Phytase,Phosphatase Activity and P-Nutrition of Soybean as Influenced by Inoculation of <Emphasis Type="Italic">Bacillus</Emphasis>

The efficiency of different Bacillus isolates on rhizosphere soil enzyme activities and P-nutrition of soybean was carried out under microcosm conditions. Significant increase in enzyme activities viz., fluorescein diacetate activity, phosphatase and phytase activity and consequent effects on P-nutrition were observed with the inoculation of Bacillus isolates over uninoculated control. Among the isolates, BD-3-1B, KHBD-6, BDKH-3, Bacillus amyloliquefacians, and Bacillus cereus were found to be promising. The phytic acid-P as a percentage of total P content in soybean seeds decreased with the inoculation of Bacillus isolates as compared to un-inoculated control. A decrease in phytic-P in soybean seeds not only results in better digestibility and increased feed efficiency. Pearson correlation studies revealed a significant positive association between acid, alkaline phosphatases, phytase activity on available P content in soil and P content in seeds with the inoculation of Bacillus isolates, indicating role of these enzymes in P mobilization and acquisition by soybean.     

A newly isolated Streptomyces sp. CS392 producing three antimicrobial compounds

With the aim of isolating new microbes capable of producing strong antimicrobial substances, strain CS392 was screened from 700 soil isolates preserved in our laboratory. The strain was related to genus Streptomyces based on various characteristics. Three highly active antimicrobial compounds, C1, C2 and C3, produced by the strain were purified by solvent extraction followed by silica gel column chromatography. These compounds were highly active against various Gram-positive resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Staphylococcus aureus (VRSA), and vancomycin-resistant Enterococcus (VRE). Among three, C3 was the most active against MRSA and VRSA with minimal inhibitory concentration (MIC) of 2 μg/ml while C2 and C3 had MIC values of 4 μg/ml for the strains. In case of Bacillus subtilis ATCC6633, C1 and C3 were more effective with MIC values of 0.5 μg/ml than C2 with MIC of 2 μg/ml. Those antibiotics were variably active (MIC of 4-32 μg/ml) against Micrococcus luteus ATCC 9341, Enterococcus faecalis ATCC 29212, Mycobacterium smegmatis ATCC 9341 and VRE.     

Dietary zinc reduces osteoclast resorption activities and increases markers of osteoblast differentiation,matrix maturation,and mineralization in the long bones of growing rats

The nutritional influence of zinc on markers of bone extracellular matrix resorption and mineralization was investigated in growing rats. Thirty male weanling rats were randomly assigned to consume AIN-93G based diets containing 2.5, 5, 7.5, 15 or 30 μg Zn/g diet for 24 days. Femur zinc increased substantially as zinc increased from 5 to 15 μg/g diet and modestly between 15 and 30 μg/g (P<.05). By morphological assessment, trabecular bone increased steadily as dietary zinc increased to 30 μg/g. Increasing dietary zinc tended to decrease Zip2 expression nonsignificantly and elevated the relative expression of metallothionen-I at 15 but not 30 μg Zn/g diet. Femur osteoclastic resorption potential, indicated by matrix metalloproteinases (MMP-2 and MMP-9) and carbonic anhydrase-2 activities decreased with increasing dietary zinc. In contrast to indicators of extracellular matrix resorption, femur tartrate-resistant acid and alkaline phosphatase activities increased fourfold as dietary zinc increased from 2.5 to 30 μg Zn/g. Likewise, 15 or 30 μg Zn/g diet resulted in maximum relative expression of osteocalcin, without influencing expression of core-binding factor α-1, collagen Type 1 alpha-1, or nuclear factor of activated T cells c1. In conclusion, increased trabecular bone with additional zinc suggests that previous requirement estimates of 15 μg Zn/g diet may not meet nutritional needs for optimal bone development. Overall, the up-regulation of extracellular matrix modeling indexes and concomitant decrease in resorption activities as dietary zinc increased from 2.5 to 30 μg/g provide evidence of one or more physiological roles for zinc in modulating the balance between bone formation and resorption.     

Assessing the Zinc solubilization ability of <Emphasis Type="Italic">Gluconacetobacter diazotrophicus</Emphasis> in maize rhizosphere using labelled <Superscript>65</Superscript>Zn compounds

Solubilization of insoluble zinc compounds like ZnCO₃ and ZnO by G. diazotrophicus was confirmed using radiotracers. The zinc compounds (ZnCO₃ and ZnO) were tagged with ⁶⁵Zn. ⁶⁵ZnCO₃ and ⁶⁵ZnO was effectively solubilized and the uptake of zn by the plants also more in G. diazotrophicus inoculated treatments compared to the uninoculated treatments. Three types of soils (Zn deficientsterile, Zn deficient-unsterile, and Zn sufficient-sterile) were used in experiment. Among the three soils, Zn deficient-unsterile soil registered maximum zinc solubilization compared to other two soils. This may be due to other soil microorganisms in unsterile soil. Application of ZnO with G. diazotrophicus showed better uptake of the nutrient.     

Microcosm study for revegetation of barren land with wild plants by some plant growth-promoting rhizobacteria

Growth promotion of wild plants by some plant growth-promoting rhizobacteria (PGPR) was examined in the microcosms composed of soils collected separately from a grass-covered site and a nongrass-covered site in a lakeside barren area at Lake Paro, Korea. After sowing the seeds of eight kinds of wild plants and inoculation of several strains of PGPR, the total bacterial number and microbial activity were measured during 5 months of study period, and the plant biomasses grown were compared at the end of the study. Acridine orange direct counts in the inoculated microcosms, 1.3-9.8 x 10(9) cells x g soil(-1) in the soil from the grass-covered area and 0.9-7.2 x 10(9) cells x g soil(-1) in the soil from the nongrass-covered site, were almost twice higher than those in the uninoculated microcosms. The number of Pseudomonas sp., well-known bacteria as PGPR, and the soil dehydrogenase activity were also higher in the inoculated soils than the uninoculated soils. The first germination of sowed seeds in the inoculated microcosm was 5 days earlier than the uninoculated microcosm. Average lengths of all plants grown during the study period were 26% and 29% longer in the inoculated microcosms starting with the grass-covered soil and the nongrass-covered soil, respectively, compared with those in the uninoculated microcosms. Dry weights of whole plants grown were 67-82% higher in the inoculated microcosms than the uninoculated microcosms. Microbial population and activity and growth promoting effect by PGPR were all higher in the soils collected from the grass-covered area than in the nongrass-covered area. The growth enhancement of wild plants seemed to occur by the activities of inoculated microorganisms, and this capability of PGPR may be utilized for rapid revegetation of some barren lands.     

Phosphate fertilization reduces zinc adsorption by calcareous soils

Summary Zinc adsorption isotherms were constructed for three calcereous soils which varied in carbonate contents, texture, and past history of phosphate fertilization. The equilibrium conditions were 25°C, 0.01 M CaCl₂ and 6 days.Higher phosphate fertilization of the soils reduced Zn adsorption. The effect of P was more in the soil with lower carbonate content which suggested that soil carbonates played a dominant role in the Zn adsorption characteristics of the soils.The adsorption data conformed to the Langmuir equation. Constants (k and b) calculated from the Langmuir isotherm showed that bonding energies (k) were inversely related to extractable P; i.e. higher Zn adsorption was associated with lower bonding energy. The Zn adsorption maxima (b) were higher for the soils with higher calcium carbonate equivalent.Adsorbed Zn was extracted with a single extraction of 0.005 M DTPA. The recovery was 91 percent for the Tandojam soil, 82 percent for the Tarnab soil, and 63 percent for the Kala shah Kaku soil, indicating that most of the adsorbed Zn is not irreversibly fixed by the soils and can be utilized by plant during growth.The results suggest that P-induced Zn deficiency could not be ascribed to precipitation of Zn as insoluble Zn-P compounds in soils. The increased Zn solubility with P fertilization is the evidence that P-Zn interaction does not reside in the growing medium external to plant.The work is part of Ph.D. thesis submitted to the University of Hawaii, Honolulu, U.S.A.     

Effects in chicks of arsenic,arginine, and zinc and their interaction on body weight,plasma uric acid,plasma urea,and kidney arginase activity

The interaction among arsenic, zinc, and arginine was studied in chicks using two fully crossed, three-way, two-by-two-by-two experiments. Arsenic at levels of 0 and 2 μg/g zinc at levels of 2.5 (zinc-deficient) and 25 (zinc-adequate) μg/g, and arginine at levels of 0 and 16 mg/g were supplemented to the diet. After 28 d in both experiments, growth was depressed in chicks fed diets either supplemented with arginine or deficient in zinc. Arsenic deprivation depressed growth of chicks fed diets containing the basal level of arginine and 25 μg supplemental Zn/g. Arsenic deprivation had little or no effect on growth of zinc-deprived chicks fed diets containing the basal level of arginine, or in zinc-deprived or zinc-adequate chicks fed supplemental arginine. Zinc-deficiency elevated urea in plasma and arginase activity in kidney. Those elevations, however, were more marked in arsenic-supplemented than in arsenic-deprived chicks. Also, plasma urea and kidney arginase activity were markedly elevated in chicks fed supplemental arginine; the elevations were more marked in zinc-deficient chicks. These findings support the concept that arsenic has a physiological role, associated with zinc, that can influence arginine metabolism in the chick.     

Effect of dsRNA-containing and dsRNA-free hypovirulent isolates of Fusarium oxysporum on severity of Fusarium seedling disease of soybean in naturally infested soil

In the sandy soils of eastern Virginia, soybean seedlings are colonized by hypovirulent and virulent isolates of Fusarium oxysporum and F. solani. Our objectives were to determine if prior inoculation of soybean seeds with hypovirulent F. oxysporum isolates reduced severity of seedling disease in naturally infested soil, and to determine if there was an association between the presence of dsRNA mycovirus and hypovirulence in isolates of F. oxysporum and F. solani from soybean plants. The presence of dsRNA was not associated with hypovirulence in F. oxysporum since some hypovirulent isolates contained dsRNA while other hypovirulent isolates did not. Furthermore, of six dsRNA-containing F. oxysporum isolates, three were hypovirulent and three were virulent. Four segments of dsRNA, with sizes of 4.0, 3.1, 2.7 and 2.2 kb were detected in extracts of all six F. oxysporum isolates. No hypovirulent or dsRNA-containing of F. solani isolates were found. Prior inoculation of cv. Essex soybean seeds with conidia of dsRNA-free hypovirulent F. oxysporum isolates significantly (P < 0.05) reduced disease severity on cotyledons and hypocotyls, and increased the rate of seedling emergence in field soil, compared to control plants. No significant (P > 0.05) differences were found between dsRNA-containing and dsRNA-free hypovirulent F. oxysporum isolates in their effects on reducing disease severity. Hypovirulent isolates that colonize soybean tissues may play a role in reducing Fusarium seedling disease of soybean in natural soils.     

有机物料对滨海盐渍土重金属根际效应的影响Ⅰ.土壤内源Zn形态分布

研究了排水条件下施用腐熟有机物料、种稻改良滨海盐渍土内源Ｚｎ形态分布．结果表明,单淹水使土中各形态Ｚｎ一定程度上向生物有效性较低的Ｚｎ形态转化,有效态Ｚｎ降低．土壤盐分量不同,明显影响无定形氧化铁结合态、紧结有机态以及硅酸盐矿物态Ｚｎ变化．种稻不施有机物料,根际交换态和硅酸盐矿物态Ｚｎ亏缺;碳酸盐结合态、氧化锰结合态和无定形氧化铁结合态Ｚｎ富集．根际Ｚｎ形态转化强度大于非根际,其有效态Ｚｎ量接近临界值并高于非根际．有机物料利于根际内外土壤中硅酸盐矿物态Ｚｎ的转化,低盐土壤根际更强烈．随有机物料用量增加,促使根际硅酸盐矿物态、碳酸盐结合态及氧化锰结合态Ｚｎ向交换态、紧结有机态和无定形氧化铁结合态Ｚｎ转化,低盐土壤较明显．     

Trace Metal Contents of Selected Seeds and Vegetables from Oil Producing Areas of Nigeria

The concentrations of accumulated trace metals in selected seeds and vegetables collected in the oil producing Rivers State of Nigeria were investigated. The values were compared with those of seeds and vegetables cultivated in Owerri, a less industrialized area in Nigeria. The lead (Pb) and cadmium (Cd) contents of the seeds obtained from Rivers State ranged between 0.10 and 0.23 μg/g dry weight, while those of the seeds cultivated in Owerri fell below the detection limit of 0.01 μg/g dry weight. The highest manganese (Mn) level (902 μg/g dry weight) was found in Irvingia garbonesis seeds cultivated in Rivers State. Similarly, the highest nickel (Ni) value (199 μg/g dry weight) was also obtained in I. garbonesis, however, in the seeds sampled in Owerri. The highest copper (Cu), zinc (Zn), and iron (Fe) levels (16.8, 5.27, and 26.2 μg/g dry weight, resp.) were detected in seeds collected in Rivers State. With the exception of Talinum triangulae, Ocinum gratissimum, and Piper guineese, with Pb levels of 0.09, 0.10, and 0.11 μg/g dry weight, respectively, the Pb and Cd levels in the vegetables grown in Owerri fell below the detection limit of 0.01 μg/g dry weight. The trace metal with the highest levels in all the vegetables studied was Mn, followed by Fe. The highest concentrations of Ni and Cu occurred in vegetables collected from Rivers State, while the highest level of Zn was observed in Piper guineese collected in Owerri, with a value of 21.4 μg/g dry weight. Although the trace metal concentrations of the seeds and vegetables collected in Rivers State tended to be higher than those of the seeds and vegetables grown in Owerri, the average levels of trace metals obtained in this study fell far below the WHO specifications for metals in foods.     

几种黑豆种子维生素E的优化提取及含量对比

以北方三省7种黑豆种子为原料,经过优化提取,对维生素E含量进行对比分析。结果显示:黑豆种子维生素E优化提取条件为;40mmol.L-1显色剂(α,α-联吡啶)、1mmol.L-1反应物(FeCl3)、6mmol.L-1中止反应物质(H3PO4),显色时间为6min;Ⅲ(襄垣)与Ⅳ(灵丘)维生素E含量较高,分别为95.7μg.g-1和70.2μg.g-1;Ⅰ(赤峰)与Ⅱ(齐齐哈尔)维生素E含量较少,分别为23.1μg.g-1和33.7μg.g-1。该优化提取方法简便、易于操作,且精确度高;山西省襄垣和灵丘两地黑豆VE含量较高。研究结果对该地黑豆产品深加工与利用有一定的指导作用。     

Induction of metallothionein by exposure to normobaric 100% oxygen atmosphere in rats with different zinc supply

The objective of this study was to determine the effects of an oxygen enriched environment on the induction of the metalloprotein metallothionein (MT) and its relation to zinc metabolism in rats supplied with different levels of dietary zinc. Male albino rats were fed purified diets based on maize starch, egg white, saccharose and soybean oil differing in the concentration of zinc (1; 20; 100; 500 mg Zn/kg diet). At a dietary zinc supply of 1 mg/kg, the rats developed a zinc deficiency indicated by visual and biochemical parameters. At the end of the 37-day feeding period, half of the rats were exposed to 100% oxygen for 12 h.

The oxygen treatment significantly reduced plasma zinc in the zinc supplemented rats and reduced it in tendency in the zinc deficient rats. The MT concentration was increased in the zinc supplemented groups in the liver, kidney and lung. The oxygen treatment elevated the metallothionein concentration in the two high zinc supplemented groups (100 and 500 mg Zn/kg diet) in the liver. The response of the zinc concentration in plasma and of hepatic metallothionein levels to oxygen exposure indicates a role of metallothionein in zinc distribution or interactions with other trace elements to support antioxidant capacity, rather than an impact on direct scavenging activity of free radicals.     

Detection and characterization of plasmid pJP4 transfer to indigenous soil bacteria

Prior to gene transfer experiments performed with nonsterile soil, plasmid pJP4 was introduced into a donor microorganism, Escherichia coli ATCC 15224, by plate mating with Ralstonia eutropha JMP134. Genes on this plasmid encode mercury resistance and partial 2, 4-dichlorophenoxyacetic acid (2,4-D) degradation. The E. coli donor lacks the chromosomal genes necessary for mineralization of 2,4-D, and this fact allows presumptive transconjugants obtained in gene transfer studies to be selected by plating on media containing 2,4-D as the carbon source. Use of this donor counterselection approach enabled detection of plasmid pJP4 transfer to indigenous populations in soils and under conditions where it had previously not been detected. In Madera Canyon soil, the sizes of the populations of presumptive indigenous transconjugants were 10(7) and 10(8) transconjugants g of dry soil(-1) for samples supplemented with 500 and 1,000 microg of 2,4-D g of dry soil(-1), respectively. Enterobacterial repetitive intergenic consensus PCR analysis of transconjugants resulted in diverse molecular fingerprints. Biolog analysis showed that all of the transconjugants were members of the genus Burkholderia or the genus Pseudomonas. No mercury-resistant, 2, 4-D-degrading microorganisms containing large plasmids or the tfdB gene were found in 2,4-D-amended uninoculated control microcosms. Thus, all of the 2,4-D-degrading isolates that contained a plasmid whose size was similar to the size of pJP4, contained the tfdB gene, and exhibited mercury resistance were considered transconjugants. In addition, slightly enhanced rates of 2,4-D degradation were observed at distinct times in soil that supported transconjugant populations compared to controls in which no gene transfer was detected.     

Effects of Different Calcium, Magnesium, and Zinc Concentrations Supplemented on Hepatopancreatic Cell Proliferation of Kuruma Prawn, Penaeus japonicus

The effects of different calcium (Ca(2+)), magnesium (Mg(2+)), and zinc (Zn(2+)) concentrations supplemented on hepatopancreatic cell proliferation of kuruma prawn, Penaeus japonicus was studied. The culture system consists of medium 199 (M 199) supplemented with 0.060 mol/L NaCl, 1.011 g/L glucose, 1,000 UI/ml penicillin, 1,000 μg/ml treptomycin, heat inactivated fetal calf serum (FCS) 20% for primary cell culture and 10% for subculture. The RNA/DNA ratio of the cell cultures was measured. The results show that the cell division of hepatopancreatic cells of P. japonicus was enhanced by the optimal concentration of inorganic salt (Ca(2+), 1.0 g/L; Mg(2+), 5.0 g/L; Zn(2+), 80 μg/L). The hepatopancreatic cell culture system and improved culture conditions described here will be very useful for in vitro experiments to study viruses responsible for infections in shrimp leading to tremendous economic losses.     

Zinc distribution and excretion in the leaves of the grey mangrove,Avicennia marina (Forsk.) Vierh

Mangroves are important as primary producers in estuarine food chains. Zinc is often a major anthropogenic contaminant in estuarine ecosystems and has potential ecotoxicological consequences for mangrove communities. Accumulation, distribution and excretion of zinc in the leaf tissue of the grey mangrove, Avicennia marina was studied using SEM X-ray microanalysis and Atomic Absorption Spectroscopy. The first leaves of A. marina grown in 500 μg Zn as ZnCl₂ per g of dry soil were found to accumulate 106.3±18.5 μg Zn per g dry tissue, significantly higher than control plants, after a 7-month period. Washings from first leaves contained significantly higher amounts of zinc (0.30±0.14 μg/cm² Zn) than control plants after 1 month, suggesting excretion of zinc from glandular trichomes. SEM X-ray microanalysis revealed salt crystals exuded from glandular tissue on the adaxial surface of first leaves to be composed of alkaline metals and zinc in zinc treated plants. SEM X-ray microanalysis of seedlings dosed with 4 g/l Zn as Zn Cl₂ revealed a decreasing Zn gradient from xylem tissue, through photosynthetic mesophyll, to hypodermal (water) tissue. A subsequent increase in Zn concentration was observed in glandular tissue. Cell wall Zn concentrations were consistently higher than intracellular Zn concentrations.     

Analysis of the abilities of endophytic bacteria associated with banana tree roots to promote plant growth

A total of 40 endophytic bacterial isolates obtained from banana tree roots were characterized for their biotechnological potential for promoting banana tree growth. All isolates had at least one positive feature. Twenty isolates were likely diazotrophs and formed pellicles in nitrogen-free culture medium, and 67% of these isolates belonged to the genus Bacillus sp. The isolates EB-04, EB-169, EB-64, and EB-144 had N fixation abilities as measured by the Kjeldahl method and by an acetylene reduction activity assay. Among the 40 isolates, 37.5% were capable of solubilizing inorganic phosphate and the isolates EB-47 and EB-64 showed the highest solubilization capacity. The isolate EB-53 (Lysinibacillus sp.) had a high solubilization index, whereas 73% of the isolates had low solubilization indices. The synthesis of indole-3-acetic acid (IAA) in the presence of L-tryptophan was detected in 40% of the isolates. The isolate EB-40 (Bacillus sp.) produced the highest amount of IAA (47.88 μg/ml) in medium supplemented with L-tryptophan and was able to synthesize IAA in the absence of L-tryptophan. The isolates EB-126 (Bacillus subtilis) and EB-47 (Bacillus sp.) were able to simultaneously fix nitrogen, solubilize phosphate and produce IAA in vitro. The results of this study demonstrated that the isolates analyzed here had diverse abilities and all have the potential to be used as growth-promoting microbial inoculants for banana trees.     

Effect of clay,organic matter and CaCO3 content on zinc adsorption by soils

Summary Zinc adsorption was studied in suspensions of six soils of different physicochemical characteristics in dilute ZnSO₄ solutions. At low concentrations, Zn²⁺ adsorption was described by the Langmuir adsorption equation. The calculated Langmuir adsorption maxima were related positively to clay and carbonate content and negatively with organic matter content of soils. Multiple regression analysis revealed that zinc adsorption maxima can be predicted with good precision from information in soil survey reports. When the added Zn²⁺ exceeded the adsorption maximum, the solid phase of zinc controlling its concentration in solution was either zinc hydroxide or carbonate so long as soil carbonates were present. The values of zinc potential also indicated that soils retain Zn²⁺ more strongly than Zn(OH)₂ or carbonate. Postgraduate student Professor of Soils. Professor of Soils.     

Impairment in reproductive development is a major factor limiting yield of black gram under zinc deficiency

Black gram [Vigna mungo (L.) Hepper] cv. IPU 94 plants grown in sand culture with deficient zinc (0.1 μM Zn) nutrition and those deprived of normal (1 μM) Zn supply at the initiation of flowering, showed decrease in dry matter production and especially seed yield. These plants showed a decrease in the size of anthers and stigmatic heads, pollen producing capacity of the anthers and stigmatic exudations. Zn deficiency caused structural alterations in exine and retarded germination of pollen grains and tube growth. The pollen extracts and stigmatic exudates of the Zn-deficient plants showed increase in activity of acid phosphatase isoforms and inhibition of esterase isoforms. Zn deficiency led to decrease in number of pods, seeds per pod and seed mass, altered seed coat topography and reduced seeds germinability. Low seed yield under Zn deficiency is attributed to a role of Zn in pollen function, as also in pollen-pistil interaction conducive to fertilization and development of seeds.     

A comparative study of element concentrations and binding in transgenic and non-transgenic soybean seeds

Transgenic and non-transgenic soybean seeds were compared in terms of total element concentrations, behavior of elements during sequential extraction fractionation and element bioaccessibility using an in vitro simulated gastrointestinal digestion. The analysis were carried out by ICP-sector field-MS or size-exclusion ICP-MS (25 elements in concentrations varying from ng g?1 to the % level). It seems that transgenic and non-transgenic soybean seeds exhibit statistically significant differences in concentrations of Cu, Fe and Sr, which are also reflected by element contents in water extracts and residues. Additionally, contributions of bioaccessible fractions of Cu, Fe and other elements (Mn, S, Zn) for transgenic soybean seeds appear to be larger than those found in non-transgenic soybean seeds.     

The Use of <Emphasis Type="Italic">Bradyrhizobium</Emphasis> to Enhance Growth and Yield of Soybean in Calcareous Soil in Uzbekistan

In this work the effect of inoculation with Bradyrhizobium japonicum S2492 on soybean (Glycine max (L) Merr) growth, nodulation and yield in nitrogen-deficient soil of Uzbekistan was studied. The field experiments were carried out in Tashkent Province of Uzbekistan in a randomized complete block design with four replicates of each treatment. The results revealed positive effects on growth, nodule number and yields of soybean after inoculation with B. japonicum S2492. The yield of soybean varieties was 48% higher for inoculated than for uninoculated plants. The effect of the inoculation was specific for variety but not for growth type. The protein and oil contents of seeds also increased after inoculation. It was concluded that B. japonicum S2492 can be considered as a biofertilizer for increasing the productivity of soybean in nitrogen-deficient soils in Uzbekistan.