bluuebunny/crossref_metadata_2025 huggingface dataset:
Revised stratigraphical nomenclature for the Permo-Triassic Flagstone Bench Formation, northern Prince Charles Mountains, East Antarctica
Authors: Webb J. A. , Fielding C. R.
Published: December 2007

The East Antarctic Craton contains only one substantial outcrop of Palaeozoic–Mesozoic strata between 0° and 150°E; this lies in Mac. Robertson Land, on the eastern margin of the northern Prince Charles Mountains. These rocks are known as the Amery Group (Mond 1972, McKelvey & Stephenson 1990) and comprise dominantly fluviatile sandstones, with subordinate shales, coals and conglomerates. The lower formations of the Amery Group, the Radok Conglomerate and Bainmedart Coal Measures, contain a diverse Stage 5 palynomorph assemblage indicating a Baigendzhinian–Tatarian age (late Early–Late Permian, hereafter abbreviated as mid–Late Permian; Dibner 1978).
Survival of faecal bacteria in Antarctic coastal waters
Authors: Statham Jo A. , McMeekin Tom A.
Published: December 2007

The effect of solar radiation on the survival of Escherichia coli, Salmonella zanzibar and a faecal Streptococcus strain in seawater was tested in laboratory experiments, and survival of E. coli was tested under natural light conditions at Davis Station, Antarctica. Exposure to artificial light of wavelengths 290–800 nm caused a rapid decline in viability of each strain examined. T90 values (the time taken for 90% of the population to be inactivated) were ~50 min, 40 min and 2 h for E. coli, S. zanzibar and the faecal Streptococcus respectively. Selective removal of UV-B wavelengths of (<320 nm) increased survival of E. coli and S. zanzibar, resulting in T90 values of ~2.5 h. Screening out wavelengths of <370 nm (UV-B and most of UV-A) increased T90 values to 5 h for E. coli and 10 h for S. zanzibar. The visible band of the spectrum (400–800 nm) also had deterimental effects on faecal bacteria, when compared with survival in the absence of light. Rates of decline for E. coli in natural light in Antarctica were similar to those from laboratory experiments. However, resuscitation of sub-lethally damaged cells under optimum conditions resulted in greater recovery rates than were observed after exposure to artificial sunlight. Faecal bacteria were rapidly inactivated when exposed to sunlight in Antarctic waters, and as repair mechanisms are unlikely to operate under in situ conditions, resuscitation of sub-lethally damaged cells is improbable.
Length and age at maturity of Antarctic krill
Authors: Siegel V. , Loeb V.
Published: December 2007

Data from several summer research cruises in the Antarctic Peninsula region were analysed to calculate length (L50) and age at maturity for the Antarctic krill, Euphausia superba. Length at maturity L50 is defined as the length at which 50% of the krill stock attains sexual maturity. L50 values of 34.65–35.91 mm for female krill are the best estimates for the peak spawning season. Males attain sexual maturity later at L50 values of 43.35–43.71 mm. Length at maturity and length at first spawning are identical for krill. Comparisons with mean length-at-age data show that females mature in the third growth season (age class 2+), while males reach maturity in the fourth year (age class 3+). Both sexes show ‘knife-edge maturity’.
Isomer-specific analysis and toxic potential evaluation of polychlorinated biphenyls in Antarctic fish, seabirds and Weddell seals from Terra Nova Bay (Ross Sea)
Authors: Focardi S. , Bargagli R. , Corsolini S.
Published: December 2007

To provide data on the degree of contamination of the marine ecosystem isomer-specific concentrations of polychlorinated biphenyls, including planar, mono- and di-ortho congeners, were measured in the Weddell seal, the Adélie penguin, the south polar skua, and in two species of Antarctic fish (Trematomus bernacchii and Chionodraco hamatus) from Terra Nova Bay, Antarctica. The results show a clear relation between PCB concentrations and trophic level, in the order fish < Adélie penguin < Weddell seal. The higher values found in the skua appear to be related to its migration to more contaminated lower latitudes. The data for the various PCB congeners were used to calculate toxic potential in the different animals. The 2,3,7,8-TCDD toxic equivalents of coplanar congeners were estimated by the “toxic equivalent factors” (TEFs) approach. The highest values of TEFs were found in the south polar skua and Weddell seal. Values in the other species were considerably lower.
The diet of the Antarctic fish Trematomus newnesi Boulenger, 1902 (Nototheniidae) from Terra Nova Bay, Ross Sea
Authors: Vacchi M. , La Mesa M.
Published: December 2007

A coastal ichthyological survey was carried out in Terra Nova Bay, Ross Sea during the Italian Antarctic Expedition 1987/1988. Vacchi et al. (1992) described the composition of the coastal fish community. Stomach content analysis was conducted on Trematomus bernacchii and T. pennellii to evaluate the trophic overlap (Vacchi et al. 1994). During the survey, several specimens of T. newnesi were caught at 92 m depth. This fish is a coastal species widespread in the high-Antarctic Zone and also known from the South Shetland Islands and the South Orkney Islands (DeWitt et al. 1990). Although T. newnesi was found down to 400 m depth (Tiedtke & Kock 1989), it seems more abundant in very shallow inshore waters (Naito & Iwami 1982, Williams 1988). Andriashev (1970) and Williams(1988) stated T. newnesi was a cryopelagic species associated with the underside of the sea-ice. At Signy Island, T. newnesi was described as semipelagic species eating amphipods (Richardson 1975). Eastman & DeVries (1982) consider it to be both a cryopelagic and benthic species in McMurdo Sound. Targett (1981) found that T. newnesi feeds on krill and plankton at the South Orkney Islands. Planktivory has also been indicated at the South Shetland Islands (Casaux et al. 1990).
Biostratigraphy and palaeoecology of early Pliocene diatom assemblages from the Larsemann Hills, eastern Antarctica
Authors: McMinn A. , Harwood D.
Published: December 2007

Considerable controversy surrounds the biostratigraphic and palaeoclimatic interpretation of Antarctic marine Pliocene sequences (Webb & Harwood 1991). The object of this note is to document and reassess a marine Pliocene diatom assemblage from the Larsemann Hills and to discuss its significance with respect to other Antarctic Neogene deposits.
Reassessment of the first lichen and moss collections from Heimefrontfjella, Dronning Maud Land
Authors: Thor Göran
Published: December 2007

The lichen and moss collections by G.T. Bowra in Heimefrontfjella in 1963–64 are redetermined. These are the only plant collections made in Heimefrontfjella prior to a Swedish expedition in 1991–92. Taxonomical and nomenclatural improvements have resulted in several changes. A total of 16 lichens and two mosses were found.
Current status of Odontocetes in the Antarctic
Authors: Kasamatsu Fujio , Joyce Gerald G.
Published: December 2007

The current status of Antarctic Odontocetes – sperm whales Physeter catodon, killer whales Orcinus orca, long-finned pilot whales Globicephala melaena, hourglass dolphins Lagenorhynchus cruciger and poorly known species of beaked whales (family Ziphiidae)–were studied in Anatarctic waters using data gathered in sighting surveys conducted from 1976/77 to 1987/88. Temporal variation in density demonstrated the different migration patterns by species, especially between sperm whale and killer whale. Spatial distributions during mid-summer demonstrated different peaks of occurrence for each species by latitude that suggest possible segregation between the species. Killer whales occur mainly in the very southernmost areas, sperm whales in the southern half of the study area, beaked whales (mostly southern bottlenose whales Hyperoodon planifrons) ranged over a wide area, and long-finned pilot whales and hourglass dolphins were mainly in the northern regions of Antarctic waters. Several longitudinal peaks of occurrence and apparent distribution gaps were identified for sperm, beaked and killer whales. Abundance estimates for south of the Antarctic Convergence in January are based on line transect theory and were 28 100 animals (coefficient of variation CV 0.18) sperm whales, 599 300 (0.15) beaked whales (mostly southern bottlenose whales), 80 400 (0.15) killer whales, 200 000 (0.35) long-finned pilot whales, and 144 300 (0.17) hourglass dolphins. Based on this, biomass of these species were estimated as 0.77 (sperm whales), 2.70 (beaked whales), 0.32 (killer whales), 0.16 (long-finned pilot whales) and 0.01 (hourglass dolphins) million tonnes. Consumption of food (mostly squid) by the Odontocetes is estimated as 14.4 million tonnes with 67% of the total consumed by beaked whales. Indirect consumption of Antarctic krill through the predation of squid by beaked whales is estimated to be c. 24 million tonnes. This value is similar to the estimate of krill consumption by penguins in the Antarctic (33 million tonnes). Odontocetes, especially southern bottlenose whales, are suggested to have a much greater role in the Antarctic ecosystem than has previously been considered.
The compound eye as an indicator of age and shrinkage in Antarctic krill
Authors: Sun S. , Mare William De La , Nicol Stephen
Published: December 2007

Laboratory studies have shown that Antarctic krill (Euphausia superba) shrink if maintained in conditions of low food availability. Recent studies have also demonstrated that E. superba individuals may be shrinking in the field during winter. If krill shrink during the winter, conclusions reached by length-frequency analysis may be unreliable because smaller animals may not necessarily be younger animals. In this study, the correlation between the body-length and the crystalline cone number of the compound eye was examined. Samples collected in the late summer show an apparent linear relationship between crystalline cone number and body-length. From a laboratory population, it appears that when krill shrink the crystalline cone number remains relatively unchanged. If crystalline cone number is little affected by shrinking, then the crystalline cone number may be a more reliable indicator of age than body-length alone. The ratio of crystalline cone number to body-length offers a method for detecting the effect of shrinking in natural populations of krill. On the basis of the crystalline cone number count, it appears from a field collection in early spring that E. superba do shrink during winter.
Consumption of marine resources by seabirds and seals in Crozet and Kerguelen waters: changes in relation to consumer biomass 1962–85
Authors: Guinet C. , Cherel Y. , Ridoux V. , Jouventin P.
Published: December 2007

The total annual food consumption of the seabird and seal community breeding at lles Kerguelen was estimated to be 1.8×106 t in 1985. This biomass included c. 0.99×106 t (55%) of crustaceans, 0.46×106 t (26%) of myctophid fish, 0.07×106 t (4%) of other fish species, and 0.26×106 t (15%) of squid. During the same year, the mass of prey consumed in Crozet waters was previouly estimated to be 3.1×106 t, the total food consumption in the Indian Ocean area including the two archipelagos thus totalling c. 5×106 t in 1985. Four species of top predators, the king penguin, macaroni penguin, elephant seal, and fur seal, consumed 59% and 56% of the amount of prey eaten in 1985 by the whole community at Kerguelen and Crozet islands, respectively. Between 1962 and 1985, population changes of these four species induced 18 and 41% increases in their food consumption at Kerguelen and Crozet islands. Population changes included a moderate increase in the number of macaroni penguins and a marked rise of king penguin populations. Assuming that the diet of king penguin was similar in 1962 and 1985, its population increase will have required a concomitant increase of 0.6×106 t in the consumption of myctophid fish in Crozet and Kerguelen waters.
Global change for ever!
Authors: Thomson Michael
Published: December 2007

How is your global change credibility? Does your research fit nicely into unravelling what has happened over the last few thousand years, what is happening now, what might happen in the next few years. If so, well done! Your research is probably well reviewed and well funded.
Mesozooplankton biomass distribution in the upper 100 m layer of the Atlantic sector of the Southern Ocean
Authors: Rudjakov Jury A.
Published: December 2007

The distribution of annual mean biomass of mesozooplankton (animals in the size range 0.2–20 mm) in the upper layer (0–100 m) of the Atlantic sector of the Southern Ocean was mapped. The map was constructed from 4216 measurements at 2184 oceanographic stations, from the Russian and Brazilian archive records, from published sources, and from the British Oceanographic Data Centre. The annual mean mesozooplankton biomass value for the South Atlantic is estimated in this study to be 93 mg m−3 wet weight.
Antarctic mapping: a bleak future?
Authors: Thomson Janet
Published: December 2007

Antarctic cartographers face many challenges. They are required to prepare accurate maps of a remote and dangerous environment in support of science programmes, logistic operations, and search and rescue activities. Yet they have limited resources in terms of manpower, funds and primary source material for this vital work, perhaps because their science discipline is held in low esteem by their peers. They are commonly regarded as service providers rather than scientists in their own right.
Freshwater diatoms from some islands in the maritime Antarctic region
Authors: Vijver Bart Van De , Beyens Louis
Published: December 2007

A total of 69 diatom taxa, belonging to 24 genera were recorded from thirteen freshwater and moss samples collected in the Antarctic Peninsula region. Marine taxa comprised 26%. Cluster analysis revealed three assemblages. The Nitzschia acidoclinata assemblage occurs on wet mosses; the Luticola muticopsis assemblage is found near penguin rookeries whereas the Pinnularia krookii–Pinnularia microstauron var. elongata assemblage occurs on drier places such as dry mosses and drying mud.
Seasonal occurrence and diet of leopard seals (Hydrurga leptonyx) at Bird Island, South Georgia
Authors: Walker T. R. , Boyd I. L. , McCafferty D. J. , Huin N. , Taylor R. I. , Reid K.
Published: December 2007

Seasonal haul-out patterns and diet of individually marked leopard seals (Hydrurga leptonyx) were investigated at Bird Island, South Georgia during the 1983–96 winters. A total of 2956 leopard seal sightings were made, and 121 seals were tagged during the study, mainly between 1993 and 1996. Photographs of scars and pelage patterns were also used to identify a subset of these individuals across years, which provided no evidence of tag loss between or within years. Leopard seals were observed between April and November; the mean time between the first and last sightings in each year was 208 d (s d ± 48). Between 1993–96, eight seals were resident around the island for more than 100 d, and the longest recorded residence was 130 d. The proportion of tagged seals resighted was 0.35 and 0.17 in 1995 and 1996 respectively. Based on estimates of body length, <5% of the seals were juveniles (0–1 years) and >70% were not sexually mature. There was considerable inter-annual variation in abundance, with a maximum of 502 sightings during 1994, compared with a minimum of 21 during 1986 and 1989. Antarctic fur seals (Arctocephalus gazella) were the main prey item (58% of kills observed and 53% of scats). Other items included penguins (28% of kills observed and 20% of scats) and fish (24% of scats). Antarctic krill (Euphausia superba), southern elephant seals (Mirounga leonina) and seabirds other than penguins were also present in the diet in small quantities.
Characteristics of the boundary layer thermal structure at a coastal region of Adélie Land, East Antarctica
Authors: Gera B. S. , Argentini S. , Mastrantonio G. , Viola A. , Weill A.
Published: December 2007

The boundary layer thermal structure, observed through Doppler sodar, at Dumont d'Urville, has been analysed. Typical echograms of the spiky layers, wavy layers and thermal plumes, except for the eroding inversion, have been observed. The annual distribution of these thermal structures is presented. The spiky layers are observed to coincide with strong winds (mainly katabatic) flowing from the inner continent sector, 90°–180°. The upper boundary of the spiky layers is correlated to the wind direction; the maximum depths (more than 400 m) are confined to 60° wide span centred at 135°. The predominant waves and the spiky layers, tend to occur alternately in accordance with the relative dominance of the katabatic flow intensity and the stability conditions. The sodar signatures of these structures are examined in relation to the onset and dissipation time, duration and the seasonal distribution. Both waves and spiky layers occur at any hour of the day; their maximum occurrence is in winter months. The persistence of the waves varies from a couple of hours to a couple of days while the spiky layers can occur for periods even longer than 3–4 days. The characteristics of these phenomena are associated with the diurnal radiational cycle and the temperature contrast in proximity to the coast.
Population dynamics of the bivalve Laternula elliptica from Potter Cove, King George Island, South Shetland Islands
Authors: Urban H.-Jörg , Mercuri Guillermo
Published: December 2007

Body size, geographical distribution and biomass make Laternula elliptica one of the most important bivalve species of the Antarctic. A complete study on the population dynamics (reproduction cycle, growth, mortality and productivity) of this species from King George Island gave growth parameters for the von-Bertalanffy-growth-function of: L∞ = 112.2 mm, K = 0.160 yr 1, t0 = 0.000 yr. Total mortality was estimated as Z = 0.392 yr−1. Somatic production and mean biomass of two distinct sub-populations were 8.7 and 67.3 g AFDW m−2 yr−1 at Beach & Glacier and 20.0 and 88.6 g AFDW m−2 yr−1 at Punta Elefante. The following P / B values were calculated; Beach & Glacier = 0.129, Punta Elefante = 0.226. It is suggested that these differences are linked to mortality caused by icebergs which is expected to be higher at the shallower Punta Elefante site.
Recent population change of the southern elephant seal at Îles Crozet and Îles Kerguelen: the end of the decrease?
Authors: Guinet Christophe , Jouventin Pierre , Weimerskirch Henri
Published: December 2007

The elephant seal populations breeding on the Îles Crozet and Kerguelen were regularly surveyed over the last three decades. At Îles Kerguelen the number of breeding females decreased at an annual rate of 3.6% between 1970 and 1987, then increased at an annual rate of 1.1% to 1997. At Îles Crozet, the population was reported to decrease at a rate of 5.35% between 1970 and 1990 but no change in numbers was found between 1990 and 1997. These results indicate that the rapid decline observed both at Îles Crozet and Îles Kerguelen has ended, and these populations are now either stable or slightly increasing. We suggest that broad scale change in environmental factors affecting the food availability for elephant seals may be responsible for the change in numbers of these marine predators. The higher rate of decrease, the longer period of decline, and the absence of any significant change between 1990 and 1997 observed on the Îles Crozet may be explained by additional factors such as killer whale predation.
Recent progress in magnetic anomaly mapping over Victoria Land (Antarctica) and the GITARA 5 survey
Authors: Bozzo E. , Ferraccioli F. , Gambetta M. , Caneva G. , Spano M. , Chiappini M. , Damaske D.
Published: December 2007

Magnetic anomaly mapping is used to interpret crustal structure and tectonic evolution of Victoria Land and of the adjacent Ross Sea. Previous interpretation of magnetic anomalies verified seismic and gravimetric findings in the Ross Sea by placing additional constraints both on crustal structure and magmatism of the West Antarctic rift system. An aeromagnetic map of the central-southern part of Victoria Land produced in the framework of the GITARA project, provides new crustal images of part of the Transantarctic Mountains rift shoulder. The map was interpreted to study the transition between the Wilson Terrane and the Precambrian East Antarctic Craton, the extent and distribution of Jurassic tholeiitic magmatism, and the occurrence of post- Jurassic faulting oblique to the rift basins. A compilation with adjacent aeromagnetic data was recently used to study the structures inherited from the Palaeozoic terranes and their reactivation as major fault zones separating different crustal blocks along the TAM rift shoulder. Additional aeromagnetic coverage over a 35 500 km2 sector of northern Victoria Land was acquired during the GITARA 5 (1996/97) survey. The flight altitude was 9000 ft and profile line spacing was 4.4 km for the regional grid and 2.2 km for the detailed one, with a tie line interval of 22 km. Standard processing techniques, optimized with microlevelling procedures were applied to the data to produce a 1:250 000 magnetic anomaly map. The processed GITARA 5 magnetic dataset is a new tool to study the structure of the Rennick Graben, and its relationship to the Palaeozoic Wilson Terrane-Bowers Terrane and Robertson Bay Terrane suture zone. The new map also represents important progress towards a magnetic anomaly compilation over the whole of Victoria Land, since it links previous efforts near the Pacific Coast with those near the Ross Sea.
Significance of selected halocarbons monitoring in air samples collected in the Terra Nova Bay region (northern Victoria Land, Antarctica)
Authors: Mangani Filippo , Maione Michela , Lattanzi Luciano
Published: December 2007

CCl3F (or CFC-11) and CCl2F2 (or CFC-12) were determined in air samples collected, during subsequent summer Antarctic campaigns, in different sampling sites in the Ross Sea Region. The samples were analysed by GC-ECD after enrichment. Data obtained since 1988–89 were plotted to observe the trend of CFCs atmospheric concentration levels. A decrease in the rate of increase of CFC-12 concentration was observed, whilst the concentration of CFC-11 was actually seen to be decreasing.
Rediscovery of the Antarctic species Sipho gaini Lamy, 1910 (Gastropoda: Neogastropoda) with remarks on its taxonomic position
Authors: Kantor Yuri I. , Harasewych M.G.
Published: December 2007

Examination of the holotype of Sipho gaini Lamy, 1910, attributed by recent authors to the genus Chlanidota (Buccinulidae), revealed that this species belongs to the genus Belaturricula and is a senior synonym of Belaturricula antarctica Dell, 1990. A redescription of the shell, anterior alimentary system, and radular morphology of Belaturricula gaini is provided. The genus Belaturricula is transferred to the family Conidae (sensu Taylor et al. 1993) on the basis of its radula, which is composed of hollow marginal teeth. The presence of a large shell, prominent operculum, acinous salivary glands, radular teeth with narrow bases in B. gaini, as well as the absence of buccal lips and rhyncodeal introvert, all indicate affinities with the conid subfamily Clathurellinae. Because the radula of Pontiothauma ergata Hedley (1916) is nearly indistinguishable from that of Belaturricula gaini, we reassign Hedley's species to the genus Belaturricula as Belaturricula ergata (Hedley, 1916).
Phase equilibria in model surfactants forming Langmuir monolayers
Authors: Ramírez E. , Santana A. , Cruz A. , López G. E.
Published: December 2007

The study of Langmuir monolayers has generated the attention of researchers because of their unique properties and their not well understood phase equilibrium. These monolayers exhibit interesting phase diagrams where the unusual liquid-liquid equilibrium can be observed for a single component monolayer. Monte Carlo computer simulations in the virtual Gibbs ensemble were used to obtain the phase diagram of Langmuir monolayers. The liquid-vapor and liquid-liquid phase equilibria were considered by constructing the Cailletet-Mathias phase diagrams. By using the Ising model and the rectilinear approximations the identification of the critical properties for both equilibria was determined. These critical parameters were calculated as a function of the strength of the interaction between the surfactant molecules and the aqueous subphase. As a result, we have identified the coexistence between a liquid expanded state (LES)-vapor and the liquid condensed state-LES, in agreement with experimental and theoretical evidence in the literature. We obtained a clear separation of phases and a strong dependence on the strength of the solvent used. Namely, as the interaction between the solvent and the head of the surfactant increases, the critical properties also increase. Equilibrium states were characterized by computing thermodynamic quantities as a function of temperature and solvent strength.
Room temperature magnetocaloric effect in Ni–Mn–In
Authors: Bhobe P. A. , Priolkar K. R. , Nigam A. K.
Published: December 2007

We have studied the effect of magnetic field on a nonstoichiometric Heusler alloy Ni50Mn35In15 that undergoes a martensitic as well as a magnetic transition near room temperature. Temperature dependent magnetization measurements demonstrate the influence of magnetic field on the structural phase transition temperature. From the study of magnetization as a function of applied field, we show the occurrence of inverse-magnetocaloric effect associated with this magneto-structural transition. The magnetic entropy change attains a value as high as 25J∕kgK (at 5T field) at room temperature as the alloy transforms from the austenitic to martensitic phase with a concomitant magnetic ordering.
Biogenic formation of photoactive arsenic-sulfide nanotubes by
Shewanella
sp. strain HN-41
Authors: Lee Ji-Hoon , Kim Min-Gyu , Yoo Bongyoung , Myung Nosang V. , Maeng Jongsun , Lee Takhee , Dohnalkova Alice C. , Fredrickson James K. , Sadowsky Michael J. , Hur Hor-Gil
Published: December 2007

Microorganisms facilitate the formation of a wide range of minerals that have unique physical and chemical properties as well as morphologies that are not produced by abiotic processes. Here, we report the production of an extensive extracellular network of filamentous, arsenic-sulfide (As-S) nanotubes (20–100 nm in diameter by ≈30 μm in length) by the dissimilatory metal-reducing bacterium
Shewanella
sp. HN-41. The As-S nanotubes, formed via the reduction of As(V) and S
2
O
3
2−
, were initially amorphous As
2
S
3
but evolved with increasing incubation time toward polycrystalline phases of the chalcogenide minerals realgar (AsS) and duranusite (As
4
S). Upon maturation, the As-S nanotubes behaved as metals and semiconductors in terms of their electrical and photoconductive properties, respectively. The As-S nanotubes produced by
Shewanella
may provide useful materials for novel nano- and opto-electronic devices.
Reciprocity between phase shifts and amplitude changes in the mammalian circadian clock
Authors: Pulivarthy Sandhya R. , Tanaka Nobushige , Welsh David K. , De Haro Luciano , Verma Inder M. , Panda Satchidananda
Published: December 2007

Circadian rhythms help organisms adapt to predictable daily changes in their environment. Light resets the phase of the underlying oscillator to maintain the organism in sync with its surroundings. Light also affects the amplitude of overt rhythms. At a critical phase during the night, when phase shifts are maximal, light can reduce rhythm amplitude to nearly zero, whereas in the subjective day, when phase shifts are minimal, it can boost amplitude substantially. To explore the cellular basis for this reciprocal relationship between phase shift and amplitude change, we generated a photoentrainable, cell-based system in mammalian fibroblasts that shares several key features of suprachiasmatic nucleus light entrainment. Upon light stimulation, these cells exhibit calcium/cyclic AMP responsive element-binding (CREB) protein phosphorylation, leading to temporally gated acute induction of the
Per2
gene, followed by phase-dependent changes in phase and/or amplitude of the PER2 circadian rhythm. At phases near the PER2 peak, photic stimulation causes little phase shift but enhanced rhythm amplitude. At phases near the PER2 nadir, on the other hand, the same stimuli cause large phase shifts but dampen rhythm amplitude. Real-time monitoring of PER2 oscillations in single cells reveals that changes in both synchrony and amplitude of individual oscillators underlie these phenomena.
A Breach in the Wall
Authors: Yetaai
Published: December 2007

The Chinese citizen Yetaai is suing China Telecom for blocking his website. It is an unprecedented case which, if successful, would force an admission that censorship — the Great Firewall — exists. This is an extract from his blog.
In Vitro Testing of Cyto- and Genotoxicity of New Porphyrin Water-Soluble Metal Derivatives
Authors: Gasparyan Gennadi , Hovhannisyan Galina , Ghazaryan Robert , Sahakyan Lida , Tovmasyan Artak , Grigoryan Rusanna , Sarkissyan Natalia , Haroutiunian Samvel , Aroutiounian Rouben
Published: December 2007

Porphyrins and porphyrin derivatives have an outstanding potential for discovery of novel pharmacological agents due to their ability for numerous chemical modifications and a variety of mechanisms of biological effects. New water-soluble Ag and Zn derivatives of tetrachloride meso-tetra (4- N-oxiethylpyridyl) porphyne were synthesized. Cyto- and genotoxicity of these substances were tested in vitro by the vital dye (trypan blue) exclusion and the micronucleus tests, respectively. Both metalloporphyrins were shown to be cytotoxic for Cos-7 (fibroblast-like African green monkey kidney cells transformed by simian virus 40 [SV40]), DU 145 (epithelial-like cells of human prostate carcinoma), and K-562 (human chronic myeloid leukemia cells) cell lines. At the same time they did not cause chromosome fragmentation in K-562 cell line at as high concentrations as IC50 (20 μmol/L for Ag and 70 μmol/L for Zn derivative). Thus, the metalloporphyrins tested meet at least two important demands to potential anticancer drugs as they combine the cytotoxicity with low genotoxicity. The three in vitro tumor models used are relevant to further in vitro and in vivo pre-clinical investigation of the studied metalloporphyrins as potential chemotherapeutics.
Combined Effects of Vitamin C, Vitamin E, and Sodium Selenate Supplementation on Absolute Ethanol-Induced Injury in Various Organs of Rats
Authors: Yanardag Refiye , Ozsoy-Sacan Ozlem , Ozdil Sadakat , Bolkent Sehnaz
Published: December 2007

In this study, the effect of combination of vitamin C (ascorbic acid), vitamin E ( α-tocopherol), and selenium (sodium selenate) on ethanol-induced liver and intestine injury in rats was investigated. The ethanol-induced injury was produced by the administration of 1 ml of absolute ethanol to each rats. Animals received vitamin C (250 mg/kg), vitamin E (250 mg/kg), and sodium selenate (Se) (0.5 mg/kg) for 3 days; 1 h after the final antioxidant administration, they were sacrificed. Lipid peroxidation and glutathione levels, catalase (CAT), lactate dehydrogenase (LDH), superoxide dismutase (SOD), and glutathione peroxidase (GPx) activities were determined in liver and intestine tissues. Myeloperoxidase (MPO), aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), γ-glutamyltransferase (GGT) were determined in liver tissue. Also, CAT activity, urea, creatinine, uric acid, and total lipid levels were determined in serum samples. In the ethanol group, serum urea, creatinine, uric acid, and total lipid levels; liver and intestine LDH; liver MPO, AST, ALP, ALT, and GGT activities; and liver and intestine LPO levels increased, whereas serum CAT activity, liver and intestine GSH levels, and CAT, SOD, and GPx activities decreased. On the other hand, treatment with vitamin C, vitamin E, and Se reversed these effects. As a result of these findings, we can say that the combination of vitamin C, vitamin E, and selenium has a protective effect on ethanol-induced changes in lipid peroxidation, glutathione levels, and antioxidant enzyme activities in liver and intestine tissues, and in some serum parameters of rats.
Detrimental Effects of N-Acetylcysteine Plus Desferoxamine Combination in an Experimental Nephrotic Syndrome Model
Authors: Bulucu F. , Oktenli C. , Kenar L. , Koc B. , Ocal R. , Karadurmus N. , Inal V. , Yamanel L. , Sanisoglu Y. S. , Aydin A.
Published: December 2007

The aim of this study was to evaluate the effects of N-acetylcysteine (NAC) and desferoxamine (DFO) administered alone or in combination together in rats with doxorubicin (DOX)-induced nephrotic syndrome, by monitoring oxidative stress parameters and trace elements in renal tissue and erythrocytes. Fifty-four male Sprague-Dawley rats were included the study. Equal volume of isotonic saline was injected to control rats. After DOX administration, the animals were divided into four experimental groups: (a) rats given only DOX; (b) rats treated with NAC; (c) rats treated with DFO; (d) rats treated with NAC plus DFO. The combination of N-acetylcysteine and DFO has no beneficial effect on reducing proteinuria in experimentally nephrotic rats, although both of these agents ameliorate the condition when administered separately. It seems likely that detrimental effects of NAC plus DFO could be secondary to its effects on erythrocyte selenium levels demonstrated here. Consequently, the results may propose caution to the use of antioxidant therapeutic strategies such as NAC plus DFO against nephropathy.
Toxicity of Binary Chemical Munition Destruction Products: Methylphosphonic Acid, Methylphosphinic Acid, 2-Diisopropylaminoethanol, DF Neutralent, and QL Neutralent
Authors: Watson Rebecca E. , Hafez Ahmed M. , Kremsky Jonathan N. , Bizzigotti George O.
Published: December 2007

This paper reports the toxicity and environmental impact of neutralents produced from the hydrolysis of binary chemical agent precursor chemicals DF (methylphosphonic difluoride) and QL (2-[bis(1-methylethyl)amino]ethyl ethyl methylphosphonite). Following a literature review of the neutralent mixtures and constituents, basic toxicity tests were conducted to fill data gaps, including acute oral and dermal median lethal dose assays, the Ames mutagenicity test, and ecotoxicity tests. For methylphosphonic acid (MPA), a major constituent of DF neutralent, the acute oral LD50 in the Sprague-Dawley rat was measured at 1888 mg/kg, and the Ames test using typical tester strains of Salmonella typhimurium and Escherichia coli was negative. The 48-h LC50 values for pH-adjusted DF neutralent with Daphnia magna and Cyprinodon variegatus were >2500 mg/L and 1593 mg/L, respectively. The acute oral LD50 values in the rat for QL neutralent constituents methylphosphinic acid (MP) and 2-diisopropylaminoethanol (KB) were both determined to be 940 mg/kg, and the Ames test was negative for both. Good Laboratory Practice (GLP)-compliant ecotoxicity tests for MP and KB gave 48-h D. magna EC50 values of 6.8 mg/L and 83 mg/L, respectively. GLP-compliant 96-h C. variegatus assays on MP and KB gave LC50 values of 73 and 252 mg/L, respectively, and NOEC values of 22 and 108 mg/L. QL neutralent LD50 values for acute oral and dermal toxicity tests were both > 5000 mg/kg, and the 48-h LD50 values for D. magna and C. variegatus were 249 and 2500 mg/L, respectively. Using these data, the overall toxicity of the neutralents was assessed.
Phospholipase A2 Activation Regulates Cytotoxicity of Methylmercury in Vascular Endothelial Cells
Authors: Mazerik Jessica N , Hagele Thomas , Sherwani Shariq , Ciapala Valorie , Butler Susan , Kuppusamy M Lakshmi , Hunter Melissa , Kuppusamy Periannan , Marsh Clay B , Parinandi Narasimham L.
Published: December 2007

Mercury has been identified as a risk factor for cardiovascular disease among humans. Through diet, mainly fish consumption, humans are exposed to methylmercury, the biomethylated organic form of environmental mercury. As the endothelium is an important player in homeostasis of the cardiovascular system, here, the authors tested their hypothesis that methylmercury activates the lipid signaling enzyme phospholipase A2 (PLA2) in vascular endothelial cells (ECs), causing upstream regulation of cytotoxicity. To test this hypothesis, the authors used bovine pulmonary artery ECs (BPAECs) cultured in monolayers, following labeling of their membrane phospholipids with [3H]arachidonic acid (AA). The cells were exposed to methylmercury chloride (MMC) and then the release of free AA (index of PLA2 activity) and lactate dehydrogenase (LDH; index of cytotoxicity) were determined by liquid scintillation counting and spectrophotometry, respectively. MMC significantly activated PLA2 in a dose-dependent (5 to 15 μM) and time-dependent (0 to 60 min) fashion. Sulfhydryl (thiolprotective) agents, calcium chelators, antioxidants, and PLA2-specific inhibitors attenuated the MMC-induced PLA2 activation, suggesting the role of thiols, reactive oxygen species (ROS), and calcium in the activation of PLA2 in BPAECs. MMC also induced the loss of thiols and increase of lipid peroxidation in BPAECs. MMC induced cytotoxicity in BPAECs as observed by the altered cell morphology and LDH leak, which was significantly attenuated by PLA2 inhibitors. This study established that PLA2 activation through thiols, calcium, and oxidative stress was associated with the cytotoxicity of MMC in BPAECs, drawing attention to the involvement of PLA2 signaling in the methylmercury-induced vascular endothelial dysfunctions.
Mitochondrial Bioenergetics after Nine-Day Treatment Regimen with Benzonidazole in Rats
Authors: Rendon D. A.
Published: December 2007

The bioenergetics of cardiac, liver, and kidney mitochondria after 9-day treatment regimen with benzonidazole was studied in rats. The drug was given by oral gavage to adult male Sprague-Dawley rats for 9 consecutive days (100 mg benzonidazole/kg body weight as daily dose). The assayed mitochondrial bioenergetic parameters were the state 4, state 3, respiratory control, efficiency of oxidative phosphorylation, and the activity of the mitochondrial ATP synthase. The results showed that mitochondrial parameters were not altered statistically after in cardiac and kidney mitochondria, but respiratory control in liver mitochondria was statistically increased with benzonidazole treatment. This change was likely due to a slight decrease in state 4 bioenergy metabolism. These results indicate that 9-day benzonidazole treatment regimen had no negative effect on cardiac, liver, and kidney mitochondrial energy metabolism but increased respiratory control in rat liver mitochondria.
ConoServer, a database for conopeptide sequences and structures
Authors: Kaas Quentin , Westermann Jan-C. , Halai Reena , Wang Conan K. L. , Craik David J.
Published: December 2007

Summary: ConoServer is a new database dedicated to conopeptides, a large family of peptides found in the venom of marine snails of the genus Conus. These peptides have an exceptional diversity of sequences and chemical modifications and their ability to block ion channels makes them important as drug leads and tools for physiological studies. ConoServer uses standardized names and a genetic and structural classification scheme to present data retrieved from SwissProt, GenBank, the Protein DataBank and the literature. The ConoServer web site incorporates specialized features like the graphic display of post-translational modifications that are extensively present in conopeptides. Currently, ConoServer manages 1214 nucleic sequences (from 54 Conus species), 2258 proteic sequences (from 66 Conus species) and 99 3D structures.

Availability:  http://research1t.imb.uq.edu.au/conoserver/

Contact:  d.craik@imb.uq.edu.au
TFBS identification based on genetic algorithm with combined representations and adaptive post-processing
Authors: Chan Tak-Ming , Leung Kwong-Sak , Lee Kin-Hong
Published: December 2007

Motivation: Identification of transcription factor binding sites (TFBSs) plays an important role in deciphering the mechanisms of gene regulation. Recently, GAME, a Genetic Algorithm (GA)-based approach with iterative post-processing, has shown superior performance in TFBS identification. However, the basic GA in GAME is not elaborately designed, and may be trapped in local optima in real problems. The feature operators are only applied in the post-processing, but the final performance heavily depends on the GA output. Hence, both effectiveness and efficiency of the overall algorithm can be improved by introducing more advanced representations and novel operators in the GA, as well as designing the post-processing in an adaptive way.

Results: We propose a novel framework GALF-P, consisting of Genetic Algorithm with Local Filtering (GALF) and adaptive post-processing techniques (-P), to achieve both effectiveness and efficiency for TFBS identification. GALF combines the position-led and consensus-led representations used separately in current GAs and employs a novel local filtering operator to get rid of false positives within an individual efficiently during the evolutionary process in the GA. Pre-selection is used to maintain diversity and avoid local optima. Post-processing with adaptive adding and removing is developed to handle general cases with arbitrary numbers of instances per sequence. GALF-P shows superior performance to GAME, MEME, BioProspector and BioOptimizer on synthetic datasets with difficult scenarios and real test datasets. GALF-P is also more robust and reliable when further compared with GAME, the current state-of-the-art approach.

Availability:  http://www.cse.cuhk.edu.hk/~tmchan/GALFP/

Contact:  tmchan@cse.cuhk.edu.hk

Supplementary information: Supplementary data are available at Bioinformatics online.
Growth of white anglerfish (Lophius piscatorius) tagged in the Northeast Atlantic, and a review of age studies on anglerfish
Authors: Landa Jorge , Duarte Rafael , Quincoces Iñaki
Published: December 2007

Landa, J., Duarte, R., and Quincoces, I. 2008. Growth of white anglerfish (Lophius piscatorius) tagged in the Northeast Atlantic, and a review of age studies on anglerfish. – ICES Journal of Marine Science, 65: 72–80. Growth of white anglerfish was estimated from the results of a tagging study in south European waters. In all, 1326 fish, caught by bottom trawl and gillnet commercial vessels and on trawl surveys, were tagged from 1995 to 2004; 50 were recovered, and a growth rate of 13.6 cm year−1 was estimated from the four fish at liberty long enough to allow extrapolation of the growth rate to an annual period. Growth patterns were reviewed based on available studies of growth verification of white anglerfish in Atlantic waters, including another tag-recapture study, length-frequency of catches, and microstructure analysis of hard parts. The growth rate estimated from these studies showed many similarities, and an overall growth pattern was estimated: growth rate = 18.24e–0.015length. A von Bertalanffy growth curve fitted to all data yielded the parameter values L∞ = 140 cm and k = 0.11. This growth rate is faster than estimated recently using illicia for age estimation, but similar to that found in the first studies that used illicia and sectioned otoliths. Current estimates of growth based on illicia, which are used in assessing the northern European stock of white anglerfish, seem to be underestimated.
Environmental Effects on Oxygen Isotope Enrichment of Leaf Water in Cotton Leaves
Authors: Ripullone Francesco , Matsuo Naoko , Stuart-Williams Hilary , Wong Suan Chin , Borghetti Marco , Tani Makoto , Farquhar Graham
Published: December 2007

The oxygen isotope enrichment of bulk leaf water (Δb) was measured in cotton (Gossypium hirsutum) leaves to test the Craig-Gordon and Farquhar-Gan models under different environmental conditions. Δb increased with increasing leaf-to-air vapor pressure difference (VPd) as an overall result of the responses to the ratio of ambient to intercellular vapor pressures (e  a/e  i) and to stomatal conductance (g  s). The oxygen isotope enrichment of lamina water relative to source water \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(({\bar{{\Delta}}}_{1}),\) \end{document} which increased with increasing VPd, was estimated by mass balance between less enriched water in primary veins and enriched water in the leaf. The Craig-Gordon model overestimated Δb (and \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \({\bar{{\Delta}}}_{1}),\) \end{document} as expected. Such discrepancies increased with increase in transpiration rate (E), supporting the Farquhar-Gan model, which gave reasonable predictions of Δb and \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \({\bar{{\Delta}}}_{1}\) \end{document} with an L of 7.9 mm, much less than the total radial effective length L  r of 43 mm. The fitted values of L for \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \({\bar{{\Delta}}}_{1}\) \end{document} of individual leaves showed little dependence on VPd and temperature, supporting the assumption that the Farquhar-Gan formulation is relevant and useful in describing leaf water isotopic enrichment.
The ACA10 Ca2+-ATPase Regulates Adult Vegetative Development and Inflorescence Architecture in Arabidopsis
Authors: George Lynn , Romanowsky Shawn M. , Harper Jeffrey F. , Sharrock Robert A.
Published: December 2007

The Arabidopsis (Arabidopsis thaliana) compact inflorescence (cif) genotype causes altered adult vegetative development and a reduction in elongation of inflorescence internodes resulting in formation of floral clusters. The cif trait requires both a recessive mutation, cif1, and the activity of a naturally occurring dominant allele of an unlinked gene, CIF2D. We show here that the pseudoverticillata mutation is allelic with cif1 and that the product of the CIF1 gene is ACA10, a member of the large family of P-type Ca2+-ATPases found in higher plants. T-DNA insertion mutations in ACA10, but not in the two other Arabidopsis plasma membrane Ca2+-ATPase-encoding genes, ACA8 and ACA9, cause a cif phenotype when combined with the dominant CIF2D modifier allele. Therefore, ACA10 has a unique function in regulating adult phase growth and inflorescence development. The wild-type ACA8 and ACA10 mRNAs are present at similar levels, and the two promoter-β-glucuronidase fusion transgenes show very similar expression patterns. Moreover, transformation of the cif mutant with an extra copy of the ACA8 gene, which causes overexpression of the ACA8 transcript, can complement the cif phenotype. This suggests that these two Ca2+ pump genes have distinct but related activities and that their differential functions can be altered by relatively small changes in their patterns or levels of expression. The correspondence between cif1 and mutations in ACA10 establishes a genetic link between calcium transport, vegetative phase change, and inflorescence architecture.