Cu(Nor)2·5H2O, a complex of Cu(II) with Norfloxacin: theoretic approach and biological studies. Cytotoxicity and genotoxicity in cell cultures

Norfloxacin is a fluoroquinolone antibiotic used in the treatment of bacterial infections. In this article, we studied the potential antitumoral action of a complex of Norfloxacin with Cu(II), Cu(Nor)₂·5H₂O on osteosarcoma cells (UMR106) and calvaria-derived cells (MC3T3-E1), evaluating its cytotoxicity and genitoxicity. We have also elucidated the more stable conformation of this complex under physiologic conditions by Molecular Dynamic simulations based on the model of the canonical ensemble and PM6 force field. When solvent effect was taken into account, the complex conformation with both carbonyl groups in opposite sides displayed lower energy. Cu(Nor)₂·5H₂O caused an inhibitory effect on the proliferation on both cell lines from 300 μM (P < 0.01). Nevertheless, the decline on cell proliferation of UMR106 cells was more pronounced (45 % vs basal) than in MC3T3-E1 cells (20 % vs basal) at 300 μM (P < 0.01). Cu(Nor)₂·5H₂O altered lysosomal metabolism (Neutral Red assay) in a dose-dependent manner from 300 μM (P < 0.001). Morphological studies showed important transformations that correlated with a decrease in the number of cells in a dose-dependent manner. Moreover, Cu(Nor)₂·5H₂O caused statistically significant genotoxic effects on both osteoblast cell lines in a lower range of concentrations (Micronucleus assay) (P < 0.05 at 10 μM, P < 0.001 from 25 to 50 μM). UMR106 cells displayed a dose-related genotoxic effect between 5 and 25 μM while the MC3T3-E1 cells showed a narrower concentration dependent range. Altogether, these results suggest that Cu(Nor)₂·5H₂O is a good candidate to be further evaluated for alternative therapeutics in cancer treatment.     

The Effect of Various Carbonate Sources on the Survival of Escherichia coli in Dairy Cattle Manure

Manure slurries (n = 3) prepared from the feces and urine of lactating dairy cattle (1 part urine, 2.2 parts feces, and 6.8 parts distilled water) had an initial pH of 8.6 ± 0.1; dissolved carbonate concentrations of 48 ± 4 mm, and Escherichia coli counts of 5.9 ± 0.7 logs per ml slurry. The pH of untreated slurries declined to pH 7.0 ± 0.1 by the 10th day of incubation, and the E. coli count increased approximately 10-fold (P < 0.05). When slurries were treated with Na₂CO₃, K₂CO₃, NaHCO₃ or Na₂CO₃·NaHCO₃ (0 to 16 g/kg slurry), the dissolved carbonates increased in a linear fashion, but only Na₂CO₃ and K₂CO₃ (8 g/kg or greater) or Na₂CO₃·NaHCO₃ (16 g/kg) ensured an alkaline pH. Even relatively low concentrations of Na₂CO₃ or K₂CO₃ (8 or 12 g/kg) caused a decrease in E. coli viability (P < 0.05), and E. coli could not be detected if 16 g/kg was added (day 5 or 10 of incubation). Na₂CO₃·NaHCO₃ also caused a decrease in E. coli viability, (P < 0.05), but some E. coli (approximately 10⁴ cells per g) were detected on day 10 even if the concentration was 16 g/kg. NaHCO₃ did not prevent the decrease in pH or cause a decrease in E. coli numbers (P > 0.05). Calculations based on the Henderson-Hasselbalch equation (pH and dissolved carbonates) indicated that little E. coli killing was noted until the dissolved carbonate anion concentrations (CO₃ ⁻²) were greater than 1 mm, but bicarbonate anion (HCO₃ ⁻) concentrations as high as 180 mm did not affect E. coli viability. These results are consistent with the idea that carbonate anion has antimicrobial properties and can kill E. coli in dairy cattle manure. Received: 20 December 2000 / Accepted: 7 February 2001     

In vitro and in vivo evaluation of xenogeneic bone putty with the carrier of hydrogel derived from demineralized bone matrix

The demineralized bone matrix (DBM) putty is a traditional bone graft utilized to facilitate the repair and reconstruction of bone. Recent studies indicated the DBM putties with the various carriers were different in bone repairing ability. In order to prepare a kind of DBM putty with a good biocompatibility and bioactivity, the DBM gel was processed from the DBM and the feasibility as a carrier for the DBM putty was evaluated. After the bovine DBM gel was prepared, the BMPs content as well as the ability to promote osteogenic differentiation of MC3T3-E1 cells in vitro were investigated. Then the DBM putty was prepared and filled into the rat calvarial defect model to evaluate the bone repairing ability by micro-CT and histology. The result showed there was 2.953?±?0.054 ng BMP contained in per gram of the DBM gel. And the ALP production of MC3T3-E1 cells in the DBM gels group increased with prolonged culturing, the mineralized nodules formed in MC3T3-E1 cells on 14th day after co-culture. The putty prepared by DBM gel was easy to handle without loss of DBM particles at room temperature. In the rat calvarial bone defect experiment, histological observation showed more mature bone formed in the DBM putty group than that in the type I collagen group at 12 weeks, which indicated the bone putty prepared by DBM gel exhibited a better bone repair capability.     

The influence of exogenous carbohydrate provision and pre-exercise alkalosis on the heat shock protein response to prolonged interval cycling

The aim of this study was to observe the intracellular heat shock protein 72 (HSP72) and heme oxygenase-1 (HSP32) response to prolonged interval cycling following the ingestion of carbohydrates (CHO) and sodium bicarbonate (NaHCO₃). Six recreationally active males (mean ± SD; age 23.2 ± 2.9 years, height 179.5 ± 5.5 cm, body mass 76.5 ± 6.8 kg, and peak power output 315 ± 36 W) volunteered to complete a 90 min interval cycling exercise on four occasions. The trials were completed in a random and blinded manner following ingestion of either: placebo and an artificial sweetener (P–P), NaHCO₃ and sweetener (B–P), placebo and CHO (P–CHO), and NaHCO₃ and CHO (B–CHO). Both HSP72 and HSP32 were significantly increased in monocytes and lymphocytes from 45 min post-exercise (p ≤ 0.039), with strong relationships between both cell types (HSP72, r = 0.83; HSP32, r = 0.89). Exogenous CHO had no influence on either HSP72 or HSP32, but the ingestion of NaHCO₃ significantly attenuated HSP32 in monocytes and lymphocytes (p ≤ 0.042). In conclusion, the intracellular stress protein response to 90 min interval exercise is closely related in monocytes and lymphocytes, and HSP32 appears to be attenuated with a pre-exercise alkalosis.     

Conversion of NaHCO3 to Na2CO3 with a growth of Arthrospira platensis cells in 660 m2 raceway ponds with a CO2 bicarbonation absorber

The weight ratio of Na₂CO₃/NaHCO₃ was investigated in order to improve microalgal productivity in large-scale industrial operations by converting NaHCO₃ to Na₂CO₃ with a growth of Arthrospira platensis cells in 660 m² raceway ponds. Two microalgal cultivation systems with a NaHCO₃ by-product (SPBP) and a CO₂ bicarbonation absorber (CBAP) were firstly thoroughly introduced. There was a 13.3% decrease in the initial weight ratio of Na₂CO₃/NaHCO₃ resulting in a 25.3% increase in the biomass growth rate with CBAP, compared to that of SPBP. Increased sunlight intensity, solution temperature and pH all resulted in both a higher absorbance and release, thereby increasing the weight ratio of Na₂CO₃/NaHCO₃ during the growth of A. platensis. The biomass growth rate was peaked at 39.9 g m⁻² day⁻¹ when the weight ratio of Na₂CO₃/NaHCO₃ was 3.7. Correspondingly, the cell pigments (chlorophyll a and carotenoid) and trichome size (helix pitch and trichome length) reached to a maximum state of 8.47 mg l⁻¹, 762 μg l⁻¹, 57 and 613 μm under the CBAP system.     

Functional expression of a novel alkaline-adapted lipase of Bacillus amyloliquefaciens from stinky tofu brine and development of immobilized enzyme for biodiesel production

Using enrichment procedures, a lipolytic strain was isolated from a stinky tofu brine and was identified as Bacillus amyloliquefaciens (named B. amyloliquefaciens Nsic-8) by morphological, physiological, biochemical tests and 16S rDNA sequence analysis. Meanwhile, the key enzyme gene (named lip _BA) involved in ester metabolism was obtained from Nsic-8 with the assistance of homology analysis. The novel gene has an open reading frame of 645 bp, and encodes a 214-amino-acid lipase (Lip_BA). The deduced amino acid sequence shows the highest identity with the lipase from B. amyloliquefaciens IT-45 (NCBI database) and belongs to the family of triacylglycerol lipase (EC 3.1.1.3). The lipase gene was expressed in Escherichia coli BL21(DE3) using plasmid pET-28a. The enzyme activity and specific activity were 250 ± 16 U/ml and 1750 ± 153 U/mg, respectively. The optimum pH and temperature of the recombinant enzyme were 9.0 and 40 °C respectively. Lip_BA showed much higher stability under alkaline conditions and was stable at pH 7.0–11.0. The Km and Vmax values of purified Lip_BA using 4-nitrophenyl palmitate as the substrate were 1.04 ± 0.06 mM and 119.05 ± 7.16 μmol/(ml min), respectively. After purification, recombinant lipase was immobilized with the optimal conditions (immobilization time 3 h at 30 °C, with 92 % enzyme recovery) and the immobilized enzyme was applied in biodiesel production. This is the first report of the lipase activity and lipase gene obtained from B. amyloliquefaciens (including wild strain and recombinant strain) and the recombinant Lip_BA with the detailed enzymatic properties. Also the preliminary study of the transesterification shows the potential value in biodiesel production applications.     

Loss of plant biodiversity eliminates stimulatory effect of elevated CO2 on earthworm activity in grasslands

Earthworms are among the world’s most important ecosystem engineers because of their effects on soil fertility and plant productivity. Their dependence on plants for carbon, however, means that any changes in plant community structure or function caused by rising atmospheric CO₂ or loss of plant species diversity could affect earthworm activity, which may feed back on plant communities. Production of surface casts measured during three consecutive years in field experimental plots (n = 24, 1.2 m²) planted with local calcareous grassland species that varied in plant species richness (diversity levels: high, 31 species; medium, 12; low, 5) and were exposed to ambient (356 μl CO₂ l^?1) or elevated (600 μl CO₂ l^?1) CO₂ was only consistently stimulated in high diversity plots exposed to elevated CO₂ (+120 %, 31 spp: 603 ± 52 under ambient CO₂ vs. 1,325 ± 204 g cast dwt. m^?2 year^?1 under elevated CO₂ in 1996; +77 %, 940 ± 44 vs. 1,663 ± 204 g cast dwt. m^?2 year^?1 in 1998). Reductions in plant diversity had little effect on cast production in ecosystems maintained at ambient CO₂, but the stimulatory effect of elevated CO₂ on cast production disappeared when plant species diversity was decreased to 12 and 5 species. High diversity plots were also the only communities that included plant species that an earlier field study showed to be among the most responsive to elevated CO₂ and to be most preferred by earthworms to deposit casts near. Further, the +87 % CO₂-induced increase in cast production measured over the 3 years corresponded to a parallel increase in cumulative total nitrogen of 5.7 g N m^?2 and would help explain the large stimulation of aboveground plant biomass production observed in high-diversity communities under elevated CO₂. The results of this study demonstrate how the loss of plant species from communities can alter responses of major soil heterotrophs and consequently ecosystem biogeochemistry.     

Elevated CO2 temporally enhances phosphorus immobilization in the rhizosphere of wheat and chickpea

Aims

The efficient management of phosphorus (P) in cropping systems remains a challenge due to climate change. We tested how plant species access P pools in soils of varying P status (Olsen-P 3.2–17.6 mg?kg^?1), under elevated atmosphere CO₂ (eCO₂).

Methods

Chickpea (Cicer arietinum L.) and wheat (Triticum aestivum L.) plants were grown in rhizo-boxes containing Vertosol or Calcarosol soil, with two contrasting P fertilizer histories for each soil, and exposed to ambient (380 ppm) or eCO₂ (700 ppm) for 6 weeks.

Results

The NaHCO₃-extractable inorganic P (Pi) in the rhizosphere was depleted by both wheat and chickpea in all soils, but was not significantly affected by CO₂ treatment. However, NaHCO₃-extractable organic P (Po) accumulated, especially under eCO₂ in soils with high P status. The NaOH-extractable Po under eCO₂ accumulated only in the Vertosol with high P status. Crop species did not exhibit different eCO₂-triggered capabilities to access any P pool in either soil, though wheat depleted NaHCO₃-Pi and NaOH-Pi in the rhizosphere more than chickpea. Elevated CO₂ increased microbial biomass C in the rhizosphere by an average of 21 %. Moreover, the size in Po fractions correlated with microbial C but not with rhizosphere pH or phosphatase activity.

Conclusion

Elevated CO₂ increased microbial biomass in the rhizosphere which in turn temporally immobilized P. This P immobilization was greater in soils with high than low P availability.     

Fed-Batch Cultivation of Arthrospira platensis Using Carbon Dioxide from Alcoholic Fermentation and Urea as Carbon and Nitrogen Sources

To reduce CO₂ emissions from alcoholic fermentation, Arthrospira platensis was cultivated in tubular photobioreactor using either urea or nitrate as nitrogen sources at different light intensities (60 μmol m^?2 s^?1?≤?I?≤?240 μmol m^?2 s^?1). The type of carbon source (pure CO₂ or CO₂ from fermentation) did not show any appreciable influence on the main cultivation parameters, whereas substitution of nitrate for urea increased the nitrogen-to-cell conversion factor (Y _X/N ), and the maximum cell concentration (X _m ) and productivity (P _X ) increased with I. As a result, the best performance using gaseous emissions from alcoholic fermentation (X _m ?=?2,960?±?35 g m^?3, P _X ?=?425?±?5.9 g m^?3 day^?1 and Y _X/N ?=?15?±?0.2 g g^?1) was obtained at I?=?120 μmol m^?2 s^?1 using urea as nitrogen source. The results obtained in this work demonstrate that the combined use of effluents rich in urea and carbon dioxide could be exploited in large-scale cyanobacteria cultivations to reduce not only the production costs of these photosynthetic microorganisms but also the environmental impact associated to the release of greenhouse emissions.     

Effects of Silicon on Osteoblast Activity and Bone Mineralization of MC3T3-E1 Cells

Previous studies have reported that dietary silicon (Si) intake is positively associated with bone health including bone mineral density. Although the amount of Si intake is high among trace elements in humans, how dietary Si affects bone formation at the cellular level is not well addressed. The purpose of this study was to investigate the role of Si in osteoblast activity and bone mineralization. MC3T3-E1 was cultured as mature osteoblasts and treated with sodium metasilicate (0, 1, 5, 10, 25, 50, and 100 μM) as a source of Si. After 7 days of treatment, 5 and 10 μM of sodium metasilicate significantly increased intracellular alkaline phosphatase activity (p?相似文献   

燕麦对松嫩草地三种主要盐分胁迫的生理适应策略

为明确燕麦幼苗对松嫩盐碱草地3种主要盐分Na Cl、Na HCO_3和Na_2CO_3的适应机制,设定不同浓度梯度(48—144 mmol/L)的胁迫处理液,测定燕麦幼苗的生长与生理指标变化。结果表明,尽管试验设定的Na Cl浓度并不影响幼苗的存活率,但在各组胁迫处理下,随着浓度的增加,燕麦幼苗的分蘖数、植株高度、茎叶与根系的生物量均呈下降趋势,下降幅度为Na_2CO_3Na HCO_3Na Cl。另外,与Na Cl胁迫相比,Na_2CO_3与Na HCO_3胁迫下茎叶与根中积累了更多的有毒Na~+,同时K~+下降幅度也更大,并且根系中含有更高的Na~+与更低的K~+以及更高的Na~+/K~+。在Na Cl胁迫下,燕麦幼苗积累大量的无机Cl~-和脯氨酸来维持细胞内的渗透与离子平衡,而Na HCO_3与Na_2CO_3胁迫造成了燕麦幼苗体内阴离子的亏缺,此时幼苗主要通过积累大量的有机酸和更多的脯氨酸来维持渗透与离子平衡。上述结果表明,碱性盐Na_2CO_3与Na HCO_3对植物的胁迫伤害程度大于中性盐Na Cl,并且Na_2CO_3的毒害效应最强,而燕麦幼苗对不同的盐分胁迫伤害也有会产生不同的生理适应策略。     

Photosynthetic refixing of CO2 is responsible for the apparent disparity between mitochondrial respiration in the light and in the dark

The net photosynthetic rate (P _N), the sample room CO₂ concentration (CO₂S) and the intercellular CO₂ concentration (C _i) in response to PAR, of C₃ (wheat and bean) and C₄ (maize and three-colored amaranth) plants were measured. Results showed that photorespiration (R _p) of wheat and bean could not occur at 2 % O₂. At 2 % O₂ and 0 μmol mol^?1 CO₂, P _N can be used to estimate the rate of mitochondrial respiration in the light (R _d). The R _d decreased with increasing PAR, and ranged between 3.20 and 2.09 μmol CO₂ m^?2 s^?1 in wheat. The trend was similar for bean (between 2.95 and 1.70 μmol CO₂ m^?2 s^?1), maize (between 2.27 and 0.62 μmol CO₂ m^?2 s^?1) and three-colored amaranth (between 1.37 and 0.49 μmol CO₂ m^?2 s^?1). The widely observed phenomenon of R _d being lower than R _n can be attributed to refixation, rather than light inhibition. For all plants tested, CO₂ recovery rates increased with increasing light intensity from 32 to 55 % (wheat), 29 to 59 % (bean), 54 to 87 % (maize) and 72 to 90 % (three-colored amaranth) at 50 and 2,000 μmol m^?2 s^?1, respectively.     

Purification and characterization of trans-3-(4-methoxyphenyl) glycidic acid methyl ester hydrolyzing lipase from Pseudomonas aeruginosa

Enantiospecific lipase was purified from Pseudomonas aeruginosa MTCC 5113 and it was used for the hydrolysis of (±)-methyl trans-3(4-methoxyphenyl) glycidate, a key intermediate in the synthesis of cardiovascular drug, diltiazem. Enzyme from broth supernatant was precipitated with acetone and purified by anion exchange and gel filtration chromatography. The purified lipase was a homogenous protein having a molecular weight of 59.4 kDa as determined by SDS-PAGE. Isoelectric point was found to be approximately 5.5 after 2D electrophoresis. This organic solvent tolerant enzyme was found to be active in presence of EDTA, Tween-80 and β-mercaptoethanol whereas sodium dodecyl sulphate and dithiothreitol inhibited its activity. The K_m and V_max of the enzyme were 50 mM and 27.1 μmol/min mg, respectively using p-nitrophenyl palmitate as a substrate. The activity of lipase was confirmed by (±)-MPGM hydrolysis and zymography.     

Ecosystem respiration derived from 222Rn measurements on Rishiri Island, Japan

We evaluated the nighttime CO₂ flux (ecosystem respiration) on Rishiri Island, located at the northern tip of Hokkaido, Japan, from 2009 to 2011, by using the relationship between atmospheric ²²²Rn and CO₂ concentrations. The annual mean CO₂ flux was 1.8 μmol m^?2 s^?1, with a maximum monthly mean in July (4.6 ± 2.6 μmol m^?2 s^?1) and a broad minimum from December to March (0.33 ± 0.29 μmol m^?2 s^?1). The annual mean was comparable to fluxes at the JapanFlux sites in northern Japan. During the season of snow cover (mid-December to early April), the CO₂ flux was low (0.45 ± 0.43 μmol m^?2 s^?1). Total annual respiration was estimated at 679 ± 174 g cm^?2, about 8 % of which occurred during the season of snow cover.     

Change in the viscoelastic properties of agarose gel by HAp precipitation by osteoblasts cultured in an agarose gel matrix

The viscoelastic properties of cell-seeded agarose gel were measured as a function of culture time. Because the seeded cells, MC3T3-E1, were osteoblast-like cells, the system can be regarded as a model osteogenesis system. For all specimens the characteristic stress relaxation curve of agarose gel was observed—a large relaxation up to 10⁴ s followed by a gel plateau, where the former was attributed to molecular motion of polymer chains between two adjacent cross-links of the gel and the latter to the elasticity of the gel network. The viscoelasticity was quantified by fitting stress relaxation data to an empirical equation. The relaxation time and its distribution did not change with culture time. The initial and equilibrium moduli, E ₀ and E _e, respectively, and relaxation strength, ΔE = E ₀ ? E _e, did not change up to day 15 of culture but changed significantly at day 18 of culture. The change in ΔE with culture period correlated well with that in E ₀. The changes in the mechanical properties of the cell-seeded agarose gel system were explained in terms of the function of MC3T3-E1 in precipitating calcium phosphate mineral particles. The precipitation was detected by alizarin red S staining of the system at day 9 of culture. The precipitated calcium phosphate was confirmed to be hydroxyapatite (HAp) and the amount of HAp increased monotonically with culturing time, both of which were observed by X-ray diffraction studies. The dependence of the modulus of the composite on mineral fraction is discussed. A simple model of mixing of the components based on the continuum material concept was not applicable, but a model considering percolation of mineral particles in a network chain with culture time was suitable to explain the observed results. The results may be particularly important for predicting the stiffness of functionally engineered bony tissue implanted in a fractured bone.     

Biodegradation of para-nitrophenol by Citricoccus nitrophenolicus strain PNP1T at high pH

A gram-positive bacterium Citricoccus nitrophenolicus (strain PNP1^T, DSM 23311^T, CCUG 59571^T) isolated from a waste water treatment plant was capable of effectively degrading p-nitrophenol (pNP) as a source of carbon, nitrogen and energy for growth. Degradation of pNP required oxygen and resulted in the stoichiometric release of nitrite. Strain PNP1^T also degraded 4-chlorophenol, phenol and salicylate. pNP was degraded at pH values between 6.8 and 10.0 and at temperatures between 15–32 °C. pNP at concentrations up to 150 mg L^?1 were degraded during growth in media at pH ≤ 10, whereas 200 mg L^?1 was completely inhibitory to growth. When incubated in an NH₄Cl-free medium (pH 10) containing both pNP and acetate, pNP is degraded with concomitant release of nitrite which was subsequently assimilated during acetate degradation. Intact cells of strain PNP1^T suspended in NaHCO₃/Na₂CO₃ buffer were able to continuously degrade 200 mg L^?1 pNP over a 40 day period at pH 10.     

Temporal patterns of soil CO2 efflux in a temperate Korean Larch (Larix olgensis Herry.) plantation, Northeast China

There is little information available regarding seasonal and annual variations in soil CO₂ efflux from Korean Larch plantations, which are an important component of forests’ carbon balance in temperate China. In this study, the soil respiration rate (R _s), soil temperature (T ₁₀) and soil moisture (SM₁₀) at 10 cm depth were observed in a Korean Larch (Larix olgensis Herry.) plantation in Northeast China from 2008 to 2012. Mean R _s in growing season (GS) varied greatly, ranged from 2.32 ± 0.08 to 3.88 ± 0.09 μmol CO₂ m^?2 s^?1 (mean ± SE) over the period of 2008–2012. In comparison with T-model, the increase of explained variability by applying both T ₁₀ and SM₁₀ to the T-M model is very small. It is indicated that R _s was controlled largely by T ₁₀ in the present study. By accounting for 22.2 and 17.7 % of the total soil CO₂ emissions in 2010/2011 and 2011/2012, respectively, the soil CO₂ efflux in dormant season (DS) was an essential component of the total soil CO₂ efflux. The Q ₁₀ value in the study period was always smaller for GS than DS, suggesting that soil carbon cycling may be more sensitive to the temperature changes at low than at high temperature range. These results indicated that climate changes may have great potential impacts on temperate Larch plantations in Northeast China, owing to soil carbon emissions of Larch plantation during the long period of DS being more sensitive to T ₁₀ than in GS, and played a significant role in the annual forest ecosystems carbon budget.     

Comparison of organ cultured precut corneas versus surgeon-cut corneas for Descemet’s stripping automated endothelial keratoplasty

To compare precut and surgeon-cut organ cultured donor corneas for DSAEK. A total of 119 consecutive eyes treated with DSAEK were retrospectically identified. 65 grafts were cut by the surgeon (Moria, ALTK System) prior to DSAEK and 54 grafts were precut by laboratory technicians from the Danish Eye Bank (Horizon single-use system). 1 year after surgery, tomographic images were obtained with the Pentacam HR. Endothelial cell density (ECD) and best-corrected visual acuity (BCVA) was determined. Graft thickness and graft asymmetry was evaluated in the centre and 1 mm from the edge of the graft in 6 semi-meridians. 1 year after surgery, the ECD loss was similar in the two groups, averaging 25.9 ± 14 % in surgeon-cut, and 22.9 ± 17 % in precut group (p = 0.33). Mean central graft thickness was 172 ± 6 μm in surgeon-cut grafts and 182 ± 6 μm in precut grafts (p = 0.30). BCVA was similar in surgeon-cut and precut corneas; being 0.25 ± 0.02 logMAR and 0.24 ± 0.02 logMAR, respectively (p = 0.59). The graft asymmetry index was 1.48 ± 0.02 for surgeon-cut and 1.44 ± 0.02 for precut grafts. There were no significant differences in complications rate in both groups. No correlations between BCVA and central graft thickness or graft asymmetry index in both groups were observed. Organ cultured precut donor corneas are comparable with surgeon-cut grafts with respect to ECD, graft thickness and asymmetry, and postoperative complication rate.     

Inorganic carbon and pH effect on growth and lipid productivity of Tetraselmis suecica and Chlorella sp (Chlorophyta) grown outdoors in bag photobioreactors

There has been considerable interest in cultivation of green microalgae (Chlorophyta) as a source of lipid that can alternatively be converted to biodiesel. However, almost all mass cultures of algae are carbon-limited. Therefore, to reach a high biomass and oil productivities, the ideal selected microalgae will most likely need a source of inorganic carbon. Here, growth and lipid productivities of Tetraselmis suecica CS-187 and Chlorella sp were tested under various ranges of pH and different sources of inorganic carbon (untreated flue gas from coal-fired power plant, pure industrial CO₂, pH-adjusted using HCl and sodium bicarbonate). Biomass and lipid productivities were highest at pH 7.5 (320?±?29.9 mg biomass L^?1 day^?1and 92?±?13.1 mg lipid L^?1 day^?1) and pH 7 (407?±?5.5 mg biomass L^?1 day^?1 and 99?±?17.2 mg lipid L^?1 day^?1) for T. suecica CS-187 and Chlorella sp, respectively. In general, biomass and lipid productivities were pH 7.5?>?pH 7?>?pH 8?>?pH 6.5 and pH 7?>?pH 7.5?=?pH 8?>?pH 6.5?>?pH 6?>?pH 5.5 for T. suecica CS-187 and Chlorella sp, respectively. The effect of various inorganic carbon on growth and productivities of T. suecica (regulated at pH?=?7.5) and Chlorella sp (regulated at pH?=?7) grown in bag photobioreactors was also examined outdoor at the International Power Hazelwood, Gippsland, Victoria, Australia. The highest biomass and lipid productivities of T. suecica (51.45?±?2.67 mg biomass L^?1 day^?1 and 14.8?±?2.46 mg lipid L^?1 day^?1) and Chlorella sp (60.00?±?2.4 mg biomass L^?1 day^?1 and 13.70?±?1.35 mg lipid L^?1 day^?1) were achieved when grown using CO₂ as inorganic carbon source. No significant differences were found between CO₂ and flue gas biomass and lipid productivities. While grown using CO₂ and flue gas, biomass productivities were 10, 13 and 18 %, and 7, 14 and 19 % higher than NaHCO₃, HCl and unregulated pH for T. suecica and Chlorella sp, respectively. Addition of inorganic carbon increased specific growth rate and lipid content but reduced biomass yield and cell weight of T. suecica. Addition of inorganic carbon increased yield but did not change specific growth rate, cell weight or content of the cell weight of Chlorella sp. Both strains showed significantly higher maximum quantum yield (F_v/F_m) when grown under optimum pH.     

Optimisation of biomass and lipid production by adjusting the interspecific competition mode of Dunaliella salina and Nannochloropsis gaditana in mixed culture

The high cost of algal cultivation has been a barrier associated with the commercialisation of algal biodiesel. Therefore, this study aimed to enhance lipid production by optimising the nutrient supply to benefit the coexistence of Dunaliella salina and Nannochloropsis gaditana. The effects on biomass and lipid production of using different proportions of D. salina and N. gaditana, urea and NaHCO₃ were optimised by response surface method with a 17-run Box–Behnken design. The optimal conditions for the algal growth are 58 % of D. salina in the mixture at OD₆₈₀, 150 μL day^?1 urea (0.0044 g day^?1) and no addition of NaHCO₃. The biomass concentration and lipid production reached 1.00 and 0.383 g L^?1, respectively, which are exceeded by the amount before optimisation, indicating the efficiency of the model obtained by response surface method.