Development of damage function of acidification for terrestrial ecosystems based on the effect of aluminum toxicity on net primary production

Background  Acidification is one of the important impact categories for life cycle impact assessment. Although its characterization has progressed during this decade through the employment of midpoint approaches, only limited studies of endpoint approaches have been performed. Objective. This study aimed at developing damage function of acidification for terrestrial ecosystems in Japan. Damage function expresses a quantitative relationship between the inventory and endpoint damage. Methods  The geographical boundary was limited in Japan both for emission and impact. In this study, sulfur dioxide (SO₂), nitrogen monoxide (NO), nitrogen dioxide (NO₂) (NO and NO₂ collectively mean NO_x), hydrogen chloride (HC1), and ammonia (NH₃) were considered as major causative substances of acidification. Net primary production (NPP) of existing vegetation was adopted as an impact indicator of terrestrial ecosystems. The aluminum toxicity was adopted as the major factor of effect on terrestrial ecosystems due to acidification. The leachate concentration of monomeric inorganic aluminum ions was selected to express the plant toxicity of aluminum. Results and Discussion  The results of damage function gave utilizable factors both for a midpoint approach and an endpoint approach; Atmospheric Deposition Factor (ADF) and Damage Factor (DF) applicable to the former and the latter, respectively. The ADF indicates an increase of H⁺ deposition per unit area to an additional emission of causative sustance. The additional emission corresponds to some alternatives in industry, not the baseline emission. The DF indicates the total NPP damage in all of Japan due to the additional emission of causative substances. The derived NPP damage is on the order of one millionth of the NPP itself. HC1 and NH3 showed larger ADFs and DFs than that of SO₂ and NO_x. The reason was ascribed to the relatively large source-receptor relationships (SRR) of HC1 and NH₃. However, since the method applied to determine the SRR of HC1 and NH₃ has larger uncertainties than that of SO₂ and NO_x, attention is needed to handle the difference. Conclusion  The damage function easily defines the concrete NPP damage due to an additional emission. The impact indica tor, NPP, also has an advantage in its mass unit that is directly summable through the entire impact categories. Expansion of endpoints, such as in aquatic ecosystems, material degradation, human health, and biodiversity aspects of terrestrial ecosystems, is an important subject for future work. Further, uncertain analyses for major parameters will provide helpful information on the reliability of damage function.     

Role of follicular dendritic cells in the early HIV-1 infection: in vitro model without specific antibody

About 90% of HIV-1 RNA in the lymph nodes is reported to localize in follicular dendritic cellsnetwork (FDC-NW) as early as several days after infection and as much as that in the late stage. But the mechanism remains to be fully understood. To elucidate the role of follicular dendritic cells (FDC) in the early stage of HIV-1 infection, FDC-like cell strains (FDCLC) were established and they were characterized in the co-culture system with T cells for their effect on HIV-1 trapping and replication in p24 immunoassay, immunohistochemistry as well as confocal and electronmicroscopy. Established FDCLC were positive for CNA-42, S-100alpha and intercellular desmosome-like junctions. L-SIGN and DC-SIGN were also detected in FDCLC. Alu-HIV-1 PCR analysis showed no HIV-1 integration in FDCLC. FDCLC trapped HIV-1 and transferred them to uninfected MOLT-4 T cells (MOLT-4) efficiently in the absence of specific antibody. FDCLC also accelerated HIV-1 replication in HIV-1-pre-exposed MOLT-4. These unique FDCLC effects were explained, at least partly, by the fact that FDCLC up-regulated CD4 expression in MOLT-4 and helped T cells escape from apoptosis in the co-culture. These data suggest that FDC/FDCLC engage not only in trapping but also in active expansion of HIV-1 in the absence of specific antibody.     

Prp5 bridges U1 and U2 snRNPs and enables stable U2 snRNP association with intron RNA

Communication between U1 and U2 snRNPs is critical during pre-spliceosome assembly; yet, direct connections have not been observed. To investigate this assembly step, we focused on Prp5, an RNA-dependent ATPase of the DExD/H family. We identified homologs of Saccharomyces cerevisiae Prp5 in humans (hPrp5) and Schizosaccharomyces pombe (SpPrp5), and investigated their interactions and function. Depletion and reconstitution of SpPrp5 from extracts demonstrate that ATP binding and hydrolysis by Prp5 are required for pre-spliceosome complex A formation. hPrp5 and SpPrp5 are each physically associated with both U1 and U2 snRNPs; Prp5 contains distinct U1- and U2-interacting domains that are required for pre-spliceosome assembly; and, we observe a Prp5-associated U1/U2 complex in S. pombe. Together, these data are consistent with Prp5 being a bridge between U1 and U2 snRNPs at the time of pre-spliceosome formation.     

New analogue of arenastatin A, a potent cytotoxic spongean depsipeptide, with anti-tumor activity

Two analogues possessing steric hindered substituents on C-15 of arenastatin A (1), a potent cytotoxic spongean depsipeptide, were synthesized and shown to enhance stability in mouse serum. Notably, 15-tert-butylanalogue (6) with higher cytotoxicity exhibited in vivo anti-tumor activity through iv administration different from 1. Additionally, conformation analysis among the two analogues and arenastatin A (1) indicated that the torsion angle from C-14 to C-20 is a conclusive factor for the potent cytotoxicity of 1.     

Synthesis of anilino-monoindolylmaleimides as potent and selective PKCbeta inhibitors

We report herein synthesis of PKCbeta-selective inhibitors possessing the novel pharmacophore of anilino-monoindolylmaleimide. Several compounds of this series exhibited IC50's as low as 50 nM against human PKCbeta2. One of the most potent compounds, 6l, inhibited PKCbeta1 and PKCbeta2 with IC50 of 21 and 5 nM, respectively, and exhibited selectivity of more than 60-fold in favor of PKCbeta2 relative to other PKC isozymes (PKCalpha, PKCgamma, and PKCepsilon).     

Cold-shock induced high-yield protein production in Escherichia coli

Overexpression of proteins in Escherichia coli at low temperature improves their solubility and stability. Here, we apply the unique features of the cspA gene to develop a series of expression vectors, termed pCold vectors, that drive the high expression of cloned genes upon induction by cold-shock. Several proteins were produced with very high yields, including E. coli EnvZ ATP-binding domain (EnvZ-B) and Xenopus laevis calmodulin (CaM). The pCold vector system can also be used to selectively enrich target proteins with isotopes to study their properties in cell lysates using NMR spectroscopy. We have cloned 38 genes from a range of prokaryotic and eukaryotic organisms into both pCold and pET14 (ref. 3) systems, and found that pCold vectors are highly complementary to the widely used pET vectors.     

Immune responses to Puumala virus infection and the pathogenesis of nephropathia epidemica

Puumala virus, causative agent of a mild form of hemorrhagic fever with renal syndrome, also known as nephropathia epidemica, induces long-lasting humoral and cellular immunity in patients. The virus itself is not cytopathic, and the immune responses to the virus may be involved in teh pathogenesis of the disease.     

Genetic divergence between and within two color morphotypes of <Emphasis Type="Italic">Parapercis sexfasciata</Emphasis> (Perciformes: Pinguipedidae) from Tosa Bay,southern Japan

The anterior half of the mitochondrial DNA control region (mtCR) sequence (ca. 400 base pairs) was compared between two color morphotypes (A, B) of Parapercis sexfasciata from Tosa Bay, southern Japan, using 16 and 21 specimens, respectively. Intramorphotypic mtCR divergences were only 0.0–0.5% and 1.0–2.5% for morphotypes A and B, respectively. In contrast, intermorphotypic mtCR divergence was much greater, 12.7–14.0%. Furthermore, phylogenetic analysis using a neighbor-joining algorithm, with P. multifasciata as an outgroup, showed that each morphotype was reciprocally monophyletic. These results and the distinct coloration and overlapping distribution indicate that the two color morphotypes of P. sexfasciata represent two distinct species. Mismatch distribution analysis suggested that both morphotypes had undergone population expansion; however, estimates of initial population sizes and mutational timescales suggested that morphotype B comprises historically larger and older populations than morphotype A.     

A new hypothesis for species coexistence: male–male repulsion promotes coexistence of competing species

We propose a new hypothesis for species coexistence by considering behavioral interactions between individuals. The hypothesis states that repulsive behavior between conspecific males (male–male repulsion) creates space for competing species, which promotes their coexistence. This hypothesis can explain the coexistence of two competing species even when their ecological niches completely overlap in spatially homogeneous environments. In addition, the mechanisms underlying such behavior might play a role in enabling the coexistence of two species immediately after speciation, with little or no niche differentiation, as in the case of cichlid fish communities, for example. Although there is limited evidence supporting this hypothesis, it can nevertheless explain the occurrence of species coexistence and biodiversity, which cannot be explained by previous theories.