CRISPR/Cas mediated genome editing in potato: Past achievements and future directions

Genome engineering has been re-shaping plant biotechnology and agriculture. Crop improvement using the recently developed gene editing techniques is now easier, faster, and more precise than ever. Although considered to be a global food security crop, potato has not benefitted enough from diverse collection of these techniques. Unique genetic features of cultivated potatoes such as tetrasomic inheritance, high genomic heterozygosity, and inbreeding depression hamper conventional breeding of this important crop. Therefore, genome editing provides an excellent arsenal of tools for trait improvement in potato. Moreover, using specific transformation protocols, it is possible to engineer transgene free commercial varieties. In this review we first describe the past achievements in potato genome editing and highlight some of the missing aspects of these efforts. Then, we discuss about technical challenges of genome editing in potato and present approaches to overcome these difficulties. Finally, we talk about genome editing applications that have not been explored in potato and point out some of the missing venues in literature.

Cas9-mediated mutagenesis of potato starch-branching enzymes generates a range of tuber starch phenotypes

We investigated whether Cas9-mediated mutagenesis of starch-branching enzymes (SBEs) in tetraploid potatoes could generate tuber starches with a range of distinct properties. Constructs containing the Cas9 gene and sgRNAs targeting SBE1, SBE2 or both genes were introduced by Agrobacterium-mediated transformation or by PEG-mediated delivery into protoplasts. Outcomes included lines with mutations in all or only some of the homoeoalleles of SBE genes and lines in which homoeoalleles carried several different mutations. DNA delivery into protoplasts resulted in mutants with no detectable Cas9 gene, suggesting the absence of foreign DNA. Selected mutants with starch granule abnormalities had reductions in tuber SBE1 and/or SBE2 protein that were broadly in line with expectations from genotype analysis. Strong reduction in both SBE isoforms created an extreme starch phenotype, as reported previously for low-SBE potato tubers. HPLC-SEC and ¹ H NMR revealed a decrease in short amylopectin chains, an increase in long chains and a large reduction in branching frequency relative to wild-type starch. Mutants with strong reductions in SBE2 protein alone had near-normal amylopectin chain-length distributions and only small reductions in branching frequency. However, starch granule initiation was enormously increased: cells contained many granules of <4 μm and granules with multiple hila. Thus, large reductions in both SBEs reduce amylopectin branching during granule growth, whereas reduction in SBE2 alone primarily affects numbers of starch granule initiations. Our results demonstrate that Cas9-mediated mutagenesis of SBE genes has the potential to generate new, potentially valuable starch properties without integration of foreign DNA into the genome.

Re-programming of gene expression in the CS8 rice line over-expressing ADPglucose pyrophosphorylase induces a suppressor of starch biosynthesis

The CS8 transgenic rice (Oryza sativa L.) lines expressing an up-regulated glgC gene produced higher levels of ADPglucose (ADPglc), the substrate for starch synthases. However, the increase in grain weight was much less than the increase in ADPglc levels suggesting one or more downstream rate-limiting steps. Endosperm starch levels were not further enhanced in double transgenic plants expressing both glgC and the maize brittle-1 gene, the latter responsible for transport of ADPglc into the amyloplast. These studies demonstrate that critical processes within the amyloplast stroma restrict maximum carbon flow into starch. RNA-seq analysis showed extensive re-programming of gene expression in the CS8 with 2073 genes up-regulated and 140 down-regulated. One conspicuous gene, up-regulated ~15-fold, coded for a biochemically uncharacterized starch binding domain-containing protein (SBDCP1) possessing a plastid transit peptide. Confocal microscopy and transmission electron microscopy analysis confirmed that SBDCP1 was located in the amyloplasts. Reciprocal immunoprecipitation and pull-down assays indicated an interaction between SBDCP1 and starch synthase IIIa (SSIIIa), which was down-regulated at the protein level in the CS8 line. Furthermore, binding by SBDCP1 inhibited SSIIIa starch polymerization activity in a non-competitive manner. Surprisingly, artificial microRNA gene suppression of SBDCP1 restored protein expression levels of SSIIIa in the CS8 line resulting in starch with lower amylose content and increased amylopectin chains with a higher degree of polymerization. Collectively, our results support the involvement of additional non-enzymatic factors such as SBDCP in starch biosynthesis.

Mechanism Underlying Heat Stability of the Rice Endosperm Cytosolic ADP-Glucose Pyrophosphorylase

Rice grains accumulate starch as their major storage reserve whose biosynthesis is sensitive to heat. ADP-glucose pyrophosphorylase (AGPase) is among the starch biosynthetic enzymes severely affected by heat stress during seed maturation. To increase the heat tolerance of the rice enzyme, we engineered two dominant AGPase subunits expressed in developing endosperm, the large (L2) and small (S2b) subunits of the cytosol-specific AGPase. Bacterial expression of the rice S2b with the rice L2, potato tuber LS (pLS), or with the mosaic rice-potato large subunits, L2-pLS and pLS-L2, produced heat-sensitive recombinant enzymes, which retained less than 10% of their enzyme activities after 5 min incubation at 55°C. However, assembly of the rice L2 with the potato tuber SS (pSS) showed significantly increased heat stability comparable to the heat-stable potato pLS/pSS. The S2b assembled with the mosaic L2-pLS subunit showed 3-fold higher sensitivity to 3-PGA than L2/S2b, whereas the counterpart mosaic pLS-L2/S2b showed 225-fold lower sensitivity. Introduction of a QTC motif into S2b created an N-terminal disulfide linkage that was cleaved by dithiothreitol reduction. The QTC enzyme showed moderate heat stability but was not as stable as the potato AGPase. While the QTC AGPase exhibited approximately fourfold increase in 3-PGA sensitivity, its substrate affinities were largely unchanged. Random mutagenesis of S2b^QTC produced six mutant lines with elevated production of glycogen in bacteria. All six lines contained a L379F substitution, which conferred enhanced glycogen production in bacteria and increased heat stability. Modeled structure of this mutant enzyme revealed that this highly conserved leucine residue is located in the enzyme's regulatory pocket that provides interaction sites for activators and inhibitors. Our molecular dynamic simulation analysis suggests that introduction of the QTC motif and the L379F mutation improves enzyme heat stability by stabilizing their backbone structures possibly due to the increased number of H-bonds between the small subunits and increased intermolecular interactions between the two SSs and two LSs at elevated temperature.

Analysis of the Rice ADP-Glucose Transporter (OsBT1) Indicates the Presence of Regulatory Processes in the Amyloplast Stroma That Control ADP-Glucose Flux into Starch

Previous studies showed that efforts to further elevate starch synthesis in rice (Oryza sativa) seeds overproducing ADP-glucose (ADPglc) were prevented by processes downstream of ADPglc synthesis. Here, we identified the major ADPglc transporter by studying the shrunken3 locus of the EM1093 rice line, which harbors a mutation in the BRITTLE1 (BT1) adenylate transporter (OsBt1) gene. Despite containing elevated ADPglc levels (approximately 10-fold) compared with the wild-type, EM1093 grains are small and shriveled due to the reduction in the amounts and size of starch granules. Increases in ADPglc levels in EM1093 were due to their poor uptake of ADP-[(14)C]glc by amyloplasts. To assess the potential role of BT1 as a rate-determining step in starch biosynthesis, the maize ZmBt1 gene was overexpressed in the wild-type and the GlgC (CS8) transgenic line expressing a bacterial glgC-TM gene. ADPglc transport assays indicated that transgenic lines expressing ZmBT1 alone or combined with GlgC exhibited higher rates of transport (approximately 2-fold), with the GlgC (CS8) and GlgC/ZmBT1 (CS8/AT5) lines showing elevated ADPglc levels in amyloplasts. These increases, however, did not lead to further enhancement in seed weights even when these plant lines were grown under elevated CO2. Overall, our results indicate that rice lines with enhanced ADPglc synthesis and import into amyloplasts reveal additional barriers within the stroma that restrict maximum carbon flow into starch.

Significant worsening sperm parameters are associated to testicular hypotrophy in patients with a high grade varicocele

OBJECTIVE

To investigate the relationship between testicular volume and semen parameter sin patients with unilateral high grade left varicocele.

MATERIAL AND METHODS

One hundred eighty seven patients who had left high grade varicocele aged 19-to-25 years were included in this study. All patients underwent a standard evaluation, including medical history and physical examination. The percentage testicular volume difference between the right and left testicles was calculated. The patients were divided into the following three groups; Group 1 (n=72) testicular volume difference <10%, testicular volume difference 10%-20% Group 2 (n=74) and testicular volume difference >20% Group 3 (n=41).

RESULTS

The mean age and BMI of the patients were 21.5 years and 23.1kg/m(2), respectively (P=.596, P=.943). The semen parameters and testicular volumes of the three groups were compared. The total motile sperm count, percentage of motile sperm, percentage of normal morphology sperm were found to be lower in Group 3 (P=.011, P=.012, P=.029 respectively). The mean testicular volumes for the left and the right testis were found to be 15.2cm(3) and 17.7cm(3) (P<.001), respectively. No significant difference was found in the right testicular volumes between groups (17.4, 17.7 and 18.1cm(3), P=.573).

CONCLUSIONS

A high grade left testicular varicocele is associated with ipsilateral testicular hypotrophy and parallel to worsened sperm parameters.

Substrate binding properties of potato tuber ADP-glucose pyrophosphorylase as determined by isothermal titration calorimetry

Substrate binding properties of the large (LS) and small (SS) subunits of potato tuber ADP-glucose pyrophosphorylase were investigated by using isothermal titration calorimetry. Our results clearly show that the wild type heterotetramer (S(WT)L(WT)) possesses two distinct types of ATP binding sites, whereas the homotetrameric LS and SS variant forms only exhibited properties of one of the two binding sites. The wild type enzyme also exhibited significantly increased affinity to this substrate compared to the homotetrameric enzyme forms. No stable binding was evident for the second substrate, glucose-1-phosphate, in the presence or absence of ATPγS suggesting that interaction of glucose-1-phosphate is dependent on hydrolysis of ATP and supports the Theorell-Chance bi bi reaction mechanism.

The role of the large subunit in redox regulation of the rice endosperm ADP-glucose pyrophosphorylase

The starch regulatory enzyme ADP-glucose pyrophosphorylase is activated by 3-phosphoglyceric acid (3-PGA) and inhibited by inorganic phosphate (Pi ). The activity of the plastid-localized enzyme is also subject to fine regulation by redox control in response to changing light and sugar levels. The less active oxidized form of the enzyme contains an inter-subunit disulfide bond formed between the pair of small subunit's Cys12 residues of the heterotetrameric enzyme. Although this cysteine residue is not conserved in the small subunits of cereal endosperm cytosolic AGPases, biochemical studies of the major rice endosperm enzyme indicate that the cytosolic isoform, like the plastidial enzymes, is subject to redox control. Kinetic analysis revealed that the reduced forms of the partially purified native and purified recombinant AGPases have 6- and 3.4-fold, respectively, more affinity to 3-PGA, rendering the enzymes more active at lower 3-PGA concentration than the non-reduced enzyme. Truncation of the large subunit by removal of N-terminal peptide resulted in a decrease in 3-PGA affinity and loss of redox response of the enzyme. Site-directed mutagenesis of the conserved cysteine residues at the N-terminal of the large subunit showed that C47 and C58, but not C12, are essential for proper redox response of the enzyme. Overall, our results show that the major rice endosperm AGPase activity is controlled by a combination of allosteric regulation and redox control, the latter through modification of the large subunit instead of the small subunit as evident in the plastid-localized enzyme.

The rice endosperm ADP-glucose pyrophosphorylase large subunit is essential for optimal catalysis and allosteric regulation of the heterotetrameric enzyme

Although an alternative pathway has been suggested, the prevailing view is that starch synthesis in cereal endosperm is controlled by the activity of the cytosolic isoform of ADPglucose pyrophosphorylase (AGPase). In rice, the cytosolic AGPase isoform is encoded by the OsAGPS2b and OsAGPL2 genes, which code for the small (S2b) and large (L2) subunits of the heterotetrameric enzyme, respectively. In this study, we isolated several allelic missense and nonsense OsAGPL2 mutants by N-methyl-N-nitrosourea (MNU) treatment of fertilized egg cells and by TILLING (Targeting Induced Local Lesions in Genomes). Interestingly, seeds from three of the missense mutants (two containing T139I and A171V) were severely shriveled and had seed weight and starch content comparable with the shriveled seeds from OsAGPL2 null mutants. Results from kinetic analysis of the purified recombinant enzymes revealed that the catalytic and allosteric regulatory properties of these mutant enzymes were significantly impaired. The missense heterotetramer enzymes and the S2b homotetramer had lower specific (catalytic) activities and affinities for the activator 3-phosphoglycerate (3-PGA). The missense heterotetramer enzymes showed more sensitivity to inhibition by the inhibitor inorganic phosphate (Pi) than the wild-type AGPase, while the S2b homotetramer was profoundly tolerant to Pi inhibition. Thus, our results provide definitive evidence that starch biosynthesis during rice endosperm development is controlled predominantly by the catalytic activity of the cytoplasmic AGPase and its allosteric regulation by the effectors. Moreover, our results show that the L2 subunit is essential for both catalysis and allosteric regulatory properties of the heterotetramer enzyme.

Improving starch yield in cereals by over-expression of ADPglucose pyrophosphorylase: expectations and unanticipated outcomes

Significant improvements in crop productivity are required to meet the nutritional requirements of a growing world population. This challenge is magnified by an increased demand for bioenergy as a means to mitigate carbon inputs into the environment. Starch is a major component of the harvestable organs of many crop plants, and various endeavors have been taken to improve the yields of starchy organs through the manipulation of starch synthesis. Substantial efforts have centered on the starch regulatory enzyme ADPglucose pyrophosphorylase (AGPase) due to its pivotal role in starch biosynthesis. These efforts include over-expression of this enzyme in cereal plants such as maize, rice and wheat as well as potato and cassava, as they supply the bulk of the staple food worldwide. In this perspective, we describe efforts to increase starch yields in cereal grains by first providing an introduction about the importance of source-sink relationship and the motives behind the efforts to alter starch biosynthesis and turnover in leaves. We then discuss the catalytic and regulatory properties of AGPase and the molecular approaches used to enhance starch synthesis by manipulation of this process during grain filling using seed-specific promoters. Several studies have demonstrated increases in starch content per seed using endosperm-specific promoters, but other studies have demonstrated an increase in seed number with only marginal impact on seed weight. Potential mechanisms that may be responsible for this paradoxical increase in seed number will also be discussed. Finally, we describe current efforts and future prospects to improve starch yield in cereals. These efforts include further enhancement of starch yield in rice by augmenting the process of ADPglucose transport into amyloplast as well as other enzymes involved in photoassimilate partitioning in seeds.

Effect of tempol, a membrane-permeable radical scavenger, on mesenteric blood flow and organ injury in a murine cecal ligation and puncture model of septic shock

BACKGROUND

Interventions that reduce the generation or the effects of reactive oxygen species exert beneficial effects in a variety of models of septic shock. We investigated the effect of tempol, a low-molecular-weight membrane-permeable radical scavenger, on mesenteric blood flow and organ injury in a murine cecal ligation and puncture (CLP) model of septic shock.

MATERIALS AND METHODS

Forty-four Swiss albino mice were anesthetized with chloral hydrate (400 mg/kg, i.p.) and subjected to CLP (except for the sham-operated animals). The animals were divided randomly into 4 groups: the 1st group was sham operated (sham-operated group, n = 10); the 2nd group underwent CLP and was injected with saline (CLP + saline group, n = 12); the 3rd group was sham operated and treated with tempol (10 mg/kg, i.p., sham-treated + tempol group, n = 10); the 4th group underwent CLP and was treated with tempol (10 mg/kg, i.p., CLP + tempol group, n = 12). Mesenteric arterial blood flow (MABF) was measured by Doppler ultrasound. Poly(adenosine 5'-diphosphate-ribose) polymerase (PARP) activity was examined in the liver, lung, and kidneys.

RESULTS

In the CLP + saline group, the MABF was significantly lower than in the sham-operated group (p < 0.001). After tempol administration, MABF values significantly increased (p < 0.05). We observed significantly stronger PARP-positive staining in the lungs and kidney glomeruli in the CLP + saline group than in those of the sham-operated group (p(lung) = 0.0148, p(glomeruli) = 0.0025). A marked reduction in PARP activity was found in the lung and kidney glomeruli of the CLP + tempol group (p(lung) = 0.0026, p(glomeruli) = 0.0085). There was no significant effect of CLP on PARP activity in the liver and kidney tubuli (p(liver) > 0.05, p(tubuli) > 0.05).

CONCLUSION

Tempol improved MABF in a CLP-induced septic shock model. Although tempol could not prevent the activation of PARP in the liver and kidney tubuli, it did attenuate PARP activation in the lung and kidney glomeruli.

Nucleotide adsorption-desorption behaviour of boronic acid functionalized uniform-porous particles

In this study, nucleotide adsorption-desorption behaviour of boronic acid-carrying uniform, porous particles was investigated. The particles were produced by a "multi-step microsuspension polymerization" in the form of poly(styrene-vinylphenyl boronic acid-divinylbenzene) terpolymer. In the first step of the production method, uniform polystyrene latex particles (6.2 microm in size) were obtained by dispersion polymerization. These particles were first swollen by a low molecular mass organic agent (i.e. dibutylphthalate, DBP) and then by a monomer mixture including styrene (S), 4-vinylphenyl boronic acid (VPBA) and divinylbenzene (DVB). The particle uniformity was protected in both swelling stages by adjusting DBP/polystyrene latex and monomer mixture/polystyrene latex ratios. Polymerization of the monomer mixture in the swollen seed particles provided boronic acid-carrying uniform, porous particles 11-12 microm in size. To have uniform particles with different porosities and boronic acid contents, the feed concentration of boronic acid-carrying monomer and the monomer/seed latex ratio were changed. The particles were tried as sorbent for the adsorption of a model nucleotide (i.e., beta-nicotinamide adenine dinucleotide, beta-NAD). In the beta-NAD adsorption experiments, the maximum equilibrium adsorption was obtained at pH 8.5 which was very close to pKa of boronic acid. The incorporation of boronic acid functionality provided a significant increase in the beta-NAD adsorption. In contrast to plain poly(styrene-co-divinylbenzene) particles, four-fold higher beta-NAD adsorption was obtained with the boronic acid functionalized particles. Beta-NAD was desorbed from the particles with the yields higher than 90% by weight.

Thermally reversible VPBA-NIPAM copolymer gels for nucleotide adsorption

A thermosensitive gel matrix was prepared by free radical copolymerization of N-isopropylacrylamide (NIPAM) with a boronic acid-carrying monomer (i.e. 4-vinylphenylboronic acid, VPBA). The synthesis of the gel was performed at 70 degrees C in an alcohol-water mixture, using azobisisobutyronitrile and methylenebisacrylamide as the initiator and the crosslinker, respectively. To produce thermosensitive gels with a higher diol-binding affinity, an amino-containing comonomer, N-[3-(dimethylamino)propyl]methacrylamide (DMAPM) was included in the gel formation recipe. Thermally reversible VPBA-NIPAM and VPBA-DMAPM-NIPAM gels with different swelling properties were obtained by changing the feed concentrations of VPBA and DMAPM. To test the usability of the produced gels as sorbents in nucleotide adsorption, beta-nicotinamide adenine dinucleotide (beta-NAD) was selected as a model biomolecule. Then the adsorption isotherm for beta-NAD was obtained at +4 degrees C in HEPES buffer medium with a pH of 8.5. The support material was in a highly swollen form under these conditions, due to its thermosensitive character. This property was then used to enhance beta-NAD adsorption onto the gel matrix. Equilibrium adsorption capacities up to 70 mg beta-NAD/g dry gel could be achieved with the thermosensitive support prepared with the 12.9 mol% VPBA feed. The gels produced with higher VPBA and DMAPM feed concentrations exhibited higher equilibrium adsorption capacities for beta-NAD.

DNA adsorption onto polyethylenimine-attached poly(p-chloromethylstyrene) beads

In this study, DNA adsorption properties of polyethylenimine (PEI)-attached poly(p-chloromethylstyrene) (PCMS) beads were investigated. Spherical beads with an average size of 186 microm were obtained by the suspension polymerization of p-chloromethylstyrene conducted in an aqueous dispersion medium. Owing to the reasonably rough character of the bead surface, PCMS beads had a specific surface area of 14.1 m2/g. PEI chains could be covalently attached onto the PCMS beads with equilibrium binding capacities up to 208 mg PEI/g beads, via a direct chemical reaction between the amine and chloromethyl groups. After PEI adsorption with 10% (w/w) initial PEI concentration, free amino content of PEI-attached PCMS beads was determined as 0.91 mequiv./g. PEI-attached PCMS beads were utilized as sorbents in DNA adsorption experiments conducted at +4 degrees C in a phosphate buffer medium of pH 7.4. DNA immobilization capacities up to 290 mg DNA/g beads could be achieved with the tried sorbents. This value was approximately 50-times higher relative to the adsorption capacities of previously examined sorbents.

The value of percent free prostate specific antigen, prostate specific antigen density of the whole prostate and of the transition zone in Turkish men

INTRODUCTION

This study was undertaken to evaluate the value of percent free prostate specific antigen (PSA), PSA density of the whole prostate (PSAD) and of the transition zone (TZPSAD) in reducing unnecessary biopsies in Turkish men with serum PSA levels between 2.5 and 20 ng/mL.

MATERIALS AND METHODS

A total of 105 patients referred for early prostate cancer detection or lower urinary tract symptoms participated in the study. All patients had serum total PSA level, PSAD, total prostate volume, and rectal examination, 43 patients had serum free PSA level, and 65 patients had TZPSAD. Using transrectal ultrasound, sextant biopsy and two additional transitional zone biopsies were performed. The value of percent PSA, PSAD, and TZPSAD in reducing unnecessary biopsies was evaluated.

RESULTS

Prostate carcinoma was detected in 25 of 105 patients (23.8%). Overall, areas under the ROC curves for percent free PSA, PSAD, and TZPSAD were 0.553, 0.595, and 0.550, respectively. In patients with a benign rectal examination, the value of percent free PSA slightly increased. On the other hand, in patients with prostate volume smaller than 50 cc, the value of percent free PSA and TZPSAD was encouraging. Areas under the ROC curves for percent free PSA, and TZPSAD were 0.615 and 0.642 respectively.

CONCLUSION

In Turkish men with intermediate serum PSA concentrations, percent free PSA, PSAD, and TZPSAD are poor predictors of biopsy outcome, whereas in the prostate smaller than 50 cc, percent free PSA and TZPSAD provide additional information. This may reflect ethnic differences between this population and those reported in other series.

Cartilage shaping using the Er:YAG laser: preliminary report

Cartilage grafts have been widely used for reconstruction of congenital or acquired deformities. Reshaping and preserving the new shape of the cartilage grafts have been a problem. In this in vitro experimental study the authors studied the effect of the Er:YAG laser on cartilage reshaping in comparison with scalpel stripping and suture holding. The study consisted four groups (n = 9): group I, untouched cartilage; group II, the short edges of the cartilage were sutured to each other; group III, cartilage was incised using a scalpel; and group IV, Er:YAG laser stripping was applied to the cartilage. Changes in the shape of cartilage were evaluated at 15 minutes, and days 1, 4, and 10. The majority of cartilage in the scalpel-stripped group returned to the initial shape by day 10, whereas the laser-stripped cartilage showed progressive warping day by day, and almost all cartilage formed a circle by day 10. The Er:YAG laser enhanced cartilage warping by a mechanical effect of stripping and a thermal effect of laser radiation resulting in ultrastructural changes.

Late and long-standing capsular hematoma after aesthetic breast augmentation with a saline-filled silicone prosthesis: A case report

Late capsular hematoma is an extremely rare complication after the implantation of silicone breast prostheses for aesthetic or reconstructive objectives. We present a unique case of late capsular hematoma in an aesthetic breast augmentation with a saline-filled, textured silicone implant, which remained for a year after formation.

Cibacron blue F3G-A-attached uniform and macroporous poly(styrene-co-divinylbenzene) particles for specific albumin adsorption

Cibacron blue F3G-A-carrying uniform macroporous particles were proposed as an alternative sorbent for specific albumin adsorption. These particles were produced by a multistep polymerization procedure. In the first step of production, the uniform polystyrene seed particles were prepared by a dispersion polymerization method. Next. the polystyrene seed particles were first swollen by dibutylphthalate and then by styrene-divinylbenzene mixture in an aqueous emulsion medium. In the last step (i.e. repolymerization), styrene-divinylbenzene mixture was copolymerized within the swollen seed particles in the absence or presence of a stabilizer (e.g. poly(vinyl alcohol)). Although a considerable amount of non-specific BSA adsorption was observed on the surface of the particles produced in the absence of PVA, zero non-specific albumin adsorption could be achieved with the uniform macroporous particles produced in the presence of PVA. The stabilizer on the particle surface was also used as a ligand in the further derivatization of macroporous particles for specific albumin adsorption. Cibacron blue F3G-A was then covalently attached onto the surface of uniform macroporous particles. Specific albumin adsorption capacities up to 93 mg g(-1) could be achieved with the cibacron blue F3G-A-carrying macroporous particles of 6.25 microm in size.