Studies on the fine structure of the protozoan Cyclidium,with special reference to the mitochondria,pellicle and surface-associated bacteria

Summary The ultrastructure of Cyclidium, including the cilia, kinetosomes, pellicle, microtubules and kinetodesmal fibers is similar to that recorded for other ciliates. Of special interest is the attachment of rod-shaped bacteria within the longitudinally directed shallow surface folds of the protozoan. Both the bacteria and the surface of Cyclidium seem to possess an outer coating of a sticky substance which upon contact holds the bacteria to the protozoan. The bacteria appear to be attached by only a relatively small area of their surfaces. A dense substance appears within the alveolus of the pellicle at the regions of the attachment of the bacteria. The association of the organisms is probably a temporary one, and it is unknown whether either organism is benefited or harmed by the association. The position of the mitochondria in Cyclidium is unusual in that they all lie flattened against the inner membrane of the pellicle, usually in a position directly opposite to that of the attachment of the bacteria to the surface, thus being separated from the bacteria by only the outer cell membrane and the pellicle. Whether or not this close topographical relationship is of significance is unknown.We are indebted to Dr. Dorothy Pitelka for help in determining the identity of certain membranes and microtubular structures in Cyclidium.     

Protozoan communities around conifer roots colonized by ectomycorrhizal fungi

Protozoan communities around roots with different types of ectomycorrhizae were distinct. These protozoan communities differed both qualitatively and quantitatively with the host (Pinus ponderosa, Pseudotsuga menziesii, Picea sitchensis, Tsuga heterophylla and Abies grandis) and the ectomycorrhizal fungal species. Based on the species identified and the numbers of individuals of each species, six communities of protozoa were found associated with specific ectomycorrhizae. Previous researchers have shown that mycorrhizal colonization of roots alters the amounts and types of exudates produced by roots, which in turn alters the bacterial community present. Most likely, mycorrhizal colonization of roots influences the protozoan community around roots by controlling the bacterial community. However, the protozoan community may in turn influence the successional dynamics of ectomycorrhizal fungi on different host root systems by a variety of mechanisms. These mechanisms could include: (1) preying upon individuals and perhaps removing particular species of bacteria from the mycorrhizosphere; and (2) controlling nitrogen mineralization in the rhizosphere. Further work needs to be performed to determine the interaction between these quadrate (plant-bacteria-fungi-protozoa) associations.     

Tritrichomonas foetus: ultrastructural localization of basic proteins and carbohydrates

The postformalin ammoniacal silver (AS) and the ethanolic phosphotungstic acid (E-PTA) techniques were used to localize basic proteins at the ultrastructural level in the protozoa, Tritrichomonas foetus. The periodic acid-thiosemicarbazide-silver proteinate technique was used to localize carbohydrates. With the AS technique reaction product was seen only in the hydrogenosomes. With the E-PTA technique, reaction product was seen in the microtubules that form the basal bodies, flagella, pelta, and axostyle, in the costa, in the hydrogenosomes, and at the region of the recurrent flagellum's adhesion to the cell body. Previous acetylation of the cells under conditions that block most free amino groups abolished (AS technique) or greatly reduced (E-PTA technique) staining. Carbohydrates were localized on the cell surface; in the membranes of the hydrogenosomes, Golgi complex, and cytoplasmic vesicles; and in the glycogen particles. The specificity of the AS and E-PTA techniques to detect basic proteins is based on observations made with T. foetus as well as with other cell types.     

Behavioural and toxic effects of termite defensive secretions on ants

ABSTRACT. The toxicity and biological activity of the defensive secretions of ten species of neotropical termites were examined by bioassay on two species of predatory ant. Pseudomyrmex termitarius (F. Smith) (Pseudomyrmecinae) was more susceptible to the effects of the secretions than Ectatomma sp. (Ponerinae). The bioassay results show a progression in the nature of termite chemical weaponry and in the potency of defensive secretions. The tacky secretions used by Coptotermes and Ruptitermes are simply adhesive, entangling agents with no apparent toxic or pheromonal properties. The secretion of Syntermes calvus Emerson serves as a wound-active poison with little topical activity, while those of Armitermes spp. are repellent to ants and show activity as topical poisons. The secretions used by Nasutitermes spp. combine adhesive, entangling properties with the toxicity of a topically-active poison, and are effective also as ant-repellents.     

家白蚁氨基酸含量及其在初建群体形成过程中变化的测定初报

对家白蚁Coptotermes formosanus Shiraki雌雄繁殖蚁在初建群体形成过程中氨基酸含量变化的测定,初步认为与产卵、哺育幼蚁和交尾有密切关系。产卵高峰期、哺育幼蚁期和交尾期氨基酸含量骤然下降,而产卵间歇期又开始回升。同时发现,雌雄蚁体重的变化对氨基酸含量的变化没有明显影响。     

Trypanosoma brucei: biochemical and morphological studies of cytotoxicity caused by normal human serum

The biochemical and morphological events which accompany lysis of Trypanosoma brucei by normal human serum have been described. The prelytic events include loss of infectivity and rapid cation shifts across the cell membrane. This is followed by cell swelling, fraying of the surface coat of the cell, loss of intracellular organelles, and eventually cell lysis. The data presented are consistent with a colloid osmotic mechanism of lysis induced by irreversible acute damage to the normal permeability properties of the trypanosome plasma membrane.     

Direct potentiometric determination of redox potentials of the gut contents in the termites Zootermopsis nevadensis and Cubitermes severus and in three other arthropods

A Pt and calomel electrode combination were used to determine the redox potentials of the gut contents in two termites, Zootermopsis nevadensis and Cubitermes severus. Strongly reducing conditions occurred in the paunch of Z. nevadensis (mean E_h = ?160 mV), consistent with many evidences that anaerobic fermentation of wood polymers occurs at this site. In C. severus, a soil-feeder, equivalent regions of the hindgut were more midly reducing (P1: mean E_h = ?104 mV; P3: mean E_h = ?47 mV) while the colon appeared microaerobic or aerobic. It is argued that these conditions are more appropriate to the digestion of humic materials. Potentials consistent with aerobic conditions were found throughout the guts of Periplaneta americana, Locusta migratoria and Glomeris marginata, although the cockroach hindgut was more reducing than the equivalent structures in the other non-termite species.     

Ectobiotic spirochetes of flagellates from the termite Mastotermes darwiniensis: attachment and cyst formation

The association of the gut flagellates Mixotricha paradoxa and Deltotrichonympha sp. from the termite Mastotermes darwiniensis with ectobiotic spirochetes and bacterial rods is investigated with light and electron microscopy. Treatment with different chemicals disturbing molecular interactions and use of the freeze-fracture and freeze-etch technique show that hydrophobic interactions and integral membrane proteins seem to be involved in the firm attachment at the contact sites. Application of antibiotics reduces the number of ectobionts and leads to a disintegration of the cortical attachment systems. As a result Mixotricha becomes spherical and immotile. In both flagellates the antibiotics have a further effect: they lead to a transformation of some of the spirochetes into cystic bodies. Cyst formation of ectobiotic spirochetes is here reported for the first time. Starvation has a similar but less dramatic influence than antibiotics. The cysts contain protoplasmic cylinders in the periphery and sometimes larger central bodies. Production of dormant cystic forms may be a survival mechanism under hostile conditions.     

原虫的蛋白质组学研究进展

随着“人类基因组计划”的完成,包括双向电泳和质谱技术的蛋白质组学作为基因组学研究的补充和终点,不断增加我们对基因功能的理解,逐渐成为医学研究的中心。原虫作为医学研究的对象和工具,研究内容十分广泛。本文将从原虫生活史、致病机理、潜在疫苗以及抗药性等方面对原虫的蛋白质组学进行综述。     

四川省树螱四新种(等翅目:木螱科)

直颚树螱Glyptotermes orthognathus Ping et Chen,兵（尉虫） （图1）体小型。头黄褐色,额面稍淡,上颚紫褐色,上唇、触角淡黄褐色,前胸背板和腹部淡黄白色,足腿节、胫节同腹部,跗节黄色。     

Salivary gland of the tick vector of East Coast fever. III. The ultrastructure of sporogony in Theileria parva

Sporogony of the sporozoan Theileria parva in the salivary gland of the tick vector of East Coast fever was studied in electron micrographs. The findings differ in several respects from previous interpretations based upon light microscopy. Cytokinesis of the primary sporoblast to form secondary and tertiary sporoblasts is not substantiated. Instead it is suggested that the parasite develops as a ramifying, multinucleate syncytium rapidly increasing in size and complexity until it gives rise to myriad sporozoites in a terminal episode of cytoplasmic fission. The proliferating nuclei initially occupy peripheral lobules that are continuous with a central labyrinth of branching and anastomosing processes which present a very large surface area for interchange of metabolites with the host cell cytoplasm. The membrane of the labyrinth is rich in cytostomes, but no evidence if found to bulk uptake of host cytoplasmic matrix or organelles into food vacuoles. Rhoptries are the first of the polar organelles of the parasite to develop and are associated with dense plaques irregularly distributed on the inner aspect of the parasite membrane. Micronemes form independently of the rhoptries at a later stage. After 3-4 days of tick feeding, sporogeny is complete and the infected salivary gland cell contains up to 50, 000 spherical or ovoid sporozoites about 1 micrometer in diameter. These are limited by a simple plasma membrane. The inner layer of the 'pellicle', the polar ring, and the conoid described for zoites of other Apicomplexa are lacking. Maturational changes are noted in sporozoites after sporogony is completed. Micronemes appear to increase in size, and possibly in number, from days 3-5 and the majority take up positions immediately subjacent to the plasmalemma.     

Influence of methods of preparation on the infectivity, agglutination, activity, and ultrastructure of bloodstream trypanosomes

Contrary to the reports of others, the surface coat of Trypanosoma brucei brucei was not removed by extensive washing in the various media investigated; in fact, other than a deformed profile when washed in saline, ultrastructure was little affected by column separation and washing in any of these media. Washing in saline increased the agglutinability but reduced the activity and infectivity of the organisms. Washing in bicine-buffered saline-glucose did not impair activity or infectivity but increased agglutinability, albeit to a lesser extent than after washing in phosphate-buffered saline-glucose. The inclusion of 0.1% serum or plasma in the washing medium (phosphate-buffered saline-glucose or bicine-buffered saline-glucose) increased the activity of the T. b. brucei and did not increase agglutinability or impair infectivity. T. congolense and T. vivax were more susceptible to ionic strength changes than were T. b. brucei or T. lewisi, in that not only was their activity impaired, but they began to aggregate on standing in lower ionic strength buffers.     

七种白蚁消化道解剖形态的比较研究

本文对采自浙江省的7种白蚁（东方原白蚁、黄肢散白蚁、黑胸散白蚁、肖若散白蚁、家白蚁、杨之江近歪白蚁和和大鼻象白蚁）的消化道形态进行了解剖比较研究。并初步探讨了白蚁消化道形态在白蚁系统发育和进化中的意义。     

Molecular phylogeny of the Rhinotermitidae

Summary. Relationships among genera in the termite family Rhinotermitidae and their relationship to the families Termitidae and Serritermitidae were investigated based on analysis of three mitochondrial genes: COI, COII and 16S rDNA. Maximum Parsimony (MP) bootstrap analysis of each of these genes indicated a low level of phylogenetic incongruence between them, and thus they were combined and analysed by MP and Bayesian analysis. Six main lineages were clearly identified, however relationships among these were not well defined. Tentative support was found for the Rhinotermitid genera Coptotermes, Heterotermes and Reticulitermes being the sister group to the Termitidae, rendering the Rhinotermitidae paraphyletic. The species Serritermes serrifer and Glossotermes oculatus were found to group with strong support, in agreement with the recent transfer of the latter species to the family Serritermitidae based on morphological characteristics. No support was found for the Rhinotermitidae being paraphyletic with respect to the Serritermitidae. A number of disagreements were found between the molecular tree and traditional classifications of genera within subfamilies.Received 20 February 2004; revised 2 April 2004; accepted 19 April 2004.     

深圳口岩进口原木截获的白蚁（等翅目）

记录深圳口岸1998－2001年期间从进口原本中截获的3科7属12种白蚁,包括黄檀新白蚁Neotermes dalbergiae (Kalshoven),大家白蚁Comptotermes curvignathus Holmgren,塞庞乳白蚁C.sepangensis Krishna,波罗乳白蚁C.borneensis Oshima,非洲乳白蚁C.sjostedti Holmgren,沙捞越长鼻白蚁Schedorhinotermes sarawakensis (Holmgren),中暗长鼻白蚁S.mediobscurus (Holmgren),哈氏象白蚁Nastutitermes havilandi (Desneux),镰锯白蚁Microcerotermes distans (Havilandi),邻白蚁Termes propinquus (Holmgren), 印度弓白蚁Amitermes belli (Desneux)和齿弓白蚁A.dentatus (Havilandi)。编制了分种检索表,并对上述国内没有分布的白蚁种类兵蚁的形态和鉴定特征作了描述的图示。