How Camillo Golgi became “the Golgi”

On April 1898 Camillo Golgi communicated to the Medical-Surgical Society of Pavia, the discovery of the “internal reticular apparatus”, a novel intracellular organelle which he observed in nerve cells with the silver impregnation he had introduced for the staining of the nervous system. Soon after the discovery it became evident that this cellular component, which was also named the “Golgi apparatus”, was a ubiquitous structure in eukaryotic cells. However the reality of the organelle was questioned for years and many cytologists considered the internal reticular apparatus as an artefact due to the fixation and/or metallic impregnation procedure. The controversy was finally solved in the mid-1950s by electron microscopy when the Golgi apparatus definitely acquired its dignity of being a genuine cell organelle. The designation of “Golgi complex” entered officially in the literature in 1956. Both the terms Golgi apparatus and Golgi complex are currently interchangeable. However a quick “the Golgi” and the introduction of Golgi in adjectival form are now prevalent in the blooming scientific literature on the organelle. Thus Camillo Golgi underwent his final transformation and, becoming the eponym of the organelle he had discovered, he found a way to immortality.     

Adelchi Negri and Schools of General Pathology in Italy between the end of the nineteenth and beginning of the twentieth century

The long lasting scientific collaboration of Adelchi Negri with Camillo Golgi in the Laboratory of General Pathology and Histology of Pavia began in 1898–99, when he was still a medical student, and at about the time basic knowledge about human malaria transmission cycle (to which Golgi himself had given important contributions) was completed. On the occasion of the 100^th anniversary of the discovery of Negri bodies, this article provides a short overview of the scientific and cultural context in whichNeurocytes hydrophobiae hypothesis matured. To the same intent and purposes, this article also delineates some of the important scientific achievements in the field of General Pathology by Negri’s contemporaries, reflecting both the influence of the two great pioneers in the field (Bizzozero and Golgi), and the close contact with European science in the 1890’s to the end of the first World War, when biological science in Italy entered a new crisis.

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Adelchi Negri e le Scuole di Patologia generale nel passaggio dall’Ottocento al Novecento

Riassunto  La lunga collaborazione scientifica di Adelchi Negri con Camillo Golgi, nel Laboratorio di Patologia generale ed Istologia di Pavia, ebbe inizio nel 1898–99, quando questi era ancora studente di Medicina, e la conoscenza di base sul ciclo di trasmissione della malaria nell’uomo (alla quale lo stesso Golgi aveva dato importanti contributi in studi pionieristici) era completata. In occasione del Centenario della scoperta dei Corpi del Negri, questo articolo offre una rassegna sintetica del contesto scientifico-culturale in cui maturò l’ipotesi delNeurocytes hydrophobiae come agente causale della rabbia. Con questo intento e per lo stesso scopo, questo articolo traccia anche alcuni degli importanti raggiungimenti scientifici nel campo della Patologia generale da parte dei contemporanei di Negri, nei quali è rinvenibile, sia l’influenza dei grandi pionieri della disciplina (Bizzozero e Golgi), sia lo stretto contatto con la scienza europea, tra il 1890 circa e la fine della prima guerra mondiale, allorché la scienza biologica italiana entrò in una nuova crisi.

     

Poetry and Precision: Johannes Thienemann,the Bird Observatory in Rossitten and Civic Ornithology, 1900–1930

In the early twentieth century, ornithology underwent significant changes. So far, these changes, basically, have been studied by focussing on the elite of professional biologists working at universities or state museums. However, important developments also occurred in what Lynn Nyhart has called “the civic realm” of science – the sphere given form by private naturalist associations, nature writers, taxidermists and school teachers. This article studies the changing dynamics of civic ornithology, by looking at one particular case: the influential orinthological observatory in Rossitten, East-Prussia. This observatory, the first of its kind, was founded in 1901 and led, for the first three decades of its existence, by the minister Johannes Thienemann. This article analyses the ornithological practices Thienemann developed in Rossitten and the rhetoric he used to defend these practices. In both, so it is argued, one finds a mixture of the traditional, locally anchored naturalist approach with the new ideals of the “modern” and “experimental” university laboratories. The innovations which Thienemann introduced in this hybrid form of ornithology called for specific spatial strategies which made optimal use of the natural chatacteristics of his workplace and which mobilized a large civic network of geograhically scattered amateurs. At the same time, his work also altered the space he shared with the birds – materially, conceptually and culturally. Thus, this article maintains Thienemann's ornithology can only be understood by acknowledging its continuous interaction with the geographical and civic context in which it arose.     

Evolutionary Morphology in Belgium

In historical literature, Edouard van Beneden (1846–1910) is mostly remembered for his cytological discoveries. Less well known, however, is that he also introduced evolutionary morphology – and indeed evolutionary theory as such – in the Belgian academic world. The introduction of this research programme cannot be understood without taking both the international and the national context into account. It was clearly the German example of the Jena University that inspired van Beneden in his research interests. The actual launch of evolutionary morphology at his University of Liège was, however, also connected with the dynamic of Belgian university reforms and the local rationale of creating a research “school.” Thanks to his networks, his mastering of the rhetoric of the “new” biology, his low ideological profile and his capitalising on the new academic élan in late-19th century Belgium, van Beneden managed to turn his programme into a local success from the 1870s onwards. Two decades later, however, the conceptual underpinnings of evolutionary morphology came under attack and the “Van Beneden School” lost much of its vitality. Despite this, van Beneden’s evolutionary morphology was prototypical for the research that was to come. He was one of the first scientific heavyweights in Belgium to turn the university laboratory into a centre of scientific practice and the hub of a research school.     

Pierre Miquel: the first professional aerobiologist

Pierre Miquel (1850–1922) was one of the fathers of Aerobiology, which he called Atmospheric Micrography. After studying both Pharmacy and Medicine, he decided to investigate, under strict protocols, the living organisms of the atmosphere, brought to light by Pasteur some 20 years earlier. All his aerobiological work was done at Paris Montsouris Observatory where he was ‘chief micrographer’ for 34 years. He was an active promoter of using only volumetric methods, and an early believer in ‘micrography statistics’. His most important works dealing with aerobiology were related to weather influences on atmospheric bioaerosols and on their impacts on epidemic diseases.     

Last judgment: the visionary biology of J.B.S. Haldane

This paper seeks to reinterpret the life and work of J. B. S. Haldane by focusing on an illuminating but largely ignored essay he published in1927, “The Last Judgment” – the sequel to his better known work, Daedalus (1924). This astonishing essay expresses a vision of the human future over the next 40,000,000 years, one that revises and updates Wellsian futurism with the long range implications of the “new biology” for human destiny. That vision served as a kind of lifelong credo, one that infused and informed his diverse scientific work, political activities, and popular writing, and that gave unity and coherence to his remarkable career. This revised version was published online in July 2006 with corrections to the Cover Date.     

Darwin on Aristotle

Charles Darwin's famous 1882 letter, in response to a gift by his friend, William Ogle of Ogle's recent translation of Aristotle's Parts of Animals, in which Darwin remarks that his “two gods,” Linnaeus and Cuvier, were “mere school-boys to old Aristotle,” has been thought to be only an extravagantly worded gesture of politeness. However, a close examination of this and other Darwin letters, and of references to Aristotle in Darwin's earlier work, shows that the famous letter was written several weeks after a first, polite letter of thanks, and was carefully formulated and literally meant. Indeed, it reflected an authentic, and substantial, increase in Darwin's already high respect for Aristotle, as a result of a careful reading both of Ogle's Introduction and of more or less the portion of Ogle's translation which Darwin says he has read. Aristotle's promotion to the pantheon, as an examination of the basis for Darwin's admiration of Linnaeus and Cuvier suggests, was most likely the result specifically of Darwin's late discovery that the man he already knew as “one of the greatest ... observers that ever lived” (1879) was also the ancient equivalent both of the great modern systematist and of the great modern advocate of comparative functional explanation. It may also have reflected some real insight on Darwin's part into the teleological aspect of Aristotle's thought, indeed more insight than Ogle himself had achieved, as a portion of their correspondence reveals. This revised version was published online in July 2006 with corrections to the Cover Date.     

From sepiamelanin to chemical ecology of opisthobranchs and diatoms: an exciting 40 years game in the field of marine natural products

This paper reports the lecture delivered on the occasion of the “Ceremony of Professional Recognition” to the author at the 6th European Conference on Marine Natural Products (Porto, Portugal, 19–23 July 2009). The most recent results obtained studying opisthobranchs and diatoms at ICB are presented after a synthetic overview of the most significant moves played during this exciting 40 years game in the field of Marine Natural Products. In a symbolic manner this career is compared to a chess game. After the “romantic” opening dedicated to the study of natural black (melanin) and red-brown (phaeomelanins) pigments in the prestigious group of Rodolfo A. Nicolaus, the research on marine organisms started in 1969 and rapidly led to the characterization of an impressive number of new compounds exhibiting very unusual structures. Substantially, the “structure hunt” ended with the publication of a series of alkaloids with absolutely unprecedented structural features: the saraines. Slowly, the scientific interest shifted “from structure to function”. Opisthobranchs were selected as models to investigate. The majority of the protective allomones possessed by opisthobranch molluscs are sequestered through the food chain from algae and invertebrates. However, opisthobranchs were also able to biosynthesize many compounds structurally related to typical molecules possessed by their prey. These aspects “from function to ecology, to biosynthesis, to evolution” are discussed in detail.     

B P Belousov and his reaction

The generation to which Boris Pavlovich Belousov (1893–1976) belonged has almost disappeared. The archives hold only a few documents about his life and basically secret research. This article is a brief biography of Belousov and attempts to reconstruct what lay behind his famous discovery of the oscillatory homogeneous chemical reaction named after him.     

Tantalizing Tortoises and the Darwin-Galápagos Legend

During his historic Galápagos visit in 1835, Darwin spent nine days making scientific observations and collecting specimens on Santiago (James Island). In the course of this visit, Darwin ascended twice to the Santiago highlands. There, near springs located close to the island’s summit, he conducted his most detailed observations of Galápagos tortoises. The precise location of these springs, which has not previously been established, is here identified using Darwin’s own writings, satellite maps, and GPS technology. Photographic evidence from excursions to the areas where Darwin climbed, including repeat photography over a period of four decades, offers striking evidence of the deleterious impact of feral mammals introduced after Darwin’s visit. Exploring the impact that Darwin’s Santiago visit had on his thinking – especially focusing on his activities in the highlands – raises intriguing questions about the depth of his understanding of the evolutionary evidence he encountered while in the Galápagos. These questions and related insights provide further evidence concerning the timing of Darwin’s conversion to the theory of evolution, which, despite recent claims to the contrary, occurred only after his return to England.     

Not Beyond Reasonable Doubt: Howard Temin’s Provirus Hypothesis Revisited

During the 1960s, Howard M. Temin (1934–1994), dared to advocate a “heretical” hypothesis that appeared to be at variance with the central dogma of molecular biology, understood by many to imply that information transfer in nature occurred only from DNA to RNA. Temin’s provirus hypothesis offered a simple explanation of both virus replication and viral-induced cancer and stated that Rous sarcoma virus, an RNA virus, is replicated via a DNA intermediate. Popular accounts of this scientific episode, written after the discovery of an RNA-directed DNA polymerase in 1970, tend to describe the reaction to his proposition as ardent opposition. Typically these accounts use a ‹molecular biology’ standpoint emphasizing the central dogma’s part in its rejection. In this article, however, this episode will be examined from a joint perspective of virology and experimental cancer research. From this perspective it is clear that Temin’s work was well within the epistemological and methodological boundaries of virology and cancer research. Still, scientists did have␣reasons to doubt the provirus hypothesis, but these do not seem to be good enough to either justify an account that portrays Temin as a renegade or his ideas as heretical.     

R. J. Gordon’s Discovery of the Spotted Hyena’s Extraordinary Genitalia in 1777

In the history of zoology the English anatomist Morrison Watson (1845–1885) is considered to be the discoverer of the masculinized sexual organs of the spotted hyena. Beginning in 1877, Watson had published a series of anatomical studies on the spotted hyena (Watson, 1877, 1878, 1881, Watson and Young, 1879), in which he, in which he for the first time made public the anatomical peculiarities of the female spotted hyena’s genitalia. This scientific achievement is well documented. But now we can also state that a hundred years before Watson the Dutch amateur zoologist Robert Jacob Gordon (1743–1795), while serving in the Scots Brigades at the Cape of Good Hope, had already made the same discovery and merely unfortunate personal circumstances prevented publication. During his stay at the Cape, Gordon had studied spotted hyenas intensively and recorded his observations in accurate drawings and comments. These drawings have been preserved as part of a large collection of animal drawings entitled Gordon Atlas. With his discovery, Gordon actually was the first to provide empirical evidence of a “curious and inexplicable case of dimorphism” (Darwin on a beetle) in mammalians, long before étienne Geoffrey Saint-Hilaire (Cours de l’histoire naturelle des mammifères, 1829) started examining masculinized sexual organs in the mole or Darwin recognized the importance of sexual dimorphism (Descent of Man, 1871). In this paper we reproduce for the first time all hyena drawings from the Gordon Atlas, including Gordon’s handwritten notes in the margins in the original Dutch and in translation. Additionally, we briefly delineate the knowledge about the South African spotted hyena in Gordon’s time and indicate that we doubt Watson’s explanation for the age-old confusion about the hyena.     

Are Animals Just Noisy Machines?: Louis Boutan and the Co-invention of Animal and Child Psychology in the French Third Republic

Historians of science have only just begun to sample the wealth of different approaches to the study of animal behavior undertaken in the twentieth century. To date, more attention has been given to Lorenzian ethology and American behaviorism than to other work and traditions, but different approaches are equally worthy of the historian’s attention, reflecting not only the broader range of questions that could be asked about animal behavior and the “animal mind” but also the different contexts in which these questions were important. One such approach is that represented by the work of the French zoologist Louis Boutan (1859–1934). This paper explores the intellectual and cultural history of Boutan’s work on animal language and the animal mind, and contextualizes the place of animal behavior studies within late-nineteenth-and early-twentieth-century French biology. I explore the ways in which Boutan addressed the philosophical issue of whether language was necessary for abstract thought and show how he shifted from the idea that animals were endowed with a purely affective language to the notion that of they were capable of “rudimentary” reasoning. I argue that the scientific and broader socio-cultural contexts in which Boutan operated played a role in this transition. Then I show how Boutan’s linguistic and psychological experiments with a gibbon and children provide insights into his conception of “naturalness.” Although Boutan reared his gibbon at home and studied it in the controlled environment of his laboratory, he continued to identify its behavior as “natural.” I specifically demonstrate the importance of the milieu of the French Third Republic in shaping Boutan’s understanding not only of animal intelligence and child education, but also his definition of nature. Finally, I argue that Boutan’s studies on the primate mind provide us with a lens through which we can examine the co-invention of animal and child psychology in early-twentieth-century France.     

Allosteric regulation of the Golgi inosine diphosphatase from corn roots

Summary Light microsomes of corn roots, enriched in endoplasmic reticulum and Golgi membranes, have an IDPase activity which is stimulated by Triton X-100 and by cold storage. In the native state, the enzyme activity does not follow Michaelis-Menten kinetics. It hydrolyses IDP with K_0.5 of about 900 μM and V_max of 300–400 nmol P_i/mg protein/min. In the presence of Triton X-100, the enzyme is maximally stimulated and it renders to a Michaelis-Menten behavior with a K_m of about 500 μM and a V_max of 800–1200 nmol P_i/mg protein/min. The maximal effect of the detergent occurs at about 1 mM IDP (270%), being reduced (190%) at high IDP concentrations (>2 mM) which, per se, have a slight stimulatory effect on the enzyme. On the other hand, we observed that ATP (>2 mM) and adenosine inhibit the IDPase. The effects of the nucleotides and of the adenosine are abolished in the presence of Triton X-100, which makes the enzyme fully active. Furthermore, we observed that detergent treatment of the membranes reduces the change in the activation energy which occurs at 10 °C and eliminates cooperative effects, as revealed by the Arrhenius analysis and the Hill analysis, respectively. We also observed that IDPase inhibition by ATP is maximal at low IDP concentrations (1 mM), whereas it decreases at high concentrations of IDP (4 mM), which promote maximal velocities in the native enzyme. Conversely, the inhibitory effect of adenosine is not reduced at high IDP concentrations. Pyrophosphate also inhibits the IDPase, but the effect is non-competitive and it is cumulative with that of ATP. We also observed that the latent activity of the IDPase (Triton-stimulated IDPase) is reduced by pre-treatment of the membranes with glutaraldehyde. The results indicate that Golgi IDPase is an allosteric enzyme which is positively modulated by IDP and negatively modulated by ATP and adenosine. Pyrophosphate inhibits the IDPase, but it seems to act at the catalytic site, whereas the other modulators appear to interact with a distinct regulatory site.     

Panpsychic Organicism: Sewall Wright’s Philosophy for Understanding Complex Genetic Systems

Sewall Wright first encountered the complex systems characteristic of gene combinations while a graduate student at Harvard’s Bussey Institute from 1912 to 1915. In Mendelian breeding experiments, Wright observed a hierarchical dependence of the organism’s phenotype on dynamic networks of genetic interaction and organization. An animal’s physical traits, and thus its autonomy from surrounding environmental constraints, depended greatly on how genes behaved in certain combinations. Wright recognized that while genes are the material determinants of the animal phenotype, operating with great regularity, the special nature of genetic systems contributes to the animal phenotype a degree of spontaneity and novelty, creating unpredictable trait variations by virtue of gene interactions. As a result of his experimentation, as well as his keen interest in the philosophical literature of his day, Wright was inspired to see genetic systems as conscious, living organisms in their own right. Moreover, he decided that since genetic systems maintain ordered stability and cause unpredictable novelty in their organic wholes (the animal phenotype), it would be necessary for biologists to integrate techniques for studying causally ordered phenomena (experimental method) and chance phenomena (correlation method). From 1914 to 1921 Wright developed his “method of path coefficient” (or “path analysis”), a new procedure drawing from both laboratory experimentation and statistical correlation in order to analyze the relative influence of specific genetic interactions on phenotype variation. In this paper I aim to show how Wright’s philosophy for understanding complex genetic systems (panpsychic organicism) logically motivated his 1914–1921 design of path analysis.     

Nicolas Rashevsky's Mathematical Biophysics

This paper explores the work of Nicolas Rashevsky, a Russian émigré theoretical physicist who developed a program in “mathematical biophysics” at the University of Chicago during the 1930s. Stressing the complexity of many biological phenomena, Rashevsky argued that the methods of theoretical physics – namely mathematics – were needed to “simplify” complex biological processes such as cell division and nerve conduction. A maverick of sorts, Rashevsky was a conspicuous figure in the biological community during the 1930s and early 1940s: he participated in several Cold Spring Harbor symposia and received several years of funding from the Rockefeller Foundation. However, in contrast to many other physicists who moved into biology, Rashevsky's work was almost entirely theoretical, and he eventually faced resistance to his mathematical methods. Through an examination of the conceptual, institutional, and scientific context of Rashevsky's work, this paper seeks to understand some of the reasons behind this resistance. This revised version was published online in July 2006 with corrections to the Cover Date.     

Tubules of the trans Golgi apparatus visualized by immunoelectron microscopy

 Tubules constitute an integral part of the Golgi apparatus and have been shown to form a complex and dynamic network at its trans side. We have studied in detail structural features of the trans Golgi network and its relationship with the cisternal stack in thin sections of Lowicryl K4M embedded human absorptive enterocytes by immunolectron microscopy. Immunoreactive sites for α1,3 N-acetylgalactosaminyltransferase and blood group A substance were detectable troughout the cisternal stack and the entire trans Golgi network. Furthermore, the entire trans Golgi network was reactive for CMPase activity. Evidence for two kinds of tubules at the trans side of the Golgi apparatus was found: tubules that laterally connect adjacent and distant cisternal stacks, and others extending from central and lateral portions of trans cisternae to form the complex and extensive trans Golgi network. Trans cisternae showed often the peeling-off phenomenon and were continuous with the trans Golgi network. Both, trans cisternae and tubules of the trans Golgi network exhibited regionally buds and vesicles with a lace-like, non clathrin coat, previously reported by others in NRK cells, which contained glycoproteins with terminal N-acetylgalactosamine residues. These buds and vesicle are therefore involved in constitutive exocytosis. Accepted: 12 January 1998     

Anion channels transport ATP into the Golgi lumen

Anion channels provide a pathway for Cl^– influx into the lumen of the Golgi cisternae. This influx permits luminal acidification by the organelle's H⁺-ATPase. Three different experimental approaches, electrophysiological, biochemical, and proteomic, demonstrated that two Golgi anion channels, GOLAC-1 and GOLAC-2, also mediate ATP anion transport into the Golgi lumen. First, GOLAC-1 and -2 were incorporated into planar lipid bilayers, and single-channel recordings were obtained. Low ionic activities of K₂ATP added to the cis-chamber directly inhibited the Cl^– subconductance levels of both channels, with K_m values ranging from 16 to 115 µM. Substitution of either K₂ATP or MgATP for Cl^– on the cis, trans, or both sides indicated that ATP is conducted by the channels with a relative permeability sequence of Cl^– > ATP^4– > MgATP^2–. Single-channel currents were observed at physiological concentrations of Cl^– and ATP, providing evidence for their importance in vivo. Second, transport of [-³²P]ATP into sealed Golgi vesicles that maintain in situ orientation was consistent with movement through the GOLACs because it exhibited little temperature dependence and was saturated with an apparent K_m = 25 µM. Finally, after transport of [-³²P]ATP, a protease-protection assay demonstrated that proteins are phosphorylated within the Golgi lumen, and after SDS-PAGE, the proteins in the phosphorylated bands were identified by mass spectrometry. GOLAC conductances, [-³²P]ATP transport, and protein phosphorylation have identical pharmacological profiles. We conclude that the GOLACs play dual roles in the Golgi complex, providing pathways for Cl^– and ATP influx into the Golgi lumen. Golgi complex; Cl channel; mass spectrometry; phosphorylation     

The Preface to Darwin’s <Emphasis Type="Italic">Origin of Species</Emphasis>: The Curious History of the “Historical Sketch” *

Almost any modern reader’s first encounter with Darwin’s writing is likely to be the “Historical Sketch,” inserted by Darwin as a preface to an early edition of the Origin of Species, and having since then appeared as the preface to every edition after the second English edition. The Sketch was intended by him to serve as a short “history of opinion” on the species question before he presented his own theory in the Origin proper. But the provenance of the “Historical Sketch” is somewhat obscure. Some things are known about its production, such as when it first appeared and what changes were made to it between its first appearance in 1860 and its final form, for the fourth English edition, in 1866. But how it evolved in Darwin’s mind, why he wrote it at all, and what he thought he was accomplishing by prefacing it to the Origin remain questions that have not been carefully addressed in the scholarly literature on Darwin. I attempt to show that Darwin’s various statements about the “Historical Sketch,” made primarily to several of his correspondents between 1856 and 1860, are somewhat in conflict with one another, thus making problematic a satisfactory interpretation of how, when, and why the Sketch came to be. I also suggest some probable resolutions to the several difficulties. How Darwin came to settle on the title “Historical Sketch” for the Preface to the Origin is not certain, but a guess may be ventured. When he first submitted the text to Asa Gray in February 1860 he called it simply “Preface Contributed by the Author to this American Edition” (Burkhardt et al., eds., vol. 8, 1993, p. 572; the collected correspondence is hereafter cited as CCD). In fact he had thought of it as being properly called a Preface much earlier, perhaps as early as 1856, as will be seen in what follows. It came to be called “An Historical Sketch of the Recent Progress of Opinion on the Origin of Species” only in the third English edition, April 1861. This is the title it retained thereafter, with the exception of an addition to the title in the sixth English edition, “Previously to the Publication of the First Edition of this Work” (Peckham, 1959, pp. 20, 59). The word “sketch,” on the other hand was one of two words Darwin commonly used in private correspondence to refer to the book that would later become the Origin, the other word being “Abstract,” and both signifying that Darwin thought of the work as being a resume rather than a full-fledged study (e.g., letter to J.D. Hooker, May 9 1856, CCD vol. 6 p. 106; letter to Baden Powell January 18 1860, CCD vol. 8 p. 41; letter to Lyell 25 June 1858, CCD v. 7, 1991, pp. 117–8; letter to Lyell May 1856, CCD, v. 6 p. 100). The most likely source of the title “Historical Sketch” for Darwin’s Preface is Charles Lyell’s Principles of Geology in which, beginning with the third edition (1834), Lyell added titles to his chapters, calling chapters 2–4 “Historical Sketch of the Progress of Geology” (Secord, in Lyell [1997], p. xlvii; for other uses by Lyell of this expression, cf. Porter, 1976, p. 95; idem 1982, p. 38; and Lyell, 1830 [1990], p. 30). Further parallels between Lyell’s Introduction and Darwin’s “Historical Sketch” in terms of content and strategy are suggested below.     

Reconstitution of the Golgi apparatus after microinjection of rat liver Golgi fragments into Xenopus oocytes

We have studied the reconstitution of the Golgi apparatus in vivo using an heterologous membrane transplant system. Endogenous glycopeptides of rat hepatic Golgi fragments were radiolabeled in vitro with [3H]sialic acid using detergent-free conditions. The Golgi fragments consisting of dispersed vesicles and tubules with intraluminal lipoprotein-like particles were then microinjected into Xenopus oocytes and their fate studied by light (LM) and electron microscope (EM) radioautography. 3 h after microinjection, radiolabel was observed by LM radioautography over yolk platelet-free cytoplasmic regions near the injection site. EM radioautography revealed label over Golgi stacked saccules containing the hepatic marker of intraluminal lipoprotein-like particles. At 14 h after injection, LM radioautographs revealed label in the superficial cortex of the oocytes between the yolk platelets and at the oocyte surface. EM radioautography identified the labeled structures as the stacked saccules of the Golgi apparatus, the oocyte cortical granules, and the plasmalemma, indicating that a proportion of microinjected material was transferred to the surface via the secretion pathway of the oocyte. The efficiency of transport was low, however, as biochemical studies failed to show extensive secretion of radiolabel into the extracellular medium by 14 h with approximately half the microinjected radiolabeled constituents degraded. Vinblastine (50 microM) administered to oocytes led to the formation of tubulin paracrystals. Although microinjected Golgi fragments were able to effect the formation of stacked saccules in vinblastine-treated oocytes, negligible transfer of heterologous material to the oocyte surface could be detected by radioautography. The data demonstrate that dispersed fragments of the rat liver Golgi complex (i.e., unstacked vesicles and tubules) reconstitute into stacked saccules when microinjected into Xenopus cytoplasm. After the formation of stacked saccules, reconstituted Golgi fragments transport constituents into a portion of the exocytic pathway of the host cell by a microtubule-regulated process.