bluuebunny/crossref_metadata_2025 huggingface dataset:
Selective modification of alternative splicing by indole derivatives that target serine-arginine-rich protein splicing factors
Authors: Soret Johann , Bakkour Nadia , Maire Sophie , Durand Sébastien , Zekri Latifa , Gabut Mathieu , Fic Weronika , Divita Gilles , Rivalle Christian , Dauzonne Daniel , Nguyen Chi Hung , Jeanteur Philippe , Tazi Jamal
Published: June 2005

The prevalence of alternative splicing as a target for alterations leading to human genetic disorders makes it highly relevant for therapy. Here we have usedin vitrosplicing reactions with different splicing reporter constructs to screen 4,000 chemical compounds for their ability to selectively inhibit spliceosome assembly and splicing. We discovered indole derivatives as potent inhibitors of the splicing reaction. Importantly, compounds of this family specifically inhibit exonic splicing enhancer (ESE)-dependent splicing, because they interact directly and selectively with members of the serine-arginine-rich protein family. Treatment of cells expressing reporter constructs with ESE sequences demonstrated that selected indole derivatives mediate inhibition of ESE usagein vivoand prevent early splicing events required for HIV replication. This discovery opens the exciting possibility of a causal pharmacological treatment of aberrant splicing in human genetic disorders and development of new antiviral therapeutic approaches.
Variation in DISC1 affects hippocampal structure and function and increases risk for schizophrenia
Authors: Callicott Joseph H. , Straub Richard E. , Pezawas Lukas , Egan Michael F. , Mattay Venkata S. , Hariri Ahmad R. , Verchinski Beth A. , Meyer-Lindenberg Andreas , Balkissoon Rishi , Kolachana Bhaskar , Goldberg Terry E. , Weinberger Daniel R.
Published: June 2005

Disrupted-in-schizophrenia 1 (DISC1) is a promising schizophrenia candidate gene expressed predominantly within the hippocampus. We typed 12 single-nucleotide polymorphisms (SNPs) that covered the DISC1 gene. A three-SNP haplotype [hCV219779 (C)-rs821597 (G)-rs821616 (A)] spanning 83 kb of the gene was associated with schizophrenia in a family-based sample (
P
= 0.002). A common nonconservative SNP (Ser704Cys) (rs821616) within this haplotype was associated with schizophrenia (
P
= 0.004). Based on primary expression of DISC1 in hippocampus, we hypothesized that allelic variation at Ser704Cys would have a measurable impact on hippocampal structure and function as assayed via specific hippocampus-related intermediate phenotypes. In addition to overtransmission in schizophrenia, the Ser allele was associated with altered hippocampal structure and function in healthy subjects, including reduced hippocampal gray matter volume and altered engagement of the hippocampus during several cognitive tasks assayed with functional magnetic resonance imaging. These convergent data suggest that allelic variation within DISC1, either at Ser704Cys or haplotypes monitored by it, increases the risk for schizophrenia and that the mechanism of this effect involves structural and functional alterations in the hippocampal formation.
UV irradiation stimulates histone acetylation and chromatin remodeling at a repressed yeast locus
Authors: Yu Yachuan , Teng Yumin , Liu Hairong , Reed Simon H. , Waters Raymond
Published: June 2005

Chromatin immunoprecipitation with anti-acetyl histone H3 (K9 and K14) and anti-acetyl histone H4 (K5, K8, K12, and K16) antibodies shows that Lys-9 and/or Lys-14 of histone H3, but not the relevant sites of histone H4 in nucleosomes at the repressed
MFA2
promoter, are hyperacetylated after UV irradiation. This level of histone hyperacetylation diminishes gradually as repair proceeds. Accompanying this, chromatin in the promoter becomes more accessible to restriction enzymes after UV irradiation and returns to the pre-UV state gradually. UV-related histone hyperacetylation and chromatin remodeling in the
MFA2
promoter depend on Gcn5p and partially on Swi2p, respectively. Deletion of
GCN5
, but not of
SWI2
, impairs repair of DNA damage in the
MFA2
promoter. The post-UV histone modifications and chromatin remodeling at the repressed
MFA2
promoter do not activate
MFA2
transcriptionally, nor do they require damage recognition by Rad4p or Rad14p. Furthermore, we show that UV irradiation triggers genome-wide histone hyperacetylation at both histone H3 and H4. These experiments indicate that chromatin at a yeast repressed locus undergoes active change after UV radiation treatment and that failure to achieve histone H3 hyperacetylation impairs the repair of DNA damage.
Different mutation signatures in DNA polymerase η- and MSH6-deficient mice suggest separate roles in antibody diversification
Authors: Martomo Stella A. , Yang William W. , Wersto Robert P. , Ohkumo Tsuyoshi , Kondo Yuji , Yokoi Masayuki , Masutani Chikahide , Hanaoka Fumio , Gearhart Patricia J.
Published: June 2005

Hypermutation in immunoglobulin genes produces a high frequency of substitutions of all four bases, which are likely generated by low-fidelity DNA polymerases. Indeed, humans deficient for DNA polymerase (pol) η have decreased substitutions of A·T base pairs in variable and switch regions. To study the role of pol η in a genetically tractable system, we created mice lacking pol η. B cells from
Polh
-/-
mice produced normal amounts of IgG, indicating that pol η does not affect class switch recombination. Similar to their human counterparts, variable and switch regions from
Polh
-/-
mice had fewer substitutions of A·T base pairs and correspondingly more mutations of C·G base pairs, which firmly establishes a central role for pol η in hypermutation. Notably, the location and types of substitutions differ markedly from those in
Msh6
-/-
clones, which also have fewer A·T mutations. The data suggest that pol η preferentially synthesizes a repair patch on the nontranscribed strand, whereas MSH6 functions to generate the patch.
VirulentCoxiella burnetiidoes not activate human dendritic cells: Role of lipopolysaccharide as a shielding molecule
Authors: Shannon Jeffrey G. , Howe Dale , Heinzen Robert A.
Published: June 2005

Coxiella burnetiiis an obligate intracellular bacterium and the etiological agent of the zoonotic disease Q fever. Acute human Q fever is characterized by flu-like symptoms that, in some cases, can result in a persistent infection that may reactivate months or years after initial exposure. Mechanisms by which this obligate parasite evades clearance by the host immune response during persistent infection are unknown. Here, we characterized the interaction ofC. burnetiiwith dendritic cells (DC), critical components of both innate and adaptive immunity. Human DC were infected with two isogenicC. burnetiistrains that differ in LPS length. Infection by the Nine Mile phase I (NMI) strain, which is fully virulent and produces full-length LPS, did not result in DC maturation. In contrast, infection by the avirulent Nine Mile phase II strain, producing a severely truncated LPS, resulted in toll-like receptor 4-independent DC maturation and ≈10-fold more IL-12 and TNF production. NMI did not actively inhibit DC maturation as NMI-infected DC subsequently matured if treated withEscherichia coliLPS or Nine Mile phase II. Furthermore, removal of LPS from NMI dramatically increased its ability to stimulate DC. We propose a model whereby LPS of virulentC. burnetiimasks toll-like receptor ligands from innate immune recognition by DC, thereby allowing replication without significant maturation or inflammatory cytokine production. This immune evasion strategy may allowC. burnetiito persist in an immunocompetent host.
Cytoplasmic LEK1 is a regulator of microtubule function through its interaction with the LIS1 pathway
Authors: Soukoulis Victor , Reddy Samyukta , Pooley Ryan D. , Feng Yuanyi , Walsh Christopher A. , Bader David M.
Published: June 2005

LIS1 and nuclear distribution gene E (NudE) are partner proteins in a conserved pathway regulating the function of dynein and microtubules. Here, we present data that cytoplasmic LEK1 (cytLEK1), a large protein containing a spectrin repeat and multiple leucine zippers, is a component of this pathway through its direct interaction with NudE, as determined by a yeast two-hybrid screen. We identified the binding domains in each molecule, and coimmunoprecipitation and colocalization studies confirmed the specificity of the interaction between cytLEK1 and NudE. Confocal deconvolution analysis revealed that cytLEK1 exhibits colocalization with endogenous NudE and with the known NudE binding partners, LIS1 and dynein. By localizing the NudE-binding domain of cytLEK1 to a small domain within the molecule, we were able to disrupt cytLEK1 function by using a dominant negative approach in addition to LEK1 knockdown and, thus, examine the role of the cytLEK1–NudE interaction in cells. Consistent with a defect in the LIS1 pathway, disruption of cytLEK1 function resulted in alteration of microtubule organization and cellular shape. The microtubule network of cells became tightly focused around the nucleus and resulted in a rounded cell shape. Additionally, cells exhibited a severe inability to repolymerize their microtubule networks after nocodazole challenge. Taken together, our studies revealed that cytLEK1 is essential for cellular functions regulated by the LIS1 pathway.
Gene transfer to human joints: Progress toward a gene therapy of arthritis
Authors: Evans Christopher H. , Robbins Paul D. , Ghivizzani Steven C. , Wasko Mary Chester , Tomaino Matthew M. , Kang Richard , Muzzonigro Thomas A. , Vogt Molly , Elder Elaine M. , Whiteside Theresa L. , Watkins Simon C. , Herndon James H.
Published: June 2005

This article describes the clinical application of gene therapy to a nonlethal disease, rheumatoid arthritis (RA). Intraarticular transfer of IL-1 receptor antagonist (IL-1Ra) cDNA reduces disease in animal models of RA. Whether this procedure is safe and feasible in humans was addressed in a phase I clinical study involving nine postmenopausal women with advanced RA who required unilateral sialastic implant arthroplasty of the 2nd-5th metacarpophalangeal (MCP) joints. Cultures of autologous synovial fibroblasts were established and divided into two. One was transduced with a retrovirus carrying IL-1Ra cDNA; the other provided untransduced, control cells. In a dose escalation, double-blinded fashion, two MCP joints were injected with transduced cells, and two MCP joints received control cells. One week later, injected joints were resected and examined for evidence of successful gene transfer and expression by using RT-PCR,ex vivoproduction of IL-1Ra,in situhybridization, and immunohistochemistry. All subjects tolerated the protocol well, without adverse events. Unlike control joints, those receiving transduced cells gave positive RT-PCR signals. Synovia that were recovered from the MCP joints of intermediate and high dose subjects produced elevated amounts of IL-1Ra (P= 0.01). Clusters of cells expressing high levels of IL-1Ra were present on synovia of transduced joints. No adverse events occurred. Thus, it is possible to transfer a potentially therapeutic gene safely to human rheumatoid joints and to obtain intraarticular, transgene expression. This conclusion justifies additional efficacy studies and encourages further development of genetic approaches to the treatment of arthritis and related disorders.
Engineered single-chain dimeric streptavidins with an unexpected strong preference for biotin-4-fluorescein
Authors: Aslan Filiz M. , Yu Yong , Mohr Scott C. , Cantor Charles R.
Published: June 2005

Streptavidin, a homotetrameric protein with extremely tight biotin binding (
K
d
≤ 10
-14
M), has been widely used as an affinity reagent. Its utility would be increased by engineering single-chain mutants with a wide spectrum of affinities, more suitable for phage-display and chip technologies. By a circular permutation procedure, we converted streptavidin to a single-chain dimer (SCD) with two biotin-binding sites and introduced random mutations by error-prone PCR. Clones from a phagemid library, expressed as gene-3 fusion proteins on M13 bacteriophage, were panned with biotinylated beads, and SCD genes from affinity-enriched phage were subcloned to produce soluble proteins. Purification of products from the original gene and two mutants by FPLC and analysis by MALDI-TOF MS showed they exist in both dimeric (single-chain) and tetrameric (two-chain) forms, which were further characterized for their binding affinity to biotin-4-fluorescein (B4F) by fluorescence polarization and intensity measurements.
K
d
′ values for B4F ranged from ≈10
-11
to 10
-10
M, although
K
d
values for biotin ranged from 10
-6
to 10
-5
M. These results point to the possibility of combining an SCD streptavidin mutant with B4F derivatives to create a fluorescence-tagged affinity system with tight but still-reversible interaction that could be used sequentially with ordinary streptavidin–biotin for composite separation or analysis steps.
Detection of glutamate release from neurons by genetically encoded surface-displayed FRET nanosensors
Authors: Okumoto Sakiko , Looger Loren L. , Micheva Kristina D. , Reimer Richard J. , Smith Stephen J , Frommer Wolf B.
Published: June 2005

Glutamate is the predominant excitatory neurotransmitter in the mammalian brain. Once released, its rapid removal from the synaptic cleft is critical for preventing excitotoxicity and spillover to neighboring synapses. Despite consensus on the role of glutamate in normal and disease physiology, technical issues limit our understanding of its metabolism in intact cells. To monitor glutamate levels inside and at the surface of living cells, genetically encoded nanosensors were developed. The fluorescent indicator protein for glutamate (FLIPE) consists of the glutamate/aspartate binding protein ybeJ fromEscherichia colifused to two variants of the green fluorescent protein. Three sensors with lower affinities for glutamate were created by mutation of residues peristeric to the ybeJ binding pocket. In the presence of ligands, FLIPEs show a concentration-dependent decrease in FRET efficiency. When expressed on the surface of rat hippocampal neurons or PC12 cells, the sensors respond to extracellular glutamate with a reversible concentration-dependent decrease in FRET efficiency. Depolarization of neurons leads to a reduction in FRET efficiency corresponding to 300 nM glutamate at the cell surface. No change in FRET was observed when cells expressing sensors in the cytosol were superfused with up to 20 mM glutamate, consistent with a minimal contribution of glutamate uptake to cytosolic glutamate levels. The results demonstrate that FLIPE sensors can be used for real-time monitoring of glutamate metabolism in living cells, in tissues, or in intact organisms, providing tools for studying metabolism or for drug discovery.
A general method for greatly improving the affinity of antibodies by using combinatorial libraries
Authors: Rajpal Arvind , Beyaz Nurten , Haber Lauric , Cappuccilli Guido , Yee Helena , Bhatt Ramesh R. , Takeuchi Toshihiko , Lerner Richard A. , Crea Roberto
Published: June 2005

Look-through mutagenesis (LTM) is a multidimensional mutagenesis method that simultaneously assesses and optimizes combinatorial mutations of selected amino acids. The process focuses on a precise distribution within one or more complementarity determining region (CDR) domains and explores the synergistic contribution of amino acid side-chain chemistry. LTM was applied to an anti-TNF-α antibody, D2E7, which is a challenging test case, because D2E7 was highly optimized (Kd= 1 nM) by others. We selected and incorporated nine amino acids, representative of the major chemical functionalities, individually at every position in each CDR and across all six CDRs (57 aa). Synthetic oligonucleotides, each introducing one amino acid mutation throughout the six CDRs, were pooled to generate segregated libraries containing single mutations in one, two, and/or three CDRs for each VHand VLdomain. Corresponding antibody libraries were displayed on the cell surface of yeast. After positive binding selection, 38 substitutions in 21 CDR positions were identified that resulted in higher affinity binding to TNF-α. These beneficial mutations in both VHand VLwere represented in two combinatorial beneficial mutagenesis libraries and selected by FACS to produce a convergence of variants that exhibit between 500- and 870-fold higher affinities. Importantly, these enhanced affinities translate to a 15- to 30-fold improvement inin vitroTNF-α neutralization in an L929 bioassay. Thus, this LTM/combinatorial beneficial mutagenesis strategy generates a comprehensive energetic map of the antibody-binding site in a facile and rapid manner and should be broadly applicable to the affinity maturation of antibodies and other proteins.
Disruption of the mouse inositol 1,3,4,5,6-pentakisphosphate 2-kinase gene, associated lethality, and tissue distribution of 2-kinase expression
Authors: Verbsky John , Lavine Kory , Majerus Philip W.
Published: June 2005

Many functions have been suggested for inositol 1,2,3,4,5,6-hexakisphosphate (InsP
6
), including mRNA export, nonhomologous end-joining, endocytosis, and ion channel regulation. However, it remains to be demonstrated that InsP
6
is necessary for
in vivo
survival. We previously isolated a cDNA encoding the mammalian inositol 1,3,4,5,6-pentakisphosphate (InsP
5
) 2-kinase (2-kinase), the enzyme that converts InsP
5
to InsP
6
. We used the sequence to search the BayGenomics databases and identify an ES cell line (XA232) that has a gene trap construct embedded in the 2-kinase gene. We obtained a mouse from this line, produced heterozygotes, and confirmed that the heterozygotes contain the trapping construct and have diminished 2-kinase activity. Breeding the XA232 heterozygotes produced no homozygous offspring; thus, loss of 2-kinase is lethal in mice. Dissections of embryonic day-8.5 uteri yielded no homozygous embryos; thus, the mice die before day 8.5 postcoitum. The gene trap construct contains a β-galactosidase/neomycin reporter gene, allowing us to stain heterozygotes for β-galactosidase to determine tissue-specific expression of 2-kinase protein. 2-kinase is expressed in the hippocampus, the cortex, the Purkinje layer of the cerebellum in the brain, in cardiomyocytes, and in the testes of adult mice. At day 9.5 postcoitum, 2-kinase was expressed in the notochord, the ventricular layer of the neural tube, and the myotome of the somites. Intense staining was also seen in the yolk sac, suggesting that InsP
6
is necessary for yolk sac development or function. Furthermore, failure of yolk sac development or function is consistent with the early lethality of 2-kinase embryos.
An essential role for an inositol polyphosphate multikinase, Ipk2, in mouse embryogenesis and second messenger production
Authors: Frederick Joshua P. , Mattiske Deidre , Wofford Jessica A. , Megosh Louis C. , Drake Li Yin , Chiou Shean-Tai , Hogan Brigid L. M. , York John D.
Published: June 2005

Phospholipase C and several inositol polyphosphate kinase (IPK) activities generate a branched ensemble of inositol polyphosphate second messengers that regulate cellular signaling pathways in the nucleus and cytoplasm. Here, we report that mice deficient for Ipk2 (also known as inositol polyphosphate multikinase), an inositol trisphosphate and tetrakisphosphate 6/5/3-kinase active at several places in the inositol metabolic pathways, die around embryonic day 9.5 with multiple morphological defects, including abnormal folding of the neural tube. Metabolic analysis of
Ipk2
-deficient cells demonstrates that synthesis of the majority of inositol pentakisphosphate, hexakisphosphate and pyrophosphate species are disrupted, although the presence of 10% residual inositol hexakisphosphate indicates the existence of a minor alternative pathway. Agonist induced inositol tris- and bis-phosphate production and calcium release responses are present in homozygous mutant cells, indicating that the observed mouse phenotypes are a result of failure to produce higher inositol polyphosphates. Our data demonstrate that Ipk2 plays a major role in the synthesis of inositol polyphosphate messengers derived from inositol 1,4,5-trisphosphate and uncovers a role for their production in embryogenesis and normal development.
The degradation of lignin and quantitative aspects of ruminant digestion
Authors: Porter P. , Singleton A. G.
Published: June 2005

1. The technique for the quantitative estimation of lignin by digestion with 72% H2S04has been investigated. Two methods of pretreatment designed to eliminate interference products of carbohydrates and proteins were compared, namely (a) acid and pepsin and (b) acid detergent. The latter technique gave low lignin yields owing to the colloidal dispersion of lignin in the acid detergent treatment. Erroneous results arise from an inadequate digestion in 72% H2SO4. It was found preferable to filter the product lignin without prior dilution of the acid since white particles of material, assumed to be cellulose, flocculated from solution on dilution. Also there is some loss due to colloidal dispersion of lignin during refluxing in dilute acid.

2. Analysis of soda lignin and sulphuric acid lignin preparations from hay, duodenal contents and faeces of sheep with exteriorized flow through a re-entrant duodenal fistula provided evidence for the degradation of lignin by digestive processes. Demethoxylation of lignin occurred mainly in the stomach, suggesting that this was the main site of breakdown.

3. A new displacement method of measuring duodenal flow is described. Quantitative results obtained also indicate that lignin is degraded mainly in the stomach to the extent of about 10%.

4. These results suggest that faecal lignin is an adequate marker for the estimation of duodenal flow, and hence of the extent of changes in the stomach and intestines respectively.
Acute in vivo studies on glucose absorption from the small intestine of lambs, sheep and rats
Authors: White R. G. , Williams V. J. , Morris R. J. H.
Published: June 2005

1. Rates of disappearance of glucose from ligated loops of small intestine in lambs, adult sheep and young rats were studied. The concentration of glucose in the lumen decreased exponentially with time, suggesting that within a range of concentrations of 166–277 m-moles/l glucose was absorbed mainly by passive diffusion.

2. The rate of absorption of glucose from a 166 mM-solution based on either zero or first order kinetics and expressed as m-moles/m small intestine per h decreased along the intestine from the duodenum to the ileum in lambs and rats. The decrease was slight in adult sheep.

3. The total absorptive capacity of the small intestine of adult grazing sheep for glucose from 166 mM-solutions (06 m-moles/kg body-weight per h) was approximately 25% of that for lambs less than 1 week of age.

4. Young rats had a greater absorptive capacity of the small intestine (12.9m-moles/kg body-weight per h) than adult sheep of about 40 kg body-weight (0.6 m-moles/kg body-weight per h) and this largely reflected a longer small intestine per unit body-weight.

5. The absorptive capacity of lambs for glucose was greater when the level of voluntary lactose intake was increased before an experiment. The absorptive capacity of the ileum of adult sheep given wheat was greater than that of grazing adult sheep.

6. Developmental changes in glucose absorption are discussed in relation to normal changes in diet and to changes in the morphology of the small intestine with age.
Metabolism of nitrogenous compounds in the large intestine of sheep
Authors: Hecker J. F.
Published: June 2005

1. The deamination, ureolytic and proteolytic activities and rates of cellulolysis and gas production in large intestinal contents have been compared with those activities and rates in rumen contents of sheep.

2. Large intestinal contents produced ammonia. The rate of ammonia production was greater in caecal contents than in faeces. Incubation of caecal contents under toluene resulted in decreased production of ammonia and volatile fatty acids and an increase in the concentration of αamino nitrogen.

3. Proteolytic activity of large intestinal contents was much greater than that of rumen contents. There was little difference in proteolytic activity between caecal or faecal contents and their liquors whereas the activity in rumen whole contents was greater than in rumen liquor. Some proteolytic activity was present in caecal and faecal cell-free liquors but none was present in rumen cell-free liquor.

4. Deaminase activity was greater in rumen than in caecal contents or faeces. The activity in rumen liquor was less than half that in rumen whole contents.

5. Urease activity of caecal contents was less than that of faeces or of rumen contents.

6. The rate of gas production in rumen contents was less than that in caecal contents. The rate in faeces was low. Less gas was produced in rumen liquor than in rumen contents, whereas there was little difference between rates in caecal liquor and whole contents.

7. Rates of breakdown of cellulose in vivo were similar in the rumen and the caecum.
Chemical composition of growth in nestling blackbirds and thrushes
Authors: Bilby Lorette W. , Widdowson Elsie M.
Published: June 2005

1. The bodies of twenty-three nestling blackbirds and twenty-one nestling thrushes were analysed at different ages for water, fat, nitrogen, calcium, phosphorus, sodium, potassium and magnesium. These birds grow from a weight of 5 g at hatching to 70 and 50 g respectively when they leave the nest 12–13 d later.

2. The concentration of N in the bodies doubled, while Ca increased seven to eight times during this period, so that the total amount of Ca in the body increased by about 100 times.

3. The femurs of the newly hatched birds were very immature and contained little Ca or collagen but in the fledgelings the femurs were as well calcified as those of 17-d-old chicks.

4. The gastro-intestinal tracts of the birds contained large amounts of Ca. Their food consists of caterpillars, adult insects and earthworms, none of which have much Ca in their tissues but their gut contents may contain much Ca. It is suggested that it is the gut contents of these invertebrates that provide nestling birds with Ca.
Effects of dietary supplements of newly growing heather on the breeding of captive red grouse
Authors: Moss R. , Watson A. , Parr R. , Glennie W.
Published: June 2005

1. The effects of dietary supplements of heather at different stages of growth on the breeding of captive red grouse were studied.

2. A supplement of heather which was beginning to grow in spring stimulated captive red grouse to lay more eggs and to lay at a faster rate than birds given a supplement of dormant winter heather.

3. Although laying was stimulated, no significant effect on the date of laying, the hatchability of the eggs or the survival of the young was demonstrated; however, the possibility of such effects occurring in the wild is not ruled out.

4. The experimental effect occurred although the heather formed only a small proportion of a largely artificial diet, which provided a high plane of nutrition in terms of known nutrients.

5. The effect is attributed to an unidentified factor contained in the new growth.
The erythrocyte membrane in kwashiorkor
Authors: Coward W. A.
Published: June 2005

1. Erythrocytes from Ugandan children with untreated kwashiorkor had membranes containing larger amounts of lecithin than erythrocytes collected during the recovery phase.

2. The passive permeability of the erythrocyte membrane to glycerol and thiourea was reduced in kwashiorkor and returned to a more normal value on treatment.

3. The results are discussed in the light of similar findings of high erythrocyte lecithin concentrations in various liver diseases.
Studies of the food intake of sheep at a single meal
Authors: Ternouth J. H. , Beattie A. W.
Published: June 2005

1. Experiments are described in which the food intake and the water intake of sheep at a single meal were measured. The sheep were offered lucerne chaff ad lib. for 2 h only each day.

2. Following the peritoneal infusion of physiological saline the food intake increased, while the injection of a diuretic before feeding caused the food intake to be decreased.

3. In eight experiments the osmolality of the ruminal liquor was increased by the addition to the rumen of NaCl, KCl or the salts of volatile fatty acids in 250 ml water. The decrease in food intake was related to the osmolality, but not to the energy content, of the added electrolyte solution. In a further experiment, sheep receiving a highly digestible lucerne chaff, containing 1% (w/w) NaCl, increased their food intake when water was added to the rumen. Other workers have concluded that gastric osmolality is an important variable in the control of food intake in monogastric animals. The results of the eight experiments now described suggest that ruminal osmolality is of similar importance in ruminants.

4. It is suggested that all these observations are consistent with the theory, which has been proposed for non-ruminant animals, that the food intake at a single meal may be related to the degree of tissue hydration at the beginning of the meal.
The extent of release of encapsulated methionine in the intestine of cattle
Authors: Neudoerffer T. S , Duncan D. B , Horney F. D
Published: June 2005

1. Factors affecting the release of methionine from kaolin-saturated-fat capsules in the intestine of cattle were investigated. Bile and pancreatin were shown to be necessary for appreciable solution of the capsule.

2. The relationship between site of release and site of absorption was ascertained. One site was shown to be in the proximal duodenum the second longer site is in the distal duodenum and proximal jejunum. Encapsulated methionine was carried past the first absorption site.

3. The results of in vitro incubations confirmed by those of in vivo studies show that 60–65% of the methionine becomes available for absorption in the intestine.
The effect of siderosis and ascorbic acid depletion on bone metabolism, with special reference to osteoporosis in the Bantu
Authors: Wapnick A. A. , Lynch S. R. , Seftel H. C. , Charlton R. W. , Bothwell T. H. , Jowsey Jenifer
Published: June 2005

1. There is an association between iron overload, ascorbic acid deficiency and osteoporosis in middle-aged South African Bantu males. The iron overload contributes to the ascorbic acid deficiency by accelerating its oxidative catabolism. The object of the present investigation was to explore the possibility that the osteoporosis results from chronic ascorbic acid deficiency.

2. On quantitative microradiography, percentage bone-formation surface was normal but percentage bone-resorption surface was significantly increased in ten osteoporotic subjects compared with seven control subjects.

3. There was a significant inverse correlation between bone mineral density and liver storage iron concentration in thirty-five Bantu subjects. In thirteen individuals aged 39 years or less, liver storage iron concentration was significantly correlated with percentage bone-resorption surface.

4. Guinea-pigs deprived of ascorbic acid for 21 d exhibited both significantly diminished percentage bone-formation surface and increased percentage bone-resorption surface.

5. Guinea-pigs overloaded with iron by injections of iron dextran developed significantly reduced hepatic ascorbic acid concentrations and bone mineral densities; percentage bone-formation surface was significantly diminished and percentage bone-resorption surface significantly increased. Ascorbic acid injection largely prevented the bone changes.
Activation of pepsin (EC3.4.4.1) by heavy-metal ions including a contribution to the mode of action of copper sulphate in pig nutrition
Authors: Kirchgessner M. , Beyer M. G. , Steinhart H.
Published: June 2005

1. Kinetic experiments were done with pepsin (EC3.4.4.1) using haemoglobin as a substrate in the presence of different metal cations.

2. The activation of peptic hydrolysis with higher concentrations of cupric ions added to the reaction mixture was determined from turnover-rate curves in experiments with constant substrate concentration. With a Cu2+concentration greater than 1.67 × 10-4M activation was obtained

3. Nickel ions at a concentration of 8.33 × 10-4M and at higher concentrations also increased pepsin activity. Additions of ferrous ions and zinc ions had no effect.

4. Experiments were done using variable substrate concentrations in the presence of different Cu2+concentrations. The concentrations of haemoglobin ([S]) at half maximum velocity were determined. The double-reciprocal plots of [S]v.reaction velocity (v) (i.e. I/[S]v.I/v) had no common intersection point. Therefore the kinetics did not correspond to any of the known kinetics. The activation brought about by Cu2+cannot easily be explained by the study of the kinetics. Certain simple explanations of the phenomenon can be eliminated.
The measurement of production rates of volatile fatty acids in the caecum of the conscious rabbit
Authors: Parker D. S.
Published: June 2005

1. The decrease in specific radioactivity of individual volatile fatty acids (VFA) after a single injection of tracer was monitored. The results obtained indicated the occurrence of a first-order process.

2. Regression analysis indicated the high flux of VFA through the caecal pool, equivalent to 30% of the maintenance energy requirement of the animal.

3. Interconversion of VFA was monitored, and results indicated substantial synthesis of butyric acid from acetic acid.

4. Results were obtained from animals on two dietary regimens, and these were compared with results reported for other species.
The forms of vitamin B12in foods
Authors: Farquharson J. , Adams J. F.
Published: June 2005

1. The forms of vitamin B12were determined in foods, most of which had been prepared for consumption.

2. Five forms were detected: adenosylcobalamin, hydroxocobalamin, methylcobalamin, cyanocobalamin and sulphitocobalamin. Adenosylcobalamin and hydroxocobalamin were the predominant forms.

3. The intestinal absorption of [57Co] sulphitocobalamin was estimated and found to be lower than that of [58Co]cyanocobalamin.
Seasonal changes in the plasma retinol-binding holoprotein concentration of sheep
Authors: Glover J. , Jay Caroline , Kershaw R. C. , Reilly P. E. B.
Published: June 2005

1. Seasonal variations in plasma retinol-binding holoprotein concentration have been found in two groups of entire ewes and in a control group of wethers (castrated rams).

2. In each group retinol-binding holoprotein level was minimal in summer and increased to peak values in September just before the autumn breeding season.
Determination of nitrogen requirement for microbial growth from the effect of urea supplementation of a low N diet on abomasal N flow and N recycling in wethers and lambs
Authors: Allen Sarah A. , Miller E. L.
Published: June 2005

1. Plasma urea entry rate, urinary urea excretion and, by difference, urea recycling in the body, together with the flow of non-ammonia N through the abomasum and digestion of dry matter (dm) before the abomasum were determined in both wethers and lambs receiving cereal-starch diets supplemented with urea to give 60–120 g crude protein (N × 6.25)/kgdm.

2. Lambs excreted less urea in urine than wethers given the same diet.

3. Relationships between plasma urea entry rate or urine urea excretion rate and plasma urea concentration were different for lambs compared to wethers suggesting greater conser vation of body N by renal control in lambs.

4. Recycling of urea was not related to plasma urea concentration in wethers but was related exponentially in lambs, suggesting recycling is controlled rather than the result of simple diffusion from the blood to the gastro-intestinal tract.

5. Abomasal non-ammonia-N flow was similar for wethers and lambs and increased linearly with urea supplementation.

6.dmdigestion prior to the abomasum was not significantly altered, although there was a tendency for decreased digestion of the basal diet given to lambs.

7. Maximum microbial N flow to the abomasum was estimated as 30 g N/kg organic matter (OM) fermented in the rumen.

8. This work and the literature reviewed suggested maximum net microbial production can be obtained when the diet supplies an amount of fermentable N equal to the microbial N output. It is calculated the diet should supply approximately 26 g fermentable N/kg digestible OM or 1.8 g fermentable N/MJ metabolizable energy. This corresponds to a fermentable crude protein supply varying from 65 to 130 g/kg DM as digestible OM content increases from 400 to 800 g/kg DM.
Utilization of dried microbial cells grown on methanol in a semi-purified diet for growing pigs
Authors: D'Mello J. P. F. , Peers D. G. , Whittemore C. T.
Published: June 2005

1. Twenty-four pigs (mean body-weight 44 kg) were used to determine the digestibilities of energy, nitrogen and amino acids in dried microbial cells (DMC) grown on methanol and in white fish meal (WFM). N utilization and the excretion of various nitrogenous compounds were also studied.

2. Semi-purified diets containing DMC, WFM or no protein source were offered at the rate of 1 kg fresh food/d. Daily N intakes were 26.5, 24.7 and 0.65 g respectively.

3. Mean metabolic faecal N determined with the protein-free diet was 1.11 g/d (1.26 g/kg dry matter (dm) eaten) for the two experiments. The corresponding endogenous urinary N value was 2.91 g/d.

4. Daily urinary N output of pigs given the diet with WFM was significantly greater than that of pigs given the diet with DMC, with the result that N retention, net protein utilization and biological value were higher for pigs given DMC.

5. Apparent and true digestibility of amino acids were higher for the diet with DMC than for the diet with WFM.

6. N excretion in the form of ammonia, urea, uric acid and allantoin accounted for 81, 91 and 99% of the total N excreted by the groups given the protein-free diet, DMC and WFM respectively. Pigs given DMC excreted greater quantities of allantoin-N and less urea-N than pigs given WFM.
The digestion of yeast cell wall polysaccharides in veal calves
Authors: Gaillard Blanche D. E. , Van Weerden E. J.
Published: June 2005

1. The digestibility of the cell wall polysaccharides of an alkane-grown yeast in different parts of the digestive tract of two veal calves fitted with re-entrant cannulas at the end of the ileum was studied by replacing part of the skim-milk powder of their ‘normal’, milk-substitute (all-milk-protein) diet by yeast (yeast diet).

2. The lactose and glucose of both the all-milk-protein diet and the yeast diet were almost completely digested before the end of the ileum. During this digestion a small amount of oligosaccharides composed of galactose and glucose was synthesized. These oligosaccharides were digested again in the large intestine.

3. The constituent sugars of the water-soluble fraction of the yeast cell wall carbohydrates were glucose and mannose. The 0.5 m-sulphuric acid-hydrolysate of the water-insoluble fraction contained glucose and mannose and the 12 m-H2SO4-hydrolysate only glucose.

4. Digestibilities of these fractions over the whole gastrointestinal tract ranged from 0.77 to 0.90. Digestibilities measured at the end of the ileum varied considerably between the two animals and averaged only about 0.40.

5. These findings suggest that the cell wall polysaccharides of yeast are digested very little by the normal digestive enzymes of the calf's small intestine, but are used as a substrate by the bacterial flora which are mainly concentrated in the large intestine.
Changes in the alkaline phosphatase (EC 3.1.3.1) and inorganic pyrophosphatase (EC 3.6.1.1) activities of rat tissues during magnesium deficiency. The importance of controlling feeding pattern
Authors: Loveless B. W. , Heaton F. W.
Published: June 2005

1. The adoption of a meal-eating pattern of feeding by rats altered the alkaline phosphatase (EC 3.1.3.1) activity in serum and liver. It was therefore necessary to regulate the feeding pattern of both magnesium-deficient rats and control animals receiving a Mg-adequate diet in order to study the effect of the deficiency.

2. Mg deficiency decreased the activities of alkaline phosphatase and inorganic pyro-phosphatase (EC 3.6.1.1) in serum, kidney and tibia, but increased them in spleen.

3. Addition of a standard concentration of exogenous Mg to tissue extracts usually increased the activity of corresponding enzymes from Mg-deficient and control rats by the same proportion, indicating that the main effect of the deficiency was on the amount of enzyme present rather than on the efficiency of its operation.

4. Certain quantitative differences in the response to exogenous Mg and the activity ratio, alkaline phosphatase: inorganic pyrophosphatase were found between tissues from Mg-deficient and control rats. The significance of these are discussed in relation to the association of the two enzymic activities with the same protein molecule, and the possible occurrence of isoenzymes.
The effects of dietary thiamin on voluntary ethanol drinking and ethanol metabolism in the rat
Authors: Eriksson K. , Pekkanen Leena , Rusi Maija
Published: June 2005

1. The influence of a deficiency or surplus of thiamin in the diet on voluntary ethanol consumption, ethanol elimination rate and blood acetaldehyde concentration was studied in rats.

2. Both the high-thiamin diet containing 20 mg thiamin hydrochloride/kg and the thiamin deficient diet containing no measurable thiamin produced obvious functional effects on thiamin metabolism in rat tissues after 4 weeks as demonstrated by measurements of the blood transketolase (sedoheptulose-7-phosphate: D-glyceraldehyde-3-phosphate glycolaldehyde-transferase;EC2.2.1.1) activity and the extent of thiamin pyrophosphate-stimulation of the enzyme.

3. During the first week on the test diets the prospective ethanol free-choice groups had 1.72 M-ethanol as their only drinking-fluid. Subsequently they had a choice between ethanol and tap water for three weeks. During the free-choice period the rats on the high-thiamin diet drank only one-fifth as much ethanol as the rats given the optimum diet with 4 mg thiamin hydrochloride/kg.

4. The thiamin-deficient rats showed a significant tendency to increase ethanol drinking, when intake was expressed relative to total energy intake, but their intake of ethanol on a g/kg body-weight basis was approximately the same as that of the group given the optimum-diet.

5. The observed differences in voluntary ethanol drinking associated with different levels of dietary thiamin cannot be explained by changes in the ethanol elimination rate or the acetaldehyde accumulation in blood during the oxidation of ethanol.
Estimation of body fat in normal and obese mice
Authors: Rogers P. , Webb G. P.
Published: June 2005

1. Lee Index (weight (g0.33)÷ nasoanal length (mm)), density, body water and proportional weight of the gonadal fat pad were tested as estimates of body fat in a normal population of mice and a population which included obese mice.

2. In a normal population only body water and fat-pad weight correlated significantly with body fat.

3. In a population of normal and obese mice all four indices correlated significantly with body fat.

4. Lee Index had little advantage over weight: length as an estimate of body fat, and density did not correlate well enough to be used as a method of estimation.

5. Proportional weight of the gonadal fat pad is recommended as a simple reliable estimate of body fat in normal or obese mice.
Vitamin C status, serum cholesterol levels and bile composition in the pregnant guinea-pig
Authors: Jenkins S. A.
Published: June 2005

1. Pregnant guinea-pigs receiving a low dose of L-ascorbic acid (0.2 mg/100 g body-weight per d) developed a hypercholesterolaemia in the third trimester of pregnancy, whereas no change in serum cholesterol levels was observed in pregnant animals receiving a higher dose of the vitamin (2 mg/100 g body-weight per d).

2. Pregnancy in the group of guinea-pigs receiving the higher dose of L-ascorbic acid was associated with an increased biliary secretion of bile acids. No change was observed in the biliary secretion of bile acids in pregnant animals receiving the lower dose of L-ascorbic acid, but these animals secreted significantly more cholesterol.

3. Changes in the biliary secretion of cholesterol and bile acids in the pregnant guinea-pig according to L-ascorbic acid intake were reflected in the composition of the gall-bladder bile. Thus, the gall-bladder bile of guinea-pigs receiving the lower dose of L-ascorbic acid contained more cholesterol, while the gall-bladder bile of those animals receiving the higher dose of the vitamin had a higher content of bile acids.

4. The increased cholesterol content of the gall-bladder of pregnant guinea-pigs receiving the lower dose of L-ascorbic acid resulted in decreased bile acid:cholesterol and phospholipid: cholesterol values, conditions predisposing to cholelithiasis.
Dietary tryptophan level and the enzymes of tryptophan NAD pathway
Authors: Satyanarayana U. , Narasinga Rao B. S.
Published: June 2005

1. Dietary tryptophan was found to regulate the activities of tryptophan oxygenase (EC I. 13.I. 12)and quinolinate phosphoribosyltransferase (EC z.4. 2a) in liver.

2. With increasing tryptophan concentration in the diet containing 100 g protein/kg, tryptophan oxygenase activity increased while that of quinolinate phosphoribosyltransferase decreased. The response of these enzymes to dietary tryptophan at lower dietary protein level (25 g/kg) was not significant.

3. Liver nicotinate phosphoribosyltransferase (EC 2.4.2. 11)activity and kidney picolinate carboxylase (EC 4. I.I. 45) activity were unaltered with different tryptophan concentrations in the diet.

4. The response of various biochemical measurements was dependent on the tryptophan intake and the changes were marked below and above the requirement level of tryptophan.

5. It is suggested that the urinary excretion of quinolinic acid and N'-methylnicotinamide may be useful in assessing the tryptophan nutritional status and its requirement.
Nutritional evaluation of the germ meal and its protein isolate obtained from the carob seed (Ceratonia siliqua) in the rat
Authors: Drouliscos N. J. , Malefaki Vastliki
Published: June 2005

1. Evaluation of the germ meal (CGM) of carob seed (Ceratonia siliqua) and its protein isolate was carried out with weanling rats. Comparisons were made with casein, soya-bean meal, whole defatted egg and a soya-bean protein isolate (Promine-D) as protein sources. The growth-promoting effects and certain biological indices were evaluated using the protein efficiency ratio (PER), biological value (BV) and net protein utilization (NPU) bioassay procedures.

2. The unsupplemented CGM had a PER of 1.66 ± 0.09 and an NPU of 0.58 ± 0.013. Addition of DL-methionine at 4, 8 and 12 g/kg diet resulted in a PER of 1.95 ± 0.11, 2.01 ± 0.11 and 1.90 ± 0.11 respectively. The corresponding BV values were 0.80 ± 0.003, 0.78 ± 0.015 and 0.74 ± 0.011, and those for NPU 0.69 ± 0.013, 0.66 ± 0.026 and 0.63 ± 0.020 respectively. The addition of amino acids improved the PER (2.24–2.59), BV (0.78–0.79) and NPU (0.71–0.73) values.

3. The BV and NPU assays for the unsupplemented carob germ isolate were low (BV 0.36 ± 0.016, NPU 0.35 ± 0.015). Supplementation with amino acids resulted in a positive increase with values of 0.66 ± 0.013 and 0.64 ± 0.013 for BV and NPU respectively.