... FORTUM, BA, RE CURRIN III, 1993: Crop rotation and nemati-cide effects on the frequency of Me... more ... FORTUM, BA, RE CURRIN III, 1993: Crop rotation and nemati-cide effects on the frequency of Meloidogyne spp. ... TZORTZAKAKIS, EA, MAM ADAM, VC BLOK, C. PARASKEVOPOULOS, K. BOURTZIS, 2005: Occurrence of resistant breaking popula-tions of root-knot nematodes ...
Isolation and expression of effector genes encoding proteins secreted by plant-parasitic nematode... more Isolation and expression of effector genes encoding proteins secreted by plant-parasitic nematodes into a host can be helpful in improving the understanding of parasitic interactions. In this study, calreticulin, a highly conserved Ca2+-binding and multifunctional protein, and beta-1,4-endoglucanase, a cell wall-degrading enzyme, both known to be secreted from oesophageal gland cells and injected through the nematode stylet into host tissue, were analysed. Full-length cDNAs from calreticulin (crt) and beta-1,4-endoglucanase (eng) with an estimated size of 1549 and 1342 bp, respectively, were isolated from the root-lesion nematode Pratylenchus goodeyi (Pg) by RT-PCR and RACE techniques. Pg-crt and Pg-eng cDNAs were characterized in silico, and their expression assessed by semi-quantitative PCR in nematodes exposed to a chemical stress provided by a Solanum nigrum extract showing nematicidal activity. It was demonstrated that the plant extract down-regulated the levels of Pg-crt mRNA,...
The root-lesion nematode, Pratylenchus goodeyi, is a parasite of banana plants, frequently detect... more The root-lesion nematode, Pratylenchus goodeyi, is a parasite of banana plants, frequently detected in Madeira Island (Portugal) affecting culture development and consequently the production, with economical damages. To identify the phytochemicals of Solanum sisymbriifolium and S. nigrum with nematicidal properties and determine the effect of those components on P. goodeyi, an extraction sequence of at least 10 hours each from dried plants was used. The chosen solvent sequence was: dichloromethane, acetone, ethanol and water. According to the results, both plants have in their composition chemical components mainly found in water extracts, which affects the mobility and mortality of the root-lesion nematode. S sisymbriifolium and S. nigrum have potential to be used as a natural and environmentally friendly nematicide to control P. goodeyi.
In this study, a cDNA sequence corresponding to the Bursaphelenchus xylophilus unc-87 homolog gen... more In this study, a cDNA sequence corresponding to the Bursaphelenchus xylophilus unc-87 homolog gene (Bx-unc-87) was identified in B. xylophilus transcriptome and characterized. This cDNA has an 1152-bp-long open-reading frame that is putatively translated into a 383 amino acids peptide. The deduced protein (Bx-UNC-87) contains highly conserved regions of the calponin-like proteins and has high sequence identity to the calponin proteins of other nematodes. In Caenorhabditis elegans, the calponin protein encoded by gene unc-87 is required to maintain the structure of myofilaments in muscle cells of the body wall. The silencing of Bx-unc-87 gene was performed by RNAi, soaking the nematodes in a solution containing dsRNA of this gene. In addition to a no dsRNA control, a non-homologous dsRNA control was also included. The Bx-unc-87 transcription was downregulated in nematodes treated with Bx-unc-87 dsRNA in comparison with the non-dsRNA-treated nematodes. dsRNA-treated nematodes revealed...
Journal of Plant Diseases and Protection -New Series-
In a pot assay, a population of Meloidogyne incognita from Northern Greece, reproduced on the res... more In a pot assay, a population of Meloidogyne incognita from Northern Greece, reproduced on the resistant tomato cv.Silvana carrying the Mi gene and on three susceptible pepper cultivars. Its ability to reproduce on the resistant tomato and on pepper cv. California Wonder was sustainable for several generations. Till now, the only resistant breaking population of M. incognita on resistant tomato found in Greece was a distinct one from Crete which did not reproduce on susceptible pepper cultivars. Thus, the population of M. incognita from Northern Greece represents a new type of a resistant breaking pathotype, reported for the first timein the country, and a potential threat for both resistanttomato crops and susceptible peppers in the field.
ABSTRACT A survey of nematodes associated with branches of cork oak, Quercus suber, a species in ... more ABSTRACT A survey of nematodes associated with branches of cork oak, Quercus suber, a species in decline since the second half of the 20th century, was conducted on two farms located in Alentejo, Portugal. Using specific morphological characters, some nematodes were identified as belonging to the genus Laimaphelenchus and one of the isolates being identified as L. heidelbergi. This research aimed to characterize the Portuguese L. heidelbergi isolate using morphobiometrical and molecular analyses and to analyze its phylogenetic relationship to other Laimaphelenchus spp. Morphometric and morphological characteristics of L. heidelbergi females and males were similar to the original description. For molecular analyses, the mitochondrial DNA region from the cytochrome oxidase subunit I and the D2/D3 expansion segments of the large subunit of rDNA were amplified and sequenced. In phylogenetic analyses, sequences of the Portuguese L. heidelbergi isolate clustered with sequences from the Australian isolate. Laimaphelenchus heidelbergi was originally described from wood of Pinus radiata growing in Australia and is here reported for the first time in Europe and Portugal. Cork oak is a new host record for L. heidelbergi.
Meloidogyne spp., commonly known as rootknot nematodes (RKNs), are economically important plant s... more Meloidogyne spp., commonly known as rootknot nematodes (RKNs), are economically important plant sedentary endoparasites that cause galls on susceptible hosts. The Columbia root-knot nematode (CRKN), M. chitwoodi, is a quarantine A2 type pest by the European and Mediterranean Plant Protection Organization since 1998. This nematode has been found associated with economically important crops such as potato and tomato, causing severe damage and making the agricultural products unacceptable for the fresh market and food processing. In vitro co-culture of host and parasite offers an advantageous experimental system for studying plant-RKN interactions. The structure, growth and production of volatiles of Solanum tuberosum hairy roots (HR) and of S. tuberosum HR/ CRKN co-cultures were compared. HR were induced by inoculation of aseptic potato tuber segments with Rhizobium rhizogenes. Co-cultures were initiated by inoculating HR with sterilized CRKN eggs. Infection with CRKN induced the RKN ...
ABSTRACT The Columbia root-knot nematode (CRKN), Meloidogyne chitwoodi, is an EPPO A2 type quaran... more ABSTRACT The Columbia root-knot nematode (CRKN), Meloidogyne chitwoodi, is an EPPO A2 type quarantine pest since 1998. This nematode causes severe damage in economically important crops such as potato and tomato, making agricultural products unacceptable for the fresh market and food processing. Commonly used nematicidal synthetic chemicals are often environmentally unsafe. Essential oils (EOs) may constitute safer alternatives against RKN. EOs, isolated from 56 plant samples, were tested against CRKN hatching, in direct contact bioassays. Some of the most successful EOs were fractionated and the hydrocarbon molecules (HM) and oxygen-containing molecules (OCM) fractions tested separately. 24 EOs displayed very strong hatching inhibitions (≥90 %) at 2 µL mL−1 and were further tested at lower concentrations. Dysphania ambrosioides, Filipendula ulmaria, Ruta graveolens, Satureja montana and Thymbra capitata EOs revealed the lowest EC50 values (<0.15 µL mL−1). The main compounds of these EOs, namely 2-undecanone, ascaridol, carvacrol, isoascaridol, methyl salicylate, p-cymene and/or γ-terpinene, were putatively considered responsible for CRKN hatching inhibition. S. montana and T. capitata OCM fractions showed hatching inhibitions higher than HM fractions. The comparison of EO and corresponding fractions EC50 values suggests interactions between OCM and HM fractions against CRKN hatching. These species EOs showed to be potential environmentally friendly CRKN hatching inhibitors; nonetheless, bioactivity should be considered globally, since its HM and OCM fractions may contribute, diversely, to the full anti-hatching activity.
Soil is composed of different types of particles which are either natural or of anthropogenic ori... more Soil is composed of different types of particles which are either natural or of anthropogenic origin. Anthropogenic particles are often related to the presence of heavy metals and thus provide information on soil quality. Magnetic parameters can detect the presence of such particles and may be used as a proxy for environmental pollution. This study explores the relationships between magnetic particles and the nematofauna of agricultural soils. Magnetic, pedological, microscopy and nematological analyses were conducted in soils collected from major regions of potato production in Portugal. The magnetic characterisation of soils identified regions with magnetic particles with possible anthropogenic origin. Microscopy analysis revealed the presence of spherical particles dominantly composed of Fe, O and C. A positive and significant relationship was found between saturation isothermal remanent magnetisation (SIRM) and mass-specific susceptibility (χ), confirming the importance the ferrimagnetic fraction to magnetic properties. The nematode communities were composed of nematodes belonging to four trophic groups (bacterial feeding, plant feeders, fungal feeders and omnivores/predators). The relationships between magnetic parameters and the nematodes showed that (1) S−25 has a linear correlation with number of nematodes per kilogram of soil and with plant feeders’ trophic group and (2) SIRM correlates with the bacterial feeders trophic group. This study reveals that magnetic proxies may provide means for detecting regions with higher levels of pollution, possibly related to heavy metals. Due to the large background variability found in magnetic parameters, the sampling spacial mesh should to be further refined and the input of magnetic minerals needs to be locally calibrated.
Nonspecific esterases and malate dehydrogenases of 1-5 females from 40 root-knot nematode populat... more Nonspecific esterases and malate dehydrogenases of 1-5 females from 40 root-knot nematode populations from Portugal were analyzed by electrophoresis in 0.4-mm-thick polyacrylamide gels. Fourteen major bands of esterase activity were detected, corresponding to 10 distinct phenotypes, Meloidogyne javanica and M. hapla had distinct species-specific phenotypes. Two phenotypes occurred in M. arenaria. The most variability was found among M. incognita populations. Of the remaining two phenotypes, one was associated with M. hispanica and the other belonged to a new species. Three malate dehydrogenase phenotypes were discerned on the basis of particular combinations of the eight main bands of activity found. As previously found, esterases were more useful than malate dehydrogenases in identification of the major Meloidogyne species. The host plant had no effect on the nematode esterase or malate dehydrogenase phenotypes.
Three populations of the corn cyst nematode Heterodera zeae, one found in the rhizosphere of a fi... more Three populations of the corn cyst nematode Heterodera zeae, one found in the rhizosphere of a fig tree and two infecting corn, were studied using the morphology and morphometry of cysts and second-stage juveniles, and compared with other populations. The intrapopulation and intraspecific variability are discussed. A simple and improved technique to prepare vulval cones for SEM is described. The non-specific esterase patterns of females, isolated from infected corn, were analyzed by electrophoresis in polyacrylamide gels. Two bands of esterase activity were detected. The occurrence of H. zeae is reported for the first time in Portugal and Europe.
... FORTUM, BA, RE CURRIN III, 1993: Crop rotation and nemati-cide effects on the frequency of Me... more ... FORTUM, BA, RE CURRIN III, 1993: Crop rotation and nemati-cide effects on the frequency of Meloidogyne spp. ... TZORTZAKAKIS, EA, MAM ADAM, VC BLOK, C. PARASKEVOPOULOS, K. BOURTZIS, 2005: Occurrence of resistant breaking popula-tions of root-knot nematodes ...
Isolation and expression of effector genes encoding proteins secreted by plant-parasitic nematode... more Isolation and expression of effector genes encoding proteins secreted by plant-parasitic nematodes into a host can be helpful in improving the understanding of parasitic interactions. In this study, calreticulin, a highly conserved Ca2+-binding and multifunctional protein, and beta-1,4-endoglucanase, a cell wall-degrading enzyme, both known to be secreted from oesophageal gland cells and injected through the nematode stylet into host tissue, were analysed. Full-length cDNAs from calreticulin (crt) and beta-1,4-endoglucanase (eng) with an estimated size of 1549 and 1342 bp, respectively, were isolated from the root-lesion nematode Pratylenchus goodeyi (Pg) by RT-PCR and RACE techniques. Pg-crt and Pg-eng cDNAs were characterized in silico, and their expression assessed by semi-quantitative PCR in nematodes exposed to a chemical stress provided by a Solanum nigrum extract showing nematicidal activity. It was demonstrated that the plant extract down-regulated the levels of Pg-crt mRNA,...
The root-lesion nematode, Pratylenchus goodeyi, is a parasite of banana plants, frequently detect... more The root-lesion nematode, Pratylenchus goodeyi, is a parasite of banana plants, frequently detected in Madeira Island (Portugal) affecting culture development and consequently the production, with economical damages. To identify the phytochemicals of Solanum sisymbriifolium and S. nigrum with nematicidal properties and determine the effect of those components on P. goodeyi, an extraction sequence of at least 10 hours each from dried plants was used. The chosen solvent sequence was: dichloromethane, acetone, ethanol and water. According to the results, both plants have in their composition chemical components mainly found in water extracts, which affects the mobility and mortality of the root-lesion nematode. S sisymbriifolium and S. nigrum have potential to be used as a natural and environmentally friendly nematicide to control P. goodeyi.
In this study, a cDNA sequence corresponding to the Bursaphelenchus xylophilus unc-87 homolog gen... more In this study, a cDNA sequence corresponding to the Bursaphelenchus xylophilus unc-87 homolog gene (Bx-unc-87) was identified in B. xylophilus transcriptome and characterized. This cDNA has an 1152-bp-long open-reading frame that is putatively translated into a 383 amino acids peptide. The deduced protein (Bx-UNC-87) contains highly conserved regions of the calponin-like proteins and has high sequence identity to the calponin proteins of other nematodes. In Caenorhabditis elegans, the calponin protein encoded by gene unc-87 is required to maintain the structure of myofilaments in muscle cells of the body wall. The silencing of Bx-unc-87 gene was performed by RNAi, soaking the nematodes in a solution containing dsRNA of this gene. In addition to a no dsRNA control, a non-homologous dsRNA control was also included. The Bx-unc-87 transcription was downregulated in nematodes treated with Bx-unc-87 dsRNA in comparison with the non-dsRNA-treated nematodes. dsRNA-treated nematodes revealed...
Journal of Plant Diseases and Protection -New Series-
In a pot assay, a population of Meloidogyne incognita from Northern Greece, reproduced on the res... more In a pot assay, a population of Meloidogyne incognita from Northern Greece, reproduced on the resistant tomato cv.Silvana carrying the Mi gene and on three susceptible pepper cultivars. Its ability to reproduce on the resistant tomato and on pepper cv. California Wonder was sustainable for several generations. Till now, the only resistant breaking population of M. incognita on resistant tomato found in Greece was a distinct one from Crete which did not reproduce on susceptible pepper cultivars. Thus, the population of M. incognita from Northern Greece represents a new type of a resistant breaking pathotype, reported for the first timein the country, and a potential threat for both resistanttomato crops and susceptible peppers in the field.
ABSTRACT A survey of nematodes associated with branches of cork oak, Quercus suber, a species in ... more ABSTRACT A survey of nematodes associated with branches of cork oak, Quercus suber, a species in decline since the second half of the 20th century, was conducted on two farms located in Alentejo, Portugal. Using specific morphological characters, some nematodes were identified as belonging to the genus Laimaphelenchus and one of the isolates being identified as L. heidelbergi. This research aimed to characterize the Portuguese L. heidelbergi isolate using morphobiometrical and molecular analyses and to analyze its phylogenetic relationship to other Laimaphelenchus spp. Morphometric and morphological characteristics of L. heidelbergi females and males were similar to the original description. For molecular analyses, the mitochondrial DNA region from the cytochrome oxidase subunit I and the D2/D3 expansion segments of the large subunit of rDNA were amplified and sequenced. In phylogenetic analyses, sequences of the Portuguese L. heidelbergi isolate clustered with sequences from the Australian isolate. Laimaphelenchus heidelbergi was originally described from wood of Pinus radiata growing in Australia and is here reported for the first time in Europe and Portugal. Cork oak is a new host record for L. heidelbergi.
Meloidogyne spp., commonly known as rootknot nematodes (RKNs), are economically important plant s... more Meloidogyne spp., commonly known as rootknot nematodes (RKNs), are economically important plant sedentary endoparasites that cause galls on susceptible hosts. The Columbia root-knot nematode (CRKN), M. chitwoodi, is a quarantine A2 type pest by the European and Mediterranean Plant Protection Organization since 1998. This nematode has been found associated with economically important crops such as potato and tomato, causing severe damage and making the agricultural products unacceptable for the fresh market and food processing. In vitro co-culture of host and parasite offers an advantageous experimental system for studying plant-RKN interactions. The structure, growth and production of volatiles of Solanum tuberosum hairy roots (HR) and of S. tuberosum HR/ CRKN co-cultures were compared. HR were induced by inoculation of aseptic potato tuber segments with Rhizobium rhizogenes. Co-cultures were initiated by inoculating HR with sterilized CRKN eggs. Infection with CRKN induced the RKN ...
ABSTRACT The Columbia root-knot nematode (CRKN), Meloidogyne chitwoodi, is an EPPO A2 type quaran... more ABSTRACT The Columbia root-knot nematode (CRKN), Meloidogyne chitwoodi, is an EPPO A2 type quarantine pest since 1998. This nematode causes severe damage in economically important crops such as potato and tomato, making agricultural products unacceptable for the fresh market and food processing. Commonly used nematicidal synthetic chemicals are often environmentally unsafe. Essential oils (EOs) may constitute safer alternatives against RKN. EOs, isolated from 56 plant samples, were tested against CRKN hatching, in direct contact bioassays. Some of the most successful EOs were fractionated and the hydrocarbon molecules (HM) and oxygen-containing molecules (OCM) fractions tested separately. 24 EOs displayed very strong hatching inhibitions (≥90 %) at 2 µL mL−1 and were further tested at lower concentrations. Dysphania ambrosioides, Filipendula ulmaria, Ruta graveolens, Satureja montana and Thymbra capitata EOs revealed the lowest EC50 values (<0.15 µL mL−1). The main compounds of these EOs, namely 2-undecanone, ascaridol, carvacrol, isoascaridol, methyl salicylate, p-cymene and/or γ-terpinene, were putatively considered responsible for CRKN hatching inhibition. S. montana and T. capitata OCM fractions showed hatching inhibitions higher than HM fractions. The comparison of EO and corresponding fractions EC50 values suggests interactions between OCM and HM fractions against CRKN hatching. These species EOs showed to be potential environmentally friendly CRKN hatching inhibitors; nonetheless, bioactivity should be considered globally, since its HM and OCM fractions may contribute, diversely, to the full anti-hatching activity.
Soil is composed of different types of particles which are either natural or of anthropogenic ori... more Soil is composed of different types of particles which are either natural or of anthropogenic origin. Anthropogenic particles are often related to the presence of heavy metals and thus provide information on soil quality. Magnetic parameters can detect the presence of such particles and may be used as a proxy for environmental pollution. This study explores the relationships between magnetic particles and the nematofauna of agricultural soils. Magnetic, pedological, microscopy and nematological analyses were conducted in soils collected from major regions of potato production in Portugal. The magnetic characterisation of soils identified regions with magnetic particles with possible anthropogenic origin. Microscopy analysis revealed the presence of spherical particles dominantly composed of Fe, O and C. A positive and significant relationship was found between saturation isothermal remanent magnetisation (SIRM) and mass-specific susceptibility (χ), confirming the importance the ferrimagnetic fraction to magnetic properties. The nematode communities were composed of nematodes belonging to four trophic groups (bacterial feeding, plant feeders, fungal feeders and omnivores/predators). The relationships between magnetic parameters and the nematodes showed that (1) S−25 has a linear correlation with number of nematodes per kilogram of soil and with plant feeders’ trophic group and (2) SIRM correlates with the bacterial feeders trophic group. This study reveals that magnetic proxies may provide means for detecting regions with higher levels of pollution, possibly related to heavy metals. Due to the large background variability found in magnetic parameters, the sampling spacial mesh should to be further refined and the input of magnetic minerals needs to be locally calibrated.
Nonspecific esterases and malate dehydrogenases of 1-5 females from 40 root-knot nematode populat... more Nonspecific esterases and malate dehydrogenases of 1-5 females from 40 root-knot nematode populations from Portugal were analyzed by electrophoresis in 0.4-mm-thick polyacrylamide gels. Fourteen major bands of esterase activity were detected, corresponding to 10 distinct phenotypes, Meloidogyne javanica and M. hapla had distinct species-specific phenotypes. Two phenotypes occurred in M. arenaria. The most variability was found among M. incognita populations. Of the remaining two phenotypes, one was associated with M. hispanica and the other belonged to a new species. Three malate dehydrogenase phenotypes were discerned on the basis of particular combinations of the eight main bands of activity found. As previously found, esterases were more useful than malate dehydrogenases in identification of the major Meloidogyne species. The host plant had no effect on the nematode esterase or malate dehydrogenase phenotypes.
Three populations of the corn cyst nematode Heterodera zeae, one found in the rhizosphere of a fi... more Three populations of the corn cyst nematode Heterodera zeae, one found in the rhizosphere of a fig tree and two infecting corn, were studied using the morphology and morphometry of cysts and second-stage juveniles, and compared with other populations. The intrapopulation and intraspecific variability are discussed. A simple and improved technique to prepare vulval cones for SEM is described. The non-specific esterase patterns of females, isolated from infected corn, were analyzed by electrophoresis in polyacrylamide gels. Two bands of esterase activity were detected. The occurrence of H. zeae is reported for the first time in Portugal and Europe.
Project Work (PW) requires student-centered learning and involves the planning, implementation an... more Project Work (PW) requires student-centered learning and involves the planning, implementation and evaluation of a project and, then, the presentation of its results. In this study we intend to reflect on the importance, benefits and constraints of PW methodology in the process of teaching and learning Geosciences. Taking into consideration the studies analyzed, we can conclude that PW is a methodological approach in learning in geosciences, and it can be used to promote scientific literacy and develop important competences in the education of young people as citizens and to contribute to the enhancement of scientific contents.
Educational researchers and teachers are well aware that misconceptions—erroneous ideas that diff... more Educational researchers and teachers are well aware that misconceptions—erroneous ideas that differ from the scientifically accepted ones—are very common amongst students. Daily experiences, creative and perceptive thinking and science textbooks give rise to students’ misconceptions which lead them to draw erroneous conclusions that become strongly attached to their views and somehow affect subsequent learning. The main scope of this study was
to understand what students consider a mineral to be and why. Therefore, the goals were (1) to identify eleventh-grade students’ misconceptions about the mineral concept; (2) to understand which variables (gender, parents’ education level and attitude towards science) influenced students’ conceptions; and (3) to create teaching tools for the prevention of misconceptions. In order to achieve these goals, a diagnostic instrument (DI), constituted of a two-tier diagnostic test and a Science Attitude Questionnaire, was developed to be used with a sample of 89 twelfthgrade students from five schools located in central Portugal. As far as we know, this is the first DI
developed for the analysis of misconceptions about the mineral concept. Data analysis allows us to conclude that students had serious difficulties in understanding the mineral concept, having easily formed misconceptions. The variables gender and parents’ education level influence certain students’ conceptions. This study provides a valuable basis for reflection on teaching and learning strategies, especially on this particular theme.
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Papers by Isabel Abrantes
between magnetic particles and the nematofauna of agricultural soils. Magnetic, pedological, microscopy and nematological analyses were conducted in soils collected from major regions of potato production in Portugal. The magnetic characterisation of soils identified regions with magnetic particles with possible anthropogenic origin. Microscopy analysis revealed the presence of spherical particles dominantly composed of Fe, O and C. A positive and significant relationship
was found between saturation isothermal remanent
magnetisation (SIRM) and mass-specific susceptibility (χ), confirming the importance the ferrimagnetic fraction to magnetic properties. The nematode communities were composed of nematodes belonging to four trophic groups (bacterial feeding, plant feeders, fungal feeders and omnivores/predators). The relationships between magnetic parameters and the nematodes showed that (1) S−25 has a linear correlation with number of nematodes per kilogram of soil and with plant feeders’ trophic group and (2) SIRM correlates with the bacterial feeders trophic group. This study reveals that magnetic proxies may provide means for detecting regions with higher levels of pollution, possibly related to heavy
metals. Due to the large background variability found in magnetic parameters, the sampling spacial mesh should to be further refined and the input of magnetic minerals needs to be locally calibrated.
between magnetic particles and the nematofauna of agricultural soils. Magnetic, pedological, microscopy and nematological analyses were conducted in soils collected from major regions of potato production in Portugal. The magnetic characterisation of soils identified regions with magnetic particles with possible anthropogenic origin. Microscopy analysis revealed the presence of spherical particles dominantly composed of Fe, O and C. A positive and significant relationship
was found between saturation isothermal remanent
magnetisation (SIRM) and mass-specific susceptibility (χ), confirming the importance the ferrimagnetic fraction to magnetic properties. The nematode communities were composed of nematodes belonging to four trophic groups (bacterial feeding, plant feeders, fungal feeders and omnivores/predators). The relationships between magnetic parameters and the nematodes showed that (1) S−25 has a linear correlation with number of nematodes per kilogram of soil and with plant feeders’ trophic group and (2) SIRM correlates with the bacterial feeders trophic group. This study reveals that magnetic proxies may provide means for detecting regions with higher levels of pollution, possibly related to heavy
metals. Due to the large background variability found in magnetic parameters, the sampling spacial mesh should to be further refined and the input of magnetic minerals needs to be locally calibrated.
study we intend to reflect on the importance, benefits and constraints of PW methodology in the process of teaching and learning Geosciences. Taking into consideration the studies
analyzed, we can conclude that PW is a methodological approach in learning in geosciences, and it can be used to promote scientific literacy and develop important
competences in the education of young people as citizens and to contribute to the enhancement of scientific contents.
to understand what students consider a mineral to be and why. Therefore, the goals were (1) to identify eleventh-grade students’ misconceptions about the mineral concept; (2) to understand which variables (gender, parents’ education level and attitude towards science) influenced students’ conceptions; and (3) to create teaching tools for the prevention of misconceptions. In order to achieve these goals, a diagnostic instrument (DI), constituted of a two-tier diagnostic test and a Science Attitude Questionnaire, was developed to be used with a sample of 89 twelfthgrade students from five schools located in central Portugal. As far as we know, this is the first DI
developed for the analysis of misconceptions about the mineral concept. Data analysis allows us to conclude that students had serious difficulties in understanding the mineral concept, having easily formed misconceptions. The variables gender and parents’ education level influence certain students’ conceptions. This study provides a valuable basis for reflection on teaching and learning strategies, especially on this particular theme.