Spatial and temporal flowering patterns of the monocarpic dwarf bamboo Sasa veitchii var. hirsuta

In order to clarify spatial and temporal patterns in the flowering process of S. veitchii var. hirsuta, the authors investigated the flowering of the species at a regional level in a mountainous area of Kyoto City, and at population/individual culm levels at experimental forest stations within the same municipal region. S. veitchii var. hirsuta flowered in several separate areas spanning ranges between several and more than 10?km north?Csouth and east?Cwest from 2004 to 2007. Sporadic flowering occurred the year before mass flowering. In the mass-flowering year, 98% of the culms in an S. veitchii var. hirsuta population flowered, and the other 2% or so flowered in the years before and after mass flowering. These results show a spatiotemporal synchronous flowering pattern (with most culms of populations gregariously flowering in a year over a large area) and an asynchronous flowering pattern (with a small percentage of the culms of populations flowering before and after the mass-flowering year) for S. veitchii var. hirsuta. It was also clarified that the year and scale of mass flowering differ by area, and that mass flowering occurs in individual areas in successive years. The survey performed at the individual culm level revealed that the mean numbers of open florets and attached seeds per culm showed two peaks from April to July, suggesting that S. veitchii var. hirsuta flowering events occur twice a year.     

Accumulation pattern of arachin and its subunits in maturation of groundnut seeds

The accumulation pattern of arachin and its subunits in growinggroundnuts was investigated. Soluble proteins were extractedfrom the kernels at twelve different stages of maturation (4–16weeks after pegging). Fractionation showed arachin, conarachinII, 5S and 2S protein components with sucrose gradient centrifugation.Ten weeks after pegging, only 35% of the maximum amount of arachinhad accumulated, whereas conarachin II was 85%, the 5S component89%, and the 2S component 76%. Arachin, however, increased rapidlyin the later stage of maturation. No change in the subunit ratioin arachin during seed growth was observed on the patterns ofsodium dodecyl sulfate-gel electrophoresis and gel isoelectricfocusing in the presence of urea. The ratio of the arachin subunitscontained in urea-extractable fraction of the kernels was constantthroughout seed development and was consistent with the subunitratio in arachin. On the other hand, the arachin subunits inthe free forms, if any, accounted for less than 1% of the associatedarachin subunits. Probably, the arachin subunits synthesizedin equimoles are associated into arachin without individualdeposition and are accumulated as arachin associates in growingseeds. (Received July 17, 1980; )     

Prophage excision switches the primary ribosome rescue pathway and rescue-associated gene regulations in Escherichia coli

Escherichia coli has multiple pathways to release nonproductive ribosome complexes stalled at the 3′ end of nonstop mRNA: tmRNA (SsrA RNA)-mediated trans-translation and stop codon-independent termination by ArfA/RF2 or ArfB (YaeJ). The arfA mRNA lacks a stop codon and its expression is repressed by trans-translation. Therefore, ArfA is considered to complement the ribosome rescue activity of trans-translation, but the physiological situations in which ArfA is expressed have not been elucidated. Here, we found that the excision of CP4-57 prophage adjacent to E. coli ssrA leads to the inactivation of tmRNA and switches the primary rescue pathway from trans-translation to ArfA/RF2. This “rescue-switching” rearranges not only the proteome landscape in E. coli but also the phenotype such as motility. Furthermore, among the proteins with significantly increased abundance in the ArfA⁺ cells, we found ZntR, whose mRNA is transcribed together as the upstream part of nonstop arfA mRNA. Repression of ZntR and reconstituted model genes depends on the translation of the downstream nonstop ORFs that trigger the trans-translation-coupled exonucleolytic degradation by polynucleotide phosphorylase (PNPase). Namely, our studies provide a novel example of trans-translation-dependent regulation and re-define the physiological roles of prophage excision.     

Smoking enhances the expression of angiotensin-converting enzyme 2 involved in the efficiency of severe acute respiratory syndrome coronavirus 2 infection

Smoking is one of the risk factors most closely related to the severity of coronavirus disease 2019 (COVID-19). However, the relationship between smoking history and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infectivity is unknown. In this study, we evaluated the ACE2 expression level in the lungs of current smokers, ex-smokers, and nonsmokers. The ACE2 expression level of ex-smokers who smoked cigarettes until recently (cessation period shorter than 6 months) was higher than that of nonsmokers and ex-smokers with a long history of nonsmoking (cessation period longer than 6 months). We also showed that the efficiency of SARS-CoV-2 infection was enhanced in a manner dependent on the angiotensin-converting enzyme 2 (ACE2) expression level. Using RNA-seq analysis on the lungs of smokers, we identified that the expression of inflammatory signaling genes was correlated with ACE2 expression. Notably, with increasing duration of smoking cessation among ex-smokers, not only ACE2 expression level but also the expression levels of inflammatory signaling genes decreased. These results indicated that smoking enhances the expression levels of ACE2 and inflammatory signaling genes. Our data suggest that the efficiency of SARS-CoV-2 infection is enhanced by smoking-mediated upregulation of ACE2 expression level.     

Transduction Profile of the Marmoset Central Nervous System Using Adeno-Associated Virus Serotype 9 Vectors

The common marmoset is a small New World primate that has attracted remarkable attention as a potential experimental animal link between rodents and humans. Adeno-associated virus (AAV) vector-mediated expression of a disease-causing gene or a potential therapeutic gene in the brain may allow the construction of a marmoset model of a brain disorder or an exploration of the possibility of gene therapy. To gain more insights into AAV vector-mediated transduction profiles in the marmoset central nervous system (CNS), we delivered AAV serotype 9 (AAV9) vectors expressing GFP to the cisterna magna or the cerebellar cortex. Intracisternally injected AAV9 vectors expanded in the CNS according to the cerebrospinal fluid (CSF) flow, by retrograde transport through neuronal axons or via intermediary transcytosis, resulting in diffuse and global transduction within the CNS. In contrast, cerebellar parenchymal injection intensely transduced a more limited area, including the cerebellar cortex and cerebellar afferents, such as neurons of the pontine nuclei, vestibular nucleus and inferior olivary nucleus. In the spinal cord, both administration routes resulted in labeling of the dorsal column and spinocerebellar tracts, presumably by retrograde transport from the medulla oblongata and cerebellum, respectively. Motor neurons and dorsal root ganglia were also transduced, possibly by diffusion of the vector down the subarachnoid space along the cord. Thus, these two administration routes led to distinct transduction patterns in the marmoset CNS, which could be utilized to generate different disease animal models and to deliver therapeutic genes for the treatment of diseases affecting distinct brain areas.     

Primary cilia-dependent lipid raft/caveolin dynamics regulate adipogenesis

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Analysis of Core Region from Egg White Lysozyme Forming Amyloid Fibrils

Some of the lysozyme mutants in humans cause systemic amyloidosis. Hen egg white lysozyme (HEWL) has been well studied as a model protein of amyloid fibrils formation. We previously identified an amyloid core region consisting of nine amino acids (designated as the K peptide), which is present at 54-62 in HEWL. The K peptide, with tryptophan at its C- terminus, has the ability of self-aggregation. In the present work we focused on its structural properties in relation to the formation of fibrils. The K peptide alone formed definite fibrils having β-sheet structures by incubation of 7 days under acidic conditions at 37°C. A substantial number of fibrils were generated under this pH condition and incubation period. Deletion and substitution of tryptophan in the K peptide resulted in no formation of fibrils. Tryptophan 62 in lysozyme was suggested to be especially crucial to forming amyloid fibrils. We also show that amyloid fibrils formation of the K peptide requires not only tryptophan 62 but also a certain length containing hydrophobic amino acids. A core region is involved in the significant formation of amyloid fibrils of lysozyme.