Open Access Government
FCUL-eBook
The sustainability of agriculture
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Science Tech Europa
https://www.scitecheuropa.eu/sustainable-intensification-of-agriculture/84459/
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Open Access Government
The sustainable intensification of agriculture
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ScienceTech
Sustainable intensification of agriculture in Europe
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Europe Dissemination of the project. Science Impact publication
A groundbreaking biofertiliser
Achieving sustainable agriculture
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The fourth Newsletter has been launched
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MICROBIOTEC 17
Microbiology and Biotechnology Congress, 7 - 9th December, was hold by Universidade Católica of Porto.
BioClub has been present with 4 different works:
“Hunting for soil nitrifying prokaryotes: from the nightmare of isolation to the dream of physiological and molecular characterisation" - Inês Santos; Ana Tenreiro; Catarina Gouveia; Manuela Carolino; Juliana Melo; Rogério Tenreiro; Cristina Cruz
"Conventional farming disrupts cooperation among phosphate solubilising bacteria isolated from Carica papa's rhizosphere". J.Melo; L.Carvalho; P.Correia; S. Souza; T.Dias; M. Santana; M. Carolino; N. Aguiar; L.Canellas; C. Cruz; A. Ramos
"Arbuscular mycorrhizal fungi species differ in their capacity to overrule the soil legacy of maize mono cropping". T.Dias; P. Correia; L. Carvalho; J.Melo; A. De Varennes; C. Cruz
"Insights on diazotrophic bacteria and wheat symbiotic interactions by FTICR-MS profiling". A.C.Rocha; J. Melo; T. Dias; M. Carolino; M. Ramos; M. Sousa Silva; C. Cordeiro; R. Tenreiro; C. Cruz.
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Master thesis of Inês Santos
Nitrification: Hunting for soil prokaryotes Abstract
Nitrification: Hunting for soil prokaryotes
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SciTech disseminating BioClub project
Sustainable intensification of agriculture in Europe
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Digital distribution and article impact
Achieving sustainable agriculture
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International Project Dissemination is now available
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A new Newsletter is now available.
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In January the second Newsletter has been launched
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Is mutualism between these living beings a result of war against the rest of the world?
by Francisco Dionísio
Dobzhansky, a prominent 20th century geneticist, wrote a very inspiring (and funny I must say) paper arguing that “Nothing in Biology Makes Sense except in the Light of Evolution” (T. Dobzhansky; The American Biology Teacher, Vol. 35, No. 3 (Mar., 1973), pp. 125-129).
The argument is that, under the light of Evolution, Biology is no more a mass of facts. With Natural Selection, one can have some hope to understand the present, and hopefully make reasonable qualitative predictions of the future. For example, Natural Selection have taught us that bacterial cells gradually became resistant to antibiotics because, by using these drugs, one is selecting for bacterial cells that harbor resistant genes. This fit our intuition, but how can we be sure that bacterial cells are not becoming resistant to antibiotics just because they need to, a kind of Lamarckian process? In a process like this, the expected probability of a cell to become resistant to a certain drug would have an associated low variance, equal to the expected probability to be sure – hence following a Poisson distribution.
According to Natural Selection, however, one is simply selecting for the lucky ones, and they may arise in any moment during bacterial growth – as such, the variance of the probability that mutants arise in a given population is much higher than in the Lamarckian process. These measurement were done long time ago by Delbrück and Luria in 1943 and they concluded that bacteria behave according to Natural Selection (Luria, S. E. and Delbrück, M. (1943). "Mutations of Bacteria from Virus Sensitivity to Virus Resistance". Genetics. 28 (6): 491–511).
Dobzhansky could have argued that “Nothing in Biology Makes Sense except in the Light of Ecology”. Such a paper, however, would not be so strong, simply because one still misses a general theory of Ecology, and specifically back in 1973 when Dobzhansky wrote his argument about Evolution. That is why one still has to look hard to experimental data to make sense of something in Ecology.
This was the case of a master thesis by Ana S. Soares developed in Plant-Soil Ecology group of cE3c, under the supervision of Luís M. Carvalho and A. M. Reis.
Bacterial species of the Streptomyces genus often produce metabolites that harm other bacteria around them. Not surprisingly, then, humans look to them hoping to find new drugs against pathogenic bacteria. Until very recently, one would simply put a few of these cells in a Petri dish and look for antagonistic effect against three other bacterial species commonly found in soil. The same way a physicist would study an electron: alone, or interacting with another single particle perhaps in a vacuum chamber! But, we know that almost nothing in Biology makes sense except under the light of Ecology, so one has to complex things.
The principal aim of the study was to understand whether arbuscular mycorrhizal fungi influences Streptomyces antagonistic effects. Given that one should think under the light of Evolution and Ecology, the authors of the study realized that they had to take into account the interactions between two species or two strains of Streptomyces. By sensing metabolites excreted by an additional Streptomyces isolate the first, for certain, will change its behavior.
The results of this study are very rich:
First, almost half of the 50 Streptomyces isolated from each rhizosphere inhibit at least one of the three bacterial species.
Second, among 300 pairwise combinations, 39% changed its inhibitory behavior when compared with the monoculture case – yes, ecological interactions have a role.
Third, changes in the inhibitory behavior where more common when Streptomyces were coming from the same rhizosphere than when coming from different rhizospheres… why is that?
One may guess that Streptomyces strains coming from the same rhizospheres with a specific arbuscular mycorrhizal fungi community are somehow selected in that environment for a specific interaction degree at a particular node of an interaction-network: either increasing antagonistic behavior or decreasing.
The authors realized that there are no significant differences in intensifications, attenuations nor suppressions, between the cases of Streptomyces pairs coming from the same rhizosphere versus coming from different rhizospheres. So, we are left with the cases of new interactions: almost three times more when Streptomyces were isolated from the same rhizosphere than from different rhizospheres. Recall that the only difference between rhizospheres in the beginning of the experiments: initially (two months before isolation of Streptomyces), rhizospheres differed just because plants were colonizing with different arbuscular mycorrhizal fungi. This means that what is in fact influencing the results just described are these fungi or, of course, the fact that they are coming from the same interacting environment. Again, the authors of the study have the data: when there is no addition of an arbuscular mycorrhizal fungi community to the rhizosphere, a second Streptomyces coming from the same environment mostly likely attenuates the inhibitory interaction.
New interactions (not attenuations) are more common if the two Streptomyces come from a rhizosphere colonized by an arbuscular mycorrhizal fungi community. Apparently, these fungi are selecting for pairs of aggressive Streptomyces. Is mutualism between these living beings a result of war against the rest of the world?
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BioClub will launch bimonthly newsletters
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