W J Kopachik

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We compared the proteins synthesized and accumulated by Dictyostelium discoideum amoebae in response to the morphogenetic factor termed differentiation-inducing factor (DIF) to assess the proposed ability of DIF to regulate the choice of differentiation pathway. When amoebae of a mutant strain with low endogenous DIF levels were given DIF, they dramatically(More)
DIF is an endogenous extracellular signal that may control differentiation of D. discoideum cells. It is a dialyzable, lipid-like factor that induces stalk cell formation among isolated amebae incubated in vitro with cAMP. To examine the consequences of DIF deprivation, we have isolated several mutant strains that are impaired in DIF accumulation, and whose(More)
Hepatocyte nuclear factor-3alpha (HNF-3alpha), a member of the hepatocyte-forkhead-homolog family of transcription factors, regulates gene expression in the endoderm-derived liver and lung. To determine if HNF-3alpha might also play a role in endodermal derivatives of the urogenital sinus, the expression of HNF-3alpha in male accessory sex organs was(More)
The pathogenic LEE strain of Naegleria fowleri isolated from human or mouse brain loses pathogenicity when cultured axenically in a nutrient broth. To identify genes differentially expressed in highly virulent versus weakly virulent amoebae, a cDNA library was constructed by using mRNA from amoebae recovered from a mouse brain. Two cDNA clones were isolated(More)
Protein synthesis patterns of the low-virulence Naegleria fowleri LEE strain from axenic culture, the same strain after mouse brain passage to increase virulence, and the same strain after growth on bacteria were studied. Comparisons of accumulated proteins, in vivo-synthesized proteins, and in vitro-synthesized proteins translated from poly(A)+ mRNA were(More)
The simplified "All In One Tube" protocol for constructing a cDNA library combines the advantages of the "Classic method" and the Okayama-Berg method while overcoming some of their drawbacks. In this method, adding adapters, linkers or enzyme digestion steps are no longer necessary after cDNA synthesis, thus making it quicker and especially useful when(More)
The developmental stage at which Dictyostelium discoideum strain v12/M2 cells was inhibited in resuming cell division was monitored by a Coulter counter. Neither vegetative nor pre-aggregating v12/M2 amoebae used as inocula in liquid growth cultures exhibited a delay in recommencing cell division. Inocula prepared from aggregates were delayed for 3 h before(More)
Few eukaryotic genes are expressed only during cell growth and division. We found that the slime mold Dictyostelium discoideum is unusual in that it expresses many genes only during proliferation. Thirty-two percent (304/950) of the sequences in a cDNA library made from vegetative mRNA were homologous to RNAs that are present at high levels during growth(More)
We cloned and sequenced an intronless actin gene from the amoebo-flagellate Naegleria fowleri, LEE strain, an opportunistic pathogen of man. Codon usage and third-position-codon nucleotide frequency were significantly different from Acanthamoeba, another amoeba genus which also includes opportunistic pathogens of man. Between the two amoebae, actin peptide(More)
Protein synthesis by Polyspondylium violaceum in response to the chemoattractant glorin was analyzed by two-dimensional gel electrophoresis to determine if glorin can affect gene expression. When cells developing in a shaking suspension culture were given glorin, five proteins exhibited significantly increased and three proteins exhibited decreased(More)