Meeting Announcements

Complex Carbohydrate Research Center Training Courses

Aug 4–8, 2008 Separation and Characterization of GlycoconjugateOligosaccharides

     

Meeting Announcements

Complex Carbohydrate Research Center Training Courses

Aug 4–8, 2008 Separation and Characterization of GlycoconjugateOligosaccharides

     

Meeting Announcements

Complex Carbohydrate Research Center Training Courses

Aug 4–8, 2008 Separation and Characterization of GlycoconjugateOligosaccharides

     

Meeting Announcements

Complex Carbohydrate Research Center Training Courses

Aug 4–8, 2008 Separation and Characterization of     

Meeting Announcements

Complex Carbohydrate Research Center Training Courses

Aug 4–8, 2008 Separation and Characterization of     

EFFECTS OF TEMPERATURE ON CHRONIC HYPOXIA TOLERANCE IN THE NON-INDIGENOUS BROWN MUSSEL, PERNA PERNA (BIVALVIA: MYTILIDAE) FROM THE TEXAS GULF OF MEXICO

Effects of temperature (15°, 20° and 25°C), O₂ partialpressure (P_O2=0, 1, 2, 4, and 6 kPa), and individual size(12–79 mm shell length; SL) on survivorship of specimensof the non-indigenous, marine, brown mussel, Perna perna, fromTexas were investigated to assess its potential distributionin North America. Its hypoxia tolerance was temperature-dependent,survivorship being significantly extended at lower temperaturesunder all tested lethal P_O2. Incipient tolerated P_O2 was 4 and6 kPa at 15 and 20°C, respectively, with >50% mortalityoccurring at 25°C at all tested levels of hypoxia. P_O2 hadless of an effect on survival of hypoxia than temperature. At25°C, survivorship was not different over a P_O2 range of0–2 kPa and increased only at 4 and 6 kPa. Survivorshipwas size-dependent. Median survival times increased with increasingSL in anoxia and P_O2=1 kPa, but at 2, 4 and 6 kPa,smaller individuals survived longer than larger individuals.With tolerance levels similar to other estuarine bivalve species,P. perna should withstand hypoxia encountered in estuarine environments.Thus, its restriction to intertidal rocky shores may be dueto other parameters, particularly its relatively low temperaturetolerance. (Received 26 January 2004; accepted 31 March 2005)     

Feeding and growth rates of the doliolid, Dolioletta gegenbauri Uljanin (Tunicata, Thaliacea)

The goal of this research is to enhance our knowledge of thecontributions of doliolids to the planktonic community as consumersand secondary producers. The objectives are to quantify feedingand growth rates of Dolioletta gegenbauri gonozooids at fourfood concentrations and four temperatures in order to determinetheir impact as grazers throughout the water column. Althoughdoliolids are abundant in numerous regions of the coastal ocean,and are considered to be major planktonic grazers, data on ratesof feeding and growth are scarce. Laboratory experiments wereconducted at 16.5, 20, 23.5 and 26.5°C to quantify removalof a 50:50 volumetric concentration of Thalassiosira weissflogiiand Rhodomonas sp. at four different food concentrations of20, 60, 160 and 390 µg C l^–1. Results from theseexperiments suggest that clearance rates are similar at concentrationsfrom 20 to 60 µg C l ^–1, and decrease as the foodconcentrations increase to 160 and 390 µg C l ^–1.The ingestion rates increase over a range of phytoplankton concentrationsfrom 20 to 160 µg C l ^–1, then decrease when abnormallyhigh concentrations of 390 µg C l ^–1 are offered.Clearance and ingestion rates increase as temperature increasesfrom 16.5 to 26.5°C. The exponential growth rates rangefrom k = 0.2–0.7, with the lowest rates occurring at thehighest food concentration. Growth rates increase with increasingtemperature from K = 0.1–0.3 at 16.5°C to 0.45–0.7at 26.5°C. In each case, the small- and medium-sized zooidshad higher growth rates than the larger gonozooids. These resultssuggest that doliolid feeding and growth rates are a functionof environmental food concentrations and temperatures, and implythat they can be important consumers in a changing neritic environment.     

Optimal adaptive randomized designs for clinical trials

Optimal decision-analytic designs are deterministic. Such designsare appropriately criticized in the context of clinical trialsbecause they are subject to assignment bias. On the other hand,balanced randomized designs may assign an excessive number ofpatients to a treatment arm that is performing relatively poorly.We propose a compromise between these two extremes, one thatachieves some of the good characteristics of both. We introducea constrained optimal adaptive design for a fully sequentialrandomized clinical trial with k arms and n patients. An r-designis one for which, at each allocation, each arm has probabilityat least r of being chosen, 0 r 1/k. An optimal design amongall r-designs is called r-optimal. An r₁-design is also an r₂-designif r₁ r₂. A design without constraint is the special case r = 0and a balanced randomized design is the special case r = 1/k.The optimization criterion is to maximize the expected overallutility in a Bayesian decision-analytic approach, where utilityis the sum over the utilities for individual patients over a‘patient horizon’ N. We prove analytically thatthere exists an r-optimal design such that each patient is assignedto a particular one of the arms with probability 1 – (k – 1)r,and to the remaining arms with probability r. We also show thatthe balanced design is asymptotically r-optimal for any givenr, 0 r < 1/k, as N/n  . This implies that everyr-optimal design is asymptotically optimal without constraint.Numerical computations using backward induction for k = 2arms show that, in general, this asymptotic optimality featurefor r-optimal designs can be accomplished with moderate trialsize n if the patient horizon N is large relative to n. We alsoshow that, in a trial with an r-optimal design, r < 1/2,fewer patients are assigned to an inferior arm than when followinga balanced design, even for r-optimal designs having the samestatistical power as a balanced design. We discuss extensionsto various clinical trial settings.     

Responses by Coleoptiles of Intact Rice Seedlings to Anoxia: K+ Net Uptake from the External Solution and Translocation from the Caryopses

This study evaluated the effects of anoxia on K⁺ uptake andtranslocation in 3–4-d-old, intact, rice seedlings (Oryzasativa L. cv. Calrose). Rates of net K⁺ uptake from the mediumover 24 h by coleoptiles of anoxic seedlings were inhibitedby 83–91 %, when compared with rates in aerated seedlings.Similar uptake rates, and degree of inhibition due to anoxia,were found for Rb⁺ when supplied over 1·5–2 h,starting 22 h after imposing anoxia. The Rb⁺ uptake indicatedthat intact coleoptiles take up ions directly from the externalsolution. Monovalent cation (K⁺ and Rb⁺) net uptake from thesolution was inhibited by anoxia to the same degree for thecoleoptiles of intact seedlings and for coleoptiles excised,‘aged’, and supplied with exogenous glucose. Transportof endogenous K⁺ from caryopses to coleoptiles was inhibitedless by anoxia than net K⁺ uptake from the solution, the inhibitionbeing 55 % rather than 87 %. Despite these inhibitions,osmotic pressures of sap (_sap) expressed from coleoptiles ofseedlings exposed to 48 h of anoxia, with or without exogenousK⁺, were 0·66 ± 0·03 MPa; however,the contributions of K⁺ to _sap were 23 and 16 %, respectively.After 24 h of anoxia, the K⁺ concentrations in the basal10 mm of the coleoptiles of seedlings with or without exogenousK⁺, were similar to those in aerated seedlings with exogenousK⁺. In contrast, K⁺ concentrations had decreased in aeratedseedlings without exogenous K⁺, presumably due to ‘dilution’by growth; fresh weight gains of the coleoptile being 3·6-to 4·7-fold greater in aerated than in anoxic seedlings.Deposition rates of K⁺ along the axes of the coleoptiles werecalculated for the anoxic seedlings only, for which we assessedthe elongation zone to be only the basal 4 mm. K⁺ depositionin the basal 6 mm was similar for seedlings with or withoutexogenous K⁺, at 0·6–0·87 µmolg^–1 f. wt h^–1. Deposition rates in zones above6 mm from the base were greater for seedlings with, thanwithout, exogenous K⁺; the latter were sometimes negative. Weconclude that for the coleoptiles of rice seedlings, anoxiainhibits net K⁺ uptake from the external solution to a muchlarger extent than K⁺ translocation from the caryopses. Furthermore,K⁺ concentrations in the elongation zone of the coleoptilesof anoxic seedlings were maintained to a remarkable degree,contributing to maintenance of _sap in cells of these elongatingtissues.     

Identification, distribution and relative abundance of paralarval gonatid squids (Cephalopoda: Oegopsida: Gonatidae) from the Gulf of Alaska, 2001 2003

Paralarvae of the family Gonatidae were sampled in the Gulfof Alaska during spring 2001–2003. Taxonomic characterswere determined to allow identification of the specimens tospecies. The dorsal head chromatophore pattern (DHCP) was themost robust character and allowed identification to speciesfor the first time without requiring the removal and examinationof the radula. Six different DHCPs were found among the sixspecies in the study area. The 1140 specimens collected consistedof the following six species: Berryteuthis anonychus (759),Berryteuthis magister (71), Gonatopsis borealis (155), Gonatuskamtschaticus (1), Gonatus madokai (4) and Gonatus onyx (143).The specimens had a size range of 3.0–20.63 mm dorsalmantle length with the majority of specimens smaller than 10 mm.All species showed an increasing trend in abundance from theshelf (0–200 m) to the slope (200–1000 m)to the basin (>1000 m) except G. onyx in 2001 and 2002.Wide variation in distribution and abundance was found for thefour most abundant species; however, in general, B. anonychuswas most abundant and widely distributed, followed by Gonatopisborealis, Gonatus onyx and B. magister. (Received 28 April 2006; accepted 1 February 2007)     

Lam, E., Fukuda, H., Greenberg, J., eds. Programmed cell death in higher plants

‘For everything there is a season . . . a timeto build up and a time to break down . . . a timeto live and a time to die.’ The quotation comes from the work of a Jewish scholar writingunder the pen name Ecclesiastes or The Preacher, several centuriesBC. His words capture the theme of the book under review here:that death is part of life and may be regulated by factors thatinclude time and season. Programmed cell death in higher plantsis a hardback reprint of a special edition of Plant MolecularBiology, devoted to scholarly     

Errata

J. R. Gorst, M. Slaytor and R. A. de Fossard, Vol. 34, No. 148,pp. 1503–1515 P.1503. ABSTRACT, line 1 should read: Shoot explants from seedling-derived cultures ... P.1504. line 1 should read: Tlaskal, 1974)... P.I504. MA TERIALS AND METHODS, line 3 should read: calcium hypochlorite in 0.1% (v/v) 7X detergent ... P.1505. Twelfth line from bottom should read: Anatomical features were studied on 12,um ... P.1505. Third line from bottom should read: (c) 2000 µmol m^–2 s^–1— 0, 0.5, 1, 2,3,4, 5, 8, 10 min P.1507. RESULTS, line 2 should read: Root Types I and II ... P.1508. Lines 13–15 should read: ... explants on Medium R minus riboflavin would always producea Type II root system whilst those on Medium R plus riboflavinand incubated in the light would always produce a Type I rootsystem. P.1509. Paragraph 2, additional sentence: Cultures incubated in the dark for less than 9 d on Medium Rplus riboflavin could still produce Type I roots if exposedto light. P.1510. Table 2, second line of data should read: 2 5/9 0/9 3/9 0/9 1/10 0/10 P.I 510. Eleventh line from bottom should read: ... change in root morphogenesis. P.1511. Table 3, first column DB should read BD P.1514. LITERATURE CITED, line 2 should read: ... Botanical Sciences Section, 208–10, 102–5.     

Photoadaptation in Antarctic phytopfankton: variations in growth rate, chemical composition and P versus I curves

The response of phytoplankton to variations in the light regimewas studied during the VULCAN and ACDA cruises in the Antarctic.Unenriched batch cultures of 12–19 days' duration reachedchl concentrations of 10–50 µg^–1 and exhibitedexponential growth rates, with the maximal rate being 0.41 doubl,day^–1. Ice edge algae exhibited maximum growth rates atphoton flux densities (PFD) of 30–100 µE m^–2S^–1and the growth rate was reduced by about 30% at 500–1000µE m^–2S^–1 The chl/C ratio ranged between 0.004and 0.018, with the lowest ratios at PFDs above 500 µEm^–2S^–1 chl/C ratios were also below maximum at PFDsbelow 40–50 µE m^–2S^–1 The C:N:P ratioswere close to the Redfield ratios; the Si/C ratio averaged 0.16(atoms), and the ATP/C ratio averaged from 0.0024 to 0.0050in different culture senes. When thawed after having been frozenfor 10 days, shade-adapted cultures were in a much better conditionthan sun-adapted ones. P versus I data showed that the maximumassimilation number varied from 0.75 to 4.4 µg C (µgchl)^–1h^–1. It varied inversely with the chl/C ratio;therefore the maximum carbon turnover rate varied little betweensamples (0.024/0.035 h^–1). Low biomass communities exhibitedrelatively high values for (the initial slope of P versus Icurves), low values for 1_sat (160–330 µE m^–2S^–1),and they were susceptible to photoinhibition. In contrast, communitiesdominated by Odontella weissflogii exhibited low values for, a high value for I_sat (560 µE m^–2S^–1 andthey tolerated high PFDs. The photo-adaptational status of thephytoplankton in natural water samples is discussed relativeto the profile of water column stability and mixing processes.     

Asexual reproduction of the doliolid, Dolioletta gegenbauri Uljanin (Tunicata, Thaliacea)

The goal of this research is to enhance our knowledge of thecontributions of doliolids to the planktonic community as consumersand secondary producers. The objectives are to quantify asexualreproduction and carbon release rates of Dolioletta gegenbauriphorozooids at four food concentrations and four temperaturesin order to determine their impact as producers throughout thewater column. Although doliolids are abundant in numerous regionsof the coastal ocean, and are considered to be major planktonicgrazers, data on rates of asexual reproduction are scarce. Laboratoryexperiments were conducted at 20°C at food concentrationsof 7, 20, 60 and 160 µg C l^-1 of Thalassiosira weissflogiiand Rhodomonas sp., and at 60 µg C l^-1 at 16.5, 20, 23.5and 26.5°C, to quantify the phorozooid release rates ofgonozooids, and the amount of carbon released. Results fromthese experiments suggest that release rates increased at 20°Cas concentration increases from 7 to 160 µg C l^-1. Releaserates remained similar as the temperature increased from 16.5to 26.5°C at a phytoplankton concentration of 60 µgC l^-1. Food concentration and temperature has an effect on phorozooidreproductive longevity, size of gonozooids released, and theamount of carbon released asexually. Doliolid reproduction ratesare a function of environmental food concentrations and temperatures,and the results imply that doliolids can be important secondaryproducers in the neritic environment.     

Homocysteine, vitamins B6, B12, folate, and risk of coronary artery disease in patients undergoing diagnostic coronary angiography

Summary. Homocysteine and vitamins B were correlated with coronary artery disease in patients undergoing diagnostic coronary angiography. 160 patients having ≧1 stenosis (G1), 55 patients having normal coronary arteries (G2) and 171 healthy volunteers (G3) were prospectively recruited. Homocysteine levels were significantly higher in patients, particulary in those with normal coronary angiograms, than in healthy subjects (13.8 ± 6.3 μmol/L in G1 (p < 0.0001) and 15.2 ± 8.8 μmol/L in G2 (p < 0.0001) versus 10.1 ± 3.1 μmol/L in G3). Homocysteine levels were not related to the extent of coronary artery disease. In patients with normal angiogram, vitamin B12 and folate levels were significantly higher compared with the other groups (p < 0.05 and p < 0.001, respectively) showing that vitamin B deficiency was not involved in the hyperhomocysteinemia. In conclusion, homocysteine and vitamins B levels do not contribute to discriminate for the presence of coronary artery disease in patients undergoing diagnostic coronary angiography. Homocysteine levels, however, were higher in patients referred for coronary angiography than in healthy controls. Received November 7, 1998, Accepted February 20, 1999     

POPULATION DYNAMICS OF ZEBRA MUSSELS DREISSENA POLYMORPHA (PALLAS, 1771) DURING THE INITIAL INVASION OF THE UPPER MISSISSIPPI RIVER, USA

The aim of this study was to document and model the populationdynamics of zebra mussels Dreissena polymorpha (Pallas, 1771)in Pool 8 of the Upper Mississippi River (UMR), USA, for fiveconsecutive years (1992–1996) following their initialdiscovery in September 1991. Artificial substrates (concreteblocks, 0.49 m² surface area) were deployed on or aroundthe first of May at two sites within each of two habitat types(main channel border and contiguous backwater). Blocks wereremoved monthly (30 ± 10 d) from the end ofMay to the end of October to obtain density and growth information.Some blocks deployed in May 1995 were retrieved in April 1996to obtain information about over-winter growth and survival.The annual density of zebra mussels in Pool 8 of the UMR increasedfrom 3.5/m² in 1992 to 14,956/m² in 1996. The average May–Octobergrowth rate of newly recruited individuals, based on a von Bertalanffygrowth model fitted to monthly shell-length composition data,was 0.11 mm/d. Model estimates of the average survivalrate varied from 21 to 100% per month. Estimated recruitmentvaried substantially among months, with highest levels occurringin September–October of 1994 and 1996, and in July of1995. Recruitment and density in both habitat types increasedby two orders of magnitude in 1996. Follow-up studies will benecessary to assess the long-term stability of zebra musselpopulations in the UMR; this study provides the critical baselineinformation needed for those future comparisons. (Received 5 November 2004; accepted 30 September 2005)     

Development of a bioconversion process for production of cis-1S,2R-indandiol from indene by recombinant Escherichia coli constructs

Recombinant Escherichia coli cells expressing the toluene dioxygenase (TDO) genes from Pseudomonas putida convert indene to cis-1S,2R-indandiol, a potentially important intermediate for the chemical synthesis of the HIV-1 protease inhibitor, Crixivan. A bioconversion process was developed through optimization of medium composition and reaction conditions at the shake-flask and 23-l fermentor scales. A cis-1,2-indandiol productivity of approx. 1000 mg/l was achieved with construct TDO123, which represents a 50-fold increase over the initial titer. Varying the bioconversion conditions did not change the enantiomeric excess (e.e.) for the 1S,2R enantiomer from about 30%, suggesting that toluene dioxygenase intrinsically converts indene to 1S,2R- and 1R,2S-indandiols at a ratio of 2:1. Further inclusion of the Pseudomonas dehydrogenase gene in construct D160-1 led to the production of chirally pure cis-1S,2R-indandiol (e.e. > 99%) as a result of the selective degradation of the 1R,2S enantiomer, with the overall yield (650 mg/l) proportionally reduced. A single stage process was developed for D160-1 and scaled up to the 23-l fermentor, achieving a cis-1S,2R-indandiol titer of 1200 mg/l. Received: 24 September 1998 / Received revision: 22 January 1999 / Accepted: 31 January 1999     

Hippocampus, Temporal Context and Taste Memories

Chemical Senses, 30 (suppl 1): i160–i161, 2005     

Cyst formation: an important mechanism for the termination of Scrippsiella trochoidea (Dinophyceae) bloom

A sediment trap study was conducted at Daya Bay, South ChinaSea, to investigate the relationships between encystment andpopulation dynamics of Scrippsiella trochoidea from December1999 to January 2001. A dense bloom of S. trochoidea occurredduring the study period from August to September 2000, withthe maximum cell number of 3.18 x 10⁴ cells mL^–1.Two morphotypes of cysts, one with a thick calcareous wall (calcifiedcyst) and another without the obvious calcareous cover (non-calcifiedcyst), were observed during this investigation. The morphologicaland excystment characteristics of these two cyst types werestudied as well. Mass encystments of S. trochoidea, with themaximum of 3.05 x 10⁵ cysts m^–2 d^–1for calcified cyst, and 1.54 x 10⁷ cysts m^–2 d^–1for non-calcified cyst, coincided with the maximum abundanceof the vegetative cells. Encystment caused the transfer of atotal of 2.24–4.49 x 10⁸ cells m^–2 vegetativecells from the water column to the sea bottom during the bloomand resulted in a considerable loss of the bloom population.High assemblages of cysts of S. trochoidea were detected inthe surface sediments as well. This rich ‘seed bed’in the surface sediments caused by the high efficiency of encystmentafter blooms acting as a benthic reservoir for future vegetativepopulation, together with the short dormant period (15–26days) and high germination rate (50–90%), may explainthe repeated occurrence of S. trochoidea blooms in Daya Bay.     

Physiological responses of Sargasso Sea picoplankton to nanomolar nitrate perturbations

A study was conducted in July 1989 at three stations in thenorthern Sargasso Sea, where picoplankton (<1 µm)provided approximately half of the standing crop of chlorophyll.Temporal changes in the position of the nitracline at a singlelocation indicated that the vertical supply of nitrate was notat ‘steady-state’ and phytoplankton distributionstracked the nitracline. Our main experimental objective wasto examine the short-term effects of ecologically significantnitrate perturbations (+20 and +100 nM) on the physiologyof <1 µm communities growing at low (nanomolar)ambient nitrate concentrations. A chemiluminescent nitrate methodwas used to measure the time course (up to 4 h) of nitratedisappearance at in situ irradiance, in parallel with measurementsof photosynthetic ¹⁴CO₂ assimilation. Picoplankton growing at<60 nM nitrate rapidly responded to nanomolar nitratesupplements with luxury consumption and enhanced photosynthesisin proportion to their ambient nitrate environment. Light-saturatedSynechococcus populations from the most nitrate-depleted waters(13 nM) had doubled their cellular rate of photosynthesisafter 4 h, in response to a 20 nM nitrate pulse.