scholarly journals Biomineralization Performance of Bacillus sphaericus under the Action of Bacillus mucilaginosus

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Yingying Hu ◽  
Weitao Liu ◽  
Wenjing Wang ◽  
Xinlei Jia ◽  
Lanjuan Xu ◽  
...  

Microbial Induced Calcite Precipitation (MICP) is a biochemical process widely found in nature, also known as microbial mineralization. This paper investigates whether this process can help promote the intelligent reinforcement and repair of underground projects such as mines and tunnels. We selected Bacillus sphaericus and Bacillus mucilaginosus as the research objects. The former has an outstanding urease production ability, and the latter can secrete carbonic anhydrase in vitro. Bacillus mucilaginosus was introduced into the culture solution of Bacillus sphaericus in the most suitable culture environment, and the changes of mineralization rate and mineralization yield of Bacillus sphaericus were observed and analyzed. The results revealed that, to maintain the highest growth rate of Bacillus sphaericus, the optimal pH value was between 7 and 8, the optimal urea concentration was 0.5 mol/L, the optimal Ca2+ concentration was 0.6 mol/L, and the optimal Luria-Bertani (LB) culture concentration was 20 g/L. The amount of biomineralized calcium carbonate precipitated in the double bacteria solution can reach 1.89 times the amount of the precipitation in the Bacillus sphaericus solution under the same conditions. It concludes that the introduction of Bacillus mucilaginosus can effectively increase the mineralization yield of Bacillus sphaericus without affecting the mineralized products.

1997 ◽  
Vol 36 (02) ◽  
pp. 71-75 ◽  
Author(s):  
S. Glatz ◽  
S. N. Reske ◽  
K. G. Grillenberger

Summary Aim: One therapeutic approach to rheumatoid arthritis and other inflammatory arthropathies besides surgical removal of inflamed synovium is radiation synovectomy using beta-emitting radionuclides to destroy the affected synovial tissue. Up to now the major problem associated with the use of labeled particles or colloids has been considerable leakage of radionuclides from the injected joint coupled with high radiation doses to liver and other non target organs. In this study we compared 188Re labeled hydroxyapatite particles and 188Re rhenium sulfur colloid for their potential use in radiation synovectomy. Methods: To this end we varied the labeling conditions (concentrations, pH-value, heating procedure) and analyzed the labeling yield, radiochemical purity, and in vitro stability of the resulting radiopharmaceutical. Results: After optimizing labeling conditions we achieved a labeling yield of more than 80% for 188Re hydroxyapatite and more than 90% for the rhenium sulfur colloid. Both of the radiopharmaceuticals can be prepared under aseptic conditions using an autoclav for heating without loss of activity. In vitro stability studies using various challenge solutions (water, normal saline, diluted synovial fluid) showed that 188Re labeled hydroxyapatite particles lost about 80% of their activity within 5 d in synovial fluid. Rhenium sulfur colloid on the other hand proved to be very stable with a remaining activity of more than 93% after 5 d in diluted synovial fluid. Conclusion: These in vitro results suggest that 188Re labeled rhenium sulfur colloid expects to be more suitable for therapeutic use in radiation synovectomy than the labeled hydroxyapatite particles.


2019 ◽  
Vol 16 (8) ◽  
pp. 688-697
Author(s):  
Ravinder Verma ◽  
Deepak Kaushik

: In vitro lipolysis has emerged as a powerful tool in the development of in vitro in vivo correlation for Lipid-based Drug Delivery System (LbDDS). In vitro lipolysis possesses the ability to mimic the assimilation of LbDDS in the human biological system. The digestion medium for in vitro lipolysis commonly contains an aqueous buffer media, bile salts, phospholipids and sodium chloride. The concentrations of these compounds are defined by the physiological conditions prevailing in the fasted or fed state. The pH of the medium is monitored by a pH-sensitive electrode connected to a computercontrolled pH-stat device capable of maintaining a predefined pH value via titration with sodium hydroxide. Copenhagen, Monash and Jerusalem are used as different models for in vitro lipolysis studies. The most common approach used in evaluating the kinetics of lipolysis of emulsion-based encapsulation systems is the pH-stat titration technique. This is widely used in both the nutritional and the pharmacological research fields as a rapid screening tool. Analytical tools for the assessment of in vitro lipolysis include HPLC, GC, HPTLC, SEM, Cryo TEM, Electron paramagnetic resonance spectroscopy, Raman spectroscopy and Nanoparticle Tracking Analysis (NTA) for the characterization of the lipids and colloidal phases after digestion of lipids. Various researches have been carried out for the establishment of IVIVC by using in vitro lipolysis models. The current publication also presents an updated review of various researches in the field of in vitro lipolysis.


2019 ◽  
Vol 16 (10) ◽  
pp. 940-950 ◽  
Author(s):  
Jiandong Yu ◽  
Zhi Chen ◽  
Yan-zhi Yin ◽  
Chaoyuan Tang ◽  
Enying Hu ◽  
...  

Background: In this study, a liposomal gel based on a pH-gradient method was used to increase the skin-layer retention of monocrotaline (MCT) for topical administration. Methods: Using the Box-Behnken design, different formulations were designed to form liposome suspensions with optimal encapsulation efficiency (EE%) and stability factor (KE). In order to keep MCT in liposomes and accumulate in skin slowly and selectively, MCT liposome suspensions were engineered into gels. Results: A pH-gradient method was used to prepare liposome suspensions. The optimal formulation of liposome suspensions (encapsulation efficiency: 83.10 ± 0.21%) was as follows: MCT 12 mg, soybean phosphatidyl choline (sbPC) 200 mg, cholesterol (CH) 41 mg, vitamin E (VE) 5 mg, and citric acid buffer solution (CBS) 4.0 10 mL (pH 7.0). The final formulation of liposomal gels consisted of 32 mL liposome suspensions, 4.76 mL deionized water, 0.40 g Carbopol-940, 1.6 g glycerol, 0.04 g methylparaben, and a suitable amount of triethanolamine for pH value adjustment. The results of in vitro drug release showed that MCT in liposomal gels could be released in 12 h constantly in physiological saline as a Ritger-Peppas model. Compared with plain MCT in gel form, liposomal MCT in gel had higher skin retention in vitro. Conclusion: In this study, liposomal gels were formed for greater skin retention of MCT. It is potentially beneficial for reducing toxicities of MCT by topical administration with liposomal gel.


Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2302
Author(s):  
Qingwen Yu ◽  
Zhiyuan Meng ◽  
Yichao Liu ◽  
Zehao Li ◽  
Xing Sun ◽  
...  

After an osteosarcoma excision, recurrence and bone defects are significant challenges for clinicians. In this study, the curcumin (Cur) loaded chitosan (CS) nanoparticles (CCNP) encapsulated silk fibroin (SF)/hyaluronic acid esterified by methacrylate (HAMA) (CCNPs-SF/HAMA) hydrogel for the osteosarcoma therapy and bone regeneration was developed by photocuring and ethanol treatment. The micro or nanofibers networks were observed in the CCNPs-SF/HAMA hydrogel. The FTIR results demonstrated that alcohol vapor treatment caused an increase in β-sheets of SF, resulting in the high compression stress and Young’s modulus of CCNPs-SF/HAMA hydrogel. According to the water uptake analysis, SF caused a slight decrease in water uptake of CCNPs-SF/HAMA hydrogel while CCNPs could enhance the water uptake of it. The swelling kinetic results showed that both the CCNPs and the SF increased the swelling ratio of CCNPs-SF/HAMA hydrogel. The accumulative release profile of CCNPs-SF/HAMA hydrogel showed that the release of Cur from CCNPs-SF/HAMA hydrogel was accelerated when pH value was decreased from 7.4 to 5.5. Besides, compared with CCNPs, the CCNPs-SF/HAMA hydrogel had a more sustainable drug release, which was beneficial for the long-term treatment of osteosarcoma. In vitro assay results indicated that CCNPs-SF/HAMA hydrogel with equivalent Cur concentration of 150 μg/mL possessed both the effect of anti-cancer and promoting the proliferation of osteoblasts. These results suggest that CCNPs-SF/HAMA hydrogel with superior physical properties and the bifunctional osteosarcoma therapy and bone repair may be an excellent candidate for local cancer therapy and bone regeneration.


Marine Drugs ◽  
2020 ◽  
Vol 18 (2) ◽  
pp. 82 ◽  
Author(s):  
Li Zhou ◽  
Fu Yang ◽  
Minghao Zhang ◽  
Jikai Liu

Krill oil enriched with polyunsaturated fatty acids is in the form of phospholipid. However, its application as a dietary supplement is limited, because of its rapid deterioration. Thus, this study aims to investigate the oxidative stability of krill oil extracted from Euphausia superba. Under optimal conditions (enzyme concentration 0.16%, enzymolysis time 2.9 h, and enzymolysis temperature of 45 °C) designed by response surface methodology, the extraction yield of krill oil is 86.02%. Five assays, including peroxide value (POV), thiobarbituric acid-reactive substances (TBARS), pH value, and turbidity were used to determine the oxidative stability of krill oil nanoliposomes during storage. Carboxymethyl chitosan (CMCS) nanoliposomes showed a significant reduction in POV and TBARS values, a prevention of pH value decrease and turbidity increase. This study indicated that CMCS nanoliposome can effectively improve the oxidative stability of krill oil during storage. Furthermore, the release profile in vitro illustrated that the controlled release of krill oil carried out by CMCS nanoliposomes is feasible.


2016 ◽  
pp. 39-44
Author(s):  
Ifra Tun Nur ◽  
Jannatun Tahera ◽  
Md Sakil Munna ◽  
M Majibur Rahman ◽  
Rashed Noor

With a previous observation of Escherichia coli growth cessation along with temperature variation within three different bacteriological culture media (nutrient agar, Luria-Bertani agar and minimal agar), current investigation further depicted on the possible growth dynamics of Escherichia coli (SUBE01) and Salmonella (SUBS01) growth and viability upon supplementation of different carbon sources (dextrose, sucrose, lactose, glycerol and tween 20) at 37°C under the aeration of 100 rpm. Viability of the tested bacterial species was assessed through the enumeration of the colony forming unit (cfu) appeared upon prescribed incubation for 12-24 hours on different agar plates consisting of the above mentioned carbon sources. Besides, to inspect the cellular phenotypic changes, morphological observations were conducted under the light microscope. Variations in bacterial growth (either growth acceleration or cessation) were further noticed through the spot tests on the agar plates. Considerable shortfalls in the culturable cells of E. coli and Salmonella spp. were noted in the minimal media separately consisting of sucrose, lactose, glycerol or tween 20 while an opposite impact of accelerated growth was noticed in the media supplied with dextrose. The data revealed a hierarchy of consequence of carbon sources as nutrient generators whereby the favourable bacterial growth and survival order of the carbon sources was estimated as dextrose > glycerol > lactose > tween 20 > sucrose.Bangladesh J Microbiol, Volume 32, Number 1-2,June-Dec 2015, pp 39-44


2019 ◽  
Author(s):  
Yuqing Chen ◽  
Wei Wu ◽  
Zeqiao Xu ◽  
Cheng Jiang ◽  
Shuang Han ◽  
...  

Abstract Background: Treatment of multidrug-resistant (MDR) bacterial infection is a great challenge in public health. Herein, we provide a solution to this problem with the use of graphene oxide-silver (GO-Ag) nanocomposites as anti-bacterial agent. Methods: Following established protocols, silver nanoparticles were grown on graphene oxide sheets. Then, a series of in-vitro studies were conducted to validate the antibacterial efficiency of the GO-Ag nanocomposites against clinical MDR Escherichia coli (E. coli) strains. Firstly, minimum inhibitory concentrations (MICs) of different antimicrobials were tested against MDR E. Coli strains. Then, bacteria viability assessments were conducted with different nanomaterials in Luria-Bertani (LB) broth. Afterwards, photothermal irradiation was conducted on MDR E. coli with lower GO-Ag concentration. At last, fluorescent imaging and morphology characterization using scanning electron microscope (SEM) were done to find the possible cause of antibacterial effect. Results: GO-Ag nanocomposites showed the highest antibacterial efficiency among tested antimicrobials. Synergetic antibacterial effect was observed in GO-Ag nanocomposites treated group. The remained bacteria viabilities were 4.4% and 4.1% respectively for different bacteria strains with GO-Ag concentration at 14.0 µg mL-1. In addition, GO-Ag nanocomposites have strong absorption in the near-infrared field and can convert the electromagnetic energy to heat. With the use of this photothermal effect, effective sterilization could be achieved using GO-Ag nanocomposites concentration as low as 7.0 µg mL-1. Fluorescent imaging and morphology characterization were used to analyze bacteria living status, which uncovered that bacteria integrity was disrupted after GO-Ag nanocomposites treatment. Conclusions: GO-Ag nanocomposites are proved to be efficient antibacterial agent against multi-drug resistant E. coli. Their strong antibacterial effect arises from inherent antibacterial property and photothermal effect that provides aid for bacteria killing.


2020 ◽  
Vol 23 (3) ◽  
pp. 82-84
Author(s):  
Lisa Kurniati ◽  
Andi Arjuna ◽  
Sukamto S Mamada

Nanopartikel ZnS merupakan material semi konduktor yang memiliki sifat unik dan manfaat yang besar dibidang kesehatan, terutama sebagai antibakteri dan biomarker kanker. Walaupun demikian, informasi mengenai toksisitas dari nanopartikel ZnS masih sangat terbatas. Oleh karena itu, pada penelitian ini telah dilakukan evaluasi hematotoksisitas secara in vitro nanopartikel ZnS hasil reduksi biomatriks Escherichia coli. Penyiapan nanopartikel ZnS diawali dengan pencampuran dispersi ZnSO4 konsentrasi 200 bpj ke dalam medium Luria Bertani Broth (LBB) yang ditumbuhi E.Coli  sebagai bioreduktor. Produk yang dihasilkan dikarakterisasi dengan uji photolimunisence (PL) dan spektrofotometri pada rentang panjang gelombang 250-700 nm. Hasilnya, nanopartikel ZnS berpendar biru dan diidentifikasi pada λmax 288 nm dengan absorbansi 0,905. Partikel yang dihasilkan kemudian didispersikan dengan variasi volume 30 µl, 40 µl, 50 µl pada larutan tyrod. Data persentase hemolisis secara berturut-turut adalah 32%, 39%, 22%, 0% (kontrol negatif) dan 100% (kontrol positif). Sehingga dapat disimpulkan bahwa nanopartikel ZnS hasil reduksi E.coli memberikan efek toksik terhadap sel darah merah


2015 ◽  
pp. 99-112
Author(s):  
Marija Markovic ◽  
Dragana Skocajic ◽  
Mihailo Grbic ◽  
Matilda Djukic ◽  
Dragica Obratov-Petkovic ◽  
...  

The aim of this study was to determine the possibility of micropropagation of the medicinal plant A. millefolium on half-strength MS medium and ex vitro rooting and acclimatization of the obtained microshoots in hydroculture in order to establish an efficient production method. Two explant types were used: basal and terminal cuttings, and better results were achieved when terminal cuttings were used. The development of shoots in the multiplication phase was successful with a regeneration percentage of 100%. Ex vitro rooting in a modified Hoagland nutrient solution was successful (83%), but the percentage of in vitro rooting on half-strength MS medium without hormones was higher (95%). However, bearing in mind that mass production of A. millefolium is more efficient when the phase of in vitro rooting is excluded, this method could be recommended for commercial propagation of this medicinal plant. It is necessary to conduct additional research in order to optimize the composition, EC and pH value of the hydroponic nutrient solution.


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