Prospects for the genetic manipulation of dairy cattle: opportunities beyond BST

The dairy industry, with regulatory approvals of recombinant chymosin and bovine somatotropin (BST), has been at the forefront of food and agricultural biotechnology. The commercial fate of these products is one of several factors that may affect the success of future genetic manipulations in dairy cattle and dairy products. Other factors include technical and reproductive constraints in cattle and the cost of producing transgenic cattle. Early applications of genetic manipulation in cattle, for reasons of cost recoupment, may favor production of heterologous proteins in milk for pharmaceutical and medical use. Such applications could benefit genetic modification of milk and milk proteins for food use by providing advance knowledge and experience in mammalian protein expression. Other research opportunity areas that could affect prospects for genetic manipulation of dairy cattle include genome mapping, metabolic pathways, growth and development, and cattle/microbe interactions.

Caloundrin B and Funiculatin A: New Polypropionates From Siphonariid Limpets

Two new polypropionates, caloundrin B (11), systematic name (1″R,2R,3″R,4R,5S,5″R,6S,-7″R,8″S,9″S,10″R)-2-(6′-ethyl-3′,5′-dimethyl-4′-oxopyran-2′-yl)-6-(5″-ethyl-7″-hydroxy-8″,9″,10″-trimethyl-2″,4″,6″-trioxatricyclo[3.3.1.13,7]dec-3″-yl)-5-hydroxy-4-methylheptan-3-one, and funiculatin A (12), systematic name (2ξ,1′S,4R,5′S,6′S)-2-(1′-ethyl-4′,6′,8′-trimethyl-2𔈀,9′-dioxabicyclo[3.3.1]nona-3′,7′-dien-3′-yl)-4,6-dimethylnon-6-en-3-one, have been isolated from Siphonaria zelandica and S. funiculata respectively. The structures of the new compounds were deduced by two-dimensional n.m.r. spectroscopy, particularly long-range 13C- 1H correlation spectroscopy (HMBC), by biosynthetic reasoning and by comparison with the known polypropionates denticulatin A (5), siphonarin B (8), muamvatin (9) and baconipyrone C (14). Information about the relative stereochemistry of the tricyclic ring system of (11) and the bicyclic ring system of (12) was deduced from coupling constant values, and by n.O.e. difference and NOESY experiments, and was confirmed by molecular modelling studies. The relative stereochemistry of the side chains and the absolute stereochemistry were inferred from biosynthetic comparison with the above known polypropionates, and by correlation of funiculatin A with denticulatin A (5) of known absolute stereochemistry. The stereochemistry at C10 of funiculatin A (position 2 of the non-6-en-3-one chain) could not be unambiguously determined. A third new polypropionate funiculatin B, epimeric with funiculatin A at C10, was isolated and partially characterized.

Expression of a foreign gene in Chlamydomonas reinhardtii

Genomic transformation of Chlamydomonas reinhardtii exposed to glass-bead abrasion was accomplished with a chimeric neomycin phosphotransferaseII (NPTII)-encoding gene (nos::npt) flanked by the nopaline synthase promoter and polyadenylation sequences obtained from the Ti plasmid of Agrobacterium tumefaciens. These sequences were in a plasmid (pGA482) which also contained gene nit1 encoding nitrate reductase of C. reinhardtii. Transformants were selected by their ability to grow on medium containing nitrate, and 52% of these was also resistant to kanamycin. Evidence for nos::npt expression includes: (1) hybridization with probes specific for npt, (2) demonstration of NPTII activity after electrophoresis of extracts, and (3) chromatographic identification of the reaction product of NPTII, kanamycin phosphate. The highly biased codon usage in Chlamydomonas does not preclude expression.

Norepinephrine inhibits rat pre-adipocyte proliferation

Hormonal and neural status are major determinants for cellular growth. The purpose of this study was to assess the influence of the adrenergic hormones on pre-adipocyte growth in primary cell culture. Stromal-vascular cells were obtained from the inguinal pad of young rats and grown in culture for two weeks. Cells were exposed to norepinephrine (NE) during the proliferative phase of growth, labelled by [3H]-thymidine incorporation and then placed on a differentiation promoting medium. Adipocytes and stromal cells were separated using a density gradient, and [3H]-thymidine content was determined for both cell types. NE reduced [3H]-thymidine uptake indicating a reduction in pre-adipocyte proliferation. NE-induced inhibition of pre-adipocyte growth was blocked by the presence of propranolol, whereas phenoxybenzamine had no effect, thereby suggesting that NE-inhibition is through beta-adrenoceptors. Pre-adipocytes were treated with NE for varying lengths of time to investigate whether cells were desensitized to chronic beta-adrenergic stimulation. In addition, adenosine deaminase (ADA) was also applied to eliminate adenosine which may accumulate during NE stimulation. Neither the duration of NE exposure nor ADA treatment affected adrenergic control of adipocyte growth. These studies indicate that NE reduces pre-adipocyte proliferation and therefore may be an important negative regulatory component of adipocyte growth.

Local regeneration in the retina of the goldfish

We have studied regeneration of the retina in the goldfish as a model of regenerative neurogenesis in the central nervous system. Using a transscleral surgical approach, we excised small patches of retina that were replaced over several weeks by regeneration. Lesioned retinas from three groups of animals were studied to characterize, respectively, the qualitative changes of the retina and surrounding tissues during regeneration, the concomitant cellular proliferation, and the quantitative relationship between regenerated and intact retina. The qualitative and quantitative analyses were done on retinas prepared using standard methods for light microscopy. The planimetric density of regenerated and intact retinal neurons was computed in a group of animals in which the normal planimetric density ranged from high to low. Cell proliferation was investigated by making intraocular injections of 5-bromo-2'-deoxyuridine (BUdr) at various survival times to label proliferating cells and processing retinal sections for BUdr immunocytochemistry. The qualitative analysis showed that the surgery created a gap in the existing retina that was replaced with new retina over the subsequent weeks. The BUdr-labeling experiments demonstrated that the excised retina was replaced by regeneration of new neurons. Neuroepithial-like cells clustered on the wound margin and migrated centripetally, appositionally adding new retina to the old. The quantitative analysis showed that the planimetric density of the regenerated neurons approximated that of the intact ones.

Evaluation of a simple method for the measurement of cytidine deaminase in serum and comparison with a reference method

This study was designed to evaluate a cytidine deaminase (CD) assay modified to allow results to be achieved within one working day. Inter-batch variation for samples of mean (SD) CD activity, 10.2 (1.0) units, 17.5 (1.2) units and 31.7 (1.7) units were, 9.8%, 6.9% and 5.4% respectively (n = 26). The reference range (3.2-13.2 U) was similar in males and females and was independent of age. There was close correlation with a reference method (r = 0.96). The mean difference between methods was 2.7 U and the limits of agreement were -1.7 to 7.1 U. The results indicate that the short assay technique can produce results that are sufficiently accurate and precise to be clinically useful.

An update of the enzymology and regulation of sphingomyelin metabolism

Sphingomyelin is found in plasma membranes and related organelles (such as endocytic vesicles and lysosomes) of all tissues, as well as in lipoproteins. Abnormalities in sphingomyelin metabolism have been associated with atherosclerosis, cancer and genetically transmitted diseases; however, except for Niemann-Pick disease, little is known about the mechanism for these disorders. Sphingomyelin biosynthesis de novo involves ceramide formation from serine and two mol of fatty acyl-CoA followed by addition of the phosphocholine headgroup. The headgroup appears to come from phosphatidylcholine, but other sources have not been ruled out. Factors that influence the rate of sphingomyelin synthesis include the availability of serine and palmitic acid, plus the relative activities of key enzymes of this pathway. Sphingomyelin turnover involves removal of the headgroup and amide-linked fatty acid by sphingomyelinases and ceramidases, respectively, which have been found in both lysosomes (with acidic pH optima) and plasma membranes (with neutral to alkaline pH optima). The enzymes of sphingomyelin turnover release ceramide and free sphingosine from endogenous substrates, which may have implications for the participation of a sphingomyelin/sphingosine cycle as another 'lipid second messenger' system.

Sera from pigs infected with Sarcocystis suicanis and cachectin decrease preadipocyte differentiation in primary cell culture

The macrophage-secreted hormone cachectin depressed lipoprotein lipase activity and lipogenic enzymes in adipose cells. Cachectin reduced differentiation of preadipocytes in cultures of stromal-vascular cells from rat adipose tissue. Differentiation was measured by two methods of estimating lipid accumulation. Adipocytes were separated from the stromal-vascular cells by centrifugation and staining (oil red 0) for intracellular lipid. Lipolytic activity was measured by using esterase histochemistry. Sera from pigs that were infected with Sarcocystis suicanis showed cachectin-like activity compared with sera collected from the same animals before infection. Cachectin and sera collected from infected animals specifically decreased fat cell number without decreasing the stromal-vascular cell number.

Serum cytidine deaminase levels after withdrawal of non-steroidal anti-inflammatory treatment in rheumatoid arthritis

Increases in joint inflammation in nine patients with rheumatoid arthritis were provoked by withdrawal of their non-steroidal anti-inflammatory drugs. Pain score, duration of morning stiffness, Ritchie articular index score, and the number of analgesic tablets consumed reached peaks after five, three, five, and five days respectively compared with values during six days of normal treatment. Changes in serum cytidine deaminase (believed to reflect polymorph turnover in inflamed joints) showed a different pattern, with a sharp peak after two days and a subsequent trough. Possible mechanisms for these differences are discussed.

Influence of manure gases on puberty in gilts

To determine whether manure gases can influence onset of puberty in gilts, 42 crossbred gilts were reared from 10 to 40 wk of age on concrete slats over a 1.22-m deep pit that was drained and refilled with clean water biweekly (clean group). Forty-one gilts were reared over a similar type pit where manure was allowed to accumulate (control group). Treatments were in two separate rooms of the same building with similar feeding, water, floor space, lighting and room temperature. Ventilation fans with timer controls in each room were set so fans in the clean environment ran twice as long as fans in the control environment. Aerial concentrations of ammonia in the control room were fourfold higher than in the clean room (21 vs 5 ppm), while aerial concentrations of hydrogen sulfide were similar. Average daily gain and feed efficiency were similar for both groups [.69 vs .72 kg/d (P = .31) and 1.61 vs 1.54 kg feed/kg gain (P = .52)]. From 20 to 40 wk of age, all gilts were exposed to a mature boar three times weekly, utilizing four boars in rotation. Blood samples were collected weekly from each gilt by venipuncture and analyzed for progesterone to establish time of first ovulation. A greater proportion of gilts in the clean group attained puberty by 24 to 26 wk (P less than .05) and 27 to 29 wk of age (P less than .10) compared with the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

Novel Actinomycete Isolated from Bulking Industrial Sludge

A novel actinomycete was the predominant filamentous microorganism in bulking activated sludge in a bench-scale reactor treating coke plant wastewater. The bacterium was isolated and identified as an actinomycete that is biochemically and morphologically similar to Amycolatopsis orientalis ; however, a lack of DNA homology excludes true relatedness. At present, the isolate (NRRL B 16216) cannot be assigned to the recognized taxa of actinomycetes.

Physical properties of five grain dust types

Physical properties of grain dust derived from five grain types (soybean, rice, corn, wheat, and sorghum) were measured and reported. The grain dusts were obtained from dust collection systems of terminal grain handling facilities and were assumed to be representative of grain dust generated during the handling process. The physical properties reported were as follows: particle size distributions and surface area measurements using a Coulter Counter Model TAII; percent dust fractions less than 100 micron of whole dust; bulk density; particle density; and ash content.

Legal and regulatory aspects of genetically engineered animals

The commercialization of genetically engineered food animals will pose a number of legal and regulatory questions. These may be grouped into questions of process and questions of products. The process of animal genetic engineering with artificially constructed vectors will probably be regulated in much the same manner as other veterinary procedures. There may be some discussion, however, as to whether animal drug or animal biologic regulations are more applicable. The products of animal genetic engineering, i.e., transgenic food animals and food products made from them, also raise important questions about product safety and identity. These include whether and how genetically engineered food animals will be subject to federal inspection for wholesomeness, whether artificial vectors, foreign genes, or gene products will adulterate recipient animal tissues, and how food products made from such animals will be labeled. Prior federal experience with the inspection of interspecific hybrids of cattle and buffalo provides a useful basis for further policy developments in the inspection and labeling of genetically engineered food animals. In particular, the inspection of cattle/buffalo hybrids has established a phenotypic (based on appearance) criterion for deciding how novel food animals should be inspected. As the genetic engineering of food animals on a production basis draws nearer, it may be necessary to supplement the phenotypic criterion with genetic (based on pedigree) criteria to assure that the essential characteristics of animals slaughtered under current food statutes are maintained.

Cytidine deaminase activity as a measure of acute inflammation in rheumatoid arthritis

Cytidine deaminase (CD), a cytoplasmic enzyme, is thought to leak out of damaged cells and can be measured in fluids by a simple biochemical assay. This study has shown that serum CD activity is raised in rheumatoid arthritis (RA) compared with osteoarthritis (OA). Synovial fluid (SF) CD activity was always less than the corresponding serum activity (mean SF/serum ratio = 0.6) in OA but up to 22 times greater than the corresponding serum activity in RA (mean SF/serum ratio = 13.1), suggesting CD production in inflammatory joints. Evidence to support the SF neutrophil as a cell of CD origin is provided by the CD gradient running from cells to SF to synovium. The close correlation between SF CD activity and neutrophil count (r = 0.93) indicates that SF CD activity is an accurate measure of acute synovial inflammation. Weak correlation of serum CD activity with erythrocyte sedimentation rate (ESR) (r = 0.44) and C-reactive protein (CRP) (r = 0.49) implies that CD estimations supply different though related information about rheumatoid disease activity. We suggest that CD released from damaged neutrophils diffuses from all inflamed joints into the blood, so that serum CD activity may provide an integrated measure of joint inflammation more specific than traditional measures such as the ESR.

The estimation of serum guanosine deaminase activity in liver disease

An assay for the estimation of guanosine deaminase is described. The method employs guanosine as substrate and after incubation of serum and substrate at 22 degrees C for 18 h the ammonia liberated is estimated using the Berthelot reaction. Absorbance is measured as 625 nm and the catalytic activity read from a standard curve obtained using ammonia standards. The method provides reproducible measurements of serum guanosine deaminase. The results obtained using 'normal' sera have been used to calculate the 'normal range' for the enzyme in serum. Preliminary results suggest that guanosine deaminase is increased in hepatitis and in patients with liver metastases but normal in all other liver diseases including cirrhosis and obstructive jaundice.

Serum deoxycytidylate deaminase as an index of high-risk pregnancy

Serum deoxycytidylate deaminase (EC 3.5.4.12, dCMP deaminase) activity was routinely estimated over 7 years in 2460 pregnancies. The results confirm that elevated dCMP deaminase activity (greater than 4.8 units) is associated with the development of pre-eclampsia but not with essential hypertension in pregnancy; a high rising level can precede eclampsia. Elevated enzyme activity was also found in women who developed jaundice in pregnancy and in some with apparently normal pregnancies. An unexpected finding was that these so called 'false positive' high levels were associated with all the unexplained intrauterine fetal deaths that occurred later in pregnancy. Although elevated dCMP deaminase levels may be associated with a normal outcome, persisting high levels indicate the need for careful monitoring of fetal well being and, in the presence of any other sign of placental insufficiency, delivery should be expedited.

Activity of serum cytidine deaminase during pregnancy

A simple and reliable method for the estimation of cytidine deaminase (cytidine aminohydrolase; EC 3.5.4.5) activity in pregnancy serum is described. This enzyme does not require magnesium for activation and is also more stable than deoxycytidylate deaminase (dCMP deaminase, dCMP aminohydrolase; EC 3.5.4.12). There was excellent correlation between the two enzymes (r = 0.92). Both enzymes showed increased activity in abnormal pregnancy. Both enzymes activities were found to be similar in 1305 maternal serum samples and therefore due to the simplicity of cytidine deaminase estimation it is recommended for the screening of large numbers of antenatal sera for abnormal pregnancies.

Biophysical cytochemical investigations of intracellular heparin in neoplastic mast cells

The thermodynamic binding parameters for intracellular heparin-acridine orange (AO) complexes were determined for Furth murine mastocytoma cells and were found to agree with 1) results from binding studies on heparin-AO complexes in solution, and 2) with biochemical analyses of the cells. The cells exhibited cooperative binding with a binding constant of 1.18 x 10(6) M-1. The cooperative binding constant of heparin-AO in 1 mM buffer was found to be 1.13 x 10(6) M-1. The addition of 1 mM NaCl to heparin-AO system in vitro detectably decreased the cooperative binding constant. Low ionic strength is the only condition in solution under which the cell and solution binding constants are equal. The cells have an average of 1.2 x 10(-14) mol of AO binding sites per cell. Using the biochemically measured heparin content per cell and the amount of AO bound by heparin in solution, 8 x 10(15) mol of sites/cell can be attributed to heparin. The remaining cellular binding sites (4 x 10(-15) mol of sites per cell) are essentially all accounted for by AO binding to DNA, the amount of which is calculated from its previously determined thermodynamic binding parameters. A theoretical isotherm, calculated from the binding parameters of both heparin-AO in solution and DNA-AO complexes in situ, agreed closely with the isotherm experimentally determined for the Furth mastocytoma cells. Ligand-binding analysis yields a binding constant, which may aid in identification of cellular bipolymers, and the number of ligand binding sites per cell. The latter is a measure of the amount of a given intracellular biopolymer present.

Obliteration of the ductus reuniens

The ductus reuniens was successfully obliterated in 52 guinea pig ears. Histopathological study showed that a majority of these specimens demonstrated cochlear hydrops, saccular collapse and normal utricle. These results support the theory of longitudinal flow of endolymph from the cochlea toward the endolymphatic sac via the ductus reuniens and saccule. A major source of endolymph in the saccule appears to be the scala media. In another set of 11 animals in which the ductus reuniens was first obstructed and two months later the endolymphatic duct was blocked, endolymphatic hydrops was shown in the cochleae, saccules, and utricles of all but one. The evidence suggests that cochlear hydrops was caused by obliteration of the ductus reuniens, and the saccular and utricular hydrops occurred subsequently as the result of blockage of the endolymphatic duct. Remnants of otolithic membrane which were attached to the distended saccular wall indicate that the membrane which had collapsed onto the macula after obliteration of the ductus reuniens is capable of subsequent distension. This experiment supports the concept of endolymph flow from the utricle and canals toward the endolymphatic sac. A blocked cutus reuniens might also explain the pathophysiological basis for the auditory form of Meniere's disease.

Stapedectomy. Postmortem findings

Histological studies were made of 16 temporal bones of 13 subjects who had stapedectomy operations. Photographs of the prostheses in situ are a special feature of the studies. It was found that prostheses which overlap the margins of the oval window cause incomplete closure of the air-bone gaps. Fibrous adhesions were a common consequence of trauma to the mucous membrane of the middle ear. Gelfoam implantation promotes the formation of thin oval window membranes which tend to bulge out of the oval window. Most incudes show small areas of cortical bone resorption. In at least half the cases the surgical technique of stapedectomy, as judged from these studies, was less than ideal. Surgeons who perform stapedectomy should be cognizant of the relevant surgical pathology and adopt methods which will optimize functional results and minimize complications.

Serum deoxycytidylate deaminase activity after myocardial infarction

The activity of serum deoxycytidylate deaminase, not hitherto reported to increase after myocardial infarction, has been investigated and the results have been related to other cardiac enzymes, including the MB fraction of creatine phosphokinase. Deoxycytidylate deaminase was found to increase to maximum activity on the third day after infarction. It may therefore be added to the list of 'cardiac enzymes.