Function of muscle-type lactate dehydrogenase and citrate synthase of the Galápagos marine iguana, Amblyrhynchus cristatus, in relation to temperature

The Galápagos marine iguana, Amblyrhynchus cristatus, is unique among lizards in foraging subtidally, leading to activity across a broad range of ambient temperatures ( approximately 14-40 degrees C). To determine whether the marine iguana shows any biochemical changes consistent with maintaining enzyme function at both warm and cold body temperatures, we examined the function of the aerobic enzyme citrate synthase (CS) and the muscle isoform of the anaerobic enzyme lactate dehydrogenase (A(4)-LDH) in A. cristatus and a confamilial species, Iguana iguana, from 14 to 46 degrees C. We also deduced amino acid sequences from cDNA of each enzyme. In CS, despite two amino acid substitutions, we found no difference in the apparent Michaelis-Menten constant K(m) of oxaloacetate at any temperature, indicating that the substrate affinity of CS in A. cristatus has not adapted to changes in thermal environment. In A(4)-LDH, we used site-directed mutagenesis to show that the substitutions T9A and I283V (A. cristatus --> I. iguana) individually have no effect on kinetics, but together significantly decrease the K(m) of pyruvate and catalytic rate constant (k(cat)) of the A. cristatus ortholog. Thus, our data show that A. cristatus A(4)-LDH has not become cold adapted in response to this species' aquatic foraging behavior, and instead may be consistent with moderate warm adaptation with respect to the I. iguana ortholog.     

Behavioral and physiological adjustments to new predators in an endemic island species, the Galápagos marine iguana

For the past 5 to 15 million years, marine iguanas (Amblyrhynchus cristatus), endemic to the Galápagos archipelago, experienced relaxed predation pressure and consequently show negligible anti-predator behavior. However, over the past few decades introduced feral cats and dogs started to prey on iguanas on some of the islands. We investigated experimentally whether behavioral and endocrine anti-predator responses changed in response to predator introduction. We hypothesized that flight initiation distances (FID) and corticosterone (CORT) concentrations should increase in affected populations to cope with the novel predators. Populations of marine iguanas reacted differentially to simulated predator approach depending on whether or not they were previously naturally exposed to introduced predators. FIDs were larger at sites with predation than at sites without predation. Furthermore, the occurrence of new predators was associated with increased stress-induced CORT levels in marine iguanas. In addition, age was a strong predictor of variation in FID and CORT levels. Juveniles, which are generally more threatened by predators compared to adults, showed larger FIDs and higher CORT baseline levels as well as higher stress-induced levels than adults. The results demonstrate that this naive island species shows behavioral and physiological plasticity associated with actual predation pressure, a trait that is presumably adaptive. However, the adjustments in FID are not sufficient to cope with the novel predators. We suggest that low behavioral plasticity in the face of introduced predators may drive many island species to extinction.     

Characterization of Salmonella occurring at high prevalence in a population of the land iguana Conolophus subcristatus in Galápagos Islands, Ecuador

The aim of the study was to elucidate the association between the zoonotic pathogen Salmonella and a population of land iguana, Colonophus subcristatus, endemic to Galápagos Islands in Ecuador. We assessed the presence of Salmonella subspecies and serovars and estimated the prevalence of the pathogen in that population. Additionally, we investigated the genetic relatedness among isolates and serovars utilising pulsed field gel electrophoresis (PFGE) on XbaI-digested DNA and determined the antimicrobial susceptibility to a panel of antimicrobials. The study was carried out by sampling cloacal swabs from animals (n = 63) in their natural environment on in the island of Santa Cruz. A high prevalence (62/63, 98.4%) was observed with heterogeneity of Salmonella subspecies and serovars, all known to be associated with reptiles and with reptile-associated salomonellosis in humans. Serotyping revealed 14 different serovars among four Salmonella enterica subspecies: S. enterica subsp. enterica (n = 48), S. enterica subsp. salamae (n = 2), S. enterica subsp. diarizonae (n = 1), and S. enterica subsp. houtenae (n = 7). Four serovars were predominant: S. Poona (n = 18), S. Pomona (n = 10), S. Abaetetuba (n = 8), and S.Newport (n = 5). The S. Poona isolates revealed nine unique XbaI PFGE patterns, with 15 isolates showing a similarity of 70%. Nine S. Pomona isolates had a similarity of 84%. One main cluster with seven (88%) indistinguishable isolates of S. Abaetetuba was observed. All the Salmonella isolates were pan-susceptible to antimicrobials representative of the most relevant therapeutic classes. The high prevalence and absence of clinical signs suggest a natural interaction of the different Salmonella serovars with the host species. The interaction may have been established before any possible exposure of the iguanas and the biocenosis to direct or indirect environmental factors influenced by the use of antimicrobials in agriculture, in human medicine or in veterinary medicine.     

Are powerful females powerful enough? Acceleration in gravid green iguanas (Iguana iguana)

One demand placed exclusively on the musculoskeletal systemof females is maintaining locomotor performance with an increasingload over the reproductive cycle. Here, we examine whether gravid(i.e., "pregnant") iguanas can increase their force and powerproduction to support, stabilize, and accelerate the additionalmass of a clutch of eggs. At any acceleration, gravid iguanasproduced very high mechanical power (average total power = 673w/kg; total peak power = 1175 w/kg). While the increase in totalpower was partly a result of greater propulsive power (averagepropulsive power = 25% higher, peak propulsive power = 38% higher),increased vertical power (roughly 200% increase) was the maincontributor. Gravid iguanas were also able to increase peakforces (propulsive = 23%, mediolateral = 44%, vertical = 42%),and step duration (44%) resulting in greater impulses (i.e.,the sum of force produced during a step) to accelerate, balance,and support their increased mass. The increase in step durationand smaller increase in peak propulsive force suggests thatgravid iguanas may be force-limited in the direction of motion.We discuss how biomechanical constraints due to females’reproductive role may influence the evolution of the femalemusculoskeletal systems and contribute to the evolution andmaintenance of ecological dimorphism in lizards.     

Hybridization masks speciation in the evolutionary history of the Galápagos marine iguana

The effects of the direct interaction between hybridization and speciation—two major contrasting evolutionary processes—are poorly understood. We present here the evolutionary history of the Galápagos marine iguana (Amblyrhynchus cristatus) and reveal a case of incipient within-island speciation, which is paralleled by between-island hybridization. In-depth genome-wide analyses suggest that Amblyrhynchus diverged from its sister group, the Galápagos land iguanas, around 4.5 million years ago (Ma), but divergence among extant populations is exceedingly young (less than 50 000 years). Despite Amblyrhynchus appearing as a single long-branch species phylogenetically, we find strong population structure between islands, and one case of incipient speciation of sister lineages within the same island—ostensibly initiated by volcanic events. Hybridization between both lineages is exceedingly rare, yet frequent hybridization with migrants from nearby islands is evident. The contemporary snapshot provided by highly variable markers indicates that speciation events may have occurred throughout the evolutionary history of marine iguanas, though these events are not visible in the deeper phylogenetic trees. We hypothesize that the observed interplay of speciation and hybridization might be a mechanism by which local adaptations, generated by incipient speciation, can be absorbed into a common gene pool, thereby enhancing the evolutionary potential of the species as a whole.     

Remote tracking of Galápagos pink land iguana reveals large elevational shifts in habitat use

Critically endangered Galápagos pink land iguanas, Conolophus marthae, are considered a rare and elusive species. These iguanas are endemic to Wolf Volcano, on Isabela Island (Galápagos), where they persist as a single, very small population on the northwestern slope of the volcano. In an attempt to unveil important information about their ecology and behavior we monitored and analyzed the movement data of a male C. marthae collected over a period of 159 days, from 25 September 2019 until 3 March 2020. We used a custom designed GPS-Wireless Sensor Node (WSN) to remotely track and describe the migration pattern of this individual. Using GPS location data and trajectory reconstruction we documented an altitudinal shift of more than 1000 m. These results not only agree with observations recorded while collecting data in the field but were also used to reconstruct and describe the individual’s migratory behavior, and to document the potential path that this individual, and presumably others of this species, follow while searching for food or mates. The altitudinal shift described whether shared across individuals of the species or part of intraspecific variation, may be related to different factors. Here, we discuss alternative interpretations of this behavior. The urgent need to gather data on the species’ ecology and develop an appropriate conservation strategy underlines the importance of this research. Although it is not possible to draw conclusions for an entire species based on results from one individual, this work represents a significant advancement for the conservation of this species, as it validates the importance of using cutting-edge remote-tracking technology to collect data on a very elusive species, and it reveals ecological traits not previously documented for these critically endangered iguanas.     

Green Iguanas (Iguana iguana) in Puerto Rico: is it time for management?

Iguana iguana is native to Central and South America, and was introduced into Puerto Rico in the 1970s as a result of pet trade. The invasive biology of this reptile has not been studied in Puerto Rico, where its negative effects may threaten local biodiversity. The purposes of this study were to: (1) estimate population densities of I. iguana; (2) describe some aspects of its reproductive biology; and (3) assess its potential impacts. Visual-encounter surveys were performed at Parque Lineal in San Juan and Canal Blasina in Carolina, while nesting activity data were collected at Las Cabezas de San Juan in Fajardo. Densities of I. iguana in Puerto Rico reached a maximum of 223 individuals ha⁻¹, higher than in any known locality in its native range, and showed fluctuations related to seasonality. Our 2008–2009 observations at the nesting sites document that this population of I. iguana is a reproductively successful species, producing more than 100 egg clutches and 2,558 eggs with a 91.4% egg viability. The ability to proliferate in a low predation environment and the absence of good competitors are the major drivers of the population densities observed in Puerto Rico. We found evidence that I. iguana is threatening native biodiversity and impacting infrastructure, agriculture and human safety. Thus, a management program to control the species must soon be developed to prevent this invasive reptile from becoming more widespread and dominant in other localities around the island.     

Gene flow between an endangered endemic iguana, and its wide spread relative, on the island of Utila, Honduras: when is hybridization a threat?

The island endemic Ctenosaura bakeri was listed as critically endangered by the IUCN Redlist Assessment in 2004, 7 years after it was recognized as a distinct species. C. bakeri occupies a portion of Utila, a small continental island located off the northern coast of Honduras. Habitat destruction and over-harvesting are among the top threats facing this species. In addition, morphological evidence of hybridization was recently documented, raising the concern that gene flow from the common and widely distributed C. similis could threaten the genetic distinctiveness of C. bakeri. We show that hybridization occurs only at low levels and is not a current threat to C. bakeri. All ctenosaurs captured for this study were identified to species level without difficulty; none had intermediate or mosaic phenotypes. Sequence analysis of mitochondrial and nuclear markers revealed only two individuals with introgressed genotypes. Molecular analysis of the previously described hybrid showed it to be heterozygous for C. bakeri and C. similis alleles. Hybridization between these two species is possible and occurs occasionally in the wild, and the rate of hybridization could increase if habitat destruction or changes in relative abundance increase the probability of interbreeding. However, the level of gene flow indicated by current data is too low to threaten C. bakeri with genetic swamping or deleterious fitness effects.     

Trends in Cancer Incidence in Maputo,Mozambique, 1991–2008

Background

Very limited information is available regarding the incidence of cancer in sub-Saharan Africa. We analyzed changes in cancer patterns from 1991 to 2008 in Maputo (Mozambique).

Methods

We calculated the rates of incidence of different cancer sites by sex in the 5-year age-group of the population of Maputo city as well as age-standardized rates (ASRs) and average annual percentage changes (AAPC).

Results

Over the 18-year study period a total of 12,674 cases of cancer (56.9% females) were registered with an overall increase in the risk of cancer in both sexes. In males, the most common cancers were those of the prostate, Kaposi sarcoma (KS) and the liver. Prostate cancer showed the most dramatic increase over the whole study period (AAPC +11.3%; 95% CI: 9.7–13.0), with an ASR of 61.7 per 10⁵ in 2003–2008. In females, the most frequent cancers were of the uterine cervix, the breast and KS, with the former increasing along the whole study period (AAPC + 4.7%; 95% CI: 3.4–6) with an ASR of 62.0 per 10⁵ in 2003–2008 as well as breast cancer (AAPC +6.5%; 95%CI: 4.3–8.7).

Conclusions

Overall, the risk of cancer rose in both sexes during the study period, particularly among cancers associated with westernization of lifestyles (prostate, breast), combined with increasingly rising incidences or limited changes in cancers associated with infection and poverty (uterine cervix, liver). Moreover, the burden of AIDS-associated cancers has shown a marked increase.     

Trends in socioeconomic inequalities in cervical,breast, and colorectal cancer screening participation among women in Japan, 2010–2019

BackgroundIt is known that socioeconomic status (SES) influences the outcome of cancer treatment and this could partly be explained by decreased use of cancer screening services by people of lower SES. Many studies have indicated that low SES, including low educational attainment or unstable employment, was related to nonparticipation in cancer screening. However, studies investigating trends in SES inequalities within cancer screening participation are limited. Our objective was to examine trends in SES inequalities in cervical, breast, and colorectal cancer screening participation among women in Japan between 2010 and 2019.MethodsWe analyzed 189,442, 168,571, 163,341, and 150,828 women in 2010, 2013, 2016, and 2019 respectively, using nationally representative cross-sectional surveys. The main outcome variables are participation in each cancer screening. We used educational attainment and employment status as measures for SES. Multivariable logistic regression analysis, adjusted for age, marital status, educational attainment, and employment status was performed to evaluate the associations between SES and nonparticipation in each cancer screening.ResultsOverall participation rates in each cancer screening increased between 2010 and 2019. Low educational attainment and non-permanent employment status were related to nonparticipation in each cancer screening and inequality according to employment status increased within each screening participation during the study period. For example, dispatched workers were more likely to not participate in cervical cancer screening than permanent workers: in 2010, [aOR 1.11 95 %CI: 1.01 –1.21], and in 2019, [aOR 1.46 95 %CI: 1.34–1.60]. The inequality was greatest in colorectal cancer screening nonparticipation, followed by breast and cervical screening.ConclusionsAlthough the participation rates in each cancer screening have increased, inequality in participation in terms of employment status widened among women in Japan between 2010 and 2019. Reducing inequalities in cancer screening participation is essential for cancer screening intervention policies.     

Children's participation in healthcare in the UK--gesture,rhetoric, or real involvement?

In the United Kingdom (England, Wales, Scotland, and Northern Ireland) children and their best interests are protected through a range of best practice initiatives, and legislation and guidance at country, national, European, and global levels. Some of the recent commitment by the government may be the result of enlightened thinking, but some of it has resulted from the aftermath of at least two major healthcare incidents. This article reviews the UK's recent national and international efforts to protect its thirteen million children and ensure that their voices are heard.     

Allometry of aboveground biomasses in mangrove species in Itamaracá, Pernambuco, Brazil

Allometric equations to estimate aboveground biomass (AGB) and plant part biomasses (PPB) of three mangrove species, Rhizophora mangle, Avicennia schaueriana, and Laguncularia racemosa, were determined in Itamaracá, Pernambuco, Brazil (7°48′44″S and 34°49′39″W). Twenty-three to thirty-six trees of each species, ranging in height (H) from 1.6 to 11.8 m and in diameter, at breast height or above prop roots (D), from 2 to 21 cm, were measured, cut, and separated into stems, branches, leaves, and prop roots. Biomass proportions in each tree part were similar among species, excluding prop roots: stems 37–47%, branches 41–46%, and leaves 11–17%. Prop roots represented 37% of AGB in R. mangle. Tree size had a significant but not large influence on biomass distribution among plant parts: as stem diameters increased the proportions allocated to leaves decreased and those to stems and branches increased. AGB and PPB were significantly related to D and D² × H and the best fittings were obtained with power equations. A few equations from literature fitted the data reasonably well for AGB of one or two of the species but resulted in large errors for the others. Applying the equations to previous measurements of tree diameters in a sample area, AGB for the mangrove site was estimated at 105 Mg ha⁻¹, with 78, 19, and 3% corresponding to biomasses of R. mangle, L. racemosa, and A. schaeuriana trees, respectively.     

Tumor necrosis factor-α in macrophages of heart,liver, kidney,and in the pituitary gland

The relationship between myonuclear number, cellular size, succinate dehydrogenase activity, and myosin type was examined in single fiber segments (n=54; 9±3 mm long) mechanically dissected from soleus and plantaris muscles of adult rats. One end of each fiber segment was stained for DNA before quantitative photometric analysis of succinate dehydrogenase activity; the other end was double immunolabelled with fast and slow myosin heavy chain monoclonal antibodies. Mean±S.D. cytoplasmic volume/myonucleus ratio was higher in fast and slow plantaris fibers (112±69 vs. 34±21x10³ m³) than fast and slow soleus fibers (40±20 vs. 30±14x10³ m³), respectively. Slow fibers always had small volumes/myonucleus, regardless of fiber diameter, succinate dehydrogenase activity, or muscle of origin. In contrast, smaller diameter (<70 m) fast soleus and plantaris fibers with high succinate dehydrogenase activity appeared to have low volumes/myonucleus while larger diameter (>70 m) fast fibers with low succinate dehydrogenase activity always had large volume/myonucleus. Slow soleus fibers had significantly greater numbers of myonuclei/mm than did either fast soleus or fast plantaris fibers (116±51 vs. 55±22 and 44±23), respectively. These data suggest that the myonuclear domain is more limited in slow than fast fibers and in the fibers with a high, compared to a low, oxidative metabolic capability.     

Influenza in Outpatient ILI Case-Patients in National Hospital-Based Surveillance,Bangladesh, 2007–2008

Background

Recent population-based estimates in a Dhaka low-income community suggest that influenza was prevalent among children. To explore the epidemiology and seasonality of influenza throughout the country and among all age groups, we established nationally representative hospital-based surveillance necessary to guide influenza prevention and control efforts.

Methodolgy/Principal Findings

We conducted influenza-like illness and severe acute respiratory illness sentinel surveillance in 12 hospitals across Bangladesh during May 2007–December 2008. We collected specimens from 3,699 patients, 385 (10%) which were influenza positive by real time RT-PCR. Among the sample-positive patients, 192 (51%) were type A and 188 (49%) were type B. Hemagglutinin subtyping of type A viruses detected 137 (71%) A/H1 and 55 (29%) A/H3, but no A/H5 or other novel influenza strains. The frequency of influenza cases was highest among children aged under 5 years (44%), while the proportions of laboratory confirmed cases was highest among participants aged 11–15 (18%). We applied kriging, a geo-statistical technique, to explore the spatial and temporal spread of influenza and found that, during 2008, influenza was first identified in large port cities and then gradually spread to other parts of the country. We identified a distinct influenza peak during the rainy season (May–September).

Conclusions/Significance

Our surveillance data confirms that influenza is prevalent throughout Bangladesh, affecting a wide range of ages and causing considerable morbidity and hospital care. A unimodal influenza seasonality may allow Bangladesh to time annual influenza prevention messages and vaccination campaigns to reduce the national influenza burden. To scale-up such national interventions, we need to quantify the national rates of influenza and the economic burden associated with this disease through further studies.     

Isonymous structure in the white population of Córdoba, Argentina, in 1813

Surnames analysis is useful for populations in which only written documents remain, as is the case for historical populations. In Córdoba province, Argentina, census records contain nominal data of inhabitants, including information on sex, age, ethnosocial category, civil status, occupation, place of birth, and residence, that can be analyzed using surnames. Relationship indicators within and among ecclesiastic units in Córdoba were estimated by isonymy for the adult white population registered in the 1813 census. The Rii, Rij, and R(ST) coefficients and the surname abundance indicator (a) were calculated. Lasker's distances among categories of population units were used to cluster the 16 provincial population categories. Gradients for kinship within population and for surname diversity were in agreement with the principal areas and waves of original settlement in the province. The main population clusters reflect those areas, whereas minor clusters coincide with the network of roads existing in the territory by 1813. The structure of the white population in Córdoba province was determined by the geographic location of the original waves of settlement, and it followed a pattern of relationships conditioned by the routes connecting population units in the Colonial period.     

Trends in schistosomiasis-related mortality in Brazil, 2000–2011

Schistosomiasis is an important public health problem, with high morbidity and mortality in endemic countries. We analysed the epidemiological characteristics and time trends of schistosomiasis-related mortality in Brazil. We performed a nationwide study based on official mortality data obtained from the Brazilian Mortality Information System. We included all deaths in Brazil between 2000 and 2011, in which schistosomiasis was mentioned on the death certificate as an underlying or associated cause of death (multiple causes of death). We calculated crude and age-adjusted mortality rates (per 100,000 inhabitants), and proportional mortality rates. Trends over time were assessed using joinpoint regression models. Over the 12-year study period, 12,491,280 deaths were recorded in Brazil. Schistosomiasis was mentioned in 8,756 deaths, including in 6,319 (72.2%) as an underlying cause and in 2,437 (27.8%) as an associated cause. The average annual age-adjusted mortality rate was 0.49 deaths/100,000 inhabitants (95% confidence interval: 0.46–0.52) and proportional mortality rate was 0.070% (95% confidence interval: 0.069–0.072). Males (0.53 deaths/100,000 inhabitants), those aged ⩾70 years (3.41 deaths/100,000 inhabitants), those of brown race/colour (0.44 deaths/100,000 inhabitants), and residents in the Northeast region of Brazil (1.19 deaths/100,000 inhabitants) had the highest schistosomiasis-related death rates. Age-adjusted mortality rates showed a significant decrease at a national level (Annual Percent Change: −2.8%; 95% confidence interval: −4.2 to −2.4) during the studied period. We observed decreasing mortality rates in the Northeast (Annual Percent Change: −2.5%; 95% confidence interval: −4.2 to −0.8), Southeast (Annual Percent Change: −2.2%; 95% confidence interval: −3.6 to −0.9), and Central-West (Annual Percent Change: −7.9%; 95% confidence interval: −11.3 to −4.3) regions, while the rates remained stable in the North and South regions. Despite the reduced mortality, schistosomiasis is still a neglected cause of death in Brazil, with considerable regional differences. Sustainable control measures should focus on increased coverage, and intensified and tailored control measures, to prevent the occurrence of severe forms of schistosomiasis and associated deaths.     

Parental Monitoring,Parent-Adolescent Communication,and Adolescents’ Trust in Their Parents in China

Purpose

Trust is an important aspect of interpersonal relationships, but little is known about adolescents’ interpersonal trust. The aim of the present study was to examine the associations among parental monitoring, parent-adolescent communication, and adolescents’ trust in their parents in China.

Methods

Data in this study were collected as part of the cross-sectional study of children in China. 3349 adolescents (female 48.6%, age range of 12–15 years) were randomly selected from 35 secondary schools in April, 2009 and administered to the Adolescent Interpersonal Trust Scale, the Parental Monitoring Scale, and the Parent-Adolescent Communication Scale.

Results

Adolescents’ trust in their parents was positively related to parental monitoring and parent-adolescent communication. Furthermore, parent-adolescent communication mediated the association between parental monitoring and adolescents’ trust in their parents. The mediation model fit data of both genders and three age groups equally well.

Conclusions

Parental monitoring and parent-adolescent communication play an importance role in fostering adolescents’ trust in their parents.