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Objectives: To investigate potential sleep inequities between the infants of Māori and non-Māori mothers in Aotearoa New Zealand, identify socio-ecological factors associated with infant sleep, and determine features of infant sleep that contribute to a mother-perceived infant sleep problem., Design: Secondary analysis of longitudinal data from the Moe Kura: Mother and Child, Sleep and Well-being in Aotearoa New Zealand study when infants were approximately 12 weeks old., Participants: 383 Māori and 702 non-Māori mother-infant dyads., Methods: Chi-square and independent t-tests measured bivariate associations between maternal ethnicity and infant sleep characteristics. Multivariable and ordinal logistic regression models assessed the relative impact of different socio-ecological factors on infant sleep outcome variables., Results: Key developmental markers of infant sleep did not differ by maternal ethnicity. There were some ethnicity-based differences in sleep location. Maternal ethnicity, maternal age, parity, maternal depression, maternal relationship status, life stress, breastfeeding, work status, and bedsharing were related to different dimensions of infant sleep, and to maternal perceptions of a sleep problem., Conclusion: Sleep at 12weeks is highly variable between infants and is associated with numerous socio-ecological factors. Findings support a social determinants explanation for sleep health inequities seen later in childhood., Competing Interests: Declaration of conflicts of interest No potential conflict of interest was reported by the author(s)., (Copyright © 2025 The Authors. Published by Elsevier Inc. All rights reserved.)

Study Objectives: (1) To describe sleep in infancy and early childhood among children born to mothers with and without clinically significant depressive symptoms, and (2) to explore the relationships between maternal depressive symptoms and sleep patterns and problems during infancy and early childhood., Methods: Secondary analysis of longitudinal data from the Moe Kura: Mother and Child, Sleep and Wellbeing in Aotearoa/New Zealand study. Data was collected in pregnancy (T1), 12 weeks postpartum (T2), and 3 years post-birth (T3). Participants were 262 Māori and 594 non-Māori mother-child dyads. Chi-square and Independent T-tests measured bivariate associations between maternal mood (T1, T2, T3) and child sleep characteristics (T2, T3). Binary logistic regression models examined longitudinal and concurrent associations between maternal depressive symptoms and infant and preschooler sleep. Adjusted models accounted for key socio-demographic variables, as well as infant sleep variables in preschooler models., Results: Bivariate associations were found between prior and concurrent depressive symptomology and many of the infant and preschooler sleep outcomes. In adjusted models, prenatal depressive symptoms remained independently associated with shorter-than-recommended sleep durations in preschoolers. In these models, concurrent depression was also associated with night waking, night LSRSP, and perceived sleep problems at 12 weeks postpartum, and CSHQ-determined and perceived sleep problems at 3 years post birth., Conclusions: Longitudinal and cross-sectional associations were found between maternal depressive symptoms and child sleep. Sleep appears to be one pathway by which maternal depression confers risk for suboptimal child health outcomes. Findings support the need for earlier and better maternal mental health services., (© The Author(s) 2024. Published by Oxford University Press on behalf of Sleep Research Society.)

Moe Kura is a longitudinal study focused on the role of sleep in the health and well-being of mothers and children in Aotearoa New Zealand (NZ). The leadership, design and conduct of the study is informed by Kaupapa Māori research principles and is positioned within a broader rights-based approach to health, recognising that inequities in health must be identified and understood to improve the health of wāhine Māori and tamariki. In late pregnancy 418 Māori women and 768 non-Māori women were recruited and data collected at four waves (35-37 weeks gestation, 4-6 weeks postpartum, 11-13 weeks postpartum and when the Moe Kura child was 3-4 years of age) with linkage to birth records and national administrative datasets and associated qualitative research. Findings demonstrate substantial inequities in sleep health, infant and maternal health, and maternal employment between Māori and non-Māori, along with the important role of sleep in perinatal health and maternal mental health outcomes. The research philosophy that underpins the study, the primary focus on women, and the detailed measurement of sleep during the childbearing years has provided new and important findings that contribute to intervention development and health policy for women and children in NZ., Competing Interests: No potential conflict of interest was reported by the author(s)., (© 2022 The Royal Society of New Zealand.)

Study Objectives: This study tested the acceptability and efficacy of a perinatally delivered behavioral-educational sleep intervention., Methods: Participants were 40 primiparous women assigned in late pregnancy to either an intervention (n = 20) or control (n = 20) group. The sleep intervention group (SIG) received prenatal anticipatory education and guidance regarding their own and their infant's sleep during the first 3 months postpartum. This was reinforced during phone calls within the first 6 weeks postpartum. The control group (CG) received brief sleep hygiene information at a prenatal session, followed by 2 phone calls during the same period. Mother-infant pairs wore actigraphs for 48 hours at 6 and 12 weeks postpartum, and mothers kept sleep diaries. Questionnaires completed in late pregnancy and 6 and 12 weeks postpartum related to sleep, newborn care, and mood. The main outcome measures included maternal sleep quantity, efficiency, and self-reported quality and infant sleep duration and consolidation., Results: Mothers reported high acceptability of the study processes. Sleep duration and quality increased for mothers and infants across time in both groups, with a significantly greater increase in nocturnal sleep duration for mothers in the SIG., Conclusions: Prenatal sleep guidance and postnatal follow-up seems to enhance nocturnal sleep of mothers, change their perceptions of their own sleep, and increase confidence in managing their infant's sleep. Follow-up at later intervals and replication with larger, more diverse samples may reveal further differences., (© 2020 American Academy of Sleep Medicine.)

Purpose: To quantify the monetary and time costs associated with oral contrast administration in the emergency department (ED) for patients with nontraumatic abdominal pain and to evaluate the cost savings associated with an institutional policy change in the criteria for oral contrast administration., Methods: A HIPAA-complaint, institutional review board-approved time-driven activity-based costing analysis was performed using both prospective time studies and retrospective data obtained from a quaternary care center. Retrospective data spanned a 1-year period (January 1, 2016, to December 31, 2016). A process map was generated. Examination volume-related data, labor costs, and material costs were determined and applied to a base-case model. Univariate and multivariate sensitivity analyses were conducted. Multivariate analysis was used to estimate the cost savings associated with a policy change eliminating oral contrast for patients with body mass index ≥ 25 kg/m 2 , no prior abdominal surgery within 30 days preceding CT, and no inflammatory bowel disease., Results: The baseline oral contrast utilization rate was 86% (4,541 of 5,263). The annual base-case cost estimate for oral contrast administration was $82,552. In multivariate analyses, this ranged from $13,685 to $315,393. The model was most sensitive to the volume of CTs requiring oral contrast. Applying parameters from the new policy change reduced the annual cost by 52% (cost saving: $35,836.57). Impact of oral contrast on time to discharge was highly variable and dependent on the contrast agent utilized., Conclusion: Costs associated with oral contrast in the ED are modest and should be balanced with its potential diagnostic benefits. Our criteria reduced oral contrast utilization by 52%., (Copyright © 2018 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

Immune mediators associated with human tuberculosis (TB) remain poorly defined. This study quantified levels of lung immune mediator gene expression at the time of diagnosis and during anti-TB treatment using cells obtained by induced sputum. Upon comparison to patients with other infectious lung diseases and volunteers, active pulmonary TB cases expressed significantly higher levels of mediators that counteract Th1-type and innate immunity. Despite the concomitant heightened levels of Th1-type mediators, immune activation may be rendered ineffectual by high levels of intracellular (SOCS and IRAK-M) and extracellular (IL-10 and TGF-betaRII, IL-1Rn, and IDO) immune suppressive mediators. These modulators are a direct response to Mycobacterium tuberculosis as, by day 30 of anti-TB treatment, many suppressive factors declined to that of controls whereas most Th1-type and innate immune mediators rose above pretreatment levels. Challenge of human immune cells with M. tuberculosis in vitro up-regulated these immune modulators as well. The observed low levels of NO synthase-2 produced by alveolar macrophages at TB diagnosis, along with the heightened amounts of suppressive mediators, support the conclusion that M. tuberculosis actively promotes down-modulatory mediators to counteract Th1-type and innate immunity as an immunopathological strategy. Our data highlight the potential application of immune mediators as surrogate markers for TB diagnosis or treatment response.

1. The plasma concentration, main route of metabolism and excretion of 3H-L-659,989 were studied in male and female rhesus monkeys by dosing either i.v. or orally at 10 mg/kg. 2. The percentage of the AUC for the plasma radioactivity concentration-time curve of oral vs i.v. dosed monkeys was 78% for males and 90% for females, indicating that the dose was well absorbed. 3. The bioavailability of the drug was low (less than or equal to 10%) for all monkeys, probably due to rapid first pass metabolism. The drug was metabolized-predominantly at the C-4'-propoxy side-chain. The two major plasma metabolites were identified as the 4'-2-(hydroxy)propoxy metabolite (3H-trans-4'-HP) and the 4'-hydroxy metabolite (3H-4'-hydroxy) which was isolated as a 2:1 mixture of (+/-)trans: (+/-)cis. 4. Approx. 80% of the radiolabelled dose was excreted equally in the urine and faeces in 96 h, with the largest percentage of the tritiated dose (31 +/- 4%) in the 0-24 h urine. 5. The major metabolites in the excreta were the (+/-)trans/(+/-)cis mixture of 3H-4'-hydroxy and the glucuronide conjugate of 3H-trans-4'-hydroxy. The glucuronide conjugate of 3H-trans-4'-hydroxy was excreted in the urine of i.v. and orally dosed monkeys and represented an average of 21% and 5.1% of the dose, respectively. 3H-4'-Hydroxy was excreted in both the urine and faeces, accounting for less than or equal to 0.1% and 7.4% of the dose in i.v. and orally dosed monkeys, respectively.

Dividing pairs or single cells of the large dinoflagellate, Pyrocystis fusiformis Murray, were isolated in capillary tubes and their morphology was observed over a number of days, either in a light-dark cycle or in constant darkness. Morphological stages were correlated with the first growth stage, G(1), DNA synthesis, S, the second growth stage, G(2), mitosis, M, and cytokinesis, C, segments of the cell division cycle. The S phase was identified by measuring the nuclear DNA content of cells of different morphologies by the fluorescence of 4', 6-diamidino-2-phenylindole dichloride.Cells changed from one morphological stage to the next only during the night phase of the circadian cycle, both under light-dark conditions and in continuous darkness. Cells in all segments of the cell division cycle displayed a circadian rhythm in bioluminescence. These findings are incompatible with a mechanism for circadian oscillations that invokes cycling in G(q), an hypothesized side loop from G(1). All morphological stages, not only division, appear to be phased by the circadian clock.

Cultures of Gonyaulax polyedra Stein maintained in the laboratory for 15 to 20 years, including an axenic strain isolated in 1960, have gradually lost the ability to survive in darkness. G. polyedra (70A), isolated in 1970 and maintained in a 12:12 light:dark cycle, now tolerates continuous darkness for a much shorter time than a strain isolated in 1981. I have compared the properties of strain 70A with those of this newer strain (81N), to investigate changes in Gonyaulax with length of time in culture, which may account for poor survival in darkness. When grown in continuous light (13, 12, or 4.5 watts per square meter), strains 70A and 81N have similar growth rates, yields, cell diameters, protein contents, C/N ratios, respiration rates, pigment complements, and photosynthetic rates. When entrained by a light:dark cycle (12L:12D), 70A showed no photosynthesis rhythm, although such a rhythm was formerly present. However, the circadian rhythms in bioluminescence and cell division were normal in both strains. Thus, the circadian clock is apparently still intact in 70A as in 81N. The rate of photosynthesis in strain 70A was constant at a low level, the consequent smaller accumulation of photosynthetic products probably accounting for the limited survival in darkness. The defect in strain 70A may be the loss of a component either directly affecting P(max) or necessary for transduction from the circadian clock to photosynthesis.

Intramembrane faces were visualized in the marine dinoflagellate Gonyaulax polyedra by the freeze-fracture technique, in order to test a prediction of a membrane model for circadian oscillations--i.e;, that membrane particle distribution and size change with time in the circadian cycle. Cells from each of four cell suspensions in continuous light (500 1x, 20-21 degrees C) were frozen, without fixation or cryoprotection, at four circadian times in a cycle. This paper reports findings concerning the membranes associated with the theca, particularly the cytoplasmic membrane and the membrane of the large peripheral vesicle. While the number and size distribution of the particles of the PF face of the cytoplasmic membrane were constant with time, those of the EF face of the peripheral vesicle doubled in number at 18 h circadian time as compared with 06 h. Particles of the 120-A size class, in particular, were more numerous at 12 and 18 h circadian time than at 00 and 06 h. While the finding does not provide definitive confirmation of the membrane hypothesis for circadian rhythms, it is consistent with this model. It is suggested that the peripheral vesicle may be the site of bioluminescence in Gonyaulax.

Cycloheximide, an inhibitor of protein synthesis on cytoplasmic ribosomes in eukaryotes, is shown to shift the phase of the circadian rhythm in stimulated bioluminescence in the marine dinoflagellate Gonyaulax polyedra. Kinetic analysis of the phase changes shows that this effect may be subdivided into two distinctly different and well-separated parts. The first (early) phase change occurs with 15-min exposure to cycloheximide and is saturated at low concentrations ( approximately 10 nM). The second (late) phase changes requires about 150 min of exposure to cycloheximide and is saturated at 0.36 muM cycloheximide. Twenty-times-higher concentrations cause no further phase changes. The magnitudes of both early and late phase changes depend on the time of day when the cells are exposed to cycloheximide. Early phase changes vary from 5 hr advance at circadian time (CT) 20 to 1 hr delay at CT 12; late phase changes are larger, the maximal advance being 12 hr at CT 16 and the greatest delay, 10 hr at CT 14. It is proposed that the early phase changes are caused by alterations in the ion distribution across membranes as a consequence of the permeation of cycloheximide. Late phase changes may be the result of inhibition of protein synthesis.The phase response curve for the late phase change is identical to that obtained with saturating light pulses in otherwise constant darkness in Gonyaulax. Maximal phase changes drive the clock into the part of the circadian cycle between CTs 4 and 9. Perturbations in this part of the circadian cycle are without effect on phase. Incubation of Gonyaulax with cycloheximide for a critical duration at a critical time induces arhythmicity, but longer exposures to the inhibitor at the same time do not. This observation suggests the existence of a singularity in the circadian clock of Gonyaulax.

L-659,066 has been characterized as a potent and selective alpha-2 adrenoceptor antagonist. Both in vitro and in vivo, L-659,066 exhibited specificity (comparable to rauwolscine) for alpha-2 over alpha-1 adrenoceptors. Studies comparing L-659,066 with a previously described antagonist, L-657,743, demonstrate that the new compound penetrates the blood-brain barrier only poorly after systemic administration. With a pA2 of 8.44 at alpha-2 adrenoceptors in the isolated rat vas deferens and an IC50 of 3.0 nM against the binding of [3H]rauwolscine to rat cerebrocortical membranes, L-659,066 possessed, respectively, about one-eighth and one-third of the potency of L-657,743. Similar relative potencies were obtained in vivo in pithed rats with regard to blocking peripherally located postjunctional and prejunctional alpha-2 adrenoceptors (L-659,066 = one-seventh and one-fourth of L-657,743, respectively). In tests carried out in vivo with rats for ascertaining alpha-2 adrenoceptor antagonism in the central nervous system--namely, accumulation of cortical dopa and antagonism of mydriasis induced by the alpha-2 agonist, clonidine--L-659,066 had, respectively, less than 1/345th and about 1/5000th of the potency of L-657,743. In mice, L-659,066 had, respectively, approximately 1/29th and 1/1400th of the potency of L-657,743 as an antagonist in vivo of the predominately peripherally mediated inhibition of colonic propulsion caused by clonidine as compared with the mainly centrally mediated antinocisponsive action elicited by the alpha-2 agonist UK 14,304. The foregoing findings are consistent with poor penetration of the blood-brain barrier by L-659,066.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell-free extracts that show activity in photosynthetic electron flow have been prepared from the unicellular dinoflagellate, Gonyaulax polyedra. Electron flow, as O(2) uptake, was measured through both photo-system I and II from water to methyl viologen, through photosystem I alone from reduced 2,6-dichlorophenol indophenol to methyl viologen which does not include the plastoquinone pool or from duroquinol to methyl viologen which includes the plastoquinone pool. Electron flow principally through photosystem II was measured from water to diaminodurene and ferricyanide, as O(2) evolution. Cultures of Gonyaulax were grown on a 12-hour light:12 hour dark cycle to late log phase, then transferred to constant light at the beginning of a light period. After 3 days, measurements of electron flow were made at the maximum and minimum of the photosynthetic rhythm, as determined from measurements of the rhythm of bioluminescence. Photosynthesis was also measured in whole cells, either as (14)C fixation or O(2) evolution. Electron flow through both photosystems and through photosystem II alone were clearly rhythmic, while electron flow through photosystem I, including or excluding the plastoquinone pool, was constant with time in the circadian cycle. Thus, only changes in photosystem II account for the photosynthesis rhythm in Gonyaulax.

Circadian rhythms in photosynthesis were defined for the first time in the dinoflagellates Glenodinium sp. (M. Bernard strain) and Ceratium furca Ehrenberg (B. Meeson strain) and compared with that in Gonyaulax polyedra Stein. All three phytoplankton species had photosynthetic rhythms with daily amplitudes ranging from 3 to 5 and maxima displayed about midday. The photosynthetic pigment content and absorption properties of the cells were constant over the circadian cycle. Diurnal periodicities in respiration never accounted for more than 30% of the photosynthetic rhythm and did not persist under constant conditions. There was sufficient similarity between the circadian rhythms of these three dinoflagellates to suggest the mechanism of regulation may be the same for each of them.

The metabolism of the PAF antagonists kadsurenone and tritium-labeled 9,10-dihydrokadsurenone was studied in rhesus monkeys and rat liver microsomes. The monkey metabolites of the two drugs were isolated as their glucuronide conjugates from the urine of iv dosed males. The metabolites from both monkey and microsomal metabolism were purified by reverse phase HPLC and identified by spectral (NMR, UV, and mass spectrometric) analysis. The principal pathway of biotransformation of the tritium-labeled 9,10-dihydrokadsurenone in monkeys was hydroxylation of the C-5 propyl side chain to give two metabolites, 10-hydroxy-9,10-dihydrokadsurenone and 9-hydroxy-9,10-dihydrokadsurenone. These compounds were excreted as glucuronides. Microsomal incubation of tritium-labeled 9,10-dihydrokadsurenone yielded the 10-, 9-, and 8-hydroxy-9,10-dihydrokadsurenone as major metabolites. Kadsurenone was also metabolized at the C-5 side chain, an allyl group. The monoglucuronide of 9,10-dihydroxykadsurenone was isolated from monkey urine. Spectral analysis was not definitive as to the site of conjugation, and the structure of the metabolite was assigned as the C-10 conjugate. A major metabolite of rat liver microsomal incubation of kadsurenone was 9,10-dihydroxykadsurenone.

Using data from light-dark cultures of Gonyaulax polyedra entrained to a 24-hour cycle, whole cell absorption curves and photosynthesis-irradiance curves were constructed for various circadian times. While whole cell absorbance and half-saturation constants of photosynthesis showed no statistical difference that could be directly related to the photosynthetic rhythm, the initial slope of the photosynthesis-irradiance curve was a time-dependent parameter which altered in direct proportion to the change in photosynthetic capacity. The results indicated a temporal change in the relative quantum yield of photosynthesis, and the circadian rhythmicity of light-limited photosynthesis was established under constant conditions. Circadian rhythmicity was detected in room temperature chlorophyll fluorescence yield. Low temperature fluorescence kinetics also showed fluctuations. The results suggest that regulation of photosynthesis by the biological clock of Gonyaulax may be mediated through the membrane-bound light reactions and a partial explanation of the underlying mechanism is proposed.

The circadian rhythms in bioluminescence and photosynthesis in Gonyaulax polyedra suspended in unsupplemented sea water have been compared to the same rhythms in f/2, an enriched seawater medium. Cells suspended in sea water for 2 days in continuous light (450 microwatts per square centimeter) showed significantly shorter circadian periods and lower amplitudes than did cells in f/2 medium (a period of 22.2 hours as compared to 23.5 hours). Both period and amplitude changes could be completely reversed by the addition of nitrate at one-fourth or more of the concentration in f/2 medium (0.88 millimolar). The addition to autoclaved seawater of phosphate, vitamins, minerals, or soil extract in concentrations present in f/2 medium had no effect. Thus, the shortening of the circadian period is the consequence of reduced nitrogen supply. Since both the rhythms in bioluminescence and photosynthesis showed similarly shortened circadian periods and lower amplitudes, it is probable that the depletion of nitrate directly affects the circadian clock.

Viable spheroplasts of a marine dinoflagellate, Gonyaulax polyedra, have been prepared for the first time. This simple and rapid procedure results in a yield of over 95% intact spheroplasts. Utilizing this technique, many studies of the cell-wall-free form of this dinoflagellate are now possible.

Circadian rhythms in acid-stimulated bioluminescence and cell division are observed for at least 16 days in bright continuous light (4.5 milliwatts per square centimeter or 20,000 lux). The photosynthesis rhythm also fails to stop immediately upon transfer of cell suspensions to bright light. After about 4 weeks under these conditions, all rhythms were observed to damp out. In cells transferred from bright light to continuous darkness, the rhythms were reset to about circadian hour 12 to 14, the phase of the beginning of a normal night.

Exposure for 4 hours to vanillic acid (4-hydroxy 3-methoxy benzoic acid) caused large delay phase shifts (5 to 6 hours) in the circadian rhythm of bioluminescence in Gonyaulax polyedra, when assayed at either 10 to 14 circadian time or 22 to 02 circadian time in constant light and temperature, provided that the pH of the medium was 7.1 or lower. Corresponding changes in the pH with acetic acid did not shift phase. Vanillic acid caused detectable depolarization of the membranes of Gonyaulax, as demonstrated with the cyanine dye fluorescence technique.

A circadian rhythm in the intracellular level of K(+) in Gonyaulax polyedra is reported. When axenic cultures of Gonyaulax in continuous light (60-75 fot candles) are exposed for 4 hours to 0.1 or 0.2% ethanol, the subsequent free-running rhythm in stimulated bioluminescence is phase-shifted, the amount and direction of the shift being dependent on the time in the circadian cycle when cells are treated. The phase-response curve for ethanol closely resembles that for light in similarly maintained cells. When valinomycin (0.1 or 0.2 mug ml(-1)) is present in addition to ethanol, the phase of the bioluminescence rhythm is returned to that of an untreated cell suspension. Valinomycin thus negates the effect of ethanol on phase. The intracellular K(+) level immediately after treatment of a cell suspension for 4 hours with ethanol (0.1%) is about half that of untreated cells. If valinomycin (0.1 mug ml(-1)) is also present during the 4-hour treatment, the intracellular K(+) is only slightly lower than in untreated cells. Increasing the external concentration of K(+) or Na(+) for 4 hours has no effect on the rhythm of stimulated bioluminescence. These results are interpreted as support for the hypothesis that the mechanism by which circadian oscillations are generated involves changes in membrane properties.

In order to discover the intracellular location of luciferase in dinoflagellates, sections from a number of species were treated with a polyclonal anti-luciferase and the bound antibody was visualized at the electron-microscope level by indirect immunogold labelling. In two species of Pyrocystis and in Noctiluca, as in Gonyaulax, antibody became bound to dense vesicles, which correspond in size and position to light-emitting bodies detected in previous work. These vesicles resemble microsomes, are bounded by a single membrane and sometimes project into the vacuole. Unexpectedly, the trichocysts of Gonyaulax and Noctiluca and the related mucocysts of Pyrocystis also bound the antibody. This cross-reaction seems quite independent of bioluminescence, since the trichocysts of the non-luminous Cachonina also reacted positively. The possibility is discussed that a protein, different from luciferase but having some antigenic similarity, is present in trichocysts and related organelles.

The luminescence of the marine dinoflagellate Gonyaulax polyedra shows an endogenous diurnal rhythm. The effect of light during the phase of low luminescence capacity may be observed as an enhancement of luminescence during the subsequent bright phase. During the bright phase, however, illumination diminishes the capacity for luminescence. The action spectra for these two effects of light have been determined, and the major pigments of Gonyaulax have been examined. A consideration of the action spectrum and the pigment complement of Gonyaulax suggests that photosynthesis during the day is responsible, directly or indirectly, for the enhancement of luminescence during the following night. Photoinhibition of luminescence is in part attributable to light absorbed by the photosynthetic pigments. However, activity observed in the far red region of the spectrum beyond the absorption maximum of chlorophyll a suggests that an additional pigment, present in small amounts, may also act as sensitizer for photoinhibition.

The ribulose 1,5-diphosphate carboxylase from Gonyaulax polyedra Stein. has a half-life of about four hours in buffer, but can be stabilized by the addition of 50% glycerol. The optimum pH is 7.8 to 8.0 and the optimum Mg(2+) concentration is 3 mm. Heavy metal ions (Cu(2+), Hg(2+), Ni(2+), Zn(2+)), EDTA, pyrophosphate, and adenosine triphosphate were strongly inhibitory. Ribulose 1,5-diphosphate carboxylase from Gonyaulax was not cold-sensitive or activated by light activation factor from tomato or Gonyaulax. No difference in the activity of this enzyme was detected when extracts prepared at the maximum and the minimum of the circadian rhythm of photosynthesis were compared. The Km of HCO(3) (-) was also the same (16 to 19 mm).

1. A further study has been made of the effect of indole-3-acetic acid (auxin) on protoplasmic streaming in the epidermal cells of the Avena coleoptile. 2. The transient nature of the effect of auxin, both in accelerating and retarding streaming, is due to the temporary exhaustion of carbohydrate from the tissues. In presence of 1 per cent fructose or some other sugars the acceleration or retardation of streaming by auxin is not transient, but is maintained for at least 2 hours. 3. The retardation of streaming brought about by concentrations of auxin above 0.5 mg. per liter is due to oxygen deficiency This has been confirmed in several ways. 4. It follows that the effect of auxin is to increase the respiration of the coleoptile tissue. 5. Younger coleoptiles, 3 cm. long, are sensitive to lower concentrations of auxin than those 5 cm. long, and more readily exhibit oxygen deficiency as a result of the action of auxin. However, after decapitation their response to auxin more closely resembles that of 5 cm. coleoptiles. 6. The retardation of streaming in such coleoptiles, resulting from oxygen deficiency, is delayed by very dilute solutions of histidine. On this basis an explanation is suggested for the results of Fitting on streaming in Vallisneria leaves. 7. The mean rate of streaming in control untreated coleoptiles in pure water varies with the time of year, but not with the time of day. 8. The results support the view that auxin accelerates an oxygen-consuming process which controls the rate of protoplasmic streaming, and that the latter controls growth. The substrate for this process is probably sugar. 9. It is suggested that auxin also accelerates another oxygen-consuming process, which may withdraw oxygen from the process which controls streaming rate and hence cause retardation of the latter.

Anucleate Acetabularia crenulata shows a circadian rhythm in photosynthesis. In this study, an oxygen electrode was employed to measure this photosynthetic rhythm in the presence and absence of the inhibitors, actinomycin D, chloramphenicol, and puromycin. High concentrations of the inhibitors were used: actinomycin D, 20-40 micrograms ml-1; puromycin, 30 and 100 micrograms ml-1; and chloramphenicol, 250 micrograms ml-1. The effectiveness of these inhibitors on protein synthesis was also measured under the same conditions used for the determination of rhythmicity. In spite of large effects of all three inhibitors on the incorporation of 14C leucine, no effect on the period or the phase of the photosynthetic rhythm was observed. The higher concentration of puromycin and chloramphenicol produced toxic effects which were expressed as a reduction in the amount of photosynthesis, but rhythmicity was still apparent. After 3 or 4 days' exposure to actinomycin, Acetabularia became resistant to its effect. Recovery was also observed in the ability to incorporate leucine. The implications of these results for theories of the basic oscillator responsible for circadian rhythmicity are discussed.

Evidence is presented for an endogenous rhythm which controls gamete formation in the coenocytic gametophytic stage of the marine alga Derbesia tenuissima (De Notaris) Crouan fr. (Chlorophyceae), formerly known as Halicystis parvula. The rhythm is present under conditions of constant light and temperature, or in alternating light and darkness (LD 12 :12 or LD 8 : 8). Under controlled conditions in the laboratory, the basic period of this rhythm is 4-5 days. The period is affected very little by temperature or light intensity. Gametangia may appear only at every other cycle of the underlying rhythm at approximately 8-day intervals, or even every third cycle at intervals of about 12 days. The observation that the interval between the appearance of new gametangia does not vary continuously when light or temperature is varied but tends to be a multiple of 4 days is the strongest evidence available that a true endogenous rhythm with a period of about 4 days is present in Derbesia. Evidence is presented that circadian rhythmicity does not play a part in the timing of the initiation of gametangia in this organism.

The unicellular alga Acetabularia was found to show a diurnal rhythm in photosynthesis. This rhythm continued for at least three cycles in constant light and temperature, and hence can be considered endogenous. Plants from which the nucleus had been removed by severing the basal rhizoids showed no modification in the photosynthetic rhythm over a number of cycles. The nucleus is, therefore, not immediately essential for the maintenance of rhythmicity in Acetabularia. Conversely, a mechanism for sustaining time-keeping must exist in the cytoplasm.

A water-soluble peridinin-chlorophyll-protein complex from the dinoflagellate Gonyaulax polyedra was found to have a molecular weight of about 38,000. The complex could be disrupted by digestion with proteolytic enzymes. No electron transfer was observed when the complex was irradiated.

A new method for the stimulation of bioluminescence in the dinoflagellate Gonyaulax polyedra is described. With this technique, in which cells flow through a capillary coil, it is possible to graduate the intensity of the stimulus by varying the flow rate. In continuous darkness, the threshold stimulus for cells in the middle of the day phase is greater than that for cells in the middle of the night phase. Some evidence suggests heterogeneity of sensitivity to stimulation among either cells or individual luminescent sources within a cell. At stimulus intensities much above threshold, the luminescence of both day- and night-phase cells is proportional to the number of cells within the capillary coil. Night-phase cells emit about 14 times as much light as do day-phase cells in continuous darkness.Single bioluminescent flashes from cells were recorded with a high speed camera. No significant difference in flash kinetics was found between cells in the day and the night phase in continuous darkness. Cells in the night phase emit a flash three to five times brighter than that from day-phase cells. About twice as many flashes are recorded in a given time from a population of night-phase cells.The activity of both luciferin and luciferase have been shown to vary rhythmically. The differences in threshold and number of flahses are evidence for a second component of the circadian rhythm in luminescence, a rhythm in sensitivity to stimulation.

1. Evidence has accumulated that the action of auxins in promoting growth is exerted not upon the cell wall but upon the cell contents; i.e., the protoplasm. Following indications previously obtained, therefore, the effect of auxins on the rate of protoplasm streaming in the Avena coleoptile was studied. 2. Indole-3-acetic acid, the most active auxin available in pure form, was found to increase the rate of streaming in the epidermal cells of the Avena coleoptile at concentrations between 0.5 and 0.002 mg. per liter, the maximum increase being brought about at 0.01 mg. per liter. This concentration is approximately that which, applied in agar to one side of the decapitated coleoptile, would give a curvature of 1 degrees ; i.e., it is well within the range of concentrations active in growth promotion. It is, however, much less than that which produces maximum elongation in immersed sections of Avena coleoptiles. 3. This accelerating effect is readily determined quantitatively by comparison with the streaming in control coleoptiles in pure water, which, if thoroughly aerated, maintain a constant rate for over an hour. The accelerating effect takes place immediately and is over within about 30 minutes. 4. Concentrations of indole-3-acetic acid greater than 0.5 mg.per liter inhibit the streaming, the effect being also over in about 30 minutes, and its extent increasing with increasing auxin concentration. This parallels the effect of high auxin concentrations in inhibiting elongation, although the inhibition of streaming is obtained at much lower concentrations than inhibit elongation. 5. The effects of indole-3-acetic acid on streaming are not specific for that substance, but appear to be common to auxins in general. Thus coumaryl-3-acetic acid and allocinnamic acid, both of which bring about cell enlargement, root formation, and bud inhibition, i.e. are typical auxins, also cause an immediate acceleration of the rate of streaming, and as with indole-acetic add the effect is over in about 30 minutes. The concentrations of these two substances which produce the maximum effect are about ten times that of indole-acetic acid, which approximately corresponds with their relative auxin activities. The curves relating concentrations of these substances to their effects on streaming are very similar to that for indole-acetic acid. 6. On the other hand, certain substances which are known to affect streaming in other materials do not produce any effect comparable to that of auxin. Ethylene chlorhydrin, histidine, and urea in all concentrations were without effect on streaming in the Avena coleoptile within the first 30 minutes of treatment. 7. The effects produced by the auxins were not due to pH. 8. The action on streaming here studied is evidently quite different from the re-starting of streaming after its cessation, studied by Fitting in Vallisneria. Correspondingly histidine, which in Fitting's experiments showed activity down to 10(-7)M, is inactive here. 9. Per contra, the effect of auxin here studied is on normal streaming. It takes place immediately and at concentrations in the same range as those which produce growth. The curve of effect against concentration parallels that for growth although the actual concentration values differ. It is therefore reasonable to suppose that the effect of auxin on streaming is closely connected with one of the first stages of its effect on the growth process.

The luminescent marine dinoflagellate, Gonyaulax polyedra, exhibits a diurnal rhythm in the rate of photosynthesis and photosynthetic capacity measured by incorporation of C(14)O(2), at different times of day. With cultures grown on alternating light and dark periods of 12 hours each, the maximum rate is at the 8th hour of the light period. Cultures transferred from day-night conditions to continuous dim light continue to show the rhythm of photosynthetic capacity (activity measured in bright light) but not of photosynthesis (activity measured in existing dim light). Cultures transferred to continuous bright light, however, do not show any rhythm. Several other properties of the photosynthetic rhythm are similar to those of previously reported rhythms of luminescence and cell division. This similarity suggests that a single mechanism regulates the various rhythms.

The action spectrum for changing the phase of the rhythm of luminescence in the marine dinoflagellate Gonyaulax polyedra has been determined. Maxima in effectiveness were found at 475 and 650 mmicro. The significance of these findings is discussed.