161.
Sterol biosynthesis in the free-living nematode Panagrellus redivivus
- Willett, James D.; Downey, William L.
The fate of the known sterol precursor squalene 2,3-oxide was investigated in the free-living nematode Panagrellus redivivus. The nematodes were cultured axenically in the presence of [4-3H]squalene 2,3-oxide. Radioactivity was found in the total lipids of the isolated nematodes. Essentially all of the radioactivity encountered in the total lipids was found in the non-saponifiable fraction. The components present in the non-saponifiable fraction were separated and isolated by t.l.c. Three labelled components were identified by a combination of t.l.c., g.l.c. and mass spectroscopy. It is established that P. redivivus has the capacity for biosynthesis of lanosterol. No labelled C27 sterols could...
162.
Anthelmintic activity of methyridine against experimental nematode infections in mice
- Broome, A. W. J.; Greenhalgh, N.
Critical studies using mice infected experimentally with nematodes (Nematospiroides dubius, Nippostrongylus muris and Heterakis spumosa) have shown methyridine to be an extremely effective anthelmintic when administered orally or subcutaneously. Comparisons of the two treatment regimes show subcutaneous administration to be the more efficient in terms of absolute dose, but neither treatment has a significant advantage in therapeutic safety margin. Methyridine has a more uniform anthelmintic action than either phenothiazine or bephenium against adult forms of the three test nematodes. In addition the drug possesses activity against all stages of certain immature nematode infections.
163.
Los Nematodos Entomopatógenos (Rhabditida: Steinernematidae y Heterorhabditidae) presentes en Cataluña y su utilización para el Control Biológico de Insectos
- García del Pino, Fernando
Se ha estimado la presencia de los nematodos entomopatogenos en Cataluña, evaluando su aparición en función de la situación geográfica, las condiciones climáticas y el tipo de hábitat analizado (cultivo, prado natural y bosque). Se han analizado los factores edaficos, climáticos y culturales que determinan la presencia y persistencia de los nematodos entomopatogenos en los suelos de cultivos. Se han determinado las especies de nematodos entomopatogenos de las familias steinernematidae y heterorhabditidae presentes en Cataluña, valorando los caracteres morfológicos que permiten su diferenciación y estudiando la variabilidad existente entre las diversas cepas de cada especie. Finalmente se ha evaluado la...
164.
Entomopathogenic nematodes: potential for exploration and use in South America
- GREWAL,PARWINDER S.; NARDO,ELIZABETH A. B. DE; AGUILLERA,MARINEIDE M.
Entomopathogenic nematodes have potential for biological control of insect pests. They are currently used for the control of soil and cryptic pests in North America, Europe, Asia and Australia. Entomopathogenic nematodes can be easily mass-produced and applied using conventional spray equipment. They have a broad host range and are safe to the environment. Due to the history of success with implementation of biological pest control programs, South American countries have a great opportunity to develop and implement the use of entomopathogenic nematodes. Recent emphasis on fruit and vegetable production in Brazil also stresses a need to implement safer and effective...
165.
On the evolution of early development in the Nematoda.
- Goldstein, B
The phylum Nematoda serves as an excellent model system for exploring how development evolves, using a comparative approach to developmental genetics. More than 100 laboratories are studying developmental mechanisms in the nematode Caenorhabditis elegans, and many of the methods that have been developed for C. elegans can be applied to other nematodes. This review summarizes what is known so far about steps in early development that have evolved in the nematodes, and proposes potential experiments that could make use of these data to further our understanding of how development evolves. The promise of such a comparative approach to developmental genetics...
166.
Nuevos hospedadores y registros geograficos de Pterygodermatites (Paucipectines) kozeki (Nematoda, Rictulariidae) en Argentina
- Ramallo,Geraldine; Claps,Lucía E.
Pterigodermatites (Paucipectines) (Nematoda: Rictulariidae) incluye cinco especies parásitas de edentados, marsupiales y roedores cricétidos. En esta nota se registra por primera vez a Pterigodermatites (Paucipectines) kozeki (Chabaud y Bain, 1981) Navone, 1989, como parásito de Thylamys pallidior y Thylamys venustus en las provincias de Salta y Jujuy (Argentina).
167.
Nuevos hospedadores y registros geograficos de Pterygodermatites (Paucipectines) kozeki (Nematoda, Rictulariidae) en Argentina
- Ramallo,Geraldine; Claps,Lucía E.
Pterigodermatites (Paucipectines) (Nematoda: Rictulariidae) incluye cinco especies parásitas de edentados, marsupiales y roedores cricétidos. En esta nota se registra por primera vez a Pterigodermatites (Paucipectines) kozeki (Chabaud y Bain, 1981) Navone, 1989, como parásito de Thylamys pallidior y Thylamys venustus en las provincias de Salta y Jujuy (Argentina).
168.
Infección por nematodos en razas de ovejas cárnicas criadas intensivamente en la región del sudeste del Brasil
- Cunha, E. A.; Veríssimo, C. J.; Santos, L E.; Oliveira, S. M.; Spósito Filha, E.; Reboucas, M. M.; Bueno, M. S.; Lara, M.A.C
En el año 2000, fueron evaluadas 35 ovejas de la raza Suffolk, 37 Île de France, 10 Poll Dorset y 31 Santa Inês, durante un año, en Nova Odessa, Estado de São Paulo, Brasil, con el objetivo de conocer el grado de infección por nematodos, el peso y la condición corporal de estos animales. Durante la cubrición y la gestación, los animales permanecieron en pasturas manejadas intensivamente (3540 cabezas/ha) y en el período de amamantamiento (60 días) las ovejas y los corderos fueron estabulados colectivamente. Las hembras mostraron un aumento del número de huevos de nematodos por gramo de heces...
169.
Prevalence of gastrointestinal nematodes in dairy heifers in western Canada
- Cox, William R.; Lemiski, David
A survey was conducted to estimate the prevalence of gastrointestinal nematodes in grazing dairy replacement heifers in western Canada. Fecal samples were collected from 566 animals on 34 farms distributed over the three prairie provinces. Fecal egg counts were performed using a modified Wisconsin centrifugation technique. The overall mean farm fecal egg count was 16.0 eggs per gram feces (range 0.7-78.1 epg). Gastrointestinal nematodes were demonstrated on every farm examined, and 93.3% of all individuals tested were positive.
170.
PSEUDOPARASITISM BY THELASTOMATID NEMATODES IN MOLES, MOGERA SPP., IN JAPAN
- YOKOHATA, Yasushi; JIANG, Yue Ping; ABE, Hisashi; OHBAYASHI, Masashi
Nine species of nematodes of Thelastomatidae were obtained from 23 of 366 specimens of moles in Japan, Mogera wogura, M. robusta and M. tokudae. Among those nematodes, eight species, Chitwoodiella ovofilamenta, Singhiella singhi, Mirzaiella asiatica, M. haroldi, Binema korsakowi, B. mirzaia, Cameronia biovata and C. multiovata are the parasites of mole-crickets, Gryllotalpa spp. Pseudonymus hydrophili is the parasite of water scavenger beetles of Hydrophilidae. Therefore, the authors considered the present case as an example of pseudoparasitism.
171.
Partição aditiva da diversidade de nematoda em lagoas costeiras : componentes espaciais e ambientais
- Pamela Ziliotto Sant Anna Flach
Additive diversity partitioning has received increasing attention of ecologists as a tool to apportioning the diversity across multiple scales and test whether each scale harbors more or less diversity than what would be expected by the random assignment of individuals to sample units. This study assessed alpha and beta diversities of nematodes in five spatial scales (from cm to km). The importance of environmental and spatial determinants of variation in nematodes composition (within and between lakes) was also evaluated. Morphospecies richness was used as a metric to estimate diversity. Using available literature data, observed Nematoda diversity was compared to patterns...
172.
Identification of a nematode chemosensory gene family
- Chen, Nansheng; Pai, Shraddha; Zhao, Zhongying; Mah, Allan; Newbury, Rebecca; Johnsen, Robert C.; Altun, Zeynep; Moerman, Donald G.; Baillie, David L.; Stein, Lincoln D.
Taking advantage of the recent availability of the whole genome sequence of Caenorhabditis briggsae, a closely related nematode to Caenorhabditis elegans, we have examined the chemosensory gene superfamily by using comparative genomic methods. We have identified a chemosensory gene family, serpentine receptor class ab (srab), which exists in both species with 25 members in C. elegans and 14 members in C. briggsae. More than 20% of these gene models are reannotated. The srab family is similar to, but distinct from, the previously described serpentine receptor class a (sra) family and shows a differential expansion in C. elegans similar to that...
173.
Evolution of small nucleolar RNAs in nematodes
- Zemann, Anja; op de Bekke, Anja; Kiefmann, Martin; Brosius, Jürgen; Schmitz, Jürgen
In contrast to mRNAs, which are templates for translating proteins, non-protein coding (npc) RNAs (also known as non-coding RNA, ncRNA), exhibit various functions in different compartments and developmental stages of the cell. Small nucleolar RNAs (snoRNAs), one of the largest classes of npcRNAs, guide post-transcriptional modifications of other RNAs that are crucial for appropriate RNA folding as well as for RNARNA and RNAprotein interactions. Although snoRNA genes comprise a significant fraction of the eutherian genome, identifying and characterizing large numbers of them is not sufficiently accessible by classical computer searches alone. Furthermore, most previous investigations of snoRNAs yielded only limited...
174.
The Pumping Mechanism of the Nematode Esophagus
- Saunders, J. Richard; Burr, A. H.
The radial orientation of the myofilaments in the nematode esophagus raises interesting questions as to how such a structure can function as a pump. A physical model of the esophagus of Ascaris lumbricoides was developed and the membrane theory of shells applied in order to relate the observed dimensional changes to myofilament force, pressure stresses, and membrane elastic constants. By stressing the excised esophagus passively with osmotic pressure, the esophagus was shown to be elastically anisotropic with the ratio of circumferential to longitudinal elastic constants, E?/El ? 2.74. When this value was incorporated, the model predicted the ratio of the...
175.
Identification of a nematode chemosensory gene family
- Chen, Nansheng; Pai, Shraddha; Zhao, Zhongying; Mah, Allan; Newbury, Rebecca; Johnsen, Robert C.; Altun, Zeynep; Moerman, Donald G.; Baillie, David L.; Stein, Lincoln D.
Taking advantage of the recent availability of the whole genome sequence of Caenorhabditis briggsae, a closely related nematode to Caenorhabditis elegans, we have examined the chemosensory gene superfamily by using comparative genomic methods. We have identified a chemosensory gene family, serpentine receptor class ab (srab), which exists in both species with 25 members in C. elegans and 14 members in C. briggsae. More than 20% of these gene models are reannotated. The srab family is similar to, but distinct from, the previously described serpentine receptor class a (sra) family and shows a differential expansion in C. elegans similar to that...
176.
Evolution of small nucleolar RNAs in nematodes
- Zemann, Anja; op de Bekke, Anja; Kiefmann, Martin; Brosius, Jürgen; Schmitz, Jürgen
In contrast to mRNAs, which are templates for translating proteins, non-protein coding (npc) RNAs (also known as non-coding RNA, ncRNA), exhibit various functions in different compartments and developmental stages of the cell. Small nucleolar RNAs (snoRNAs), one of the largest classes of npcRNAs, guide post-transcriptional modifications of other RNAs that are crucial for appropriate RNA folding as well as for RNARNA and RNAprotein interactions. Although snoRNA genes comprise a significant fraction of the eutherian genome, identifying and characterizing large numbers of them is not sufficiently accessible by classical computer searches alone. Furthermore, most previous investigations of snoRNAs yielded only limited...
177.
The Pumping Mechanism of the Nematode Esophagus
- Saunders, J. Richard; Burr, A. H.
The radial orientation of the myofilaments in the nematode esophagus raises interesting questions as to how such a structure can function as a pump. A physical model of the esophagus of Ascaris lumbricoides was developed and the membrane theory of shells applied in order to relate the observed dimensional changes to myofilament force, pressure stresses, and membrane elastic constants. By stressing the excised esophagus passively with osmotic pressure, the esophagus was shown to be elastically anisotropic with the ratio of circumferential to longitudinal elastic constants, E?/El ? 2.74. When this value was incorporated, the model predicted the ratio of the...
178.
Leucocyte recruitment during enteric nematode infection
- McDermott, Jacqueline R; Grencis, Richard K; Else, Kathryn J
Resolution of infection with the intestinal nematode Trichinella spiralis depends on the host mounting a T helper 2 (Th2) response. It is known that both mast cells and T cells play a crucial role. We have previously shown that efficient migration of mast cells to the gut during infection depends on their expression of the integrin ?7. ?7 forms a heterodimer complex with either ?E or ?4 integrin chains, ?E?7 binding to E-cadherin expressed by epithelial cells and ?4?7 binding to mucosal addressin cell adhesion molecule (MAdCAM-1) on the endothelium. We were interested to know whether dysfunctional mast cell localization...
179.
Alterações fisiologicas no algodoeiro causadas pelo nematoide Meloidogyne incognita raça 3 : influencia do nivel de inoculo e do fornecimento de nitrogenio
- Marluci Mundin Abrão
Plantas de algodão (Gossypium hirsutum) dos cultivares Acala ( suscetível) e IAC-20 (tolerante) foram avaliadas quanto .ao crescimento e variações no conteúdo de açúcares solúveis, fenóis e clorofilas, e na atividade da redutase do nitrato, quando inoculadas com diferentes níveis de inoculo (0,500 e 5.000 ovos) de Meloidogyne incognita raça 3, ou quando inoculadas com apenas um nível, mas recebendo quantidades diferentes de duas fontes (nitrato e amônia) de nitrogênio. No primeiro experimento, no qual avaliaram-se as respostas a diferentes níveis de infecção, observou-se que o cultivar Acala é bastante suscetível e o cultivar IAC-20 é moderadamente resistente. Plantas inoculadas...
180.
Chemical composition of manipueira and its potential in the control of Meloidogyne incognita on tomato crop at Western ParanÃ
- Ãrica das GraÃas Carvalho Nasu
A cultura do tomateiro à fortemente afetada por Meloidogyne incognita. As dificuldades de controle deste nematÃide enfatizam a necessidade de obtenÃÃo de mÃtodos alternativos de controle, os quais contribuam para a preservaÃÃo do meio ambiente. Manipueira à um resÃduo lÃquido gerado pela indÃstria da mandioca e encontrada em grande quantidade no Oeste do ParanÃ. Objetivou-se com o presente trabalho estudar a composiÃÃo quÃmica da manipueira produzida na regiÃo Oeste do ParanÃ, bem como o seu efeito nematicida sobre M. incognita, parasita do tomateiro nesta regiÃo. As anÃlises quÃmicas foram realizadas com manipueira caseira e industrial. As amostras de manipueira industrial...
