Identification of a specific isoform of tomato lipoxygenase (TomloxC) involved in the generation of fatty acid-derived flavor compounds

There are at least five lipoxygenases (TomloxA, TomloxB, TomloxC, TomloxD, and TomloxE) present in tomato (Lycopersicon esculentum Mill.) fruit, but their role in generation of fruit flavor volatiles has been unclear. To assess the physiological role of TomloxC in the generation of volatile C6 aldehyde and alcohol flavor compounds, we produced transgenic tomato plants with greatly reduced TomloxC using sense and antisense constructs under control of the cauliflower mosaic virus 35S promoter. The expression level of the TomloxC mRNA in some transgenic plants was selectively reduced by gene silencing or antisense inhibition to between 1% and 5% of the wild-type controls, but the expression levels of mRNAs for the four other isoforms were unaffected. The specific depletion of TomloxC in transgenic tomatoes led to a marked reduction in the levels of known flavor volatiles, including hexanal, hexenal, and hexenol, to as little as 1.5% of those of wild-type controls following maceration of ripening fruit. Addition of linoleic or linolenic acid to fruit homogenates significantly increased the levels of flavor volatiles, but the increase with the TomloxC-depleted transgenic fruit extracts was much lower than with the wild-type control. Confocal imaging of tobacco (Nicotiana tabacum) leaf cells expressing a TomloxC-GFP fusion confirmed a chloroplast localization of the protein. Together, these results suggest that TomloxC is a chloroplast-targeted lipoxygenase isoform that can use both linoleic and linolenic acids as substrates to generate volatile C6 flavor compounds. The roles of the other lipoxygenase isoforms are discussed.     

Prospective analysis of the outcome of subpectoral breast augmentation: sensory changes, muscle function, and body image

This study is a prospective analysis of the outcome of subpectoral breast augmentation. Forty-seven patients undergoing breast augmentation were studied. They were assessed for pectoralis muscle function, breast sensation, and body image before and after subpectoral breast augmentation with saline implants. The patients were evaluated as follows: Pectoralis function was determined by measuring maximal voluntary isometric force. Sensation was evaluated by two means: vibration and pressure. The patient's body image was assessed using the Multidimensional Body-Self Relations Questionnaire. Results indicated a significant change in breast sensation at 3 months postoperatively but not at 6 months. Pectoralis muscle function did not significantly change during the study period. Body image was significantly improved at both postoperative measuring periods. The authors conclude that breast augmentation results in improved body image with negligible effect on muscle or nerve function.     

Effect of recent changes in atomic bomb survivor dosimetry on cancer mortality risk estimates

The Radiation Effects Research Foundation has recently implemented a new dosimetry system, DS02, to replace the previous system, DS86. This paper assesses the effect of the change on risk estimates for radiation-related solid cancer and leukemia mortality. The changes in dose estimates were smaller than many had anticipated, with the primary systematic change being an increase of about 10% in gamma-ray estimates for both cities. In particular, an anticipated large increase of the neutron component in Hiroshima for low-dose survivors did not materialize. However, DS02 improves on DS86 in many details, including the specifics of the radiation released by the bombs and the effects of shielding by structures and terrain. The data used here extend the last reported follow-up for solid cancers by 3 years, with a total of 10,085 deaths, and extends the follow-up for leukemia by 10 years, with a total of 296 deaths. For both solid cancer and leukemia, estimated age-time patterns and sex difference are virtually unchanged by the dosimetry revision. The estimates of solid-cancer radiation risk per sievert and the curvilinear dose response for leukemia are both decreased by about 8% by the dosimetry revision, due to the increase in the gamma-ray dose estimates. The apparent shape of the dose response is virtually unchanged by the dosimetry revision, but for solid cancers, the additional 3 years of follow-up has some effect. In particular, there is for the first time a statistically significant upward curvature for solid cancer on the restricted dose range 0-2 Sv. However, the low-dose slope of a linear-quadratic fit to that dose range should probably not be relied on for risk estimation, since that is substantially smaller than the linear slopes on ranges 0-1 Sv, 0-0.5 Sv, and 0- 0.25 Sv. Although it was anticipated that the new dosimetry system might reduce some apparent dose overestimates for Nagasaki factory workers, this did not materialize, and factory workers have significantly lower risk estimates. Whether or not one makes allowance for this, there is no statistically significant city difference in the estimated cancer risk.     

RIC-8 is required for GPR-1/2-dependent Galpha function during asymmetric division of C. elegans embryos

Heterotrimeric G proteins are crucial for asymmetric cell division, but the mechanisms of signal activation remain poorly understood. Here, we establish that the evolutionarily conserved protein RIC-8 is required for proper asymmetric division of one-cell stage C. elegans embryos. Spindle severing experiments demonstrate that RIC-8 is required for generation of substantial pulling forces on astral microtubules. RIC-8 physically interacts with GOA-1 and GPA-16, two Galpha subunits that act in a partially redundant manner in one-cell stage embryos. RIC-8 preferentially binds to GDP bound GOA-1 and is a guanine nucleotide exchange factor (GEF) for GOA-1. Our analysis suggests that RIC-8 acts before the GoLoco protein GPR-1/2 in the sequence of events leading to Galpha activation. Furthermore, coimmunoprecipitation and in vivo epistasis demonstrate that inactivation of the Gbeta subunit GPB-1 alleviates the need for RIC-8 in one-cell stage embryos. Our findings suggest a mechanism in which RIC-8 favors generation of Galpha free from Gbetagamma and enables GPR-1/2 to mediate asymmetric cell division.     

Detection of mustelid herpesvirus-1 infected European badgers (Meles meles) in the British Isles

The aim of this study was to assess the frequency of mustelid herpesvirus-1 (MusHV-1) infection in free-ranging badgers (Meles meles) in the British Isles. A polymerase chain reaction assay was developed that detected MusHV-1 DNA in 95% (18/19) and 100% (10/10) of anticoagulant-treated blood samples collected from free-ranging badgers sampled in the southwest of England and the Republic of Ireland, respectively. An indirect immunoassay was also developed to detect MusHV-1-specific immunoglobulin-G in serum samples. Using an arbitrary cutoff of twice the optical density obtained with a virus-negative preparation, 32.7% (36/110) of sera sampled from badgers were positive. The conclusion drawn from these data is that infection with MusHV-1 is common among free-ranging badgers in the British Isles.     

Evaluation of a Clostridium perfringens predictive model, developed under isothermal conditions in broth, to predict growth in ground beef during cooling

Proper temperature control is essential in minimizing Clostridium perfringens germination, growth, and toxin production. The U.S. Department of Agriculture (USDA) Food Safety and Inspection Service (FSIS) offers two options for the cooling of meat products: follow a standard time-temperature schedule or validate that alternative cooling regimens result in no more than a 1-log(10) CFU/g increase of C. perfringens and no growth of Clostridium botulinum. A mathematical model developed by Juneja et al. (Food Microbiol. 16:335-349, 1999) may be helpful in determining if the C. perfringens performance standard has been achieved, but this model has not been extensively validated. The objective of this study was to validate the Juneja 1999 model in ground beef under a variety of changing temperature and temperature abuse situations. The Juneja 1999 model consistently underpredicted growth of C. perfringens during exponential cooling of ground beef. The model also underpredicted growth of C. perfringens in ground beef cooled at two different rates. The results presented here show generally good agreement with published data on the growth of C. perfringens in similar products. The model error may be due to faster-than-expected exponential growth rates in ground beef during cooling or an error in the mathematical formulation of the model.     

Construction of replicative and integrative plasmids for setting up the in vivo expression technology in Helicobacter pylori

Some pathogenic factors of Helicobacter pylori, a bacterium involved in peptic ulcer and gastric cancer, have already been identified using either global or particular approach, but there are still some orphan genes and unidentified pathogenic factors. One of the methods used successfully for the identification of virulence genes of many pathogens is the in vivo expression technology. We describe here the construction and sequences of three different plasmids, one integrative and two replicatives, for the identification of virulence genes by using in vivo expression technology in H. pylori, and of potential use in other bacteria such as Campylobacter spp. Moreover, the use of the green fluorescent protein could allow to classify the genes according to the strength of their expression and to identify those which are repressed upon interaction with gastric mucosa.     

Mitochondrial Respiratory Chain Complex Patterns from Acanthamoeba castellanii and Lycopersicon esculentum: Comparative Analysis by BN-PAGE and Evidence of Protein–Protein Interaction Between Alternative Oxidase and Complex III

We have previously shown that a kinetic interplay exists between the cytochrome pathway and the alternative oxidase in mitochondria from amoeba Acanthamoeba castellanii . Native interaction analyses using blue native gel electrophoresis coupled to denaturating electrophoresis and immunodetection have indicated associations between alternative oxidase and oxidative phosphorylation complexes in both amoeba and tomato mitochondria. These associations are dependent on the expression level of alternative oxidase according to the physiological state in both organisms. Alternative oxidase associates broadly with large complexes of the respiratory chain when it is expressed in large amount, i.e., in ripe tomato and exponentially growing amoeba. On the contrary, alternative oxidase interacts specifically with complex III even if expression of the oxidase is low, i.e., in green tomato and stationary phase amoeba. This specific interaction represents a higher level of regulation driven by protein-protein interactions leading to a direct kinetic interplay between the cytochrome pathway and alternative oxidase in both plant and amoeba mitochondria.     

A role for chromogranin A (4-16), a vasostatin-derived peptide, on human colonic motility. An in vitro study

The hypothesis that CgA-derived peptides may be involved in mechanisms modulating motility was tested. Human colonic smooth muscles were studied using an organ bath technique. Acetic acid (AA) effects were characterized on spontaneous mechanical activities (SMA) and on responses to transmural nerve stimulation (NS). AA induced a significant decrease in tone and abolished SMA; this effect was insensitive to either TTX or L-NAME/apamin. The AA-induced inhibitory effects were significantly reduced in the presence of CgA4-16. This effect was insensitive to TTX or L-NAME/apamin. Furthermore, AA-induced effects were blocked in the presence of BAYK8644 and CgA4-16 together. The inhibitory effect of nifedipine was delayed in the presence of CgA4-16. NS induced a triphasic response. Only the excitatory components were reduced in the presence of AA. This effect was dose-related and remained unchanged in the presence of CgA4-16 alone, but was blocked in the presence of simultaneous administration of CgA4-16 and L-NAME/apamin. AA application induced inhibition of human colon motility in vitro. This effect may be mediated through an action on L-type calcium channels. CgA4-16 may display a protective role, which prevents the inhibition of motility due to AA to occur, by acting on both smooth muscle and afferent terminals.