The HIV-1 Tat protein stimulates viral gene expression by recruiting human transcription elongation complexes containing P-TEFb, AFF4, ELL2, and ENL or AF9 to the viral promoter, but the molecular organization of these complexes remains unknown. To establish the overall architecture of the HIV-1 Tat elongation complex, we mapped the binding sites that mediate complex assembly in vitro and in vivo. The AFF4 protein emerges as the central scaffold that recruits other factors through direct interactions with short hydrophobic regions along its structurally disordered axis. Direct binding partners CycT1, ELL2, and ENL or AF9 act as bridging components that link this complex to two major elongation factors, P-TEFb and the PAF complex. The unique scaffolding properties of AFF4 allow dynamic and flexible assembly of multiple elongation factors and connect the components not only to each other but also to a larger network of transcriptional regulators.paused RNA polymerase II | intrinsically disordered proteins | super elongation complex | MLL-fusion complex R NA polymerase II (Pol II) activity is tightly regulated throughout the steps of eukaryotic transcription. Each stage-initiation, clearance from the promoter, elongation, and termination-is licensed by specific factors that serve as checkpoints (1-4). Pol II transcription downstream of the promoter also involves intricate crosstalk between elongation and posttranscriptional events, such as splicing (5-7).

The aim of the study was to evaluate the effect of nitrogen (N) and sulphur (S) fertilizer on grain yield of spring wheat and its technological quality. A field experiment (2009-2011) was conducted in south-eastern Poland on Cambisols. The experiment included 2 factors: N fertilization (0, 40, 80, 120 kg/ha) and S fertilization (0, 50 kg/ha). The experiment showed that spring wheat cv. Tybalt exhibited a positive reaction of N and S fertilization on grain yield, which was the highest at the application of 80 kg N/ha (5.40 t/ha), increasing by 1.30 t/ha (13.1%) with respect to the control. S fertilization increased grain yield by 3.58%. S application increased significantly the content of gluten by 3.2%, cysteine by 6.0% and methionine by 16.5%. The most beneficial effect on the content of N, S, total protein, gluten, cysteine and methionine was observed for N application a rate of 80 kg/ha and for S at a rate of 50 kg/ha. Positive correlation was found between the content of S in grain and grain yield (r = 0.73). Significant correlations were found also between grain yield and all other quality characteristics except for N and starch content.

SummarySuccinic acid is an important C4‐building chemical platform for many applications. A novel succinic acid‐producing bacterial strain was isolated from goat rumen. Phylogenetic analysis based on the 16S rRNA sequence and physiological analysis indicated that the strain belongs to the genus Enterobacter. This is the first report of a wild bacterial strain from the genus Enterobacter that is capable of efficient succinic acid production. Co‐fermentation of glycerol and lactose significantly improved glycerol utilization under anaerobic conditions, debottlenecking the utilization pathway of this valuable biodiesel waste product. Succinic acid production reached 35 g l−1 when Enterobacter sp. LU1 was cultured in medium containing 50 g l−1 of glycerol and 25 g l−1 of lactose as carbon sources.

The study concerns the measurement of the technical efficiency of agriculture in the 27 European Union (EU) countries in 2010. The studies were conducted based on the result-oriented DEA method assuming variable advantages of scale. Moreover, in the study, the factors affecting technical efficiency were identified, and the econometric modelling of their impact was performed with the use of the Tobit model. The studies indicate that across the 27 EU Member States, the level of the technical efficiency of agriculture is diverse, and the difference between the states with the highest and the lowest efficiencies is 40%. Cyprus, Denmark, Greece, France, Spain, the Netherlands, Luxembourg, Italy and Malta were identified as the countries with the thoroughly technically efficient agriculture. In turn, the least technically efficient agriculture is observed for the Czech Republic, Lithuania, Hungary, Ireland, Latvia and Slovakia. Taking into account the factors determining the technical agriculture efficiency, it should be noted that the stimulants have proven to be such factors as: the soil quality, the age of the head of the household and the surcharges for investments. In turn, the size of the farm appeared to be irrelevant from the viewpoint of the technical efficiency of the agricultural sector.

SUMMARYAlthough the effect of saponins or saponin-containing plants on rumen microorganisms and rumen fermentation has been intensively investigated, this issue still requires special attention. Many of the phenomena occurring in the rumen related to dietary saponin supplementation are still not fully understood. Saponaria officinalis is a triterpenoid saponin-containing plant; thus, the aim of the present study was to evaluate the effect of S. officinalis L. powdered root, methanolic extract of the S. officinalis root (SOR) and the effect of the separated fractions (polysaccharides, saponins and phenolics) of S. officinalis on rumen methanogenesis, microbial population and rumen fermentation characteristics in an in vitro batch culture fermentation system. The powdered root (raw plant material) and S. officinalis extract (SOE) decreased in vitro methane production and consequently reduced the microbial population in a dose-dependent manner. The inhibition of methanogenesis was accompanied by changes in the volatile fatty acids profile. In vitro dry matter digestibility was not affected by any of the secondary compounds applied. The highest applied doses of SOE caused a higher reduction in methanogenesis (33·5 v. 14·4%) than the highest doses of powdered root form. Such results suggest that the basic components of the SOR could interact with phytochemicals or that the phytochemicals became physically less available for microbiota, resulting in a decreased antimethanogenic activity of the powdered root v. the extract. Among all the fractions selected, the saponin fraction exerted the greatest impact on ruminal fermentation. In conclusion, saponins decreased methane production by 29% in comparison with the control. This decrease was related to the reduction in protozoa and methanogen counts. It is proposed that S. officinalis has the potential to inhibit rumen methanogenesis without affecting rumen fermentation adversely.

This study measures changes in total factor productivity of agriculture for 25 European Union (EU) member states in 2004–2016 using the Färe-Primont index. It also attempts to answer the question whether in the analysed period the levels of total factor productivity in this sector were convergent between member states. To this end, panel unit root tests were used. The study indicates that in new EU member states the level of total factor productivity (TFP) was relatively lower than in most EU-15 states. It was also found that convergence occurred in agricultural productivity almost in all EU member states (except Belgium and the United Kingdom). The research shows that in new EU member states the process of making up differences in the productivity of agriculture was stronger than in old EU member states.

An increase in the area under soybean and other legume crops in Europe is one of the assumptions of the European Soya Declaration. A study was undertaken to evaluate the influence of cropping system and tillage system on yield, some quality characteristics of soybean seeds and economic evaluation. Therefore, this paper is of interdisciplinary nature. On average over a four-year study period, the soybean seed yield was significantly higher in monoculture compared to the yield obtained in crop rotation. A decreasing trend in yield of monocultured soybean was only observed in the 4th year of the experiment. Seeds grown in monoculture were characterized by a significantly higher percentage protein content and a lower fat content compared to obtained in crop rotation. Plough tillage affected more beneficially soybean yield. Under no-tillage conditions, soybean seeds were shown to have a higher percentage protein content and a lower fat content. The average income per ha of soybean grown under plough tillage system was higher by EUR 64.6 than that under no-tillage. In comparing production profitability depending on the cropping system, it can be noted that it was more beneficial to grow soybean in monoculture. In monoculture, both plough tillage and no-tillage generated a higher income per ha than in the case of soybean grown in crop rotation.

Enterobacter aerogenes LU2 was isolated from cow rumen and recognized as a potential succinic acid producer in our previous study. Here, we present the first complete genome sequence of this new, wild strain and report its basic genetic features from a biotechnological perspective. The MinION singlemolecule nanopore sequencer supported by the Illumina MiSeq platform yielded a circular 5,062,651 bp chromosome with a GC content of 55% that lacked plasmids. A total of 4,986 genes, including 4,741 protein-coding genes, 22 rRNA-, 86 tRNA-, and 10 ncRNA-encoding genes and 127 pseudogenes, were predicted. The genome features of the studied strain and other Enterobacteriaceae strains were compared. Functional studies on the genome content, metabolic pathways, growth, and carbon transport and utilization were performed. The genomic analysis indicates that succinic acid can be produced by the LU2 strain through the reductive branch of the tricarboxylic acid cycle (TCA) and the glyoxylate pathway. Antibiotic resistance genes were determined, and the potential for bacteriocin production was verified. Furthermore, one intact prophage region of length ~31,9 kb, 47 genomic islands (GIs) and many insertion sequences (ISs) as well as tandem repeats (TRs) were identified. No clustered regularly interspaced short palindromic repeats (CRISPRs) were found. Finally, comparative genome analysis with well-known succinic acid producers was conducted. The genome sequence illustrates that the LU2 strain has several desirable traits, which confirm its potential to be a highly efficient platform for the production of bulk chemicals. Enterobacter aerogenes LU2 is a gram-negative, wild bacterium that was isolated from cow rumen as a part of environmental screening for succinic acid-producing bacteria identification. Succinic acid (SA) plays an important role as a metabolic intermediate in the rumen by increasing propionate production, a crucial energy source for the ruminant 1,2. Anaerobic conditions and the presence of carbon dioxide, methane and trace amounts of hydrogen create an excellent environment for the biosynthesis of succinate by some bacteria existing in the rumen 3. In reports of the U.S. Department of Energy (DOE) from 2004 and 2010, SA was recognized as one of the top 10 most promising C4-building chemical platforms for the production of high-value commodity and specialty chemicals with great industrial potential 2,4. Succinate is widely applied as an additive in food, pharmaceuticals, detergents, solvents, and surfactants as well as in biodegradable polymer production 5,6. Until recently, industrial production of succinate was based on chemical synthesis. However, petroleum-based production of SA from n-butane through maleic anhydrate requires the use of high pressure, high temperature and costly catalysts 7. Therefore, because of the current global trend regarding sustainable development, including the support of green technologies, rational waste biomass management and pollution-reducing standards, the bio-based production of...