Gram-scale purification of phosphorothioate oligonucleotides using ion-exchange displacement chromatography.

The purification of oligonucleotides by ion-exchange displacement chromatography is demonstrated on the gram-scale. Using a 50 mmD x 100 mmL (203 ml) column operated in the displacement mode, 1.2 g of a 24mer phosphorothioate oligonucleotide was purified. Product yield for this separation was 70% (780 mg) at a purity of 96.4% and the mass balance recovery of all oligonucleotide was 97.5%. The displacement purification of four additional phosphorothioate oligonucleotides ranging in length from 18 to 25 bases is also demonstrated on the semi-preparative (10-50 mg) scale. All of these oligonucleotides were purified using similar displacement conditions and typical results were 60% yield at 96% purity. The displacement portion of these separations required <15 min and total cycle time including equilibration, feed loading and regeneration can be performed in under 30 min. These results seem to indicate that displacement chromatography may be amenable to generalizations in separation protocol that would greatly reduce the effort required to obtain an optimized purification scheme for moderately long oligonucleotides.     

Glucose oxidase-rich Aspergillus niger strain,cost-effective protocol and an economical substrate for the preparation of tablet grade calcium gluconate

Summary An optimized 25 litre scale protocol for the submerged batchwise preparation and recovery of calcium gluconate is devised. The optimal parameters of production envisaged the use of (a) glucose oxidase-rich Aspergillus niger strain, (b) salts-fortified high DE starch hydrolysate as the production medium, (c) pH 6.5 ± 0.1, 29 ± 1°C, 250 ± 10 rpm, (d) 1.0–1.5 vvm rate of aeration over 24 ± 2 h duration and (e) intermittant neutralization with calcium carbonate. The recovery protocol comprised of (a) charcoal decolourisation (2%, 60°C, l h), (b) filtration and methanol-aided precipitation, (c) centrifugation (700 g, 27°C), (d) vacuum drying (700 mm of Hg, 45°C) and (e) pulverization to provide 80% recovery of calcium gluconate, passing Indian/British pharmacopoeial specifications for the tablet grade preparation.     

l-Myoinositol-1-phosphate synthase from Neurospora crassa: Purification to homogeneity and partial characterization

The purification procedure of milligram quantities of stable myoinositol-1-phosphate synthase (EC 5.5.1.4) from Neurospora crassa is reported. The procedure includes: (a) (NH₄)₂SO₄ and protamine sulfate precipitations, (b) gel filtration in Ultrogel AcA-34 (LKB), (c) DEAE-cellulose chromatography, (d) AH-Sepharose 4B chromatography, and (e) calcium phosphate gel chromatography. The enzyme is considered pure according to the following criteria: (a) gel filtration, (b) sucrose density gradient centrifugation, (c) polyacrylamide gel electrophoresis, and (d) isoelectric focusing technique. The molecular weight estimated by gel filtration chromatography and sucrose density gradient centrifugation is 345,000. The subunit molecular weight is 59,000. The active enzyme seems to posses an hexameric structure. The isoelectric point estimated for the pure enzyme is 5.2. The enzyme was optimally stimulated by 10 mm (NH₄)₂SO₄ and by 50 mm KCl, while NaCl had a minor inhibitory effect at higher concentrations. The divalent cations Mg²⁺ and Mn²⁺ were inhibitory only at nonphysiological concentrations. The enzymatic activity after the salt fractionation steps was about 33% NAD⁺ independent; but with purification the resulting homogeneous enzyme showed less than 5% NAD⁺-independent activity.     

Arginase attenuates inhibitory nonadrenergic noncholinergic nerve-induced nitric oxide generation and airway smooth muscle relaxation

Background

Recent evidence suggests that endogenous arginase activity potentiates airway responsiveness to methacholine by attenuation of agonist-induced nitric oxide (NO) production, presumably by competition with epithelial constitutive NO synthase for the common substrate, L-arginine. Using guinea pig tracheal open-ring preparations, we now investigated the involvement of arginase in the modulation of neuronal nitric oxide synthase (nNOS)-mediated relaxation induced by inhibitory nonadrenergic noncholinergic (iNANC) nerve stimulation.

Methods

Electrical field stimulation (EFS; 150 mA, 4 ms, 4 s, 0.5 – 16 Hz)-induced relaxation was measured in tracheal preparations precontracted to 30% with histamine, in the presence of 1 μM atropine and 3 μM indomethacin. The contribution of NO to the EFS-induced relaxation was assessed by the nonselective NOS inhibitor L-NNA (0.1 mM), while the involvement of arginase activity in the regulation of EFS-induced NO production and relaxation was investigated by the effect of the specific arginase inhibitor nor-NOHA (10 μM). Furthermore, the role of substrate availability to nNOS in EFS-induced relaxation was measured in the presence of various concentrations of exogenous L-arginine.

Results

EFS induced a frequency-dependent relaxation, ranging from 6.6 ± 0.8% at 0.5 Hz to 74.6 ± 1.2% at 16 Hz, which was inhibited with the NOS inhibitor L-NNA by 78.0 ± 10.5% at 0.5 Hz to 26.7 ± 7.7% at 8 Hz (P < 0.01 all). In contrast, the arginase inhibitor nor-NOHA increased EFS-induced relaxation by 3.3 ± 1.2-fold at 0.5 Hz to 1.2 ± 0.1-fold at 4 Hz (P < 0.05 all), which was reversed by L-NNA to the level of control airways in the presence of L-NNA (P < 0.01 all). Similar to nor-NOHA, exogenous L-arginine increased EFS-induced airway relaxation (P < 0.05 all).

Conclusion

The results indicate that endogenous arginase activity attenuates iNANC nerve-mediated airway relaxation by inhibition of NO generation, presumably by limiting L-arginine availability to nNOS.     

Improving the large scale purification of the HIV microbicide,griffithsin

Background

Griffithsin is a broad spectrum antiviral lectin that inhibits viral entry and maturation processes through binding clusters of oligomannose glycans on viral envelope glycoproteins. An efficient, scaleable manufacturing process for griffithsin active pharmaceutical ingredient (API) is essential for particularly cost-sensitive products such as griffithsin -based topical microbicides for HIV-1 prevention in resource poor settings. Our previously published purification method used ceramic filtration followed by two chromatography steps, resulting in a protein recovery of 30%. Our objective was to develop a scalable purification method for griffithsin expressed in Nicotiana benthamiana plants that would increase yield, reduce production costs, and simplify manufacturing techniques. Considering the future need to transfer griffithsin manufacturing technology to resource poor areas, we chose to focus modifying the purification process, paying particular attention to introducing simple, low-cost, and scalable procedures such as use of temperature, pH, ion concentration, and filtration to enhance product recovery.

Results

We achieved >99% pure griffithsin API by generating the initial green juice extract in pH 4 buffer, heating the extract to 55°C, incubating overnight with a bentonite MgCl₂ mixture, and final purification with Capto™ multimodal chromatography. Griffithsin extracted with this protocol maintains activity comparable to griffithsin purified by the previously published method and we are able to recover a substantially higher yield: 88 ± 5% of griffithsin from the initial extract. The method was scaled to produce gram quantities of griffithsin with high yields, low endotoxin levels, and low purification costs maintained.

Conclusions

The methodology developed to purify griffithsin introduces and develops multiple tools for purification of recombinant proteins from plants at an industrial scale. These tools allow for robust cost-effective production and purification of griffithsin. The methodology can be readily scaled to the bench top or industry and process components can be used for purification of additional proteins based on biophysical characteristics.     

Large scale purification protocol for carnocin KZ 213 from Carnobacterium piscicola

Large scale purification of a class IIa bacteriocin has been developed to recover pure carnocin KZ 213 produced by Carnobacterium piscicola 213. Most previous protocols reported in the literature for the purification of small peptides have used reversed phase chromatography but scale-up is difficult. The first step of this new protocol is hydrophobic interaction chromatography, the second and third steps are cation exchange chromatography. The protocol leads to a complete recovery of carnocin KZ 213 with 95% purity and to a concentration factor of 83. From 10 l culture supernatant, 5.8 mg carnocin KZ 213 have been produced with a specific activity of 8,500 UA g⁻¹. The protocol is easy to implement for larger volumes.     

Cloning, expression and purification of DNA-binding protein Mvo10b from Methanococcus voltae

Mvo10b from the mesophilic archaeon Methanococcus voltae is a member of the Sac10b family which may play an important role in the organization and accessibility of genetic information in Archaea. Since Mvo10b is a DNA-binding protein as the other member in the Sac10b family, to obtain a recombinant Mvo10b requires an efficient and inexpensive expression and purification system for producing the protein free of nucleic acid contamination. Previously, the hyperthermophilic archaeal Ssh10b of the Sac10b family was successfully purified. However, the protocol adopted to purify Ssh10b is not appropriate for purifying the mesophilic Mvo10b. This study describes the successful expression and purification of the recombinant Mvo10b. The expression of recombinant Mvo10b was carried out in Escherichia coli, and the target protein was expressed in the soluble form. The protein was purified by polyethyleneimine (PEI) precipitation followed by nickel ion metal affinity chromatography. The purity of Mvo10b was checked to insure being free of nucleic acid contamination. The final protein yield is about 30 mg/l of LB culture. The ensemble of NMR and far-UV CD data shows that the purified Mvo10b has abundant regular secondary structures and is correctly folded, which may have similar 3D structure as its hyperthermophilic counterpart [P62A]Ssh10b. The developed protocol has potential application in the production of the other thermophilic and mesophilic proteins in the Sac10b family.     

A 50 000-dalton anorexigenic protein from urine

A potent, homogeneous, 50 kDa protein which transiently depresses food intake of rats up to 24 h after injection was isolated from rat urine. It was prepared from an ethanolic benzoic acid precipatate of urine. The material was subjected to DEAE-Sephacel chromatography, whereupon four fractions (DEAE pools a, b, c, and d) were obtained. The latter three contained anorexigenic activity. DEAE pools b and c were subjected to further purification on colums of Sephacryl S-300 eluted with buffer containing 8 M urea. One of the subfractions of DEAE pool b contained only one protein as judged by polyacrylamide gel electrophoresis in sodium dodecyl sulfate. This protein had a molecular weight of 50,000 and was active in reducing 24 h food intake at a dose of 130 μg/100 g bodyweight.     

Hydrophobic-interaction chromatography and anion-exchange chromatography in the presence of acetonitrile. A two-step purification method for human prolactin

Described is a two-chromatographic-step preparative-scale technique for the purification of human prolactin from a frozen pituitary homogenate. The method utilizes hydrophobic interaction chromatography on the mildly hydrophobic adsorbent phenyl-Sepharose CL-4B and anion-exchange chromatography on DEAE-cellulose in the presence of acetonitrile. Human prolactin was solubilized at pH10.0 after a prior extraction of pituitaries at pH4.0, the acid pH being ineffective at solubilizing human prolactin but capable of solubilizing large amounts of interfering protein. An 11-fold increase in the potency of the solubilized human prolactin was achieved in this manner. Prolactin could be adsorbed to phenyl-Sepharose at low ionic strengths (I<0.01); few other proteins were adsorbed under these conditions. This is a demonstration of the hydrophobic nature of human prolactin. The amount of phenyl-Sepharose was limited to the minimum (35mg of protein/g of phenyl-Sepharose) necessary to adsorb human prolactin, further reducing the uptake of other pituitary protein. Desorption was achieved by using an acetonitrile gradient (0–30%, v/v), resulting in a purification of human prolactin of 85-fold and recovery of 78%. Acetonitrile (20%, v/v) was also included in all buffers for DEAE-cellulose chromatography, increasing the resolution and recovery of human prolactin, apparently by minimizing non-ionic interactions with the matrix. Prolactin (10mg) was recovered from 63g if pituitaries, an overall recovery of 58%. It was homogeneous by gel filtration and sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, contained less than 0.1% somatotropin (growth hormone), on iodination demonstrated more than 95% binding to excess anti-(human prolactin) serum and could be displaced from anti-(human prolactin) serum in a manner indistinguishable from the serum of a patient with a human prolactin-secreting adenoma.     

Rapid Purification of Recombinant Histones

The development of methods to assemble nucleosomes from recombinant histones decades ago has transformed chromatin research. Nevertheless, nucleosome reconstitution remains time consuming to this day, not least because the four individual histones must be purified first. Here, we present a streamlined purification protocol of recombinant histones from bacteria. We termed this method “rapid histone purification” (RHP) as it circumvents isolation of inclusion bodies and thereby cuts out the most time-consuming step of traditional purification protocols. Instead of inclusion body isolation, whole cell extracts are prepared under strongly denaturing conditions that directly solubilize inclusion bodies. By ion exchange chromatography, the histones are purified from the extracts. The protocol has been successfully applied to all four canonical Drosophila and human histones. RHP histones and histones that were purified from isolated inclusion bodies had similar purities. The different purification strategies also did not impact the quality of octamers reconstituted from these histones. We expect that the RHP protocol can be readily applied to the purification of canonical histones from other species as well as the numerous histone variants.     

Distribution of cell surface saccharides on pancreatic cells

We describe here a simple, general procedure for the purification of a variety of lectins, and for the preparation of lectin-ferritin conjugates of defined molar composition and binding properties to be used as probes for cell surface saccharides. The technique uses a “universal” affinity column for lectins and their conjugates, which consists of hog sulfated gastric mucin glycopeptides covalently coupled to agarose. The procedure involes: (a) purification of lectins by chromatography of aqueous extracts of seeds or other lectin-containing fluids over the affinity column, followed by desorption of the desired lectin with its hapten suge; (b) iodination of the lectin to serve as a marker during subsequent steps; (c) conjugation of lectin to ferritin with glutaraldehyde; (d) collection of active lectin-ferritin conjugates by affinity chromatography; and (e) separation of monomeric lectin-ferritin conjugates from larger aggregates and unconjugated lectin by gel chromatography. Based on radioactivity and absorbancy at 310 nm for lectin and ferritin, respectively, the conjugates consist of one to two molecules of lectin per ferrritin molecule. Binding studies of native lectins and their ferritin conjugates to dispersed pancreatic acinar cells showed that the conjugation procedure does not significantly alter either the affinity constant of the lectin for its receptor on the cell surface or the number of sites detected.     

A Procedure for Human Pregnancy Zone Protein (and Human α2-Macroglobulin) Purification Using Hydrophobic Interaction Chromatography on Phenyl–Sepharose CL-4B Column

In the present work we describe a procedure for the purification of human pregnancy zone protein (PZP) from pooled late pregnancy plasma by using hydrophobic interaction chromatography (HIC) on a phenyl–Sepharose column. The HIC step allowed the complete isolation of haptoglobins and the partial separation of human α₂-macroglobulin (α₂-M) from a protein fraction containing PZP previously obtained by a DEAE-Sephacel chromatography. Pure and native PZP, with a recovery of nearly 25% and biological activity of protease-binding, was obtained by two definitive final steps consisting of zinc-chelate and size-filtration chromatographies. Moreover, we further present an alternative procedure for the purification of α₂-M from the same pregnancy plasma, based on the differential elution of PZP and α₂-M from the HIC. This purification step gave rise to a highly purified product with a recovery of 10%. This differential elution could be explained by differences in surface hydrophobicity observed between both proteins. In addition, considering the different hydrophobic properties exhibited by native PZP and PZP–protease complexes, HIC on phenyl–Sepharose column could also be used for separating both conformational states of PZP.     

Sample purification using a C18-bonded reversed-phase cartridge for the quantitative analysis of corticosteroids in adrenal cell cultures by high-performance liquid chromatography or gas chromatography—mass spectrometry

Quantitative extraction and subsequent purification of small biological samples often involve cumbersome procedures. We have devised a short and efficient method for the quantitative extraction of the corticosteroid and the 20α reduced steroid series from culture medium containing 20% sera in a single, pure fraction with separation from cholesterol. Passage through a C₁₈-bonded reversed-phase Sep-Pak^® cartridge of the acidified culture medium and subsequent extraction of the steroid fraction with methanol yields a single fraction containing all steroids in 90% recovery and reduced quantities of cholesterol down to 30%. The extract can then be used without further purification for quantitative analysis by high-performance liquid chromatography or derivatized and analyzed by gas chromatography and gas chromatography—mass spectrometry.     

Purification of human IgG by negative chromatography on ω-aminohexyl-agarose

The ω-aminohexyl diamine immobilized as ligand on CNBr- and bisoxirane-activated agarose gel was evaluated for the purification of human immunoglobulin G (IgG) from serum and plasma by negative affinity chromatography. The effects of matrix activation, buffer system, and feedstream on recovery and purity of IgG were studied. A one-step purification process using Hepes buffer at pH 6.8 allowed a similar recovery (69–76%) of the loaded IgG in the nonretained fractions for both matrices, but the purity was higher for epoxy-activated gel (electrophoretically homogeneous protein with a 6.5-fold purification). The IgG and human serum albumin (HSA) adsorption equilibrium studies showed that the adsorption isotherms of IgG and HSA obeyed the Langmuir–Freundlich and Langmuir models, respectively. The binding capacity of HSA was high (210.4 mg mL^?1 of gel) and a positive cooperativity was observed for IgG binding. These results indicate that immobilizing ω-aminohexyl using bisoxirane as coupling agent is a useful strategy for rapid purification of IgG from human serum and plasma.     

Optimized protocol for the pilot-scale preparation of fungal cellulase

Summary A 25-l scale protocol is devised for the optimal secretion and recovery of fungal cellulase. Using a selected higher yieldingTrichoderma viride SMC strain, a protocol consisted of: a) an optimized production medium rich in microcrystalline cellulose (MCC), fortified with 1% (w/v) ammonium sulphate, 0.5% (w/v) soybean flour, 0.1% (v/v) Tween-80 and other trace nutrients; b) optimized physical parameters of production, such as an inoculum containing a homogeneous suspension of 6×10⁷ conidia per 1,28±1°C, pH 4.0±0.5, 300±20 rpm, 11000±1000 l/h aeration, and 170–220 h duration; c) optimal recovery through a filter press (450 l/h rate of filtration) followed by precipitation with 2.5–3.0 volumes of acetone (15°C and basket centrifugation (27°C, 1700 rpm)); and d) vacuum drying (35°C, 4–6 h). This afforded 70% recovery of cellulase in the form of white fluffy powder containing 20000±2000 carboxy methyl cellulase and 1000±50 units filter paperase per g activities, with raw material cost of US$ 8–10 per million carboxy methyl cellulase units. During storage for 18 months at 4°C, ambient temperature and 37°C, the cellulase preparation was found to retain 100, 75 and 60% of its initial activity, respectively.     

Development of purification process for dual‐function recombinant human heavy‐chain ferritin by the investigation of genetic modification impact on conformation

Ferritin is a promising drug delivery platform and has been functionalized through genetic modifications. This work has designed and expressed a dual‐functional engineered human heavy‐chain ferritin (HFn) with the inserted functional peptide PAS and RGDK to extend half‐life and improve tumor targeted drug delivery. A facile and cost‐effective two‐step purification pathway for recombinant HFn was developed. The genetic modification was found to affect HFn conformation, and therefore varied the purification performance. Heat‐acid precipitation followed by butyl fast flow hydrophobic interaction chromatography (HIC) has been developed to purify HFn and modified HFns. Nucleic acid removal reached above 99.8% for HFn and modified HFns. However, HFn purity reached above 95% and recovery yield (overall) above 90%, compared with modified HFns purity above 82% and recovery yield (overall) above 58%. It is interesting to find that the inserted functional peptides significantly changed the molecule conformation, where a putative turnover of the E‐helix with the inserted functional peptides formed a “flop” conformation, in contrast with the “flip” conformation of HFn. It could be the cause of fragile stability of modified HFns, and therefore less tolerant to heat and acid condition, observed by the lower recovery yield in heat‐acid precipitation.     

Routine manufacture of recombinant proteins using expanded bed adsorption chromatography

Two different recombinant human proteins were purified directly from Pichia pastoris whole cell fermentation broth, containing 30–44% biomass (wet weight percent), by strong cation exchange expanded bed adsorption chromatography. Expanded bed adsorption chromatography provided clarification, product purification and product concentration in a single unit operation at large scale (2000-l nominal fermentation volume). The efficiency of expanded bed adsorption chromatography resulted in a short process time, high process yield, and limited proteolytic degradation of the target proteins. The separations were operated using a 60-cm (d) column run at 14 l/min. For one protein, expanded bed adsorption chromatography resulted in an average product recovery of 113% (relative to fermentation supernatant) and a purity of 89% (n=10). For the other protein, the average product recovery was 99% (relative to fermentation supernatant) and the purity was 62.1 (n=10). Laboratory experiments showed that biomass reduced product dynamic binding capacity for protein 2.     

Three Minutes of All-Out Intermittent Exercise per Week Increases Skeletal Muscle Oxidative Capacity and Improves Cardiometabolic Health

We investigated whether a training protocol that involved 3 min of intense intermittent exercise per week — within a total training time commitment of 30 min including warm up and cool down — could increase skeletal muscle oxidative capacity and markers of health status. Overweight/obese but otherwise healthy men and women (n = 7 each; age  = 29±9 y; BMI  = 29.8±2.7 kg/m²) performed 18 training sessions over 6 wk on a cycle ergometer. Each session began with a 2 min warm-up at 50 W, followed by 3×20 s “all-out” sprints against 5.0% body mass (mean power output: ∼450–500 W) interspersed with 2 min of recovery at 50 W, followed by a 3 min cool-down at 50 W. Peak oxygen uptake increased by 12% after training (32.6±4.5 vs. 29.1±4.2 ml/kg/min) and resting mean arterial pressure decreased by 7% (78±10 vs. 83±10 mmHg), with no difference between groups (both p<0.01, main effects for time). Skeletal muscle biopsy samples obtained before and 72 h after training revealed increased maximal activity of citrate synthase and protein content of cytochrome oxidase 4 (p<0.01, main effect), while the maximal activity of β-hydroxy acyl CoA dehydrogenase increased in men only (p<0.05). Continuous glucose monitoring measured under standard dietary conditions before and 48–72 h following training revealed lower 24 h average blood glucose concentration in men following training (5.4±0.6 vs. 5.9±0.5 mmol/L, p<0.05), but not women (5.5±0.4 vs. 5.5±0.6 mmol/L). This was associated with a greater increase in GLUT4 protein content in men compared to women (138% vs. 23%, p<0.05). Short-term interval training using a 10 min protocol that involved only 1 min of hard exercise, 3x/wk, stimulated physiological changes linked to improved health in overweight adults. Despite the small sample size, potential sex-specific adaptations were apparent that warrant further investigation.     

EFFECT OF THE NUMBER OF SPRINT REPETITIONS ON THE VARIATION OF BLOOD LACTATE CONCENTRATION IN REPEATED SPRINT SESSIONS

The aim of the present study was to examine the effect of number of sprint repetitions on the variation of blood lactate concentration (blood [La]) during different repeated-sprint sessions in order to find the appropriate number of sprint repetitions that properly simulates the physiological demands of team sport competitions. Twenty male team-sport players (age, 22.2 ± 2.9 years) performed several repeated-sprint sessions (RSS) consisting of 1, 2, 3, 4, 5, 9, or 10 repetitions of 30 m shuttle sprints (2 × 15 m) with 30 s recovery in between. The blood [La] was obtained after 3 min of recovery at the end of each RSS. The present study showed that for RSS of 3 sprints (RSS3) there was a high increase (p<0.001) in blood [La], which reached approximately fivefold resting values (9.4±1.7 mmol · l⁻¹) and then remained unchanged for the RSS of 4 and 5 sprints (9.6±1.4 and 10.5±1.9 mmol · l⁻¹, p=0.96 and 0.26, respectively). After RSS9 and RSS10 blood [La] further significantly increased to 12.6 and 12.7 mmol · l⁻¹, p<0.001, respectively. No significant difference was found between RSS3, RSS4 and RSS5 for the percentage of sprint speed decrement (Sdec) (1.5±1.2; 2.0±1.1 and 2.6±1.4%, respectively). There was also no significant difference between RSS9 and RSS10 for Sdec (3.9±1.3% and 4.5±1.4%, respectively). In conclusion, the repeated-sprint protocol composed of 5 shuttle sprint repetitions is more representative of the blood lactate demands of the team sports game intensity.