Estrogen-androgen antagonism in the regulation of epidermal growth factor in mouse submandibular salivary gland and kidneys

To eludicate hormonal regulation of epidermal growth factor (EGF) concentration we studied the effects in adult female mice of ovariectomy and postovariectomy treatments with testosterone plus estradiol on the EGF concentrations in submandibular salivary gland (SMG), plasma, kidneys and urine. In the tissues, we also studied the location of EGF immunohistochemically and measured EGF mRNA. After ovariectomy, SMG EGF first decreased to one third of preovariectomy level. After postovariectomy day 10 it started to increase and reached by day 80 3.5-fold the preovariectomy level. Simultaneously, EGF mRNA increased. Testosterone treatment further strongly augmented the levels of both EGF mRNA and EGF. A small dose of estradiol counteracted slightly the mRNA effect of testosterone. After ovariectomy plasma EGF first increased 1.3-fold by day 10, then returned to the initial levels, and rose again 1.6-fold by day 80. Testosterone treatment induced a further 1.5-fold increase. Estradiol did not counteract this effect. Kidney EGF decreased 15% by postovariectomy day 20. This was preceded by a decrease in EGF mRNA from day 10 onwards. The EGF concentration recovered during the 80 days, but the EGF mRNA level stayed low. Testosterone treatment further reduced the levels of both EGF mRNA and EGF. This effect was counteracted by estradiol. Urine EGF increased after ovariectomy to a peak (1.7-fold) by day 40. It then returned to the preovariectomy levels by day 80. Testosterone treatment increased urinary EGF 1.9-fold; concomitant estradiol had no effect.     

Fc receptor isoforms exhibit distinct abilities for coated pit localization as a result of cytoplasmic domain heterogeneity

Mouse macrophages and lymphocytes express two distinct isoforms of a single class of Fc receptor for IgG. The macrophage isoform (FcRII-B2) is identical to the lymphocyte isoform (FcRII-B1) except for an inframe insertion in the cytoplasmic tail of FcRII-B1 that increases its length from 47 to 94 amino acids. To determine the functional significance of this cytoplasmic domain variation, presumably the result of alternative mRNA splicing, we expressed both isoforms in receptor-negative fibroblasts. While FcRII-B2 mediated the efficient ligand internalization and delivery to lysosomes, endocytosis via FcRII-B1--and via a tailminus mutant--was relatively inefficient. This difference reflected the inability of FcRII-B1 (and the tailminus mutant) to accumulate in clathrin-coated pits. Thus, the FcRII-B2 cytoplasmic tail contains a domain needed for accumulation in coated pits, and this domain is disrupted by the 47 amino acid insertion in FcRII-B1.     

Serum selenium concentration related to myocardial infarction and fatty acid content of serum lipids.

A longitudinal case-control study of 33 patients with one or more risk factors for coronary heart disease and 64 controls showed that the serum selenium concentration (range 0.63-1.33 mumol/l (50-105 micrograms/l] was not associated with development of clinical manifestations of coronary heart disease during a follow up of five to seven years. The content of polyunsaturated fatty acids, especially eicosapentaenoic acid, in serum cholesterol esters and phospholipids was positively correlated with selenium concentration. As a low content of polyunsaturated fatty acids in serum lipids was an independent risk factor for coronary heart disease in these subjects it may be hypothesised that the high coronary risk in subjects with a very low serum selenium concentration (less than 0.57 mumol/l (less than 45 micrograms/l] might be due not to selenium deficiency but to the coexisting low concentrations of polyunsaturated fatty acids in serum.     

Detection and typing of Campylobacter jejuni and Campylobacter coli and analysis of indicator organisms in three waterborne outbreaks in Finland

Waterborne outbreaks associated with contamination of drinking water by Campylobacter jejuni are rather common in the Nordic countries Sweden, Norway, and Finland, where in sparsely populated districts groundwater is commonly used without disinfection. Campylobacters, Escherichia coli, or other coliforms have rarely been detected in potential sources. We studied three waterborne outbreaks in Finland caused by C. jejuni and used sample volumes of 4,000 to 20,000 ml for analysis of campylobacters and sample volumes of 1 to 5,000 ml for analysis of coliforms and E. coli, depending on the sampling site. Multiple samples obtained from possible sources (water distribution systems and environmental water sources) and the use of large sample volumes (several liters) increased the chance of detecting the pathogen C. jejuni in water. Filtration of a large volume (1,000 to 2,000 ml) also increased the rate of detection of coliforms and E. coli. To confirm the association between drinking water contamination and illness, a combination of Penner serotyping and pulsed-field gel electrophoresis (digestion with SmaI and KpnI) was found to be useful. This combination reliably verified similarity or dissimilarity of C. jejuni isolates from patient samples, from drinking water, and from other environmental sources, thus confirming the likely reservoir of an outbreak.     

Modified ribosome profiling reveals high abundance of ribosome protected mRNA fragments derived from 3′ untranslated regions

Ribosome profiling identifies ribosome positions on translated mRNAs. A prominent feature of published datasets is the near complete absence of ribosomes in 3′ untranslated regions (3′UTR) although substantial ribosome density can be observed on non-coding RNAs. Here we perform ribosome profiling in cultured Drosophila and human cells and show that different features of translation are revealed depending on the nuclease and the digestion conditions used. Most importantly, we observe high abundance of ribosome protected fragments in 3′UTRs of thousands of genes without manipulation of translation termination. Affinity purification of ribosomes indicates that the 3′UTR reads originate from ribosome protected fragments. Association of ribosomes with the 3′UTR may be due to ribosome migration through the stop codon or 3′UTR mRNA binding to ribosomes on the coding sequence. This association depends primarily on the relative length of the 3′UTR and may be related to translational regulation or ribosome recycling, for which the efficiency is known to inversely correlate with 3′UTR length. Together our results indicate that ribosome profiling is highly dependent on digestion conditions and that ribosomes commonly associate with the 3′UTR, which may have a role in translational regulation.     

Identification of putative sites of interaction between the human formyl peptide receptor and G protein.

Wild-type and 35 mutant formyl peptide receptors (FPRs) were stably expressed in Chinese hamster ovary cells. All cell surface-expressed mutant receptors bound N-formyl peptide with similar affinities as wild-type FPR, suggesting that the mutations did not affect the ligand-binding site. G protein coupling was examined by quantitative analysis of N-formyl-methionyl-leucyl-phenylalanine-induced increase in binding of (35)S-labeled guanosine 5'-3-O-(thio)triphosphate (GTPgammaS) to membranes. The most prominent uncoupled FPR mutants were located in the N-terminal part of the second transmembrane domain (S63W and D71A) and the C-terminal interface of the third transmembrane domain (R123A and C124S/C126S). In addition, less pronounced uncoupling was detected with deletion mutations in the third cytoplasmic loop and in the cytoplasmic tail. Further analysis of some of the mutants that were judged to be uncoupled based on the [(35)S]GTPgammaS membrane-binding assay were found to transduce a signal, as evidenced by intracellular calcium mobilization and activation of p42/44 MAPK. Thus, these single point mutations in FPR did not completely abolish the interaction with G protein, emphasizing that the coupling site is coordinated by several different regions of the receptor. Mutations located in the putative fifth and sixth transmembrane domains near the N- and C-terminal parts of the third cytoplasmic loop did not result in uncoupling. These regions have previously been shown to be critical for G protein coupling to many other G protein-coupled receptors. Thus, FPR appears to have a G protein-interacting site distinct from the adrenergic receptors, the muscarinic receptors, and the angiotensin receptors.     

Revision of <Emphasis Type="Italic">Protohydnum</Emphasis> (Auriculariales,Basidiomycota)

Three species currently addressed to Protohydnum (Auriculariales) are studied with morphological and DNA methods. The genus Protohydnum is retained for the type species only, P. cartilagineum, recently re-collected in Brazil. The European species, P. piceicola, is not congeneric with P. cartilagineum and, therefore, placed in its own genus, Hyalodon, gen. nov. Another Hyalodon species, H. antui, is described from East Asia. The third member of Protohydnum sensu lato, P. sclerodontium from South-East Asia, is transferred to Elmerina.     

Linkage of the long QT syndrome to the short arm of chromosome 11: use of five highly polymorphic markers towards more detailed localization of the mutant gene

The long QT syndrome is an autosomally dominantly inherited cardiac disorder characterized by abnormalities of myocardial repolarization, exercise- or stress-related syncopal attacks and risk of sudden death due to cardiac arrhythmias. Genetic linkage studies have defined three LQT loci on chromosomes 11p15.5, 3q21–24 and 7p35–36. We performed linkage analyses in three Finnish LQT families using five amplifiable markers assigned to chromosome 11p15. By multipoint linkage analyses we obtained a maximal lod score of 5.503, suggesting that the LQT1 locus maps between D11S922 and D11S1338 on chromosome 11. Our data provide a step towards closer definition of the exact borderlines of the LQT1 locus in chromosome 11 and demonstrate markers with high utility in identification of gene carriers in the affected families.