bluuebunny/crossref_metadata_2025 huggingface dataset:
THE GENIC BASIS FOR DIFFERENCES IN SEDIMENTATION VALUE AND PROTEIN CONTENT BETWEEN TWO CULTIVARS OF TRITICUM AESTIVUM
Authors: Wu K. K. , Sosulski F. W. , Wehrhahn C. F.
Published: November 2014

Genie analysis was used to study the inheritance of sedimentation value and protein content in two sets of reciprocal inbred backcross lines. Three loci containing genes with major effects were responsible for most of the differences in sedimentation value between two wheat cultivars, Baart and Ramona, grown in two years. These loci accounted for 84% to 93% of genetic variation, while environmental variances were relatively low. However, the differences in protein content between the two parents were too small for the present technique to detect the presence of any major genes. No genetic relationship was found between protein content and sedimentation value.
INVITATION PAPER: THE SEARCH FOR RELEVANT SHORT TERM BIOASSAYS FOR CHEMICAL CARCINOGENS: THE TRIBULATION OF A MODERN SISYPHUS
Authors: Stich H. F. , Lam P. , Lo L. W. , Koropatnick D. J. , San R. H. C.
Published: November 2014

Based on a good correlation between carcinogenicity and mutagenic activity several rapid microbial bioassays for chemical carcinogens have been recently developed. We would like to suggest, that these microbial tests should be followed by bioassays using cultured human cells of the "average" man, and of persons with elevated cancer risk or increased susceptibility to carcinogenic agents. The main objective of using DNA repair (unscheduled uptake of3HTdR) and DNA fragmentation (shift in sedimentation profiles) of cultured human cells was to design a test system that can simulate conditions found in man and thus provide information relevant to the human population. A trial on 98 different carcinogens, precarcinogens and noncarcinogens showed the suitability of DNA repair synthesis as a rapid, economic and relevant assay for detection of chemical carcinogens. To check the adaptibility of DNA repair synthesis of human cells as a bioassay for chemical carcinogens we examined carcinogenic nitrosation products which are formed from the interaction of nitrite and nitrosatable compounds, carcinogenic or mutagenic photosensitizing chemicals, and the effect of complex interactions. Organotropic carcinogens can be detected by measuring DNA fragmentation and DNA repair in various target organs following the in vivo application of chemical carcinogens. The pros and cons of several bioassays and their usefulness in judging a carcinogenic or mutagenic hazard to human populations is discussed.
DETECTION OF VIRUS-LIKE PARTICLES IN THE COREMIA OFPENICILLIUM CLAVIFORME
Authors: Lai H. C. , Zachariah K.
Published: November 2014

A double-stranded ribonucleic acid (dsRNA) was isolated from coremial extracts of wild type P. claviforme, by methylated-albumin kieselguhr chromatography. Differential centrifugations of the coremial extracts from WT and Sh mutant strains yielded two classes of virus-like particles (VLP), of dimensions 25-30 nm, and 50-70 nm. The possible ecological significance of fungal viruses is discussed.
GENETIC ANALYSIS OF A POPULATION OF TRIBOLIUM. V. VIABILITY OF THE UNSATURATED FATTY ACID SENSITIVE MUTANT
Authors: Scully A. M. M. , Costantino R. F.
Published: November 2014

The viability pattern of the unsaturated fatty acid sensitive mutant (cos/cos) of Tribolium castaneum was examined with reference to the normal genotype from egg hatching through adult emergence. The beetles were cultured on diets with 0, 3, or 5% corn oil in growth chambers maintained at 33 ± 1 °C and either 42 ± 6% or 75 ± 3% relative humidity. The pattern of the mutant was altered during the larval stage and was dependent on both the concentration of dietary fatty acid and the relative humidity of the culture chamber.Values of the viability component of fitness were assigned to the cos/cos, ±/cos and ±/± genotypes for multiple environments based on the number of eggs surviving to pupation. In large, random mating populations segregating at this locus, a stable genetic polymorphism is forecast. Predicted rates of change of allele frequency are dependent upon the culture conditions.
THE DIFFERENCE OF PUPA WEIGHT MEASUREMENTS IN TRIBOLIUM AND ITS EFFECTS ON SELECTION RESPONSES
Authors: Yamada Yukio
Published: November 2014

Possible causes of asymmetrical direct and indirect selection responses in Tribolium which were observed in a series of various experiments have been investigated. In some experiments the pupae were weighed just after pupation and in others they were weighed on the 20th day of incubation. Weight loss between pupation time and the 20th day of incubation as well as systematic differences in weight between individuals pupating at successive ages are considered to be responsible for the asymmetry. The concept of unconscious secondary selection was introduced to interpret the asymmetries of realized heritability and genetic correlation observed in two-way selection experiments.
GENIC ANALYSIS FOR ACID PHOSPHATASE ISOZYMES INORYZA PERENNISANDO.SATIVA
Authors: Pai Chiang , Endo T. , Oka H. I.
Published: November 2014

It was concluded from genetic experiments that various acid phosphatase zymograms observed among the rice strains belonging to Oryza perennis Moench (wild) and O. sativa L. (cultivated) were controlled by alleles at three loci, Acp1, Acp2, and Acp3. At Acp1seven codominant alleles were found each producing a group of three major (A, M, and C) and three minor (a, m, and c) bands on starch gel. The alleles determined mobility of the band group. Statistical analysis of the data taken from densitometric tracings of zymograms indicated that hybrids between strains with different mobilities would produce three major and three minor hybrid bands each occurring between two corresponding parental bands. In addition, a null form lacking all these bands was found that had a recessive allele, Acp1Nu1. The Acp1locus was independent of Px1(specifying peroxidase OC, 2A, and 4A bands), but was linked withPx2(specifying peroxidase 4C band). The Acp2locus carried two codominant alleles specifying bands Fa and Sa, respectively, and a recessive silent allele, Acp2Nu1. This locus was closely linked with Acp1, yet it was distinguished from the latter as different allelic combinations were observed among parental strains. At Acp3alleles specifying bands B and b were found which were peculiar to O. perennis subsp. barthii; other perennis and sativa strains appeared to have their recessive silent alleles.
GENETICS OF STEM RUST RESISTANCE IN WHEAT CULTIVARS ROMANY, Es.P 518/9, BONNY AND TAMA
Authors: Dyck P. L. , Green G. J.
Published: November 2014

The genetics of resistance to stem rust (Puccinia graminis tritici) was investigated in wheat (Triticum aestivum L.) cultivars Romany, Es.P 518/9, Bonny and Tama that are resistant to many races in both Canada and Kenya. Seedling resistance in the four cultivars to 12 Canadian races is controlled primarily by previously identified genes. The results indicate that the cultivars have the following genes: Romany — Sr5, Sr6, Sr7a, Sr9b and SrW; Es.P 518/9 — Sr5, Sr6, Sr7a, Sr8, Sr9b, SrW and possibly Sr17; Bonny — Sr6 and Sr11; and Tama — Sr6 and Sr8. Gene SrW confers moderate resistance and is also present in the cultivar Webster.
EVIDENCE FOR NUCLEAR RESTRICTION OFSUPERSUPPRESSORGENE PRODUCTS INNEUROSPORAHETEROKARYONS
Authors: Griffiths A. J. F.
Published: November 2014

It was demonstrated that the gene products of the three ssu loci cannot enter the transcription/translation system coded by the other component nucleus in a heterokaryon. In such a situation, dominance or recessiveness cannot be established, and simple dominance tests are meaningless.
THE GENETICS OF BLACK LARVA, AN AUTOSOMAL RECESSIVE LETHAL MUTATION LOCATED ON CHROMOSOME 3 IN THE MOSQUITO ANOPHELES ALBIMANUS
Authors: Rabbani M. G. , Seawright J. A. , Kitzmiller J. B.
Published: November 2014

A spontaneous autosomal recessive lethal mutation, black larva (bl), producing black pigmented larvae that die during the 4th larval instar has been discovered in the mosquito Anopheles albimanus Wiedemann. Genetic investigations using two Y-autosome translocations and a 3rd chromosome dominant marker, St, indicate that bl is located on chromosome 3 at a distance of 15 map units from St.
GENETICALLY CONTROLLED CHROMOSOME BREAKAGE AS AN ISOLATION BARRIER IN THE ORIGIN AND MAINTENANCE OF SECALE ANCESTRALE
Authors: Stutz Howard C.
Published: November 2014

Meiosis in hybrids derived from crosses of Secale ancestrale Zhuk. with related species is highly irregular: chiasmata fail to terminalize; numerous AI and AII bridges form but are usually unaccompanied by fragments; acentric fragments without true bridges are left behind at AI and AII; numerous micronuclei are produced at TII. These anomalies appear to be the result of genetically induced subchromatid exchanges. This appears to be a mechanism established by natural selection for reproductive isolation, thereby permitting this narrowly endemic species to successfully continue in sympatric association with closely related species.
FAILURE TO OBSERVE MITOTIC RHYTHMICITY IN ALLIUM MERISTEMS
Authors: Erickson Susan M. , Hillman William S.
Published: November 2014

Circadian rhythms clearly affect cell division in certain microorganisms and some animal tissues, but reports on mitotic rhythmicity in higher plants are contradictory, even for Allium cepa, the most widely studied material. Mitotic index was determined on root and shoot meristems of seedlings of one cultivar, and on roots of bulbs of another. Various times with respect to 24-h cycles of alternating light and darkness, or light-high temperature and darkness-low temperature were investigated. No evidence for rhythmicity was obtained.
C- AND G-BANDS OF THE OPOSSUM CHROMOSOMES: TERMINAL SEQUENCES OF DNA REPLICATION
Authors: Sinha Anil K. , Kakati Surabhi
Published: November 2014

The sex chromosomes of the opossum, Didelphys virginiana, are the only elements that exhibit C-banding. In contrast, the sex chromosomes as well as the autosomes bear specific G-Bands. However, unlike other mammalian species different types of G-banding are observed if the chromosomes are pretreated with trypsin and SSC solution. The SSC pretreated chromosomes show discrete bands only when stained with Giemsa at certain pH values. An asynchronous pattern of terminal DNA replication is observed among the three C-banding regions of the X-chromosome. The inter- and intrapositive G-banding areas of the chromosomes are not always late in DNA replication in comparison to those negatively stained G-banding areas.
GENES FOR VERNALIZATION RESPONSE IN HOMOEOLOGOUS GROUP 5 OFTRITICUM AESTIVUM
Authors: Halloran G. M.
Published: November 2014

The altered vernalization response of normal Chinese Spring caused by the three individually-substituted chromosomes of homoeologous group 5 of Hope in Chinese Spring was found to be controlled by a single gene on each chromosome. The alleles on chromosomes 5A and 5B of Hope are dominant to those on their respective homologues in Chinese Spring for lowered vernalization response, while that on Hope 5D is dominant to that on Chinese Spring 5D for increased vernalization response. The possibility has been discussed of the vernalization response locus on Hope 5D bearing a null allele or an allele with very little involvement in the vernalization process, in which case the strong vernalization response exhibited by Chinese Spring/Hope 5D could merely be a function of genes promoting vernalization response in the rest of the Chinese Spring genotype.
INDUCED POLYGENIC VARIATIONS IN RELATION TO GENE ACTION FOR YIELD AND YIELD COMPONENTS IN SPRING WHEAT
Authors: Singh R. B. , Sharma G. S.
Published: November 2014

Gene action in relation to yield per plant, 1000-grain weight and number of grains per spike was studied in 9 × 9 diallel F1 and F2 populations derived separately from nine elite diverse normal and EMS treated spring wheat cultivars (Triticum aestivum L.em Thell.). Some additive and all dominance components were significant for the three characters, their relative proportions varied from character to character. Preponderance of additive gene action was revealed for 1000-grain weight, whereas prevalence of nonadditive gene action was noted for grain yield and number of grains per spike. The magnitude of the additive component increased considerably in EMS treated F2 populations for 1000-grain weight and grain yield, whereas the EMS treatment increased the proportion of nonadditive components for number of grains per spike. Breeding plans which may effectively exploit both additive and nonadditive components of variances for evolving superior breeding populations of spring wheat have been suggested.
GENETIC EFFECTS OF FEEDING IRRADIATED WHEAT TO MICE
Authors: Vijayalaxmi
Published: November 2014

The effects of feeding irradiated wheat in mice on bone marrow and testis chromosomes, germ cell numbers and dominant lethal mutations were investigated. Feeding of freshly irradiated wheat resulted in significantly increased incidence of polyploid cells in bone marrow, aneuploid cells in testis, reduction in number of spermatogonia of types A, B and resting primary spermatocytes as well as a higher mutagenic index. Such a response was not observed when mice were fed stored irradiated wheat. Also there was no difference between the mice fed un-irradiated wheat and stored irradiated wheat.
LOCALIZATION OF GIEMSA BANDS IN LOTUS PEDUNCULATUS CHROMOSOMES
Authors: Shankland N. Everts , Grant W. F.
Published: November 2014

Giemsa staining elicited pericentromeric and telomeric bands in Lotus pedunculatus Cav. chromosomes. All chromosomes were readily distinguishable by the size and location of their bands. In several instances the bands correlated with heterochromatically condensed chromatin. Connectives between prophase telomeres were also observed.
FUSION OF CARROT AND BARLEY PROTOPLASTS AND DIVISION OF HETEROKARYOCYTES
Authors: Dudits D. , Kao K. N. , Constabel F. , Gamborg O. L.
Published: November 2014

Fusion of protoplasts from cultured cells of carrot (Daucus carota L.) and from leaves of barley (Hordeum vulgare L.) by means of polyethylene glycol resulted in the formation of 4-5 fusion products (heterokaryocytes) per 100 protoplasts. When incubated in culture medium, the heterokaryocytes regenerated cell walls and divided. The frequency of division depended on the viability of the protoplasts from carrot cell cultures, specifically, on the mitotic activity of the cells. Fusion of interphase carrot and barley nuclei was detected by differential staining. Synchronized mitosis was observed in heterokaryons containing barley and carrot nuclei.
NUCLEAR SUPPRESSORS OF THE [POKY] CYTOPLASMIC MUTANT INNEUROSPORA CRASSA. I. GENETICS AND RESPIRATORY PROPERTIES
Authors: Kohout J. , Bertrand H.
Published: November 2014

Six nuclear suppressors of the [poky] cytoplasmic mutant (sup-1, sup-3, sup-4, sup-5, sup-10, sup-14) have been obtained in Neurospora crassa. The sup genes suppress the slow growth phenotype of [poky], and alleviate, at least partially, the deficiency of cyanide-sensitive respiratory activity in the mycelium of this cytoplasmic mutant. The six suppressors are nonallelic, suppress the phenotypic effects of [stp-Bl] in addition to [poky], but have no effect on the phenotypic expression of the [mi-3] cytoplasmic mutant. On the basis of experimentally established molecular defects in [poky] and on the basis of hypothetical considerations, it is proposed that the sup mutations affect the structure and properties of mitochondrial ribosomal proteins.
INTERSPECIFIC INCOMPATIBILITY IN GOSSYPIUM. III. THE GENETICS OF TUMORIGENESIS IN HYBRIDS OF G. GOSSYPIOIDES
Authors: Phillips Lyle L.
Published: November 2014

Stem tumorigenesis in interspecific hybrids of G. gossypioides is governed by a three-allele genetic system — Go, Gx, and Gy. In this system GxGy is the only tumorigenetic genotype. Among the 30-odd diploid and tetraploid species of Gossypium, G. gossypioides is the only diploid to carry Gy and G. raimondii is the only diploid that carries Go. Three of the four tetraploid species, G. hirsutum, G. tomentosum, and G. caicoense, have the Go allele in one genome and the Gx allele in the other; tetraploid G. barbadense has the Go allele in both genomes. Hybrids between G. gossypioides and Gx diploids (GxGy) develop tumors early in ontogeny and die as seedlings. Hybrids between G. gossypioides and GoGx tetraploids (GoGxGy) do not develop tumors until the 10-14 leaf stage and can survive several years. Hybrids with the GoGoGxGy and GoGoGoGxGy tumor genotypes (synthesized with polyploid stocks) have few and no tumors, respectively.
A STUDY OF COMBINING ABILITY FOR SOME DEVELOPMENTAL TRAITS IN A DIALLEL SET OF CROSSES IN PEARL MILLET
Authors: Chaudhary H. R. , Jana S.
Published: November 2014

A diallel cross involving ten selected inbred parents in pearl millet Pennisetum typhoides (Burm.) Staph and Hubb. was analyzed for the inheritance of number of functioning leaves and leaf size. The study revealed that both additive and dominance genetic variances were important for leaf size whereas additive genetic variance was of major importance for number of functioning leaves. However, nonallelic interactions evidently had considerable impact in the inheritance of both characters. Heritability for number of functioning leaves was higher than that for leaf size. Although specific and general combining abilities were significant for both characters, gca effect appeared to be more important than sca effect for both characters. It was proposed that a breeding procedure which could make an efficient use of both additive and nonadditive genetic variances would be appropriate for the improvement of pearl millet.
IMPROVED RESOLUTION OF THE MEIOTIC CHROMOSOMES IN BOTH SEXES OFEUXOASPECIES AND THEIR HYBRIDS (LEPIDOPTERA: NOCTUIDAE)
Authors: Fontana P. G.
Published: November 2014

An air drying and Giemsa staining technique produces consistently good quality cytological preparations when applied to different species of Euxoa (Lepidoptera: Noctuidae) and, in particular, it allows an improved resolution of the meiotic chromosomes in both sexes. All species so far investigated have a basic haploid chromosome complement of n(♀) = 31(XX); n(♂) = (XY). A single chiasma per individual bivalent is clearly visible in the male sex. Some chiasmata are formed in interstitial positions, but, by metaphase I, they have all undergone complete terminalization while the bivalents orient axially on the first division spindle. Direct evidence for lack of chiasma formation in the 31 hormorphic bivalents in the female sex is reported for the first time for species of Noctuidae. Evidence in favor of an XY system in the female sex is discussed. Preliminary studies of the meiotic divisions in hybrid material reveal the presence of cryptic structural differences between certain taxa, and will help to elucidate taxonomic problems within this complex genus.
A NOTE ON HAYMAN'S DIALLEL ANALYSIS OF F2GENERATION
Authors: Dhillon B. S. , Malhi S. S.
Published: November 2014

Estimation of genetic parameters in Hayman's diallel analysis of the F2generation is discussed. Formulae to calculate standard errors of these parameters are given.
INHERITANCE OF PHOTOCHEMICAL AIR POLLUTION TOLERANCE IN PETUNIAS
Authors: Hanson George P. , Addis Daniel H. , Thorne Linda
Published: November 2014

Seven commercial inbred lines of pink flowered multiflora petunia (Petunia hybrida Vilm.) which differed widely in degrees of tolerance to photochemical oxidants were crossed in all possible combinations to yield a complete diallel cross. Sibling representatives of all 49 possible hybrids were then separately subjected to ozone (O3), peroxyacetyl nitrate (PAN), and ambient oxidants at Arcadia, California. The seedlings were scored for tolerance to each pollutant and the inheritance of tolerance to each pollutant was studied. At the ambient levels of photochemical oxidants encountered, PAN more severely injured the petunias than did the O3component. Hybrids tolerant to one oxidant were not necessarily tolerant to the other. The genes which contributed photochemical oxidant tolerance in petunia acted primarily in an additive manner with some indication of partial dominance for tolerance. Gene interaction was evident in the expression of petunia sensitivity to PAN.
GENETIC ANALYSIS OF NURSE DAMS SELECTED FOR SIX-WEEK BODY WEIGHT OR POSTWEANING GAIN IN MICE
Authors: Nagai J. , Bakker H. , Eisen E. J.
Published: November 2014

A modified crossfostering technique was developed to compare the performance of nurse dams in selected and control populations of mice. The H6and M16 populations were selected for increased 6-week body weight and 3- to 6-week postweaning gain, respectively, while the C2and ICR populations were the respective controls. Crossfostering was performed using H6, M16 and their reciprocal F1crosses as nurse dams in the selected crossfostering group and C2, ICR and their reciprocals in the control group. Measurements recorded for nurse dams included mean body weight of 8 young within a nursed litter at birth (MWB) and 12 days of age (MW12). The latter was used as a measure of postnatal maternal performance. Other traits recorded for nurse dams were number born (NB), body weight at parturition (DWP) and 12 days postpartum (DW12), and weight gain (DWG), feed intake (FED) and efficiency (EFF = DWG/FED) for the first 12 days of lactation. The correlated response in MW12 was negative (P <.01) for M16 and essentially zero for H6. Both lines exhibited positive (P <.01) correlated responses in DWP and DW12 and no change in EFF. Only the H6line increased significantly in DWG and FED as a result of selection. NB increased in M16 and H6, but was significant for the latter population only. Population differences in selection response [(M16-ICR)-(H6-C2)] were significant for FED only, primarily due to average direct genetic effects. Direct comparisons of M16 and H6indicated that M16 was larger in DWP and DW12 but smaller in DWG and EFF. Average direct genetic effects favored M16 for NB, DWP, and DW12, whereas average maternal genetic effects favored H6for NB, DWP, DW12 and FED. Percent direct heterosis in F1crosses of the selected populations was significant for MW12 (13.7%), FED (10.8%) and NB (11.4%). Direct heterosis in F1crosses of the controls was significant for MW12 (9.4%), NB(6.6%), DWP (3.5%), DW12 (3.3%) and FED (4.4%). The effects of MW12, DWG and metabolic body size (MBS) accounted for 47% of the variation in FED, pooled within populations. Of these variables, MW12 accounted for the highest proportion (32%) of variation in total feed intake.
CYTOLOGICAL DIPLOIDIZATION IN THE CULTIVATED OCTOPLOID STRAWBERRYFRAGARIA×ANANASSA
Authors: Byrne D. , Jelenkovic G.
Published: November 2014

Chromosome pairing during meiosis was studied in 9 cultivated genotypes and 32 seedlings produced by selfing several different genotypes of the octoploid strawberry Fragaria × ananassa Duch. (2n = 8x = 56). In all genotypes studied the chromosomes paired exclusively as bivalents indicating cytological diploidization. Meiotic studies of one of the S1plants, which was completely sterile, revealed that the chromosomes were paired at pachytene but desynapsed during diplotene, so that very little bivalent association was observed in late prophase of meiosis. The pairing in the F. × ananassa × F. nubicola pentaploid hybrids showed an average of 11.6 bivalents per PMC and frequent multivalent formation. There is thus an indication of residual homology between the ancestral genomes of the octoploid strawberry.
CYTOGENETICS OF PASPALUM CONSPERSUM AND ITS GENOMIC RELATIONSHIP WITH YELLOW-ANTHERED P. DILATATUM AND P. MALACOPHYLLUM
Authors: Burson Byron L. , Bennett Hugh W.
Published: November 2014

Paspalum conspersum Schrad. ex Schult. is a leafy, robust, warm season perennial bunchgrass native to South America. A cytogenetic investigation was conducted to determine the feasibility of using the grass in an interspecific hybridization program. Four introductions were studied and each had a chromosome number of 2n = 4x = 40. During meiosis, the chromosomes paired primarily as bivalents with an occasional quadrivalent and a limited number of univalents. A study of megasporogenesis and embryo sac development revealed that the plants were sexual. Eighty hybrids were obtained from yellow-anthered P. dilatatum Poir, 2n = 4x = 40, × P. conspersum. Thirty of these were examined cytologically. All had a chromosome number of 2n = 4x = 40. Mean meiotic pairing was 19.87 I, 9.94 II, 0.12 III, and 0.004 IV. Because of segmental homology between the P. conspersum genomes, it was difficult to determine the relationship between the two species. Thus, P. conspersum was crossed with autotetraploid P. malacophyllum Trin., 2n = 4x = 40, to determine the amount of autosyndetic pairing between the P. conspersum chromosomes. One hybrid was obtained and it had a chromosome number of 2n = 4x = 40. The mean pairing behavior was 15.74 I, 12.07 II, and 0.008 IV. Ten of the bivalents were interpreted as autosyndetic pairing of the P. malacophyllum chromosomes and the remaining 2.07 bivalents as autosyndetic pairing of the P. conspersum chromosomes. These findings also show no homology between P. conspersum and P. malacophyllum chromosomes and suggest the species are not closely related. Since there is limited autosyndetic pairing between members of the P. conspersum genomes, data from the P. dilatatum × P. conspersum hybrids indicate the two species have at least one common genome. Megasporogenesis was normal in both groups of hybrids. However, in the P. dilatatum × P. conspersum hybrids, the sexual tissue generally deteriorated, resulting in complete abortion of the female gametophyte. In the P. conspersum × P. malacophyllum hybrid, about 90% of the mature ovules had sexual embryo sacs. However, in the remaining ovules there was either deterioration of the sexual tissue or other abnormalities.
THE GENETIC CONTROL OF SUNFLOWER SEED ACID PHOSPHATASE
Authors: Torres Andrew M. , Diedenhofen Ulrike
Published: November 2014

Genetic studies indicate that the acid phosphatase isozymes in seeds of the annual sunflower (Helianthus annuus) are specified by a single gene, Acp, having at least four codominant alleles, S, B, I and F. The enzyme is presumably dimeric. The polypeptide subunits in heterozygotes form an intragenic heterodimer in addition to two homodimers. Acp is not linked to either of the genes coding for seed alcohol dehydrogenase, Adh-1 and Adh-2, and these are not linked to each other. Acp therefore provides a molecular marker for a third sunflower linkage group. The estimated molecular weight of the intact, functional enzyme is about 95,000 daltons.
EFFECTS OF OZONE ON MEIOTIC CHROMOSOMES OFVICIA FABA
Authors: Janakiraman Rajeshwari , Harney Patricia M.
Published: November 2014

All of the levels of ozone used in these experiments caused morphological damage to plants of Vicia faba L., but only the dose of 200 parts per hundred million for 4 h or 8 h caused chromosomal damage in the microsporocytes. Significant chromosomal damage appeared 24 h after fumigation in metaphase I and anaphase I - telophase I but no significant damage was found in anaphase II - telophase II. This observation suggests that chromosomes are more susceptible to ozone during early stages of meiosis than at later stages. Chromosomal damage was of two types: physiological, as suggested by chromosome stickiness and physical, as indicated by bridges, fragments, and micronuclei.
A CONTRIBUTION TO THE STUDY OF LINKAGE DISEQUILIBRIUM INDROSOPHILA MELANOGASTER
Authors: Alahiotis S. , Pelecanos M. , Zacharopoulou A.
Published: November 2014

Linkage disequilibrium was detected in 12 out of 30 cases involving gene alleles and inversions in three cage populations and in a natural population of Drosophila melanogaster from Greece. The cage populations possessed practically the same gene pool at their origin and were maintained simultaneously under the effects of the ecological factors "food medium" and "humidity". It is discussed that the correlation of the same direction found between the frequencies of nonallelic elements of Adh locus and In(2L)22D-34A or In(2R)52A-56F in such different populations as American, Japanese (Mukai et al., 1971, 1974; Langley et al., 1974) and Greek, as well as cage populations under different environmental conditions, could be attributed to the effect of epistatic selection. Moreover, it seems that the In(2L)22D-34A has a tendency to interact genetically with the α-Gpdh locus, particularly when the populations are maintained under crowding conditions. However, further data are needed to assess whether other cases of the observed nonrandom associations can be better explained as transient associations generated by random drift, or as the result of epistatic selection.
MEIOTIC ASSOCIATIONS IN BARLEY LINES WITH EIGHT PAIRS OF CHROMOSOMES AND THEIR HAPLOIDS
Authors: Finch R. A. , Kasha K. J.
Published: November 2014

Meiosis was studied in pollen mother cells and embryo sac mother cells of seven lines of eight-paired barley (Hordeum vulgare L.) in diploids (2n = 16) and their haploids (2n = 8). Translocation 5-7a, whose breakpoints are distal on chromosome 5 and in the satellite of chromosome 7, was found in all lines. The extra fragment chromosome (8) is a normal or translocation form of chromosome 5 deficient for terminal regions. In diploids, the extra chromosome behaves regularly at meiosis except for occasional univalent-formation and can form a symmetric ring bivalent, but it never forms chiasmata with other chromosomes. In haploids, however, it forms a low frequency of chiasmata with chromosome 5 but this frequency is reduced when the terminal region of chromosome 5 pairs homologously with the satellite region of 7. Based on the hypothesis used to explain chromosome pairing behavior, it should be possible to derive and identify additional eight-paired lines that would be useful for breeding.
MATERNALLY INFLUENCED EMBRYONIC LETHALITY: ALLELE SPECIFIC GENETIC RESCUE AT A FEMALE FERTILITY LOCUS INDROSOPHILA MELANOGASTER
Authors: Romans Patricia , Hodgetts R. B. , Nash D.
Published: November 2014

A new locus, mel(l)R1, with a maternal effect on embryonic development, has been mapped at about 0.5 on the X chromosome of Drosophila melanogaster and localized cytologically between bands 2D6 and 3A1. Genotypically mutant embryos die if produced by homozygous mutant females but survive if produced by heterozygous females. Two mutant alleles have been isolated. One of these is genetically rescuable: when homozygous mutant females are mated to mutant males, all the embryos die, but when these females are mated to normal males, female offspring are produced. The other allele is not rescuable. Genetic rescue is dominant at this locus since females heterozygous for the two mutant alleles produce female offspring in crosses to normal males.
WHOLE MOUNT ELECTRON MICROSCOPY OF THE NUCLEOLUS IN SALIVARY GLAND CELLS OF DROSOPHILA MELANOGASTER
Authors: Burkholder Gary D.
Published: November 2014

The nucleolus of Drosophila melanogaster salivary gland cells, examined by whole mount electron microscopy, consists of a fibrillar core region and a peripheral region containing both fibres and granules. These regions appear to correspond to the fibrillar and granular components, respectively, seen in thin sections. Most of the nucleoli were attached to the chromocenter region of the polytene chromosomes, containing the nucleolar organizer. Bundles of relatively straight chromatin fibres, 13 nm in diameter, extended from the chromocenter into the core region of the nucleolus, however it was not possible to trace the path of these chromatin fibres through the nucleolus since they were obscured within the mass of nucleolar fibres. The nucleolar fibres in both the core and peripheral regions were irregular and knobby, with a diameter of about 15 nm. In the core region, the fibres appeared to be of considerable length and were characteristically clustered together to form small interconnected masses. The fibres in the peripheral region were relatively short and some appeared to blend with amorphous, poorly-defined pools of material. Electron dense granules 15-20 nm in diameter were also associated with this amorphous substance. It is hypothesized that the formation and subsequent packaging of the 28s rRNA may be represented by a morphological transition of the peripheral fibres, via an amorphous pool-like intermediate stage, into the nucleolar granules. The results of this study indicate that whole mount electron microscopy may be a useful alternative to thin sectioning in high resolution studies of the nucleolus.
THE EFFECT OF WHEAT CYTOPLASM ON MEIOSIS OF HEXAPLOID TRITICALE
Authors: Roupakias D. G. , Kaltsikes P. J.
Published: November 2014

The interrelationships among source of cytoplasm, chromosome pairing and the duration of meiosis were studied in eight combinations of hexaploid triticale (× Triticosecale Wittmack) grown at 20 °C under continuous illumination. The number of paired chromosome arms and univalents per pollen mother cell at MI ranged from 32.32 and 4.89 to 37.26 and 1.37, respectively. Meiosis lasted from 44.14 to 49.35 hours. A significant positive correlation (r = 0.92) was found between total duration of meiosis and the combined duration of zygotene and pachytene, the stages during which chromosome pairing is thought to occur. The origin of the cytoplasm (from tetraploid or hexaploid wheat) had no significant effect of chromosome pairing or meiotic duration. No relationship was found between total duration of meiosis, or that of zygotene and pachytene, and chromosome pairing. It was concluded that lack of sufficient time for homologues to pair cannot account for the presence of rye chromosomes as univalents in triticaie.
INTROGRESSION BETWEEN THE CULTIVATED HEXAPLOID OAT A. SATIVA AND THE TETRAPLOID WILD A. MAGNA AND A. MURPHYI
Authors: Ladizinsky G. , Fainstein R.
Published: November 2014

Introgression between the hexaploid (2n = 42) oat A. sativa and the newly discovered tetraploid (2n = 28) species A. magna and A. murphyi was studied by the rate of stabilization of chromosome number, restoration of fertility of pentaploid hybrid derivatives and the ultimate gene transfer between the tetraploid and the hexaploid levels. The complete self-sterility of the pentaploid F1 hybrids was overcome by massive back-pollination to the parental species. Great variation in chromosome number (12-48) was found among the viable F1 female gametes. Meiotically stable and reasonably fertile derivatives were selected only at the F2 of the BC and in a relatively small proportion. Gene transfer between the tetraploid and the hexaploid species was demonstrated by introducing the allele for nonshattering seed from the cultivated oat A. sativa to both A. magna and A. murphyi, and lemma hairiness from the tetraploids to the hexaploid level. The possible exploitation of introgression between the polyploid oats for breeding purposes has been pointed out and the potential of A. magna and A. murphyi as cultivated oats has been briefly discussed.
MEIOTIC IRREGULARITIES CAUSED BY INTERACTING STERILITY GENES IN CULTIVATED SAFFLOWER (CARTHAMUS TINCTORIUS)
Authors: Carapetian Jirair , Rupert Earlene A.
Published: November 2014

Microsporogenesis was studied in the male-female sterile F2 segregants of a safflower cross involving 'US-10' and '57-147' cuitivars and was compared with normal meiosis in the F1 hybrids. In the microspores of the sterile plants contraction of chromosomes during prophase was irregular and patchy and they did not stain well with acetocarmine. At MI, most of the 24 chromosomes tended to stick to each other at random resulting in the formation of several chromosome bridges during AI. Multipolar meiotic divisions were observed. The second division was rarely seen. Apparently, meiosis ends with a multipolar AI separation and with the formation of 3- to 9-celled "quartets" which later develop nonfunctional pollen grains. The onset of meiosis in sterile plants was delayed and microsporogenesis subsequently progressed at a much slower rate than in fertile F1 hybrids. Three interacting nuclear genes appear to cause male-female sterility and affect microsporogenesis by interfering with some component essential for normal meiosis.
DYNAMICS OF UNSTABLE SPOROPHYTIC SELF-INCOMPATIBILITY SYSTEMS
Authors: Sampson D. R.
Published: November 2014

Sporophytic self-incompatibility systems were studied by using deterministic computer simulation. Frequencies of individual S alleles, or combinations of S alleles, were set at 0.001 of their equilibrium frequency and observations were made on the speed with which equilibrium was restored. Ten cases were studied, each of which had three variants regarding the site of dominance, i.e., in the pollen, in the stigma, and in both sexes. Dominant alleles regained equilibrium much faster than did recessive alleles, but both types were slower than the 11th case in which all alleles acted individually. Alleles that acted independently of the dominance series were almost as slow to regain equilibrium as were the recessive alleles. Models with dominance confined to the pollen were unstable in that all of the recessive alleles except one could become extinct. The results are discussed in terms of known sporophytic systems and the evolutionary strategies that would enable a species to acquire several pollen recessive S alleles.
IN VITRO REGENERATION OF SHOOTS ON STEM EXPLANTS OF HAPLOID AND DIPLOID FLAX (LINUM USITATISSIMUM)
Authors: Murray Beatrice E. , Handyside R. J. , Keller W. A.
Published: November 2014

Shoots were regenerated from stem explants of haploid (2n = x = 15) and diploid (2n = 2x = 30) flax (Linum usitatissimum L. cv. Rocket 4) on a modified Murashige and Skoog (1962) medium supplemented with benzyladenine and napthaleneacetic acid. Segments of 15 mm lengths, cultured from donor plants at early flowering, regenerated 6.1 (mean) shoots per mm which were epidermal in origin and retained the chromosome number of the donor. The rate and frequency of shoot regeneration was greater at 30 °C as compared to 25 °C. Callus originated from the cut ends of explants and was more vigorous at the lower temperature. Shoots of callus origin were infrequent and had the doubled chromosome complement (2n = 2x = 30 and 2n = 4x = 60).
MEIOSIS IN 8-CHROMOSOME BARLEY HAPLOIDS
Authors: Fedak George
Published: November 2014

Meiosis was studied in four 8-chromosome haploid plants produced from Wiebe's barley (2n = 14 + 2 centric fragments) (Hordeum vulgare L.) in which the extra chromosome had lost its telomeres and was one-third the length of a normal chromosome. Although secondary associations occurred, pairing between the normal and fragmented chromosome was rare despite the presence of homologous segments between them, indicating that the deletion of the telomeres restricted chromosome synapsis. A high bivalent frequency was attributed to a translocation between a long and short chromosome of the normal complement that persisted through the haploidization process.
A CYTOPHOTOMETRIC INVESTIGATION OF THE RELATIONSHIP OF DNA AND RNA SYNTHESIS TO ASCUS DEVELOPMENT INSORDARIA FIMICOLA
Authors: Bell W. R. , Therrien C. D.
Published: November 2014

Results from quantitative cytochemical analyses of Feulgen-DNA and azure B-RNA content of different stages of ascus development in the pyrenomycete Sordaria fimicola Ces. and DeNot. may be summarized as follows: (a) DNA replication in nuclei of the prefusion ascus (penultimate cell) precedes karyogamy, hence the prefusion nuclei are 2C (replicated haploid), and the fusion nucleus 4C (replicated diploid) in DNA content. These data show that premeiotic S phase and genetic recombination cannot be coincident since DNA replication is complete prior to nuclear fusion in the crozier penultimate cell. (b) DNA replication in the basal and terminal cell nuclei of the crazier does not occur until DNA replication is complete in the subterminal (penultimate) cell. Therefore, DNA replication occurs first in the cell which forms the primary ascus. (c) During ascus enlargement, which occurs during pachytene and diplotene, the total ascus RNA content increases from 18.9 to 195.4 arbitrary units (a.u.), while at the same time nucleolar RNA increases from 0.5 to 1.7 a.u. The concurrent increase in nucleolar and ascus RNA suggests that a rather substantial proportion of the increase in total ascus RNA may be due to the synthesis of ribosomal RNA. (d) In asci which contain binucleate ascospores the total RNA content has increased to 281.5 units. This increase may represent a storage of RNA to be utilized for protein synthesis during the subsequent germination of the ascospore. (e) Ascospores in mature asci of eight day old cultures were always multinucleate. The multinucleate condition is presumably established in preparation for ascospore germination and the initial growth of the germ tube.
THE EFFECT OF MITOMYCIN ON THE FERTILITY AND THE INDUCTION OF MEIOTIC CHROMOSOME REARRANGEMENTS IN MICE AND THEIR FIRST GENERATION PROGENY
Authors: Savković N. , Green S. , Pečevski J. , Marić N.
Published: November 2014

The dose dependent effects of chronic application of Mitomycin C(MC) on the induction of chromosomal translocations in treated animals and F1 males and on their fertility have been examined. The C3H strain mice used in the present experiments were treated with MC during eight successive weeks in doses of 0.05 mg/kg and 0.1 mg/kg of body weight. 75 males were treated (25 males per dose and 25 males as controls). Immediately after the chronic treatment they were mated with normal females and were tested for their reproductive performance. The fertility of males was estimated from the number of pregnant females after one week of being together. After that all males were sacrificed and prepared for cytological analysis. No chromosomal translocations were found in diakinesis-metaphase I of meiosis. Data from the study of fertility showed that all treated males were fertile, but all females were not pregnant. The testes of all sterile, semisterile and fertile F1 males showed that F1 males could not be identified as heterozygous translocation carriers.
SERUM CHOLESTEROL, ACTIVITY, FEED INTAKE, AND BODY WEIGHT IN LINES OF MICE SELECTED FOR GROWTH
Authors: Dunnington E. A. , White J. M. , Vinson W. E.
Published: November 2014

Feed intake, growth and serum cholesterol (SC) were recorded on 102 male mice, and voluntary physical activity and SC were recorded on 113 male mice from lines selected for maximum 21- to 42-day weight gain (H), for minimum 21- to 42-day weight gain (L), and from a random-bred unselected control line (C). Voluntary physical activity in a revolving wheel was recorded for a 22-h period every sixth day from 3 to 10 weeks of age. Growth and feed intake on two different diets (diet 1 containing 4.5% fat and 23.4% protein; diet 2 containing 11% fat and 17% protein) were measured three times per week and rate of weight gain was calculated on a weekly basis. Blood samples were obtained by sinus orbital bleeding at 5 and 10 weeks of age after six hours fasting and analyzed for SC by gas chromatography. A least squares analysis of variance of the SC data using a model including lines, diets, ages and all possible interactions indicated highly significant differences in the main effects and in most of the interactions. SC and growth were higher and feed intake was lower in mice on diet 2. SC values (mg/100 ml) were 143.3, 124.1 and 132.2 at 10 weeks of age for H, C and L line animals fed diet 1 and 220.3, 178.1 and 180.4 for animals fed diet 2. An analysis of variance in the activity data resulted in highly significant differences in the main effects (line and age) but revealed no significance in the interaction. Activity scores (revolutions) for the H, C and L lines were 79234, 107987 and 124409, respectively for eight 22-h periods. Activity reached maximum levels at 56 days of age, then declined slightly. Within line phenotypic correlations between SC and activity and between SC and feed intake were significant throughout ages of testing only in the high line.
GENOTYPIC INTERACTION FOR CHIASMA FORMATION AT LOW TEMPERATURE IN THE HYBRID BETWEENTRITICUM AESTIVUM'CHINESE SPRING' ANDAEGILOPS SPELTOIDESDEFICIENT FOR CHROMOSOME 5D
Authors: Attia T. , Lelley T. , Röbbelen G.
Published: November 2014

In F1plants from crosses between Triticum aestivum var. 'Chinese Spring' monosomic 5D and Aegilops speltoides Tausch. var. aucheri (Boiss) it was found that at a temperature of 12 °C the presence of chromosome 5D is necessary to maintain the level of homoeologous pairing and chiasma formation observed under greenhouse conditions. Some genotypes of Ae. speltoides, however, were more efficient than others in compensating for the absence of chromosome 5D. The differences in compensating ability indicate the existence of several alleles in Ae. speltoides that counteract the low-temperature pairing system on chromosome 5D. An analogous system of alleles previously reported in Ae. speltoides that suppresses the chromosome 5B diploidising system of wheat was substantiated by the present study. The results indicate, however, that the two systems are independent.
ISOLATION AND CHARACTERIZATION OF TEMPERATURE SENSITIVE SPORULATIONLESS MUTANTS OF THE BASIDIOMYCETESCHIZOPHYLLUM COMMUNE
Authors: Bromberg Susan K. , Schwalb Marvin N.
Published: November 2014

A technique is described for the isolation of temperature sensitive sporulationless mutants from the basidiomycete Schizophyllum commune Fries. Three mutants were isolated and characterized. Mutant spo is stopped during meiosis and mutant stg produces abnormal sterigmata. Mutant ts shows no development at any stage at the retrictive temperature (30 °C).
MICROTUBULE DISTRIBUTION IN THE ANAPHASE SPINDLE OF PRIMARY SPERMATOCYTES OF A CRANE FLY (NEPHROTOMA SUTURALIS)
Authors: Forer Arthur , Brinkley B. R.
Published: November 2014

Microtubules are described in crane fly spermatocytes (Nephrotoma suturalis Loew). The numbers of microtubules as determined from serial transverse sections of the spindles were compared in different regions of anaphase spindles: the interzonal regions had 60-80% of the number of microtubules between the chromosomes and the poles. The microtubule densities per micrometer-square cross-sectional area of the spindle were determined: the density of interzonal microtubules (i.e., those between the separating chromosomes in anaphase) was two to three times less than that of the kinetochore-associated microtubules, and the density of interzonal microtubules was about that of microtubules between the chromosomes and the poles once the kinetochore-associated microtubules were subtracted from the total. Microfilaments [Formula: see text] were also seen in the spindles. Sex-chromosomes in crane fly spermatocytes are amphitelically oriented, and tubular "bridging" material was seen extending between the two kinetochores of each sex-chromosome. The tubular "bridging" material is presumably related to the amphitely.
THE EFFECT OF TELOMERIC HETEROCHROMATIN ON CHROMOSOME PAIRING OF HEXAPLOID TRITICALE
Authors: Roupakias D. G. , Kaltsikes P. J.
Published: November 2014

Plants carrying (++) or lacking (−−) most of the telomeric heterochromatic band on the short arm of chromosome 6R(6RS) were isolated from a single plant progeny of Rosner triticale (× Triticosecale Wittmack) heterozygous for this band. Chromosome pairing at first meiotic metaphase was significantly higher in −− than in ++ or +− plants. The changes in chromosome pairing were likely due to the 6RS telomeric heterochromatin which affected the pairing not only of the arm carrying it but of other chromosomes as well.