Quantification of genetically modified soybean by quenching probe polymerase chain reaction

Quenching probe (QProbe) polymerase chain reaction (PCR) is a simple and cost-effective real-time PCR assay in comparison with other real-time PCR assays such as the TaqMan assay. We used QProbe-PCR to quantify genetically modified (GM) soybean (Roundup Ready soybean). We designed event-specific QProbes for Le1 (soy endogenous gene) and RRS (recombinant gene), and we quantified certified reference materials containing 0.1, 0.5, 1, 2, and 5% GM soybean. The TaqMan assay was also applied to the same samples, and the results were compared. The accuracy of QProbe-PCR was similar to that of TaqMan assay. When GM soybean content was 0.5% or more, the relative standard deviations of QProbe-PCR were less than 20%. QProbe-PCR is sensitive enough to monitor labeling systems and has acceptable levels of accuracy and precision.     

Changes in nitrogen transformation in forest soil representing the climate gradient of the Japanese archipelago

Net nitrogen transformation was investigated under different climate conditions by soil transplantation and in situ incubation of forest surface soils using the resin-core method. Selected conditions were considered to reflect those of the natural climate gradient in the Japanese archipelago. Study sites were established in natural forests in northern Hokkaido (Uryu), northern Kanto (Kusaki), central Kinki (Kamigamo), and southern Kyushu (Takakuma), representing the northernmost to the southernmost island regions of Japan. Field experiments comparing soils incubated at “native” and “transplanted” sites were conducted from June 2008 to May 2009. Net production, accumulation, and leaching of soil ammonium (NH₄ ⁺) and nitrate (NO₃ ⁻) were measured at each of the sites during the growing season (June–October), the dormant season (November–May), and throughout the year. Net nitrate production was highest in Kusaki soil, especially during the growing season, whereas net ammonium production was highest in Uryu soil, the coldest site, especially during the dormant season. Net nitrate production increased significantly in soils transplanted to a warmer climate during the growing season. However, net ammonium production increased in soils transplanted to colder climates during the dormant season. These findings indicate that, with the exception of the infertile soil samples from Kamigamo, the range of natural climates in Japan has a significant effect on nitrogen availability in surface soil. In addition, the original characteristics of the nitrogen cycle of the surface soil from each native site were retained, even when marked changes in soil temperature (approximately 8°C) occurred after transplantation.     

The forming process of the peculiar Mn-mottling in the polder

In the subsurface horizons of some paddy fields at the Kojima polder, Okayama Prefecture, the authors noticed a peculiar Mn-mottling, which had not been found in the common paddy fields. Several paddy soils in varying stages of maturity were carefuIIy surveyed at the Kojima polder. The soils were tentatively named OK4, OK7, OKS, and OK9. The ages of the fields after reclamation were about 10, 100, 150, and 250 years, respectively. Undisturbed samples were collected from 3 soils (OK4, OK7, and OKS) for microscopic observation and chemical analysis.     

Nitrogen fixation in paddy soils

The 4 long-term experimental plots (Umbric haplaquept) with different fertilizer treatment at Cent. Agric. Exp. Sta. in Konosu City, Saitama Prefecture, were used for the sites of investigation. The 4 plots were NF (applied with no fertilizer), IF (applied with inorganic fertilizers), GM (applied with green manure and CaCO₂), and OM (applied with manure and inorganic fertilizers). Flooded water, floating weed, upper (0-2cm) and lower (2-10cm) parts of Apg horizon and rhizosphere were collected from each plot before flooding, during flooding, and after drainage. These samples were analyzed for N₂-fixing activity by acetylene reduction method, pH, Eh, and contents of Fe²⁺, NH₄ ⁺, chlorophyll-type compounds, and water-soluble carbohydrates.

The N₂-fixing activity of all samples showed almost the same pattern of change with time: very low before flooding, rapidly increased after flooding, the maximum value at the maximum tillering stage of rice plant, declined afterwards and reached a very low value after drainage.

Rough estimation of the “N₂-fixing capacity” of each part of the paddy field revealed that the most important site of the N₂ fixation was the reduced Apg horizon, that the importance of flooded water and/or the oxidized layer in the N₂ fixation was rather low except in infertile soil, and that the role of rhizosphere in the N₂ fixation could not be neglected also in Japan.

Reduced condition and content of easily decomposable organic substances were judged to be main factors which control the N₂-fixing activity in the flooded soil on the basis of correlations between the Nt-fixing activity and several analytical data of the paddy soils.     

A new method for determining free iron in paddy soils

For pedological or edaphological study, it is very important to find a suitable method for determining free iron in soils. The removal of free iron also facilitates the identification and determination of minerals present in soils and clays by X-ray and thermal analysis and microscopic observation. Up to the presnt time many methods have been proposed for the removal or the determination of free iron in soils and clays. With some exceptions these methods are all based on the principle that the free iron compounds existing mainly as ferric iron in soils are reduced to ferrous iron and extracted with suitable reagents. A short historical review is as follows.     

Comparison of several methods for determining free iron in soils

In the previous paper (1), for determining free iron in paddy soils the writers proposed a new method in which free iron was removed by reduction with sodium hydrosulfite in disodium ethylendiamine tetraacetate solution. As described in that paper, many methods have been proposed up to the present time. In this paper the writers are to compare their method with some of those methods, especially with both methods using sodium hydrosulfite and dilute hydrochloric acid and using hydrogen sulfide and dilute hydrochloric acid. The latter method has generally been employed for free iron determination of paddy soils in Japan.     

Formation of Methyl Mercaptan in Paddy Soils (II)

In the previous paper₁₎, the authors proposed a method for determining methyl mercaptan formed in paddy soils. In this method, methyl mercaptan was expelled by nitrogen gas from Paddy soils, and was introduced into 4% mercuric CYanide solution after separation from hydrogen sulfide by hydrous calcium chloride and lead acetate (solid). The methyl mercaptan caught by mercuric cyanide solution was measured by colorimetric method using dimethyl-p-phenylenediamine and ferric chloride solutions. And then, the analysis of several field soils was conducted by using this method.     

Prevalence of zoonotic Bartonella species among rodents and shrews in Thailand

We investigated the prevalence of Bartonella species in 10 rodent and one shrew species in Thailand. From February 2008 to May 2010, a total of 375 small animals were captured in 9 provinces in Thailand. Bartonella strains were isolated from 57 rodents (54 from Rattus species and 3 from Bandicota indica) and one shrew (Suncus murinus) in 7 of the 9 provinces, and identified to the species level. Sequence analysis of the citrate synthase and RNA polymerase β subunit genes identified the 58 isolates from each Bartonella-positive animal as B. tribocorum in 27 (46.6%) animals, B. rattimassiliensis in 17 (29.3%) animals, B. elizabethae in 10 (17.2%) animals and B. queenslandensis in 4 (6.9%) animals. R. norvegicus, R. rattus, and Suncus murinus carried B. elizabethae, which causes endocarditis in humans. The prevalence of Bartonella bacteremic animals by province was 42.9% of the animals collected in Phang Nga, 26.8% in Chiang Rai, 20.4% in Sa Kaeo, 16.7% in Nakhon Si Thammarat, 12.0% in Surat Thani, 9.1% in Mae Hong Son and Loei Provinces.     

Evaluation of feeding value of forage soybean silage as a substitute for wheat bran in sheep

Twelve sheep were used in a 3 × 3 Latin square design to evaluate the effect of substituting wheat bran with forage soybean silage in the diet on apparent digestibility and nitrogen balance. Forage soybean (Glycine max (L.) Merrill) was cultivated in a no‐till, no‐herbicide cropping system with Italian ryegrass (Lolium multiflorum Lam.) as a living mulch. Forage soybean and Italian ryegrass were wilted and ensiled in round bales without additives, respectively. The experimental diets were based on corn silage supplemented with protein sources (tow silages or wheat bran). The crude protein and the acid detergent insoluble protein contents of forage soybean silage were the highest among the protein sources. The apparent digestibility of crude protein and the nitrogen balance did not significantly differ among the diets. In addition, the phytoestrogen content of forage soybean silage was below the level at which animal reproductive performance would be negatively affected. These results suggest that forage soybean silage has comparable feeding value to wheat bran, and can be given at an inclusion level of 17% (dry matter basis) as an alternative protein source to wheat bran without adverse effects on digestion or nitrogen balance in sheep fed a corn silage‐based diet.