Life histories ofNeomysis integer,and its copepod prey,Eurytemora affinis,in a eutrophic and brackish shallow lake

Data was collected on the population structure and fecundity of the mysidNeomysis integer and the calanoid copepodEurytemora affinis in Hickling Broad, a shallow and eutrophic brackish lake, over a two-year period 1988/89. Standing biomass and production rate estimates were made using estimates of size-specific dry weights and development times obtained from laboratory measurements, field observations and information found in the literature. Both mysid and copepod are capable of a rapid response to favourable conditions and have high rates of birth, growth and production.E. affinis reproduces throughout the year with an estimated annual (May 1988–May 1989) production of 20 g dry wt m⁻². Copepod standing biomass was less in 1989 compared with 1988 owing to an overall reduction in copepod body-size and a reduction of size at maturity. There was a suggestion from the data that this was caused by predation from a greater number of large (>9 mm body-length) mysids in 1989 compared with 1988.N. integer is highly seasonal in its growth with distinct peaks of recruitment in May and July. Annual (May 1988–May 1989) production of the mysid was estimated as 5.8 g dry wt m⁻². AlthoughE. affinis is the only available prey ofN. integer in the lake, the mysid population appears independent of changes in that of the copepod and probably avoids negative predator-prey feedback mechanisms owing to an ability to feed on epiphytic algae.     

Spring migration of Atlantic mackerel,Scomber scombrus,in relation to water temperature through Cabot Strait (Gulf of St. Lawrence)

Synopsis Sea surface temperatures across Cabot Strait (Gulf of St. Lawrence) ranged from 6 to 9°C on June 3, 1989, but only from 3 to 5°C on June 2, 1990. Periods of peak commercial landings of mackerel in eastern Cape Breton Island extended from May 22 to June 3 in 1989, and from May 28 to June 2 in 1990. In late May 1990, Atlantic mackerel were captured with a purse-seiner during exploratory fishing in Cabot Strait; commercial quantities were caught in water as cold as 2.8°C. The presence of mackerel in water a full 4°C colder than its reported lower tolerance limit indicates that the development of the 7°C isotherm is not a requirement for the vernal appearing of mackerel. The overlap of the periods of peak commercial landings between 1989 and 1990, despite: marked differences in warming chronology, suggests that the movements of mackerel are not as closely linked to water temperature as previously reported. The fish's thermal preferences could be subordinate to their reproductive requirements at this stage of their spawning migration.     

Changes in Levels of Auxin and Abscisic Acid and the Evolution of Ethylene in Squash Hypocotyls after Treatment with Brassinolide

Brassinolide stimulated an increase in fresh weight of segmentsof hypocotyls of etiolated squash (Cucurbita maxima Duch. cv.Houkou-Aokawaamaguri). Brassinolide-treated segments containedhigher levels of IAA than water-treated segments and also showeda tendency towards decreased levels of ABA. However, treatmentwith brassinolide did not have much effect on the productionof ethylene. (Received May 30, 1988; Accepted May 22, 1989)     

Predicting the summer chlorophylla concentration in a reservoir based on the environmental conditions of the preceding spring

From a monthly survey over a ten-year period (1983–1992) of the Ishitegawa Reservoir, Japan, two multiple regression equations describing the mean chlorophylla (Chl-a) concentration at 0.5 m depth during July, August and September (C _S ) and the maximum Chl-a concentration in the photic zone, including its subsurface maximum during this period (C _M ), were obtained. The conductivity at 0.5 m depth in May and the mean air temperature during May or during May and June were used as independent variables. These equations were calculated using seven years of data (1983–1988 and 1992). From 1989 to 1991 two impermeable plastic-coated sheet fences were installed across the upper end of the reservoir along the top 5 m of water column. The equations were used to determine the effectiveness of this flow regulation on the summer Chl-a concentration. In 1989 and 1991, when the fences were in place from June to August, no effects were found on the observed C _S and C _M values. In 1990, when the fences had been in place since October 1989, the observed values were lower than the predicted values.     

Correlation between environmental monitoring of thermophilic campylobacters in sewage effluent and the incidence of Campylobacter infection in the community

Environmental monitoring of thermophilic campylobacters in liquid sewage effluent (primary settlement only) during 1988 and 1989 showed a prominent seasonality with distinct peaks in May and June (the average number of bacteria per 100 ml of effluent in months other than May and June was 2244 and the average for the peak months was 50,778). Apart from September 1989, this seasonality coincided precisely with the seasonal variation of campylobacter enteritis in the community with similar distinct peaks in May and June (the incidence of infection in May and June was twice or three times that in the other months). Sampling of sewers showed that the campylobacters in the sewage effluent came mainly from abbatoir and animal processing plants with only a minor input from the community. Therefore, the seasonal peaks in the sewage effluent and in the community may not be dependent on human infections but on zoonotic infections which may also peak in May and June.     

Correlation between environmental monitoring of thermophilic campylobacters in sewage effluent and the incidence of Campylobacter infection in the community

Environmental monitoring of thermophilic campylobacters in liquid sewage effluent (primary settlement only) during 1988 and 1989 showed a prominent seasonablity with distinct peaks in May and June (the average number of bacteria per 100 ml of effluent in months other than May and June was 2244 and the average for the peak months was 50 778). Apart from September 1989, this seasonality coincided precisely with the seasonal variation of Campylobacter enteritis in the community with similar distinct peaks in May and June (the incidence of infection in May and June was twice or three times that in the other months).
Sampling of sewers showed that the campylobacters in the sewage effluent came mainly from abbatoir and animal processing plants with only a minor input from the community. Therefore, the seasonal peaks in the sewage effluent and in the community may not be dependent on human infections but on zoonotic infections which may also peak in May and June.     

Alterations of Plasma Membrane Phospholipids in Cultured Lavandula vera Cells Different in Cryoprotection by a Cryoprotectant Treatment

In highly cryoprotectable Lavandula vera cells, selected bya repeated freeze-thaw procedure, the degree of fatty acid unsaturationof plasma membrane phospholipids increased after treatment withdimethylsulfoxide-glucose mixture at 0?C for 2 h. The degreeof fatty acid unsaturation, in particular in phosphatidylethanolamineand phosphatidic acid did not increase in the unselected originalcells which were less cryoprotected by such treatment. (Received May 12, 1989; Accepted November 13, 1989)     

Spawning rhythms of common snook in Florida

Common snook Centropomus undecimalis were sampled monthly from the Jupiter–Lake Worth area of Florida's Atlantic coast during 1989 and 1991 (1452 fish) and from Tampa Bay on Florida's Gulf of Mexico coast during 1988 and 1989 (2090 fish). Group-synchronous oocyte development was demonstrated. Ovarian maturation began during March or April on both coasts. Spawning was first detected histologically in April during 1989 and 1991 on the Atlantic coast and during May in 1988 and in April in 1989 on the Gulf coast. In each year, spawning ended during October on the Atlantic coast and during September on the Gulf coast. Ovarian histological evidence suggested that individual females may spawn every 1·1–2·5 days between 1400 and about 2000 hours. Final oocyte maturation occurred independently of either tidal cycle or lunar phase, and some common snook were observed in prespawning or spawning condition on every day sampled. Spawning occurred in or near major inlets to the Atlantic Ocean and the Gulf of Mexico, in secondary passes to larger inland bays and bayous, and around nearshore islands.     

Feeding habits of raccoon (Procyon lotor) (Carnivora: Procyonidae) in a coastal,tropical wet forest of Costa Rica

Raccoon (Procyon lotor) food habits were studied at Manuel Antonio National Park, a tropical rain forest in the Pacific coast of Costa Rica from May to December 1987, from September to December 1989 and from January to April 1990. A 134 feces sample size was used to assess the most important items in raccoon diet: two crab species (Gecarcinus quadratus and Cardisoma crassum) with a relative frequency of 0.94 in the rainy season of 1987, 0.76 in the rainy season of 1989 and 0.65 in the dry season of 1990. Fruits were the second category in importance, with relative frequencies of 0.09 for 1987, 0.32 for 1989 and 0.44 for 1990.     

Lothar Geitler on the occasion of his 90th birthday on May 18th 1989

Ohne Zusammenfassung

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Lothar Geitler on the occasion of his 90^th birthday on May 18^th 1989

     

HCABAND: A computer program for the 2D-helical representation of protein sequences

A BASIC program, HCABAND, is described which is used to convertthe linear amino acid sequence of proteins into a word processor-readablefile to generate the 2D-helical representation required forhydrophobic cluster analysis. The user can specify the widthof the plot and can use the word processor macro-commands tofacilitate visual inspection of the plots. The plots can beeasily stored on diskettes, mixed with text and printed. HCABANDfeatures are generally applicable and can be implemented onvirtually any microcomputer. Received on May 9, 1989; accepted on August 28, 1989     

A computational procedure for assessing the significance of RNA secondary structure

In our recent series of papers, we have used the structuresof statistical significance from Monte Carlo simulations toimprove the predictions of secondary structure of RNA and toanalyze the possible role of locally significant structuresin the ljfe cycle of human immunodeficiency virus. Because ofintensive computational requirements for Monte Carlo simulation,it becomes impractical even using a supercomputer to assessthe significance of a structure with a window size > 200along an RNA sequence of 1000 bases or more. In this paper,we have developed a new procedure that drastically reduces thetime needed to assess the significance of structures. In fact,the efficiency of this new method allows us to assess structureson the VAX as well as the CRAY Received on May 11, 1989; accepted on August 22, 1989     

The Biosynthesis of Indole-3-acetic Acid from D-tryptophan in Alaska Pea Plastids

IAA biosynthesis in Alaska peas is shown to be plastid localized.D-tryptophan is a much better substrate than is L-tryptophan,and IAA production is dependent on a keto acid. In line withthis, a plastid localized D-tryptophan aminotransferase hasbeen found and purified 1,500 fold. The enzyme has no activitywith L-tryptophan and prefers pyruvic or oxaloacetic acid asan amino group acceptor. Activities are much higher in darkthan in light grown tissues. Some possible physiological ramificationsare discussed. (Received May 15, 1989; Accepted July 25, 1989)     

Reproductive biology ofAwaous guamensis, an amphidromous Hawaiian goby

Synopsis Spawning season, size at first reproduction, oocyte maturation, and fecundity ofAwaous guamensis, an amphidromous Hawaiian goby, were studied from June 1989 through May 1991 in the Wainiha River, Kau'ai, Hawai'i. Female fish larger than 73 mm standard length (SL) had mature gonads from August through December in 1989 and 1990. Gonadosomatic index (GSI) values for mature females ranged from 0.2 to 14.5 during the spawning season. Male fish larger than 64 mm SL had elevated GSI values from June 1989 through December 1989 and from August 1990 through December 1990. Mature sperm were found in two male fish collected in January and February. GSI values for mature males ranged from less than 0.01 to 4.0 in the spawning season. Size-frequency distributions of measurements of vitellogenic oocyte diameters and microscopic observations of oocytes indicated this species has group-synchronous oocyte development. Ovarian maturation stages examined over a 29-month period suggest that members of the stock spawned at different times within the spawning season, although mass spawning events have been documented for this species. Estimates of clutch sizes from nests measured in situ were comparable to estimates of potential fecundity from in vitro examination of ovaries, and indicated that female fish deposited an entire clutch during a spawning event. No evidence for multiple spawning by an individual fish in a single season was found. However, microscopic observations of brown bodies in some ovaries suggested that individual fish probably spawn more than once in a lifetime.     

Increases in Cyanide-resistant Respiration and Ethanol Fermentation in Rice Callus Cells with Increases in the Supply of Sucrose

Cyanide-resistant respiration and ethanol fermentation appearto proceed in parallel in rice callus cells cultured under aerobicconditions. Both the production of ethanol and the rate of CN-resistantrespiration were increased with increases in the concentrationof sucrose in the culture medium, but the activity of the cytochromepathway was scarcely affected. (Received May 23, 1988; Accepted February 9, 1989)     

Methods for discovering novel motifs in nucleic acid sequences

We describe a computer tool to aid the discovery of new motifsin nucleic acid sequences. A typical use would be to analysea set of upstream regions from a family of related genes inorder to find possible control sequences. The heart of the methodis the creation of dictionaries of related subsequences. Thesedictionaries can then be analysed to look for the commonestor best-defined subsequences, those that occur in the highestnumber of different sequences, or for those in equivalent positionswithin the family. We show the application of the method toa set of E. coli promoter sequences. Received on May 9, 1989; accepted on July 27, 1989     

海南岛热带山地雨林短期水量平衡及主要养分的地球化学循环研究

本文采用集水区技术和定位研究方法,利用１９８９年５月至１９９３年４月４ａ的观测资料,对海南岛尖峰岭热带山地雨林天然更新林的水量平衡及主要养分的地球化学循环规律进行了分析。     

Circular Arrangement of Cortical F-actin around the Subapical Region of a Tip-Growing Fern Protonemal Cell

F-actin organization in the tip-growing cells of fern protonematawas investigated by rhodamine-phalloidin staining in two species:Adiantum capillus-veneris and Pteris vittata. Circular arrangementof cortical F-actin was found around the subapical region ofprotonemal cells in both species. In rhizoids, such structureswere absent and the axial filaments appeared to fan out fromthe tip. (Received May 22, 1989; Accepted September 6, 1989)     

SIMFIT: a microcomputer software-toolkit for modelistic studies in biochemistry

A software package suitable for personal computers and designedto handle simulation and fitting problems related to the studyof biomolecules under pre-steady and steady state conditionsis presented, and its overall architecture as well as the implementedalgorithms illustrated. The peculiar features of the packageare: (i) integrated capability of simulating dynamic modelsand fitting to them experimental data; (ii) handling of stiffproblems; (iii) free use of algebraic as well as differentialequations; (iv) objective comparison of models of differentcomplexity. The above features are discussed through a numberof examples taken from the direct experience of the authorsin enzyme kinetics and ligand binding. Received on May 23, 1989; accepted on August 21, 1989     

Waiting times for nursing-home placement: the impact of patients' choices.

OBJECTIVE: To identify patient characteristics and characteristics of long-term care facilities that significantly affect the waiting time for transfer from hospital to nursing home. DESIGN: Cohort study. PARTICIPANTS: All patients designated to be transferred from four Winnipeg hospitals between June 1, 1988, and May 31, 1989. The patients were followed up until placement, death or May 31, 1990. MAIN OUTCOME MEASURE: Length of time waiting for nursing-home placement and relative rates of placement. RESULTS: The variable found to shorten the waiting time the most was the patient''s choice of a for-profit or nonprofit secular facility; other significant variables were male sex, age of 75 to 84 years and occupancy of an acute care bed during the wait. CONCLUSION: The province has three policy options: it can increase the proportion of secular nursing-home beds when new facilities are built; it can require that hospital patients accept an interim nursing-home placement pending transfer to the nursing home of their choice; or it can tie the sponsorship of new facilities to a formula based on the ethnoreligious distribution of the population currently aged 55 to 64 years.