bluuebunny/crossref_metadata_2025 huggingface dataset:
A nicotinic acetylcholine receptor mutation conferring target-site resistance to imidacloprid inNilaparvata lugens(brown planthopper)
Authors: Liu Zewen , Williamson Martin S. , Lansdell Stuart J. , Denholm Ian , Han Zhaojun , Millar Neil S.
Published: June 2005

Neonicotinoids, such as imidacloprid, are nicotinic acetylcholine receptor (nAChR) agonists with potent insecticidal activity. Since its introduction in the early 1990s, imidacloprid has become one of the most extensively used insecticides for both crop protection and animal health applications. As with other classes of insecticides, resistance to neonicotinoids is a significant threat and has been identified in several pest species, including the brown planthopper,Nilaparvata lugens, a major rice pest in many parts of Asia. In this study, radioligand binding experiments have been conducted with whole-body membranes prepared from imidacloprid-susceptible and imidacloprid-resistant strains ofN. lugens. The results reveal a much higher level of [3H]imidacloprid-specific binding to the susceptible strain than to the resistant strain (16.7 ± 1.0 and 0.34 ± 0.21 fmol/mg of protein, respectively). With the aim of understanding the molecular basis of imidacloprid resistance, five nAChR subunits (Nlα1–Nlα4 and Nlβ1) have been cloned fromN. lugens.A comparison of nAChR subunit genes from imidacloprid-sensitive and imidacloprid-resistant populations has identified a single point mutation at a conserved position (Y151S) in two nAChR subunits, Nlα1 and Nlα3. A strong correlation between the frequency of the Y151S point mutation and the level of resistance to imidacloprid has been demonstrated by allele-specific PCR. By expression of hybrid nAChRs containingN. lugensα and rat β2 subunits, evidence was obtained that demonstrates that mutation Y151S is responsible for a substantial reduction in specific [3H]imidacloprid binding. This study provides direct evidence for the occurrence of target-site resistance to a neonicotinoid insecticide.
Structural basis for origin recognition complex 1 protein–silence information regulator 1 protein interaction in epigenetic silencing
Authors: Hsu Hao-Chi , Stillman Bruce , Xu Rui-Ming
Published: June 2005

The interaction between silence information regulator 1 protein (Sir1p) and origin recognition complex 1 protein (Orc1p), the largest subunit of the origin recognition complex, plays an important role in the establishment of transcriptional silencing at the cryptic mating-type gene loci in
Saccharomyces cerevisiae
. Sir1p binds the N-terminal region of Orc1p encompassing a Bromo-adjacent homology (BAH) domain found in various chromatin-associated proteins. To understand the molecular mechanism of Sir protein recruitment, we have determined a 2.5-Å cocrystal structure of the N-terminal domain of Orc1p in complex with the Orc1p-interacting domain of Sir1p. The structure reveals that Sir1p Orc1p-interacting domain has a bilobal structure: an α/β N-terminal lobe and a C-terminal lobe resembling the Tudor domain royal family fold. The N-terminal lobe of Sir1p binds in a shallow groove between a helical subdomain and the BAH domain of Orc1p. The structure provides a mechanistic understanding of Orc1p–Sir1p interaction specificity, as well as insights into protein–protein interactions involving BAH domains in general.
Interaction between genetic susceptibility and early-life environmental exposure determines tumor-suppressor-gene penetrance
Authors: Cook Jennifer D. , Davis Barbara J. , Cai Sheng-Li , Barrett J. Carl , Conti Claudio J. , Walker Cheryl Lyn
Published: June 2005

Gene–environment interactions are important determinants of cancer risk. Traditionally, gene–environment interactions are thought to contribute to tumor-suppressor-gene penetrance by facilitating or inhibiting the acquisition of additional somatic mutations required for tumorigenesis. Here, we demonstrate that a distinctive type of gene–environment interaction can occur during development to enhance the penetrance of a tumor-suppressor-gene defect in the adult. Using rats carrying a germ-line defect in the tuberous sclerosis complex 2 (
Tsc-2
) tumor-suppressor gene predisposed to uterine leiomyomas, we show that an early-life exposure to diethylstilbestrol during development of the uterus increased tumor-suppressor-gene penetrance from 65% to >90% and tumor multiplicity and size in genetically predisposed animals, but it failed to induce tumors in wild-type rats. This exposure was shown to impart a hormonal imprint on the developing uterine myometrium, causing an increase in expression of estrogen-responsive genes before the onset of tumors. Loss of function of the normal
Tsc-2
allele remained the rate-limiting event for tumorigenesis; however, tumors that developed in exposed animals displayed an enhanced proliferative response to steroid hormones relative to tumors that developed in unexposed animals. These data suggest that exposure to environmental factors during development can permanently reprogram normal physiological tissue responses and thus lead to increased tumor-suppressor-gene penetrance in genetically susceptible individuals.
Small-molecule inhibition of proteasome and aggresome function induces synergistic antitumor activity in multiple myeloma
Authors: Hideshima Teru , Bradner James E. , Wong Jason , Chauhan Dharminder , Richardson Paul , Schreiber Stuart L. , Anderson Kenneth C.
Published: June 2005

We have shown that the proteasome inhibitor bortezomib (formerly known as PS-341) triggers significant antitumor activity in multiple myeloma (MM) in both preclinical models and patients with relapsed refractory disease. Recent studies have shown that unfolded and misfolded ubiquitinated proteins are degraded not only by proteasomes, but also by aggresomes, dependent on histone deacetylase 6 (HDAC6) activity. We therefore hypothesized that inhibition of both mechanisms of protein catabolism could induce accumulation of ubiquitinated proteins followed by significant cell stress and cytotoxicity in MM cells. To prove this hypothesis, we used bortezomib and tubacin to inhibit the proteasome and HDAC6, respectively. Tubacin specifically triggers acetylation of α-tubulin as a result of HDAC6 inhibition in a dose- and time-dependent fashion. It induces cytotoxicity in MM cells at 72 h with an IC
50
of 5–20 μM, which is mediated by caspase-dependent apoptosis; no toxicity is observed in normal peripheral blood mononuclear cells. Tubacin inhibits the interaction of HDAC6 with dynein and induces marked accumulation of ubiquitinated proteins. It synergistically augments bortezomib-induced cytotoxicity by c-Jun NH
2
-terminal kinase/caspase activation. Importantly, this combination also induces significant cytotoxicity in plasma cells isolated from MM patient bone marrow. Finally, adherence of MM cells to bone marrow stromal cells confers growth and resistance to conventional treatments; in contrast, the combination of tubacin and bortezomib triggers toxicity even in adherent MM cells. Our studies therefore demonstrate that tubacin combined with bortezomib mediates significant anti-MM activity, providing the framework for clinical evaluation of combined therapy to improve patient outcome in MM.
The NF1 tumor suppressor critically regulates TSC2 and mTOR
Authors: Johannessen Cory M. , Reczek Elizabeth E. , James Marianne F. , Brems Hilde , Legius Eric , Cichowski Karen
Published: June 2005

Loss-of-function mutations in the
NF1
tumor suppressor gene underlie the familial cancer syndrome neurofibromatosis type I (NF1). The
NF1
-encoded protein, neurofibromin, functions as a Ras-GTPase activating protein (RasGAP). Accordingly, deregulation of Ras is thought to contribute to NF1 development. However, the critical effector pathways involved in disease pathogenesis are still unknown. We show here that the mTOR pathway is tightly regulated by neurofibromin. mTOR is constitutively activated in both
NF1
-deficient primary cells and human tumors in the absence of growth factors. This aberrant activation depends on Ras and PI3 kinase, and is mediated by the phosphorylation and inactivation of the
TSC2
-encoded protein tuberin by AKT. Importantly, tumor cell lines derived from NF1 patients, and a genetically engineered cell system that requires
Nf1
-deficiency for transformation, are highly sensitive to the mTOR inhibitor rapamycin. Furthermore, while we show that the activation of endogenous Ras leads to constitutive mTOR signaling in this disease state, we also demonstrate that in normal cells Ras is differentially required for mTOR signaling in response to various growth factors. Thus, these findings identify the NF1 tumor suppressor as an indispensable regulator of TSC2 and mTOR. Furthermore, our results also demonstrate that Ras plays a critical role in the activation of mTOR in both normal and tumorigenic settings. Finally, these data suggest that rapamycin, or its derivatives, may represent a viable therapy for NF1.
Golgi targeting of human guanylate-binding protein-1 requires nucleotide binding, isoprenylation, and an IFN-γ-inducible cofactor
Authors: Modiano Nir , Lu Yanping E. , Cresswell Peter
Published: June 2005

Human guanylate-binding protein-1 (hGBP-1) is a large GTPase, similar in structure to the dynamins. Like many smaller GTPases of the Ras/Rab family, it is farnesylated, suggesting it may dock into membranes and perhaps play a role in intracellular trafficking. To date, however, hGBP-1 has never been associated with a specific intracellular compartment. Here we present evidence that hGBP-1 can associate with the Golgi apparatus. Redistribution from the cytosol to the Golgi was observed by immunofluorescence and subcellular fractionation after aluminum fluoride treatment, suggesting that it occurs when hGBP-1 is in its GTP-bound state. Relocalization was blocked by a farnesyl transferase inhibitor. The C589S mutant of hGBP-1, which cannot be farnesylated, and the previously uncharacterized R48P mutant, which cannot bind GTP, both failed to localize to the Golgi. These two mutants had a dominant-negative effect, preventing endogenous wild-type hGBP-1 from efficiently redistributing after aluminum fluoride treatment. Furthermore, hGBP-1 requires another IFN-γ-induced factor to be targeted to the Golgi, because constitutively expressed hGBP-1 remained cytosolic in cells treated with aluminum fluoride unless the cells were preincubated with IFN-γ. Finally, two nonhydrolyzing mutants of hGBP-1, corresponding to active mutants of Ras family proteins, failed to constitutively associate with the Golgi; we propose three possible explanations for this surprising result.
How human neuroblastoma cells make morphine
Authors: Boettcher Chotima , Fellermeier Monika , Boettcher Christian , Dräger Birgit , Zenk Meinhart H.
Published: June 2005

Recently, our laboratory demonstrated that human neuroblastoma cells (SH-SY5Y) are capable of synthesizing morphine, the major active metabolite of opium poppy. Now our experiments are further substantiated by extending the biochemical studies to the entire morphine pathway in this human cell line.
l
-[1,2,3-
13
C
3
]- and [
ring
-2′,5′,6′-
2
H
3
]dopa showed high isotopic enrichment and incorporation in both the isoquinoline and the benzyl moiety of the endogenous morphine. [2,2-
2
H
2
]Dopamine, however, was exclusively incorporated only into the isoquinoline moiety. Neither the trioxygenated (
R,S
)-[1,3-
13
C
2
]norcoclaurine, the precursor of morphine in the poppy plant, nor (
R
)-[1,3,4-
2
H
3
]norlaudanosoline showed incorporation into endogenous morphine. However, (
S
)-[1,3,4-
2
H
3
]norlaudanosoline furnished a good isotopic enrichment and the loss of a single deuterium atom at the C-9 position of the morphine molecule, indicating that the change of configuration from (
S
)- to (
R
)-reticuline occurs via the intermediacy of 1,2-dehydroreticuline. Additional feeding experiments with potential morphinan precursors demonstrated substantial incorporation of [7-
2
H]salutaridinol, but not 7-[7-
2
H]episalutaridinol, and [7-
2
H,
N
-C
2
H
3
]oripavine, and [6-
2
H]codeine into morphine. Human morphine biosynthesis involves at least 19 chemical steps. For the most part, it is a reflection of the biosynthesis in opium poppy; however, there is a fundamental difference in the formation of the key intermediate (
S
)-reticuline: it proceeds via the tetraoxygenated initial isoquinoline alkaloid (
S
)-norlaudanosoline, whereas the plant morphine biosynthesis proceeds via the trioxygenated (
S
)-norcoclaurine. Following the plant biosynthetic pathway, (
S
)-reticuline undergoes a change of configuration at C-1 during its transformation to salutaridinol and thebaine. From thebaine, there is a bifurcate pathway leading to morphine proceeding via codeine or oripavine, in both plants and mammals.
Specificity of cell–cell adhesion by classical cadherins: Critical role for low-affinity dimerization through β-strand swapping
Authors: Chen Chien Peter , Posy Shoshana , Ben-Shaul Avinoam , Shapiro Lawrence , Honig Barry H.
Published: June 2005

Cadherins constitute a family of cell-surface proteins that mediate intercellular adhesion through the association of protomers presented from juxtaposed cells. Differential cadherin expression leads to highly specific intercellular interactions
in vivo
. This cell–cell specificity is difficult to understand at the molecular level because individual cadherins within a given subfamily are highly similar to each other both in sequence and structure, and they dimerize with remarkably low binding affinities. Here, we provide a molecular model that accounts for these apparently contradictory observations. The model is based in part on the fact that cadherins bind to one another by “swapping” the N-terminal β-strands of their adhesive domains. An inherent feature of strand swapping (or, more generally, the domain swapping phenomenon) is that “closed” monomeric conformations act as competitive inhibitors of dimer formation, thus lowering affinities even when the dimer interface has the characteristics of high-affinity complexes. The model describes quantitatively how small affinity differences between low-affinity cadherin dimers are amplified by multiple cadherin interactions to establish large specificity effects at the cellular level. It is shown that cellular specificity would not be observed if cadherins bound with high affinities, thus emphasizing the crucial role of strand swapping in cell–cell adhesion. Numerical estimates demonstrate that the strength of cellular adhesion is extremely sensitive to the concentration of cadherins expressed at the cell surface. We suggest that the domain swapping mechanism is used by a variety of cell-adhesion proteins and that related mechanisms to control affinity and specificity are exploited in other systems.
Activator of G protein signaling 3 regulates opiate activation of protein kinase A signaling and relapse of heroin-seeking behavior
Authors: Yao Lina , McFarland Krista , Fan Peidong , Jiang Zhan , Inoue Yuichiro , Diamond Ivan
Published: June 2005

The nucleus accumbens (NAc) is central to heroin addiction. Activation of opiate receptors in the NAc dissociates G
i/o
into α and βγ subunits. Gα
i
inhibits cAMP production, but βγ regulates several molecular pathways, including protein kinase A (PKA). We show in NAc/striatal neurons that opiates paradoxically activate PKA signaling by means of βγ dimers. Activation requires Gα
i3
and an activator of G protein signaling 3 (AGS3). AGS3 competes with βγ for binding to Gα
i3
-GDP and enhances the action of unbound βγ. AGS3 and Gα
i3
knockdown prevents opiate activation of PKA signaling. In rats self-administering heroin, AGS3 antisense in the NAc core, but not shell, eliminates reinstatement of heroin-seeking behavior, a model of human relapse. Thus, Gα
i3
/βγ/AGS3 appears to mediate μ opiate receptor activation of PKA signaling as well as heroin-seeking behavior.
Anthropoid primates from the Oligocene of Pakistan (Bugti Hills): Data on early anthropoid evolution and biogeography
Authors: Marivaux Laurent , Antoine Pierre-Olivier , Baqri Syed Rafiqul Hassan , Benammi Mouloud , Chaimanee Yaowalak , Crochet Jean-Yves , de Franceschi Dario , Iqbal Nayyer , Jaeger Jean-Jacques , Métais Grégoire , Roohi Ghazala , Welcomme Jean-Loup
Published: June 2005

Asian tarsiid and sivaladapid primates maintained relictual distributions in southern Asia long after the extirpation of their close Holarctic relatives near the Eocene–Oligocene boundary. We report here the discovery of amphipithecid and eosimiid primates from Oligocene coastal deposits in Pakistan that demonstrate that stem anthropoids also survived in southern Asia beyond the climatic deterioration that characterized the Eocene–Oligocene transition. These fossils provide data on temporal and paleobiogeographic aspects of early anthropoid evolution and significantly expand the record of stem anthropoid evolution in the Paleogene of South Asia.
Myocardin-related transcription factor B is required in cardiac neural crest for smooth muscle differentiation and cardiovascular development
Authors: Li Jian , Zhu Xiaohong , Chen Mary , Cheng Lan , Zhou Deying , Lu Min Min , Du Kevin , Epstein Jonathan A. , Parmacek Michael S.
Published: June 2005

Members of the myocardin-related family of transcription factors play critical roles in regulating vascular smooth muscle and cardiac differentiation. To examine the function of myocardin-related transcription factor (MRTF)-B, mice were generated from ES cells harboring a conditional insertional mutation, or gene trap, of the
MRTF-B
gene. Expression of the
MRTF-B
mutant allele results in a fusion protein consisting of the N terminus of MRTF-B fused to β-galactosidase, which is functionally null. Homozygous MRTF-B gene trap mice (
MRTF-B
–/–
) die between embryonic day (E)17.5 and postnatal day 1 from cardiac outflow tract defects. MRTF-B is expressed in the premigratory neural crest, in rhombomeres 3 and 5, and in the neural crest-derived mesenchyme surrounding the aortic arch arteries. Consistent with the pattern of expression, E10.5 and E11.5
MRTF-B
–/–
mutants exhibit deformation of aortic arch arteries 3, 4, and 6 and severe attenuation of smooth muscle cell differentiation in the arch arteries and the aorticopulmonary septum, despite normal migration and initial patterning of cardiac neural crest cells. Remarkably, the observed pathology was rescued and viable mice generated by intercrossing MRTF-B mutants with mice expressing Cre recombinase under the transcriptional control of the neural crest-restricted Wnt-1 promoter, which results in restoration of normal MRTF-B expression in the neural crest. Taken together, these studies reveal that MRTF-B plays a critical role in regulating differentiation of cardiac neural crest cells into smooth muscle and demonstrate that neural crest-derived smooth muscle differentiation is specifically required for normal cardiovascular morphogenesis.
Prevention of coprophagy in the rat. A new method
Authors: Armstrong B. K. , Softly A.
Published: June 2005

1. Coprophagy in rats was prevented by the use of a leather jacket and large-mesh, screen floor cages. 2. This caused considerable depression of growth of prevented rats compared with non-prevented rats on the same diet.
A study of the protein requirements of the mature breeding ewe
Authors: Robinson J. J. , Forbes T. J.
Published: June 2005

1. An experiment was carried out in which protein utilization in the pregnant ewe was studied using the nitrogen balance technique.

2. Eight diets supplying four different intakes of crude protein and two different intakes of energy were each offered to eight individually penned ewes.

3. The mean crude protein intakes per day were 7·2, 5·5, 4·1 and 3·0 g/kg W0·73 (where W = body-weight) and the metabolizable energy intakes 134 and 113 kcal/kg W0·73.

4. N balances were carried out at 10–12, 14–16 and 18–20 weeks of gestation on five ewes from each treatment.

5. The apparent digestibility of both dry matter and crude protein decreased with decreasing protein intake. With the high energy intake, the apparent dry-matter digestibility was increased and the apparent digestibility of crude protein decreased. Stage of gestation had no significant effect on the apparent digestibility of either of these constituents.

6. N retention was not affected by the number of foetuses carried. With the higher energy intake and the higher protein intakes, the absolute retention of N was significantly increased at all stages of gestation. N retention increased with advancing pregnancy; the retentions at 10–12, 14–16 and 18–20 weeks of gestation being 0·086, 0·114 and 0·163 g/kg W0·73 per day respectively.

7. The efficiency of utilization of apparently digested N was calculated from the regression of retained N as a percentage of apparently digested N against apparently digested N.

8. The daily intakes of apparently digested N required for maximum efficiency were 0·551 and 0·620 g/kg W0·73 on the high and low energy intakes respectively. The daily intake for maximum efficiency decreased with advancing pregnancy, the values being 0·623, 0·587 and 0·567 g/kg W0·73 for the 10–12, 14–16 and 18–20 weeks of gestation respectively.

9. The levels of N retained at maximum efficiency were 0·235 and 0·202 g/kg W0·73 per day for the high and low energy intakes respectively. The levels of N retained increased during pregnancy from 0·170 g/kg W0·73 per day at 10–12 weeks to 0·286 g/kg W0·73 at 18–20 weeks. The requirements for zero N balance were 0·072 and 0·153 g apparently digested N/kg W0·73 per day for the high and low energy intakes respectively. The requirement for zero N balance decreased from 0·176 g/kg W0·73 per day at 10–12 weeks to 0·071 g/kg W0·73 at 18–20 weeks.

10. The results are discussed in relation to other research findings and current recommendations.
Physical growth and neurointegrative performance of survivors of protein–energy malnutrition
Authors: Pereira Sheila M. , Sundararaj Regina , Begum Almas
Published: June 2005

1.The anthropometric measurements and neurointegrative performance of seventy-nine children aged 6–12 years who had survived kwashiorkor in early childhood were compared to those of 142 children who served as controls.

2. For the boys the differences in height and weight between those who had survived protein-energy malnutrition (PEM) and the controls were significant (P< 0.01).

3. For the girls the differences in height and weight between those who had survived PEM and the controls were not significant.

4. In the tests chosen, the performances of the survivors of PEM was significantly poorer than that of the controls.

5. There was no improvement in the performance when thirteen survivors were reassessed at 10 years of age.

6. There was a significant difference in scholastic performance between the survivors of PEM and the normal controls. The scholastic performance of the siblings of PEM survivors was also significantly better than that of the PEM survivors.

7. The dietary intakes at the time of reassessment were unsatisfactory in 25% of the survivors, but did not relate to their scholastic abilities.
The measurement of exchangeable pools of zinc using the stable isotope70Zn
Authors: Fairweather-Tait Susan J. , Jackson Malcolm J. , Fox Thomas E. , Wharf S. Gabrielle , Eagles John , Croghan Peter C.
Published: June 2005

The present study was designed to assess the feasibility of using small doses of a stable isotope of Zn to follow plasma kinetics over a 10 d period and, hence, make deductions about Zn turnover and body pool sizes. At the beginning of the 10 d metabolic balance, two adults, consuming their habitual diet, were given an intravenous injection of70Zn. There was a fourfold difference in the administered dose between the two subjects (0·445 and 2·078 mg). Blood samples were taken at regular intervals and plasma enrichment with70Zn measured by thermal ionization mass spectrometry. Urine and faeces were collected and analysed for Zn and70Zn. Kinetic analysis of the plasma70Zn decay by several different methods was undertaken. It was apparent from both deconvolution analysis of the short-term (0–90 min) decay data and four-compartment modelling of the longer-term (0–24 h) data that isotopic Zn very rapidly equilibrates with the plasma Zn and with a rapidly exchanging non-plasma pool, probably located within the liver. This latter pool appears to contain less than 10 mg Zn and the peak of isotope enrichment occurs at about 20 min post injection. The later decay of plasma Zn enrichment appears to be dictated by exchange with a much larger pool of approximate size 350 mg.
Plasma lipids and large bowel volatile fatty acids in pigs fed on white rice, brown rice and rice bran
Authors: Marsono Yustinus , Illman Richard J. , Clarke Julie M. , Trimble Rodney P. , Topping David L.
Published: June 2005

Adult male pigs were fed on a diet containing (% of energy) fat 25 starch 55 from white rice and providing 20 g fibre/pig per d (diet WR). In two other groups rice bran was added to the diet to provide 43 g fibre/d. One group received the diet unmodified (diet RB), but in another (diet RO) heat-stabilized unrefined rice oil replaced the palm oil. In a further group brown rice replaced white rice and provided 37 g fibre/pig per d (diet BR). Plasma cholesterol concentrations were similar with diets WR, RB and BR. With diet RO the concentration was significantly lower than with diets WR and BR but was not different from diet RB. Plasma high-density-lipoprotein-cholesterol and plasma triacylglycerols were unaffected by diet. In all groups, digesta mass rose from the caecum to the proximal colon but fell in the distal colon. Diet WR gave the lowest digesta mass while diet BR gave a significantly higher mass along the large bowel length. RB- and RO-fed pigs had equal masses of digesta which were intermediate between BR- and WR-fed pigs at all sampling sites. Pools of individual and total volatile fatty acids (VFA) in the proximal large bowel were unaffected by diet. Pools of total and individual VFA in the median and distal colon were lowest with diets WR and RB and significantly higher with diet BR. In these regions of the colon pools of acetate in RO-fed pigs did not differ from those in the BR-fed group but were higher than in other groups. However, pools of propionate and butyrate with the RO diet were significantly lower than with diet BR and the same as with diets WR and RB. Portal venous VFA concentrations were unaffected by diet. The higher large bowel digesta masses and VFA with diet BR may reflect the escape of starch from the smallintestine.
Parental death from cardiovascular disease and dietary habits in an elderly group
Authors: Ortega Rosa M. , Andres Pedro , Azuela Matilde , Encinas-Sotillos Alfonso , Gaspar Maria Jesus
Published: June 2005

The present study examines the influence of parental history of death from cardiovascular disease on dietary habits and nutritional status of a group of seventy-two Spanish elderly. Those with at least one parent who had died of cardiovascular disease (43·1% of the cases) had higher diastolic blood pressure (P< 0·05) and nutrient intakes less favourable from the cardiovascular risk point of view than those whose parents died of other causes. Descendants whose parents died of cardiovascular disease had higher total fat, animal fat, saturated fatty acids, myristic acid and palmitic acid intakes and a lower monounsaturated fatty acids: saturated fatty acids value than descendants of those who died from other causes (allP< 0·05).
Effect of driedBacillus subtilisculture on growth, body composition and hepatic lipogenic enzyme activity in female broiler chicks
Authors: Santoso U. , Tanaka K. , Ohtani S.
Published: June 2005

To investigate the effect of driedBacillus subtilisculture on growth, body composition and hepatic lipogenic enzyme activity, female broiler chicks were fed on either no additive (control) or driedB. subtills-culture-supplemented commercial diets (215 g crude protein/kg, 12.85 MJ metabolizable energy/kg) at 10 or 20 g/kg diet for 28 d from 14 to 42 d of age. Body weight, and moisture, fat, protein and ash contents of the body were not influenced by theB. subtilisculture. Feed efficiency. N utilization, the ratio of abdominal fat or liver to body weight, acetyl-coenzyme A carboxylase (EC6·4·1·2) activity, liver and serum cholesterol contents were significantly lower in treatment groups, while fatty acid synthetase activity and serum cholesterol concentration were not significantly different, compared with the control group. Liver triacylglycerol concentration was decreased in chicks given 20 g culture·kg diet, while serum and carcass triacylglycerol concentrations were significantly lower in treatment groups than in the control group. Serum phospholipid concentration was increased but carcass phospholipid concentration was decreased in chicks given 20 gB. subtilis/kg diet, while liver phospholipid concentration was not significantly influenced. The advantages of inclusion ofB. subtilisto the broiler diet included improved feed efficiency, less abdominal fat, reduced triacylglycerol concentrations in the liver, serum and carcass and reduced cholesterol concentrations in the liver and carcass.
Effects of feeding and short-term fasting on water and electrolyte turnover in female mink (Mustela vison)
Authors: Wamberg Søren , Tauson Anne-Helene , Elnif Jan
Published: June 2005

Daily (24 h) rates of water and electrolyte turnover were measured in a conventional balance study in ten adult female pastel mink (Mustela vison) given free access to a standard mink feed for a 1-week conditioning period, followed by a 4 d experimental period and a 2 d fasting period. Drinking water was available throughout. In addition, the completeness of urine collection and the fraction of urine collected with the faeces were determined using a new experimental technique based on 24 h recoveries of specific urinary markers such as tritiatedp-aminohippuric acid ([3H]PAH) or14C-1abelled inulin ([14C]IN) continuously delivered by small Alzet® osmotic pumps implanted intraperitoneally. During feeding the mean individual percentage recovery in urine of [3H]PAH released from tbe osmotic pumps ranged from 68 to 88% (median 78%). Tbe mean percentage of urinary [3H]PAH recovered from faecal collections was 6% (range 3–12%). In response to fasting the mean individual percentage recovery of [3H]PAH in urine ranged from 62 to 78% (median 68%). For urinary [14C]IN the mean percentage recoveries in fed and fasted animals were 79 and 63% respectively. Furthermore, during fasting, withdrawal of the supplies of dietary water caused a slight but insignificant (P = 0·17) increase in the daily intake of drinking water and, hence, the animals maintained their normal water balance by a dramatic reduction in urine excretion (P < 0·001). At the same time urinary solute excretion declined significantly (P < 0·001), due in part to the cessation of dietary electrolyte intake and in part to reduced formation of urea, whereas urinary osmolality decreased only moderately. The mean 24 h balances of Na, K, Ca, Mg, Cl and P were close to zero and only minor differences between the feeding and fasting periods were observed. When corrected for the measured inaccuracies in urine collection the balance data obtained in the present study represent useful reference standards for normally fed and fasted non-growing mink and, to some extent, useful guidelines for future studies in experimental animals.
Streptozotocin-induced diabetes lowers retinol-binding protein and transthyretin concentrations in rats
Authors: Tuitoek P. J. , Rittere S. J. , Smitha J. E. , Basu T. K.
Published: June 2005

Retinol-binding protein (RBP) and transthyretin (TTR) in the plasma, liver and kidney, retinol in plasma, and total vitamin A in the liver were measured in rats 6 weeks after diabetes mellitus had been induced by streptozotocin (STZ). The diabetic rats gained 83% less weight despite consuming 45% more feed than the non-diabetic controls. Plasma and kidney concentrations of RBP and TTR were significantly lower in diabetic than in the non-diabetic control rats. Unlike the retinol carrier proteins, plasma albumin concentrations remained unaffected. Plasma concentrations of retino1 were decreased while its hepatic levels increased in the diabeticanimals. The depressed circulatory levels of retinol may reflect an altered metabolism of its transport proteins
Influence of caecal microflora and of two dietary protein levels on the adaptation of the exocrine pancreas: comparative study in germ-free and conventional rats
Authors: Lhoste Evelyne F. , Catala Isabelle , Fiszlewicz Michèle , Gueugneau A. M. , Popot Fran¸oise , Vaissade Pierre , Corring Tristan , Szylit Odette
Published: June 2005

Dietary proteins are degraded by both endogenous enzymes and the caecal microflora. In conventional rats the enzyme content of the pancreas depends on the amount of dietary protein. The influence of the caecal microflora on this process is unknown. We report here the effect of the caecal microflora on pancreatic enzymes (proteases, amylase (EC3.2.1.l), lipase (EC3.1.1.3)) and on colonic metabolites (NH3, urea, short-chain fatty acids). Germ-free and conventional male Fischer rats were fed for 3 weeks with a diet containing 220 or 450 g protein/kg provided as a mixture of fish concentrate and soyabean isolate. The excretion of NH3, and the pH were specifically increased by the high-protein diet in the germ-free rats. The higher production of isobutyrate, valerate and isovalerate in conventional rats fed on the high-protein diet reflected a high bacterial proteolytic activity since these short-chain fatty acids are specific indicators of this activity. The microflora hydrolysed urea to NH3and maintained the pH at neutrality whatever the amount of protein in the diet since there were changes in germ-free rats but not in conventional ones. In germ-free rats, amylase, trypsin (EC3.4.21.4), elastase (EC3.4.21.36) and carboxypeptidase A (EC3.4.17.1) specific activities were significantly lower than in conventional rats. The adaptation of the pancreas to the 450 g protein/kg diet was not impaired by the bacterial status except for the specific activity of chymotrypsin (EC3.4.21.1) which was more increased by this diet in germ-free than in conventional rats. Moreover, the specific activity of lipase increased only in conventional rats fed on the 450g protein/kg diet. In conclusion, we observed a relationship between the enzyme content of the pancreas and the presence or absence of the caecal microflora suggesting that bacterial fermentation influences pancreatic function.
A novel acylglycerol kinase that produces lysophosphatidic acid modulates cross talk with EGFR in prostate cancer cells
Authors: Bektas Meryem , Payne Shawn G. , Liu Hong , Goparaju Sravan , Milstien Sheldon , Spiegel Sarah
Published: June 2005

The bioactive phospholipids, lysophosphatidic acid (LPA) and phosphatidic acid (PA), regulate pivotal processes related to the pathogenesis of cancer. Here, we report characterization of a novel lipid kinase, designated acylglycerol kinase (AGK), that phosphorylates monoacylglycerol and diacylglycerol to form LPA and PA, respectively. Confocal microscopy and subcellular fractionation suggest that AGK is localized to the mitochondria. AGK expression was up-regulated in prostate cancers compared with normal prostate tissues from the same patient. Expression of AGK in PC-3 prostate cancer cells markedly increased formation and secretion of LPA. This increase resulted in concomitant transactivation of the EGF receptor and sustained activation of extracellular signal related kinase (ERK) 1/2, culminating in enhanced cell proliferation. AGK expression also increased migratory responses. Conversely, down-regulating expression of endogenous AGK inhibited EGF- but not LPA-induced ERK1/2 activation and progression through the S phase of the cell cycle. Hence, AGK can amplify EGF signaling pathways and may play an important role in the pathophysiology of prostate cancer.
De novo formation of basal bodies in Naegleria gruberi
Authors: Kim Hong-Kyung , Kang Jeong-Gu , Yumura Shigehiko , Walsh Charles J. , Cho Jin Won , Lee JooHun
Published: June 2005

The de novo formation of basal bodies in Naegleria gruberi was preceded by the transient formation of a microtubule (MT)-nucleating complex containing γ-tubulin, pericentrin, and myosin II complex (GPM complex). The MT-nucleating activity of GPM complexes was maximal just before the formation of visible basal bodies and then rapidly decreased. The regulation of MT-nucleating activity of GPM complexes was accomplished by a transient phosphorylation of the complex. Inhibition of dephosphorylation after the formation of basal bodies resulted in the formation of multiple flagella. 2D-gel electrophoresis and Western blotting showed a parallel relationship between the MT-nucleating activity of GPM complexes and the presence of hyperphosphorylated γ-tubulin in the complexes. These data suggest that the nucleation of MTs by GPM complexes precedes the de novo formation of basal bodies and that the regulation of MT-nucleating activity of GPM complexes is essential to the regulation of basal body number.
Physiological regulation of yeast cell death in multicellular colonies is triggered by ammonia
Authors: Váchová Libuše , Palková Zdena
Published: June 2005

The existence of programmed cell death (PCD) in yeast and its significance to simple unicellular organisms is still questioned. However, such doubts usually do not reflect the fact that microorganisms in nature exist predominantly within structured, multicellular communities capable of differentiation, in which a profit of individual cells is subordinated to a profit of populations. In this study, we show that some PCD features naturally appear during the development of multicellular Saccharomyces cerevisiae colonies. An ammonia signal emitted by aging colonies triggers metabolic changes that localize yeast death only in the colony center. The remaining population can exploit the released nutrients and survives. In colonies defective in Sok2p transcription factor that are unable to produce ammonia (Váchová, L., F. Devaux, H. Kucerova, M. Ricicova, C. Jacq, and Z. Palková. 2004. J. Biol. Chem. 279:37973–37981), death is spread throughout the whole population, thus decreasing the lifetime of the colony. The absence of Mca1p metacaspase or Aif1p orthologue of mammalian apoptosis-inducing factor does not prevent regulated death in yeast colonies.
ADAR2-mediated editing of RNA substrates in the nucleolus is inhibited by C/D small nucleolar RNAs
Authors: Vitali Patrice , Basyuk Eugenia , Le Meur Elodie , Bertrand Edouard , Muscatelli Françoise , Cavaillé Jérôme , Huttenhofer Alexander
Published: June 2005

Posttranscriptional, site-specific adenosine to inosine (A-to-I) base conversions, designated as RNA editing, play significant roles in generating diversity of gene expression. However, little is known about how and in which cellular compartments RNA editing is controlled. Interestingly, the two enzymes that catalyze RNA editing, adenosine deaminases that act on RNA (ADAR) 1 and 2, have recently been demonstrated to dynamically associate with the nucleolus. Moreover, we have identified a brain-specific small RNA, termed MBII-52, which was predicted to function as a nucleolar C/D RNA, thereby targeting an A-to-I editing site (C-site) within the 5-HT2C serotonin receptor pre-mRNA for 2′-O-methylation. Through the subcellular targeting of minigenes that contain natural editing sites, we show that ADAR2- but not ADAR1-mediated RNA editing occurs in the nucleolus. We also demonstrate that MBII-52 forms a bona fide small nucleolar ribonucleoprotein particle that specifically decreases the efficiency of RNA editing by ADAR2 at the targeted C-site. Our data are consistent with a model in which C/D small nucleolar RNA might play a role in the regulation of RNA editing.
α-Syntrophin regulates ARMS localization at the neuromuscular junction and enhances EphA4 signaling in an ARMS-dependent manner
Authors: Luo Shuo , Chen Yu , Lai Kwok-On , Arévalo Juan Carlos , Froehner Stanley C. , Adams Marvin E. , Chao Moses V. , Ip Nancy Y.
Published: June 2005

EphA4 signaling has recently been implicated in the regulation of synapse formation and plasticity. In this study, we show that ankyrin repeat-rich membrane spanning (ARMS; also known as a kinase D–interacting substrate of 220 kD), a substrate for ephrin and neurotrophin receptors, was expressed in developing muscle and was concentrated at the neuromuscular junction (NMJ). Using yeast two-hybrid screening, we identified a PDZ (PSD-95, Dlg, ZO-1) domain protein, α-syntrophin, as an ARMS-interacting protein in muscle. Overexpression of α-syntrophin induced ARMS clustering in a PDZ domain–dependent manner. Coexpression of ARMS enhanced EphA4 signaling, which was further augmented by the presence of α-syntrophin. Moreover, the ephrin-A1–induced tyrosine phosphorylation of EphA4 was reduced in C2C12 myotubes after the blockade of ARMS and α-syntrophin expression by RNA interference. Finally, α-syntrophin–null mice exhibited a disrupted localization of ARMS and EphA4 at the NMJ and a reduced expression of ARMS in muscle. Altogether, our findings suggest that ARMS may play an important role in regulating postsynaptic signal transduction through the syntrophin-mediated localization of receptor tyrosine kinases such as EphA4.
SURFIN is a polymorphic antigen expressed on Plasmodium falciparum merozoites and infected erythrocytes
Authors: Winter Gerhard , Kawai Satoru , Haeggström Malin , Kaneko Osamu , von Euler Anne , Kawazu Shin-ichiro , Palm Daniel , Fernandez Victor , Wahlgren Mats
Published: June 2005

The surfaces of the infected erythrocyte (IE) and the merozoite, two developmental stages of malaria parasites, expose antigenic determinants to the host immune system. We report on surface-associated interspersed genes (surf genes), which encode a novel polymorphic protein family, SURFINs, present on both IEs and merozoites. A SURFIN expressed in 3D7 parasites, SURFIN4.2, was identified by mass spectrometric analysis of peptides cleaved off the surface of live IEs with trypsin. SURFINs are encoded by a family of 10 surf genes, including three predicted pseudogenes, located within or close to the subtelomeres of five of the chromosomes. SURFINs show structural and sequence similarities with exported surface-exposed proteins (PvSTP1, PkSICAvar, PvVIR, Pf332, and PfEMP1) of several Plasmodium species. SURFIN4.2 of a parasite other than 3D7 (FCR3S1.2) showed polymorphisms in the extracellular domain, suggesting sequence variability between genotypes. SURFIN4.2 not only was found cotransported with PfEMP1 and RIFIN to the IE surface, but also accumulated in the parasitophorous vacuole. In released merozoites, SURFIN4.2 was present in an amorphous cap at the parasite apex, where it may be involved in the invasion of erythrocytes. By exposing shared polymorphic antigens on IEs and merozoites, the parasite may coordinate the antigenic composition of these attachment surfaces during growth in the bloodstream.
Mimicry of a constitutively active pre–B cell receptor in acute lymphoblastic leukemia cells
Authors: Feldhahn Niklas , Klein Florian , Mooster Jana L. , Hadweh Paul , Sprangers Mieke , Wartenberg Maria , Bekhite Mohamed M. , Hofmann Wolf-Karsten , Herzog Sebastian , Jumaa Hassan , Rowley Janet D. , Müschen Markus
Published: June 2005

Pre–B cells undergo apoptosis unless they are rescued by pre–B cell receptor–dependent survival signals. We previously showed that the BCR-ABL1 kinase that is expressed in pre–B lymphoblastic leukemia bypasses selection for pre–B cell receptor–dependent survival signals. Investigating possible interference of BCR-ABL1 with pre–B cell receptor signaling, we found that neither SYK nor SLP65 can be phosphorylated in response to pre–B cell receptor engagement. Instead, Bruton's tyrosine kinase (BTK) is constitutively phosphorylated by BCR-ABL1. Activated BTK is essential for survival signals that otherwise would arise from the pre–B cell receptor, including activation of PLCγ1, autonomous Ca2+ signaling, STAT5-phosphorylation, and up-regulation of BCLXL. Inhibition of BTK activity specifically induces apoptosis in BCR-ABL1+ leukemia cells to a similar extent as inhibition of BCR-ABL1 kinase activity itself. However, BCR-ABL1 cannot directly bind to full-length BTK. Instead, BCR-ABL1 induces the expression of a truncated splice variant of BTK that acts as a linker between the two kinases. As opposed to full-length BTK, truncated BTK lacks kinase activity yet can bind to BCR-ABL1 through its SRC-homology domain 3. Acting as a linker, truncated BTK enables BCR-ABL1–dependent activation of full-length BTK, which initiates downstream survival signals and mimics a constitutively active pre–B cell receptor.
An essential role for SKAP-55 in LFA-1 clustering on T cells that cannot be substituted by SKAP-55R
Authors: Jo Eun-Kyeong , Wang Hongyan , Rudd Christopher E.
Published: June 2005

Lymphocyte function-associated antigen (LFA)-1 clustering, which is needed for high avidity binding to intercellular adhesion molecule (ICAM)-1 and -2, regulates T cell motility and T cell–antigen-presenting cell (APC) conjugation. In this study, down-regulation of SKAP-55 by small interfering RNAs (siRNAs) identified an essential role for this adaptor molecule in the T cell receptor (TCR)–mediated ”inside-out signaling” that is needed for LFA-1 clustering and T cell–APC conjugation. In contrast, down-regulation of SKAP-55 had no effect on TCR–CD3 clustering. Furthermore, the expression of the related protein SKAP-55R failed to compensate for the loss of SKAP-55 in LFA-1 clustering, indicating that SKAP-55 has a unique function that cannot be replaced by this closely related protein. Our findings therefore indicate that SKAP-55, unlike SKAP-55R, is specifically tailored as an essential component of the inside-out signaling events that couple the TCR to LFA-1 clustering and T cell–APC conjugation.
Live imaging of effector cell trafficking and autoantigen recognition within the unfolding autoimmune encephalomyelitis lesion
Authors: Kawakami Naoto , Nägerl U. Valentin , Odoardi Francesca , Bonhoeffer Tobias , Wekerle Hartmut , Flügel Alexander
Published: June 2005

We tracked pathogenic myelin basic protein-specific CD4+ effector T cells in early central nervous system (CNS) lesions of experimental autoimmune encephalomyelitis (EAE) by combining two-photon imaging and fluorescence video microscopy. We made two key observations: (a) the majority of the cells (65%) moved fast (maximal speed 25 μm/min) and apparently nondirected through the compact tissue; and (b) a second group of effector T cells (35%) appeared tethered to a fixed point. Polarization of T cell receptor and adhesion molecules (lymphocyte function-associated antigen 1) towards this fixed point suggests the formation of immune synapses. Nonpathogenic, ovalbumin-specific T cells were not tethered in the CNS and did not form synapse-like contacts, but moved through the tissue. After intrathecal injection of antigen, 40% of ovalbumin-specific T cells became tethered. Conversely, injection of anti–major histocompatibility complex class II antibodies profoundly reduced the number of stationary pathogenic T cells within the CNS (to 15%). We propose that rapid penetration of the CNS parenchyma by numerous autoimmune effector T cells along with multiple autoantigen-presentation events are responsible for the fulminate development of clinical EAE.