bluuebunny/crossref_metadata_2025 huggingface dataset:
Distribution and habitat of the northern hopping-mouse, Notomys aquilo
Authors: Woinarski J. C. Z. , Gambold N. , Fisher A. , Wurst D. , Flannery T. F. , Smith A. P. , Chatto R.
Published: January 2006

Current documentation and specimen data for
Notomys aquilo are restricted to three localities: Cape
York (one record from the nineteenth century), Groote Eylandt, and central
Arnhem Land (one record). A field survey based on signs of
N. aquilo and Aboriginal information indicated that the
species occurs widely on sandy substrates of Arnhem Land. Recent observation
of signs suggests that it may also persist on Cape York Peninsula. The species
is reasonably common on Groote Eylandt, where it was recorded most frequently
in shrublands (dominated by either Acacia spp.,
Hakea arborescens or
Banksia dentata), but occurred also in coastal
grasslands and other strand vegetation. Its abundance there is associated with
the cover of hummock grass and several pea species. The conservation status of
the species appears to be secure.
Bait uptake by foxes (Vulpes vulpes) in urban Melbourne: the potential of oral vaccination for rabies control
Authors: Marks Clive A. , Bloomfield Tim E.
Published: January 2006

Red foxes (Vulpes vulpes) are widely distributed
throughout the Melbourne metropolitan area. Density estimates indicate that
fox populations would be capable of maintaining the endemic persistence of
rabies. Oral vaccination of foxes by baiting is a technique that has been used
successfully overseas to manage rabies epizootics. This study assessed the
uptake by foxes of baits containing biomarkers in three urban field sites in
winter 1993 and summer 1993/94. Baits were dosed with 200 mg of
tetracycline in the winter trial and 5 mg of iophenoxic acid in the summer
trial, and distributed at a density of 8 baits ha
−1 in open areas within each field site. In the
winter trial, 8 of 11 (72.7%) radio-collared foxes known to be in the
field sites during the distribution of baits were marked. In the summer trial,
45 of the 49 foxes (92%) recovered from the combined field sites had
consumed at least a single bait, resulting in bait acceptance of
80–97% for each field site. No bias existed between plasma iodine
levels due to sex, although first-year foxes had a significantly higher level
than older age groups combined. There were no significant differences in mean
age of foxes collected at the three field sites, yet significant differences
existed in mean plasma iodine concentrations between all three sites. These
results are discussed with reference to rabies contingency planning. The high
rates of bait uptake in this study are encouraging and suggest that oral
vaccination may be a viable strategy for rabies containment in urban areas and
is worthy of further assessment at reduced baiting densities.
The diet of itinerant male Hooker's sea lions, Phocarctos hookeri, at sub-Antarctic Macquarie Island
Authors: McMahon Clive R. , Holley Dave , Robinson Susan
Published: January 2006

Scats were collected from itinerant male Hooker's sea lions,
Phocarctos hookeri, at Macquarie Island and the uneroded
faunal remains used to assess the diet. Uneroded sagittal otoliths were used
to identify teleost fish and to calculate fish size. Prey items included 14
taxa of teleost fish, cephalopods, gastropods, crustaceans and fur seals. Fish
constituted the primary component of the diet. Prey species previously
uncommon in the diet of seals and penguins around Macquarie Island were
commonly eaten by Hooker's sea lions. The sub-Antarctic horse fish
(Zanclorhynchus spinifer) and the Patagonian tooth fish
(Dissostichus eleginoides) were the two most abundant
species and occurred in 62.5% and 41.7% of all scats
respectively. There were no age-specific and individual differences in the
diet of sea lions. Seasonal variances in diet were absent. Small plastic
fragments (diameter ∼1 mm) were found only in association with otoliths of
Electrona subaspera. Some overlap was seen between the
diet of itinerant male Hooker's sea lions and the commercial fisheries
that currently operate around Macquarie Island.
Tree species preferences of koalas (Phascolarctos cinereus) in the Campbelltown area south-west of Sydney, New South Wales
Authors: Phillips Stephen , Callaghan John
Published: January 2006

Tree species preferences of a koala population inhabiting a small area of
forest and woodland in the Campbelltown area, south-west of Sydney, were
investigated over a two-year period. In total, 2499 trees from 45 independent
field sites were assessed, with tree species preferences determined on the
basis of a comparative analysis of proportional data relating to the
presence/absence of koala faecal pellets. The results established that
grey gum (Eucalyptus punctata) and blue-leaved
stringybark (E. agglomerata) were most preferred by
koalas in the study area, but only when growing on shale-based substrates. The
preferential utilisation of E. punctata and
E. agglomerata on substrates derived from shales,
compared with that recorded for the same species on sandstones, suggests that
their use by koalas was influenced by differences in nutrient status between
substrates. Regression analyses further identified a trend for use of at least
one of the preferred species (E. punctata) to be more
commonly associated with larger trees. Results are discussed in terms of their
relevance to issues of resource availability and the need to reconsider, by
way of a hierarchical approach, the use of food trees by koalas generally. The
presence of E. punctata and
E. agglomerata and their occurrence in conjunction with
shale-based substrates are considered to be important limiting factors
affecting the present-day distribution and abundance of koalas in the
Campbelltown area.
Morphological change and fat accumulation in juvenile red foxes (Vulpes vulpes) in the Central Tablelands of New South Wales
Authors: Winstanley Roy K.
Published: January 2006

Juvenile red foxes (Vulpes vulpes) reach sexual
maturation within 10 months of parturition. During this time juveniles need to
manage their energy reserves to fuel maintenance metabolism, growth and
reproduction. To determine juvenile growth rates and body energy reserves, I
measured body mass, morphology, and estimated body fat, in free-living red
foxes from approximately 8 weeks of age through to 1 year old. Foxes
(n = 163) were sampled monthly from August 1995
to July 1996 in the Central Tablelands of New South Wales.
Mean body mass of male and female juvenile foxes was indistinguishable from
adult body mass by February, at 16 weeks of age (males 4500 g, females 4200
g). Skeletal measurements of body and forelimb length in both sexes also
attained adult proportions by February. Further changes in morphology were
minimal in first-year foxes.
Total body fat was estimated indirectly using a kidney fat index. Estimated
juvenile body fat remained low and stable (6%) in both sexes from
December through March. Male body fat peaked in August (11%) but was
low in July during mating and also September and October whilst females were
denning. Estimated body fat of females peaked in August–September
(13%) but declined sharply in October after parturition. In addition,
73% of first-year females sampled during August–October were
either pregnant or had recently given birth.
Effects of the Iron Baron oil spill on little penguins (Eudyptula minor). I. Estimates of mortality
Authors: Goldsworthy S. D. , Gales R. P. , Giese M. , Brothers N.
Published: January 2006

The bulk ore carrier Iron Baron ran aground on Hebe Reef
at the mouth of the Tamar River in northern Tasmania, Australia, on 10 July
1995. It released an estimated 325 tonnes of bunker fuel oil. Of the wildlife
species affected, the most readily detected was the little penguin
(Eudyptula minor); 1894 were collected and treated for
oiling. This study estimates the impact of the oil spill on populations of
little penguins. At Ninth Island (approximately 40 km from Hebe Reef), one of
the most affected little penguin colonies, pre-oil-spill population estimates
were available. Extensive regular trapping and mark–recapture of birds
at this site during the course of the oil spill provided longitudinal data on
oiling rates from a known population size. Using these data, we estimate that
19.6% of birds from Ninth Island were oiled and survived to come
ashore. This represents about 526 (1932–3108, 95% CL) adult
birds, or up to 5566 (4197–6917) birds in total (adults and juveniles).
For estimates of the impact on little penguin populations in the region, we
provide three scenarios of the possible numbers of penguins oiled. After
considering the biases of each risk assessment, we believe that between 10 000
and 20 000 penguins were killed as a result of the oil spill. The study
indicates that, despite the relatively small amount of oil spilt by the
Iron Baron, the impact on penguin populations was
extensive. This study also highlights the difficulties and requirements in
assessing the impact of oil spills on wildlife populations.
Cholinergic and adrenergic innervation of lingual salt glands of the estuarine crocodile, Crocodylus porosus
Authors: Franklin Craig E. , Taylor Greg , Cramp Rebecca L.
Published: January 2006

Many marine reptiles and birds possess extrarenal salt glands that facilitate the excretion of excess sodium and chloride ions accumulated as a consequence of living in saline environments. Control of the secretory activity of avian salt glands is under neural control, but little information is available on the control of reptilian salt glands. Innervation of the lingual salt glands of the salt water crocodile, Crocodylus porosus, was examined in salt water-acclimated animals using histological methods. Extensive networks of both cholinergic and adrenergic nerve fibres were identified close to salt-secreting lobules and vasculature. The identification of both catecholamine-containing and cholinergic neurons in the salt gland epithelium and close to major blood vessels in the tissue suggests the action of the neurotransmitters on the salt-secreting epithelium itself and the rich vascular network of the lingual salt glands.
Life history and reproductive ecology of White's skink, Egernia whitii
Authors: Chapple DG
Published: January 2006

The life history and reproductive ecology of White’s skink, Egernia whitii, was examined in a population in the Australian Capital Territory using both field and genetic studies. Colour pattern polymorphism was evident within the population, with both patterned and plain-back morphs present. Lizards typically took 3 years to reach sexual maturity, with the size at maturity being ~75 mm snout–vent length (SVL) in both sexes. There was an even overall adult sex ratio, although a slight female-bias was evident in plain-back individuals. Sexual dimorphism was evident, with males having longer and wider heads, and females having larger body size. Females generally bred annually, with mating occurring in September–October and parturition in late January–February, although the litter was produced over several days (2–10 days, mean 4 days). Litter size ranged from one to four (mean of 2.5). There was a significant relationship between maternal SVL and both litter size and relative clutch mass, but these trends were not consistent between colour morphs. An inverse relationship between litter size and offspring size (SVL and mass) was found. Comparison of the results with previous investigations of E. whitii indicates substantial geographic variation in life-history traits that is presumably associated with latitudinal variation in climatic conditions.
Ecology of the common marsupial tick (Ixodes tasmani Neumann) (Acarina : Ixodidae), in eastern Australia
Authors: Murdoch Fiona A. , Spratt David M.
Published: January 2006

Ixodes tasmani is one of the most common and widespread of the Australian species of Ixodes and a vector of zoonotic rickettsial diseases. The tick was reared successfully in the laboratory; the entire life cycle was completed in 4 months. A diurnal rhythm of detachment from captive hosts (laboratory Rattus norvegicus) was observed for all stages and, combined with other evidence, suggests that I. tasmani is nidicolous. The prevalence and intensity of tick infestation on wild-caught, common brushtail possums (Trichosurus vulpecula), was least during the summer months. To investigate questing activity, laboratory-reared nymphs were held in enclosures in one sheltered (tree hollows) and three exposed (vegetation) microhabitats. Questing was continuous but at low intensity in tree hollows, and nocturnal and at an increased (higher) intensity in vegetation. The observed questing activity appeared to maximise host contact with T. vulpecula, which is nocturnal but retires by day to tree hollows. Field and laboratory observations suggest that the risk for humans of tick-bite from I. tasmani and consequent transmission of zoonotic diseases may be low compared with the risk from other tick species.
Construction of a marsupial bacterial artificial chromosome library from the model Australian marsupial, the tammar wallaby (Macropus eugenii)
Authors: Sankovic Natasha , Bawden Wayne , Martyn John , Graves Jennifer A. M. , Zuelke Kurt
Published: January 2006

With the accelerating recognition of the power of comparative genomics, there is now enormous interest in sequencing the genomes of a broad range of species. Marsupials diverged at an important evolutionary time. The model Australian marsupial, the tammar wallaby (Macropus eugenii), has long been a resource for biological and genetic studies of marsupials, and the availability of a bacterial artificial chromosome (BAC) library will be a valuable resource in these studies. A tammar wallaby BAC library was constructed using pRazorBAC vector. It contains 55 296 clones with an average insert size of 108 kb, representing 2.2 times coverage of the wallaby genome (based on an estimated 2.7 × 109 bp haploid genome size). The library was arrayed in 384-well plates, and spotted in duplicate onto nylon membranes. Screening these membranes has yielded clones containing 34 single-copy genes distributed over the genome, while it failed for only one gene. Each probe isolated 1–12 BAC clones and, to date, no chimeric clones have been found. This BAC library will constitute an invaluable resource for creating physical maps, positional cloning of genes and other sequences in the tammar wallaby, as well as comparative mapping studies in mammals.
Contrasting lifetime patterns of territorial success in the nymphalid butterflies Hypolimnas bolina and Melanitis leda: a question of flight physiology?
Authors: Kemp Darrell J.
Published: January 2006

Territorial behaviour is widespread among insects and serves as an important constituent of male reproductive success. In butterflies, competition for perching sites is mediated through aerial persistence duels in which the mechanisms of resolution have remained obscure. There is evidence in some species for an effect of age upon contest outcome, which could arise due to individuals adopting lifetime strategies of reproductive risk taking, or as a consequence of lifetime changes in resource-holding potential (RHP). RHP in territorial insects is often equated to the ability for sustained or high-performance flight, and if the morphological and/or energetic determinants of flight performance vary with age then this may explain putative age effects. I addressed this possibility by charting the correlates of residency in two nymphalid species, Hypolimnas bolina L. and Melanitis leda L., at popular perching sites in tropical Australia. Among samples of 55 male H. bolina (20 residents paired to 35 non-residents) and 36 male M. leda (13 residents paired to 23 non-residents), I found moderately sized relationships (effect sizes, d = 0.46–0.79) between residency and the studied biophysical variables (body size, absolute and relative lipid stores, and relative flight musculature). However, differences in age were always much larger (effect sizes, d = 1.23–1.52), with old male H. bolina and young male M. leda favoured for residency. The most parsimonious logistic model of residency in each case proved to be the model containing age only; hence, this study supports the notion of primarily age-based competitive strategies in these two butterflies.
Seasonal variation in rates of sporocyst and metacercarial infection by Brachylaima cribbi in helicid and hygromiid land snails on the Yorke Peninsula, South Australia
Authors: Butcher A. R. , Grove D. I.
Published: January 2006

Brachylaima cribbi is a terrestrial trematode parasite of humans and other mammals, birds and reptiles, with helicid and hygromiid summer-aestivating land snails acting as first and second intermediate hosts. Beginning in April, seasonal variations in rates of sporocyst and metacercarial infection by B. cribbi were studied in Cochlicella acuta, Cernuella virgata and Theba pisana over 1 year at four ecologically diverse sites on the Yorke Peninsula, South Australia. The overall mean sporocyst prevalence rate in April was 2.7%. Sporocyst prevalences peaked during spring (10–78% for C. acuta, 12–44% for C. virgata and 10–18% for T. pisana). Metacercarial infection rates varied markedly from 10% to 98% at the start of the study. Overall metacercarial infection rates peaked with winter rains for T. pisana (average 50% infected) and in spring for C. acuta and C. virgata (average 80% infected) then declined in summer for all species. The average numbers of metacercariae per infected snail over the study period were 5.4 for C. virgata, 3.9 for C. acuta and 2.2 for T. pisana, with maximum numbers in winter or spring. Conditions on the Yorke Peninsula favour hyperinfection with this parasite.
Rate of passage of digesta through the alimentary tract of the New Zealand fur seal (Arctocephalus forsteri) and the Australian sea lion (Neophoca cinerea) (Carnivora : Otariidae)
Authors: Bodley B. , Mercer the late J. R. , Bryden M. M.
Published: January 2006

The inert marker titanium dioxide was added to the food of two male New
Zealand fur seals (Arctocephalus forsteri) and three
Australian sea lions (Neophoca cinerea) in Taronga Zoo,
Sydney, in a series of 15 trials. The enclosures were checked constantly
during daylight hours, and defaecation times and location of samples noted.
Samples were collected at feeding times, at approximately 0930, 1300 and 1500
hours. During the night the animals were checked at 30-min intervals, the
location of samples noted, and samples collected at the first feeding time
next morning. Faecal collections were made for up to 50 h after dosing. Marker
concentrations in faecal dry matter were determined and mean retention times
calculated from the mean concentration-time curves.
The mean time between dosing and first recovery of marker (Initial Recovery
Time) was 4 h for A. forsteri and 6.5 h for
N. cinerea. Mean retention time, a better index of rate
of passage of digesta, was 14.6 h for A. forsteri and
14.9 h for N. cinerea. Thus, the marker concentration
curves indicated a rapid rate of food transit through the gastrointestinal
tract, as has been observed in several (but not all) pinniped species.
Effect of sloughing and digestion on metabolic rate in the Australian carpet python, Morelia spilota imbricata
Authors: Thompson Graham G. , Withers Philip C.
Published: January 2006

The standard metabolic rate for juvenile carpet pythons,
Morelia spilota imbricata, with a mean body mass of
129.6 g (range 57.7–253 g) increased from 6.75 ± 0.96 (s.e.) mL
h–1 to 42.6 ± 12.40 (s.e.) mL
h–1 in 48 h after ingesting mice equal to
approximately 23% of their body mass, at a temperature of 30°C.
Sloughing increased metabolic rate to approximately 146% of standard
metabolic rate at 30°C. Metabolic rate is elevated before the eyes become
opaque and other visual signs indicate that a slough is imminent. The
implications of these two factors when measuring standard metabolic rate are
discussed.
Habitat and nest-site partitioning in splendid and variegated fairy-wrens (Aves : Maluridae)
Authors: Tibbetts Elizabeth , Pruett-Jones Stephen
Published: January 2006

Territory size, interspecific interactions, foraging behaviour, habitat use,
and nest placement were examined in sympatric populations of splendid
(Malurus splendens melanotus) and variegated
(M. lamberti assimilis) fairy-wrens. Although these
species have similar patterns of life history and biology, they utilise
different microhabitats within overlapping territories. Splendid fairy-wrens
spent more time on the ground and in open areas, whereas variegated
fairy-wrens generally preferred higher and more protected locations. The two
species exhibited a similar pattern of separation with respect to foraging
behaviour, as splendid fairy- wrens mainly foraged on the ground whereas
variegated fairy-wrens preferred bushes. They also partitioned nesting
habitat, with splendid fairy-wrens building nests in areas with a greater
density of trees than variegated fairy-wrens. Further, splendid fairy-wrens
built nests in larger shrubs and farther from the edge of these bushes than
variegated fairy-wrens. We suggest that these differences in habitat use
decrease interspecific competition between the two species.
The relationships between brain regions and forelimb dexterity in marsupials (Marsupialia): a comparative test of the principle of proper mass
Authors: Iwaniuk Andrew N. , Nelson John E. , Whishaw Ian Q.
Published: January 2006

A behavioural index of forelimb dexterity and comparative statistics were used
to analyse the relationships between proximal (shoulder, upper and lower
forelimb) and distal (wrist, forepaw, digits) forelimb dexterity and four
aspects of brain morphology (overall brain, cortex, cerebellum and
telencephalon sizes) in 18 species of marsupials. On the basis of the
principle of proper mass, it was expected that an increase in forelimb
dexterity (either proximal or distal) would be positively correlated with the
size of the brain and the three brain components. Using independent contrast
analysis to remove the effects of phylogeny revealed three significant
correlations between: cortex size and distal dexterity, cerebellum size and
proximal dexterity, and telencephalon size and distal dexterity. The
relationship between cortex size and distal dexterity was subsequently
corroborated by Spearman rank correlations. These results suggest that the
execution of finely coordinated forelimb movements may not be dependent upon
overall brain size, but may be dependent upon the size of brain components,
thus supporting the principle of proper mass.
Are roadside strips important reservoirs of invertebrate diversity? A comparison of the ant and beetle faunas of roadside strips and large remnant woodlands
Authors: Major Richard E. , Smith Derek , Cassis Gerasimos , Gray Michael , Colgan Donald J.
Published: January 2006

Pitfall traps were used to sample the terrestrial ant and beetle fauna of four
large State Forests and five roadside strips of white cypress pine woodland in
the wheat belt of central western New South Wales. In total, 93 morphospecies
of ant and 82 morphospecies of beetle were identified. The species richness
and total abundance of both ants and beetles did not differ significantly
between roadside strips and large State Forests.
Multivariate analyses detected significant differences in community
composition of the ant and beetle faunas of large State Forests and roadside
strips of vegetation. Differences in ant community composition were similar
regardless of whether the analysis was conducted at the species or genus
level. Differences in beetle community composition were significant at the
family level, but not at the species level, possibly because sampling
intensity at the species level was sub-optimal.
There was no significant correlation between ant species richness and beetle
species richness, nor between total abundance of ants and total abundance of
beetles. However, there was a significant correlation between site similarity
assessed according to ant community composition and beetle community
composition.
Of the species found in the large State Forests (presumed woodland species),
69% of ant species and 64% of beetle species were found in
roadside strips of vegetation. This suggests that even though the two habitat
configurations may support different communities, narrow strips of vegetation
still represent useful habitat for many species of woodland invertebrates.
They therefore have considerable potential both as conduits of gene flow and
as reservoirs of biodiversity in highly fragmented landscapes
Life history and demography of an uncooperative Australian passerine, the brown thornbill
Authors: Green David J. , Cockburn Andrew
Published: January 2006

The genus Acanthiza may be important in understanding
the evolution of avian mating systems because while brown thornbills,
Acanthiza pusilla, are thought to breed only in pairs, a
recent phylogenetic analysis suggests that cooperative breeding is the
ancestral trait within this genus. We provide a detailed account of the
breeding biology of the brown thornbill, confirm that they breed exclusively
in pairs, and compare their population demography with what is known for other
members of the Pardalotidae. We found that brown thornbills produced small
clutches (3 eggs) with a two-day laying interval, had a long incubation period
(declining from 19 to 16 days through the season), and had a long breeding
season (4.0 months) that allowed females to occasionally raise two successful
broods. Brown thornbills, in our study, produced an average of 1.57 fledglings
per pair and had relatively high annual survival rates
(c. 63%). We found no evidence to suggest that
the evolution of pair-breeding within the Pardalotidae is associated with a
reduction in annual survival rates, a short breeding season with reduced
productivity, or high levels of predation post-fledging. Since there also
appear to be no ecological correlates with mating system in the Pardalotidae
we suggest that examination of reproductive conflict between parents and young
may shed light on the evolution of pairbreeding in this family.
On the mechanical behavior of WS
2
nanotubes under axial tension and compression
Authors: Kaplan-Ashiri Ifat , Cohen Sidney R. , Gartsman Konstantin , Ivanovskaya Viktoria , Heine Thomas , Seifert Gotthard , Wiesel Inna , Wagner H. Daniel , Tenne Reshef
Published: January 2006

The mechanical properties of materials and particularly the strength are greatly affected by the presence of defects; therefore, the theoretical strength (≈10% of the Young's modulus) is not generally achievable for macroscopic objects. On the contrary, nanotubes, which are almost defect-free, should achieve the theoretical strength that would be reflected in superior mechanical properties. In this study, both tensile tests and buckling experiments of individual WS
2
nanotubes were carried out in a high-resolution scanning electron microscope. Tensile tests of MoS
2
nanotubes were simulated by means of a density-functional tight-binding-based molecular dynamics scheme as well. The combination of these studies provides a microscopic picture of the nature of the fracture process, giving insight to the strength and flexibility of the WS
2
nanotubes (tensile strength of ≈16 GPa). Fracture analysis with recently proposed models indicates that the strength of such nanotubes is governed by a small number of defects. A fraction of the nanotubes attained the theoretical strength indicating absence of defects.
High-speed microfluidic differential manometer for cellular-scale hydrodynamics
Authors: Abkarian Manouk , Faivre Magalie , Stone Howard A.
Published: January 2006

We propose a broadly applicable high-speed microfluidic approach for measuring dynamical pressure-drop variations along a micrometer-sized channel and illustrate the potential of the technique by presenting measurements of the additional pressure drop produced at the scale of individual flowing cells. The influence of drug-modified mechanical properties of the cell membrane is shown. Finally, single hemolysis events during flow are recorded simultaneously with the critical pressure drop for the rupture of the membrane. This scale-independent measurement approach can be applied to any dynamical process or event that changes the hydrodynamic resistance of micro- or nanochannels.
Identification of a receptor-independent activator of G protein signaling (AGS8) in ischemic heart and its interaction with Gβγ
Authors: Sato Motohiko , Cismowski Mary J. , Toyota Eiji , Smrcka Alan V. , Lucchesi Pamela A. , Chilian William M. , Lanier Stephen M.
Published: January 2006

As part of a broader effort to identify postreceptor signal regulators involved in specific diseases or organ adaptation, we used an expression cloning system in
Saccharomyces cerevisiae
to screen cDNA libraries from rat ischemic myocardium, human heart, and a prostate leiomyosarcoma for entities that activated G protein signaling in the absence of a G protein coupled receptor. We report the characterization of activator of G protein signaling (AGS) 8 (KIAA1866), isolated from a rat heart model of repetitive transient ischemia. AGS8 mRNA was induced in response to ventricular ischemia but not by tachycardia, hypertrophy, or failure. Hypoxia induced AGS8 mRNA in isolated adult ventricular cardiomyocytes but not in rat aortic smooth muscle cells, endothelial cells, or cardiac fibroblasts, suggesting a myocyte-specific adaptation mechanism involving remodeling of G protein signaling pathways. The bioactivity of AGS8 in the yeast-based assay was independent of guanine nucleotide exchange by Gα, suggesting an impact on subunit interactions. Subsequent studies indicated that AGS8 interacts directly with Gβγ and this occurs in a manner that apparently does not alter the regulation of the effector PLC-β
2
by Gβγ. Mechanistically, AGS8 appears to promote G protein signaling by a previously unrecognized mechanism that involves direct interaction with Gβγ.
HTLV-I basic leucine zipper factor
gene mRNA supports proliferation of adult T cell leukemia cells
Authors: Satou Yorifumi , Yasunaga Jun-ichirou , Yoshida Mika , Matsuoka Masao
Published: January 2006

Human T cell leukemia virus type I (HTLV-I) causes adult T cell leukemia (ATL) in 2–5% of carriers after a long latent period. An HTLV-I encoded protein, Tax, induces proliferation and inhibits apoptosis, resulting in clonal proliferation of infected cells. However,
tax
gene expression in ATL cells is disrupted by several mechanisms, including genetic changes in the
tax
gene and DNA methylation/deletion of the 5′ long terminal repeat (LTR). Because Tax is the major target of cytotoxic T-lymphocytes
in vivo
, loss of Tax expression should enable ATL cells to escape the host immune system. The 5′ LTR of HTLV-I is frequently hypermethylated or deleted in ATL cells, whereas the 3′ LTR remains unmethylated and intact, suggesting the involvement of the 3′ LTR in leukemogenesis. Here we show that a gene encoded by the minus strand of the HTLV-I proviral genome,
HTLV-I basic leucine zipper factor
(
HBZ
), is transcribed from 3′-LTR in all ATL cells. Suppression of
HBZ
gene transcription by short interfering RNA inhibits proliferation of ATL cells. In addition,
HBZ
gene expression promotes proliferation of a human T cell line. Analyses of T cell lines transfected with mutated
HBZ
genes showed that
HBZ
promotes T cell proliferation in its RNA form, whereas HBZ protein suppresses Tax-mediated viral transcription through the 5′ LTR. Thus, the single
HBZ
gene has bimodal functions in two different molecular forms. The growth-promoting activity of
HBZ
RNA likely plays an important role in oncogenesis by HTLV-I.
A family with erythrocytosis establishes a role for prolyl hydroxylase domain protein 2 in oxygen homeostasis
Authors: Percy Melanie J. , Zhao Quan , Flores Adrian , Harrison Claire , Lappin Terence R. J. , Maxwell Patrick H. , McMullin Mary Frances , Lee Frank S.
Published: January 2006

The number of red blood cells is normally tightly regulated by a classic homeostatic mechanism based on oxygen sensing in the kidney. Decreased oxygen delivery resulting from anemia induces the production of erythropoietin, which increases red cell production and hence oxygen delivery. Investigations of erythropoietin regulation identified the transcription factor hypoxia-inducible factor (HIF). HIF is now recognized as being a key regulator of genes that function in a comprehensive range of processes besides erythropoiesis, including energy metabolism and angiogenesis. HIF itself is regulated through the α-subunit, which is hydroxylated in the presence of oxygen by a family of three prolyl hydroxylase domain proteins (PHDs)/HIF prolyl hydroxylases/egg-laying-defective nine enzymes. Hydroxylation allows capture by the von Hippel–Lindau tumor suppressor gene product, ubiquitination, and destruction by the proteasome. Here we describe an inherited mutation in a mammalian PHD enzyme. We show that this mutation in PHD2 results in a marked decrease in enzyme activity and is associated with familial erythrocytosis, identifying a previously unrecognized cause of this condition. Our findings indicate that PHD2 is critical for normal regulation of HIF in humans.
ChxR is a transcriptional activator in
Chlamydia
Authors: Koo Ingrid Chou , Walthers Don , Hefty P. Scott , Kenney Linda J. , Stephens Richard S.
Published: January 2006

Chlamydia
spp. are obligate intracellular bacterial pathogens that alternate between two metabolically and morphologically distinct developmental forms, and differentiation depends on transcriptional regulation. Genome sequencing of
Chlamydia trachomatis
revealed an ORF, CT630 (
chxR
), whose amino acid sequence contains a winged helix–turn–helix motif similar to the DNA-binding domain of response regulators in the OmpR subfamily. ChxR differs from many response regulators in that essential residues in the receiver or phosphorylation domain are lacking. ChxR functions as a transcriptional regulator because it activated transcription of
ompF
and
ompC
when expressed in
Escherichia coli
.
In vitro
transcription combined with microarray analysis also demonstrated that ChxR activates its own expression by binding directly to sites upstream of
chxR
; it also activates
infA
,
tufA
,
oppA
, and
CT084
. DNase I protection studies showed that ChxR bound to sites in the
ompF
and
ompC
promoter proximal regions that overlap but were distinct from OmpR binding sites. Both proteins could bind simultaneously to their nonoverlapping binding sites. This report identifies a stage-specific transcriptional regulator and some of its target genes in
Chlamydia
.
Distribution of histone H3.3 in hematopoietic cell lineages
Authors: Jin Chunyuan , Felsenfeld Gary
Published: January 2006

We have introduced the histone variant H3.3 into chicken erythroid cell lines and examined its distribution in the neighborhood of the folate receptor (FR) and β-globin genes by using high-resolution chromatin immunoprecipitation (ChIP). Marked incorporation of tagged H3.3 into the FR gene is confined to its upstream regulatory region and is observed whether or not the gene is transcriptionally active. Incorporation is also observed over locus control regulatory elements in the absence of transcription of genes regulated by these elements, suggesting that gene activity
per se
is not necessarily required to replace H3 with H3.3. Other active genes display various behaviors, either incorporating H3.3 over both the coding region and upstream regulatory region or over upstream sequences only. There is, however, no straightforward correlation between sites of H3.3 incorporation and regions of enrichment in H3 acetylation and lysine-4 methylation. In the case of FR and VEGF-D, in which incorporation is confined to upstream regions, the presence of exogenous H3 results in reduced expression, whereas H3.3 stimulates expression. This finding suggests that these histone variants can be active rather than passive participants in regulation of expression.
Revised direct radiocarbon dating of the Vindija G
1
Upper Paleolithic Neandertals
Authors: Higham Tom , Ramsey Christopher Bronk , Karavanić Ivor , Smith Fred H. , Trinkaus Erik
Published: January 2006

The 1998/1999 direct dating of two Neandertal specimens from level G
1
of Vindija Cave in Croatia to ≈28,000 and ≈29,000 radiocarbon (
14
C) years ago has led to interpretations concerning the late survival of Neandertals in south-central Europe, patterns of interaction between Neandertals and in-dispersing early modern humans in Europe, and complex biocultural scenarios for the earlier phases of the Upper Paleolithic. Given improvements, particularly in sample pretreatment techniques for bone radiocarbon samples, especially ultrafiltration of collagen samples, these Vindija G
1
Neandertal fossils are redated to ≈32,000–33,000
14
C years ago and possibly earlier. These results and the recent redating of a number of purportedly old modern human skeletal remains in Europe to younger time periods highlight the importance of fine chronological control when studying this biocultural time period and the tenuous nature of monolithic scenarios for the establishment of modern humans and earlier phases of the Upper Paleolithic in Europe.
Two types of cytotoxic lymphocyte regulation explain kinetics of immune response to human immunodeficiency virus
Authors: Rouzine I. M. , Sergeev R. A. , Glushtsov A. I.
Published: January 2006

The organization of the cytotoxic T lymphocyte (CTL) response at organismal level is poorly understood. We propose a mathematical model describing the interaction between HIV and its host that explains 20 quantitative observations made in HIV-infected individuals and simian immunodeficiency virus-infected monkeys, including acute infection and response to various antiretroviral therapy regimens. The model is built on two modes of CTL activation: direct activation by infected cells and indirect activation by CD4 helper cells activated by small amounts of virus. Effective infection of helper cells by virus leads to a stable chronic infection at high virus load. We assume that CTLs control virus by killing infected cells. We explain the lack of correlation between the CTL number and the virus decay rate in therapy and predict that individuals with a high virus load can be switched to a low-viremia state that will maintain stability after therapy, but the switch requires fine adjustment of therapy regimen based on the model and individual parameters.
Biochemical basis for dominant mutations in the Saccharomyces cerevisiae MSH6 gene
Authors: Hess Martin T. , Mendillo Marc L. , Mazur Dan J. , Kolodner Richard D.
Published: January 2006

Here, the ATP-binding, ATP hydrolysis, mispair-binding, sliding clamp formation, and Mlh1–Pms1 complex interaction properties of dominant mutant Msh2–Msh6 complexes have been characterized. The results demonstrate two mechanisms for dominance. In one, seen with the Msh6-S1036P and Msh6-G1067D mutant complexes, the mutant complex binds mispaired bases, is defective for ATP-induced sliding clamp formation and assembly of ternary complexes with Mlh1-Pms1, and occludes mispaired bases from other mismatch repair pathways. In the second, seen with the Msh6–G1142D complex, the mutant complex binds mispaired bases and is defective for ATP-induced sliding clamp formation but assembles ternary complexes with Mlh1–Pms1 that either occlude the mispaired base or prevent Mlh1–Pms1 from acting in alternate mismatch repair pathways.
ATRIP associates with replication protein A-coated ssDNA through multiple interactions
Authors: Namiki Yuka , Zou Lee
Published: January 2006

The ATR (ATM- and rad3-related)-mediated checkpoint pathway has a crucial role in regulating the cellular responses to DNA damage and DNA-replication stress. ATRIP (ATR-interacting protein), the regulatory partner of ATR, binds directly to replication protein A (RPA)-coated ssDNA and enables the ATR–ATRIP complex to recognize this DNA damage-induced structure. Here, we show that ATRIP associates with RPA–ssDNA through multiple interactions. Two major RPA–ssDNA-interacting domains of ATRIP were mapped to the regions flanking the conserved coiled-coil domain. In contrast to a recent article, we found that ATRIP mutants lacking the N terminus retained the ability to bind to RPA–ssDNA, suggesting that the multiple interactions between ATRIP and RPA–ssDNA may function redundantly in the recruitment of ATR–ATRIP. Unexpectedly, one internal region of ATRIP exhibited affinity to ssDNA, suggesting that ATRIP may interact with ssDNA in the ATRIP–RPA–ssDNA complex. Also, the N terminus of ATRIP associated with RPA–ssDNA in two distinct ways, indicating a dynamic and regulated association between ATRIP and RPA–ssDNA.
Germ-line induction of the
Caenorhabditis elegans
vulva
Authors: Thompson Beth E. , Lamont Liana B. , Kimble Judith
Published: January 2006

Development of the
Caenorhabditis elegans
vulva serves as a paradigm for intercellular signaling during animal development. In wild-type animals, the somatic gonadal anchor cell generates the LIN-3/EGF ligand to induce vulval fates in the underlying hypodermis, whereas FBF, FOG-1, and FOG-3 control germ-line development. Here we report that FBF functions redundantly with FOG-1 and FOG-3 to control vulval induction: animals lacking FBF and either FOG-1 or FOG-3 have multiple vulvae, the Muv phenotype. The
fog; fbf
Muv phenotype is generated by aberrant induction of vulval precursor cells (VPCs): in wild-type animals, three VPCs are induced to form a single vulva, but, in
fog; fbf
mutants, four or five VPCs are typically induced, resulting in ectopic vulvae. Laser ablation experiments and mosaic analyses demonstrate that the germ line is critical for the
fog; fbf
Muv phenotype. Consistent with that site of action, we detect FBF and FOG-1 in the germ line but not in the VPCs. The simplest interpretation is that FOG-1, FOG-3, and FBF act in the germ line to influence vulval fates. The LIN-3/EGF ligand may be the germ-line signal to the VPCs: the
fog; fbf
Muv phenotype depends on LIN-3 activity, and the
lin-3
3′ UTR possesses an FBF binding element. Our findings reveal new insights into germ line-to-soma signals and the role of PUF proteins in animal development.
Cryptic species within the cosmopolitan desiccation-tolerant moss
Grimmia laevigata
Authors: Fernandez Catherine C. , Shevock James R. , Glazer Alexander N. , Thompson John N.
Published: January 2006

The common cushion moss
Grimmia laevigata
(Bridel) Bridel grows on bare rock in a broad range of environments on every continent except Antarctica. As such, it must harbor adaptations to a remarkably broad set of environmental stresses, the extremes of which can include very high temperatures, prolonged nearly complete desiccation, and high ultraviolet B (UVB) exposure. Yet, like many mosses,
G. laevigata
shows very little morphological variability across its cosmopolitan range. This presents an evolutionary puzzle, the solution to which lies in understanding the phylogeographic structure of this morphologically simple organism. Here we report the results of an analysis of amplified fragment length polymorphisms (AFLPs) in
G. laevigata
, focusing on individuals from the California Floristic Province. We found evidence that populations within California constitute two distinct geographically overlapping cryptic species. Each clade harbors multiple private alleles, indicating they have been genetically isolated for some time. We suggest that the existence of cryptic species within
G. laevigata
, in combination with its life history, growth habits, and extreme desiccation tolerance, makes this moss an ideal research tool and a candidate for a biological indicator of climate change and pollution.
Antagonistic effect of CCAAT enhancer-binding protein-α and Pax5 in myeloid or lymphoid lineage choice in common lymphoid progenitors
Authors: Hsu Chia-Lin , King-Fleischman Angela G. , Lai Anne Y. , Matsumoto Yukie , Weissman Irving L. , Kondo Motonari
Published: January 2006

Lymphoid lineage-committed progenitors, such as common lymphoid progenitors (CLPs), maintain a latent myeloid differentiation potential, which can be initiated by stimulation through exogenously expressed cytokine receptors, including IL-2 receptors. Here we show that the transcription factor CCAAT enhancer-binding protein-α (C/EBPα) is promptly up-regulated in CLPs upon ectopic IL-2 stimulation. Enforced C/EBPα expression is sufficient to initiate myeloid differentiation from CLPs, as well as from proT and proB cells, even though proB cells do not give rise to myeloid cells after ectopic IL-2 stimulation. Expression of Pax5, a B lymphoid-affiliated transcription factor, is completely suppressed by enforced C/EBPα but not by ectopic IL-2 stimulation in proB cells. Introduction of Pax5 blocks ectopic IL-2 receptor-mediated myeloid lineage conversion in CLPs. These data suggest that C/EBPα is a proximal target of cytokine-induced lineage conversion in lymphoid progenitors. Furthermore, complete loss of Pax5 expression triggered by up-regulation of C/EBPα is a critical event for lineage conversion from lymphoid to myeloid lineage in CLPs and proB cells.
Influence of iothalamate on renal medullary perfusion and oxygenation in the rat
Authors: Liss P. , Aukland K. , Carlsson P.-O. , Palm F. , Hansell P.
Published: January 2006

Purpose: To evaluate controversial results regarding the effect of the contrast medium (CM) iothalamate on renal medullary blood flow by applying two different methods simultaneously.

Material and Methods: The outer medullary blood flow (OMBF) response was estimated using laser-Doppler flowmetry and hydrogen gas wash-out (microelectrodes) simultaneously. Outer medullary oxygen tension (PO2) was measured using Clark type microelectrodes. Iothalamate was injected i.v. at 1600 mg I/kg body weight for 2 min.

Results: CM induced a transient 28% decrease in OMBF as measured with the laser Doppler. The hydrogen gas wash-out rate was reduced by 50%, indicating a reduced perfusion. CM induced a transient 60% reduction in PO2, while renal fluid and electrolyte excretion increased several fold.

Conclusion: The CM iothalamate reduces outer medullary perfusion as estimated by two different techniques applied simultaneously. The PO2 in the same region was also reduced. Previous controversies regarding the effect of iothalamate on OMBF can be explained by extreme dosage and injection rates greatly exceeding clinical relevance.