DNA strand scissions by hydroxamic acids in the presence of Cu(II) ion under aerobic conditions.

Carbazolyloxyacetohydroxamic acid (1), 9,9'-decamethylene-bis-carbazolyloxyacetohydroxamic acid (2), benzohydroxamic acid (3), and acetohydroxamic acid (4) without reducing agent under aerobic conditions induced DNA strand scissions with increasing activities in the order of 4 > 3 > 2 > 1. The inhibition experiments indicated that hydrogen peroxide and superoxide participated in the reactions, but hydroxyl radical or singlet oxygen did not.     

Potential stocks of reef fish-based ecosystem services in the Kuroshio Current region: Their relationship with latitude and biodiversity

The latitudinal decline of species richness is a general spatial pattern of biodiversity, and it applies to marine species as well. Based on a latitudinal gradient of marine species richness, potential stocks of marine ecosystem services are expected to be higher in lower latitudes through increment in biodiversity. However, little is known about the relationships of the marine ecosystem services with latitude and biodiversity. We estimated the latitudinal patterns and relationships with the biodiversity of potential stocks of three major reef fish-based ecosystem services (fisheries production, aquarium fish production, and recreational diving) at ten coral habitats from tropical to temperate zones in the Kuroshio Current region (8°37′N–33°24′N) using field survey data and information from relevant websites and administrative statistics. We found a latitudinal declin from south to north in potential stocks of aquarium fish production and diving in this region, whereas the peaks of fisheries production were found around both tropical and sub-tropical zones. Our results also showed strong positive effects of biodiversity on potential stocks of the three ecosystem services, highlighting the importance of conserving diverse fish species to sustain multiple services at high levels. Broad spatial patterns of the reef fish-based ecosystem services are useful as baselines for future evaluation of their changes. As the effects of climate change on reef fishes are predicted to vary among different latitude zones, our estimates of the ecosystem services infer specific management and economic actions for the respective zones against climate change.     

Control of the growth of Alicyclobacillus acidoterrestris in industrialized orange juice using rosemary essential oil and nisin

The use of rosemary essential oil (RO) and its combination with nisin (RO+N) in preventing the multiplication of Alicyclobacillus acidoterrestris in orange juice was evaluated. The minimum inhibitory and bactericidal concentrations (MIC and MBC) for RO were both 125 μg ml⁻¹ while RO+N displayed a synergistic effect. The use of RO and RO+N at concentrations of 1, 4 and 8× MIC in orange juice for 96 h was evaluated in terms of their sporicidal effectiveness. With regard to the action against A. acidoterrestris spores, RO at 8× MIC was sporostatic, whereas RO+N at 1× MIC was sporicidal. Morphological changes in the structure of the micro-organism after treatment were also observed by microscopy. Furthermore, flow cytometric analysis showed that most cells were damaged or killed after treatment. In general, the antioxidant activity after addition of RO+N decreased with time. The results demonstrate that using the combination of RO and nisin can prevent the A. acidoterrestris growth in orange juice.     

Mitophagy in plants

Mitochondria play a central role in primary metabolism in plants as well as in heterotrophic eukaryotes. Plants must control the quality and number of mitochondria in response to a changing environment, across cell types and developmental stages. Mitophagy is defined as the degradation of mitochondria by autophagy, an evolutionarily conserved system for the removal and recycling of intracellular components. Recent studies have highlighted the importance of mitophagy in plant stress responses. This review article summarizes our current knowledge of plant mitophagy and discusses the underlying mechanisms. In plants, chloroplasts cooperate with mitochondria for energy production, and autophagy also targets chloroplasts through a process known as chlorophagy. Advances in plant autophagy studies now allow a comparative analysis of the autophagic turnover of mitochondria and chloroplasts, via the selective degradation of their soluble proteins, fragments, or entire organelles.     

Changes in Targeting Efficiencies of Proteins to Plant Microbodies Caused by Amino Acid Substitutions in the Carboxy-terminal Tripeptide

It has been demonstrated that the carboxyl terminus of microbodyenzymes functions as a targeting signal to microbodies in higherplants. We have examined an ability of 24 carboxy-terminal aminoacid sequences to facilitate the transport of a cytosolic passengerprotein, ß-glucuroni-dase, into microbodies in greencotyledonary cells of trans-genic Arabidopsis. Immunoelectronmicroscopic analysis revealed that carboxy-terminal tripeptidesequences of the form [C/A/S/P]-[K/R]-[I/L/M] function as amicrobody-targeting signal, although tripeptides with prolineat the first amino acid position and isoleucine at the carboxylterminus show weak targeting efficiencies. All known micro-bodyenzymes that are synthesized in a form similar in size to themature molecule, except catalase, contain one of these tripeptidesequences at their carboxyl terminus. (Received April 14, 1997; Accepted April 8, 1997)     

Interaction between lipopolysaccharide and intracellular serine protease zymogen, factor C, from horseshoe crab (Tachypleus tridentatus) hemocytes

The interaction between lipopolysaccharide (LPS) and an LPS-sensitive serine protease zymogen, factor C, purified from horseshoe crab (Tachypleus tridentatus) hemocytes, was investigated to elucidate the LPS-mediated activation of factor C. The rate of activation of the zymogen factor C was highly dependent on the concentration of LPS and on temperature, and the curve of amount of LPS versus activation showed saturation at 37 degrees C. Moreover, a high-molecular-mass complex formed between factor C and LPS was found in a gel-filtration experiment on a Sepharose 4B column. This complex formation was also confirmed by double diffusion analysis on agarose plates. Triton X-100, which destroys LPS micelles, strongly inhibited the LPS-mediated activation of factor C but not activated factor C. These results indicate that the binding of factor C with LPS is required for its activation and that only LPS-associated factor C generates the active factor C. On the other hand, the LPS-mediated activation of factor C was strongly inhibited by the S-alkylated heavy chain derived from factor C. In contrast, the S-alkylated factor C-light chain did not show any inhibitory effect on the activation of factor C, suggesting that the heavy chain located in the NH2-terminal portion of factor C contains an LPS-binding region.     

Application of a new slot comb to electrophoretic analysis.

In the present experiment, a new slot comb was designed in order to form a wide and sloped sample well on the stacking gel of electrophoresis. Using this slot comb, a gradient of the reagent layer of interest can be easily formed transversely on the gel that is perpendicular to the direction of electrophoresis. Thus, the protein sample overlaid on the agent migrates across the gradient layer during electrophoresis to produce a continuous electrophoretic band reflecting the interaction between the protein and reagent. This new slot comb (tentatively called slope comb) was applied to the following two experiments. In the first experiment, in combination with this comb and a reducing agent, 2-mercaptoethanol, the reducing steps of cross-linked axonemal proteins with o-iodosobenzoic acid (OIBA) were analyzed electrophoretically, enabling visualization of the reducing pattern of each axonemal protein in a single experiment. The results obtained indicate that alpha and beta tubulins are cross-linked differently by OIBA. In the second experiment, the formation of the Ca2+ gradient layer using this slope comb could electrophoretically differentiate the Ca2+ sensitivity of three Ca(2+)-binding proteins.