Effect of germination, seed abrasion and seed size on polyphenol oxidase assay activity in wheat   总被引：7，自引：0，他引：7  

T. Demeke    H.-G. Chang  C. F. Morris 《Plant Breeding》2001,120(5):369-373

Polyphenol oxidase (PPO) is one of the major enzymes responsible for browning of wheat food products. Wheat cultivars differ in PPO activity and plant breeders wish to select germplasm and cultivars with low PPO activities. Prior to harvest, seeds may be exposed to conditions conducive to preharvest sprouting and mechanical damage may occur during harvesting and subsequent handling. Sprouting, mechanical damage and seed size may affect PPO assay activity and therefore impinge upon the breeder's ability to accurately select low PPO genotypes. The effects of incipient germination, mechanical abrasion and seed size on PPO assay activity were investigated using the cultivars ‘Klasic’(hard white spring, high PPO), ‘Penawawa’(soft white spring, high PPO) and ‘ID377s’(hard white spring, low PPO). The influence of embryo vs. distal portions of the seed on PPO assay activity was also examined. PPO activity was assayed with constant mixing using L‐3,4‐dihydroxyphenyl alanine (L‐DOPA) substrate at pH 6.5 at room temperature; absorbance of the reaction solution was measured at 475 nm. There was no change in PPO assay activity for seeds imbibed in water for up to 8 h. PPO assay activity increased in seeds imbibed from 8 to 16 h, and then gradually declined with increasing imbibing time. PPO assay activity initially increased as a result of mechanical abrasion but then gradually declined with increasing abrasion time. Large seeds had a higher total PPO assay activity than small seeds, but the difference in activity was not proportional to seed weight. There was only a slight difference in PPO assay activity between half‐seeds with or without the embryo. Overall, PPO assay activity in dry seeds was stable and exposure of seeds to injury and moisture did not make any significant change in PPO assay activity among the cultivars or their relative rankings.  相似文献   

Umami compounds are a determinant of the flavor of potato (Solanum tuberosum L.)     

Morris WL  Ross HA  Ducreux LJ  Bradshaw JE  Bryan GJ  Taylor MA 《Journal of agricultural and food chemistry》2007,55(23):9627-9633

Vegetable flavor is an important factor in consumer choice but a trait that is difficult to assess quantitatively. The purpose of this study was to assess the levels of the major umami compounds in boiled potato tubers, in cultivars previously assessed for sensory quality. The free levels of the major umami amino acids, glutamate and aspartate, and the 5'-nucleotides, GMP and AMP, were measured in potato samples during the cooking process. Tubers were sampled at several time points during the growing season. The levels of both glutamate and 5'-nucleotides were significantly higher in mature tubers of two Solanum phureja cultivars compared with two Solanum tuberosum cultivars. The equivalent umami concentration was calculated for five cultivars, and there were strong positive correlations with flavor attributes and acceptability scores from a trained evaluation panel, suggesting that umami is an important component of potato flavor.  相似文献   

Stretch-inactivated ion channels coexist with stretch-activated ion channels   总被引：9，自引：0，他引：9  

C E Morris  W J Sigurdson 《Science (New York, N.Y.)》1989,243(4892):807-809

Stretch-activated ion channels of animal, plant, bacterial, and fungal cells are implicated in mechanotransduction and osmoregulation. A new class of channel has now been described that is stretch-inactivated. These channels occur in neurons, where they coexist with stretch-activated channels. Both channels are potassium selective. The differing stretch sensitivities of the two channels minimize potassium conductance over an intermediate range of tension, with the consequence that, over this same range, voltage-gated calcium channels are most readily opened. Thus, by setting the relation between membrane tension and transmembrane calcium fluxes, stretch-sensitive potassium channels may participate in the control of calcium-dependent motility in differentiating, regenerating, or migrating neurons.  相似文献   

THE USE OF CUTTING TREATMENTS DESIGNED TO SIMULATE DEFOLIATION BY SHEEP     

R. M. Morris 《Grass and Forage Science》1970,25(3):198-206

A series of cutting treatments was designed to simulate the defoliation process under sheep grazing, in order to obtain more accurate measures of the production processes in the sward than can be obtained in the presence of the grazing animal. Two rotational grazing managements were simulated, together with three continuous grazing managements involving the maintenance of a roughly constant LAI within a sward, as described earlier (10). Harvested yield was measured, and the dry weight of material which died without heing harvested was estimated. From these, gross aerial growth, i.e., the amount of new living material produced in the sward, was calculated. The maximum harvested yield was obtained by rotational defoliation to 3 cm every 4 weeks, hut this was derived from the minimum gross aerial growth. Maximum gross aerial growth occurred under the simulated continuous grazing treatments at the higher levels of LAI. This difference was due largely to the death and subsequent decay of leaves. Up to 50% of the material which grew was lost in this way. The need to distinguish between growth and harvested yield when evaluating grazing managements was stressed.  相似文献   

A randomized trial investigating the efficacy and safety of water soluble micellar paclitaxel (Paccal Vet) for treatment of nonresectable grade 2 or 3 mast cell tumors in dogs     

Vail DM  von Euler H  Rusk AW  Barber L  Clifford C  Elmslie R  Fulton L  Hirschberger J  Klein M  London C  Martano M  McNiel EA  Morris JS  Northrup N  Phillips B  Polton G  Post G  Rosenberg M  Ruslander D  Sahora A  Siegel S  Thamm D  Westberg S  Winter J  Khanna C 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2012,26(3):598-607

Background

Effective treatments for dogs with advanced stage mast cell tumors (MCT) remain a pressing need. A micellar formulation of paclitaxel (paclitaxel [micellar]) has shown promise in early‐phase studies.

Hypothesis/Objectives

The objective was to demonstrate greater activity for paclitaxel (micellar) compared with lomustine. The null hypothesis was μ_p = μ_L (ie, proportion of responders for the paclitaxel [micellar] and lomustine groups, respectively).

Animals

Two hundred and fifty‐two dogs with advanced stage nonresectable grade 2 or 3 MCT.

Methods

Prospective multicenter randomized double‐blind positive‐controlled clinical trial. The primary endpoint was confirmed overall response rate (CORR) at 14 weeks. A secondary endpoint, biologic observed response rate (BORR), also was calculated. Safety was assessed by the characterization and grading of adverse events (AE).

Results

Overall CORR (7% versus 1%; P = .048) and BORR (23% versus 10%; P = .012) were greater for paclitaxel (micellar) compared with lomustine. Paclitaxel (micellar)‐treated dogs were 6.5 times more likely to have a confirmed response and 3.1 times more likely to experience a biologic observed response. The majority of AE with paclitaxel (micellar) were transient and clinically manageable. Twenty‐seven dogs (33%) receiving lomustine were discontinued because of hepatopathy compared with 3 dogs (2%) receiving paclitaxel (micellar) (P < .0001; odds ratio 26.7).

Conclusions and Clinical Importance

Paclitaxel (micellar)'s activity and safety profile are superior to lomustine. The addition of an active and novel taxane to the veterinary armamentarium could fill a substantial need and, as its mechanism of action and AE profile do not overlap with currently available TKI, its availability could lead to effective combination protocols.  相似文献   

Prevalence of Bartonella species, hemoplasmas, and Rickettsia felis DNA in blood and fleas of cats in Bangkok, Thailand     

Assarasakorn S  Veir JK  Hawley JR  Brewer MM  Morris AK  Hill AE  Lappin MR 《Research in veterinary science》2012,93(3):1213-1216

Flea infestations are common in Thailand, but little is known about the flea-borne infections. Fifty flea pools and 153 blood samples were collected from client-owned cats between June and August 2009 from veterinary hospitals in Bangkok, Thailand. Total DNA was extracted from all samples, and then assessed by conventional PCR assays. The prevalence rates of Bartonella spp. in blood and flea samples were 17% and 32%, respectively, with DNA of Bartonella henselae and Bartonella clarridgeiae being amplified most commonly. Bartonella koehlerae DNA was amplified for the first time in Thailand. Hemoplasma DNA was amplified from 23% and 34% of blood samples and flea pools, respectively, with 'Candidatus Mycoplasma haemominutum' and Mycoplasma haemofelis being detected most frequently. All samples were negative for Rickettsia felis. Prevalence rate of B. henselae DNA was increased 6.9 times in cats with flea infestation. Cats administered flea control products were 4.2 times less likely to be Bartonella-infected.  相似文献   

Western red cedar extractives associated with durability in ground contact   总被引：1，自引：1，他引：0  

Paul I. Morris  Rod Stirling 《Wood Science and Technology》2012,46(5):991-1002

Western red cedar (WRC) is well known for its natural durability. However, the roles of all the extractives that may be associated with this durability are not fully understood. The literature primarily credits the thujaplicins, with a lesser role for the lignans; however, previous work has identified highly durable material with low thujaplicin content. To elucidate the relative importance of various extractives, the decay resistance of WRC stakes at four test sites was compared with data on the content of specific extractives to determine whether there was any detectable association. The concentration of plicatic acid, a lignan, was associated with the decay resistance of WRC lumber in ground contact. An unidentified, unquantified compound (B) appeared to be similarly associated with decay resistance. The thujaplicins were only weakly associated with the decay resistance of WRC in ground contact.  相似文献   

Assessing the Past: The Importance of Cultivation History in EBIPM Success     

Lesley R. Morris  Thomas A. Monaco 《Herpetological Monographs》2012,34(6):19-22

  相似文献   

Genotype and Environment Variation for Arabinoxylans in Hard Winter and Spring Wheats of the U.S. Pacific Northwest     

Shuobi Li  Craig F. Morris  Arthur D. Bettge 《Cereal Chemistry》2009,86(1):88-95

The development of high‐quality wheat (Triticum aestivum L.) cultivars depends on a thorough understanding of the constituents of grain and their variation due to genetics and environment. Arabinoxylans (pentosans) are key constituents of wheat grain and have broad and far‐reaching influences on milling and baking quality. However, variation in arabinoxylans due to genotype and environment are not fully understood. In this study, 25 hard winter and 25 hard spring wheat commercial cultivars and advanced breeding lines developed from eight public and private breeding programs in the U.S. Pacific Northwest were analyzed for water‐extractable and total arabinoxylan contents (WE‐AX and total AX), and the proportion of total AX that was water‐extractable. Winter and spring genotypes were grown in three environments each. The results indicated that there were significant differences among both sets of hard wheat genotypes for WE‐AX, total AX, and proportion of total AX that was WE‐AX. The WE‐AX and total AX mean content ranges for the winter cultivars were 0.390–0.808 and 3.09–4.04%, respectively; and for the spring cultivars 0.476–0.919 and 3.94–4.70%, respectively. WE‐AX as a percentage of total AX was similar between the two genotype sets, 11.7–23.0%. Arabinoxylan fractions were generally not correlated with grain protein, test weight, and kernel hardness. The two highest correlations for winter wheats were between protein and total AX (r = –0.40) and test weight and percentage of total AX that were water‐extractable (r = 0.37) for winter wheats. Among spring wheats, single‐kernel characterization system hardness was negatively correlated with WE‐AX and proportion of total AX that was WE‐AX (r = –0.46 and –0.51, respectively). Although often significant, arabinoxylan fractions were usually not highly intercorrelated, indicating some independence of traits. Notable genotypes, being especially high or low for one or more arabinoxylan fraction and, thus, candidates for further genetic study and cross‐breeding, included Juniper, Eddy, and ORN980995 winter wheats, and Hollis, Alta Blanca, and WQL9HDALP spring wheats. Although the results indicate that arabinoxylan fractions of wheat grain can be highly influenced by environment, there is clear support for the existence of genetic differences, especially for WE‐AX and the proportion of total AX that is water‐extractable. As such, the manipulation of arabinoxylan content of wheat grain seems to be a reasonable breeding objective.  相似文献   

Cloning and phylogenetic analysis of polyphenol oxidase genes in common wheat and related species     

X. Y. He  Z. H. He  C. F. Morris  X. C. Xia 《Genetic Resources and Crop Evolution》2009,56(3):311-321

Cloning and phylogenetic analysis of polyphenol oxidase (PPO) genes in common wheat and its relatives would greatly advance the understanding of molecular mechanisms of grain PPO activity. In the present study, six wheat relative species, including T. urartu, T. boeoticum, T. monococcum, T. dicoccoides, T. durum and Ae. tauschii, were sampled to isolate new alleles at Ppo-A1 and Ppo-D1 loci corresponding to common wheat PPO genes, and seven new alleles were identified from these species, which were designated as Ppo-A1c (from T. urartu), Ppo-A1d (T. boeoticum), Ppo-A1e (T. monococcum and T. durum), Ppo-A1f (T. dicoccoides), Ppo-A1g (T. durum), Ppo-D1c (Ae. tauschii) and Ppo-D1d (Ae. tauschii), respectively. Five out of the seven alleles detected in the wheat relatives contained an open reading frame (ORF) of 1,731 bp, encoding a polypeptide of 577 residues, which is the same as those of Ppo-A1 and Ppo-D1 genes in common wheat, whereas, the full-length ORF of the allele Ppo-A1g from T. durum was not obtained, and a 73-bp deletion occurred in the third exon of Ppo-D1d, an allele from Ae. tauschii, resulting in a shorter polypeptide of 466 amino acids. The 191-bp insertion in the first intron reported previously in common wheat was also found in T. dicoccoides lines, implying that more than one tetraploid wheat lines may be involved in the origination of common wheat. Phylogenetic trees were constructed using the genomic DNA sequences of the seven alleles, together with four from common wheat and four partial PPO gene sequences deposited in GenBank. The genome tribe A was divided into two clusters, one of which contained Ppo-A1d and Ppo-A1e, and the other included the remaining five alleles at Ppo-A1 locus. The alleles from different clusters showed high sequence divergences, indicated by dozens of SNPs and five to six InDels. The genome tribe D comprised the alleles Ppo-D1a, Ppo-D1c, Ppo-D1d and Ppo-D1b, and the former three were clustered together, showing significant sequence divergence from Ppo-D1b. In addition, the relationships between these allelic variants and grain PPO activities were also discussed. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献