HIV-1 proviral DNA excision using an evolved recombinase

HIV-1 integrates into the host chromosome and persists as a provirus flanked by long terminal repeats (LTRs). To date, treatment regimens primarily target the virus enzymes or virus-cell fusion, but not the integrated provirus. We report here the substrate-linked protein evolution of a tailored recombinase that recognizes an asymmetric sequence within an HIV-1 LTR. This evolved recombinase efficiently excised integrated HIV proviral DNA from the genome of infected cells. Although a long way from use in the clinic, we speculate that this type of technology might be adapted in future antiretroviral therapies, among other possible uses.     

In vitro effects of lipopolysaccharides on bovine uterine contractility

Metritis is an important disorder in dairy cows during the early postpartum period. Myometrial contractility is a prerequisite for uterine involution; however, very scanty literature is available about the effect of metritis on this process and endocrine responsiveness. This study was aimed to evaluate the effect of inflammation on uterine contractility in vitro, and the inflammation was induced by incubating myometrial strips with lipopolysaccharides (LPS). Myometrial samples were collected from 17 healthy Holstein Friesian cows during caesarean section. Eight longitudinal strips from each cow were incubated in organ baths with LPS concentrations of 0 (LPS₀), 0.1 (LPS_0.1), 1 (LPS₁) and 10 µg/ml (LPS₁₀). Spontaneous contractility and contractility induced by increasing concentrations of oxytocin (10^–10 – 10^–7 mol/L) were recorded during nine 30-min intervals (T1 to T9). The minimum amplitude (minA), maximum amplitude (maxA), mean amplitude (meanA) and area under the curve (AUC) were calculated for each time interval. LPS had an effect (p ≤ .05) on maxA, meanA and AUC. In T1, myometrial strips incubated with LPS_0.1 and LPS₁ had higher (p ≤ .05) maxA, meanA and AUC than the strips incubated with LPS₀. In T9 without oxytocin, LPS₀ led to higher (p ≤ .05) maxA, meanA and AUC than LPS_0.1 and LPS₁. In T8 and T9 with oxytocin, LPS₁ had lower (p ≤ .05) maxA, meanA and AUC than the other LPS concentrations. Interestingly, the results show that LPS has a transient positive effect on myometrial contractility in vitro and that this effect is dependent on LPS concentration and duration of incubation.     

Schätzung des Humusgehaltes nach der Munsell-Farbhelligkeit

Calculation of the humus content of soil samples by the Munsell-value The log values of humus contents (0.1–15%) and the Munsell-values of 156 dry or moist soil samples from Northern Germany were strongly correlated, especially in additional consideration of Munsell-chromas and soil texture.     

Der Einsatz von Kationenaustauscherharzen zur Charakterisierung verfügbarer Kationen aus natürlich gelagerten Bodenproben

Investigation of cation release of undisturbed soil columns via cation exchange resins Undisturbed soil columns were investigated with cation exchange resins. Similar to roots there is an exchange of H⁺ and cations. The ability for release of cations by molecular diffusion is decreasing with time, so that an asymptotic approximation to a final value occurs. A part of the protons is buffered, for example by aluminium-hydroxides. Samples rich in organic carbon show different graphs for iron and manganese which is probably due to microbial reduction processes.     

Bacterial ghost technology for pesticide delivery

Bacterial ghosts are nondenaturated empty cell envelopes of Gram-negative bacteria produced by E-mediated lysis. Such envelopes from the plant-adhering bacterium Pectobacterium cypripedii were tested for their ability to adhere to plant material and to be used as carriers for pesticide delivery. We show, using fluorescence-labeled P. cypripedii ghosts, that depending on the target plants 55 or 10% (rice or soya, respectively) of the applied bacterial ghosts was retained on the leaves after heavy simulated rain (84 mm). Furthermore, the bacterial ghosts could be loaded with the lipophilic triazole fungicide tebuconazole. In subsequent plant experiments in the glass house, the efficacy of the loaded bacterial ghost for resistance to rainfall and the protective and curative effects against the pathogens Erysiphe graminis, Leptosphaeria nodorum, and Pyrenophora teres on barley and wheat and against Sphaerotheca fuliginea on cucumber were tested. The bacterial ghosts were compared primarily with a commercial tebuconazole formulation, a wettable powder, as it has similar physical characteristics. The comparison revealed similar effects and showed consistently higher or comparable efficacy against the pathogens. The standard operational comparison with the most protective, cereal specific emulsion of oil in water displayed that the bacterial ghosts had equal to or lower efficacy than the emulsion. This study confirmed the potential of bacterial ghost platform technology as a new alternative carrier system for pesticides.     

Role of riboflavin in beer flavor instability: determination of levels of riboflavin and its origin in beer by fluorometric apoprotein titration

A method for the quantitative determination of riboflavin levels in beer was developed. The method is based on the quenching of riboflavin fluorescence, which occurs when riboflavin binds to the aporiboflavin-binding protein from egg white. The method does not require any pretreatment of the beer before analysis, other than dilution, and proved to be simple, reliable, and sensitive. The lowest concentration that could be detected was approximately 10 nM riboflavin. The possible interference of flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) with the determination of the riboflavin content of beer was excluded, because beer contains only a very small amount of FAD (0.03 microM) and no FMN. The riboflavin levels of the types and brands of beer investigated were in the range of 0.5-1.0 microM. The origin of the riboflavin in beer proved to be the malt. Hop and yeast hardly contributed to the riboflavin content of beer. Besides its use in the determination of riboflavin levels, the aporiboflavin-binding protein also provides a way to remove riboflavin from beer, which reduces the light sensitivity and the related lightstruck off-flavor formation in beer.     

Metabolic profiles of the mycotoxin zearalenone and of the growth promoter zeranol in urine,liver, and muscle of heifers

A group of five heifers were fed for 84 days with 2 kg of zearalenone-contaminated oats (1370 microg/kg) resulting in an average daily intake of 2740 microg of zearalenone per animal. In a parallel experiment five heifers were implanted with two 25 mg zeranol pellets, one at the beginning of the study and one after 42 days, and fed with 2 kg of "blank" control oats (79 microg/kg, daily intake = 158 microg). A third group of five animals were also fed with 2 kg of "blank" oats and served as control. Urine samples of all animals were collected every 5-6 days during the whole period of the study. Animals of all three groups were killed 84 days after the beginning of the feeding study. Tissue samples (back, femoral region, liver, and residues of implanted pellets) were taken during post-mortem investigations. The content of zearalenone and zeranol and their metabolites in urine and tissue samples was established by an analytical method combining solid-phase extraction and high-performance liquid chromatography-tandem mass spectrometry. Urinary excretion rates of zeralenone and zeranol were calculated from these results.     

Humus balances of different farm production systems in main production areas in Austria

The importance of the soil humus content is indisputable. Soil humus plays an important role in preserving soil fertility and exerts great influence on plant production and yield potential. However, proofing that management‐related changes in the stock of soil organic matter (SOM) have taken place against the background of spatial and temporal variation is a difficult task. In most cases, sampling over a long period of time is needed to verify these changes. Alternatively, potential changes in the SOM stock can be estimated using humus balancing models, which help to identify the need for humus reproduction on a farm. In general, a humus balance is the difference between the humus demand of cultivated crops and humus supply through crops and organic fertilizers. In this study, the ‘Dynamic Humus Unit Method' within the modelling program REPRO was applied to calculate the humus balance for 29 model‐farms that are representative of most of the agricultural production in Austria. Each model‐farm represents a specific production type (PT) and farming system in a defined region or main production area (MPA). This approach gives an overview of the humus balances at a large scale and allows a general trend in Austria to be estimated. Besides differing between conventional and organic farming systems, specific site conditions can also be selected in the model. The constructed model‐farms belong to different PTs such as “forage production”, “cash crops”, “refinement”, and “permanent crops”. The PT “permanent crops” refers to the cultivation of wine. The cropping system of each PT was analyzed in detail, while livestock keeping was considered only when applicable. Positive humus balances were found for all PTs except for permanent crops. The results ranged from –122 to 890 kg C ha^?1 y^?1. Regions and farm structure, e.g., forage production compared to cash crop, were found to have a greater influence than the kind of farming system (i.e., organic vs. conventional farming). Comparing the different PTs, forage production had the highest positive humus balances (219 to 890 kg C ha^?1 y^?1), followed by cash crop (24 to 239 kg C ha^?1 y^?1), refinement (–64 to 402 kg C ha^?1 y^?1) and permanent crops (–122 to –38 kg C ha^?1 y^?1). Regarding the farming system, organic farming led to more humus accumulation than conventional farming due to a higher share of fodder legumes and catch crops and more diverse crop rotations. The results were within the range of available empirical data on SOM change, and it was therefore concluded that the results are reasonable. In general, humus reproduction can be regarded as sufficient for agricultural production.     

Time pattern analysis of swimming activity and heart rate under the influence of chloramphenicol in carp (Cyprinus carpio L.) and rainbow trout (Salmo gairdneri R.)

In industrial fish production there is little information available about the effect of antibiotics on the fish organism. The swimming activity of carp and trout before, during and after treatment with chloramphenicol was observed. Due to the daily rhythmical organization of body function and closely correlated periods of activity and rest, a treatment with chloramphenicol at different times of the day has different effects on swimming activity. A significant increase in heart rate after treatment with chloramphenicol was detected as compared to the controls. These results suggest that treatment with chloramphenicol should be given during the last feeding.