Carbon dioxide production and oxygen consumption during the early decomposition of different litter types over a range of temperatures in soil‐inoculated quartz sand

Oat straw, hay, and alfalfa litter, differing in microbial colonization and recalcitrance, were added to organic matter–free quartz sand (5 mg C [g material]^–1) and incubated in the laboratory at 5°C, 10°C, 15°C, 20°C, and 25°C. Different incubation periods were chosen so that theoretically the same amounts of CO₂ would be produced and the same amounts of O₂ would be consumed for each litter type. It was investigated whether Q₁₀ values (change in respiration rate between two temperatures) increase with decreasing temperature and how much these Q₁₀ values and also the respiratory quotient (RQ: mol CO₂/mol O₂) depend on the litter type. The sums of CO₂‐C evolved and O₂ consumed, but also the contents of microbial biomass C and microbial biomass N showed a nearly 7‐fold increase in the order oat straw < hay < alfalfa litter. In contrast, the ratio of the fungal cell‐membrane component ergosterol to microbial biomass C was highest in the oat straw (4.1‰) and lowest in the alfalfa litter (0.2‰). This ratio reached a similar level between 5°C and 15°C (1.9‰), significantly higher (p = 0.01) than the level at 20°C (0.9‰). Respiration was similar between 20°C and 25°C, with a mean Q₁₀ value of 1.9. The use of temperature rate‐modifying factors suggested by the carbon‐turnover model ROTHC revealed that the incubation period for similar respiration rates was underestimated at 5°C and overestimated at 25°C. The lignin‐poor and protein‐rich alfalfa litter showed the highest Q₁₀ values of the three litter types in the medium temperature range of 10°C to 20°C. In contrast, the lignin‐rich and protein‐poor oat straw showed significantly highest Q₁₀ values at 5°C and 25°C in comparison with the other two litter types. The RQ was significantly highest in the hay litter (1.05) and in comparison with alfalfa litter (0.97) and oat straw (0.92). Strong temperature‐dependent variations in Q₁₀ values and respiratory quotients suggest interactions between litter quality, microbial colonization of litter, and temperature, which warrants further investigation.     

Effects of different cyclooxygenase inhibitors on prostaglandin E2 production,steroidogenesis and ovulation of bovine preovulatory follicles

Ovulation is an inflammation-like process, and cyclooxygenase-2 (COX-2)-dependent production of prostaglandin E₂ (PGE₂) is its key mediator. Balanced regulation of inflammatory processes in high-yielding dairy cows may be essential for physiological ovulation and fertility. This study aimed to elucidate the mechanisms underlying ovulation failure and cyst development after disturbing intrafollicular inflammatory cascades. Therefore, nonselective (indomethacin and flunixin-meglumine), COX-2 selective (meloxicam), and highly COX-2 selective (NS-398) inhibitors were injected into preovulatory follicles 16 h after administration of GnRH, and ovulation was monitored via ultrasound examination. Additionally, follicular fluid was collected after injection of indomethacin, meloxicam, and NS-398. Moreover, primary granulosa cell cultures from preovulatory follicles were prepared and treated with indomethacin, meloxicam, and NS-398. The concentrations of 17β-estradiol, progesterone, and prostaglandin E₂ (PGE₂) in the follicular fluid and cell supernatant were estimated. Indomethacin and flunixin-meglumine blocked ovulation, even at low doses, and led to ovarian cyst development. The selective and highly selective COX-2 inhibitors meloxicam and NS-398 were not effective in blocking ovulation. However, indomethacin, meloxicam, and NS-398 significantly and comparably reduced PGE₂ concentration in vivo and in vitro (P < 0.05) but had no effect on estradiol or progesterone production. This may contradict the generally accepted hypothesis that PGE₂ is a key mediator of ovulation and progesterone production. Our results suggest a connection between ovarian disorders and inflammatory actions in early postpartum cows.     

Organic fertilizers derived from plant materials Part I: Turnover in soil at low and moderate temperatures

The aim was to investigate different organic fertilizers derived from plant materials with respect to their nitrogen and carbon turnover in soil in comparison with organic fertilizers derived from animal‐waste products. In a 64‐day incubation study at 5°C and 15°C, the following fertilizers were used: coarse faba bean–seed meal (Vicia faba L.), coarse meals of yellow and white lupin seeds (Lupinus albus L. and Lupinus luteus L.), Phytoperls^® (waste products of maize [Zea mays L.] processing), coarse meal of castor cake (Ricinus communis L.) as a widely used organic fertilizer, and horn meal as a reference fertilizer‐derived from animal waste products. At 15°C, horn meal showed the highest apparent net N mineralization of fertilizer‐derived N, followed by castor cake and the two lupin meals. At 5°C, apparent net N mineralization of fertilizer‐derived N from horn meal and coarse meal of yellow lupin seeds was nearly identical, followed by castor‐cake meal. Net N mineralization from legume‐seed meals showed no or even a negative temperature response, at least temporarily. In contrast, the other fertilizers showed a positive temperature response of net N mineralization. The content in recalcitrant structural components and the decoupling of decomposition of N‐rich and C‐rich tissue components in time are discussed as controlling factors of fertilizer‐N turnover at low temperature. Microbial residues seem to be an important temporary sink of fertilizer‐derived C and N. Legume‐seed meals induced considerable N‐priming effects. Temperature induced differences in the decomposition of total fertilizer C, indicated by changes in the sum of cumulative CO₂‐C evolution, total K₂SO₄‐soluble organic C and microbial‐biomass C were much smaller than indicated by cumulative CO₂‐C evolution alone. Our results indicate that legume‐seed meals have the potential to replace horn meal and castor‐cake meal in organic vegetable production, especially when soil temperatures in early spring are still low.     

Use of microcalorimetry to study microbial activity during the transition from oxic to anoxic conditions

Microbial heat production is a nonspecific measure for microbial activity irrespective of O₂ availability in soils. In a series of long-term batch microcalorimeter experiments with closed ampoules, we examined the microbial activity in glucose-amended soil aggregates from different soil depths of a clay forest soil during the transition from aerobic to anaerobic conditions. Furthermore, the influence of the soil aggregate size on the long-term metabolic heat production was examined. Heat output curves showed a distinct pattern for soil samples from different soil depths and aggregate sizes and led to the following conclusions: 1. Microbial biomass and microbial activity strongly decreased with increasing soil depth as well as increasing soil aggregate size despite relatively constant organic C concentrations. 2. The transition from aerobic to anaerobic conditions led to a considerable drop in microbial activity. However, based on the energy balance, 10-26% of the heat production during the aerobic phase is attributable to anoxic or partly anoxic metabolism. 3. After O₂ exhaustion, a lag phase of low but constant heat output was observed, followed by a peak of anaerobic metabolic activity. Heat production during the lag phase was hypothesised to be an indicator for the biomass of facultatively anaerobic microorganisms in the soil.     

Pattern of seroreactivity against feline foamy virus proteins in domestic cats from Germany

The prevalence of feline foamy virus (FFV, spumaretrovirinae) in naturally infected domestic cats ranges between 30 and 80% FFV positive animals depending on age, sex and geographical region analyzed. Two serotypes have been reported for FFV designated FUV7-like and F17/951-like. Serotype-specific neutralization has been shown to correlate with sequence divergence in the surface (SU) domain of the envelope protein (Env). We analyzed a serum collection of 262 domestic cat sera from Germany using a GST-capture ELISA setup screening for Gag and Bet specific antibodies and identified 39% FFV positive animals. Due to the heterogeneity of the serological samples, cut-offs for Gag and Bet reactivity had to be experimentally determined since application of calculated cut-off values yielded some false-positive results; the new cut-off values turned out to be also fully applicable to a previous study. Using the already established FUV7 ElpSU antigen and the newly cloned and produced F17/951 ElpSU antigen, both consisting of the corresponding ectodomains of the envelope leader protein (Elp) and SU protein, we aimed at the detection of Env-specific antibodies and discrimination between the two known FFV serotypes within the diagnostic FFV ELISA. We validated the ElpSU antigens using cat reference sera of known serotype and screened with this assay domestic cat sera from Germany. Use of the FUV7- and F17/951 ElpSU antigens in ELISA resulted in the detection of Env-specific antibodies in both cat reference sera and sera from domestic cats in Germany, but failed to allow serotyping at the same time.     

Milk production systems in Central Uganda: a farm economic analysis

The Ugandan dairy sector is developing rapidly over recent years and is dominated by small-scale farmers owning more than 90 percent of the national cattle population. Due to market forces and higher competition for production factors, milk production systems are intensifying, necessitating proper understanding of the new production tendencies. Three intensive and four extensive production systems were identified and analysed, using TIPI-CAL (Technology Impact Policy Impact Calculations model). The results show that the production systems are very different in many respects but share similar development trends. Whereas intensive systems use graded animals and invest heavily into feeding, buildings and machinery, extensive systems use local breeds and invest minimally. Total cost of milk production falls with increasing herd size, while dairy returns vary among farms from 18 to 35 USD/100 Kg of milk. All systems make an economic profit, except the intensive one-cow farm, which heavily employs family resources in dairying. Due to better management of resources and access to inputs and markets, dairy farming closer to urban areas and using improved breeds is highly profitable, especially with larger herd sizes. Stakeholders should favour such practices as well as others which can improve productivity, especially in African countries where traditional systems dominate dairying.     

A clinical study to evaluate the cardiopulmonary characteristics of two different anaesthetic protocols for immobilization of healthy chimpanzees (Pan troglodytes)

Objective

To characterize the cardiopulmonary characteristics of two different anaesthetic protocols (tiletamine/zolazepam ± medetomidine) and their suitability for the immobilization of healthy chimpanzees undergoing cardiac assessment.

Helicusin E,Isochromophilone X and Isochromophilone XI: New Chloroazaphilones Produced by the Fungus Bartalinia robillardoides Strain LF550

Microbial studies of the Mediterranean sponge Tethya aurantium led to the isolation of the fungus Bartalinia robillardoides strain LF550. The strain produced a number of secondary metabolites belonging to the chloroazaphilones. This is the first report on the isolation of chloroazaphilones of a fungal strain belonging to the genus Bartalinia. Besides some known compounds (helicusin A (1) and deacetylsclerotiorin (2)), three new chloroazaphilones (helicusin E (3); isochromophilone X (4) and isochromophilone XI (5)) and one new pentaketide (bartanolide (6)) were isolated. The structure elucidations were based on spectroscopic analyses. All isolated compounds revealed different biological activity spectra against a test panel of four bacteria: three fungi; two tumor cell lines and two enzymes.     

Identification of the antibacterial compound produced by the marine epiphytic bacterium Pseudovibrio sp. D323 and related sponge-associated bacteria

Surface-associated marine bacteria often produce secondary metabolites with antagonistic activities. In this study, tropodithietic acid (TDA) was identified to be responsible for the antibacterial activity of the marine epiphytic bacterium Pseudovibrio sp. D323 and related strains. Phenol was also produced by these bacteria but was not directly related to the antibacterial activity. TDA was shown to effectively inhibit a range of marine bacteria from various phylogenetic groups. However TDA-producers themselves were resistant and are likely to possess resistance mechanism preventing autoinhibition. We propose that TDA in isolate D323 and related eukaryote-associated bacteria plays a role in defending the host organism against unwanted microbial colonisation and, possibly, bacterial pathogens.     

Donor cell lines considerably affect the outcome of somatic nuclear transfer in the case of bovines

Since the first successful nuclear transfer (NT) experiments were carried out, various somatic cell types have been used as donor cells for production of cloned animals. In most experiments, fibroblasts are used since they only need to be isolated and cultivated. Recently, some researchers have shown that different cell cultures from different sources possess different capacities to support preimplantation development of NT embryos. The blastocyst rates obtained in our previous studies varied and were as high as 45% in relation to the number of reconstructed embryos. This led us to question whether the origin and culture conditions of the defined male and female fibroblast lines could be responsible for the differences in developmental potency. Taking all our results into consideration, we conclude that different fibroblast lines recovered from the same tissue and cultivated under equal culture conditions could produce dramatically different blastocyst rates. The influence of cell line itself is higher than the influence of passage number. The observed effects of cell cycle stage, chromosomal aberrations, and diminished vitality are important but not sufficient to discriminate well-qualified nuclear donor cells. We speculate that some epigenetically regulated deviations in the gene expression program are responsible for these phenomena. Explanation of the underlying mechanisms should contribute to better understanding of epigenetic reprogramming and may ultimately assist reprogramming in the laboratory.