Eijkman, Christiaan (1858-1930) Dutch Physician Christiaan Eijkman was born on August 11, 1858, at Nijkerk in Gelderland (The Netherlands) to Christiaan Eijkman, the headmaster of a local school, and Johanna Alida Pool. He received his education at his father’s school in Zaandam. In 1875 he entered the Military Medical School of the University of Amsterdam and received training as a medical officer for the Netherlands Indies Army. From 1879 to 1881 he wrote his thesis "On Polarization of the Nerves," which gained him his doctor’s degree, with honors, on July 13, 1883. On a trip to the Indies he caught malaria and returned to Europe in 1885.
Eijkman was director of the Geneeskundig Labora-torium (medical laboratory) in Batavia from 1888 to 1896, and during that time he made a number of important researches in nutritional science. In 1893 he discovered that the cause of beriberi was a deficiency of vitamins and not, as thought by the scientific community, of bacterial origin. He discovered vitamin B, and this discovery led to the whole concept of vitamins. For this discovery he was awarded the Nobel Prize in physiology or medicine for 1929.
He wrote two textbooks for his students at the Java Medical School, one on physiology and the other on organic chemistry.
In 1898 he became a professor of hygiene and forensic medicine at utrecht, but he also engaged in problems of water supply, housing, school hygiene, and physical education. As a member of the Gezond-heidsraad (health council) and the Gezondheids Com-missie (health commission), he participated in the struggle against alcoholism and tuberculosis. He was also the founder of the Vereeniging tot Bestrijding van de Tuberculose (Society for the struggle against tuberculosis). Eijkman died in Utrecht on November 5, 1930.
Eijkman’s syndrome, a complex of nervous symptoms in animals deprived of vitamin B1, is named for him.
Einthoven, Willem (1860-1927) Dutch Physiologist Willem Einthoven was born on May 21, 1860, in Semarang on the island of Java, Indonesia, to Jacob Einthoven, an army medical officer in the Indies, and Louise M. M. C. de Vogel, daughter of the then-director of finance in the Indies.
Upon the death of his father, Einthoven and his family moved to Holland and settled in Utrecht, where he attended school. In 1878 he entered the University of Utrecht as a medical student. In 1885, after receiving his medical doctorate, he was appointed successor to A. Heynsius, professor of physiology at the University of Leiden, where he stayed until his death.
He conducted a great deal of research on the heart. To measure the electric currents created by the heart, he invented a string galvanometer (called the Einthoven galvanometer) and was able to measure the changes of electrical potential caused by contractions of the heart muscle and to record them by creating the electrocardiograph (EKG), a word he coined. The EKG provides a graphic record of the action of the heart. This work earned him the Nobel Prize in physiology or medicine for 1924. He published many scientific papers in journals of the time. He died on September 29, 1927.
Electrochemical gradient The relative concentration of charged ions across a membrane. Ions move across the membrane due to the concentration difference on the two sides of the membrane as well as the difference in electrical charge across the membrane.
Electrode potential Electrode potential of an electrode is defined as the electromotive force (emf) of a cell in which the electrode on the left is a standard hydrogen electrode and the electrode on the right is the electrode in question.
Electrogenic pump Any large, integral membrane protein (pump) that mediates the movement of a substance (ions or molecules) across the plasma membrane against its energy gradient (active transport). The pump, which can be ATP-dependent or Na+-dependent, moves net electrical charges across the membrane.
Electromagnetic spectrum The entire spectrum of radiation arranged according to frequency and wavelength that includes visible light, radio waves, microwaves, infrared, ultraviolet light, x rays, and gamma rays. Wavelengths range from less than a nanometer, i.e., X and gamma rays (1 nanometer is about the length of 10 atoms in a row), to more than a kilometer, i.e., radio waves. Wavelength is directly related to the amount of energy the waves carry. The shorter the radiation’s wavelength, the higher its energy. Frequencies of the electromagnetic spectrum range from high (gamma rays) to low (AM radio). All electromagnetic radiation travels through space at the speed of light, or 186,000 miles (300,000 km) per second.
Electron A negatively charged subatomic particle of an atom or ion.
Electron acceptor A substance that receives electrons in an oxidation-reduction reaction.
Electronegativity Each kind of atom has a certain attraction for the electrons involved in a chemical bond. This attraction can be listed numerically on a scale of electronegativity. Since the element fluorine has the greatest attraction for electrons in bond-forming, it has the highest value on the scale. Metals usually have a low electronegativity, while nonmetals usually have high electronegativity. When atoms react with one another, the atom with the higher electronegativity value will always pull the electrons away from the atom that has the lower electronegativity value.
Electron microscope (EM) A very large tubular microscope that focuses a highly energetic electron beam instead of light through a specimen, resulting in a resolving power thousands of times greater than that of a regular light microscope. A transmission EM (TEM) is used to study the internal structure of thin sections of cells, while a scanning EM (SEM) is used to study the ultrastructure of surfaces. The transmission electron microscope, the first type of electron microscope, was developed in 1931 by Max Knoll and Ernst Ruska in Germany and was patterned exactly on the light transmission microscope except that it used a focused beam of electrons instead of light to see through the specimen. The first scanning electron microscope was built in 1942, but it was not available commercially until 1965.
Electron-nuclear double resonance (ENDOR) A magnetic resonance spectroscopic technique for the determination of hyperfine interactions between electrons and nuclear spins. There are two principal techniques. In continuous-wave ENDOR, the intensity of an electron paramagnetic resonance signal, partially saturated with microwave power, is measured as radio frequency is applied. In pulsed ENDOR the radio frequency is applied as pulses and the EPR signal is detected as a spin-echo. In each case an enhancement of the EPR signal is observed when the radio frequency is in resonance with the coupled nuclei.
Electron paramagnetic resonance (EPR) spectroscopy The form of spectroscopy concerned with microwave-induced transitions between magnetic energy levels of electrons having a net spin and orbital angular momentum. The spectrum is normally obtained by magnetic-field scanning. Also known as electron spin-resonance (ESR) spectroscopy or electron magnetic resonance (EMR) spectroscopy. The frequency (v) of the oscillating magnetic field to induce transitions between the magnetic energy levels of electrons is measured in gigahertz (GHz) or megahertz (MHz). The following band designations are used: L (1.1 GHz), S (3.0 GHz) , X (9.5 GHz), K (22.0 GHz), and Q (35.0 GHz). The static magnetic field at which the EPR spectrometer operates is measured by the magnetic flux density (B), and its recommended unit is the tesla (T). In the absence of nuclear hyperfine interactions, B and v are related by: h v = g^BB, where h is the Planck constant, |B is the Bohr magneton, and the dimensionless scalar g is called the g-factor. When the paramagnetic species exhibits an anisotropy, the spatial dependency of the g-factor is represented by a 3 X 3 matrix. The interaction energy between the electron spin and a magnetic nucleus is characterized by the hyperfine coupling constant A. When the paramagnetic species has anisotropy, the hyperfine coupling is expressed by a 3 X 3 matrix called a hyperfine-coupling matrix. Hyperfine interaction usually results in splitting of lines in an EPR spectrum. The nuclear species giving rise to the hyperfine interaction should be explicitly stated, e.g., "the hyperfine splitting due to 65Cu." When additional hyperfine splittings due to other nuclear species are resolved ("superhyperfine"), the nomenclature should include the designation of the nucleus and the isotope number.
Electron spin-echo (ESE) spectroscopy A pulsed technique in electron paramagnetic resonance, in some ways analogous to pulsed techniques in NMR (nuclear magnetic resonance spectroscopy). ESE can be used for measurements of electron spin relaxation times, as they are influenced by neighboring para-magnets or molecular motion. It can also be used to measure anisotropic nuclear hyperfine couplings. The effect is known as electron spin-echo envelope modulation (ESEEM). The intensity of the electron spin-echo resulting from the application of two or more microwave pulses is measured as a function of the temporal spacing between the pulses. The echo intensity is modulated as a result of interactions with the nuclear spins. The frequency-domain spectrum corresponds to hyperfine transition frequencies.
Electron-transfer protein A protein, often containing a metal ion, that oxidizes and reduces other molecules by means of electron transfer.
Electron-transport chain A chain of electron acceptors embedded in the inner membrane of the mitochondrion. These acceptors separate hydrogen protons from their electrons. When electrons enter the transport chain, the electrons lose their energy, and some of it is used to pump protons across the inner membrane of the mitochondria, creating an electrochemical gradient across the inner membrane that provides the energy needed for ATP (adenosine triphosphate) synthesis. The function of this chain is to permit the controlled release of free energy to drive the synthesis of ATP.
Element A substance consisting of atoms that have the same number of protons in their nuclei. Elements are defined by the number of protons they possess.
Elephantiasis (lymphedema filariasis) A visibly grotesque enlargement and hardening of the skin and subcutaneous tissues, usually in the leg or region of the testis, caused by obstruction of the lymphatic system when the lymph node is infested by the nematode worm, Wuchereria bancrofti.
Elimination The process achieving the reduction of the concentration of a xenobiotic compound, including its reduction via metabolism.
Embryo The resulting organism that grows from a fertilized egg following rapid development and eventually becomes an offspring (in humans, a baby). In plants, it is the undeveloped plant contained within a seed.
Embryo sac A large cell that develops in the ovule of flowering plants (angiosperms). It contains the egg cell, the female gametophyte, where pollination occurs, and when fertilized it becomes an embryo and eventually a seed. It is formed from the growth and division of the megaspore into a multicellular structure with eight hap-loid nuclei.
Emigration The process of an individual or group leaving a population.
Emulsion Droplets of a liquid substance dispersed in another immiscible liquid. Milk in salad dressing is an emulsion.
Enantiomer one of a pair of molecular entities that are mirror images of each other and nonsuperimposable.
Endangered species The classification provided to an animal or plant in danger of extinction within the foreseeable future throughout all or a significant portion of its range.
Colored scanning electron micrograph (SEM) of a human embryo at the 16-cell stage, four days after fertilization. Known as a morula, this is a cluster of large rounded cells called blastomeres. The surface of each cell is covered in microvilli. The smaller spherical structures seen will degenerate. This embryo is at the early stage of transformation into a human composed of millions of cells. Here it is in the process of dividing to form a hollow ball of cells (the blastocyst). At this 16-cell stage, the morula has not yet implanted in the uterus (womb). Magnification: x620 at 6 x 7 cm size; x2,300 at 8 x 10 in. size; x 960 at 4 x 5 in. size.
The Karner Blue—New York’s Endangered Butterfly
The Karner blue (Lycaeides melissa samuelis) is a small, beautifully colored blue butterfly that died out in southern Canada in the early 1990s and was listed as an endangered species by the U.S. government in 1992.
The wings of male Karner blues are deep purplish-blue with a narrow black rim above, but females have wider dark gray borders around blue central areas on all four wings, and a row of bright orange spots on the upper hindwing edges. In both sexes, the wings have elegant white fringes, and are pale gray beneath with arcs of black, white-rimmed dots and orange and satiny blue spots along the hindwing margin. The wings expand about an inch, so the butterfly is quite small.
The Karner blue was first discovered in Canada near London, Ontario, by lepidopterist William Saunders in 1861, and in the United States at Center (now Karner), New York, by Joseph Albert Lintner in 1869. It was originally confused with Scudder’s blue (Lycaeides idas scudderi), a very similar and closely related but more northern butterfly. Vladimir Nabokov, the world-famous author best known for his controversial novel Lolita, also studied butterflies and described the Karner blue as new to science in 1943.
The Karner blue is restricted to a special kind of dry, sandy habitat where wild blue lupine (Lupinus perennis), its one caterpillar food plant, grows. Such areas of extensive sand, commonly called "sand plains," are of postglacial origin and occur along major rivers or around large lakes in northeastern and north-central North America.
The type locality, or the place from which the Karner blue was first scientifically described, is the Karner Pine Bush, a large inland pine barrens between Albany and Schenectady, New York. This habitat is unusual in being formed on undulating sand dunes that are stabilized by a low plant cover and widely scattered pitch pines (Pinus rigida). Resplendent clumps of wild blue lupine bloom in open areas between shrubby oaks (Quercus ilicifolia and Q. prinoides), blueberries (Vaccinium angustifolium and V. pallidum), prairie grasses (Schizachyrium scoparium), and other low herbaceous plants that carpet the dunes. Such landscapes are a type of savannah, maintained by a natural fire cycle that keeps them open. Their parklike vegetation is often very beautiful and quite different from the dense forests that surround the sand plains.
The Karner blue occurs very locally throughout its range, with small clusters of populations living many miles apart. The butterfly was historically known from sites in Maine, New Hampshire, Massachusetts, New York, New Jersey, Pennsylvania, Ohio, Indiana, Illinois, Wisconsin, Iowa, Minnesota, Michigan, and Ontario. Many locality records are very old, and the butterfly has since been extirpated in areas such as Brooklyn, in New York City, and the suburbs of Chicago. More recently, Karner blues have died out in New England and from New York City to Illinois along the southern edge of their range, except for northern Indiana. The butterfly is presently known to persist naturally only in Indiana, Michigan, Minnesota, Wisconsin, and the upper Hudson River Valley in New York, with reintroductions attempted in Ohio and planned for several other areas where it formerly lived.
The Karner blue’s annual life cycle proceeds like clockwork: the first hatch of Karner blue adults flies in late May and early June, when the lupines bloom. After mating, females lay tiny greenish-white, turban-shaped eggs on lupine plants at the same season. Within a week, minuscule caterpillars hatch from the eggs and begin to feed on lupine leaflets, leaving translucent holes as their unique feeding sign. They are often attended by ants, which feed on a sweet fluid the caterpillars produce in glands on their abdomens, incidentally reducing predation and parasitism. When fully grown three weeks later, the caterpillars are half an inch long, with black heads, velvety green bodies, a dark stripe along their backs, and light stripes along their sides. They crawl off the plant to find a sheltered place in the litter for their chrysalis, which is smooth, bright green, and held to the substrate by a white silken thread around the middle and by microscopic hooks embedded in a silk pad at the tail end. Over the next week the developing butterfly’s wings slowly change from green to white to orange and finally to purplish-blue inside the transparent chrysalis skin. The second brood of adults hatches from mid-July to early August, and after mating, females again lay eggs on or near the lupine plants, which by now have largely withered. These summer eggs do not hatch until the following April, when new lupine leaves are pushing through the sand. The tiny spring caterpillars grow, pupate, and produce a new brood of butterflies in late May, finishing the cycle of two full broods per year. These dates are for New York State. The timing of this annual calendar may shift a week or two later at the northern and western edges of the butterfly’s range, but the sequence remains the same.
Because this butterfly naturally occurred along or near waterways where major human settlements have grown, the Karner blue has been frequently subjected to urbanization stresses ever since Europeans colonized North America. Human disturbance and degradation of its habitat are primarily responsible for this butterfly’s endangered status throughout its range. A more subtle effect has been disruption of the natural fire cycles that keep its habitats open and sunny. Without fire, the barrens grow up into forests, shading out open areas the butterflies need for mating, feeding, and egg laying, and reducing the lupine plants that are necessary for its caterpillars to survive. Global warming may also be taking its toll: relatively mild winters in the Northeast since the early 1970s have reduced or eliminated the annual snowpack that shelters the overwintering eggs from December to March, forcing them to hatch too early, dessi-cate on sunbaked spring sand, or lie exposed to predators and parasitoids during this defenseless life stage.
Intensive scientific studies of the Karner blue have been conducted since 1973, when people first realized that it was declining in New York. Private conservation efforts began soon after, starting with the Pine Bush Historic Preservation Project, the Karner Blue Project (conducted by Robert Dirig and John F. Cryan), and the Xerces Society (led by Robert Michael Pyle and Jo Brewer). Spider Barbour of the rock group Chrysalis composed the song "Shepherd’s Purse" in the 1970s to highlight the butterfly’s plight. After the Karner blue was classified as threatened or endangered in various states, governmental funding became available, and many ecological studies were conducted by professional scientists. Today the Karn-er blue is extremely well known biologically (for example, we know the elemental composition of its eggshell), and the butterfly has also been the subject of several studies of preservation strategies. Habitat conservation efforts have continued at Karner (Albany Pine Bush), where approximately 2,750 acres of the type locality have been preserved to date. Managing this large preserve is challenging, as its location between urban centers discourages the fires that are needed to maintain the open vegetation Karner blues require. Additional preserves have been set aside for the butterfly and its habitat in many places throughout its range.
The Xerces Society was founded in 1971 to focus on insect conservation, and initially emphasized imperiled North American butterflies. This group’s scope has broadened over the past three decades to include all terrestrial and marine invertebrates, and has had an important, if subtle, impact on North American conservation efforts. It is named for the Xerces blue (Glaucopsychexerces), a California butterfly similar to the Karner blue that became extinct in the 1940s. This vanished insect lived on coastal sand dunes, where its caterpillars fed on a small legume in San Francisco, before its habitat was ruined. Other butterflies that the Xerces Society has championed include the Atala hairstreak (Eumaeus atala) and Schaus’ swallowtail (Papilio aristode-mus ponceanus) in southern Florida; and Smith’s blue (Euphilotes enoptes smithi), El Segundo blue (Euphilotes battoides allyni), mission blue (Icaricia icarioides missionen-sis), and the San Bruno elfin (Callophrys mossii bayensis) in California. This organization has also expended much effort in trying to help protect the migratory monarch’s (Danaus plexippus) spectacular overwintering sites in Mexico.
Among these, the Karner blue is an enduring example of ongoing human commitment to preserve an endangered insect in an increasingly crowded world.
Endangered Species Act of 1973 (amended) Federal legislation in the United States intended to provide a means whereby the ecosystems upon which endangered and threatened species depend may be conserved, and to provide programs for the conservation of those species in the hope of preventing extinction of native plants and animals.
Endemic species A species native and confined to a certain region; a species having comparatively restricted distribution.
Endergonic reaction A chemical reaction that consumes energy rather than releases energy. Endergonic reactions are not spontaneous because they do not release energy.
