Single-step Removal Research Articles

Single-step removal of calcium, fluoride, and phenol from contaminated water by Aquabacterium sp. CZ3 via facultative anaerobic microbially induced calcium precipitation: Kinetics, mechanism, and characterization

Confronting the complex contaminated water, Aquabacterium sp. CZ3 could perform microbially induced calcium precipitation (MICP) under facultative anaerobic condition using phenol as supplementary carbon source. Strain CZ3 exhibited a remarkable ability to remove nitrate, fluoride, calcium and phenol with removal rates of 100.00, 87.50, 66.24 and 100.00%, respectively. The Modified Gompertz model was used for kinetic analysis to determine the optimum conditions for denitrification and degradation of phenol. The mechanism of anaerobic MICP was enhanced by measuring the self-aggregation properties of the isolates. The mechanism of fluoride removal was identified as co-precipitation and adsorption by characterization analysis of the bioprecipitation. Furthermore, the changes in soluble metabolites under phenol stress explained the utilization of phenol as a co-substrate by microorganisms. This is a novel report on phenol degradation by anaerobic MICP, which provides a theoretical basis for expanding its practical application.

Single-step removal of arsenite ions from water through oxidation-coupled adsorption using Mn/Mg/Fe layered double hydroxide as catalyst and adsorbent

This study developed a layered double hydroxides (Mn/Mg/Fe-LDH) material through a simple co-precipitation method. The Mn/Mg/Fe-LDH oxidized arsenite [As(III)] ions into arsenate [As(V)] anions. The As(III) and oxidized As(V) were then adsorbed onto Mn/Mg/Fe-LDH. The adsorption process of arseniate [As(V)] oxyanions by Mn/Mg/Fe-LDH was simultaneously conducted for comparison. Characterization results indicated that (i) the best Mg/Mn/Fe molar ratio was 1/1/1, (ii) Mn/Mg/Fe-LDH structure was similar to that of hydrotalcite, (iii) Mn/Mg/Fe-LDH possessed a positively charged surface (pHIEP of 10.15) and low Brunauer–Emmett–Teller surface area (SBET = 75.2 m2/g), and (iv) Fe2+/Fe3+ and Mn2+/Mn3+/Mn4+ coexisted in Mn/Mg/Fe-LDH. The As(III) adsorption process by Mn/Mg/Fe-LDH was similar to that of As(V) under different experimental conditions (initial solutions pH, coexisting foreign anions, contact times, initial As concentrations, temperatures, and desorbing agents). The Langmuir maximum adsorption capacity of Mn/Mg/Fe-LDH to As(III) (56.1 mg/g) was higher than that of As(V) (32.2 mg/g) at pH 7.0 and 25 °C. X-ray photoelectron spectroscopy was applied to identify the oxidation states of As in laden Mn/Mg/Fe-LDH. The key removal mechanism of As(III) by Mn/Mg/Fe-LDH was oxidation-coupled adsorption, and that of As(V) was reduction-coupled adsorption. The As(V) mechanism adsorption mainly involved: (1) the inner-sphere and outer-sphere complexation with OH groups of Mn/Mg/Fe-LDH and (2) anion exchange with host anions (NO3−) in its interlayer. The primary mechanism adsorption of As(III) was the inner-sphere complexation. The redox reactions made Mn/Mg/Fe-LDH lose its original layer structure after adsorbing As(V) or As(III). The adsorption process was highly irreversible. Mn/Mg/Fe-LDH can decontaminate As from real groundwater samples from 45–92 ppb to 0.35–7.9 ppb (using 1.0 g/L). Therefore, Mn/Mg/Fe-LDH has great potential as a material for removing As.

Three-year outcomes of mixed astigmatism correction with single-step transepithelial photorefractive keratectomy with a large ablation zone.

To evaluate refractive and visual outcomes of single-step transepithelial photorefractive keratectomy (transPRK) in the treatment of mixed astigmatism with the use of an aberration-neutral profile and large ablation zone. Nicolaus Copernicus University and Oftalmika Eye Hospital, Bydgoszcz, Poland. Retrospective, observational case series. This study included patients who underwent transPRK to correct mixed astigmatism and completed the 3-year follow-up. Procedures were performed with an Amaris 750S excimer laser using an aberration-neutral profile and optical zone of 7.2 mm or more. A total 48 eyes of 39 patients were included. Preoperatively, mean spherical manifest refraction was +1.37 ± 0.98 diopter (D) (0.25 to 4.00 D), and astigmatism was -4.00 ± 0.76 D (-2.25 to -6.00 D). Three years postsurgery, it was -0.17 ± 0.26 D and -0.41 ± 0.44 D, respectively. Attempted spherical equivalent correction within ±0.50 D was achieved in 45 eyes (94%) and cylindrical correction in 34 (71%). Preoperative corrected distance visual acuity (CDVA) was 20/20 or better in 38 eyes (79%), and postoperative uncorrected was 20/20 or better in 29 eyes (60.0%). No eye had lost 2 or more Snellen lines of CDVA, whereas 3 eyes (6%) gained 2 or more lines. In 4 eyes (8%), haze of low intensity was observed at the periphery, with scores between 0.5 and 1.0, and only 1 eye getting a score of 2 in 0- to 4-degree scale. Mixed astigmatism correction with large-ablation-zone transPRK provided good results for efficacy, safety, predictability, and visual outcomes in a 3-year follow-up.

Algal process for single-step removal of organic carbon and nutrients: Modeling and optimization of fed-batch operation

A process model to predict the performance of an emergent mixotrophic algal wastewater treatment system was developed and validated. Primary goal of this effort was to predict algal biomass production and the fed-batch cycle time, t*, required to meet the discharge standards under varying influent concentrations of organics and nutrients. Field data from the algal system fed with primary effluent at feed-to-culture volume ratio (Vf:Vc) of 400:300 were used to calibrate the model; additional data from runs with Vf:Vc = 400:300 and with Vf:Vc = 500:200 were used to validate the model. Predicted biomass production agreed well with the measured values in both cases, with r2 = 0.96–0.99, n = 40. Predicted t* also agreed well with the observed values in both cases, with r2 = 0.93–0.94, n = 30. Reasonable agreement was found between the predicted and measured day-to-day concentrations of biochemical oxygen demand (r2 = 0.97; n = 40), ammoniacal-nitrogen (r2 = 0.90; n = 120), and phosphate-phosphorus (r2 = 0.95; n = 120) with Vf:Vc = 400:300. Somewhat lower quality of predictions noted in the runs with Vf:Vc = 500:200 is attributed to the disproportional substrate removals resulting from the mismatch of stoichiometric C:N:P ratio between the algal species and the feed. Sensitivity analysis indicated the kinetic coefficient for phosphate-phosphorus reduction as the most sensitive parameter. Quality of the predictions in this study is comparable to that reported in the literature, but with fewer model parameters.

Abstract 2192: Non-viral genome engineering method allows highly efficient, single-step removal and precise insertion of multiple large genes

Abstract Recent advances in gene editing have enabled the targeted engineering of primary cells to insert entire transgenes without the use of viral vectors. Using these methods, novel genes can be inserted in a seamless manner into the specified genomic locus, realizing the goal of precise targeted genomic modifications. Non-viral modification of primary cells holds potential to significantly reduce costs and time needed for the generation of therapeutic cell products. It has also allowed the generation of personalized cell therapies involving patient-specific manufacturing of DNA constructs, such as for the developed of patient-derived, neoepitope-specific TCR-T cells. Proof-of-concept experiments have shown that non-viral genome engineering methods can integrate small genetic elements such as GFP, while the delivery of larger therapeutically relevant payloads at high efficiency has previously been challenging. Here we describe a proprietary single-step, DNA-mediated method developed for seamlessly engineering fully natural neoepitope-specific TCRs (neoTCR) into the endogenous TCR locus of primary human T cells at high efficiencies (i.e. >50% gene editing efficiency). This method allows the delivery of the two genes comprising the neoTCR without the need for selection necessitated by less efficient approaches. To further evaluate this approach, fresh human donor T cells were engineered to express the patient-specific neoTCR plus two additional gene products, CD8α and CD8β (i.e. precise genome engineering of four ectopic genes). The data shows that these modifications were made at high efficiency, resulting in fully functional CD8 and CD4 T cells. Surface expression of CD8 coreceptor together with the neoE-targeted TCR increased T cell signaling sensitivity of the engineered neoTCR-T cells by 10-100 fold. The potential for off-target cleavage or unexpected genomic outcomes was assessed using multiple methods, including a newly developed primary T cell GUIDE-seq assay. Despite multi-locus editing, no evidence of off-target insertion or unexpected genomic rearrangements were observed. In summary, these results demonstrate the applicability of a single step, highly efficient method for manufacturing fresh human T cells into neoTCR-T cell therapies, engineered with multiple functionalities. This proprietary precision genome engineering technology supports the on-going Phase 1 clinical trial of personalized autologous, NeoTCR-P1 engineered T cell therapies for patients with solid tumors (NCT03970382). Citation Format: Kyle Jacoby, William Lu, Diana Nguyen, Barbara Sennino, Andrew Conroy, Bhamini Purandare, Alex Franzusoff, Stefanie Mandl. Non-viral genome engineering method allows highly efficient, single-step removal and precise insertion of multiple large genes [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2192.

Single-step removal of Hexavalent chromium and phenol using meso zerovalent iron

Novel meso-zero valent iron (mZVI) was investigated for treating complex wastewater containing toxic heavy metal Cr6+ and organic compound phenol. This study is first of its kind illustrating coupled removal in single-step with H2O2 playing a major role as an oxidant and reductant. The mechanism involved was electron transfer from Fe0/2+ to Cr6+ resulting in Fe2+/3+ which in turn was consumed for phenol oxidation returning as Fe2+ into the system for further Cr6+ reduction. While comparing, single-step simultaneous removal of Cr6+ and phenol showed better performance in terms of pollutant removal, Fe2+/3+ recurrent reaction and precipitation generation, double-tep sequential removal performed better in iron active-corrosion time. It was also observed that the entire redox cycle of Cr6+-Cr3+-Cr6+ was reusable for co-contaminant phenol degradation at all pH with the recurrence of Fe2+-Fe3+-Fe2+. The proposed technique was checked for its viability in a single batch reactor and the complex chemistry of the reactions are unfolded by conducting chemical speciation and mass balance study at every stage of reaction. The unique functioning of mZVI was proven with micro-analysis of ZVI's surface and compared with granular ZVI, cZVI. The results obtained from this study open the door for a safer and cleaner single treatment system in removing both toxic heavy metals and organic compounds from contaminated surface water, groundwater and many such industrial effluents.

Anionic structural effect in liquid–liquid separation of phenol from model oil by choline carboxylate ionic liquids

Phenolic compounds exist in crude oil as pollutants, and their removal is vital important for the refining and further application of oils. In traditional separation approaches, strong acid and strong base have to be used to remove these compounds, which may cause serious environmental problems. In this work, 19 kinds of cholinium ionic liquids have been developed to separate phenol from model oil by liquid–liquid extraction. Structural effect of anions of the ionic liquids in the separation is systematically investigated. It is found that depending on the chemical structure of ionic liquids, phenol can be removed from toluene with single-step removal efficiency from 86 to 99% under optimal conditions. The type of substituent groups and the -CH2 number between two carboxylates have obvious effect on the removal efficiency, and more hydrophilic ionic liquids have a stronger extraction performance for phenol. Furthermore, thermodynamic, 13C NMR, 1H NMR and density functional theory calculations have been performed to characterize the extraction process and to understand the extraction mechanism. It is shown that the extraction of phenol from oil to ionic liquid is a favorable process, and this process is mainly driven by enthalpy change. The formation of the hydrogen bond between anion of the ionic liquid and -OH of phenol is the main driving force for the extraction of phenol from oil to the ionic liquids.

Author Correction: Actinia-like multifunctional nanocoagulant for single-step removal of water contaminants.

In the version of the Supplementary Information file originally published with this Article, the images used for Supplementary Fig. 4 were incorrect and have now been replaced. This does not affect the results of the Article.

Actinia-like multifunctional nanocoagulant for single-step removal of water contaminants.

Current technologies for water purification are limited by their contaminant-specific removal capability, requiring multiple processes to meet water quality objectives. Here we show an innovative biomimetic micellar nanocoagulant that imitates the structure of Actinia, a marine predator that uses its tentacles to ensnare food, for the removal of an array of water contaminants with a single treatment step. The Actinia-like micellar nanocoagulant has a core-shell structure and readily disperses in water while maintaining a high stability against aggregation. To achieve effective coagulation, the nanocoagulant everts its configuration, similar to Actinia. The shell hydrolyses into 'flocs' and destabilizes and enmeshes colloidal particles while the core is exposed to water, like the extended tentacles of Actinia, and adsorbs the dissolved contaminants. The technology, with its ability to remove a broad spectrum of contaminants and produce high-quality water, has the potential to be a cost-effective replacement for current water treatment processes.

Sustainable Autarky of Food-Energy-Water (SAFE-Water)

With nearly 70% of the world population already concentrated in towns and cities, and with continuing trends in population growth and sprawl of metropolitan areas, provision of the basic human needs of food, energy, and water to the inhabitants is seen as a major challenge. Being net consumers of food, energy, and water, current urban infrastructure that continues to rely on obsolete technologies to provide these basic needs is not sustainable. Development of modern infrastructure that can recover and recycle energy and materials within the food-energy-water (FEW) sectors of urban sprawl is now recognized as one of the best options to improve the sustainability of both urban and agricultural systems. In this paper, we report on algal-based, photosynthetically oxygenated waste-to-energy recovery (POWER®) system for recovering energy, water, and nutrients from urban wastewaters (UWW) that can be utilized in the food production sector. The POWER® system affords waste treatment, net energy production, and recovery of irrigation-quality water and high-purity crop fertilizers. The strain used in the POWER® system is Galdieria sulphuraria, capable of mixotrophic growth under elevated temperatures of 45 - 55oC and low pH of 2 - 4. The POWER® system provides single-step removal of carbon and nutrients (nitrogen, N and phosphates, P) from UWWs through mixotrophic metabolism. The mixotrophic algal system is capable of incorporating all the C, N, and P in UWW into biomass without any energy input and without any loss of C as CO2 as is the case in the current activated sludge systems. In addition, solar energy captured via photosynthesis is also incorporated into the biomass. The energy-rich biomass is then hydrothermally processed in the POWER® system to yield biocrude and biochar with solubilized N and P in concentrated form as byproducts for recovery and use as fertilizers. This paper includes details of development of the POWER® system and results from a pilot scale study conducted under field conditions at an urban wastewater treatment plant.

Efficient separation of phenolic compounds from model oil by the formation of choline derivative-based deep eutectic solvents

Abstract Phenolic compounds are an important class of compounds for organic chemical industry. In their traditional production processes, strong acid and base have to be used for the separation of phenolic compounds from oils, which often causes serious environmental problems. In this work, choline derivative salts [N 1,1, n C 2 OH]Cl ( n = 1, 4, 6, 8) have been used as new extractants for the separation of 26 kinds of phenolic compounds from model oil (toluene) by forming deep eutectic solvents (DESs). It is found that only 16 kinds of phenolic compounds can be removed from toluene with single-step removal efficiency from 28.1% to 94.7%, strongly depending on the chemical structure of phenolic compounds. The nature, position and number of substituent groups in the phenolic compounds have a great effect on their removal efficiency. Far infrared spectroscopy and density functional theory calculations indicate that hydrogen bonds formed between –OH of the phenolic compounds and anion of the choline derivative salts is the main driving force for such DES-based separation. The correlation observed experimentally between structure of phenolic compounds and their removal efficiencies has been discussed from hydrogen bonding in DESs, electrostatic interaction of cation and anion of the choline salts, and solvation of the phenolic compounds and choline salts in the oil.

Optimizing energy yields from nutrient recycling using sequential hydrothermal liquefaction with Galdieria sulphuraria

Hydrothermal liquefaction (HTL) provides a promising option for extracting bio-crude oil from wet algal biomass. One of the byproducts of HTL is an aqueous phase (AP) rich in organic carbon and nutrients. This study evaluated the hypothesis that recycling the AP to the cultivation step could enhance biomass productivity and net energy yield. Since the yields of bio-crude and nutrients post-HTL are functions of HTL reaction temperature, this study evaluated the impact of reaction temperature on net energy yield. Nutrient recycle experiments were conducted with a low-lipid, acidophilic strain, Galdieria sulphuraria, being developed for single-step removal of organic carbon, nitrogen and phosphorus from urban wastewater. G. sulphuraria was cultivated in different dilutions of the AP generated by HTL performed between 180 and 300°C. Biomass productivity recorded in this study with recycled AP was greater than that in the control by a factor as much as 1.94. Estimates of net energy yields indicate the optimum temperature for the second-stage HTL bio-crude oil extraction from G. sulphuraria to be 280 to 300°C.

Effects of freezing profile parameters on the survival of cryopreserved rat embryonic neural cells

The ability to successfully cryopreserve neural cells would represent an important advance with benefits to neural tissue engineering, neural transplantation, and neuroscience research. We have examined key factors responsible for damage to rat embryonic neural cells during cryopreservation using a two-step temperature profile, with an emphasis on the effects of cooling rate and plunge temperature. Our results indicate that the initial addition of 8% dimethyl sulfoxide (DMSO) and seeding of extracellular ice do not significantly decrease viable cell yield. However, subsequent freezing resulted in significant cell losses for all profile parameter combinations examined. A maximum post-thaw survival of 56% (compared to unfrozen controls) was observed after cooling at 2°C/min to −80°C followed by direct immersion in liquid nitrogen. Single-step removal of DMSO after thawing was associated with an additional 40–70% loss of viable cells, and the number of viable cells was further reduced by approximately 70% after 2 days of cell culture (resulting in a net viable cell yield of 9.6±0.4%). Nonetheless, the cryopreserved neurons that did survive displayed a normal morphology, including formation of neurites. Trends in neuronal viability conformed with predictions of existing theoretical models of cell freezing, with reduced survival for rapid cooling rates or high plunge temperatures (attributable to intracellular ice formation), and decreasing viability with increasing profile duration (consistent with the known effects of cell dehydration at suboptimal cooling rates). These observations suggest that neural cells are good candidates for further refinement of freezing profile design using a physics-based approach to parameter optimization.

Dimorphic aggregation behavior of a fusion polypeptide incorporating a stable protein domain (EGFP) with an amyloidogenic sequence (retroCspA)

We describe the behavior of a polypeptide consisting of the genetic fusion of a structurally stable single-domain protein, EGFP (an analog of the green fluorescent protein) with an amyloidogenic sequence, retroCspA (known to readily form amyloid fibrils). Refolding of the fusion protein through single-step removal of denaturant and salt results in precipitation into amyloid aggregates displaying fibrillar morphology, thioflavin T binding as well as green fluorescence. Refolding through step-wise reduction of denaturant concentration in the presence of salt yields a soluble aggregate containing a folded, thermally-stable, non-fluorescent EGFP domain. Together, these results indicate that retroCspA forces the fusion protein to aggregate; however, the EGFP domain remains folded in a native-like structural format in both soluble aggregates and precipitates.

Step-wise dilution for removal of glycerol from fresh and cryopreserved equine spermatozoa

Osmotic stress is an important component of the damage to spermatozoa during cryopreservation. Osmotic injury, due to hyperosmolar freezing extenders, changes in relative solute concentration in the extra cellular medium during freezing and differences in the relative permeabilities of penetrating cryoprotectants, such as glycerol, and water occur when cryopreserved spermatozoa are diluted into isosmotic media or when spermatozoa are placed in the female reproductive tract. The purpose of the study reported here was to evaluate the effect of step-wise dilution for the removal of the permeating cryoprotectant, glycerol, from both fresh and cryopreserved equine spermatozoa on their motility and viability. There were significant ( P<0.05) effects of osmolality and dilution method on both total and progressive motility as well as viability in fresh spermatozoa. With the rapid, one-step dilution being significantly more detrimental to viability and motility, compared to the fixed molarity and fixed volume-dilutions. With frozen–thawed spermatozoa there were significant effects of stallion on total and progressive motility of spermatozoa after cryopreservation and thawing; however, treatment (type of dilution after thawing) did not affect post-thaw motility. These data indicate that rapid, single-step removal of glycerol from fresh equine spermatozoa results in a post-hyperosmotic stress that is characterized by a reduction in both motility and membrane integrity. This post-hyperosmotic stress can be reduced by a step-wise dilution for removal of glycerol, which improved the maintenance of both motility and membrane integrity. However a similar benefit for step-wise dilution for removal of glycerol was not observed in cryopreserved equine spermatozoa.

Selective oxidation of carbon monoxide in excess hydrogen over Pt-, Ru- and Pd-supported catalysts

Selective oxidation of CO in excess hydrogen has been studied over Pt-, Ru- and Pd-supported on Sibunit (porous carbonaceous material) catalysts. The Ru and Pt catalysts were found to be the most active and selective among the studied catalysts. They provided single-step removal of CO from hydrogen-rich stream both in the absence and presence of CO 2 and H 2O to a PEMFC tolerant level.

Optimising the recovery of recombinant thermostable proteins expressed in mesophilic hosts

The purification of a thermostable Caldocellum saccharolyticum β-glucosidase expressed in Escherichia coli was investigated using heat precipitation of unclarified cell homogenates. Heat treatment at 70 °C was capable of purification with respect to cell debris, small particulates and the majority of cell protein, although E. coli proteins were even more efficiently removed at 80 °C and above. For thermostable proteins expressed in E. coli, a precipitation temperature of 80 °C or greater is recommended for optimal removal of contaminant proteins. In small-scale heating trials, heating rate was found to influence enzyme yield significantly. Losses were minimised when ‘flash-heating’ was employed. The successful single-step removal of particulates, labile protein and nucleic acids was achieved by simultaneous heat-treatment and polyethyleneimine addition, although the purification achieved was additive rather than synergistic.

ChemInform Abstract: Single‐Step Removal of the Allyl Ether Protecting Group with (Ph3P)4RhH and Trifluoroacetic Acid.

ChemInformVolume 21, Issue 43 Natural Products ChemInform Abstract: Single-Step Removal of the Allyl Ether Protecting Group with (Ph3P)4RhH and Trifluoroacetic Acid. F. E. ZIEGLER, F. E. ZIEGLER Sterling Chem. Lab., Yale Univ., New Haven, CT 06511, USASearch for more papers by this authorE. G. BROWN, E. G. BROWN Sterling Chem. Lab., Yale Univ., New Haven, CT 06511, USASearch for more papers by this authorS. B. SOBOLOV, S. B. SOBOLOV Sterling Chem. Lab., Yale Univ., New Haven, CT 06511, USASearch for more papers by this author F. E. ZIEGLER, F. E. ZIEGLER Sterling Chem. Lab., Yale Univ., New Haven, CT 06511, USASearch for more papers by this authorE. G. BROWN, E. G. BROWN Sterling Chem. Lab., Yale Univ., New Haven, CT 06511, USASearch for more papers by this authorS. B. SOBOLOV, S. B. SOBOLOV Sterling Chem. Lab., Yale Univ., New Haven, CT 06511, USASearch for more papers by this author First published: October 23, 1990 https://doi.org/10.1002/chin.199043259Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume21, Issue43October 23, 1990 RelatedInformation

Single-step removal of the allyl ether protecting group with hydridotetrakis(triphenylphosphine)rhodium [(Ph3P)4RhH] and trifluoroacetic acid

Protection de la fonction alcool du cholesterol par un groupement allyl puis deprotection en utilisant (Ph 3 P) 4 RhH/TFA comme catalyseur

Dependence of Epithelial Morphogenesis on Extracellular Acid Mucopolysaccharide (MPS)

The control of morphogenesis is poorly understood, but may involve extracellular substances associated with cell surfaces (e.g. collagen, MPS). Epitheliomesenchymal interactions provide a system for investigating the role of extracellular materials in organogenesis. Since epithelial morphogenesis is not exclusively dependent upon collagen [BERNFIELD, Dev. Biol., in press, 1970], the localization and morphogenetic significance of MPS was studied. The embryonic salivary epithelial-mesenchymal interface contains MPS as shown by (1) specific staining (Alcian blue at various Mg++ concentrations and Schiff reactivity after two-step periodate oxidation), (2) autoradiography (3H-glucosamine and 35SO4) and (3) removal of stain and radioactivity with MPSase. The MPS is localized almost exclusively at the surface of the growing and branching adenomeres. The role of MPS in epithelial morphogenesis was studied by autoradiography and organ culture after treating the rudiments with various enzymes (collagenases, proteases, sialidases and MPSases) to remove mesenchyme and MPS. Untreated rudiments undergo progressive branching and characteristic epithelial morphogenesis in organ culture. Single-step removal of mesenchyme and surface-associated MPS, followed by recombination with fresh mesenchyme, results in loss of adenomeres and a delay i epithelial morphogenesis. Removal of mesenchyme, but not surfact-associated MPS, yields epithelia which maintain a characteristic contour and undergo continued morphogenesis when recombined with fresh mesenchyme. Removal of MPS from these epithelia causes a loss of contour and a delay in morphogenesis. The data indicate that epithelial surface-associated MPS (or MPs-protein complexes) are required for normal epithelial morphogenesis, and that this system may serve as a model for studies of morphogenetically active materials.