773 research outputs found
Joint effects of population size and isolation on genetic erosion in fragmented populations: finding fragmentation thresholds for management
Size and isolation of local populations are main parameters of interest when assessing the genetic consequences of habitat fragmentation. However, their relative influence on the genetic erosion of local populations remains unclear. In this study, we first analysed how size and isolation of habitat patches influence the genetic variation of local populations of the Dupont's lark (Chersophilus duponti), an endangered songbird. An information-theoretic approach to model selection allowed us to address the importance of interactions between habitat variables, an aspect seldom considered in fragmentation studies, but which explained up to 65% of the variance in genetic parameters. Genetic diversity and inbreeding were influenced by the size of local populations depending on their degree of isolation, and genetic differentiation was positively related to isolation. We then identified a minimum local population of 19 male territories and a maximum distance of 30km to the nearest population as thresholds from which genetic erosion becomes apparent. Our results alert on possibly misleading conclusions and suboptimal management recommendations when only additive effects are taken into account and encourage the use of most explanatory but easy-to-measure variables for the evaluation of genetic risks in conservation programmes.Peer Reviewe
Restricted gene flow and genetic drift in recently fragmented populations of an endangered steppe bird
Identifying the genetic processes derived from habitat fragmentation is critical for the conservation of endangered species. We conducted an integrated analysis of genetic patterns in the endangered Dupont’s lark (Chersophilus duponti), a circum-Mediterranean songbird threatened by the loss and fragmentation of natural steppes in recent decades. After sampling all the remaining Spanish populations and the two clos¬est North African ones, we found that the Mediterranean Sea acts as a major barrier against gene flow and that recent habitat fragmentation is isolating Spanish populations at different spatial scales. While we found a historical signal of gene flow among Spanish regions, a coalescent model supported that the ancestral panmictic population is evolving into several different units in the absence of current gene flow, genetic drift being more intense in the smaller and more isolated populations. Moreover, small-scale spa¬tial autocorrelation analyses showed that genetic differentiation is also acting within populations. The spatial genetic structure, significant levels of inbreeding and high relatedness within patches raise con¬cerns on the viability of most of the extant populations. We highlight the urgency for steppe patches to be protected, expanded and reconnected, considering the genetic clusters identified here rather than the previously considered eco-geographic regions occupied by the species. Meanwhile, translocations could be considered as a complementary, faster management action to attenuate the crowding and genetic effects of population fragmentation and the extinction risk of small populations without compromising the current local adaptations, culture diversity and genetic clusters already known for the species.Peer Reviewe
Isolation and characterization of microsatellite loci for the endangered Midwife Betic toad Alytes dickhilleni (Discoglossidae)
We have developed eleven polymorphic micro- satellite loci for the amphibian Alytes dickhilleni using an enriched-library approach. We detected 98 alleles in 50 individuals genotyped (mean number of alleles per locus was 8.91) in two different populations in South East Spain. Expected heterozygosities ranged from 0.324 to 0.891 in one population (Arroyo Guadahornillos) and 0.424–0.909 in the other population (Cueva Paria). The levels of poly- morphism of the developed markers render them readily applicable for population genetic studies of diversity, structure, and migration.Peer Reviewe
Hospitalization and mortality rates for heart failure in public hospitals in São Paulo
BACKGROUND: Advances in the treatment of heart failure (HF) have resulted in reduced mortality and hospitalization rates. On the other hand, when hospitalized, patients are at high risk of death. OBJECTIVE: As there are few studies in this group of patients in Brazil, we analyzed the numbers of hospitalization and deaths due to HF in the Brazilian Public Health System (SUS) in the city of São Paulo. METHODS: Historical prospective study carried out between 1992 and 2010. The data were obtained from DATASUS. We used Chi-square and t tests for comparison between the periods 1992-1993 and 2008-2009 and logistic regression models when appropriate. The level of significance was set at 5%. RESULTS: There was a 32% decrease in the number of hospitalizations for HF between 1992-1993 and 2008-2009 (p = 0.002). The in-hospital mortality rate for HF was 15%, with a 15% increase in the period (p = 0.004). Between 1992 and 1993, the mean time of hospitalization for HF was 8.8 days. Between 2008 and 2009, it was 11.3 days (p = 0.001). August was the month with the highest incidence of hospitalizations for HF, 20% higher than in February, the month with the lowest incidence (p = 0.041). CONCLUSION: This study showed changes in trends of hospitalization for HF and mortality over the last two decades. We emphasize important implications: 1: 32% decrease in the number of hospitalizations for HF in SUS hospitals in São Paulo; 2: 25% increase in hospitalization time, and 3: seasonal pattern of hospitalization for HF, with a peak in the third quarter.FUNDAMENTO: Os avanços no tratamento da insuficiência cardíaca (IC) resultaram em redução da taxa de mortalidade e de hospitalização. Por outro lado, quando hospitalizados, os pacientes apresentam alto risco de óbito. OBJETIVO: Como são poucos os estudos com esse grupo de pacientes no Brasil, analisamos os números de internação e óbito por IC no SUS do município de São Paulo. MÉTODOS: Estudo prospectivo histórico realizado entre 1992 e 2010. Os dados foram obtidos no DATASUS. Utilizamos os testes qui-quadrado e T para a comparação entre os períodos 1992-1993 e 2008-2009 e modelos de regressão logística quando apropriado. O nível de significância considerado foi de 5%. RESULTADOS: Houve redução de 32% no número de internações por IC entre 1992-1993 e 2008-2009 (p = 0,002). A taxa de mortalidade hospitalar por IC foi de 15%, com aumento de 15% no período (p = 0,004). Entre 1992-1993, o tempo médio de hospitalização por IC foi de 8,8 dias. Entre 2008-2009, 11,3 dias (p = 0,001). Agosto foi o mês com maior incidência de internações por IC, 20% maior do que fevereiro, mês de menor incidência (p = 0,041). CONCLUSÃO: Este estudo apresentou as modificações nas tendências de hospitalização e mortalidade hospitalar por IC ao longo das duas últimas décadas. Ressaltamos importantes implicações: 1º: redução em 32% no número de internações por IC em hospitais do SUS no município de São Paulo; 2º: aumento de 25% no tempo de hospitalização; e 3º: padrão sazonal de internação por IC, com pico no terceiro trimestre.Universidade Federal de São Paulo (UNIFESP)UNIFESPSciEL
Religious habits of patients submitted to amputation
Background. Religious habits constitute an important component in many people's lives, and this importance
seems to increase with the onset of middle age. The aim of this study was to identify the existence of religious
habits, before and after surgery, of patients who underwent amputation of lower limbs.
Material and methods. Twelve patients, eleven men and one woman, were included in the study, with ages
ranging from 24 to 73 years (mean age 61.5 years). The method of evaluation was by means of an individual
questionnaire, especially elaborated for this research, regarding some religious customs classified as either institutional
or non-institutional. The patients were requested to complete the questionnaire before the surgery, immediately
after the surgery before being released from hospital, and when they returned for a check-up. Normal
ethical considerations were complied with including approval of the local Ethics Research Committee. For statistical
analysis, percentages were utilized.
Results. A total of 83.33% said they were Catholics, 8.33% said they were spiritualists, and 8.33% reported to
be protestants. The majority (91.66%) reported that religion was an important factor in the process of accepting
the illness. Before the amputation, their religious habits included praying (91.66%), frequenting church (83.33%),
watching or listening to religious services (25%), contact with friends from the church (83.33%), and participating
in religious events (41.66%).
Conclusions. Religious habits help patients deal with the stress caused by amputation. Even if some of the habits
are reduced due to with the purpose of providing some acceptance of the act of surgery and to reduce the
symptoms of stress caused
Shaking earth: Non-linear seismic processes and the second law of thermodynamics: A case study from Canterbury (New Zealand) earthquakes
We would like to express our gratitude to GeoNet for making available the data used in this work. This work was partially sup-ported by the RNM104 and RNM194 (Research Groups belonging to Junta de Andalucia, Spain) , the Spanish National Projects [grant project PID2019-109608GB-I00] , and the Junta de Andalucia Project [grant project A-RNM-421-UGR18] . English language editing was performed by Tornillo Scientific.Earthquakes are non-linear phenomena that are often treated as a chaotic natural processes. We propose the use of the Second Law of Thermodynamics and entropy, H, as an indicator of the equilibrium state of a seismically active region (a seismic system). In this sense, in this paper we demonstrate the exportability of first principles (e.g., thermodynamics laws) to others scientific fields (e.g., seismology). We suggest that the relationship between increasing H and the occurrence of large earthquakes reflects the irreversible transition of a system. From this point of view, a seismic system evolves from an unstable initial state (due to external stresses) to a state of reduced stress after an earthquake. This is an irreversible transition that entails an increase in entropy. In other words, a seismic system is in a metastable situation that can be characterised by the Second Law of Thermodynamics. We investigated two seismic episodes in the Canterbury area of New Zealand: the 2010 Christchurch earthquake (M = 7.2) and the 2016 Kaikoura earthquake (M = 7.8). The results are remarkably in line with our theoretical forecasts. In other words, an earthquake, understood as an irreversible transition, must results in an increase in entropy.Research Groups belonging to Junta de Andalucia, Spain RNM104- RNM194Spanish National Projects PID2019-109608GB-I00Junta de Andalucia A-RNM-421-UGR1
Analysis of relatedness and determination of the source of founders in the captive bearded vulture, Gypaetus barbatus, population
Genetic relatedness among founders is a vital parameter in the management of captive populations as kin structure
can have a significant effect on subsequent population structure. Methods for inferring relatedness from
microsatellite markers have all been developed for natural populations; their applicability to captive populations
with unknown founder origins needs therefore testing. We used information derived from 14 microsatellites in
177 individuals and Queller and Goodnight’s approach, to estimate relatedness in the captive bearded vulture
population and to test the assumption of unrelated founders. Mean relatedness of known parent–offspring, fullsib
and half-sib pairs within the captive population were in agreement with theoretical distributions. Pairwise
relatedness values among the founders had a mean of −0.051 (SE ± 0.007) and their distribution did only differ
marginally from the one found in the natural Pyrenean population. A maximum likelihood approach was used to
determine the likelihood of founder pairs to be as closely related as full-sibs or parent–offspring. These results were
combinedwith data from 268 bp mitochondrialDNA control region sequences and studbook information.We could
exclude a close relationship among the majority of the 36 successfully reproducing founders. Our study therefore
removes management concerns about hidden problems of inbreeding and inbreeding depression. It demonstrates
the applicability of relatedness estimates based on microsatellite allele frequency data even in captive populations.
Furthermore, we verified studbook information on the origin of two founders from the Pyrenees, and show the
value of assignment tests based on microsatellites for deducing founder origins and their important role in future
monitoring projects.Peer reviewe
Heterozygosity-fitness correlations and inbreeding depression in two critically endangered mammals
The relation among inbreeding, heterozygosity, and fitness has been studied primarily among outbred populations, and little is known about these phenomena in endangered populations. Most researchers conclude that the relation between coefficient of inbreeding estimated from pedigrees and fitness traits (inbreeding-fitness correlations) better reflects inbreeding depression than the relation between marker heterozygosity and fitness traits (heterozygosity-fitness correlations). However, it has been suggested recently that heterozygosity-fitness correlations should only be expected when inbreeding generates extensive identity disequilibrium (correlations in heterozygosity and homozygosity across loci throughout the genome). We tested this hypothesis in Mohor gazelle (Gazella dama mhorr) and Iberian lynx (Lynx pardinus). For Mohor gazelle, we calculated the inbreeding coefficient and measured heterozygosity at 17 microsatellite loci. For Iberian lynx, we measured heterozygosity at 36 microsatellite loci. In both species we estimated semen quality, a phenotypic trait directly related to fitness that is controlled by many loci and is affected by inbreeding depression. Both species showed evidence of extensive identity disequilibrium, and in both species heterozygosity was associated with semen quality. In the Iberian lynx the low proportion of normal sperm associated with low levels of heterozygosity was so extreme that it is likely to limit the fertility of males. In Mohor gazelle, although heterozygosity was associated with semen quality, inbreeding coefficient was not. This result suggests that when coefficient of inbreeding is calculated on the basis of a genealogy that begins after a long history of inbreeding, the coefficient of inbreeding fails to capture previous demographic information because it is a poor estimator of accumulated individual inbreeding. We conclude that among highly endangered species with extensive identity disequilibrium, examination of heterozygosity-fitness correlations may be an effective way to detect inbreeding depression, whereas inbreeding-fitness correlations may be poor indicators of inbreeding depression if the pedigree does not accurately reflect the history of inbreeding.Peer Reviewe
Disulfide Engineered Lipase to Enhance the Catalytic Activity: A Structure-Based Approach on BTL2
Enhancement, control, and tuning of hydrolytic activity and specificity of lipases are major goals for the industry. Thermoalkaliphilic lipases from the I.5 family, with their native advantages such as high thermostability and tolerance to alkaline pHs, are a target for biotechnological applications. Although several strategies have been applied to increase lipases activity, the enhancement through protein engineering without compromising other capabilities is still elusive. Lipases from the I.5 family suffer a unique and delicate double lid restructuration to transition from a closed and inactive state to their open and enzymatically active conformation. In order to increase the activity of the wild type Geobacillus thermocatenulatus lipase 2 (BTL2) we rationally designed, based on its tridimensional structure, a mutant (ccBTL2) capable of forming a disulfide bond to lock the open state. ccBTL2 was generated replacing A191 and F206 to cysteine residues while both wild type C64 and C295 were mutated to serine. A covalently immobilized ccBTL2 showed a 3.5-fold increment in esterase activity with 0.1% Triton X-100 (2336 IU mg-1) and up to 6.0-fold higher with 0.01% CTAB (778 IU mg-1), both in the presence of oxidizing sulfhydryl agents, when compared to BTL2. The remarkable and industrially desired features of BTL2 such as optimal alkaliphilic pH and high thermal stability were not affected. The designed disulfide bond also conferred reversibility to the enhancement, as the increment on activity observed for ccBTL2 was controlled by redox pretreatments. MD simulations suggested that the most stable conformation for ccBTL2 (with the disulfide bond formed) was, as we predicted, similar to the open and active conformation of this lipase.Financial and logistic support from Colombian Universidad del Valle and COLCIENCIAS (CI 71083-Grant 745-2016-Project 110671250425), Spanish CICYT project BIO-2005-6018576, BFU2017-90030-P, and BFU2011-25326, B. Di G. In addition, thanks to the Spanish MINECO for a FPU fellowship.S
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