培养基铁浓度对不同非共生固氮菌株与小麦基因型联合固氮效率的影响

采用Ｓｐｅｒｍｏｓｐｈｅｒｅｍｏｄｅｌｓ测定５种培养基铁浓度下两株非共生固氮菌（巴西固氮螺菌ＮＯ４０和多粘芽孢杆菌）及两者的混合菌分别与两个小麦基因型（Ｇｉｚａ１６７和Ｓａｋｈａ８）的联合固氮效率，发现培养基的铁浓度对联合固氮效率具有显著的影响．若不考虑菌株间和小麦基因型间的差异，培养基铁浓度在２．５８３～１４．７１５ｍｇ／Ｌ时的联合固氮效率显著高于铁浓度为４２．８８３～１６６．３１ｍｇ／Ｌ；联合固氮效率在小麦基因型间未表现出显著差异，但在不同菌株之间差异极显著．表现为：巴西固氮螺菌＞混合菌＞多粘芽孢杆菌；联合固氮效率在培养基铁浓度与不同菌株之间存在明显的交互作用，巴西固氮螺菌对铁浓度的适应范围比多粘芽孢杆菌及混合菌广，在固氮高峰期巴西固氮螺菌与小麦基因型Ｇｉｚａ１６７组合的联合固氮效率在５种供试铁浓度下均达较高水平而未表现出显著的差异，巴西固氮螺菌与Ｓａｋｈａ８组合的联合固氮效率在铁浓度为２．５８３～４２．８８３ｍｇ／Ｌ时最高．说明巴西固氮螺菌ＮＯ４０对培养基中供铁水平的适应范围较广，因而具有良好的应用前景．     

Hydrogen storage in microporous metal-organic frameworks

Metal-organic framework-5 (MOF-5) of composition Zn4O(BDC)3 (BDC = 1,4-benzenedicarboxylate) with a cubic three-dimensional extended porous structure adsorbed hydrogen up to 4.5 weight percent (17.2 hydrogen molecules per formula unit) at 78 kelvin and 1.0 weight percent at room temperature and pressure of 20 bar. Inelastic neutron scattering spectroscopy of the rotational transitions of the adsorbed hydrogen molecules indicates the presence of two well-defined binding sites (termed I and II), which we associate with hydrogen binding to zinc and the BDC linker, respectively. Preliminary studies on topologically similar isoreticular metal-organic framework-6 and -8 (IRMOF-6 and -8) having cyclobutylbenzene and naphthalene linkers, respectively, gave approximately double and quadruple (2.0 weight percent) the uptake found for MOF-5 at room temperature and 10 bar.     

Disruption of the CFTR gene produces a model of cystic fibrosis in newborn pigs

Almost two decades after CFTR was identified as the gene responsible for cystic fibrosis (CF), we still lack answers to many questions about the pathogenesis of the disease, and it remains incurable. Mice with a disrupted CFTR gene have greatly facilitated CF studies, but the mutant mice do not develop the characteristic manifestations of human CF, including abnormalities of the pancreas, lung, intestine, liver, and other organs. Because pigs share many anatomical and physiological features with humans, we generated pigs with a targeted disruption of both CFTR alleles. Newborn pigs lacking CFTR exhibited defective chloride transport and developed meconium ileus, exocrine pancreatic destruction, and focal biliary cirrhosis, replicating abnormalities seen in newborn humans with CF. The pig model may provide opportunities to address persistent questions about CF pathogenesis and accelerate discovery of strategies for prevention and treatment.     

Dietary Supplementation of Brown Seaweed and/or Nucleotides Improved Shrimp Performance,Health Status and Cold-Tolerant Gene Expression of Juvenile Whiteleg Shrimp during the Winter Season

This study was aimed to evaluate the efficiency of Sargassum polycystum and nucleotides- supplemented diets to improve immune response and cold-tolerance of juvenile Litopenaeus vannamei. Four treatments were evaluated: T1, the control, shrimp received only a basal diet; T2, a basal diet with 500 ppm nucleotides; T3, a basal diet with 500 ppm S. polycystum powdered; T4, a basal diet with 500 ppm nucleotides and 500 ppm S. polycystum powdered. Shrimp were fed experimental diets for 56 days. Results revealed shrimp fed T4 diet exhibited the best significant improvement in water quality, survival, growth, and feed utilization indices followed by T2, and T3, while T1 showed the worst values. Additionally, nonspecific immune responses (phagocytosis (%), lysozyme, phenoloxidase, super oxide dismutase (SOD) activity, total nitric oxide) were improved with 1.7–3.2-fold in T4 higher than T1. Histomorphology of hepatopancreas in T4 showed the most increased activation of the hepatic glandular duct system compared with the other treatments. Moreover, nucleotides/seaweed-supplemented diets upregulated relative expression of cMnSOD, Penaeidin4, and heat shock protein70 (HSP70) genes, while translationally controlled tumor protein (TCTP) was downregulated. In conclusion, the synergistic effects of both S. polycystum and nucleotides have many advantages as a growth promoter, immunostimulant, antimicrobial, and cold-tolerant stimulant to L. vannamei.     

Carbon and nitrogen supplementation to soybean through stem injection and its effect on soybean plant senescence

Plant senescence studies have indicated that internal competition for nutrients such as carbon (C) and nitrogen (N) can be an important factor in the initiation of senescence. A greenhouse experiment was conducted to determine the effect of increased supplies of C and N on senescence of soybean (Glycine max [L.] Merr) plants. Soybean plants were injected with solutions of sucrose (150gL^‐1), N (15 mM N), and distilled water from the onset of flowering until senescence using a modified stem injection technique. The average uptake rate of all solutions was 1.3 mL d^‐1 per plant. The plants injected with sucrose accumulated the most biomass, followed by those injected with N and distilled water. Soybean plants injected with sucrose senesced 17 days later than the distilled water control while senescence was not delayed for plants injected with N. Injection of either N or sucrose increased the concentration and content of N in soybean plants. The results indicated that intra‐plant‐competition for reduced C plays an important role in plant senescence. Because the total amount of N injected was only 2% of the total plant N, as compared to 31 % for C, the role of intra‐plant competition for N was less clear.     

Porewater Monitoring Under Different Layer Systems on a Sloping Surface at a Closed Mine Site

In this study, we investigate the corrosion effects on modern materials at various sheltered and unsheltered locations in the Greater Athens Area (GAA) due to atmospheric pollution, since materials deterioration could emerge severe economic costs in the near future. The preselected materials are weathering steel, copper, bronze, zinc, and aluminum, which are mainly used in modern constructions in the GAA. The method applied in this study leads in the production of corrosion maps for GAA in the period 2000–2009 by using sophisticated geoanalytical methods together with dose–response functions for the selected materials. The corrosion effects are significant for weathering steel, moderate for copper and bronze and weak for zinc and aluminum. Also, a corrosion trend analysis is performed, which can be a very helpful tool for future protection of such materials from atmospheric pollution. The results show increasing corrosion trends for weathering steel and copper in the eastern regions of GAA, probably caused by the recent operation of the Athens International Airport at Spata, while no corrosion trends were observed to the other materials. The method applied in this work provides comprehensive results for the estimation of the impact of atmospheric corrosion on various construction materials.     

Correction to: Assessment of cable tensile forces in active winch-assist harvesting using an anchor machine configuration

European Journal of Forest Research - A correction to this paper has been published: https://doi.org/10.1007/s10342-021-01385-w     

Morphological characterization of Pelibuey sheep in Colima, México

A study was conducted with the objective to characterize the morphology of Pelibuey sheep in the state of Colima, Mexico. A total of 386 sheep were scored for 12 body measurements in addition to live weight and five racial and eight functional indices were calculated. The influence of sex on the body measurements and indices was analyzed, and morphological harmony was determined through Pearson correlation. The sexual dimorphism was 1.21, with males being 67 % heavier than females. Females and males had a high and moderate degree of harmony in their morphological model, respectively. Pelibuey sheep were dolichocephalous, tended to be medium- to large-sized according to the thoracic index, with a convex curve rump; they were a homogeneous breed, well adapted to environmental and production conditions of the state of Colima, Mexico, and show an undefined zootechnical aptitude and therefore a great potential to be oriented towards meat or milk production through genetic selection or terminal crossbreeding systems using specialized breeds.     

Introduction of Xa21, a Xanthomonas-resistance gene from rice,into ‘Hamlin’ sweet orange [Citrus sinensis (L.) Osbeck] using protoplast-GFP co-transformation or single plasmid transformation

Summary

Plasmid DNA (pARS108) containing the non-destructive selectable marker Green Fluorescent Protein (GFP) gene, and a plasmid containing a cDNA of the Xa21 gene from rice (pXa21-mtaq) were co-transformed into ‘Hamlin’ orange protoplasts using polyethylene glycol (PEG). Alternatively, plasmid DNA (pAO3), containing both genes (GFP and Xa21) was directly transformed into ‘Hamlin’ orange protoplasts. Over 1,000 transgenic plantlets were regenerated from approx. 80 independent transformation events. The transgenic plants showed normal growth and stable GFP expression over more than 2 years in the greenhouse. This is the first report of a large population of transgenic ‘Hamlin’ sweet orange plants containing one or more target gene(s), using a protoplast-GFP transformation system. Polymerase chain reaction (PCR) revealed the presence of the Xa21 cDNA and the GFP genes in all single plasmid transformed plants, and in 35% of the co-transformed plants. Southern blot analysis showed the integration of the cDNA into one-to-five different sites per plant.Western blot analysis showed the accumulation of the rice XA21 protein in the transgenic sweet orange plants. This is the first time that a gene from rice has been stably integrated and expressed in sweet orange plants. Using the protoplast-GFP transformation system, it is possible to avoid the use of Agrobacterium, antibiotic resistance genes, and destructive assay systems.     

Selected health and management issues facing working donkeys presented for veterinary treatment in rural Mexico: some possible risk factors and potential intervention strategies

The examination of 216 donkeys presented for treatment at the Donkey Sanctuary–World Horse Welfare–Universidad Nacional Autonoma de Mexico mobile clinics revealed a number of health and welfare problems. A general overview of the donkeys’ health was made and showed that the median body condition score (BCS) in this population was 2.5. Underweight animals only accounted for 26% of the population. Females, 0–5-year-olds and >21-year-olds, were more likely to be underweight. When analysed, there was no correlation between faecal worm egg count (FEC) and BCS. The prevalence of strongyle infection as assessed by FEC was shown to be 80% with a median FEC of 600 eggs per gramme. Donkeys were assessed for body lesions and showed a high prevalence (71%), particularly in the facial region (54%). Analysis showed that mature animals (6–15 years old) were at increased risk of body lesions compared to older animals (16+ years old) as were donkeys with dental disease and those in particular villages. Risk factor analysis for lesions of the face showed that stallions and geldings are at increased risk as were donkeys wearing halters made from nylon rope. This study has identified areas for further investigation and potential areas where targeted interventions may be made to improve the health and welfare of working donkeys in Mexico.