Studies on Leaf Surface Lipid of Tobacco III. Compositional Change in Alkane during Growth and Senescence of Tobacco Leaves

Alkane is the major constituent of epicuticular wax universally distributed in plants. Tobacco leaves contained 5–10 mg of alkane per 1000 cm². The content gradually increased with leaf age. Leaves on the upper stalk contained more alkane than those on lower stalk. Components with carbon numbers from 27 to 33 occupied more than 98 % of the total alkane content. In relative ratios of alkane components, anteiso-C₃₀ and normal-C₃₁ were most drastically and increased, respectively, with leaf age regardless of stalk position. On the other hand, normal-C₂₉ and normal-C₃₃ increased and decreased, respectively, from the upper to lower stalk positions without being affected by leaf age. These results suggest the possible use of alkane composition as an index of leaf maturity and stalk position, for example, the ratio of anteiso-C₃₀/normal-C₃₁ for maturity and normal-C₃₃/normal-C₂₉ for stalk position.     

Production of 10-ketostearic acid from oleic acid by a strain of Flavobacterium sp. 12-4A

Summary A new Flavobacterium sp., strain 12-4A, produces solely 10-ketostearic acid (KSA) from oleic acid (OA) in growing cultures. Under optimized conditions 14 mg/ml of KSA was produced from 25 mg/ml of OA after 3 days of cultivation at 30°C.     

Collaborative environmental DNA sampling from petal surfaces of flowering cherry <Emphasis Type="Italic">Cerasus</Emphasis> × <Emphasis Type="Italic">yedoensis</Emphasis> ‘Somei-yoshino’ across the Japanese archipelago

Recent studies have shown that environmental DNA is found almost everywhere. Flower petal surfaces are an attractive tissue to use for investigation of the dispersal of environmental DNA in nature as they are isolated from the external environment until the bud opens and only then can the petal surface accumulate environmental DNA. Here, we performed a crowdsourced experiment, the “Ohanami Project”, to obtain environmental DNA samples from petal surfaces of Cerasus?×?yedoensis ‘Somei-yoshino’ across the Japanese archipelago during spring 2015. C. × yedoensis is the most popular garden cherry species in Japan and clones of this cultivar bloom simultaneously every spring. Data collection spanned almost every prefecture and totaled 577 DNA samples from 149 collaborators. Preliminary amplicon-sequencing analysis showed the rapid attachment of environmental DNA onto the petal surfaces. Notably, we found DNA of other common plant species in samples obtained from a wide distribution; this DNA likely originated from the pollen of the Japanese cedar. Our analysis supports our belief that petal surfaces after blossoming are a promising target to reveal the dynamics of environmental DNA in nature. The success of our experiment also shows that crowdsourced environmental DNA analyses have considerable value in ecological studies.     

Synthesis and evaluation of a [18F]formyl–Met–Leu–Phe derivative: A positron emission tomography imaging probe for bacterial infections

The tripeptide formyl–Met–Leu–Phe (fMLF) is a prototype of N-formylated chemotactic peptides for neutrophils owing to its ability to bind and activate the G protein-coupled formyl peptide receptor (FPR). Here, we developed an ¹⁸F-labeled fMLF derivative targeting FPR as a positron emission tomography (PET) imaging probe for bacterial infections. The study demonstrates that the fMLF derivative fMLFXYk(FB)k (X?=?Nle) has a high affinity for FPR (Ki?=?0.62?±?0.13?nM). The radiochemical yield and purity of [¹⁸F]fMLFXYk(FB)k were 16% and >96%, respectively. The in vivo biodistribution study showed that [¹⁸F]fMLFXYk(FB)k uptake was higher in the bacterial infected region than in the non-infected region. We observed considerably higher infection-to-muscle ratio of 4.6 at 60?min after [¹⁸F]fMLFXYk(FB)k injection. Furthermore, small-animal PET imaging studies suggested that [¹⁸F]fMLFXYk(FB)k uptake in the bacterial infected region was clearly visualized 60?min after injection.     

Genomic sequence and virulence evaluation of MN184A‐like porcine reproductive and respiratory syndrome virus in Japan

In this study, a porcine reproductive and respiratory syndrome virus (PRRSV) that was isolated from a 9‐week‐old diseased pig on a farm in Japan with a high mortality rate during 2007–2008 was characterized. This unique isolate, designated as Jpn5‐37, did not have a high nucleotide identity in open reading frame 5 against any Japanese isolates. Among all available type 2 PRRSV complete genome sequences, Jpn5‐37 shared the highest nucleotide identity (93.6%) with virulent strain MN184A. The genomic characteristics of Jpn5‐37 were highly conserved with respect to the virulent MN184A, including a continuous eight amino acid deletion in the nonstructural protein 2 region. Moreover, virus distribution, viremia and the gross and microscopic characteristics of lesions were investigated in pigs 10 days post‐inoculation to elucidate the pathogenicity of the isolate. Intranasal inoculation was found to rapidly result in viremia and dissemination of the Jpn5‐37 isolate to several tissues in a similar manner to EDRD1; however, the amounts of Jpn5‐37 RNA in serum were significantly greater. Similarly, the quantities of Jpn5‐37 viral RNA in all organs tested tended to be higher than with EDRD1 infection. Mean rectal temperatures were significantly higher in the Jpn5‐37‐inoculated than in the control group at 4 and 6 days post infection (dpi) and in the EDRD1‐inoculated group at 6 and 8 dpi. These results suggest that the Jpn5‐37 strain replicates and is more efficiently distributed to the organs than is EDRD1 under the same conditions.     

Codon optimization effect on translational efficiency of DNA vaccine in mammalian cells: analysis of plasmid DNA encoding a CTL epitope derived from microorganisms.

Interspecific difference of codon usage is one of the major obstacles for effective induction of specific immune responses against bacteria and protozoa by DNA immunization. Using genes encoding major histocompatibility complex class I-restricted cytotoxic T-lymphocyte (CTL) epitopes, derived from an intracellular bacterium, Listeria monocytogenes and a mouse malaria parasite, Plasmodium yoelii, we report here that the codon optimization level of the genes is not precisely proportional to, but does correlate well with the translational efficiency in mammalian cells, which is concomitantly associated with the induction level of specific CTL response in the mouse. These results suggest that DNA immunization using the gene codon-optimized to mammals through the entire region is very effective.     

ApA Dinucleotide Periodicity in Prokaryote, Eukaryote, and Organelle Genomes

Computer analyses of various genome sequences revealed the existence of certain periodical patterns of adenine–adenine dinucleotides (ApA). For each genome sequence of 13 eubacteria, 3 archaebacteria, 10 eukaryotes, 60 mitochondria, and 9 chloroplasts, we counted frequencies of ApA dinucleotides at each downstream position within 50 bp from every ApA. We found that the complete genomes of all three archaebacteria have clear ApA periodicities of about 10 bps. On the other hand, all of the 13 eubacteria we analyzed were found to have an ApA periodicity of about 11 bp. Similar periodicities exist in the 10 eukaryotes, although higher organisms such as primates tend to have weaker periodic patterns. None of the mitochondria and chroloplasts we analyzed showed an evident periodic pattern. Received: 3 November 1998 / Accepted: 24 March 1999