Rethinking tropical phenology: insights from long‐term monitoring and novel analytical methods

Here, we introduce the Special Section (SS) on long‐term monitoring and new analytical methods in tropical phenology. The SS puts together nine original papers plus a synthesis, bringing significant advances and new insights into our understanding of tropical phenology across Africa and tropical America. The papers address environmental cues, methodological shortcomings, and provide innovative analytical approaches, opening new pathways, perspective and applications of tropical phenology for forest management and environmental monitoring. The SS is a substantial step toward a more comprehensive overview of trends in tropical phenology, as seven of nine studies evaluate >10‐yr data sets applying new methods of analysis such as hierarchical Bayesian models, generalized additive models, and Fourier analysis. We argue that it is essential to maintain ongoing monitoring programs and build a tropical phenology network at least for long‐term (>10 yr) study sites, providing the means for national and international financial support. Cross‐continental comparisons are now a primary goal, as we work toward a global vision of trends and shifts in tropical phenology in the Anthropocene.     

Contribution of Common Genetic Variants to Obesity and Obesity-Related Traits in Mexican Children and Adults

Background

Several studies have identified multiple obesity-associated loci mainly in European populations. However, their contribution to obesity in other ethnicities such as Mexicans is largely unknown. The aim of this study was to examine 26 obesity-associated single-nucleotide polymorphisms (SNP) in a sample of Mexican mestizos.

Methods

9 SNPs in biological candidate genes showing replications (PPARG, ADRB3, ADRB2, LEPR, GNB3, UCP3, ADIPOQ, UCP2, and NR3C1), and 17 SNPs in or near genes associated with obesity in first, second and third wave GWAS (INSIG2, FTO, MC4R, TMEM18, FAIM2/BCDIN3, BDNF, SH2B1, GNPDA2, NEGR1, KCTD15, SEC16B/RASAL2, NPC1, SFRF10/ETV5, MAF, PRL, MTCH2, and PTER) were genotyped in 1,156 unrelated Mexican-Mestizos including 683 cases (441 obese class I/II and 242 obese class III) and 473 normal-weight controls. In a second stage we selected 12 of the SNPs showing nominal associations with obesity, to seek associations with quantitative obesity-related traits in 3 cohorts including 1,218 Mexican Mestizo children, 945 Mexican Mestizo adults, and 543 Indigenous Mexican adults.

Results

After adjusting for age, sex and admixture, significant associations with obesity were found for 6 genes in the case-control study (ADIPOQ, FTO, TMEM18, INSIG2, FAIM2/BCDIN3 and BDNF). In addition, SH2B1 was associated only with class I/II obesity and MC4R only with class III obesity. SNPs located at or near FAIM2/BCDIN3, TMEM18, INSIG2, GNPDA2 and SEC16B/RASAL2 were significantly associated with BMI and/or WC in the combined analysis of Mexican-mestizo children and adults, and FTO locus was significantly associated with increased BMI in Indigenous Mexican populations.

Conclusions

Our findings replicate the association of 8 obesity-related SNPs with obesity risk in Mexican adults, and confirm the role of some of these SNPs in BMI in Mexican adults and children.     

Activity of Brazilian and Bulgarian propolis against different species of Leishmania

Extracts of propolis samples collected in Brazil and Bulgaria were assayed against four Leishmania species--Leishmania amazonensis, L. braziliensis, L. chagasi from the New World, and L. major from the Old World--associated to different clinical forms of leishmaniasis. The composition of the extracts has been previously characterized by high temperature high resolution gas chromatography coupled to mass spectrometry. Considering the chemical differences among the extracts and the behavior of the parasites, it was observed significant differences in the leishmanicidal activities with IC50/1 day values in the range of 2.8 to 229.3 microg/ml . An overall analysis showed that for all the species evaluated, Bulgarian extracts were more active than the ethanol Brazilian extract. As the assayed propolis extracts have their chemical composition determined it merits further investigation the effect of individual components or their combinations on each Leishmania species.     

Decreased β-adrenoceptor chronotropic response in selenium-deficient mice

With the aim to study if selenium (Se) deficiency affects the basal frequency and cardiac response to isoproterenol (ISO), mice were fed a Se-deficient diet (Se-) or the same diet supplemented with 0.2 ppm Se as sodium selenite (Se+) for 4 wk. Atria frequency, cyclic AMP (cAMP) accumulation, nitric oxide synthase (NOS) activity, and β-adrenoceptor-binding assay were then examined. Results showed that Se-mice have both a reduction in atria frequency as well as in cAMP content but higher NOS activity levels either at basal or after ISO stimulation. These differences were suppressed by feeding Se-mice with a Se-supplemented diet for 1 wk or by inhibition of inducible nitric oxide synthase (iNOS). Alterations observed after ISO stimulation in atria of Se-mice were not related to a β-adrenoceptor expression modification because specific radioligand-binding parameters in cardiac membranes from Se-mice and Se+ mice were similar. The reduced response on rate and cAMP in atria from Se-mice to direct adenylate cyclase (AC) stimulation by forskolin and the shifted upward levels present in 2-amino-4-methylpyridine-treated Se-mice is in agreement with a negative crosstalk between iNOS activity and AC activity in Se-mice.     

Endocrine changes in male stumptailed macaques (Macaca arctoides) as a response to odor stimulation with vaginal secretions

In mammalian species, social chemosignals are important in modulating endocrine reproductive functions. In nonhuman primates, previous studies have described a high frequency of mounting behavior by females in the follicular and periovulatory phases of the menstrual cycle. Stumptailed macaque females do not signal receptivity by means of sexual swellings, as do others macaques, therefore providing a good model in which to study chemical signaling of reproductive status. We exposed anesthetized stumptailed males to vaginal secretions of either late follicular or menses phase or to saline solution to determine the endocrine changes promoting male sexual behavior. In males exposed to follicular secretions, plasma testosterone concentrations were sustained up to 120 min after exposure. Such an effect was not observed in animals exposed to menses or saline odor sources. A luteinizing hormone surge, occurring 30 minutes after exposure to late follicular phase secretion swabs, preceded this sustained testosterone effect. The fact that late follicular scents induce sustained testosterone concentrations provides support to the idea that stumptailed males draw information concerning female reproductive status from the female's vaginal odor.     

Partitioning of anesthetics into a lipid bilayer and their interaction with membrane-bound peptide bundles

Molecular dynamics simulations have been performed to investigate the partitioning of the volatile anesthetic halothane from an aqueous phase into a coexisting hydrated bilayer, composed of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) lipids, with embedded alpha-helical peptide bundles based on the membrane-bound portions of the alpha- and delta-subunits, respectively, of nicotinic acetylcholine receptor. In the molecular dynamics simulations halothane molecules spontaneously partitioned into the DOPC bilayer and then preferentially occupied regions close to lipid headgroups. A single halothane molecule was observed to bind to tyrosine (Tyr-277) residue in the alpha-subunit, an experimentally identified specific binding site. The binding of halothane attenuated the local loop dynamics of alpha-subunit and significantly influenced global concerted motions suggesting anesthetic action in modulating protein function. Steered molecular dynamics calculations on a single halothane molecule partitioned into a DOPC lipid bilayer were performed to probe the free energy profile of halothane across the lipid-water interface and rationalize the observed spontaneous partitioning. Partitioned halothane molecules affect the hydrocarbon chains of the DOPC lipid, by lowering of the hydrocarbon tilt angles. The anesthetic molecules also caused a decrease in the number of peptide-lipid contacts. The observed local and global effects of anesthetic binding on protein motions demonstrated in this study may underlie the mechanism of action of anesthetics at a molecular level.     

Bioaerosol emission from wastewater treatment plants

In this report we describe the results of astudy conducted to better estimate airbornemicroorganisms present in wastewater treatmentplants (WWTP) environments. Air samples weretaken with the Air Sampler MAS 100 impactor(Merck) at each stage of an activated-sludgeWWTP (pre-treatment, primary clarifiers,aeration basins and sludge processors), inorder to determine levels of contaminationaccording to work stations. Culture methodswere used to investigate heterotrophic platecount, moulds and yeasts, total and fecalcoliforms, Pseudomonas aeruginosa andspecies belonging to Mycobacteriumtuberculosis complex, whereas these lastmicroorganisms were also analysed by PolymeraseChain Reaction (PCR) methods. Statisticalanalysis showed that pretreatment and primaryclarifiers were the stages with the highestemission of bioaerosols, and that bioaerosolconcentration at each stage depended on windspeed and daily inflow at the WWTP. Lowconcentrations of P. aeruginosa werefound isolated at pretreatment and primaryclarifiers; however, species of M.tuberculosis complex were not detected at anystage of the treatment plant.