HH2A,an immortalized bovine mammary epithelial cell line,expresses the gene encoding mammary derived growth inhibitor (MDGI)

Summary We have established and partially characterized a spontaneously immortalized bovine mammary epithelial cell line, designated HH2a. The cells express the gene encoding for mammary derived growth inhibitor (MDGI) when grown on released collagen gels in the presence of lactogenic hormones. This is the first report of a cell line that expresses MDGI. Immunohistochemical studies showed that HH2a cells contain keratin intermediate filaments and desmosomes. When plated on confluent monolayer of live fibroblasts, HH2a cells extensively contacted with fibroblasts. When embedded in the collagen gels, they rearranged themselves to produce three-dimensional duct-like outgrowths extending into the matrix. The HH2a cell line should be useful in investigations of the roles of cell-cell and cell-extracellular interactions in regulation of breast epithelial cell proliferation, and of the hormonal regulation of MDGI gene expression.     

A novel human type I hair keratin gene: evidence for two keratin hHa3 isoforms

We present the nucleotide and amino acid sequence for a novel human type I hair keratin, which could be identified through its high sequence homology and strict carboxyterminal length identity as a human ortholog of the murine hair keratin mHa3. Our hHa3 sequence differs, however, from that of a previously described hHa3 hair keratin (published only as an amino acid sequence; [13]) in 24 amino acid positions, 8 of which occur in the middle of the carboxyterminal domain. PCR of genomic DNA from 25 normal human subjects using a primer pair derived from sequence segments located in the 3-region of our hHa3 clone that encode conserved amino acid sequences in both keratins, resulted in the amplification of two distinct products of 0.38 kbp and 1.0 kbp. DNA sequence analysis of the cloned PCR products allowed identification of the 0.38 kb sequence as that originating from Yuet al. [13] and the 1.0 kb sequence as that being derived from our data. The difference in fragment length was due to unique intron 6 sequences, indicating that these two keratin species are encoded by genes of their own. Moreover, extensive Southern blot analyses with DNA from 25 unrelated individuals of different races using a 3-noncoding sequence from our keratin and the intron 6 sequence of the keratin of Yuet al. [13], as hybridization probes showed that both keratin genes are present as single copy sequences occurring ubiquitously and without gross alterations in the human genome. Collectively, these data demonstrate that the human type I hair keratin described in this paper represents an isoform of the previously described hHa3 keratin. We propose that these hHa3 isoforms be named in chronological order of discovery hHa3-I and hHa3-II.     

The Culture Concept and the Mission of the Roman Catholic Church

This essay examines how the Roman Catholic Church uses a version of the concept of culture in its evangelizing mission. The field of Christian evangelization is not commonly studied by anthropologists, but it represents a situation parallel to that of international and political development, which has similarly been informed by the anthropological concept of culture but translates that concept into action in ways that are not always consonant with anthropological theory. The great size and international reach of the Roman Catholic Church commend it to our attention insofar as it draws on a version of the anthropological perspective in its dealings with people in a multicultural society.     

The spindle pole body of yeast

Microtubule organizing centers play an essential cellular role in nucleating microtubule assembly and establishing the microtubule array. The microtubule organizing center of yeast, the spindle pole body (SPB), shares many functions and properties with those other organisms. In recent years considerable new information has been generated concerning components associated with the SPB, and the mechanism by which it duplicates. This article reviews our current view of the cytology and molecular composition of the SPB of the budding yeast, Saccharomyces cerevisiae, and the fission yeast, Schizosaccharomyces pombe. Genetic studies in these organisms has revealed information about how the SPB duplicates and separates, and its roles during vegetative growth, mating and meiosis.     

A new species of Talauma (Magnoliaceae) from Bolivia

Talauma boliviana is described as new and illustrated. This species, first collected in 1989, is the only Magnoliaceae known from Bolivia. It seems to be most closely related toT. sambuensis of northwestern Colombia and eastern Panama.     

Spicebush [Lindera benzoin (L.) Blume var.benzoin,Lauraceae]: A tea,spice, and medicine

The essential oils of fresh leaves, twigs, and/or fruits of spicebush cultivated in Oregon (field distilled) and Delaware (laboratory distilled) are examined by GC/MS. The oil of leaves of spicebush is notably high in 6-methyl-5-hepten-2-one (1.94% in Oregon to 34.83 ± 9.69% in Delaware). β-caryophyllene (15.26% in Oregon to 48.44 ± 1.35% in Delaware), and/or (E)-nerolidol (10.20% in Oregon to 12.05 ± 2.02% in Delaware). The oil of the twigs of spicebush is notably high in 1,8-cineole (45.41 ± 0.35% in Delaware), while the oil of the fruits is notably high in a-phellandrene (64.62 ± 0.66% in Delaware) and β-phellandrene (11.23+0.17% in Delaware).     

The homologous operons for P1 and P7 plasmid partition are autoregulated from dissimilar operator sites

The plasmid-partition regions of the P1 and P7 plasmid prophages in Escherichia coli are homologues which each encode two partition proteins, ParA and ParB. The equivalent PI and P7 proteins are closely related. In each case, the proteins are encoded by an operon that is autoregulated by the ParA and ParB proteins in concert. This regulation is species-specific, as the P1 proteins are unable to repress the P7 par operon and vice versa. The homologous ParA proteins are primarily responsible for repression and bind to regions that overlap the operon promoter in both cases. The DNA-binding domain of the P7 auto-repressor lies in the amino-terminal end of the P7 ParA protein. This region includes a helix-turn-helix motif that has a clear counterpart in the P1 ParA sequence. However, despite the common regulatory mechanism and the similarity of the proteins involved in repression, the promoter-operator sequences of these two operons are very different in sequence and organization. The operator is located downstream of the promoter in P1 and upstream of it in P7, and the two regions show little, if any, homology. How these differences may have arisen from a common ancestral form is discussed.     

Characterisation of a 5-bp deletion in exon 4 of the factor VIII gene: concordance with slipped-mispairing at DNA replication

In an attempt to characterize disease producing mutations in the factor VIII gene we screened exons 4, 7, 8, 11, 12 and 16 by PCR-SSCP (polymerase chain reactionsingle strand conformation polymorphism), in 12 randomly selected haemophilia A patients. These exons were chosen because they have been reported to harbour a disproportionately high number of mutations relative to their size. Using this strategy we detected a frame-shifting 5-bp deletion (TACCT, involving nucleotides 519–523), which is predicted to result in a severely truncated factor VIII polypeptide, terminating approximately midway through the conserved A1 domain and resulting in the observed severe phenotype. We also showed that the sequence in the vicinity of the observed deletion is concordant with the modified slipped-mispairing at DNA replication model of Krawczak and Cooper.     

Comparative development of Cryptosporidium parvum (Apicomplexa) in 11 continuous host cell lines

Abstract Using standardized media, incubation, and parasite inoculating procedures, we compared development of Crytosporidium parvum between Madin-Darby bovine kidney (MDBK) cells and 10 additional host cell lines available through the American Type Culture Collection. Parasite development was assessed by counting parasite numbers atop monlayers in 25 random oil fields 68 h post-infection using Nomarski interference-contrast optics. Results revealed that the human ileocecal adenocarcinoma (HCT-8) cell line supported nearly twice the number of parasite developmental stages than MDBK cells or any of the other host cell types.