Sterile Forms Research Articles

On saving mythic criticism—A Reply to Rowland

This essay critically examines the definition of myth put forth by Rowland in this issue, and considers implications of his approach for critical method. It is argued that Rowland's reformulation of myth is a narrow and conservative one that imposes its own mythic worldview of functional empiricism on the conceptualization of myth, and encourages a sterile form of criticism that reduces the interpreter to a passive recorder of events.

Growth improvement in carp, Cyprinus carpio (Linnaeus), sterilized with 17 α-methyltestosterone

The effect of dietary administration of 17α-methyltestosterone (17α-MT) (300 and 400 ppm) over a period of 30 days, starting with 1-day-old hatchlings, on the sex and growth of the carp, Cyprinus carpio (Linn.), was investigated. After the treatment period, the fry were reared on a hormone-free diet for 365 days. Administration of 17α-MT at 300 ppm resulted in a population of 8% males, 6% females and 86% sterile individuals. At 400 ppm, 17α-MT induced a female-free population, consisting of 98.25% sterile forms and 1.75% males. The control group consisted of 51% males and 49% females. At the end of the 12-month post-treatment rearing period, the increases in the mean final weights of the fish in the 300 and 400 ppm treated groups were 40.64% and 46.87% respectively when compared with the control. Loss of weight due to evisceration was only 5.59–7.42% in the hormone-treated groups, while it was 14.95% in the control fish, suggesting the availability of more edible meat per unit weight from hormone-treated fish. The results suggest that sterile fish produced by administration of 17α-MT would grow better and yield more meat per unit weight than untreated fish. They also suggest that production from composite fish culture (polyculture) can be further enhanced by using hormone-induced sterile fish.

Incidence of hysterectomy and tubal ligation in public hospitals in south Australia, 1980-82.

SummaryThis paper presents information on the incidence of hysterectomy and tubal ligation in South Australia in the period 1980–82, and on the age, marital status and ethnicity of women undergoing these procedures in public hospitals during the period. A typical woman undergoing one of these procedures was married or previously married and in her mid-40s for hysterectomy or mid-30s for tubal ligation. South Australian women had a lifetime chance of one in six of undergoing hysterectomy and of one in five of undergoing tubal ligation. The findings are consonant with the suggestion that increasing numbers of women are choosing forms of sterilization as means of contraception.

Breeding sunflower cultivars for the northern latitudes

Development of short season sunflower hybrids has been the main objective of the Canadian sunflower breeding program. A gene pool created with 50 lines extracted from USSR open-pollinated varieties provided a good source of early inbred lines. The gene pool produced the lines CM447, CM469 and CM497 which were the basis for the superior early parental lines. Another early line, CM594, was extracted from Armavirec. CM447 and CM594 were converted to the cytoplasmic male sterile (cms) form, while CM469 and CM497 were used in the development of fertility-restorer lines. Hybrids from these lines and in combination with HA3O1, HA232, and NS39 resulted in up to 15 days earlier maturity than the standard hybrids, with good oil content, disease resistance and lodging resistance. An early dwarf hybrid. Sunwheat, developed by SeedTec shows good performance in late seeded tests, but it requires higher plant population and a narrow row spacing.

Asymmetric hybridization in Nicotiana by fusion of irradiated protoplasts

Mesophyll protoplasts of a kanamycin-resistant, nopaline-positive Nicotiana plumbaginifolia seed line were inactivated by γ-irradiation and electrically fused with unirradiated mesophyll protoplasts of N. tabacum. Hybrids were selected on kanamycin and regenerated. Genetic material from N. plumbaginifolia was detected in these plants by the following criteria: (1) morphology, (2) esterase isozyme profiles, and (3) the presence of nopaline in leaf extracts. All of the plants regenerated were morphologically more similar to N. tabacum than to N. plumbaginifolia, and many were indistinguishable from N. tabacum. It was found that 37 plants displayed one or two esterases characteristic of N. plumbaginifolia in addition to a full set of esterases from N. tabacum. Based on their esterases, we have classified these plants as somatic hybrids. However, irradiation has clearly reduced the amount of N. plumbaginifolia genetic material that they retain; 24 plants were found that had only N. tabacum esterases but that produced nopaline and were kanamycin resistant. Genomic DNA from several of these plants was probed by Southern blotting for the presence of the authentic neomycin phosphotransferase gene (kanamycin-resistance gene) - all were found to contain the gene. These plants were classified as asymmetric hybrids. Finally, 25 plants were regenerated that were kanamycin sensitive, negative for nopaline, and contained only N. tabacum esterases. All of the regenerated plants, including this final category, were male sterile. As transferring the N. plumbaginifolia cytoplasm to an N. tabacum nuclear background results in an alloplasmic form of male sterility, all of the plants regenerated in this study appear to be cybrids irrespective of their nuclear constitution. Chromosome analysis of the asymmetric hybrids showed that most of them contained one more chromosome than is normal for N. tabacum. The somatic hybrids examined all had several additional chromosomes. Although male sterile, the asymmetric hybrids were female fertile to varying degrees and were successfully backcrossed with N. tabacum. Analysis of the resultant F1 progeny indicated that the kanamycin-resistance gene from N. plumbaginifolia is partially unstable during meiosis, as would be expected for factors inherited on an unpaired chromosome.

Impaired spermatogenesis in the finch hybrid L. castaneothorax by L. punctulata: transmission electron microscopy and genetic analysis.

As part of a project to determine whether there is any correlation between the form of hybrid sterility and the genetic relatedness of the parental species, we studied a male intrageneric hybrid between two finch species (Lonchura castaneothorax X L. punctulata), and compared the ultrastructural basis of hybrid sterility in this species with that reported by Swan [1985] for an intergeneric bird hybrid. In the latter study the sterility appeared to have an autoimmune basis, due to lack of Sertoli-Sertoli tight junctions. In the hybrid examined in the present study, lanthanum tracing showed that the junctions were tight. There was no testicular immune reaction; the parental species were almost identical in chromosomal constitution, having only a small inversion difference on chromosome 5, and only two structural protein differences could be detected through examination of the variation at 38 protein loci. Nevertheless, the hybrid appeared sterile and had the following ultrastructural testicular features. Intercellular bridges where present were usually abnormal in structure; centrioles in a centriole pair were arranged in parallel. Many spermatocytes and spermatids degenerated and were phagocytosed by Sertoli cells. Some spermatids progressed to mature testicular spermatozoa in sperm bundles, but commonly had multiple (2-4) axonemes or disrupted doublets and accessory fibers. The multiple axonemes present in most spermatids inserted separately into the base of the nucleus and the multiple centrioles were capable of organizing separate neck structures. We conclude that these cytological abnormalities were caused by genic effects and discuss why they appeared to be restricted to the germ line.

A relativistic mass tensor with geometric interpretation

We derive a relativistic mass tensor (dyadic or matrix) whose origin and properties have a direct geometric interpretation in terms of projection operators related to the particle’s world line and local inertial frame in Minkowski space, yet whose eigenvalues are simply the longitudinal (ml) and the transverse (mt) mass. Writing the noncovariant equations of motion (EOM) for a point particle in terms of this mass tensor bridges the gap between the compact but sterile form of the Lorentz covariant EOM and the usual (‘‘unwieldy’’) noncovariant EOM in which ml and mt appear. General expressions for 3- and 4-space mass (inverse mass) tensors are presented in terms of the system Lagrangian (Hamiltonian).

Microfungi of Mac.Robertson and Enderby Lands, Antarctica

Filamentous fungi were isolated from soils and plant and animal material using Warcup's soil plate method. Collections were made at eight localities in Mac. Robertson Land and five in Enderby Land, between December 1979 and October 1980. The major taxa isolated were Penicillium spp., especially P. brevi-compactum and P. cyclopium, and Cladosporium herbarum. Sterile forms comprised 47% and 60% of isolates from Mac. Robertson and Enderby Lands, respectively. Sporothrix ?ramosissima was isolated from Mac.Robertson Land soil. This represents the first record of this genus from Antarctica.

Soil microfungi in an area polluted by heavy metals

The microfungal species composition was studied in coniferous forest soils surrounding a brass mill at Gusum in southeast Sweden. Both the Cu and Zn concentrations were ca. 20 000 μg/g dry soil close to the mill. Pb concentration was ca. 1000 μg/g dry soil and the pH about 2 units above the normal of 3.5–4. The microfungal species composition (determined by the dilution plate technique) was strongly affected by the heavy-metal contamination. Close to the mill there was a decrease in isolation frequency of fungi common in coniferous forest soils, e.g., Penicillium spinulosum, P. montanense, P. brevicompactum, Oidiodendron cf. tenuissimum, O. cf. echinulatum, and O. maius. Other less common or rare fungi increased, e.g., Paecilomyces farinosus, Geomyces pannorum, Chalara constricta, C. longipes, and sterile forms. Fungi of the genus Mortierella seemed affected little by the heavy-metal contamination. Multivariate statistical analyses showed that the heavy-metal pollution was the dominating influence along the metal gradient and that soil moisture and loss on ignition accounted for little of the variation in the fungal data.

Microfungi and Microbial Activity Along a Heavy Metal Gradient

Soil fungal biomass, microfungal species composition, and soil respiration rate of conifer mor soil were studied along a steep copper and zinc gradient (up to 20,000 mug of Cu and 20,000 mug of Zn g dry soil) around a brass mill near the town of Gusum in South Sweden. Fungal biomass and soil respiration rate decreased by about 75% along the metal gradient. Above 1,000 mug of Cu g, the decrease was clearly evident; below 1,000 mug of Cu g, no obvious effects were observed, but there was a tendency for a decrease in total mycelial length. No decrease in CFU was found along the gradient, but fungal species composition was drastically changed. The frequency of the genera Penicillium and Oidiodendron decreased from about 30 and 20%, respectively, at the control sites to only a few percent close to the mill. Mortierella was most frequently isolated in moderately polluted sites, but at the highest pollution levels, a decrease in isolation frequency was evident. Some fungal taxa increased in abundance towards the mill, e.g., Geomyces (from 1 to 10%), Paecilomyces (0 to 10%), and sterile forms (from 10 to 20%). Analyses with a multivariate statistical method (partial least squares) showed that organic matter content and soil moisture had little influence on the fungal community compared with the heavy metal pollution.

Hormonal manipulation of sex in the common carp, Cyprinus carpio var. communis (Linnaeus)

Attempts were made to manipulate the sex of the common carp, Cyprinus carpio, by dietary administration of 17 α-methyl-testosterone (17 α-MT) (220 ppm) and 17 β-estradiol (17 β-E 2) (200 ppm) for 131 days starting with one-day-old hatchlings. Administration of 17 α-MT and 17 β-E 2, in general, retarded gonadal development and altered the sex ratio significantly. The 17 α-MT treated group had 46% male and 54% sterile forms while the 17 β-E 2 treated group had 15% male, 42% female and 43% sterile forms. The sex ratio of control fish was unaltered and had a more or less normal sex composition of almost 50% males and 50% females.

A new form of genetic female sterility in Capsicum annuum L.

During evaluation of genotypes of pepper ( Capsicum annuum L.), a female-sterile mutant was observed in one line. The mutant also exhibited flat stem and rosette branching-habit. The stamens were functional and pollen fertility was normal. Style and stigma were petaloid and non-functional. A single recessive gene caused the sterility and the other aberrant characteristics. The possible use of this mutant in a hybrid seed production programme in pepper is indicated.

Method for testing aseptic technique of intravenous admixture personnel

A method of checking the aseptic technique of personnel that prepare i.v. admixtures is described. The following sterile dosage forms of trypticase soy broth (TSB) were prepared: (1) single-strength ampuls 5 ml, (2) six-times (6X) concentrated broth ampuls 10 ml, (3) lyophilized broth sufficient to make 5 ml single-strength broth in 10-ml vials, and lyophilized broth sufficient to make 10.6 ml 6X concentrated broth in 20-ml vials. Admixture personnel were told these were investigational products, and they were given simulated orders to prepare syringes and 50-ml piggyback admixtures of the products. The specimens containing the broth were intercepted by an investigator, incubated for seven days at 37 degree C, and observed for turbidity on days 2 and 7. To verify that the broth supported the growth of bacteria, two common contaminants were inoculated into the broth in the syringes and admixtures to serve as positive controls. At least 100 samples from each of four procedures were processed during the three-month study period. A total of 405 samples prepared by 13 individuals were tested. None of the samples became turbid; hence, the bacterial contamination rate was 0%. Among the positive controls, 98% inoculated with one species and 100% inoculated with the other became turbid. This method is now used for monitoring the aseptic technique of new admixture personnel. This unique method of checking the aseptic technique of personnel is accurate and cost effective, and it avoids the risk of adventitious contamination.

Breeding systems and hybridization inPetrorhagia sect.Kohlrauschia (Caryophyllaceae)

In the diploid speciesP. prolifera, the evolution of autogamy has resulted in the presence of distinct selfing and outcrossing races. The change in breeding system toward autogamy is associated with a reduction in the size of floral features and a lower pollen production. The outbreeding populations have only been found in Greece, while the selfing populations have colonized much of Europe. The two races appear to be reproductively isolated from one another. —Petrorhagia sect.Kohlrauschia contains four species.P. glumacea is outbreeding and shows unilateral incompatibility with the small-flowered race ofP. prolifera and interfertility with the large-flowered race; althoughP. glumacea is sympatric with the large-flowered race, they do not appear to hybridize in the wild. Amongst the allopatric species, internal breeding barriers are also found. These may take the form of hybrid sterility or seed incompatibility.P. velutina is autogamous and reproductively isolated from all the other species of the section regardless of whether they are sympatric or allopatric. It is suggested that the evolution of autogamy has been an important factor in the spread ofP. velutina, the tetraploidP. nanteuilii, and the small-flowered race ofP. prolifera in Europe.

X-Chromosome involvement in male hybrid sterility from Glossina morsitans sub-species crosses

Crosses between sub-species of the tsetse fly Glossina morsitans yield males which can mate but are unable to inseminate. To test the hypothesis of X-chromosome involvement in this form of male sterility, G. m. morsitans carrying the X-chromosome marker ocra were mated to wild type G. m. centralis, and the F1 females backcrossed to each parental population. The ocra gene was used to distinguish those male progeny which had inherited their X-chromosomes from each sub-species and these categories of male from each backcross differed significantly in the proportion which could inseminate. It is concluded that inability to inseminate is caused by an interaction of the X-chromosome from one sub-species with the Y-chromosome and/or autosomal factors from the other. The results are discussed in relation to similar observations from crosses within two Anopheles species complexes and to the genetic control of tsetse flies.

Hybrid dysgenesis in Drosophila: correlation between dysgenic traits.

Crosses between laboratory stocks and extractions from wild populations have recently been shown to produce non-reciprocal genetic aberrations commonly termed hybrid dysgenesis, which appear to arise from a nuclear cytoplasmic interaction. Female sterility is one aspect which has been investigated and both poor egg production (GD sterility) and low hatchability (SF sterility) have been shown to contribute. It has previously been suggested that these characters may have an independent action and causation. The results presented in this paper however, show a high degree of correlation in the response of SF and GD sterility to various developmental temperature regimes, with both forms of sterility showing an increase as the developmental temperature rises. For each character, the whole of the life cycle appears to be affected by changes in the developmental temperature although two stages were identified as being particularly sensitive. The results therefore suggest that these two characters have a common cause and the relationship between these and other dysgenic traits is discussed.

Rhizosphere and root surface fungi of some heath plants and the role of Dark Sterile forms

Many different species of fungi have been isolated from the root region of heath plants. In the absence of rapidly growing species,Dark Sterile forms predominated in culture plates. It is suggested that these have an important ecological role in the soil-root interface. AsDS forms do not appear in culture plates easily any floristic list of fungi from the root surface not mentioningDS forms must be accepted with caution. Attention is drawn to the fact that these are truly root-inhabiting fungi possessing some parasitic or mycorrhizal propensities.

Nuclear and cytoplasmic genes controlling synthesis of variant mitochondrial polypeptides in male-sterile maize

The polypeptides synthesized in vitro by mitochondria isolated from etiolated maize shoots of a number of different nuclear and cytoplasmic genotypes have been compared by using polyacrylamide gel electrophoresis. We have previously shown that mitochondria from maize plants carrying the T or C forms of cytoplasmically inherited male sterility (cms-T and cms-C mitochondria) can be distinguished from each other and from the mitochondria of normal (N) plants by the synthesis of a single additional or variant polypeptide species. Using lines that carry the T cytoplasm, and that differ principally in the presence or absence of nuclear "restorer" alleles that suppress the male-sterile phenotype, we find that these nuclear genes specifically suppress synthesis of the 13,000 M(r) variant polypeptide. A 21,000 M(r) polypeptide that is synthesized by N mitochondria is not detectable among the translation products of cms-T mitochondria from either restored or nonrestored lines. Results obtained with a number of lines possessing dominant restorer alleles from different sources indicate that it is the restorer gene at the Rf(1) locus that is primarily responsible for regulating synthesis of the 13,000 M(r) polypeptide. Mitochondria from lines with the S form of cytoplasmic male sterility (cms-S) were found to synthesize a group of minor polypeptides, ranging in molecular weight from 42,000 to 88,000, which were not detected in N, cms-T, or cms-C mitochondria. In the case of the S and C forms of male sterility no differences were found between the translation products of mitochondria from restored and nonrestored lines.

Cytoplasmic Male‐Sterility in Flax: Restorer Gene Frequency and Degree of Corolla Opening1

A cytoplasmic male‐sterile flax (Linum usitatissimum L.) line was crossed with 1,455 entries from the USDA World Flax Collection. We determined the frequency of restorer genes in the collection and the possibility of using this type of sterility to develop a random mating breeding population to mix germplasm. Because 1,155 of the lines (79%) are sterility maintainers and because some natural field crossing occurs in flax, this sterility system should allow random mating flax populations to be developed for the first time. A second objective was to identify sources of genes that condition the production of open‐corolla, male‐sterile flowers in plants containing the sterile cytoplasm. This factor has prevented the use of this male‐sterility system to produce commercial flax hybrids. Thirty accessions were identified as possible sources of genes for this trait. It appears that breeding systems can be used to develop male‐sterile lines that produce normal open flowers accessible to insect pollination. Plant age affected degree of corolla opening and male‐fertility of the F1 plants. Average corolla opening decreased from 13.97 to 8.8 mm in I0 weeks for plants expressing this trait, while the number of F1 plants producing F2 seed increased from 155 to 302. Stability of both traits varied from line to line and should be of concern to breeders who use this form of sterility in flax improvement.

Observations onFosliella farinosa(Lamour.) Howe (Rhodophyta, Corallinaceae) in the British Isles

A description of Fosliella farinosa is given based on material collected in the British Isles between May 1975 and April 1977. Using field material and crusts cultured from uninucleate bispores the development and seasonal variation of the vegetative thallus and the trichocytes which it bears are discussed. The seasonal occurrence of the tetrasporangial, gametangial and bisporangial conceptacles is recorded. The previously little known bisporangial conceptacles are described in greater detail as is a sterile conceptacle form which develops in winter. Culture studies which have established the bisporangial life-history are reported. An account is given of the ecology of this species and finally the conflicting views of the delimitation of the genera Fosliella and Heteroderma are discussed.