Semi-lethality in hybrid offspring of wheat

Summary Seven of the wheat crosses which were performed in 1954 and 1955 produced a uniform semi-lethal F₁. Among these were four combinations with the spring wheat Koga and two with the Turkish winter wheat Eskischir. The degree of withering in the F₁ appeared to be dependent on the variety with which Koga or Eskischir were combined. In the F₂ of the Koga crosses carried out in 1954 a 9 : 7 ratio of semi-lethals and normal plants was found. The almost continuous gradation in semi-lethality within the group of semi-lethal plants of every F₂ was conspicuous.The facts are explained as follows: Two complementary genes determine the semi-lethality as such, while modifying genes are responsible for the different degrees of semi-lethality of the different F₁'s and for the variation in degree of semi-lethality within every F₂. In the discussion this explanation is given in detail.It is pointed out that it is perhaps possible, with the aid of the phenomenon of semi-lethality, to discover or confirm relationships between species and/or varieties.Finally it is suggested that the rejection of F₁'s with withering symptoms is premature.     

In vivo antioxidant activities of essential oils and their constituents from leaves of the Taiwanese Cinnamomum osmophloeum

Cinnamomum osmophloeum Kaneh is an indigenous tree species in Taiwan. In this study, phytochemical characteristics and antioxidant activities of the essential oils and key constituents from the leaves of two C. osmophloeum clones were investigated. The two trees possess two chemotypes, which were classified as the cinnamaldehyde type and camphor type. We demonstrated that the essential oils from C. osmophloeum leaves exerted in vivo antioxidant activities in Caenorhabditis elegans. In addition, trans-cinnamaldehyde and D-(+)-camphor, which respectively represent the major compounds in the cinnamaldehyde-type and camphor-type trees, exerted significant in vivo antioxidant activities against juglone-induced oxidative stress in C. elegans. Moreover, expressions of antioxidative-related genes, including superoxide dismutase (SOD) and glutathione S-transferase (GST), were significantly induced by trans-cinnamaldehyde and D-(+)-camphor from C. osmophloeum leaves. Our results showed that the essential oils from C. osmophloeum leaves and their major compounds might have good potential for further development as nutraceuticals or antioxidant remedies.     

Population genetics of red imported fire ant in Taiwan

In the case of recently established populations of Solenopsis invicta in Taiwan,analysis of genetic variation may provide various dimensions regarding the historical demographic events of this invasive species,which represents a novel opportunity to study the genetic consequences of invasiveness over an ex- tremely short time period.Here we describe genetic structure of two introduced S.invicta populations, Taoyuan and Chiayi,in Taiwan using two classes of markers,nuclear(microsatellites)and mitochondrial (mtDNA)genomes.Pronounced regional differentiation inferred from either AMOVA or Bayesian clustering approach at both genomes suggests that the two populations most likely originate from separate introductions. Furthermore,significant mtDNA but not nuclear differentiation between sympatric social forms suggests two scenarios that interform gene flow is mainly mediated by males,and queens of each form commonly fail to become egg-layers of alternate form.Isolation by distance(IBD)obtained from microsatellites is absent in monogynes,indicating sexuals of this form retain the superior dispersal ability to homogenize the nuclear sig- nature among spatially isolated areas;however,lack of IBD in less vagile polygyne may result from frequent human mediated jump dispersal that erodes the geographical restrictions of genetic exchange.The patterns observed here not only provide insights into how social organization influences the interform gene flow but also reinforce different breeding strategies pursued by two forms in the character of shaping the genetic varia- tion at two levels of genomes.     

Use of Enzymes for the Separation of Protein from Rice Flour

When rice flour was treated with heat stable α-amylases, the effectiveness of protein separation increased with increased temperature. Depending on the enzyme, treatment at 90°C for 45 min resulted in protein contents of 47–65% for the insoluble fraction. Prior gelatinization enhanced the effectiveness of the enzyme reaction but was undesirable because the increased viscosity and gelation could cause difficulties in the processing operation. Follow-up treatment with other carbohydratehydrolyzing enzymes, such as glucoamylase, cellulase, and hemicellulase further increased the protein content up to 76% for the insoluble fraction. The subunit structure of the isolated proteins, based on electrophoretic analysis, remained practically unchanged after the treatment. The limited solubility and emulsion activity of rice protein were also unchanged.