Conductometric Method for Detecting Ion Efflux during a Single Action Potential of Chara

A simple device was developed to detect net ion efflux duringa single action potential of Chara as an increase in the electricconductance of the bathing solution. The device showed a sufficientlyhigh sensitivity and rapid response to the increase in the electricconductance. Net efflux of monovalent ions was estimated as65–660 pmol cm^–2 impluse^–1 (average 220 pmolcm^–2 impulse^–1). (Received June 28, 1985; Accepted November 13, 1985)     

Separation of Different Cell Types by Rotating Electric Fields

A new method is proposed for separating different cell typesby application of a rotating electric field technique. Plasmamembrane electrical properties and cell size are critical parametersfor cell separation. A suitable chamber is described and thetheoretical and experimental aspects of cell movement are presented.Kalancho? daigremontiana mesophyll protoplasts traveled witha velocity of about 3–7 µm/s on the agar surfaceat a field strength of 3.5?10³ V/m. (Received April 17, 1985; Accepted September 3, 1985)     

Effects of Auxin and Gibberellin on Conidial Germination and Elongation of Young Hyphae in Gibberella fujikuroi and Penicillium notatum

In Gibberella fujikuroi and Penicillium notatum, IAA, 2,4-Dand GA₃ promoted conidial germination and the elongation ofyoung hyphae. The promotive effects of IAA and GA₃ were additive.In both fungi, the concentrations of endogenous auxin and gibberellinin the culture media were 10^–10 to 610^–12M. (Received April 27, 1985; Accepted August 12, 1985)     

Nitrate Reduction by Cassava

Nitrate reductase (NR) was assayed in vivo in cassava (Manihotesculenta Crantz). Activity in the leaves ranged from 0 to 2.51µmole of NO₃^– reduced g^–1 h^–1, withno activity in the younger leaves (leaf 1 on top). NR activitywas localized in the sides and toward the tip of the lobes ofthe leaf. (Received December 10, 1985; Accepted April 8, 1986)     

A microcomputer program for the identification of tRNA genes

A microcomputer program which locates tRNA genes within longDNA sequences is described. The search is performed either byidentifying tRNA-like secondary structures or by locating eukaryoticRNA polymerase III promoter consensus sequences. The programis also useful in finding inverted repeats allowing the formationof stem-loop secondary structures in tRNA. The program has beendeveloped in BASIC and 6502 Assembler and runs on the AppleII plus and He microcomputers. The execution is quite fast;all the operations are carried out in 1–90 s, dependingon the required task and on the sequence length. Received on March 1, 1985; accepted on April 25, 1985     

Discriminant analysis of promoter regions in Escherichia coli sequences

We have previously developed a general method based on the statisticaltechnique of discriminant analysis to predict splice junctionsin eukaryotic mRNA sequences [Nakata, K., Kanehisa, M. and DeLisi,C. (1985) Nucleic Acids Res., 13, 5327–5340]. In orderto evaluate further applicability of this method, we now analyzethe promoter region of Escherichia coli sequences. The attributesused for discrimination include the accuracy of consensus sequencepatterns measured by the perceptron algorithm, the thermal stabilitymap, the base composition and the Calladine-Dickerson rulesfor helical twist angle, roll angle, torsion angle and propellertwist angle. When applied to selected E. coli sequences in theGenBank database, the method correctly identifies 75 % of thetrue promoter regions. Received on May 15, 1987; accepted on April 17, 1988     

Growth and ingestion rates of larval fish populations in the coastal waters of Israel

Clupeoid larvae were collected on eight cruises between February1984 and February 1985 in the coastal waters of Israel. Fromanalysis of daily growth increments of otoliths, growth ratesof the abundant clupeoids, Engraulis encrasicolus, Sardina pilchardusand Sardinella aurita were found to be 0.55 mm day^–1,0.67 mm day^–1 and 0.60 mm day^–1, respectively, duringthe first month after hatching. Ingestion rates were estimatedusing an equation from the literature relating ingestion andgrowth of larval fish. Ingestion calculated for populationsof fish larvae in pelagic waters ranged from 0 to >23 mgC m^–2 day^–1 with maximum rates observed in April.Annual ingestion by larval fish at a pelagic station near Haifawas calculated to be 2.2 g C m^–2 year^–1, 10–20%of annual primary production estimated from ¹⁴C uptake.     

Optimal alignments of biological sequences on a microcomputer

An algorithm and a program have been developed which enableoptimal alignments of biological sequences on an 8–bitmicrocomputer. The compiled program can process sequences upto 1000 residues on a Commodore 64. Since this program was writtenoriginally in the BASIC language, it may readily be adaptedto other microcomputers with small changes. Received on March 11, 1985; accepted on March 14, 1985     

Macrofauna standing stock of the Dogger Bank. A comparison: III. 1950–54 versus 1985–87. A final summary

The macrofauna communities on the Dogger Bank in April/May 1985–87 were compared with those in April/May 1950–54 (Ursin, 1960). Unpublished data from Birkett on the central and western Dogger Bank from April/May 1952–54 were also used for the comparison. The changes in the communities from the fifties to the eighties were made clear by the increasing species numbers and in an increase or dominance of short-living opportunistic species. In contrast, a decrease in long-living bivalves was found. The total biomass in 1985–87 was 2.5 to 8 times higher than in 1950–54. Similarities between stations were below 20%. Some hypotheses concerning natural and anthropogenic impacts are given to interpret the observed changes.     

A general purpose non-linear curve fitting program for the British Broadcasting Corporation Microcomputer

Software for non–linear curve fitting has been writtenin BASIC to execute on the British Broadcasting CorporationMicrocomputer. The program uses the direct search algorithmPattern–search, a robust algorithm that has the additionaladvantage of needing specification of the Junction without inclusionof the partial derivatives. Although less efficient than gradientmethods, the program can be readily configured to solve low–dimensionaloptimization problems that are normally encountered in lifesciences. In writing the software, emphasis has been placedupon the ‘user interface’ and making the most efficientuse of the facilities provided by the minimal configurationof this system. Received on March 4, 1985; accepted on March 14, 1985     

RECRUITMENT AND LIFE SPAN OF TWO NATURAL MUSSEL POPULATIONS PERNA PERNA(LINNAEUS) AND MYTILUS GALLOPROVINCIALIS (LAMARCK) FROM THE ALGERIAN COAST

Coexisting populations of the mussels, Perna perna and Mytilusgalloprovincialis, were monitored at two sites on the NorthAfrican coast, east of Algiers, over a five year period (1985–1989).While spatfalls were observed throughout the year, only themajor spring-summer recruitment, which occurred during favourableweather conditions, contributed to the renewal of both musselspecies at both sites. Very high densities (>10, 000 ind.m^–2) were observed at both sites, but the mussel bedswere composed principally of young and small specimens due toharvesting of the largest animals for use as bait and for humanconsumption. The maximal length observed was 75 mm in P. pernaand 49 mm in M. galloprovincialis. The life span of the specieswas low, 12–24 months in P. perna and 11–28 monthsin M. galloprovincialis. This survey showed that M. galloprovincialisbecame dominant in both mussel beds due to its resistance todisturbance by human activities. (Received 5 January 1995; accepted 18 April 1995)     

The Variation in Response to Light Intensity and Carbon Dioxide Concentration Shown by Two Cultivars of Chrysanthemum morifolium Grown in Controlled Environments at Two Times of Year

The growth of the cultivar Golden Princess Anne (G.P.A.) wasstudied in controlled announcement cabinets in a range of lightconditions (125–375 J cm^–2 8-h day^–1) andcarbon dioxide concentrations (325–1500 ppm) in all combinationsPlants obtained in January and grown from January to April showedgreater final total dry weight and flower dry weight at bothhigher light intensity and higher carbon dioxide concentrationwith a strong positive interaction between them, whereas plantsobtained in September and grown from September to December didnot respond much to increased carbon dioxide concentration andthere was only a small positive interaction with light intensity.The plants grown from January to April had larger final leafareas, larger mean leaf-area ratios due mainly to larger specificleaf areas, and higher mean specific leaf-water contents comparedwith September–December plants. Despite the differencein specific leaf-water content, leaf area was almost the samelinear function of absolute leaf-water content at both timesof year. The other vegetative parts also had higher specificwater contents throughout the January–April experimentand the lateral branches were longer when compared with thecorresponding values for September–December Flower developmentwas slightly faster in September–December and the plantsbore on average one flowering branch less compared with January–Aprilplants. Plants in the lower light and carbon dioxide conditions hadlower unit leaf rates, but for plants of similar total dry weightthe effects of this on dry-matter increment were partially offsetby larger leaf areas at both times of year. The January–Aprilplants had greater leaf areas than September–Decemberplants of similar unit leaf rate and total dry weight. The cultivar Bright Golden Anne (B.G.A ) showed effects whichwere in the same direction but smaller in magnitude, tendingto diminish the differences between the times of year For example,the positive interaction in total plant dry weight was smallerin January–April compared with G P A , but larger in September–December.Leaf area, leaf-area ratio, specific leaf area, specific watercontent of leaf, stem, and root, and lateral branch length,were all larger for B G A in corresponding treatment-combinationsin two January–April experiments than in a September–Decemberone, although the difference between the times of year was smallerthan for G.P.A except for leaf area which was relatively butnot absolutely smaller Dry-matter increment and leaf area showedan inverse relationship for plants of the same total dry weight,as in G P A. In January–April B G.A plants of similarunit leaf rate and total dry weight also had greater leaf areasthan in September–December but the differences were notso large as for G.P.A Total dry-matter production was slightlygreater for B.G.A. in January–April and considerably greaterin September–December compared with G P A , and at bothtimes of year B.G.A. was more leafy, with higher specific watercontents for the vegetative parts. It was not possible to determine the cause of the differencesin growth obtained at the two times of year. It could have arisenbefore the cuttings were removed from the stock plants, duringpropagation, or during the course of the experiments in thegrowth cabinets.     

Estimating the Bioenergetic Cost of a Developing Kiwifruit Berry and its Growth and Maintenance Respiration Components

A response surface was developed by regression analysis to quantifythe seasonal respiratory losses by a kiwifruit [Actinidia deliciosa(A. Chev.) C. F. Liang et A. R. Ferguson var. deliciosa cv.Hayward] berry growing in Fresno, CA. The equation of the surfacewas LNRESP = 1·622 + 0·0697 x TEMP –0·0472x DAY + 0·000165 x DAYSQ, where LNRESP is the naturallogarithm of the respiration rate (nmol CO₂ g d. wt^–1s^–1), TEMP is fruit temperature (°C), DAY is the numberof days after flowering, and DAYSQ is the square of the numberof days after flowering. Respiratory losses for a fruit witha final dry mass of 18·5 g were calculated to be 5·57and 5·92 g glucose per fruit per season in 1985 and 1986,respectively. Maintenance respiration was estimated to be 2·84and 3·19 g glucose per fruit per season for 1985 and1986, respectively. The total calculated bioenergetic cost ofkiwifruit berry growth and respiration was 25·25 and25·60 g glucose per fruit per season for 1985 and 1986,respectively. Respiratory losses, expressed as a proportionof the total carbohydrate required for fruit growth, were significant(mean 22·6%). The cost of fruit growth was estimatedto be very similar for two cooler sites (Davis and Watsonville)but estimates of maintenance respiration based on Fresno fruitrespiration data were unrealistically low for the Watsonvillesite. Actinidia deliciosa (A. Chev.) C. F. Liang et A. R. Ferguson var. deliciosa cv. Hayward, kiwifruit, growth respiration, maintenance respiration, bioenergetic costs, model     

Notes on the Captive Life History of the Carnivorous Katydid Lirometopum coronatum Scudder (Orthoptera: Tettigoniidae) from Costa Rica

SYNOPSIS. Four adult females of the katydid Lirometopum coronatumScudder (Orthoptera: Tettigoniidae: Copiphorinae) were collectedat night near the Old Lab building at Finca La Selva ResearchStation in Costa Rica 12–14 April 1983. From laboratoryobservations, this katydid appears to be primarily nocturnaland carnivorous. These and subsequent generations (through F3)were maintained in the Insect Zoo at the San Francisco ZoologicalGarden from April 1983 to December 1985. Propagation methodswere developed. Life history and behavior data were recorded:F1 females ranged in adult body size from 46 mm to 55 mm; adultovipositor length ranged from 19 mm to 27 mm; from hatchingto death ranged from 189 to 301 days; with an average life spanof 239. Males ranged in adult body size from 41 mm to 47 mm;age ranged from 164 to 390 days; with an average life span of308 days. Both stridulation and leaf shaking was observed inmales.     

Reactivation of Cytoplasmic Streaming in a Tonoplast-Permeabilized Cell Model of Acetabularia

To find whether cytoplasmic streaming in Acetabularia is controlledby Ca²⁺, a tonoplast-permeabilized cell model was prepared usinga vacuolar perfusion technique. The cytoplasmic streaming remainedalmost normal after perfusion with EGTA medium (10 mM EGTA,40 mM PIPES, 5mM MgCl₂ and 800 mM sorbitol, pH 6.9), but stoppedwithin 10 min when saponin medium (EGTA medium plus 50 µg/mlsaponin, 50 µg/ml hexokinase and 5 mM glucose) was perfused.This model system was reactivated with a solution containing0.5 mM ATP and different concentrations of Ca²⁺ (reactivationmedium). With the reactivation medium at pCa 6–5, theresumed streaming lasted for about 10 min before the cytoplasmaggregated. At pCa 4–3, the streaming was observed onlyfor a few minutes because the cytoplasm aggregated quickly.At pCa 7, no reactivated movement was observed. Reactivationwas not induced in an ATP- or Mg²⁺-deficient medium even inthe presence of an adequate concentration of Ca²⁺, and was inhibitedby 50 µg/ml cytochalasin B or 1 mM N-ethylmaleimide. We concluded from these observations that the cytoplasmic streamingin Acetabularia is very likely to be driven by the actomyosinsystem in the presence of Mg-ATP and Ca²⁺ at pCa 6–5. (Received October 31, 1984; Accepted April 1, 1985)     

Assessing the biological significance of primary structure consensus patterns using sequence databanks. I. Heat-shock and glucocorticoid control elements in eukaryotic promoters

We describe FORTRAN 77 software allowing for convenient searchingof any segmented and ambiguous pattern in the currently availableprotein or nucleotide sequence databanks. For proteins, thissoftware can be instrumental in defining conserved functionaldomains among non–homologous overall primary structures.For nucleic acids, it is used in detecting complex and/or lowconsensus structural or regulatory patterns. As first applicationswe have studied the distribution of short consensus sequencesbelieved to characterize heat–shock and glucocorticoidregulated promoters. This analysis allowed an evaluation ofthe specificity, probable role and thus biological significanceof various regions of these consensus. In addition, the expressionof several known genes are predicted to be heat–shockor glucocorticoid sensitive. Received on March 25, 1985; accepted on March 28, 1985     

Computer program for prediction of the optimal and suboptimal secondary structures of long RNA molecules

We present an algorithm for prediction of RNA secondary structures.The program consists of three parts: the first computes locationand free energy of every possible stem–loop structure,the second computes probability of its formation, and the thirdlists the positions and free energies of all the stem–loopsin the order of their probability sizes. The circular RNA moleculeof chrysanthemum stunt viroid was used as an input data fordemonstrating the operation of the program. Received on March 14, 1985; accepted on March 18, 1985     

Comparison of Plasma Membrane and Tonoplast H+-Translocating ATPases in Phaseolus mungo L. Roots

Two membrane fractions were obtained from 16%/26% and 34%/40%interfaces following discontinuous sucrose density gradientcentrifugation of a 10,000–80,000xg pellet from mung bean(Phaseolus mungo L.) roots. The ATPases in the fractions differedfrom each other in their sensitivity toward various inhibitors,activation with salts, dependence of activity on pH, and K_mfor ATP.Mg²⁺. Judging from their sensitivity toward inhibitors,the ATPases in the low and high density membranes are consideredmainly of tonoplast and plasma membrane origin, respectively.Both ATPases were activated by gramicidin D and nigericin. ATP-inducedquenching of quinacrine fluorescence in both fractions requiredMg²⁺ and permeant anions such as Cl^– and quenching wascollapsed by carbonylcyanide p-trifluoromethoxyphenyl hydrazone.The sensitivities of quenching to the inhibitors were essentiallythe same as those of ATPase activity in the membranes. Thesefindings suggest the involvement of ATPases in H⁺-pumping acrossa plasma membrane and tonoplast. (Received April 12, 1985; Accepted October 11, 1985)     

Phototransformation of the Red-Light-Absorbing Form to the Far-Red-Light-Absorbing Form of Phytochrome in Pea Epicotyl Tissue Measured by a Multichannel Transient Spectrum Analyser

Phototransformation of the red-light-absorbing form (P_R) tothe far-red-light-absorbing form (P_FR) of phytochrome in 7-day-oldetiolated pea epicotyl hook segments was examined at 0.5C aftera red laser flash excitation using a multichannel transientspectra analyser with electrically gated photomultiplier. Effectsof a red laser pulse on the induction of phototransformationfrom P_R to P_FR were saturated at Ca. 15 mJ for flash wavelengthsof both 640 and 655 nm. The amount of P_FR induced by a saturatinglaser pulse was ca. 50% of that obtained at the photostationaryequilibrium. A difference spectrum measured 15 µs afterthe flash showed an absorbance increase at 697 nm and a decreaseat 663 nm. A difference spectrum determined 200 ms after theflash showed no such major absorbance increase. Kinetic analysisof the rapid absorbance decrease at 700 and 710 nm gave onesimple first-order reaction component having a rate constantof 2,500 s^–1. Kinetics of P_FR appearance measured by absorbanceincrease at 750 nm was resolved into three first-order reactionshaving rate constants of 5, 1.8 and 0.4 s^–1. The secondflash light of 710 nm given 2 µs and 2 ms after the firstred flash irradiation on P_R resulted in the formation of P_Rrather than P_FR. (Received February 8, 1985; Accepted April 11, 1985)     

Inverse Correlation of Thiol Proteinase with Nitrate Reductase Activities in Barley Leaves

Experiments conducted to determine the effects of leupeptin,a specific inhibitor of thiol proteinase, on extractable nitratereductase (NR) activity in leaves of Hordeum distichum duringdarkness revealed that leupeptin (0.01 mg.ml^–1) appliedto detached leaves significantly reduced the loss of NR activity.At the same time it also reduced the formation of small cytochromec reductase species, which is a degradation product of NR complex,Upon nitrate induction, extractable NR activity increased butthe content of thiol proteinase decreased. This inverse correlationwas also observed upon transfer of nitrate-grown barley seedlingsto nitrate-free nutrient solution. Furthermore, cycloheximide(0.1 mg.ml^–1) treatment of barley seedlings reduced thecontent of thiol proteinase and retarded the loss of NR activityunder noninducing conditions. These results suggest that invivo changes in NR content in leaves of Hordeum distichum arethe result of proteolysis by an endogenous thiol proteinase. (Received May 16, 1985; Accepted July 22, 1985)