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Taxonomy: Recommendations on researching biodiversity

Taxonomy, the science of identifying, describing and classifying life forms, is currently experiencing a technological revolution. As a result, the goal of collecting data on the Earth’s entire biological diversity is becoming achievable. At the same time, the importance of taxonomy is growing in many fields, such as medicine, the food industry, and agriculture. With a view to making optimal use of the new opportunities available to taxonomy, the German National Academy of Sciences Leopoldina recommends, in its statement entitled “Challenges and Opportunities of Integrative Taxonomy for Research and Society,” promoting efforts to describe all the species of Central Europe. The statement also calls for investments in taxonomic research and teaching.

The vast majority of the Earth’s species are still unknown to us. New species are not only being discovered in rainforests and deep down in the ocean, but even right here on our doorstep, in Central Europe. In its statement “Challenges and Opportunities of Integrative Taxonomy for Research and Society,” the Leopoldina recommends setting up a research project to describe all the species in Central Europe. The authors stress that the findings of the taxonomic research should be made easily available. For example, the exact classification of microorganisms used in food production contributes to greater food security, and in future it will be possible to more accurately classify soil microbes that are important for agricultural yields.

“High throughput processes for analysing genetic information, proteins and metabolic products — so-called ‘omics’ methods — are now allowing us to conduct fast, highly accurate taxonomic analyses,” said Prof. Jörg Hacker, President of the German National Academy of Sciences Leopoldina. “We need to improve the way we harness these new possibilities for the life sciences and industry.”

“Taxonomic research in Germany has an excellent reputation worldwide. If we are to continue to pursue cutting-edge research in this important area, it must become a priority at the most capable research institutions, networking and internationalisation must be increased, and the training of young scientists in taxonomy must be improved,” said Prof. Rudolf Amann of the Max Planck Institute for Marine Microbiology in Bremen, who is spokesman of the working group.

Germany is currently considered one of the leading locations for taxonomic research. To ensure that the country can continue to produce excellent findings in taxonomy, the Leopoldina recommends making taxonomy a focus of the work at selected research locations, improving training for young taxonomists, and creating national and international networks in the field. It also calls for the establishment of a centralised infrastructure for digitising and storing taxonomic data, and recommends digitising research collections at museums and research institutes.

The English version of the statement by the German National Academy of Science Leopoldina is available at www.leopoldina.org/en/taxonomy

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The above story is based on materials provided by Leopoldina. Note: Materials may be edited for content and length.

Agriculture and Food News — ScienceDaily

Taxonomy: Recommendations on researching biodiversity

Taxonomy, the science of identifying, describing and classifying life forms, is currently experiencing a technological revolution. As a result, the goal of collecting data on the Earth’s entire biological diversity is becoming achievable. At the same time, the importance of taxonomy is growing in many fields, such as medicine, the food industry, and agriculture. With a view to making optimal use of the new opportunities available to taxonomy, the German National Academy of Sciences Leopoldina recommends, in its statement entitled “Challenges and Opportunities of Integrative Taxonomy for Research and Society,” promoting efforts to describe all the species of Central Europe. The statement also calls for investments in taxonomic research and teaching.

The vast majority of the Earth’s species are still unknown to us. New species are not only being discovered in rainforests and deep down in the ocean, but even right here on our doorstep, in Central Europe. In its statement “Challenges and Opportunities of Integrative Taxonomy for Research and Society,” the Leopoldina recommends setting up a research project to describe all the species in Central Europe. The authors stress that the findings of the taxonomic research should be made easily available. For example, the exact classification of microorganisms used in food production contributes to greater food security, and in future it will be possible to more accurately classify soil microbes that are important for agricultural yields.

“High throughput processes for analysing genetic information, proteins and metabolic products — so-called ‘omics’ methods — are now allowing us to conduct fast, highly accurate taxonomic analyses,” said Prof. Jörg Hacker, President of the German National Academy of Sciences Leopoldina. “We need to improve the way we harness these new possibilities for the life sciences and industry.”

“Taxonomic research in Germany has an excellent reputation worldwide. If we are to continue to pursue cutting-edge research in this important area, it must become a priority at the most capable research institutions, networking and internationalisation must be increased, and the training of young scientists in taxonomy must be improved,” said Prof. Rudolf Amann of the Max Planck Institute for Marine Microbiology in Bremen, who is spokesman of the working group.

Germany is currently considered one of the leading locations for taxonomic research. To ensure that the country can continue to produce excellent findings in taxonomy, the Leopoldina recommends making taxonomy a focus of the work at selected research locations, improving training for young taxonomists, and creating national and international networks in the field. It also calls for the establishment of a centralised infrastructure for digitising and storing taxonomic data, and recommends digitising research collections at museums and research institutes.

The English version of the statement by the German National Academy of Science Leopoldina is available at www.leopoldina.org/en/taxonomy

Story Source:

The above story is based on materials provided by Leopoldina. Note: Materials may be edited for content and length.

Agriculture and Food News — ScienceDaily

Bee biodiversity boosts crop yields

Research from North Carolina State University shows that blueberries produce more seeds and larger berries if they are visited by more diverse bee species, allowing farmers to harvest significantly more pounds of fruit per acre.

“We wanted to understand the functional role of diversity,” says Dr. Hannah Burrack, an associate professor of entomology at NC State and co-author of a paper on the research. “And we found that there is a quantifiable benefit of having a lot of different types of bees pollinating a crop.”

The researchers looked at blueberries in North Carolina because it is an economically important and well understood crop that relies on insect pollination.

Within the blueberry fields, the researchers identified five distinct groups of bee species: honey bees, bumble bees, southeastern blueberry bees, carpenter bees and a functionally similar collection of species that they termed small native bees.

The researchers found that for each group above one, farmers saw an increase of $ 311 worth of yield per acre. For example, if two bee groups pollinated a field, the boost would be $ 311 per acre; for three bee groups, the boost would be $ 622 per acre, and so on.

“For North Carolina blueberries as a whole, we calculate the benefit of each group to be approximately $ 1.42 million worth of yield each year,” Burrack says.

“We think the benefit stems from differences in behavior between bee groups, in part depending on the weather,” explains Dr. David Tarpy, an associate professor of entomology at NC State and co-author of the paper. For example, southeastern blueberry bees work well regardless of inclement weather, whereas honey bees only perform at their best on calm, warm, sunny days.

“This can make a big difference, since blueberries bloom in March and April in North Carolina,” Burrack says. “That means the weather can swing from great to awful, as we saw this year.”

There is some research showing that having native, flowering plants near blueberry fields can increase native bee populations over time, but the researchers are now planning to see what role crop management can play in fostering bee diversity at crop sites.

“We’ve shown that there is a real financial benefit associated with biodiversity,” Burrack says. “The next step is to figure out how to foster that diversity in practical terms.”

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The above story is based on materials provided by North Carolina State University. Note: Materials may be edited for content and length.

Agriculture and Food News — ScienceDaily

In grasslands remade by humans, animals may protect biodiversity: Grazers let in the light, rescue imperiled plants

A comparative study of grasslands on six continents suggests there may be a way to counteract the human-made overdose of fertilizer that threatens to permanently alter the biodiversity of the world’s native prairies.

The solution is one that nature devised: let grazing animals crop the excess growth of fast growing grasses that can out-compete native plants in an over-fertilized world. And grazing works in a way that is also natural and simple. The herbivores, or grazing and browsing animals, feed on tall grasses that block sunlight from reaching the ground, making the light available to other plants.

That’s the key finding of a five-year study carried out at 40 different sites around the world and scheduled for online publication March 9, 2014 in the journal Nature. More than 50 scientists belonging to the Nutrient Network, a team of scientists studying grasslands worldwide, co-authored the study.

“This study has tremendous significance because human activities are changing grasslands everywhere,” said study co-author Daniel S. Gruner, associate professor of entomology at the University of Maryland. “We’re over-fertilizing them, and we’re adding and subtracting herbivores. We have a worldwide experiment going on, but it’s completely uncontrolled.”

Gruner, a member of the Nutrient Network (which participants have nicknamed NutNet) since its founding in 2006, helped plan the worldwide study and analyze its results. Elizabeth Borer of the University of Minnesota was the study’s lead author.

The U.N. Food and Agricultural Organization estimates that grasslands cover between one-fifth and two-fifths of the planet’s land area and are home to more than one-tenth of humankind. But like all plant communities, grasslands are suffering from too much fertilizer.

As humans burn fossil fuels, dose crops with chemical fertilizers, and dispose of manure from livestock, they introduce extra nitrogen and other nutrients into the soil, air and water. The excess is a special problem for grasslands, where many plants, like annual wildflowers and others, have adapted to low nutrient levels. They often struggle to compete against grasses that use the extra nutrients to grow faster and bigger.

At the same time, grasslands worldwide are being converted to pastures for domestic animals, with native grazers like elk and antelope giving way to cattle and sheep.

Ecological theory asserts that grazers can counteract the effects of over-fertilizing in most cases, but the theory has never been broadly tested, Gruner said. To do that, the NutNet scientists ran essentially the same experiment worldwide, marking off test plots in groups of four at each of 40 sites. In each group, one plot was fenced to keep grazing animals out. One was treated with a set dose of fertilizers, to mimic the effect of excess nutrients from human sources, but was not fenced so the animals could graze. One was both fenced and fertilized. And one was left alone.

The researchers did not try to alter the test sites’ animal populations. In some places native animals were abundant. At others they’d been mostly replaced by domestic animals like cattle, goats and sheep. And still others were former pastures where livestock had browsed in the past, but were no longer there.

In general, where fertilizer was added and grazing animals were kept out, the variety of plants in the experimental plots decreased. Where animals were allowed to graze in the fertilized plots, plant diversity generally increased. The researchers’ data analysis concluded that the grazers improved biodiversity by increasing the amount of light reaching ground level.

Grassland plants have evolved a variety of strategies to take advantage of a setting where nutrients are in short supply and inconsistently available. They may be ground-hugging, or ephemeral, or shoot up when they capture a nutrient pulse, Gruner explained. These differing strategies create a diverse grassland ecosystem.

In the human-altered world where nutrients are always plentiful, plants that put their effort into growing tall to capture sunlight have an advantage. They block the sunlight from reaching most other plant species, which cannot grow or reproduce. But grazing animals cut down the light-blocking plants and give the others a chance to bloom.

“Where we see a change in light, we see a change in diversity,” said Borer, the lead author. “Our work suggests that two factors which humans have changed globally, grazing and fertilization, can control ground-level light. Light appears to be very important in maintaining or losing biodiversity in grasslands.”

The effect was greatest where large animals, wild and domesticated, grazed on the test plots: cattle, pronghorn and elk on North America’s Great Plains; wildebeests and impala on Africa’s Serengeti; and horses, sheep and ibex in rural India. In places where the only grazers were small animals like rabbits, voles and gophers, the grazers’ effect was weak and variable.

Agriculture and Food News — ScienceDaily

New plant species a microcosm of biodiversity

Biologists working in the Andes mountains of Ecuador have described a new plant species, a wild relative of black pepper, that is in itself a mini biodiversity hotspot. The new species, Piper kelleyi, is the sole home of an estimated 40-50 insect species, most of which are entirely dependent on this plant species for survival. This discovery is part of a larger project which focuses on the influence of plant-produced chemical compounds on biodiversity.

The study was published in the open access journal PhytoKeys.

The chemical compounds produced by plants are source of plants’ unique flavors, aromas, and colors. What’s less appreciated is that these compounds often have important medicinal or toxic properties, and are the plant’s natural way to resist pesky herbivores. Black pepper and its wild relatives produce a wide diversity of chemical compounds, many of which are known to be biologically active (in fact, several compounds from the new species are currently under evaluation, and show promise as possible anti-cancer drugs). These compounds are known to deter most herbivores, but a certain group of caterpillars has been able to overcome their toxicity and, as a result, most species of the genus feed only on a single species of wild black pepper. To make matters more complex, each of these caterpillars typically has one to several predatory wasp and/or fly species that attack only that caterpillar species.

Our team of scientists has made nearly 30,000 observations of over 100 black pepper relatives over 20+ years, and the new plant species described here supports the largest number of specialized caterpillar and predator species recorded for species in the black pepper family to date. Many of these insect species were discovered as a result of our investigations and are new to science (many remain unnamed). Piper kelleyi supports an estimated 40-50 species of specialized herbivores and predators, which makes this newly described plant species, in itself, a veritable biodiversity hotspot. Are there any vertebrate species that depend on this plant? Nobody knows, but relatives of black pepper are often important food sources for vertebrates, such as bats and birds, that specialize on their fruits or feed on associated insects.

This finding has conservation implications as well. The insect species that make up this unusually large assemblage are, for the most part, entirely dependent on the new plant species and, if the plant were to disappear, all of its associated animal species would too.

Evidence suggests that the unique compounds produced by a plant species, or the unique combination of these compounds, help drive the evolution of biological diversity, not only among the herbivores that feed directly on the plants, but among higher trophic levels as well. The discovery of our new species, along with its large cohort of dependent insects, lends considerable support to the hypothesis that a suite of new species of herbivores and predators of those herbivores evolves in response to the evolution of novel plant-produced chemical compounds.

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The above story is based on materials provided by Pensoft Publishers. The original story is licensed under a Creative Commons License. Note: Materials may be edited for content and length.

Agriculture and Food News — ScienceDaily

Loss of biodiversity limits toxin degradation

Jan. 16, 2014 — You might not think of microbes when you consider biodiversity, but it turns out that even a moderate loss of less than 5% of soil microbes may compromise some key ecosystem functions and could lead to lower degradation of toxins in the environment.

Research published today in the SfAM journal, Environmental Microbiology, reports that without a rich diversity of soil bacteria, specialized functions such as the removal of pesticide residues are not as effective.

Dr Brajesh Singh of the University of Western Sydney led the work, he said “If the ability of the ecosystem to remove toxins from the environment is reduced, there will be higher toxicity risks in the environment and for non-target organisms, including humans, from agricultural chemicals. It is likely that these contaminants will remain at higher levels in surface and underground water, as well. It is vital to gain a better understanding of the extent to which soil bacteria are involved in the removal of contaminants.”

The reasons for, and extent of, the decline in microbial diversity in agricultural soils is likely to be complex. The team has looked specifically at long-term heavy metal pollution where metals such as cadmium, zinc, and copper build up in the environment, usually as a result of industrial use. Another source is from digested sewage sludge, which is spread in agriculture fields to supply nutrients to crops and improve soil fertility; the sludge has historically contained some heavy metals, which can become concentrated in the soil.

Although the concentration of heavy metal used this study was higher than the current EU limit, this study has confirmed that long-term exposure to such contaminants does reduce the diversity of bacteria in the soil.

With the global population set to reach nine billion by 2050, we face a challenge to feed an extra two billion mouths using the same resources that we have at present. Crop losses to pests and disease account for a large percentage of under-production and so giving up pesticides will be difficult. Similarly, the use of sludge as a fertilizer is likely to become more prevalent. Research like this allows us to understand better how to use important agrichemicals and waste products in a sustainable way and so will contribute to future food and environmental security.

ScienceDaily: Agriculture and Food News

Variation in land-use intensity leads to higher biodiversity

Dec. 24, 2013 — If grassland is managed intensively, biodiversity typically declines. A new study led by Bernese plant ecologists shows that it is rare species that suffer the most. These negative effects could be reduced, if farmers varied the intensity of their land use between years.

Globally, the intensification of agricultural land use is considered the leading threat to biodiversity. Previous studies on the impacts of land-use intensity on biodiversity have only looked at single or small groups of organisms. However, individual species can vary greatly in how they respond to different land uses, meaning that the overall impact on biodiversity is often not clear.

A research study, published in the Proceedings of the National Academy of Science (PNAS), led by the Professors Eric Allan and Markus Fischer at the University of Bern, shows that farmers can help protect grassland biodiversity by varying management intensity over time. This reduces some of the negative effects of intensive land use, particularly for rare species.

New index measures ecosystem biodiversity

A team of 58 scientists, from both Switzerland and Germany, assembled a uniquely comprehensive dataset on the biodiversity of up to 49 groups of organisms, including groups of bacteria, fungi, plants and animals. They used data from study sites that they had established in 150 grasslands in three regions of Germany, the Biodiversity Exploratories, which varied from extensively managed and lightly grazed to intensively grazed or mown grasslands with high fertilizer input.

The scientists used these data to compile a novel index of “multidiversity,” which measures total ecosystem biodiversity. “The study showed that overall biodiversity declined very strongly with increasing land-use intensity and that this was particularly true for rarer species,” explains Eric Allan of the Institute of Plant Sciences at the University of Bern. Plants, grasshoppers and butterflies declined most strongly.

According to Eric Allan, the results provide very strong evidence for the importance of extensively managed grasslands for nature conservation: “This new index provides a single measure of biodiversity for an ecosystem and should make it easier to assess the effects of conservation measures or restoration efforts on biodiversity.”

Variation in land-use intensity as new strategy

Interestingly, the scientists also found biodiversity to be much higher in grasslands in which land-use intensity had varied over the last few years. “This suggests that varying management intensity over time could be a novel strategy to maintain biodiversity in grasslands, for instance by altering the number of livestock or the frequency of mowing between years,” explains Markus Fischer

The rare species in the study benefited particularly from changing land use over time: At intermediate land-use intensity, the biodiversity of the rarer species was almost twice as high when land-use intensity varied between years. “This result shows that farmers could do a lot for biodiversity conservation simply by varying the intensity of their land-use between years, as long as the mean intensity of management does not get too high,” says Eric Allan.

ScienceDaily: Agriculture and Food News

Freshwater biodiversity put on the map for planners and policymakers

Oct. 16, 2013 — When it comes to economic growth and environmental impacts, it can seem like Newton’s third law of motion is the rule — for every action, there is an equal and opposite reaction — and that in most cases, the economy prospers and the environment suffers.

A team of UW-Madison researchers is hoping to help change that narrative and add a little ecology to economic decision making by forecasting how future policies regarding urban development and agricultural cultivation may impact aquatic ecosystems, which harbor astounding amounts of biodiversity and provide humans with vital goods and services.

“The idea is to see what future land use changes may look like under different policies, and think about where potential threats to freshwater would be most severe,” says Sebastián Martinuzzi, a post-doctoral researcher at the University of Wisconsin-Madison. “We are not trying to predict the ‘true’ future, but rather to visualize potential economic trends and their environmental consequences.”

Martinuzzi, who works in Professor Volker Radeloff’s lab in the Department of Forest and Wildlife Ecology, is lead author of a report entitled “Land Use Change and Freshwater Conservation,” published Oct. 15 in the journal Global Change Biology. In the study, a team of UW ecologists and collaborating economists mapped out various economic development scenarios and connected them to impacts on freshwater species diversity across the United States.

Every acre of crops put into production and each paved cul-de-sac in a new subdivision can change how water moves across the land, its temperature, and the levels of sediment and pollutants flowing into downstream freshwater ecosystems.

Using computer modeling and GIS mapping, Martinuzzi and the team developed four different scenarios to help illustrate future human endeavors. In their models, the researchers found that the news isn’t all bad. Crop cover is actually projected to go down under certain policy scenarios in the Midwest, which could signal an opportunity to purchase fallow fields for conservation purposes. However, in places like California and the southeastern U.S., urbanization is likely going to be a big stressor that could portend a tough future for fishes and amphibians.

The study was also able to put a number on the give-and-take of economic and ecological considerations. For example, under a “business as usual” scenario where policies remain as they are today, 34 percent of watersheds are expected to be impacted by urban development while, in an “urban containment” scenario, only 13 percent of watersheds would be affected as the spread of urban areas is minimized.

“At a minimum, we hope this can help policy makers or planners think about ways we could minimize the impact from future land development,” says Stephanie Januchowski-Hartley, from UW-Madison’s Center for Limnology and a contributing author of the paper. “If a certain amount [of urban development or crop cover] is going to push 10 or 20 percent of freshwater ecosystems beyond a healthy threshold, then we, as a society, have to start asking ourselves if that is something that we’re all willing to live with.”

ScienceDaily: Agriculture and Food News

Is a constructive conservation the last chance for biodiversity? Pragmatic approach to saving what can be saved

Oct. 10, 2013 — How can biodiversity be preserved in a world in which traditional ecosystems are increasingly being displaced by “human-made nature”? Biologists at the TU Darmstadt and ETH Zurich have developed a new concept for conservation measures that incorporates current landscapes formerly considered ecologically “of little value.” Numerous experiences from islands have shown that this concept has a positive effect on biodiversity. Now the authors are proposing  applying these lessons learned to other landscapes.

In a human-dominated world that contains only little “historical” nature, the term ecosystem can no longer be a synonym for unspoilt nature. The term “novel ecosystems” was coined a few years ago to describe disturbed ecosystems in which biodiversity has been significantly altered as the result of human intervention. “In our new conservation framework we argue that this strict distinction between historic and novel ecosystems should be reconsidered to aid conservation,” pollination biologist Dr. Christopher Kaiser-Bunbury describes the approach, which is not without controversy.

On continents with vast natural parks, such as the USA and Africa, critics fear that the new concept could weaken the protection of historic nature by, for instance, redirecting financial resources towards more active intervention and design of ecosystems. The team of Darmstadt and Zurich biologists, however, propagates a reconciling approach. “Our framework combines strategies that were, until now, considered incompatible. Not only historic wildlands are worth protecting, but also designed cultural landscapes. Given the increased anthropogenic pressure on nature, we propose a multi-facetted approach to preserve biodiversity: to protect historic nature where ecologically viable; to actively create new, intensively managed ecosystems; to accept novel ecosystems as natural, wild landscapes; and to convert agricultural and other cultivated landscapes while generally maintaining land-use priorities.”

Agricultural landscapes “of little value” belong on the agenda

New ecosystems may also include maize fields and banana plantations, as agricultural land can be used to preserve biodiversity. In fact, necessary measures are relatively easy to implement and comparatively inexpensive. Trials in Europe involving hedges and meadow strips along fields, for example, have shown that many animal species use these areas for feeding and nesting. Such modifications also create corridors between habitats that are traditionally worth protecting. “The individual measures proposed here are not novel but what is needed is an overall concept that combines these measures on a landscape level. And this is something that has been tested on many oceanic islands — with considerable success.”

Lessons from islands

The studies by the Darmstadt and Swiss biologists have shown that biodiversity conservation on regionally heterogeneous islands, such as Galapagos, Hawaii, Fiji or Seychelles, illustrates the successful implementation of such an integrated concept. On the Seychelles, for instance, the combined conservation measures include the strict protection of natural cloud forest on a few mountain tops, the management of abandoned cinnamon plantations, and green urban areas such as gardens. The recovery of threatened species and a halt to the decline of native biodiversity are indicators of the success of these conservation strategies. “At the same time, though, we need to know more about how invasive species influence biodiversity,” adds Professor Nico Blüthgen in the light of current investigations by the TU Darmstadt. “For example, native plants on Hawaii have not developed a protective mechanism against immigrant ants and are therefore threatened by their invasion.” His working group addresses the consequences of species extinction on ecosystem functioning.

In another study the ecologists aim to investigate how the concept developed on islands can bet intensively tested in different landscape settings, including on a larger scale on continents.

ScienceDaily: Agriculture and Food News

QUAFETY project shows the prevalence and biodiversity of bacterial pathogens in produce

QUAFETY project shows the prevalence and biodiversity of bacterial pathogens in produce

Scientists of the Department of Food Science and Technology at Agricultural University of Athens (Greece), within the QUAFETY European project (2011-2014), determined the prevalence of Listeria monocytogenes and Escherichia coli O157:H7 in fresh-cut rocket, cucumbers and strawberries.

The detection of both pathogens was based on the respective ISO methods with a parallel study for the comparison of two chromogenic culture media: ALOA and RAPID’L. mono in the former case, CT – SMAC and Fluorocult in the latter.

Confirmation of the suspect colonies was performed by hemolysis, rhamnose and xylose fermentation as well as specific PCR for L. monocytogenes; Latex Test and specific PCR for E. coli O157:H7.

The results of biochemical tests and molecular analyses showed that the prevalence of L. monocytogenes was 7% in rocket, 6% in cucumbers and 3.8% in strawberries, while prevalence of E. coli O157: H7 was 7% in rocket, 3% in cucumbers and 3.8% in strawberries. Furthermore, it was concluded that parallel use of more than one chromogenic media is necessary for accurate estimation of L. monocytogenes and E. coli O157:H7 prevalence.

The same scientists have also assessed the biodiversity of 22 L. monocytogenes and 12 Escherichia coli Ο157:Η7 strains isolated from rocket, cucumber and strawberry samples, as well as the detection of virulence – associated genes.

Genotypic diversity of both pathogens was assessed by RAPD – PCR using M13, UBC155 and HLWL85 as primers and by rep – PCR using (GTG)5 as primer. Results showed that all L. monocytogenes strains belonged to 4b serotype. Many virulence associated genes such as plcB, plcA, actA, hlyA regarding L. monocytogenes and stx2, eae and some of their variants regarding E. coli O157:H7 have been detected. However, none of the isolates contained all necessary genes required for pathogenicity, as detected by published specific – PCR protocols, most probably due to variations in the primer hybridization sequences.

Source: Hadjilouka A., Madjourani K.S., Katsarou A., Koubou V., Paramithiotis S., Mataragas M., Drosinos, E.H., Laboratory of Food Quality Control and Hygiene, Department of Food Science and Technology, Agricultural University of Athens, Greece. www.quafety.eu

Publication date: 9/10/2013
Author: Emanuela Fontana
Copyright: www.freshplaza.com


FreshPlaza.com

QUAFETY project shows the prevalence and biodiversity of bacterial pathogens in produce

QUAFETY project shows the prevalence and biodiversity of bacterial pathogens in produce

Scientists of the Department of Food Science and Technology at Agricultural University of Athens (Greece), within the QUAFETY European project (2011-2014), determined the prevalence of Listeria monocytogenes and Escherichia coli O157:H7 in fresh-cut rocket, cucumbers and strawberries.

The detection of both pathogens was based on the respective ISO methods with a parallel study for the comparison of two chromogenic culture media: ALOA and RAPID’L. mono in the former case, CT – SMAC and Fluorocult in the latter.

Confirmation of the suspect colonies was performed by hemolysis, rhamnose and xylose fermentation as well as specific PCR for L. monocytogenes; Latex Test and specific PCR for E. coli O157:H7.

The results of biochemical tests and molecular analyses showed that the prevalence of L. monocytogenes was 7% in rocket, 6% in cucumbers and 3.8% in strawberries, while prevalence of E. coli O157: H7 was 7% in rocket, 3% in cucumbers and 3.8% in strawberries. Furthermore, it was concluded that parallel use of more than one chromogenic media is necessary for accurate estimation of L. monocytogenes and E. coli O157:H7 prevalence.

The same scientists have also assessed the biodiversity of 22 L. monocytogenes and 12 Escherichia coli Ο157:Η7 strains isolated from rocket, cucumber and strawberry samples, as well as the detection of virulence – associated genes.

Genotypic diversity of both pathogens was assessed by RAPD – PCR using M13, UBC155 and HLWL85 as primers and by rep – PCR using (GTG)5 as primer. Results showed that all L. monocytogenes strains belonged to 4b serotype. Many virulence associated genes such as plcB, plcA, actA, hlyA regarding L. monocytogenes and stx2, eae and some of their variants regarding E. coli O157:H7 have been detected. However, none of the isolates contained all necessary genes required for pathogenicity, as detected by published specific – PCR protocols, most probably due to variations in the primer hybridization sequences.

Source: Hadjilouka A., Madjourani K.S., Katsarou A., Koubou V., Paramithiotis S., Mataragas M., Drosinos, E.H., Laboratory of Food Quality Control and Hygiene, Department of Food Science and Technology, Agricultural University of Athens, Greece. www.quafety.eu

Publication date: 9/10/2013
Author: Emanuela Fontana
Copyright: www.freshplaza.com


FreshPlaza.com

Soil biodiversity will be crucial to future land management and response to climate change

Aug. 12, 2013 — Research by scientists at The University of Manchester and Lancaster shows maintaining healthy soil biodiversity can play an important role in optimising land management programmes to reap benefits from the living soil. The findings, published in the latest edition of the journal PNAS, extend the understanding about the factors that regulate soil biodiversity.

The team says more research on soil food webs — the community of organisms living all or part of their lives in the soil — and their response to land use and climate change could also improve predictions of climate change impacts on ecosystems.

In one of the largest studies of its kind, a team of researchers from across Europe looked at soil life in 60 sites across four countries, the UK, Sweden, Greece and the Czech Republic, to assess the role of soil food webs in nutrient cycles in agricultural soils. Soil food webs describe the community of organisms living all or part of their lives in the soil and their complex living system interacting with other substances such as carbon and nitrogen. The study shows for the first time that there is a strong link between soil organisms and the overall functioning of ecosystems.

Until now most studies which have investigated the reduction of soil biodiversity and how this affects carbon and nitrogen cycling have been laboratory-based or focused on one group of organisms in the soil rather than the wider picture. This is the first time researchers have looked at the entire community of organisms. The team explored soil found under land used in various ways including intensive wheat rotation farming and permanent grassland. It found there were consistent links between soil organisms and soil food web properties and ecosystem functioning on a large scale, across European countries.

Dr Franciska De vries, from The University of Manchester’s Faculty of Life Sciences who was lead author of the research, said: “We found that the condition of the soil was less tied to how the land was used and more influenced by the soil food web properties.

“Soils contain a vast diversity of organisms which are crucially important for humans. These organisms help capture carbon dioxide (CO2) which is crucial for helping to reduce global warming and climate change.

“This research highlights the importance of soil organisms and demonstrates that there is a whole world beneath our feet, inhabited by small creatures that we can’t even see most of the time. By liberating nitrogen for plant growth and locking up carbon in the soil they play an important role in supporting life on Earth.”

The researchers hope the findings will help in predicting how land use and climate change will impact on ecosystems and looking at ways to minimise negative changes.

Dr De vries, from The University of Manchester who carried out the research while at Lancaster University, said: “Soil biodiversity is under threat by a range of pressures such as urbanisation, climate change, pollution and expanding production of food, fibre and biofuel but the topic remains severely understudied.

“We hope that this research will in the longer term will help us to devise ways for farmers, landowners and conservation agencies to optimise the way they manage land to reap benefits from the living soil and reduce carbon emissions.”

ScienceDaily: Agriculture and Food News