Dimerization of bovine F1-ATPase by binding the inhibitor protein, IF1

In mitochondria, the hydrolytic activity of ATP synthase is regulated by a natural inhibitor protein, IF(1). The binding of IF(1) to ATP synthase depends on pH values, and below neutrality, IF(1) forms a stable complex with the enzyme. Bovine IF(1) has two oligomeric states, dimer and tetramer, depending on pH values. At pH 6.5, where it is active, IF(1) dimerizes by formation of an antiparallel alpha-helical coiled-coil in its C-terminal region. This arrangement places the inhibitory N-terminal regions in opposition, implying that active dimeric IF(1) can bind two F(1) domains simultaneously. Evidence of dimerization of F(1)-ATPase by binding to IF(1) is provided by gel filtration chromatography, analytical ultracentrifugation, and electron microscopy. At present, it is not known whether IF(1) can bring about the dimerization of the F(1)F(0)-ATPase complex.

Dominant and recessive inheritance of morbid obesity associated with melanocortin 4 receptor deficiency

Over 20 severely obese subjects in 11 independent kindreds have been reported to have pathogenic heterozygous mutations in the gene encoding the melanocortin 4 receptor (MC4R), making this the most common known monogenic cause of human obesity. To date, the detailed clinical phenotype of this dominantly inherited disorder has not been defined, and no homozygous subjects have been described. We determined the nucleotide sequence of the entire coding region of the MC4R gene in 243 subjects with severe, early-onset obesity. A novel two-base pair GT insertion in codon 279 was found in two unrelated subjects, and four novel missense mutations, N62S, R165Q, V253I, C271Y, and one mutation (T112M) reported previously were found in five subjects. N62S was found in homozygous form in five children with severe obesity from a consanguineous pedigree. All four heterozygous carriers were nonobese. Several features of the phenotype, e.g. hyperphagia, tendency toward tall stature, hyperinsulinemia, and preserved reproductive function, closely resemble those reported previously in Mc4r knock-out mice. In addition, a marked increase in bone mineral density was seen in all affected subjects. In transient transfection assays, the N62S mutant receptor showed a responsiveness to alphaMSH that was intermediate between the wild-type receptor and mutant receptors carrying nonsense and missense mutations associated with dominantly inherited obesity. Thus MC4R mutations result in a syndrome of hyperphagic obesity in humans that can present with either dominant or recessive patterns of inheritance.

Cloning, sequencing and expression of the gene for flavodoxin from Megasphaera elsdenii and the effects of removing the protein negative charge that is closest to N(1) of the bound FMN

The gene for the electron-transfer protein flavodoxin has been cloned from Megasphaera elsdenii using the polymerase chain reaction. The recombinant gene was sequenced, expressed in an Escherichia coli expression system, and the recombinant protein purified and characterized. With the exception of an additional methionine residue at the N-terminus, the physico-chemical properties of the protein, including its optical spectrum and oxidation-reduction properties, are very similar to those of native flavodoxin. A site-directed mutant, E60Q, was made to investigate the effects of removing the negatively charged group that is nearest to N(1) of the bound FMN. The absorbance maximum in the visible region of the bound flavin moves from 446 to 453 nm. The midpoint oxidation-reduction potential at pH 7 for reduction of oxidized flavodoxin to the semiquinone E2 becomes more negative, decreasing from -114 to -242 mV; E1, the potential for reduction of semiquinone to the hydroquinone, becomes less negative, increasing from -373 mV to -271 mV. A redox-linked pKa associated with the hydroquinone is decreased from 5.8 to < or = 4.3. The spectra of the hydroquinones of wild-type and mutant proteins depend on pH (apparent pKa values of 5.8 and < or = 5.2, respectively). The complexes of apoprotein and all three redox forms of FMN are much weaker for the mutant, with the greatest effect occurring when the flavin is in the semiquinone form. These results suggest that glutamate 60 plays a major role in control of the redox properties of M. elsdenii flavodoxin, and they provide experimental support to an earlier proposal that the carboxylate on its side-chain is associated with the redox-linked pKa of 5.8 in the hydroquinone.

Evaluation of role of concentration and molecular weight of oat beta-glucan in determining effect of viscosity on plasma glucose and insulin following an oral glucose load

Data from clinical studies established that there was an inverse linear relationship between measures of postprandial blood glucose and insulin responses to an oral glucose load, consumed in a drink, and the logarithm of viscosity of the drink. These data have been re-analysed using concentration and molecular weight as the dependent variables. Molecular weight (M) of the beta-glucans used was determined using high-performance size exclusion chromatography equipped with a triple detector system of right angle light scattering, viscometry and refractive index. A significant relationship between changes in peak blood glucose and a combination of logarithm of the concentration and logarithm of M was found.

Possible Role of Trichothecene Mycotoxins in Virulence of Fusarium graminearum on Maize

Trichothecene-producing and -nonproducing Fusarium graminearum strains were tested for their ability to cause Gibberella ear rot in field trials at two locations-Ottawa, Ontario, and Peoria, Illinois-in 1996. Maize ears were inoculated with wild-type or transgenic F. graminearum strains in which the trichothecene biosynthetic pathway had been disabled by the specific disruption of the trichodiene synthase gene and with a derivative revertant strain in which trichothecene production had been restored through recombination. A silk channel inoculation method was employed at both locations. In addition, a kernel puncture inoculation method was used at the Ontario location. Harvested maize ears were analyzed for visual disease severity, grain yield, deoxynivalenol (DON) concentration, and fungal biomass by quantitative polymerase chain reaction (PCR) and/or ergosterol quantitation. There was a significant correlation (r= 0.86) between data obtained from the two different methods of quantifying fungal biomass. The trichothecene-nonproducing strains were still pathogenic but appeared less virulent on maize than the trichothecene-producing progenitor and revertant strains, as assayed by most parameters. This suggests that the trichothecenes may act as virulence factors to enhance the spread of F. graminearum on maize.

Evaluation of some newer matrix metalloproteinases

Recombinant protein expression techniques have been utilized to facilitate the biochemical and cell biological characterization of human matrix metalloproteinases (MMPs). The importance of the membrane type 1 MMP (MMP 14) in the regulation of pericellular proteolysis, either directly or through the activation of MMP-2, MMP-9, and MMP-13 has been identified. Studies on an in vitro chondrocyte-like cell and an in vivo cartilage repair model indicated that such MT1 MMP-regulated activation cascades are physiologically feasible. MMP19 shows a limited sequence identity with other MMPs and may represent a novel subclass. However, analysis of the recombinant protein identified a number of biochemical properties typical of the MMP family.

Regulated nuclear localisation of the yeast transcription factor Ace2p controls expression of chitinase (CTS1) in Saccharomyces cerevisiae

The yeast transcription factor Ace2p regulates expression of the chitinase gene CTS1 in a cell cycle-dependent manner. Nuclear localisation of Ace2p is restricted to late M and early G phases of the mitotic cell cycle. We show here that this nuclear localisation is directly associated with regulation of CTS1 expression. Using a version of Ace2p tagged with a c-myc epitope, we show that the protein is excluded from the nucleus of cells during most phases of the mitotic cell cycle. A mutant derivative in which one threonine and two serine residues, which are candidate phosphorylation sites, were replaced by alanine (to mimic constitutive dephosphorylation) is localised in the nucleus throughout the cell cycle. The mechanism of localisation of Ace2p therefore involves regulation of its phosphorylation state, and closely resembles that used by the homologous transcription factor Swi5p. The wild-type Ace2 protein associates with Cdc28p in vivo, suggesting this may be the kinase that mediates the phosphorylation event. The stability of the protein is greatly reduced in a mutant that is constitutively localised to the nucleus, but is restored in a deletion derivative which remains in the cytoplasm. Ace2p is therefore controlled throughout the cell cycle at three levels: transcription, nuclear localisation, and proteolysis.

Mechanisms for pro matrix metalloproteinase activation

The activation of pro matrix metalloproteinases (MMPs) by sequential proteolysis of the propeptide blocking the active site cleft is regarded as one of the key levels of regulation of these proteinases. Potential physiological mechanisms including cell-associated plasmin generation by urokinase-like plasminogen activator, or the action of cell surface MT1-MMPs appear to be involved in the initiation of cascades of pro MMP activation. Gelatinase A, collagenase 3 and gelatinase B may be activated by MT-MMP based mechanisms, as evidenced by both biochemical and cell based studies. Hence the regulation of MT-MMPs themselves becomes critical to the determination of MMP activity. This includes activation, assembly at the cell surfaces as TIMP-2 complexes and subsequent inactivation by proteolysis or TIMP inhibition.

Ace2p, a regulator of CTS1 (chitinase) expression, affects pseudohyphal production in Saccharomyces cerevisiae

Some diploid strains of Saccharomyces cerevisiae can grow both as a spherical yeast form and as a filamentous pseudohyphal form. Most yeasts capable of forming pseudohyphae possess a functional FLO8 gene. We show that disrupting the ACE2 transcription factor results in the production of pseudohyphae in a flo8-1 background. Disrupting the CTS1 (chitinase) gene also produces pseudohyphal growth in this background, but at a reduced level. Invasion of solid media by haploid and diploid cells is increased in ACE2 disruptions, but the diploids adhere poorly to the agar. Sigma1278b-derived strains, which generally produce pseudohyphae, have about 30-fold lower chitinase activity than other strains.

Co-ordinated and cellular specific induction of the components of the IGF/IGFBP axis in the rat brain following hypoxic-ischemic injury

Insulin-like growth factor 1 (IGF-1) is induced after hypoxic-ischemic (HI) brain injury, and therapeutic studies suggest that IGF-1 may restrict delayed neuronal and glial cell loss. We have used a well-characterised rat model of HI injury to extend our understanding of the modes of action of the IGF system after injury. The induction of the IGF system by injury was examined by in situ hybridization, immunohistochemistry, Northern blot analysis, RNase protection assay and reverse transcriptase-polymerase chain reaction (RT-PCR). IGF-1 accumulated in blood vessels of the damaged hemisphere within 5 h after a severe injury. By 3 days, IGF-1 mRNA was expressed by reactive microglia in regions of delayed neuronal death, and immunoreactive IGF-1 was associated with these microglia and reactive astrocytes juxtaposed to surviving neurones surrounding the infarct. Total IGF-1 receptor mRNA was unchanged by the injury. IGFBP-2 mRNA was strongly induced in reactive astrocytes throughout the injured hemisphere, and IGFBP-3 and IGFBP-5 mRNA were moderately induced in reactive microglia and neurones of the injured hippocampus, respectively. IGFBP-6 mRNA was induced in the damaged hemisphere by 3 days and increased protein was seen on the choroid plexus, ependyma and reactive glia. In contrast, insulin II was not induced. These results indicate cell type-specific expression for IGF-1, IGFBP-2,3,5 and 6 after injury. Our findings suggest that the IGF-1 produced by microglia after injury is transferred to perineuronal reactive astrocytes expressing IGFBP-2. Thus, modulation of IGF-1 action by IGFBP-2 might represent a key mechanism that restricts neuronal cell loss following HI brain injury.

Cloning and analysis of the genes for a novel electron-transferring flavoprotein from Megasphaera elsdenii. Expression and characterization of the recombinant protein

The genes that encode the two different subunits of the novel electron-transferring flavoprotein (ETF) from Megasphaera elsdenii were identified by screening a partial genomic DNA library with a probe that was generated by amplification of genomic sequences using the polymerase chain reaction. The cloned genes are arranged in tandem with the coding sequence for the beta-subunit in the position 5' to the alpha-subunit coding sequence. Amino acid sequence analysis of the two subunits revealed that there are two possible dinucleotide-binding sites on the alpha-subunit and one on the beta-subunit. Comparison of M. elsdenii ETF amino acid sequence to other ETFs and ETF-like proteins indicates that while homology occurs with the mitochondrial ETF and bacterial ETFs, the greatest similarity is with the putative ETFs from clostridia and with fixAB gene products from nitrogen-fixing bacteria. The recombinant ETF was isolated from extracts of Escherichia coli. It is a heterodimer with subunits identical in size to the native protein. The isolated enzyme contains approximately 1 mol of FAD, but like the native protein it binds additional flavin to give a total of about 2 mol of FAD/dimer. It serves as an electron donor to butyryl-CoA dehydrogenase, and it also has NADH dehydrogenase activity.

Membrane-type matrix metalloproteinases 1 and 2 exhibit broad-spectrum proteolytic capacities comparable to many matrix metalloproteinases

Soluble proenzyme forms of the catalytic domains of membrane-type matrix metalloproteinases 1 and 2 (MT1-MMP and MT2-MMP) and a form of MT1-MMP containing the catalytic and hemopexin domains were expressed as soluble recombinant proteins. Purified, activated forms of the MT-MMP were shown to degrade fibronectin, tenascin, nidogen, aggrecan and perlecan. Only MT2-MMP showed activity against laminin. MT1-MMP retaining the hemopexin domain was able to specifically cleave native type-I and type-III collagens into the 3/4-1/4 fragments typical of the specific collagenases. The catalytic domain alone did not retain this activity. The MT-MMP did not degrade interleukin-1beta, but, similarly to many other MMP, could process a pro [tumor necrosis factor (TNF) alpha] fusion protein to release mature TNF. However, the latter was subsequently degraded into smaller fragments. These results demonstrate that, in addition to their ability to activate other MMP, such as progelatinase A/proMMP2 and procollagenase-3/proMMP13, MT-MMP degrade a number of extracellular matrix macromolecules. Their location at the surface of cells implies that they could play a significant role in the modulation of cell-matrix interactions.

Visual function in young IDDM patients over 8 years of age. A 4-year longitudinal study

OBJECTIVE

To carry out a longitudinal study of visual functions in young patients over the age of 8 years with IDDM and to assess the impact of metabolic control on the presence of diabetic retinopathy.

RESEARCH DESIGN AND METHODS

There were 37 young IDDM patients from the Paediatric and Adolescent Clinic at the University Hospital of Wales studied annually for 4 years, with a control group of 24 healthy subjects observed over a 2-year period. Assessment of visual functions included visual acuity, color vision, and contrast sensitivity. Ophthalmoscopy and retinal photography were used to determine the presence or absence of diabetic retinopathy. In addition, pubertal status and metabolic control (glycosylated hemoglobin) were determined at each visit.

RESULTS

Patients with IDDM demonstrate abnormal color vision and contrast sensitivity compared with the control group (P < 0.05), but visual acuity was unaffected. Visual functions were not significantly different between those IDDM patients with and without retinopathy. After 4 years, diabetic retinopathy was present in 43% of the group and was related to diabetes duration and metabolic control (P < 0.05).

CONCLUSIONS

Visual function testing could not distinguish between those IDDM patients with and without retinopathy, but the color vision and contrast sensitivity in those with IDDM were significantly impaired compared with the control group. The presence of retinopathy was related to the duration of diabetes and metabolic control. It is important to ensure that good glycemic control and regular attendance for retinopathy screening is encouraged in the adolescent patients.

Non-organic failure to thrive complicated by benign intracranial hypertension during catch-up growth

Severe non-organic failure to thrive associated with physical and emotional abuse including food deprivation was diagnosed in a 9-y-old boy. Rapid catch-up growth (weight and height) followed change of carer. Recovery of poor growth hormone response to clonidine stimulation was associated with benign intracranial hypertension accompanied by headaches and vomiting. Possible mechanisms are discussed.

Sensory analysis of meat from broiler chickens fed diets containing hulless oats (Avena nuda)

New cultivars of hulless or naked oats have metabolizable energy comparable to corn but with higher protein content and quality than corn (Burrows et al. 1993). Although there is documented evidence on poultry performance that hulless oats are a suitable feedstuff for poultry, there is little documentation on the effect of hulless oats as a poultry feedstuff on the sensory qualities of the meat. The objectives of this study were to investigate the effects of increasing dietary levels of hulless oats on the sensory quality of the broiler chicken meat and to ascertain if rancidity had developed during 3 mo of cold storage. Hulless oat dietary levels were assigned to a factorial arrangement of two sexes of broilers, three broiler starter diets (S0, S250, S500 g kg−1) and four grower diets (G0, G250, G500 and G750 g kg−1). Hulless oats of each diet replaced portions of the corn and soybeans of the control diet (S0/G0). Tenderness, juiciness, flavour intensity and muscle fibre integrity of the light meat; and tenderness, rubberiness, stringiness, juiciness and flavour intensity of the dark meat were evaluated by six selected assessors. Cooking data indicated a significant sex effect for oven-ready weight and grower oats level effect for weight loss during cooking. There were significant grower effects for tenderness and juiciness (P ≤ 0.05) of light meat. In the dark meat there was a significant sex effect (P ≤ 0.05) for stringiness; starter effect (P ≤ 0.05) for flavour; and grower effect for tenderness and juiciness (P ≤ 0.05). From a sensory perspective it appears that replacement of corn and soybeans in broiler grower diets by 500 g kg−1 of hulless oats decreases some sensory quality parameters. This was not found at 250 g kg−1 hulless oats. Key words: Oat (hulless, naked), broiler chicken, sensory analysis, thiobarbituric acid

Comparison of the polyethylene glycol antiglobulin test and the use of enzymes in antibody detection and identification

BACKGROUND

The polyethylene glycol indirect antiglobulin test for detection of red cell antibodies was compared with a proven, highly sensitive test system using papain.

STUDY DESIGN AND METHODS

Parallel, prospective testing of 1508 samples with polyethylene glycol and with albumin and papain evaluated the sensitivity and specificity of polyethylene glycol. Retrospective analysis of antibody specificities was performed for the 2 years before and the 2 years after the institution of polyethylene glycol testing.

RESULTS

Of 1508 prospective screens, 53 (3.5%) had discordant results: 5 were positive only in polyethylene glycol and 48 were positive only in albumin and papain. Upon antibody identification, the 5 samples that were positive only in polyethylene glycol showed 1 anti-D, 2 warm autoantibodies, and 2 false-positive results. The 48 samples that were positive only in albumin and papain showed 1 each of the following: anti-Le(b); anti-P1; anti-S; high-titer, low-avidity antibody; and cold autoantibody; there were 43 false-positive results. False-positive results totaled 12 (0.8%) with polyethylene glycol and 53 (3.5%) with albumin and papain. The retrospective analysis of antibody specificity with polyethylene glycol showed a significant increase in the detection of Fy(a) and/or Fy(b) (p < 0.0002) and Jk(b) (p < 0.0002) antibodies and a decrease in the detection of Le(a) and/or Le(b) antibodies (p < 0.0002).

CONCLUSION

Polyethylene glycol retained the high sensitivity of the albumin and papain, while significantly lowering the number of false-positive results and decreasing the detection of antibodies of doubtful clinical significance.

A comparison of five protein sources as supplements for growing steers fed grass silage

An experiment conducted at three sites in eastern Canada, Kapuskasing, Lennoxville and Nappan, compared the efficacy of five protein sources as supplements for growing steers fed grass silage. For 20 wk, a total of 171 growing beef steers, average initial weight 247 kg, were offered grass silage ad libitum, either alone or supplemented with isonitrogenous amounts of FM, SBM, CM, a mixture of corn gluten meal and blood and, at two sites, MM. There were no significant treatment-by-site interactions for any of the parameters measured. Combined across the three sites, liveweight gain was low on the all-silage diet, 0.51 kg d−1, and FM increased gain by 0.44 kg d−1 or 86%. Soybean meal, CM and the CGM/BM increased liveweight gain by an average of 0.35 kg d−1 or 68%, while MM increased gain by 0.28 kg d−1 or 58%. All supplements increased liveweight gain (P < 0.001) with FM being superior to the other sources (P < 0.01). The supplements increased total DM intake (kg 100 kg LW−1, P < 0.01) but had no effect on silage intake (P > 0.05). Gain/feed ratio was 0.091 on the all-silage diet and was increased (P < 0.001) by all supplements, with FM (0.142) being superior (P < 0.01) to the other protein sources which averaged 0.129. The supplements did not affect organic matter digestion (P = 0.06) in measurements made at Lennoxville. Rumen degradability did not explain the differences in the extent to which the protein sources improved the performance of growing steers. Key words: Steers, growth, grass silage, protein supplements

A case study with delayed renal graft function as a consequence of severe secondary hyperparathyroidism

A 36-year-old Arab man had been treated with hemodialysis for 6 years. During that time he received no treatment with phosphate binders or 1,25-dihydroxy-vitamin D3. He thus developed a severe form of secondary hyperparathyroidism and presented with bone disease, pseudoclubbing of the fingers, and soft-tissue calcification. He was transplanted with a kidney from a living donor, but there was no immediate onset in renal function. A biopsy showed crystal deposition that was thought to be due to his secondary hyperparathyroidism. Four weeks after the renal transplantation with still no evidence of a functioning graft, a parathyroidectomy was performed. A few days later, graft function recovered, and the amount of the crystals in the kidney decreased. There is strong evidence that the severe secondary hyperparathyroidism prevented the onset of renal function. It is concluded that crystal deposition with graft dysfunction should be an absolute indication for parathyroidectomy.

Yeast homologue of mammalian Ran binding protein 1

A Saccharomyces cerevisiae gene (HTN1) that encodes a homologue of mouse Ran binding protein 1 (RanBP1, also known as HTF9A) was identified, cloned and sequenced. The two proteins are 51% identical in sequence. The HTN1 protein may interact with yeast GSP1, GSP2, and PRP20 proteins in an intracellular signalling pathway equivalent to the mammalian RanBP1-Ran/TC4-RCC1 pathway. RanBP1 homologues also exist in worms and rice.

Longitudinal study of visual functions in young insulin dependent diabetics

The aim of this study was to compare the visual functions of a group of young insulin dependent diabetes mellitus patients (IDDMs), (n = 42) with an age and sex matched control group (n = 24). Examinations were carried out every 3 months for 2 years. There were no significant differences in visual acuity between IDDMs and control subjects. The IDDMs made significantly more errors with the desaturated D15 compared with the control group (P < 0.05). The contrast sensitivity for the IDDMs was lower at each spatial frequency compared with the control group, being significantly different from 3 c/deg and above (P < 0.05). A negative correlation was found between HbA1 and contrast sensitivity at 6 and 12 c/deg; as the HbA1 increased the contrast sensitivity decreased (P < 0.05). As the blood glucose level decreased, the colour vision deteriorated (P < 0.05). There was no significant difference between the visual performance of those IDDMs with retinopathy (n = 5) compared to those without.

Intake, digestibility, and ruminal degradability of shredded hay

Thirty-two Outaouais intact male lambs averaging 39.1 kg were assigned randomly to a 2 x 2 factorial arrangement of treatments consisting of two forages and two methods of harvesting to determine intake and digestibility. The four treatments fed during the experiment consisted of alfalfa and timothy hays harvested with either a prototype mat maker or a conventional mower conditioner. Hays were fed for ad libitum intake for the entire experiment, and data on digestibility and intake were collected for 9 d after a 21-d adaptation. Ruminal degradability of DM, N, and ADF of hays was estimated with two fistulated cows using nylon bags incubated up to 96 h. Harvesting with the prototype mat maker compared with the conventional mower generally increased intake and digestibility of alfalfa and timothy hays. Ruminal degradability of DM and the potentially degradable fraction of DM and ADF was higher when hay was harvested with the prototype mat maker than with the conventional mower. The increased digestibility of hay harvested with the prototype mat maker could be explained by the increased digestibility in the rumen because harvesting with the prototype mat maker increased the potentially degradable fraction of DM and ADF. These results suggest that the digestible energy content of hay was increased by shredding.

Performance, carcass and pork characteristics of castrates and gilts self-fed diets differing in protein content and lysine:energy ratio

The effects of five diets, with 12–18% crude protein (CP) and 6.6–10.8 g lysine per MJ digestible energy (DE), on live performance, carcass and meat quality criteria were recorded for 90 pigs in a split-plot design involving male castrates and gilts and three replicates, with three pigs per pen. The five diets, differing in the ratio of barley:soybean meal, were fed as pellets, ad libitum from 25 to 98 kg liveweight. A balanced incomplete block design was used with four additional pens to assess the palatability of the diets offered in pairs sequentially over 10 wk. As expected, castrates had a higher intake (2817 vs. 2580 g d−1) and daily gain (888 vs. 800 g d−1) than gilts and were relatively fatter except when fed the lowest CP diet. While an increase in dietary CP, or lysine:energy ratio, led to significant improvements in growth rate, gain:feed and lean content, there was a concomitant reduction in marbling and sensory appeal. The palatability study suggested that both castrates and gilts tended to favour the intermediate diets (8.8 and 10.1 g lysine per MJ DE) over the others, with a preference for higher CP diets in the early growth period. Estimates of the lysine:DE ratio for maximum live performance indicated that gilts should receive > 10.8 in the pre- − 50 kg period and approximately 10.1 g lysine per MJ DE thereafter. For castrates, the respective ratios were 10.8 and 8.8 g per MJ DE. Split-sex feeding, with gilts receiving about 2% higher dietary protein levels than castrates, was also favoured by the estimates of economic benefits for the producer. Key words: Pigs, lysine, digestible energy, carcass, pork quality

Utilization of grass silage by cattle: effect of supplementation with different sources and amounts of protein

Forty-eight crossbred beef steer calves, initial live weight of 260 kg, were used to examine production responses when grass silage was supplemented with fish meal (FM) or soybean meal (SBM) during a 210-d feeding period. The silage was available on an ad libitum basis either alone or supplemented with 100, 225, 350, or 500 g of FM or 600 g of SBM/d. Increasing levels of FM resulted in a linear increase in live weight gain (P < .001) and gain:feed ratio (P < .001). The FM supplementation had no effect (P = .79) on silage DM intake. The FM supplement increased plasma albumin concentration (P < .05) but did not affect plasma glucose (P > .20) The steers were shipped to market when they had 8 mm of fat over the longissimus muscle as determined by ultrasound. Sensory evaluation of roasts from steers fed 0, 225, 350, or 500 g/d of FM indicated a positive linear (P < .01) increase in flavor and decrease in juiciness as FM level increased. There were no differences (P > .15) in live weight gain, intake, or gain:feed ratio between isonitrogenous supplements of FM and SBM. However, the additional gain resulting from SBM and FM indicated that, on a crude protein basis, SBM was approximately 80% as effective as FM in increasing live weight gain in steers fed grass silage.

Effect of supplementing gilts' diets with different levels of vitamin E and different fats on the humoral and cellular immunity of gilts and their progeny

The effects of supplementing gestation and lactation diets of gilts with different combinations of vitamin E at or above NRC recommended levels (22, 44, or 88 IU/kg during gestation and 55, 110, and 220 IU/kg during lactation) and types of fat (5% added tallow or fish oil or no added fat) on humoral and cellular immunity of gilts and their pigs were evaluated. With only two exceptions, total IgG, IgM, and IgA in colostrum, milk, and plasma of gilts and in plasma of their pigs did not show significant (P > .05) effects, and no interactions between vitamin E and fat supplementation were observed. Cellular immunity was measured as lymphocyte proliferation response to phytohemagglutinin (PHA), concanavalin A (Con A), purified protein derivative of Mycobacterium avium, keyhole limpet hemocyanin, Escherichia coli lipopolysaccharide (LPS), and Salmonella typhimurium LPS. Only the nonspecific mitogens, PHA and Con A, induced proliferation of gilt and pig lymphocytes. Fish oil supplementation in the gilts' diets resulted in lower (P < .01) postpartum PHA response in gilts and slower (P < .05) acquisition of PHA response in newborn pigs compared with groups with added tallow or no added fat. The vitamin E supplementation did not have a significant positive effect on either PHA or Con A response of the gilts. However, the rate of acquisition of PHA response and Con A response in newborn pigs was greater (P < .05) for groups supplemented with 110 and 220 IU/kg of vitamin E than for the group supplemented with 55 IU/kg vitamin E.

The synthesis of oligoribonucleotides containing O6-methylguanosine: the role of conserved guanosine residues in hammerhead ribozyme cleavage

The synthesis is described of oligoribonucleotides containing the modified nucleoside O6-methylguanosine. Solid-phase oligoribonucleotide assembly was carried out by use of 2'-silyl-protected nucleoside phosphoramidites, a new O6-methylguanosine-containing synthon and a mild deprotection method. The O6-methylguanosine-modified oligonucleotides were used in the study of the role of conserved residues G5, G8 and G12 in hammerhead ribozyme cleavage. Hammerheads thus substituted at any of these positions showed an approximately 75-fold reduction in kcat whereas Km was unaffected. Hammerheads with modifications at G5 or G8 showed a significant reduction in magnesium binding affinity whereas modification at G12 had no effect. The results show that the three conserved G residues play crucial but different role sin hammerhead cleavage.

Prehospital cardiac arrest survival and neurologic recovery

Many studies of prehospital defibrillation have been conducted but the effects of airway intervention are unknown and neurologic follow-up has been incomplete. A non-randomized cohort prospective study was conducted to determine the effectiveness of defibrillation in prehospital cardiac arrest. Two ambulance companies in the study area developed a defibrillation protocol and they formed the experimental group. A subgroup of these patients received airway management with an esophageal obturator airway (EOA) or endotracheal intubation (ETT). The control group was composed of patients who suffered a prehospital cardiac arrest and did not receive prehospital defibrillation. All survivors were assessed for residual deficits using the Sickness Impact Profile (SIP) and the Dementia Rating Scale (DRS). A total of 221 patients were studied over a 32-month period. Both the experimental group (N = 161) and the control group (N = 60) were comparable with respect to age, sex distribution, and ambulance response time. Survival to hospital discharge was 2/60 (3.3%) in the control group and 12/161 (6.3%) in the experimental group. This difference is not statistically significant. Survival in the experimental group by airway management technique was basic airway support (3/76 3.9%), EOA (3/67 4.5%), and ETT (6/48 12.5%). The improved effect on survival by ETT management was statistically significant. Survivors had minor differences in memory, work, and recreation as compared to ischemic heart disease patients as measured by the SIP and DRS. No effect of defibrillation was found on survival to hospital discharge. However, endotracheal intubation improved survival in defibrillated patients. Survivors had a good functional outcome.

Predicting outcome after treatment for generalised anxiety disorder

A previous paper, Butler and Anastasiades (Behaviour Research and Therapy 26, 531-534, 1988) presented evidence for three reliable predictors of response to Anxiety Management in patients with generalised anxiety disorder. It was argued there that these reflected severity of anxiety, demoralisation and depression. A second study (Butler, Fennell, Robson & Gelder, Journal of Consulting and Clinical Psychology, 59, 167-175, 1991) has compared two treatments for GAD: Behaviour Therapy and Cognitive Behaviour Therapy. Data from this study is used here to answer two questions: (i) do the same three variables predict outcome in the second study? The answer to this question is 'no'; and (ii) which variables contribute to prediction of outcome when these two treatments are compared? Information presented here suggests that this depends partly on the nature of the treatment given. Outcome after behaviour therapy is predicted by initial levels of anxiety only, but the gains made are also relatively modest. Outcome after cognitive behaviour therapy is predicted by the degree to which ambiguous (external) information is interpreted as threatening. Thus a cognitive variable contributes reliably to the prediction of outcome after a cognitive treatment, but does not predict in the same way to outcome after a behavioural treatment.

Vitamin E and fat supplementation of sows and the effect on tissue vitamin E concentrations in their progeny

A study was conducted to evaluate the effects of supplementing the diets of gestating and lactating sows with 3 levels of vitamin E (22, 44 or 88 IU/kg) and fat (no fat, 5% tallow, or 5% fish oil) on tissue vitamin E concentrations in their progeny. Tissue levels of vitamin E were examined at birth, and then at 14 and 28 d of age in the suckling piglets. Vitamin E concentration in all tissues at birth were very low (hip muscle, neck muscle, lung, brain, heart, kidney < 1.0 microgram/g tissue). Piglet tissue vitamin E levels at birth were influenced by the vitamin E status of the maternal diet during gestation. The piglet tissue concentration of vitamin E increased 2- to 3-fold by 14 d of age. Tocopherol concentrations greater than 3 micrograms/g tissue were found in the liver, lung, spleen, heart and kidney. Tissue vitamin E concentrations of piglets from sows that had received fish oil were lower (significantly in 5 cases: P < 0.05) than piglets from sows receiving tallow or no fat. Tocopherol concentrations in tissues, with the exception of the spleen, increased significantly (P < 0.05) with increased vitamin E in the sows' diet.

The calcium binding proteins parvalbumin and calbindin-D 28K form complementary patterns in the cat superior colliculus

Parvalbumin (PV) and calbindin-D 28K (CaBP) are calcium binding proteins involved in calcium regulation in the brain. In some regions they coexist in the same neuron, while in other regions they are found in different cell types. We have studied the distribution and morphology of PV labeled neurons in the cat superior colliculus (SC) with antibody immunocytochemistry and compared this labeling to that of CaBP. PV neurons were concentrated in a dense tier within the deep superficial gray and upper optic layers. Scattered PV neurons also were found within the deep layers of SC. By contrast, CaBP neurons were concentrated in three tiers: one within the zonal and upper superficial gray layers, a second within the deep optic and upper intermediate gray layers (IGL), and a third within the deep gray layer. The distribution of PV neurons is thus complementary to that of CaBP neurons, with the CaBP cell tiers bordering the dense tier of PV neurons. PV neurons varied in size and morphology. The average diameter of labeled cells was 20 microns, almost twice the size of CaBP neurons. The cells were predominantly round, vertical fusiform, or stellate, and included the very large neurons found scattered in the IGL. Horseradish peroxidase injections into the lateral geniculate nucleus, the lateral posterior nucleus, the opposite superior colliculus, the dorsal lateral pontine gray nucleus, and two descending pathways--the crossed predorsal bundle and the tecto-ponto-bulbar tracts--each labeled SC neurons that were also labeled by PV. A large percentage (84%) of projection neurons contained PV. This result also differs from CaBP neurons in SC, most of which are interneurons. Two antigen double-label experiments did not produce any cells that contained both PV and CaBP. The two calcium binding proteins thus reveal a unique sublaminar organization in SC that consists of alternating small cell interneuron groups and large cell projection neuron groups.

Feed efficiency, carcass characteristics, and sensory quality of lambs, with or without prolific ancestry, fed diets with different protein supplements

Data were collected on 130 intact male lambs fed diets based on roughages supplemented with fish meal, soybean meal, or corn gluten-blood meal and slaughtered at 43 kg live weight. A nonsupplemented group served as a control. The lambs represented Romanov (R), Finnsheep (F), a new breed developed in Canada (DLS), Coopworth (C), and Suffolk (S), three first crosses of DLS with R, F, and Booroola Merino (B), and their backcrosses to DLS. Supplemented lambs consumed 16 to 22% less (P less than .05) silage than control lambs. Average daily gains of lambs fed fish meal (226 g) and corn gluten-blood meal (217 g) were higher and feed conversion ratio (4.99 and 5.11) lower than that of lambs fed soybean meal (189 g and 5.48) or control (186 g and 5.76) diets (P less than .05). The cost of feed per kilogram of gain or per kilogram of lean produced was similar in the four treatments but was between C $.23 and .65 cheaper in the protein-supplemented groups when the number of days to reach slaughter weight was considered. The effect of diet on carcass traits and meat quality were minimal. Meat of lambs fed the three protein supplements was less juicy than that of control lambs. With a few exceptions, most of the significant differences among genetic groups in growth, carcass, and sensory traits were mainly between prolific (R and F) and meat-type breeds (C, S, and DLS). Gain in weight was highest in S lambs (199 g/d), but F and R first crosses were the youngest at slaughter (196 and 198 d). The F lambs had higher dressing and kidney fat percentages than meat-type breeds. The DLS lambs had the largest longissimus muscle area (14.0 cm2), whereas C had the smallest (10.7 cm2). The B crosses had larger longissimus muscle area than R and F crosses. The R lambs had more lean and less fat in the 12th rib, whereas C lambs had the lowest lean and a high bone percentage. The toughest and the most tender roasts were those of R and B crossbred lambs, respectively. Roasts from F lambs had the most intense lamb flavor.

Effect of dietary level of naked oats (Avena nuda) on internal and sensory quality of eggs and on yolk lipid composition

The yolk lipid composition was determined and the sensory and internal quality evaluated for eggs obtained from hens at 8 and 15 m of age from two experiments. In exp. 1, in which naked oats replaced corn and soybean meal at levels of 0–800 g kg−1, there was a marked decrease in Roche yolk color at 8 mo, an increase in egg weight, and at 15 mo and a decrease in yolk flavor intensity with increasing level of oats. In exp. 2, there were four diets (0) a corn-soybean meal control, (876) a soybean-free naked oat alfalfa diet, (874) diet 876 supplemented with lysine and methionine and (691) diet 876 supplemented with canola meal. Haugh units were greater and yolk color less for supplemented naked oat diets versus the control diet. The yolk lipid content of sphingomyelin and sterols were higher than for the control diet. A yolk sulfury aroma was noted at 15 mo. At 8 mo, egg Haugh units were lower for the unsupplemented oat diet relative to the corn-soy diet. There were no other detrimental effects of oat diet on egg sensory quality. Other than a corrigible yolk color effect, egg quality traits do not limit the use of naked oats in poultry layer diets. Key words: Oats (naked), canola, egg internal quality, egg sensory quality, egg lipid composition, laying hen

Parallel pathways of gene regulation: homologous regulators SWI5 and ACE2 differentially control transcription of HO and chitinase

Two independent pathways of transcriptional regulation that show functional homology have been identified in yeast. It has been demonstrated previously that SWI5 encodes a zinc finger DNA-binding protein whose transcription and cellular localization both are cell cycle regulated. We show that ACE2, whose zinc finger region is nearly identical to that of SWI5, shows patterns of cell cycle-regulated transcription and nuclear localization similar to those seen previously for SWI5. Despite their similarities, SWI5 and ACE2 function in separate pathways of transcriptional regulation. SWI5 is a transcriptional activator of the HO endonuclease gene, whereas ACE2 is not. In contrast, ACE2 is a transcriptional activator of the CTS1 gene (which encodes chitinase), whereas SWI5 is not. An additional parallel between the SWI5/HO pathway and the ACE2/CTS1 pathway is that HO and CTS1 both are cell cycle regulated in the same way, and HO and CTS1 both require the SWI4 and SWI6 transcriptional activators. Overproduction of either SWI5 or ACE2 permits transcriptional activation of the target gene from the other pathway, suggesting that the DNA-binding proteins are capable of binding in vivo to promoters that they do not usually activate. Chimeric SWI5/ACE2 protein fusion experiments suggest that promoter specificity resides in a domain distinct from the zinc finger domain.

The effect of frequency of feeding and supplementation with sucrose on ruminal fermentation of alfalfa silage given ad libitum or restricted to sheep

Eight ruminally cannulated wethers were used in a factorial trial to examine the effect of frequency of feeding alfalfa silage and sucrose supplementation on voluntary intake, digestibility, rumen fermentation and rate and extent of digestion in and passage from the rumen. When diets were fed ad libitum, frequency of feeding had no effect on voluntary intake, apparent digestibility or the postfeeding concentrations of rumen ammonia N, volatile fatty acids (VFA) and pH. Similarly, VFA ratios and fluid kinetics in the rumen were unaffected. Supplementation with sucrose reduced ruminal concentrations of ammonia N at the higher level of feeding but failed to influence any other measured parameters. When intake was restricted (18 g DM kg−1 body weight), increased feeding frequency reduced the post-feeding ruminal ammonia peak and reduced the post-feeding decline in pH; however, sucrose supplementation had no effect. Kinetics of the liquid phase in the rumen, particulate rate of passage and rate of digestion were not affected by feeding frequency or sucrose supplementation. It was concluded that effects observed at a restricted feeding level may not be apparent when feed is available ad libitum and vice versa. Key words: Sucrose, feeding frequency, alfalfa, silage, sheep

Elimination of mycoplasmas from cell cultures by a novel soft agar technique

Mycoplasmal infection of cell cultures remains a significant threat to diagnostic and research procedures. In certain defined situations, curing of mycoplasmal infected cultures is a reasonable exercise. Four methods of curing were compared: treatment with BM-cycline, 5 bromouracil, use of specific antisera and treatment of infected cells suspended in soft agar with antibiotics. Antisera treatments were of low efficiency of curing: 50%. None of nine infected cell lines treated with 5-bromouracil were consistently cured of mycoplasmas. The use of BM-cycline was effective for some, but not all lines and required long periods of treatment, 12-21 days. 35 naturally or deliberately infected cultures were treated in soft agar a total of 119 times. This procedure which consisted of suspending infected cultures in soft agar containing appropriate antibiotics resulted in successful mycoplasmal elimination 118/119 times. This soft agar technique took 1-3 days. In separate studies, it was shown that certain Mycoplasma fermentans strains were resisted to this and other curing methods. This may be due to their intracellular location. Such strains may be more amenable to antibiotics that penetrate mammalian cells. It is concluded that the soft agar technique is a rapid, efficient and reliable method to eliminate cell culture mycoplasmas.

Comparison of behavior therapy and cognitive behavior therapy in the treatment of generalized anxiety disorder

In a controlled clinical trial, 57 Ss meeting DSM-III-R criteria for generalized anxiety disorder, and fulfilling an additional severity criterion, were randomly allocated to cognitive behavior therapy (CBT), behavior therapy (BT), or a waiting-list control group. Individual treatment lasted 4-12 sessions; independent assessments were made before treatment, after treatment, and 6 months later, and additional follow-up data were collected after an interval of approximately 18 months. Results show a clear advantage for CBT over BT. A consistent pattern of change favoring CBT was evident in measures of anxiety, depression, and cognition. Ss were lost from the BT group, but there was no attrition from the CBT group. Treatment integrity was double-checked in England and in Holland, and special efforts were made to reduce error variance. Possible explanations for the superiority of CBT are discussed.