Influence of Bcg Administration Time on the in-Vivo Migration of Leukocytes

The temporal variation in the migration of polymorphonuclear leukocytes (PMN) induced by live BCG was studied in the mouse. Ten μl of a 5 ± 10⁶ live BCG/ml suspension or sterile saline were placed on a cell trap immediately before its subcutaneous implantation at different clock times: 0100, 0500, 0900, 1300, 1700 and 2100 in animals synchronized with L(0700-1900): D(1900-0700). Eight hours later, the cell trap was removed, prepared for histological identification and counted. PMN counts in the cell trap were maximal 480 min after implantation. Nonspecific migration was thought to occur and the peak value of leukocytes of 22.8 ± 6.1 cells/10,000 μm² was obtained when the saline cell-trap was implanted at 0500. In the BCG-treated mice, a circadian rhythm was observed in the migration of leukocytes. The acrophase was at 1700. The results support the hypothesis that the circadian stage of antigen encounter influences the magnitude of the immune response.     

Determination of bacterial cell number and cell volume by means of flow cytometry, transmission electron microscopy, and epifluorescence microscopy

Comparative measurements of bacterial total counts and volumes of flow cytometry (FCM), transmission electron (TEM), and epifluorescence microscopy (EFM), were undertaken during a four week mesocosm experiment. Total counts of bacteria measured by TEM, EFM, and FCM were in the range of 1 · 10⁶−6 cells ml⁻¹, 1 · 10⁶−3 · 10¹⁶ cells ml⁻¹, and 5 · 10⁵ cells ml⁻¹ respectively. The mean volume of the bacterial community, measured by means of EFM and TEM, increased from 0.12–0.15 μm³ at the start of the experiment to 0.39–0.53 μm³ at the end. Generally, there was good agreement between the two methods and regression analyses gave r = 0.87 (p < < 0.01) for cell volume and r = 0.97 (p < < 0.01) for cell number. DAPI stained bacteria with volumes less than 0.2 μm³ were not detected by flow cytometry and these were generally an order of magnitude lower than counts made by TEM and EFM. For samples where the mean bacterial cell volume was longer than 0.3 μm³, all three methods were in agreement both with respect to counts and volume estimates.     

Influence of phosphorus concentration on the growth kinetics and stoichiometry of the microalga Scenedesmus obliquus

The growth of the freshwater microalga Scenedesmus obliquus was studied at 30°C in a mineral culture medium with phosphorus concentrations of between 0 and 372 μ . The values for the specific growth rates, between and , fitted a semistructured substrate-limitation model with μ_m1 = 0·0466 h⁻¹, μ_m2 = 0·0256 h⁻¹ and . The specific uptake rate of phosphorus reached a maximum value of q_Sm1 = 658·01 × 10⁻⁴ μmol P mg⁻¹ biomass h⁻¹.     

Enhanced Superoxide Production with on Change of the Antioxidant Activity in Gingival Fluid of Patients with Chronic Adult Periodontitis

In the gingival crevicular fluid (GCF) of control and chronic adult periodontitis (CAP) patients there is a spontaneous release of O₂^- radicals from polymorphonuclear leukocytes (PMN). The addition of the exogenous stimuli phorbol myrystate acetate (PMA) decreased the O₂^- formation in control GCF, while in CAP patients produced a marked enhancement of O₂^- generation.

The circulating PMN of control subjects did not show a spontaneous O₂^- formation, differently from CAP patients. On the contrary, a similar O₂^- production was measured when the circulating PMN were stimulated with PMA.

Moreover, the antioxidant activity measured in 10μl of cell free gingival supernatant (GS) of control and CAP patients had the same values by inhibiting 12.6% and 18.9% respectively of the O₂^- formation supported by a xanthine/xanthine oxidase system.

Probably, the protective or destructive effect of PMN in GCF of CAP patients depends on the variations of the rate of O₂^- formation in respect to the intrinsic antioxidant property of GS.     

Localization and quantitation of opsin and transducin mRNAs in bovine retina by in situ hybridization histochemistry

Oligodeoxynucleotide probes complementary to a portion of bovine opsin mRNA and transducin mRNA were used for in situ hybridization histochemistry. Within the retina, only photoreceptors expressed mRNAs detectable with these probes, and the majority of both mRNAs were in photoreceptor inner segments. More opsin mRNA was detected than transducin mRNA. In the inner segments 0.54 ± 0.05 copies/μm³ of opsin mRNA and 0.34 ± 0.05 copies/μm³ of transducin mRNA were detected. In the outer nuclear layer, 0.39 ± 0.06 copies/ μm³ of opsin mRNA and 0.27 ± 0.04 copies/μm³ of transducin mRNA were detected.     

Orcadian Rhythm of Trehalose in the Face Fly Musca Autumnalis De Geer

Trehalose levels were determined over two 24 hr spans in groups of face fly adults 3-4 days after emergence from the puparium. Face fly pupae were placed in rearing chambers at 27° C in a staggered light-dark regimen, LD 16:8, so that at a given clock hour, samples could be obtained at several different hours after lights on (HALO). Trehalose was determined in hemolymph collected from a puncture in the intersegmental membrane of the abdomen. Treated hemolymph samples were passed through a Bio-Rad Amino S-S disaccharide column and a Waters 410 refractive index detector was used to differentiate among sugars. The circadian acrophase derived by cosinor analysis in hemolymph trehalose (when the values were 25.49 and 26.86μg/μ¹ on the first and second days respectively) occurred at -226° (ca 15 HALO) and the bathyphase at 24 HALO. The mesor = 11.82μg/μ¹ trehalose, the amplitude = 8.57/μg/μ¹ trehalose and the P-value for presence of a rhythm was 0.003. Based on these data, differences between control and test flies in a bioassay of hypertrehalosemic activity would be most easily observed at 0-8 HALO, while exogenous hypotrehalosemic activity would be best assayed at 12-20 HALO.     

Production d'NH4 par la crevette Crangon crangon L. dans deux écosystémes côtiers. approche expérimentale et étude de l'influence du sédiment sur le taux d'excrétion

Estimation of the ammonia production of the shrimp C. crangon in two littoral ecosystems (oligotrophic sand and eutrophic mud) was determined in winter and summer conditions from laboratory observations in experimental microcosms. The ammonia excretion rate of C. crangon was not influenced by either the sediment type or the ammonia concentration of the overlying water; on the other hand, the mean excretion rate and the response to initial handling stress increased markedly as shrimp were deprived of soft substratum.

The daily ammonia production of C. crangon was 16 μmol NH₃ · g ⁻¹ wet wt · day ⁻¹ in winter and 40 μmol in summer. A gross production of 12 μmol NH₃ · m⁻² · day ⁻¹ and 300–700 μmol μ m⁻² · day⁻¹, respectively, could be expected in the two ecosystems studied. This would account for 5% (winter) and 2–4% (summer) of the total NH⁺₄ flux at the sediment-water interface. The contribution of the excretion of all macrofauna to the NH⁺₄ flux from the sediment is discussed.     

Photosynthetic response of Myriophyllum salsugineum A.E. orchard to photon irradiance, temperature and external free CO2

The photosynthetic capacity of Myriophyllum salsugineum A.E. Orchard was measured, using plants collected from Lake Wendouree, Ballarat, Victoria and grown subsequently in a glasshouse pond at Griffith, New South Wales. At pH 7.00, under conditions of constant total alkalinity of 1.0 meq dm⁻³ and saturating photon irradiance, the temperature optimum was found to be 30–35°C with rates of 140 μmol mg⁻¹ chlorophyll a h⁻¹ for oxygen production and 149 μmol mg⁻¹ chlorophyll a h⁻¹ for consumption of CO₂. These rates are generally higher than those measured by other workers for the noxious Eurasian water milfoil, Myriophyllum spicatum L., of which Myriophyllum salsugineum is a close relative. The light-compensation point and the photon irradiance required to saturate photosynthetic oxygen production were exponentially dependent on water temperature. Over the temperature range 15–35°C the light-compensation point increased from 2.4 to 16.9 μmol (PAR) m⁻² s⁻¹ for oxygen production while saturation photon irradiance increased from 41.5 to 138 μmol (PAR) m⁻² s⁻¹ for oxygen production and from 42.0 to 174 μmol (PAR) m⁻² s⁻¹ for CO₂ consumption. Respiration rates increased from 27.1 to 112.3 μmol (oxygen consumed) g⁻¹ dry weight h⁻¹ as temperature was increased from 15 to 35°C. The optimum temperature for productivity is 30°C.     

Behavioral and Neurochemical Effects of Fencamfamine on Rats: A Chronobiologic Approach

Fencamfamine (FCF) is a psychostimulant classified as an indirect dopaminergic agonist. Circadian rhythms of some behavioral and neurochemical parameters were investigated in control rats and in rats which had been treated with a single dose of FCF across the 24-hr span. Rats were entrained to light/dark (LD) 12:12, lights on from 0700 to 1900. In behavioral experiments (performed in March) the rats were injected intraperitoneally with saline or FCF (3.5 mg/kg) at one of six times: 0900, 1300, 1700, 2100, 0100 or 0500. Fifteen minutes after treatment the duration of sniffing, rearing and locomotion was recorded during 120 min. Controls showed circadian rhythms for sniffing and rearing with acrophases at 2255 and 0118, respectively. In animals treated with FCF, only locomotion displayed significant circadian variation with acrophase at 1912. Two-way analysis of variance (ANOVA) showed a statistically significant circadian time-dependent effect of FCF on all behavioral parameters studied; the increase of sniffing, rearing and locomotion induced by FCF was higher in rats treated during the rest phase. In the biochemical studies (performed between March-June), rats were treated (i.p.) with saline or FCF (10 mg/kg) at one of four times: 0900, 1700, 2100 or 0100. The levels of homovanillic acid (HVA) in the striatum and tuberculum olfactorium, 5-hydroxyindolacetic acid (5-HIAA) in the cerebellum and 3-methoxy-4-hydroxypheniglycol (MHPG) in the frontal cortex were determined. Controls showed circadian rhythms for HVA (striatum), MHPG (frontal cortex) and 5-HIAA (cerebellum) with acrophases at 2233, 1955 and 1029, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Circadian Phase Dependent Pharmacokinetics of Disopyramide in Mice

The focus of the reported work is investigation of disopyramide chronopharmacokinetics in the mouse. Different groups of male NMRI mice maintained under controlled environmental conditions (LD: 0600-1800) received a single intraperitoneal injection of disopyramide (30mg per kg of body weight) at one of four different fixed time points of a 24-h period, i.e. 1000, 1600, 2200 or 0400. Blood samples were taken 0.5,1,2,3,4 and 6 hr after drug administration and total and free plasma levels of disopyramide were measured by an immunoenzymatic method.

Our data showed statistically significant circadian rhythms in the following pharmacokinetic parameters: highest volume of distribution = 3.91 ± 0.211kg^-1 at 2200 (circadian amplitude, half the peak-to-trough difference relative to the 24-hr mean multiplied by 100, is 34%); highest area under concentration curves = 16.06 ± 1.03μgml^-1hr^-1 at 0400 (circadian amplitude = 43%) and highest clearance = 3.04 ± 0.191hr“kg”¹ at 2200 (circadian amplitude = 21%). Protein binding of the drug was shown to ^he circadian time dependent. Alpha and beta phase elimination half-lives were not found to be significantly circadian phase-dependent. Thus circadian changes in disopyramide clearance may represent circadian changes in the drug's volume of distribution.     

The response of intact Strongyloides ratti infective (L3) larvae to substrates and inhibitors of respiratory electron transport.

Live, intact third-stage larvae (L3s) of Strongyloides ratti in the absence of exogenous substrates consumed oxygen at a rate (E-QO₂) of 181.8 ± 12.4 ng atoms min⁻¹ mg dry weight⁻¹ at 35°C. Respiratory electron transport (RET) Complex I inhibitor rotenone (2 μ ) produced 33 ± 6.5% inhibition of the E-QO₂. Unusually the rotenone-induced inhibition was not relieved by 5 μ -succinate. The E-QO₂ of intact L3s was refractory to RET Complex III inhibitor antimycin A at 2 μ ; 4 μ -antimycin inhibited ≤ 10% of the E-QO₂. The electron donor couple ascorbate/TMPD augmented the E-QO₂ in the presence of rotenone (2 μ ) and antimycin A (4 μ ) by 110%. Azide (1 m ) stimulated the antimycin A refractory QO₂ by 36.6 ± 7.2% which was only partially inhibited by 1.0 m -KCN ( ). The data suggest the presence of classical (CPW) and alternate (APW) electron transport pathways in S. ratti L3s.     

Effects of peptide YY and its analogues on chloride ion secretion in fed and fasted rat jejunum

The aim of our study was to determine whether a meal modifies the antisecretory response induced by PYY and the structural requirements to elicit antisecretory effects of analogue PYY(22–36) for potential antidiarrhea therapy. The variations in short-circuit current (Isc) due to the modification of ionic transport across the rat intestine were assessed in vitro, using Ussing chambers. In fasted rats, PYY induced a dose- and time-dependent reduction in Isc, with a sensitivity threshold at 5 × 10⁻¹¹ M (ΔIsc −2 ± 0.5 μA/cm²). The reduction was maximal at 10⁻⁷ M (Isc −23 ± 2 μA/cm²), and the concentration producing half-maximal inhibition was 10⁻⁹ M. At 10⁻⁷ M, reduction of Isc by PYY reached 90% of response to 5 × 10⁻⁵ M bumetanide. The PYY effect was partly reversed by 10⁻⁵ M forskolin (Isc +13.43 ± 2.91 μA/h·cm², p < 0.05) or 10⁻³ M dibutyryl adenosine 3′,5′ cyclic monophosphate (Isc +12 ± 1.69 μA/cm², p < 0.05). Naloxone and tetrodotoxin did not alter the effect of PYY. In addition, PYY and its analogue P915 reduced net chloride ion secretion to 2.85 and 2.29 μEq/cm² (p < 0.05), respectively. The antisecretory effect of PYY was accompanied by dose- and time-dependent desensitization when jejunum was prestimulated by a lower dose of peptide. The antisecretory potencies exhibited by PYY analogues required both a C-terminal fragment (22–36) and an aromatic amino acid residue (Trp or Phe) at position 27. At 10⁻⁷ M the biological activity of PYY was lower in fed than fasted rats (p < 0.001). Our results confirm the antisecretory effect of PYY, but show that the fed period is accompanied by desensitization, similar to the transient desensitization observed in the fasted period with cumulative doses. This suggests that PYY may act as a physiological mediator that reduces intestinal secretion.     

A study in UF-membrane reactor on activity and stability of nitrile hydratase from Microbacterium imperiale CBS 498-74 resting cells for propionamide production

The bioconversion of propionitrile to propionamide was catalysed by nitrile hydratase (NHase) using resting cells of Microbacterium imperiale CBS 498-74 (formerly, Brevibacterium imperiale). This microorganism, cultivated in a shake flask, at 28 °C, presented a specific NHase activity of 34.4 U mg_DCW⁻¹ (dry cell weight). The kinetic parameters, K_m and V_max, tested in 50 mM sodium phosphate buffer, pH 7.0, in the propionitrile bioconversion was evaluated in batch reactor at 10 °C and resulted 21.6 mM and 11.04 μmol min⁻¹ mg_DCW⁻¹, respectively. The measured apparent activation energy, 25.54 kJ mol⁻¹, indicated a partial control by mass transport, more likely through the cell wall.

UF-membrane reactors were used for kinetic characterisation of the NHase catalysed reaction. The time dependence of enzyme deactivation on reaction temperature (from 5 to 25 °C), on substrate concentrations (from 100 to 800 mM), and on resting cell loading (from 1.5 to 200 μg  ml⁻¹) indicated: lower diffusional control (E_a=37.73 kJ mol⁻¹); and NHase irreversible damage caused by high substrate concentration. Finally, it is noteworthy that in an integral reactor continuously operating for 30 h, at 10 °C, 100% conversion of propionitrile (200 mM) was attained using 200 μg  ml⁻¹ of resting cells, with a maximum volumetric productivity of 0.5 g l⁻¹ h⁻¹.     

Stimulation of platelet serotonin and Rb uptake by N-ethylmaleimide

The effects of N-ethylmaleimide (NEM) on mouse platelet serotonin (5-HT) and ⁸⁶Rb⁺ uptake were studied. The 5-HT transport system showed a biphasic response to increasing concentrations of NEM, with low concentrations (25–50 μM) stimulating and high concentrations (200–400 μM) inhibiting 5-HT transport. Fluoxetine, an inhibitor of the platelet 5-HT transporter, blocked NEM-induced stimulation of 5-HT transport. The kinetics of 5-HT uptake indicated that NEM (50 μM) markedly increased the maximal rate of 5-HT transport (V_max control = 28.4±1.4 pmol/10⁸ platelets/4 min vs V_max NEM = 64.5±9.5 pmol/10⁸ platelets/4 min but had no significant effect on the K_m value. Platelet Na⁺ K⁺ ATPase activity was determined by measuring ⁸⁶Rb⁺ uptake. Platelet ⁸⁶Rb⁺ uptake showed a biphasic response to NEM, with low concentrations (25–100 μM) significantly stimulating and high concentrations (400 μM) inhibiting uptake. These changes in platelet ⁸⁶Rb⁺ uptake paralleled the biphasic changes in 5-HT transport. In the presence of fluoxetine, 5-HT transport was markedly inhibited but no change in the ability of NEM to stimulate ⁸⁶Rb⁺ uptake was observed. These data suggest that low concentrations of NEM activate plasma membrane Na⁺ K⁺ ATPase which results in a marked stimulation of platelet 5-HT transport.     

Glucocorticoids suppress vasopressin gene expression in human suprachiasmatic nucleus

Sleep impairment is one of the major side effects of glucocorticoid therapy. The mechanism responsible for this circadian disorder is unknown, but alterations in the suprachiasmatic nucleus (SCN), the biological clock of the human brain, are presumed to play a major role. In the present study, the amount of vasopressin mRNA (AVP mRNA) expression in the SCN was investigated in 10 glucocorticoid-exposed patients and 10 glucocorticoid free, age- and clock time of death-matched controls. The total amount of AVP mRNA, expressed as masked silver grains in the SCN, was two times lower in glucocorticoid-exposed patients (n = 10; 5115 ± 1314 μm²) than that in controls (n = 10; 11,021 ± 1408 μm²) (P = 0.006). There was also a 53% decrease in the total number of profiles in the SCN that expressed AVP mRNA in glucocorticoid-exposed patients (16,759 ± 3110) compared with those in controls (31,490 ± 3816) (P = 0.01). In conclusion, glucocorticoids have an inhibitory effect on AVP mRNA expression in the human SCN, which may be the biological basis of the circadian rhythm disturbances during glucocorticoid therapy.     

Temporal pattern in swimming activity of two fish species (Danio rerio and Leucaspius delineatus) under chemical stress conditions

Circadian periodicity of swimming activity was investigated in two fish species, the zebrafish (Danio rerio) and the sunbleak (Leucaspius delineatus) under sublethal long-term exposure to the cyanobacteria toxin microcystin-LR (nominal concentrations of 0.5 μg l^- 1, 5 μg l^- 1, 15 μg l^- 1, 50 μg l^- 1) in 15-litre tanks. Swimming activity of fish was monitored continuously by using an automated video-monitoring and object-tracing system over a period of 17 days. Influenced by long-term exposure to microcystin-LR, Leucaspius delineatus reversed their significant diurnal swimming activity and the fish became statistically significant nocturnal. Danio rerio remained diurnal active, but a significant phase shift was registered. In both Danio rerio and Leucaspius delineatus analysis of time series by cosinor regression revealed microcystin-LR induced dose-dependent alterations of the mean of oscillation, amplitude, acrophase and period length in a different extent. For Danio rerio the periodogram analysis revealed a significant circadian component of swimming activity for control as well as exposure groups, whereby the spectral amplitude clearly decreased at microcystin-LR concentrations of 15 and 50 μg l^- 1. For Leucaspius delineatus the amplitude of circadian rhythm was decreased at all exposure concentrations of MC-LR. Furthermore the dominance of circadian rhythm was clearly reduced, whereas the rate of ultradian rhythms increased at elevated MC-LR concentrations of 5 μg l^- 1, 15 μg l^- 1 and 50 μg l^- 1. The studied temporal aspects of behaviour clearly indicated stress symptoms in both fish species, therefore it proved to be a relevant method to characterise the impact of toxic substances in the environment and for biomonitoring.     

Galanin-induced relaxation in gastric smooth muscle cells is mediated by cyclic AMP

Galanin has numerous effects on gastrointestinal motility in different species; however, its cellular basis of action in mediating these effects is unclear. Dispersed gastric smooth muscle cells have been shown to possess high-affinity galanin receptors that increase cAMP and cause relaxation. Recent studies show some smooth muscle relaxants such as VIP cause relaxation by both cAMP-dependent and -independent mechanisms. It is unknown if galanin's cellular basis of relaxation is similar or different from that of VIP. To investigate galanin's relaxant effect and compare it to VIP's effect, dispersed smooth muscle cells from guinea pig stomach were prepared by collagenase digestion. The mean length in resting cells was 110 ± 2 μm and, with carbachol treatment, contracted to 89 ± 2 μm. VIP and galanin alone had no effect on cell length, but each caused a dose-dependent inhibition of carbachol-induced contraction and both had an EC₅₀ of 3–7 nM. Galanin (1 μM) and VIP (1 μM) increased cellular cAMP from 118 ± 10 pmol/10⁶ cells in control to 212 ± 14 and 214 ± 12 pmol/10⁶ cells, respectively. The protein kinase A inhibitor, Rp-cAMPS, at 100 μM, completely inhibited the relaxant effect of an EC₅₀ concentration of galanin (3 nM), but only inhibited that by VIP by 80% (p < 0.05). Adding the nitric oxide inhibitor, -NNA ( ), at 100 μM did not alter the length of resting cells or inhibit carbachol-induced contraction. However, -NNA (100 μM) decreased VIP-induced relaxation by 45%, whereas it had no effect on galanin-induced relaxation. To determine the ability of each peptide to activate nitric oxide, the incorporation of [³H]arginine into [³H]citrulline was determined. Galanin (1 μM) did not cause nitric oxide generation whereas VIP (1 μM) increased nitric oxide generation above the control by 97 ± 14% (p < 0.01). These results demonstrated that with galanin, in contrast to VIP, nitric oxide is not involved in its ability to cause gastric smooth muscle cell relaxation. The relaxant action of galanin can be accounted for completely by its ability to activate protein kinase A and therefore resembles recent results with β-adrenergic agents.     

Characterization of growth hormone-releasing hormone (GHRH) binding to cloned porcine GHRH receptor

To study structure-activity relationships of growth hormone-releasing hormone (GHRH), a competitive binding assay was developed using cloned porcine adenopituitary GHRH receptors expressed in human kidney 293 cells. Specific binding of [His¹,¹²⁵I-Tyr¹⁰,Nle²⁷]hGHRH(1–32)-NH₂ increased linearly with protein concentration (10–45 μg protein/tube). Binding reached equilibrium after 90 min at 30°C and remained constant for at least 240 min. Binding was reversible to one class of high-affinity sites (K_d = 1.04 ± 0.19 nM, B_max = 3.9 ± 0.53 pmol/mg protein). Binding was selective with a rank order of affinity (IC₅₀) for porcine GHRH (2.8 ± 0.51 nM), rat GHRH (3.1 ± 0.69 nM), [N-Ac-Tyr¹, -Arg²]hGHRH(3–29)-NH₂ (3.9 ± 0.58 nM), and [ -Thr⁷]GHRH(1–29)-NH₂ (189.7 ± 14.3 nM), consistent with their binding to a GHRH receptor. Nonhydrolyzable guanine nucleotides inhibited binding. These data describe a selective and reliable method for a competitive GHRH binding assay that for the first time utilizes rapid filtration to terminate the binding assay.     

Nutrient removal by thermophilic Fischerella (Mastigocladus laminosus) in a simulated algaculture process

A novel nutrient removal/waste heat utilization process was simulated using semicontinuous cultures of the thermophilic cyanobacterium Fischerella. Dissolved inorganic carbon (DIC)-enriched cultures, maintained with 10 mg l⁻¹ daily productivity, diurnally varying temperature (from 55°C to 26–28°C), a 12:12 light cycle (200 μE sec⁻¹ m⁻²) and 50% biomass recycling into heated effluent at the beginning of each light period, removed > 95% of NO₃⁻ + NO₂⁻−N, 71% of NH₃-N, 82% of PO₄³⁻ −P, and 70% of total P from effluent water samples containing approximately 400 μg l⁻¹ combined N and 60 μg l⁻¹ P. Nutrient removal was not severely impaired by an altered temperature gradient, doubled light intensity, or DIC limitation. Recycling 75% of the biomass at the end of each light period resulted in unimpaired NO₃⁻ + NO₂⁻ removal, 38–45% P removal and no net NH₃ removal. Diurnally varying P removal, averaging 50–60%, and nearly constant > 80% N removal, are therefore projected for a full-scale process with continuous biomass recycling.     

Characterization of proctolin binding sites on locust oviduct membranes

The binding of [³H]proctolin to oviduct membranes has been analyzed to investigate the nature of proctolin binding sites in the oviduct. Proctolin binding was found to be time dependent, proportional to concentration of membrane protein, saturable, specific and reversible. Two apparent proctolin binding sites were recognized. The first had a K_d of 400 ± 82 nM and a B_max of 23.7 ± 6.7 pmol/mg protein. The second had a K_d of 2.4 ± 0.2 μM and a B_max of 96.3 ± 16.7 pmo/mg protein.

Binding was specific in thatcompetition experiments with a wide range of peptides showed that only Arg-Tyr-Leu-Pro-Ala was an effective competitor at μM concentrations. All other peptides examined weekly reduced proctolin binding at concentrations above 50 μM. Certain peptides were found to potentiate [³]pproctolin binding at low μM concentrations (1–10 μM) and to inhibit proctolin binding at higher concentrations. The significance of these findings is discussed.