Sea-Ice Bacteria Halomonas sp. Strain 363 and Paracoccus sp. Strain 392 Produce Multiple Types of Poly-3-Hydroxyalkaonoic Acid (PHA) Storage Polymers at Low Temperature.

Poly-3-hydroxyalkanoic acids (PHAs) are bacterial storage polymers commonly used in bioplastic production. Halophilic bacteria are industrially interesting organisms, as their salinity tolerance and psychrophilic nature lowers sterility requirements and subsequent production costs. We investigated PHA synthesis in two bacterial strains, Halomonas sp. 363 and Paracoccus sp. 392, isolated from Southern Ocean sea ice and elucidated the related PHA biopolymer accumulation and composition with various approaches, such as transcriptomics, microscopy, and chromatography. We show that both bacterial strains produce PHAs at 4°C when the availability of nitrogen and/or oxygen limited growth. The genome of Halomonas sp. 363 carries three phaC synthase genes and transcribes genes along three PHA pathways (I to III), whereas Paracoccus sp. 392 carries only one phaC gene and transcribes genes along one pathway (I). Thus, Halomonas sp. 363 has a versatile repertoire of phaC genes and pathways enabling production of both short- and medium-chain-length PHA products. IMPORTANCE Plastic pollution is one of the most topical threats to the health of the oceans and seas. One recognized way to alleviate the problem is to use degradable bioplastic materials in high-risk applications. PHA is a promising bioplastic material as it is nontoxic and fully produced and degraded by bacteria. Sea ice is an interesting environment for prospecting novel PHA-producing organisms, since traits advantageous to lower production costs, such as tolerance for high salinities and low temperatures, are common. We show that two sea-ice bacteria, Halomonas sp. 363 and Paracoccus sp. 392, are able to produce various types of PHA from inexpensive carbon sources. Halomonas sp. 363 is an especially interesting PHA-producing organism, since it has three different synthesis pathways to produce both short- and medium-chain-length PHAs.

Growth and nitrogen uptake by Salicornia europaea and Aster tripolium in nutrient conditions typical of aquaculture wastewater.

The increasing need for environmentally sound aquaculture development can, in part, be addressed by using halophytic plants in integrated multitrophic aquaculture systems (IMTA) to remove waste dissolved nitrogen (N). However, knowledge of plant ability to take up nitrogen is of foremost importance to predict plants performance in such systems. Two species, Salicornia europaea and Aster tripolium, have been identified as potential candidates for IMTA due to their salt tolerance, potential N removal capabilities and their high commercial value as an additional crop. This study investigated the growth and N uptake rates of these two species under different N supply (NH4(+), NO3(-), NH4NO3). S. europaea plants produced a lower biomass when grown in NH4(+) compared to NO3(-) or NH4NO3, while A. tripolium biomass was not affected by the form in which N was supplied. N uptake in plants incubated at different concentrations of (15)N enriched solution (up to 2 mmol l(-1)) fitted the Michaelis-Menten model. While S. europaea NH4-N maximum uptake did not differ between starved and non-starved plants, A. tripolium NH4-N uptake was higher in starved plants when supplied alone. When NO3(-) was supplied alone, NO3-N maximum uptake was lower, for both species, when the plants were not starved. Comparison of starved and non-starved plants N uptake demonstrates the need for cautious interpretation of N uptake rates across different conditions. According to the observed results, both S. europaea and A. tripolium are capable of significantly high biomass production and N removal making them potential species for inclusion in efficient IMTA.

Health communication cards as a tool for behaviour change.

Individuals seeking healthcare treatment in the context of obesity often experience difficulty engaging in discussions around their health and face challenges finding consensus with practitioners on care plans that best suit their lives. The complex set of biological, social, and environmental variables that have contributed to the higher prevalence of obesity are well illustrated in the foresight obesity system map. Effectively understanding and addressing key variables for each individual has proven to be difficult, with clinicians facing barriers and limited resources to help address patients' unique needs. However, productive discussions inspired by patient centered care may be particularly effective in promoting behaviour change. Tools based on systems science that facilitate patient centered care and help identify behaviour change priorities have not been developed to help treat adult obesity. This project created and pilot tested a card based clinical communication tool designed to help facilitate conversations with individuals engaged in health behaviour change. The health communication cards were designed to help direct conversation between patients and healthcare providers toward issues relevant to the individual. Use of the cards to facilitate patient driven conversations in clinical care may help to streamline conversations, set realistic care plan goals, and improve long term rates of compliance.

Halophyte filter beds for treatment of saline wastewater from aquaculture.

The expansion of aquaculture and the recent development of more intensive land-based marine farms require efficient and cost-effective systems for treatment of highly nutrient-rich saline wastewater. Constructed wetlands with halophytic plants offer the potential for waste-stream treatment combined with production of valuable secondary plant crops. Pilot wetland filter beds, constructed in triplicate and planted with the saltmarsh plant Salicornia europaea, were evaluated over 88 days under commercial operating conditions on a marine fish and shrimp farm. Nitrogen waste was primarily in the form of dissolved inorganic nitrogen (TDIN) and was removed by 98.2 ± 2.2% under ambient loadings of 109-383 µmol l(-1). There was a linear relationship between TDIN uptake and loading over the range of inputs tested. At peak loadings of up to 8185 ± 590 µmol l(-1) (equivalent to 600 mmol N m(-2) d(-1)), the filter beds removed between 30 and 58% (250 mmol N m(-2) d(-1)) of influent TDIN. Influent dissolved inorganic phosphorus levels ranged from 34 to 90 µmol l(-1), with 36-89% reduction under routine operations. Dissolved organic nitrogen (DON) loadings were lower (11-144 µmol l(-1)), and between 23 and 69% of influent DON was removed during routine operation, with no significant removal of DON under high TDIN loading. Over the 88-day study, cumulative nitrogen removal was 1.28 mol m(-2), of which 1.09 mol m(-2) was retained in plant tissue, with plant uptake ranging from 2.4 to 27.0 mmol N g(-1) dry weight d(-1). The results demonstrate the effectiveness of N and P removal from wastewater from land-based intensive marine aquaculture farms by constructed wetlands planted with S. europaea.

Antarctic Sea ice--a habitat for extremophiles.

The pack ice of Earth's polar oceans appears to be frozen white desert, devoid of life. However, beneath the snow lies a unique habitat for a group of bacteria and microscopic plants and animals that are encased in an ice matrix at low temperatures and light levels, with the only liquid being pockets of concentrated brines. Survival in these conditions requires a complex suite of physiological and metabolic adaptations, but sea-ice organisms thrive in the ice, and their prolific growth ensures they play a fundamental role in polar ecosystems. Apart from their ecological importance, the bacterial and algae species found in sea ice have become the focus for novel biotechnology, as well as being considered proxies for possible life forms on ice-covered extraterrestrial bodies.

Different neural mechanisms underlie dizocilpine maleate- and dopamine agonist-induced locomotor activity.

This study evaluated and compared the role of mesoaccumbens dopamine and the ventral pallidal region in the locomotor stimulatory action of the non-competitive N-methyl-D-aspartate antagonist dizocilpine maleate and dopamine agonists. Intra-accumbens injections of both amphetamine (1, 5 and 25 nmol) and dizocilpine maleate (1, 5, 25 and 50 nmol) induced a dose-dependent increase in locomotor activity. The N-methyl-D-aspartate antagonist was somewhat less effective than amphetamine. 6-Hydroxydopamine dopamine-depleting lesions of the nucleus accumbens completely blocked locomotor stimulation induced by focal administrations of amphetamine (5 nmol), but were ineffective in altering the actions of dizocilpine maleate (50 nmol). Ibotenic acid lesions of the ventral pallidal region and muscimol injections into this area also prevented the stimulatory effects of systemic amphetamine (1 mg/kg), while having no effect on the locomotor-activating actions of systemic dizocilpine maleate (0.3 mg/kg). Microdialysis studies revealed that systemically administered apomorphine (2 mg/kg) significantly decreased extracellular GABA in the pallidum, which was accompanied by substantial increases in locomotor output. Systemically administered dizocilpine maleate (0.3 mg/kg), on the other hand, also increased locomotor activity without having any effect on pallidal GABA. These data, taken together, indicate that while the locomotor effects of dopamine agonists are dependent upon intact mesoaccumbens dopamine and involve GABAergic efferents from the nucleus accumbens to the ventral pallidum, dizocilpine maleate's stimulatory actions are independent of such mechanisms.

Sertraline, a selective serotonin reuptake inhibitor modulates extracellular noradrenaline in the rat frontal cortex.

The selective action of selective serotonergic reuptake inhibitors (SSRIs) on 5-hydroxytryptamine (5-HT) neurotransmission underlies the therapeutic effectiveness of this class of drugs. Yet there is increasing evidence that changes in extracellular 5-HT content may result in changes in the regulation of other neurotransmitter systems. The present study examines the effects of acute and chronic administration of the SSRI sertraline on release of endogenous noradrenaline (NA) in the frontal cortex and hippocampus of the rat using in vivo microdialysis. Acute administration of sertraline did not significantly alter NA release in either the cortex or the hippocampus. However, 24 h after chronic (14 days) administration of the drug (10 mg/kg i.p. once daily), NA release in the cortex but not hippocampus was significantly enhanced. The lack of an effect on NA release following a challenge with the alpha2-antagonist idazoxan suggests that chronic drug treatment has reduced the sensitivity of cortical pre-synaptic alpha2-adrenoceptors, activation of which would normally inhibit further NA release. The possible mechanisms underlying the regional specificity of the effect of chronic and not acute sertraline administration and the implications of these results for our understanding of depression are discussed.

Regionally specific changes in extracellular noradrenaline following chronic idazoxan as revealed by in vivo microdialysis.

The selective alpha 2-adrenoceptor antagonist idazoxan was administered chronically (0.8 mg/kg per h) to rats for a period of 10 days via osmotic minipumps. On day 11, 24 h after removal of the pumps, the rats were anaesthetised and microdialysis probes were implanted into either the frontal cortex or hippocampus. Basal noradrenaline release in the frontal cortex was significantly elevated compared with the saline control group. Each animal was then challenged with idazoxan (10 mg/kg s.c.). Inhibition of presynaptic alpha 2-adrenoceptors resulted in a significant increase in noradrenaline release in the saline control group. However, animals treated chronically with idazoxan, showed a markedly attenuated response to the single dose idazoxan challenge in the frontal cortex. No significant change in either basal release or in response to idazoxan challenge was observed in the hippocampus in the chronic idazoxan-treated animals as compared with the chronic saline control group. Chronic idazoxan administration results in selective enhancement of noradrenaline release in the frontal cortex but not in the hippocampus. This would be consistent with a down-regulation of presynaptic alpha 2-adrenoceptors with the subsequent loss of presynaptic noradrenergic negative feedback inhibition.

Focal and systemic cocaine differentially affect extracellular norepinephrine in the locus coeruleus, frontal cortex and hippocampus of the anaesthetized rat.

The purpose of this study was to characterize and compare the effects of cocaine on norepinephrine (NE) overflow in the forebrain and somatodendritic regions of anaesthetized rats with microdialysis. Intraperitoneal injections of cocaine (20 mg/kg) failed to increase NE overflow in the hippocampus and the frontal cortex but did elevate NE in the region of the locus coeruleus. Focal application of cocaine (1-100 microM) via the dialysis probe into the region of the locus coeruleus also produced a concentration dependent elevation of extracellular NE. In the terminal regions the application of focal cocaine (1-100 microM) showed a differential effect, with a concentration dependent increase in extracellular NE in the hippocampus, whilst in the frontal cortex only the highest concentration of cocaine (100 microM) elevated extracellular NE. The regional differences seen following focal applications in this study may be related to differences in transporter function in the three brain areas or to differences in the affinity for cocaine. The inability of systematically administered cocaine to increase hippocampal and cortical NE is probably related to its predominant actions in the somatodendritic region.

RTI-4793-14, a new ligand with high affinity and selectivity for the (+)-MK801-insensitive [3H]1-]1-(2-thienyl)cyclohexyl]piperidine binding site (PCP site 2) of guinea pig brain.

[3H]TCP, an analog of the dissociative anesthetic phencyclidine (PCP), binds with high affinity to two sites in guinea pig brain membranes, one that is MK-801 sensitive and one that is not. The MK-801-sensitive site (PCP site 1) is associated with NMDA receptors, whereas the MK-801-insensitive site (PCP site 2) may be associated with biogenic amine transporters (BAT). Although several "BAT ligands" are known that bind selectively to PCP site 2 and not to PCP site 1 (such as indatraline), these compounds have low affinity for site 2 (Ki values > 1 microM). Here we demonstrate that the novel pyrrole RTI-4793-14 is a selective, high affinity ligand for PCP site 2. We determined the IC50 values of RTI-4793-14 and several reference compounds [PCP, (+)-MK801 and indatraline] for PCP site 1 (assayed with [3H](+)-MK801), PCP site 2 (assayed with [3H]TCP in the presence of 500 nM (+)-MK801) and a variety of BAT-related measures ([3H]CFT binding to the DA transporter, [3H]nisoxetine binding to the norepinephrine transporter, [3H]dopamine uptake, [3H]serotonin uptake). In addition, we determined the ability of RTI-4793-14 to block NMDA responses in cultured hippocampal neurons under voltage clamp. (+)-MK801 had high affinity for PCP site 1 (4.6 nM) and potently inhibited NMDA-induced responses, but was much less potent in the BAT-related measures (IC50 s > 10 microM). PCP had high affinity at PCP site 1 (IC50 = 92 nM) and PCP site 2 (IC50 = 117 nM), and was moderately potent in all BAT-related measures except [3H]nisoxetine binding.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of acute and chronic electroconvulsive shock on noradrenaline release in the rat hippocampus and frontal cortex.

1. Changes in the extracellular content of endogenous noradrenaline (NA) in frontal cortex and hippocampus were determined by in vivo microdialysis following acute and chronic electroconvulsive shock (ECS) in rats anaesthetized with chloral hydrate. 2. Basal release of NA in the frontal cortex (4.9 +/- 0.3 pg/sample) did not differ significantly from that in the hippocampus (4.6 +/- 0.2 pg/sample). 3. A single ECS resulted in an increase of NA release in the hippocampus (21.1 +/- 1.3 pg/sample) and in the frontal cortex (11.6 +/- 1.2 pg/sample). In both brain regions extracellular NA had returned to basal values within 30 min. 4. Animals were treated chronically with ECS (once per day for seven days). Twenty-four h later (day 8), basal release of NA into dialysis samples from the frontal cortex was significantly increased (50%) as compared to chronic sham controls. Basal release in the hippocampus was not significantly different from the sham controls. In the chronic ECS animals the increase in NA released in both brain areas following an ECS on day 8 did not differ from either the chronic sham controls or from animals given acute ECS. 5. Animals were challenged 24 h after eight ECS or sham control treatments (once per day) with the alpha 2-adrenoceptor antagonist, idazoxan (10 mg kg-1, s.c.). Idazoxan increased NA release in the hippocampus in both groups. There was no difference in the magnitude of the response in ECS- and in sham-treated rats.In the frontal cortex, idazoxan increased the extracellular NA content in the chronic sham controls, but the response to idazoxan was significantly attenuated in the chronic ECS animals.6. Chronic but not acute ECS was found to elicit a sustained (>24 h) increase in the release of NA in the frontal cortex, but not in the hippocampus. The idazoxan data suggest that the increase may be due to a downregulation of presynaptic alpha2-adrenoceptors in the frontal cortex. The difference in response of these two brain regions to chronic ECS is discussed in terms of differences in the regulation of extracellular NA content by uptake and autoreceptor activation.

A microdialysis study of the regulation of endogenous noradrenaline release in the rat hippocampus.

In vivo microdialysis was used to investigate the regulation of noradrenaline release in rat hippocampus. Idazoxan, an alpha 2-adrenoreceptor antagonist (1-10 mg/kg), increased noradrenaline release in a dose-dependent manner. Inhibition of noradrenaline uptake by desipramine (0.05-20 microM; via the probe) also increased the extracellular content of the transmitter. In the presence of this increased noradrenaline content (desipramine via the probe), the effect of a low dose of idazoxan (1 mg/kg) was potentiated. Local perfusion of idazoxan (1-500 microM) in the hippocampus also increased noradrenaline release but not to the same extent as following systemic administration. In the presence of desipramine, unlike the systemic injection of idazoxan, local perfusion did not potentiate noradrenaline release. The data are consistent with the regulation of extracellular noradrenaline content in the hippocampus by neuronal uptake and to a lesser extent by presynaptic autoreceptors.

The effects of pH on amphetamine-induced dopamine release as measured by in vivo dialysis.

The release of endogenous dopamine (DA) from the rat corpus striatum before and after the administration of d-amphetamine sulphate (AMPH) was monitored by in vivo dialysis to compare the effects of perfusion media at pH 6.0 and at pH 7.4. Basal release of DA did not differ significantly at pH 6.0 (61.25 +/- 5.34 pg/sample, n = 4) or pH 7.4 (58.02 +/- 14.17 pg/sample, n = 4). The basal value of homovanillic acid (HVA) was not significantly reduced at pH 7.4 as compared with pH 6.0; while there was a significant reduction in 3,4-dihydroxyphenylacetic acid (DOPAC) at pH 7.4 as compared to pH 6.0. Intraperitoneal injection of 2.5 mg/kg AMPH resulted in a 21 fold increase in the concentration of DA appearing in subsequent dialysis samples. This increase in DA release was not significantly affected by the pH. Equally the decrease in DOPAC and HVA content following AMPH were also not altered by the pH. These present results differ from experiments using push-pull cannulae and suggest that responses observed with the two techniques may not be equivalent.

Angiotensin converting enzyme inhibitors produced by Streptomyces chromofuscus. Discovery, taxonomy and fermentation.

Culture A58365.1, NRRL 15098, identified as a new strain of Streptomyces chromofuscus, was found to produce two novel angiotensin converting enzyme (ACE) inhibitors, A58365A and A58365B. Fermentation medium studies afforded an increase in ACE inhibitor titers from less than 1 microgram/ml to greater than 20 micrograms/ml. Proline was the obligatory supplement for ACE inhibitor biosynthesis.

New azasteroidal antifungal antibotics from Geotrichum flavo-brunneum. I. Discovery and fermentation studies.

Although Geotrichum species occur ubiquitously, antibiotic production by members of this genus has not previously been reported. The antibiotic complex designated A25822, consisting of one major and six minor structurally-related components active primarily against Candida and Trichophyton, represents a new family of naturally-occurring compounds. Approximately 90% of the antibiotic activity synthesized remained associated with the fungal cell mass, from which it was recovered by multiple methanolic extractions for quantitation. Antibiotic production was enhanced by tryptophan, iron, zinc, and high levels of dextrin.