bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesen von 3‐Hydroxy‐4‐methyl‐3‐cyclobuten‐1,2‐dion (Methylmoniliformin)
Authors: Bellus Daniel , Martin Pierre , Sauter Hanspeter , Winkler Tammo
Published: December 2004

Syntheses of 3‐Hydroxy‐4‐methyl‐3‐cyclobutene‐1,2‐dione (Methylmoniliformin)

New routes to 3‐hydroxy‐4‐methyl‐3‐cyclobutene‐1,2‐dione(9), the lowest homologue of the mycotoxine moniliformin are described. A common feature of all pathways is the synthesis of methylcyclobutanes having the oxidation level 6. Precursors, which are easily transformed to9by acid catalyzed hydrolysis, include [2+2]‐cycloadducts ofin situgenerated methyl ketene to tetraethoxyethylene and [2+2]‐photocycloadducts of dichlorovinylenecarbonate with 1,1‐dichloro‐1‐propene. The acid hydrolysis of [2+2]‐cycloadducts of chlorotrifluoroethylene toN, N‐diethyl‐1‐propynylamine yields the diethylamide of9 (=22)in 50% overall yield. In addition, a convenient one‐pot‐two‐steps synthesis of a new electronrich ethylene, 1,1,2‐triethoxy‐2‐trimethylsilyloxy‐ethylene(11), is described.
Stoffwechselprodukte von Mikroorganismen 198. Mitteilung Die Eurekansäure, ein Abbauprodukt von Flambamycin und Avilamycin: Konfigurationsbestimmung durch Röntgenstrukturanalyse und Abbau
Authors: Kupfer Ernst , Neupert‐Laves Katarina , Dobler Max , Keller‐Schierlein Walter
Published: December 2004

Eurekanic Acid, a Degradation Product of Flambamycin and Avilamycin: Determination of the Configuration by X‐Ray Structural Analysis and Degradation

The relative configuration of methyl O‐acetyleurekanate (6), obtained by mild methanolysis of avilamycin A (2) and subsequent acetylation, was determined by an X‐ray structural investigation. Methyl dihydroeurekanate (7), similarly obtained from avilamycin C (3) and from reduced avilamycin A methyl ether, was degraded to L‐threonolactone (14) which allowed to determine the chirality of eurekanic acid (4).
The Photochemistry of 5,6‐Dimethylidene‐2‐norborananone. Synthesis and Diels‐Alder Reactivity of 2,3‐Dimethylidenebicyclo‐[2.1.1]hexane
Authors: Schwager Luis , Vogel Pierre
Published: December 2004

2,3‐Dimethylidenebicyclo [2.1.1]hexane (4) was isolated from direct irradiation (253.7 nm) of 5,6‐dimethylidene‐2‐norbornanone (3). Quenching experiments at 253.7 nm, as well as direct and sensitized irradiations at >300 nm suggested that a high vibrationally excited S1‐ or a S2‐state is required for the photodecarbonylation of 3 in contrast with other β, γ‐unsaturated ketones for which α‐cleavage occurs with lower excitation‐energy. The new diene 4 reacted toward tetracyano‐ethylene (k (1mol−1 s−1))=(3.1±0.34) · 10−3) in toluene and (6.2±0.11) · 10−3 in benzene only 60 times more slowly than 2,3‐dimethylidenenorbornane (5) and ca. 850 times as fast as 2,3‐dimethylidene‐syn1,4,5,6‐tetramethylbicyclo[2.1.1]‐hexane (9).
Préparation de dérivés de sucres acétyléniques terminaux et d'acides ynuroniques par réaction de Wittig. Note de laboratoire
Authors: Tronchet Jean M. J. , Bonenfant Alain P. , Perret Françoise , Gonzalez Alberto , Zumwald Jean‐Bernard , Martinez Ernesto M. , Baehler Bruno
Published: December 2004

Synthesis of Terminal Acetylenic Sugars Derivatives and Ynuronic Acids Derivatives by Use of a Wittig Reaction

The method described for the preparation of terminal acetylenic sugars presents two advantages over earlier procedures: no new asymmetric center is created and the chain can be extended by one or more C‐atoms. The method also allows preparation of ynuronic acids. The aldehydosugars derivatives 1–7 gave in good to excellent yields the corresponding gem‐dibromoenoses 8–14 from which either the terminal acetylenic sugars derivatives 15–21 or the ynuronic acids 22–24 were easily prepared. A few examples of 1,3‐dipolar cycloadditions (leading to 28–30) with these acetylenic sugar derivatives are also described.
On the Use of N, N′‐Dipyrrolylmethane in Heterocyclic Synthesis. Dipyrrolo [1,2c:2′, 1′e]‐2 H‐imidazole and its Aromatic Anion
Authors: Burger Ulrich , Dreier Francine
Published: December 2004

The pyrrolate ion (5) is shown to produce N, N′‐dipyrrolyl methane (4) when reacted with dichloromethane under conditions of weak counter‐ion association. 1‐Azoniafulvene ion (13) is suggested to be the key intermediate in this reaction. N, N′‐Dipyrrolyl methane (4) undergoes intramolecular oxidative coupling when treated with butyllithium and Cu(II)chloride, yielding the novel ring system of dipyrrolo [1,2c: 2′, 1′e]‐2 H‐imidazole (3). The latter upon reaction with methyl lithium forms the Hückel‐aromatic anion 2. Solutions of the lithium salt are stable for several days. Reaction of the dianion of 2,2′‐bipyrrole (11) with dichloro‐methane does not produce 3, but a pyrrolophane‐type dimer (12) having its two anticoplanar N, N′‐bipyrrolediyl subunits arranged in a double layer and joined by a methylene group on each side.
Wasserstoff/Deuterium‐Isotopeneffekte bei Europium‐Verschiebungsexperimenten and Allencarbonsäureestern
Authors: Lang Robert W. , Hansen Hans‐Jürgen
Published: December 2004

Hydrogen/Deuterium Isotope Effects on Europium Induced Chemical Shifts of Allenic Esters

It is shown by 1H‐NMR. experiments, that in the presence of europium shift reagents, mixtures of allenic esters and their partially deuterated counterparts give rise to α‐, β‐, γ, and δ‐H/D isotope effects (cf. Table and Fig. as well as formula 6 for assignment). The measured effects (0.4 to 2.2%) are mainly attributable to C, H/C, D bond length differences which influence the complexation constant between the shift reagent and the substrate as well as the s‐cis/s‐trans conformational equilibrium of the allenic esters.
Halochrome Molekeln 2. Mitteilung [1] Synthese und acidobasisches Verhalten substituierter 6,6‐Diphenyl‐6H‐chromeno [4,3‐b]indole
Authors: Gunzenhauser Sigmund , Balli Heinz
Published: December 2004

Halochromic Molecules, Synthesis and Acidobasic Behaviour of Substituted 6,6‐Diphenyl‐6H‐chromeno [4,3‐b]indoles

Substituted 6,6‐diphenyl‐6H‐chromeno [4,3‐b]indoles are forming with acid ring‐opened, intensely coloured diphenyl‐indol‐3‐yl‐carbenium salts. The preparation of these products is described and the UV./VIS.‐spectra are discussed. An investigation of the halochromic properties is made by spectrophotometric determination of ϵpH*‐ and ϵH0*‐curves in buffered methanol/water solutions. pK*‐ and pK*‐values respectively are calculated and the suitability of substituted 6 H‐ chromeno [4, 3‐b]indoles as chromogens in self‐duplicating stationery is discussed.
The Adamantane Rearrangement of 1,2endo‐Trimethylenenorbornane. Preliminary communication
Authors: Klester Alfred Michael , Josef Jäggi Franz , Ganter Camille
Published: December 2004

1,2endo‐Trimethylenenorbornane (1) in the presence of aluminium bromide in carbon disulfide at −60° isomerizes at a much higher rate than its 2exo‐isomer 2 to 2endo, 6endo‐trimethylenenorbornane (3) as the sole product. By consequence, the hydrocarbon 2 being the next intermediate in the sequence of the adamantane rearrangement of 1 seems to be very unlikely.
Laser‐Induced Luminescence of Flavinium Salts
Authors: Visser Antonie J. W. G. , Van Hoek Arie , Müller Franz
Published: December 2004

Flavinium salts dissolved in an ethanolic glass exhibit blue fluorescence and orange‐red phosphorescence upon excitation with a UV. line from an argon ion laser equipped with UV. optics. This arrangement enables the wavelength distribution and the time‐dependence of the phosphorescence to be measured in a relatively short time. Four cationic flavins were investigated. In spite of the small difference in the chemical structure of the compounds studied, large differences in the spectral shapes and in the ratio of quantum efficiencies of phosphorescence and fluorescence became apparent. The phosphorescence lifetimes were of the same order of magnitude, which indicated a similar rate of depletion of the lowest excited triplet state for all four cations. However, the efficiency of triplet formation (intersystem crossing) is affected by slight structural modifications in the pyrimidine subnucleus of the flavinium salt. The results point to a possible role of vibronic spin‐orbit coupling in the intersystem crossing.
A novel pesticide‐induced conformational state of the oestrogen receptor ligand‐binding domain, detected by conformation‐specific peptide binding
Authors: Sumbayev Vadim V. , Bonefeld-Jørgensen Eva C. , Wind Troels , Andreasen Peter A.
Published: December 2004

The diverse effects of different natural and synthetic oestrogen receptor ligands depend on induction of different receptor conformations, allowing differential interactions with other transcription factors. Different conformations of the oestrogen receptor ligand binding domains can be monitored by conformation‐specific binding to peptides selected from phage‐displayed peptide libraries. We now report that a group of chlorinated pesticides, including 2,4‐dichlorodiphenyl‐dichloroethylene, induces a peptide recognition pattern different from those induced by any one of the classical oestrogen receptor ligands. The pesticide‐complexed oestrogen receptors recognized peptides reacting with the receptors complexed both with the natural oestrogen 17β‐oestradiol and with the synthetic partial antagonist 4‐hydroxy‐tamoxifen, respectively, indicating that the pesticide‐induced conformation shares features with both the 17β‐oestradiol‐ and the 4‐hydroxy‐tamoxifen‐induced conformations. The substitution H524A in the ligand binding domain conferred the pesticide‐specific peptide recognition pattern and transactivation activity to the oestradiol‐ and the 4‐hydroxy‐tamoxifen‐complexed receptors, indicating that one important determinant of the pesticide‐induced conformation is a lack of stabilisation of any one particular receptor conformation by ligand interaction with H524, which is known to interact with both oestradiol and 4‐hydroxy‐tamoxifen. Thus, peptide binding analyses of oestrogen receptor conformations induced by environmental endocrine disruptors can give novel information about molecular mechanisms of oestrogen action in general.
Spectroscopic requirements for Raman instrumentation on a planetary lander: potential for the remote detection of biosignatures on Mars
Authors: Jorge Villar S.E. , Edwards H.G.M.
Published: December 2004

The special characteristics of Raman spectroscopy (relative insensitivity to water, non-destructive detection, sensitivity to bio- and geosignatures, molecular structural composition information, etc.) together with the development of miniaturized Raman spectrometers make the consideration of this technique for future robotic landers on planetary surfaces, particularly Mars, a very interesting option. The development of light and rugged Raman spectrometers limits the possible scope of the instrumentation which has particular importance in the recognition of biomolecular and mineral signatures. In this work, we evaluate the spectral resolution and scan time parameters and the effect that they have on the Raman spectra of extremophilic biomolecules, together with the wavenumber ranges which are critical for the detection of life signals. This is of vital relevance for the design of miniaturized Raman spectrometer systems. From our results, we conclude that for extraterrestrial biological signatures unambiguous Raman spectral identification provided with a minimum of 16 cm−1 spectral resolution is required for the most significant biosignature wavenumber range in the 1700–700 cm−1 region.
Characterization and critical testing of potential microfossils from the early Earth: the Apex ‘microfossil debate’ and its lessons for Mars sample return
Authors: Brasier Martin D. , Green Owen R. , McLoughlin Nicola
Published: December 2004

The importance of the search for life within the universe underpins many of the objectives of ESA and NASA. Fundamental to this objective is the recognition and understanding of the early fossil record on planet Earth. The history of study of ‘microfossils’ from the 3465 Ma Apex cherts of the Warrawoona Group in Western Australia is reviewed, as are the criteria put forward to test for for biogenicity of early microfossils. We propose that the null hypothesis of an abiotic or prebiotic origin of ancient microscopical artefacts is sustained until mutually supporting, contextural morphological and geochemical evidence for a biological origin is presented and an abiotic origin is falsified.
Magmatic carbon in Martian meteorites: attempts to constrain the carbon cycle on Mars
Authors: Grady M.M. , Verchovsky A.B. , Wright I.P.
Published: December 2004

One of the current goals of Martian exploration is to find evidence for extinct (or even extant) life. Carbon (an essential ingredient of life on Earth) is known to occur on Mars as CO2 in the atmosphere and frozen in the polar caps; it is inferred to be present as carbonates in the Martian crust and soils. We are attempting to define and quantify the different carbon reservoirs on Mars, so that we can follow Mars' carbon cycle. This paper discusses a primordial magmatic component that could be the starting point of such a cycle. The nature, distribution and isotopic composition of carbon was measured in a suite of Martian meteorites, comprising Chassigny and 11 shergottites. Other Martian meteorites were not included, as they sample rocks that have been altered by fluids at Mars' surface. Our results, obtained by high-resolution stepped combustion and mass spectrometry, show that the magmatic component has a very variable abundance of 1–100 ppm, with δ13C~−20±4‰. This value is close to magmatic carbon determined for Moon and for Vesta (the parent body of the HED basaltic meteorites), but very different from that of Earth.
A postulate to assess ‘habitability’
Authors: Cockell Charles S. , Westall Frances
Published: December 2004

One principal challenge in biology is defining a postulate by which the habitability of other planets can be assessed. Current assessments suffer from two potential weaknesses. With respect to other planets, either assumptions are made about the physical and chemical conditions of environments that err on the side of biological optimism without empirical constraint by spacecraft observations or novel physiologies of microorganisms are invented to fit extraterrestrial environmental conditions with no demonstrated microbiological counterparts on Earth. Attempts to assess the habitability of the early Earth suffer from similar problems. We discuss the following postulate: ‘the proposition that a planet is or was habitable requires that the physiological requirements of microorganisms on Earth known at the time of assessment match the empirically determined combined physical and chemical conditions in the extraterrestrial or early Earth environment being assessed’ as a means of evaluating ‘habitability’. We use as tests for our postulate the early Earth and the cloud deck of Venus (a habitat that has been a source of optimistic debate for forty years). We conclude that, although the early Earth was habitable, Venus is a dead world.
Broad horizons – SETI, SF and education
Authors: Griffiths Martin
Published: December 2004

Science fiction (SF) is often perceived as a ‘fringe’ form of entertainment that excites the socially challenged. This misperception detracts from the critical, scientific and interpretive nature of the genre which can be directed into science teaching at school and university levels as an innovative way of exploring the cultural background, politics, leitmotif and themes of society, science and their operation. One example is the ‘alien’ theme in SF; it is perceptually one of the driving factors in the search for extraterrestrial intelligence (SETI). Such a topic can become an introduction to current technology, the motives and politics of science and the sociological implications inherent in a confrontation with the ideal of man's uniqueness in the cosmos. When applied to the SETI, SF engenders a constructive convergence in studies such as biological determinism, the evolution of life, communication, interstellar travel and methods of contact, thus enriching the consideration of possible life in the cosmos. Adopting elements of SF in lifelong learning therefore enables informed, imaginative reflection and debate that educates, trains and instructs, broadening the potential of students and their future roles by invoking an analysis of vital public, scientific and humanistic fields.

Imagination lies at the basis of all discovery

Octavio Paz
Panspermia today
Authors: Burchell M.J.
Published: December 2004

Panspermia is the idea that life migrates naturally through space. Although an old idea, there has been much recent theoretical and experimental work developing the idea in recent years. In this review, this progress is considered and placed in context. Ideas concerning Panspermia now include mathematical treatments of the likelihood of transfer of life from Mars to Earth, the possibility of life transferring between the natural satellites of an outer planet such as Jupiter, and mathematical treatments and models of life migrating out of a Solar System. Not all predictions of the likelihood of successful Panspermia are positive, and some are contradictory. At present, Panspermia can neither be proved nor disproved. Nevertheless, Panspermia is an intellectual idea which holds strong attraction. However, at the heart of Panspermia is a still un-resolved mystery: in order to migrate, life has to start somewhere, and we still cannot tackle that moment of origin.
A rating scale for wildness and ease of handling laboratory mice: results for 21 inbred strains tested in two laboratories
Authors: Wahlsten D. , Metten P. , Crabbe J. C.
Published: December 2004

Rating scales for difficulty in capturing and holding mice were devised that proved to be easy to use and highly sensitive to differences among mouse strains on the A and B priority lists of the Mouse Phenome Project. The simplicity of the scales makes it feasible to rate wildness during behavioral test sessions without adding much to testing time or distracting the technician from the principal task at hand. Overall wildness and placidity ratings obtained by combining capture and hold ratings provide a good impression of the difficulties encountered while working with lab mice in the course of complex experiments. Ratings of 21 inbred strains during the course of 15 behavioral tests in two laboratories demonstrated that the SPRET/Ei, PERA/Ei, CAST/Ei and SWR/J strains were particularly difficult to handle. The NOD/LtJ strain posed no special challenge in the Edmonton laboratory but was very difficult to handle in the Portland lab. The rating scales should be useful for judging the difficulties in working with novel targeted or induced mutations in mice as well as effects of a variety of environmental treatments or drugs.
Differential involvement of the Mu and Kappa opioid receptors in spatial learning
Authors: Jamot L. , Matthes H. W. D. , Simonin F. , Kieffer B. L. , Roder J. C.
Published: December 2004

In order to test the role of mu and kappa opioid receptors (Mu opioid receptor (MOR) and Kappa opioid receptor (KOR)) in hippocampal‐dependent spatial learning, we analyzed genetically engineered null mutant mice missing the functional MOR or KOR gene. Compared to wild‐type mice, the homozygous MOR null mutants exhibited an impairment in the ultimate level of spatial learning as shown in two distinct tasks, the 8‐arm radial‐maze and the Morris water‐maze. Control behaviors were normal. The learning impairment could be associated with the impairment we found in the maintenance of long‐term potentiation in mossy fibers in CA3. In comparison, there was no impairment in spatial learning in our KOR mutants or in mossy fibers (mf) in CA3 region long‐term potentiation (LTP). Our work suggests that the MOR may play a positive role in learning and memory by increasing LTP in CA3 neurons.
Interactive effects of drought and shade on three arid zone chenopod shrubs with contrasting distributions in relation to tree canopies
Authors: Prider J. N. , Facelli J. M.
Published: December 2004

Plants that grow beneath trees in arid systems may frequently experience both water and light limitation, although protection from high radiation loads during drought may compensate for a loss of productivity due to reduced light availability when water is plentiful.

We examined the effects of shading, during an imposed water deficit, on the carbon gain, stomatal conductance (gs) and shoot water potential (Ψs) of seedlings of three shrubs: Atriplex vesicaria (Heward ex Benth.), a C4 species, and Enchylaena tomentosa (R. Br.) and Rhagodia spinescens (R. Br.), which are restricted to shaded sites beneath trees.

Under conditions of limiting water, photosynthetic rates measured at saturating light (Amax) were negative in high‐light grown Enchylaena plants but remained positive in shade‐grown plants. When water was not limiting, Amax was reduced in shade‐grown Atriplex but shade did not affect carbon gain in the other two species.

AtriplexΨs was higher in shaded than in unshaded plants, but in unshaded plants positive carbon gain was maintained at Ψs below −10 MPa. Stomatal conductance and Amax decreased more slowly with increasing water deficit in shaded conditions in all species.

Atriplex was tolerant of a broader range of light and soil moisture conditions than Enchylaena, with Rhagodia intermediate between these two species. The interactive effect between drought and shade and the ecophysiological tolerances of these three species have consequences for their field distributions.
Confidence intervals on catch estimates from a recreational fishing survey: a comparison of bootstrap methods
Authors: Hoyle S. D. , Cameron D. S.
Published: December 2004

Bootstrap methods are often used for confidence intervals on recreational fish catch estimates, because they are relatively robust and straightforward to implement. Such data are typically highly skewed and zero‐inflated, presenting difficulties for many estimation methods. However, bootstrap performance in many situations is not well understood. Inaccurate confidence intervals can cause management errors, and biased intervals can promote errors in one direction. Although the analyses originate from recreational fisheries data, the conclusions are generally applicable to similarly distributed data from other sources. Using simulation, non‐parametric bootstrap confidence intervals (bootstrap normal, bootstrap percentile, hybrid, bootstrap‐t, BC, and BCa) on catch rate and total catch estimates from a recreational fishing survey were compared. The intervals' coverage (proportion of times the ‘true’ mean fell within the confidence intervals) and relative bias were also compared. The bootstrap‐t, using a resample size of slightly less than n/2, provided confidence intervals with the most correct coverage for both parameters. Intervals were biased, usually substantially, for all other methods, with the commonly used bootstrap percentile among the more biased methods.
Evaluation of large‐scale stocking of early stages of brown trout, Salmo trutta, to angler catches in the French–Swiss part of the River Doubs
Authors: Champigneulle A. , Cachera S.
Published: December 2004

Around 500 000 brown trout, Salmo trutta L., alevins are stocked annually in the 24‐km section of the River Doubs under study. All the alevins stocked in the period 1994–1996 were identifiable by fluoromarking their otoliths with tetracycline chlorhydrate. Anglers' catches, between June 1997 and September 1998, comprised trout aged 1+ to 7+ , but most (90% +) were 2+ to 3+ or 4+ , with the majority at 2+ and 3+. There was no significant difference in the size for a given age between marked and unmarked angled trout. The contribution of stocked fish in anglers' catches was around 22% for the 1995 cohort. The contribution of stocking (cohorts 1994 to 1995–1996) to the 1998 catches was around 23% (95% confidence limits: 19–27%). The estimated recapture rate was three to four trout per 1000 alevins stocked for the 1995 cohort. The major contribution (78%) of natural recruitment to anglers' catches suggests that the fishery management based on natural recruitment is still realistic in this part of River Doubs.
Reduction of a native fish fauna by alien species: an example from Brazilian freshwater tropical lakes
Authors: Latini A. O. , Petrere M.
Published: December 2004

The consequences of introducing Cichla cf. monoculus Spix & Agassiz, Astronotus ocellatus (Agassiz) and Pygocentrus nattereri Kner into lakes in the River Doce basin, Brazil, on richness, diversity and efficiency of aquatic macrophytes as natural refugia to native fishes was investigated. Samples were taken from lakes with and without alien fishes in areas with and without aquatic macrophytes. The presence of alien fishes reduced richness and diversity of the native fish community. The refugia function, which could be attributed to the clustering of aquatic macrophytes, does not exist in these lakes probably because the alien fishes exploit such habitats for reproduction. Since introductions threaten the native fish diversity of the region, studies on regional dispersion and factors that minimise the spread of alien fishes are needed.
Allozyme diversity in Australian rainbow trout, Oncorhynchus mykiss
Authors: Farrington L. W. , Austin C. M. , Burridge C. P. , Gooley G. J. , Ingram B. A. , Talbot B.
Published: December 2004

Rainbow trout, Oncorhynchus mykiss (Walbaum), were first introduced into Australia over 100 years ago, and forms the basis of important recreational inland fisheries and an aquaculture industry in south‐eastern Australia. This paper investigates the genetic variation within and between samples of Australian rainbow trout using allozyme electrophoresis. The levels of genetic diversity within Australia do not show marked differences from those observed in hatchery and wild populations from throughout North America, New Zealand and South Africa, but there is evidence for the loss of some rare alleles during translocation from California to Australia via New Zealand. No appreciable difference in genetic diversity was apparent between hatchery and self‐sustaining wild populations of rainbow trout from mainland Australia. However, significant differences in allelic frequencies were observed, with consistent genetic differences between Victorian and New South Wales samples most likely reflecting state‐based hatchery and stocking policies.
The influence of seasonal environmental changes on ontogenetic migrations of the squid Loligo gahi on the Falkland shelf
Authors: Arkhipkin A. I. , Grzebielec R. , Sirota A. M. , Remeslo A. V. , Polishchuk I. A. , Middleton D. A. J.
Published: December 2004

The Patagonian longfin squid Loligo gahi undertakes horizontal ontogenetic migrations on the Falkland shelf: juveniles move from spawning grounds located in shallow, inshore waters (20–50 m depths) to feeding grounds near the shelf edge (200–350 m depths). Immature squid feed and grow in these offshore feeding grounds and, upon maturation, migrate back to inshore waters to spawn. The possible influence of environmental factors on L. gahi migrations was investigated using data from oceanographic transects, crossing the region of known L. gahi occurrence. They were made from the inshore waters of East Falkland eastwards to depths of 1250 m on a monthly basis from 1999 to 2001. Four main water types were found in the region: Shelf, Sub‐Antarctic Superficial and Antarctic Intermediate water masses, and Transient Zone waters. The inshore spawning grounds occur in the Shelf Water mass, whereas the feeding squid (medium‐sized immature and maturing individuals) were associated with the Transient Zone. The 5.5°C isotherm appeared to mark the limit of squid distribution into deeper waters in all seasons. Seasonal changes in water mass characteristics and location were found to be important for seasonal changes in L. gahi migrations on the Falkland shelf.
Effect of temperature, age class, and growth on induction of aestivation in Japanese sandeel (Ammodytes personatus) in Ise Bay, central Japan
Authors: Tomiyama Minoru , Yanagibashi Shigeaki
Published: December 2004

We investigated the effects of temperature, age class, and growth on induction of aestivation in the Japanese sandeel (Ammodytes personatus) by means of rearing experiments and field surveys in Ise Bay, central Japan. Acoustic surveys and sampling of shoaling and aestivating sandeels indicated that the sandeels completed aestivation when the water temperature increased to 17–20°C. A rearing experiment showed that the mortality of sandeels reared without sand was greater than it was with sand, under replete feeding conditions. In a non‐aestivation rearing experiment without sand, the condition factor of the sandeels decreased when water temperatures exceeded 20°C, although they were fed to repletion. These results suggest that aestivation is induced by rising seawater temperature and plays an important role in energy conservation. The age‐1 group tended to start aestivation earlier than the age‐0 group in the field. Within the age‐0 group, larger sandeels tended to enter aestivation earlier. These observations indicate that fat reserves are an important cue to start aestivation.
Optimum temperature and food‐limited growth of larval Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) on Georges Bank
Authors: Buckley Lawrence J. , Caldarone Elaine M. , Lough R. Gregory
Published: December 2004

We estimated recent growth of Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) larvae collected on the southern flank of Georges Bank in May 1992–94 from the ratio of RNA to DNA (R/D) and water temperature. Growth of both species increased with water temperature to about 7°C and then decreased. The highest growth rates were observed in May 1993 at water temperatures around 7°C. These data confirm an earlier observation of comparable temperature optima for growth of Atlantic cod and haddock larvae in the north‐west Atlantic. Comparisons of field growth rates and temperature optima with data for larvae cultured at high temperatures and prey densities in the laboratory suggest that growth may have been food‐limited at higher temperatures on Georges Bank. Given that 7°C is the long‐term mean water temperature on the southern flank in May and that climate models predict a possible 2–4°C rise in water temperatures for the western North Atlantic, our findings point to a possible adverse effect of global warming on Atlantic cod and haddock.
Effects of essential fatty acids and N and P‐limited algae on the growth rate of tropical cladocerans
Authors: Ferrão‐Filho Aloysio S. , Fileto Cláudia , Lopes Norberto P. , Arcifa Marlene S.
Published: December 2004

SUMMARY 1. In this study, the effects of nutrient (N and P) deficiency and the importance of essential polyunsaturated fatty acids (PUFA) [eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] to tropical cladocerans, growth and reproduction were determined in a growth bioassay.

2. The animals were fed N/P‐sufficient, N‐deficient and P‐deficient algae, and also N and P‐deficient algae supplemented with fish oil emulsions rich in EPA and DHA.

3. Cladocerans showed different responses to nutrient‐deficient algae and also to supplements of fish oil emulsions. Moina micrura was most sensitive to P‐deficient alga and, surprisingly, grew better and produced more eggs in N‐deficient alga than in N/P sufficient alga. Ceriodaphnia cornuta was less sensitive, growing well in both N and P‐deficient algae. This species, however, had a lower clutch size in N‐deficient alga. On the other hand, Daphnia gessneri was the most sensitive to mineral limitation, showing decreased growth and clutch size in both nutrient‐deficient algae.

4. The PUFA supplements to nutrient‐deficient algae increased growth rates only for M. micrura and C. cornuta, suggesting that these fatty acids are important food requirements for these species.
Connectivity and cladoceran species richness in a metacommunity of shallow lakes
Authors: Cottenie Karl , De Meester Luc
Published: December 2004

SUMMARY 1. The shallow ponds of the nature reserve ‘De Maten’ form a metacommunity, in which individual ponds are highly interconnected via a system of overflows and rivulets. This study reports on the relations between cladoceran species richness and (a) connectivity patterns and (b) local environmental variables.

2. No relation was found between local species richness and three connectivity variables or dispersal pathways.

3. Spatial configuration was related to richness, but was confounded by environmental variables for 2 of 3 years. In those 2 years, there was a significant linear relation between Secchi disc depth and species richness, suggesting an important impact of the clearwater/turbid state alternative equilibria in shallow lakes in determining cladoceran richness. Only in the year in which environmental variables were unimportant did connectivity between the ponds influence species richness.

4. These results suggest that local environmental variables related to the clearwater/turbid state alternative equilibria in shallow lakes are important in determining cladoceran species richness. Connectivity and dispersal of individuals between the different ponds only act secondarily by increasing the general species richness within a pond through dispersal from ponds with different environmental conditions.
Occurrence of mixotrophic flagellates in relation to bacterioplankton production, light regime and availability of inorganic nutrients in unproductive lakes with differing humic contents
Authors: Bergström Ann‐Kristin , Jansson Mats , Drakare Stina , Blomqvist Peter
Published: December 2004

1. Field data from five unproductive Swedish lakes were used to investigate the occurrence of mixotrophic flagellates in relation to bacterioplankton, autotrophic phytoplankton, heterotrophic flagellates and abiotic environmental factors. Three different sources of data were used: (i) a 3‐year study (1995–97) of the humic Lake Örträsket, (ii) seasonal measurements from five lakes with widely varying dissolved organic carbon (DOC) concentrations, and (iii) whole lake enrichment experiments with inorganic nutrients and organic carbon.

2. Mixotrophic flagellates usually dominated over autotrophic phytoplankton in Lake Örträsket in early summer, when both bacterial production and light levels were high. Comparative data from the five lakes demonstrated that the ratio between the biomasses of mixotrophic flagellates and autotrophic phytoplankton (the M/A‐ratio) was positively correlated to bacterioplankton production, but not to the light regime. Whole lake carbon addition (white sugar) increased bacterial biomass, and production, reduced the biomass of autotrophs by a factor of 16, and increased the M/A‐ratio from 0.03 to 3.4. Collectively, the results indicate that the dominance of mixotrophs among phytoplankton was positively related to bacterioplankton production.

3. Whole lake fertilisation with nitrogen (N) and phosphorus (P) demonstrated that the obligate autotrophic phytoplankton was limited by N. N‐addition increased the biomass of the autotrophic phytoplankton but had no effect on mixotrophic flagellates or bacteria, and the M/A‐ratio decreased from 1.2 to 0.6 after N‐enrichment. Therefore, we suggest that bacteria under natural conditions, by utilising allochthonous DOC as an energy and carbon source, are able to outcompete autotrophs for available inorganic nutrients. Consequently, mixotrophic flagellates can become the dominant phytoplankters when phagotrophy permits them to use nutrients stored in bacterial biomass.

4. In Lake Örträsket, the biomass of mixotrophs was usually higher than the biomass of heterotrophs during the summer. This dominance could not be explained by higher grazing rates among the mixotrophs. Instead, ratios between mixotrophic and heterotrophic biomass (the M/H‐ratio) were positively related to light availability. Therefore, we suggest that photosynthesis can enable mixotrophic flagellates to outcompete heterotrophic flagellates.
Increase in photosynthetic efficiency as a strategy of planktonic organisms exploiting deep lake layers
Authors: Modenutti Beatriz , Balseiro Esteban , Callieri Cristiana , Queimaliños Claudia , Bertoni Roberto
Published: December 2004

1. The photosynthetic efficiencies of the mixotrophic ciliate Ophrydium naumanni and the autotrophic dinoflagellate Gymnodinium paradoxum were investigated using laboratory and field experiments in Lake Moreno Oeste (41°5′S and 71°33′W, 758 m a.s.l.), in the Nahuel Huapi System (North Patagonia, Argentina).

2. The effect of different underwater light intensities on net primary production (NPP) was assessed during one summer. Additionally, laboratory experiments were carried out to obtain photosynthesis‐irradiance response curves for each species.

3. Ophrydium naumanni and G. paradoxum dominated the metalimnetic (30 m depth) deep chlorophyll maximum (DCM) in the lake.

4. Despite these deep higher abundances, the cell‐specific production of both species was higher at 10 m than at 30 m (DCM) depth. In addition, at 5 m depth, NPP was reduced by PAR + UV‐A radiation.

5. Both species exhibited a positive NPP at very low irradiance but the mixotrophic ciliate was more efficient in exploiting the DCM irradiance level both in situ and at comparable light intensities in laboratory experiments. Light acclimatised O. naumanni showed a higher NPP at lower irradiances and photoinhibition at medium and high irradiances.

6. Under the strong wind‐driven turbulence commonly found in Patagonian lakes, organisms cannot select their position in the epilimnetic water column and will be dragged to potentially harmful UV radiation levels. Thus, metalimnetic DCM colonisation by these two species represents a tradeoff between higher survival and lower cell‐specific NPP.
Root anchorage of saplings and cuttings of woody pioneer species in a riparian environment
Authors: Karrenberg S. , Blaser S. , Kollmann J. , Speck T. , Edwards P. J.
Published: December 2004

The root anchorage ability of saplings and vegetative propagules may be decisive for persistence of woody pioneers in the highly disturbed habitat of floodplains.

Vertical uprooting resistance was investigated in saplings of three floodplain pioneers of central Europe, Alnus incana, Populus nigra and Salix elaeagnos, at the near‐natural River Tagliamento, north‐east Italy. Uprooting resistance of planted cuttings of P. nigra and S. elaeagnos was studied at this site and in an experimental garden.

Uprooting resistance was lowest in saplings of A. incana, intermediate in P. nigra, and highest in S. elaeagnos. For cuttings, differences in uprooting resistance between species were evident only under floodplain conditions, where resistance was higher in P. nigra than in S. elaeagnos. This difference was related to better growth in P. nigra.

The anchorage ability of saplings may be one factor influencing the longitudinal and transverse zonation of species in floodplains, as S. elaeagnos is restricted to highly disturbed sites close to the main channel, whereas A. incana and P. nigra occupy more stabilized habitats. For vegetative propagules, in contrast, regeneration ability may be more important than uprooting resistance.
Temperature and the chemical composition of poikilothermic organisms
Authors: Woods H. A. , Makino W. , Cotner J. B. , Hobbie S. E. , Harrison J. F. , Acharya K. , Elser J. J.
Published: December 2004

Temperature strongly affects virtually all biological rate processes, including many central to organismal fitness such as growth rate. A second factor related to growth rate is organismal chemical composition, especially C : N : P stoichiometry. This association arises because high rates of growth require disproportionate investment in N‐ and P‐rich biosynthetic cellular structures. Here the extent to which these factors interact is examined – does acclimation temperature systematically affect organismal chemical composition?

A literature survey indicates that cold‐acclimated poikilotherms contain on average 30–50% more nitrogen [N], phosphorus [P], protein and RNA than warm‐exposed conspecifics. The primary exception was bacteria, which showed increases in RNA content but no change in protein content at cold temperatures.

Two processes – changes in nutrient content (or concentration) and in organism size – contribute to the overall result. Although qualitatively distinct, both kinds of change lead to increased total catalytic capacity in cold‐exposed organisms.

Temperature‐driven shifts in nutrient content of organisms are likely to resonate in diverse ecological patterns and processes, including latitudinal and altitudinal patterns of nutrient content, foraging decisions by organisms living in strong temperature gradients, and patterns of biodiversity.
Tamo selectively modulates nuclear import in Drosophila
Authors: Minakhina Svetlana , Yang Jun , Steward Ruth
Published: December 2004

Background: The NF‐κB/Rel pathway functions in the establishment of dorsal‐ventral polarity and in the innate humoral and cellular immune response in Drosophila. An important aspect of all NF‐κB/Rel pathways is the translocation of the Rel proteins from the cytoplasm to the nucleus, where they function as transcription factors.

Results: We have identified a new protein, Tamo, which binds to Drosophila Rel protein Dorsal, but not to Dorsal lacking the nuclear localization sequence. Tamo does not bind to the other Drosophila Rel proteins, Dif and Relish. The Tamo‐Dorsal complex forms in the cytoplasm and Tamo also interacts with a cytoplasmically orientated nucleoporin. In addition Tamo binds the Ras family small GTPase, Ran. Tamo functions during oogenesis and, based on phenotypic analysis, controls the levels of nuclear Dorsal in early embryos. It further regulates the accumulation of Dorsal in the nucleus after immune challenge.

Conclusions: Tamo has an essential function during oogenesis. Tamo interacts with Dorsal and proteins that are part of the nuclear import machinery. We propose that tamo modulates the levels of import of Dorsal and other proteins.
Alleles of the proximal promoter of BAT1, a putative anti‐inflammatory gene adjacent to the TNF cluster, reduce transcription on a disease‐associated MHC haplotype
Authors: Wong Agnes M.‐L. , Allcock Richard J. N. , Cheong Karey Y. M. , Christiansen Frank T. , Price Patricia
Published: December 2004

Background: BAT1 belongs to the DEAD‐box family of proteins, and is encoded in the central region of the MHC, a region containing genes affecting immunopathological disorders including Type 1 diabetes. We showed that BAT1 can reduce inflammatory cytokine production, supporting its candidacy as a disease gene. Here we examined the proximal promoter region of BAT1.

Results: Ten single nucleotide polymorphisms were identified in ≈1.4 kb of sequence, defining at least seven alleles. Sections of the BAT1 promoter region were amplified from cells homozygous for the MHC haplotypes associated with susceptibility (HLA‐A1, B8, DR3; 8.1 haplotype) and resistance (HLA‐A3, B7, DR15; 7.1 haplotype) to diabetes and cloned into a promoter‐less luciferase‐encoding plasmid. Jurkat cells transiently transfected with fragments from the 8.1 haplotype exhibited a lower luciferase activity than those transfected with fragments from the 7.1 haplotype, indicating reduced transcription. The effect was clearest with the 520 bp immediately upstream of the transcriptional start site. Electrophoretic mobility shift assays using oligonucleotides spanning polymorphic sites within the 520 bp (proximal) promoter fragment showed haplotype‐specific binding of nuclear proteins.

Conclusions: In view of the anti‐inflammatory role of BAT1, reduced production on a disease‐associated haplotype constitutes a novel and self‐consistent model for the effect of central MHC genes on disease.
A SWI2/SNF2‐type ATPase/helicase protein, mDomino, interacts with myeloid zinc finger protein 2A (MZF‐2A) to regulate its transcriptional activity
Authors: Ogawa Hironori , Ueda Takeshi , Aoyama Tomohisa , Aronheim Ami , Nagata Shigekazu , Fukunaga Rikiro
Published: December 2004

Background: The myeloid zinc finger protein 2A (MZF‐2A) is a Krüppel‐type C2H2 zinc finger transcription factor expressed in myeloid cells and involved in the growth, differentiation and tumorigenesis of myeloid progenitors. Previously we identified a 180 amino acid domain in MZF‐2A which is responsible for the transcriptional activation of MZF‐2A. To understand the mechanism of the MZF‐2A‐dependent transcriptional activation, we screened for molecules that interact with the transactivation domain (TAD) of MZF‐2A.

Results: By using the yeast Ras recruitment two‐hybrid screening, we identified a novel SWI2/SNF2‐related protein, termed mammalian Domino (mDomino), as an MZF‐2A‐binding partner. The mDomino protein, which shows a marked similarity to the Drosophila Domino protein, contains a SWI2/SNF2‐type ATPase/helicase domain, a SANT domain, and a glutamine‐rich (Q‐rich) domain. The C‐terminal Q‐rich domain of mDomino physically associates with the TAD of MZF‐2A in mammalian cells as well as in yeast. Expression of the mDomino Q‐rich domain, together with MZF‐2A in myeloid LGM‐1 cells, enhanced the MZF‐2A‐mediated activation of a reporter gene.

Conclusions: These results strongly suggest that an ATP‐dependent chromatin‐remodelling complex containing mDomino interacts with MZF‐2A to regulate gene expression in myeloid cells.
A brute force postgenome approach to identify temperature‐sensitive mutations that negatively interact with separase and securin plasmids
Authors: Matsumura Takuhiro , Yuasa Tatsuro , Hayashi Takeshi , Obara Takayuki , Kimata Yuu , Yanagida Mitsuhiro
Published: December 2004

Background: The fission yeast Schizosaccharomyces pombe separase/Cut1 and securin/Cut2 are required for anaphase‐specific activation of proteolysis that leads to proper sister chromatid separation. We intended to identify ts (temperature sensitive) strains whose growth was inhibited by multicopy plasmid pCUT1 or pCUT2 at the permissive temperature.

Results: After a one‐by‐one transformation of 1015 randomly isolated ts strains, 18 transformants that retarded in colony formation at the permissive or semipermissive temperature were isolated. Six of them, in the absence of pCUT1 or pCUT2, produced mitotic phenotypes with condensed chromosomes at the restrictive temperature. Gene cloning established that these mutants were defective in either the subunits (Cut9, Cut23, Cut20 or Apc10) of APC (anaphase promoting complex)/cyclosome or Cut8, a regulator for 26S proteasome localization. The inhibitory effect of separase against APC/cyclosome mutations was abolished when the catalytic site mutation C1730A was introduced and overproduced, indicating that inhibition needs an active separase. Securin/Cut2 overproduction also caused a negative effect on these mutants. Surprisingly, the phenotypes of cut9 and cut23 in the presence of pCUT1 or pCUT2 were not the mitotic arrest, and they were strikingly different depending on pCUT1 or pCUT2.

Conclusions: This study shows the functional link between separase/Cut1 and APC/cyclosome in a separase activity‐dependent manner. The negative effect of active separase overproduction on APC/cyclosome mutations is possibly due to the direct inhibition of APC/cyclosome. In addition, the manner of the inhibition by high copy securin and separase plasmids were quite different each other and did not result in the mitotic block.