Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Isoptera”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

522 records · Page 29Linked to original sources
PubMedDate not supplied

BIOLOGY OF TERMITES.

Explore the source record for details and available documents.

Animals↗
PubMed2004

[Ultrastructural basis of interactions between prokaryotes and eukaryotes in different symbiotic models].

This paper reviews the Author's contribution to the knowledge of the ultrastructural basis of the prokaryote-eukaryote interactions in different models assessed by an ultrastructural approach. In agreement with the hypothesis of the origin of eukaryotic cells, which are chimeras of several prokaryotes with different morpho-functional specializations, symbiosis had major consequence for evolution of life. In Arthropods, one of the most successful lifestyles, the presence of endosymbiotic prokaryotes, plays an important role in their metabolism. In some cases, genome integration has occurred in the endosymbiotic relationships with the host, proving that intracellular symbiosis is not merely a nutritional supplement. Intracellular symbiotic bacteria are also described in nematodes. In particular, the presence of intracellular Wolbachia in filariae, even if its function is not yet completely known, influences positively the reproductive biology and the survival of the host, as proved by antibiotic treatment against this bacterium. The ultrastructural images reported in this review were obtained using different species of cockroaches, termites, ticks and filarial nematodes. The traditional methods of transmission (TEM), scansion (SEM) and immuno electron microscopy were used. In addition, also freeze-fracture and deep-etching techniques were employed. The cockroaches and the primitive termite Mastotermes darwiniensis host symbiotic bacteria in the ovary and in specialized cells (bacteriocytes) of the fat body. These bacteria have the typical cell boundary profile of gram-negative bacteria and are enveloped in a vacuolar membrane produced by the host cell. Molecular sequence data of 16S rDNA of endosymbionts of five species of cockroaches and M. darwiniensis indicate that they are members of the Flavobacteria-bacteroides group and that the infection occurred in an ancestor common to cockroaches and termites probably after the end of the Paleozoic (250 Ma BP). The symbiotic bacteria are transmitted transovarially and, during embryogenesis, they are integrated into the morphogenetic processes. In particular, we were able to demonstrate that the origin of the bacteriocyte should be looked for in the cells of the haemocyte line (embryonic plasmatocytes). The eggs are infected by the bacteria emerging from the bacteriocytes of the ovaric fat body and, at the end of the vitellogenesis, they are actively phagocytized by the egg membrane. In filarial nematodes, intracellular bacteria belonging to the genus Wolbachia have been described: they have evolved an obligatory mutualistic association with their host. In fact, antibiotic treatments lead to the clearance of bacteria and this loss produces a negative impact on reproduction and survival of the filarial host. We evidenced, by TEM, the degenerative events occurring during the embriogenesis of Brugia pahangi and Dirofilaria immitis after tetracycline treatment. The data suggest that the Wolbachia play a direct role in worm metabolism. Finally, a new additional model of the prokaryote-eukaryote interaction has been described: we have recently discovered a new intracellular alpha-proteobacterium, named Iric ES1, which resides in the ovarian tissues of the tick Ixodes ricinus. The intriguing characteristic of this bacterium is its ability to invade and consume the ovaric mitochondria. From an evolutionary perspective, it is interesting to note that Iric ES1 enters mitochondria in a similar way to that employed by the "predatory" bacterium Bdellovibrio bacteriovorus.

Animals↗
PubMed2004

Enhancement of pathogenicity of Bacillus thuringiensis by gamma rays.

Studies were conducted on the enhancement of pathogenicity of Bacillus thuringiensis by gamma rays on various species of termites. The results showed that the 72 hrs old and 60 or 70 kr irradiated culture of B. thuringiensis were more pathogenic than the non-irradiated ones. 168 hrs old and 150 kr (1.5 kGy) irradiated B. thuringiensis caused quicker mortality rate than the non-irradiated one as it shows maximum enhancement ratio (1.32).

Animals↗
PubMed2005

[Immunocytochemical localization of c-fos protein in termite brains following flying behavior].

The expression of c-fos protein was examined in the brain of reproduction termite (Reticulitermes aculabialis) with immunocytochemical localization method. The results showed c-fos protein immunoreactivity was found in the procerebrum, deutocerebrum and tritocerebrum of termites at all stages. At last instar nymph and after flying stage, c-fos immunoreactivity of procerebrum was weak, but the female and male termites displayed significantly increased the number of c-fos labeled cells in the protocerebrum at flying stage. On the other hand, previous studies have demonstrated neural cells of procerebrum could strongly secrete FSH (Follicle Stimulating Hormone) and LH (Luteinizing Hormone) which maintained libido and stimulated mating flight. This meaned that c-fos expression of procerebrum involved in hormone regulation in sexual behavior,as have been shown in mammal. In conclusion, we demonstrated here for the first time that c-fos expression of procerebrum of termites involved in sexual behavior. These resulats provided a new morphological proof that neural activation of procerebrum participated in the regulation of sexual behavior of termites.

Animals↗
PubMed2005

Toxicological study of plant extracts on termite and laboratory animals.

Toxic activity of leaf extracts of Polygonum hydropiper L. and Pogostemon parviflorus Benth. were tested in the laboratory against tea termite, Odontotermes assamensis Holm. Both the tested extracts caused mortality of the termite. The highest toxic activity (100%) was found in the 2.0% chloroform extracts of P. hydropiper. The chloroform extract of P. hydropiper was explored for possible mammalian toxicological effects. The LD50 was 758.58 mg/kg in male albino mice. Subcutaneous injection of sub-lethal dose of extract into male mice once a week for 6 weeks failed to express any significant influence on WBC, RBC count and blood cholesterol.

Animals↗
PubMed2005

[Immunocytochemical localization of estrogen receptor in the oogenesis of termites].

The expression of estrogen receptor(ER) was examined in the oogenesis of termites (Reticulitermes aculabialis) with immunocytochemical localization method. The results showed ER existed in oocytes at the process of differentiation and the process of growth. ER immunopositive substance was localized in the nucleus of oocytes at the differentiation stage and (the cytoplasm of oocytes at the growth stage. On the other hand,previous studies have demonstrated the procerebrum of termites could secrete FSH (Follicle Stimulating Hormone)and LH (Luteinizing Hormone) which stimulated estrogen secreting. These results provide a new morphological proof that "brain-gonad" participates in the regulation of the oogenesis of termites, as have been shown in mammal.

Animals↗
PubMed2005

[Study of water-soluble compounds from fungus garden of Odontotermes formosanus].

OBJECTIVE: To study water-soluble compounds from fungus garden of Odontotermes formosanus. METHODS: The chemical constituents of fungus garden were analyzed and identified by GC-MS. RESULTS: 28 compounds were separated and 11 chemical constituents were identified. CONCLUSION: The main constituents in water-solubles from fungus garden of Odontotermes formosanus are palmitic acid, linolei acid and oleic aid.

Animals↗
PubMed2006

[Diversity and function of symbiotic microbes in the gut of lower termites].

The gut of lower termites harbor a complex microbial community, including eukaryotic flagellates and prokaryotic bacteria and archaea, which play important roles in the wood-cellulose digestion of these termites. The hindguts of lower termites are characterized with an enlarged paunch with steep oxygen and hydrogen gradient and not randomly distributed abundant microorganisms. The symbiotic flagellates in the gut of lower termites, which are normally associated with epibionts or endobionts, are phylogenetically affiliated with Trichomonadida, Hypermastigida and Oxymonadida. They endocytose wood particles and ferment the polysaccharide components to acetate, CO2 and H2, which are further metabolized by symbiotic prokaryotes as energy and nutrition sources in the termites. Cellulose genes such as glycosyl hydrolase family 45 have been identified in gut protists with molecular approach. Phylogenetic analysis have revealed that in the gut of lower termites, such as several Reticulitermites species, most of the dominant bacteria belong to phyla like "Termite group 1", Spirochaetes, Firmicutes, Bacteroidetes, and Proteobacteria. These bacteria clones normally form distinct termite clusters in phylogenetic trees, which show the existence of specific microbial diversity in the termite guts. Most of the symbiotic archaea in the gut of lower termites are methanogens and affiliated with the genus Methanobrevibacter by phylogenetic analysis and pure culture. The symbiotic bacteria and archaea may involve in the reduction of CO2 and the metabolism of N2 in these termite guts. However, the functions and metabolic mechanisms of the symbiotic flagellates and prokaryotes in the gut of lower termites are still remaining to be further elucidated.

Animals↗
PubMedDate not supplied

[Diazotrophs in the digestive tract of termite Neotermes castaneus].

Normal vital activity of termites Neotermes castaneus requires the presence and continuous replenishment of transient nitrogen-fixing bacteria in their digestive tract, which is realized by coprophagy and repeated utilization of substrate enriched in termite feces. This is the first demonstration of significant changes in the complex of aerobic and facultatively anaerobic nitrogen fixers mediated by an extension of microbial group composition and a shift in dominant taxa in termites that cannot reutilize their feces.

Animals↗