Integration of mechanical cell disruption and fluidised bed recovery of G3PDH from unclarified disrupted yeast: A comparative study of the performance of unshielded and polymer shielded dye-ligand chromatography systems

The development of a simplified process for the simultaneous disruption and direct selective purification of intracellular proteins from unclarified yeast disruptate has been investigated. The recovery of glyceraldehyde 3-phosphate dehydrogenase (G3PDH) from baker's yeast was selected as a potential demonstration of the generic applicability and practical feasibility of this integrated technique. The application of an adsorbent characterised by high density (UpFront steel-agarose; rho=2.65g ml(-1)) facilitated the combining of cell disruption operation (bead milling of 50% ww/v of yeast suspension at 7.2 lh(-1)) with fluidised bed dye-ligand (Cibacron Blue 3GA) adsorption operated immediately downstream of the disrupter. The adoption of a polymer shielded, dye-ligand technique advanced recovery efficiency. It was demonstrated that G3PDH could be recovered with a yield of 67.5% bound activity and a specific activity of 40.2IU mg(-1), after a single step elution with 0.15M NaCl. The generic application of this approach has been evaluated.

Purification of recombinant nucleocapsid protein of Newcastle disease virus from unclarified feedstock using expanded bed adsorption chromatography

In the present work, a single-step purification of recombinant nucleocapsid protein (NP) of the Newcastle disease virus (NDV) directly from unclarified feedstock using an expanded bed adsorption chromatography (EBAC) was developed. Streamline 25 column (ID = 25 mm) was used as a contactor and Streamline chelating adsorbent immobilized with Ni2+ ion was used as affinity adsorbent. The dynamic binding capacity of Ni2+ -loaded Streamline chelating adsorbent for the NP protein in unclarified feedstock was found to be 2.94 mg ml(-1) adsorbent at a superficial velocity of 200 cm h(-1). The direct purification of NP protein from unclarified feedstock using expanded bed adsorption has resulted in a 31% adsorption and 9.6% recovery of NP protein. The purity of the NP protein recovered was about 70% and the volume of processing fluid was reduced by a factor of 10. The results of the present study show that the IMA-EBAC developed could be used to combine the clarification, concentration and initial purification steps into a single-step operation.

Process intensification of fluidized bed dye-ligand adsorption of G3PDH from unclarified disrupted yeast: A case study of the performance of a high-density steel–agarose pellicular adsorbent

The development of a process intensified primary capture step for the direct selective recovery of intracellular proteins from very dense particulate-containing yeast extract has been explored. The purification of glyceraldehyde 3-phosphate dehydrogenase from bakers' yeast was chosen as a potential demonstration of this approach. A high throughput (50%, w/v, yeast extracts at a superficial linear velocity of 450 cm h(-1)) was achieved by adoption of a high-density adsorbent (UpFront steel-agarose; rho = 2.65 g ml(-1)) derivatized with selective ligand chemistries (Cibacron Blue 3GA). This should ultimately minimize adsorption time and maximize process efficiency of fluidized bed adsorption.

Comparative evaluation of three purification methods for the nucleocapsid protein of Newcastle disease virus from Escherichia coli homogenates

In the present study, the performances of conventional purification methods, packed bed adsorption (PBA), and expanded bed adsorption (EBA) for the purification of the nucleocapsid protein (NP) of Newcastle disease virus (NDV) from Escherichia coli homogenates were evaluated. The conventional methods for the recovery of NP proteins involved multiple steps, such as centrifugation, precipitation, dialysis, and sucrose gradient ultracentrifugation. For the PBA, clarified feedstock was used for column loading, while in EBA, unclarified feedstock was used. Streamline chelating immobilized with Ni2+ ion was used as an affinity ligand for both PBA and EBA. The final protein yield obtained in conventional and PBA methods was 1.26% and 5.56%, respectively. It was demonstrated that EBA achieved the highest final protein yield of 9.6% with a purification factor of 7. Additionally, the total processing time of the EBA process has been shortened by 8 times compared to that of the conventional method.

Purification of filamentous bacteriophage M13 by expanded bed anion exchange chromatography

In this paper, we investigated the development of a simplified and rapid primary capture step for the recovery of M13 bacteriophage from particulate-containing feedstock. M13 bacteriophage, carrying an insert, was propagated and subsequently purified by the application of both conventional multiple steps and expanded bed anion exchange chromatography. In the conventional method, precipitation was conducted with PEG/NaCl, and centrifugation was also performed. In the single step expanded bed anion exchange adsorption, UpFront FastLine 20 (20 mm i.d.) from UpFront Chromatography was used as the contactor, while 54 ml (Ho = 15 cm) of STREAMLINE DEAE (rho = 1.2 g/cm3) from Amersham Pharmacia Biotechnology was used as the anion exchanger. The performance of the two methods were evaluated, analysed, and compared. It was demonstrated that the purification of the M13 bacteriophage, using expanded bed anion exchange adsorption, yielded the higher recovery percentage, at 82.86%. The conventional multiple step method yielded the lower recovery percentage, 36.07%. The generic application of this integrated technique has also been assessed.

A questionnaire survey of attitudes to and usage of sunscreens in northwest England

BACKGROUND/PURPOSE

Sunscreens are employed with the aim of reducing the deleterious effects of ultraviolet radiation (UVR), but little is known about their use in the UK.

METHODS

This questionnaire survey assessed attitudes to and usage of sunscreens in northwest England in 2000. Subjects (186 females and 102 males) were recruited from the waiting rooms of four general practices, with a high response rate of 97%.

RESULTS

Females were more frequent users of sunscreens than males, but only 35% females and 8% males reported their regular use. Twenty-two per cent of the study population did not use sunscreens at all, whereas 66% of subjects bought a sunscreen product once a year or less. Thirty-four per cent subjects reported experiencing sunburn in the last 2 years. Interestingly, more (60%) sunburns were found to occur at home in the UK than on holidays abroad, and these frequently occurred during outdoor activities other than deliberate sunbathing.

CONCLUSION

There remains much scope for sunscreen education in the British public.

Direct enzyme adsorption from an unclarified microbial feedstock using suspended bed chromatography

Suspended bed chromatography (SBC) is a new hybrid technique concomitantly benefiting from batch adsorption, the process advantages of an enclosed system, and its compatibility with established commercial chromatographic contactors and adsorbents. SBC was evaluated in the anion-exchange capture and chromatographic fractionation of native glyceraldehyde-3-phosphate dehydrogenase (G3PDH) from the complex mixture of molecular and particulate moieties that constitute wet-milled bakers' yeast. Method scouting established operating conditions exploiting Whatman Express-Ion Exchanger Q at pH 7.5 and a disrupted biomass concentration equivalent to 3.5% (wet mass/v original intact cells). Partially purified G3PDH was recovered directly from the yeast disruptate in a scaled-down process developed at 1/756 process scale. This was used to establish operating parameters to facilitate process scale-up to exploit a 44 cm I.D. Millipore IsoPak column, 18 kg (swollen mass) of Express-Ion Q anion-exchange cellulose and 275 1 of 3.5% (wet w/v) bakers' yeast disruptate. The generic utility of SBC was demonstrated for direct product adsorption from feedstocks characterised by a modest content of bioparticulates (equivalent to < 4% (wet w/v) disrupted cells). Analyses illustrated an enrichment of G3PDH in respect of enzyme concentration and significant reduction in product turbidity and Pico-Green reactivity (correlated with double stranded (ds) DNA content). The application niche for this new approach to primary protein recovery is discussed with particular reference to the downstream processing of coarsely clarified whole broths, cell disruptates and biological extracts.

Keloidal scleroderma

A 53-year-old woman with systemic sclerosis developed numerous cutaneous nodules, resembling keloids, on her anterior chest wall. The nodules failed to respond to therapy with topical steroid, calcipotriol, or extended photochemotherapy. This is a rare, disfiguring variant of scleroderma, unresponsive to treatment, and poorly understood.

What do trainee hairdressers know about hand dermatitis?

Hand dermatitis is an important cause of morbidity in hairdressers. We conducted a questionnaire survey of 121 trainee hairdressers from 2 hairdressing colleges in Burnley (UK). The questionnaire concerned the number and types of hairdressing procedures performed, previous and current medical history, awareness of risks to the skin from hairdressing, and knowledge of hand dermatitis prevention. 17% of the trainees suffered currently from hand dermatitis. This is likely to be due to the large amount of wet work done by apprentice hairdressers, particularly those who worked in salons. 2/3 of trainees were not aware that atopic eczema predisposed to hand dermatitis. Formal pre-school and pre-employment counselling was limited. Knowledge on hand care among trainees was not often translated into practice, with gloves being worn by only 9% when shampooing and 58% when perming. Prevention of hand dermatitis by education and pre-employment counselling is of fundamental importance.

Epstein-Barr virus-positive blastoid nasal T/natural killer-cell lymphoma in a caucasian

T/natural killer (NK)-cell lymphoma is a subtype of non-Hodgkin's lymphoma, with frequent cutaneous involvement; it follows an aggressive course. Most cases are reported in Asia, and typically present with nasopharyngeal involvement. There is a distinct variant known as blastoid T/NK-cell lymphoma, which affects elderly, non-Asian patients, with absence of nasal involvement. We report a middle-aged caucasian man who had blastoid T/NK-cell lymphoma with nasal involvement.

PUVA therapy in lichen aureus

Lichen aureus is one of the subtypes of a rare group of diseases, pigmented purpuric dermatoses. The natural course of the disease is slow evolution and slow resolution. Treatment is generally limited. We report a case of lichen aureus that responded dramatically to photochemotherapy (PUVA).

Esophageal investigations in connective tissue disease: which tests are most appropriate?

Our aim was to review the use of esophageal investigations in patients with suspected connective tissue disease (CTD). Forty-seven patients (39 women and 8 men) with suspected CTD were referred for esophageal manometry at the gastrointestinal physiology unit in the Royal Victoria Hospital, Belfast, U.K., over a 10-year period (1987-1997). The mean age was 51.7 years (range = 21-79 years). Chart review was conducted 1 to 10 years after manometry to confirm the final diagnoses: scleroderma was found in 11; CREST (calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly, telangiectasia), 8; mixed connective tissue disease, 14; Raynaud's alone, 5; and other CTDs, 9. All 47 successfully underwent esophageal manometry. In addition to manometry, 24 underwent gastroscopy; 27, barium meal; and 3, esophageal pH studies. Clinically significant esophageal abnormalities were noted in 8 (33%) on gastroscopy, in 15 (56%) on barium meal, and in 31 (66%) on manometry. Gastroscopy had a significantly lower positivity rate than the others (p < 0.05). Only three patients had pH testing, yet all three pH tests were abnormal. During manometry, abnormal findings were significantly more common in scleroderma-CREST when compared with other diagnoses (89% vs. 50%; p < 0.02). Thirty-three patients reported dysphagia. Abnormal manometry was more likely in these cases (82% vs. 33%; p < 0.02). A high percentage of patients with CTD have significant esophageal motility disorders. Investigations were more likely to be positive with scleroderma-CREST than other CTDs, even if dysphagia was present. Barium meal and manometry are more useful than OGD. pH studies were under-used. There is need for a standardized approach to esophageal investigations in patients with CTDs.