Characterization of microsatellite loci in the western tarnished plant bug,Lygus hesperus Knight (Hemiptera: Miridae)

A microsatellite‐enriched partial genomic DNA library of Lygus hesperus was generated and screened by sequencing. Ten polymorphic microsatellite marker loci were characterized by genotyping 92 insect samples. The observed number of alleles ranged from three to seven with an average of 4.5 (SE ± 0.45), while the effective number of alleles ranged from 1.21 to 3.02 with an average of 2.14 (SE ± 0.20). Significant deviations from Hardy–Weinberg expectations were detected at three loci. Significant linkage disequilibrium was also detected between the loci LhMS2‐54 and LhMS3‐32. Seven of the L. hesperus markers could be transferred to Lygus lineolaris.     

Fluorescence properties of plasma membranes from oats and cauliflower in relation to blue light physiology

Fluorescence properties of plasma membranes from dark-grown oat shoots ( Avena saliva L. cv. Sol II) and from cauliflower inflorescences ( Brassica oleracea L.) were investigated. Along with a flavin (with a possible connection to blue light physiology), a blue fluorescing component was present. The effect of NaN₃, phenyl acetic acid (PAA), KI (flavin inhibitors) and salicylhydroxamic acid (SHAM; inhibitor of e.g. the blue light-induced cytochrome b reduction) were followed with regard to the fluorescence properties of the two components as well as with regard to the light-induced cytochrome b reduction (LIAC). A change in flavin fluorescence and LIAC occurred at about the same concentration of PAA and SHAM, while LIAC was much more sensitive to KI and NaN₃ than was the fluorescence. Rapid freezing and thawing did not change the relative fluorescence emission from the flavin and blue fluorescing component, respectively, but storage at -20°C for one or two days increased the fluorescence, especially from the latter. There did not seem to be a tight coupling between the fluorescence properties of the blue fluorescing component (spectrally similar to a pteridine) and the flavin. Therefore, no conclusions could be drawn concerning their connection in blue light physiology, i.e. in processes such as phototropism.     

Developmental changes of sepiapterin synthase activity associated with a variegated purple gene in Drosophila melanogaster

A variegated position effect on the autonomous gene, purple, has been studied enzymologically in Drosophila melanogaster. Sepiapterin synthase, the enzyme system associated with pr⁺, was examined for activity in different developmental stages of the fly. The results indicate that T(Y:2) pr^c5, cn/pr^c4 cn flies (flies in which pr⁺ has been translocated and which exhibit variegation) have a reduced amount of enzyme activity as compared with both Oregon-R and pr¹ flies. This reduction in activity was not found in larval stages, which suggests that the inactivation process probably occurs in late larval or early pupal stages. The phenotype of the variegated adult has white eyes with red-colored spots and patches where drosopterins occur. The phenotype of the fly carrying the translocation is modified by the presence of additional Y chromosomes. This extends the observation from other systems that extra heterochromatin acts to suppress the variegated position effect. The advantages of studying the variegation by measuring enzyme activity, as well as the phenotypic expression, are several; for example, the developmental time at which variegation occurs may be estimated even though drosopterin synthesis is not occurring.The Oak Ridge National Laboratory is operated by Union Carbide Corporation for the Department of Energy under Contract No. W-7405-eng-26.     

A new reagent which may be used to introduce sulfhydryl groups into proteins, and its use in the preparation of conjugates for immunoassay

A synthesis of the N-hydroxysuccinimide ester of S-acetylthioacetic acid is described. This material is stable when stored dry and has advantages over the currently available reagents used to introduce sulfhydryl groups into a variety of proteins. Proteins modified with this reagent can be used to prepare conjugates for enzyme immunoassay. The conjugation techniques described cause little or no loss of either enzyme activity or antibody titer and function, and the conjugates contain little polymeric material.     

Production of red-flowered plants by genetic engineering of multiple flavonoid biosynthetic genes

Orange- to red-colored flowers are difficult to produce by conventional breeding techniques in some floricultural plants. This is due to the deficiency in the formation of pelargonidin, which confers orange to red colors, in their flowers. Previous researchers have reported that brick-red colored flowers can be produced by introducing a foreign dihydroflavonol 4-reductase (DFR) with different substrate specificity in Petunia hybrida, which does not accumulate pelargonidin pigments naturally. However, because these experiments used dihydrokaempferol (DHK)-accumulated mutants as transformation hosts, this strategy cannot be applied directly to other floricultural plants. Thus in this study, we attempted to produce red-flowered plants by suppressing two endogenous genes and expressing one foreign gene using tobacco as a model plant. We used a chimeric RNAi construct for suppression of two genes (flavonol synthase [FLS] and flavonoid 3′-hydroxylase [F3′H]) and expression of the gerbera DFR gene in order to accumulate pelargonidin pigments in tobacco flowers. We successfully produced red-flowered tobacco plants containing high amounts of additional pelargonidin as confirmed by HPLC analysis. The flavonol content was reduced in the transgenic plants as expected, although complete inhibition was not achieved. Expression analysis also showed that reduction of the two-targeted genes and expression of the foreign gene occurred simultaneously. These results demonstrate that flower color modification can be achieved by multiple gene regulation without use of mutants if the vector constructs are designed resourcefully. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Ommochrome synthesis and kynurenic acid excretion in relation to metamorphosis and allatectomy in the stick insect, Carausius morosus Br.

End products of tryptophan metabolism in Carausius morosus are the ommochromes ommin and xanthommatin in the epidermis, and kynurenic acid in the faeces. During larval and adult life ommochromes and mainly kynurenic acid are formed. The concentration of kynurenic acid in the faeces of adult females is 2.5 times lower than in the larvae and in adult males. Allatectomy on the first day after a larval moult induces a much longer instar (10 days) than normal. After the following moult, the allatectomized animals are transformed into adultoids. The allatectomized and normal larvae produce similar amounts of kynurenic acid and ommochrome during the larval instar. Twenty days after last ecdysis, the ommochrome content in adult and adultoids is increased. In the faeces of adultoids, however, the concentration of kynurenic acid is higher than in normal female adults, but lower than in males and larvae.