Inter-and intraspecific differences in fatty acid composition of freshwater crustacean zooplankton

1. The composition of fatty acids (FA) from C14 to C18 was measured for edible seston and for individual Daphnia galeata , Diaphanosoma brachyurum and Eodiaptomus japonicus from Lake Biwa using a pyrolysis–gas chromatography (Py–GC) method. Based on the relative abundance of the FA, inter-and intraspecific differences in composition were examined.
2. Among the FA, C16 : 0 was the most abundant, both in the three zooplankton species and in edible seston smaller than 20 μm, suggesting that the composition of the zooplankton was roughly reflected by their diet. However, the abundance of C18 : 1 relative to C16 : 1 and C18 : 0 was much higher in each zooplankton species than in the diet.
3. Comparison of the relative abundance of FA among the three zooplankton species revealed that intraspecific differences in FA composition are greater than interspecific differences. These results indicate that variability in FA composition is not necessarily species-specific, and can be obscured by variation in composition between individuals.     

Isolation of the Antheridiogen of Anemia phyllitidis

The antheridiogen (antheridium-inducing substance) of the fern species Anemia phyllitidis has been obtained in pure form based on the isolation procedure described below. Pure antheridiogen is active to a dilution of 10 μg/l in antheridium formation and 0.3 μg/l in dark-germination. Its molecular formula is C₁₉H₂₂O₅.     

Structure of a New Pyrimidine from <Emphasis Type="Italic">Bacillus subtilis</Emphasis> Phage SP-15 Nucleic Acid

THE unusual modified base¹ of the nucleic acid of the large, generalized transducing phage of Bacillus subtilis SP-15 was predicted from the low denaturation temperature of the native nucleic acid. The base was detected as a fifth ultraviolet-absorbing component once the nucleic acid had been hydrolysed with formic acid; it partially replaces the thymine and represents 12 mol per cent of all the bases¹. It is responsible for the low Tm of the nucleic acid, since once all other unusual components have been removed, the remaining material melts at the same temperature as the native nucleic acid. We report here the isolation and characterization of this new pyrimidine.     

Modelling the effects of dams on freshwater fish distributions in Hokkaido, Japan

1. We examined the effects of habitat fragmentation caused by dams on freshwater fish species using a database of 7848 fish presence/absence surveys, conducted between 1953–2003 in Hokkaido, Japan. 2. A series of generalised linear models showed that for 11 of 41 taxa examined, the probability of occurrence had been influenced either negatively (eight taxa) or positively (three taxa) by the presence of a dam downstream from their habitat. 3. Maps of modelled predictions revealed that dams had had widespread negative impacts on certain taxa, while for other taxa the impact was limited to specific basins. Two of the three taxa whose probability of occurrence was increased in areas above dams have long been transplanted into reservoirs in Japan. 4. For four of the eight taxa whose probability of occurrence was reduced above dams and all three taxa whose probability of occurrence increased above dams, the temporal length of habitat isolation (i.e. the number of years between dam construction and sampling) was also a significant predictor of the probability of occurrence. This pattern indicates that these taxa experienced a gradual rather than an instantaneous population impact as a result of dam construction. 5. The eight taxa whose probability of occurrence was reduced as a consequence of dams all exhibit migratory life cycles. Although migratory taxa are probably more susceptible to the negative effect of dams, we could not detect significant relationships between migration life histories and the effect of fragmentation by dams. 6. These analyses enable stream and fisheries managers to quantify the impacts of habitat fragmentation because of dams for individual species. The spatially explicit nature of our analyses also enables identification of the areas of the impact at broad geographical scales. Using our results, managers can take effective conservation and restoration measures to predict, mitigate or remove the impact of dams. For example, our results can be used to prioritise dams for removal or to predict losses of biodiversity and ecosystem services in advance of dam construction.     

Portulal: a rooting promoting substance in Portulaca leaves

A new bioassay which employs disbudded epicotyl cuttings takenfrom light grown Azukia seedlings (A. angularis) was devisedfor testing rooting promotion activity. By use of this method,the rooting promoting principle in leaves of Portulaca grandiflorawas isolated and identified with portulal which had been previouslyobtained. Portulal was reported as an inhibitor of rooting inetiolated Raphanus cuttings and has recently been determinedto be a bicyclic diterpene containing a perhydroazulene nucleus.Portulal promoted the adventitious root formation in severalkinds of plants, i.e. Azukia angularis, Vigna Catiang var. sinensis,Phaseolus Mungo and Raphanus sativus var. acanthiformis ‘Risodaikon’. The rooting process in Azukia and Raphanus cuttings seems toinclude at least two phases; a "preparatory phase" or a portulal-and gibberellin-sensitive phase and a "main phase" or an auxin-sensitiveand portulal-insensitive phase. ¹Contribution No. 16 from the Botanical Gardens, Faculty ofScience, University of Tokyo, Tokyo, Japan. (Received April 3, 1969; )     

INTERACTION BETWEEN HELIANGINE AND PYRIMIDINES IN ADVENTITIOUS ROOT FORMATION OF PHASEOLUS CUTTINGS

1. Heliangine at 110^–4 M promoted the adventitious rootformation in hypocotyls of cuttings taken from light-grown (1,900lux) Phaseolus mungo seedlings. The promotion was almost completelyreversed by 310^–4 M uracil, uridine, cytidine, oroticacid or 610^–4 M carbamoyl DL-aspartic acid, and partlyby 310^–4 M thymine or thymidine. Neither 310^–4M cytosine, adenine, adenosine, guanine, guanosine nor a combinationof 310^–4 M carbamoyl phosphate and 310^–4 M L-asparticacid reduced the promotion by heliangine.
2. Uracil did not reducethe inhibiting effect of heliangine onthe indoleacetic acidinduced elongation of etiolated Avenacoleoptile sections.
3. Helianginein an aqueous uracil solution was recovered unchangedafter24-hr incubation at room temperature.
4. The root formation ofPhaseolus cuttings was promoted also by2-thiouracil and 5-fluorouracil.The effect was reversed byorotic acid or carbamoyl asparticacid, but not by carbamoylphosphate plus aspartic acid.
5. Ribonucleaseat 100 µg/ml increased the number of rootsprotruded fromhypocotyls of cuttings by about 260%.
6. A possible interpretationfor the promotion of root formationby heliangine is offered.

¹ Contribution No. 15 from the Botanical Gardens, Faculty ofScience, University of Tokyo, Tokyo, Japan. ² Dedicated to Prof. Dr. H. SODING in commemoration of the 70thbirthday.     

CHLOROPHYLL AMOUNT AS AN INDICATOR OF MATTER PRODUCTIVITY IN BIO-COMMUNITIES

The data of chlorophyll amounts in diverse bio-communities arecompiled and discussed with reference to matter production. The chlorophyll amount in euphotic zone of lakes and oceanswas less than 1 g/m², mostly less than 0.1 g/m². In phytoplanktonblooms it was ca. 0.1–1 g/m². Large values of 5–20g/m² were obtained in the outdoor mass cultures of Chlorella,in which the high population density and chlorophyll contentof the alga were observed. In terrestrial higher plant communitiesthe chlorophyll amount (ca. 1–10 g/m²) was usually higherthan in aquatic phytoplankton communities. The largest (13.3g/m²) was obtained with an evergreen gallery forest in Thailand.The chlorophyll amount of desert bio-community could be expectedto be as high as that in water blooms. The maximum chlorophyll amount in bio-communities seems to attainup to 20 g/m² when the conditions are favorable. ¹ Dedicated to Prof. H. TAMIYA on the occasion of his 60th birthday. (Received December 25, 1962; )     

A stress‐inducible sulphotransferase sulphonates salicylic acid and confers pathogen resistance in Arabidopsis

Sulphonation of small molecules by cytosolic sulphotransferases in mammals is an important process in which endogenous molecules are modified for inactivation/activation of their biological effects. Plants possess large numbers of sulphotransferase genes, but their biological functions are largely unknown. Here, we present a functional analysis of the Arabidopsis sulphotransferase AtSOT12 (At2g03760). AtSOT12 gene expression is strongly induced by salt, and osmotic stress and hormone treatments. The T‐DNA knock‐out mutant sot12 exhibited hypersensitivity to NaCl and ABA in seed germination, and to salicylic acid (SA) in seedling growth. In vitro enzyme activity assay revealed that AtSOT12 sulphonates SA, and endogenous SA levels suggested that sulphonation of SA positively regulates SA production. Upon challenging with the pathogen Pseudomonas syringae, sot12 mutant and AtSOT12 over‐expressing lines accumulate less and more SA, respectively, when compared with wild type. Consistent with the changes in SA levels, the sot12 mutant was more susceptible, while AtSOT12 over‐expressing plants are more resistant to pathogen infection. Moreover, pathogen‐induced PR gene expression in systemic leaves was significantly enhanced in AtSOT12 over‐expressing plants. The role of sulphonation of SA in SA production, mobile signalling and acquired systemic resistance is discussed.     

Ovarian development and vitellogenesis in the sawfly,Athalia rosae ruficornis Jakovlev (Hymenoptera,Tenthredinidae)

Summary

Ovarian development in Athalia rosae ruficornis Jakovlev (Hymenoptera: Tenthredinidae) is described. Number of nurse cells per egg chamber is most often around 60 (close to 63 according to the 2ⁿ–1 rule), but in many cases it deviates from this number significantly. Two major yolk proteins [vitellins: large (apparent molecular weight 160–170 kD) and small (48–50 kD] were identified by SDS-PAGE. Western blotting and immunochemical detection using polyclonal antibodies prepared against each of the vitellins revealed that adult female but not male (both haploid and diploid) hemolymph contains vitellogenins corresponding to these vitellins. Vitellogenins become detectable in the hemolymph of late pupae, and vitellins one day later in the oocytes of adults. Transplantation of immature ovaries into the adult male abdomen caused not only significant accumulation of vitellins in the oocyte but also appearance of small amounts of hemolymph vitellogenins in host males. Injection of homogenate of immature ovaries also caused appearance of small amounts of hemolymph vitellogenins in host males.