Dickson D Despommier

• PhD
• Professor Emeritus at Columbia University

Urban agriculture is here to stay. Rooftop greenhouses, outdoor gardens, and vertical farms now dot the built environment landscape. This chapter details the advances made in indoor agriculture and documents the establishment of vertical farms (multi-storey greenhouses). Technologies for growing crops indoors are reviewed and many commercial vertic...

Jens Kuhn returns to TWiV to explain Select Agents, Priority Pathogens, Australia List Pathogens, Risk Group Agents, biosafety, biosecurity, and biosurety.

Jens returns to present a brief history of bioweapons, with a focus on the program in the Soviet Union, the largest ever undertaken, and his experience working in the decommissioned Soviet bioweapons laboratory known as Vector.

This is an established medical textbook dealing with basic and clinical aspects of infectious diseases caused by eukaryotic pathogens. It is now in its 6th edition.

http://www.twiv.tv/2015/10/04/twiv-357/ Jens joins the TWiVomics to discuss the strengths and weaknesses of viral taxonomy, including its history and evolution, how viruses are ordered, and why T. rex was classified without having a living isolate.

The history of how we became an agrarian society and of farming’s increasingly destructive force on the world’s functional ecosystems provides convincing proof that soil-based farming is not working and probably never did. Over 12,000 years of continuous human activity of working the land is a long time to prove or disprove something, but such has...

Over the next 50years, rapid climate change issues will play a major role in agriculture. It is estimated for every 1° of increase in atmospheric temperature, 10% of the land where we now grow food crops will be lost. The ability of governments to provide essential services for its citizens, and in particular to maintain systems that provide a reli...

The human population has reached some 6.4 billion individuals. Over 800 million hectares (i.e., nearly 38% of the total landmass of the earth) is committed to producing crops to support this still growing population. Farming has dramatically transformed the landscape, replacing and redefining functional ecosystems. Undeniably, a reliable food suppl...

Recognition of the significance of the boundary between ecological systems, often referred to as the ecotone, has a long history in the ecological sciences and in zoonotic disease research. More recent research in landscape ecology has produced an expanded view of ecotones and elaboration of their characteristics and functions in ecosystems. Parall...

Emerging Zoonoses and Pathogens of Public Health Concern. World Organization for Animal Health. Volume 23 (2), 2004. pp. 310. ISBN 92 9044 621 8. € 50 (airmail postage is included for all countries). - - Volume 131 Issue 1 - DICKSON DESPOMMIER

Toxocariasis is caused by a series of related nematode species (ascarids) that routinely infect dogs and cats throughout the world. The eggs from these ascarids are common environmental contaminants of human habitation, due largely to the fact that many kinds of dogs and cats serve as pets, while countless others run wild throughout the streets of...

The nurse cell-parasite complex of Trichinella spiralis is unlike anything else in Nature. It is derived from a normal portion of striated skeletal muscle cell and develops in a matter of 15 to 20 days after the larva invades that cell type. What are the molecular mechanisms at work that result in this unique relationship? Here, Dickson Despommier...

The L1 larval stage of Trichinella spiralis induces modification in a portion of striated skeletal muscle cell resulting in the formation of the nurse cell. This specialized host cell is completely encased in a capsule composed mainly of collagen type IV and type VI, which, in turn, is surrounded by a unique rete of vessels whose formation begins o...

The portion of skeletal muscle fiber (Nurse cell) harboring Trichinella spiralis is surrounded by an acellular capsule susceptible to digestion with collagenase. Antibodies recognized type IV and type VI collagen in the capsule, while the periodic acid Schiff reagent stained the capsule differentially, revealing at least two distinct layers. RNA an...

Trichinella spiralis is an intracellular parasitic nematode that infects skeletal muscle cells. Infection results in loss of tissue specific characteristics and conversion of the muscle cell to a Nurse cell. The characteristic changes leading to the formation of the Nurse cell appear complete by day 12 after intramuscular infection. Proteins synthe...

A 43-kDa secreted glycoprotein from the intracellular parasitic nematode Trichinella spiralis has been considered as a factor involved in the formation of the Nurse cell in infected muscle. The closely related intracellular parasitic nematode Trichinella pseudospiralis that also infects muscle cells, does not form Nurse cells and was thought not to...

Isolated cases and outbreaks of infection with Trichinella spp. occur frequently throughout the world, sometimes resulting in fatalities. The clinical presentations of signs and symptoms are remarkably constant for most of the species of Trichinella, but in infections with Trichinella nativa and Trichinella britovi, classical symptoms of trichinell...

Isolated cases and outbreaks of infection with Trichinella spp. occur frequently throughout the world, sometimes resulting in fatalities. The clinical presentations of signs and symptoms are remarkably constant for most of the species of Trichinella, but in infections with Trichinella nativa and Trichinella britovi, classical symptoms of trichinell...

Invasion of vertebrate muscle cells by larvae of Trichinella spiralis is accompanied by redifferentiation of the host myofiber into a novel structure called the nurse cell. The nurse cell protects and nurtures the enclosed parasite during its long stay in host muscle. It is anatomically independent of the surrounding uninfected muscle cells and can...

Balantidium coli is widely distributed throughout the word, but the prevalence of human infection is not known. Endemic foci have been reported from New Guinea, Micronesia, Seychelles Islands, and Central and South America.1Sporadic epidemics have occurred in institutionalized populations. Infected individuals harbor the parasite in the colon, the...

Infection by Trichinella spiralis induces host muscle cells to become repositioned within the cell cycle and to lose differentiated skeletal muscle characteristics. Antibodies to a 43-kDa excretory-secretory (ES) protein (p43) also bind to infected host cell nuclei. Neither the identity of these nuclear antigens nor their role in inducing the infec...

Trichinella spiralis is an intracellular parasite as both a larva and an adult. The first-stage larva lives in a modified portion of a skeletal muscle cell, the nurse cell, and can reside there for the life span of the host. Adult worms occupy a nonmembrane-bound portion of columnar epithelium, living there as intramulticellular parasites. The newb...

Trichinella spiralis is an intracellular parasite as both a larva and an adult. The first-stage larva lives in a modified portion of a skeletal muscle cell, the nurse cell, and can reside there for the life span of the host. Adult worms occupy a nonmembrane-bound portion of columnar epithelium, living there as intramulticellular parasites. The newb...

This article has no abstract; the first 100 words appear below. A diagnosis of neurocysticercosis, commonly caused by the larva of the pork tapeworm, Taenia solium, is rare enough to qualify for presentation at grand rounds in most medical centers throughout the United States. However, in Latin America and South Africa,¹ it is a frequent cause of c...

The L1 larvae of the parasitic nematode Trichinella spiralis invade skeletal muscle and initiate a process that has been interpreted to represent skeletal muscle dedifferentiation. In this process, the infected region of the muscle cell is converted into a unique structure, called the Nurse cell. The nematode T. spiralis can survive for tens of yea...

The rate of enlargement of nuclei was determined on 4-microns-thick sections of synchronously infected mouse thigh muscle. Normal muscle nuclei had a geometric mean volume of 84 microns and a range of 42-170 microns 3. At days 5, 6, 7, 8, and 10 and 6 mo after infection, mean nuclear volume was 177 (100-315) microns 3, 254 (140-462) microns 3, 278...

Larvae of Trichinella spiralis initiate the transformation of myocytes into nurse cells that become surrounded by elaborate networks of blood vessels. To examine the structure of these networks (i.e., retes), transcardic perfusion was used to clear the vascular tree of Trichinella-infected mice and to inject a plastic that polymerized in situ. Vasc...

Antibodies were elicited against a purified antigen with an apparent molecular weight of 43K. This antibody preparation also detected a second antigen consisting of a group of closely related components of 45-50K. These antigens are stage specific for the infective first stage larva of Trichinella spiralis and are among the repertoire of secreted a...

Two protein antigens were isolated from excretory-secretory products of Trichinella spiralis by biochemical methods and characterized with respect to their chemical and immunological properties. One antigen, of apparent Mr 43,000, is an abundant secreted protein of infective L1 larvae, while the other, of 45-50 kDa, is present in smaller amounts. Y...

Trichinella spiralis is one of the world's largest intracellular parasites. Unlike most such organisms, it does not kill the host cell, but induces modifications in cell structure that enhance its own survival. In this article, Dickson Despommier describes the ways in which the parasite uses the cell for its own benefit, and discusses the extent to...

The class Trematoda is divided into two orders, Monogenea and Digenea, both of which consist of obligate parasites. All of the trematodes of medical importance are classified within the order Digenea, and include the blood flukes, the intestinal flukes, and the tissue flukes. They are mainly found throughout the tropics and subtropics and only rare...

Four layers are present on the surface of infective larvae of Trichinella spiralis isolated from host muscle in pepsin-HCl. Trypsin treatment of pepsin-HCl isolated worms caused partial degradation and removal of large patches of the two outer surface layers. Following exposure to bile, only traces of the outer layers remained on the worms surface....

Monoclonal antibodies (mAb) recognizing epitopes on the 48K (beta stichocyte specific) and the 50/55K antigen (alpha stichocyte specific) were used as first ligands for immunocytolocalization on de-paraffinized sections of infected gut tissue of non-immune and immune CFW strain mice. The enteral phase was studied at 6, 14, 23, 30 hr and 7 days afte...

In both primary and secondary infections using 3 different strains of mice (DBA/1, B10 X D2, and C3H/HeJ), 2 peaks of peripheral blood eosinophilia were noted. Depending upon the strain, the first of the biphasic peaks in primary infections occurred between days 5 and 9, and the second peak occurred between days 16 and 22. The relative heights of t...

A 40-year-old man had regular cyclic episodes of weight gain and eosinophilic myositis associated with hyperimmunoglobulin-E and hypereosinophilia for 9 years. During the episodes his body weight increased up to 10.8%; eosinophil counts reached 41.3 X 10(-9) cells/L; and IgE levels reached 18 000 IU/mL. These values changed regularly in a definite...

Purification of two antigens (48-kilodalton polypeptide and a group with major subunits of 50 and 55 kilodaltons) from the infective larvae of the parasitic nematode Trichinella spiralis was recently reported. Immunization of mice with either of these antigens induces strong resistance to a subsequent challenge infection. In the study reported here...

Swine were immunized with partially purified stichosome antigens derived from Trichinella spiralis muscle larvae. In 3 trials, 500 to 600 micrograms of the solubilized particle component (S3) induced moderate levels of resistance to challenge inoculation; the percent reduction in larvae per gram of muscle ranged from 43 to 55. The effect of immuniz...

Intestinal infection by the coccidian parasite Cryptosporidium is a well-recognized condition in immunocompromised hosts and in some normal persons. The authors studied a patient with acquired immunodeficiency syndrome and cryptosporidiosis of the small intestine. The parasite inhabits the microvillous brush border of the intestinal epithelium and...

A series of monoclonal antibodies was generated for the purpose of studying antigens of the infective L1 larva of Trichinella spiralis. Primary immunization of donor BALB/c mice was by oral infection with L1 larvae. Secondary immunization and screening procedures for hybridoma clones employed a pool of affinity-purified antigens recognized by poole...

Various preparations of crude and a purified preparation of Trichinella spiralis antigens were compared in a rapid, micro-enzyme immunoassay (EIA) for detecting trichinellosis in swine. The crude antigen preparations (XM-300 or S3 fraction) were lipid-free, cell-free fractions of muscle larvae, and the purified antigen was prepared by immunoaffinit...

Most of the broad aspects of the life cycle of Trichinella were uncovered during the 50 years following its discovery and description by Paget and Owen in 1835 and are highlighted in Chapter 1, which deals with the history of this nematode. Nevertheless, many details of its enterai and parenteral life were not described until after 1960, and many h...

A large-particle fraction, derived from muscle larvae of Trichinella spiralis by a combination of homogenization and differential centrifugation, was treated with 0.1% Triton X-100 and then centrifuged at high speed in order to obtain the soluble portion of this fraction (i.e., S3 fraction). The S3 fraction was then subjected to immuno-affinity chr...

Proteins and antigens derived from a large-particle fraction of muscle larvae of Trichinella spiralis (i.e., the S3 fraction) were characterized in terms of their molecular weights, isoelectric points, carbohydrate contents, electrophoretic mobilities, antigenicity, and their ability to induce protection in mice. Gel filtration on Sephacryl S-200 y...

The soluble portion of a large particle fraction which was derived from the muscle larva of T. spiralis was subjected to molecular sizing column chromatography using Sephacryl S-200. Five major peaks of 280 nm absorbing material were obtained. Analysis by immunoelectrophoresis revealed that each peak contained antigens, with the majority of them oc...

Work has continued on the development and automation of enzyme immunoassays (EIA) for detecting diseases and toxic agents in food animals. Further evaluations were made of the Technicon Autoanalyzer II(AAII) for conducting totally automated EIAs. The problems investigated were machine carryover and assay variation. Modifications greatly reduced or...

Rats infected orally with Trichinella spiralis developed an immunity that was induced by and expressed against separate phases of the parasite's enteral life cycle. Infectious muscle larvae generated an immune response (rapid expulsion) that was directed against the very early intestinal infection and resulted in the expulsion of worms within 24 hr...

Mice, belonging to two strains, were infected by the oral route with muscle larvae of Trichinella spiralis. Host animals were killed at various times up to 48 hr after administration of larvae, and the infected small intestines were fixed immediately in 10% neutral formalin. Sections of infected gut, embedded in paraffin and cut at 5 μm, or in meth...

An improved assay technique is presented for the detection of matrone, the mosquito pheromone which prevents insemination in female mosquitoes. This new technique requires 24 hours less to complete. The number of repeat tests necessary is reduced by 50% as compared to the number required utilizing the old technique and the reliability of the test i...

Rats can be solidly immunized against Trichinella spiralis by a series of methyridine-terminated oral infections with T. spiralis larvae. Injections of thoracic duct lymphocytes (TDL) obtained from such animals can protect normal rats against a Trichinella challenge. The protective cells belong to two populations which differ with respect to their...

Thoracic duct lymphocytes or purified T or B cells obtained from specifically immunized (Lewis x DA)F1 hybrid rats can protect normal recipients against an oral challenge infection with T. spiralis. The immune cells increase the rate of expulsion of adult worms from the small intestine. Immune TDL do not affect adult worm fecundity, as they do in o...

Single infections of Trichinella spiralis of 48 h duration did not produce a significant degree of immunity in mice. Single or triple light infections of 7 h duration which, it is suggested, were composed entirely of fourth-stage larvae, did not produce significant immunity. Single infections of 3 or 4 days duration did produce immunity. It is sugg...

Trichinella spiralis is an unusual nematode parasite in two respects. First, it spends its larval and adult life in the same host, and second, it is rather non-specific in its mammalian host range. Because of the above facts, and since T. spiralis is also a human pathogen, many investigations into the immunology of the infection have been conducted...

Wistar-Furth strain male rats and CFW strain male mice were immunized against Trichinella spiralis using an antegenic fraction derived from a cell-free homogenate of mature muscle larvae. In rats, animlas immunized with 250 μg of antigen harboured singnificantly fewer (135000) muscle larvae 30 days after oral challenge than controls (231000). Furht...

The stichosome of the mature muscle larva of Trichinella spiralis consists of a single row of 45 to 55 stichocytes. Each stichocyte is about 25 mum in diameter and possesses a single nucleus. A duct leads from each stichocyte to the lumen of the esophagus. The stichocyte cytoplasm contains mitochondria, structures resembling Golgi-complexes, rough...

Ultrastructural changes which occurred in infected skeletal muscle fibers after infection with larvae of Trichinella spiralis were followed on a daily basis utilizing synchronous infections. No changes were observed in muscle fiber architecture during the first 2 days of intracellular infection. However, on Day 3, a space containing various sarcopl...

Newborn larvae of Trichinella spiralis were infective when injected directly into the thigh muscle of mice and rats. Infections initiated in this manner resulted in synchronously growing populations of muscle larvae, thereby permitting a detailed study of larval growth to be carried out.In mice, the mean larval growth, as measured by increase in la...

Parenteral infections of T. spiralis did not result in increased levels of circulating eosinophils. Enteral infections terminated with the drug methyridine prior to the adult stage also resulted in no increase of circulating eosinophils. However, enteral infections terminated with methyridine after adult development but prior to larval production d...

A rapid, accurate immunodiagnostic test for trichinosis has been developed. The test employs particle associated antigens derived from cell free homogenates of muscle larvae of Trichinella spiralis in the technique of counterelectrophoresis (CE). A supplementary test using agar gel diffusion (AGD) serves to confirm results obtained by CE. Using the...

Populations of an insect-parasitizing nematode, Neoaplectana glaseri Steiner, 1929, were exposed to actinomycin-D and puromycin-HCl in an axenic, liquid culture medium. Actinomycin-D, a known inhibitor of RNA synthesis, affected the nematode's developmental growth and reproduction but failed to alter the exsheathement of third-stage larvae, the ini...

Viable newborn larvae were used in several related series of experiments dealing with acquired immunity in rats. In the first study, newborn larvae were tested for their ability to induce immunity. It was shown that rats infected iv with newborn larvae had a 95% reduction in the number of muscle larvae deposited from an oral challenge infection as...

A method is described for the isolation of large numbers of newborn larvae from adult Trichinella spiralis. These isolated larvae were used in experiments which tested their ability to infect mice via the intraduodenal, intravenous, and intraperitoneal routes, and to infect rats via the intraperitoneal and intravenous routes. Encysted muscle larvae...

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The relationship between length of exposure in mice to Trichinella spiralis larvae in diffusion chambers and the level of resistance against trichinosis was analyzed. The number of recovered muscle larvae was inversely proportional to the length of exposure. However, no further reduction in the numbers of muscle larvae occurred after five days of i...

Virgin females of Aedes aegypti are inseminated only once. Subsequent insemination is inhibited by a substance from the male accessory gland that is transferred to the female in seminal fluid at the initial mating. This substance, called ‘matrone’, can be extracted from the whole bodies of male mosquitoes. Injection of matrone into females renders...

Mice exposed for 7 days to Trichinella spiralis larvae in diffusion chambers, were found to be immune to challenge infections. Immunity was reflected by a significant reduction of muscle larvae and adults. Immunity persisted for at least 6 months after removal of the diffusion chambers. Diffusion chambers allow the investigator to control length of...

The antibody binding sites of the larva of Trichinella spiralis were investigated using the ferritin-conjugated antibody technique. It has been shown from this study that ferritin-conjugated hyperimmune gamma globulin produced during the course of infection, attached specifically to the outer surface of the cuticle. Nonimmune ferritin-conjugated ga...