Differential salt-promoted chromatography for protein purification.

A range of hydrophobic-type adsorbents for protein chromatography has been screened for the binding, at high salt concentrations, of 10 enzymes from a bacterial extract. Adsorbents were chosen for tandem chromatography, in which the first adsorbent removed much of the protein, and the second and subsequent columns bound the desired enzymes. Simple schemes for isolating Zymomonas mobilis and yeast alcohol dehydrogenases are described, in which the enzymes are affinity eluted by NAD+.     

Separation of insect hemolymph proteins by cascade-mode multi-affinity chromatography.

The hemolymph of the adult female Manduca sexta was fractionated by cascade-mode multi-affinity chromatography (CASMAC) on a main-line tandem column chain containing Zn(2+)-TED, T-gel, Ni(2+)-DPA, and phenylsepharose and a side-line column containing Zn(2+)-DPA. The technique separated some of the previously described major hemolymph proteins, and yielded a number of fractions with simple composition. Some of these fractions contained only less abundant proteins of Manduca hemolymph. Thus, it appears that CASMAC would be a very useful fractionation technique for purification and characterization of the minor proteins of insect hemolymph.     

A double enhancement of greening in the cotyledons of cucumber seedlings by excision and red light

Cotyledons excised without the hypocotyl hook from 6-day-old etiolated cucumber ( Cucumis sativus L. var. Elem) seedlings accumulated a significantly higher amount of chlorophyll than cotyledons excised with hooks or intact cotyledons. It was found that maximum ehancement of greening was achieved after 2 h of dark incubation following excision. Pretreatments with red light effected an additive rise in chlorophyll level in subsequent white light after a dark incubation, suggesting that the effects of excision and phytochrome on greening act independently. Etiolated seedlings were variously dissected before greening and it was found that enhancement occurred only when cotyledons were excised at the level of the hypocotyl hook or above it. Similar results were obtained when the dissected plants were pre-treated with red light.     

Intensified controlled fish growth in tanks implementing a multipurpose flow device

Fish biomass (Tilapia sp.) were raised at high stocking density in 1-m(3) tanks containing 450 L of water. The water was changed continously by means of a jet flow regulator. The jet flow regulator maintained adequate dissolved oxygen (DO) and a low ammonia level, while the suspended solids were discarded. In such a system, an annual yield of above 15 kg/m(3) can be expected. The application of the jet flow regulator in aquaculture is discussed.     

Purification of two muscle enzymes by chromatography on immobilized ferric ions

Two enzymes, glycogen phosphorylase and lactate dehydrogenase, were purified simultaneously in a single step. Ferric ions immobilized on a chelating gel were used as the adsorbent. Adsorption and desorption steps were accomplished by changes in buffer composition. The recoveries were better than 80% and the capacities were about 5 mg of protein per milliliter of adsorbent. The procedure worked well both on a small and on a preparative scale. The homogeneity of the purified enzymes was checked by FPLC.     

An Ustilago maydis Mutant Partially Blocked in P45014DM Activity Is Hypersensitive to Azole Fungicides

An Ustilago maydis ergosterol biosynthesis mutant (A14) which is partially blocked in sterol 14alpha-demethylase (P45014DM) activity is described. This mutant accumulated the abnormal 14alpha-methyl sterols, eburicol, 14alpha-methylfecosterol, and obtusifoliol, along with significant amounts of ergosterol. Although the A14 mutant grew nearly as well as the wild type, it was impaired in cell extension growth, which indicated a dysfunction in apical cell wall synthesis. The mutant was also found to be hypersensitive to the azole fungicides penconazole and tebuconazole.     

Passive electrical properties of Halobacterium species

The electrical conductivity of suspensions of two species of Halobacterium was measured at low A. C. frequency. The results obtained fromHalobacterium halobium suspensions show that the bacteria act as non-conducting particles. In contrast, the cells of a Halobacterium obtained from the Dead Sea (Halobacterium marismortui) had an apparently high conductivity which can be explained partly in terms of the cell-membrane being pierced by pores through which ions can move freely and partly in terms of highly concentrated cell ions, all of which are mobile.     

Purification of insect vitellogenin and vitellin by gel-immobilized ferric chelate.

Vitellogenin and vitellin of Manduca sexta and some other insect species were purified by immobilized metal ion affinity chromatography. Ferric ion was chosen as the immobilized metal ion. Agarose-bound carboxymethylpicolylamine was used as the chelating adsorbent for the ferric ion. Vitellogenin and vitellin, both phosphorylated lipoproteins, were shown to bind specifically to the iron. The general applicability of immobilized ferric ion affinity chromatography for the purification of insect vitellogenin and vitellin is suggested.     

Immobilization of enzymes based on hydrophobic interaction. III. Adsorbent substituent density and its impact on the immobilization of β-amylase

Hexyl-groups have been introduced into crosslinked Sepharose 6B, yielding gels with degrees of substitution which range from 0.02 to 0.70 mol hexyl-side chain per mole galactose residue. The gels were exposed to β-amylase in solution, and the resulting adsorbates indicated a monotonic increase in adsorption capacity with an increasing hexyl-content. Adsorbate activity, by contrast, displayed a maximum for a carrier gel with a hexyl–galactose ratio of 0.51. Adsorbates based on gels with different hexyl-content were used in column reactors for continuous maltose production from a soluble starch substrate.