Komparative Aussagemuster in Bezug zu komplementären und enkaptischen Modellen der Morphologie

The unity of organisms can be viewed in terms of the concepts of enkapsis and complementarity. A model (or a type) represents those properties (of elements, structure, and system) which renders cases - the organisms under consideration — comparable. Comparability is established by operations (or metamorphoses) which relate a case to a model. Therefore, the model and the operations must be enumerated together, if a certain morphology is to be established and applied. Two models, which in some way are related, are conjunct, otherwise they are disjunct. If one model is deducible from the other, they are enkaptic conjunct. If the models are essentially different, that is to say that they cannot be transduced into each other, although they condition each other, they are complementary conjunct: although not comparable themselves, only both together describe a case (or a set of cases) completely. Now, the comparability of a case with two models is considered. The two basic patterns of general comparability are homology and analogy. If the two models are complementary conjunct, nine patterns of special comparability can be distinguished. Each is named in accordance with the general meaning of homology and analogy and, as far as possible, with conventional scientific usage. With minor modifications the terminology also applies to more complicated patterns of comparability including distinct or different conjunct models.     

Immunofluorescence localization of the epidermolytic toxin target in mouse epidermal cells and tissue

Summary An epidermolytic toxin target was observed in keratohyalin granules of sectioned epidermis by a direct fluorescence procedure using FTC-toxin, but not by an indirect procedure using sequential reaction with toxin, anti-toxin and FTC-secondary antibody. The investigation of the two procedures was extended to keratinocytes. A dispase digestion procedure yielded three fractions which corresponded to basal, spinous and granular cells according to biochemical and morphological criteria. It was shown that the direct and indirect procedures both detected the toxin target in the keratohyalin granules of granular cells, but that the indirect procedure was very insensitive. In control experiments, the profilaggrin of keratohyalin granules was detected readily in cells by a direct procedure using FTC-antiprofilaggrin but only weakly by an indirect double antibody procedure. Insensitivity to indirect procedures thus appears to be a particular property of the keratohyalin granule site. It was shown that the toxin target was readily accessible in permeable (trypsin-isolated) granular cells but inaccessible in impermeable (dispase-isolated) cells.     

On morphological variation in Keratella cochlearis populations from Holstein lakes (Northern Germany)

Keratella cochlearis occurs in many Holstein lakes (northern Germany) as three well defined and separated forms: cochlearis, hispida, and tecta, each showing very little variation between the lakes. The present data show that the tecta form did not originate from a Lauterborn cycle.     

Effect of giving insulin and adrenalin alternately on changes in the level of blood glucose in chickens of different breeds

Summary Differences in reaction to exogenous insulin and adrenalin were studied among chickens of Leghorn, White Rock and Rhode Island Red breeds, using level of blood glucose as indicator of the reaction to hormones. It was found that: 1.) The physiological quantity of glucose in blood in chickens of the three breeds ranged from 157 to 194 mg %. 2.) The reaction of chickens to insulin and adrenalin given alternately, measured by changes of blood glucose, differed according to the breed. The smallest reaction to hormones was in Leghorn, the biggest in White Rock. 3.) The chickens of Leghorn and Rhode Island Red breeds, as well as Leghorn and White Rock breeds, differed significantly in maximal glucose level after adrenalin, 4.) The correlation between the normal quantity of blood glucose and the body weight of birds appeared highly significant in cockerels of all three races combined.     

Viability and activity in readily culturable bacteria: a review and discussion of the practical issues

In microbiology the terms viability and culturability are often equated. However, in recent years the apparently self-contradictory expression viable-but-nonculturable (VBNC) has been applied to cells with various and often poorly defined physiological attributes but which, nonetheless, could not be cultured by methods normally appropriate to the organism concerned. These attributes include apparent cell integrity, the possession of some form of measurable cellular activity and the apparent capacity to regain culturability. We review the evidence relating to putative VBNC cells and stress our view that most of the reports claiming a return to culturability have failed to exclude the regrowth of a limited number of cells which had never lost culturability. We argue that failure to differentiate clearly between use of the terms viability and culturability in an operational versus a conceptual sense is fuelling the current debate, and conclude with a number of proposals that are designed to help clarify the major issues involved. In particular, we suggest an alternative operational terminology that replaces VBNC with expressions that are internally consistent.     

Spontaneous chlorophyll mutants of Pennisetum americanum: Genetics and chlorophyll quantities

Summary Thirteen spontaneously occurring chlorophyll deficient phenotypes have been described and their genetic basis was established. Ten of these — white, white tipped green, patchy white, white virescent, white striping 1, white striping 2, white striping 4, fine striping, chlorina and yellow virescent showed monogenic recessive inheritance and the remaining three — yellow striping, yellow green and light green seedling phenotypes showed digenic recessive inheritance. The genes for (i) white tipped green (wr) and yellow virescent (yv) and (ii) patchy white (pw) and white striping 1 (wst 1) showed independent assortment. Further, the genes for white (w), white tipped green (wr) and yellow virescent (yv) were inherited independently of the gene for hairy leaf margin (Hm).In the mutants — white tipped green, patchy white, white striping 1, white striping 2, fine striping, chlorina, yellow virescent, yellow striping, yellow green and light green phenotypes total quantity of chlorophyll was significantly less than that in the corresponding controls, while in white virescent there was no reduction in the mature stage. For nine of the mutants the quantity of chlorophyll was also estimated in F₁'s (mutant x control green). In F₁'s of six of the mutants — white tip, patchy white, chlorina, yellow virescent, fine striping and yellow striping the quantity of chlorophyll was almost equal to the wild type. In the F₁'s of three of the mutants — white striping 1, white striping 2 and light green an intermediate value between the mutant and wild types was observed. In yellow virescent retarded synthesis of chlorophyll, particularly chlorophyll a was observed in the juvenile stage. Reduced quantity of chlorophyll was associated with defective chloroplasts. In the mutants — white tipped green, white virescent, fine striping, chlorina, yellow striping, yellow green and light green defective plastids were also observed. In patchy white secondary destruction of chlorophylls and the presence of defective plastids were found to be associated with reduced chlorophyll quantity at maturity.Paper chromatographic studies of leaf flavonoids revealed some variation between the inbreds, but there were three common spots, 7, 8 and 9, except for PDP in which the spot 8 was absent. Chlorophyll deficient mutants differed from their respective controls in the absence of one or more of the spots present in the controls and in the presence of new spots in some of the mutants.Most of the chlorophyll mutants showed higher survival rate in the Kharif season than in Rabi season which was attributed to the higher mean day temperature and longer day light period in the Kharif season than in Rabi season.     

Evaluation of an exotic maize population adapted to a locality

Summary An exotic Zea mays L. population (Tuxpeno) was adapted to North Carolina conditions by first introducing genes for adaptability from two North Carolina varieties ([(Jarvis X Indian Chief)Tuxpeno]Tuxpeno) including four generations of intermating, and then selecting for adaptability using maturity as the primary measure. The study evaluated selection for adaptability and the diversity available between adapted Tuxpeno and the local varieties, Jarvis and Indian Chief. Analytical procedures were developed to quantify the diversity between populations and the complementation of local varieties by introduced germ plasms. The analyses utilized the specific effects available from the diallel mating design.Three replicate selections responded similarly under simple recurrent mass selection (1/10) for the earliest disease-free plants initially and additionally for plant types (primarily height) in the final generation. The 1/4 local germ plasm permitted rapid adaptation of Tuxpeno gene pool to local conditions. The adapted Tuxpeno populations yielded similarly to the local populations with an average heterosis for grain yield of 28% when crossed to the local populations used as source of genes for adaptability. The diversity found between adapted Tuxpeno lines and these local varieties based on genes affecting grain yield was 1.5 to 2.5 times that measured between the local varieties (Jarvis and Indian Chief). Diversity lost through intergradation with local material was a reasonable investment. Yield genes introduced from Tuxpeno complemented local gene pools through nonadditive, primarily dominance-associated, gene effects. Reassortment of major gene blocks apparently occurred leading to significant divergence among replicate selections involving both additive-associated and dominance-associated gene effects.Paper No. 6355 of the North Carolina Agri. Res. Ser., Raleigh, NC. Research supported in collaboration with the Rockefeller Foundation and CIMMYT, D.F. (Mexico)     

Nucellar callus of ‘Femminello’ lemon,selected for tolerance toPhoma tracheiphila toxin,shows enhanced release of chitinase and glucanase into the culture medium

Phoma tracheiphila is the causative agent of the disease mal secco. Citrus cultivars differ substantially in respect to their sensitivity to the pathogenP. tracheiphila and its toxin. Some cultivars (e.g., Femminello lemon) are inherently sensitive while others (e.g., Tarocco orange) are tolerant. Cell lines derived from nucellar tissue of Femminello, Tarocco and a cell line selected for tolerance to the fungal toxin (Femminello-S) were used to study host-pathogen interaction. Our results showed that calli or conditioned media of Tarocco and Femminello-S inhibited the size of co-cultivated fungal colonies when compared to Femminello. In addition, conditioned medium of Tarocco as well as FemminelloS, but not Femminello, promoted bursting of hyphal tips. A ten-fold increase in chitinase and glucanase enzymatic activity, as evaluated by radiometric assay and laminarin hydrolysis respectively, was detected in Femminello-S extracellular extracts as compared to Femminello. An increase in chitinase was also shown by immunoblot analysis. Our findings suggest a positive correlation between the presence of chitinase and glucanase in the conditioned media of the cultured cells and the tolerance of those cells toP. tracheiphila toxin.     

Immunocytochemical localization of oxytocin in corpora lutea and luteinized cysts from anoestrous ewes stimulated with gonadotrophin-releasing hormone

Summary Anoestrous Romney Marsh ewes with or without progesterone pretreatment were injected with multiple low-doses of gonadotrophin-releasing hormone followed by a single, larger bolus. Blood samples were taken at twelve-hourly intervals for progesterone radioimmunoassay. Ewes were slaughtered on day 3 or 5 after the bolus injection, and the ovaries were collected for histology and immunocytochemical examination for oxytocin-immunocreactivity. The corpora lutea of all ewes killed on day 3 had similar weights and morphology. The ovaries of those ewes which were not pretreated with progesterone also contained some luteinized cysts. Ewes slaughtered on day 5 were separated into 2 groups according to plasma progesterone profiles, which were either rising (normal), or falling after a transitory rise (abnormal). Those ewes pretreated with progesterone all had a normal progesterone profile whereas, of 14 ewes not pretreated with progesterone, 6 were normal and 8 abnormal. Corpora lutea were significantly lighter in the abnormal group and the ovaries of most of these ewes also contained luteinized cysts. All corpora lutea and luteinised cysts showed staining for oxytocin-immunoreactivity although the staining intensity was variable. In corpora lutea from normal ewes oxytocin was restricted to large luteal cells. In addition tissues from abnormal ewes also contained many cells with an atypical elongated shape which stained for oxytocin-immunoreactivity. These results show that progesterone pretreatment is needed for both normal morphological and endocrine development of corpora lutea in anoestrous ewes stimulated with gonadotrophin-releasing hormone.     

Inheritance of resistance to potato viruses Y and A in progeny obtained from potato cultivars containing gene Ry:evidence for a new gene for extreme resistance to PVA

Extreme resistance in cultivated potato (Solanum tuberosum) to potato viruses Y and A (PVY and PVA) conditioned by the presence of Ry genes introduced from Solanum stoloniferum was described by Cockerham (1970). Cockerham detailed a number of genes which controlled a variety of reactions, including extreme resistance to both viruses (i.e. little or no visible reaction of plants and no viral replication following graft and manual inoculation) controlled by gene Ry _sto. In the present study, cvs Pirola and Barbara, which contain a Ry gene, were found to have extreme resistance to PVY isolates from the ordinary (PVY°), veinal necrosis (PVY^N) and potato tuber necrotic ringspot (PVY^NTN) subgroups, and PVA. The inheritance of this phenotype was examined in seedling progenies obtained by crossing Barbara and Pirola with susceptible cultivars. Segregation data for resistance to PVY and PVA in a progeny involving cv Pirola best fitted a genetical model of one gene controlling extreme resistance to both PVY and PVA, although the possibility that there are two genes, each controlling resistance to one virus but closely linked, cannot be excluded. Segregation data from progenies involving cv Barbara best fitted a genetical model in which there are two independent genes, one controlling extreme resistance to PVA and PVY and a second gene controlling extreme resistance to PVA but not to PVY. This previously unrecognised gene conferring extreme resistance to PVA only, should be given the notation Ra in keeping with nomenclature used for other resistance genes.     

Donor tissue and culture condition effects on mesophyll protoplasts of Medicago sativa

Mesophyll protoplasts were produced from clones of two cultivars of Medicago sativa, Rangelander and Regen S. Protoplasts from the Regen S clone generally gave rise to calli while those from the Rangelander clone would undergo direct embryogenesis. Effects of plant growth conditions, donor tissue pretreatment and protoplast culture conditions on mesophyll protoplast production and subsequent development patterns were investigated. The major factor determining whether or not mesophyll protoplasts would be produced from either of the clones was the pretreatment in water of shoots excised from the donor plants. Pretreatment in water containing growth regulators did not alter protoplast production or development in the Regen S clone. Pretreatment of the Rangelander clone shoots with abscisic acid or naphthaleneacetic acid was slightly beneficial to embryo production while pretreatment with benzylaminopurine was detrimental. Altered leaf morphology induced by growth condition changes did not affect mesophyll protoplast production or subsequent development patterns when shoots were pretreated in water. Culture of protoplasts in liquid droplets or solid agar medium increased low density protoplast survival and subsequent embryo production in the Rangelander clone.     

Endogenous abscisic acid and 2-trans-abscisic acid in alternate bearing ‘Wilking’ mandarin trees

The relationship of abscisic acid (ABA) and 2-trans-abscisic acid (t-ABA) to alternate bearing has been examined in Wilking mandarin (Citrus reticulata Blanco) trees. Leaves, stems and buds of trees loaded with fruit (on trees) had 4.3, 6.0 and 2.2 fold higher ABA levels than the corresponding organs from off trees. Leaves had higher ABA levels than stems and buds in both on and off trees. t-ABA was non-detectable in Wilking leaf, stem and bud tissue. Amounts of t-ABA not exceeding 40% of the ABA content, were found in Shamouti and Valencia orange buds and in Wilking fruit peel.The elevated levels of ABA in on tree organs may reflect a stress imposed by the fruit overload.     

High crossability of wild barley (Hordeum spontaneum C. Koch) with bread wheat and the differential elimination of barley chromosomes in the hybrids

Four bread wheat (Triticum aestivum L.) cultivars, Aobakomugi, Chinese Spring, Norin 61 and Shinchunaga, were pollinated with five barley lines/cultivars consisting of three cultivated barley (Hordeum vulgare L.) lines, Betzes, Kinai 5 and OHL089, and two wild barley (Hordeum spontaneum C. Koch) lines, OUH602 and OUH324. Crossability, expressed as the percentage of embryo formation, varied from 0 to 55.4% among the cross combinations. The two wild barley lines generally had a higher crossability than the previously reported best pollinator, Betzes, and some Japanese wheat cultivars were better as the female parent than Chinese Spring. Ninety four hybrid plants were obtained from 250 embryos cultured, and their somatic chromosome numbers ranged from 21 to 36. Eighteen plants were mosaic in chromosome number. Twenty one-chromosome plants appeared most frequently (45.7%) followed by 28-chromosome plants (14.9%). C-banding analysis revealed that elimination of barley chromosomes was mainly responsible for the occurrence of aneuploid plants. In hypoploids derived from Betzes-crosses, chromosome 5 was preferentially eliminated as previously reported, while in hypoploids derived from OUH602-crosses, chromosome 4 was preferentially eliminated. The wild barley line OUH602 may be a useful parent for producing a new wheat-barley addition set because of its high crossability with wheat and a different pattern of chromosome elimination.     

The inheritance of host plant resistance and its effect on the relative infection efficiency of Magnaporthe grisea in rice cultivars

The inheritance of host plant resistance and its effect on the relative infection efficiency for leaf blast was studied in the crosses IR36/CO39 (partially resistant × highly susceptible) and IR36/IR64 (both partially resistant). On the natural scale, gene action appeared multiplicative. After log transformation, additive effects described most of the genetic variation in the cross IR36/CO39, while additive and dominance effects were about equal in magnitude in the cross IR36/IR64. Dominance was towards increased resistance. No transgressive segregation occurred in the cross IR36/CO39. The number of genes that reduce lesion number was estimated to be zero in CO39 and five or more in IR36. The cross IR36/IR64 showed transgressive segregation in both directions, and IR36 and IR64 each contain at least one gene that is not present in the other cultivar. The heritabilities (narrow sense) in the F₂ were low (range 0.06–0.16), while narrow sense heritabilities based on F₃ lines were much higher (range 0.41–0.68). Lesion numbers in F₃ lines were reasonably correlated with those in F₅ progenies derived from the same F₂ plant (r was±0.6 in both crosses). Partial resistance can be effectively improved by selecting the most resistant plants from the most resistant F₃ lines.     

Analysis of the effect of rye chromosomes 4R, 6R and telomeric heterochromatin on 7R on homologous chromosome pairing in pentaploid hybrids (AABBR,AABBD)

Summary Meiotic pairing in Triticum turgidum cv. Ma (4x) with a mean chiasmata frequency of 27.16 per cell was compared with chiasmata frequencies in its hybrids with several triticale strains, Chinese Spring wheat and its addition lines for Imperial rye chromosomes 4R and 6R. In hybrids between Ma and x Triticosecale cv. Rosner the chiasmata frequency was marginally reduced by an average of 1.25%, by 8.8% in hybrids with x Triticosecale cv. DRIRA HH and by 6.7% with DRIRA EE (lacking 90% telomeric heterochromatin from chromosome arm 7RL). In pentaploid hybrids between Ma and T. aestivum cv. Chinese Spring the reduction was an average of 10.30%, while addition lines with rye chromosome 6R reduced chiasmata frequencies by an average of 7.4% and rye addition line for 4R showed the greatest depression in chiasmata frequency in hybrids by a 25.04% reduction. An interchange difference involving long chromosome segments was observed between Ma and Rosner.Contribution No. 819 Ottawa Research Station     

Diallel analysis of submergence tolerance in rice,Oryza sativa L.

Summary The genetics of submergence tolerance in rice was studied in a 10 × 10 half-diallel cross set involving 10 lowland rice varieties, four of which were tolerant (FR13A, FR43B, Kurkaruppan, and Goda Heenati) and the remaining six were nontolerant (RD19, IR42, IR17494-32-1, IR19672-24-3, Jagannath, and CR1009). Estimates of genetic parameters following Hayman's method showed significant additive and nonadditive gene action and the latter appeared to be solely due to dominance. Narrow sense heritability (0.70) indicated that additive gene effects were more important in the inheritance of the trait. Tolerance was dominant over nontolerance and the average dominance was within the range of incomplete dominance. Dominant alleles were more concentrated in the three tolerant parents, FR13A, Kurkaruppan, and FR43B in that order. Wr/Vr graphic analysis suggested the involvement of both major and minor genes. Combining ability analysis by Griffing's method also indicated significance of both additive and nonadditive effects, and the former appeared to be more important than the latter. The hybrids involving FR13A with RD19, IR42, and IR17494-32-1, and those of Kurkaruppan with RD19 and CR1009 appeared to be promising for incorporating an adequate level of tolerance to submergence into lowland rice cultivars.     

Study on the vesicular-arbuscular mycorrhiza of three cultivars of potato (Solanum tuberosum L.)

Summary The establishment and development of vesicular-arbuscular mycorrhizal (VAM) fungi were studied in three cultivars of potato, which differed in susceptibility to Late blight, in a field experiment on a lateritic sandy-loam during two growing seasons (1980 and 1981). The cultivars SSC 1174 (highly resistant) and Kufri Jyoti (resistant) showed an earlier establishment and more rapid development of VAM fungi than up-to-date (highly susceptible). The first mycorrhizal infection in both SSC 1174 and Kufri Jyoti was observed after 12 days in 1980 and 8 days in 1981, whereas in up-to-date it was observed after 19 and 12 days respectively. The mycorrhizal infection increased with the age of the plants in all the three cultivars.     

Inheritance of resistance to the bean-pod weevil (Apion godmani Wagner) in common beans from Mexico

The bean-pod weevil (BPW), Apion godmani Wagner, often causes heavy losses in crops of common bean (Phaseolus vulgaris L.). Farmers need resistant bean cultivars to minimize losses, cut production costs, stabilize seed yield, and reduce pesticide use and consequent health hazards. To design effective breeding methods, breeders need new and better sources of resistance and increased knowledge of their modes of inheritance. We therefore: (1) compared sources of resistance to BPW, (2) studied the inheritance of resistance, and (3) determined whether the sources possess similar or different genes for BPW resistance. The following sources of resistance, originating from the Mexican highlands, were evaluated for 3 years at INIFAP-Santa Lucía de Prias, Texcoco, Mexico: Amarillo 153, Amarillo 169, Hidalgo 58, J 117, Pinto Texcoco, Pinto 168, and Puebla 36. All except Puebla 36 were crossed with the susceptible cultivar Jamapa. Amarillo 153 and Puebla 36 were crossed with another susceptible cultivar, Bayo Mex. The parents, F₁ hybrids, and F₂ populations were evaluated for BPW damage in 1992. Backcrosses of the F₁ of Jamapa/Pinto 168 to the respective susceptible and resistant parents were also evaluated in 1992. All seven resistant accessions were crossed in all possible combinations, excluding reciprocals. The resulting 21 F₁ hybrids and 21 F₂ populations were evaluated for BPW damage in 1994. J 117 had the highest level of resistance to BPW. Pinto Texcoco and Puebla 36 had the highest mean damage score of all seven sources of resistance. The F₁ hybrids between susceptible parents and resistant sources were generally intermediate. Two genes segregating independently controlled the BPW resistance in each accession. One gene, Agm, has no effect when present alone, whereas the other gene, Agr, alone conferred intermediate resistance. When both genes were present, resistance to BPW was higher. Based on mean BPW damage scores, all 21 F₁ hybrids and their F₂ populations, derived from crosses among seven resistant accessions, were resistant. However, data from individual plant damage scores in F₂ populations of Amarillo 169/Pinto 168 and Pinto Texcoco/Pinto 168 suggested that at least one gene in each of the three accessions was non-allelic. Data also indicated that Amarillo 169 had a dominant gene that conferred high levels of BPW resistance, irrespective of the alleles at the other locus; and that Pinto Texcoco and Pinto 168 possessed two different genes for intermediate resistance.     

Genotypic control of pollen plant formation in Nicotiana tabacum L.

Summary Tobacco plants (Nicotiana tabacum L.) of four varieties (Badischer Burley, White Burley, Techne, Kupchunos) were raised at different temperatures and daylengths and the effect of genotype on embryogenic pollen grain formation in situ and on pollen plant formation in anther and pollen cultures from these plants was studied. Genotype controlled embryogenic pollen grain and pollen plant formation by defining productivity under standard growth conditions (long days at 24 °C). Kupchunos was the most productive variety, followed by White Burley, Techne, and Badischer Burley. Furthermore, genotype defined which environmental factor was able to affect embryogenic pollen grain and pollen plant formation and also to which degree. In anther cultures, in addition to these effects, genotype controlled the formation of (an) inhibitory substance(s) in the anther wall in interaction with the plant growth conditions. In Badischer Burley and Techne, inhibitor action could be prevented by isolation of the pollen after one week of anther culture. Finally, direct pollen cultures in Badischer Burley and Techne produced embryos were only when the pollen was isolated from nearly mature anthers, while in White Burley and Kupchunos, embryos also produced at earlier stages and at higher yields. This indicated that genotype controls the time when the embryogenic pollen grains become ready to divide. The results are discussed in relation to strategies to overcome recalcitrance of species and genotypes.     

Ecological theories and Dutch nature conservation

This paper aims to achieve insight into various ecological theories in the Netherlands which have different, and sometimes opposing, views on the conservation of nature. Interviews, publications and archival research brought to light four separate theories: vitalistic/holistic, dynamic, cybernetic and chaos. Diversity is reached through stability according to vitalistic/holistic and cybernetic theories, but through change and instablility according to the dynamic and chaos theories. These two groups are working apart, and continue to have their own ideas. Prediction of the future is only possible with the vitalistic/holistic and cybernetic theories. Ecologists who adhere to these theories feel responsible and able in different ways to change ecological nature towards desirable end goals. The other two theories, dynamic and chaos, appear to be less activist.