Preparation for fatherhood: A role for olfactory communication during human pregnancy?

There is evidence across a range of bi-parental species that physiological changes may occur in partnered males prior to the birth of an infant. It has been hypothesised that these hormonal changes might facilitate care-giving behaviours, which could augment infant survival. The mechanism that induces these changes has not been identified, but evidence from several species suggests that odour may play a role. The current study investigated this in humans by recording testosterone and psychological measures related to infant interest and care in men (n = 91) both before and after exposure to odours from either pregnant women or non-pregnant control women. We found no evidence for an effect of odour cues of pregnancy on psychological measures including self-reported sociosexual orientation and social dominance scores, ratings of infant or adult faces, or testosterone levels. However, we found that brief exposure to post-partum odours significantly increased the reward value of infant faces. Our study is the first to show that the odour of peri-partum women may lead to upregulation of men's interest in infants.

Regulation of surfactant phosphatidylcholine secretion from alveolar type II cells during Pneumocystis carinii pneumonia in the rat.

We used an immunosuppressed rat model to test the hypothesis that normal mechanisms regulating surfactant phosphatidylcholine synthesis and secretion in alveolar type II cells are aberrant in Pneumocystis carinii pneumonia. Animal groups included: group 1, healthy controls; group 2, immunosuppressed, without pneumocystosis; group 3, immunosuppressed with pneumocystosis; group 4, immunosuppressed with well-established pneumocystosis treated with trimethoprim-sulfamethoxazole (TMP-SMX). Type II cells were isolated from rats in each group and compared for [3H]choline incorporation into phospholipid and response of the type II cells to secretagogues. Incorporation of [3H]choline into phospholipid subclasses exhibited significant differences. Incorporation into phosphatidylcholine fell from 89.3 +/- 2.2% of total incorporation in group 1 control rats to 79.6 +/- 3.1% in group 3 rats with P. carinii pneumonia, while incorporation into sphingomyelin rose from 5.6 +/- 1.2% in group 1 animals to 15.2 +/- 2.7% in group 3 rats. Incorporation of [3H]choline into phospholipid subclasses in cells from group 2 and group 4 animals was not different from incorporation for group 1 animals. Type II cells from group 1 and group 2 (immunosuppressed control) rats responded appropriately to the secretagogues ATP, TPA, and terbutaline with a marked increase in surfactant phosphatidylcholine secretion; the effect of ATP was also blocked by the lectin, concanavalin A. In contrast, type II cells from group 3 rats failed to respond to the secretagogues with a significant increase in phospholipid secretion. Although treatment of group 4 rats with TMP-SMX markedly reduced the P. carinii organism burden, type II cells from these animals also responded poorly to the secretagogues. The depressed type II cell function described here provides a mechanism for the observed decrease in surfactant phospholipids from bronchoalveolar lavage fluid of experimental animals and patients with P. carinii pneumonia. The data also suggest this defect may become irreversible with advanced disease.

Measurement of rRNA Variations in Natural Communities of Microorganisms on the Southeastern U.S. Continental Shelf.

The development of a clear understanding of the physiology of marine prokaryotes is complicated by the difficulties inherent in resolving the activity of various components of natural microbial communities. Application of appropriate molecular biological techniques offers a means of overcoming some of these problems. In this regard, we have used direct probing of bulk RNA purified from selective size fractions to examine variations in the rRNA content of heterotrophic communities and Synechococcus populations on the southeastern U.S. continental shelf. Heterotrophic communities in natural seawater cultures amended with selected substrates were examined. Synechococcus populations were isolated from the water column by differential filtration. The total cellular rRNA content of the target populations was assayed by probing RNA purified from these samples with an oligonucleotide complementing a universally conserved region in the eubacterial 16S rRNA (heterotrophs) or with a 1.5-kbp fragment encoding the Synechococcus sp. strain WH 7803 16S rRNA (cyanobacteria). The analyses revealed that heterotrophic bacteria responded to the addition of glucose and trace nutrients after a 6-h lag period. However, no response was detected after amino acids were added. The cellular rRNA content increased 48-fold before dropping to a value 20 times that detected before nutrients were added. Variations in the rRNA content from Synechococcus spp. followed a distinct diel pattern imposed by the phasing of cell division within the irradiance cycle. The results indicate that careful application of these appropriate molecular biological techniques can be of great use in discerning basic physiological characteristics of selected natural populations and the mechanisms which regulate growth at the subcellular level.

A comparison of bathophenanthrolinedisulfonic acid and ferrozine as chelators of iron(II) in reduction reactions.

Bathophenanthrolinedisulfonic acid (4,7-diphenyl-1,10-phenanthrolinedisulfonic acid [BPS]) and 3-(2-pyridyl)-5,6-bis(4-phenylsulfonic acid)-1,2,4-triazine (ferrozine), chelators of ferrous iron, are often used to determine iron(II) concentrations in various samples and for identifying or measuring iron reduction in biological systems. In this study, the efficacy of ferrozine and BPS to chelate iron(II) reduced from Fe(3+)-ligands by selected reducing agents was determined. Our results indicate that (i) BPS and ferrozine are not equivalent as kinetic indicators of iron reducing activity; (ii) apparent initial rates of reduction of Fe(3+)-ligands by dithiothreitol, as indicated by formation of complexes of iron(II) with either BPS or ferrozine, differed by a factor of 50; and (iii) nonspecific reduction of some Fe(3+)-ligands by both BPS and ferrozine occurred. Under identical conditions, rates of formation of Fe(2+)-ferrozine generally were slower than rates of formation of Fe(2+)-BPS. These data suggest careful consideration should be given in the design of any experiments where kinetics of iron reduction are monitored with BPS or ferrozine.

Use of the API rapid NFT system for identifying nonfermentative and fermentative marine bacteria.

Thirty-five American Type Culture Collection type strains of marine bacteria were used to evaluate the Rapid NFT system (API Analab Products, Plainview, N.Y.) for use in identifying heterotrophic marine bacteria. The 21 biochemical and assimilation tests on the Rapid NFT test strips were treated according to the manufacturer's protocol, which included use of AUX medium (provided with the Rapid NFT system) for preparing assimilation tests, and by substituting phenol red broth base (BBL Microbiology Systems, Cockeysville, Md.) with and without an oil overlay for the AUX medium. A seven-digit numerical profile was obtained for each NFT test strip from each of the three procedures and matched to its corresponding number in the Rapid NFT identification codebook. Also, all biochemical and assimilation test results were analyzed with SASTAXAN and SAS/GRAPH programs (SAS Institute, Inc., Cary, N.C.); similarity matrices were computed for all 35 strains. For comparison purposes, bacterial strains were grouped at a similarity level of 70%. The results indicated a low efficacy of identification for all three procedures. In addition, similarity matrix analysis showed more cohesive grouping based on results of phenol red broth base-treated strains than for the AUX medium provided by the manufacturer. However, none of the three treatments provided exclusive grouping of type strains at the genus level. Thus, the reliability of the data obtained from the NFT system and modifications thereof should be evaluated carefully when environmental isolates are characterized.

Variations in rRNA content of marine Vibrio spp. during starvation-survival and recovery.

The degree and temporal context of variations in ribosome content during nutrient starvation of two copiotrophic marine bacteria, Vibrio alginolyticus and Vibrio furnissii, have been examined. The organisms were starved either by nutritional shift-down or by consumption of limiting nutrients resulting from growth into stationary phase. Measurements of the amount of hybridization to 16S rRNA-specific probes revealed that the cells retained between 10 and 26% of their original rRNA content after 15 days of starvation. In V. alginolyticus, losses in stationary-phase cells occurred rapidly (1 to 2 days), whereas cells shifted into starvation remained larger and retained considerably more rRNA. The ability of V. alginolyticus to recover from starvation was assessed after cells were maintained for 2, 8, and 15 days in nutrient-depleted medium. The pattern of recovery at the level of rRNA accumulation depended upon the duration of nutrient deprivation and the manner in which it was imposed. Stationary-phase cells starved for 2 days had only slight relative increases in rRNA levels after excess nutrients were added. As the duration of starvation lengthened to 8 and 15 days, increasingly greater amounts of rRNA (30 and 70 times preenrichment values, respectively) were transcribed after nutrient enrichment. Shift-down cells recovered from 2 and 8 days of starvation without extensive rRNA production. After 15 days, nutrient enrichment caused 16S rRNA levels to increase 30-fold. The results indicate that the mechanisms controlling starvation-survival in these marine bacterial species are linked to the physiological state at the onset of starvation and that the subsequent pattern of recovery will depend upon how starvation was initiated.

P2-purinoceptor regulation of surfactant phosphatidylcholine secretion. Relative roles of calcium and protein kinase C.

Ca2+ and protein kinase C have both been proposed as intracellular signals for subsequent phosphatidylcholine secretion by alveolar Type II cells. We have determined the relative roles of Ca2+ and protein kinase C in regulating surfactant phosphatidylcholine secretion by utilizing exogenous ATP and the phorbol ester TPA (12-O-tetradecanoylphorbol 13-acetate) as secretagogues, along with MAPTAM to chelate intracellular Ca2+ and sphingosine to inhibit endogenous protein kinase C. Exposure of Type II cells to the P2-purinoceptor agonist, ATP, results in a dose-dependent increase in surfactant phosphatidylcholine secretion from isolated alveolar Type II cells with an EC50 (concn. producing 50% of maximal response) of 2 microM. Administration of exogenous ATP to Type II cells also results in a dose-dependent increase in inositol trisphosphate production, Ca2+ mobilization and [3H]phorbol 12,13-dibutyrate ([3H]PDBu) binding as a measure of protein kinase C translocation. The EC50 in each case is 1-5 microM, indicating association of these events with surfactant phosphatidylcholine secretion. Loading Type II cells with non-hydrolysable GTP analogue (GTP[S]) inhibited ATP-induced Ca2+ mobilization, supporting the hypothesis that Type II cell P2-purinoceptors are coupled to phospholipase C via a GTP-binding protein. The ATP-induced elevation of cytosolic Ca2+ was also inhibited by MAPTAM (a cell-permeant EGTA analogue) by 90%, but MAPTAM was without effect on surfactant phosphatidylcholine secretion induced by ATP. Sphingosine inhibited both ATP- and TPA-induced surfactant phosphatidylcholine secretion as well as [3H]PDBu binding with a similar IC50 (concn. producing 50% of maximal inhibition) (10 microM). Sphingosine did not affect surfactant phosphatidylcholine secretion induced by terbutaline and did not have a significant effect on Ca2+ mobilization induced by exogenous ATP. These results are consistent with a prominent role for protein kinase C in regulation of P2-purinoceptor-induced surfactant phosphatidylcholine secretion, and indicate that Ca2+ mobilization is not a necessary step for ATP-induced surfactant phosphatidylcholine secretion.

Calcium mobilization and response recovery following P2-purinoceptor stimulation of rat isolated alveolar type II cells.

1. The effect of adenosine 5'-triphosphate (ATP) on surfactant phospholipid secretion, calcium mobilization, and the time course for recovery of the response system was studied in isolated alveolar Type II cells of the rat. 2. ATP (10 microM) stimulated a biphasic intracellular Ca2+ transient monitored by changes in Fura-2 fluorescence, from a basal level of 126 +/- 9 nM, to a rapid peak of 391 +/- 1 nM, followed by a prolonged plateau 26 +/- 4 nM above baseline (mean +/- s.e.mean, n = 26). 3. ATP-stimulated surfactant phospholipid secretion and peak Ca2+ levels had similar EC50s (1 x 10(-6) M), and were unaffected by chelation of extracellular Ca2+. However, the prolonged plateau phase was abolished by chelation of extracellular Ca2+. 4. There was a 15 min refractory period before full recovery of the Ca2+-response to ATP. Recovery was dependent on extracellular Ca2+, was accelerated by removing extracellular agonist and was prolonged following stimulation with the poorly hydrolyzed ATP analogue, ATP-gamma-S. 5. While the Type II cell was capable of multiple ATP-induced Ca2+ transients following recovery, no additional surfactant phospholipid was released with sequential stimulation. 6. These findings suggest initial exposure of Type II cells to ATP mobilizes intracellular Ca2+, stimulates phospholipid secretion and rapidly desensitizes the cell to further stimulation by ATP. Recovery of the ATP-induced Ca2+-response depends on presence of extracellular Ca2+ and removal of agonist.

Reactive blue 2 selectively inhibits P2y-purinoceptor-stimulated surfactant phospholipid secretion from rat isolated alveolar type II cells.

1. The effect of reactive blue 2 on adenosine 5'-triphosphate (ATP), 12-O-tetradecanoylphorbol 13-acetate (TPA) and terbutaline-induced surfactant phospholipid secretion from rat isolated alveolar Type II cells was studied. 2. Reactive blue 2 significantly inhibited ATP-induced surfactant phospholipid secretion, but was without effect on C-kinase agonist (TPA) or beta-adrenoceptor agonist (terbutaline)-stimulated surfactant phospholipid secretion. The IC50 for inhibition of ATP-induced surfactant secretion was 1.5 x 10(-4)M. 3. These data are consistent with a P2y-purinoceptor regulating surfactant phospholipid secretion from isolated Type II cells and support previous work suggesting reactive blue 2 is a specific inhibitor at P2y-purinoceptors.

A marine Micrococcus produces metabolites ascribed to the sponge Tedania ignis.

Extracts of the sponge Tedania ignis have been reported to contain several diketopiperazines. As part of an investigation of the commensal and symbiotic microflora of sponges, we have consistently isolated, from specimens of T. ignis, a Micrococcus sp. which produces diketopiperazines in laboratory cultural media. This is the first demonstration that a bacterium associated with a sponge produces secondary metabolites ascribed to the sponge host.

Regulation of surfactant phospholipid secretion from isolated rat alveolar type II cells by lectins.

The major surfactant-associated protein is a potent inhibitor of surfactant phospholipid secretion from isolated type II cells. Since the major surfactant-associated protein contains a carboxy terminal polypeptide domain which is homologous to the lectin-like liver mannose-binding protein, we tested whether lectins inhibit surfactant phospholipid secretion from rat alveolar type II cells. Concanavalin A, wheat germ agglutinin and Maclura pomifera agglutinin were potent inhibitors of surfactant phospholipid secretion. When adenosine 5'-triphosphate (ATP) was utilized as a secretagogue, the IC50 values for inhibition of surfactant phospholipid secretion were 5.10(-7) (wheat germ agglutinin), 1.10(-6) (concanavalin A) and 2.5.10(-5) M (M. pomifera agglutinin). Similar results were obtained when 12-O-tetradecanoylphorbol 13-acetate was utilized as a secretagogue: IC50 values of 1.10(-6) M for concanavalin A and wheat germ agglutinin and 2.5.10(-5) M for M. pomifera agglutinin. Hapten sugars were utilized to antagonize the inhibitory effect of the lectins. N-Acetyl-D-glucosamine significantly reversed inhibition of phospholipid secretion by wheat germ agglutinin in a dose-dependent fashion and methyl alpha-D-mannoside significantly reversed inhibition of phospholipid secretion by concanavalin A. N-Acetyl-D-galactosamine had no significant effect on inhibition of secretion produced by any of the lectins. The inhibitory effect of the lectins did not appear to be due to cytotoxicity since lactate dehydrogenase was not released above control levels and the inhibition of the surfactant phospholipid secretion by wheat germ agglutinin could be reversed after treatment of cells with wheat germ agglutinin by washing the lectin from the cells followed by treatment of the cells with ATP. These studies demonstrate a direct inhibitory effect of plant lectins on phospholipid secretion from type II cells in vitro.

Surfactant-associated protein inhibits phospholipid secretion from type II cells.

Secretion of [3H]phosphatidylcholine ([3H]PC) from isolated rat pulmonary type II epithelial cells was inhibited by the surfactant-associated protein of Mr = 35,000 (SAP-35) purified from canine lung surfactant. SAP-35 inhibited [3H]PC secretion in a dose-dependent manner and significantly inhibited basal, phorbol ester, beta-adrenergic, and P2-purinergic agonist-induced [3H]PC secretion. SAP-35 significantly inhibited [3H]PC secretion from 1 to 3 h after treatment. The IC50 for inhibition of [3H]PC secretion by canine SAP-35 was 1-5 X 10(-6) g/ml and was similar for inhibition of both basal and secretagogue-stimulated release. Heat denaturation of SAP-35, addition of monoclonal anti-SAP-35 antibody, reduction and alkylation of SAP-35, or association of SAP-35 with phospholipid vesicles reversed the inhibitory effect on secretagogue-induced secretion. Inhibitory effects of SAP-35 were observed 3 h after cells were washed with buffer that did not contain SAP-35. Although SAP-35 enhanced reassociation of surfactant phospholipid with isolated type II cells, its inhibitory effect on secretion of [3H]PC did not result from stimulation of reuptake of secreted [3H]PC by type II cells. The inhibition of phospholipid secretion by SAP-35 was also not due to inhibition of PC or disaturated PC synthesis by SAP-35. SAP-35, the major phospholipid-associated protein in pulmonary surfactant, is a potent inhibitor of surfactant secretion from type II cells in vitro and may play an important role in homeostasis of surfactant in the alveolar space.

P2Y-purinoceptor regulation of surfactant secretion from rat isolated alveolar type II cells is associated with mobilization of intracellular calcium.

1 The effect of methylene, thio, and imido substituted analogues of adenosine 5'-triphosphate (ATP) on surfactant phospholipid secretion and calcium mobilization in rat isolated alveolar Type II cells was studied. 2 ATP was the most potent secretagogue of adenine nucleotides studied. The rank order of agonist potency for [3H]-phosphatidylcholine secretion was ATP greater than adenosine 5'-O-(3-thiotriphosphate) (gamma S-ATP) greater than beta, gamma-imido adenosine 5'-triphosphate (AMPPNP) greater than beta, gamma-methylene adenosine 5'-triphosphate (beta, gamma-CH2-ATP) greater than alpha, beta-methylene adenosine 5'-triphosphate (alpha, beta-CH2-ATP). The respective EC50S were 10(-6) M, 2 X 10(-6) M, 2 X 10(-5) M, and greater than 2.5 X 10(-4) M. 3 Exogenous ATP also induced a rapid mobilization of intracellular calcium monitored by changes in Fura 2 fluorescence. The rank order of agonist potency for calcium mobilization was similar to the rank order of agonist potency for surfactant secretion: ATP = gamma S-ATP greater than AMPPNP greater than alpha, beta-CH2-ATP. 4 There was no effect of EGTA on ATP-induced calcium mobilization, consistent with the hypothesis that exogenous ATP induces release of calcium from intracellular stores. 5 These data are consistent with a P2Y-purinoceptor regulating surfactant secretion from isolated Type II cells via mobilization of intracellular calcium, since: (a) non-hydrolyzed analogues of ATP are potent secretagogues, (b) beta, gamma-CH2-ATP was a more potent secretagogue than alpha, beta-CH2-ATP and (c) the rank orders of agonist potency for calcium mobilization and phospholipid secretion were the same.

The fate of enteric pathogenic bacteria in estuarine and marine environments.

Sufficient laboratory and field data are now available to hypothesize that enteric pathogens survive for very long periods of time in sea-water. In fact, these Gram-negative bacteria probably enter into dormancy, during which they remain viable and potentially virulent, yet are non-culturable when traditional bacteriological methods are employed. Increasing use of the world's oceans-for discharge of domestic wastes may result in public health problems in the future from the allochthonous human pathogens accumulating in the marine environment at disposal sites.

Regulation of surfactant secretion from isolated Type II pneumocytes by substance P.

Substance P, an eleven amino acid neuropeptide, significantly inhibited release of [3H]phosphatidylcholine from pulmonary Type II epithelial cells in vitro. Basal release and release in response to the beta-adrenergic agonist, terbutaline and 12-O-tetradecanoylphorbol 13-acetate (TPA) were significantly decreased in the presence of substance P. Inhibitory effects of substance P were noted following a 1 h exposure of primary cultures of Type II cells in vitro and persisted up to 3 h in the presence of the secretagogues, TPA and terbutaline. The IC50 values for substance P inhibition of [3H]PC release were 10 microM for basal release, 40 microM for TPA-induced release and 50 microM for terbutaline-induced release. The related neuropeptide, physalaemin and the stable active analog of substance P, [pGlu5, MePhe8, MeGly9]substance P [5-11], had no significant inhibitory effects on surfactant release whether in the presence or absence of TPA or terbutaline. These data support the hypothesis that NH2-terminal basic groups of substance P are necessary for inhibition of surfactant secretion from isolated Type II cells and support the concept that an inhibitory system contributes to mediation of surfactant secretion from Type II epithelial cells.

P2-purinoceptors regulate surfactant secretion from rat isolated alveolar type II cells.

Rat isolated alveolar Type II cells were utilized to examine the effect of purine and pyrimidine analogues on secretion of pulmonary surfactant. ATP potently stimulated [3H]-phosphatidylcholine ([3H]-PC) secretion in a time- and dose-dependent manner. The effect of ATP was noted by one hour of exposure and persisted for three hours. The EC50 (concentration producing 1/2 the maximal response) for ATP-induced [3H]-PC secretion was 100 nM. ADP was also a potent secretagogue for surfactant secretion, but AMP and adenosine had no significant effect on surfactant secretion at concentrations less than or equal to 250 microM. The EC50 for ADP-induced [3H]-PC secretion was 250 nM. Other purine and pyrimidine nucleotides (ITP, GTP, CTP, TTP) were examined for their effect on [3H]-PC secretion. All purine and pyrimidine triphosphates examined significantly augmented [3H]-PC secretion, but were much less potent than ATP. The EC50s were ITP = 10 microM; GTP = 100 microM; CTP = 250 microM; TTP = 100 microM. Neither 8-phenyltheophylline (10 microM, a P1-purinoceptor antagonist), propranolol (100 microM, a beta-adrenoceptor antagonist), nor indomethacin (10 microM, a prostaglandin synthetase inhibitor) inhibited ATP-induced [3H]-PC secretion from isolated Type II cells. These data provide evidence for regulation of surfactant secretion from alveolar Type II cells by a P2-purinoceptor.

Allogenic succession of marine bacterial communities in response to pharmaceutical waste.

Vibrio spp. predominated in the culturable bacterial community of surface waters of the Puerto Rico Trench at the site of disposal for nearly ten years of pharmaceutical wastes. In this area and surrounding waters as far as 1000 km north of the dumpsite and south into the Caribbean Sea, Vibrio spp. comprised up to 100% of the culturable bacteria, with Acinetobacter spp. being the second most prevalent group. Pseudomonas spp., reported to be common in these waters a decade earlier, were virtually absent from all samples examined during a three year study involving 9 cruises. Staphylococcus spp. were also found in water samples collected within the dumpsite. Using cultures isolated from surface water samples collected at the dumpsite, laboratory experiments confirmed that pharmaceutical waste can enrich for Vibrio spp., in preference to Pseudomonas spp., with growth of the strains proportional to the amount of waste added.

A Cytophaga species endotoxin as a putative agent of occupation-related lung disease.

A previous study suggested that a biologically active bacterial endotoxin was a putative agent of lung disease in a textile-producing facility. The endotoxin was isolated from the biomass growing in a chilled-water spray air humidification system. The bacterial flora of the air humidification system were isolated and taxonomically identified to the genus level. By using indirect immunofluorescence assays, a serologically reactive Cytophaga species was identified. A serologically reactive, biologically active (Limulus assay) endotoxin was purified from phenol extracts of the Cytophaga species. The endotoxin contained sugars, hexosamines, and lipids identical to those found in the humidifier biomass endotoxin. All subjects with biopsy-proven and suspected lung disease had antibodies directed toward the purified Cytophaga endotoxin. The data suggest that the Cytophaga endotoxin is the putative agent of lung disease in the textile facility.