辐照杀菌对核桃粉品质的影响

研究了60Co γ辐照杀菌对核桃粉主要营养成分变化及感官品质的影响。结果表明：剂量为2.0～8.0kGy时,辐照对核桃粉中的总糖、粗蛋白和粗脂肪含量无显著影响;辐照后的粗纤维含量有一定的增加,但不显著;辐照对核桃粉中的月桂酸和肉豆蔻酸含量基本没有影响,对棕榈酸、棕榈油酸、硬脂酸、亚油酸、花生酸和亚麻酸含量有一定的影响,但不显著;辐照后核桃粉中的油酸含量随辐照剂量的上升而显著增加,剂量达到8.0kGy时,油酸含量增加了4.3%。8.0kGy以下辐照对核桃粉色泽、气味、口感无明显改变。可以得出结论低于8.0kGy的辐照不会对核桃粉的营养品质和感官品质有不良影响。     

and Its Expression in Pichia pastoris

利用RT-PCR技术扩增出草鱼(Ctenopharyngodon idellus)的leptin基因，将leptin基因克隆至真核表达载体pPIC9K，电穿孔转化GS115菌株, 经G418筛选和甲醇诱导后，对表达产物进行SDS-PAGE琼脂糖凝胶电泳和Western blot分析。结果表明，草鱼leptin基因cDNA序列由438个核苷酸组成，编码146个氨基酸组成的多肽（GenBank登陆号AY551335），与鲤鱼(Cyprinus carpio)leptin基因相比， 核苷酸和氨基酸的同源性为99%； 与人、猪和鼠相比，核苷酸同源性分别为84%、86%和95%, 氯基酸的同源性分别为84%、82%和96%；与河豚(Takifugu rubripes)相比，氨基酸具有较大的差异，仅有9％的同源性，表明leptin在物种的进化上具有一定的差异；实现了草鱼leptin基因在毕赤酵母(Pichia pastoris)中的表达，表达蛋白的分子量约为16 kD， Western blot 分析表明，表达产物具有一定的免疫学活性。     

Characterization of intergeneric hybrids of <Emphasis Type="Italic">Erianthus rockii</Emphasis> and <Emphasis Type="Italic">Saccharum</Emphasis> using molecular markers

Erianthus rockii, a wild relative of sugarcane, is drought and cold tolerant, and both are potentially important agronomic traits to the sugarcane industry worldwide. As such it is of interest as a source of parental germplasm to sugarcane breeders and is currently being used in sugarcane introgression programs in both China and Australia. To date morphological characters have been used to verify the putative hybrids produced. Two crosses were generated between two different Saccharum species and two E. rockii accessions. Over 400 AFLP markers were used to identify the intergeneric hybrid progeny as well as determine hybrid diversity. Both crosses generated hybrids but efficiency levels were very different and are probably related to the different Saccharum parent used in each cross. Cross 1 was between a Saccharum officinarum and E. rockii and generated 100% hybrid progeny. Cross 2, however, was between a sugarcane hybrid (S. officinarum × Saccharum spontaneum) and E. rockii and only 10% of the progeny were intergeneric hybrids. Inheritance of markers in the progeny was analysed and for both crosses there were equal numbers of markers from both parents indicating n + n transmission of chromosomes. This is the first verification of E. rockii hybrids with molecular markers. It may now be possible to exploit genes of value from E. rockii in sugarcane breeding programs.     

Production of Intergeneric Hybrids Between <Emphasis Type="Italic">Sinapis alba</Emphasis> and <Emphasis Type="Italic">Brassica carinata</Emphasis>

Reciprocal crosses were made between Brassica carinata and its related species Sinapis alba. Pollen germination studies indicated the presence post-fertilization barriers in both ways. Sequential ovary–ovule culture helped to realize the intergeneric hybrids from the cross S. alba × B. carinata. The F₁ obtained was confirmed as a hybrid based on morphology, cytology and isozyme studies. The hybrid was backcrossed to its male parent and obtained BC₁ seeds, which were used to raise BC₁ generation. The BC₁ generation plants were further backcrossed to B. carinata in order to develop alloplasmic lines.     

in Gastrointestinal Tracts of Chicken

以30 d Arbor Acre (AA)肉鸡为模型，采集胃肠道样品，采用相对定量RT-PCR方法研究了生长抑素(SS ) mRNA在鸡胃肠道分布的组织特异性。结果表明，腺胃SS mRNA的表达量高于所有肠段，差异极显著 (P＜0.01)；十二指肠和空肠SS mRNA的表达丰度相似，二者均显著高于回肠(P＜0.05)。定性研究显示，肌胃和结直肠均有SS mRNA表达，但其表达量显著低于腺胃、十二指肠、空肠和回肠。SS mRNA在主要的消化(腺胃)、吸收(十二指肠和空肠前段)器官的高丰度表达，提示SS对营养物质的消化吸收具有重要的调控作用。     

Purification and isotopic signatures (<Emphasis Type="Italic">δ</Emphasis><Superscript>13</Superscript>C, <Emphasis Type="Italic">δ</Emphasis><Superscript>15</Superscript>N, Δ<Superscript>14</Superscript>C) of soil extracellular DNA

The aim of this work was to obtain pure extracellular DNA molecules so as to estimate their longevity in soil by an isotope-based approach. Extracellular DNA molecules were extracted from all horizons of a forest soil and purified by the procedure of Davis (Purification and precipitation of genomic DNA with phenol–chloroform and ethanol. In: Davis LG, Dibner MD, Battey JF (eds) Basic methods in molecular biology. Appleton & Lange, Norwalk, 16–22, 1986) without (DNA1) or with (DNA2) a successive treatment with binding resins followed by elution. The two differently purified DNA samples were compared for their A₂₆₀/A₂₈₀ ratio, polymerase chain reaction (PCR) amplification and natural abundance of stable (¹³C and ¹⁵N) and radioactive (¹⁴C) isotopes. The purity index and the PCR amplification did not differentiate the efficiency of the two purification procedures. The isotopic signature of DNA was more sensitive and was strongly affected by the purification procedures. The isotopic measurements showed that the major contaminant of extracellular DNA1 was the soil organic matter (SOM), even if it is not possible to exclude that the similar δ ¹³C, δ ¹⁵N and Δ¹⁴C values of DNA and SOM could be due to the use of SOM-deriving C and N atoms for the microbial synthesis of DNA. For extracellular DNA2, extremely low values of Δ¹⁴C were obtained, and this was ascribed to the presence of fossil fuel-derived substances used during the purification, although in amounts not revealed by gas chromatography-mass spectrometry analysis. The fact that it is not possible to obtain contaminant-free DNA molecules and the potential use of soil native organic compounds during the microbial synthesis of DNA make it not achievable to estimate the age of soil extracellular DNA by radiocarbon dating.     

Effect of CO<Subscript>2</Subscript> on nitrification and immobilization of NH<Subscript>4</Subscript><Superscript>+</Superscript>-N

A laboratory incubation experiment was conducted to demonstrate that reduced availability of CO₂ may be an important factor limiting nitrification. Soil samples amended with wheat straw (0%, 0.1% and 0.2%) and (¹⁵NH₄)₂SO₄ (200 mg N kg^–1 soil, 2.213 atom% ¹⁵N excess) were incubated at 30±2°C for 20 days with or without the arrangement for trapping CO₂ resulting from the decomposition of organic matter. Nitrification (as determined by the disappearance of NH₄⁺ and accumulation of NO₃^–) was found to be highly sensitive to available CO₂ decreasing significantly when CO₂ was trapped in alkali solution and increasing substantially when the amount of CO₂ in the soil atmosphere increased due to the decomposition of added wheat straw. The co-efficient of correlation between NH₄⁺-N and NO₃^–-N content of soil was highly significant (r =0.99). During incubation, 0.1–78% of the applied NH₄⁺ was recovered as NO₃^– at different incubation intervals. Amendment of soil with wheat straw significantly increased NH₄⁺ immobilization. From 1.6% to 4.5% of the applied N was unaccounted for and was due to N losses. The results of the study suggest that decreased availability of CO₂ will limit the process of nitrification during soil incubations involving trapping of CO₂ (in closed vessels) or its removal from the stream of air passing over the incubated soil (in open-ended systems).     

Response of CH<Subscript>4</Subscript> oxidation and methanotrophic diversity to NH<Subscript>4</Subscript><Superscript>+</Superscript> and CH<Subscript>4</Subscript> mixing ratios

Methane oxidising activity and community structure of 11, specifically targeted, methanotrophic species have been examined in an arable soil. Soils were sampled from three different field plots, receiving no fertilisation (C), compost (G) and mineral fertiliser (M), respectively. Incubation experiments were carried out with and without pre-incubation at elevated CH₄ mixing ratios (100 ml CH₄ l⁻¹) and with and without ammonium (100 mg N kg⁻¹) pre-incubation. Four months after fertilisation, plots C, G and M did not show significant differences in physicochemical properties and CH₄ oxidising activity. The total number of methanotrophs (determined as the sum the 11 specifically targeted methanotrophs) in the fresh soils was 17.0×10⁶, 13.7×10⁶ and 15.5×10⁶ cells g⁻¹ for treatment C, G and M, respectively. This corresponded to 0.11 to 0.32% of the total bacterial number. The CH₄ oxidising activity increased 10⁵-fold (20–26 mg CH₄ g⁻¹ h⁻¹), the total number of methanotrophs doubled (28–76×10⁶ cells g⁻¹) and the methanotrophic diversity markedly increased in treatments with a pre-incubation at elevated CH₄ concentrations. In all soils and treatments, type II methanotrophs (62–91%) outnumbered type I methanotrophs (9–38%). Methylocystis and Methylosinus species were always most abundant. After pre-incubation with ammonium, CH₄ oxidation was completely inhibited; however, no change in the methanotrophic community structure could be detected.     

Effects of Cd and Pb on the survival and juvenile production of Sinella coeca and Folsomia candida

Degradation factors can cause both quantitative and qualitative changes in fauna and thus affect soil functioning. The use of bio-indicators may help to detect environmental changes. The aim of this study was to evaluate the effects of lead and cadmium on the biology (mortality, reproduction, egg hatching) of two euedaphic collembolans, Sinella coeca and Folsomia candida and to evaluate sensitivity differences between the two species. The results showed that low concentrations of lead did not cause dramatic effects on the survival and reproduction of both species. Reproduction of both species was reduced when the soil contained a nominal concentration of Pb at 1000 μg g^–1. S. coeca and F. candida showed a high sensitivity to cadmium and both their reproduction and survival were significantly reduced on exposure to 50 μg g^–1. Moreover, egg hatching of F. candida was affected by the cadmium concentrations in the soil, and by the amount of time that the eggs stayed in contact with cadmium. This study showed that the inhibition determined by Cd on F. candida juvenile production was caused in part by inhibition of deposition and, in part, by reduction of egg viability.     

Diversity among landraces of Indian snapmelon (<Emphasis Type="Italic">Cucumis melo</Emphasis> var. <Emphasis Type="Italic">momordica</Emphasis>)

Diversity among 36 snapmelon landraces, collected from 2 agro-ecological regions of India (9 agro-climatic sub-regions), was assayed using RAPD primers, morphological traits of plant habit and fruit, 2 yield-associated traits, pest and disease resistance and biochemical composition (TSS, ascorbic acid, titrable acidity). Typical differences among accessions were observed in plant and fruit characteristics and snapmelon germplasm with high titrable acidity and possessing resistance to downy mildew, Cucumber mosaic virus, Zucchini yellow mosaic virus, Papaya ringspot virus, Aphis gossypii and Meloidogyne incognita was noticed in the collection. RAPD based grouping analysis revealed that Indian snapmelon was rich in genetic variation and region and sub-region approach should be followed across India for acquisition of additional melon landraces. Accessions of var. agrestis and var. momordica clustered together and there was a separate cluster of the accessions of var. reticulatus. Comparative analysis of the genetic variability among Indian snapmelons and an array of previously characterized reference accessions of melon from Spain, Israel, Korea, Japan, Maldives, Iraq, Pakistan and India using SSRs showed that Indian snapmelon germplasm contained a high degree of unique genetic variability which was needed to be preserved to broaden the genetic base of melon germplasm available with the scientific community. N. P. S. Dhillon and Ranjana contributed equally to this work and are considered the first authors.     

Aspects of the evolution of <Emphasis Type="Italic">Nicotiana tabacum</Emphasis> L. and the status of the United States <Emphasis Type="Italic">Nicotiana</Emphasis> Germplasm Collection

The genus Nicotiana is a member of the nightshade (Solanaceae) family, and is comprised of 70 currently recognized, naturally occurring species. Genetic variability within N. tabacum L., the species of primary economic importance, was likely affected by several genetic bottlenecks. Nicotiana tabacum is a classic amphidiploid that arose after chance interspecific hybridization between N. sylvestris Spegazinni et Comes and a member of section Tomentosae, likely N. tomentosiformis Goodspeed, N. otophora Grisebach, or an introgressive hybrid between the two. Only a fraction of the genetic variability that existed in the diploid progenitor gene pools probably entered into N. tabacum. Genetic drift, coupled with natural and human selection, subsequently resulted in the formation of narrow genetic pools corresponding to modern commercial market classes. Genetic variability in Nicotiana has gained increased attention in recent years because of investment in Nicotiana genomics research, interest in development of tobacco products with reduced harm characteristics, and concentration on using Nicotiana species for plant-based production of commercially useful proteins. A storehouse of genetic diversity for N. tabacum is available in approximately 1,900 accessions maintained by the United States Nicotiana Germplasm Collection. Seeds of 224 accessions representing 59 wild Nicotiana species are also maintained. The collection is currently maintained by North Carolina State University and is part of the United States National Plant Germplasm System (NPGS). The collection’s curator satisfies hundreds of seed requests made annually by scientists using Nicotiana germplasm for basic biological investigations and by researchers in the area of applied tobacco science.     

Characterization of Portuguese populations of <Emphasis Type="Italic">Vitis vinifera</Emphasis> L. ssp. <Emphasis Type="Italic">sylvestris</Emphasis> (Gmelin) Hegi

Wild populations of Vitis vinifera L.␣have been located in Portugal. Morphological characterization was carried out in three populations located in Alcácer do Sal, Castelo Branco, and Montemor-o-Novo, and then compared using multivariate discriminant analysis. These populations were from three different hydrological basins, therefore cross-pollination was not possible. It was verified that in each population all plants were different. The data suggest that the frequency of female and male plants is rather variable in wild populations. The morphology of the adult leaf, from the Alcácer do Sal population, had particular features when compared with Castelo Branco and Montemor-o-Novo populations, which were more homogeneous. The length of teeth compared with width at the end of the base, and the density of prostrate hairs between and on main veins (lower side) were the variables which allowed the best discrimination among populations.     

of Goat Follicle-stimulating Hormone Receptor (FSHR) Gene

利用PCR-SSCP技术检测山羊(Capra hircus)包括西农萨能奶山羊、关中奶山羊、陕南白山羊、安哥拉山羊和波尔山羊173个个体FSHR基因第10外显子的单核苷酸多态性 (SNP)。结果未发现SNP位点。测序后获得山羊FSHR基因第10外显子的核苷酸序列， 并在NCBI数据库中获得GenBank登录No.DQ069909和DQ069910。通过DNA序列分析发现， FSHR基因第10外显子第120位碱基不存在C→T的转换，也不存在颠换等其它遗传变化。山羊、绵羊 (Ovisaries L.) 和普通牛( Bos taurus) FSHR基因第10外显子序列同源性比较和聚类分析结果表明，山羊、普通牛和绵羊该部分序列的相似性最高为99.3%；在物种间比较中，绵羊和普通牛纯合子该基因外显子序列的不相似性最高为3.4%；据FSHR基因外显子序列构建的分子系统树结果显示，山羊、绵羊和普通牛物种内的个体各自聚为一类；山羊和绵羊先聚为一类，然后再与普通牛聚为一类。提示FSHR基因第10外显子的核苷酸序列适合于物种间的动物分子树的构建。     

A preliminary study of the genetic diversity of Bolivian oca (<Emphasis Type="Italic">Oxalis tuberosa</Emphasis> Mol.) varieties maintained<Emphasis Type="Italic"> in situ</Emphasis> and<Emphasis Type="Italic"> ex situ</Emphasis> through the utilization of ISSR molecular markers

ISSR molecular markers have been used to investigate genetic diversity of oca (Oxalis tuberosa Mol.), an Andean neglected tuber crop species. Sampling procedure allowed a preliminary study of the genetic diversity at the intra- and intervarietal levels. Twenty tuber lots conserved in situ in the microcentre of Candelaria and ex situ in the Toralapa Centre (Bolivia) were identified. Four ISSR primers amplified a total of 25 fragments of which 17 (68%) were polymorphic. These experiments show that the structure of oca varieties is mainly based upon vernacular names with a greater differentiation among tuber lots than within them, supporting agromorphological data. ISSR technique enlightened the existence of heterogeneous varieties in oca and divergence between in situ and ex situ conservation strategies. These observations are potentially linked to the different ways of management of tubers in these two conservation systems.     

Analysis of Genetic Variation Among Accessions of <Emphasis Type="Italic">Pueraria montana</Emphasis> (Lour.) Merr. var. <Emphasis Type="Italic">lobata</Emphasis> and <Emphasis Type="Italic">Pueraria phaseoloides</Emphasis> (Roxb.) Benth. based on RAPD Markers

Pueraria montana var. lobata and P. phaseoloides originating from tropical Asia and parts of Oceania are ecologically and economically important legumes that are used as green manure, cover crop or forage plants. Conservation and use of plant genetic resources require an understanding of the extent and distribution of genetic diversity in any given region. In this study, genetic variation of five P. montana var. lobata and 16 P. phaseoloides accessions was analysed developing a random amplified polymorphic DNA (RAPD) marker methodology for Pueraria species and thereby creating basic data for follow-up research and the development of conservation strategies. Seeds were collected from native populations in Bac Kan Province, a mountainous region in Northeast Vietnam. P. montana var. lobata presented a high level of variation with 54.3% of the detected markers being polymorphic, whereas P. phaseoloides exhibited an intermediate to high level of variation (45.5%). The P. montana var. lobata accessions clustered in congruence with their eco-geographical origin. For P. phaseoloides no correspondence between sampling sites and genetic differentiation was found. Inter-population differentiation was measured as Jaccard's similarity coefficient (JSC). Mean JSC amounted to 0.35 in P. montana var. lobata and 0.52 in P. phaseoloides. Results are compared to other genetic studies of herbaceous legumes and conservation strategies are suggested.     

AFLP similarities among historic Danish cultivars of fodder beet (<Emphasis Type="Italic">Beta vulgaris</Emphasis> L. subsp. <Emphasis Type="Italic">vulgaris</Emphasis>var. <Emphasis Type="Italic">rapacea</Emphasis> Koch)

Dead seeds of a fodder beet cultivar ‘Elvetham’ stored under ambient conditions since 1880 were compared to a homonymous sample preserved in an on-farm situation in Denmark. DNA was isolated from single seeds and successfully applied to Amplified Fragment Length Polymorphism (AFLP) analysis of the accessions. Six primer pairs were used to determine the similarity between the two accessions based on 112 polymorphic bands. Furthermore, similarity among seven cultivars of fodder beets representing the main types used in Scandinavia at the end of the 19th century was determined. This analysis was based on 152 polymorphic bands. Differentiation among the seven cultivars was determined to a mean G _ST value of 0.438, while G _ST between the two ‘Elvetham’ accessions was 0.266. A principal coordinate analysis based on jaccards similarity index illustrates that the two ‘Elvetham’ accessions are different from each other. The differentiation is higher than the value found between two separate ‘Eckerndorfer’ accessions. The results indicate that the cultivated accession has changed. Additionally, the value of applying old dead seed material for documentation in gene banks is demonstrated. During the analysis it was found that DNA isolated from seeds and leaves behaved differently in the AFLP process, however, the two fractions assigned to their common accession.     

The effect of two ant species Lasius niger and Lasius flavus on soil properties in two contrasting habitats

Ants significantly change the soil environment within the nest. The aim of this study is to contribute to ecology and thus the importance of two ant species Lasius niger and Lasius flavus in a post-mining landscape near the town of Sokolov in northwest Bohemia where both species are common. Chemical (total C, N, and available P) and microbiological parameters (respiration, cellulose decomposition and direct counts of bacteria) were investigated in both ant species in two different habitats: a tertiary clay heap after brown coal mining with a weakly developed organic layer and semi natural meadows with well developed organic horizons. Total C and N in the L. flavus mound was lower than in the surrounding soil in both stands, the same was true for total N in L. niger on the heaps. L. niger nests in both sites were significantly enriched by available P. A litter bag test with cellulose indicated lower decomposition in the ant nest in comparison with the surrounding soil. Respiration seems to be limited by lower soil moisture in the nest. However, microbial respiration, even in suitable moisture conditions, did not differ between the nest and soil (on heaps) or nest respiration was significantly lower (in L. flavus nests in the meadow). In meadow soil both species had a lower bacteria count than the surrounding soil, but the L. niger nest on the heap had higher bacterial numbers. Both species significantly alter soil conditions, although the effect on selected parameters is variable. Moreover, the result with lower nest moisture and lower decomposition rate in ant mounds indicates that soil moisture should be the next important factor limiting soil processes inside ant mounds.     

Production and analysis of reciprocal hybrids between <Emphasis Type="Italic">Asparagus officinalis</Emphasis> L. and <Emphasis Type="Italic">A. schoberioides</Emphasis> Kunth

The genus Asparagus (Asparagaceae) encompasses 100–300 species, including the important vegetable crop, A. officinalis (garden asparagus). Previous attempts to hybridize garden asparagus with A. densiflorus (Kunth) Jessop, with the aim of introducing disease resistance, were unsuccessful because of the failure of endosperm development. In the present study, reciprocal interspecific hybrids between garden asparagus and A. schoberioides Kunth were generated by hand pollination. The F1 hybrids were analyzed by using both morphological and molecular techniques. This is the first report describing the production of an interspecific hybrid between garden asparagus at the diploid level (2n = 2x = 20) and its diploid (2n = 2x = 20) wild relative, A. schoberioides. Morphological characteristics of candidate hybrids were a mixture of those found in the parents, and cytological and RFLP analyses confirmed that morphologically intermediate plants were indeed diploid hybrids of those two species. In other words, post-zygotic isolation is not complete between phylogenetically distinct these two species. Our results suggest that other Asparagus species may be capable of hybridizing with A. officinalis and that introducing wild characters through interspecific hybridization may offer advantages for breeding for novel traits. Takuro Ito and Toshinori Ochiai authors are contributed equally to this work