Context

The research was aimed to analyzed ecologically feasibility and prospective of Pacific white shrimp (Litopenaeus vannamei) cultivation in Rokan Hilir Regency and City of Dumai. The sudy was conducted from January 2017 to April 2018 in 5 sub-districts; Sungai Sembilan (City of Dumai), Sinaboi, Rimba Melintang, Bangko and Batu Hampar (Rokan Hilir District), Riau Province, Indonesia. Water samples were collected at the Senepis River, Nyamuk River, Sinaboi River, Teluk Dalam River, RKT plot and Camp Pemda in the Diamond Raya Timber concession area. It was noted; pH (5.22-7.0), salinity (5.0 to 22.5), phosphate (0.4-1.263 mg/L), ammonia (0.03-0.352 mg/L), nitrate (0.346-0.379 mg/L), CO2 (15.980-123.685 mg/L) DO (2.7-5.7 mg/L) COD (70.4-114.4 mg/L), BOD (4.85-6.4 mg/L) and number of Coliform bacterial cells (7.0-233.05 cfu/100 ml). The dominant species of fish caught in river waters are common species, as in zooplankton, phytoplankton, benthos, and manngrove community. Based on species data, abundancy index, diversity index, homogenity index and dominance index shows that the waters are still in normal condition. The study conclude the area is still in normal condition and suitable for Pacific white shrimp cultivation.

Online characterization of bacterial processes in drinking water systems

The use of traditional drinking water microbial quality monitoring methods, including heterotrophic plate counts (HPCs) and total coliform counts, are not only laborious and time-consuming but also do not readily allow identification of risk areas in the network. Furthermore, if areas of concern are identified, and mitigation measures are taken, it takes days before the effectiveness of these measures is known. This study identified flow cytometry (FCM) as an online sensor technology for bacterial water quality monitoring in the distribution network. We monitored the total bacterial cell numbers and biodiversity in a drinking water distribution system (DWDS) using an online FCM. Two parallel online FCM monitoring systems were installed on two different locations at a drinking water treatment plant (DWTP; Saudi Arabia) supplying chlorinated water to the distribution and in the network 3.6 km away from the DWTP. The FCMs were operated at the same time in parallel to assess the biological stability in DWDSs. The flow cytometric data was compared with the conventional water quality detection methods (HPC and total coliforms). HPC and total coliforms were constantly below the detection limits, while the FCM provided detectable total cell count data and enabled the quantification of changes in the drinking water both with time and during distribution. Results demonstrate the value of FCM as a tool for compliance monitoring and risk assessment of DWDSs.

Antibacterial and Antioxidant Activity of Extracts from Rose Fruits (Rosa rugosa).

The aim of the present study was to determine the antioxidant and antimicrobial properties in freeze-dried extracts of rose fruits (Rosa rugosa) obtained using various extraction techniques and to determine the effect of a selected extract on bacterial survival in model fluids imitating protein food. Ethanolic extracts from rose fruits showed higher antioxidant activity compared to other tested extracts. The rose fruits aqueous extract showed the highest inhibitory activity against most of the 10 bacterial strains tested. From the group of Gram-positive bacteria, the Bacillus cereus strain proved to be the most sensitive to the action of the rose extract. From the Gram-negative bacteria: Escherichia coli and Klebsiella pneumoniae were the most sensitive. The reduction in the number of bacterial cells in matrices imitating protein food depended on the concentration of the aqueous extract used. However, at none of the concentrations used was a complete inhibition of bacterial growth observed. We have confirmed that the traditional extraction and freeze-drying of rose fruits is still suitable for the food industry due to obtaining extracts with good antibacterial and antioxidant properties and the use of bio-solvents, such as water or ethanol, which are easily available in high purity and completely biodegradable.

Antibacterial efficacy of chitosan- and poly(hexamethylene biguanide)-immobilized nanofiber membrane

In this study, polyacrylonitrile (PAN) nanofiber membrane was prepared by an electrospinning technique. After alkaline hydrolysis, the ion-exchange nanofiber membrane (P-COOH) was grafted with chitosan molecules to form a chitosan-modified nanofiber membrane (P-COOH-CS). Poly(hexamethylene biguanide) (PHMB) was then covalently immobilized on P-COOH and P-COOH-CS to form P-COOH-PHMB and P-COOH-CS-PHMB, respectively. The nanofiber membranes were subjected to various surface analyses as well as to the evaluations of antibacterial activity against Escherichia coli. The optimal modification conditions for P-COOH-CS-PHMB were attained by water-soluble chitosan at 50 kDa of molecular weight, coupling pH at 7, and 0.05% (w/w) of PHMB. Within 10 min of treatment, the antibacterial rate was close to 100%. Under the similar conditions of antibacterial treatment, the P-COOH-CS-PHMB exhibited a better antibacterial efficacy than the P-COOH-PHMB. When the number of bacterial cells was increased by 2000 folds, both types of nanofiber membranes still maintained the antibacterial rate close to 100%. After five cycles of repeated antibacterial treatment, the antibacterial efficacy of P-COOH-PHMB was 96%, which was higher than that of P-COOH-CS-PHMB (83%). The experimental results revealed that the PHMB-modified nanofiber membranes can be suitably applied in water treatment such as water disinfection and biofouling control.

Direct culture-free electrochemical detection of Salmonella cells in milk based on quantum dots-modified nanostructured dendrons

With regard to global food safety and preventing the spread of diseases caused by foodborne pathogens or their toxins, there is an increasing need for simple and rapid methods for the screening of such pathogens. We aimed to develop a fast and efficient biosensor for the screening of milk samples contaminated by Salmonella spp. and provide a quick and cost-effective method as an alternative to the time-consuming conventional cultivation- or PCR-based approaches. We exploited a simple but highly specific technique whereby bacterial cells were separated immunomagnetically, with subsequent reaction with conjugate; i.e. specific IgG molecule labelled with an electrochemically potent indicator. The unique structure of this indicator exploits the benefits of hyperbranched dendron molecules and heavy metal–derived quantum dots (QDs). Square-wave anodic stripping voltammetry (SWASV) using of screen-printed carbon electrodes with in situ formed Bi(III) film (BiSPCE) was used for the detection and quantification of metal ions released from the QDs (CdTe) after their acidic dissolution. The metal ion signals proportionally correlate with the amount of captured bacteria cells. By this method, the presence of Salmonella spp. was proven in 2.5 h even in minimal number of bacterial cells (4 CFU) in 1 mL of the sample.

Antibacterial effectiveness of calcium hydroxide alone or in combination with Ibuprofen and Ciprofloxacin in teeth with asymptomatic apical periodontitis: a randomized controlled clinical study.

To evaluate the antimicrobial effectiveness of Ca(OH)2 paste combined with Ibuprofen or Ciprofloxacin in infected root canals of teeth with asymptomatic apical periodontitis. Forty-five patients were randomly divided into three groups using a web programme according to the medication selected: Ca(OH)2 : 1g Ca(OH)2 powder with 1mL propylene glycol, Ca(OH)2 +Ibuprofen: 50mg of Ibuprofen was added into 950mg Ca(OH)2 powder and mixed with 1mL propylene glycol, Ca(OH)2 +Ciprofloxacin: 50mg of Ciprofloxacin was added into 950mg Ca(OH)2 powder and mixed with 1mL propylene glycol. Root canal bacteriological samples were collected before root canal treatment (S1) and after chemo-mechanical procedures (S2). After root canal preparation, the intracanal medicaments were placed into the root canals to a level approximately 1mm short of the working length using K-files and access cavities were filled temporarily. The participants were scheduled for a second visit 7days later when the medication was removed mechanically, and after irrigation of the root canals, the final samples (S3) were collected. Samples were subjected to quantitative real-time polymerase chain reaction to evaluate the numbers of total bacteria, Enterococcus faecalis and Streptococcus species. For intragroup analysis, a Friedman test was used to compare reduction of counts of total bacteria, Streptococci and E.faecalis amongst the three samples (S1, S2 and S3). The chi-square test was used to compare the number of root canals positive for bacteria in S1, S2 and S3 amongst the groups. Intragroup analysis revealed a significant reduction in the number of intracanal bacterial cells from S1 to S2 and from S2 to S3 in all medication groups (P<0.01). Although there was no significant difference amongst the groups when comparing quantitative S1 or S2 data, there were significantly lower bacterial counts in the Ca(OH)2 +Ciprofloxacin group (0.49×102 ) than the pure Ca(OH)2 (1.25×102 ) and Ca(OH)2 +Ibuprofen groups (0.76×102 ) at S3. The percentage reduction from S1 to S3 and from S2 to S3 was significantly greater in the Ca(OH)2+Ciprofloxacin than the pure Ca(OH)2 and Ca(OH)2+Ibuprofen groups (P<0.05). In the Ca(OH)2 +Ciprofloxacin group, there were significantly fewer positive cases (8/15) than the pure Ca(OH)2 (13/15) and Ca(OH)2 +Ibuprofen (13/15) groups (P<0.05). The addition of Ciprofloxacin to Ca(OH)2 provided further antibacterial effectiveness when used as an intracanal medicament in vivo during root canal treatment.

Counting of Bacterial Colonies of the Low Quality Image Using Perona-Malik Diffusion Filters and Image Morphology Operators

Microbiology has an important role in solving human problems that are complex in many fields, such as environment, medical, and biotechnology. One of the important researches in microbiology fields is the counting of the number of bacterial colonies. This research is very important to estimate the number of bacterial cells in each millilitre or gram sample. However, the manual counting of bacterial colonies is a time-consuming task and is also very tedious. To help microbiologists, an automatic counting method of bacterial colonies based on bacterial colonies images is needed to be developed. However, the bacterial colonies images taking by the phones camera has low-quality. They are noise presence and lack of contrast, so the pre-processing method is necessary to be developed. This paper proposes the pre-processing method by using modified Perona-Malik Diffusion (PMD) and Contrast Limited Adaptive Histogram Equalization (CLAHE). The modified PMD filter is used to reduce noise, while the CLAHE method is used to enhance the contrast. Moreover, the morphology operators are used for the petri dish extraction and bacterial colonies counting process. The experimental results show that the proposed method has better performance than the original PMD based on the average values of precision, recall, and F-measure.

Comparison of planktonic and reed biofilm bacteria in different riverine water bodies of river Danube

AbstractAs the submerged shoot parts of common reed (Phragmites australis) can provide large surfaces for biofilm‐forming bacteria, extensive reed stands can effectively contribute to the self‐purification in the littoral zones of freshwaters. However, bacterial biofilm developed on reed surfaces have been studied only in still waters. In the present study, comparative examinations were performed on the planktonic and reed biofilm bacterial communities from two different riverine water bodies. Water and reed biofilm samples were taken at the beginning and end of the vegetation period from (a) a regulated side arm and (b) a separated oxbow of River Danube. Besides measuring physical and chemical environmental variables, planktonic bacterial cell numbers were detected by 4′,6‐diamidino‐2‐phenylindole staining method, and the bacterial communities were compared by denaturing gradient gel electrophoresis. Our results demonstrated that the structure and composition of bacterial communities correlated with different environmental variables and were different regarding both the habitats (planktonic vs. reed biofilm) and the types of riverine water bodies. The seasonal differences in the bacterial community structures were smaller in the river side arm than in the separated oxbow. In the water column, representatives of widespread and typical freshwater planktonic bacteria (“Candidatus Planktophila,” Limnohabitans, and Polynucleobacter), whereas, in the reed biofilm samples, phototrophic and plant associated bacteria were identified.

Evaluation of the specific uptake of radiolabeled Staphylococcus aureus aptamers in the infectious foci

The specific uptake of 99mTc radiolabeled Staphylococcus aureus aptamers in the infectious foci was evaluated by scintigraphic imaging of infection-bearing mice. The radiotracer uptake was inhibited by non-radiolabeled aptamers in a competition assay. In addition, when a different number of bacterial cells was used to infect mice an increase in the target/non-target ratios of images correlated with the increase of CFU per gram of tissue was verified. These results confirmed that 99mTc-aptamers were specific to bacterial focus and the level of uptake was dependent on the number of bacterial cells.

Antimicrobial Effects of Zataria multiflora Extract Mouthrinse on Orthodontic Elastomeric Ligatures- an In Vitro Study

Objectives: The aim of this study was to evaluate and compare antibacterial and antifungal effects of different concentrations of Zataria multiflora extract mouthrinse. Methods: In this lab trial study, 128 elastomeric ligatures were divided into 2 groups of 64. Before disinfection eight ligatures of each group were randomly selected to evaluate the microbial load. The remaining ligatures in each group (n = 58) were divided into 7 subgroups of 8. All samples in group 1 (G1) contaminated with Streptococcus mutans (S. mutans) and in group 2 (G2) contaminated with Candida albicans (C. albicans). Then, Zataria multiflora extract in 1%, 0.1%, 0.01%, 0.001%, 0.0001% concentrations as decontamination agent were used in 5 subgroups of each group. Positive control consisted of penicillin in G1 and nystatin in G2. For the negative control in both groups phosphate buffered saline was used. The average number of adhered viable bacterial cell after performing the disinfection protocols were calculated and compared. The collected data was statistically analyzed by Kruskal-wallis, Wilcoxon and Mann-Whitney test using SPSS software version 18 at a significant level of 0.05. Results: Results showed that penicillin, nystatin, Zataria multiflora extract in 1% and 0.1% concentrations completely eliminated C. albicans and S. mutans on elastomeric ligatures. Statistically significant differences were found between the number of adhered S. mutans and C. albicans before and after performing the all five concentrations of disinfection solutions (P = 0.01). Also higher concentrations of Zataria multiflora showed more antibacterial effectse in both groups. Conclusions: Zataria multiflora extract mouthrinse showed antibacterial and antifungal characteristics and could be useful for patients under orthodontic treatment.

Characterizing Quorum Sensing-Induced Bioluminescence in Variable Volumes With Vibrio fischeri Using Computer Processing Methods

Bacteria use the mechanism of quorum sensing to gather information about the density of other cells in their surroundings. Quorum sensing, in which bacteria sense chemical signals that increase in concentration as a function of surrounding cell density, leads to downstream changes in bacterial gene expression. These changes may include the activation of virulence or bioluminescence. In this study, we used Vibrio fischeri as a model to study the activation of bioluminescence by quorum sensing. We inoculated the same number of bacterial cells in 3 different culture volumes (1mL or small volume, 3mL or medium volume, and 5mL or large volume) and measured luminescence of the cultures over time. Using digital image processing to determine changes in luminescence over time, we found that cultures in smaller volumes reached peak illumination densities in less time than those in larger volumes. These results suggest that V. fischeri luminesce in response to cell density information in the environment and that we can use computer processing methods to study quorum sensing-induced bioluminescence. Studying the mechanisms by which bacteria use quorum sensing to activate gene expression may facilitate the development of therapies to inhibit bacterial virulence in the context of infectious disease.