Community dynamics of soil-borne fungal communities along elevation gradients in neotropical and palaeotropical forests.

Because of their steep gradients in abiotic and biotic factors, mountains offer an ideal setting to illuminate the mechanisms that underlie patterns of species distributions and community assembly. We compared the composition of taxonomically and functionally diverse fungal communities in soils along five elevational gradients in mountains of the Neo- and Palaeotropics (northern Argentina, southern Brazil, Panama, Malaysian Borneo and Papua New Guinea). Both the richness and composition of soil fungal communities reflect environmental factors, particularly temperature and soil pH, with some shared patterns among neotropical and palaeotropical regions. Community dynamics are characterized by replacement of species along elevation gradients, implying a relatively narrow elevation range for most fungi, which appears to be driven by contrasting environmental preferences among both functional and taxonomic groups. For functional groups dependent on symbioses with plants (especially ectomycorrhizal fungi), the distribution of host plants drives richness and community composition, resulting in important differences in elevational patterns between neotropical and palaeotropical montane communities. The pronounced compositional and functional turnover along elevation gradients implies that tropical montane forest fungi will be sensitive to climate change, resulting in shifts in composition and functionality over time.

Methodological Approaches Frame Insights into Endophyte Richness and Community Composition.

Isolating microbes is vital to study microbiomes, but insights into microbial diversity and ecology can be constrained by recalcitrant or unculturable strains. Culture-free methods (e.g., next-generation sequencing, NGS) have become popular in part because they detect greater richness than culturing alone. Both approaches are used widely to characterize microfungi within healthy leaves (foliar endophytes), but methodological differences among studies can constrain large-scale insights into endophyte ecology. We examined endophytes in a temperate plant community to quantify how certain methodological factors, such as the choice of cultivation media for culturing and storage period after leaf collection, affect inferences regarding endophyte communities; how such effects vary among plant taxa; and how complementary culturing and NGS can be when subsets of the same plant tissue are used for each. We found that endophyte richness and composition from culturing were consistent across five media types. Insights from culturing and NGS were largely robust to differences in storage period (1, 5, and 10 days). Although endophyte richness, composition, and taxonomic diversity identified via culturing vs. NGS differed markedly, both methods revealed host-structured communities. Studies differing only in cultivation media or storage period thus can be compared to estimate endophyte richness, composition, and turnover at scales larger than those of individual studies alone. Our data show that it is likely more important to sample more host species, rather than sampling fewer species more intensively, to quantify endophyte diversity in given locations, with the richest insights into endophyte ecology emerging when culturing and NGS are paired.

Time to -30°C as a predictor of acute success during cryoablation in patients with atrial fibrillation.

BACKGROUND: Freezing rate of second-generation cryoballoon (CB) is a biophysical parameter that could assist pulmonary vein isolation. The aim of this study is to assess freezing rate (time to reach -30°C ([TT-30C]) as an early predictor of acute pulmonary vein isolation using the CB. METHODS: Biophysical data from CB freeze applications within a multicenter, nation-wide CB ablation registry were gathered. Successful application (SA), was defined as achieving durable intraprocedural vein isolation. And SA with time to isolation under 60 s (SA-TTI<60) as achieving durable vein isolation in under 60 s. Logistic regressions were performed and predictive models were built for the data set. RESULTS: 12,488 CB applications from 1,733 atrial fibrillation (AF) ablation procedures were included within 27 centers from a Spanish CB AF ablation registry. SA was achieved in 6,349 of 9,178 (69.2%) total freeze applications, and SA-TTI<60 was obtained in 2,673 of 4,784 (55.9%) freezes where electrogram monitoring was present. TT-30C was shorter in the SA group (33.4 ± 9.2 vs 39.3 ± 12.1 s; p < 0.001) and SA-TTI<60 group (31.8 ± 7.6 vs. 38.5 ± 11.5 s; p < 0.001). Also, a 10 s increase in TT-30C was associated with a 41% reduction in the odds for an SA (odds ratio [OR] 0.59; 95% confidence interval [CI] 0.56-0.63) and a 57% reduction in the odds for achieving SA-TTI<60 (OR 0.43; 95% CI 0.39-0.49), when corrected for electrogram visualization, vein position, and application order. CONCLUSIONS: Time to reach -30°C is an early predictor of the quality of a CB application and can be used to guide the ablation procedure even in the absence of electrogram monitoring.

Screening and evaluation of antiparasitic and in vitro anticancer activities of Panamanian endophytic fungi.

Many compounds produced by fungi have relevant pharmaceutical applications. The purpose of this study was to collect and isolate endophytic fungi from different regions of Panama and then to test their potential therapeutic activities against Leishmania donovani, Plasmodium falciparum, and Trypanosoma cruzi as well as their anticancer activities in MCF-7 cells. Of the 25 fungal isolates obtained, ten of them had good anti-parasitic potential, showing selective activity against L. donovani; four had significant anti-malarial activity; and three inhibited the growth of T. cruzi. Anticancer activity was demonstrated in four isolates. Of the active isolates, Edenia sp. strain F0755, Xylaria sp. strain F1220, Aspergillus sp. strain F1544, Mycoleptodiscus sp. strain F0194, Phomopsis sp. strain F1566, Pycnoporus sp. strain F0305, and Diaporthe sp. strain F1647 showed the most promise based on their selective bioactivity and lack of toxicity in the assays.

Climate and seasonality drive the richness and composition of tropical fungal endophytes at a landscape scale.

Understanding how species-rich communities persist is a foundational question in ecology. In tropical forests, tree diversity is structured by edaphic factors, climate, and biotic interactions, with seasonality playing an essential role at landscape scales: wetter and less seasonal forests typically harbor higher tree diversity than more seasonal forests. We posited that the abiotic factors shaping tree diversity extend to hyperdiverse symbionts in leaves-fungal endophytes-that influence plant health, function, and resilience to stress. Through surveys in forests across Panama that considered climate, seasonality, and covarying biotic factors, we demonstrate that endophyte richness varies negatively with temperature seasonality. Endophyte community structure and taxonomic composition reflect both temperature seasonality and climate (mean annual temperature and precipitation). Overall our findings highlight the vital role of climate-related factors in shaping the hyperdiversity of these important and little-known symbionts of the trees that, in turn, form the foundations of tropical forest biodiversity.

Lessons learned in attempting catheter-based interatrial electrical disconnection for nonpharmacologic rate control of atrial fibrillation or flutter.

PURPOSE: Ablation of atrioventricular (AV) conduction and pacemaker implantation is the therapy of last resort for symptomatic atrial tachyarrythmias when rhythm and rate control fail, but is far from ideal. To evaluate whether interatrial electrical disconnection as a result of catheter ablation is feasible and of potential clinical utility as a means of non-pharmacological heart rate control. METHODS: Eleven patients with medically refractory atrial fibrillation or left atrial flutter and symptomatic rapid ventricular response were included. The ablation strategy consisted primarily of right atrial ablation of the interatrial electrical connections, which were located by electroanatomical activation maps performed during coronary sinus stimulation. Successive activation maps were performed as each connection was blocked. If the procedure was considered unsuccessful AV nodal ablation was performed. RESULTS: The coronary sinus ostium was earliest in 10/11 and could be ablated in 5/10 patients. Interatrial conduction block was only achieved in one patient (9.1%). An unexpected AV nodal modulation with an increase in the Wenckebach cycle length (> 50 ms) occurred in 8/11 patients. These patients remained without pacemaker implantation and only 1/8 required AV nodal ablation during the 1-year follow-up. Quality of life questionnaires indicated significant improvement in patients with AV nodal modulation. CONCLUSION: Interatrial electrical disconnection by right atrial catheter ablation is a not feasible with present day technology. The extensive right atrial septal ablation performed resulted in significant AV nodal modulation in most patients, which persisted and resulted in improvement in quality of life.

Richness and composition of gall-inducing arthropods at Coiba National Park, Panama.

Interest in studying galls and their arthropods inducers has been growing rapidly in the last two decades. However, the Neotropical region is probably the least studied region for gall-inducing arthropods. A study of the richness and composition of gall-inducing arthropods was carried out at Coiba National Park in the Republic of Panama. Field data come from samples obtained between August 1997 and September 1999, with three (two-week long) more intensive samplings. Seventeen sites, representing the main land habitats of Coiba National Park were surveyed. 4942 galls of 50 insect and 9 mite species inducing galls on 50 vascular plants from 30 botanical families were colleted. 62.7% of the galls were induced by gall midges (Diptera, Cecidomyiidae), 15.3% by mites, Eriophyidae, 8.5% by Homoptera, Psyllidae, 6.8% by Coccidae and 5.1% by Phlaeothripidae (Tysanoptera). The host plant families with the most galls were Myrtaceae with seven, Bignoniaceae with five and Euphorbiaceae, Fabaceae and Melastomataceae with four. Leaf galls accounted for about 93% of collected galls. Most leaf galls were pit/blister galls followed by covering and pouch galls. Gall richness per collecting site was between 1 and 19 species. Coiba's gall diversity is discussed in relation to data available from other tropical sites from continental Panama and the Neotropical region. Our results support the idea that it may be premature to conclude that species richness of gall inducers declines near the equator.

Habitual stone-tool-aided extractive foraging in white-faced capuchins, Cebus capucinus.

Habitual reliance on tool use is a marked behavioural difference between wild robust (genus Sapajus) and gracile (genus Cebus) capuchin monkeys. Despite being well studied and having a rich repertoire of social and extractive foraging traditions, Cebus sp. rarely use tools and have never been observed using stone tools. By contrast, habitual tool use by Sapajus is widespread. We review theory and discuss factors which might explain these differences in patterns of tool use between Cebus and Sapajus. We then report the first case of habitual stone tool use in a gracile capuchin: a population of white-faced capuchins (Cebus capucinus imitator) in Coiba National Park, Panama who habitually rely on hammerstone and anvil tool use to access structurally protected food items in coastal areas including Terminalia catappa seeds, hermit crabs, marine snails, terrestrial crabs and other items. This behaviour has persisted on one island in Coiba National Park since at least 2004. From 1 year of camera trapping, we found that stone tool use is strongly male-biased. Of the 205 camera trap days where tool use was recorded, adult females were never observed to use stone tools, although they were frequently recorded at the sites and engaged in scrounging behaviour. Stone tool use occurs year-round in this population; over half of all identifiable individuals were observed participating. At the most active tool use site, 83.2% of days where capuchins were sighted corresponded with tool use. Capuchins inhabiting the Coiba archipelago are highly terrestrial, under decreased predation pressure and potentially experience resource limitation compared to mainland populations-three conditions considered important for the evolution of stone tool use. White-faced capuchin tool use in Coiba National Park thus offers unique opportunities to explore the ecological drivers and evolutionary underpinnings of stone tool use in a comparative within- and between-species context.

A new species of Heliconia (Heliconiaceae) with pendent inflorescence, from Chucantí Private Nature Reserve, eastern Panama.

Heliconia berguidoi (Heliconiaceae), a new species from premontane forest of eastern Panama, is described, illustrated and its conservation status evaluated. Heliconia berguidoi bears pink flowers, an uncommon color in this group. It differs from the Colombian species Heliconia rhodantha and Heliconia sanctae-theresae, the most similar taxa, by the combination of a petiole glabrous except for the woolly base, a very long peduncle, the perianth pubescent at the apex and staminode with cuspidate apex. Heliconia berguidoi is also similar to Heliconia pogonantha in all four of its varieties and to Heliconia ramonensis in two of its four varieties, but differs by a combination of the long peduncle, pink flowers and staminode with cuspidate apex. Fifty-six Heliconia species have been found in Panama, eighteen of them endemic.

ResumenHeliconia berguidoi (Heliconiaceae), una nueva especie de bosque premontano del este de Panamá, es descrita, ilustrada y su estado de conservación evaluado. Heliconia berguidoi tiene flores rosadas, color poco común en este grupo. Difiere de las especies de Colombia Heliconia rhodantha y Heliconia sanctae-theresae, taxones más similares, por la combinación de un pecíolo glabro aunque lanudo en la base, pedúnculo muy largo, ápice del perianto pubescente y estaminoide con el ápice cuspidado. Heliconia berguidoi es también similar a Heliconia pogonantha en sus cuatro variedades y a Heliconia ramonensis en dos de sus cuatro variedades, pero difiere por la combinación de su largo pedúnculo, el color rosado de las flores y el estaminoide con ápice cuspidado. En Panamá se han encontrado cincuenta y seis especies de Heliconia, dieciocho de ellas endémicas.

[A comparative study of the follow-up and hemodynamics in vivo of 21 mm Carpentier-Edwards supra-annular and perimount bioprostheses]. / Estudio comparativo del comportamiento clínico y hemodinámico de las bioprótesis aórticas de Carpentier-Edwards Supra-Annular y Perimount de 21 mm.

INTRODUCTION AND OBJECTIVES: Analysis and comparison of the clinical performance and hemodynamics in vivo of 21 mm Carpentier-Edwards supra-annular (CESA) and Perimount (CEPM) aortic bioprostheses. METHODS: A follow-up study was made of 40 patients implanted a 21 mm CESA (n = 21) or CEPM (n = 19) prosthesis between October 1992 and September 1997. All eligible survivors (14 CESA, 12 CEPM) were assessed echocardiographically. RESULTS: There were no significant differences between models in the effective orifice area (1.6 cm2 for CESA, 1.44 cm2 for CEPM), peak flow rate (rest: 2.5 m/s for CESA, 2.3 m/s for CEPM; post-dobutamine: 3.4 m/s for CESA, 3.3 m/s for CEPM), mean flow rate (rest: 1.7 m/s for CESA, 1.6 m/s for CEPM; post-dobutamine: 2.5 m/s for CESA, 2.2 m/s for CEPM), peak gradient (rest: 28.3 mmHg for CESA, 21.6 mmHg for CEPM; post-dobutamine: 48.4 mmHg for CESA, 41.6 mmHg for CEPM), and mean gradient (rest: 15.8 mmHg for CESA, 12.0 mmHg for CEPM; post-dobutamine: 28.5 mmHg for CESA, 22.5 mmHg for CEPM). CONCLUSION: In our experience, these two prosthetic models have similar hemodynamic characteristics in small aortic annuli.

Bioactivity of fungal endophytes as a function of endophyte taxonomy and the taxonomy and distribution of their host plants.

Fungal endophytes--fungi that grow within plant tissues without causing immediate signs of disease--are abundant and diverse producers of bioactive secondary metabolites. Endophytes associated with leaves of tropical plants are an especially exciting and relatively untapped source of novel compounds. However, one major challenge in drug discovery lies in developing strategies to efficiently recover highly bioactive strains. As part of a 15-year drug discovery project, foliar endophytes were isolated from 3198 plant samples (51 orders, 105 families and at least 232 genera of angiosperms and ferns) collected in nine geographically distinct regions of Panama. Extracts from culture supernatants of >2700 isolates were tested for bioactivity (in vitro percent inhibition of growth, % IG) against a human breast cancer cell line (MCF-7) and the causative agents of malaria, leishmaniasis, and Chagas' disease. Overall, 32.7% of endophyte isolates were highly active in at least one bioassay, including representatives of diverse fungal lineages, host lineages, and collection sites. Up to 17% of isolates tested per assay were highly active. Most bioactive strains were active in only one assay. Fungal lineages differed in the incidence and degree of bioactivity, as did fungi from particular plant taxa, and greater bioactivity was observed in endophytes isolated from plants in cloud forests vs. lowland forests. Our results suggest that using host taxonomy and forest type to tailor plant collections, and selecting endophytes from specific orders or families for cultivation, will markedly increase the efficiency and efficacy of discovering bioactive metabolites for particular pharmaceutical targets.

The importance of beta diversity in local gall-inducing arthropod distribution.

Many studies over the past twenty years have documented the richness of arthropod galling species around the world, and some have proposed hypotheses to explain local and global patterns of galling species richness. However, few studies have been directed toward understanding how the gall-inducing species are locally distributed. The aim of this study was to determine the distribution of gall-inducing arthropods species at Coiba National Park, a tropical habitat on the Pacific coast of Panama. Our results suggest that more gall-inducing species had an aggregated distribution, and gall-inducing arthropod diversity shows a strong beta diversity component. Geographic distance was not correlated with similarity in gall-inducing species composition between the studied sites. This fact has important implications when trying to estimate gall-inducing arthropod richness and general patterns, and could cause contradictory results for hypotheses that attempt to explain the local and global patterns of galling species richness.

The importance of beta diversity in local gall-inducing arthropod distribution

Many studies over the past twenty years have documented the richness of arthropod galling species around the world, and some have proposed hypotheses to explain local and global patterns of galling species richness. However, few studies have been directed toward understanding how the gall-inducing species are locally distributed. The aim of this study was to determine the distribution of gall-inducing arthropods species at Coiba National Park, a tropical habitat on the Pacific coast of Panama. Our results suggest that more gall-inducing species had an aggregated distribution, and gall-inducing arthropod diversity shows a strong beta diversity component. Geographic distance was not correlated with similarity in gall-inducing species composition between the studied sites. This fact has important implications when trying to estimate gall-inducing arthropod richness and general patterns, and could cause contradictory results for hypotheses that attempt to explain the local and global patterns of galling species richness.

Preliminary results with the microwave-modified maze III procedure for the treatment of chronic atrial fibrillation.

Between February 2003 and January 2004 a microwave-modified Maze III procedure was performed as an associated procedure in nine patients in chronic atrial fibrillation undergoing surgery for heart valve disease. Clinical follow-up was carried out in all survivors, and an echocardiographic assessment done in all those in sinus rhythm, during the first week of February 2004. There were six women and three men with a mean age of 60 +/- 9.4 years. Their rhythm at the end of surgery was sinus in 2 patients, nodal in 4, and complete AV block in 3. One patient died in hospital and there patients had no other complications related to the procedure. By the time of hospital discharge, four patients were in sinus rhythm and four were in atrial fibrillation. After a mean follow-up of 5.2 +/- 3.3 months there were no late deaths, 5 patients were in sinus rhythm, 1 required a permanent pacemaker in DDDR mode for persistent sinus bradycardia, and 2 remained in atrial fibrillation. Echocardiographic assessment, performed at a mean of 4.9 +/- 2.5 months after surgery in all patients in sinus rhythm or with a pacemaker, demonstrated biatrial contraction in five patients. The Cox-Maze III procedure can be performed safely and with good results using microwave energy instead of the conventional "cut and sew" technique.