Intracellular sites of the synthesis of sweet potato mitochondrial F1ATPase subunits

Summary Five subunits (-, -, -, - and -subunits) of the six -and -subunits) in the F₁ portion (F₁ATPase) of sweet potato (Ipomoea batatas) mitochondrial adenosine triphosphatase were isolated by an electrophoretic method. The - and -subunits were not distinguishable immunologically but showed completely different tryptic peptide maps, indicating that they were different molecular species. In vitro protein synthesis with isolated sweet potato root mitochondria produced only the -subunit when analyzed with anti-sweet potato F₁ATPase antibody reacting with all the subunits except the -subunit. Sweet potato root poly(A)⁺RNA directed the synthesis of six polypeptides which were immunoprecipitated by the antibody: two of them immunologically related to the -subunit and the others to the - and -subunits. We conclude that the -subunit of the F₁ATPase is synthesized only in the mitochondria and the -, - and -subunits are in the cytoplasm.     

Sialidase of swine influenza A viruses: variation of the recognition specificities for sialyl linkages and for the molecular species of sialic acid with the year of isolation

The sialidase of swine influenza A viruses of N1 and N2 subtypes, isolated from 1930 to 1992, was studied for substrate specificity with ganglio-series, lacto-series type II and GM3 gangliosides containing Neu5Ac2-3Gal, Neu5Gc2-3Gal and Neu5Ac2-6Gal linkages. All viral sialidases tested showed that the activity for hydrolysing substrates with Neu5Ac2-3Gal was higher than the activities with Neu5Gc2-3Gal and Neu5Ac2-6Gal linkages. When GM1b, GM3 and sialylparagloboside were used as substrates, the earliest strain (A/Wisconsin/15/30 H1N1, isolated in 1930) showed the activity ratio of Neu5Ac2-6Gal to Neu5Ac2-3Gal to be 0.13:0.2, and the ratio Neu5Gc2-3Gal/Neu5Ac2-3Gal to be 0.19:0.37, while those strains isolated from 1978 to 1992 exhibited ratios of 0.29:0.58 for Neu5Ac2-6Gal/Neu5Ac2-3Gal and 0.51:0.76 for Neu5Gc2-3Gal/Neu5Ac2-3Gal. The above results indicate that the substrate specificities of sialidases from swine influenza A viruses towards sialyl linkages and the molecular species of sialic acid are related to the year of isolation, i.e. strains isolated after 1978 exhibited higher activity towards Neu5Ac2-6Gal and Neu5Gc2-3Gal linkages when compared with strains isolated in an earlier year, 1930.Abbreviation Neu5Ac 5-N-acetylneuraminic acid - Neu5Gc 5-N-glycolyneuraminic acid - Gal d-galactose - Glc d-glucose - Cer Ceramide - II³(Neu5Ac)Lac Neu5Ac2-3Gal1-4Glc - GM3(Neu5Ac2-3Gal) Neu5Ac2-3Gal1-4Glc1-Cer - GM3(Neu5Gc2-3Gal) Neu5Gc2-3Gal1-4Glc1-Cer - GM1b(Neu5Ac2-3Gal) Neu5Ac2-3Gal1-3GalNac1-4Gal1-4Glc1-Cer - GMlb(Neu5Gc2-3Gal) Neu5Gc2-3Gal1-3GalNAc1-4Gal1-4Glc1-Cer - IV³(Neu5Ac)nLc4Cer Neu5Ac2-3Gal1-3GlcNAc1-4Gal1-4Glc1-Cer - IV³(Neu5Gc)nLc4Cer Neu5Gc2-3Gal1-3GlcNAc1-4Gal1-4Glc1-Cer - IV⁶(Neu5Ac)nLc4Cer Neu5Ac2-6Gal1-3GlcNAc1-4Gal1-4Glc1-Cer - TDC taurodeoxycholate.     

Multiple shoot regeneration from root organ cultures of Populus alba x P. grandidentata

Excised roots of various ages from Crandon and Hansen clones of Populus alba x P. grandidentata were tested for their regeneration capacity. Sixty-day-old excised roots that contained root tips were found to be most suitable. The highest number of shoots (an average of 111 shoots/root segment with Crandon and 98 with Hansen) was obtained by adding 22M and 14M zeatin to the medium, respectively. The two clones of hybrid poplar responded similarly to growth regulator treatments; however, the number of shoots produced was greater from the root organs derived from Crandon clones. Regenerated shoots were rooted in basal Woody Plant Medium without any growth regulators. Successful transplantation into soil and growth was achieved with all plants.     

Donor tissue and culture condition effects on mesophyll protoplasts of Medicago sativa

Mesophyll protoplasts were produced from clones of two cultivars of Medicago sativa, Rangelander and Regen S. Protoplasts from the Regen S clone generally gave rise to calli while those from the Rangelander clone would undergo direct embryogenesis. Effects of plant growth conditions, donor tissue pretreatment and protoplast culture conditions on mesophyll protoplast production and subsequent development patterns were investigated. The major factor determining whether or not mesophyll protoplasts would be produced from either of the clones was the pretreatment in water of shoots excised from the donor plants. Pretreatment in water containing growth regulators did not alter protoplast production or development in the Regen S clone. Pretreatment of the Rangelander clone shoots with abscisic acid or naphthaleneacetic acid was slightly beneficial to embryo production while pretreatment with benzylaminopurine was detrimental. Altered leaf morphology induced by growth condition changes did not affect mesophyll protoplast production or subsequent development patterns when shoots were pretreated in water. Culture of protoplasts in liquid droplets or solid agar medium increased low density protoplast survival and subsequent embryo production in the Rangelander clone.     

Lysine Dendrimers and Their Starburst Polymer Derivatives: Possible Application for DNA Compaction and in vitro Delivery of Genetic Constructs

We attempted to find some compounds for the effective delivery of gene constructs into cells and obtained two trispherical dendrimers on the basis of lysine, (Lys)₈-(,-Lys)₄-(,-Lys)₂-(,-Lys)-Ala-NH₂ (D1) and ((Lys)₈-(,-Lys)₄-(,-Lys)₂-,-Lys)-Ala-[Lys(Plm)]₂-Ala-NH₂ (D2), as well as the starburst polymeric derivatives of D1, (pVIm) ₈ -D1 and (pLys) _n -D1, containing poly(N-vinylimidazole) and polylysine chains single-point bound to the dendrimer amino groups. The conditions of dendrimer–plasmid DNA complex formation were studied. The intracellular localization of these complexes and the expression of gene constructs delivered with their help were analyzed in transfection experiments on the HeLa cell cultures of human epithelial carcinoma and on mouse C2C12 myoblasts. It was found that the chemical structure of dendrimer D1 and its derivatives significantly affected the structure and properties of complex.     

Synthesis of Gal-β-(1→4)-GlcNAc-β-(1→6)-[Gal-β- (1→3)]-GalNAc-α-OBn oligosaccharides bearing O-methyl or O-sulfo groups at C-3 of the Gal residue: specific acceptors for Gal: 3-O-sulfotransferases

Our recent studies have revealed the existence of two distinct Gal: 3-O-sulfotransferases capable of acting on the C-3 position of galactose in a Core 2 branched structure, e.g., Gal14GlcNAc16(Gal13)GalNac1OBenzyl as acceptor to give 3-O-sulfoGal14GlcNAc13(Gal13)GalNAc1OB 20 and Gal14GlcNAc16(3-O-sulfoGal13)GalNAc1OB 23. We herein report the synthesis of these two compounds and also that of other modified analogs that are highly specific acceptors for the two sulfotransferases. Appropriately protected 1-thio-glycosides 7, 8, and 10 were employed as glycosyl donors for the synthesis of our target compounds.     

Crystal formation in cultures of fungi II

Summary The present study offers the picture of crystal formation in cultures of dermatophytes photographed in white light. Isometric and anisometric crystal forms are profusely depicted. Pranks and mimics of crystal forms are pointed out. Photomicrographic data are given.

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Zusammenfassung In der vorliegenden Untersuchung wird das Bild der Krystallbildung in Dermatophytenkulturen in weissem Licht dargestellt. Isometrische und anisometrische Krystallformen werden reichlich illustriert. Auf Streiche und Nachahmungen der Krystallformen wird hingewiesen. Photomikrographische Daten sind gegeben.

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Résumé La présente étude offre le tableau des formations des crystaux des dermatophytes photographiées en lumière blanche. Des formes isométriques et anisométriques des crystaux ont été illustrées abondamment. Des coups et des mimiques des crystaux sont présentés. Les données photomicrographiques ont été élucidées.

     

Quercetin suppresses proinflammatory cytokines production through MAP kinases and NF-κB pathway in lipopolysaccharide-stimulated macrophage

Quercetin is a flavonoid molecule ubiquitous in nature and functions as an anti-oxidant and anti-inflammatory agent with little toxicity in vivo and in vitro. Dose- and time-dependent effect of quercetin has been investigated on proinflammatory cytokine expression and NO production, focusing on its effects on the MAP kinases and the NF-B signal transduction pathways in LPS-stimulated RAW 264.7 cells by using RT-PCR and immunoblotting. Quercetin strongly reduced activation of phosphorylated ERK kinase and p38 MAP kinase but not JNK MAP kinase by LPS treatment. In addition, quercetin treatment inhibited NF-B activation through stabilization of the NF-B/IB complex and IB degradation and proinflammatory cytokines and NO/iNOS expression. Quercetin may exert its anti-inflammatory and immunomodulatory properties in the effect molecules such as proinflammatory cytokines and NO/iNOS by suppressing the activation of ERK and p38 MAP kinase, and NF-B/IB signal transduction pathways.     

ααααanti-3.7 type II: a new α-globin gene rearrangement suggesting that the α-globin gene duplication could be caused by intrachromosomal recombination

Summary We report here a new human -globin gene rearrangement carrying the two normal, 2 and 1, and two hybrid, 1/2, globin genes in the order 5-2-1/2-1/2-1-3. Both the hybrid genes, subtyped with ApaI and RsaI restriction enzymes, were found to be of the uncommon anti 3.7 type II. The hybrid genes were expressed at the biosynthetic level and their interaction with the -thalassaemia IVS 1 nt 1 GA mutation caused thalassaemia intermedia. We also report a case of an -globin gene rearrangement in the twin of one of the -globin gene carriers; the duplicated gene was of the anti 4.2 type and was associated with the absence of RsaI polymorphism. The singular finding of an -anti 3.7 cluster with two identical rare hybrid genes suggests that the reciprocal unequal recombination causing the -globin gene rearrangements could be of the intra-chromosomal rather than the interchromosomal type.     

Dynamics and potential impact of ‘generalist’ phytoseiids in agroecosystems and possibilities for establishment of exotic species

Generalists, i.e. those species which consume a wide variety of foods, including some of plant origin such as pollen, are the dominant members of the phytoseiid mite fauna in some perennial crops. Biological attributes commonly evident in generalist in contrast to specialist phytoseiids include a lower reproductive potential on mite prey, close association with certain plant species, population increases in the absence of mite prey, and intraplant distribution unrelated to that of spider mites. Some studies are reviewed that suggest the ability of certain generalist phytoseiids to maintain tetranychid populations at low densities. Possible biological factors influencing the establishment of exotic generalist phytoseiids are considered. Some of the attributes usually considered important in effective phytoseiid predators may be of minor importance in more stable situations at low population densities.     

Adoptions expérimentales de larves entre des fourmis de genres différents (II):Myrmica laevinodis Nylander etAnergates atratulus Schenck

Résumé Nous avons fait élever des larves d'Anergates atratulus par des ouvrières deMyrmica laevinodis à 22°C. Pour y parvenir, il n'est pas utile de faire hivernerensemble les larves d'Anergates et les ouvrières deMyrmica. La présence de larves autochtones n'empêche pas lesMyrmica d'élever des larves d'Anergates. Dans toutes les expériences lesMyrmica ont été soumises au fridavant de recevoir des larves d'Anergates. Aucune reine deMyrmica n'a été utilisée dans ces expériences.Sur les 64 larves d'Anergates que nous avons utilisées, 38 se sont transformées en imagos. C'est au début de l'adoption et au moment des métamorphoses que périrent la plupart des 26Anergates perdus. Les femelles vécurent en général 2 ou 3 jours et cherchèrent très tôt à quitter le nid natal. Les mâles vécurent 2 à 3 semaines.

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Summary Larvae ofAnergates atratulus were experimentally reared by workers ofMyrmica laevinodis, at 22°C. An overwintering of both larvae ofAnergates and workers ofMyrmica is not necessary for the success of that experiment. The presence of larvae ofMyrmica does not keep theMyrmica from rearing larvae ofAnergates. The workers ofMyrmica have been cooled, in all the experiments, before receiving larvae ofAnergates. No queen ofMyrmica have been used in that experiments.38 of the 64 larvae ofAnergates used became imagos. Most of the 26 lostAnergates died at the beginning of the adoption and during the metamorphosis. The females lived generally 2 or 3 days and tried, very early, to leave their native nest. The males lived 2 or 3 weeks.

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Anergates atratulus Myrmica laevinodis, 22 . bmecme Anergates Myrmica. Myrmica Anergates. Myrmica Anergates. Myrmica . 64 Anergates , 38 . 26 Anergates 2 3 . 2 3 .

     

Photoreactivation of the UV light effects on growth of Scots pine (Pinus sylvestris L.) seedlings

Summary Ultraviolet-B light (UV-B) and ultraviolet-A light (UV-A) at higher doses exert a strong inhibitory (toxic) effect on axis growth in Scots pine (Pinus sylvestris L.) seedlings. This effect is unrelated to control of growth rate by phytochrome. Rather, after a toxic UV dose growth of the pine seedling no longer responded to phytochrome. Both, the effect of UV-B as well as the inhibiting effect of UV-A could be photoreactivated by blue light (B). The action of UV-A was 2 fold: (i) it exerted a toxic effect which could be photoreactivated by B, and (ii) applied after UV-B it photoreactivated to some extent the toxic UV-B effect. Obviously, the UV-A range causes a toxic effect, and at the same time is capable of photoreactivating the toxic UV effect. At higher doses the toxic effect prevails.     

On the role of the invariant glutamine at position 54 in the human choriogonadotropin β subunit

The twelve Cys and eight of the non-Cys residues are invariant in the glycoprotein hormone subunits from a variety of mammalian species. -Gin-54 of human lutropin (hLH) and choriogonadotropin (hCG) is one of these invariant amino acid residues. A single AG mutation in the LH gene of a patient presenting with hypogonadism resulted in the replacement of Gin-54 with Arg [1]. The authors also reported that an expressed mutant of hLH, with Arg replacing Gin-54, associated with the subunit, but there was no demonstrable binding of the mutant hormone to receptor. We have replaced Gin-54 in hCG with Glu and with Lys using site-directed mutagenesis. The expression plasmids pRSV-hCG (wild-type and mutants) were transiently transfected into CHO cells containing a stably integrated gene for bovine , and the media were analyzed for holoproteins, which were characterizedin vitro using competitive binding and steroidogenic assays with MA-10 cells. hCG(Glu-54) bound to almost as well as hCG wild-type, and the resulting heterodimer competed with [¹²⁵l]hCG binding to the LH/CG receptor and stimulated progesterone production to the same extent as the wild-type control. However, the apparent potencies, as judged by ED₅₀s, were less than those of the wild-type control, the effect being more pronounced in binding than in steroidogenesis. In contrast, hCG(Lys-54) associated very poorly with . Our results suggest that while Gin-54 in hCG participates in receptor binding, its major function appears to involve binding. Such dual functionality leads to interesting models for holoprotein formation and receptor binding.     

Inheritance of resistance to potato viruses Y and A in progeny obtained from potato cultivars containing gene Ry:evidence for a new gene for extreme resistance to PVA

Extreme resistance in cultivated potato (Solanum tuberosum) to potato viruses Y and A (PVY and PVA) conditioned by the presence of Ry genes introduced from Solanum stoloniferum was described by Cockerham (1970). Cockerham detailed a number of genes which controlled a variety of reactions, including extreme resistance to both viruses (i.e. little or no visible reaction of plants and no viral replication following graft and manual inoculation) controlled by gene Ry _sto. In the present study, cvs Pirola and Barbara, which contain a Ry gene, were found to have extreme resistance to PVY isolates from the ordinary (PVY°), veinal necrosis (PVY^N) and potato tuber necrotic ringspot (PVY^NTN) subgroups, and PVA. The inheritance of this phenotype was examined in seedling progenies obtained by crossing Barbara and Pirola with susceptible cultivars. Segregation data for resistance to PVY and PVA in a progeny involving cv Pirola best fitted a genetical model of one gene controlling extreme resistance to both PVY and PVA, although the possibility that there are two genes, each controlling resistance to one virus but closely linked, cannot be excluded. Segregation data from progenies involving cv Barbara best fitted a genetical model in which there are two independent genes, one controlling extreme resistance to PVA and PVY and a second gene controlling extreme resistance to PVA but not to PVY. This previously unrecognised gene conferring extreme resistance to PVA only, should be given the notation Ra in keeping with nomenclature used for other resistance genes.     

Primate hemoglobins: Some sequences and some proposals concerning the character of evolution and mutation

During a multipurpose survey we examined electrophoretic mobilities of major (A, i.e., ₂₂) and minor (A₂, i.e., ₂₂) adult hemoglobins from populations of nine primate genera representing a total of 440 New World monkeys and apes. Sequences of hemoglobin chains were inferred from differences in amino acid composition between homologous tryptic peptides supplemented by detailed placement of more than 270 residues. Beta sequences were thus analyzed in five genera (Aotus, Ateles, Hylobates, Saimiri, and Saguinus) and sequences in seven (foregoing plus Gorilla and Pan). In most genera, sequences from several individuals, often from several species, were delineated. Fifteen kinds of intraspecies mutants were detected; 10 of these were precisely characterized. Five of the 15 mutants form electrophoretically detected genetic polymorphisms of ; none such occur in . Six electrophoretically detected mutants, four in and two in , are uncommon. One of these represents the complete absence of minor component. Three kinds of variants, two in and one in , are electrophoretically neutral and chance findings during sequence analysis of the equivalent of 38 allele products. Two of the neutral variants are not especially common; one may have polymorphic frequency. Several general conclusions stem from these and supplementary findings. First, comparisons of sequences suggest that and genes in all primates either arose from a single event in a common ancestor or from two approximately coincident events. Either assumption allows reconstruction of a reasonably accurate archetype sequence that is effectively common to all descendants. Second, there is a pancellular quantitative disproportion between major and minor hemoglobins ranging from 16:1 to 220:1 in species studied. Delta is consequently presumed to be functionally and adaptively less vital than . When these premises are adopted, is expected to be relatively invisible to natural selection, and, where darwinism is the principal arbiter of evolution and polymorphism, is expected to show fewer fixed changes and fewer genetic polymorphisms than . The opposite is observed. Delta exhibits as many or more changes from archetype than . This finding and the comparative abundance of polymorphism are attributed to nonadaptive factors which are thus considered the source of much evolutionary change. Third, particular sequence positions in various species are the site of recurrent mutations in both and . One such area is occupied by the majority of genetic polymorphisms found in man and other primates. The overall distribution of mutations arising in evolution is remarkably nonrandom in , , and a pool of both. These results are quite unlike most other observations in higher organisms. The sources of such nonrandomness are either selection and/or differential mutability. We rely on our prior assumption of relative selective invisibility for and, in part, ascribe the nonrandom distribution of changes to microzones of enhanced mutability. Fourth, the six uncommon electrophoretically detected mutants provide an estimate of heterozygosity (1/73) at hemoglobin loci that is tenfold greater than observed in man. Fifth, the unprecedented chance detection of three kinds of electrophoretically neutral intraspecies mutants among the equivalent of 38 characterized allele products suggests that neutral changes are as common as electrostatically active ones and at least tenfold more common than expected in extrapolation from human variant surveys. Sixth, analyses from three kinds of gibbon (Hylobates) hemoglobin suggest that one of these is a potentially unchanged relict of the ancient archetype and, further, indicate a degree of homozygous diversity within a species that nearly equals the difference between gibbon and man.This investigation received support from grants to S.H.B., HD-02508-04 and K3-GM-6308-03, from the National Institutes of Health.     

Die optischen Übertragungseigenschaften der Komplexaugen von Drosophila

Summary The transfer properties of the optical system in the arthropod compound eye are determined by the interommatidial angle , influencing the resolving power, and by the width of the visual fields of single ommatidia , influencing the response at high spatial frequencies of brightness distributions in the object space. The energy transfer/ receptor is proportional to ( )² and decreases with in-inreasing approximation of the perfect-imaging condition: gD 0; 0. However, a value > 0 has to be maintained in order to overcome the threshold of nervous excitation at a certain minimum-brightness level. Theoretical treatment yields /=0.62 to 0.88 as the corresponding optimum-imaging relation. The actual ratio can be derived from measurements of the optomotor reactions to the movement of periodic brightness patterns. The approximate value 0.76 is obtained from the fruitfly Drosophila with normal and mutant eye pigmentation. As a result, the parameters of this imaging system are found to be established in a way that enables optimum performance at sufficient illumination. An dieser Stelle möchte ich Dr. W. Reichardt für sein eingehendes Interesse und manche anregende Diskussion über die Sehvorgänge im Komplexauge meinen Dank sagen. Dr. K. Kirschfeld verdanke ich ebenfalls wertvolle Hinweise. Herrn E. Freiberg bin ich für die Anfertigung der Abbildungen sehr verbunden.     

Different ζ globin gene deletions among Black Americans

Summary Four types of chromosomes with a deletion between the human embryonic and globin genes were identified among 2.8% of 321 Black Americans from Georgia. Two deletions of approximately 11 kb which differed by about 300 bp occurred on chromosomes with or without a polymorphic Xba I site 5 to the globin gene [(X⁺) or (X^-)]. The deletions are identifiable in Xba I digests of genomic DNA using an or a globin gene probe which yield fragments of 23 kb from (X⁺)–^* chromosomes or 27 kb from (X^–)–^* chromosomes. Digestion with other enzymes and probing with both and probes gave fragments typical of the two globin gene deletions previously identified in Polynesians. Among Black Americans, these globin gene deletions have been found in combination with globin gene deletions in trans but not in cis. Homozygotes have not been found. Hematologic data on carriers of the globin gene deletions in association with Hb AS, SS, and SC suggest that these deletions have no effect on the function of the adult globin genes.     

Screening of turfgrass species and cultivars for NaCl tolerance

Summary Information regarding the relative levels of salt tolerance between cultivars of Kentucky bluegrass (Poa pratensis L.) is lacking. The objectives of this study were to 1) develop a simple, quick and sensitive method of screening turfgrass species for NaCl tolerance and 2) to compare the relative salt tolerance of five cultivars of Kentucky bluegrass (Ram I, Adelphi, Baron, Bensun, and Nassau) to other known salt tolerant turfgrass species such as alkalaigrass (Puccinellia distans (L.) Parl. cv. Fults) and two cultivars of red fescue (Festuca rubra L. Dawson, and Checker).Alkalaigrass and both cultivars of red fescue retained a high level of salt tolerance compared to the Kentucky bluegrass cultivars. Significant variability in salt tolerance was apparent among the Kentucky bluegrass cultivars with Adelphi and Ram I exhibiting the best overall tolerance.     

Effect of nucleosides and nucleotides and the relationship between cellular adenosine 3′∶5′-cyclic monophosphate (cyclic AMP) and germ tube formation in Candida albicans

A yeast-mycelium (Y-M) transition in Candida albicans was induced by exogenous yeast extract, adenosine, adenosine 5-monophosphate (AMP), adenosine 5-diphosphate (ADP), adenosine 35 cyclic monophosphate (cAMP) and its analogue N⁶, O²-dibutyryl adenosine 35-cyclic monophosphate (dbcAMP) in defined liquid medium at 25°C. Adenosine 5-triphosphate (ATP) was found to delay germ tube formation in yeast cells, whereas the cAMP phosphodiesterase inhibitors, theophylline and caffeine, induced a Y-M transition. Intracellular and extracellular cyclic AMP levels increased during the yeast-mycelium transition and maximum levels of intracellular cyclic AMP coincided with maximum germ tube formation. Of the many inducers and inhibitors of germ tube and mycelium formation in C. albicans tested, including incubation at 37°C or in the presence of 1.5mM CaCl₂, the calmodulin inhibitor calmidazolium (R24571) added together with CaCl₂ induced the highest intra- and extracellular cyclic AMP levels. These results confirm the involvement of cyclic AMP in the yeast-mycelium transition of C. albicans.     

Alpha-factor leader sequence-directed transport of Escherichia coli beta-galactosidase in the secretory pathway of Saccharomyces cerevisiae

Summary The constuction of two fused genes is described. One involves the in-frame fusion of the yeast prepro--factor coding sequence, and the Escherichia coli lac Z gene. The second gene fusion utilizes a 103 bp yeast invertase NH₂-terminal coding sequence at the fusion junction of the hybrid gene described above. The gene fusions, under the control of the -factor promoter, expressed active -galactosidase in haploid yeast cells. The activity could be regulated in a temperature-sensitive sir3 mutant. The incorporation of the invertase coding sequence at the MF1-lacZ fusion junction provided significantly higher levels of -galactosidase activity. A substantial quantity of the hybrid proteins generated from the gene fusions was primarily localized in the intracellular membranes of yeast cells, while a processed form could be secreted into the periplasm.A portion of this work appeared in Biotechnology Progress (Das and Shultz 1986) as proceedings of the symposium on Industrial Scale Protein Purification, held at the annual meeting of the Institute of Chemical Engineers in Miami Beach, Fla, USA on November 4, 1986