bluuebunny/crossref_metadata_2025 huggingface dataset:
Abundance and biology of warty oreo (Allocyttus verrucosus) and spiky oreo (Neocyttus rhomboidalis) (Oreosomatidae) off south-eastern Australia
Authors: Lyle J. M. , Smith D. C.
Published: February 2004

The distribution, abundance, size structure, reproductive biology and diet of warty oreo, Allocyttus verrucosus (Gilchrist), and spiky oreo, Neocyttus rhomboidalis (Gilchrist), from the continental slope region (400-1200 m depth) of south-eastern Australia are described. The depth distributions of the two species overlap, with spiky oreo being more abundant in intermediate depths (600-800 m) and warty oreo abundance peaking at greater depths (900-1200 m). There was evidence of size structuring with depth. Warty oreo juveniles and subadults were comparatively more abundant in depths of less than 1000 m and adults dominated at greater depths. In spiky oreo, juveniles were largely restricted to the depth range of 700-900 m. Size at 50% maturity in females was 28 and 35 cm for warty and spiky oreos, respectively. Males mature at slightly smaller sizes. Spawning occurs in May–June for warty oreo and between August and October for spiky oreo. Just prior to spawning in warty oreo the sexes appear to segregate by depth, with females becoming progressively more dominant with depth. Both species are benthopelagic feeders, consuming a range of prey items including crustaceans, fish and squid. Salps were also an important component of the diet of spiky oreo.
Population modelling of Tasmanian rock lobster, Jasus edwardsii, resources
Authors: Punt André E. , Kennedy Robert B.
Published: February 2004

From 1980 to 1995, annual catch rates of southern rock lobster
(Jasus edwardsii) in Tasmanian waters declined from
1·6 to 0·9 kg per pot lift. From March 1998, the Tasmanian
government intends to base management of this fishery on output controls using
individual transferable catch quotas. This has necessitated the development of
a stock assessment model that can be used to evaluate the relative merits of a
variety of alternative catch limits in terms of the trade-off between
protecting the rock lobster resource and achieving a high yield. Each of eight
regions around Tasmania is assessed separately because of spatial
heterogeneity between regions in lobster growth, size at maturity and catch
rates. The stock assessment model is size-structured and is fitted to catch,
effort and length–frequency data as well as to estimates of exploitation
rate from experimental data. A Bayesian estimation framework is employed to
estimate the quantities needed for risk analysis. Egg production differs
markedly among the eight regions: from as low as 6% of the unexploited
equilibrium level in the northern regions, where the growth rate is fast, to
more than 80% in the south-west, where the growth rate is slowest.
Biochemical composition as a growth predictor in male west-coast rock lobster (Jasus lalandii)
Authors: Cockcroft A. C.
Published: February 2004

The biochemical composition of the hepatopancreas and abdominal muscle tissue
of adult male Jasus lalandii in two size classes was
examined on a monthly and moult-cycle basis over four years to determine the
accumulation and utilization of the major reserves in these tissues. The
possibility of using this information to predict moult increment, defined as
the increase in carapace length, was examined. Two study areas were selected
to provide contrasting information on high and low growth rates, and the
annual moult increments in these areas were determined from tag-and-recapture
studies. The biochemical composition of abdominal muscle did not meet the
prerequisites for a predictive index of growth. Hepatopancreas moisture
content (lowest values measured during accumulation of reserves) showed a
negative correlation with growth increment. Peak lipid content (as both
percentage and absolute values) showed a positive correlation with measured
moult increment. The relationship between percentage of lipid (both size
classes combined) and moult increment was highly significant. Notwithstanding
the limitations introduced by the small number of high-growth data points in
this study, it appears that hepatopancreas lipid content can be used as a
simple and robust predictive indicator of growth in adult male
J. lalandii.
Size structure and reproductive variation of the spiny lobster Panulirus homarus over a relatively small geographic range along the Dhofar coast in the Sultanate of Oman
Authors: Mohan R.
Published: February 2004

This paper reports variations in size structure, size at sexual maturity, and
reproductive potential in the Panulirus homarus
population sampled from commercial catches at three sites: Shuwamiyah, Sudh
and Mugsyl along the Dhofar coast in the Sultanate of Oman. The size structure
of the lobster population showed significant variation
(P < 0.001) among the three sites. Size at sexual
maturity, based on the presence of spermatophores or an ovigerous condition,
indicated variation within the population. Females mature at a smaller size at
Shuwamiyah than they do at Sudh and Mugsyl. The relationship between the
number of eggs (E) and carapace length
(L, in mm) of female lobsters is expressed by
E = –249322 +
8942L (r2
= 0.95; n = 11) over the size range
65–95 mm carapace length. Length frequency, size at sexual maturity, and
fecundity were used to estimate the index of reproductive potential (IRP) of
each 5-mm size class. The size class with the highest IRP varied among the
three sites. The variation in size structure and size at sexual maturity was
explained by fishery exploitation and by different oceanographic and
ecological conditions caused by seasonal upwelling in the study region.
Den sharing by juvenile Caribbean spiny lobsters (Panulirus argus) in nursery habitat: cooperation or coincidence?
Authors: Childress Michael J. , Herrnkind William F.
Published: February 2004

Spiny lobsters (Palinuridae) commonly share crevice shelters with
conspecifics, a behaviour usually hypothesized to benefit mutually cooperative
defenders through reduced predation risk. The group-defence hypothesis
predicts a suite of distinct corollary life history traits and ecological
correlates including more frequent co-denning than solitary denning,
especially where predators or den competitors are numerous and when the
lobsters are small, moulting or otherwise vulnerable. Two alternative
co-denning hypotheses, the dilution effect (a type of selfish herding) and the
guide effect (attraction to a denned conspecific), have different and
distinctive sets of predictions. To test among these hypotheses, the
den-sharing patterns of newly emerged postalgal juveniles of
Panulirus argus and associated ecological conditions in
the Florida Bay (USA) nursery habitat were examined. Only half of the
juveniles shared dens, and rarely was den sharing in an area greater than that
expected by chance. Den-sharing frequency was most highly correlated with
conspecific density and scarcity of local dens. The lack of correlation
between den sharing and lobster size, moult condition, shelter type and
predator density failed to support either the group-defence or the
dilution-effect hypothesis. Instead, the data better support the guide-effect
hypothesis.
Fishery-independent surveys and stock assessment of Panulirus ornatus in Torres Strait
Authors: Pitcher C. Roland , Dennis Darren M. , Skewes Timothy D.
Published: February 2004

The Torres Strait lobster fishery differs culturally and ecologically from
other Australian lobster fisheries. Ornate rock lobsters
(Panulirus ornatus) have been fished by the inhabitants
of Torres Strait for centuries, and commercial fishing began in the late
1960s. The fishery is a major source of income for Torres Strait Islanders,
and the aim of management is to balance the needs of traditional and
commercial users under a treaty between Australia and Papua New Guinea. In
1989, the absolute abundance of lobsters in the main fishing grounds was
estimated by a visual census and a simple assessment was made. Since then,
annual fishery-independent surveys of the relative stock abundance, and catch
sampling, have contributed to the development of a simple cohort dynamics
model of the fishery; for a range of fishing mortalities, it estimates the
potential yield and percentage escapement and has provided annual assessments
of the status of the stock and potential yield one year in advance—
information valuable for managers considering development options and
negotiating catch-sharing agreements and access rights. Future research will
develop the model by incorporating information from ongoing surveys, catch
recording, and logbook data from the Australian and Papua New Guinean
fisheries.
Quantitative relationships between postlarval production and benthic recruitment in lobsters, Homarus americanus
Authors: Incze Lewis S. , Wahle Richard A. , Cobb J. Stanley
Published: February 2004

Relationships between lobster postlarval supply and benthic recruitment were
evaluated within and between oceanographically distinct segments of the range
of the American lobster. Postlarvae (PL) were sampled by neuston nets in
western Rhode Island Sound and the western Gulf of Maine, USA, from June to
September 1989–95. Benthic lobsters were sampled in sublittoral cobble
habitat by using a diver-operated airlift at the end of the settlement season.
Average annual recruitment densities of young-of-year (YOY) lobsters ranged
from 0.3 to 1.7 m-2. YOY recruitment was positively
correlated between areas. Integrated seasonal abundance of postlarvae was
often much greater in Rhode Island than Maine, but production estimates (PL
1000 m-2 season-1), calculated
from moult cycle stages and temperature-dependent growth rates, differed by a
factor of <0.5. PL production was positively correlated between areas and
explained ≥81% of the annual variation in recruitment in each area
and 90% for the two areas combined. In Maine, among-site differences in
YOY recruitment persisted for a year after settlement and then began to
lessen, at least in part because larger individuals moved into areas of
initially lower recruitment
Recruitment strategies in lobsters and crabs: a comparison
Authors: Cobb J. Stanley , Booth John D. , Clancy Michael
Published: February 2004

Early life-history characteristics that affect recruitment in spiny lobsters,
clawed lobsters and crabs of the genus Cancer are
reviewed. Spiny lobsters have many small eggs, a short period of parental
care, and a long larval life that terminates in a swimming postlarva.
Cancer species also have many small eggs, but have a
longer period carrying eggs and a short larval life. Clawed lobsters have
smaller clutches than the other two groups, long parental care and a short
larval period. Acluster analysis on these and other characters in the 16
species considered shows that phylogeny dominates the clustering, because
species of the same family group together. Within families, however, some
possible environmental effects are seen. Spiny lobsters and
Cancer crabs, with greater fecundity and presumably
lower larval survival, may be predicted to have greater recruitment
variability than clawed lobsters. The limited data available suggest that this
is true.
Comparison of data from voluntary logbook and research catch-sampling programmes in the New Zealand lobster fishery
Authors: Starr Paul J. , Vignaux Marianne
Published: February 2004

Since 1993, the New Zealand Fishing Industry Board has run an extensive
voluntary programme to collect biological information from rock lobster
(Jasus edwardsii) pot fisheries using logbooks
maintained by commercial fishers. The New Zealand Ministry of Fisheries has
run since 1989 an intensive research sampling programme of the rock lobster
commercial fishery which measures nearly every lobster caught in a selected
trip. A comparison of these two programmes was made for the southern South
Island fishery over a period from August 1993 to January 1996. Length
frequency distributions stratified by month and statistical area showed
similar distributions from both sampling programmes in most strata, with a
tendency for higher frequency modes to be estimated by the voluntary logbook
data and larger frequency modes estimated by the research sampling data. These
differences were slight except for five instances (of 40 strata compared)
where the research sampling programme estimated flat frequency distributions
which were not typical of the distributions estimated in other strata. Catch
per potlift from the voluntary logbook programme and the compulsory catch per
effort landing returns were similar for the same fishers. This indicated that
the voluntary fishers were successful in designating
‘representative’ sampling units for their programme.
Interpopulational differences in progesterone levels during conception and implantation in humans
Authors: Vitzthum Virginia J. , Spielvogel Hilde , Thornburg Jonathan
Published: February 2004

Clinical studies of women from the United States demonstrate a sensitivity of the ovarian system to energetic stress. Even moderate exercise or caloric restriction can lead to lower progesterone levels and failure to ovulate. Yet women in many nonindustrial populations experience as many as a dozen pregnancies in a lifetime despite poor nutritional resources, heavy workloads, and typical progesterone levels only about two-thirds of those of U.S. women. Previous cross-sectional studies of progesterone may, however, suffer from inadvertent selection bias. In a noncontracepting population, the most fecund women, who might be expected to have the highest progesterone, are more likely to be pregnant or breastfeeding and hence unavailable for a cross-sectional study of the ovarian cycle. The present longitudinal study was designed to ascertain whether lower progesterone also characterizes conception, implantation, and gestation in women from nonindustrialized populations. We compared rural Bolivian Aymara women (
n
= 191) to women from Chicago (
n
= 29) and found that mean-peak-luteal progesterone in the ovulatory cycles of Bolivian women averaged ≈71% that of the women from Chicago. In conception cycles, progesterone levels in Bolivian women during the periovulatory period were ≈63%, and during the peri-implantation period were ≈50%, those of the U.S. women. These observations argue that lower progesterone levels typically characterize the reproductive process in Bolivian women and perhaps others from nonindustrialized populations. We discuss the possible proximate and evolutionary explanations for this variation and note the implications for developing suitable hormonal contraceptives and elucidating the etiology of cancers of the breast and reproductive tract.
Ca
2+
/calmodulin transfers the membrane-proximal lipid-binding domain of the v-SNARE synaptobrevin from cis to trans bilayers
Authors: de Haro Luc , Ferracci Géraldine , Opi Sandrine , Iborra Cécile , Quetglas Stéphanie , Miquelis Raymond , Lévêque Christian , Seagar Michael
Published: February 2004

Soluble
N
-ethylmaleimide-sensitive fusion protein attachment protein receptor (SNARE) protein interactions at the synaptic vesicle/plasma membrane interface play an essential role in neurotransmitter release. The membrane-proximal region (amino acids 77–90) of the v-SNARE vesicle-associated membrane protein 2 (VAMP 2, synaptobrevin) binds acidic phospholipids or Ca
2+
/calmodulin in a mutually exclusive manner, processes that are required for Ca
2+
-dependent exocytosis. To address the mechanisms involved, we asked whether this region of VAMP can interact with cis (outer vesicle leaflet) and/or trans (inner plasma membrane leaflet) lipids. To evaluate cis lipid binding, recombinant VAMP was reconstituted into liposomes and accessibility to site-directed antibodies was probed by surface plasmon resonance. Data indicated that the membrane-proximal domain of VAMP dips into the cis lipid bilayer, sequestering epitopes between the tetanus toxin cleavage site and the membrane anchor. These epitopes were unmasked by VAMP double mutation W89A, W90A, which abolishes lipid interactions. To evaluate trans lipid binding, VAMP was reconstituted in cis liposomes, which were then immobilized on beads. The ability of VAMP to capture protein-free
3
H-labeled trans liposomes was then measured. When cis lipid interactions were eliminated by omitting negatively charged lipids, trans lipid binding to VAMP was revealed. In contrast, when cis and trans liposomes both contained acidic headgroups (i.e., approximating physiological conditions), cis lipid interactions totally occluded trans lipid binding. In these conditions Ca
2+
/calmodulin displaced cis inhibition, transferring the lipid-binding domain of VAMP from the cis to the trans bilayer. Our results suggest that calmodulin acts as a unidirectional Ca
2+
-activated shuttle that docks the juxtamembrane portion of the v-SNARE in the target membrane to prepare fusion.
Heterodimerization of V1a and V2 vasopressin receptors determines the interaction with β-arrestin and their trafficking patterns
Authors: Terrillon Sonia , Barberis Claude , Bouvier Michel
Published: February 2004

V1a vasopressin receptor (V1aR) and V2 vasopressin receptor (V2R) present distinct mechanisms of agonist-promoted trafficking. Although both receptors are endocytosed by way of β-arrestin-dependent processes, β-arrestin dissociates rapidly from V1aR, allowing its rapid recycling to the plasma membrane while β-arrestin remains associated with V2R in the endosomes, leading to their intracellular accumulation. Here, we demonstrate that, when coexpressed, the two receptors can be endocytosed as stable heterodimers. On activation with a nonselective agonist, both receptors cotrafficked with β-arrestin in endosomes where the stable interaction inhibited the recycling of V1aR to the plasma membrane, thus conferring a V2R-like endocytotic/recycling pattern to the V1aR/V2R heterodimer. Coexpression of the constitutively internalized R137HV2R mutant with V1aR was sufficient to promote cointernalization of V1aR in β-arrestin-positive vesicles even in the absence of agonist stimulation. This finding indicates that internalization of the heterodimer does not require activation of each of the protomers. Consistent with this notion, a V1aR-selective agonist led to the coendocytosis of V2R. In that case, however, the V1aR/V2R heterodimer was not stably associated with β-arrestin, and both receptors were recycled back to the cell surface, indicating that the complex followed the V1aR endocytotic/recycling path. Taken together, these results suggest that heterodimerization regulates the endocytotic processing of G protein-coupled receptors and that the identity of the activated protomer within the heterodimer determines the fate of the internalized receptors.
Single-nucleotide promoter polymorphism alters transcription of neuronal nitric oxide synthase exon 1c in infantile hypertrophic pyloric stenosis
Authors: Saur Dieter , Vanderwinden Jean-Marie , Seidler Barbara , Schmid Roland M. , De Laet Marc-Henri , Allescher Hans-Dieter
Published: February 2004

Infantile hypertrophic pyloric stenosis (IHPS), characterized by enlarged pyloric musculature and gastric-outlet obstruction, is associated with altered expression of neuronal nitric oxide synthase (nNOS). Here we have studied molecular mechanisms by which nNOS gene expression is altered in pyloric tissues of 16 infants with IHPS and 9 controls. A significant decreased expression of total nNOS mRNA was found by quantitative RT-PCR in IHPS after normalization against GAPDH, which predominantly affected exon 1c with a reduction of 88% compared with controls (
P
< 0.001). After normalization against the neuronal-specific gene PGP9.5, expression of exon 1c was still decreased (
P
< 0.001), whereas expression of exon 1f was increased significantly (
P
= 0.001), indicating a compensatory up-regulation of this nNOS mRNA variant. DNA samples of 16 IHPS patients and 81 controls were analyzed for nNOS exon 1c promoter mutations and single-nucleotide polymorphism (SNP). Sequencing of the 5′-flanking region of exon 1c revealed mutations in 3 of 16 IHPS tissues, whereas 81 controls showed the wild-type sequence exclusively. Carriers of the A allele of a previously uncharacterized nNOS exon 1c promoter SNP (-84G → A) had increased risk for development of IHPS (odds ratio, 8.0; 95% confidence interval, 2.5–25.6). Reporter gene assays revealed an unchanged promoter activity for mutations but a ≈30% decrease for the -84A SNP (
P
< 0.001). In summary, our findings indicate that genetic alterations in the nNOS exon 1c regulatory region influence expression of the nNOS gene and may contribute to the pathogenesis of IHPS.
NMR structure of the KaiC-interacting C-terminal domain of KaiA, a circadian clock protein: Implications for KaiA–KaiC interaction
Authors: Vakonakis Ioannis , Sun Jingchuan , Wu Tianfu , Holzenburg Andreas , Golden Susan S. , LiWang Andy C.
Published: February 2004

KaiA is a two-domain circadian clock protein in cyanobacteria, acting as the positive element in a feedback loop that sustains the oscillation. The structure of the N-terminal domain of KaiA is that of a
pseudo
-receiver, similar to those of bacterial response regulators, which likely interacts with components of the clock-resetting pathway. The C-terminal domain of KaiA is highly conserved among cyanobacteria and enhances the autokinase activity of KaiC. Here we present the NMR structure of the C-terminal domain of KaiA from the thermophilic cyanobacterium
Thermosynechococcus elongatus
BP-1. This domain adopts a novel all α-helical homodimeric structure. Several mutations known to affect the period of the circadian oscillator are shown to be located at an exposed groove near the dimer interface. This NMR structure and a 21-Å-resolution electron microscopy structure of the hexameric KaiC particle allow us to postulate a mode of KaiA–KaiC interaction, in which KaiA binds a linker region connecting two globular KaiC domains.
Rapid modulation of osteoblast ion channel responses by 1α,25(OH)
2
-vitamin D
3
requires the presence of a functional vitamin D nuclear receptor
Authors: Zanello Laura P. , Norman Anthony W.
Published: February 2004

1α,25(OH)
2
-Vitamin D
3
(1,25D) modulates osteoblast gene expression of bone matrix proteins via a nuclear vitamin D receptor (VDR) and also modifies the electrical state of the plasma membrane through rapid nongenomic mechanisms still not fully understood. The physiological significance of 1,25D membrane-initiated effects remains unclear. To elucidate whether the VDR is required for 1,25D-promoted electrical responses, we studied 1,25D modulation of ion channel activities in calvarial osteoblasts isolated from VDR knockout (KO) and WT mice. At depolarizing potentials, Cl
-
currents were significantly potentiated (13.5 ± 1.6-fold increase,
n
= 12) by 5 nM 1,25D in VDR WT but not in KO (0.96 ± 0.3 fold increase,
n
= 11) osteoblasts. L-type Ca
2+
currents significantly shift their peak activation by -9.3 ± 0.7 mV (
n
= 10) in the presence of 5 nM 1,25D in VDR WT but not in KO cells, thus facilitating Ca
2+
influx. Furthermore, we found that 1,25D significantly increased wholecell capacitance in VDR WT (ΔCap = 2.3 ± 0.4 pF,
n
= 8) but not in KO osteoblasts (ΔCap = 0.3 ± 0.1 pF,
n
= 8); this corresponds to a rapid (1–2 min) fusion in WT of 71 ± 33 versus in KO only 9 ± 6 individual secretory granules. We conclude that, in calvarial osteoblasts, 1,25D modulates ion channel activities only in cells with a functional VDR and that this effect is coupled to exocytosis. This is a demonstration of the requirement of a functional classic steroid receptor for the rapid hormonal modulation of electric currents linked to secretory activities in a target cell.
Cytogenetic evidence for asexual evolution of bdelloid rotifers
Authors: Welch Jessica L. Mark , Welch David B. Mark , Meselson Matthew
Published: February 2004

DNA sequencing has shown individual bdelloid rotifer genomes to contain two or more diverged copies of every gene examined and has revealed no closely similar copies. These and other findings are consistent with long-term asexual evolution of bdelloids. It is not entirely ruled out, however, that bdelloid genomes consist of previously undetected pairs of sequences so similar as to be identical over the regions sequenced, as might result if bdelloids were highly inbred sexual diploids or polyploids. Here, we employ fluorescentin situhybridization with cosmid probes to determine the copy number and chromosomal distribution of the heat shock genehsp82and adjacent sequences in the bdelloidPhilodina roseola. We conclude that the four copies identified by sequencing are the only ones present and that each is on a separate chromosome. Bdelloids therefore are not highly homozygous sexually reproducing diploids or polyploids.
A pituitary gene encodes a protein that produces differentiation of breast and prostate cancer cells
Authors: Platica Micsunica , Ivan Elena , Holland James F. , Ionescu Alin , Chen Sheryl , Mandeli John , Unger Pamela D. , Platica Ovidiu
Published: February 2004

A cDNA clone of 1.1 kb encoding a 108-aa polypeptide was isolated from a human pituitary cDNA library by expression cloning. This protein was named tumor differentiation factor (TDF). The recombinant TDF protein and a 20-aa peptide, P1, selected from the ORF of the gene, induced morphological and biochemical changes consistent with differentiation of human breast and prostate cancer cells. Fibroblast, kidney, hepatoma, and leukemic lymphocytic cell lines were unaffected. Breast and prostate cancer cells aggregated in spheroid-like structures within 24 h of exposure to TDF. This effect was abrogated by a specific affinity-purified rabbit polyclonal anti-P1 Ab. E-cadherin expression was increased in a dose-dependent manner by TDF. Treatment of MCF7 cells with TDF led to production of a lactalbumin-related protein. Peptide P1 significantly decreased the growth of androgen-independent DU145 prostate cancer in severe combined immunodeficient mice. The presence of TDF protein in human sera was detected by the anti-P1 Ab, suggesting a role of TDF in endocrine metabolism. The fact that all activities of TDF can be mimicked by a peptide derived from the encoding TDF sequence opens the possibility of therapeutic applications.
Notch is required for long-term memory in
Drosophila
Authors: Presente Asaf , Boyles Randy S. , Serway Christine N. , de Belle J. Steven , Andres Andrew J.
Published: February 2004

A role for
Notch
in the elaboration of existing neural processes is emerging that is distinct from the increasingly well understood function of this gene in binary cell-fate decisions. Several research groups, by using a variety of organisms, have shown that
Notch
is important in the development of neural ultrastructure. Simultaneously,
Presenilin
(
Psn
) was identified both as a key mediator of Notch signaling and as a site of genetic lesions that cause early-onset Alzheimer's disease. Here we demonstrate that
Notch
loss of function produces memory deficits in
Drosophila melanogaster
. The effects are specific to long-term memory, which is thought to depend on ultrastructural remodeling. We propose that Notch plays an important role in the neural plasticity underlying consolidated memory.
Signal transduction pathways that inhibit hepatitis B virus replication
Authors: Robek Michael D. , Boyd Bryan S. , Wieland Stefan F. , Chisari Francis V.
Published: February 2004

The replication of hepatitis B virus (HBV) in hepatocytes is strongly inhibited in response to IFN-α/β and IFN-γ. Although it has been previously demonstrated that IFN-α/β eliminates HBV RNA-containing capsids from the cell in a proteasome-dependent manner, the precise cellular pathway that mediates this antiviral effect has not been identified. Because IFN-induced signal transduction involves kinase-mediated activation of gene expression, we used an immortalized hepatocyte cell line that replicates HBV in an IFN-sensitive manner to investigate the role of cellular kinase activity and the cellular transcription and translation machinery in the antiviral effect. Our results indicate that Janus kinase activity is required for the antiviral effect of IFN against HBV, but that phosphatidylinositol 3-kinase, cyclin-dependent kinase, mitogen-activated protein kinase, and NF-κB activity are not. Additionally, we found that inhibitors of cellular transcription and translation completely abolish the antiviral effect, which also appears to require cellular kinase activity downstream of signal transduction and gene expression. Collectively, these results identify IFN-regulated pathways that interrupt the HBV replication cycle by eliminating viral RNA-containing capsids from the cell, and they provide direction for discovery of the terminal effector molecules that ultimately mediate this antiviral effect.
Diet, nutrition and the prevention of cancer
Authors: Key Timothy J , Schatzkin Arthur , Willett Walter C , Allen Naomi E , Spencer Elizabeth A , Travis Ruth C
Published: February 2004

Objective:

To assess the epidemiological evidence on diet and cancer and make public health recommendations.

Design:

Review of published studies, concentrating on recent systematic reviews, meta-analyses and large prospective studies.

Conclusions and recommendations:

Overweight/obesity increases the risk for cancers of the oesophagus (adenocarcinoma), colorectum, breast (postmenopausal), endometrium and kidney; body weight should be maintained in the body mass index range of 18.5–25?kg/m2, and weight gain in adulthood avoided. Alcohol causes cancers of the oral cavity, pharynx, oesophagus and liver, and a small increase in the risk for breast cancer; if consumed, alcohol intake should not exceed 2?units/d. Aflatoxin in foods causes liver cancer, although its importance in the absence of hepatitis virus infections is not clear; exposure to aflatoxin in foods should be minimised. Chinese-style salted fish increases the risk for nasopharyngeal cancer, particularly if eaten during childhood, and should be eaten only in moderation. Fruits and vegetables probably reduce the risk for cancers of the oral cavity, oesophagus, stomach and colorectum, and diets should include at least 400?g/d of total fruits and vegetables. Preserved meat and red meat probably increase the risk for colorectal cancer; if eaten, consumption of these foods should be moderate. Salt preserved foods and high salt intake probably increase the risk for stomach cancer; overall consumption of salt preserved foods and salt should be moderate. Very hot drinks and foods probably increase the risk for cancers of the oral cavity, pharynx and oesophagus; drinks and foods should not be consumed when they are scalding hot. Physical activity, the main determinant of energy expenditure, reduces the risk for colorectal cancer and probably reduces the risk for breast cancer; regular physical activity should be taken.
Induction of Tumor-specific T Cell Immunity by Anti-DR5 Antibody Therapy
Authors: Takeda Kazuyoshi , Yamaguchi Noriko , Akiba Hisaya , Kojima Yuko , Hayakawa Yoshihiro , Tanner Jane E. , Sayers Thomas J. , Seki Naoko , Okumura Ko , Yagita Hideo , Smyth Mark J.
Published: February 2004

Because tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) preferentially induces apoptosis in tumor cells and plays a critical role in tumor surveillance, its receptor is an attractive target for antibody-mediated tumor therapy. Here we report that a monoclonal antibody (mAb) against the mouse TRAIL receptor, DR5, exhibited potent antitumor effects against TRAIL-sensitive tumor cells in vivo by recruiting Fc receptor–expressing innate immune cells, with no apparent systemic toxicity. Administration of the agonistic anti-DR5 mAb also significantly inhibited experimental and spontaneous tumor metastases. Notably, the anti-DR5 mAb-mediated tumor rejection by innate immune cells efficiently evoked tumor-specific T cell immunity that could also eradicate TRAIL-resistant variants. These results suggested that the antibody-based therapy targeting DR5 is an efficient strategy not only to eliminate TRAIL-sensitive tumor cells, but also to induce tumor-specific T cell memory that affords a long-term protection from tumor recurrence.
p38 MAPK-induced Nuclear Factor-κB Activity Is Required for Skeletal Muscle Differentiation: Role of Interleukin-6
Authors: Baeza-Raja Bernat , Muñoz-Cánoves Pura
Published: February 2004

p38 MAPK and nuclear factor-κB (NF-κB) signaling pathways have been implicated in the control of skeletal myogenesis. However, although p38 is recognized as a potent activator of myoblast differentiation, the role of NF-κB remains controversial. Here, we show that p38 is activated only in differentiating myocytes, whereas NF-κB activity is present both in proliferation and differentiation stages. NF-κB activation was found to be dependent on p38 activity during differentiation, being NF-κB an effector of p38, thus providing a novel mechanism for the promyogenic effect of p38. Activation of p38 in C2C12 cells induced the activity of NF-κB, in a dual way: first, by reducing IκBα levels and inducing NF-κB-DNA binding activity and, second, by potentiating the transactivating activity of p65-NF-κB. Finally, we show that interleukin (IL)-6 expression is induced in C2C12 differentiating myoblasts, in a p38- and NF-κB-dependent manner. Interference of IL-6 mRNA reduced, whereas its overexpression increased, the extent of myogenic differentiation; moreover, addition of IL-6 was able to rescue significantly the negative effect of NF-κB inhibition on this process. This study provides the first evidence of a crosstalk between p38 MAPK and NF-κB signaling pathways during myogenesis, with IL-6 being one of the effectors of this promyogenic mechanism.
The C Terminus of Peripherin/rds Participates in Rod Outer Segment Targeting and Alignment of Disk Incisures
Authors: Tam Beatrice M. , Moritz Orson L. , Papermaster David S.
Published: February 2004

Protein targeting is essential for domain specialization in polarized cells. In photoreceptors, three distinct membrane domains exist in the outer segment: plasma membrane, disk lamella, and disk rim. Peripherin/retinal degeneration slow (rds) and rom-1 are photoreceptor-specific members of the transmembrane 4 superfamily of transmembrane proteins, which participate in disk morphogenesis and localize to rod outer segment (ROS) disk rims. We examined the role of their C termini in targeting by generating transgenic Xenopus laevis expressing green fluorescent protein (GFP) fusion proteins. A GFP fusion containing residues 317-336 of peripherin/rds localized uniformly to disk membranes. A longer fusion (residues 307-346) also localized to the ROS but exhibited higher affinity for disk rims than disk lamella. In contrast, the rom-1 C terminus did not promote ROS localization. The GFP-peripherin/rds fusion proteins did not immunoprecipitate with peripherin/rds or rom-1, suggesting this region does not form intermolecular interactions and is not involved in subunit assembly. Presence of GFP-peripherin/rds fusions correlated with disrupted incisures, disordered ROS tips, and membrane whorls. These abnormalities may reflect competition of the fusion proteins for other proteins that interact with peripherin/rds. This work describes novel roles for the C terminus of peripherin/rds in targeting and maintaining ROS structure and its potential involvement in inherited retinal degenerations.
c-Fos Activated Phospholipid Synthesis Is Required for Neurite Elongation in Differentiating PC12 Cells
Authors: Gil Germán A. , Bussolino Daniela F. , Portal Maximiliano M. , Pecchio Adolfo Alfonso , Renner Marianne L. , Borioli Graciela A. , Guido Mario E. , Caputto Beatriz L.
Published: February 2004

We have previously shown that c-Fos activates phospholipid synthesis through a mechanism independent of its genomic AP-1 activity. Herein, using PC12 cells induced to differentiate by nerve growth factor, the genomic effect of c-Fos in initiating neurite outgrowth is shown as distinct from its nongenomic effect of activating phospholipid synthesis and sustaining neurite elongation. Blocking c-Fos expression inhibited differentiation, phospholipid synthesis activation, and neuritogenesis. In cells primed to grow, blocking c-Fos expression determined neurite retraction. However, transfected cells expressing c-Fos or c-Fos deletion mutants with capacity to activate phospholipid synthesis sustain neurite outgrowth and elongation in the absence of nerve growth factor. Results disclose a dual function of c-Fos: it first releases the genomic program for differentiation and then associates to the endoplasmic reticulum and activates phospholipid synthesis. Because phospholipids are key membrane components, we hypothesize this latter phenomenon as crucial to support membrane genesis demands required for cell growth and neurite elongation.
The Oxa2 Protein ofNeurospora crassaPlays a Critical Role in the Biogenesis of Cytochrome Oxidase and Defines a Ubiquitous Subbranch of the Oxa1/YidC/Alb3 Protein Family
Authors: Funes Soledad , Nargang Frank E. , Neupert Walter , Herrmann Johannes M.
Published: February 2004

Proteins of the Oxa1/YidC/Alb3 family mediate the insertion of proteins into membranes of mitochondria, bacteria, and chloroplasts. Here we report the identification of a second gene of the Oxa1/YidC/Alb3 family in the genome of Neurospora crassa, which we have named oxa2. Its gene product, Oxa2, is located in the inner membrane of mitochondria. Deletion of the oxa2 gene caused a specific defect in the biogenesis of cytochrome oxidase and resulted in induction of the alternative oxidase (AOD), which bypasses the need for complex IV of the respiratory chain. The Oxa2 protein of N. crassa complements Cox18-deficient yeast mutants suggesting a common function for both proteins. The oxa2 sequence allowed the identification of a new subfamily of Oxa1/YidC/Alb3 proteins whose members appear to be ubiquitously present in mitochondria of fungi, plants, and animals including humans.
Role of the hprT–ftsH locus in Staphylococcus aureus
Authors: Lithgow James K. , Ingham Eileen , Foster Simon J.
Published: February 2004

The roles of two adjacent genes in theStaphylococcus aureuschromosome with functions in starvation survival and the response to stressful conditions have been characterized. One of these,hprT, encoding a hypoxanthine–guanine phosphoribosyltransferase homologue, was initially identified in a transposon mutagenesis screen. Mutation ofhprTaffects starvation survival in amino-acid-limiting conditions and the ability ofS. aureusto grow in high-salt concentrations. Downstream ofhprTisftsH, which encodes a membrane-bound, ATP- and Zn2+-dependent ‘AAA’-type protease. Mutation offtsHinS. aureusleads to pleiotropic defects including slower growth, sensitivity to salt, acid, methyl viologen and potassium tellurite stresses, and reduced survival in amino-acid- or phosphate-limiting conditions. BothhprT–lacZandftsH–lacZgene fusions are expressed maximally in the post-exponential phase of growth. Although secretion of exoproteins is not affected, anftsHmutant is attenuated in a murine skin lesion model of pathogenicity.
CtaG is required for formation of active cytochrome c oxidase in Bacillus subtilis
Authors: Bengtsson Jenny , von Wachenfeldt Claes , Winstedt Lena , Nygaard Per , Hederstedt Lars
Published: February 2004

The Gram-positive bacteriumBacillus subtiliscontains two respiratory oxidases of the haem-copper superfamily: cytochromeaa3, which is a quinol oxidase, and cytochromecaa3, which is a cytochromecoxidase. Cytochromecoxidase uniquely contains a di-copper centre, CuA.B. subtilisCtaG is a membrane protein encoded by the same gene cluster as that which encodes the subunits of cytochromecoxidase. The role ofB. subtilisCtaG and orthologous proteins present in many other Gram-positive bacteria has remained unexplored. The sequence of CtaG is unrelated to that of CtaG/Cox11p of proteobacteria and eukaryotic cells. This study shows thatB. subtilisCtaG is essential for the formation of active cytochromecaa3but is not required for assembly of the core subunits I and II with haem in the membrane and it has no role in the synthesis of active cytochromeaa3.B. subtilisYpmQ, a homologue to Sco1p of eukaryotic cells, is also a membrane-bound cytochromecoxidase-specific assembly factor. Properties of CtaG- and YpmQ-deficient mutants were compared. Cells lacking YpmQ showed a low cytochromecoxidase activity and this defect was suppressed by the supplementation of the growth medium with copper ions. It has previously been proposed that YpmQ/Sco1p is involved in synthesis of the CuAcentre. The results of this study are consistent with this proposal but the exact role of YpmQ in assembly of cytochromecoxidase remains to be elucidated.
RT-PCR detection of Candida albicans ALS gene expression in the reconstituted human epithelium (RHE) model of oral candidiasis and in model biofilms
Authors: Green Clayton B. , Cheng Georgina , Chandra Jyotsna , Mukherjee Pranab , Ghannoum Mahmoud A. , Hoyer Lois L.
Published: February 2004

An RT-PCR assay was developed to analyse expression patterns of genes in the Candida albicans ALS (agglutinin-like sequence) family. Inoculation of a reconstituted human buccal epithelium (RHE) model of mucocutaneous candidiasis with strain SC5314 showed destruction of the epithelial layer by C. albicans and also formation of an upper fungal layer that had characteristics similar to a biofilm. RT-PCR analysis of total RNA samples extracted from C. albicans-inoculated buccal RHE showed that ALS1, ALS2, ALS3, ALS4, ALS5 and ALS9 were consistently detected over time as destruction of the RHE progressed. Detection of transcripts from ALS7, and particularly from ALS6, was more sporadic, but not associated with a strictly temporal pattern. The expression pattern of ALS genes in C. albicans cultures used to inoculate the RHE was similar to that observed in the RHE model, suggesting that contact of C. albicans with buccal RHE does little to alter ALS gene expression. RT-PCR analysis of RNA samples extracted from model denture and catheter biofilms showed similar gene expression patterns to the buccal RHE specimens. Results from the RT-PCR analysis of biofilm RNA specimens were consistent between various C. albicans strains during biofilm development and were comparable to gene expression patterns in planktonic cells. The RT-PCR assay described here will be useful for analysis of human clinical specimens and samples from other disease models. The method will provide further insight into the role of ALS genes and their encoded proteins in the diverse interactions between C. albicans and its host.
Phospholipid synthesis in Borrelia burgdorferi: BB0249 and BB0721 encode functional phosphatidylcholine synthase and phosphatidylglycerolphosphate synthase proteins
Authors: Wang Xing-Guo , Scagliotti Joanna P. , Hu Linden T.
Published: February 2004

Phospholipids are an important component of bacterial membranes.Borrelia burgdorferidiffers from many other bacteria in that it contains only two major membrane phospholipids: phosphatidylglycerol (PG) and phosphatidylcholine (PC).B. burgdorferiappears to lack enzymes required for synthesis of PC through the well-described methylation pathway. However,B. burgdorferidoes contain a gene (BB0249) with significant identity to a recently described phosphatidylcholine synthase gene (pcs) ofSinorhizobium meliloti. B. burgdorferialso contains a gene (BB0721) with significant identity to the gene (pgs) encoding phosphatidylglycerolphosphate synthase, an enzyme in the synthetic pathway of PG. Activity of BB0249 was confirmed by cloning the gene intoEscherichia coli, which does not produce PC. Transformation with a plasmid carryingBB0249resulted in production of PC byE. coli, but only in the presence of exogenously supplied choline, as would be predicted for a Pcs. Because loss of Pgs activity is lethal toE. coli, activity ofBB0721was confirmed by the ability of BB0721 to complement anE. coliPgs−mutant. A plasmid containingBB0721was transformed into a Pgs−mutant ofE. colicontaining a copy of the native gene on a temperature-regulated plasmid. The temperature-regulated plasmid was exchanged for a plasmid containingBB0721and it was shown that BB0721 was able to replace the lost Pgs function and restore bacterial growth. This study has established the existence and function of two critical enzymes in the synthesis of PC and PG inB. burgdorferi. Understanding of the biosynthetic pathways of PC and PG inB. burgdorferiis the first step in delineating the role of these phospholipids in the pathogenesis of Lyme disease.
In vivo target of a transcriptional activator revealed by fluorescence resonance energy transfer
Authors: Bhaumik Sukesh R. , Raha Tamal , Aiello David P. , Green Michael R.
Published: February 2004

Our understanding of eukaryotic transcriptional activation mechanisms has been hampered by an inability to identify the direct in vivo targets of activator proteins, primarily because of lack of appropriate experimental methods. To circumvent this problem, we have developed a fluorescence resonance energy transfer (FRET) assay to monitor interactions with transcriptional activation domains in living cells. We use this method to show that the Tra1 subunit of the SAGA (Spt/Ada/Gcn5/acetyltransferase) complex is the direct in vivo target of the yeast activator Gal4. Chromatin-immunoprecipitation experiments demonstrate that the Gal4-Tra1 interaction is required for recruitment of SAGA to the upstream activating sequence (UAS), and SAGA, in turn, recruits the Mediator complex to the UAS. The UAS-bound Mediator is required for recruitment of the general transcription factors to the core promoter. Thus, our results identify the in vivo target of an activator and show how the activator-target interaction leads to transcriptional stimulation. The FRET assay we describe is a general method that can be used to identify the in vivo targets of other activators.
Cooperativity in long-range gene regulation by the λ CI repressor
Authors: Dodd Ian B. , Shearwin Keith E. , Perkins Alison J. , Burr Tom , Hochschild Ann , Egan J. Barry
Published: February 2004

Effective repression of cI transcription from PRM by the bacteriophage λ CI repressor requires binding sites (OL) located 2.4 kb from the promoter. A CI tetramer bound to OL1.OL2 interacts with a tetramer bound near PRM (OR1.OR2), looping the intervening DNA. We previously proposed that in this CI octamer:DNA complex, the distant OL3 operator and the weak OR3 operator overlapping PRM are juxtaposed so that a CI dimer at OL3 can cooperate with a CI dimer binding to OR3. Here we show that OL3 is necessary for effective repression of PRM and that the repressor at OL3 appears to interact specifically with the repressor at OR3. The OL3-CI-OR3 interaction involves the same CI interface used for short-range dimer-dimer interactions and does not occur without the other four operators. The long-range interactions were incorporated into a physicochemical model, allowing estimation of the long-range interaction energies and showing the lysogenic state to be ideally poised for CI negative autoregulation. The results establish the λ system as a powerful tool for examining long-range gene regulatory interactions in vivo.
Requirement of protein phosphatase 5 in DNA-damage-induced ATM activation
Authors: Ali Ambereen , Zhang Ji , Bao Shideng , Liu Irene , Otterness Diane , Dean Nicholas M. , Abraham Robert T. , Wang Xiao-Fan
Published: February 2004

The checkpoint kinase ATM is centrally involved in the cellular response to DNA double-strand breaks. However, the mechanism of ATM activation during genotoxicstress is only partially understood. Here we report a direct regulatory linkage between the protein serine-threonine phosphatase 5 (PP5) and ATM. PP5 interacts with ATM in a DNA-damage-inducible manner. Reduced expression of PP5 attenuated DNA-damage-induced activation of ATM. Expression of a catalytically inactive PP5 mutant inhibited the phosphorylation of ATM substrates and the autophosphorylation of ATM on Ser 1981, and caused an S-phase checkpoint defect in DNA-damaged cells. Together our findings indicate that PP5 plays an essential role in the activation and checkpoint signaling functions of ATM in cells that have suffered DNA double-strand breaks.