Community metabolism on rocky-shore assemblages in a mesocosm: A. Fluctuations in production,respiration, chlorophyll a content and C:N ratios of grazed and non-grazed assemblages

Studies were undertaken with the aim of developing a standardized method for assessing environmental pollution in sediments by utilization of life-history data of freshwater tubificids. Similar bioassay methods have long been used for Daphnia magna, species of Ceriodaphnia and Nitocra, etc. in accordance with guidelines from the International Organization for Standardization (ISO). Tubifex tubifex was found to be the most likely candidate for such bioassays, since the species is readily kept in culture and reproduces more or less consistantly.The culturing method is slightly modified from Kosiorek (1974). This paper provides an example of the particular sensitivity of this kind of bioassay method in the detection of heavy metal contamination of lake sediments. Sediments from the oligotrophic Lake Runn were considered suitable for the purpose, since the lake receives waste water from a major mining industry in Sweden. Metal analyses of the sediments had revealed the agents likely to be causing the decreased biological activity measured in the lake; rough amplitudes for mercury: 800–3600 ng · g^-1 dw, copper: 800–1800 g · g^-1 dw, zinc: 3.3 – 8.1 mg · g g^-1 dw have been estimated for surficial sediments.Young tubificids exposed to Lake Runn sediments did not grow much and died off within a short period of time. No reproduction occurred. Sediments from Lake Runn, when mixed with sediments from the eutrophic Lake Hjälmaren, made reproduction of T. tubifex occur only in mixtures containing less than 50% L. Runn sediments. The growth rate, reproductive success and the very timing of consecutive reproductive events of cohort individuals were found to be highly indicative of toxic effects. When additional food sources were available, however, these effects were largely masked. Therefore, extra food rations were excluded from the original method.     

Evolution of the secondary haustoria to a primary haustorium in the parasiticScrophulariaceae/Orobanchaceae

In the parasiticScrophulariaceae andOrobanchaceae, two types of contact organs exist: secondary and primary haustoria. Secondary haustoria are lateral organs, developing in large numbers and only when the seedling is fully established. In contrast, a primary haustorium represents the first developmental stage of the seedling itself. In the root system of the parasiticLesquereuxia syriaca (=Siphonostegia syriaca) there are only secondary haustoria, but a few of them apparently develop in a terminal position. This is achieved by transferring the haustorial initiation region closer to the root apex. One can interpret this as a transformation of the apical meristem into a meristematic haustorial tissue. On the condition that an extreme shortening (abbrevation) of the primary root could happen, we discuss the transformation of the terminal secondary into a primary haustorium.     

Mutations in the E1a gene of type 5 adenovirus result in oncogenic transformation of Fischer rat embryo cells

Transformation of a specific clone of Fischer rat embryo (CREF) cells with wild-type 5 adenovirus (Ad5) or the E1a plus E1b transforming gene regions of Ad5 results in epithelioid transformants that grow efficiently in agar but that do not induce tumors when inoculated into nude mice or syngeneic Fischer rats. In contrast, CREF cells transformed by a host-range Ad5 mutant, H5hrl, which contains a single base-pair deletion of nucleotide 1055 in E1a resulting in a 28-kd protein (calculated) in place of the wild-type 51-kd acidic protein, display a cold-sensitive transformation phenotype and an incomplete fibroblastic morphology but surprisingly do induce tumors in nude mice and syngeneic rats. Tumors develop in both types of animals following injection of CREF cells transformed by other cold-sensitive Ad5 E1a mutants (H5dl101 and H5in106), which contain alterations in their 13S mRNA and consequently truncated 289AA proteins. CREF cells transformed with only the E1a gene (0-4.5 m.u.) from H5hrl or H5dl101 also produce tumors in these animals. To directly determine the role of the 13S E1a encoded 289AA protein and the 12S E1a encoded 243AA protein in initiating an oncogenic phenotype in adenovirus-transformed CREF cells, we generated transformed cell lines following infection with the Ad2 mutant pm975, which synthesizes the 289AA E1a protein but not the 243AA protein, and the Ad5 mutant H5dl520 and the Ad2 mutant H2dl1500, which do not produce the 289AA E1a protein but synthesize the normal 243AA E1a protein. All three types of mutant adenovirus-transformed CREF cells induced tumors in nude mice and syngeneic rats. Tumor formation by these mutant adenovirus-transformed CREF cells was not associated with changes in the arrangement of integrated adenovirus DNA or in the expression of adenovirus early genes. These results indicate, therefore, that oncogenic transformation of CREF cells can occur in the presence of a wild-type 13S E1a protein or a wild-type 12S E1a protein when either protein is present alone, but does not occur when both wild-type E1a proteins are present.     

Artifical diets and rearing of the nun moth, Lymantria monacha

Artificial diets were reviewed and two tested. The highest level of survival to the adult stage (72%) was obtained on a modified diet of Odell & Rollinson (1966). Rearing required 61 days for males and 70 days for females. Wing deformation occurred in 16% of the adults. The sex ratio ( : ) was 0.80. Average pupal weight was 281 mg for males and 368 mg for females. Females averaged 102 eggs (range 80–125 eggs). Neonates from field-collected egg masses started hatching on 6 December; frost was not necessary for hatching. Hatching could be postponed until at least 10 November of the following year by storing egg masses at-2°C. L. monacha can be maintained continuously in the laboratory.

---

Zusammenfassung Eine Massenvermehrung der Nonne, Lymantria monacha (L.), trat in 1984 auf 500 ha Pinus sylvestris bei Budelerbergen (S.O. der Niederlande) auf und betraf 1985 eine Fläche von 2800 ha. Obwohl die Vermehrung durch eine Luftapplikation mit Dimilin 25 bekämpft werden konnte, wurden Untersuchungen begonnen zur Entwicklung von für die Umwelt sicheren Bekämpfungsmethoden, besonders die Anwendung von Virosen. Das Ziel bestand in der Virusproduktion in künstlichen Raupenzuchten. Die Nonne wurde bisher mit verschiedenen für andere Insektenarten oder speziell für diesen Zweck entwickelten künstlichen Nährböden gezüchtet. Da die Zusammensetzung dieser Nährböden und die Zuchtmethoden nicht veröffentlicht waren und da wenige Details über die Raupenentwicklung vorlagen, wurden modifizierten Nährböden von McMorran sowie von Odell & Rollinson für die Massenzucht der Nonne geprüft.

     

Analyse,en olfactomètre tabulaire,de l'influence de différents stimulus olfactifs dans la recherche du partenaire sexuel par Zabrotes subfasciatus

Pour rechercher son partenaire sexuel Zabrotes subfasciatus doit utiliser les signaux olfactifs émis soit par les mâles ou par les femelles. Le pouvoir attractif de l'odeur des mâles et des femelles sont donc étudiés et comparés par olfactométrie. Le comportement de mâles et de femelles vierges et inséminées, mis en contact des graines de la plante hôte ou non, est observé en fonction de l'âge des imagos. En aucun cas, les odeurs des mâles n'exercent une attraction sur les femelles. Les femelles vierges en absence de graines de haricot (Phaseolus vulgaris) n'exercent pas d'attraction sur les mâles vierges. Par contre les odeurs des femelles vierges mises en contact avec les graines de haricot sont très attractives pour les mâles vierges et varie en fonction de l'âge: il est plus affirmé chez les femelles plus âgées. L'émission de la phéromone sexuelle est interrompue après l'insémination des femelles mais reprend au bout d'un certain temps après celle-ci.     

Respiration of the hydrogenosome-containing fungus Neocallimastix patriciarum

Mass spectrometric determinations of O₂ affinities by the rumen fungus Neocallimastix patriciarum indicated a stable respiration under liquid phase O₂ concentrations up to 10 M, the apparent K _m for O₂ under these conditions was 4.0 M. Exposure to O₂ concentrations in excess of 10 M resulted in rapid inactivation of the observed respiration. Calculated H₂ evolution rates for the organism are 8.1 nmol min^-1 per mg of protein. Exposure to liquid-phase O₂ concentrations in excess of 1.4 M caused 50% inhibition of H₂ production. That superoxide and peroxide are amongst the products of respiration was shown by the use of ESR spectroscopy with the spin trapping agent 5,5-dimethyl-l-pyrroline-N-oxide. An active superoxide dismutase was present, but catalase could not be detected.Abbreviations ESR electron spin resonance - DMPO 5,5-dimethyl-l-pyrroline-N-oxide - DETAPAC diethylene-triamine pentaacetic acid     

Contributions of basic neurochemistry towards a novel concept of epilepsy

Epilepsy is an ancient disorder which treatment over the centuries has been guided by preconceptions regarding its origin. The major improvements in epilepsy management came following the discovery of the EEG and the development of seizure suppressing agents. These advances in diagnosis and anticonvulsant therapy have further ingrained the conviction that epilepsy is a disease of neurons. Evidence presented here is intended to support a different point of view which suggests that the metabolic modifications in epileptogenic tissue denote subtle alterations in the anatomical and biochemical relationship between neurons and their glial envelopes. As a result the extracellular environment of these cells contain higher than normal levels of glutamic acid. This creates an unnatural functional connectivity between neurons so that they establish abnormal synchronous activity between them and become hyperexcitable due to the depolarizing milieu. To compensate for these biochemical changes it is suggested that some thought might be given to epilepsy management by metabolic manipulation. The measures should be directed specifically towards improving the ability of glia to remove glutamic acid from the extracellular milieu. Two obvious possibilities are to enhance glial glutamine synthesis and to improve the interstitial wash-out of glutamic acid in epileptogenic epicenters. Such a therapy would anticipate to gradually diminish seizure incidence and susceptibility without, however, having a direct action on convulsive episodes per se. The approach must be considered an adjunct to current epilepsy treatment and not a substitute for the use of anticonvulsants.Special Issue Dedicated to Dr. Abel Lajtha.     

Limiting factors for seed production in Cynoglossum officinale

Summary Over three years of study, small plants of Cynoglossum officinale consistently produced more flowers per unit of dry weight than large plants. In contrast to earlier results, weight of all seeds tended to increase more than proportional to size. As a result a positive correlation existed between seed set per flower and plant size. The correlation between the mean number of pollinator visits per flower and size was positive but not significant. In a field experiment we found that resources rather than pollen were limiting seed set. Thus, it is unlikely that enhanced pollination of the largest plants causes the size-dependency of seed set per flower. Alternative hypotheses are discussed briefly.Publication of the Meijendel Comité, New Series No. 96     

Acute phase response to recombinant interleukin-6 and macrophage- and fibroblast-derived crude cytokine preparations in primary cultures of mouse hepatocytes

A number of acute phase proteins were determined by electroimmunoassay in media from CBA mouse hepatocytes cultured for 2 days with human recombinant IFN beta 2/IL-6, as well as with conditioned media from LPS-stimulated rat macrophages, and of murine L fibroblasts. It was found that human recombinant IL-6 caused three-fold increase in secretion of fibrinogen, while haptoglobin, complement C3 and transferrin were increased respectively, to 168 per cent, 151 per cent, and 145 per cent of the control. DEX(10(-7) M) in DMEM supplemented with 5 per cent FCS, enhanced the IL-6 effect on the three positive acute phase proteins. IL-6 elevated haptoglobin mRNA in mouse hepatocytes to a degree comparable with the concentration of the protein in the culture medium. The effect of conditioned media from murine fibroblasts and peritoneal rat macrophages was generally similar to that of recombinant IL-6. However, both natural preparations of the cytokines caused decrease in albumin and alpha-1-proteinase inhibitor secretion.