Plankton adaptation to warmer oceans.

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Phytoplankton carry out around half of all photosynthesis on Earth. They lower CO2 concentrations in the oceans, add oxygen to our atmosphere, and are the basis of most ocean and many freshwater food chains. When they die, phytoplanktons also sequester carbon in the deep ocean as they sink towards the ocean floor. The organisms’ close relationship with CO2 and the carbon cycle means that climate change scientists need to understand how global warming will alter phytoplankton populations. Additionally, ecologists wish to understand phytoplankton to predict the oceans’ future health.

Water temperatures significantly affect the limits of phytoplankton growth rates: populations near the equator have the potential to grow much faster than strains found in cooler waters, near the poles, given sufficient nutrients. The researchers of this study believe that current models underestimate the effects of rising temperatures on ocean ecosystems. Such models focus on indirect mechanisms, such as how rising temperatures lead to fewer nutrients in surface ocean waters. This study therefore investigated the direct effect of higher temperatures on individual phytoplankton species.

The scientists used an eco-evolutionary model to investigate how phytoplankton adapts to current ocean temperatures. They also used species distribution models, to predict how ocean temperature changes would affect populations.

The results suggest that by the end of the 21st century, warmer oceans will lead to a greater diversity of plankton populations nearer the poles, but fewer varieties in warmer, tropical waters at the equator. Even though marine organisms can disperse over long distances carried by ocean currents, each plankton strain grows best at an optimum temperature and adapts to its local environment. Tropical strains appear to be most vulnerable to rising temperatures. The researchers predict that around a third of current strains in the tropics would become extinct by 2100 if mean temperatures increase by just 2°C. However, high genetic diversity within species may prevent the loss of entire species.

Rising temperatures will thus affect phytoplankton in different ways, depending on their location. Until we learn more about how phytoplankton evolves, there is significant uncertainty regarding how these organisms will respond to climate change and to what extent we can rely upon them to remove CO2 from our atmosphere. The future health of the ocean ecosystems that depend on them is also threatened.

Source: European Commission News Alert: Science for Environment Policy

Thomas, M.K., Kremer, C.T., Klausmeier, C.A., and Litchman, E. (2012) A Global Pattern of Thermal Adaptation in Marine Phytoplankton. Science. 338: 1085-1088.

Determination of OA-toxins by a phosphatase inhibition assay. Collaborative study.

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Just published the collaborative study on OkaTest, colorimetric phophatase inhibition assay for OA-toxins. Smienk et al, 2013, J. AOAC International. 96, 1, 77-85. Smienk.et al.2013, JAOAC, 96,1,77-85 Abstract A collaborative study to validate a colorimetric phosphatase inhibition assay for quantitative determination of the okadaic acid (OA) toxins group in molluscs, OkaTest, was conducted. Eight test materials including mussels, scallops, clams and cockles were analysed as blind duplicates. Blank samples and materials containing different OA-toxin levels ranging from 98 to 275 µg/kg OA equivalents were included. The study was carried out by a total of 16 laboratories from 11 different countries. Values obtained for repeatability relative standard deviations (RSDr) ranged from 5.4% to 11.2% (mean 7.5%). Reproducibility relative standard deviation (RSDR) values were between 7.6% and 13.2% (mean 9.9%). The HORRAT values ranged between 0.4 and 0.6. A recovery assay was also carried out using a sample spiked with OA. A mean recovery of 98.0% and a relative standard deviation of 14.5% were obtained. The results obtained in this validation study indicate that the colorimetric phosphatase inhibition assay, OkaTest, is suitable for the quantitative determination of the OA-toxins group. OkaTest could be used as a complementary test to the reference method for monitoring the OA-toxin group. Details of the test materials, number of results submitted and results after removing outliers, together with performance values of precision (repeatability and reproducibility) obtained for the colorimetric OkaTest. Sr: Repeatability standard deviation. SR: Reproducibility standard deviation. RSDr: Repeatability relative standard deviation. RSDR: Reproducibility relative standard deviation.  r: Repeatability Limit, R: Reproducibility Limit.

Cheese celebrates his 9.000th birthday

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Humans have been eating cheese for 9.000 years. A group of researchers from UK, USA and Poland has proved that people ate cheese back in 7.000 B.C. Several pieces of pottery with holes similar to actual cheese strainers have been found in multiple sites from Anatolia, Europe and Africa. Scientists have found a great amount of milk fats inside strainers holes. So these specialized pottery vessels were used to milk processing without doubt. According to these evidences, farmers from Neolithic period did an early use of milk, separating fat-rich milk cruds from lactose-containing whey. The processing of milk could have been a relevant development in prehistoric agriculture not only allowing the preservation of milk, but also manufacturing milk derivates with less lactose more easily to digest.

Salque M., et al. Nature. 2013 Jan 24;493(7433):522-5. doi: 10.1038/nature11698

NEW IC BUFFALO KIT: Detection of cow’s milk in buffalo’s milk.

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The unknown mixture of milk from different species is a common fraud in the cheese sector. The different prices of milk species tends to adulterate the expensive with those of lower cost. This adulteration is especially important for cheese makers, not only for economical reasons, but also because unknown milk mixtures produce changes in the final sensory properties and reduce the product quality. Besides, cheese producers need to assure that pure cheese does not contain milk from other species for labelling purposes.

The fraudulent addition of cow´s milk during the manufacturing of water buffalo Mozzarella cheese has increased in recent years, due to the growing market demands in EU (European Union). Mozzarella cheese is registered with Protected Designation of Origin (PDO) that demands it only can be made from water buffalo´s milk. Finally, the European Regulations concerning cheeses from different species milk, buffalo included, demand to verify by appropriate controls that no cow´s milk has been incorporated.

The NEW IC BUFFALO is a qualitative test to detect the presence of cow’s milk in buffalo´s milk. The kit is an immunochromatography test based on the detection of bovine immunoglobulins (IgG) in milk samples. This test can be used with fresh, pasteurised, whole or skim milk. The IC BUFFALO kit does not require any technical skills or lab equipment and can allow cheese producers to make fast decisions, which can save them money and ensure the quality of the final product.

ZEU-INMUNOTEC offers other rapid screening test kits to identify the presence of cow’s milk in sheep and goat milk (IC-Bovino), or alternatively to detect goat’s milk in cow’s (IC-Caprino). ELISA tests (RC-Bovino and RC-Caprino) are also available for quantification of the milk mixture.

 

Celiac patients would improve their quality life.

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Chinese, German and north American researchers has been able to produce what varieties compatible for celiac patients. Gluten is a complex mixture of several proteins known as gliadins. In a single bread wheat variety is comprised of up to 45 different gliadins. Some of these proteins induce an autoimmune reaction in celiac patients. The only effective therapy is strict dietary abstinence from food with gluten, but is quite difficult to comply with. Besides, following a gluten-free diet has adverse influence on gut microbiota causing digestive problems. In this work, researches have been avoiding the expression of the enzyme that controls the synthesis of some gliadins. These wheat varieties showed a 76.4% reduction in celiac response gliadins. It is has claim that these modified wheat would be able to bake food suitable for celiac patients. In addition patients would allow consume non immunogenic gluten avoiding adverse effects of a gluten free diet. Original source: Wen, S. et al. Proc Natl Acad Sci USA. 2012 Dec 11;109(50):20543-8. doi: 10.1073/pnas.1217927109.