Asthma visits to emergency rooms and soybean unloading in the harbors of Valencia and A Coruna, Spain.
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Soybean unloading in the harbor of Barcelona, Spain, has been associated with large increases in the numbers of asthma patients treated in emergency departments between 1981 and 1987. In this study, the association between asthma and soybean unloading in two other Spanish cities, Valencia and A Coruna, was assessed. Asthma admissions were retrospectively identified for the period 1993-1995, and harbor activities were investigated in each location. Two approaches were used to assess the association between asthma and soybean unloading: One used unusual asthma days (days with an unusually high number of emergency room asthma visits) as an effect measure, and the other estimated the relative increase in the daily number of emergency room visits by autoregressive Poisson regression, adjusted for meteorologic variables, seasonality, and influenza incidence. No association between unusual asthma days and soya unloading was observed in either Valencia or A Coruna, except for one particular dock in Valencia. When the association between unloaded products and the daily number of emergency asthma visits was studied, a statistically significant association was observed for unloading of soya husk (relative risk = 1.50, 95% confidence interval 1.16-1.94) and soybeans (relative risk = 1.31, 95% confidence interval 1.08-1.59) in A Coruna. In Valencia, a statistical association was found only for the unloading of soybeans at two particular docks. Although these findings support the notion that asthma outbreaks are not a common hidden condition in most harbors where soybeans are unloaded, the weak associations reported are likely to be causal. Therefore, appropriate control measures should be implemented to avoid soybean dust emissions, particularly in harbors with populations living in the vicinity. (+info)
Mutation in GDP-fucose synthesis genes of Sinorhizobium fredii alters Nod factors and significantly decreases competitiveness to nodulate soybeans.
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We mutagenized Sinorhizobium fredii HH103-1 with Tn5-B20 and screened about 2,000 colonies for increased beta-galactosidase activity in the presence of the flavonoid naringenin. One mutant, designated SVQ287, produces lipochitooligosaccharide Nod factors (LCOs) that differ from those of the parental strain. The nonreducing N-acetylglucosamine residues of all of the LCOs of mutant SVQ287 lack fucose and 2-O-methylfucose substituents. In addition, SVQ287 synthesizes an LCO with an unusually long, C20:1 fatty acyl side chain. The transposon insertion of mutant SVQ287 lies within a 1.1-kb HindIII fragment. This and an adjacent 2.4-kb HindIII fragment were sequenced. The sequence contains the 3' end of noeK, nodZ, and noeL (the gene interrupted by Tn5-B20), and the 5' end of nolK, all in the same orientation. Although each of these genes has a similarly oriented counterpart on the symbiosis plasmid of the broad-host-range Rhizobium sp. strain NGR234, there are significant differences in the noeK/nodZ intergenic region. Based on amino acid sequence homology, noeL encodes GDP-D-mannose dehydratase, an enzyme involved in the synthesis of GDP-L-fucose, and nolK encodes a NAD-dependent nucleotide sugar epimerase/dehydrogenase. We show that expression of the noeL gene is under the control of NodD1 in S. fredii and is most probably mediated by the nod box that precedes nodZ. Transposon insertion into neoL has two impacts on symbiosis with Williams soybean: nodulation rate is reduced slightly and competitiveness for nodulation is decreased significantly. Mutant SVQ287 retains its ability to form nitrogen-fixing nodules on other legumes, but final nodule number is attenuated on Cajanus cajan. (+info)
A novel 53-kDa nodulin of the symbiosome membrane of soybean nodules, controlled by Bradyrhizobium japonicum.
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A nodule-specific 53-kDa protein (GmNOD53b) of the symbiosome membrane from soybean was isolated and its LysC digestion products were microsequenced. cDNA clones of this novel nodulin, obtained from cDNA library screening with an RT-PCR (reverse-transcriptase polymerase chain reaction)-generated hybridization probe exhibited no homology to proteins identified so far. The expression of GmNOD53b coincides with the onset of nitrogen fixation. Therefore, it is a late nodulin. Among other changes, the GmNOD53b is significantly reduced in nodules infected with the Bradyrhizobium japonicum mutant 184 on the protein level as well as on the level of mRNA expression, compared with the wild-type infected nodules. The reduction of GmNOD53b mRNA is related to an inactivation of the sipF gene in B. japonicum 184, coding for a functionally active signal peptidase. (+info)
A multisubunit acetyl coenzyme A carboxylase from soybean.
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A multisubunit form of acetyl coenzyme A (CoA) carboxylase (ACCase) from soybean (Glycine max) was characterized. The enzyme catalyzes the formation of malonyl CoA from acetyl CoA, a rate-limiting step in fatty acid biosynthesis. The four known components that constitute plastid ACCase are biotin carboxylase (BC), biotin carboxyl carrier protein (BCCP), and the alpha- and beta-subunits of carboxyltransferase (alpha- and beta-CT). At least three different cDNAs were isolated from germinating soybean seeds that encode BC, two that encode BCCP, and four that encode alpha-CT. Whereas BC, BCCP, and alpha-CT are products of nuclear genes, the DNA that encodes soybean beta-CT is located in chloroplasts. Translation products from cDNAs for BC, BCCP, and alpha-CT were imported into isolated pea (Pisum sativum) chloroplasts and became integrated into ACCase. Edman microsequence analysis of the subunits after import permitted the identification of the amino-terminal sequence of the mature protein after removal of the transit sequences. Antibodies specific for each of the chloroplast ACCase subunits were generated against products from the cDNAs expressed in bacteria. The antibodies permitted components of ACCase to be followed during fractionation of the chloroplast stroma. Even in the presence of 0.5 M KCl, a complex that contained BC plus BCCP emerged from Sephacryl 400 with an apparent molecular mass greater than about 800 kD. A second complex, which contained alpha- and beta-CT, was also recovered from the column, and it had an apparent molecular mass of greater than about 600 kD. By mixing the two complexes together at appropriate ratios, ACCase enzymatic activity was restored. Even higher ACCase activities were recovered by mixing complexes from pea and soybean. The results demonstrate that the active form of ACCase can be reassembled and that it could form a high-molecular-mass complex. (+info)
Further studies of the role of cyclic beta-glucans in symbiosis. An NdvC mutant of Bradyrhizobium japonicum synthesizes cyclodecakis-(1-->3)-beta-glucosyl.
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The cyclic beta-(1-->3),beta-(1-->6)-D-glucan synthesis locus of Bradyrhizobium japonicum is composed of at least two genes, ndvB and ndvC. Mutation in either gene affects glucan synthesis, as well as the ability of the bacterium to establish a successful symbiotic interaction with the legume host soybean (Glycine max). B. japonicum strain AB-14 (ndvB::Tn5) does not synthesize beta-glucans, and strain AB-1 (ndvC::Tn5) synthesizes a cyclic beta-glucan lacking beta-(1-->6)-glycosidic bonds. We determined that the structure of the glucan synthesized by strain AB-1 is cyclodecakis-(1-->3)-beta-D-glucosyl, a cyclic beta-(1-->3)-linked decasaccharide in which one of the residues is substituted in the 6 position with beta-laminaribiose. Cyclodecakis-(1-->3)-beta-D-glucosyl did not suppress the fungal beta-glucan-induced plant defense response in soybean cotyledons and had much lower affinity for the putative membrane receptor protein than cyclic beta-(1-->3),beta-(1-->6)-glucans produced by wild-type B. japonicum. This is consistent with the hypothesis presented previously that the wild-type cyclic beta-glucans may function as suppressors of a host defense response. (+info)
The involvement of cysteine proteases and protease inhibitor genes in the regulation of programmed cell death in plants.
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Programmed cell death (PCD) is a process by which cells in many organisms die. The basic morphological and biochemical features of PCD are conserved between the animal and plant kingdoms. Cysteine proteases have emerged as key enzymes in the regulation of animal PCD. Here, we show that in soybean cells, PCD-activating oxidative stress induced a set of cysteine proteases. The activation of one or more of the cysteine proteases was instrumental in the PCD of soybean cells. Inhibition of the cysteine proteases by ectopic expression of cystatin, an endogenous cysteine protease inhibitor gene, inhibited induced cysteine protease activity and blocked PCD triggered either by an avirulent strain of Pseudomonas syringae pv glycinea or directly by oxidative stress. Similar expression of serine protease inhibitors was ineffective. A glutathione S-transferase-cystatin fusion protein was used to purify and characterize the induced proteases. Taken together, our results suggest that plant PCD can be regulated by activity poised between the cysteine proteases and the cysteine protease inhibitors. We also propose a new role for proteinase inhibitor genes as modulators of PCD in plants. (+info)
Dietary soybeans intake and bone mineral density among 995 middle-aged women in Yokohama.
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To investigate relationship of dietary factors, especially source of calcium intake, to bone mineral density (BMD) among Japanese middle-aged women, a total of 995 healthy women age of 40 to 49 (mean +/- SD, 45 +/- 3), who lives in Yokohama-city, were recruited through convenience sampling by the municipal information paper and health announcement at each 18 public health center in 18 wards for the three-day course on prevention of osteoporosis from October 1996 to March 1998. The BMD of the 2nd metacarpal bone was measured using Computed X-ray Densitometry (CXD) method, by a trained radiologist. Dietary intake of calcium was assessed by self-reporting food frequency questionnaire on calcium dietary sources such as milk, dairy products, small fish, vegetables, and soybeans and carefully checked by trained dietician. An independent gradient of non-adjusted and adjusted BMD for age and weekly calcium intake, through soybeans intake frequency (p = 0.03) was noted. This study suggest soybeans, through possible beneficial effects of vitamin-K, soyprotein, and isoflavonoid, may affect BMD of middle aged women. (+info)
Degradation of two protein sources at three solids retention times in continuous culture.
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Effects of solids retention times (SRT) of 10, 20, and 30 h on protein degradation and microbial metabolism were studied in continuous cultures of ruminal contents. Liquid dilution rate was constant across all retention times at .12 h(-1) (8.3 h mean retention time). Two semipurified diets that contained either soybean meal (SBM) or alfalfa hay (ALFH) as the sole nitrogen source were provided in amounts that decreased as SRT was increased. Digestion coefficients for DM, NDF, and ADF increased with increasing SRT. Digestion coefficients for nonstructural carbohydrates were higher in the SBM diet than in the ALFH diet but were not affected by SRT. Protein degradation in the ALFH diet averaged 51% and was unaffected by retention time. In the SBM diet, digestion of protein was 77, 78, and 96% at 10-, 20-, and 30-h retention times, respectively. Microbial efficiency decreased with increasing SRT and was greater for the SBM than for the ALFH diet. Efficiencies ranged from 30.6 to 35.7 and 20.8 to 29.2 g of N/kg of digested DM for the SBM and ALFH diets, respectively, as SRT decreased from 30 to 10 h. The diaminopimelic acid content of the microbes increased as SRT increased, indicating that changes in microbial species occurred owing to passage rates. From these results, we concluded that the digestibility decreases associated with increased ruminal turnover rates may be less for nonstructural carbohydrates and protein than for the fiber fractions. (+info)