Biology subjects

Campos, M.

Publications and source records attributed to Campos, M..

24 records · Page 2Linked to original sources

bioRxiv2021

Ground cover presence in organic olive orchards affects the interaction of natural enemies against Prays oleae, promoting an effective egg predation

The olive moth, Prays oleae, is one of the most common insects that damages olives in the Mediterranean region. The establishment of ground cover within olive orchards has been promoted in this region in recent years to avoid erosion and soil degradation. Nevertheless, its role as a shelter for natural enemies of pests has been controversial. In this study, we have investigated the effectiveness of the biological control of P. oleae in organic olive orchards with ground cover (mowed) and without ground cover (tilled). For this, (1) we assessed the relationship between predated eggs and the abundance of natural enemies in both types of orchards; (2) we compared both the potential damage of the pest and the egg hatching in the two types of orchards; and (3) we examined the interaction amongst families of natural enemies and P. oleae (as adults and as predated eggs). The results showed that there is a high rate of predation in the studied olive orchards, 81% of the eggs were predated, 12.2% hatched, and 6.9% were live eggs. However, mowed orchards were more effective for controlling P. oleae by means of egg predation rather than tilled orchards, i.e., in mowed orchards, whilst the potential damage of the pest was higher, egg hatching was rather low. The structure of the adult arthropod community, i.e., the composition and abundance of families of natural enemies did not differ between the orchards, but the abundance of the families Anthocoridae, Miridae and Scelionidae was significantly higher in the mowed orchards. Finally, the interaction amongst natural enemies and P. oleae showed that the families that better explained the effects on egg predation were Aeolothripidae, Anthocoridae, Miridae, Chrysopidae (predators), and Formicidae (omnivore). We discuss the results in terms of ecological interactions of trophic guilds and we conclude that the establishment and maintenance of ground cover in organic olive orchards, at least in June and July, is of great significance because it positively affects the egg predation of P. oleae. This effect is especially significant when there is a low abundance of natural enemies in the olive orchards.

ecology↗

bioRxiv2020

Simulating the Influence of Conjugative Plasmids Kinetic Values on the Multilevel Dynamics of Antimicrobial Resistance in a Membrane Computing Model

Plasmids harboring antibiotic resistance genes differ in their kinetic values as plasmid conjugation rate, segregation rate by incompatibility with related plasmids, rate of stochastic loss during replication, cost reducing the host-cell fitness, and frequency of compensatory mutations to reduce plasmid cost, depending on the cell mutation frequency. How variation in these values influence the success of a plasmid and their resistance genes in complex ecosystems, as the microbiota? Genes are located in plasmids, plasmids in cells, cells in populations. These populations are embedded in ensembles of species in different human hosts, are able to exchange between them bacterial ensembles during cross-infection and are located in the hospital or the community setting, under various levels of antibiotic exposure. Simulations using new membrane computing methods help predict the influence of plasmid kinetic values on such multilevel complex system. In our simulation, conjugation frequency needed to be at least 10-3 to clearly influence the dominance of a strain with a resistant plasmid. Host strains able to stably maintain two copies of similar plasmids harboring different resistances, coexistence of these resistances can occur in the population. Plasmid loss rates of 10-4 or 10-5 or plasmid fitness costs [≥]0.06 favor the plasmids located in the most abundant species. The beneficial effect of compensatory mutations for plasmid fitness cost is proportional to this cost, only at high mutation frequencies (10-3-10-5). Membrane computing helps set a multilevel landscape to study the effect of changes in plasmid kinetic values on the success of resistant organisms in complex ecosystems.

microbiology↗

bioRxiv2018

Nucleoid size scaling and intracellular organization of translation across bacteria

The scaling of organelles with cell size is thought to be exclusive to eukaryotes. Here, we demonstrate that similar scaling relationships hold for the nucleoid in bacteria. Despite the absence of a nuclear membrane, nucleoid size strongly correlates with cell size, independent of changes in DNA amount and across various nutrient conditions. This correlation is observed in diverse bacteria, revealing a near-constant ratio between nucleoid and cell size for a given species. As in eukaryotes, the nucleocytoplasmic ratio in bacteria varies greatly among species. This spectrum of nucleocytoplasmic ratios is independent of genome size, and instead appears linked to the average cell size of the population. Bacteria with different nucleocytoplasmic ratios have different biophysical properties of the cytoplasm, impacting the mobility and localization of ribosomes. Together, our findings identify new organizational principles and biophysical features of bacterial cells, implicating the nucleocytoplasmic ratio and cell size as determinants of the intracellular organization of translation.

microbiology↗

bioRxiv2018

Genetic heterogeneity in Anopheles darlingi related to biting behavior in western Amazon

In the Amazon Basin, Anopheles (Nyssorhynchus) darlingi is the most aggressive and effective malaria vector. In endemic areas, behavioral aspects of anopheline species such as host preference, biting time and resting location after a blood meal have a key impact on malaria transmission dynamics and transmission control strategies. An. darlingi present a variety in behavior throughout its broad distribution including blood feeding related. To investigate the genetic basis of its biting behaviors, host-seeking An. darlingi were collected in two settlements (Granada and Remansinho) in Acre, Brazil. Mosquitoes were classified by captured location (indoors or outdoors) and time (dusk or dawn). Genome-wide SNPs were used to assess the degree of genetic diversity and structure in these groups. There was evidence of genetic component of biting behavior regarding both location and time in this species. This study supports that An. darlingi blood-feeding behavior has a genetic component. Additional ecological and genomic studies may help to understand the genetic basis of mosquito behavior and address appropriate surveillance and vector control.\n\nAuthor SummaryMalaria is a disease caused by parasite of the genus Plasmodium and is transmitted by mosquitoes of the genus Anopheles. In the Amazon Basin, the main malaria vector is Anopheles darlingi, which is present in high densities in this region. Egg development requires that females of this mosquito seek hosts for blood meals. Anopheles females blood feeding may occur indoor or outdoor the houses and typically from the sunset to dawn. Anopheles darlingi in particular present great variability regarding its behaviour, presenting variety of peak biting times and patterns. This work shows that there is a genetic component that partially explains these two behaviors: location of the blood meal (inside or outside the houses) and time of feeding. Single nucleotide polymorphisms (SNPs) scattered throughout the genome of Anopheles darlingi showed genetic diversity and structure in these groups. A comprehensive understanding of the genetic basis for mosquito behaviour may support innovative vector surveillance and control strategies.

epidemiology↗

bioRxiv2018

Multi-Hierarchical Dynamics of Antimicrobial Resistance Simulated in a Nested Membrane Computing Model

Membrane Computing is a bio-inspired computing paradigm, whose devices are the so-called membrane systems or P systems. The P system designed in this work reproduces complex biological landscapes in the computer world. It uses nested \"membrane-surrounded entities\" able to divide, propagate and die, be transferred into other membranes, exchange informative material according to flexible rules, mutate and being selected by external agents. This allows the exploration of hierarchical interactive dynamics resulting from the probabilistic interaction of genes (phenotypes), clones, species, hosts, environments, and antibiotic challenges. Our model facilitates analysis of several aspects of the rules that govern the multi-level evolutionary biology of antibiotic resistance. We examine a number of selected landscapes where we predict the effects of different rates of patient flow from hospital to the community and viceversa, cross-transmission rates between patients with bacterial propagules of different sizes, the proportion of patients treated with antibiotics, antibiotics and dosing in opening spaces in the microbiota where resistant phenotypes multiply. We can also evaluate the selective strength of some drugs and the influence of the time-0 resistance composition of the species and bacterial clones in the evolution of resistance phenotypes. In summary, we provide case studies analyzing the hierarchical dynamics of antibiotic resistance using a novel computing model with reciprocity within and between levels of biological organization, a type of approach that may be expanded in the multi-level analysis of complex microbial landscapes.

microbiology↗

bioRxiv2017

Genome-wide phenotypic analysis of growth, cell morphogenesis and cellcycle events in Escherichia coli.

Cell size, cell growth and the cell cycle are necessarily intertwined to achieve robust bacterial replication. Yet, a comprehensive and integrated view of these fundamental processes is lacking. Here, we describe an image-based quantitative screen of the single-gene knockout collection of Escherichia coli, and identify many new genes involved in cell morphogenesis, population growth, nucleoid (bulk chromosome) dynamics and cell division. Functional analyses, together with high-dimensional classification, unveil new associations of morphological and cell cycle phenotypes with specific functions and pathways. Additionally, correlation analysis across ~4,000 genetic perturbations shows that growth rate is surprisingly not predictive of cell size. Growth rate was also uncorrelated with the relative timings of nucleoid separation and cell constriction. Rather, our analysis identifies scaling relationships between cell size and nucleoid size and between nucleoid size and the relative timings of nucleoid separation and cell division. These connections suggest that the nucleoid links cell morphogenesis to the cell cycle.\n\n\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=121 SRC=\"FIGDIR/small/101832_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (43K):\norg.highwire.dtl.DTLVardef@63d469org.highwire.dtl.DTLVardef@e7117org.highwire.dtl.DTLVardef@22a436org.highwire.dtl.DTLVardef@4b0167_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗