Inhibition of the basal and oestradiol-stimulated mitotic activity of primary spermatogonia by melatonin in the testis of the frog,Rana esculenta,in vivo and in vitro

Melatonin has a direct inhibitory effect on the basal and oestradiol-stimulated mitotic activity of primary spermatogonia in the testis of the frog, Rana esculenta. In this study oestradiol was used to induce spermatogonial proliferation to verify the anti-proliferative effect of melatonin. The colchicine metaphase arrest technique was used. The results obtained from in vivo experiments confirm that oestradiol increases the mitotic index of primary spermatogonia and, for the first time, indicate that melatonin has an inhibitory role on the proliferation of primary spermatogonia in the frog testis. Similar results were obtained from testes of melatonin-injected frogs that were exposed to oestradiol in vitro; in fact spermatogonia were unresponsive to hormonal stimulation. In addition, in short-term cultured testes, melatonin (at physiological concentration) interferes with the effects of oestradiol on spermatogonial proliferation, supporting the hypothesis that melatonin exerts the inhibitory effect directly via its local action on the frog gonads. Morphological observation after in vivo or in vitro melatonin treatments indicates that Leydig cells display degenerative features, whereas in adjacent germinal tubules, Sertoli cells show heterochromatic nuclei. These results indicate that melatonin may act on Leydig cells and confirm that there is a paracrine interaction between interstitial and germinal compartments. The results of the present study indicate, for the first time, that melatonin may be directly involved in the inhibitory control of spermatogonial proliferation in the testis of the frog, R. esculenta.     

Expression of c-Kit receptor mRNA and protein in the developing, adult and irradiated rodent testis

Germ cell proliferation, migration and survival during all stages of spermatogenesis are affected by stem cell factor signalling through the c-Kit receptor, the expression and function of which are vital for normal male reproductive function. The present study comprehensively describes the c-Kit mRNA and protein cellular expression profiles in germ cells of the postnatal and adult rodent testis, revealing their significant elevation in synthesis at the onset of spermatogenesis. Real-time PCR analysis for both mice and rats matched the cellular mRNA expression profile where examined. Localization studies in normal mouse testes indicated that both c-Kit mRNA and protein are first detectable in differentiating spermatogonia. In addition, all spermatogonia isolated from 8-day-old mice displayed detectable c-Kit mRNA, but 30-50% of these lacked protein expression. The c-Kit mRNA and protein profile in normal rat testes indicated expression in gonocytes, in addition to differentiating spermatogonia. However, in the irradiated adult rat testes, in which undifferentiated spermatogonia are the only germ cell type, mRNA was also detected in the absence of protein. This persisted at 3 days and 1 and 2 weeks following treatment with gonadotrophin-releasing hormone (GnRH) antagonist to stimulate spermatogenesis recovery. By 4 weeks of GnRH antagonist treatment, accompanying the emergence of differentiating spermatogonia, both mRNA and protein were detected. Based on these observations, we propose that c-Kit mRNA and protein synthesis are regulated separately, possibly by influences linked to testis maturation and circulating hormone levels.     

Production of inhibin A not B in rams: changes in plasma inhibin A during testis growth,and expression of inhibin/activin subunit mRNA and protein in adult testis

Previous studies have shown that changes in the plasma concentrations of immunoreactive inhibin measured by radioimmunoassay occur in parallel with growth and regression of the testes during a reproductive cycle in adult Soay rams induced by exposure to an artificial lighting regimen of alternating 16 week periods of long days and short days. With the development of new two-site ELISAs for sheep inhibin A and inhibin B, we have re-examined the relationship between FSH and dimeric, biologically active inhibin in the reproductive cycle in adult Soay rams. No signal was generated by sheep testicular extract, ram or ewe plasma, or sheep ovarian follicular fluid in the inhibin B ELISA. In contrast, ram plasma contained significant activity in the inhibin A ELISA, which diluted in parallel to the inhibin A standard, and was abolished by preincubation of ram plasma with monoclonal antibodies specific for the betaA, but not the betaB, subunit. These results indicate that the ram is the first adult male mammalian species identified to date in which the testes produce and secrete dimeric inhibin A and not inhibin B. Northern blot analysis and immunocytochemistry confirmed the presence of alpha, betaA and betaB inhibin/activin subunit mRNA and protein in the testes of adult rams. Changes in plasma inhibin A concentrations occurred in parallel with the growth and regression of the testes during the long day: short day: long day lighting regimen in adult Soay rams, confirming our previous observations with immunoreactive inhibin. During the growth phase of the testes in the first 8 weeks of exposure to short days there was a positive correlation between plasma FSH and inhibin A concentrations, indicating that during this phase the secretion of inhibin A is stimulated by FSH and that inhibin A did not act as a negative feedback hormone on FSH secretion. From week 8.5 to week 16.0 of exposure to short days, there was a negative correlation between FSH and testosterone concentrations, but not inhibin, indicating that when inhibin concentrations are high, testosterone acts as the negative regulator of FSH secretion. Thus, in intact adult rams, when the testes are fully active it appears that inhibin A may sensitize the pituitary to the negative feedback effects of testosterone, at which time they act synergistically to maintain plasma concentrations of FSH.     

Relationship between seasonal changes in spermatogenesis in the juvenile ostrich (Stuthio camelus) and the presence of the LH receptor and 3beta-hydroxysteroid dehydrogenase

The immunohistochemical localization of the LH receptor and 3beta-hydroxysteroid dehydrogenase (3beta-HSD) was studied in the testis of the juvenile ostrich (Stuthio camelus) throughout a 1 year period. Spermatogenic activity of juvenile birds changed throughout the year, as has been reported previously for sexually mature birds. During the active stage of the testicular cycle, from September to January, spermatogenesis progressed up to the stage of formation of spermatozoa, although spermatozoa could not be detected in the epididymis. Leydig cells stained intensely with antibodies against the LH receptor and 3beta-HSD during the quiescent, recrudescent and active phases of the testicular cycle. During the regressive phase, there was a slight decrease in immunostaining for 3beta-HSD in these cells. These results indicate that Leydig cells in the testis of the juvenile ostrich are able to respond to LH and are capable of steroid synthesis. Furthermore, in juvenile (prepubertal) ostriches, spermatogeneic activity can be observed and, as in mature birds, spermatogenesis undergoes seasonal changes.     

Mechanical properties of white and green asparagus: changes related to modifications of cell wall components

The changes of texture that take place in white and green asparagus during storage and cooking are, in large part, determined by the composition and structure of the cell walls. Several instrumental methods have been applied to three sections of the spears to investigate the physico‐chemical properties that contribute to the values of texture. Cutting the spears with a razor blade is the most appropriate method for quantifying and comparing the texture of white and green asparagus and, among the different parameters that can be calculated from the curves registered during asparagus cutting, strength and toughness have been used for determining changes of texture. Post‐harvest storage caused an increase of texture mainly located in the lower portions of the white spears. The process of toughening also affected the lower section of the green spears, but to a lesser extent. Cooking resulted in a softening, mostly in the apical section of the stem. Additional information about the physico‐chemical properties of different plant tissues has been obtained by applying a tensile test to the internal and external tissues separated from asparagus sections. Copyright © 2004 Society of Chemical Industry     

Effects of ACTH and expression of the melanocortin-2 receptor in the neonatal mouse testis

ACTH has been shown to stimulate androgen production by the fetal/neonatal mouse testis through the melanocortin type 2 receptor (MC2R). This study was designed to localize the expression of MC2R in the neonatal mouse testis and characterize the effects of ACTH on testicular androgen production. Using immunohistochemistry, MC2R was localized to the fetal-type Leydig cell population of the neonatal testis. ACTH caused a time-dependent increase in cyclic AMP (cAMP) and testosterone production by isolated cells with an increase in cAMP apparent in < 3 min. There was no additive effect of maximally stimulating doses of ACTH and human chorionic gonadotropin (hCG). Androgen production in response to ACTH and hCG was reduced by UO126 and dexamethasone, which are the inhibitors of ERK1/2 and phospholipase A2 respectively. Expression of mRNA encoding StAR was increased fourfold by both ACTH and hCG, although expression of mRNA encoding for steroidogenic enzymes was not markedly affected. The potency of N-terminal fragments of ACTH to stimulate androgen production was similar to that seen previously in the adrenal. Data indicate that both LH and ACTH, acting through their respective receptors, stimulate steroidogenesis by fetal-type Leydig cells via arachidonic acid, protein kinase A, and ERK1/2 activation of StAR.     

The morphological changes produced in cauliflower stems during pickling, and their relationship to texture parameters

Summary. The changes in morphology and texture which occur during the pickling of cauliflower have been studied using the electron microscope and Instron Universal testing rig.
It has been shown that the marked changes in the texture parameters, hardness, elasticity and cohesion, during the initial 24 hr in brine, correlate with plasmolysis of the tissue and re-organization of cell wall materials. At the end of the 1st week in brine, with the disruption of the protoplast, the only intact organelles were the spherosomes. the cell walls became extremely thin in the pit field regions, and it was to these areas that the spherosomes tended to migrate. the disruption of the spherosomes, during the 4th week in brine, with the possible release of hydrolytic enzymes may have contributed to the further weakening of the cell wall.
The use of electron histochemical stains has permitted the demonstration of the gradual degradation of pectic substances, resulting in enlarged intercellular spaces and a decrease in tissue cohesion. By staining neutral polysaccharides, it has been shown that the cell wall materials are not degraded to a marked extent and hence would add little to the sugars available for bacterial fermentation.
The increase in crispness, said to arise from freshening and acidification, is not just a simple recovery in turgor pressure, since the protoplast plasmalemma quickly loses its semi-permeable characteristics and is later destroyed. However, an enhancement of elasticity and tissue cohesion has been demonstrated by using freshening solutions containing 2500 ppm calcium.     

Mixed proteinaceous emulsifiers: review of competitive protein adsorption and the relationship to food colloid stabilization

The importance of competitive protein adsorption in the formation and stabilization of food emulsions and foams is examined from both experimental and theoretical standpoints. Issues and problems relevant to mixed protein systems are discussed: the relationship to synthetic polymer adsorption, the effects of labelling and modification, interactions with polysaccharides and lipids and the topics of irreversibility and polydispersity. Information on mixtures of (i) blood plasma proteins and (ii) milk proteins is reviewed in detail. Surface hydrophobicity is discussed in relation to protein surface-activity and resulting emulsifying and foaming capacity. Surface rheological behaviour of adsorbed protein films is discussed in relation to emulsion and foam stability.     

The relationship of sarcoplasmic and myofibrillar protein solubility to colour and water-holding capacity in porcine longissimus muscle

In order to investigate the relationship of sarcoplasmic and myofibrillar protein solubility to colour and water-holding capacity (WHC) in pork, 60 loins were selected to represent the quality classes: PSE (pale, soft, exudative), RSE (reddish-pink, soft, exudative), RFN (reddish-pink, firm, non-exudative) and DFD (dark, firm, dry). PSE samples exhibited lower (p<0.05) protein solubility (sarcoplasmic, myofibrillar and total) compared to the other quality classes. RSE samples exhibited lower (p<0.05) sarcoplasmic protein solubility compared to DFD samples. RSE, RFN and DFD samples had similar myofibrillar and total protein solubilities. Sarcoplasmic protein solubility explained 71% of the variation in lightness with a linear decrease in L* value. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) gels of the sarcoplasmic and myofibrillar samples distinctly showed the association of some sarcoplasmic proteins with the myofibrillar protein fractions in PSE and RSE samples. The sarcoplasmic proteins which precipitated were phosphorylase, creatine kinase, triose phosphate isomerase and myokinase for PSE and phosphorylase for RSE samples. Pork colour is highly correlated with precipitation of sarcoplasmic proteins while WHC is affected by denaturation of myofibrillar proteins (PSE samples) and lower ultimate pH (PSE and RSE samples).     

Comparison of androgen receptor and oestrogen receptor beta immunoexpression in the testes of the common marmoset (Callithrix jacchus) from birth to adulthood: low androgen receptor immunoexpression in Sertoli cells during the neonatal increase in testosterone concentrations

The aims of this study were: (i) to investigate the cellular immunoexpression of androgen receptor and oestrogen receptor beta in the testes of the common marmoset (Callithrix jacchus) during neonatal life compared with their expression at later ages; (ii) to establish whether neonatal marmoset Sertoli cells are targets for androgens or oestrogens or both; and (iii) to investigate the relationship between neonatal plasma testosterone concentrations and androgen receptor immunoexpression by abolishing the neonatal testosterone surge with a potent GnRH antagonist. Androgen receptor and oestrogen receptor beta immunoexpression were evaluated in neonatal animals aged 1-4 days, 4 weeks and 6 weeks, and compared with immunoexpression in animals aged 18-22 weeks (early infancy), 35 weeks (late infancy), 58-62 weeks (late pubertal) and > 100 weeks (adult). Immunoexpression of androgen receptor in the reproductive tract was also evaluated at each age. Sertoli cell immunoexpression of androgen receptor was weak or absent in neonatal animals, but increased substantially in infant animals, reaching adult levels by the end of infancy. In contrast, immunoexpression of androgen receptor during the neonatal period was strong in testicular interstitial cells and very strong in epithelial cell nuclei throughout the reproductive tract, and did not change greatly with age in these cells or tissues. Similarly, immunoexpression of oestrogen receptor beta was prominent in many Sertoli cells and in the germ cells of neonatal animals, and was relatively constant throughout life. Weak immunoexpression of androgen receptor in neonatal Sertoli cells was associated with high plasma testosterone concentrations (2.7-5.5 ng ml(-1)), whereas strong Sertoli cell immunoexpression was associated with baseline (approximately 0.12 ng ml(-1)) testosterone concentrations in infant animals and with > 10 ng ml(-1) in late pubertal and adult animals. Immunoexpression of androgen receptor and oestrogen receptor beta was also evaluated in co-twin males aged 4 and 35 weeks, after treatment from birth to 4 weeks or from week 25 to week 35, respectively, with either vehicle or with GnRH antagonist at a dose known to suppress the neonatal testosterone surge completely. Only GnRH antagonist treatment during weeks 25-35 reduced androgen receptor immunoexpression, whereas immunoexpression of oestrogen receptor beta was unaffected by treatment during either period. On the basis of these findings it is suggested that: (i) neonatal marmoset Sertoli cells may be targets primarily for oestrogens rather than androgens; (ii) androgen receptor expression in the testes of neonatal and infant marmosets is not regulated in a straightforward way by testosterone; and (iii) high neonatal concentrations of plasma testosterone are not absolutely necessary for expression of androgen receptor in marmoset testes at this time.     

Assessment of the risk of solar ultraviolet radiation to amphibians. I. Dose-dependent induction of hindlimb malformations in the northern leopard frog (Rana pipiens)

A number of environmental stressors have been hypothesized as responsible for recent increases in limb malformations in several species of North American amphibians. The purpose of this study was to generate dose-response data suitable for assessing the potential role of solar ultraviolet (UV) radiation in causing limb malformations in a species in which this phenomenon seemingly is particularly prevalent, the northern leopard frog (Rana pipiens). Frogs were exposed from early embryonic stages through complete metamorphosis to varying natural sunlight regimes, including unaltered (100%) sunlight, sunlight subjected to neutral density filtration to achieve relative intensities of 85%, 75%, 65%, 50%, and 25% of unaltered sunlight, and sunlight filtered with glass or acrylamide to attenuate, respectively, the UVB (290-320 nm) and UVB plus UVA (290-380 nm) portions of the spectrum. The experiments were conducted in a controlled setting, with continual monitoring of UVB, UVA, and visible light to support a robust exposure assessment. Full sunlight caused approximately 50% mortality of the frogs during early larval development; no significant treatment-related mortality occurred under any of the other exposure regimes, including 100% sunlight with glass or acrylamide filtration. There was a dose-dependent (p < 0.0001) induction of hindlimb malformations in the frogs, with the percentage of affected animals ranging from about 97% under unaltered sunlight to 0% in the 25% neutral density treatment. Malformations were comprised mostly of missing or truncated digits, and generally were bilateral as well as symmetrical. Filtration of sunlight with either glass or acrylamide both significantly reduced the incidence of malformed limbs. The estimated sunlight dose resulting in a 50% limb malformation rate (ED50) was 63.5%. The limb ED50 values based on measured sunlight intensities corresponded to average daily doses of 4.5 and 100 Wh x m(-2) for UVB and UVA, respectively. Exposure to sunlight also resulted in increased eye malformations in R. pipiens, however, the dose-response relationship for this endpoint was not monotonic. The results of this study, in conjunction with measured or predicted exposure data from natural settings, provide a basis for quantitative prediction of the risk of solar UV radiation to amphibians.     

Proteins in white wine, I: Procyanidin occurrence in soluble proteins and insoluble protein hazes and its relationship to protein instability

The presence of procyanidins in wine protein fractions was established by a chemical assay and by pyrolysis DI-EI MS/MS of proteins. The chemical assay, involving acid-catalysed oxidative degradation of the procyanidins, gave cyanidin which was specifically quantified by HPLC. The assay was calibrated with purified grape seed tannin (GST); procyanidin was expressed in μg GST. Cyanidin yields were little altered by the presence of a large excess of protein. The limit of detection of the assay was 1 μg GST and the limit of quantification 3.5 μg GST. Both heat-induced and natural hazes isolated from various white wines were all shown to contain procyanidins, with a content ranging from < 0.02 to 4.9% (w/w). Although a crude soluble protein isolate from white wine contained a detectable amount of procyanidins, none were found in fractions separated chromatographically from this isolate. This observation, and the absence of procyanidins in resolubilised heat-induced haze, demonstrated that procyanidins are only weakly associated with both heat-induced hazes and soluble wine proteins. Nevertheless, procyanidins appear to be implicated in the formation of protein hazes in wine, because many soluble wine proteins that had been rendered free of procyanidins would precipitate to give haze in wine but not in model wine which was devoid of phenolic compounds.     

环保印染助剂及绿色加工技术

近年来，世界各国尤其是欧美等发达国家陆续出台了相关的环保法规和纺织品环保标准，对进口纺织品实施严格的检测。同时，国际纺织品服装市场对产品的绿色环保要求，人们消费意识中对绿色产品的要求也越来越高。因而，在纺织品生产过程的各个环节中必须考虑到绿色问题，     

Absence of seasonal changes in FSHR gene expression in the cat cumulus-oocyte complex in vivo and in vitro

Domestic cat oocytes are seasonally sensitive to FSH. Compared with those collected during the breeding season, oocytes from the nonbreeding (NB) season require more FSH during in vitro maturation to achieve comparable developmental competence. This study tested the hypothesis that this seasonal variation was due to altered expression of FSH receptors (FSHR) and/or FSH-induced genes. Relative expression levels of FSHR mRNA and FSH-enhanced gene estrogen receptor β (ESR2) were measured by qPCR in whole ovaries and immature cumulus-oocyte complexes (COCs) isolated from cat ovaries during the natural breeding vs NB seasons. Expression levels of FSH-induced genes prostaglandin-endoperoxide synthase 2 (PTGS2), early growth response protein-1 (EGR1), and epidermal growth factor receptor (EGFR) were examined in mature COCs from both seasons that were a) recovered in vivo or b) matured in vitro with conventional (1 μg/ml) or high (10 μg/ml) FSH concentrations. Overall, FSHR mRNA levels were lower in whole ovaries during the NB compared with breeding season but were similar in immature COCs, whereas ESR2 levels did not differ in either group between intervals. We observed changes in PTGS2, EGR1, and EGFR mRNA expression patterns across maturation in COCs within but not between the two seasons. The lack of seasonal differentiation in FSH-related genes was not consistent with the decreased developmental capacity of oocytes fertilized during the NB season. These findings reveal that the seasonal decrease in cat oocyte sensitivity to FSH occurs both in vivo and in vitro. Furthermore, this decline is unrelated to changes in expression of FSHR mRNA or mRNA of FSH-induced genes in COCs from antral follicles.     

Role of FSH, numbers of FSH receptors and testosterone in the regulation of inhibin secretion during the seasonal testicular cycle of adult rams

The regulation of inhibin secretion has not been elucidated fully in male ruminants. The aim of this study was to determine the relative importance of FSH and testosterone concentrations, and FSH receptors, in the control of secretion of immunoactive inhibin in rams. In Expt 1, temporal changes in hormone concentrations and testicular FSH binding were determined for two groups of rams (n = 4) kept under opposite, alternating 4 month periods of long (16 h light:8 h dark) and short (8 h light:16 h dark) days. Testicular biopsies (1-2 g) were collected when the testes were regressed, redeveloping, redeveloped and regressing. In Expt 2, separate groups of rams (n = 4) kept under natural photoperiod (latitude 45 degrees 48 minutes N) were designated as controls or passively immunized (for 3 weeks) with sufficient oestradiol antiserum to increase testosterone secretion without altering LH and FSH; this was done when the testes were regressed (non-breeding season) and redeveloped (breeding season). In both groups of rams (Expt 1), 'seasonal' increases in FSH concentrations began a few weeks earlier than did increases in inhibin concentrations. FSH reached maximum concentrations during testicular recrudescence, whereas numbers of FSH receptors in the testis and circulatory inhibin concentrations did not reach peak values until the testes were fully developed. Numbers of FSH receptors per testis, but not FSH concentration, were positively correlated (r = 0.65) with inhibin concentrations across the four stages of the testicular cycle. Near the end of testicular recrudescence early in the breeding season (Expt 2), relatively high FSH concentration was associated with increased abundance of FSH receptor mRNA (90%) and number of receptors (45%) in the testis and increased inhibin concentrations (50%), compared with when the testes were regressed. Moderate, physiological increases in testosterone secretion in immunized rams did not affect inhibin in either season. These results indicate that: (i) FSH stimulation of immunoactive inhibin secretion by Sertoli cells as testes recrudesce is via increases in secretion (early) and cognate receptors (late); (ii) FSH upregulates the synthesis of its own receptor late in recrudescence; and (iii) the positive correlation (r = 0.70) observed between circulatory testosterone and immunoactive inhibin does not reflect a causal relationship.     

The green halo: Mechanisms and limits of the eco-label effect

Consumers believe that “eco-labeled” products taste better, which, at least in part, may be an effect of the label. The purpose of the current series of experiments was to examine some mechanisms and limits of this eco-label effect. In Experiment 1, an eco-label effect of similar magnitude was found for taste ratings of both conventional and organic bananas. Experiment 2 showed eco-label effects for a wider range of judgmental dimensions (i.e., health, calories, vitamins/minerals, mental performance, and willingness to pay) and the effect was about the same in magnitude for judgments of grapes and raisins. Experiment 3, with water as the tasted product, found no eco-label effect on judgments of taste, calories and vitamins/minerals, but an effect on willingness to pay, judgments of health benefits and judgments of mental performance benefits. Experiments 2 and 3 also included questionnaires on social desirability traits, schizotypal traits and pro-environmental consumer traits. The last was the strongest predictor of the eco-label effect amongst the three. In all, the eco-label effect is a robust phenomenon, but depends on interactions between product type and judgmental dimension. Implications for several accounts of the effect are discussed.     

Optimization of DNA-based vaccination in cows using green fluorescent protein and protein A as a prelude to immunization against staphylococcal mastitis

Staphylococcus aureus is a contagious pathogen that often results in chronic intramammary infections in dairy cows. Current vaccine formulations are ineffective in preventing this infection. The objective of this study was to stimulate an immune response in dairy cows through injection of plasmid DNA designed to express staphylococcal Protein A in transfected cells. Intramuscular and intradermal vaccination sites were evaluated using a plasmid containing the human cytomegalovirus (CMV) promoter/enhancer directing expression of green fluorescent protein (pcDNA3/GFP). DNA was delivered by needle and syringe, or by high-, intermediate-, or low-pressure jet injections (Ped-o-Jet and LectraJet). Five cows per treatment were injected with 0.5 mg of plasmid DNA at 6, 4, and 2 wk prepartum. Serum antibody levels determined by ELISA indicated that intradermal high-pressure jet injection elicited a greater immune response compared to needle and syringe injection. Differences in antibody production among low-pressure and needle and syringe treatment groups were not significant. An expression plasmid containing the CMV promoter/enhancer driving expression of the Fc-binding domain of S. aureus Protein A was coinjected into cows by vulvamucosal vaccination using the high-pressure Ped-o-Jet. Beginning 6 wk prepartum, groups of cows (n = 5) were injected three times at 2-wk intervals with DNA in saline, DNA in aluminum phosphate adjuvant, or served as noninjected controls. A cellular immune response to Protein A was detected in 4 of 10 animals, while cellular responses to GFP were not detected. Humoral responses to Protein A were observed in 6 of 10 animals and to GFP in 2 of 10 animals. Aluminum phosphate adjuvant appeared to enhance antibody production in response to Protein A. In experiment 3, a protein boost injection of Protein A was given to six animals approximately 5 mo postpartum. Three animals were nonvaccinated controls, and three were among those stimulated to produce antibody in response to the DNA-based vaccine. These results showed that Protein A specific antibodies remained elevated as compared to nonvaccinated controls and were stimulated in response to the protein boost. However, the magnitude of the response in animals previously vaccinated with DNA was not different than that observed in the nonvaccinated controls. We have shown that a humoral and cellular immune response to abbreviated Protein A can be raised in dairy cows using intravulvamucosal jet injection of a DNA-based vaccine.     

Quantification of monomeric and polymeric wheat proteins and the relationship of protein fractions to wheat quality

Wheat protein composition is important for understanding the biochemical basis of wheat quality. The objective of this study was to design a simple protein fractionation protocol with low cross‐contamination and to show that these protein fractions were associated with wheat quality. The protocol consists of three sequential extractions from 100 mg of flour with 7.5% propan‐1‐ol and 0.3 M sodium iodide (monomeric‐rich protein), 50% propan‐1‐ol (soluble glutenin‐rich protein) and 40% propan‐1‐ol and 0.2% dithiothreitol (insoluble glutenin‐rich protein). Nitrogen content of protein solubility groups was determined from dry residues using an automated combustion nitrogen analyser. About 90% of the total protein in the flour was solubilised. Cross‐contamination of protein fractions was evaluated by SDS‐PAGE, SE‐HPLC and RP‐HPLC. Variation in nitrogen content of the protein solubility fractions was lowest for monomeric‐rich protein (<2%) and insoluble glutenin‐rich protein (<4%). Three wheats with similar high‐molecular‐weight (HMW) glutenin subunit composition, Alpha 16, Glenlea and Roblin, varied significantly (P ≤ 0.05) in the proportion of monomeric‐rich and insoluble glutenin‐rich protein in the flour. Dough rheological properties were directly related to the proportion of insoluble glutenin‐rich protein and inversely related to the proportion of monomeric‐rich protein. The protocol was validated using an expanded set of 11 wheats which also showed that inter‐cultivar differences in the proportion of monomeric‐rich, insoluble glutenin‐rich protein and glutenin‐to‐gliadin ratio in the flour governed dough rheological properties such as mixograph, farinograph and microextension tests. The protocol has merit for quality screening in wheat‐breeding programmes when the sample size is too small or when time constraints limit the ability to perform traditional rheological tests. For the Department of Agriculture and Agri‐Food, Government of Canada, Copyright © Minister of Public Works and Government Services Canada 2003. Published for SCI by John Wiley & Sons, Ltd.     

Leaf:fruit ratio and irrigation supply affect seasonal changes in minerals,organic acids and sugars of mango fruit

To determine the effects of assimilate and water supply on the determination of mango fruit quality, the seasonal variations of minerals, acids and sugar concentrations were investigated over two successive years. To manipulate the assimilate supply, selected branches were girdled to provide ratios of 10, 25, 50 and 100 leaves per fruit. Irrigation was managed to provide two types of water supply treatments. Fruit growth rate was greater when increasing the leaf:fruit ratio. Structural dry matter content and total dry matter content of flesh were higher in fruit with higher leaf:fruit ratios. Treatments had no effect on the structural to total dry matter ratio of flesh. Potassium and magnesium to structural dry weight ratios were not affected by treatments, whereas the calcium to structural dry weight ratio was higher in the flesh of fruit grown under low leaf:fruit ratios. Low assimilate supply increased the ratios of malic and citric acid to structural dry weight. This treatment had little effect on acid concentrations. Glucose and fructose to structural dry weight ratios were higher when assimilate supply was lower. Low leaf:fruit ratios increased fructose concentration but not glucose concentration. Irrigation treatment strongly affected fructose concentration. Sucrose concentration, based either on structural dry matter or on fresh matter, was significantly increased by higher leaf‐to‐fruit ratios. When the fruit was close to maturity, levels of sucrose storage and starch breakdown were positively correlated with assimilate supply. Levels of starch breakdown were correlated with irrigation supply. The effects of these treatments on sugar concentrations may change fruit taste. Copyright © 2004 Society of Chemical Industry