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1.
Proteomics ; 24(14): e2300292, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38676470

RESUMEN

The cuticles of arthropods provide an interface between the organism and its environment. Thus, the cuticle's structure influences how the organism responds to and interacts with its surroundings. Here, we used label-free quantification proteomics to provide a proteome of the moulted cuticle of the aquatic crustacean Daphnia magna, which has long been a prominent subject of studies on ecology, evolution, and developmental biology. We detected a total of 278 high-confidence proteins. Using protein sequence domain and functional enrichment analyses, we identified chitin-binding structural proteins and chitin-modifying enzymes as the most abundant protein groups in the cuticle proteome. Structural cuticular protein families showed a similar distribution to those found in other arthropods and indicated proteins responsible for the soft and flexible structure of the Daphnia cuticle. Finally, cuticle protein genes were also clustered as tandem gene arrays in the D. magna genome. The cuticle proteome presented here will be a valuable resource to the Daphnia research community, informing genome annotations and investigations on diverse topics such as the genetic basis of interactions with predators and parasites.


Asunto(s)
Proteínas de Artrópodos , Daphnia , Proteoma , Animales , Proteoma/metabolismo , Proteoma/análisis , Proteoma/genética , Daphnia/metabolismo , Daphnia/genética , Proteínas de Artrópodos/metabolismo , Proteínas de Artrópodos/genética , Proteínas de Artrópodos/análisis , Proteómica/métodos , Quitina/metabolismo , Quitina/análisis
2.
Plant Cell Environ ; 47(7): 2526-2541, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38515431

RESUMEN

A holistic understanding of plant strategies to acquire soil resources is pivotal in achieving sustainable food security. However, we lack knowledge about variety-specific root and rhizosphere traits for resource acquisition, their plasticity and adaptation to drought. We conducted a greenhouse experiment to phenotype root and rhizosphere traits (mean root diameter [Root D], specific root length [SRL], root tissue density, root nitrogen content, specific rhizosheath mass [SRM], arbuscular mycorrhizal fungi [AMF] colonization) of 16 landraces and 22 modern cultivars of temperate maize (Zea mays L.). Our results demonstrate that landraces and modern cultivars diverge in their root and rhizosphere traits. Although landraces follow a 'do-it-yourself' strategy with high SRLs, modern cultivars exhibit an 'outsourcing' strategy with increased mean Root Ds and a tendency towards increased root colonization by AMF. We further identified that SRM indicates an 'outsourcing' strategy. Additionally, landraces were more drought-responsive compared to modern cultivars based on multitrait response indices. We suggest that breeding leads to distinct resource acquisition strategies between temperate maize varieties. Future breeding efforts should increasingly target root and rhizosphere economics, with SRM serving as a valuable proxy for identifying varieties employing an outsourcing resource acquisition strategy.


Asunto(s)
Adaptación Fisiológica , Sequías , Micorrizas , Raíces de Plantas , Rizosfera , Suelo , Zea mays , Zea mays/fisiología , Zea mays/microbiología , Raíces de Plantas/microbiología , Raíces de Plantas/fisiología , Suelo/química , Micorrizas/fisiología , Fenotipo , Nitrógeno/metabolismo
3.
Anal Bioanal Chem ; 416(15): 3543-3554, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38649517

RESUMEN

Environmental pollution by plastics is a global issue of increasing concern. However, microplastic analysis in complex environmental matrices, such as soil samples, remains an analytical challenge. Destructive mass-based methods for microplastic analysis do not determine plastics' shape and size, which are essential parameters for reliable ecological risk assessment. By contrast, nondestructive particle-based methods produce such data but require elaborate, time-consuming sample preparation. Thus, time-efficient and reliable methods for microplastic analysis are needed. The present study explored the potential of frequency-domain fluorescence lifetime imaging microscopy (FD-FLIM) for rapidly and reliably identifying as well as differentiating plastics and natural materials from terrestrial environments. We investigated the fluorescence spectra of ten natural materials from terrestrial environments, tire wear particles, and eleven different transparent plastic granulates <5 mm to determine the optimal excitation wavelength for identification and differentiation via FD-FLIM under laboratory conditions. Our comparison of different excitation wavelengths showed that 445 nm excitation exhibited the highest fluorescence intensities. 445 nm excitation was also superior for identifying plastic types and distinguishing them from natural materials from terrestrial environments with a high probability using FD-FLIM. We could demonstrate that FD-FLIM analysis has the potential to contribute to a streamlined and time-efficient direct analysis of microplastic contamination. However, further investigations on size-, shape-, color-, and material-type detection limitations are necessary to evaluate if the direct identification of terrestrial environmental samples of relatively low complexity, such as a surface inspection soil, is possible.

4.
Environ Sci Technol ; 57(27): 9925-9933, 2023 07 11.
Artículo en Inglés | MEDLINE | ID: mdl-37364870

RESUMEN

Polystyrene (PS) is an important model polymer for the investigation of effects of microplastic (MP) and nanoplastic (NP) particles on living systems. Aqueous dispersions of PS MP or NP contain residual monomers of styrene. In consequence, it is not clear if the effects observed in standard (cyto)toxicity studies are evoked by the polymer (MP/NP) particle or by residual monomers. We addressed that question by comparing standard PS model particle dispersions with in-house synthesized PS particle dispersions. We proposed a rapid purification method of PS particle dispersions by dialysis against mixed solvents and developed a simple method of UV-vis spectrometry to detect residual styrene in the dispersions. We found that standard PS model particle dispersions, which contain residual monomers, exerted a low but significant cytotoxicity on mammalian cells, while the in-house synthesized PS, after rigorous purification to reduce the styrene content, did not. However, the PS particles per se but not the residual styrene in both PS particle dispersions resulted in immobilization of Daphnia. Only by using freshly monomer-depleted particles, will it be possible in the future to assess the (cyto)toxicities of PS particles, avoiding an otherwise not controllable bias effect of the monomer.


Asunto(s)
Microplásticos , Poliestirenos , Animales , Poliestirenos/toxicidad , Microplásticos/toxicidad , Plásticos , Polímeros , Solventes , Mamíferos
5.
Anal Bioanal Chem ; 415(15): 2975-2987, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-36939884

RESUMEN

One of the biggest issues in microplastic (MP, plastic items <5 mm) research is the lack of standardisation and harmonisation in all fields, reaching from sampling methodology to sample purification, analytical methods and data analysis. This hampers comparability as well as reproducibility among studies. Concerning chemical analysis of MPs, Fourier-transform infrared (FTIR) spectroscocopy is one of the most powerful tools. Here, focal plane array (FPA) based micro-FTIR (µFTIR) imaging allows for rapid measurement and identification without manual preselection of putative MP and therefore enables large sample throughputs with high spatial resolution. The resulting huge datasets necessitate automated algorithms for data analysis in a reasonable time frame. Although solutions are available, little is known about the comparability or the level of reliability of their output. For the first time, within our study, we compare two well-established and frequently applied data analysis algorithms in regard to results in abundance, polymer composition and size distributions of MP (11-500 µm) derived from selected environmental water samples: (a) the siMPle analysis tool (systematic identification of MicroPlastics in the environment) in combination with MPAPP (MicroPlastic Automated Particle/fibre analysis Pipeline) and (b) the BPF (Bayreuth Particle Finder). The results of our comparison show an overall good accordance but also indicate discrepancies concerning certain polymer types/clusters as well as the smallest MP size classes. Our study further demonstrates that a detailed comparison of MP algorithms is an essential prerequisite for a better comparability of MP data.

6.
Proteomics ; 22(10): e2100289, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-35143708

RESUMEN

Aquatic pollution is an increasing problem and requires extensive research efforts to understand associated consequences and to find suitable solutions. The crustacean Daphnia is a keystone species in lacustrine ecosystems by connecting primary producers with higher trophic levels. Therefore, Daphnia is perfectly suitable to investigate biological effects of freshwater pollution and is frequently used as an important model organism in ecotoxicology. The field of ecotoxicoproteomics has become increasingly prevalent, as proteins are important for an organism's physiology and respond rapidly to changing environmental conditions. However, one obstacle in proteome analysis of Daphnia is highly abundant proteins like vitellogenin, decreasing the analytical depth of proteome analysis. To improve proteome coverage in Daphnia, we established an easy-to-use procedure based on the LC-MS/MS of whole daphnids and the dissected Daphnia gut, which is the main tissue getting in contact with soluble and particulate pollutants, separately. Using a comprehensive spectral library, generated by gas-phase fractionation and a data-independent acquisition method, we identified 4621 and 5233 protein groups at high confidence (false discovery rate < 0.01) in Daphnia and Daphnia gut samples, respectively. By combining both datasets, a proteome coverage of 6027 proteins was achieved, demonstrating the effectiveness of our approach.


Asunto(s)
Daphnia , Proteoma , Animales , Cromatografía Liquida , Daphnia/metabolismo , Ecosistema , Proteoma/metabolismo , Espectrometría de Masas en Tándem
7.
Histochem Cell Biol ; 157(2): 127-137, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34750664

RESUMEN

Acquiring comprehensive knowledge about the uptake of pollutants, impact on tissue integrity and the effects at the molecular level in organisms is of increasing interest due to the environmental exposure to numerous contaminants. The analysis of tissues can be performed by histological examination, which is still time-consuming and restricted to target-specific staining methods. The histological approaches can be complemented with chemical imaging analysis. Chemical imaging of tissue sections is typically performed using a single imaging approach. However, for toxicological testing of environmental pollutants, a multimodal approach combined with improved data acquisition and evaluation is desirable, since it may allow for more rapid tissue characterization and give further information on ecotoxicological effects at the tissue level. Therefore, using the soil model organism Eisenia fetida as a model, we developed a sequential workflow combining Fourier transform infrared spectroscopy (FTIR) and matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) for chemical analysis of the same tissue sections. Data analysis of the FTIR spectra via random decision forest (RDF) classification enabled the rapid identification of target tissues (e.g., digestive tissue), which are relevant from an ecotoxicological point of view. MALDI imaging analysis provided specific lipid species which are sensitive to metabolic changes and environmental stressors. Taken together, our approach provides a fast and reproducible workflow for label-free histochemical tissue analyses in E. fetida, which can be applied to other model organisms as well.


Asunto(s)
Sistema Digestivo/citología , Procesamiento de Imagen Asistido por Computador , Aprendizaje Automático , Oligoquetos/citología , Animales , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Espectroscopía Infrarroja por Transformada de Fourier
8.
Langmuir ; 38(29): 8748-8756, 2022 07 26.
Artículo en Inglés | MEDLINE | ID: mdl-35736564

RESUMEN

The environmental fate and toxicity of microplastic particles are dominated by their surface properties. In the environment, an adsorbed layer of biomolecules and natural organic matter forms the so-called eco-corona. A quantitative description of how this eco-corona changes the particles' colloidal interactions is still missing. Here, we demonstrate with colloidal probe-atomic force microscopy that eco-corona formation on microplastic particles introduces a compressible film on the surface, which changes the mechanical behavior. We measure single particle-particle interactions and find a pronounced increase of long-range repulsive interactions upon eco-corona formation. These force-separation characteristics follow the Alexander-de Gennes (AdG) polymer brush model under certain conditions. We further compare the obtained fitting parameters to known systems like polyelectrolyte multilayers and propose these as model systems for the eco-corona. Our results show that concepts of fundamental polymer physics, like the AdG model, also help in understanding more complex systems like biomolecules adsorbed to surfaces, i.e., the eco-corona.


Asunto(s)
Microplásticos , Polímeros , Microscopía de Fuerza Atómica , Plásticos , Propiedades de Superficie
9.
Ecotoxicol Environ Saf ; 242: 113877, 2022 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-35849903

RESUMEN

Microplastic particles (MP) and nanoplastic particles (NP) as persistent anthropogenic pollutants may impact environmental and human health. A relevant potential source of primary MP and NP is water-based dispersion paint which are commonly used in any household. Given the worldwide high application volume of dispersion paint and their diverse material composition MP and NP may enter the environment with unforeseeable consequences. In order to understand the relevance of these MP and NP from paint dispersion we investigated the components of two representative wall paints and analyzed their composition in detail. The different paint components were then investigated for their impact on the model organism Daphnia magna and on a murine cell line. Plastic NP, dissolved polymers, titanium dioxide NPs, and calcium carbonate MPs demonstrated adverse effects in both biological test systems, indicating detrimental consequences of several typical components of wall paints upon release into the environment. The outcome of this study may form the basis for the evaluation of impact on other organisms, environmental transport and impact, other related technical materials and for the development of strategies for the prevention of potential detrimental effects on organisms.


Asunto(s)
Microplásticos , Contaminantes Químicos del Agua , Animales , Daphnia , Humanos , Ratones , Pintura/toxicidad , Plásticos/toxicidad , Polímeros , Contaminantes Químicos del Agua/análisis
10.
Environ Sci Technol ; 54(4): 2078-2090, 2020 02 18.
Artículo en Inglés | MEDLINE | ID: mdl-31999440

RESUMEN

Research on microplastics in soils is still uncommon, and the existing publications are often incomparable due to the use of different sampling, processing, and analytical methods. Given the complex nature of soils, a suitable and efficient method for standardized microplastic analysis in the soil matrix has yet to be found. This paper proposes a critical review on the different published methods for sampling, extraction, purification, and identification/quantification of microplastics in complex environmental matrices, with the main focus on their applicability for soil samples. While large microplastic particles can be manually sorted out and verified with chemical analysis, sample preparation for smaller microplastic analysis is usually more difficult. Of the analytical approaches proposed in the literature, some are established, whereas others are a proof of principle and have not yet been applied to environmental samples. For the sake of development, all approaches are discussed and assessed for their potential applicability for soil samples. So far, none of the published methods seems ideally suitable for the analysis of smaller microplastics in soil samples, but slight modifications and combinations of methods may prove promising and need to be explored.


Asunto(s)
Contaminantes del Suelo , Contaminantes Químicos del Agua , Monitoreo del Ambiente , Microplásticos , Plásticos , Suelo
11.
BMC Ecol ; 20(1): 1, 2020 01 16.
Artículo en Inglés | MEDLINE | ID: mdl-31941480

RESUMEN

BACKGROUND: Coexistence is enabled by ecological differentiation of the co-occurring species. One possible mechanism thereby is resource partitioning, where each species utilizes a distinct subset of the most limited resource. This resource partitioning is difficult to investigate using empirical research in nature, as only few species are primarily limited by solely one resource, rather than a combination of multiple factors. One exception are the shell-dwelling hermit crabs, which are known to be limited under natural conditions and in suitable habitats primarily by the availability of gastropod shells. In the present study, we used two co-occurring terrestrial hermit crab species, Coenobita rugosus and C. perlatus, to investigate how resource partitioning is realized in nature and whether it could be a driver of coexistence. RESULTS: Field sampling of eleven separated hermit crab populations showed that the two co-occurring hermit crab species inhabit the same beach habitat but utilize a distinct subset of the shell resource. Preference experiments and principal component analysis of the shell morphometric data thereby revealed that the observed utilization patterns arise out of different intrinsic preferences towards two distinct shell shapes. While C. rugosus displayed a preference towards a short and globose shell morphology, C. perlatus showed preferences towards an elongated shell morphology with narrow aperture. CONCLUSION: The two terrestrial hermit crab species occur in the same habitat but have evolved different preferences towards distinct subsets of the limiting shell resource. Resource partitioning might therefore be the main driver of their ecological differentiation, which ultimately allowed these co-occurring species to coexist in their environment. As the preferred shell morphology of C. rugosus maximizes reproductive output at the expense of protection, while the preferred shell morphology of C. perlatus maximizes protection against predation at the expense of reproductive output, shell resource partitioning might reflect different strategies to respond to the same set of selective pressures occurring in beach habitats. This work offers empirical support for the competitive exclusion principle-hypothesis and demonstrates that hermit crabs are an ideal model organism to investigate resource partitioning in natural populations.


Asunto(s)
Anomuros , Gastrópodos , Animales , Ecosistema
12.
Environ Sci Technol ; 51(24): 14283-14292, 2017 Dec 19.
Artículo en Inglés | MEDLINE | ID: mdl-29110472

RESUMEN

Micro-Fourier transform infrared (micro-FTIR) spectroscopy and Raman spectroscopy enable the reliable identification and quantification of microplastics (MPs) in the lower micron range. Since concentrations of MPs in the environment are usually low, the large sample volumes required for these techniques lead to an excess of coenriched organic or inorganic materials. While inorganic materials can be separated from MPs using density separation, the organic fraction impedes the ability to conduct reliable analyses. Hence, the purification of MPs from organic materials is crucial prior to conducting an identification via spectroscopic techniques. Strong acidic or alkaline treatments bear the danger of degrading sensitive synthetic polymers. We suggest an alternative method, which uses a series of technical grade enzymes for purifying MPs in environmental samples. A basic enzymatic purification protocol (BEPP) proved to be efficient while reducing 98.3 ± 0.1% of the sample matrix in surface water samples. After showing a high recovery rate (84.5 ± 3.3%), the BEPP was successfully applied to environmental samples from the North Sea where numbers of MPs range from 0.05 to 4.42 items m-3. Experiences with different environmental sample matrices were considered in an improved and universally applicable version of the BEPP, which is suitable for focal plane array detector (FPA)-based micro-FTIR analyses of water, wastewater, sediment, biota, and food samples.


Asunto(s)
Plásticos , Aguas Residuales , Contaminantes Químicos del Agua , Mar del Norte , Compuestos Orgánicos , Espectroscopía Infrarroja por Transformada de Fourier
13.
Proc Biol Sci ; 282(1816): 20151440, 2015 Oct 07.
Artículo en Inglés | MEDLINE | ID: mdl-26423840

RESUMEN

The waterflea Daphnia is a model to investigate the genetic basis of phenotypic plasticity resulting from one differentially expressed genome. Daphnia develops adaptive phenotypes (e.g. morphological defences) thwarting predators, based on chemical predator cue perception. To understand the genomic basis of phenotypic plasticity, the description of the precedent cellular and neuronal mechanisms is fundamental. However, key regulators remain unknown. All neuronal and endocrine stimulants were able to modulate but not induce defences, indicating a pathway of interlinked steps. A candidate able to link neuronal with endocrine responses is the multi-functional amine dopamine. We here tested its involvement in trait formation in Daphnia pulex and Daphnia longicephala using an induction assay composed of predator cues combined with dopaminergic and cholinergic stimulants. The mere application of both stimulants was sufficient to induce morphological defences. We determined dopamine localization in cells found in close association with the defensive trait. These cells serve as centres controlling divergent morphologies. As a mitogen and sclerotization agent, we anticipate that dopamine is involved in proliferation and structural formation of morphological defences. Furthermore, dopamine pathways appear to be interconnected with endocrine pathways, and control juvenile hormone and ecdysone levels. In conclusion, dopamine is suggested as a key regulator of phenotypic plasticity.


Asunto(s)
Daphnia/fisiología , Dopamina/metabolismo , Cadena Alimentaria , Conducta Predatoria , Transducción de Señal , Animales , Fenotipo , Especificidad de la Especie
14.
Mol Ecol ; 24(15): 3901-17, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26111196

RESUMEN

Phenotypic plasticity, the ability of one genotype to express different phenotypes in response to changing environmental conditions, is one of the most common phenomena characterizing the living world and is not only relevant for the ecology but also for the evolution of species. Daphnia, the water flea, is a textbook example for predator-induced phenotypic plastic defences; however, the analysis of molecular mechanisms underlying these inducible defences is still in its early stages. We exposed Daphnia magna to chemical cues of the predator Triops cancriformis to identify key processes underlying plastic defensive trait formation. To get a more comprehensive idea of this phenomenon, we studied four genotypes with five biological replicates each, originating from habitats characterized by different predator composition, ranging from predator-free habitats to habitats containing T. cancriformis. We analysed the morphologies as well as proteomes of predator-exposed and control animals. Three genotypes showed morphological changes when the predator was present. Using a high-throughput proteomics approach, we found 294 proteins which were significantly altered in their abundance after predator exposure in a general or genotype-dependent manner. Proteins connected to genotype-dependent responses were related to the cuticle, protein synthesis and calcium binding, whereas the yolk protein vitellogenin increased in abundance in all genotypes, indicating their involvement in a more general response. Furthermore, genotype-dependent responses at the proteome level were most distinct for the only genotype that shares its habitat with Triops. Altogether, our study provides new insights concerning genotype-dependent and general molecular processes involved in predator-induced phenotypic plasticity in D. magna.


Asunto(s)
Daphnia/genética , Ecosistema , Conducta Predatoria , Proteoma/genética , Animales , Daphnia/anatomía & histología , Europa (Continente) , Femenino , Cadena Alimentaria , Genotipo , Fenotipo , Proteómica
15.
Proc Natl Acad Sci U S A ; 109(38): 15377-82, 2012 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-22949653

RESUMEN

The effectiveness of antipredator defenses is greatly influenced by the environment in which an organism lives. In aquatic ecosystems, the chemical composition of the water itself may play an important role in the outcome of predator-prey interactions by altering the ability of prey to detect predators or to implement defensive responses once the predator's presence is perceived. Here, we demonstrate that low calcium concentrations (<1.5 mg/L) that are found in many softwater lakes and ponds disable the ability of the water flea, Daphnia pulex to respond effectively to its predator, larvae of the phantom midge, Chaoborus americanus. This low-calcium environment prevents development of the prey's normal array of induced defenses, which include an increase in body size, formation of neck spines, and strengthening of the carapace. We estimate that this inability to access these otherwise effective defenses results in a 50-186% increase in the vulnerability of the smaller juvenile instars of Daphnia, the stages most susceptible to Chaoborus predation. Such a change likely contributes to the observed lack of success of daphniids in most low-calcium freshwater environments, and will speed the loss of these important zooplankton in lakes where calcium levels are in decline.


Asunto(s)
Daphnia/fisiología , Plancton/fisiología , Conducta Predatoria , Agua/química , Adaptación Fisiológica , Animales , Tamaño Corporal , Calcio/química , Calcio/metabolismo , Relación Dosis-Respuesta a Droga , Ambiente , Cadena Alimentaria , Microscopía de Fuerza Atómica/métodos , Modelos Biológicos , Fenotipo , Factores de Tiempo
16.
BMC Genomics ; 15: 306, 2014 Apr 24.
Artículo en Inglés | MEDLINE | ID: mdl-24762235

RESUMEN

BACKGROUND: Phenotypic plasticity in defensive traits occurs in many species when facing heterogeneous predator regimes. The waterflea Daphnia is well-known for showing a variety of these so called inducible defences. However, molecular mechanisms underlying this plasticity are poorly understood so far. We performed proteomic analysis on Daphnia magna exposed to chemical cues of the predator Triops cancriformis. D. magna develops an array of morphological changes in the presence of Triops including changes of carapace morphology and cuticle hardening. RESULTS: Using the 2D-DIGE technique, 1500 protein spots could be matched and quantified. We discovered 179 protein spots with altered intensity when comparing Triops exposed animals to a control group, and 69 spots were identified using nano-LC MS/MS. Kairomone exposure increased the intensity of spots containing muscle proteins, cuticle proteins and chitin-modifying enzymes as well as enzymes of carbohydrate and energy metabolism. The yolk precursor protein vitellogenin decreased in abundance in 41 of 43 spots. CONCLUSION: Identified proteins may be either directly involved in carapace stability or reflect changes in energy demand and allocation costs in animals exposed to predator kairomones. Our results present promising candidate proteins involved in the expression of inducible defences in Daphnia and enable further in depth analysis of this phenomenon.


Asunto(s)
Daphnia/metabolismo , Proteómica , Animales , Daphnia/fisiología , Conducta Predatoria
17.
BMC Biol ; 11: 113, 2013 Nov 18.
Artículo en Inglés | MEDLINE | ID: mdl-24245584

RESUMEN

BACKGROUND: Inducible defenses are a common and widespread form of phenotypic plasticity. A fundamental factor driving their evolution is an unpredictable and heterogeneous predation pressure. This heterogeneity is often used synonymously to quantitative changes in predation risk, depending on the abundance and impact of predators. However, differences in 'modality', that is, the qualitative aspect of natural selection caused by predators, can also cause heterogeneity. For instance, predators of the small planktonic crustacean Daphnia have been divided into two functional groups of predators: vertebrates and invertebrates. Predators of both groups are known to cause different defenses, yet predators of the same group are considered to cause similar responses. In our study we question that thought and address the issue of how multiple predators affect the expression and evolution of inducible defenses. RESULTS: We exposed D. barbata to chemical cues released by Triops cancriformis and Notonecta glauca, respectively. We found for the first time that two invertebrate predators induce different shapes of the same morphological defensive traits in Daphnia, rather than showing gradual or opposing reaction norms. Additionally, we investigated the adaptive value of those defenses in direct predation trials, pairing each morphotype (non-induced, Triops-induced, Notonecta-induced) against the other two and exposed them to one of the two predators. Interestingly, against Triops, both induced morphotypes offered equal protection. To explain this paradox we introduce a 'concept of modality' in multipredator regimes. Our concept categorizes two-predator-prey systems into three major groups (functionally equivalent, functionally inverse and functionally diverse). Furthermore, the concept includes optimal responses and costs of maladaptions of prey phenotypes in environments where both predators co-occur or where they alternate. CONCLUSION: With D. barbata, we introduce a new multipredator-prey system with a wide array of morphological inducible defenses. Based on a 'concept of modality', we give possible explanations how evolution can favor specialized defenses over a general defense. Additionally, our concept not only helps to classify different multipredator-systems, but also stresses the significance of costs of phenotype-environment mismatching in addition to classic 'costs of plasticity'. With that, we suggest that 'modality' matters as an important factor in understanding and explaining the evolution of inducible defenses.


Asunto(s)
Daphnia/anatomía & histología , Cadena Alimentaria , Conducta Predatoria/fisiología , Adaptación Fisiológica/genética , Animales , Evolución Biológica , Daphnia/genética , Fenotipo
18.
J Morphol ; 285(2): e21668, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38361258

RESUMEN

Research on eusocial bee species like Bombus terrestris is primarily focused on the worker caste, which is why their morphology and anatomy are already well described. This includes the alimentary tract, which is adapted for feeding on nectar and pollen. Located at the transition between crop and ventriculus is a highly specialised compartment, the proventriculus. In female workers of B. terrestris, the proventriculus is surrounded by muscles and consists of four anterior lips. A detailed description, however, is only provided for B. terrestis worker bees while studies on the proventriculus of the male reproductive caste are absent. Here, we provide a detailed analysis of the differences between the proventriculus of the B. terrestris males and females through morphometrics, histology and scanning electron microscopy imaging, and unravel a distinct sexual dimorphism. The male proventriculus is wider resulting in a greater volume than the female proventriculus. Histological analysis revealed 4 distinctive chambers of the male proventriculus, which are completely covered with hairs on the inside. In contrast, those chambers in the proventriculus of female B. terrestris, are only rudimentarily present forming only small pouches with hairs in the junctions between the proventricular folds inside the proventriculus. The morphological differences in the proventriculus may be based on different modi vivendi, as males do not return to the colony and fly longer distances. This and the synthesis of sperm and mating plug might require higher energy reserves, leading to the necessity of higher food storage capacities.


Asunto(s)
Himenópteros , Abejas , Masculino , Femenino , Animales , Proventrículo , Caracteres Sexuales , Semen , Reproducción
19.
Heliyon ; 10(3): e25133, 2024 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-38322960

RESUMEN

Microplastic pollution of the environment has been extensively studied, with recent studies focusing on the prevalence of microplastics in the environment and their effects on various organisms. Identification methods that simplify the extraction and analysis process to the point where the extraction can be omitted are being investigated, thus enabling the direct identification of microplastic particles. Currently, microplastic samples from environmental matrices can only be identified using time-consuming extraction, sample processing, and analytical methods. Various spectroscopic methods are currently employed, such as micro Fourier-transform infrared, attenuated total reflectance, and micro Raman spectroscopy. However, microplastics in environmental matrices cannot be directly identified using these spectroscopic methods. Investigations using frequency-domain fluorescence lifetime imaging microscopy (FD-FLIM) to identify and differentiate plastics from environmental materials have yielded promising results for directly identifying microplastics in an environmental matrix. Herein, two artificially prepared environmental matrices that included natural soil, grass, wood, and high-density polyethylene were investigated using FD-FLIM. Our first results showed that we successfully identified one plastic type in the two artificially prepared matrices using FD-FLIM. However, further research must be conducted to improve the FD-FLIM method and explore its limitations for directly identifying microplastics in environmental samples.

20.
Sci Total Environ ; 950: 174252, 2024 Jun 27.
Artículo en Inglés | MEDLINE | ID: mdl-38942304

RESUMEN

The agricultural sector plays a pivotal role in driving the economy of many developing countries. Any dent in this economical structure may have a severe impact on a country's population. With rising climate change and increasing pollution, the agricultural sector is experiencing significant damage. Over time this cumulative damage will affect the integrity of food crops and create food security issues around the world. Therefore, an early warning system is needed to detect possible stress on food crops. Here we present a review of the recent developments in nanomaterial-based Surface Enhanced Raman Spectroscopy (SERS) substrates which could be utilized to monitor agricultural crop responses to natural and anthropogenic stress. Initially, our review delves into diverse and cost-effective strategies for fabricating SERS substrates, emphasizing their intelligent utilization across various agricultural scenarios. In the second phase of our review, we spotlight the specific application of SERS in addressing critical food security issues. By detecting nutrients, hormones, and effector molecules in plants, SERS provides valuable insights into plant health. Furthermore, our exploration extends to the detection of contaminants, chemicals, and foodborne pathogens within plants, showcasing the versatility of SERS in ensuring food safety. The cumulative knowledge derived from these discussions illustrates the transformative potential of SERS in bolstering the agricultural economy. By enhancing precision in nutrient management, monitoring plant health, and enabling rapid detection of harmful substances, SERS emerges as a pivotal tool in promoting sustainable and secure agricultural practices. Its integration into agricultural processes not only augments productivity but also establishes a robust defence against potential threats to crop yield and food quality. As SERS continues to evolve, its role in shaping the future of agriculture becomes increasingly pronounced, promising a paradigm shift in how we approach and address challenges in food production and safety.

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