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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Physiological and proteomic analyses of Fe(III)-reducing co-cultures of Desulfotomaculum reducens MI-1 and Geobacter sulfurreducens PCA

We established Fe(III)-reducing co-cultures of two species of metal-reducing bacteria, the Gram-positive Desulfotomaculum reducens MI-1 and the Gram-negative Geobacter sulfurreducens PCA. Co-cultures were given pyruvate, a substrate that D. reducens can ferment and use as electron donor for Fe(III) reduction. G. sulfurreducens, which does not utilize pyruvate, relied upon products of pyruvate oxidation by D. reducens (acetate, H2) for use as electron donor in the co-culture. Fe(III) was reduced more quickly in co-cultures relative to pure cultures, and powder X-ray diffraction evidence suggests that both organisms contribute to Fe(III) reduction. Global comparative proteomic analysis was performed in order to observe differential protein abundance during co-culture versus pure culture growth. Proteins previously associated with Fe(III) reduction in G. sulfurreducens, namely c-type cytochromes and type IV pili proteins, were significantly increased in abundance in co-cultures relative to pure cultures. Dreducens ribosomal proteins were significantly increased in co-cultures, likely a reflection of faster growth rates observed for D. reducens cells while in co-culture. Furthermore, we developed multiple reaction monitoring (MRM) assays to quantitate specific biomarker peptides. The assays were validated in pure and co-cultures, and protein abundance ratios from targeted MRM and global proteomic analysis correlate strongly.

Otwell, Annie E.↗
DOE OSTI2019

Application of deoxygenation-aeration cycling to control the predatory bacterium Vampirovibrio chlorellavorus in Chlorella sorokiniana cultures

A previously untested approach was evaluated to enable management of the predatory bacterium, Vampirovibrio chlorellavorus, a pathogen of Chlorella sorokiniana, in suspension cultures grown in a laboratory test reactor. Because V. chlorellavorus is an obligate aerobic bacterium, whereas C. sorokiniana grows under aerobic and anaerobic conditions, deoxygenation of the culture was expected to be detrimental to the pathogen, but not to the algal host. The effect of deoxygenation on the uninfected (healthy) C. sorokiniana suspension cells, compared to the C. sorokiniana-V. chlorellavorus co-culture, was studied in relation to biomass, dissolved oxygen, ratio of C. sorokiniana to V. chlorellavorus DNA, and visual and light microscopic observations. Preliminary experiments were conducted to test the effects of different deoxygenation-aeration cycling regimes on performance of V. chlorellavorus-free C. sorokiniana cultures. To an aerobic culture, pure nitrogen gas was introduced to create anoxic conditions, followed by the injection of ambient air to re-establish an aerobic environment. Under this repeated cycling regime, C. sorokiniana was shown to tolerate the anoxic conditions for extended timespans that ranged from 2 to 8 h over a 5-day test period. The analogous aerobic-anoxic cycling with the C. sorokiniana-V. chlorellavorus co-cultures resulted in ‘near-normal’ growth cycle and harvestable biomass, whereas the continuously-aerated (aerobic) co-cultures that were grown without the deoxygenation step in the cycle collapsed in 3 days. Visual and light microscopic observations revealed intact C. sorokiniana cells were present in the deoxygenated cultures, compared to the aerobically-grown, brown-colored algal cultures consisting of collapsed cells. Quantitative polymerase chain reaction analysis showed continuous increases in the ratio of V. chlorellavorus (16S rDNA) to C. sorokiniana (18S rDNA) DNA in the aerated co-cultures, with greater increases during dark periods, while the pathogen-to-host DNA ratio in the deoxygenated co-cultures was relatively low and algal cells did not collapse, as would be expected following pathogen attack.

Algae, Anoxic, Bomass, Infection, Nitrogen, Quanti↗
DOE OSTI2021

Non-destructive quantification of anaerobic gut fungi and methanogens in co-culture reveals increased fungal growth rate and changes in metabolic flux relative to mono-culture

Abstract Background Quantification of individual species in microbial co-cultures and consortia is critical to understanding and designing communities with prescribed functions. However, it is difficult to physically separate species or measure species-specific attributes in most multi-species systems. Anaerobic gut fungi (AGF) (Neocallimastigomycetes) are native to the rumen of large herbivores, where they exist as minority members among a wealth of prokaryotes. AGF have significant biotechnological potential owing to their diverse repertoire of potent lignocellulose-degrading carbohydrate-active enzymes (CAZymes), which indirectly bolsters activity of other rumen microbes through metabolic exchange. While decades of literature suggest that polysaccharide degradation and AGF growth are accelerated in co-culture with prokaryotes, particularly methanogens, methods have not been available to measure concentrations of individual species in co-culture. New methods to disentangle the contributions of AGF and rumen prokaryotes are sorely needed to calculate AGF growth rates and metabolic fluxes to prove this hypothesis and understand its causality for predictable co-culture design. Results We present a simple, microplate-based method to measure AGF and methanogen concentrations in co-culture based on fluorescence and absorbance spectroscopies. Using samples of < 2% of the co-culture volume, we demonstrate significant increases in AGF growth rate and xylan and glucose degradation rates in co-culture with methanogens relative to mono-culture. Further, we calculate significant differences in AGF metabolic fluxes in co-culture relative to mono-culture, namely increased flux through the energy-generating hydrogenosome organelle. While calculated fluxes highlight uncertainties in AGF primary metabolism that preclude definitive explanations for this shift, our method will enable steady-state fluxomic experiments to probe AGF metabolism in greater detail. Conclusions The method we present to measure AGF and methanogen concentrations enables direct growth measurements and calculation of metabolic fluxes in co-culture. These metrics are critical to develop a quantitative understanding of interwoven rumen metabolism, as well as the impact of co-culture on polysaccharide degradation and metabolite production. The framework presented here can inspire new methods to probe systems beyond AGF and methanogens. Simple modifications to the method will likely extend its utility to co-cultures with more than two organisms or those grown on solid substrates to facilitate the design and deployment of microbial communities for bioproduction and beyond.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

DISCOVR strain pipeline screening – Part II: Winter and summer season areal productivities and biomass compositional shifts in climate-simulation photobioreactor cultures

Assessing the seasonal biomass productivity and compositional shift dynamics under simulated outdoor culture conditions of the top 22 algae strains selected during Tier I flask screening is an important step in the further prioritization of strains with regard to outdoor pond cultivation. These top 22 strains were subjected to Tier II testing in the PNNL Laboratory Environmental Algae Pond Simulator (LEAPS) photobioreactors, simulating light and temperature conditions of 20 cm deep outdoor ponds during the Arizona winter and summer season. All strains were grown in two consecutive nutrient-replete batch culture experiments at their particular optimal medium salinity to quantify their respective seasonal linear-phase areal biomass productivities. To determine biomass compositional shifts in response to nutrient-depletion, the LEAPS cultures were allowed to enter a 9-day nutrient depletion phase at the end of the second batch run. The following strains were evaluated in winter-season climate-simulated cultures and are listed in the order from highest (7.9 g m -2 day -1 ) to lowest (2.3 g m -2 day -1 ) areal N-replete biomass productivity: Monoraphidium minutum 26B-AM, Tetraselmis striata LANL1001, Chlorella vulgaris LRB AZ-1201, Micractinium reisseri NREL14-F2, Monoraphidium sp. MONOR1, Chlorella vulgaris NREL4-C12, Scenedesmus obliquus UTEX393, Scenedesmus acutus LRB-AP-0401, Nannochloropsis oceanica CCAP849/10, and Stichococcus minutus CCALA727. The following strains were evaluated in summer-season climate-simulated cultures and are listed in the order from highest (31.8 g m -2 day -1 ) to lowest (14.2 g m -2 day -1 ) areal N-replete biomass productivity: Picochlorum renovo NREL39-A8, Scenedesmus obliquus UTEX393, Porphyridium cruentum CCMP675, Picochlorum celeri TG2-WT-CSM/EMRE, Chlorella sorokiniana DOE1116, Stichococcus minor CCMP819, Picochlorum oklahomensis CCMP2329, Chlorella sorokiniana DOE1412 (UTEXB3016), Scenedesmus rubescens NREL46B-D3, Picochlorum soloecismus DOE101, Tetraselmis striata LANL1001, Scenedesmus obliquus DOE 0152.z, and Agmenellum quadruplicatum UTEX2268. All LEAPS cultures experienced a significant reduction in areal biomass productivity in response to nutrient-depletion, from 7-16% in the winter season simulation and up to 1-60% in the summer season simulation. Finally, for 10 of the strains tested, the carbohydrate content more than doubled upon nutrient depletion, and for 9 strains, the lipid content increased by over 50% of the initial content.

09 BIOMASS FUELS↗
NASA NTRS2000

Differentiation of mammalian skeletal muscle cells cultured on microcarrier beads in a rotating cell culture system

The growth and repair of adult skeletal muscle are due in part to activation of muscle precursor cells, commonly known as satellite cells or myoblasts. These cells are responsive to a variety of environmental cues, including mechanical stimuli. The overall goal of the research is to examine the role of mechanical signalling mechanisms in muscle growth and plasticity through utilisation of cell culture systems where other potential signalling pathways (i.e. chemical and electrical stimuli) are controlled. To explore the effects of decreased mechanical loading on muscle differentiation, mammalian myoblasts are cultured in a bioreactor (rotating cell culture system), a model that has been utilised to simulate microgravity. C2C12 murine myoblasts are cultured on microcarrier beads in a bioreactor and followed throughout differentiation as they form a network of multinucleated myotubes. In comparison with three-dimensional control cultures that consist of myoblasts cultured on microcarrier beads in teflon bags, myoblasts cultured in the bioreactor exhibit an attenuation in differentiation. This is demonstrated by reduced immunohistochemical staining for myogenin and alpha-actinin. Western analysis shows a decrease, in bioreactor cultures compared with control cultures, in levels of the contractile proteins myosin (47% decrease, p < 0.01) and tropomyosin (63% decrease, p < 0.01). Hydrodynamic measurements indicate that the decrease in differentiation may be due, at least in part, to fluid stresses acting on the myotubes. In addition, constraints on aggregate size imposed by the action of fluid forces in the bioreactor affect differentiation. These results may have implications for muscle growth and repair during spaceflight.

Non-NASA Center↗
DOE OSTI2018

Different culture media modulate growth, heterogeneity, and senescence in human mammary epithelial cell cultures

The ability to culture normal human mammary epithelial cells (HMEC) greatly facilitates experiments that seek to understand both normal mammary cell biology and the many differences between normal and abnormal human mammary epithelia. To maximize in vivo relevance, the primary cell culture conditions should maintain cells in states that resemble in vivo as much as possible. Towards this goal, we compared the properties of HMEC strains from two different reduction mammoplasty tissues that were grown in parallel using different media and culture conditions. Epithelial organoids were initiated into three different media: two commonly used serum-free-media, MCDB 170-type (e.g. MEGM) and WIT-P, and a low stress media, M87A. Growth, lineage heterogeneity, p16 protein expression, and population doublings to senescence were measured for each culture condition. MCDB 170 caused rapid senescence and loss of heterogeneity within 2 to 3 passages, but some cultures went through the 1 to 2 month process of selection to generate clonal finite post-selection post-stasis cells. WIT-P caused impressive expansion of luminal cells in 2nd passage followed by their near complete disappearance by passage 4 and senescence shortly thereafter. M87A supported as much as twice the number of population doublings compared to either serum-free medium, and luminal and myoepithelial cells were present for as many as 8 passages. Thus, of the three media compared, WIT-P and MCDB 170 imposed rapid senescence and loss of lineage heterogeneity, phenotypes consistent with cells maintained in high-stress conditions, while M87A supported cultures that maintained multiple lineages and robust growth for up to 60 population doublings. In conjunction with previous studies examining the molecular properties of cultures grown in these media, we conclude that M87A medium is most able to support long-term culture of multiple lineages similar to in vivo conditions, thereby facilitating investigations of normal HMEC biology relevant to the mammary gland in situ.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1998

Use of an adaptable cell culture kit for performing lymphocyte and monocyte cell cultures in microgravity

The results of experiments performed in recent years on board facilities such as the Space Shuttle/Spacelab have demonstrated that many cell systems, ranging from simple bacteria to mammalian cells, are sensitive to the microgravity environment, suggesting gravity affects fundamental cellular processes. However, performing well-controlled experiments aboard spacecraft offers unique challenges to the cell biologist. Although systems such as the European 'Biorack' provide generic experiment facilities including an incubator, on-board 1-g reference centrifuge, and contained area for manipulations, the experimenter must still establish a system for performing cell culture experiments that is compatible with the constraints of spaceflight. Two different cell culture kits developed by the French Space Agency, CNES, were recently used to perform a series of experiments during four flights of the 'Biorack' facility aboard the Space Shuttle. The first unit, Generic Cell Activation Kit 1 (GCAK-1), contains six separate culture units per cassette, each consisting of a culture chamber, activator chamber, filtration system (permitting separation of cells from supernatant in-flight), injection port, and supernatant collection chamber. The second unit (GCAK-2) also contains six separate culture units, including a culture, activator, and fixation chambers. Both hardware units permit relatively complex cell culture manipulations without extensive use of spacecraft resources (crew time, volume, mass, power), or the need for excessive safety measures. Possible operations include stimulation of cultures with activators, separation of cells from supernatant, fixation/lysis, manipulation of radiolabelled reagents, and medium exchange. Investigations performed aboard the Space Shuttle in six different experiments used Jurkat, purified T-cells or U937 cells, the results of which are reported separately. We report here the behaviour of Jurkat and U937 cells in the GCAK hardware in ground-based investigations simulating the conditions expected in the flight experiment. Several parameters including cell concentration, time between cell loading and activation, and storage temperature on cell survival were examined to characterise cell response and optimise the experiments to be flown aboard the Space Shuttle. Results indicate that the objectives of the experiments could be met with delays up to 5 days between cell loading into the hardware and initial in flight experiment activation, without the need for medium exchange. Experiment hardware of this kind, which is adaptable to a wide range of cell types and can be easily interfaced to different spacecraft facilities, offers the possibility for a wide range of experimenters successfully and easily to utilise future flight opportunities.

short duration↗
DOE OSTI2018

Restoration of hair-inductive activity of cultured human follicular keratinocytes by co-culturing with dermal papilla cells

Highlights: • Monocultured human ORS cells lose hair-inductive activity (trichogenicity). • The trichogenicity of human ORS cells can be restored by co-culturing with human DP cells. • Human DP cells regulate expression of a number of genes in co-cultured ORS cells. Hair follicle outer root sheath (ORS) cells can be expanded in vitro, but often lose receptivity to hair-inducing dermal signals. Recent studies have shown hair-inductive activity (trichogenicity) can be restored in rat ORS cells expanded with a fibroblast feeder by co-culturing with rat vibrissae dermal papilla (DP) cells. In this study, we investigated whether the trichogenicity of human ORS cells can be restored by co-culturing with human DP cells. ORS cells from human scalp hair follicles were cultured independently or with DP cells for 5 days and implanted into nude mice alongside freshly isolated neonatal mouse dermal cells. Although there was no hair induction when monocultured ORS cells were implanted, it was observed in co-cultured ORS cells. We also observed differential regulation of a number of genes in ORS cells co-cultured with DP cells compared to monocultured ORS cells as examined by microarray. Taken together, our data strongly suggest that human DP cells restore the trichogenicity of co-cultured ORS cells by influencing ORS gene expression through paracrine factors.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Increasing cell culture population doublings for long-term growth of finite life span human cell cultures

Cell culture media formulations for culturing human epithelial cells are herein described. Also described are methods of increasing population doublings in a cell culture of finite life span human epithelial cells and prolonging the life span of human cell cultures. Using the cell culture media disclosed alone and in combination with addition to the cell culture of a compound associated with anti-stress activity achieves extended growth of pre-stasis cells and increased population doublings and life span in human epithelial cell cultures.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2017

The laboratory environmental algae pond simulator (LEAPS) photobioreactor: Validation using outdoor pond cultures of Chlorella sorokiniana and Nannochloropsis salina

A bench-scale photobioreactor system, the Laboratory Environmental Algae Pond Simulator (LEAPS), was designed and constructed to simulate outdoor pond cultivation for a wide range of geographical locations and seasons. The LEAPS consists of six well-mixed glass column photobioreactors submerged in a temperature controlled waterbath (-2 °C to >60 °C) and illuminated from above by a programmable multicolor LED lighting system (0 to 2,500 µmol/m 2 -sec). Measured incident light intensities and water temperatures deviated from the respective light and temperature setpoints on average only 2.3% and 0.9%, demonstrating accurate simulation of light and temperature conditions measured in outdoor ponds. In order to determine whether microalgae strains cultured in the LEAPS exhibit the same linear phase biomass productivity as in outdoor ponds, Chlorella sorokiniana and Nannochloropsis salina were cultured in the LEAPS bioreactors using light and temperature scripts measured previously in the respective outdoor pond studies. For Chlorella sorokiniana, the summer season biomass productivity in the LEAPS was 6.6% and 11.3% lower than in the respective outdoor ponds in Rimrock, Arizona, and Delhi, California; however, these differences were not statistically significant. For Nannochloropsis salina, the winter season biomass productivity in the LEAPS was 9.2% higher than in the respective outdoor ponds in Tucson, Arizona, a difference shown to be not statistically significant. Potential reasons for the positive or negative divergence in LEAPS performance, relative to outdoor ponds, are discussed. To demonstrate the utility of the LEAPS in predicting productivity, two other strains – Scenedesmus obliquus and Stichococcus minor – were evaluated using the summer season script for Rimrock, Arizona. For both strains, the productivity was around 11.6 g/m 2 -day at 25 cm culture depth. In conclusion, the LEAPS is an accurate pond simulator and thus offers a reliable, fast, and cost-effective way to screen microalgae strains and operating conditions for high biomass productivity and co-product yields.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2024

Species-specific ribosomal RNA-FISH identifies interspecies cellular-material exchange, active-cell population dynamics and cellular localization of translation machinery in clostridial cultures and co-cultures

ABSTRACT The development of synthetic microbial consortia in recent years has revealed that complex interspecies interactions, notably the exchange of cytoplasmic material, exist even among organisms that originate from different ecological niches. Although morphogenetic characteristics, viable RNA and protein dyes, and fluorescent reporter proteins have played an essential role in exploring such interactions, we hypothesized that ribosomal RNA-fluorescence in situ hybridization (rRNA-FISH) could be adapted and applied to further investigate interactions in synthetic or semisynthetic consortia. Despite its maturity, several challenges exist in using rRNA-FISH as a tool to quantify individual species population dynamics and interspecies interactions using high-throughput instrumentation such as flow cytometry. In this work, we resolve such challenges and apply rRNA-FISH to double and triple co-cultures of Clostridium acetobutylicum, Clostridium ljungdahlii, and Clostridium kluyveri . In pursuing our goal to capture each organism’s population dynamics, we demonstrate dynamic rRNA, and thus ribosome, exchange between the three species leading to the formation of hybrid cells. We also characterize the localization patterns of the translation machinery in the three species, identifying distinct, dynamic localization patterns among them. Our data also support the use of rRNA-FISH to assess the culture’s health and expansion potential, and, here again, our data find surprising differences among the three species examined. Taken together, our study argues for rRNA-FISH as a valuable and accessible tool for quantitative exploration of interspecies interactions, especially in organisms which cannot be genetically engineered or in consortia where selective pressures to maintain recombinant species cannot be used. IMPORTANCE Though dyes and fluorescent reporter proteins have played an essential role in identifying microbial species in co-cultures, we hypothesized that ribosomal RNA-fluorescence in situ hybridization (rRNA-FISH) could be adapted and applied to quantitatively probe complex interactions between organisms in synthetic consortia. Despite its maturity, several challenges existed before rRNA-FISH could be used to study Clostridium co-cultures of interest. First, species-specific probes for Clostridium acetobutylicum and Clostridium ljungdahlii had not been developed. Second, “state-of-the-art” labeling protocols were tedious and often resulted in sample loss. Third, it was unclear if FISH was compatible with existing fluorescent reporter proteins. We resolved these key challenges and applied the technique to co-cultures of C. acetobutylicum , C. ljungdahlii , and Clostridium kluyveri . We demonstrate that rRNA-FISH is capable of identifying rRNA/ribosome exchange between the three organisms and characterized rRNA localization patterns in each. In combination with flow cytometry, rRNA-FISH can capture sub-population dynamics in co-cultures.

Hill, John D.↗
DOE OSTI2019

High proportions of bacteria are culturable across major biomes

Abstract The paradigm that only 1% of microbes are culturable has had a profound impact on our understanding of microbial ecology and is still a major motivation for mostly using molecular tools to characterize microbial communities. However, this point is often expressed vaguely, suggesting that some scientists have different interpretations of the paradigm. In addition, there have been substantial advances in cultivation techniques suggesting that this paradigm may no longer be correct. To quantify bacterial culturability across six major biomes, I found that the median 16S rRNA similarity of bacteria to known cultured relatives was 97.3 ± 2.3% (s.d.). Furthermore, 52.0 ± 24% of sequences and 34.9 ± 23% of taxa (defined as >97% similar) had a closely related cultured relative. Thus, many cells and taxa across environments are culturable with known techniques, suggesting that the 1% paradigm is no longer correct.

Martiny, Adam C. (ORCID:0000000328294314)↗
DOE OSTI2016

Polymer microfilters with nanostructured surfaces for the culture of circulating cancer cells

There is a critical need to improve the accuracy of drug screening and testing through the development of in vitro culture systems that more effectively mimic the in vivo environment. Surface topographical features on the nanoscale level, in short nanotopography, effect the cell growth patterns, and hence affect cell function in culture. We report the preliminary results on the fabrication, and subsequent cellular growth, of nanoscale surface topography on polymer microfilters using cell lines as a precursor to circulating tumor cells (CTCs). To create various nanoscale features on the microfilter surface, we used reactive ion etching (RIE) with and without an etching mask. An anodized aluminum oxide (AAO) membrane fabricated directly on the polymer surface served as an etching mask. Polymer filters with a variety of modified surfaces were used to compare the effects on the culture of cancer cell lines in blank culture wells, with untreated microfilters or with RIE-treated microfilters. We then report the differences of cell shape, phenotype and growth patterns of bladder and glioblastoma cancer cell lines after isolation on the various types of material modifications. Our data suggest that RIE modified polymer filters can isolate model cell lines while retaining ell viability, and that the RIE filter modification allows T24 monolayering cells to proliferate as a structured cluster. Copyright 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Makarova, Olga V.↗
DOE OSTI2022

13 C-Isotope-Assisted Assessment of Metabolic Quenching During Sample Collection from Suspension Cell Cultures

Metabolomics and fluxomics are core approaches to directly profile and interrogate cellular metabolism in response to various genetic or environmental perturbations. In order to accurately measure the abundance and isotope enrichment of intracellular metabolites, cell culture samples must be rapidly harvested and cold-quenched to preserve the in vivo metabolic state of the cells at the time of sample collection. When dealing with suspension cultures, this process is complicated by the need to separate the liquid culture media from cellular biomass prior to metabolite extraction. Here, we examine the efficacy of several commonly used metabolic quenching methods, using the model cyanobacterium Synechocystis sp. PCC 6803 as an example. Multiple 13 C-labeled compounds, including 13 C-bicarbonate, 13 C-glucose and 13 C-glutamine, were used as tracers during the sample collection and cold-quenching process to assess the extent of metabolic turnover after cells were harvested from culture flasks. We show that the combination of rapid filtration followed by 100% cold (–80°C) methanol quenching exhibits the highest quenching efficiency, while mixing cell samples with a partially frozen 30% methanol slurry (–24°C) followed by centrifugation is slightly less effective at quenching metabolism but enables less laborious sample processing. By contrast, rapidly mixing the cells with a saline ice slurry (~0°C) is less effective as indicated by high isotope-labeling rates after sample harvest, while mixing the cells with 60% cold methanol (–65°C) prior to centrifugation causes significant metabolite loss. Furthermore, this study demonstrates a rigorous, quantitative, and broadly applicable method for assessing the metabolic quenching efficacy of protocols used for sample collection in metabolomics and fluxomics studies.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2015

The United States Culture Collection Network (USCCN): Enhancing Microbial Genomics Research through Living Microbe Culture Collections

The mission of the United States Culture Collection Network (USCCN; http://usccn.org) is "to facilitate the safe and responsible utilization of microbial resources for research, education, industry, medicine, and agriculture for the betterment of human kind." Microbial culture collections are a key component of life science research, biotechnology, and emerging global biobased economies. Representatives and users of several microbial culture collections from the United States and Europe gathered at the University of California, Davis, to discuss how collections of microorganisms can better serve users and stakeholders and to showcase existing resources available in public culture collections.

Boundy-Mills, K.↗
DOE OSTI2017

Subretinal Pigment Epithelial Deposition of Drusen Components Including Hydroxyapatite in a Primary Cell Culture Model

Extracellular deposits containing hydroxyapatite, lipids, proteins, and trace metals that form between the basal lamina of the RPE and the inner collagenous layer of Bruch’s membrane are hallmarks of early AMD. We examined whether cultured RPE cells could produce extracellular deposits containing all of these molecular components. Retinal pigment epithelium cells isolated from freshly enucleated porcine eyes were cultured on Transwell membranes for up to 6 months. Deposit composition and structure were characterized using light, fluorescence, and electron microscopy; synchrotron x-ray diffraction and x-ray fluorescence; secondary ion mass spectroscopy; and immunohistochemistry. Apparently functional primary RPE cells, when cultured on 10-lm-thick inserts with 0.4-lm-diameter pores, can produce sub-RPE deposits that contain hydroxyapatite, lipids, proteins, and trace elements, without outer segment supplementation, by 12 weeks. In conclusion, the data suggest that sub-RPE deposit formation is initiated, and probably regulated, by the RPE, as well as the loss of permeability of the Bruch’s membrane and choriocapillaris complex associated with age and early AMD. This cell culture model of early AMD lesions provides a novel system for testing new therapeutic interventions against sub-RPE deposit formation, an event occurring well in advance of the onset of vision loss.

59 BASIC BIOLOGICAL SCIENCES↗