Arresting cell growth and thus decreasing cell division potentially lessens the chance for genetic drift in the cell population; this would be of utmost importance for the consistent production of biopharmaceuticals during long periods. The drawback of the addition of well-known synchronizing agents, such as chemotherapeutics, is that they cause a disproportionate accumulation of cellular constituents, leading to cell death. The use of compounds that are naturally synthesized by the cell, as is the case of nucleotides, nucleosides, and bases (Nt/Ns/B), is shown in this work to be a promising tool. The addition of purines and pyrimidines was tested using a CHO cell line producing the secreted form of the human placental alkaline phosphatase enzyme (SEAP). From the chemical alternatives tested, AMP was the most promising compound for protein production improvement; it reduced cell growth and maintained the culture with high cell viability for long periods, while increasing SEAP specific productivity 3-fold. The use of CHO and BHK mammalian cells producing Factor VII and the use of a insect cell line (Sf9) showed that the effect of AMP addition seems to be independent of the r-protein and cell line. With the addition of AMP, accumulation of cells at the S phase was accompanied by an increase of the protein specific productivity. Addition of known synchronizing drugs (aphidicolin and doxorubicin) and application of environmental cell growth arrest strategies (depletion of nutrients and byproduct accumulation) showed also to effectively arrest CHO cell growth. A careful look onto cell cycle distribution in the different scenarios created, shows whether it is important to consider r-protein expression dependency upon cell cycle in process optimization and operation strategies.

Dryland pastures in the Alentejo region, located in the south of Portugal, normally occupy soils that have low fertility but, simultaneously, important spatial variability. Rational application of fertilizers requires knowledge of spatial variability of soil characteristics and crop response, which reinforces the interest of technologies that facilitates the identification of homogeneous management zones (HMZ). In this work, a pasture field of about 25 ha, integrated in the Montado mixed ecosystem (agro-silvo-pastoral), was monitored. Surveys of apparent soil electrical conductivity (ECa) were carried out in November 2017 and October 2018 with a Veris 2000 XA contact sensor. A total of 24 sampling points (30 × 30 m) were established in tree-free zones to allow readings of normalized difference vegetation index (NDVI) and normalized difference water index (NDWI). Historical time series of these indices were obtained from satellite imagery (Sentinel-2) in winter and spring 2017 and 2018. Three zones with different potential productivity were defined based on the results obtained in terms of spatial variability and temporal stability of the measured parameters. These are the basis for the elaboration of differentiated prescription maps of fertilizers with variable application rate technology, taking into account the variability of soil characteristics and pasture development, contributing to the sustainability of this ecosystem.

Emergence of weed seedlings depends on soil environmental conditions; mainly temperature and moisture, with the latter being fundamental and particularly important in environments which are characterised by irregular amounts and distribution of rainfall throughout the year. Thus, this study looks at the influence of soil moisture and air temperature on the emergence of weed seedlings. The experiment was carried out under controlled environmental conditions, using rings filled with samples of undisturbed topsoil (0-2.5 cm and 0-5 cm deep) of a Luvisol. There were four moisture levels that were maintained constant, with several repetitions (16-20). The results indicate that the maximum population density of weed plants was obtained with soil moisture near field capacity. With regard to the depth of the soil containing the seeds which contributed towards optimising population density, it was noted that the first 2-3 cm of undisturbed soil were critical for maximising the population. The emergence of seedlings was modelled using data from the five centimetre topsoil with soil moisture close to field capacity. This model indicates that a mean daily temperature sum of 446 ºC, which under Mediterranean autumn conditions represent a period of approximately one month, is needed, in order to obtain 80% of potential autumnwinter plant density, relative to the observed potential.

a b s t r a c tIn general, effective weed control in no-tillage systems is based on the use of herbicides. However, the development of appropriate weed management strategies can help to reduce the amount of herbicides applied.In this study weed management in common wheat under no-till was analyzed. The experiment was carried out under Mediterranean conditions on a Luvisol, during two growing seasons (1996/1997 and 1999/2000). A split-plot design with four replications was used. The main plot was weed emergence before wheat sowing (with and without weed emergence) and the subplot was the postemergence weed control (with and without post-emergence herbicide).The density of the weeds was significantly reduced when the wheat crop was sown after a considerable part of the weeds had emerged and controlled by a presowing herbicide (non-selective, systemic and non-persistent). Without weed control in post-emergence treated plots, the number of grains and the yield was increased significantly, compared to sowing without weed emergence. It can be concluded that under Mediterranean conditions, it is possible to reduce or even avoid the application of post-emergence herbicides in wheat under no-till, as weeds can be efficiently controlled before sowing.

A study was carried out over a two year period (2009/2010 and 2012/2013) on an experimental farm in the Alentejo region (Beja), in southern Portugal where rainfed malt barley (Hordeum distichum L.) is sown at the end of autumn or beginning of winter (November- December). The aim of this experiment was to study the efficiency of the herbicide iodosulfuron-methyl-sodium to control post-emergence broadleaved weeds in this cereal crop. The malt barley crop was established using no-till farming. This technology provides the necessary machine bearing capacity of the soil to assure the post-emergence application of herbicides at two different weed development stages. The herbicide iodosulfuron-methyl-sodium was applied at three doses (5.0, 7.5, and 10.0 g a. i. · ha-1) and at two different broadleaved weed development stages (3 to 4 and 6 to 7 pairs of leaves), that also corresponded to two different crop development stages (beginning of tillering and complete tillering). The results indicated that early herbicide application timing provided a significantly higher efficiency for all the applied herbicide doses, but this better weed control was not reflected in a higher crop grain yield. The lack of a higher crop grain yield was probably due to a crop phytotoxicity of the herbicide, when used at an early application timing.