Natural Infections Caused by the Fungus <Emphasis Type="Italic">Beauveria bassiana</Emphasis> as a Pathogen of <Emphasis Type="Italic">Musca domestica</Emphasis>in the Neotropic

A survey for entomopathogenic fungi of Musca domestica adults was conducted in poultry houses in La Plata, Buenos Aires province, Argentina, during the years 2002 and 2003. Adult house flies were found infected with the fungus Beauveria bassiana (Bals.) Vuill. (Deuteromycotina: Hyphomycetes) from field collections, with a natural infected prevalence between 0.4–1.45%. This is the first record of natural infections of house flies caused by B. bassiana for the neotropics. Pathogenicity assays under laboratory conditions showed 94% adult mortality at 14 days post challenge. CIC fellow     

Resistance to freezing temperatures in Aedes (Ochlerotatus) albifasciatus (Macquart) eggs (Diptera: Culicidae) from two different climatic regions of Argentina

Aedes (Ochlerotatus) albifasciatus (Macquart) has the capacity to proliferate in different kinds of climates within its distribution range in South America. With the aim of studying local thermal adaptations of eggs, we exposed egg stocks from two climatically different localities: temperate humid pampa (Buenos Aires) and cold arid Patagonian (Sarmiento), to freezing conditions and then evaluated the effect on some features at this level. First, we thermally described the substrate where this species lays its eggs in the arid region. A typical thermal condition during winter was 10 h at ?12° C. Second, we evaluated the effect of freezing on primary hatching (vs total hatching) and embryo survival. We also compared the proportion of embryonated eggs from both populations. The proportions of embryonated eggs were not different between localities, with averages of 78% and 83% in Sarmiento and Buenos Aires, respectively. Survival was equally successful after freezing in the two localities with an average range between 94–99%. Whether or not the eggs from Buenos Aires and Sarmiento were under freezing conditions, hatching was more than 98% after the first flooding. The results suggest that eggs of Ae. albifasciatus from Sarmiento and Buenos Aires have the same ability to survive at extreme temperatures (<0° C), showing a regional thermal adaptation rather than a local one.     

COEVOLUTION AND AVIAN BROOD PARASITISM: COWBIRD EGGS SHOW EVOLUTIONARY RESPONSE TO HOST DISCRIMINATION

The Rufous Hornero (Furnarius rufus) is an important host of the brood parasitic Shiny Cowbird (Molothrus bonariensis) in Uruguay, but not in nearby Buenos Aires Province, Argentina. Eggs of the Shiny Cowbird are extremely variable in size, and horneros eject cowbird eggs with widths less than about 88% of the widths of their own eggs. Uruguayan cowbird eggs are, on average, 12% larger than those from Buenos Aires, a geographic pattern in egg size that corresponds to the pattern of successful host use. Uruguayan cowbird eggs are also wider per unit volume than eggs from Buenos Aires. Allometric analyses of egg width and volume indicate that this shape change is apparently an evolutionary response to selection exerted by the hornero. Such a response is absent in Buenos Aires because interactions between the cowbird and the hornero are probably of recent origin there.     

Plant communities and phytogeographical position of a large depression in the Great Chaco,Argentina

A survey is presented of the vegetation of the central region of the Santafesinian Chaco (Argentina), a scarcely populated flat area of 20 000 km², with seasonal flooding. Soils have a strong halo-hydromorphic character and vegetation is basically halophilous. Trees are scarce and most communities are savannas, grasslands or swampy vegetation. Twenty-three communities are described, some of them with several variants. The most widespread communities areSpartina argentinensis grasslands,Elyonurus muticus savannas and a complex of hygrophilous communities. The most important communities are distributed in relation to a topographical gradient, and their structure is shaped by recurrent flooding and fire disturbance. Most of the area is virgin land with very little human interference. The phytogeographical position of the area is discussed. Nomenclature: Burkart, A. 1969, 1974, 1979. Flora ilustrada de Entre Rios, INTA, Buenos Aires, and Cabrera, 1963, 1965a, b, 1967, 1968, 1970. Flora de la Provincia de Buenos Aires, INTA, Buenos Aires.     

An unconventional route to becoming a cell biologist

I am honored to be the E. B. Wilson Award recipient for 2015. As we know, it was E. B. Wilson who popularized the concept of a “stem cell” in his book The Cell in Development and Inheritance (1896, London: Macmillan & Co.). Given that stem cell research is my field and that E. B. Wilson is so revered within the cell biology community, I am a bit humbled by how long it took me to truly grasp his vision and imaginative thinking. I appreciate it deeply now, and on this meaningful occasion, I will sketch my rather circuitous road to cell biology.I grew up in a suburb of Chicago. My father was a geochemist, and for everyone whose parents worked at Argonne National Laboratories, Downers Grove was the place to live. My father’s sister was a radiobiologist and my uncle was a nuclear chemist, both at Argonne; they lived in the house next door. Across the street from their house was the Schmidtke’s Popcorn Farm—a great door to knock on at Halloween. The cornfields were also super for playing hide-and-seek, particularly when you happened to be shorter than those Illinois cornstalks.Open in a separate windowElaine FuchsI remember when the first road in the area was paved. It made biking and roller-skating an absolute delight. Fields of butterflies were everywhere, and with development came swamps and ponds filled with pollywogs and local creeks with crayfish. It was natural to become a biologist. When coupled with a family of scientists and a mother active in the Girl Scouts, all the resources were there to make it a perfect path to becoming a scientist.I could hardly wait until I was in junior high school, when I could enter science fairs. You would think that my science-minded family might help me choose and develop a research project. True to their mentoring ethos, they left these decisions to me. My first project was on crayfish behavior. I recorded the response of the crayfish I had caught to “various external stimuli.” At the end of this assault, I dissected the crayfish and, using “comparative anatomy,” attempted to identify all the parts. The second project was no gentler. I focused on tadpole metamorphosis and the effects of thyroid hormone in accelerating development at low concentrations and death at elevated concentrations. Somehow, I ended up going all the way to the state fair, where it became clear that I had serious competition. That experience, however, whetted my appetite to gain more lab experience and to learn to read the literature more carefully.My experience with high school biology prompted me to gravitate toward chemistry, physics, and math. When it came to college, my father told me that if there was a $2000/year (translated in 2015 to be $30,000/year) reason why I should go anywhere besides the University of Chicago (where Argonne scientists received a 50% tuition cut for their children) or the University of Illinois (then $200/year tuition), we could “discuss” it further. Having a sister, father, aunt, and uncle who went to the University of Chicago, I chose the University of Illinois and saved my Dad a bundle of money. At Illinois, I thought I might revisit biology, but my choices for a major were “biology for teachers” or “honors biology.” The first did not interest me; the second seemed intimidating.I enrolled as a chemistry major. Four years went by, during which time I never took a biology class. I enjoyed quantum mechanics, physics, and differential equations, and problem solving became one of my strengths. In the midst of the Vietnam War era, however, Illinois was a hotbed of activity. I was inspired to apply to the Peace Corps, with a backup plan to pursue science that would be more biomedically relevant than quantum mechanics. I was accepted to go to Uganda with the Peace Corps, but with Idi Amin in office, my path to science was clear. Fortunately, the schools I applied to accepted me, even though, in lieu of GRE scores, I had submitted a three-page essay on why I did not think another exam was going to prove anything. I chose Princeton’s biochemistry program. This turned out to be a great, if naïve choice, as only after accepting their offer did I take a biochemistry class to find out what I was getting into. I chose to carry out my PhD with a terrific teacher of intermediary metabolism, Charles Gilvarg, who worked on bacterial cell walls. My thesis project was to tackle how spores break down one cell wall and build another as they transition from quiescence to vegetative growth.By my fourth year of graduate school, I was trained as a chemist and biochemist and was becoming increasingly hooked on biomedical science. I listened to a seminar given by Howard Green, who had developed a method to culture cells from healthy human skin under conditions in which they could be maintained and propagated for hundreds of generations without losing their ability to make tissue. At the time, Howard referred to them as epidermal keratinocytes, but in retrospect, these were the first stem cells ever to be successfully cultured. I was profoundly taken by the system, and Howard’s strength in cell biology inspired me. It was the perfect match for pursuing my postdoctoral research. The time happened to be at the cusp of DNA recombinant technology.At MIT, I learned how to culture these cells. I wanted to determine their program of gene expression and how this changed when epidermal progenitors embark on their terminal differentiation program. While the problem in essence was not so different from that of my graduate work at Princeton, I had miraculously managed to receive my PhD without ever having isolated protein, RNA, or DNA. Working in a quintessential cell biology lab and tackling a molecular biology question necessitated venturing outside the confines of the Green lab and beyond the boundaries of my expertise. Fortunately, this was easy at MIT. Richard Hynes, Bob Horvitz, Bob Weinberg, and Graham Walker were all assistant professors, and their labs were very helpful, as were those of David Baltimore and Phil Sharp, a mere walk across the street. On the floor of my building, Steve Farmer, Avri Ben Ze’ev, Gideon Dreyfuss, and Ihor Lemischka were in Sheldon Penman’s lab just down the hall, and they were equally interested in mRNA biology, providing daily fuel for discussions. Uttam Rhajbandary’s and Gobind Khorana’s labs were also on the same floor, making it easy to learn how to make oligo(dT)-Sepharose to purify my mRNAs. Vernon Ingram’s lab was also on the same floor, so learning to make rabbit reticulocyte lysates to translate my mRNAs was also possible. Howard bought a cryostat, so I could section human skin and separate the layers. And as he was already working with clinicians at Harvard to apply his ability to create sheets of epidermal cells for the treatment of burn patients, I had access to the leftover scraps of human tissue that were also being used in these operations.The three years of my postdoc were accompanied by three Fuchs and Green papers. The first showed that epidermal keratinocytes spend most of their time expressing a group of keratin proteins with distinct sequences. The second showed that these keratins were each encoded by distinct mRNAs. The third showed that, as epidermal keratinocytes commit to terminally differentiate, they switch off expression of basal keratins (K5 and K14) and switch on the expression of suprabasal keratins (K1 and K10). That paper also revealed that different stratified tissues express the same basal keratins but distinct sets of suprabasal keratins. I am still very proud of these accomplishments, and my MIT experience made me thirst to discover more about the epidermis and its stem cells.My first and only real job interview came during my second year of postdoc, at a time when I was not looking for a job. I viewed the opportunity, initiated by my graduate advisor, as a free trip home to visit my parents and my trial run to prepare me for future searching. I was thrilled when this interview materialized into an offer to join the faculty, for which the University of Chicago extended my start time to allow me to complete my three years with Howard.Times have clearly changed, and it is painful to see talented young scientists struggle so much more today. That said, I have never looked ahead very far, and having a lack of expectations or worry is likely to be as helpful today as it was then. I am sure it is easier said than done, but this has also been the same for my science. I have always enjoyed the experiments and the joy of discovery. There was no means to an end other than to contemplate what the data meant in a broader scope.I arrived at the University of Chicago with a well-charted route. My aim was to make a cDNA library and clone and characterize the sequences and genes for the differentially expressed keratins I had identified when I was at MIT. It was three months into my being at Chicago when my chair lined up some interviews for me to hire a technician. I was so immersed in my science that I did not want to take time to hire anyone. I hired the first technician I interviewed. Fortunately, it worked out. However, I turned graduate students away the first year, preferring to carry out the experiments with my technician and get results. After publishing two more papers—one on the existence of two types of keratins that were differentially expressed as pairs and the other on signals that impacted the differential expression of these keratin pairs, I decided to accept a student, who analyzed the human keratin genes. My first postdoc was a fellow grad student with me at Princeton; she studied signaling and keratin gene expression. My second postdoc was initiated by my father, who chatted with him at the elevator when I was moving into my apartment. He set up DNA sequencing and secondary-structure prediction methods, and the lab stayed small, focused, and productive.I was fascinated by keratins, how they assembled into a network of intermediate filaments (Ifs). When thalassemias and sickle cell anemia turned out to be due to defects in globin genes, I began to wonder whether there might be human skin disorders with defective keratin genes. I had no formal training in genetics, and there were no hints of what diseases to focus on. Thus, rather than using positional cloning to identify a gene mutation associated with a particular disease, we took a reverse approach: we first identified the key residues for keratin filament assembly. After discovering that mutations at these sites acted dominant negatively, we engineered transgenic mice harboring our mutant keratin genes and then diagnosed the mouse pathology. Our diagnoses, first for our K14 mutations and then for our K10 mutations, turned out to be correct: on sequencing the keratins from humans with epidermolysis bullosa simplex (EBS), we found K14 or K5 mutations; similarly, we found K1 or K10 mutations in affected, but not in unaffected, members of families with epidermolytic hyperkeratosis (EH). Both are autosomal-dominant disorders in which patients have skin blistering or degeneration upon mechanical stress. Without a proper keratin network, the basal (EBS) or suprabasal (EH) cells could not withstand pressure. Ironically, family sizes of all but the mildest forms of these disorders were small, meaning that the disorders were not amenable to positional cloning. But the beauty of this approach is that once we had made the connection to the diseases, we understood their underlying biology. In addition, the IF genes are a superfamily of more than 100 genes differentially expressed in nearly all tissues of the body. Once we had established EBS as the first IF gene disorder, the pathology and biology set a paradigm for a number of diseases of other tissues that turned out to be due to defects in other IF genes.Fortunately, I had students, Bob Vassar (professor, Northwestern University) and Tony Letai (associate professor, Harvard Medical School), and a postdoc, Pierre Coulombe (chair, Biochemistry and Molecular Biology, Johns Hopkins University), who jumped into this fearless venture with me. We had to go off campus to learn transgenic technology. I had never worked with mice before. When Bob returned to campus with transgenic expertise, we hired and trained Linda Degenstein, whose love for animal science was unparalleled. Pierre’s prior training in electron microscopy was instrumental in multiple ways. Additionally, I was not a dermatologist and had no access to human patients. Fortunately Amy Paller, MD, at Northwestern volunteered to work with us.The success of this project attests to an important recipe: 1) Pursue a question you are passionate about. 2) In carrying out rigorous, well-controlled experiments, each new finding should build upon the previous ones. 3) If you have learned to be comfortable with being uncomfortable, then you will not be afraid to chart new territory when the questions you are excited to answer take an unanticipated turn. 4) Science does not operate in a vacuum. Interact well with your lab mates and take an interest in their science as well as your own. And wherever you embark upon a pathway in which the lab’s expertise is limited, do not hesitate to reach out broadly to other labs and universities.I have followed this recipe now for more than three decades, and it seems to work pretty well. A lab works only when its students and postdocs are interactive, naturally inquisitive, and freely share their ideas and findings. I have been blessed to have a number of such individuals in my lab over the years. When push comes to shove, I am always inclined first to shave from the “brilliant” category and settle for smart, nice people who are passionate and interactive about science and original and unconventional in their thinking.So what questions have I been most passionate about? I have always been fascinated with how tissues form during development, how they are maintained in the adult, and how tissue biology goes awry in human disorders, particularly cancers. I first began to think about this problem during my days at Princeton. I also developed a dogma back then that I still hold: to understand malignancies, one must understand what is normal before one can appreciate what is abnormal. I think this is why I have spent so much of my life focusing on normal tissue morphogenesis, despite my passion for being at the interface with medicine. And because skin has so many amazingly interesting complexities, and because it is a great system to transition seamlessly between a culture dish and an animal, I have never found a reason to choose any other tissue over the one I chose many years back.I will not dwell on the various facets of skin biology we have tackled over the years. Our initial work on keratins was to obtain markers for progenitors and their differentiating lineages. This interest broadened to understanding how proliferative progenitors form cytoskeletal networks and how the cytoskeleton makes dynamic rearrangements during tissue morphogenesis.From the beginning, the lab has also been fascinated by how tissue remodeling occurs in response to environmental signals. Indeed, signals from the microenvironment trigger changes in chromatin dynamics and gene expression within tissue stem cells. Ultimately, this leads to changes in proteins and factors that impact on cell polarity, spindle orientation, asymmetric versus symmetric fate specifications, and ultimately, the balance between proliferation and differentiation.The overarching theme of my lab over these decades is clear, namely, to understand the signals that unspecified progenitors receive that instruct them to generate a stratified epidermis, make hair follicles, or make sweat and sebaceous glands. And if we can understand how this happens, then how are stem cells born, and how do they replace dying cells or regenerate tissue after injury? And, finally, how does this process change during malignant progression or in other aberrant skin conditions?In tackling tissue morphogenesis, I have had to forgo knowing the details of each tree and instead focus on the forest. There are many times when I stand back and can only admire those who are able to dissect beautiful cellular mechanisms with remarkable precision. But I crossed that bridge some years ago in tackling a problem that mandates an appreciation of nearly all the topics covered in Bruce Alberts’ textbook Molecular Biology of the Cell. I am now settled comfortably with the uncomfortable, and the problem of tissue morphogenesis in normal biology and disease continues to keep me more excited about each year’s research than I was the previous year. Perhaps the difference between my days as a student, postdoc, and assistant professor and now is that my joy and excitement is as strong for those I mentor and have mentored as it is for myself.     

Life in a Three-dimensional Grid

There have been two sharp demarcations in my life in science: the transition from fine arts to chemistry, which happened early in my career, and the move from New York to Stanford University, which initiated an ongoing collaboration with the physicist Harley McAdams. Both had a profound effect on the kinds of questions I posed and the means I used to arrive at answers. The outcome of these experiences, together with the extraordinary scientists I came to know along the way, was and is an abiding passion to fully understand a simple cell in all its complexity and beauty.     

Phylogeny of the tribe Colletieae (Rhamnaceae) – a sensitivity analysis of the plastid region trnL-trnF combined with morphology

The phylogenetic relationships within the tribe Colletieae (Rhamnaceae) were examined combining data from a previous morphological analysis with data from the trnL intron and trnL-F spacer. Previous studies have failed to confirm monophyly of the genus Discaria, the only genus of the tribe with an amphiantarctic distribution. The data set was analyzed using direct optimization as implemented in the computer program POY. Direct optimization searches for multiple optimal sequence alignments and is therefore well suited for analyzing DNA sequences including ambiguous alignable regions as found in the present study. Eight different costs were used for treating the indel information. Indels were treated as single events, equal to a fifth character state, or strings of gaps were treated as single events using different costs for opening a gap and extending the gap. The optimal cost set was selected by use of both character-based and topological congruence measures. Both congruence measures agreed upon a single optimal cost set. The resulting tree generally agrees with the current taxonomic treatment of the tribe Colletieae that recognizes six genera out of which three are monotypic. However, monophyly of Discaria was not supported and the results strongly suggest segregating D. nana and D. trinervis, and re-establishing the genus Ochetophila.We are grateful to the curator of the Herbario Gaspar Xuárez, Universidad de Buenos Aires (BAA), and to the curators of the Botanic Garden of the University of Copenhagen, Botanischer Garten und Botanisches Museum Berlin-Dahlem, Jardín Botánico Lucien Hauman (Facultad de Agronomía de la Universidad de Buenos Aires), Rancho Santa Ana Botanic Garden, and Royal Botanic Gardens, Melbourne, for permission to use material from their collections. María Elena Arce, María Martha Bianchi, Eugenia Chaia, and Neville Walsh kindly provided freshly collected material. We also thank Pablo A. Goloboff, Niels Klazenga, Pauline Y. Ladiges, Martín Ramírez, Ole Seberg, Llywela Williams, and two anonymous reviewers for critically reading earlier drafts of this paper. This work was supported in part by grants TG 028 (Universidad de Buenos Aires) and PIP 4027/96 (CONICET) to D. Medan. The University of Copenhagen supported Lone Aagesen (Ph.D. grant). Jürgen Kellermann received a Ph.D.-scholarship from the University of Melbourne.     

On the taxonomic status of a Dugesia species from Buenos Aires (Platyhelminthes: Turbellaria: Tricladida)

The taxonomic and distributional statuses of the freshwater planarians of South America are imperfectly understood, and a comprehensive review is sorely needed. The species known from the vicinity of Buenos Aires, Argentina, was first described by Böhmig (1902) under the name Planaria dubia Borelli, 1895. Subsequent authors (Kenk, 1930, 1974; Cazzaniga & Curino, 1987) have cast doubt on this assignation. Some have assigned it to Dugesia anceps Kenk; Hyman (1959) was inclined to regard the Buenos Aires planarian as a geographical variant of Dugesia sanchezi Hyman. A comparison of D. sanchezi from the mountainous region of central Chile with specimens from Buenos Aires confirms that the Argentinian material is a distinct species.The differences between the two species are subtle. The Argentinian specimens are distinctive in their possession of infranucleate epithelia of the atria, penis, and bursal canal, as well as in their penial structure. In both species, the epithelia of the atria and bursal canal are glandular. Those of D. sanchezi are nucleate and their secretions are cyanophilous. In the Argentinian specimens, these same epithelia are infranucleate; but while the secretion of the bursal canal is indeed cyanophilous, that of the atrium is erythrophilous. The presence, in these same specimens, of cyanophilous glands opening into the penial vesicles, and of erythrophilous glands whose secretions contribute to a viscous plug in the ejaculatory duct, suggests a difference in the physiology of copulation.It is apparent that the Argentinian specimens are distinct from D. sanchezi Hyman, and probably they represent a new species, one to be described in detail elsewhere. In any case, Hyman's (1959) suggestion that D. sanchezi occurs near Buenos Aires is mistaken; so also is Cazzaniga's & Curino's (1987) identification of specimens from Buenos Aires as D. anceps.     

Gene frequencies in the cat population of Buenos Aires, Argentina, and the possible origin of this population.

The phenotypes of 295 stray cats seen in the capital area of Buenos Aires, Argentina, between March and December of 1989 were recorded. The corresponding mutant allele frequencies were as follows: O = 0.28, a = 0.83, Ta = 0.01; tb = 0.31; d = 0.45; I = 0.40; S = 0.28; W = 0.02. The allele frequencies calculated at the O locus were consistent with those expected for a randomly breeding population according to the formula for the Hardy-Weinberg equilibrium. The analysis of the genetic distances between Buenos Aires and several European cat populations revealed that the Spanish and, especially, those with a proven more ancestral genetic constitution, are the most closely related. When a similar analysis was carried out, including other Latin American cat populations, those of Spanish origin were found to show the highest degree of relatedness. These findings suggest that the Buenos Aires cat population was not genetically structured following the "two-stepping-stone" model and support the hypothesis that differential gene flows play a transcendental role in understanding the genetic composition of domestic cat populations.     

Rickettsia spp., Ehrlichia sp. and Candidatus Midichloria sp. associated to ticks from a protected urban area in Buenos Aires City (Argentina)

The aim of this study was to determine the infection with Rickettsiales in ticks and birds from the main protected urban area of Buenos Aires City (Argentina). One Amblyomma aureolatum (0.2%) and one Ixodes auritulus (0.1%) were positive by PCR targeting Rickettsia 23S-5S rRNA intergenic spacer. Phylogenetic analysis shows to findings in A. aureolatum are closely to Rickettsia bellii and for I. auritulus are related to ‘Candidatus Rickettsia mendelii’. One I. auritulus (0.1%) and three A. aureolatum (0.6%) were positive by PCR for a fragment of the 16S rRNA gene of the Anaplasmataceae family. The sequences obtained from A. aureolatum were phylogenetically related to Midichloriaceae endosymbionts. The sequence from I. auritulus s.l. had 100% identity with Ehrlichia sp. Magellanica from Chile and two genotypes of Ehrlichia sp. from Uruguay. The results of our study show that Rickettsia and Ehrlichia are present in ticks in the main protected urban area of Buenos Aires City.

     

Tayassu pecari (Link, 1795) (Mammalia,Cetartiodactyla): comments on its South American fossil record,taxonomy and paleobiogeography

Tayassu pecari is widely distributed across the Neotropical region, from northern Argentina to south-eastern Mexico. However, its fossil record is scarce; it is recorded since the middle Pleistocene to Holocene in Argentina, Brazil and Uruguay. This paper aims to: (1) update the systematic synonymy of this species; (2) review and update its geographic chronologic distribution and provide a new Lujanian record of Tayassu pecari in Buenos Aires Province and (3) discuss the paleoenvironmental and paleobiogeographical implications of this record. Considering the quantitative analysis performed, the fossil here recorded clearly integrates the group of Tayassu pecari. This specimen corresponds to the first record of Tayassu pecari in the central-northern region of the Buenos Aires Province. During Late Pleistocene, Tayassu pecari was distributed southern to its recent range, probably evidencing different paleoenvironment conditions. This species is the better adapted peccary to tropical and subtropical rainforests, but may also be present in arid environments. Consequently, Tayassu by itself is insufficient to infer the prevailing environmental conditions. However, according to the fauna associated with the specimen described here, it is possible to infer an open or semi-open and arid or semi-arid environment for the central-northern Buenos Aires region by Late Pleistocene times.     

African ancestry of the population of Buenos Aires

The population of Argentina today does not have a “visible” black African component. However, censuses conducted during most of the 19th century registered up to 30% of individuals of African origin living in Buenos Aires city. What has happened to this African influence? Have all individuals of African origin died, as lay people believe? Or is it possible that admixture with the European immigrants made the African influence “invisible?” We investigated the African contribution to the genetic pool of the population of Buenos Aires, Argentina, typing 12 unlinked autosomal DNA markers in a sample of 90 individuals. The results of this analysis suggest that 2.2% (SEM = 0.9%) of the genetic ancestry of the Buenos Aires population is derived from Africa. Our analysis of individual admixture shows that those alleles that have a high frequency in populations of African origin tend to concentrate among 8 individuals in our sample. Therefore, although the admixture estimate is relatively low, the actual proportion of individuals with at least some African influence is approximately 10%. The evidence we are presenting of African ancestry is consistent with the known historical events that led to the drastic reduction of the Afro‐Argentine population during the second half of the 19th century. However, as our results suggest, this reduction did not mean a total disappearance of African genes from the genetic pool of the Buenos Aires population. Am J Phys Anthropol 128:164‐170, 2005. © 2005 Wiley‐Liss, Inc.     

The evolution of a cell biologist

I am honored and humbled to receive the E. B. Wilson Medal and happy to share some reflections on my journey as a cell biologist. It took me a while to realize that my interest in biology would center on how cells are spatially and dynamically organized. From an initial fascination with cellular structures I came to appreciate that cells exhibit dynamism across all scales—from their molecules, to molecular complexes, to organelles. Uncovering the principles of this dynamism, including new ways to observe and quantify it, has been the guiding star of my work.

Jennifer Lippincott-Schwartz     

Observation of leaf-cutting ants foraging on wild mushrooms

This study reports on the observation of an unusual behavior in leaf-cutting ants: foraging on wild mushrooms. A colony of Acromyrmex lundi in Buenos Aires (Argentina) was observed intensively harvesting basidiomes (mushroom fructifications) of wild Agrocybe fungus developing on a tree bark. Another colony maintained for a month in laboratory conditions also accepted Agrocybe mushroom and incorporated the cut bits into the fungus garden in the same way as they do with leaves. We recorded these events confident that they open a new perspective on the study of the feeding habits of leaf-cutting ants as well as on the relationship between their fungus garden and other organisms.     

Notes on ciliates (Protozoa,ciliophora) from Espeletia trees and Espeletia soils of the Andean Páramo,with descriptions of sikorops espeletiae nov. spec. and Fragmocirrus espeletiae nov. gen., nov. spec.

Melittobia hawaiiensis Perkins (Hymenoptera: Eulophidae), a common gregarious ectoparasitoid of aculeate Hymenoptera and other orders of insects, is reported for the first time as a parasitoid of Melitoma segmentaria (Fabricius) (Hymenoptera: Apidae) in Buenos Aires, Argentina.     

Thermal response in pre‐imaginal biology of Ochlerotatus albifasciatus from two different climatic regions

The biological processes on mosquito could be variable in response to local climatic characteristics. The thermal effects on time and the rate larval development, immature survival and adult size in local populations of Ochlerotatus albifasciatus (Macquart) (Diptera: Culicidae) from cold (Sarmiento) and temperate (Buenos Aires) regions from Argentina were evaluated. This species affects livestock production and human health. Larvae of both regions were placed in breeding thermal baths (11–32 °C range). Development and survival were recorded daily until adult emergence. The development temperature threshold and thermal constant for Sarmiento (4.59 ± 3.08 °C, 204.08 ± 7.83 degree days) was lower and higher than Buenos Aires, respectively (8.06 ± 1.81 °C, 149.25 ± 2.6 degree days). At cold temperatures (11–16 °C), Sarmiento larvae demonstrated 5 days faster development and higher survival (56%) than Buenos Aires (15%), whereas at warm temperatures (20–32 °C) were up to 2 days slower and similar survival (16% vs. 18%). The size did not show differences between populations. An Ochlerotatus albifasciatus population seems to present local thermal responses. The favourable temperature for survival and rate of development would vary within a cold or warm range, and these differential responses would explain the wide geographical distribution in different climatic regions of southern South America.     

Sociobiology and the Comparative Approach: One Way to Study Ourselves

This paper is based on my lecture in a macroevolution course I team-teach with Profs. Daniel Brooks and David Evans at the University of Toronto. The lecture has undergone many revisions over the years as I grappled with problems discussing certain areas (e.g., rape as an adaptive strategy, gender “roles”). Eventually, I realized that the problem areas said more about my personal conflicts than they did about the science. This was one of those epiphany moments, a time when I recognized that I was less likely to accept hypotheses that contradicted the way I wanted the world to be and more likely to uncritically accept hypotheses that confirmed my world view. That epiphany, in turn, led me to realize that science is never separate from the personal biases/demons of its practitioners, especially when we are asking questions about the evolution of human behavior. That realization was not novel within the vast literature of sociology and philosophy. But it was novel for me. I was aware of discussions about personal biases clouding scientific interpretation; I just didn’t think it applied to me (I absorbed the philosophical discussions without making the connection to “my world”). So, on the heels of that epiphany, the following is a very personal take on the question of teaching sociobiology, based on where my journey, aided by my experience as an ethologist and phylogeneticist and colored by my own history, has taken me.     

You are the most valuable reagent in the lab: mental health before and during the pandemic

No one maps out their tenure as a postdoc anticipating a life-altering tragedy. But mental health crises of all kinds affect academic trainees and staff at similar or higher levels than the general public. While the mental health resources available to trainees are often set by healthcare providers, all levels of university leadership can work to remove material and immaterial obstacles that render such resources out of reach. I describe how access to care via telemedicine helped me following a loss in my family.

Over the years, my siblings and close friends have sought mental health resources like therapy, psychoanalysis, or psychiatry, so I loosely understood their benefits. When I was a PhD student I went to therapy briefly, but my counselor and I decided I could do without it. Since I started my postdoc, stress manifested in some new ways but I managed it well with my usual coping strategies and support. That changed one bright December morning in 2019 while I was preparing for our weekly lab meeting. My phone rang indicating a call from my father, whom I had spoken to the night before to celebrate the news of my nephew’s birth. But the voice on the phone was that of a family friend, telling me that my father had died overnight of an undiagnosed heart condition. In the moment I couldn’t even understand what was happening, saying over and over, “but I talked to him last night.” Soon I was sitting at home, dazed, on a string of tearful calls with family and friends.I often read words like “lifted” or “buoyed” to describe the stabilizing support of a network of loved ones. In my case this network was tethering me to reality over the next few weeks, preventing me from spinning off the Earth’s surface in a storm of sorrow and anxiety. The trauma also took a strange physical form and convinced me that I was suffering from a cardiac condition of my own. I had a panic attack during which I went to urgent care convinced my own heart was about to give way. Night after night these physical symptoms prevented me from sleeping.Graced by many loving connections with my siblings, my boyfriend, and close friends, I was actually weathering the process as well as one can. My PI gave me a firm directive to take as much time off as I needed. These were two key elements early in my healing process: a supportive network and an understanding advisor. The third was getting professional help, which I soon realized I needed. Even if I felt OK one day, I didn’t trust that I’d be OK the next. My grief formed too thick and too broad a landscape for me to navigate without help.Deciding to seek mental health resources and realizing that one needs them are often the hardest parts. Connecting with those resources once the decision has been made should be as simple as possible. I called a mental health number, and a triage counselor noted my therapy needs and verified my insurance. She asked what times and locations I preferred and then searched for an open appointment with a therapist who accepted my insurance. She also informed me that my coverage allowed 12 sessions with no copay, which was a pleasant surprise. The therapist who agreed to see me had very few openings, in part because this all happened in December—the holidays are especially busy for therapists. I was aiming for a time after normal working hours, or in the morning before I would head to lab, but none of those times were available. I didn’t like interrupting my workday to trot off to therapy. Taking a long break once a week meant I couldn’t run experiments or mentor my student during that time. But I made the sacrifice because my highest priority was getting the help I needed. There was no shortcut. Prioritizing mental health over lab work is tough for researchers, and I would never have accepted that kind of weekly disruption before my dad’s passing. But as a wonderful mentor of mine used to say, “You are the most valuable reagent in the lab.” She wasn’t describing mental health at the time, but the phrase now provided a guiding principle for my recovery. My first few sessions were on Tuesdays at 2:00 pm.The afternoon break turned out to be less disruptive than I had feared, because I had recently come back to the lab and was working short days. Had she asked, I would have told my PI where I was on Tuesday afternoons, but she wasn’t normally abreast of my daily schedule, so I didn’t seek her approval beforehand. Coordinating experiments with lab members thankfully wasn’t an issue because my work was largely independent; I simply let lab members know that I’d would be out of the lab for a bit on those days.The weeks went by, and the benefits of therapy accrued, helping me in large and small ways as I grieved. In mid-March of 2020, my therapist followed public health guidelines and asked all her clients to transition to remote sessions. While this was easy and sensible, it was still a little disappointing. Therapists are professional empaths, among many other things, and doing away with the physical presence and exchange with her was a blow. Yet therapy via video felt less odd simply because most of my social interactions were now virtual. Thankfully I didn’t have to move out of state for the lockdown (as did many students living in campus housing), which meant I could stay with the same therapist without any insurance complications.A few weeks into lockdown, I asked my therapist whether we had reached the limit of my 12 sessions without a copay. She replied with the good news that my insurance provider had waived all copays for mental health costs due to the pandemic. By that time therapy had generated a platform and an outlet to explore areas of my grief beyond the trauma of my father’s passing. Without needing to weigh the costs and benefits of this resource, I saw my therapist for another 4 months. I slowly took stock of my upbringing in an unconventional family and the loss of my mother when I was 25 and waded through a series of difficult decisions regarding my father’s estate. My father’s death changed me at a depth that is untouched by any amount of therapy or treatment. I’m not “healed”: I feel aged, more brittle, and a little ground down compared with who I had been. But therapy guided me through the worst of my grief, past the acute trauma to help me grasp what I was going through.Since the pandemic began, the number of people reporting increased stress or mental health issues has steadily increased (information on the impact of COVID-19 measures on mental health: https://www.apa.org/workforce/publications/depression-anxiety-coronavirus.pdf) (also see Mental health resources for trainees). I am fortunate to have affordable health insurance and the support from my lab and my department. The ease of finding my institution’s phone number for mental health resources was itself an important benefit. I share these pieces of my story with humility and understanding that not everyone enjoys the privileges that I do and the knowledge that everyone weathers life’s tragedies in their own way. It is not lost on me that some benefits stemmed from a policy change made by a private insurance provider. The provider made the right decision to waive copays, freeing me from having to choose between cost and my mental health needs. Yet had I been a student who had to move out of state due to COVID-19, access to mental health resources might have been disrupted or cut off. The need for reduced out-of-pocket costs for healthcare is known and needs no repetition, but the benefits of telehealth should be a low-cost component of health plans offered to students and staff (information on telehealth recommendations: https://www.apaservices.org/advocacy/news/congress-patient-telehealth?_ga=2.231013471.1538013741.1619359426-1228006513.1619359425 and http://www.apaservices.org/practice/advocacy/state/leadership/telebehavioral-health-policies.pdf?_ga=2.3385904.1067518037.1620039082-1228006513.1619359425.I’m not a cloud of emotions attached to a pair of good pipetting hands, I’m a human who is choosing to spend my time doing research. This observation is easy to repeat, by trainees as much as by faculty and administrators, but much harder to act upon in the midst of conflicting priorities. Consider my story a success: Because I could access the resources I needed, I was able to prioritize my mental health in the midst of my ambitious research program even during the lockdown.MEET THE AUTHORI have been a postdoc in Stefani Spranger’s lab at MIT for 4 years. Supported by an Irvington Fellowship from the Cancer Research Institute, my work examines the behaviors of dendritic cells in tumors that contribute to productive or unproductive anti-tumor immune responses. My doctoral work examined modes of multicellular invasion controlled by the actin cytoskeleton with Margaret Gardel at the University of Chicago. Earlier I was a lab technician with Thea Tlsty at the University of California, San Francisco, which followed a bachelor’s degree in biology at the University of California, Santa Cruz. I serve on the Committee for Students and Postdocs at the American Society for Cell Biology, where I chair the Outreach Subcommittee.     

Length–weight relationships for three small reef‐fishes from the Argentine coast: Helcogrammoides cunninghami (Smitt, 1898), Ribeiroclinus eigenmanni (Jordan, 1888), and Hypleurochilus fissicornis (Quoy and Gaimard, 1824)

In this study the first length–weight relationships are provided for Helcogrammoides cunninghami and Ribeiroclinus eigenmanni inhabiting subtidal rocky areas in northern Patagonia, and for Hypleurochilus fissicornis inhabiting intertidal rocky areas in Buenos Aires Province. Specimens were collected between 2009 and 2016, from seven different locations in northern Patagonia and Buenos Aires Province (Southwest Atlantic Coast; 37°–42°S), using a trawling dredge or a small hand net. New maximum lengths were recorded for R. eigenmanni and H. fissicornis.     

First record of Huarpea wagneriella (Hymenoptera: Sapygidae) as a cleptoparasite of large carpenter bees (Hymenoptera: Apidae,Xylocopinae)

The species Huarpea wagneriella (Hymenoptera: Sapygidae), a cleptoparasite of nests of bees of the genera Xylocopa Latreille and Megachile Latreille (Hymenoptera: Apoidea), is reported for the first time as a cleptoparasite of Xylocopa ciliata Burmeister (Hymenoptera: Apidae) in Buenos Aires, Argentina. Biological notes on species of Xylocopa and a morphological characterization of Huarpea are given.