Soil CO<Subscript>2</Subscript> sources above a subterranean cave—Pisani rov (Postojna Cave,Slovenia)

Purpose

The objective of this research is to detect abiotic sources of soil CO₂ above a subterranean cave in the Slovenian karst region.

Materials and methods

The research was performed in the forest above Pisani rov (Postojna Cave) near the town of Postojna (SW Slovenia) and also in the cave. Soil gas, atmospheric air and cave air carbon stable isotope composition (δ¹³C_CO2) and CO₂ concentration were measured. Sampling and measurements were performed bi-monthly at the test and control sites above the cave. The abiotic source of soil CO₂ was estimated using a stable isotope mass balance calculation.

Results and discussion

Similar seasonal patterns of soil CO₂ and δ¹³C_CO2 values were observed at both the test and control sites until spring, with higher levels of CO₂ observed in summer and lower in winter. The δ¹³C_CO2 showed the opposite trend, i.e. lower values (?26 to ?20 ‰) in summer and higher values (up to ?17 ‰) in winter and early spring. In spring, the soil CO₂ concentration decreases and the δ¹³C_CO2 value increases only at the control site. A time series of a modelled “isotopically light” endmember revealed large shifts in the data values, due to the presence of an abiotic CO₂ source. Results suggest that the subterranean CO₂ pool and its ventilation is the main source of soil CO₂, accounting for up to 80 % of the soil gas during cold periods.

Conclusions

Ventilation from subterranean cavities is an important source of soil CO₂ in karstic areas and should be taken into account during carbon cycling studies.

     

Intramammary infusion of an Enterococcus faecium SF68 preparation promoted the involution of drying off Holstein cows partly related to neutrophil‐associated matrix metalloproteinase 9

A problem for dairy cows following milk stasis is to cope with a high risk of intramammary infection and there is a need to initiate an extensive renewal of secretory modules in mammary glands so that milk production in next lactation may be optimized. We recently reported that ultrasonicated Enterococcus faecium SF68 (SF68) is compatible with cow mammary glands and an enhancer of innate immunity during the immediate post‐milk stasis period. The current study further examines the concomitant effect of ultrasonicated SF68 on mammary tissue remodeling. Four Holstein cows each received intramammary infusions of regular antibiotic dry‐cow formula (positive control) and two different doses of SF68 in different quarters. Analyses of individual quarter secretion samples showed faster neutrophil infiltration, earlier modifications in protein composition, including caseins and lactoferrins, as well as more prompt elevation of the specific unit of 92‐kDa matrix metalloproteinase 9 (MMP9) in SF68‐infused quarters compared to the positive controls. Intramammary infusion of ultrasonicated SF68 seems able to accelerate the regression of mammary synthetic capacity and potentiate the breakdown of glandular extracellular matrix, indicating a more efficient mammary gland involution. Correlation analyses imply that the ability of ultrasonicated SF68 to induce faster neutrophil chemotaxis and the associated MMP9 release is partly responsible.     

Inorganic and organic carbon dynamics in forested soils developed on contrasting geology in Slovenia—a stable isotope approach

Purpose

Soil carbon dynamics were studied at four different forest stands developed on bedrocks with contrasting geology in Slovenia: one plot on magmatic granodiorite bedrock (IG), two plots on carbonate bedrock in the karstic-dinaric area (CC and CD), and one situated on Pleistocene coalluvial terraces (FGS).

Materials and methods

Throughfall (TF) and soil water were collected monthly at each location from June to November during 2005–2007. In soil water, the following parameters were determined: T, pH, total alkalinity, concentrations of Ca²⁺ and Mg²⁺, dissolved organic carbon (DOC), and Cl^? as well as δ¹³C_DIC. On the other hand, in TF, only the Cl^? content was measured. Soil and plant samples were also collected at forest stands, and stable isotope measurements were performed in soil and plant organic carbon and total nitrogen and in carbonate rocks. The obtained data were used to calculate the dissolved inorganic carbon (DIC) and DOC fluxes. Statistic analyses were carried out to compare sites of different lithologies, at different spatial and temporal scales.

Results and discussion

Decomposition of soil organic matter (SOM) controlled by the climate can explain the ¹³C and ¹⁵?N enrichment in SOM at CC, CD, and FGS, while the soil microbial biomass makes an important contribution to the SOM at IG. The loss of DOC at a soil depth of 5 cm was estimated at 1 mol m^?2 year^?1 and shows no significant differences among the study sites. The DOC fluxes were mainly controlled by physical factors, most notably sorption dynamics, and microbial–DOC relationships. The pH and pCO₂ of the soil solution controlled the DIC fluxes according to carbonate equilibrium reactions. An increased exchange between DIC and atmospheric air was observed for samples from non-carbonate subsoils (IG and FGS). In addition, higher δ¹³C_DIC values up to ?19.4?‰ in the shallow soil water were recorded during the summer as a consequence of isotopic fractionation induced by molecular diffusion of soil CO₂. The δ¹³C_DIC values also suggest that half of the DIC derives from soil CO₂ indicating that 2 to 5 mol m^?2 year^?1 of carbon is lost in the form of dissolved inorganic carbon at CC and CD after carbonate dissolution.

Conclusions

Major difference in soil carbon dynamics between the four forest ecosystems is a result of the combined influence of bedrock geology, soil texture, and the sources of SOM. Water flux was a critical parameter in quantifying carbon depletion rates in dissolved organic and inorganic carbon forms.

     

Inheritance of angular leaf spot resistance in common bean line BAT 332 and identification of RAPD markers linked to the resistance gene

The existence of genetic variability for angular leaf spot (ALS) resistance in the common bean germplasm allows the development of breeding lines resistant to this disease. The BAT 332 line is an important resistance source to common bean ALS. In this work we determined the inheritance pattern and identified RAPD markers linked to a resistance gene present in BAT 332. Populations F₁, F₂,BCs and BCr derived from crosses between BAT 332 and cultivar Rudá were used. Rudá is a commercial cultivar with carioca type grains and susceptible to ALS. The resistance of BAT 332 to race 61.41 of the pathogen was confirmed. Segregation analysis of the plants indicated that a single dominant gene confers resistance. For identification of RAPD markers linked to the resistance gene, bulk segregant analysis (BSA) was used. Two RAPD markers,OPAA07₉₅₀ and OPAO12₉₅₀, linked in coupling phase at 5.10 and 5.83 cM of this gene, respectively, were identified. These molecular markers are important for common bean breeders and geneticists as source of genetic information and for marker assisted selection in breeding programs. This revised version was published online in July 2006 with corrections to the Cover Date.     

Gene flow in common bean (Phaseolus vulgaris L.)

This study was conducted in Brazil in order to assess the potential risk posed by gene escape from transgenic into non-transgenic plants and wild populations. A new methodology was applied to evaluate the gene flow between common bean cultivars, by means of a specially delineated experiment in two stages. The first stage consisted of the planting of one cultivar with violet flowers (BB) as pollen source (‘Diamante Negro’), and a receiver (‘Talismã’) with white flowers (bb), at different distances. The source was sown in the center of the area. The pollen receiver cultivar was sown, in concentrical squares around it. At maturity, the rows were sampled at varied distances from the source in the four cardinal directions. In the second stage, the sampled seeds of the previous stage were sown, and the percentage of outcrossing was evaluated during flowering through the presence of violet flowers (Bb). The highest frequency of natural hybrids, 0.136%, occurred at a distance of 0.5 m between the cultivars. The natural outcrossing rate was practically zero beyond a distance of 3.25 m.     

Expression of foreign genes in chicks by hydrodynamics-based naked plasmid transfer in vivo

The study of gene function in vivo is considered one of the top achievements of modern biology, inasmuch as it provides tools to study gene function in the context of the whole animal. In chickens, techniques of DNA-mediated gene transfer are less advanced than in other animal or livestock models, and remain a significant challenge. The study presented here is the first to show that a hydrodynamics-based gene-transfer technique, originally developed for naked DNA transfer in mice, can be applied to chickens. Rapid injection of naked plasmids containing expression cassettes into the jugular vein of 6- to 10-day-old chicks resulted in specific expression of the transgenes. A CMV promoter-driven luciferase reporter gene was expressed at significant levels in the liver during the first 3 days post-injection with lower levels also detected in the kidney. Significantly, all injected birds showed detectable levels of luciferase expression. Similarly, injection of a plasmid containing the secreted human coagulation factor IX (hFIX) gene under the control of human alpha-1-anti-trypsin promoter resulted in detectable levels of the hFIX in the plasma during the first 2 days post-injection. The method described herein has the potential for a quick and simple route for gain and loss-of function experiments in chicken liver and kidney, as well as for studying systemic effects of secreted proteins and hormones.     

Immunoadjuvant activities of a recombinant chicken IL-12 in chickens vaccinated with Newcastle disease virus recombinant HN protein

Recombinant fowlpox virus (rFPV/HN) expressing Newcastle disease virus (NDV) HN gene and rFPV/HN/chIL-12 co-expressing chicken IL-12 (chIL-12) and HN (rHN/chIL-12) genes have been characterized. rHN/chIL-12 or rchIL-12, expressed by our previous construct rFPV/chIL-12, co-administered with rHN was assessed for adjuvant activities of chIL-12. Chickens were vaccinated with various amounts of rHN/chIL-12 mixed with mineral oil (MO), intramuscularly. Levels of hemagglutination-inhibition (HI) antibody production depended on the concentration of the injected rHN or rHN/chIL-12. The lower HI antibody titers were obtained in chicken groups rHN/chIL-12/7-rHN/chIL-12/9, receiving 60ng rHN/8ng chIL-12 with MO, 30ng rHN/4ng chIL-12 with MO or 15ng rHN/2ng chIL-12 with MO, respectively, compared to those in chicken groups rHN/7-rHN/9, receiving rHN with MO alone. However, chickens in group rHN/chIL-12/7 or rHN/chIL-12/8 and rHN with MO alone showed the same effective protection. Chicken group rHN/chIL-12/9 was even more protective than that in group rHN/9. When rchIL-12 was co-injected with 15ng rHN plus MO, chickens produced low levels of HI antibody titers; while higher levels of IFN-γ production and an effective protection rate (83%) were obtained. On the other hand, low levels of IFN-γ production and low protection response (50%) were obtained in chickens injected with rHN with MO alone. Taken together, when the concentration of rHN decreased to certain levels, rchIL-12 reduced HI antibody production. The increase in the induction of IFN-γ production might suggest the enhancement of the cell-mediated immunity which conferred the protection from the NDV challenge.     

Effects of the 921 earthquake on the water quality in the upper stream at the Guandaushi experimental forest

A powerful 7.3 magnitude earthquake struck Taiwan on September 21, 1999. The stream water chemistry (pH, total alkalinity, conductivity, sodium, potassium, calcium, magnesium, ammonium, fluoride, chloride, sulfate, and nitrate) has been monitored since 1995 at the Guandaushi forestry riparian zone in central Taiwan. Collected data was used as a basis for comparing pre- and post-earthquake impacts. The pH, conductivity, and concentrations of Na, Ca, Mg, SO₄, and HCO₃ in stream water were lowest during the summer season, when stream water discharge was highest. On the other hand, the lowest concentrations of Cl, NH₄, and NO₃ in stream water occurred during the winter season, when stream water discharge was lowest. Also, K and F showed very little seasonal fluctuation in concentration. Downward trends in K and Ca were found 14 months prior to the earthquake; although, an upward trend occurred in NH₄ at the same time.     

Spatial delineation of organic carbon-rich Colluvial soils in Chernozem regions by Terrain analysis and fuzzy classification

Colluvial soils are considered to be the direct result of accelerated soil erosion, resulting in accumulation of humus-rich soil material in terrain depressions and base parts of slopes. The organic carbon concentration in these soils and their depth make them an important organic carbon storage. Mapping the Colluvial soils, therefore, represents an important contribution in total carbon stock estimation. A method of delineating Colluvial soils is proposed by applying a combination of high resolution digital elevation model analysis and detailed field survey. Two models based on fuzzy classification of soil units were created using different topographic derivatives as the only input parameters to predict the Colluvial soil area on a morphologically diverse study site in the Southern Moravia, Czech Republic. The model that considers only the derivatives with a strong relationship to Colluvial soil occurrence reached 71% accuracy in Colluvial area delineation, while the model combining six commonly used derivatives showed less favorable results. The main advantage of the method lies in a low demand of input soil data and its relatively high accuracy.     

狐狸巴氏杆菌病病原的分离与鉴定

巴氏杆菌病又叫出血性败血症，简称出败，主要是由多杀性巴氏杆菌所引起的各种畜禽和野生动物感染的一种传染病。临床特征急性病例主要表现为败血症和炎性出血，慢性特征表现为皮下组织、关节、各脏器的局灶性化脓性炎症。该病常在畜禽中发生，而在狐狸等经济动物方面报道相对较少。2006年秋，吉林左家某狐场的狐狸突然发病并陆续死亡，经流行病学调查、病理剖检和实验室检验，确诊为多杀性巴氏杆菌感染所致。