Fine structure and 18S rDNA phylogeny of a marine araphid pennate diatom Plagiostriata goreensis gen. et sp. nov. (Bacillariophyta)

A marine araphid pennate diatom Plagiostriata goreensis is described from the sand grains of Goree Island, Dakar, Republic of Senegal, based on observations of fine structure of its frustule. The most striking feature of the species is its striation, which is angled at approximately 60° across the robust sternum. The other defining features of the species are its one highly reduced rimoportula and apical pores located at both ends of the valve margin. In the 18S rDNA phylogeny, the species appears as a member of a ‘small‐celled clade’ of araphid pennate diatoms that consist of Nanofrustulum, Opephora and Staurosira. The results of the phylogenetic analyses suggest that the distinct characters of the diatom; namely, oblique striae and apical pores, may have been acquired independently. However, it remains unclear whether the rimoportula of P. goreensis is a reduced state or P. goreensis acquired its morphologically curious rimoportula independently after the loss of an ancient rimoportula at the root of the small‐celled clade.     

Development of mouse models for analysis of human virus infections

Viruses usually exhibit strict species‐specificity as a result of co‐evolution with the host. Thus, in mouse models, a great barrier exists for analysis of infections with human‐tropic viruses. Mouse models are unlikely to faithfully reproduce the human immune response to viruses or viral compounds and it is difficult to evaluate human therapeutic efficacy with antiviral reagents in mouse models. Humans and mice essentially have different immune systems, which makes it difficult to extrapolate mouse results to humans. In addition, apart from immunological reasons, viruses causing human diseases do not always infect mice because of species tropism. One way to determine tropism would be a virus receptor that is expressed on affected cells. The development of gene‐disrupted mice and Tg mice, which express human receptor genes, enables us to analyze several viral infections in mice. Mice are, indeed, susceptible to human viruses when artificially infected in receptor‐supplemented mice. Although the mouse cells less efficiently permit viral replication than do human cells, the models for analysis of human viruses have been established in vivo as well as in vitro, and explain viral pathogenesis in the mouse systems. In most systems, however, nucleic acid sensors and type I interferon suppress viral propagation to block the appearance of infectious manifestation. We herein review recent insight into in vivo antiviral responses induced in mouse infection models for typical human viruses.     

Studies on the ɛ-Lysine Acylase

?-Lysine acylase of Achromobacter pestifer EA was purified by fractionations with ammonium sulfate and acetone, and by vertical zone electrophoresis. As a result, this bacterial ?-lysine acylase was obtained as an electrophoretically homogeneous protein, specific activity of which is the highest among ?-lysine acylases ever reported.     

A cDNA from grapevine (Vitis vinifera L.), which shows homology to AGAMOUS and SHATTERPROOF,is not only expressed in flowers but also throughout berry development

An AGAMOUS/SHATTERPROOF homologue (Vvmads1) was isolated from grapevine by differential display between berry and leaf mRNA. The predicted protein sequence of the full-length clone shows a high degree of homology to PLENA (77% identity) and to SHP1 and SHP2 (75% and 74% identity respectively), and is grouped with AGAMOUS/PLENA homologues when the conserved MADS and K domains are compared. Vvmads1 is expressed only in the later stages of flower development and throughout berry development, although expression is reduced after ripening commenced. When Vvmads1 was over-expressed in tobacco, the resulting plants display altered morphologies in the outer two floral whorls. In the most extreme cases, the inner whorls were surrounded by a carpelloid structure created by the modified sepals. Within these sepals were petals which had been split into sections and which were attached at the base of the flower by structures with the appearance of filaments. The results of this study suggest that Vvmads1 has a regulatory role in flower development before fertilisation and a role in fruit development after fertilisation.     

Effect of chemical modifications on freeze denaturation of lactate dehydrogenase

Lactate dehydrogenase (LDH) was chemically ethyl-acetimidated (EA-), dimethyladipimidated (DMA-), carbamylated, acetylated, acetoacetylated, or succinylated in order to alter the ionic charges on the epsilon-amino group of lysine residues. Acetylation, acetoacetylation, and succinylation, which change the positive charge at the lysine side chains to a negative one, inactivated the enzymic activity, but the rest of the modifications exerted no such inactivating effects. The active modified enzymes were subjected to freeze denaturation study, using the enzymic activity as an indication of the degree of the denaturation. The active enzymes were diluted with deionized water and stored in a freezer (-23 degrees C) for 1-3 days. Enzymic activity was assayed immediately after thawing. All the modified enzymes retained their activity even after the 3-day frozen storage, while the control or native enzyme lost its activity within 1 day of storage. Furthermore, the modified LDHs freeze-stored in 0.2 M monosodium glutamate (MSG) or 0.2 M lysine-hydrochloride (Lys-HCl) retained their activity. The cryoprotective effects exerted by the modifications and by 0.2 M MSG seemed to be synergistic, whereas those exerted by the modifications and by 0.2 M Lys-HCl did not. The mechanisms of cryoprotection and freeze denaturation are discussed in relationship with the cryoprotective effect exerted by already known cryoprotectants, such as sucrose or dimethyl sulfoxide.     

Facile determination of DNA-binding nuclear factor-kappaB by chemiluminescence detection

A simple, rapid, and sensitive method for the assay of a sequence-specific DNA-binding protein, nuclear factor-kappaB (NF-kappaB), has been developed by using a DNA-detectable chemiluminogenic reagent and a centrifugal filter that distinguishes different molecular sizes. After the formation of a complex between NF-kappaB and DNA, the unbound DNA is separated from the complex by the centrifugal filter. The amount of the bound NF-kappaB is estimated by chemiluminescence detection of the bound DNA. This detection is performed within 2 min at room temperature by the use of a chemiluminogenic reagent, 3',4',5'-trimethoxyphenylglyoxal, which selectively recognizes guanine moiety in oligonucleotides or DNAs. This method does not require any labeled probes or antibodies and can determine a concentration as low as 5 nM of DNA-binding NF-kappaB. The sensitivity is nearly the same as that of other methods such as gel shift assay using fluorescence-labeled probes and enzyme-linked immunosorbent assay. Therefore, the current method provides a convenient tool for surveying various DNA-binding proteins.