Three glucose 6-phosphate dehydrogenase variants found in Japan

Summary Three Japanese glucose 6-phosphate dehydrogenase (G6PD) variants were investigated. G6PD Mediterranean-like had markedly decreased activity, normal electrophoretic mobility, low Km G6P, low Km NADP, increased utilization of all three substrate analogues (2-deoxy-G6P, Gal-6P, and deamino-NADP) and slightly decreased heat stability and slightly biphasic pH curve. G6PD Ogori had markedly decreased activity, but otherwise normal characteristics. G6PD Hofu had moderately decreased activity, normal electrophoretic mobility, slightly reduced Km G6P, normal Km NADP, normal utilization of 2-deoxy-G6P and Gal-6P, but increased utilization of deamino-NADP and normal heat stability as well as normal pH curve.     

Quantitative electron probe microanalysis of leech photoreceptors

Summary The photoreceptive microvilli in the visual cells of the leech protrude into a large intracellular vacuole which is but an extracellular compartment (ionic composition unknown), because it communicates with the extracellular space by narrow ( 20 nm) clefts (septate junctions) of unknown permeability properties. Application of Thiéry's cytochemical silver proteinate method reveals that the vacuole contains carbohydrate-rich material. We used electron probe microanalysis of dry, ultrathin cryosections to determine quantitatively the elemental (K, Na, Cl, Mg, Ca, P, S) composition of the cytoplasm, vacuole and extracellular space.The composition of the vacuole is similar to that of the extracellular space, as shown by the comparable Na/K (11 to 13) and K/Ca (1.8 to 2.2) ratios in these two compartments. There are neglible concentration gradients for Na, K and Cl between vacuole and extracellular space. The vacuole has a high S content and a relatively large deficit of Cl compared to [Na]+[K]+2 [Ca]. Thus the data indicate that the vacuole is in ionic communication with the extracellular space and contains sulfonated glycoprotein(s) that can partially exclude Cl; electroneutrality is maintained in part by these organic anions. The cytoplasmic K concentration (393±30 mmol/kg dry wt) is comparable to that in other nerve cells. The cytoplasmic Cl concentration (216±14 mmol/kg dry wt) is relatively high: significantly (P<0.001) higher than the cytoplasmic Na (130±15 mmol/kg dry wt). The high cytoplasmic Cl content is in excess of that predicted by passive distribution, and suggests the operation of a Cl pump.     

Identification of a high-molecular-weight subunit of glutenin whose presence correlates with bread-making quality in wheats of related pedigree

Summary The subunit composition of glutenin was analysed by SDS-polyacrylamide-gel electrophoresis using two varieties of contrasting pedigrees. Maris Widgeon, a variety of good bread-making quality, was shown to contain 2 glutenin subunits not present in Maris Ranger, a much higher yielding variety that is unsuitable for making bread. A third subunit was only found in Maris Ranger glutenin. To determine if any of these subunits are directly related to bread-making quality, 60 randomly-derived F₂ progeny from a Maris Widgeon x Maris Ranger cross were analysed for bread-making quality and for glutenin subunit composition. A strong correlation was demonstrated between the presence of one of the two subunits inherited from Maris Widgeon, and quality. This subunit (termed subunit 1 glutenin) had an approx. mol. wt. of 145,000. It was also found in Maris Freeman, a bread-making variety selected from the same cross previously made in 1962. In further crosses involving Maris Widgeon or its descendants, more bread-making varieties have been produced in the last decade at the Plant Breeding Institute, Cambridge and all but one have inherited glutenin subunit 1. The subunit has been traced back through Holdfast to White Fife, a Canadian hard spring wheat of excellent breadmaking quality. Some 67 varieties were screened for the presence of glutenin subunit 1 and it was found in 31% of them. Several unrelated varieties of good bread-making quality did not contain subunit 1 glutenin.     

Immature embryo rescue,culture and seedling development of acid citrus fruit derived from interploid hybridization

Interploid sexual hybridizations were completed in 2001 and 2002 between seven lemon (Citrus limon(L.) Burm. f.) varieties, Key lime (C. aurantifolia (Cristm.) Swing), Palestine sweet lime (C. imettioides Tan.), Lakeland limequat (C. aurantifolia x Fortunella japonica (Thumb.) Swing.), and Etrog citron (C. medica L.) as diploid progenitors and four allotetraploid somatic hybrids (Key lime + Valencia orange, Hamlin orange + Femminello lemon, Valencia orange + Rough lemon, and Valencia orange+ Femminello lemon) in efforts to generate improved seedless triploid acid fruit hybrids. Efficient recovery of triploid progeny from such crosses requires embryo rescue to avoid embryo abortion due to endosperm failure. Germination of rescued genetically diverse immature embryos was induced on two culture media (EME and Gamborgs B5), with two sucrose concentrations (50 or 70 g l^–1). All media contained 0.5 g l^–1 malt extract and 4.50 M GA₃. Germination of globular, heart and torpedo shaped embryos (defined as small embryos) was significantly (p < 0.05) affected by medium and genotype. Gamborgs medium induced 82.89% germination. Of germinated embryos, 11–65% developed into normal plants with differences among crosses. Cotyledonary embryos (defined as immature embryos with fully developed cotyledons) germinated and developed into normal plants at higher rates than less-developed embryos. In efforts to improve the efficiency of plant recovery, small embryos from Todo el año × HF and Lisbon × HF crosses conducted during 2002 were rescued and cultured on three media (MS, Gamborgs, and RMA) for comparison. Media did not significantly affect the proportion of normal plant recovery.     

Patterns of direct and indirect embryogenesis from mesophyll protoplasts of Medicago sativa

Clones of three cultivars of Medicago sativa (Rambler, Regen S and Rangelander) were used as sources of mesophyll protoplasts. Although all three clones readily produced protoplasts, the subsequent development patterns in culture varied greatly among genotypes, with protoplasts from Regen S and Rambler forming calli which could be induced to form embryos, and protoplasts from Rangelander undergoing direct embryogenesis. Protoplasts of Regen S exhibited high rates of division while those of Rangelander tended to aggregate with only a few cells per aggregate surviving. The surviving cells gave rise to proembryos within the aggregates; these proembryos developed into differentiated embryos after 5–7 weeks of culture. Based on the initial protoplast population, the efficiency of embryo formation averaged 0.13% and ranged from 0.001–0.4%. Observations during the early stages of culture indicated that cell aggregation was a prerequisite for direct embryogenesis.     

Heritable variation in the phaseolin protein of nondomesticated common bean,Phaseolus vulgaris L.

Summary Crude protein extracts from single seeds of nondomesticated Mexican bean accessions were analysed by SDS polyacrylamide gel electrophoresis for variability in phaseolin protein. Six new phaseolin types; M1, M2, M3, M4, M5, M6, which contained polypeptides within the same range of molecular weights (51,000 to 45,000 daltons) as occur in the S, T and C phaseolin types of cultivated beans were identified. No T and C types were found among the non-domesticated Mexican accessions, and the S type occurred in less than 7% of the seeds screened. Genetic analyses of F₂ progenies from crosses between Sanilac (S), and five of the M types showed that each M phaseolin phenotype was allelic to the S type and expressed codominantly.     

Towards a pluralistic concept of function function statements in biology

The meaning of function statements is not clear. Several authors have come up with different explications. By interviewing biologists I tried to get a picture of how they think about function. Two explications of Feature X of organism S has function F came to the fore: (1) X contributes to F and F contributes to survival/reproduction of S and (2) X does F and that contributes to the evolutionary development of X in S via natural selection. Most biologists also related function to adaptation. Gould and Vrba criticize the ordinary use of adaptation in biology. They propose to use it only in the sense of features developed by natural selection for their current role and to use exaptation for features enhancing fitness, but not developed for this by natural selection. This, however, leaves a terminological gap, because as a consequence only effects of adaptations are functions. Effects of exaptations and effects which are not beneficial, like the production of heart sounds, are placed on the same level. That is not in accordance with the practice of biology. That is why a distinction is made between general, adaptive and exaptive functions: function as a pluralistic concept.Revised version of an earlier paper, published in Dutch in Kennis en Methode, November 1988.     

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.     

Heterochromatin banding in the genus Paris

The heterochromatin content of new accessions of the genus Paris have been studied using C banding and Q banding techniques. Supernumerary chromosomes in two accessions are shown to differ in their heterochromatin content. The results are related to previous cytogenetic work in the genus Paris.     

Inheritance and linkage of isozyme loci in almond

The segregation of seven isozyme marker genes was investigated using eight controlled crosses in almond. The cultivar Nonpareil was the maternal parent in all crosses. Pollination was achieved using eight different cultivars, and a total of 3200 individual kernels were assessed. For each isozyme the goodness-of-fit test was used to test for departure from the expected frequencies assuming Mendelian inheritance. Given a higher than expected number of significant results for individual isozymes, independent segregation between pairs of isozymes was tested using the chi-square statistic on the resulting two-way contingency tables. In all crosses a highly significant association (P value< 0.001) was observed between (1) the AAT- 1 and IDH isozymes loci and (2) the LAP-1 and PGM-2 isozymes loci, which leads to the conclusion that the respective isozyme pairs are linked.In addition, a significant association (P value < 0.001) was observed between LAP-1 and GPI-2 when the pollen sources were Fritz, Mission, or Price, but this could not be tested for the remaining five pollen sources, Carmel, Grant, Keane, Ne plus Ultra, Peerless, because they are homozygous at these loci. If LAP-1 is linked with GPI-2 and PGM-2, it might be expected that we should find evidence of linkage between GPI-2 and PGM-2. The lack of a significant association between these two isozymes suggests that LAP-1 is located centrally on the chromosome. These three pairs of linked loci are the first to be reported in almond.     

Involvement of abscisic acid in bulb dormancy of Allium wakegi Araki. II. A comparison between dormant and nondormant cultivars

The content of abscisic acid (ABA) in bulbs of two Allium wakegi Araki cultivars, Kiharabansei No. 1 (dormant type) and Ginoza (nondormant type), was similar and changed similarly during the development and storage of the bulbs. It increased during bulb development, reached a maximum shortly after bulb harvesting, and gradually decreased during bulb storage. The bulbs of Kiharabansei No. 1 showed dormancy correlated with the change in ABA content, but those of Ginoza did not show significant dormancy throughout the experimental period. The ABA content in the buds of dormant bulbs of Kiharabansei No. 1 did not change after planting of bulbs, but that of nondormant bulbs of Ginoza planted on the same day rapidly decreased after planting. Application of ABA to bulbs delayed sprouting of both cultivars, but dormant bulbs of Kiharabansei No. 1 had higher sensitivity to ABA than the bulbs of Ginoza or the bulbs of Kiharabansei No. 1 partly released from dormancy. These results suggest that the decrease in the ABA content after planting (watering) and low sensitivity to ABA are correlated with the nondormancy of Ginoza.     

Genetic analysis of resistance to whitebacked planthopper in twenty-one varieties of rice,Oryza sativa L.

Summary The inheritance of resistance to whitebacked planthopper Sogatella furcifera (Horvath) was studied in 21 rice varieties. Reactions of F₁; F₂ and F₃ progenies of the crosses of 21 resistant varieties with the susceptible variety TN 1 revealed that a single dominant gene governs resistance in Mushkan 41, Santhi, Siahnakidar 195, SM2-34, Tirisurkh 251, Zirijowaian 245, 18, 24A, 39, 76 S, 78, 180, 213 B, 267, 293, CI 6037-4, NP97, S39 JKW and Bansphul. In varieties 65 and 274 A, resistance is governed by one dominant and one recessive gene which segregate independently of each other. Tests for allelism with the Wbph 1 gene originally identified in N 22 revealed that the dominant gene present in all the test varieties is the same as Wbph 1. Further studies are required to determine the allelic relationships of the recessive gene found in varieties 65 and 274 A.     

Are ‘multiple cross-multiple pollen hybrids’ an answer for productive populations in Brassica campestris (var.) Brown Sarson?

Summary A set of 167 mucromphs was evaluated in their F₁ generation for seven plant, four plot and five ratio characters. Methods of characterizing the parents and the hybrids on the basis of combining ability effects described in the first part were found to be efficient in identifying desirable cross combinations for pedigree breeding or generating composite populations. Order effects of multiple-pollen combinations were found to be potent for a number of character components. High x Low cross-combinations were found to produce a high frequency of heterotic crosses followed by High x High. Selected biparental progenies, single crosses, three-way crosses and elite varieties were successful female parents and combinations of pollen from two varieties, one variety and three varieties were successful male parents, in that order, in producing significant heterosis in mucromphs. The relationship between general and specific combining ability on the one hand and realised heterosis on the other was discussed.     

Hydrolysis of 2-substituted aryl and heteroaryl alkanoates by Candida rugosalipase

sThe hydrolysis of several esters catalyzed by lipase of Candida rugosa was used to analyse the interaction between the ester substrate and the active site and the geometry and steric restrictions of alk, ar and h subsites. Using 4-R-C H -CH(R)-COOEt and ethyl trans-cinnamate, the presence of a low electronic density zone in the ar pocket is described, the dimensions of the pocket produced by Phe-296 and Leu-297 in the alk subsite and the size of the h subsite are described.     

Aislamiento de antigenos cationicos de Paracoccidioides brasiliensis mediante intercambio ionico

Resumen El procedimiento de intercambio iónico empleado en este trabajo ha mostrado ser un método eficiente, sencillo y rápido, para eliminar las fracciones antigénicas aniónicas de un extracto crudo deP. brasiliensis.Su empleo permitió la obtención de un antígeno purificado que contiene algunas de las fracciones catiónicas del extracto crudo. El antígeno responsable de la formación del arco E fue identificado en el extracto purificado, mediante análisis inmunoelectroforético.     

Amino acid profiles in some scented rice varieties

Summary Twelve scented (basmati) and one non-scented variety were analysed for their amino acid composition. The essential amino acid profiles of scented varieties when compared with non-scented, revealed that these varieties exhibited higher values, which ranged from 2.82 to 4.86 gm/100 gm protein for lysine, 1.92 to 3.13 for methionine, 1.67 to 4.23 for tyrosine, 3.65 to 4.91 for phenylalanine, 5.50 to 8.95 for leucine, 2.25 to 3.40 for isoleucine, 2.84 to 3.46 for threonine, 3.36 to 5.33 for valine. When these values were compared to FAO recommended standards, it was observed that most of the scented varieties had comparable or superior values, while varieties such as, Type 3, Basmati sufaid 100, Likitimachi, Randhunipagalu and Basmati 370 showed superior lysine, phenylalanine, leucine, and methionine content. These observations suggest that the scented varieties posses better amino acid profiles and exhibit superior nutritional qualities, which could be utilised in breeding varieties with improved amino acid composition.     

Production of pineapple plants in vitro

In vitro culture of pineapple (Ananas comosus) was studied to determine the efficiency of axillary bud culture for rapid propagation of several cultivars. The technique used maximizes the success rate of various steps in the production of pineapple plants. Rapid mass multiplication of plantlets started 9 months after explanting with a significant log phase. The number of plantlets obtained from the culture of a single bud by the thirteenth month ranged from 210 to 380 for Perolera; 300 to 350 for PR-1-67; and 40 to 85 for Smooth Cayenne. The method permits culture of a range of pineapple cultivars. Little morphological variation was observed in young regenerated plants.     

The “Bantu Clinic”: A Genealogy of the African Patient as Object and Effect of South African Clinical Medicine, 1930–1990

This paper is about power, medicine andthe identity of the African as a patient of westernmedicine. From a conventional perspective and asencoded in the current quest for wholeness thatcharacterises South African biomedical discourse, theAfrican patient – like any other patient – has alwaysexisted as an authentic and subjectified being, whosetrue attributes and experiences have been denied bythe mechanistic, reductionistic and ethnocentricpractices of clinical medicine. Against this liberalhumanist perspective on the body as ontologicallyindependent of power, this paper offers a Foucaultianreading of the African patient as – like any otherpatient – contingent upon the force relations immanentwithin and relayed through the clinical practices ofbiomedicine. A quintessential form of disciplinarymicro-power, these fabricate the most intimaterecesses of the human body as manageable objects ofmedical knowledge and social consciousness to makepossible the great control strategies of repression,segmentation and liberation that are the usual focusof conventional investigations into the place andfunction of medicine in society. Since the 1930s whenthe African body first emerged as a discrete object ofa secular clinical knowledge, these have repeatedlytransformed the attributes and identity of the Africanpatient, and the paper traces this archaeology ofSouth African clinical perception from then until the1990s to show how its quest for wholeness is not anend point of discovery or liberation, but merelyanother ephemeral crystallization of socio-medicalknowledge in a constantly changing force field ofdisciplinary power.     

A theory of the origin of life

Life on Earth is essentially nucleic acids (NAs) influencing peptide synthesis such that NA replication is favored. It is proposed that the ability to synthesize polypeptides evolved gradually — one peptide bond at a time. The proposed evolution of the peptide synthesis apparatus begins with a transfer NA (tNA) which catalyzes the transfer of activated amino acids to accessible amino groups in its environment. The resulting capped molecules (with single amino acid caps) in turn favor NA replication. The proposed evolution of the peptide synthesis apparatus from the tNA onward is characterized by a progressive increase in the number of amino acids per cap: two tNAs jointly produce a dipeptide cap, three tNAs jointly produce a tripeptide cap, etc. Messenger NAs evolve because they can specify the composition and sequence order of the peptide caps. Lastly, ribosomal NAs evolve. The origin, expansion, and standardization of the genetic code are discussed. It is proposed that the present triplet code evolved by a process of codon length refinement, and that originally codons of varying lengths were allowable, as were unassigned bases between codons. An environmental supply of activated compounds for early evolving entities is proposed. An environmental NA replication process via single template-directed bond formation events is proposed. An environmental retention and redistribution process is proposed to have acted as a functional substitute for the cell wall and cell division of early evolving entities.     

Exploiting selective genotyping to study genetic diversity of resistance to Fusarium head blight in barley

Numerous barley cultivars from around the world have been identified as potential sources of Fusarium head blight (FHB) resistance genes. All of these cultivars exhibit partial resistance, and several mapping studies have shown that resistance to FHB is controlled by multiple genes. Successful development of barley cultivars with high levels of FHB resistance will require combining genes from multiple sources. We characterized five potential new sources of FHB resistance (AC Oxbow, Atahualpa, HOR211, PFC88209, and Zhedar#1) to determine if they contain new FHB resistance genes. Cluster analysis, using a set of 80 SSR markers distributed throughout the genome, showed that most of the new sources of resistance were not similar to three cultivars that have been used in previous FHB mapping studies (Chevron, Frederickson, and Gobernadora), with Atahualpa and HOR211 being the most dissimilar. By selective genotyping, we determined whether markers linked to six known FHB resistance quantitative trait loci (QTLs), discovered in other genotypes, explained variation for resistance in advanced breeding populations created from the new sources of resistance. Markers linked to four of the six known QTLs were associated with FHB severity in at least one of the populations. However, none of the six QTL regions were associated with variation for FHB severity in populations derived from crosses that utilized sources of resistance HOR211 or PFC88209. Selective genotyping is an efficient method for breeders to utilize current QTL information about disease resistance to search for new resistance genes.