Occurrence of chrysanthemum virescence caused by “<Emphasis Type="Italic">Candidatus</Emphasis> Phytoplasma aurantifolia” in Okinawa

In 1999, a disease of chrysanthemum [Dendranthema grandiflorum (Ramat.) Kitamura], characterized by virescence of flowers, occurred in Okinawa Prefecture. The causal agent was identified as “Candidatus Phytoplasma aurantifolia” based on 16S rDNA sequencing. The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under accession number AB247462.     

Age trends in the genetic parameters of wood density and the relationship with growth rates in hybrid larch (Larix gmelinii var. japonica × L. kaempferi) F1

Age trends in variance components and heritability of overall wood density, earlywood and latewood density, and latewood proportion were investigated in 29-year-old trees of 19 full-sib families of hybrid larch (Larix gmelinii var. japonica × Larix kaempferi) F₁. The age–age correlation and optimum selection age for these traits were also estimated and genetic and phenotypic correlations between wood density and radial growth rate were calculated for each growth ring. Intraring wood density data were obtained using X-ray densitometry. The coefficient of additive genetic variance was stable over all ages, whereas the coefficient of environmental variances gradually decreased with increasing age, resulting in increases in heritability estimates with age for overall density. The latewood proportion had the highest heritability estimates at all ages, ranging from 0.44 to 0.66. Overall density and its various components at 28 years of age showed strong genetic correlations with their respective traits at all younger ages. Optimum selection ages for the wood density traits ranged from 8 to 14 years, at which point maximum gain efficiencies per year were obtained. There were negative correlations between wood density and radial growth rate at early ages, although these relationships tended to be weaker with increasing age. These results suggest that selection at a young age is effective for wood density, but particular care must be taken in selecting trees with an improved radial growth rate because rapid growth will result in a low-density wood product, especially in the early growth period.     

The Physcomitrella genome reveals evolutionary insights into the conquest of land by plants

We report the draft genome sequence of the model moss Physcomitrella patens and compare its features with those of flowering plants, from which it is separated by more than 400 million years, and unicellular aquatic algae. This comparison reveals genomic changes concomitant with the evolutionary movement to land, including a general increase in gene family complexity; loss of genes associated with aquatic environments (e.g., flagellar arms); acquisition of genes for tolerating terrestrial stresses (e.g., variation in temperature and water availability); and the development of the auxin and abscisic acid signaling pathways for coordinating multicellular growth and dehydration response. The Physcomitrella genome provides a resource for phylogenetic inferences about gene function and for experimental analysis of plant processes through this plant's unique facility for reverse genetics.     

Cleavage of proBDNF by tPA/plasmin is essential for long-term hippocampal plasticity

Long-term memory is thought to be mediated by protein synthesis-dependent, late-phase long-term potentiation (L-LTP). Two secretory proteins, tissue plasminogen activator (tPA) and brain-derived neurotrophic factor (BDNF), have been implicated in this process, but their relationship is unclear. Here we report that tPA, by activating the extracellular protease plasmin, converts the precursor proBDNF to the mature BDNF (mBDNF), and that such conversion is critical for L-LTP expression in mouse hippocampus. Moreover, application of mBDNF is sufficient to rescue L-LTP when protein synthesis is inhibited, which suggests that mBDNF is a key protein synthesis product for L-LTP expression.     

The slit receptor EVA-1 coactivates a SAX-3/Robo mediated guidance signal in C. elegans

The SAX-3/roundabout (Robo) receptor has SLT-1/Slit-dependent and -independent functions in guiding cell and axon migrations. We identified enhancer of ventral-axon guidance defects of unc-40 mutants (EVA-1) as a Caenorhabditis elegans transmembrane receptor for SLT-1. EVA-1 has two predicted galactose-binding ectodomains, acts cell-autonomously for SLT-1/Slit-dependent axon migration functions of SAX-3/Robo, binds to SLT-1 and SAX-3, colocalizes with SAX-3 on cells, and provides cell specificity to the activation of SAX-3 signaling by SLT-1. Double mutants of eva-1 or slt-1 with sax-3 mutations suggest that SAX-3 can (when slt-1 or eva-1 function is reduced) inhibit a parallel-acting guidance mechanism, which involves UNC-40/deleted in colorectal cancer.     

Effects of high ambient temperature on plasma metabolomic profiles in chicks

Exposure to high ambient temperature is detrimental to the poultry industry. To understand the influence from a metabolic perspective, we investigated the effects of exposure to high ambient temperature on plasma low‐molecular‐weight metabolite levels in chicks using gas chromatography/mass spectrometry‐based non‐targeted metabolomic analysis. Heat exposure for 4 days suppressed growth and food intake. Of the 92 metabolites identified, the levels of 29 decreased, whereas the levels of nine increased. We performed an enrichment analysis on the identified metabolites and found 35 candidates for metabolic processes affected by heat exposure. Among them, the sulfur amino acid metabolic pathway was clearly detected and the levels of the following related metabolites were decreased: cystathionine, cysteine, cystine, homocysteine and hypotaurine. Changes in the kynurenine pathway in tryptophan metabolism, which is linked to the immune system and oxidative stress, were also observed: kynurenine and quinolinic acid levels increased, whereas nicotinamide levels decreased. These results suggest the possible involvement of various metabolic processes in heat‐exposed chicks. Some of these metabolites would be important to understand the mechanism of biological responses to high ambient temperature in chicks.     

A transdisciplinary research of coastal fisheries co-management: the case of the hairtail <Emphasis Type="Italic">Trichiurus japonicus</Emphasis> trolling line fishery around the Bungo Channel,Japan

Under the coastal fisheries co-management regime in Japan, local fishers play important roles in deciding on and implementing local management measures. Therefore, using the case study of a hairtail trolling line fishery, we conducted a transdisciplinary research with fishers, processors, government officers, etc. Taking social and biological factors into account, we defined management criteria and targets (resource, economic, human community, and local food culture) in collaboration with local fishers. We chartered local fishing vessels to determine parameters that were easily understood by local fishers. We established a local consultative committee comprising fishers, processors, and distributors, and developed a fish distribution strategy to nurture the local hairtail food culture. The integrated effects of various management scenarios were evaluated by the operating model. We found that co-ordinated management by both the trolling line fishery and purse seiners in the neighbouring prefecture was required to achieve targets. Two realistic scenarios are recommended: a conservative scenario that could achieve targets even with few strong year classes, and an adaptive scenario that protects strong year classes, but relies on a higher frequency of these. We shared these results with the local fishers and government officers, which led to actual improvements in management measures.     

Conservation of small hairtail <Emphasis Type="Italic">Trichiurus japonicas</Emphasis> by using hooks with large artificial bait: effect on the trolling line fishery

Overfishing has reduced the stock of hairtail Trichiurus japonicus around the Bungo Channel, Japan. To determine whether using larger bait in the trolling line fishery could avoid catching small/undersize hairtail, we developed and trialled a new large artificial bait (a soft plastic bait, 6 inches long). A traditional lure with natural bait (type-1), a new lure of the new artificial bait hook without natural bait (type-2), and a new lure with natural bait (type-3) were tested in fishing operations around the Bungo Channel. Compared with type-1, type-2 and type-3 caught fewer undersized and immature female individuals. The number of fish caught, yield, and composition of commercial size grades per recruitment were calculated from field data for each lure and compared. The catch sizes (number of fish per recruitment) were smaller for type-2 and type-3 than for type-1, but yield per recruitment was higher for type-3 than for type-1. Compared with type-1, type-2 and type-3 caught more large individuals, which are more valuable. The newly developed artificial bait conserves hairtail stocks by targeting larger fish, which is economically beneficial for the hairtail trolling line fishery.