摘要:

SYNOPSIS.The electron‐microscope study of syzygy inGregarina polymorpha, shows that this coupling, a prelude to cyst formation and to sexual phenomena, must not be considered as a simple pairing of individuals, but is rather the response of a gamont to a stimulus coming from another individual of a different sex. This response, in the species studied, can be recognized from the modifications that will appear progressively at the contact surfaces of the two gregarines. They affect only the protomerite apex of the posterior individual. There occur: rapid growth of the protomeritic epicyte; separation of this epicyte from the fibrillar zone underneath; formation of a protomeritic cup containing various inclusions; the disappearance of cuticular digitations and the formation of invaginations which become deeper and deeper.All these modifications occur as soon as syzygy starts. They seem to indicate a reaction of the satellite epicyte to a possible stimulus coming from the anterior female gamont. This epicyte could play a different part from the initial one.In the case of association between a primite and several satellites, the posterior gamonts react in a comparable manner but not togethe

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1968.tb02183.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

SYNOPSIS.The changes in young, 6‐day‐old to adult (13‐day‐old) forms ofT. lewisiduring the course of infection in rats are attended by some changes in mitochondrial enzyme activities. The most significant differences between the 2 forms are in the content of isocitric dehydrogenases (2 distinct enzymes are present), and in the ability to carry out oxidative phosphorylation. In the mitochondria of adults there is a significant decrease in the ability to f

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1968.tb02184.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

SYNOPSIS.An investigation of day‐to‐day changes in adult form antigens ofT. lewisiin the rat shows that adult antigens, 2 of which are present in trace amounts in young forms, suddenly appear in large amounts in 9‐day‐old trypanosomes. An additional antigen is formed on the 13th day. In addition, 2‐day‐old trypanosomes contain some antigens not present in 6‐day‐old forms. The combined results of the present paper and a previous one indicate that there are antigenically 3 distinct stages ofT. lewisiin the rat: 1‐ to 3‐day‐old, 4‐ to 8‐day‐old, and 9‐ to 14‐day‐old forms. From 9‐ to 11‐day‐old trypanosomes, there is a form c

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1968.tb02185.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

SYNOPSIS.A new coccidiumSivatoshella lonchuraen. gen., n. sp. (Coccidia, Eimerüdae) is described from the gut of the passeriform birdsLonchura malabarica(Linn.) andL. punctulata(Linn.). Endogenous stages of the parasite conform to those of the family Eimerüdae. Oocysts are spherical, 36–38 μ (avg. 37.5 μ) in diameter. Wall 3.6 ä thick, 4‐layered; outermost layer thin transparent and colorless; next, slightly broader and light green; 3rd, thinner and light yellow; innermost dark black. Oocyst residuum absent. Micropyle absent. Sporocysts 28–29 μ long and 18 μ wide. They are 2 broad pear‐shaped bodies with Steida body and a prominent substeidal body at the narrow pole. Sporocyst residuum present as minute refractile globules embedded in a dark matrix. Sporozoites broad, comma‐shaped, with one large vacuole at the broad pole and nucleus at the center of the body. Sixteen sporozoites in each sporocyst, arranged at the periphery of the residual mass.Sporulation time: 24–48 hours at 31 C.Habitat:duodenum and small intestine ofLonchura malabarica(Linn.) andL. punctulata(Linn.).Locality:Calcutta

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1968.tb02186.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

SYNOPSIS.Cytoplasmic extracts ofParamecium aureliawere fractionated by density gradient centrifugation. The gradient fractions were characterized by chemical analysis and electron microscopy. Membrane‐bound ribosomes were separated from free polyribosomes and the ability of each of these forms to incorporate C14‐leucine into protein was tested. Incorporation was measured in both invivoandin vitrosystems, and similar results were obtained in both types of experiment except that there was little release of soluble labelled protein in thein vitrosystem.Parameciumappears to synthesize most of its protein on free polyribosomes but membrane‐bound ribosomes constitute an important protein synthetic fraction, perhaps accounting for as much as 30% of the total synthesis. When isolated in thein vitrosystem, increasing concentration of the ribosome fraction gave increased incorporation, but increasing concentration of the membrane fraction gave decreased incorporation after a critical value. This inhibitory effect can be removed by adding excess cytoplasmic‐supernatant to the system. The nature of the association of ribosomes with membranes is di

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1968.tb02187.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

SYNOPSIS.Two new species of small amebae, Hartmannella biparia n. sp. and Hartmannella quadriparia n. sp., were 1st observed in the freshwater mollusks Bulinus globosus and Biomphalaria pallida, respectively. The amebae multiplied in cytoplasmic vacuoles in host cells, particularly in foci in the mantle collar, foot, and intestinal wall. Both amebae had functional contractile vacuoles while within host cells. H. biparia emerged from intracytoplasmic vacuoles in pairs, H. quadriparia in fours, suggesting characteristic reproductive stages.H. biparia had limax‐type motility by smooth lobopodia, was 22 μ long; with vesicular nucleus 3 μ and central endosome 1.5 μ, multiplied by binary fission and formed spherical, smooth‐walled cysts 11 μ in diameter. H. quadriparia had limax‐type motility by lobopodia with fine, acute projections; was 10 μ long, with vesicular nucleus 2 μ and central endosome 0.75 μ, multiplied and formed spherical, smooth‐walled cysts 5 μ in diameter. Neither species multiplied in cysts outside the host.H. bipariawas found infecting 12 species and experimentally transferred to 4 more species of freshwater snails; H. quadriparia was found in one species and experimentally transferred to

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1968.tb02188.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

SYNOPSIS.Protozoa of the order Euglenida contain a polysaccharide storage product, paramylon, composed of 1, 3‐linked glucose molecules arranged into an extremely resistant granule. An enzyme was purified from the soluble phase ofEuglena graciliswhich would degrade this polysaccharide to single glucose residues, providing the integrity of the paramylon granule was 1st disrupted by dilute base. This enzyme, a β‐1, 3 glucanase, had optimal activity at pH 5.0 and 60 C and bound tightly to base‐disrupted paramylon substrate tho not to the intact granules. The specific activity of the enzyme was doubled when cell cultures reached stationary phase, the phase where net carbohydrate utilization began. An ATP‐dependent hexokinase reaction was also present inEuglenahomogenate. No phosphorylase activity has been found inEuglena.It is suggested, therefore, thatEuglenado utilize their paramylon as a carbohydrate reserve and the mechanism of this utilization is by exo‐hydrolytic cleavage to free glucose followed by phosphorylation and

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1968.tb02189.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

SYNOPSIS.After 1914 protozoologists have generally agreed thatPleistophora gigantea(Thélohan, 1895) Swellengrebel, 1911,Ichthyosporidium giganteum(Thélohan, 1895) Swarczewsky, 1914, andI. phymogenesCaullery and Mesnil, 1905, are identical. Because no polar filament was found in the spores, however, some authors have followed Swarczewsky in considering this species to be a haplosporidan, while others have persisted in thinking it a microsporidan. Using preserved material that Swellengrebel saved from a tumor on which he based his studies, we have found a polar filament in the spores both with the PAS reaction and with the electron microscpe. This new information removes the only basis for the doubt which some authors have entertained, that Thélohan and Sweliengrebel correctly considered the parasite to belong to the Microsporida. SincePleistophora giganteais believed to be identical withI. phymogenes, recently selected by Sprague as type species of genusIchthyosporidiumCaullery and Mesnil, 1905, thenIchthyosporidium, originally assigned to the Haplosporida, must be regarded as a microsporidan genus. Whether it is distinct from all other microsporidan genera is a matter needing further considerati

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1968.tb02190.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

SYNOPSIS.Tokophrya infusionumreproduces by endogenous budding, forming a ciliated embryo within a brood pouch. The embryo is released to the outside medium, where it swims for some time, then undergoes metamorphosis by the formation of a disk, stalk, and tentacles. In one of the clones (E22), 1–2% of the adults display abnormalities during reproduction. In some of the abnormal adults, the embryo is retained inside a greatly enlarged brood pouch and undergoes metamorphosis within the parent; in others, the embryo is not formed, and only a large empty brood pouch appears. Attempts to establish a separate clone composed only of abnormal organisms were unsuccessful, and led to the conclusion that all members of clone E22 are potentially abnormal. Experiments were performed to increase the percentage of abnormal organisms; it was found that overfeeding is one of the factors favoring abnormal reproduction. Physiological and genetic explanations of the abnormality are proposed and discusse

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1968.tb02191.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

SYNOPSIS.The behavior of the amoebaH. castellaniiwas investigated in various carbon and nitrogen deficient media with a view to developing a satisfactory replacement medium for the study of encystment and excystment. Media which had been devised for other soil amoebae did not causeH. castellaniito encyst. In these media there was an efflux of material from the cells which was independent of osmolarity but which was minimized by the addition of magnesium. Maximal encystment occurred in a medium containing magnesium chloride alone.The cysts produced in the magnesium chloride replacement medium are viable and readily excyst when resuspended in the growth medium. The cysts contain cellulose, which is not present in the vegetative amoebae, and differ from the amoebae in their greater resistance to induced lysis and mechanical injury.

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1968.tb02192.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY