Metal mobility and mineral transformations driven by bacterial activity in acidic pit lake sediments: evidence from column experiments and sequential extraction

Journal of Soils and Sediments - Biogeochemical processes occurring in lake sediments are crucial for element cycling. In acidic pit lakes, they play a major role in acidity neutralization and...     

Coarse woody debris and wood-colonizing fungi differences between a reserve stand and a managed forest in the Taborz region of Poland

The aim of this research was to evaluate the amount of woody debris (m3/ha) on the forest floor and the associated wood-colonizing fungi. The study was performed in the Taborz region, known for its Scots pine provenance experiments, against the background of a recently launched Polish legislation to protect the biodiversity on the forest floor in managed (harvested) stands. We investigated a managed stand (136-years-old) and the reserve stand ‘Sosna Taborska’(261-years-old). In the reserve stand, the mean volume of woody debris was six times higher than in the managed forests, i.e. 65 versus 11 m3/ha. In addition, in the reserve stand, the number of fungi taxa colonizing the dead wood was larger than in the managed stands, with a higher number of fruitbodies. Total fungal richness was higher in the reserve than in the managed stand, i.e. 28 versus 12 species. The dominant taxa at both sites were Fomitopsis pinicola and Fomes The aim of this research was to evaluate the amount of woody debris (m^3/ha) on the forest floor and the associated wood-colonizing fungi. The study was performed in the Taborz region, known for its Scots pine provenance experiments, against the background of a recently launched Polish legislation to protect the biodiversity on the forest floor in managed (harvested) stands. We investigated a managed stand (136-years-old) and the reserve stand ‘Sosna Taborska’(261-years-old). In the reserve stand, the mean volume of woody debris was six times higher than in the managed forests, i.e. 65 versus 11 m^3/ha. In addition, in the reserve stand, the number of fungi taxa colonizing the dead wood was larger than in the managed stands, with a higher number of fruitbodies. Total fungal richness was higher in the reserve than in the managed stand, i.e. 28 versus 12 species. The dominant taxa at both sites were Fomitopsis pinicola and Fomes fomentarius, although some taxa were only found in the reserve (e.g., Stereum hirsutum). The volume of woody debris as well as the diversity of fungi in the managed stand were lower than in the reserve, albeit greater than in other Scots pine stands in Poland. These results testify to the gains in biodiversity yielded by the management conservation management approach at the reserve stand.     

Mediterranean diet in relation to body mass index and waist-to-hip ratio

OBJECTIVE: The Mediterranean diet is rich in fat and starch, and hence may be related to overweight. We therefore investigated the relationship between adherence to a Mediterranean diet and body mass index (BMI) and waist-to-hip ratio (WHR). DESIGN AND SETTING: Data were obtained from the control group of a network of case-control studies on cancer conducted in major teaching and general hospitals in four Italian areas between 1991 and 2002. An interviewer-administered validated 78-item food-frequency questionnaire was used to obtain information on the subjects' habitual diet. Information on socio-economic factors, lifestyle habits and anthropometric measures was also collected. A Mediterranean diet score (MDS) was derived on the basis of eight characteristics of the Mediterranean diet. SUBJECTS: Subjects were 6619 patients (3090 men, 3529 women) admitted to hospital for a wide spectrum of acute, non-neoplastic conditions, unrelated to known risk factors for cancer and long-term modifications of diet. RESULTS: In multiple linear regression models adjusted for age, study centre, education, tobacco smoking, occupational physical activity and total energy intake, the MDS was not related to BMI (beta = 0.05 for men and -0.04 for women) or WHR (beta = 0.000 and 0.001, respectively) in both sexes. CONCLUSIONS: Adherence to the major characteristics of the Mediterranean diet is unrelated to BMI and WHR, confirming previous data from Greece and Spain.     

Molecular and morphological delineation of <Emphasis Type="Italic">Longidorus poessneckensis</Emphasis> Altherr, 1974 (Nematoda: Dorylaimida)

The plant–parasitic nematode Longidorus poessneckensis from the Czech Republic was morphologically and molecularly characterised. Molecular analyses were carried out using mitochondrial DNA (cytochrome c oxidase subunit 1—cox1) and ribosomal DNA (ITS2—second internal transcribed spacer, 18S gene and D2/D3 expansion segments of the 28S gene), which were amplified and sequenced. Phylogenetic relationship of L. poessneckensis with three morphologically closely related species, i.e. L. macrosoma, L. helveticus and L. uroshis, was inferred by using maximum likelihood and maximum parsimony methods, with a female of Xiphinema diversicaudatum and a bivulval female of X. vuittenezi as outgroups. All multiple alignments yielded similar basic trees supporting the uniqueness of L. poessneckensis and the validity of the four Longidorus species identified using morphological characters. Phylogenetic analyses revealed that L. poessneckensis is more closely related to L. macrosoma and L. helveticus than to L. uroshis. High inter-population diversity (19%) was observed across the cox1 gene between two populations of L. poessneckensis.     

Mixing properties and dough functionality of transgenic lines of a commercial wheat cultivar expressing the 1Ax1, 1Dx5 and 1Dy10 HMW glutenin subunit genes

In this work we report the effects of the HMW-GS 1Ax1, 1Dx5 and 1Dy10 on the breadmaking quality of the bread wheat cultivar Anza that contains the HMW-GS pairs 1Dx2 + 1Dy12 and 1Bx7* + 1By8, and is null for the Glu-A1 locus. This allows the characterization of individual subunits 1Dx5 and 1Dy10 in the absence of subunit 1Dx5, and the interactions between these subunits and subunits 1Dx2 and 1Dy12 to be determined. Three transgenic lines termed T580, T581 and T590, containing, respectively, the HMW-GS 1Ax1, 1Dx5 and 1Dy10 were characterized over 3 years using a range of widely-used grain and dough testing methods. The transgenic subunits 1Ax1, 1Dx5 and 1Dy10 accounted for 25.2%, 20.3% and 17.9%, respectively, of the total HMW-GS in the three transgenic lines. Although lines T581 and T590 expressed similar levels of subunits 1Dx5 and 1Dy10 they had different effects on other aspects of protein composition, including changes in the ratios of glutenin/gliadin, of HMW/LMW-GS, the 1Dx2/1Dy12, the x-type/y-type HMW-GS and the proportions of high molecular mass glutenin polymers. In contrast, lines transformed to express subunits 1Ax1 and 1Dx5 showed similar changes in protein composition, with higher protein contents and decreased ratios of glutenin/gliadin and 1Dx2/1Dy12. In addition, both transgenic lines showed similar increases in the ratio of x-type/y-type subunits compared to the control line. The transgenic lines were analysed using Farinograph, Mixograph and Alveograph. This confirmed that the expression of all three subunits resulted in increased dough strength (and hence breadmaking quality) of the cultivar Anza. A beneficial effect of subunit 1Dx5 has not been reported previously, transgenic wheat lines expressing this subunit giving overstrong dough unsuitable for breadmaking. However, the expression of subunit 1Dy10 had a greater effect on breadmaking quality than subunits 1Ax1 and 1Dx5. The Farinograph parameters such as dough stability and peak time were increased by 9.2-fold and 2.4-fold, respectively, in line T590 (expressing 1Dy10) with respect to the control line. Similarly, the Mixograph mixing time was increased by four-fold and the resistance breakdown decreased by two-fold in line T590 compared with the control line. The Alveograph W value was also increased by 2.7-fold in line T590 compared to the control line. These transgenic lines are of value for studying the contribution of specific HMW-GS to wheat flour functional properties.     

Preparations of plant origin enhance carbohydrate content in plant tissues of rooted cuttings of rambler roses: Rosa beggeriana ‘Polstjärnan’ and Rosa helenae ‘Semiplena’

During rhizogenesis, carbohydrates are an important source of energy for the plant tissues. It has been hypothesised that phenological phase of the shoot plays a major role in plant's response to rooting stimulants and affects the cuttings’ carbohydrate content. Therefore, the purpose of this study was to evaluate the impact of phenological phase of the shoots and the use of rooting stimulants of plant origin on the relationship between rooting abilities and the carbohydrate content in leaves and stems of cuttings. Single-node stem cuttings of Rosa beggeriana ‘Polstjärnan’ and Rosa helenae ‘Semiplena’ were harvested from shoots in four phenological stages: flower buds closed (P1), flowers open (P2), immediately after petal shedding (P3), and 7–14 days after petal fall (P4). The following rooting enhancers were used: 0.4% indole butyric acid (IBA) (Ukorzeniacz Aaqua); 0.2% naphthalene acetic acid (NAA) (Ukorzeniacz Baqua); Bio Rhizotonic; and Root Juice?; Bio Roots. Controls included untreated cuttings. The contents of reducing and total soluble carbohydrates in leaves and shoots were estimated before and after rooting. The rooting percentage and rooting degree were determined. A relatively high or moderate natural rooting ability without any treatment were shown by R. beggeriana ‘Polstjärnan’ in 63.8%–87.5% and by R. helenae ‘Semiplena’ in 41.3%–72.5% cuttings. IBA and NAA decreased the mean rooting percentage in ‘Polstjärnan’, but increased it for P4 cuttings in ‘Semiplena’. None of the preparations had any impact on the degree of rooting. The mean level of total soluble and reducing sugars in leaves and stems of cuttings before rooting was lower than that of after root formation. The preparations of plant origin positively affected rhizogenesis and sugar contents in plant tissues, but their effect depended on shoot's phenological phase and cultivar. Plant origin preparations may successfully replace those containing IBA or NAA.     

Sources of variation for sustainable field pea breeding

The pea crop (Pisum sativum L.) is a convenient source of plant protein for animal feeding. The objective of this research was to evaluate field pea breeding lines for agronomic performance and seed quality focussed to their use in a sustainable production. Thirty-five field pea breeding lines and six elite cultivars were evaluated for their agronomic value in field in Spain upon 20 traits related to flower, cycle, plant architecture, productivity and seed quality. The lines showed significant differences in all the quantitative traits evaluated and three of them, namely MB-0307, MB-0308, and MB-0319 were chosen to be evaluated, together with the advanced cultivar ZP-1233, in field and in growing chamber for agronomic performance, seed quality and ability for sustainable production. The four accessions displayed high seed protein content that had significant effect of cropping density with averages of 253.6 g kg⁻¹ under low cropping density of 60 plants m⁻² and 259.1 g kg⁻¹ under high cropping density of 90 plants m⁻², therefore, the low cropping density should be regarded as the most convenient. Average yield of the lines MB-0307, MB-0308 and MB-0319 and the cultivar ZP-1233 was fair (197.5 g m⁻²), probably due to the absence of fertilizers and irrigation, aiming for the sustainability of the crop. Intercropping with rye and herbicide application resulted in no differences on the seed yield; therefore, the ability of the breeding lines to grow without herbicide seems to be demonstrated, while the germination of the seeds at low temperature was very good. These results indicate that field pea could be a new protein crop in the North of Spain to satisfy the demand of plant protein for animal feed, based upon adapted breeding lines that combine the ability for growing under sustainable conditions with other desirable agronomic traits maintaining an adequate productivity.     

Nitrous oxide emissions from soil during soybean [(Glycine max (L.) Merrill] crop phenological stages and stubbles decomposition period

The purpose of this study was to evaluate, during the phenological stages of inoculated soybean crop [Glycine max (L.) Merrill], the effect of different N fertilization levels and inoculation with Bradyrhizobium japonicum on N₂O emissions from the soil. Gas emissions were evaluated at field conditions by the static-chamber method. Nitrogen fertilization increased N₂O emissions significantly (P < 0.05). The variable that best explained cumulative N₂O emissions during the whole soybean growing season was the soil nitrate level (r ² = 0.1899; P = 0.0231). Soil moisture presented a greater control on N₂O emissions between the grain-filling period and the crop commercial maturity (r ² = 0.5361; P < 0.0001), which coincided with a positive balance of the available soil N, as a consequence of the decrease in crop requirements and root and nodular decomposition. Only soil soluble carbon (r ² = 0.29; P = 0.019) and moisture (r ² = 0.24; P = 0.039) were correlated with N₂O emissions during the residue decomposition period. The relationship between soil variables and N₂O emissions depended on crop phenological or stubbles decomposition stages.     

Risk factors associated with the prevalence of tuberculosis-like lesions in fenced wild boar and red deer in south central Spain

In recent decades the management of large game mammals has become increasingly intensive in south central Spain (SCS), resulting in complex epidemiological scenarios for disease maintenance, and has probably impeded schemes to eradicate tuberculosis (TB) in domestic livestock. We conducted an analysis of risk factors which investigated associations between the pattern of tuberculosis-like lesions (TBL) in wild boar (Sus scrofa) and red deer (Cervus elaphus) across 19 hunting estates from SCS and an extensive set of variables related to game management, land use and habitat structure. The aggregation of wild boar at artificial watering sites was significantly associated with an increasing risk of detecting TBL in both species, which probably relates to enhanced opportunities for transmission. Aggregation of wild boar at feeding sites was also associated with increased risks of TBL in red deer. Hardwood Quercus spp. forest availability was marginally associated with an increased risk of TB in both species, whereas scrubland cover was associated with a reduced individual risk of TBL in the wild boar. It is concluded that management practices that encourage the aggregation of hosts, and some characteristics of Mediterranean habitats could increase the frequency and probability of both direct and indirect transmission of TB. These findings are of concern for both veterinary and public health authorities, and reveal tuberculosis itself as a potential limiting factor for the development and sustainability of such intensive game management systems in Spanish Mediterranean habitats.     

Molecular analysis of the sex chromosomes of the platyfish Xiphophorus maculatus: Towards the identification of a new type of master sexual regulator in vertebrates

In contrast to mammals and birds, fish display an amazing diversity of genetic sex determination systems, with frequent changes during evolution possibly associated with the emergence of new sex chromosomes and sex‐determining genes. To better understand the molecular and evolutionary mechanisms driving this diversity, several fish models are studied in parallel. Besides the medaka (Oryzias latipes Temminck and Schlegel, 1846) for which the master sex‐determination gene has been identified, one of the most advanced models for studying sex determination is the Southern platyfish (Xiphophorus maculatus, Günther 1966). Xiphophorus maculatus belongs to the Poeciliids, a family of live‐bearing freshwater fish, including platyfish, swordtails and guppies that perfectly illustrates the diversity of genetic sex‐determination mechanisms observed in teleosts. For X. maculatus, bacterial artificial chromosome contigs covering the sex‐determination region of the X and Y sex chromosomes have been constructed. Initial molecular analysis demonstrated that the sex‐determination region is very unstable and frequently undergoes duplications, deletions, inversions and other rearrangements. Eleven gene candidates linked to the master sex‐determining gene have been identified, some of them corresponding to pseudogenes. All putative genes are present on both the X and the Y chromosomes, suggesting a poor degree of differentiation and a young evolutionary age for platyfish sex chromosomes. When compared with other fish and tetrapod genomes, syntenies were detected only with autosomes. This observation supports an independent origin of sex chromosomes, not only in different vertebrate lineages but also between different fish species.