The BUD4 protein of yeast, required for axial budding, is localized to the mother/BUD neck in a cell cycle-dependent manner.

A and alpha cells of the yeast Saccharomyces cerevisiae exhibit an axial budding pattern, whereas a/alpha diploid cells exhibit a bipolar pattern. Mutations in BUD3, BUD4, and AXL1 cause a and alpha cells to exhibit the bipolar pattern, indicating that these genes are necessary to specify the axial budding pattern (Chant, J., and I. Herskowitz. 1991. Cell. 65:1203-1212; Fujita, A., C. Oka, Y. Arikawa, T. Katagi, A. Tonouchi, S. Kuhara, and Y. Misumi. 1994. Nature (Lond.). 372:567-570). We cloned and sequenced BUD4, which codes for a large, novel protein (Bud4p) with a potential GTP-binding motif. Bud4p is expressed and localized to the mother/bud neck in all cell types. Most mitotic cells contain two apparent rings of Bud4 immunoreactive staining, as observed for Bud3p (Chant, J., M. Mischke, E. Mitchell, I. Herskowitz, and J.R. Pringle. 1995. J. Cell Biol. 129: 767-778). Early G1 cells contain a single ring of Bud4p immunoreactive staining, whereas cells at START and in S phase lack these rings. The level of Bud4p is also regulated in a cell cycle-dependent manner. Bud4p is inefficiently localized in bud3 mutants and after a temperature shift of a temperature-sensitive mutant, cdc12, defective in the neck filaments. These observations suggest that Bud4p and Bud3p cooperate to recognize a spatial landmark (the neck filaments) during mitosis and support the hypothesis that they subsequently become a landmark for establishing the axial budding pattern in G1.

O-Glycosylation of Axl2/Bud10p by Pmt4p is required for its stability, localization, and function in daughter cells.

Cells of the yeast Saccharomyces cerevisiae choose bud sites in a manner that is dependent upon cell type: a and alpha cells select axial sites; a/alpha cells utilize bipolar sites. Mutants specifically defective in axial budding were isolated from an alpha strain using pseudohyphal growth as an assay. We found that a and alpha mutants defective in the previously identified PMT4 gene exhibit unipolar, rather than axial budding: mother cells choose axial bud sites, but daughter cells do not. PMT4 encodes a protein mannosyl transferase (pmt) required for O-linked glycosylation of some secretory and cell surface proteins (Immervoll, T., M. Gentzsch, and W. Tanner. 1995. Yeast. 11:1345-1351). We demonstrate that Axl2/Bud10p, which is required for the axial budding pattern, is an O-linked glycoprotein and is incompletely glycosylated, unstable, and mislocalized in cells lacking PMT4. Overexpression of AXL2 can partially restore proper bud-site selection to pmt4 mutants. These data indicate that Axl2/Bud10p is glycosylated by Pmt4p and that O-linked glycosylation increases Axl2/ Bud10p activity in daughter cells, apparently by enhancing its stability and promoting its localization to the plasma membrane.

Multiple genes are required for proper insertion of secretory proteins into the endoplasmic reticulum in yeast.

Genes that function in translocation of secretory protein precursors into the ER have been identified by a genetic selection for mutant yeast cells that fail to translocate a signal peptide-cytosolic enzyme hybrid protein. The new mutants, sec62 and sec63, are thermosensitive for growth and accumulate a variety of soluble secretory and vacuolar precursors whose electrophoretic mobilities coincide with those of the corresponding in vitro translated polypeptides. Proteolytic sensitivity of precursor molecules in extracts of mutant cells confirms that polypeptide translocation is blocked. Some form of interaction among the SEC61 (Deshaies, R. J., and R. Schekman. 1987. J. Cell Biol. 105:633-645), SEC62 and SEC63 gene products is suggested by the observation that haploid cells containing any pair of the mutations are inviable at 24 degrees C and show a marked enhancement of the translocation defect. The translocation defects of two mutants (sec62 and sec63) have been reproduced in vitro. sec63 microsomes display low and thermolabile translocation activity for prepro-alpha-factor (pp alpha F) synthesized with a cytosol fraction from wild type yeast. These gene products may constitute part of the polypeptide recognition or translocation apparatus of the ER membrane. Pulse-chase analysis of the translocation-defective mutants demonstrates that insertion of pp alpha F into the ER can proceed posttranslationally.

Cell division. Septins in common?

Two apparently quite distinct processes, cytokinesis in animal cells and in budding yeast cells, have been shown to involve proteins of the same family, the septins, suggesting that the two may not be so different after all.

Cell division. Bud-site selection is only skin deep.

Yeast cells that divide by budding place new buds in predetermined locations. Recent studies of the subcellular localization of the Bud3 protein help to explain how this occurs.

Molecular genetic dissection of TAF25, an essential yeast gene encoding a subunit shared by TFIID and SAGA multiprotein transcription factors.

We have performed a systematic structure-function analysis of Saccharomyces cerevisiae TAF25, an evolutionarily conserved, single-copy essential gene which encodes the 206-amino-acid TAF25p protein. TAF25p is an integral subunit of both the 15-subunit general transcription factor TFIID and the multisubunit, chromatin-acetylating transcriptional coactivator SAGA. We used hydroxylamine mutagenesis, targeted deletion, alanine-scanning mutagenesis, high-copy suppression methods, and two-hybrid screening to dissect TAF25. Temperature-sensitive mutant strains generated were used for coimmunoprecipitation and transcription analyses to define the in vivo functions of TAF25p. The results of these analyses show that TAF25p is comprised of multiple mutable elements which contribute importantly to RNA polymerase II-mediated mRNA gene transcription.

Histone folds mediate selective heterodimerization of yeast TAF(II)25 with TFIID components yTAF(II)47 and yTAF(II)65 and with SAGA component ySPT7.

We show that the yeast TFIID (yTFIID) component yTAF(II)47 contains a histone fold domain (HFD) with homology to that previously described for hTAF(II)135. Complementation in vivo indicates that the yTAF(II)47 HFD is necessary and sufficient for vegetative growth. Mutation of highly conserved residues in the alpha1 helix of the yTAF(II)47 HFD results in a temperature-sensitive phenotype which can be suppressed by overexpression of yTAF(II)25, as well as by yTAF(II)40, yTAF(II)19, and yTAF(II)60. In yeast two-hybrid and bacterial coexpression assays, the yTAF(II)47 HFD selectively heterodimerizes with yTAF(II)25, which we show contains an HFD with homology to the hTAF(II)28 family We additionally demonstrate that yTAF(II)65 contains a functional HFD which also selectively heterodimerizes with yTAF(II)25. These results reveal the existence of two novel histone-like pairs in yTFIID. The physical and genetic interactions described here show that the histone-like yTAF(II)s are organized in at least two substructures within TFIID rather than in a single octamer-like structure as previously suggested. Furthermore, our results indicate that ySPT7 has an HFD homologous to that of yTAF(II)47 which selectively heterodimerizes with yTAF(II)25, defining a novel histone-like pair in the SAGA complex.

Cellular localization of ovarian proopiomelanocortin messenger RNA during follicular and luteal development in the rat.

Opioid peptides are expressed in the reproductive system and have been reported to regulate reproductive function. The present study used in situ hybridization to selectively localize ovarian cells containing high levels of proopiomelanocortin (POMC) mRNA, an opioid precursor, during different stages of ovarian development. Prepubertal rats were primed with PMSG to stimulate follicular development, followed by hCG to induce ovulation. Treatment groups consisted of control (no treatment), PMSG (2 days post-PMSG), 1 day corpus luteum (CL; 1 day post-hCG), and 8 day CL (8 days post-hCG). POMC mRNA-containing cells were present in antral follicles, CL, and the interstitial compartment. With gonadotropin treatment, the percentage of follicles containing heavily labeled cells increased in the PMSG and 1 day CL groups. The number of POMC mRNA-containing cells per follicle also increased in the 1 day CL group. In the CL, no difference was observed in the percentage of CL exhibiting labeled cells between the 1 day CL and 8 day CL groups; however, more labeled luteal cells per CL were present in the 1 day CL group. A marked increase in POMC mRNA-containing cells was observed in the interstitial compartment of the 1 day CL group. These results indicate that the number of POMC mRNA-containing cells increases with follicular development and CL formation; however, the ovarian distribution suggests that the labeled cells could be nonendocrine cells, possibly white blood cells. The in situ hybridization findings are indicative of low total concentrations of ovarian POMC mRNA, suggesting mainly an autocrine or paracrine role for POMC or POMC-derived peptides.(ABSTRACT TRUNCATED AT 250 WORDS)

Identification and characterization of metalloproteinase inhibitor activity in human ovarian follicular fluid.

Metalloproteinase inhibitors regulate collagenase activity in the extracellular matrix. To assess the role of metalloproteinase inhibitors in the ovulatory process, inhibitor activity was examined in human follicular fluid collected 2-4 h before ovulation. The relationship between inhibitor activity and steroid content was determined, and the inhibitors were partially purified and characterized. Inhibitory activity in follicular fluid (n = 25) correlated with both follicular estradiol (P less than 0.001) and progesterone (P less than 0.02) concentrations per follicle. Chromatographic separation of the follicular fluid on Sepharose 6B isolated two peaks of inhibitory activity. The inhibitor from the small mol wt (Mr) peak shared many of the properties of tissue inhibitors of metalloproteinase. It was stable in response to heat (60 C) and methylamine (200 mM), and was destroyed by reduction and alkylation, a procedure reported to destroy previously characterized inhibitors. Partial purification by affinity and ion exchange chromatography demonstrated the inhibitor to be a glycoprotein with an approximate Mr of 28-29K. The large Mr inhibitor had an approximate size of 700K and exhibited many of the characteristics of alpha 2-macroglobulin, a serum-derived metalloproteinase inhibitor. It was sensitive to heat, methylamine, and reduction and alkylation. Thus, follicular fluid contains metalloproteinase inhibitor activity that is steroid related and may be hormonally regulated. Ovarian metalloproteinase inhibitors may act to regulate connective tissue remodeling during follicular rupture.

Androgen production by monkey luteal cell subpopulations at different stages of the menstrual cycle.

Androgens produced by the primate corpus luteum (CL) serve as precursors for estrogen synthesis; moreover, detection of androgen receptors in luteal tissue suggests a regulatory role within the CL. To determine the cellular source(s) and agonist regulation of androgen production during the lifespan of the primate CL, luteal tissues were collected from rhesus monkeys in the early (days 3-5 post-LH surge), mid (days 7-8), mid-late (days 11-12), and late (days 14-15) luteal phase of the menstrual cycle. Collagenase-dispersed cells (i.e., mixed cells) were analyzed by flow cytometry based on light scatter properties and sorted into populations of small (< or = 15 microns) and large (> 20 microns) luteal cells. Cells (n = 4 animals/stage) were incubated in Ham's F-10 and 0.1% BSA for 3 h at 37 C with or without hCG (100 ng/mL), PGE2 (14 mumol/L), or dibutyryl cAMP (dbcAMP; 5 mmol/L), and androstenedione (A4) and testosterone were measured. Basal A4 production by large cells was markedly higher (P < 0.05) than that by small cells (e.g. mid-late luteal phase, 821 +/- 188 vs. 69 +/- 25 pg/mL.5 x 10(4) cells/3 h; mean +/- SEM), whereas that by mixed cells was intermediate (317 +/- 205 pg/mL). In the early luteal phase, hCG stimulated A4 synthesis by mixed (1.6-fold; P < 0.05) and large (3.1-fold; P < 0.05) luteal cells, but not by small cells (1.3-fold). By the mid-late luteal phase, hCG did not increase A4 production by any cell type, although hCG responsiveness returned to large cells (2.0-fold increase; P < 0.05) by the late luteal phase. PGE2 responsiveness by cell types was similar to that of hCG, except large cell responsiveness did not return in the late luteal phase. In all cell types, dbcAMP stimulated the largest increase in A4 levels; in the mid-late luteal phase, small and large cells responded to dbcAMP with 8.2- and 3.0-fold increases (P < 0.05) in A4 production, respectively. When luteal cells were incubated with the steroidogenic substrates, 17 alpha-hydroxyprogesterone or 17 alpha-hydroxypregnenolone (1 mumol/L), large cells produced much more (P < 0.05) A4, testosterone, estrone, and estradiol than small cells. Both substrates elicited similar patterns of androgen production, with A4 synthesis predominant in all luteal cell types. Thus, cell subpopulations in the primate CL can be distinguished by their ability to produce androgen and estrogen. Changes in agonist-responsive androgen production may influence the local steroid milieu and function of the CL during the menstrual cycle.

D1-Receptor, DARPP-32, and PP-1 in the primate corpus luteum and luteinized granulosa cells: evidence for phosphorylation of DARPP-32 by dopamine and human chorionic gonadotropin.

The multifunctional phosphoprotein "dopamine and cAMP-related phosphoprotein, M(r) 32,000" (DARPP-32), which is able to act as an intracellular third messenger, was previously found to be present in human luteinized granulosa cells (GCs) and human ovary. DARPP-32 phosphorylation in GCs was increased by dopamine (DA) acting via a DA-1 receptors (D1-R). In the present study, we examined whether the major endocrine signaling molecule for GCs, LH/human CG (hCG), could also affect DARPP-32 phosphorylation. Immunoprecipitation studies showed that hCG, as well as DA, increased phosphorylation of DARPP-32 at threonine residues within 10 min, indicating that the signal transduction pathways of a hormone and a neurotransmitter involve DARPP-32 in GCs. Phosphorylated DARPP-32 is known to inhibit a cellular phosphatase (PP-1), which was also found to be expressed by GCs. Using RT-PCR and sequence analyses we showed that DARPP-32, PP-1, and D1-R genes were not restricted to cultured luteinized GCs, but were expressed in vivo, in the corpus luteum (CL) of the rhesus monkey throughout its entire life span. Whereas hCG increased steroid production in monkey luteinized GCs and in isolated luteal cells, DA failed to affect basal or hCG-stimulated progesterone production. This indicates that, unlike the LH/hCG receptor, the D1-R is not directly linked to steroid production. Although the precise role of D1-R in the CL remains to be shown, the presence of D1-R, DARPP-32, and its target PP-1 in this endocrine tissue, as well as the phosphorylation of DARPP-32 by a gonadotropin and by DA in luteinized GCs, indicate that the signal transduction pathways of the neurotransmitter DA and the gonadotropin hCG/LH involve DARPP-32. The PP-1 inhibitor DARPP-32 may, thus, be a third messenger used by both DA and hCG/LH to exert common regulatory influences on the cells of the CL.

The role of ovarian proteases and their inhibitors in ovulation.

To assess the role of inhibitors of proteolytic enzymes, such as plasminogen activator (PA) and collagenase in the ovulatory process, inhibitor activity and mRNA levels were examined in periovulatory rat and human ovaries. In the rat, immature animals received 20 IU of pregnant mare serum gonadotropin (PMSG) followed 52 h later by 10 IU of hCG. Ovaries were removed at intervals from 0 to 20 h after human chorionic gonadotropin (hCG) administration. Inhibitor activity for metalloproteinases, such as collagenase, increased from 60.5 +/- 4.1 inhibitor units/ovary at 0 h (i.e., time of hCG treatment) to a maximum of 218.2 +/- 11.4 units/ovary at 8 h after hCG before decreasing at 12 h (time of ovulation) and 20 h (122.2 +/- 7.9 and 71.6 +/- 8.1 units/ovary, respectively). Human follicular fluid and granulosa cells were obtained from preovulatory follicles of patients in our in vitro fertilization program. Metalloproteinase inhibitor activity was evaluated in follicular fluid as well as the levels of PA and PA inhibitor (PAI) mRNA by Northern analysis. Increasing metalloproteinase inhibitor activity was positively correlated with follicular levels of estradiol (p less than 0.001) and progesterone (p less than 0.02, N = 26). Chromatographic separation of follicular fluid resulted in two peaks of metalloproteinase inhibitor activity. The large molecular weight (MW) inhibitor had an approximate size of 700 kilodaltons (kDa) and may represent alpha 2-macroglobulin, a serum-derived inhibitor. The small MW inhibitor shared many of the characteristics of tissue-derived inhibitors of metalloproteinases. Partial purification of the small MW inhibitor by Concanavalin A-Sepharose and Heparin-Sepharose chromatography demonstrated the inhibitor to be a glycoprotein with an approximate MW = 28-29 K. Northern analysis of human granulosa cell total RNA from preovulatory follicles showed little or no detectable tissue-type PA or urokinase-type PA mRNA. In contrast, two species of PA inhibitor type-1 mRNA were detected in relative abundance. The present findings demonstrate the presence of proteolytic inhibitors in periovulatory ovaries of the rat and human. These ovarian inhibitors may play a role in regulating connective tissue remodeling during follicular rupture.

Antibiotics for acute otitis media in children.

BACKGROUND: Acute otitis media is one of the most common diseases in early infancy and childhood. Antibiotic use for acute otitis media varies from 31% in the Netherlands to 98% in the USA and Australia. OBJECTIVES: The objective of this review was to assess the effects of antibiotics for children with acute otitis media. SEARCH STRATEGY: We searched the Cochrane Controlled Trials Register, MEDLINE, Index Medicus (pre 1965), Current Contents and reference lists of articles from 1958 to January 2000. SELECTION CRITERIA: Randomised trials comparing antimicrobial drugs with placebo in children with acute otitis media. DATA COLLECTION AND ANALYSIS: Three reviewers independently assessed trial quality and extracted data. MAIN RESULTS: Ten trials were eligible but only seven trials, with a total of 2,202 children, included patient-relevant outcomes. The methodological quality of the included trials was generally high. All trials were from developed countries. The trials showed no reduction in pain at 24 hours, but a 28% relative reduction (95% confidence interval 15% to 38%) in pain at two to seven days. Since approximately 80% of patients will have settled spontaneously in this time, this means an absolute reduction of 5% or that about 17 children must be treated with antibiotics to prevent one child having some pain after two days. There was no effect of antibiotics on hearing problems of acute otitis media, as measured by subsequent tympanometry. However, audiometry was done in only two studies and incompletely reported. Nor did antibiotics influence other complications or recurrence. There were few serious complications seen in these trials: only one case of mastoiditis occurred in a penicillin treated group. REVIEWER'S CONCLUSIONS: Antibiotics provide a small benefit for acute otitis media in children. As most cases will resolve spontaneously, this benefit must be weighed against the possible adverse reactions. Antibiotic treatment may play an important role in reducing the risk of mastoiditis in populations where it is more common. [This abstract has been prepared centrally.]

Antibiotics for acute otitis media in children.

BACKGROUND: Acute otitis media is one of the most common diseases in early infancy and childhood. Antibiotic use for acute otitis media varies from 31% in the Netherlands to 98% in the USA and Australia. OBJECTIVES: The objective of this review was to assess the effects of antibiotics for children with acute otitis media. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE, Index Medicus (pre 1965), Current Contents and reference lists of articles from 1958 to January 2000. The search was updated in 2003. SELECTION CRITERIA: Randomised trials comparing antimicrobial drugs with placebo in children with acute otitis media. DATA COLLECTION AND ANALYSIS: Three reviewers independently assessed trial quality and extracted data. MAIN RESULTS: Ten trials were eligible based on design, only eight of the trials, with a total of 2,287 children, included patient-relevant outcomes. The methodological quality of the included trials was generally high. All trials were from developed countries. The trials showed no reduction in pain at 24 hours, but a 30% relative reduction (95% confidence interval 19% to 40%) in pain at two to seven days. Since approximately 80% of patients will have settled spontaneously in this time, this means an absolute reduction of 7% or that about 15 children must be treated with antibiotics to prevent one child having some pain after two days. There was no effect of antibiotics on hearing problems of acute otitis media, as measured by subsequent tympanometry. However, audiometry was done in only two studies and incompletely reported. Nor did antibiotics influence other complications or recurrence. There were few serious complications seen in these trials: only one case of mastoiditis occurred in a penicillin treated group. REVIEWER'S CONCLUSIONS: Antibiotics provide a small benefit for acute otitis media in children. As most cases will resolve spontaneously, this benefit must be weighed against the possible adverse reactions. Antibiotic treatment may play an important role in reducing the risk of mastoiditis in populations where it is more common.

Salmonella typhimurium pancreatic abscess: report of a case.

A case of pancreatic abscess from Salmonella typhimurium is reported. After surgical drainage of the abscess, positive stool cultures persisted. Finally, after intensive antimicrobial therapy with tetracycline and chloramphenicol, and cholecystectomy, stool cultures became negative. This is, to our knowledge, the first published case of S. typhimurium pancreative abscess.

Bile salt inhibits acid-promoting feeding tube occlusion.

Occlusion of feeding tubes is a common and costly complication of enteral feeding. Although the composition of feeding formulas, the size, design, and material of the feeding tube, and the rate of delivery have been considered as factors that determine the rate of tube occlusion, little information is available on the effect of the luminal content of the gut on tube occlusion. Enteral feeding tubes are placed either in the stomach or postpylorically, in the small intestine. The chemical composition of these regions including acidity and bile salt concentration may vary. Since acidity has been shown to promote tube occlusion and bile salts have detergent-like properties, these chemical differences in the luminal environment may be important to tube occlusion. To test the idea that bile salt inhibits acid-promoted occlusion of feeding tubes, in an in vitro study, we compared the time-to-complete occlusion of four groups of formula-filled feeding tubes (six tubes in each group) immersed in an acidic solution (pH 3.0) containing 0 (control), 10, 20, or 40 mM of taurocholate. We found that although 33% of the feeding tubes were occluded within 12 hours in the absence of exposure to bile salt, none were occluded when 20 or 40 mM of taurocholate was added to the acidic solution. After 24 hours, 40 mM of taurocholate inhibited acid-promoted occlusion of 67% of the feeding tubes. Thus 0 to 40 mM of taurocholate still inhibited acid-promoted tube occlusion in a dose-dependent fashion (p < .05). Acidity and the concentration of bile salt may work together, but in opposite directions, as luminal factors that determine the rate of occlusion of feeding tubes.

Pressure ulcers, Part 1: Prevention strategies.

Pressure ulcers are a costly health concern. Many can be prevented by conscientious, vigorous nursing care. The nurse practitioner (NP) is an ideal professional to direct preventive care and to manage the treatment of ulcers. This article reviews the multiple risk factors and dynamics involved in the development of pressure ulcers, and preventive measures that can be implemented. The role of an NP related to pressure ulcer prevention and specific NP interventions are discussed.

Pressure ulcers, Part two: Management strategies.

The goal of this article is to facilitate the successful resolution of pressure ulcers. The nurse practitioner (NP) is an ideal health care professional to manage pressure ulcer care. This article reviews the basic principles related to wound care. The healing trajectory is discussed to assist an NP to determine appropriate therapy. Current, research-based management strategies are provided.