Terms Of Cell Density Research Articles

Acidithiobacillus ferrooxidans Leaching of Silica-Sulfide Gold Ores from May-Hibey Deposits, Tigray, Ethiopia

Oxidative leaching is an inexpensive alternative to using chemical cyanide extraction methods for gold from low-grade gold sulfide. Oxidation of finely ground gold-bearing ore by Acidithiobacillus ferrooxidans was evaluated in terms of cell density, pH, and leaching efficiency of Fe and Au in shake flask experiments. The compositional and elemental analyses of the beneficiated ore were analyzed using XRD and EDXRF spectroscopy. The ore’s primary constituents are gold (4.356 mg/L), silicon, iron, and sulfur (62.456, 15.441, and 7.912 wt%, respectively). XRD spectra, the main phases of the concentrated ore, showed that the major components of the ore were quartz, syn, silicon sulfide, pyrite, and polymetallic elements such as silderenrite, gismondine, siderenikite, hematite, and syn. The experimental results, with Acidithiobacillus ferrooxidans bacteria and blank, were evaluated. The pH of the blank remained nearly constant, and the pH of the bioleached was occasionally lowered. The A. ferrooxidans strain always grew better throughout the bioleaching process. For the A. ferrooxidans strain, the cell density of cells reached a maximum of 90.00 × 106 cells/mL after the 11th week and decreased to 87.00 × 106 cells/mL after the 12th week. The decrease in cell density may be due to the presence of polymetallic elements such as Al, Cr, Ti, and Ni, leading to reduced metal tolerance of the A. ferrooxidans strain. In the A. ferrooxidans leaching process, the maximum total iron and gold extraction reached 92.16% (14.23 mg/L) and 99.97% (4.355 ppm), respectively, after the 11th week, and leaching tends to decrease up to 14 weeks, which may be due to the formation of secondary minerals. More research will be performed to optimize the procedure and leaching kinetic, examine the impact of metal content, and take into account the potential for bioleaching process pollution in addition to the amount of gold recovered.

Sequential adaptation to serum-free medium for Vero cells cultivation on ultraviolet/ozone (UVO) treated microcarrier

The adoption of serum-free media (SFM) in cell culture has gained prominence as an alternative to serum-supplemented media (SSM) owing to concerns regarding serum variability and quality assurance. Vero cells, widely utilized in viral vaccine production for their susceptibility to various viruses, were the focus of this study. Our primary objective was to adapt Vero cells from SSM to SFM and subsequently upscale the culture from T-flasks to spinner vessels using ultraviolet/ozone (UVO) treated polystyrene (PS) and polycaprolactone (PCL) microcarriers. Cell counting was conducted via haemocytometer and inverted phase microscopy. The results indicated that SFM-adapted Vero cells achieved higher maximum cell concentrations compared to those cultured in SSM, along with a shorter doubling time. However, during cultivation in spinner vessels, Vero cells exhibited lower maximum cell concentrations compared to T-flask cultures, attributed to factors such as cell inoculum size and microcarrier hydrophilicity. This study highlights the successful adaptation of Vero cells to SFM and the potential benefits in terms of cell density and growth kinetics. Furthermore, it sheds light on the challenges encountered during culture upscale, offering valuable insights for optimizing future large-scale production processes. The findings contribute to the advancement of serum-free cell culture systems and their applicability in the production of viral vaccines.

Poly(ε-Caprolactone) Substrates with Micro/Nanohierarchical Patterned Structures for Cell Culture.

A simple, efficient and controllable one-step template method is proposed to fabricate poly(ε-caprolactone) substrates with micro/nanohierarchical patterned structures. Two kinds of geometric patterns with and without nanowires, i.e., hexagonal and strip with controllable island size and spacing are designed and fabricated. Furthermore, the influence of geometric patterns, island size, island spacing, and patterned nanowires (pNW) on the growth behavior of MG-63 cells is studied in terms of cell density, distribution, proliferation, morphogenesis, and cellular alignment. It is found that MG-63 cells prefer to adhere and grow on the substrate with smaller island size or spacing. Moreover, unlike the hexagonal structure, the strip structure can guide cellular alignment on its surface. In addition, the microisland structures and the pNW play different roles in promoting cell proliferation, distribution, and morphogenesis. It is concluded that the growth behavior of MG-63 cells can be well controlled by precisely adjusting the micro/nanostructure of the substrate surface. A simple and effective method is provided here for the regulation of cell growth behavior.

Effects of different culture media on the growth and proximate composition of Dunaliella sp. at different growth phase

Nutrient content in different culture media significantly influence the growth and proximate content of microalgae. Therefore, in the present study Dunaliella sp. has been selected to determine its growth and proximate composition in different growth phase in Conway and F2 media. For growth determination, data were collected in terms of cell density and optical density and harvested in every growth phases to determine its proximate composition. Results concluded that, Dunaliella sp. showed higher cell density and earlier stationary phase in F2 medium with 7.8 x 106 cells mL-1 compared to the Conway media with 4.1 x 106 cells mL-1 . Significantly higher (p>0.05) amount of protein content was recorded from Conway media in log phase with 67.58 % dry weight followed by lag and stationary phase with 57.53 % and 51.1 % dry weight. On the other hand, Dunaliella sp. showed no significant different (p>0.05) in carbohydrate content at different growth phase but followed an increasing pattern with the growth of microalgae. Stationary phase showed the highest amount of carbohydrate compared with other phases with 19.78 % in Conway media and 23.93 % in F2 medium. Conway media resulted significantly higher (p>0.05) lipid content compared to F2 medium. In lag, log and stationary phase 12.90 %, 9.80 % and 9.05 % of lipid were found in Conway media. This information might contribute to boost up the microalgal production by using the suitable culture media and can harvest the microalgae at different growth phases at their highest specific nutrient.

Effects of sodium nitrate on the growth and proximate composition of the indigenous marine microalgae Tetraselmis chuii (Butcher, 1959)

Nitrogen is one of the fundamental nutrients for algal growth, underpinning the microalgal biochemical composition. Therefore, this study compared the growth and proximate compositions of Tetraselmis chuii (Butcher, 1959), cultured in different nitrate (NaNO3 ) concentrations (25, 50, 100, 200 and 500 mg L-1). Thus, the cell density, optical density, specific growth rate and division rate of T. chuii were measured daily. Furthermore, protein and carbohydrate contents were also determined in the stationary phase. The results showed that T. chuii cultivated in a NaNO3 concentration of 500 mg L-1 had significantly (p<0.05) higher growth in terms of cell density, biomass, optical density, specific growth rate and division rates compared with other concentrations. Likewise, protein content was also significantly higher under the NaNO3 concentration of 500 mg L-1, whereas significantly (p<0.05) higher carbohydrate content was found at 25 mg L-1 NaNO3 compared with the other concentrations, showing a contrary trend between protein and carbohydrate concentrations, respectively. Since the primary focus has been on improving the quality of microalgal biomass in order to develop novel processes and products, this is the first study to use higher concentrations of modified nitrate on T. chuii isolated from the coastal area of Bangladesh. Thus the indigenous marine T. chuii had significantly utilised NaNO3 concentrations with higher growth and proximate contents in this study. However, further study is needed on microalgal genetics and metabolic engineering to create a new molecular era of the indigenous marine microalgae isolated from the coastal water of Bengal. 

Dental follicle cell differentiation towards periodontal ligament-like tissue in a self-assembly three-dimensional organoid model.

Periodontitis remains an unsolved oral disease, prevalent worldwide and resulting in tooth loss due to dysfunction of the periodontal ligament (PDL), a tissue connecting the tooth root with the alveolar bone. A scaffold-free three-dimensional (3D) organoid model for in vitro tenogenesis/ligamentogeneis has already been described. As PDL tissue naturally arises from the dental follicle, the aim of this study was to investigate the ligamentogenic differentiation potential of dental follicle cells (DFCs) in vitro by employing this 3D model. Human primary DFCs were compared, in both two- and three-dimensions, to a previously published PDL- hTERT cell line. The 3D organoids were evaluated by haematoxylin and eosin, 4',6-diamidino-2-phenylindole and F-actin staining combined with detailed histomorphometric analyses of cell-row structure, angular deviation and cell density. Furthermore, the expression of 48 tendon/ligament- and multilineage-related genes was evaluated using quantitative polymerase chain reaction, followed by immunofluorescent analyses of collagen 1 and 3. The results showed that both cell types were successful in the formation of scaffold-free 3D organoids. DFC organoids were comparable to PDL-hTERT in terms of cell density; however, DFCs exhibited superior organoid morphology, cell-row organisation (p < 0.0001) and angular deviation (p < 0.0001). Interestingly, in 2 dimensions as well as in 3D, DFCs showed significantly higher levels of several ligament- related genes compared to the PDL-hTERT cell line. In conclusion, DFCs exhibited great potential to form PDL-like 3D organoids in vitro suggesting that this strategy can be further developed for functional PDL engineering.

Cultivation of Chlorella vulgaris in aquaculture wastewater as alternative nutrient source and better treatment process

Together with the fastest growing of aquaculture production, aquaculture industry also produces a large amount of wastewater that results in not only eutrophication of waterbody but also increases the aquaculture cost and threatening global sustainability. To overcome those barriers in the aquaculture industry, application of microalgae for wastewater remediation, biomass production to produce value added products, and water quality control have been devoted as microalgae assimilate nutrients in a eutrophic water body and a good way for wastewater remediation. The objective of this study was to determine the growth and nutritional profile of Chlorella vulgaris culture in different percentage of aquaculture wastewater (ww) in combination with Conway media. For the experiment, C. vulgaris was cultivated in different wastewater concentration such as 25% ww + 75% Conway media (T2); 50% ww + 50% Conway media (T3); 75% ww + 25% Conway media (T4); 100% ww (T5) and 100% Conway media, considered as control (T1). The results of this study showed that the growth of C. vulgaris, in terms of cell density and optical density were maximum at day 5 in T3 (50% wastewater) and was significantly (p &gt; 0.05) higher (4.33x106 cellsml-1 ) (0.400 Abs) compared to the other treatments. Highest amount of protein content was found in Conway media (T1) (42.69 % dry weight) whereas lipid content was highest in 100 % ww (17 % dry weight) and then in 75 % ww treatment (16 % dry weight) and carbohydrate content was maximum in T3 treatment (24 % dry weight) which were significantly higher (p &gt; 0.05) then the other treatments. The study indicates that media enriched with aquaculture wastewater can enhance the cell growth and nutrient values of C. vulgaris which is a cost effective and environment friendly approach to minimize aquaculture waste loading in water body.

Relationship between the bacterial community structures on human hair and scalp.

In this study, we investigated and compared characteristics of the bacterial community structures on hair (scalp hair) and scalp in 18 individuals. Significant differences were found between the sites, in terms of cell density, alpha and beta diversity, and relative abundance of the phyla, Firmicutes and Proteobacteria, whereas no difference was found in relative abundance of the phylum Actinobacteria. Bacteria of the genus Cutibacterium showed similar relative abundance at both sites, whereas those of genus Pseudomonas were highly abundant on hair, and those of genus Staphylococcus were significantly lesser in abundance on hair than on scalp. Statistical correlations between the sites were high for the individual relative abundance of five major operational taxonomic units (OTUs). This suggests that the bacterial community structure on hair is composed of hair-specific genus, Pseudomonas, and skin-derived genera, Cutibacterium and Staphylococcus, and is distinguishable from other human skin microbiomes.

Laboratory-scale evaluation of algaecide effectiveness for control of microcystin-producing cyanobacteria from Lake Okeechobee, Florida (USA)

Growth of microcystin-producing cyanobacteria in Lake Okeechobee (Florida, USA) and surrounding waters has resulted in adverse health impacts for humans and endangered species, as well as significant economic losses. As these issues worsen, there is growing pressure for efficacious solutions to rapidly mitigate harmful algal blooms (HABs) and protect critical freshwater resources. Applications of USEPA-registered algaecides as management tactics meet many decision-making criteria often required by water resource managers (e.g., effective, scalable, selective), but have not yet been evaluated on a large scale within the Lake Okeechobee waterway. This study was conducted to bolster the peer-reviewed database for available management tactics against microcystin-producing cyanobacteria in waters of this region. Laboratory-scale experiments can be conducted first to minimize uncertainty at larger scales and improve confidence in decision-making. In this study, samples containing microcystin-producing cyanobacteria collected from Lake Okeechobee were exposed to several USEPA-registered algaecides in laboratory toxicity experiments. Responses of target cyanobacteria were measured 3 days after treatment (DAT) in terms of cell density, chlorophyll-a concentrations, and phycocyanin concentrations. Based on responses of the cyanobacteria, minimum effective exposure concentrations were identified for each algaecide. Microcystin release (i.e. proportion of total microcystins in the aqueous phase) was measured and compared 1 DAT among effective exposures. Total microcystin concentrations were measured in effective treatments at 1, 4, and 9 DAT to discern potential for microcystin persistence following exposures to the effective formulations and exposure concentrations. Overall, several formulations including GreenClean Liquid® 5.0, GreenClean Liquid® 5.0 combined with Hydrothol® 191, and the copper-based algaecides evaluated (Algimycin® PWF, Argos, Captain® XTR, Cutrine® Ultra, and SeClear®) achieved significant and similar effects on target cyanobacteria. The chelated copper-based formulations (Algimycin® PWF, Argos, Captain® XTR, and Cutrine® Ultra) resulted in relatively less microcystin release 1 DAT and lesser total microcystin concentrations 4 DAT. At 9 DAT, total microcystin concentrations were significantly lower than in untreated controls in all treatments evaluated. These results provide the necessary comparative performance data for preliminary decision-making and designing additional studies at larger scales. Importantly, the comparative toxicity data and approach provided in this study demonstrate the initial steps for development of site-specific management strategies for Lake Okeechobee and other areas impacted by harmful algal blooms with large spatial and temporal scales.

Growth, lipid content, and fatty acid profile of freshwater cyanobacteria Dolichospermum affine (Lemmermann) Wacklin, Hoffmann, &amp; Komárek by using modified nutrient media

In this study, Dolichospermum affine was cultivated under starvation and limitation conditions, using six different concentrations of nitrate (NaNO3) and phosphate (K2HPO4) in BG-11 medium. The biomass, pigments, proteins, carbohydrates, lipids, triacylglycerol-TAG, and fatty acid responses to different modified media were examined in terms of cell density, dry biomass, optical density, growth rate, chlorophyll-a, carotene content, and lipid productivity. Molecular characterization of D. affine isolates was performed using Fourier transform–infrared spectroscopy (FT-IR) and polymerase chain reaction (PCR). In the 20-day batch culture period, one of the modified media, %50 N and P limitation (N-PLimitation), exhibited higher values than the others in terms of cell density (1.41 × 107 cells/mL), dry biomass (1.68 gL−1), optical density (1.26), growth rate (0.48 day−1), chlorophyll-a (3.76 μg L−1), and total carotenoid (12.99 μg L−1). The maximum percentage lipid content of D. affine was obtained in the control group at 10.67%. Fatty acid profiles have been investigated in six conditions and consisted of 10 fatty acids. The basic saturated fatty acid palmitic acid was (C16:0) for all conditions, and its rate was 40.61% for starvation of N and P (N-PDeprivation) conditions. Oleic acid (C18:1) rate was detected in all groups, but the highest rate was found in the control group with 33.72%. In all conditions, TAG values were found similar, but the highest value was determined at 50% P and 100% N (PLimitation-NControl) (27.5%) modified media. Carbohydrate content (20.37%) was found to be high under N and P starvation (N-PDeprivation), while protein content (66.92%) was high under 50% N and 100% P (NLimitation-PControl) conditions. The results obtained from this study showed that nitrogen and phosphorus starvation and limitation affecting the biomass, valuable secondary metabolites and lipid accumulation and affected the fatty acid composition of D. affine cultures.

Enhancing the Lifetime of a Phase Change Memory with Bit-Flip Reversal

Phase Change Memory (PCM) has evolved as a promising alternative over Dynamic Random Access Memory (DRAM) in terms of cell density and leakage power. While non-volatility is a desirable feature, it gives rise to the possibility of the data being present even after the power is switched off. To secure the data, encryption is normally done by using the standard Advanced Encryption Standard (AES) algorithm. Encrypting the data results in huge number of bit-flips, which reduces the lifetime of a PCM. The proposed method increases the lifetime of PCM by reducing the number of bit-flips occurred due to the encryption of modified words only and leaving the unmodified words as they are. The generated encrypted text, which is written by using the bit-flips reversal method, reduces the number of cells involved in writing by approximately 25%. This method is implemented by using Gem5 simulator and is evaluated with splash2 benchmark suite. It is observed that the proposed method improves the lifetime of a PCM memory by 15% without consuming extra power.

Cell density, Lipidomic profile, and fatty acid characterization as selection criteria in bioprospecting of microalgae and cyanobacterium for biodiesel production

Selection of indigenous and potential algal strain with high lipid content is paramount challenge in the avenues of microalgal biodiesel production. Particularly, hyper lipid producing algae with maximal triacyglycerols (TAGs) content and preferable fatty acid composition is of interest for sustainable biodiesel. Hence, the present study on comparative assessment of Chlorella vulgaris, Scenedesmus sp. and Synechococcus sp. was done in terms of cell density, lipid, TAGs and fatty acid. Higher biomass yield was obtained in Chlorella vulgaris (0.54 gL−1) on 13th day while maximal lipid content of 36% was observed in Scenedesmus sp. followed by Chlorella vulgaris (33%). Lipidomic analysis revealed higher non-polar lipids inChlorella vulgaris (57%) and Scenedesmus sp. (54%), whereas in Synechococcus sp. 69% polar lipids were present. In fatty acid profile, C24:0 (22.11%) was predominant in Chlorella vulgaris, while C20:0 (31.72%) and C18:2 (22.26%) was prevalent in Scenedesmus sp. and Synechococcus sp. respectively.

Self-Driven Phase Transitions Drive Myxococcus xanthus Fruiting Body Formation.

Combining high-resolution single cell tracking experiments with numerical simulations, we show that starvation-induced fruiting body formation in Myxococcus xanthus is a phase separation driven by cells that tune their motility over time. The phase separation can be understood in terms of cell density and a dimensionless Péclet number that captures cell motility through speed and reversal frequency. Our work suggests that M. xanthus takes advantage of a self-driven nonequilibrium phase transition that can be controlled at the single cell level.

Recovery of landfill leachate as culture medium for two microalgae: Chlorella sp. and Scenedesmus sp.

The microalgae culture medium should contain essential nutrients for their optimal growth. However, landfill leachate contains these nutrients; merely, the use of leachate in the cultivation of microalgae is not conceivable because of its high toxicity. This survey proposes to demonstrate the growth performance in terms of biomass production, chlorophyll contents and cell morphology of two microalgae, namely Chlorella sp. and Scenedesmus sp., in different concentrations of leachate (10%, 30%, 50%, 80% and 100% (v/v) crude leachate). Changes in chemical oxygen demand (COD), ammoniacal nitrogen (NH4+–N) and salinity content were also monitored. Results showed that when the two algae were mixed, the culture medium containing 10% (v/v) of leachate caused an optimal and selective growth of Chlorella and a total mortality for Scenedesmus cells. Also, this culture medium containing 10% (v/v) of leachate promoted the cell growth of Chlorella sp., of around 2 times in terms of cell density and 10 times in terms of chlorophyll content as compared to the result obtained for the standard culture medium “Bold’s Basal Medium (BBM).” Abatement rates of COD, NH4+–N and salinity of 60%, 100% and 10% were, respectively, achieved by pure cultures of Chlorella sp. Therefore, the strain of Chlorella sp. appeared resistant in this unfriendly environment as compared to the strain of Scenedesmus sp. As a perspective, the tested landfill leachate could be convenient for culturing Chlorella sp. for leachate purification and biofuel production.

Comparative effects of seawater acidification on microalgae: Single and multispecies toxicity tests

In order to gain knowledge about the potential effects of acidification in aquatic ecosystems, global change research based on microalgae as sentinel species has been often developed. However, these studies are limited to single species tests and there is still a research gap about the behaviour of microalgal communities under this environmental stressor. Thus, the aim of this study was to assess the negative effects of CO2 under an ecologically realistic scenario. To achieve this objective, two types of toxicity tests were developed; i) single toxicity tests and ii) multispecies toxicity tests, in order to evaluate the effects on each species as well as the interspecific competition. For this purpose, three microalgae species (Tetraselmis chuii, Phaeodactylum tricornutum and Nannochloropsis gaditana) were exposed to two selected pH levels (7.4, 6.0) and a control (pH 8.0). The pH values were choosen for testing different scenarios of CO2 enrichment including the exchange atmosphere-ocean (pH 7.4) and natural or anthropogenic sources of CO2 (pH 6.0). The effects on growth, cell viability, oxidative stress, plus inherent cell properties (size, complexity and autofluorescence) were studied using flow cytometry (FCM). Results showed that T. chuii was the most resistant species to CO2 enrichment with less abrupt changes in terms of cell density, inherent cell properties, oxidative stress and cell viability. Although P. tricornutum was the dominant species in both single and multispecies tests, this species showed the highest decrease in cell density under pH 6.0. Effects of competence were recorded in the multispecies control (pH 8) but this competence was eclipsed by the effects of low pH. The knowledge of biological interactions made by different microalgae species is a useful tool to extrapolate research data from laboratory to the field.

Effect of Mixing on the Density and Chlorophyll A Content on Botryococcus Sp.

Optimization of the growth of microalgae is essential due to demand for high biomass yields. In addition, the methods to estimate the growth (as cell density or biomass) of microalgae are tedious. The normal methods include cell counts, optical density, chlorophyll a and ash free dry weight. However, at least two of these methods were done together for every growth experiment to get a better result. Therefore, this study investigates the effect of mixing as one of the many factors that determines the growth of microalgae, Botryococcus sp. In addition, three different methods to estimate the growth (in terms of cell density or biomass) will be utilized. Three different treatments on the effect of mixing were employed (T1 using aeration; T2 manual hand shake two times daily; T3 no aeration and shaking) for these experiments. The experiment was carried out under outdoor conditions with temperature ranging from 25.8°C to 35.5°C, light intensity from from 200 Lux to 18000 Lux and pH of 7 to 8 units for 24 days using Bold basal medium (BBM) as growth media. Microalgae biomass was estimated by optical density, chlorophyll a and cell count using haemocytometer. The highest density of Botryococcus sp. was achieved (10.74 x 106 cell ml-1day-1; OD of 3.246 at 680nm; 0.7843 mg L-1day-1 chlorophyll a) with aeration. Whereas, the lowest (2.78 x 106 cell ml-1day-1; od 1.007 (680nm); chlorophyll a 0.1586 mg L-1day-1) and (3.07 x 106 cell ml-1day-1; od 0.999 (680nm); chlorophyll a 0.1545 mg L-1day-1) with shaking and no aeration, respectively. There exist a positive linear relationship between cell counting and optical density (R2=0.96); cell count and chlorophyll a (R2=0.95); and optical density and chlorophyll a (R2= 0.98) were observed. The result of this study suggested that constant aeration is required by the microalgae, Botryococcus sp. for growth in terms of cell density and biomass.

Using Chlorella vulgaris to treat toxic excess sludge extract, and identification of its response mechanism by proteomics approach

Chlorella vulgaris was cultivated in varying proportions of toxic sludge extracts obtained from a sequencing batch reactor for treating synthetic wastewater containing chlorophenols. C. vulgaris could reduce the ecotoxicity from sludge extracts, and a positive correlation was noted between ecotoxicity removal and total organic carbon removal. In terms of cell density, the optimal proportion of sludge extracts required for the cultivation of C. vulgaris was lower than 50%. The correlation between protein content in per 106 algae and inhibition extent of ecotoxicity of the 5 groups on the day of inoculation (0.9182, p < .05) indicated a positive relationship between algal protein secretion and ecotoxicity. According to the protein expression and differential protein expression analysis, we concluded that C. vulgaris produced proteins that involved in the stress response/redox system and energy metabolism/biosynthesis to respond to the toxic environment and some other proteins related to mixotrophic metabolism.

Corneal endothelial cell density and morphology in rabbits’ eyes using contact specular microscopy

ABSTRACT: The goal of this study was to describe the normal values of corneal endothelial cell density and hexagonality in healthy rabbits’ eyes using contact specular microscopy. Both eyes of 18 rabbits, males and females, of different ages were evaluated. The eyes were divided into three groups of 12 each according to the age range of the animals: G1 (6 months old), G2 (12 months old), and G3 (48 months old). Parameters studied included mean endothelial cell density and hexagonality. For Group I, the mean cell density was 2307 cells per mm2. For GII, the mean cell density was 1895 cells per mm2. For G III, the mean cell density was 1818 cells per mm2. Cell density decreased significantly with aging (P&lt;0.001) among the three groups. Pleomorphism in the rabbits of GI was 74.33±10.08. In the rabbits of GII it was 71.83±11.38. In the rabbits of GIII it was 64.02±28.80. Significant differences (P&lt;0.001) were evident between GI and GIII and GII and GIII but not between Groups I and II. The results showed a decrease in number of cells and hexagonality with aging. Corneal endothelium of rabbits suffers changes due to advancing age both in terms of cell density and morphology.

Efficiency and cytotoxicity analysis of cationic lipids-mediated gene transfection into AGS gastric cancer cells

In this effort, we provided comparative study on optimization of transfection conditions for AGS human gastric cancer cell line using two commercial non-liposomal cationic lipids. Using reporter vector pEGFP-N1, transfection efficiency of Attractene™ and X-tremeGENE HP™ transfection reagents in terms of cell densities and DNA/reagent ratios was determined in AGS cells by flow cytometry and fluorescence microscopy. In addition, influence of transfection reagents on direct cytotoxicity and cell viability was respectively, measured using lactate dehydrogenase (LDH) leakage and MTT assays. Provided that the transfection rate of 29% and the mean fluorescence intensity of 437.5, the DNA/reagent ratio of 0.4/1.5 was selected as the optimal condition using Attractene™, whereas the optimum condition using X-tremeGENE HP™ was obtained by the ratio of 1/2 with a higher transfection rate of 36.9% and an MFI of 833. Very low direct cytotoxicity (<5% and 6–9% using Attractene™ and X-tremeGENE HP™, respectively) and high cell viability (74.5–95.5% versus 68–75%) showed the biodegradable attribute for both transfection reagents. Altogether, X-tremeGENE HP™ exhibited superiority over Attractene™ as a transfection reagent for AGS cells. In the present research, we have established the optimized protocols for efficient transfection of AGS cells with potential applications in gene function and expression studies as well as gene therapy.

Use of light emitting diodes (LEDs) for enhanced lipid production in micro-algae based biofuels

Microalgae are an alternative source for renewable energy to overcome the energy crises caused by exhaustion of fuel reserves. Algal biofuel technology demands a cost effective strategy for net profitable productivity. Inconsistent illumination intensities hinder microalgal growth. The light-utilizing efficiency of the cells is critical. Light scarcity leads to low production and high intensities cause photo-inhibition. We report effective usage of LEDs of different band wavelengths on the growth of microalgae in a closed, controlled environment to generate biomass and lipid yields. Among the different intensity and wavelengths tested. The light intensities of 500lx of blue-red combination gave maximum biomass in terms of cell density. LED of red light 220lx wavelength doubled the lipid dry weight from 30% (w/w) in white light to 60% (w/w). Thin layer lipid chromatogram demonstrated a dense and prominent spot of triacylglycerols in the red light, 220lx grown cultures. The FTIR profile indicates that different wavelength exposure did not alter the functional groups or change the chemical composition of the extracted lipids ensuring the quality of the product. We reiterate the fact that combination of red and blue LEDs is favoured over white light illumination for generation of biomass. In addition, we report an exciting finding of exposure to LEDs of red wavelength post-biomass generation lead to enhanced lipid production. This simple process doubled the lipid content harvested in 20days culture period.