Comparison of electrochemical dissolution of chalcopyrite and bornite in acid culture medium

The electrochemical dissolution process of chalcopyrite and bornite in acid bacteria culture medium was investigated by electrochemical measurements and X-ray photoelectron spectroscopy（XPS） analysis. Bornite was much easier to be oxidized rather than to be reduced, and chalcopyrite was difficult to be both oxidized and reduced. The relatively higher copper extraction of bornite dissolution can be attributed to its higher oxidation rate. Covellite（CuS） was detected as the intermediate species during the dissolution processes of both bornite and chalcopyrite. Bornite dissolution was preferred to be a direct oxidation pathway, in which bornite was directly oxidized to covellite（CuS） and cupric ions, and the formed covellite（CuS） may inhibit the further dissolution. Chalcopyrite dissolution was preferred to be a continuous reduction-oxidation pathway, in which chalcopyrite was initially reduced to bornite, then oxidized to covellite（CuS）, and the initial reduction reaction was the rate-limiting step.

Different Explants of Lilium lancifolium Have Different Potential to Differentiate and Regenerate in Tissue Culture

[Objective] The aim was to investigate differences in differentiation and regeneration of the explants from different parts of Lilium lancifolium（Yixing Lily） in tissue culture.[Method] The different parts of scale,leaf and root of Yixing Lily were cultured as explants on MS basic medium supplemented with different concentrations of plant growth regulators,so as to compare their capacity to differentiate and regenerate.[Result] The explants had different potential to differentiate（scale root leaf）.The capacity of different scale parts to differentiate was the lower part middle partupper part;the capacity of different leaf parts to differentiate was the leaf base middle part leaf tip;the capacity of different root parts to differentiate was the root base root tip middle part.[Conclusion] Tissue culture could be well applied in propagation of Yixing Lily.

Differentiation potential of human adipose tissue derived stem cells into photoreceptors through explants culture and enzyme methods

AIM： To investigate the retinal photoreceptor differentiation potential of human orbital adipose tissue-derived stem cells （ADSCs） generated by enzyme （EN） and explant （EX） culture methods.METHODS： We investigated potentials of human orbital ADSCs to differentiate into photoreceptors through EN and EX culture methods. EN and EX orbital ADSCs were obtained from the same donor during rehabilitative orbital decompression, and then were subject to a 3-step induction using Noggin, DKK-1, IGF-1 and b-FGF at different time points for 38d. Stem cell, eye-field and photoreceptor-related gene and protein markers were measured by reverse transcription-polymerase chain reaction （RT-PCR） and immunofluorescent （IMF） staining.RESULTS： Both EX and EN orbital ADSCs expressed CD133, a marker of cell differentiation. Moreover, PAX6 and rhodopsin, markers of the retinal progenitor cells, were detected from EX and EN orbital ADSCs. In EX orbital ADSCs, PAX6 mRNA was detected on the 17th day and then the rhodopsin mRNA was detected on the 24th day. In contrast, the EN orbital ADSCs expressed PAX6 and rhodopsin mRNA on the 31st day. EX orbital ADSCs expressed rhodopsin protein on the 24th day, while EN orbital ADSCs expressed rhodopsin protein on the 31st day. CONCLUSION： Orbital ADSCs isolated by direct explants culture show earlier and stronger expressions of markers towards eye field and retinal photoreceptor differentiation than those generated by conventional EN method.

Screening and Characterization of Nitrite-Degrading Bacterial Isolates Using a Novel Culture Medium

In this study,a novel culture medium that simulates shrimp pond conditions was established to screen nitrite-degrading isolates.The medium was supplemented with nitrite as a nitrogen source and shrimp feed as the major carbon source,to achieve the high nitrogen and low carbon nutritional status found in shrimp farming ponds.Screening using this medium identified potent denitrifying Bacillus isolates,among which Bacillus subtilis M7-1 was considered best.M7-1 was able to completely degrade nitrite-N in 24 h without much consumption of dissolved oxygen.Efficient denitrification activity took place in liquid cultures within a set of non-stringent ranges of pH(5.0–9.0),salinity(0–30)and temperature(25–35℃).The denitrifying enzyme gene was amplified,sequenced and further identified as nirS type.In biosecurity assessments,M7-1 had no negative effects on shrimps at a dose of 106 cfu mL−1.M7-1 could therefore be used in aquaculture to reduce and control the nitrogen concentration,and to promote the development of sustainable and healthy culture systems.

Study on Microwave Sterilization of Solid Culture Medium

In this paper,microwave sterilization craft of solid culture medium in fungus growth is studied.The results show that microwave not only can be used to sterilize the micro-organisms which is useless for fungus growth in the solid culture medium,but also has positive effect on fungus growth;and the sterilization process is featured with shorter time and higher efficiency compared with the traditional method.

Effect of peripheral nerve on the neurite growth from retinal explants in culture

The effect of peripheral nerve (PN) on neurite outgrowth from retinal explants of adult hamsters was examined. Cultures of retinal explants, and co-cultures of retinal explants and PN were performed using chick retinal basement membrane (BM) as substrate. The presence of PN increases the number and length of neurite outgrowth. In addition, a high proportion of neurites situated close to PN tend to grow towards it. Since there was no contact between retinal ex-plants and PN, we suggest that PN might secrete diffusible substances to attract the neurites to grow towards it.

Efficient Disinfection of Explants in the Tissue Culture of Chinese Orchids

Explants,namely the seeds (Cymbidium faberi) and buds (Cymbidium goeringii) of local Hunan orchids were disinfected with 75% ethanol, 0.1% mercuric chloride,and 10% sodium hypochlorite in six different disinfection treatments. Results showed that The treatment with 75% ethanol (contact time: 45 s) and 0.1% mercuric chloride (contact time: 8 min) proved to be the most effective one in disinfecting the explants of Cymbidium faberi seeds.The combination of 75% ethanol (contact time: 45 s) and 0.1% mercuric chloride (contact time: 5 min) provided the optimal disinfection effects when disinfecting Cymbidium goeringii buds.In general, the disinfection effect of mercuric chloride was found to be superior to that of sodium hypochlorite,but care should be taken with the disinfection time to avoid damage to the explants.

Improved elastase production by Bacillus sp. EL31410—further optimization and kinetics studies of culture medium for batch fermentation

An efficient culture medium producing a bacterial elastase with high yields was developed further following preliminary studies by means of response surface method. Central composite design (CCD) and response surface method-ology were applied to optimize the medium constituents. A central composite design was used to explain the combined effect of three medium constituents, viz, glucose, K2HPO4, MgSO47H2O. The strain produced more elastase in the completely optimized medium, as compared with the partially optimized medium. The fitted model of the second model, as per RSM, showed that glucose was 7.4 g/100 ml, casein 1.13 g/100 ml, corn steep flour 0.616 g/100 ml, K2HPO4 0.206 g/100 ml and MgSO47H2O 0.034 g/100 ml. The fermentation kinetics of these two culture media in the flask experiments were analyzed. It was found that the highest elastase productivity occurred at 54 hours. Higher glucose concentration had inhibitory effect on elastase production. At the same time, we observed that the glucose consumption rate was slow in the completely optimized medium, which can explain the lag period of the highest elastase production. Some metal ions and surfactant additives also affected elastase production and cell growth.

Evaluation of Endotoxin in Culture Medium for Human in vitro Fertilization

To determine whether the presence of bacterial endotoxin in the commercial culture media utilized for human in vitro fertilization （IVF）, and evaluate the difference in detecting endotoxin in culture medium between the human sperm motility assay and the 2-cell mouse embryo assay. Methods Thirty-six batches of culture media commonly used in IVF laboratories from 3 manufacturers were determined for thepresence ofendotoxin before using the medium for the assisted reproductive programs （group A）. After being used, 25 specimens among above media were also tested （group B）. The chromogenic limulus amoebocyte lysate （LAL） test was used for quantification the content of endotoxin. In addition, the human sperm motility assay was compared with the 2-cell mouse embryo assay to evaluate the difference in detecting endotoxin in culture medium. Results Endotoxin was not detected in group A. However, 2 samples were positive in group B, Sperm did not show significant change in motility in group A during 24 h of incubation when compared with the control （P〉0. 05）. However, in group A the 2-cell embryo development to blastocyst was suppressed in 3 batches of media. Conclusions Regular screening of each batch of culture medium should be performed if possible although there was no evidence of endotoxin contamination in commercially prepared pre-tested media. Culture environment should be stringently controlled in case the medium is polluted. The sensitivity of the sperm motility assay was lower than that of the mouse embryo assay for detecting low levels of endotoxin or toxic compounds in the medium.

Response of Two Sweet Potato （Ipomoea batatas L. Lam） Varieties Regenerated on Low Cost Tissue Culture Medium

Plant tissue culture continues to be of great interest within the realms of molecular biology, plant breeding and plant health However, different plant cultivars have different culture efficiencies to tissue culture. In this research, the response of two Kenyan sweet potato varieties, KEMB 36 and Tainurey, cultured on a low cost tissue culture medium was evaluated. The low cost medium contained plant nutrients that were obtained from locally available fertilizers. Each conventional Murashige and Skoog （MS） macronutrient was individually substituted with a locally available fertilizer. The conventional source of micronutrients was substituted with Stanes~ Iodized Microfood while sucrose was obtained from table sugar. Performance of the two cultivars was monitored over a period of six weeks. KEMB 36 had a better performance than Tainurey with an average of eight nodes, seven leaves, three roots and height of four centimeters per plantlet indicating genotype-dependent response.

Plantlet regeneration from mature zygotic embryos andembryonic explants of masson pine (Pinus massoniana Lamb.)

Excised zygotic embryos, cotyledons and hypocotyls of juvenile seedlings of masson pine were grown on DCR medium supplemented with several concentrations of various plant phytohormones. BA (1.0 mg/ L) in combination with NAA (0.05 mg/L)in DCR medium was found to increase the formation of adventitious buds from mature zygotic embryos, but most of them were formed at the tips of embryonic cotyledons. Adventitious buds were obtained from cotyledons and hypocotyls from juvenile seedlings when they were cultured on DCR medium containing BA 3-5 mg/L and NAA 0.1-0.2 mg/L. Elongation of buds were observed on hormone-free DCR medium with or without activated charcoal (0.5%). Root initiation was achieved with full or half strength DCR inedium supplemented with IBA 1.0 mg/L and NAA 0.25-0.5 mg/L. Approximately 11-20 axillary buds formed on each explant when juvenile seedling explants were treated (3-20h) with BA 50-100 mg/L, followed by transfer to hormone-free DCR medium. The maximum number of shoots obtained per explant within six months was 33.

In vitro clonal propagation of Achyranthes aspera L. and Achyranthes bidentata Blume using nodal explants

Objective:To develop the reproducible in vitro propagation protocols for the medicinally important plants viz.,Achyranthes aspera(A.aspera)L.and Achyranthes bidentata(A.bidentata)Blume using nodal segments as explants.Methods:Young shoots of A.aspera and A.bidentata were harvested and washed with running tap water and treated with 0.1%bavistin and rinsed twice with distilled water.Then the explants were surface sterilized with 0.1%(w/v)HgCl_2 solutions for I min.After rinsing with sterile distilled water for 3-4 times,nodal segments were cut into smaller segments(1 cm)and used as the explants.The explants were placed horizontally as well as vertically on solid basal Murashige and Skoog(MS)medium supplemented with 3%sucrose,0.6%(w/v)agar(HiMedia,Mumbai)and different concentration and combination of 6-benzyl amino purine(BAP),kinetin(Kin),naphthalene acetic acid(NAA)and indole acetic acid(IAA)for direct regeneration.Results:Adventitious proliferation was obtained from A.aspera and A.bidentata nodal segments inoculated on MS basal medium with 3%sucrose and augmented with BAP and Kin with varied frequency.MS medium augmented with 3.0 mg/L of BAP showed the highest percentage(93.60±0.71)of shootlets formation for A.aspera and(94.70±0.53)percentages for A.bidentata.Maximum number of shoots/explants(10.60±0.36)for A.aspera and(9.50±0.56)for A.bidentata was observed in MS medium fortified with 5.0 mg/L of BAP.For A.aspera,maximum mean length(5.50±0.34)of shootlets was obtained in MS medium augmented with 3.0 mg/L of Kin and for A.bidentata(5.40±0.61)was observed in the very same concentration.The highest percentage,maximum number of rootlets/shootlet and mean length of rootlets were observed in 1/2 MS medium supplemented with 1.0 mg/L of 1BA.Seventy percentages of plants were successfully established in polycups.Sixty eight percentages of plants were well established in the green house condition.Sixty five percentages of plants were established in the field.Conclusions:The results have shown that use of nodal buds is an alternative reproducible and dependable method for clonal propagation of A.aspera and A.bidentata.The high rate of direct shoot-root multiplication and their high rate of post-hardening survival indicate that this protocol can he easily adopted for commercial large scale cultivation.

Effects of Genotypes and Basic Medium on Culture of Maize Mature Embryos

[Objective]This study was to screen out suitable genotypes and basic medium for the culture of maize mature embryos.[Method]Using mature embryos of nine maize genotypes as explants,the effects of genotypes and basic medium on callus induction and subculture were investigated.[Result]The genotypes performed better in callus induction and subculture were found in turn 853-35,853-209,Dan 34 and 81162.MS medium is better than N6 medium in the callus induction from maize embryos,while N6 medium is more suitable for callus subculture.[Conclusion]Our study further improved the tissue culture system in maize with mature embryos as explants.

Propagation of Abies beshanzuensis by Water Cultured Medium

[Objective] The experiment aimed to explore the influences of phytohormones (ABT and IAA) and nutrient solution on rooting of Abies beshanzuensis M.H.Wu by water cultured medium. [Method] The Abies beshanzuensis M.H.Wu were treated by water (CK), 10 mg/L ABT+ water, 10 mg/L IAA+ water, 10 mg/L ABT+ hoagland solution, 10 mg/L IAA+ hoagland solution, then the rooting process was observed and the formation rate of callus, rooting rate, number of rooting, and root length were investigated and analyzed. [Result] ABT and IAA had obvious influences on callus induction, rooting rate and the number of root of Abies beshanzuensis M.H.Wu by water culture, so they were suitable to be used in water propagation of Abies beshanzuensis M.H.Wu. The treatments of phytohormones had no regular influences on the longest root length and average root length. The nutrient solutions would not generate obvious influence on propagation of Abies beshanzuensis M.H.Wu at firstly stage, but they generated influence on root growth after rooting. [Conclusion] The research provided new ideas for propagation of Abies beshanzuensis M.H.Wu, which could make it out of endangerment situation quickly.

Character of cell-free genomic DNA in embryo culture medium and the prospect of its clinical application in preimplantation genetic testing

There is increasing evidence that cell-free DNA (cfDNA) in spent culture media (SCM) can be amplified for genetic testing. Therefore, this paper reviews the characteristics of cfDNA, including its fragment size, amount, origin, as well as some factors affecting the success rate of its amplification, together to provide researchers with a more comprehensive perspective on embryonic cfDNA. The origin of cfDNA in SCM is complicated and poses challenges to the interpretation of genetic test results. Advanced molecular techniques should distinguish between embryonic and contaminated DNA to maximize the success rate of amplification and analysis. Recent data showed that the type of culture medium, assisted hatching or not, the type of amplification kit, and fresh or thawed embryos were not related to the success rate of amplification, but the length of culture time might affect the success rate. The longer culture time, the more cfDNA is available in the SCM. Then we focused on the concordance between trophectoderm (TE), inner cell mass, whole embryo, and embryonic cfDNA. Despite successful amplification, the concordance between TE and embryonic cfDNA was low. In summary, non-invasive genetic testing using SCM could represent a major advance in future single embryo selection, however, contamination and timing for media collection are key factors affecting the results, and current non-invasive cfDNA testing should not be directly applied to clinical practice. Further research is needed to improve the methods used for testing techniques and genetic analysis to achieve greater accuracy and trace its origins before it can be used in the clinics.

Optimization of Culture Conditions and Medium Composition for the Marine Algicidal Bacterium Alteromonas sp. DH46 by Uniform Design

Harmful algal blooms(HABs) have led to extensive ecological and environmental issues and huge economic losses.Various HAB control techniques have been developed,and biological methods have been paid more attention.Algicidal bacteria is a general designation for bacteria which inhibit algal growth in a direct or indirect manner,and kill or damage the algal cells.A metabolite which is strongly toxic to the dinoflagellate Alexandrium tamarense was produced by strain DH46 of the alga-lysing bacterium Alteromonas sp.The culture conditions were optimized using a single-factor test method.Factors including carbon source,nitrogen source,temperature,initial pH value,rotational speed and salinity were studied.The results showed that the cultivation of the bacteria at 28℃ and 180 r min-1with initial pH 7 and 30 salt contcentration favored both the cell growth and the lysing effect of strain DH46.The optimal medium composition for strain DH46 was determined by means of uniform design experimentation,and the most important components influencing the cell density were tryptone,yeast extract,soluble starch,NaNO3 and MgSO4.When the following culture medium was used(tryptone 14.0g,yeast extract 1.63g,soluble starch 5.0 g,NaNO3 1.6 g,MgSO4 2.3 g in 1L),the largest bacterial dry weight(7.36 g L-1) was obtained,which was an enhancement of 107% compared to the initial medium;and the algal lysis rate was as high as 98.4% which increased nearly 10% after optimization.

Investigation of Oxidation-Reduction Properties of Growing Mediums for Cell Culture of Mammals under the Effect of Cosmo-Geophysical Factors

In model experiments were studied the effect of cosmo-geophysical factors of environment (hypomagnetic conditions during 2 days ≈ 1 mkT;electromagnetic irradiation (10 min - 2 MHz with amplitude 5 V/m and power 30 mkVt, background 2 - 4 mkVt), γ-quantum (10 min—from the source 137Cs) and its combined effect on the physic-chemical properties (ORP and pH) of growing medium for cell culture of mammals as nutrition medium 199 (PanEco, Russia). It was used a clear solution of medium (solution 1) and with the adding of 10% embryo bull serum—model of bio-medium (solution 2). Hypomagnetic conditions evoked the decreasing of ORP and pH value in both solutions, electromagnetic irradiation in the solution 1 which evoked the decreasing of ORP and the increasing of pH value, and in the solution 2, on the contrary, the increasing of ORP with the unchanging pH value. γ-radiation sharply decreased ORP value and didn’t change pH in solution 1, i.e. the reduction properties increased. There is insignificant increasing of ORP value and the decreasing of pH is noted in the solution 2, that it is characterized with the increasing of oxidative properties of solution. Under the combined effect of hypomagnetic conditions and electromagnetic irradiation, the values of investigating parameters in the solution 1 decreased and in the solution 2 increased. It was observed acute decreasing of ORP value in both solutions under the combined effect of hypomagnetic conditions and γ-radiation, i.e. the reductive properties of the solutions increased sharply. In this the concentration H+ significantly decreased, (p γ-radiation led to the decreasing of ORP and pH values in both solutions. Thus, the studying factors significantly change the oxidation-reduction properties of growing mediums. The investigation of the processes in biological mediums plays the important role in the assessment of environment effect during the flight in inter-planet space.

Statistical optimization of medium composition and culture condition for the production of recombinant anti-lipopolysaccharide factor of Eriocheir sinensis in Escherichia coli

Anti-lipopolysaccharide factors （ALFs） are important antimicrobial peptides that are isolated from some aquatic species. In a previous study, we isolated ALF genes from Chinese mitten crab, Eriocheir sinensis. In this study, we optimized the production of a recombinant ALF by expressing E. sinensis ALF genes in Eseherichia coli maintained in shake-flasks. In particular, we focused on optimization of both the medium composition and the culture condition. Various medium components were analyzed by the Plackett-Burman design, and two significant screened factors, （NH4）2SO4 and KH2PO4, were further optimized via the central composite design （CCD）. Based on the CCD analysis, we investigated the induction start-up time, the isopropylthio-D-galactoside （IPTG） concentration, the post-induction time, and the temperature by response surface methodology. We found that the highest level of ALF fusion protein was achieved in the medium containing 1.89 g/L （NH4）2SO4 and 3.18 g/L KH2PO4, with a cell optical density of 0.8 at 600 nm before induction, an IPTG concentration of 0.5 mmol/L, a post-induction temperature of 32.7~C, and a post-induction time of 4 h. Applying the whole optimization strategy using all optimal factors improved the target protein content from 6.1% （without optimization） to 13.2%. We further applied the optimized medium and conditions in high cell density cultivation, and determined that the soluble target protein constituted 105% of the total protein. Our identification of the economic medium composition, optimal culture conditions, and details of the fermentation process should facilitate the potential application of ALF for further research.

The Skin Whitening Effect of Co-Cultured Conditioned Medium: Involvement of Synergy between Stem Cells and Immune Cells

Many researchers have described that mesenchymal stem cells conditioned medium and immune cells conditioned medium have a clear whitening effect when they are used as cosmetic ingredients. In this study, we confirmed the whitening efficacy of various concentrations of immune cells and stem cell conditioned media. The author tried to study a conditioned medium that has a strong whitening effect even with a composition of less than 20% (the most used concentration in cosmetics). Because of the fact that the conditioned medium contains various cytokines and growth factors secreted by stem cells or immune cells, it is known to have effects such as wound healing, antioxidant, and whitening effect. Recently, stem cells have been used not only in the development of cosmetic raw materials but also in skincare procedures, and there are reports being released of cosmetics using immune cells conditioned medium. The concentration-dependent whitening effect equivalently increased as the concentration of the mono-cultured conditioned medium was obtained through the stem cells or immune cells culture. In the case of co-culture, whitening results are like the effect of positive control such as arbutin in the medium carrying only 10% of the co-cultured conditioned medium. It is possible that enhanced whitening efficiency in co-cultured conditioned medium leads to a major innovation in the global cosmetic market.

大球盖菇液体菌种繁育工艺研究

【目的】优化大球盖菇液体菌种培养基,探究液体培养过程中的生长规律,确立液体菌种繁育栽培种工艺参数。【方法】以大球盖菇8号为试验菌株,以菌丝体生物量为评价指标,采用单因素和正交试验L9(34)优化液体菌种培养基。测定液体菌种菌丝体生物量,还原糖和氨基氮含量,羧甲基纤维素酶、淀粉酶、酸性蛋白酶、漆酶胞外酶酶活生理生化指标,确立优化配方的液体菌种最优培养时间。以平均满袋时间为指标,确立液体菌种扩繁栽培种接种量、培养基配方颗粒度和碳氮比。【结果】优化得到大球盖菇液体菌种最优配方为葡萄糖20 g·L^(-1)、小麦粉30 g·L^(-1)、酵母粉0.75 g·L^(-1)、磷酸二氢钾1.00 g·L^(-1)、硫酸镁0.50 g·L^(-1)、起始p H 5。培养第8天时,大球盖菇菌丝体生物量最大,为1.66 g·hm L^(-1);液体培养过程中还原糖含量由12.23 mg·m L^(-1)降至1.38 mg·m L^(-1),氨基氮含量由0.09mg·m L^(-1)降至0.06 mg·m L^(-1);羧甲基纤维素酶和淀粉酶酶活在第4天最高,酶活分别为6.49、5.16 U,酸性蛋白酶酶活在第2天最高,酶活为1.80 U,漆酶酶活在第6天最大,酶活为1.63 U。液体菌种扩繁栽培种生产工艺参数:接种量为15 m L,菌包培养基配方颗粒度的粗细木屑比为7∶3,碳氮比为50∶1。【结论】大球盖菇液体菌种活性与上述指标具有一定的相关性,结合发酵液生理生化指标,判定第7天的液体菌种活力最高。利用大球盖菇液体菌种扩繁栽培种,平均满袋时间为23.7 d,缩短生长周期2.7 d。本研究建立配套的制种工艺,为大球盖菇栽培种工厂化生产技术奠定基础。