Decay development in living sapwood of coniferous and deciduous trees inoculated with six wood decay fungi     

Giuliana Deflorio  Craig Johnson  Siegfried Fink  Francis Willis Mathew Robert Schwarze 《Forest Ecology and Management》2008

Development of decay and/or discoloration was assessed in the functional sapwood of one coniferous and three deciduous trees after wounding and artificial inoculation with six wood decay fungi. Living stems of mature Douglas fir, beech, oak, and sycamore trees were wounded in spring 2002 and immediately inoculated with brown, white, and soft rot fungi. Extent of discoloration and decay, wood weight loss, and total phenols in the reaction zone (zone of active response at a dynamic interface between living sapwood and wood colonized by decay fungi) were assessed 16 and 28 months after inoculation.  相似文献   

Occurrence of Puroindoline Alleles in Chinese Winter Wheats     

Lanqin Xia  Feng Chen  Zhonghu He  Xinmin Chen  Craig F. Morris 《Cereal Chemistry》2005,82(1):38-43

Grain hardness is one of the most important characters that determine the end‐use quality of bread wheat (Triticum aestivum L.). Mutations in genes encoding either puroindoline a (Pina) or b (Pinb) have been associated with hard grain texture, i.e., Pina null at Pina‐D1 or seven mutations at Pinb‐D1. In this study, the diversity of puroindoline alleles in 251 Chinese winter wheat cultivars and advanced lines from four major autumn‐planted wheat regions were investigated. Among the examined cultivars, 79 were classified as soft, while 53 were mixed in hardness, and 119 were uniformly hard. Of these hard winter wheats, three of the seven reported mutation types were observed, with Pina‐D1a/Pinb‐D1b being the dominant type for hard texture; 91 genotypes carried this allele. Sixteen genotypes had the Pina‐D1b allele, and two genotypes had the Pinb‐D1d allele. A new mutation, designated as Pinb‐D1p, was detected in 10 hard genotypes, with a single nucleotide (A) deletion corresponding to position 42 in the amino acid sequence of puroindoline b, involving a lysine (K) to asparagine (N) change, and leading to a shift in the open reading frame (ORF). This deletion disrupts the last part of the tryptophanrich domain, changing it from KWWK to NGGR, which is considered essential for the lipid‐binding activity of this protein, and results in a stop codon corresponding to position Pro‐60 in the amino acid sequence. The characterization of different hardness alleles provides useful information in understanding the mechanism underlying the formation of endosperm hardness while providing breeders the means of manipulating this important trait.  相似文献   

ULTRASONOGRAPHIC EVALUATION OF THE CANINE SHOULDER     

Craig D.  Long  DVM  Thomas G.  Nyland  DVM 《Veterinary radiology & ultrasound》1999,40(4):372-379

The aim of this study was to determine the normal ultrasonographic anatomy of the canine shoulder. Fourteen shoulders from 7 clinically normal mid-sized dogs were radiographed and imaged using high frequency ultrasound. Each shoulder was isolated postmortem, and the ultrasonographic and gross anatomy was studied during dissection. The ultrasonographic appearance of the shoulder specimens was similar to that found in the live dogs. Twenty-four shoulders isolated postmortem from 12 variably sized dogs were also used to characterize the normal ultrasound anatomy over a range of sizes. Important anatomic structures that could be consistently evaluated were the biceps tendon and bursa, the bicipital groove surface, the supraspinatous tendon, the infraspinatous tendon, the teres minor tendon, and the caudal aspect of the humeral head. Results of ultrasonographic examination of 4 dogs with shoulder lameness are described to illustrate some applications of canine shoulder ultrasonography in the evaluation of the canine shoulder. In these dogs, ultrasound was a valuable tool to evaluate effusion and synovial proliferation within the bicipital bursa, supraspinatous and biceps tendinitis, biceps tendon strain, and dystrophic calcification.  相似文献   

Pedigree Reconstruction with Genome-Wide Markers in Potato     

Jeffrey B. Endelman  Cari A. Schmitz Carley  David S. Douches  Joseph J. Coombs  Benoit Bizimungu  Walter S. De Jong  Kathleen G. Haynes  David G. Holm  J. Creighton MillerJr  Richard G. Novy  Jiwan P. Palta  David L. Parish  Gregory A. Porter  Vidyasagar R. Sathuvalli  Asunta L. Thompson  G. Craig Yencho 《American Journal of Potato Research》2017,94(2):184-190

Reliable pedigree information facilitates a scientific approach to breeding, but errors can be introduced in many stages of a breeding program. Our objective was to use single nucleotide polymorphisms (SNPs) to check the pedigree records of elite North American potato germplasm. A population of 719 tetraploids was genotyped with an Infinium SNP array, yielding 5063 high-quality markers. Based on pedigree records, the dataset contained 198 parent-offspring trios, of which 182 were consistent with the marker data. For 13 of the 16 trios with a pedigree error, the true parent was identified in the population. By comparing the additive relationship matrix calculated from pedigree with the genetic distance calculated from markers, an additional 24 pedigree modifications were proposed, including the paternity of several varieties developed with bulk pollen. To ensure accurate pedigree records are published in the future, we recommend that new varieties be SNP genotyped and checked against this dataset.  相似文献   

Extensive DNA inversions in the B. fragilis genome control variable gene expression     

Cerdeño-Tárraga AM  Patrick S  Crossman LC  Blakely G  Abratt V  Lennard N  Poxton I  Duerden B  Harris B  Quail MA  Barron A  Clark L  Corton C  Doggett J  Holden MT  Larke N  Line A  Lord A  Norbertczak H  Ormond D  Price C  Rabbinowitsch E  Woodward J  Barrell B  Parkhill J 《Science (New York, N.Y.)》2005,307(5714):1463-1465

The obligately anaerobic bacterium Bacteroides fragilis, an opportunistic pathogen and inhabitant of the normal human colonic microbiota, exhibits considerable within-strain phase and antigenic variation of surface components. The complete genome sequence has revealed an unusual breadth (in number and in effect) of DNA inversion events that potentially control expression of many different components, including surface and secreted components, regulatory molecules, and restriction-modification proteins. Invertible promoters of two different types (12 group 1 and 11 group 2) were identified. One group has inversion crossover (fix) sites similar to the hix sites of Salmonella typhimurium. There are also four independent intergenic shufflons that potentially alter the expression and function of varied genes. The composition of the 10 different polysaccharide biosynthesis gene clusters identified (7 with associated invertible promoters) suggests a mechanism of synthesis similar to the O-antigen capsules of Escherichia coli.  相似文献   

A comparison of four methods for measuring respiration in organic material     

Keith Van Cleve  Patrick I. Coyne  Enid Goodwin  Craig Johnson  Marilyn Kelley 《Soil biology & biochemistry》1979,11(3):237-246

Four methods for measurement of respiration (CO₂ evolution) were compared on uniformly prepared, birch forest-floor organic matter; the methods included infrared gas analysis (i.r.g.a.), gas chromatography (g.c.), KOH absorption of CO₂ (b.a.) and the Gilson respirometer. Respiration estimates were made at a single temperature and also at variable temperatures at constant moisture contents. The i.r.g.a. and b.a. methods gave maximum estimates for respiration; the g.c. gave lowest, with the Gilson intermediate. Lower estimates for the g.c. are attributed to the closed system employed, which included no means of increasing gas diffusion (such as a KOH-CO₂ sink or continuous gas flow) out of the sample into the unoccupied space of the respiration chamber.At 25°C, the minimum sensitivity of the g.c. and Gilson were 3.8 and 3.6 μg CO₂, respectively. The minimum sensitivity of the b.a. method (44 μg CO₂) could have been improved with use of a micro-liter burette for titrations. The least minimum sensitivity, 0.31 μg CO₂, was attained with the i.r.g.a.Conditions under which any of the techniques may be used to estimate respiration should be carefully worked out. The relationship between sample size, gas flow rate (open system), chamber atmosphere composition (closed system), and chamber design should be established with sufficient confidence so that stimulation of respiration by excessive gas flow rate, or exhaustion of O₂ or CO₂ inhibition through extended chamber closure does not adversely affect respiration estimates.  相似文献   

The Galápagos giant tortoises (Geochelone elephantopus) Part II: Conservation methods     

Craig G. MacFarland  José Villa  Basilio Toro 《Biological conservation》1974,6(3):198-212

Eight of the 11 surviving races of Galápagos tortoises are threatened due to decreased population sizes and predation and/or competition by introduced mammals. Systematic hunting has been effective for controlling and even eliminating goats on the less elevated, more sparsely vegetated, smaller islands and for controlling pigs, even on some of the larger islands. However, the method has been ineffective against dogs and cats and it is doubtful that it could be used to eliminate goats or pigs on the more elevated, larger islands which have a diversity of vegetation zones. Alternative control or extermination methods are being sought and tested for these feral mammals and black rats. In an attempt to increase yearly recruitment of hatchlings, lava corrals have been constructed around nests, resulting in almost 100 per cent success in preventing nest destruction by pigs; but the method was ineffective against dogs. While other control methods are being sought, young of the endangered races are being hatched and raised in captivity for restocking of endemic populations. During the past seven years, improved and highly successful techniques have been found for (1) establishment of breeding colonies and construction of artificial nesting sites, (2) transport of eggs from wild nests, (3) incubation of eggs, and (4) raising of young in captivity. By August 1972, 231 young of six races were being raised, and 71 4·5–6·5 year old captive raised tortoises released on Pinzón in 1970 and 1971 were in good condition and growing rapidly. The advantages of conducting the breeding/raising programme in the Galápagos rather than foreign locations are discussed.  相似文献   

The Galápagos giant tortoises (Geochelone elephantopus) Part I: Status of the surviving populations     

Craig G. MacFarland  José Villa  Basilio Toro 《Biological conservation》1974,6(2):118-133

Eleven of the original 15 races of Galápagos tortoises are known to survive. The populations of three of these may be self-replacing. The other eight are threatened with extinction, each by one or more of the following: (1) greatly decreased population size, (2) predation on nests and/or young by introduced pigs, dogs, cats, or black rats, and (3) competition for food resources with feral populations of goats or donkeys. Human exploitation of the tortoise populations has become relatively unimportant in the past few years for a number of reasons, including more wide-spread acceptance of protective laws and the increasing activity of the Servicio del Parque Nacional Galápagos and the Charles Darwin Research Station. Data on population sizes and sex structures, reproductive potential, and natural mortality rates suggest that all but two of the endangered populations could remain stable or even increase in size if the effects of introduced mammals were eliminated or greatly lessened.  相似文献   

Habitat attributes of landscape mosaics along a gradient of matrix development intensity: matrix management matters     

Megan J. Brady  Clive A. McAlpine  Craig J. Miller  Hugh P. Possingham  Greg S. Baxter 《Landscape Ecology》2009,24(7):879-891

The matrix is an important element of landscape mosaics that influences wildlife indirectly through its influence on habitat, and directly, if they live in or move through it. Therefore, to quantify and manage habitat quality for wildlife in modified landscapes, it is necessary to consider the characteristics of both patch and matrix elements of the whole landscape mosaic. To isolate matrix effects from the often simultaneous and confounding influence of patch and landscape characteristics, we identified nineteen 500 m radius landscapes in southeast Queensland, Australia with similar remnant forest patch attributes, habitat loss, and fragmentation, but exhibiting a marked gradient from rural through high-density suburban development of the matrix, quantified by a weighted road-length metric. We measured habitat disturbance, structure, and floristics in patch core, patch edge and matrix landscape elements to characterise how landscape habitat quality changes for small mammals. Correlation analyses identified that with increased matrix development intensity, human disturbance of core sites increased, predators and exotic plant species richness in matrix sites increased, and structural complexity (e.g. logs and stumps) in the matrix decreased. Ordination analyses showed landscape elements were most similar in habitat structure and floristics at low to moderate levels of matrix development, suggesting enhanced landscape habitat quality. Matrix development intensity was not, however, the greatest source of overall variation of habitat throughout landscapes. Many variables, such as landholder behaviour, complicate the relationship. For enhanced conservation outcomes the matrix needs to be managed to control disturbances and strategically plan for matrix habitat retention and restoration.  相似文献   

Comparison of Channel Catfish,Ictalurus punctatus,and Blue Catfish,Ictalurus furcatus,Fed Diets Containing Various Levels of Protein in Production Ponds     

Menghe H. Li  Edwin H. Robinson  Craig S. Tucker  Daniel F. Oberle  Brian G Bosworth 《Journal of the World Aquaculture Society》2008,39(5):646-655

A comparative study was conducted on growth and protein requirements of channel catfish, Ictalurus punctatus, and blue catfish, Ictalurus furcatus. Four diets containing 24, 28, 32, or 36% protein were fed to both channel (initial weight 6.9 g/fish) and blue (6.6 g/fish) catfish for two growing seasons. There were significant interactions between dietary protein and fish species for weight gain and feed conversion ratio (FCR). No significant differences were observed in weight gain of channel catfish fed various protein diets, whereas higher protein diets (32 and 36%) resulted in better weight gain in blue catfish than lower protein diets (24 and 28%). No consistent differences were observed in the FCR of channel catfish fed various levels of dietary protein, whereas significantly higher FCRs were noted in blue catfish fed the 24 and 28% protein diets compared with fish fed 32 and 36% protein diets. Regardless of dietary protein levels, blue catfish had higher carcass, nugget, and total meat yield, and higher fillet moisture and protein, but lower fillet yield and fillet fat. Regardless of fish species, fish fed the 36% protein diet had higher carcass, fillet, and total meat yield than fish fed the 28 and 32% protein diets, which in turn had higher yields than fish fed the 24% protein diet. It appears that blue catfish can be successfully cultured by feeding a 32% protein diet.  相似文献