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Concept: Alexander von Humboldt


In March 1800, Alexander von Humboldt observed the extraordinary spectacle of native fisherman collecting electric eels (Electrophorus electricus) by “fishing with horses” [von Humboldt A (1807) Ann Phys 25:34-43]. The strategy was to herd horses into a pool containing electric eels, provoking the eels to attack by pressing themselves against the horses while discharging. Once the eels were exhausted, they could be safely collected. This legendary tale of South American adventures helped propel Humboldt to fame and has been recounted and illustrated in many publications, but subsequent investigators have been skeptical, and no similar eel behavior has been reported in more than 200 years. Here I report a defensive eel behavior that supports Humboldt’s account. The behavior consists of an approach and leap out of the water during which the eel presses its chin against a threatening conductor while discharging high-voltage volleys. The effect is to short-circuit the electric organ through the threat, with increasing power diverted to the threat as the eel attains greater height during the leap. Measurement of voltages and current during the behavior, and assessment of the equivalent circuit, reveal the effectiveness of the behavior and the basis for its natural selection.

Concepts: Electricity, Fish, Eel, Electric eel, Electric fish, Alexander von Humboldt, Lisa Germano, Mark Oliver Everett


Global climate change is driving species poleward and upward in high-latitude regions, but the extent to which the biodiverse tropics are similarly affected is poorly known due to a scarcity of historical records. In 1802, Alexander von Humboldt ascended the Chimborazo volcano in Ecuador. He recorded the distribution of plant species and vegetation zones along its slopes and in surrounding parts of the Andes. We revisited Chimborazo in 2012, precisely 210 y after Humboldt’s expedition. We documented upward shifts in the distribution of vegetation zones as well as increases in maximum elevation limits of individual plant taxa of >500 m on average. These range shifts are consistent with increased temperatures and glacier retreat on Chimborazo since Humboldt’s study. Our findings provide evidence that global warming is strongly reshaping tropical plant distributions, consistent with Humboldt’s proposal that climate is the primary control on the altitudinal distribution of vegetation.

Concepts: Earth, Climate change, Solar variation, Andes, Global warming, Glacier mass balance, Alexander von Humboldt, Chimborazo


During the 1790s, Alexander von Humboldt (1769-1859), who showed an early interest in many facets of natural philosophy and natural history, delved into the controversial subject of galvanism and animal electricity, hoping to shed light on the basic nature of the nerve force. He was motivated by his broad worldview, the experiments of Luigi Galvani, who favored animal electricity in more than a few specialized fishes, and the thinking of Alessandro Volta, who accepted specialized fish electricity but was not willing to generalize to other animals, thinking Galvani’s frog experiments flawed by his use of metals. Differing from many German Naturphilosophen, who shunned “violent” experiments, the newest instruments, and detailed measurement, Humboldt conducted thousands of galvanic experiments on animals and animal parts, as well as many on his own body, some of which caused him great pain. He interpreted his results as supporting some but not all of the claims made by both Galvani and Volta. Notably, because of certain negative findings and phenomenological differences, he remained skeptical about the intrinsic animal force being qualitatively identical to true electricity. Hence, he referred to a “galvanic force,” not animal electricity, in his letters and publications, a theoretical position he would abandon with Volta’s help early in the new century.

Concepts: Fish, Battery, Galvanic cell, Alexander von Humboldt, Luigi Galvani, Alessandro Volta, Galvanism, Voltaic pile


Ishwar Singh speaks to Benjamin Walden, Commissioning Editor. Ishwar Singh is a Senior Lecturer in biological chemistry at the School of Pharmacy, University of Lincoln. Prior to Lincoln, he had held many prestigious fellowships such as the Alexander von Humboldt fellowship, Germany; and Senior Research Fellowship, DANIDA, Denmark and CSIR, India. He is an organic chemist. He has developed bioconjugations for DNA, RNA and polymer modifications. He is currently leading research in novel antimicrobials based on rational design against clinically important resistant bacteria (such as methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, mycobacteria, Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa), biologics delivery, peptides, sequence-selective DNA cross linking, nanoparticles modifications for drug delivery and diagnostic applications.

Concepts: DNA, Protein, Amino acid, Molecular biology, Antibiotic resistance, Chemistry, Biochemistry, Alexander von Humboldt


Colombia is the country with the highest bird diversity in the world. Despite active research in ornithology, compelling morphological information of most bird species is still sparse. However, morphological information is the baseline to understand how species respond to environmental variation and how ecosystems respond to species loss. As part of a national initiative, the Instituto Alexander von Humboldt in collaboration with twelve Colombian institutions and seven biological collections, measured up to 15 morphological traits of 9892 individuals corresponding to 606 species: 3492 from individuals captured in field and 6400 from museum specimens. Species measured are mainly distributed in high Andean forest, páramo, and wetland ecosystems. Overall, seven ornithological collections in Colombia and 18 páramo complexes throughout Colombia were visited from 2013 to 2015. The morphological traits involved measurements from bill (total and exposed culmen, bill width and depth), wing (length, area, wingspan and the distance between longest primary and longest secondary), tail (length and shape), tarsus (length), hallux (length and claw hallux) and weight. The number of measured specimens per species was variable, ranging from 1 to 321 individuals with a median of 4 individuals per species. Overall, this database gathered morphological information for more than 30% of Colombian bird diversity. No copyright, proprietary, or cost restrictions apply; the data should be cited appropriately when used. This article is protected by copyright. All rights reserved.

Concepts: Conservation biology, Evolution, Biology, Bird, Units of measurement, Colombia, Copyright, Alexander von Humboldt


Carrion’s disease is a major re-emerging and occupational health disease. This bibliometric study aimed to evaluate scientific production on this disease both globally and in Latin America. SCI-E, MEDLINE/GoPubMed, SCOPUS, ScIELO, and LILACS databases were searched for Carrion’s disease-related articles. They were classified according to publication year, type, city and institution of origin, international cooperation, scientific journal, impact factor, publication language, author(s), and H-index. There were 170 articles in SCI-E. The USA was the largest contributor (42.9%), followed by Peru (24.1%) and Spain (12.4%). Latin American publications were cited 811 times (regional H-index=18). There were 335 articles in SCOPUS: 25.9%, 11.6%, and 8.3% were published by the USA, Peru, and Spain, respectively. Latin American publications were cited 613 times (H-index=12): Peru, Colombia, and Brazil received the most citations (n=395, H-index=10; n=61, H-index=1; and n=54, H-index=4, respectively). The most scientifically productive American institution was the University of Montana (2.9% of American production). In Peru, it was the Institute of Tropical Medicine Alexander von Humboldt of Peruvian University Cayetano Heredia (6.5% of Peruvian scientific production). There were 3,802 articles in Medline (1.2% were Peruvian), 35 in SciELO (94.3% were from Peru), and 168 in LILACS (11% were published in 2010-2014; only one article was published in 2015). Scientific production worldwide is led by the USA, and, in Latin America, by Peru and Brazil. However, Latin American scientific production in bibliographic databases is much lower than in other regions, despite being an endemic area for Carrion’s disease.

Concepts: United States, Spanish language, Spain, Brazil, South America, Americas, Latin America, Alexander von Humboldt


Emmanuelle Charpentier is a French microbiologist, geneticist and biochemist. She is a Director at the Max Planck Institute for Infection Biology in Berlin, Honorary Professor at Humboldt University, Visiting Professor at Umeå University and recipient of an Alexander von Humboldt Professorship. Prior to her current appointments, she worked at several other institutions in Germany, Sweden, Austria, the US and France. Emmanuelle Charpentier’s research on a bacterial immune system laid the foundation for the ground-breaking CRISPR-Cas9 genome engineering technology. She has received numerous prestigious awards and distinctions, and is an elected member of several renowned academies of sciences. She is co-founder of CRISPR Therapeutics and ERS Genomics.

Concepts: Bacteria, Germany, Max Planck, Alexander von Humboldt, Max Planck Society, Otto Hahn, Humboldt University of Berlin, Berlin


The catalog of type specimens of freshwater fishes deposited in the Colección de Peces Dulceacuícolas del Instituto de Investigación de Recursos Biológicos Alexander von Humboldt (IAvH-P) is presented. This list includes 483 specimens in 65 lots representing 11 holotypes and 472 paratypes of 48 nominal species. Corrections, additions, and updating of information in the original descriptions are included in individual remarks for each catalog number entry and a gallery of pictures of holotypes or paratypes of each nominal species is also presented, which supplements some original descriptions lacking figures of their respective types. An online version of the catalog is available at

Concepts: Biology, Botany, Freshwater fish, Charles Darwin, Type, Alexander von Humboldt, Simón Bolívar


Christian Behrends studied biology at the University of Konstanz in Germany, but did his Diploma thesis externally with Michael Ehrmann in the School of Bioscience at Cardiff University, UK. He then pursued his PhD degree in Franz-Ulrich Hartl’s group at the Max Planck Institute of Biochemistry in Martinsried, Germany. For his postdoctoral work Christian received a Feodor Lynen Research Fellowship from the Alexander von Humboldt Stiftung, with which he moved to the US and joined the laboratory of J. Wade Harper at Harvard Medical School. In 2011, he received an Emmy Noether Research Grant from the German Research Foundation (DFG) and started his own independent group at the Medical School of Goethe University in Frankfurt am Main. He is also a recipient of an ERC starting grant. Research in Christian’s lab is focused on the basic mechanisms of autophagy, particularly concentrating on the role of ubiquitin signalling in autophagy, and the crosstalk between autophagy and other vesicular trafficking pathways.

Concepts: Germany, Academic degree, Doctorate, Alexander von Humboldt, Max Planck Society, Humboldt University of Berlin, Frankfurt am Main, Munich


M. N. V. Ravi Kumar is interviewed by Stella Bennett, Commissioning Editor. He is the Professor at Department of Pharmaceutical Sciences, Texas A&M Health Science Center in College Station. His research in drug delivery has won him numerous awards including the British Pharmaceutical Conference Science Medal, UK (2009), Tom Gibson Memorial Award by British Society of Plastic Surgeons and the Royal College of Physicians and Surgeons, UK (2008), Indian National Science Academy (INSA) Medal for Young Scientist, India (2007). He was awarded Alexander von Humboldt Research Fellowship, Germany (2002). He was appointed to Guest Professor/Distinguished Foreign Professor at Seoul National University (South Korea); University of Navarra (Spain); University of Torino (Italy) and Shandong University, (China). Since 2003, he supervised about 41 students that include MS: 20; PhD: 7; Postdocs: 10 and Visitors: 4.

Concepts: Medicine, Science, University, South Korea, Award, Seoul National University, Alexander von Humboldt, National university