Characterization of 13 single nucleotide polymorphism markers for chum salmon

We report the characterization of 13 single nucleotide polymorphism (SNP) genotyping assays for chum salmon (Oncorhynchus keta). These assays are based on the 5′‐nuclease reaction and thus facilitate high‐throughput genotyping with minimal optimization time. Because data generated using these markers may be transported and combined across laboratories, SNPs offer the potential to reduce the amount of redundant work being done in mixture and migratory studies of chum salmon.     

Presence of two glycolytic gene clusters in a severe pathogenic line of Candidatus Phytoplasma asteris

Phytoplasmas are plant-pathogenic bacteria that are associated with numerous plant diseases. We have previously reported the complete genomic sequence of Candidatus Phytoplasma asteris, OY strain, OY-M line, which causes mild symptoms. The phytoplasma genome lacks several important metabolic genes, implying that the consumption of metabolites by phytoplasmas in plants may cause disease symptoms. Here we show that the approximately 30-kb region including the glycolytic genes was tandemly duplicated in the genome of OY-W phytoplasma, which causes severe symptoms. Almost duplicated genes became pseudogenes by frameshift and stop-codon mutations, probably because of their functional redundancy. However, five kinds of genes, including two glycolytic genes, remained full-length ORFs, suggesting that it is advantageous for the phytoplasma to retain these genes in its lifestyle. In particular, 6-phosphofructokinase is known as a rate-limiting enzyme of glycolysis, implying that the different number of glycolytic genes between OY-W and OY-M may influence their respective glycolysis activities. We previously reported that the phytoplasma population of OY-W was higher than that of OY-M in their infected plants. Taking this result into account, the higher consumption of the carbon source may affect the growth rate of phytoplasmas and also may directly or indirectly cause more severe symptoms.     

On the Encystment of Leptomonas sp. (Kinetoplastida: Trypanosomatidae), a Parasite of the Silkworm, Bombyx mori Linnaeus

SYNOPSIS. Promastigotes of Leptomonas sp., a flagellate parasite of the silkworm, Bombyx mori , multiplied by binary fission with the following sequence of events: duplication of the flagellum; division of the kinetoplast and the nucleus; spatial separation of the kinetoplast: and cytokinesis resulting in the formation of 2 daughter promastigotes. In the early stages of encystment, promastigotes aggregated in a rosette and assumed a stumpy form. The nucleus and kinetoplast of the stumpy promastigotes were double, suggesting a possibility of fusion of the organism in the rosette. When most of the promastigotes in the cluster became stumpy, each individual was isolated from the cluster and acquired a thick coat with an acidophilic substance, thus forming a cyst.     

Reassociation of cytoplasmic ribosomal subunits of barley and its virescens mutant to form active hybrids

Polyphenylalamine synthesis by cytoplasmic ribosomes of Gateway barley (Hordeum vulgare) and its virescens single gene nuclear mutant was compared. The cytoplasmic 80S ribosomes were isolated from unimbibed embryo material and the ribosomes were dissociated into their component 60S and 40S subunits by centrifugation through sucrose gradients containing high KCl-to-MgCl₂ buffer. These separated subunits could be reassociated by resuspension in buffer having about equimolar concentrations of MgCl₂ and KCl. Both homologous and heterologous combinations of the subunits reassociated to give monomeric 80S ribosomes, and the derived monomers as well as various combinations of the individual subunits showed equivalent activity in an in vitro system for poly (U)-directed polyphenylalanine synthesis.     

Promotion by Calcium Ions and Cytochalasin D of the Rounding Up Process (Spherulation) of Electrofused Barley Protoplasts and its Relation to the Cytoskeleton

Various agents were tested for the effects on both the electrofusionand the subsequent rounding up (spherulation) of fused protoplastsfrom barley (Hordeum vulgare var. Moor). The microfilament (MF)inhibitor, cytochalasin D (CD), had no effect on the frequencyof fusion, but greatly increased the frequency of spherulation.The effects of CD were rapid, long-lived and maximal at 2 to10 mmol m^–3. Ca²⁺ also promoted spherulation of fusionproducts, whereas phalloidin and the calcium inonophore A₂₃₁₈₇completely abolished the effect of both CD and Ca²⁺. An internalCa²⁺ antagonist, 8-(diethylamino)octyl 3, 4, 5-trimethoxybenzoate(TMB8) at 50 mmol m^–3 also inhibited spherulation withoutaffecting the frequency of fusion and CD could almost completelyreverse its effects. The effects of CD persisted for up to 1h after its removal, whereas the effects of Ca²⁺ and TMB8 wereexerted at the beginning of incubation and were immediatelyabolished by washing. These results indicate that the effectof Ca²⁺ on the formation of spherical fusion products is closelycorrelated with the status of the microfilaments and that theinternal Ca²⁺ concentration and, perhaps, its transient changewhich affects the MF, are intimately involved in the process. Key words: Cytoskeleton, electrofusion, calcium effect     

Discovery of an oak gall wasp (Hymenoptera: Cynipidae) inducing galls on deciduous oak trees in India

We report for the first time the occurrence of an oak gall wasp Andricus mukaigawae (Mukaigawa) (Hymenoptera: Cynipidae) on the deciduous oak Quercus griffithii Hook. F & Thomson ex Miq. in India. Andricus mukaigawae is the only cynipid species that has been observed to induce galls on deciduous oak species in India to date. In addition, this is the first record of a gall wasp species with a distribution extending all the way from the eastern Palearctic region to the Indian subcontinent, suggesting the existence of a close relationship between cynipid faunas on deciduous oak trees in the two regions.