bluuebunny/crossref_metadata_2025 huggingface dataset:
In vitro susceptibility of Cryptococcus neoformans serotypes to GM 237354 derivative of the sordarin class
Authors: Torres‐Rodríguez J. M. , Morera Y. , Baró T. , López O. , Alía C. , Jiménez T.
Published: March 2003

Summary.  In vitro susceptibility to the sordarin derivative GM 237354 and amphotericin B were tested in a total of 190 Cryptococcus neoformans clinical isolates from different geographical areas of Spain and South American countries. Minimal inhibitory concentrations (MICs) were obtained using the NCCLS reference microbroth dilution method and analysed according the serotypes of Cr. neoformans. The MICs for amphotericin B were lower than 1.0 μg ml−1 (MIC90% 0.5 μg ml−1, MIC50% 0.125 μg ml−1) but five isolates showed MICs of 2.0 μg ml−1 to GM 237354 (MIC90% 1.0 μg ml−1, MIC50% 0.5 μg ml−1). Cryptococcus neoformans var. gattii serotype B, was significantly less susceptible than A and AD serotypes (P=0.047 and P=0.022, respectively).
An unusual case of tinea capitis due to Trichophyton soudanense
Authors: Romano Clara , Miracco Clelia , Faggi E. , Cuccia A. , Pini G.
Published: March 2003

Summary A case of tinea capitis due to Trichophyton soudanense observed in a 4‐year‐old African girl is described. The infection manifested with diffuse pustular lesions of the scalp. Diagnosis was based on culture. Genome study by single primer PCR fingerprinting was also performed. A younger sister, aged 10 months, was the healthy carrier of the mycete.
Variation of resistance to Pseudocercosporella herpotrichoides (Fron) Deighton in wheat genotypes carrying the gene Pch‐1
Authors: Lind V.
Published: March 2003

The effect of the gene Pch‐1 on the resistance of wheat to Pseudocercosporella herpotrichoides was studied at four growth stages. The germplasm used consisted of adapted cultivars, genotypes provided by European plant breeders, near‐homozygous lines and double haploid lines developed from our own breeding projects. The resistance was measured by ELISA. At all growth stages, genotypes carrying Pch‐1 differed significantly in resistance. At early growth stages, there was a strong effect of the gene in most genotypes, but later the effect decreased and significant genotypes‐environment interactions appeared. In addition, minor genes became more important and determined the level of adult plant resistance that proved to be inherited quantitatively. Pch‐1 was of minor importance for this type of resistance. It is concluded that a high and long‐lasting resistance level could be attained if the two genetically different sources of resistance were combined (resistance at juvenile stages, induced by Pch‐1, and quantitative resistance at adult stages).
SCAR and RAPD markers associated with 18‐carbon fatty acids in rapeseed, Brassica napus
Authors: Hu J. , Li G. , Struss D. , Quiros C. F.
Published: March 2003

Breeding rapeseed for enhanced oil quality includes the development of varieties with low linolenic acid content. The breeder also aims to develop varieties with a high linoleic acid content because of its nutritional value. Restriction fragment length polymorphism (RFLP) and random amplified polymorphic DNA (RAPD) markers have been developed for linolenic acid content, but they are not best suited for a direct application in marker‐assisted selection. The RFLP technique is too complex and time‐consuming and RAPD markers lack codominance, precluding the distinction of homozygous from heterozygous individuals. In this report the conversion of a RAPD marker to a codominant sequence characterized amplified region (SCAR) marker named L1L9 is described. One of the alleles consisting of an 899 bp fragment (allele A), is associated with low linolenic acid content. The other allele consists of an 641 bp fragment (allele B) and is associated with high linolenic acid content. This marker explains approximately 25% of the genetic variation for this trait. Linkage analysis in the mapping population indicates that the SCAR marker probably tags an ω‐3 desaturase gene in B. napus. Two RAPD markers were found to be associated with oleic/linoleic acid content. Markers M14‐350 and I06‐650 explained approximately 10% and 7% of the genetic variation for linoleic acid content, respectively. These two markers were found linked at 12.3cM in the segregating B. napus F2 progeny used for mapping. All the markers reported in this paper should be useful in breeding programmes for developing high linoleic and low linolenic acid rapeseed varieties.
Assessment of genetic and phenotypic variation among intraspecific somatic hybrids of potato, Solanum tuberosum L.
Authors: Gavrilenko T. , Thieme R. , Tiemann H.
Published: March 2003

Intraspecific somatic hybrids have been produced by protoplast fusion in eight combinations involving 10 dihaploids (2n= 2x= 24) in an attempt to provide new material for potato breeding. Cytological analysis revealed extensive variation in chromosome number, such as aneuploid, aneusomatic and mixoploid hybrids. Most of the hybrids represented the expected chromosome number of 48; however, the frequency of aneuploids reached 50% in some combinations. Some hybrids carried structurally rearranged chromosomes and exhibited a high frequency of aberrant anaphases. Isozyme and random amplified polymorphic DNA (RAPD) patterns of the hybrids from the same fusion combination were uniform. In the field, somatic hybrids showed wide phenotypic variation in 20 morphological characters. There was a significant correlation between certain leaf characters and the ploidy level, which may be used to distinguish the tetraploid hybrids from hexaploids and octoploids. Tuber yield and flowering intensity were highest in tetraploid hybrids (2n= 4x= 48). Eighteen of the 73 hybrids reached higher yields than the standard variety ‘Adretta’. Floral development and fertility were restored in hybrids derived from fusions between non‐flowering or sterile dihaploids.
Heterotic effects for yield and tuber solids and type of gene action for five traits in 4x potato families derived from interploid (4x‐2x) crosses
Authors: Buso J. A. , Boiteux L. S. , Peloquin S. J.
Published: March 2003

The degree of heterosis for total tuber yield (TTY) and total solids (TS) in 4x‐2x crosses was estimated by comparing the performance of 12 families with their respective parents in two locations in Wisconsin (USA). The parental 2x clones were Phureja‐haploid Tuberosum hybrids with 2n‐pollen production by first‐division restitution. The general combining ability (GCA) and specific combining ability (SCA) were estimated for TTY, TS, vine maturity (VM), length of tuber sprout dormancy (LD), and tuber eye depth (ED). Family performance for TTY ranged from 74 to 146% at Hancock (E#1) and from 77 to 287 at Rhinelander (E#2) when compared with that of the 4x parent group. For VM, the families were late maturing, but a few precocious ones were identified. For TS, the families had heterosis of 5.1% over the 4x parent group. The families had slightly higher ED values than the 4x parents, but families with values within the commercial range were identified. The family average for LD (54 days) was closer to the 2x group (51 days) than to the 4x group (88 days). The direction and magnitude of the parent‐family relationships were variable. The 4x parent TTY was correlated with progeny in E#1 but not E#2. The 2x parent VM had correlation with the offspring at E#2 but not at E#1. The type of gene action had a trait‐specific expression. Significant SCA and GCA variances were observed, suggesting that additive as well as non‐additive genetic effects were operating. The 4x‐2x crosses were able to generate heterotic families for TTY and TS in combination with other useful traits. However, no promising results were found for LD because of the apparent dominance of the short‐dormancy phenotype. This result indicates the need of additional selection and breeding efforts for some specific traits when using S. phureja‐derived germplasm.
Genetic control of seed weight and calcium concentration in chickpea seed
Authors: Abbo S. , Grusak M. A. , Tzuk T. , Reifen R.
Published: March 2003

Chickpea, Cicer arietinum L., is a staple protein source in many Asian and Middle Eastern countries. Hence, the mineral content of its seed, especially that of calcium, is of nutritional importance. Calcium is transported through plants and to legume pods almost exclusively via the xylem stream, with Ca accretion in developing seeds resulting primarily from diffusion of Ca from the adjoining pod wall. Thus, for seeds of differing surface‐to‐mass ratios, Ca concentration is expected to correlate inversely with seed weight. The relationship between seed weight and Ca concentration in chickpea seeds was studied using a range of germplasm and derivatives from crosses between types differing in seed Ca concentration. Among the cultivars tested, low seed mass was associated with high Ca concentration. However, the study of hybrid progeny indicated that seed Ca content was mainly determined by genetic factors other than grain weight genes. This finding may assist in future breeding of high nutritional quality chickpea cultivars.
Quantitative‐genetic parameters of sorghum growth under striga infestation in Mali and Kenya
Authors: Haussmann B. I. G. , Hess D. E. , Reddy B. V. S. , Mukuru S. Z. , Kayentao M. , Welz H. G. , Geiger H. H.
Published: March 2003

To estimate quantitative‐genetic parameters of sorghum for resistance to the hemi‐parasitic weed striga [Striga hermonthica (Del.) Benth.] and for agronomic traits, 36 diallel F2 populations and their nine parental lines were evaluated under severe striga infestation at two locations each in Mali and Kenya. Location means for grain yield ranged from 132 to 254 g/m2. F2 populations outyielded lines on average by 18%. For striga emergence traits, F2 heterosis values ranged from ‐36% to 232% among populations. Genetic and genotype x environment interaction variances of lines and F2s were highly significant for all traits. Broad‐sense heritabilities for areas under striga severity progress curves and grain yield were 0.83 and 0.90 in lines, and 0.81 and 0.89 in F2s, respectively. General and specific combining ability, and their interaction effects with locations were significant for most traits. F2 superiority for grain yield under striga infestation demonstrates the potential merit of heterozygous cultivars in the target areas. Significant genotype x environment interaction entails multilocational testing to identify stable resistance. A combination of resistance with striga tolerance is recommended to breeders.
Genetic analysis of tocopherol content and composition in winter rapeseed
Authors: Goffman F. D. , Becker H. C.
Published: March 2003

The improvement of the nutritional value and the stability properties of rapeseed oil is partly hindered by the lack of information on the genetic control of tocopherols. The objectives of this investigation were to characterize the inheritance of tocopherols by using two factorial mating designs (North Carolina Design II, NCII). The first (NCII‐A) was produced with two sets of nine parents each, one selected for high and the other for low total tocopherol contents. In the second (NCII‐B), each set consisted of six parents, which were either high or low for the α/γ‐tocopherol ratio. Parents and F1 hybrids from both experiments were tested under field conditions in 1998 and 1999 using a completely randomized design with two replications. Only small differences were detected between mean values of parents and F1 hybrids. General combining ability (GCA) variation in both experiments was highly significant (P < 0.01) for all tocopherol traits. Significant specific combining ability (SCA) effects were only detected for a‐tocopherol in NCIIA and therefore for the α‐/γ‐tocopherol ratio. These results indicate that tocopherol contents and composition are controlled mainly by genes with additive effects. Interactions of F1 hybrids and GCA effects with the environment were significant for only tocopherol contents and not for tocopherol composition.
The influence of a spring habit gene, Vrn‐D1, on heading time in wheat
Authors: Kato H. , Taketa S. , Ban T. , Iriki N. , Murai K.
Published: March 2003

The adaptability of wheat cultivars to environmental conditions is known to be associated with a vernalization requirement, that is, spring/winter habit. To clarify the genetic effect of the spring habit gene, Vrn‐D1, on heading time in the field, recombinant inbred lines (RILs) with or without the Vrn‐D1 gene were produced from F2 plants of the cross between ‘Nanbukomugi’ and ‘Nishikazekomugi’, non‐carrier and carrier cultivars of this gene, respectively. Using growth chambers with a controlled temperature and photoperiod, three components of heading time, i.e. vernalization requirement, photoperiodic sensitivity and narrow‐sense earliness (earliness per se), were evaluated in each RIL. RILs with the Vrn‐D1 gene (E lines) showed greatly reduced vernalization requirements and slightly shorter narrow‐sense earliness than RILs without Vrn‐D1 (L lines), although no difference in photoperiodic sensitivity was observed between the two groups. RILs were planted at four different sites in Japan and examined for their heading time in the field. E lines headed significantly earlier than L lines at all locations, indicating that the earliness of E lines is stable in various environmental conditions. These results indicated that spring habit caused by Vrn‐D1 gene, as well as narrow‐sense earliness, was responsible for heading time in the field.
Winter × spring wheat hybridization ‐ a promising avenue for yield enhancement
Authors: Kant L. , Mani V. P. , Gupta H. S.
Published: March 2003

Introgression of the winter gene pool into spring wheat is being considered as one of the strategies to break through the yield plateau. However, little information is available on the combining ability of these two important but distinct groups of wheats in Indian conditions. Therefore, the present study was undertaken to determine the combining ability and gene action of yield and yield attributes in winter × spring wheat crosses. Seventy F1 progenies developed by 14 winter and five spring wheat lines using a line × tester design were evaluated, along with their parents, for yield and yield attributes in a randomized complete block design under field conditions. The mean squares for all the characters studied showed highly significant differences. The mean squares due to female × male interactions were significant for all the characters studied except for grains per ear and grain weight per ear. Additive genetic effects were found to play a key role in controlling the expression of days to heading, plant height and spikelets per ear.‘MV 19’ and ‘Stepniak’/‘Karvuna’ among winter and ‘PBW 65’ among spring wheats were good general combiners for most of the yield attributes studied. The estimates for specific combining ability effects suggested that, although general combining ability (GCA) effects of most winter wheats are either average or poor, their combination can give desirable genotypes with spring wheat parents possessing a high GCA.
New data on the specificity of the root‐knot nematode resistance genes Me1 and Me3 in pepper
Authors: Castagnone‐Sereno P. , Bongiovanni M. , Djian‐Caporalino C.
Published: March 2003

Root‐knot nematodes, Meloidogyne spp., cause severe damage on solanaceous crops, including tomato and pepper. The objective of this study was to test whether nematodes virulent against the tomato Mi resistance gene were able to overcome the Me1 and Me3 resistance genes from pepper. For that purpose, a collection of 22 Meloidogyne arenaria, Meloidogyne incognita and Meloidogyne javanica isolates, avirulent or virulent against the Mi gene, was assembled. The reproduction of each isolate was evaluated on both susceptible and resistant tomato and pepper genotypes in a growth chamber. The Me1 resistance gene controlled all the avirulent and Mi‐virulent nematodes tested, and therefore appears promising for pepper breeding. In contrast, one M. arenaria and two M. incognita virulent isolates were shown to overcome the pepper Me3 resistance gene. These results encourage the testing of a large number of Meloidogyne isolates to evaluate the plant‐nematode interaction, which could have important consequences for the use and management of resistance genes in the field with respect to specificity and durability of the resistance.
Segregation for isozymes and HMW glutenins in a doubled‐haploid cross of winter wheat carrying 1BL.1RS and 5DL.5RS translocations from rye
Authors: Vahl U. , Müller G. , Weber W. E.
Published: March 2003

The doubled haploid (DH) wheat line ‘dh 5841’ carrying two translocations from rye, 5DL.5RS and 1BL.1RS, has been crossed to the subline of wheat cultivar ‘Amadeus 7143’ with a 1BL.1RS translocation. The resulting F1 hybrid IJ 98 with a heterozygous 5DL.5DS‐5DL.5RS chromosome pair has been used to produce doubled haploids. A total of 57 DH lines were obtained from plantlets regenerated in anther culture after successful colchicine treatment and seed set. These lines were identified regarding the constitution of chromosome 5D (5DL.5DS or 5DL.5RS) by means of isoenzyme marker analysis. Thirty DH lines possessed the 5DL.5DS chromosome, while the remaining 27 lines carried the 5DL.5RS translocation. For some of these lines, the 5DL.5RS chromosome was cytologically confirmed by C‐banding. Furthermore, the DH lines were evaluated for their high molecular weight glutenin subunit composition. All possible combinations for the four independent loci —Skdh, Glu‐Al, Glu‐B1 and Glu‐D1— were detected in only 57 DH lines and no segregation distortion was observed.
Genetic analysis of presence and absence of lint and fuzz in cotton
Authors: Du X. M. , Pan J. J. , Wang R. H. , Zhang T. Zh. , Shi Y. Zh.
Published: March 2003

Cotton fibre mutants that were fuzzless and/or lintless were crossed with each other and a normal genotype (fuzzy, linted) to produce F2 and BC1 generations. F2 segregation ratios from the cross of fuzzless‐lintless × fuzzy‐linted, for fuzzy‐linted, fuzzless‐linted and fuzzless‐lintless were 45 : 15 : 4. From the cross of fuzzless‐lintless × fuzzy‐linted, the F2 segregation ratios were 9 : 39 : 16 whereas the BC1F1 segregation ratios from the F1 backcrossed to fuzzless‐lintless were 1 : 3 : 4. These data suggest that the presence or absence of lint and fuzz are controlled by the interaction of four gene loci on non‐homologous chromosomes. We designate these loci as N1, N2, Li3 and Li4, where N1 N1 confers the presence of fuzzy, N2N2 confers inhibition of fuzzy initiation and development, and duplicate gene pairs, Li3Li3 and Li4Li4, determine the presence of lint. Homozygosity for li3li3 and li4li4 might also inhibit fuzz from development. In other words, they were recessive epistatic to fuzz genes.
Chromosomal location of Hwc2, one of the complementary hybrid weakness genes, in rice
Authors: Ichitani K. , Fukuta Y. , Taura S. , Sato M.
Published: March 2003

A hybrid weakness phenomenon is controlled by a set of complementary genes, Hwc1 (hybrid weakness c) and Hwc2, in rice. The Hwc2 gene is prevalent among temperate Japonica but not among tropical Japonica or Indica. In this study, the chromosomal location of the Hwc2 locus was determined from the segregation in the F1 hybrids made between 127 recombinant inbred lines and the cultivar ‘Jamaica’. Hwc2 was located between the two restriction fragment length polymorphism loci, XNpb264 and XNpb197 on chromosome 4. Further analysis indicated that Hwc2 was closely linked to Ph (phenol staining). The genetic and phylogenetic significance of the Hwc2 locus and the surrounding chromosomal region is discussed.
A major quantitative trait locus for resistance to Turnip Yellows Virus (TuYV, syn. beet western yellows virus, BWYV) in rapeseed
Authors: Dreyer F. , Graichen K. , Jung C.
Published: March 2003

Turnip yellows virus (TuYV) is responsible for a recognizable loss of yield in European winter oilseed rape cultivation. To map genes involved in TuYV resistance, a double haploid population was established by crossing a resynthesized rapeseed line (R54) as donor for TuYV resistance with an elite rapeseed line (‘Express’). Resistance was determined with 10 plants per line by double antibody sandwich‐enzyme‐linked immunosorbent assay. After screening 17 primer combinations (Pstl/Msel and EcoRI/Msel), 143 amplified fragment length polymorphism markers were mapped to 20 linkage groups representing 15 chromosomes of the rapeseed genome. Quantitative trait loci (QTL) were mapped using the composite interval mapping approach. As a result, one major quantitative trait locus was found on linkage group MS17, explaining up to 50% of the phenotypic variation. Because no other factors displaying a significant effect on the expression of resistance could be identified, a simple mode of inheritance for TuYV resistance is suggested, thus enabling marker‐assisted selection during rapeseed breeding.
The effect of indirect tests for grain quality on the grain yield and industrial quality of bread wheat
Authors: Trethowan R. M. , Pena R. J. , Van Ginkel M.
Published: March 2003

The objective of this study was to examine the effect of selection using three indirect tests for grain quality on grain yield and dough, and baking properties, measured as alveograph strength, alveograph tenacity/extensibility ratio and loaf volume. The three tests were flour protein content, flour sedimentation and high molecular weight glutenin subunits. Of the indirect tests used for grain quality, sodium dodecyl sulphate (SDS)‐sedimentation allowed the highest intensity of selection for a combined trait index of the target grain quality and grain yield characteristics. The top 48% of the material could be retained on the basis of SDS‐sedimentation, resulting in retention of atleast two‐thirds of the top 10% of genotypes for the combined trait index. Flour protein percentage, a weighted high molecular weight glutenin index and an index combining all the indirect tests—flour protein, SDS‐sedimentation and high molecular weight glutenins—gave selection intensities of 61%, 64% and 55%, respectively, for the combined trait index. If the objective of selection is dough strength alone, then a weighted index of all indirect traits (flour protein, SDS‐sedimentation and high molecular weight glutenins) provided the highest selection intensity (26%). Other selection intensities for individual target traits were 24% for the prediction of loaf volume from flour protein, 40% for the prediction of tenacity/ extensibility ratio using SDS‐sedimentation and 68% for the prediction of grain yield using SDS‐sedimentation.
Genetic base and diversity in groundnut genotypes
Authors: Badigannavar A. M. , Kale D. M. , Murty G. S. S.
Published: March 2003

For the last four decades, genetic improvement of groundnut by induced mutation and recombination breeding at the Bhabha Atomic Research Centre, Trombay, Mumbai, India, has led to the isolation of 61 distinct genotypes, of which eight have been released for commercial cultivation. The present study was undertaken to quantify the genetic base and study the diversity through coefficient of parentage and cluster analysis. Eight ancestors have contributed to the entire genetic base, and of these ‘Spanish Improved’, through its induced mutants and mutant derivatives, accounts for 67.7% coefficient of parentage, leading to a narrow genetic base. However, the genotypes used in this study exhibited considerable variability for vegetative, reproductive and agronomic traits. Cluster analysis indicated no relationship between clustering pattern and subspecies among genotypes during rainy or summer seasons. Despite this narrow base, greater diversity could be possible following judicious use of mutation and recombination breeding to bring about genetic improvement.
Nitrogen uptake and utilization efficiency of European maize hybrids developed under conditions of low and high nitrogen input
Authors: Presterl T. , Groh S. , Landbeck M. , Seitz G. , Schmidt W. , Geiger H. H.
Published: March 2003

Maize varieties with improved nitrogen(N)‐use efficiency under low soil N conditions can contribute to sustainable agriculture. Tests were carried to see whether selection of European elite lines at low and high N supply would result in hybrids with differential adaptation to these contrasting N conditions. The objective was to analyze whether genotypic differences in N uptake and N‐utilization efficiency existed in this material and to what extent these factors contributed to adaptation to low N supply. Twenty‐four hybrids developed at low N supply (L × L) were compared with 25 hybrids developed at high N supply (H × H). The N uptake was determined as total above‐ground N in whole plants, and N‐utilization efficiency as the ratio between grain yield and N uptake in yield trials at four locations and at three N levels each. Highly significant variations as a result of hybrids and hybrids × N‐level interaction were observed for grain yield as well as for N uptake and N‐utilization efficiency in both hybrid types. Average yields of the L × L hybrids were higher than those of the H × H hybrids by 11.5% at low N supply and 5.4% at medium N level. There was no significant yield difference between the two hybrid types at high N supply. The L × L hybrids showed significantly higher N uptake at the low (12%) and medium (6%) N levels than the H × H hybrids. In contrast, no differences in N‐utilization efficiency were observed between the hybrid types. These results indicate that adaptation of hybrids from European elite breeding material to conditions with reduced nitrogen input was possible and was mainly the result of an increase in N‐uptake efficiency.
Indica‐Japonica differentiation of paddy rice and its relationship with heterosis
Authors: Sun C. Q. , Jiang T. B. , Fu Y. C. , Wang X. K.
Published: March 2003

The Indica‐Japonica differentiation of three photoperiod‐sensitive and/or thermosensitive genetic male‐sterile rice (PGMS or TGMS, respectively) lines and 47 male parental lines from seven ecotypes were studied for their restriction fragment length polymorphism marker data to determine which ecotype crosses with the three PGMS and/or TGMS lines could lead to higher yield potential, and to estimate the relationship between the Indica‐Japonica differentiation of parents and heterosis in grain yield and its components. The results indicated that hybrids derived from ‘N422s’ and the early‐middle ripening Indica varieties from southern China, and hybrids between ‘Pei'ai64s’ and three Japonica ecotypes, including North‐eastern Japonica varieties, restoring lines of Japonica hybrid rice and north China Japonica varieties, showed the highest grain yields. There was less variation of yield among the F1s between ‘108s’ and the seven ecotypes than among the other F1s. Highly significant positive correlations between heterosis of the F1 yield and genetic distance of the parents were detected, although the correlation between F1 yield performance and genetic distance did not reach a significant level. Considerable variation of correlation between heterosis and genetic distance was also detected in the Indica × Indica crosses and Indica × Japonica crosses. There was much higher correlation (r = 0.63) between the F1 yield performance and the genetic distance of parents in the Indica × Indica crosses than in the others. It is proposed that a genetic distance of 0.4‐0.8 between the two parents of hybrid rice might be appropriate not only for F1 performance, but also for heterosis.
Comparison of two fertility restoration systems against photoperiod‐sensitive cytoplasmic male sterility in wheat
Authors: Murai K.
Published: March 2003

A ‘two‐line system’ using photoperiod‐sensitive cytoplasmic male sterility (PCMS) caused by Aegilops crassa cytoplasm under a long‐day photoperiod ( 15 h) has been proposed as a new means of producing hybrid varieties in common wheat. The PCMS line is maintained by self‐pollination under short‐day conditions, and hybrid seeds can be produced through outcrossing of the PCMS line with a pollinator under long‐day conditions. Two kinds of fertility restoration systems against the PCMS are known. One is involved with a set of multiple fertility‐restoring (Rf) genes in the wheat cultivar ‘Norin 61’ located on (at least) chromosomes 4A, 1D, 3D and 5D. The other is controlled by a single dominant major Rf gene, Rfd1, located on the long arm of chromosome 7B in the wheat cultivar ‘Chinese Spring’. To examine the degree of fertility restoration by these two systems, nine PCMS lines were crossed with ‘Norin 61’ and ‘Chinese Spring’ as the restorer lines, and the F1 hybrids were investigated. The degree of fertility restoration was estimated by comparing the seed set rates in the F1 hybrids having the Ae. crassa cytoplasm and those with normal cytoplasm. The results revealed that the fertility restoration ability of a set of multiple Rf genes in ‘Norin 61’ was higher than that of the Rfd1 gene in ‘Chinese Spring’.
Genetic variation, heritability and progeny testing in meadow bromegrass
Authors: de Araüjo M. R. A. , Coulman B. E. , Rakow G.
Published: March 2003

Meadow bromegrass is a recently introduced pasture grass in western Canada. Its leafy production and rapid regrowth have made it a major grass species for pasturing beef animals in this region. Because relatively little breeding work has been done on this species, there is little information on its breeding behaviour. The main objective of this study was to estimate genetic parameters and assess breeding methodologies for meadow bromegrass. Forty half‐sib (polycross and open‐pollinated) and full‐sib (selfed) progenies were evaluated for dry matter and seed yield, fertility index, harvest index, plant height, plant spread, crude protein, neutral detergent fibre and acid detergent fibre. Genetic variation for seed yield, harvest index, and plant height was significant in the open‐pollinated and selfed tests. Genetic variation estimates for dry matter yield were negative (polycross), not significant (open‐pollinated), or significant (selfed). Estimates of genetic variation for quality traits were not significant, except for acid detergent fibre (selfed). Correlations among characters indicated that it is possible to simultaneously improve seed and forage yield. Rankings of progenies by the half‐sib tests for forage and seed yield were not altered by the use of the synthetic parental value (SVi), which includes information from selfed progeny. The polycross progeny test did not discriminate parents as well as the open‐pollinated and selfed tests; this may have been a result of non‐random pollination in the polycross. Correlation among the progeny tests, showed that open‐pollinated and selfed progeny tests agreed for all characters, except for harvest index, while correlation between polycross and selfed tests were significant for six characters but not dry matter yield, and acid and neutral detergent fibres. The most dissimilar tests were polycross and open‐pollinated, with significant correlations found only for fertility index, height, spread and neutral detergent fibre. It was concluded that there was significant variation and moderate heritability for most traits in the meadow bromegrass populations evaluated, and that the open‐pollinated progeny test is the method of choice for selecting parents for synthetics of this species.
Gross Morphometry of the Bovine Placentome during Gestation
Authors: Laven RA , Peters AR
Published: March 2003

Forty‐seven pregnant uteri were collected from an abattoir at eight chronological stages of gestation. Assessments were made of placentome number, weight, length shape and ratio of foetal to maternal tissue by weight. The study showed that there was a great variation in number, size, weight and shape of placentomes. There was no significant change in the total number of placentomes during gestation. Both mean weight and length increased significantly during gestation, but there was a significant change in the relationship between the two as gestation progressed. There was no correlation between the number of placentomes and the mean weight or length of the placentomes. The development of the placenta in the non‐pregnant horn was significantly different from that of the pregnant horn, with fewer, smaller, lighter placentomes. However, there was no evidence that placentome development in the non‐pregnant horn was affected by placentome development in the pregnant horn. The proportion of the placentome that was maternal tissue increased during gestation, but there was no significant effect of placentome number, or individual placentome weight or length on this proportion. Two placentome shapes were identified, but no effect on foeto‐maternal proportion or relationship between shape and total placentome number or weight was identified.
Intraperitoneal Insemination in Mammals: A Review
Authors: Yaniz JL , Lopez‐Bejar M , Santolaria P , Rutllant J , Lopez‐Gatius F
Published: March 2003

Contents

This review focuses on factors associated with the development of intraperitoneal insemination in mammals. Findings to date indicate that fertility improves as the sperm cell concentration rises, but that the optimal sperm number differs in each species. Sperm washing before intraperitoneal insemination favours fertility. Peritoneal fluid shows a variable effect on spermatozoa, depending on the hormonal status of the female. The optimal time for insemination appears to be just prior to ovulation. The technique may be performed either through the abdominal or the vaginal wall. Verification of sperm deposition in the proximity of the ovaries improves fertility rates. Although associated with some risk of infection and an immune reaction against spermatozoa, the intraperitoneal technique rarely gives rise to severe anaphylactic shock, peritonitis, adhesion formation and the production of anti‐sperm antibodies and these complications may be prevented by adequate sperm pretreatment and antibiotic therapy. The success of intraperitoneal insemination in humans, with results comparable with those of intrauterine insemination in the treatment of infertility, suggest the potential use of this technique in domestic mammals, especially in those in which intrauterine insemination poses practical difficulties. Some of the methods applied in human intraperitoneal insemination, such as confirming the position of the needle in the peritoneal cavity, and sperm pre‐treatments might also improve results in domestic species. Conversely, the use of the animal model should help to develop some aspects of this technique in humans.
Antigen‐specific lymphocytes enhance nitric oxide production in Mycobacterium bovis BCG‐infected bovine macrophages
Authors: Carpenter Elizabeth , Fray Linley , Gormley Eamonn
Published: March 2003

Nitric oxide (NO) production was evaluated in macrophages isolated from Mycobacterium bovis bacille Calmette‐Guérin (BCG)‐immunized, and control non‐immunized, cattle. Incubation of M. bovis BCG‐infected macrophages with recombinant bovine IFN‐γ led to increased nitrite levels in culture supernatants. It was also demonstrated that NO production by autologous M. bovis BCG‐infected macrophages increased in a linear relationship with the number of antigen‐specific lymphocytes added to cultures. The elevated NO levels were also associated with increased IFN‐γ secretion. Treatment of cultures with the NO inhibitor, N‐monomethyl l‐arginine (L‐NMMA), reduced the levels of NO without affecting the metabolic activity of internalized M. bovis BCG. Our results suggest that synthesis of NO may constitute an integral part of the cell‐mediated antigen‐specific response against M. bovis BCG. However, although the presence of lymphocytes does partially inhibit multiplication of M. bovis BCG in macrophages, it appears that the activity of NO, or the levels produced in monocyte‐derived macrophages, may be insufficient to influence the growth of the intracellular mycobacteria.
The in vivo balance between B cell clonal expansion and elimination is regulated by CD95 both on B cells and in their micro‐environment
Authors: Rathmell Jeffrey C , Goodnow Christopher C
Published: March 2003

The expression of CD95 (Fas/APO‐1) on B cells has been shown to play a direct role in their fate. B␣cells that chronically bind antigen due to prolonged antigen exposure, such as self‐reactive B cells, are induced to express CD95 by CD40 ligand (CD40L) and are subsequently eliminated by CD95 ligand (CD95L) when they present antigen to CD4+ T cells. B cells that bind antigen acutely due to sudden antigen encounter, such as foreign antigen reactive B cells, up‐regulate CD95, but are normally protected from CD95L‐mediated apoptosis. Here, however, it is shown in vivo that foreign antigen‐specific B cells fail to be protected from CD95‐dependent elimination in a host that is CD95 deficient, regardless of antigenic challenge. These data indicate that B cell antigen receptor (BCR)‐induced protection against CD95L‐mediated apoptosis is not absolute but depends upon other micro‐environmental factors in vivo. The normal balance between T cell‐dependent humoral immunity and tolerance is thus regulated intrinsically by CD95 expression on responding B cells, and extrinsically by CD95‐mediated control of CD95L or other molecules in the lymphoid micro‐environment.
Effect of IL‐4 deletion on cardiac allograft survival in the BALB/c to 129Sv × C57BL/6 strain combination
Authors: Mottram PL , Murray‐Segal LJ , Li YQ , Han W‐R , Sandrin M , McKenzie Ian FC
Published: March 2003

To investigate the effect of IL‐4 deletion on cardiac allograft survival, vascularized BALB/c cardiac allografts were placed in C57BL/6, 129Sv × C57BL/6 (IL‐4 +/+) or 129Sv × C57BL/6 IL‐4 knockout mice (IL‐4−/−). Untreated recipients rejected allografts in < 15 days while isografts survived indefinitely (> 100 days). Treatment with anti‐CD4 (GK1.5) for 4 days at the time of allografting increased mean survival to > 100 days in C57BL/6, 90±16 days in 129Sv × C57BL/6 (IL‐4 +/+) and 68 ± 36 days in 129Sv × C57BL/6 (IL‐4−/−) recipients. Although there was a trend towards shorter survival times in the IL‐4−/− mAb‐treated mice, survival in the three recipient groups was not significantly different (P = 0.07). A 30‐day course of anti‐CD4 did not further prolong BALB/c heart survival. All long‐surviving hearts had histological evidence of parenchymal damage and transplant vascular disease. None of these recipients developed antigen‐specific tolerance, since both donor and third party skin graft challenges were rejected when challenged at> 60 days post‐graft and all primary grafts failed by 120 days. Thus the effects of IL‐4 deletion were subtle and were seen only with low doses of immunosuppression in this high responder strain combination.
Involvement of ribosomal proteins in regulating cell growth and apoptosis: Translational modulation or recruitment for extraribosomal activity?
Authors: Naora Honami , Naora Hiroto
Published: March 2003

Gene recruitment is a mechanism of molecular evolution whereby a gene product can function in more than one distinct capacity. The ‘one gene–dual function’ phenomenon is well illustrated by crystallins, structural proteins that play both specialized roles in the eye lens and also ‘housekeeping’ enzyme roles. Ribosomal proteins are integral components of the basal cellular machinery involved in protein synthesis, whose roles have been regarded collectively as important, but individually somewhat mundane. However, various individual ribosomal proteins and also translation initiation and elongation factors have been found to play roles in regulating cell growth, transformation and death, giving rise to increasing speculation that components of the translational apparatus can act as multifunctional proteins. Recently, we have shown that ribosomal protein S3a (RPS3a) plays important roles in cell transformation and death, whereby constitutively or transiently enhanced RPS3a expression can be regarded as ‘priming’ a cell for apoptosis and suppression of such enhanced expression as ‘execution’. While it is unclear whether RPS3a acts in a capacity mechanistically distinct from that in translation, such a possibility is discussed in this article in the light of recent, although not exhaustively reviewed, findings implicating the involvement of other individual ribosomal proteins in modulating and/or effecting changes in cellular responses and growth patterns in an extraribosomal capacity independent of their conventional role in translation.
Activation‐induced apoptosis of autoreactive and alloreactive T lymphocytes in the target organ as a major mechanism of tolerance
Authors: Pender Michael P
Published: March 2003

Normal individuals have mature T lymphocytes that are capable of reacting to self‐antigens and can be activated by cross‐reacting environmental antigens. The mechanism that maintains immune tolerance and prevents these activated autoreactive T cells from causing autoimmune disease is unclear. We have previously hypothesized that activation‐induced apoptosis of previously activated autoreactive T cells in the target organ is a major mechanism for maintaining tolerance. Here I review the current evidence to support this hypothesis. It is proposed that when activated autoreactive T cells enter the target organ, they are reactivated mainly by non‐professional antigen‐presenting cells (APC) and deleted by activation‐induced apoptosis through the Fas (CD95) pathway before producing significant target organ damage. This apoptosis occurs because the reactivated T cells do not receive sufficient costimulation from the non‐professional APC to up‐regulate their expression of Bcl‐2‐related anti‐apoptotic proteins, which inhibit the CD95 pro‐apoptotic pathway. This is in contrast to the situation in peripheral lymphoid organs, where reactivation of T cells by professional APC results in sufficient costimulation‐induced up‐regulation of Bcl‐2‐related proteins to inhibit the CD95 pathway and allow T cell proliferation and survival as memory T cells. Activation‐induced apoptosis of alloreactive T cells in allografts can similarly account for spontaneous allograft acceptance, as occurs after MHC‐mismatched liver transplantation.
The peripheral lymphoid compartment is disrupted in flaky skin mice
Authors: Abernethy Nevin J , Hagan Colin , Tan Paul Lj , Birchall Nicholas M , Watson James D
Published: March 2003

Flaky skin (fsn) is an autosomal recessive mutation on mouse chromosome 17 that causes severe anaemia, forestomach papillomatosis and a papulosquamous skin disease that resembles psoriasis in humans. In the present paper, it is reported that fsn causes peripheral lymphadenopathy, CD4/CD8 imbalance and hyperresponsiveness to T cell growth factors. Peripheral lymph nodes (PLN) of adult mutant (fsn/fsn) mice were found to contain almost 10‐fold more leucocytes than PLN from phenotypically normal littermates (+/fsn or +/+, hereafter referred to as +/?). Analysis of PLN cells using mAbs and flow cytometry revealed that this predominantly lymphoid hyperplasia was characterized by approximately equivalent increases in the numbers of CD3+ T cells and CD19+ B cells. However, expansion within the T cell compartment was non‐random, because fsn/fsn PLN had a considerably reduced ratio of CD4+ to CD8+ T cells (1.08 ± 0.37) compared to +/? PLN (2.47 ± 0.44, P < 0.0001). In vitro assays of cellular proliferation in response to T and B cell growth factors showed that fsn/fsn PLN cells were hyperresponsive to IL‐2, IL‐4 and IL‐7 when compared with PLN cells from +/? mice. Studies using mesenteric lymph node and peripheral blood cells showed that hyperresponsive cells are widely distributed in fsn/fsn mice. Experiments in newborn mice showed that the lymphoid disturbances caused by fsn are established at least as early as 2 weeks of age, a time that precedes the onset of the earliest clinical skin lesions. These data implicate a role for the fsn gene product in regulating the size and content of the peripheral lymphoid compartment.
Partial T cell activation with an altered superantigenic ligand
Authors: Hayball John D , Lake Richard A
Published: March 2003

T cells have the capacity to respond to ligands as full, weak, partial or null agonists, or indeed as antagonists. In the present paper, it is reported that staphylococcal enterotoxin B (SEB) mutated in a T cell receptor (TCR) contact site (SEBΔ61Y) behaves as an altered ligand for a T cell clone (AC20) that expresses the Vβ17 TCR. The T cells were partially activated by SEBΔ61Y, as shown by TCR down‐modulation and up‐regulation of the IL‐2 receptor. However, these cells did not secrete IL‐2, IL‐3, IL‐4 or IFN‐γ, nor did they proliferate. Analysis of intracellular protein tyrosine phosphorylation after cellular activation provided further evidence that SEBΔ61Y could transduce a signal via the Vβ17 TCR. The events following receptor ligation were clearly different when the T cells were stimulated with SEB or SEBΔ61Y, manifested as both quantitatively and qualitatively different patterns of phosphorylation of intracellular substrates. In contrast, only quantitative differences were apparent when a transfectant expressing the same α/β TCR was stimulated with the different superantigens. Together, these results provide the first demonstration that altered TCR ligands are not restricted to peptides substituted at secondary TCR contact residues. Rather, an altered superantigenic ligand mutated in the TCR binding site can behave as a partial agonist.
Absence of lipopolysaccharide high‐dose paralysis in B‐cell responses: Implications for the one‐signal theory
Authors: Mamchak Alusha A , Hodgkin Philip D
Published: March 2003

Over 20 years ago, Coutinho and Möller reported that high concentrations of LPS were paralytic for the development of antibody secreting cells (ASC). This data was used to explain bell‐shaped dose–response curves observed for antihapten antibody formation in response to haptenated LPS. In turn, this bell curve was used to formulate the one‐signal model of B cell activation, which argued that antigen signalling was generally unimportant to B cell responses. The present paper re‐examines LPS dose–response curves and finds results that do not support the view that high doses of LPS inhibit B cell differentiation to ASC. If high‐dose paralysis is not an attribute of LPS stimulation, then the bell‐shaped dose curve for hapten‐specific ASC originally observed by Coutinho and Möller required an alternative explanation. Through the use of haptenated Ficoll, it was possible to show that the generation of LPS‐induced antitrinitrophenol ASC could be inhibited by antigen presented on an inert substrate. Thus, the transmission of surface Ig‐mediated (antigen) signals at higher concentrations can explain the antihapten bell‐shaped dose curves, in contradiction to the conclusions of the one‐signal model.
Signalling organelle for retrograde axonal transport of internalized neurotrophins from the nerve terminal
Authors: Sandow SL , Heydon K , Weible MW , Reynolds AJ , Bartlett SE , Hendry IA
Published: March 2003

The retrograde axonal transport of neurotrophins occurs after receptor‐mediated endocytosis into vesicles at the nerve terminal. We have been investigating the process of targeting these vesicles for retrograde transport, by examining the transport of [125I]‐labelled neurotrophins from the eye to sympathetic and sensory ganglia. With the aid of confocal microscopy, we examined the phenomena further in cultures of dissociated sympathetic ganglia to which rhodamine‐labelled nerve growth factor (NGF) was added. We found the label in large vesicles in the growth cone and axons. Light microscopic examination of the sympathetic nerve trunk in vivo also showed the retrogradely transported material to be sporadically located in large structures in the axons. Ultrastructural examination of the sympathetic nerve trunk after the transport of NGF bound to gold particles showed the label to be concentrated in relatively few large organelles that consisted of accumulations of multivesicular bodies. These results suggest that in vivo NGF is transported in specialized organelles that require assembly in the nerve terminal.