新疆库米什金矿土壤可培养细菌的多样性分析

[目的]了解新疆库米什一处金矿土壤可培养细菌的多样性及建立菌种资源库.[方法]采集库米什金矿土壤样品,采用两种不同培养基(LB,TSB)分离纯化细菌,对其进行形态观察(菌落及细胞)、生理测定、16SrDNA测序和系统进化分析.[结果]从两种培养基上总共得到50株细菌,根据基于16S rDNA的系统进化分析表明,50株菌分别属于3个大类群:厚壁菌门(Firmicutes ),放线菌门(Actinobacteria),γ-变形菌纲(γ-Proteobaeteria),12个属,30个分类单元.其中芽抱杆菌属(Bacillus)为优势细菌种群,占已测种群的63.3;.菌株L10-5与Bacillus foraminis (AJ717382)有96.463;的相似率,可能为潜在新种.[结论]库米什金矿土壤可培养细菌具有较高的多样性,存在潜在新菌种资源,值得进一步研究.     

Effect of herbicide applications on legume-rhizobium symbiosis

The effect of the application of three herbicide formulations namely: Preforan (2,4-dinitro-4-trifluoromethyl-diphenyl ether), Dacthal (dimethyl 2,3,5,6-tetrachloroterepthalate) and Dual (2,ethyl-6-methyl-N-(2-methoxy-1-ethyl-a-chloro-acetanilide)) on legume-Rhizobium symbiosis was evaluated by incorporating these herbicide formulations into plate agar cultures of two Rhizobium strains and into soil carrying cowpea (Vigna unguiculata (L.) Walp.). Results indicated that Dual is bactericidal — giving the lowest mean cell count for strain TAL 385 in agar culture, 3.04 × 106 compared to 3.51 and 3.43 × 106 for Dacthal and Preforan respectively. In the soil system, while the highest rate of Dacthal and Preforan merely decreased nodulation, Dual highest rate completely killed the plants within 14 days after planting. The rate of herbicide application and the herbicide type were both important factors which affected vital parameters of the legume — Rhizobium symbiosis in soil culture.     

Monitoring Metal Speciation in The rivers Meuse and Rhine Using DGT

Although a number of metal speciation methods are nowadays available, most water quality regulations are based on total metal concentrations. One of the main reasons for the ignorance of speciation is the lack of methods with potentiality for monitoring. Conditions that have to be met by such speciation methods are: simple performance, robust and sufficiently accurate. In this study the potential for monitoring purposes of Diffusive Gradients in Thin films (DGT) is investigated as part of a European project for sensor development for routine prediction of metal biouptake in natural waters. Performance characteristics of DGT have been assessed in experiments under controlled laboratory conditions and during in situ application over 4–9 months under different hydrological conditions in the rivers Meuse and Rhine. Results have been worked out for Cu, Ni and Pb. The study shows that DGT has sufficient potential as a robust tool in routine monitoring to observe trends in water quality. However, it appears that during in situ application of DGT the measurement uncertainty of the results is much larger than under laboratory conditions. The increase in measurement uncertainties will partially be due to uncertainties in some as constant considered factors in the calculation of the DGT concentration. For Cu and Ni, the average values for the reproducibility in the rivers Meuse and Rhine appeared to be 28% and 17%, respectively, whereas under laboratory conditions the reproducibilities for both metals were better than 10%. In the speciation of Cu, Ni and Pb in the rivers Meuse and Rhine, the labile fraction, determined using DGT, decreased in the series Ni, Cu, Pb. The ratio of the non-labile and labile fractions of the metals appeared to decrease with increasing content of Dissolved Organic Carbon (DOC).     

Effect of preparation conditions on protein secondary structure and biofilm formation of kafirin

Various extraction and drying conditions for the isolation of kafirin from dry-milled, whole grain sorghum have been investigated, with a view to optimizing extraction of the protein for commercial food coatings and packaging films. The addition of sodium hydroxide to an aqueous ethanol extractant increased the yield and solubility of kafirin. Subsequent heat drying at 40 degrees C was shown to cause the kafirin to aggregate as indicated by an increase in intermolecular beta-sheets. Extraction of the flour using ethanol (70%, w/w) with 0.5% (w/w) sodium metabisulfite and 0.35% (w/w) sodium hydroxide at 70 degrees C followed by freeze-drying of the protein was found to produce a yield of 54% kafirin with good film-forming properties. The kafirin films were assessed for their sensory properties, tensile strength, strain, and water vapor permeability. Fourier transform infrared spectroscopy was used to study the secondary structure of the extracted kafirins. The best films were made with kafirin containing a large proportion of nativelike alpha-helical structures with little intermolecular beta-sheet content as indicated by the Fourier transform infrared reflectance peak intensity ratios associated with these secondary structures. The principal factor affecting the secondary structure of the protein appeared to be the temperature at which the protein was dried. Heat drying resulted in a greater proportion of intermolecular beta-sheets. Any industrial-scale extraction must therefore minimize protein aggregation and maximize native alpha-helical structures to achieve optimal film quality.     

Morphological study of the lingual papillae in the fruit bat (Rousettus amplexicaudatus) by scanning electron microscopy and light microscopy

This study was carried on the tongues of ten normal, healthy and adult fruit bats (Rousettus amplexicaudatus, also known as the nyap biasa bat) in Yogyakarta, Java Island, Indonesia. The tongue was protrusible, elongated and flat with a rounded apex, and its width and thickness increased gradually towards to lingual root. There were two main types of lingual papillae, mechanical (filiform) and gustatory (fungiform and circumvallate). The tongue was divided into three parts (apex, corpus and radix), and then, each part was subdivided into three regions (two lateral regions and a median region). There were six subtypes of the filiform papillae—three types on the anterior part (small, scale-like and giant), one type on the middle part (leaf-like papillae) and two types on the posterior part (rosette-shaped filiform and conical filiform papillae)—in addition to transitional papillae presented on the corpus and radix. Two types of gustatory papillae were represented by a small number of fungiform papillae that are scattered among the filiform papillae on the lingual apex and corpus, while three circumvallate papillae on the posterior part are arranged in a “V” shape pointing directly at the larynx.     

Analgesic activity of the roots and leaves extracts of Calliandra portoricensis

The analgesic activity of the methanolic extracts of the roots and leaves of Calliandra portoricensis was investigated in mice and rats using acetic acid-induced writhing and formalin tests. The extracts given orally at the doses of 200, 400, 600 mg/kg showed a dose-dependent activity in the tests used.     

Conservation of Zingiber germplasm through in vitro rhizome formation

The effects of various concentrations of maleic hydrazide (MH; 2, 4, 6, 8 mg/l) and three light treatments (16-h, 24-h, 0-h) on in vitro rhizome formation and conservation of ginger (Zingiber officinale Rosc. cv. Rio de Janeiro) were studied. In vitro rhizome formation occurred in all the above treatments. Addition of MH (2–8 mg/l) to the control medium (CM) comprising Murashige and Skoog's (1962) salts, 9% sucrose, 0.8% agar-agar, 0.1 mg/l α-naphthaleneacetic acid (NAA), 1 mg/l N⁶-benzyladenine (BA), did not show any significant positive effects on rhizome formation as well as survival of cultures. A significant effect of light treatments was observed on survival of cultures but not on rhizome formation. More than 50% cultures survived up to 14 months on CM under 16-h and 24-h light conditions as compared to 20% cultures on same medium incubated under dark. A total of 33 genotypes of cultivated and wild species of Zingiber were subsequently tested for conservation through in vitro rhizome formation on CM under 16-h light condition. All genotypes produced rhizomes of varying size with numbers ranging from 3 to 15 per culture and were conserved for at least 12 months; some genotypes could be conserved even up to 16–20 months. Viability of rhizomes was determined by in vitro regeneration of shoots upon subculture and their subsequent establishment in soil. Following the protocol described in the present paper, some 160 genotypes of cultivated and wild species of Zingiber, collected from different geographical regions of India, are being conserved at In Vitro Genebank of National Bureau of Plant Genetic Resources, New Delhi.     

A Promising Potential of Brown Algae Sargassum polycystum as Irreversible Hydrocolloid Impression Material

This study aimed to investigate the potential use of brown algae Sargassum polycystum as irreversible hydrocolloid (alginate) impression material. Potassium alginate extracted from Sargassum polycystum was prepared in three different compositions (14%, 15%, and 16%) and mixed with other standard components to form an alginate impression material. Prior to that, the purity of potassium alginate was quantified with Fourier Transform Infrared Spectroscopy (FTIR) analysis. As a control material, the alginate impression material from a commercially available product was used. All alginate impression materials were then applied to a die stone model. Dimensional accuracy was measured by calculating the mesiodistal width of incisors in the generated dental cast using a digital caliper 0.01 accuracy (five replications). In addition, to evaluate the dimensional stability, the impression results were poured at four different periods (immediately, 5 min, 10 min, and 15 min). An independent t-test was performed to compare the measurement results with p < 0.05 considered significant. Analytical results confirm that the impression material containing 15% potassium alginate gives the best dimensional accuracy similar to control (p > 0.05). Meanwhile, the optimal dimensional stability was produced in the impression material containing 16% potassium alginate. Our study suggested that brown algae Sargassum polycystum has a promising potential to be used as an alginate impression material in clinical application.     

Profitability and downside risk implications of site-specific nitrogen management with respect to wheat grain quality

Precision Agriculture - Profitability analyses of site-specific nitrogen (N) management strategies have often failed to provide satisfying reasons for adoption of precision farming technologies....