Ultrastructure of midgut events in the pathogenesis of Bacillus sphaericus strain SSII-1 infections of Culex pipiens quinquefasciatus larvae

1979 ◽  
Vol 25 (2) ◽  
pp. 178-184 ◽  
Author(s):  
Elizabeth West Davidson
Keyword(s):  
Culex Pipiens ◽  
Bacillus Sphaericus ◽  
Wall Layer ◽  
Peritrophic Membrane ◽  
Ground Substance ◽  
Outer Cell ◽  
Bacterial Cells ◽  
Culex Pipiens Quinquefasciatus ◽  
Larval Host ◽  
Cytoplasmic Ground Substance

The fate of Bacillus sphaericus strain SSII-1 cells ingested by Culex pipiens quinquefasciatus (= C. pipiens fatigans, C. fatigans, C. quinquefasciatus of authors; Diptera: Culicidae) larvae and the cytological events preceding death of the host were observed using electron microscopy. Bacillus sphaericus cells were digested rapidly in the anterior and central midgut. The outer cell wall layer and cytoplasmic ground substance disappeared soon after ingestion. Cytolysosomes became prominent in midgut cells as these cells gradually separated from one another. All bacteria, including B. sphaericus, were confined within the peritrophic membrane until after death of the host. Digestion by the larval host is confirmed as a possible mechanism for release of B. sphaericus toxin from the bacterial cells.

Comparative studies of the mosquito-larval toxin of Bacillus sphaericus SSII-1 and 1593

1979 ◽  
Vol 25 (11) ◽  
pp. 1227-1231 ◽  
Author(s):  
Paula Myers ◽  
Allan A. Yousten ◽  
Elizabeth W. Davidson
Keyword(s):  
Inclusion Body ◽  
Comparative Studies ◽  
Culex Pipiens ◽  
Strain Differences ◽  
Growth Cycle ◽  
Bacillus Sphaericus ◽  
Toxic Activity ◽  
Thin Sections ◽  
Culex Pipiens Quinquefasciatus

Two strains of Bacillus sphaericus, SSII-1 and 1593, were bioassayed for toxic activity against second-instar larvae of the mosquito Culex pipiens quinquefasciatus. It was found that strain 1593 developed a level of toxicity 3000 times that of strain SSII-1. Although the toxic activity of B. sphaericus SSII-1 was relatively unchanged throughout growth, an increase in activity of strain 1593 occurred as the bacteria began to sporulate. Strain differences were examined by (i) growth cycle experiments, (ii) bioassays of the toxicity of oligosporogenous mutants, and (iii) manganese limitation experiments. The toxin of strain 1593 was shown to be more stable than that of strain SSII-1. Unlike the spores of strain SSII-1, the spores of B. sphaericus 1593 were found to be highly toxic. Thin sections of SSII-1 or 1593 cells did not reveal the presence of any inclusion body that might be related to toxicity.

scholarly journals Interleukin 1 beta is localized in the cytoplasmic ground substance but is largely absent from the Golgi apparatus and plasma membranes of stimulated human monocytes.

1988 ◽  
Vol 167 (2) ◽  
pp. 389-407 ◽  
Author(s):  
I I Singer ◽  
S Scott ◽  
G L Hall ◽  
G Limjuco ◽  
J Chin ◽  
...  
Keyword(s):  
Golgi Apparatus ◽  
Plasma Membranes ◽  
Secretory Pathway ◽  
Secretory Granules ◽  
Interleukin 1 ◽  
Subcellular Location ◽  
Ground Substance ◽  
Outer Cell ◽  
Human Monocytes ◽  
Cytoplasmic Ground Substance

The subcellular location of IL-1 beta was determined using a postsectioning immunoelectron microscopic method on ultrathin frozen sections of human monocytes stimulated with LPS. This methodology permits access of antibody probes to all sectioned intracellular compartments, and their visualization at high resolution. Staining was performed with a rabbit antibody that specifically recognized amino acids 197-215 in the 33-kD IL-1 beta precursor molecule, followed by affinity-purified goat anti-rabbit IgG conjugated to 10 nm colloidal gold particles. Approximately 90% of the IL-1 beta antigens were localized in the ground substance of the cytoplasm at 4 or 20 h after activation, when both intracellular and extracellular accumulation of IL-1 beta was well underway. No significant IL-1 beta staining was observed on the outer cell membrane, nor within the lumens of the endoplasmic reticulum (ER), the Golgi apparatus, or secretory vesicles. In contrast, lysozyme was localized in the ER and dense secretory granules using these methods. Our results suggest that IL-1 beta is not anchored on the plasma membrane, and that its secretion occurs by a novel mechanism that does not use a secretory leader sequence, nor the classical secretory pathway involving the ER and Golgi apparatus.

Organisation in the Structure of the Cytoplasmic Ground Substance

1978 ◽  
Vol 36 (3) ◽  
pp. 627-639
Author(s):  
K.R. Porter
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Complex ◽  
Random Distribution ◽  
Ground Substance ◽  
The Matrix ◽  
Cell Processes ◽  
Cytoplasmic Ground Substance

Most types of cells are known from their structure and overall form to possess a characteristic organization. In some instances this is evident in the non-random disposition of organelles and such system subunits as cisternae of the endoplasmic reticulum or the Golgi complex. In others it appears in the distribution and orientation of cytoplasmic fibrils. And in yet others the organization finds expression in the non-random distribution and orientation of microtubules, especially as found in highly anisometric cells and cell processes. The impression is unavoidable that in none of these cases is the organization achieved without the involvement of the cytoplasmic ground substance (CGS) or matrix. This impression is based on the fact that a matrix is present and that in all instances these formed structures, whether membranelimited or filamentous, are suspended in it. In some well-known instances, as in arrays of microtubules which make up axonemes and axostyles, the matrix resolves itself into bridges (and spokes) between the microtubules, bridges which are in some cases very regularly disposed and uniform in size (Mcintosh, 1973; Bloodgood and Miller, 1974; Warner and Satir, 1974).

scholarly journals Screening of Chemosterilants against the Southern House Mosquito Culex pipiens quinquefasciatus

1970 ◽  
Vol 53 (4) ◽  
pp. 215 ◽  
Author(s):  
M. D. Boston ◽  
R. S. Patterson ◽  
C. S. Lofgren
Keyword(s):  
Culex Pipiens ◽  
Culex Pipiens Quinquefasciatus

scholarly journals Effects of Propoxur Exposure on Insecticidal Susceptibility and Developmental Traits in Culex pipiens quinquefasciatus

Insects ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 288
Author(s):  
Xiaolei Zhang ◽  
Samuel Karungu ◽  
Quanxin Cai ◽  
Zhiming Yuan ◽  
Xiaomin Hu
Keyword(s):  
Culex Pipiens ◽  
Constitutive Expression ◽  
Adult Survivors ◽  
Lethal Concentration ◽  
P450 Monooxygenase ◽  
Resistance Development ◽  
Culex Pipiens Quinquefasciatus ◽  
Rate Of Increase ◽  
Developmental Traits ◽  
Net Reproduction

Propoxur-sel strains of Culex pipiens quinquefasciatus were derived from a lab-bred strain following 16 generations of propoxur exposure under sublethal concentrations of LC25 (lethal concentration of 25%) and LC50 (lethal concentration of 50%), respectively. This resulted in resistance development in F16 with ratios of 8.8× and 6.3×, respectively, compared with F0. The fecundity, longevity, sex ratio (F/M), and hatchability of the propoxur-exposed Cx. quinquefasciatus adult survivors and their offspring were decreased, with no effect on the emergence ratio and pupa survival rate. In addition, the intrinsic rates of increase (r), the net reproduction (R0), and the finite rate of increase (λ) of the Cx. quinquefasciatus offspring generations were also decreased significantly compared to F0. Correspondingly, the mean generation time (T) and the population double time (DT) in propoxur-sels were increased. Enhanced activities of cytochrome P450 monooxygenase and esterase were also observed in propoxur-sels, indicating that a detoxification mechanism might be responsible for resistance development in Cx. quinquefasciatus. Except for the three genes cyp4d42v1, cyp4c52v1, and cyp6aa9 which displayed a coincidence in some degree in different treatments, induction by different doses of propoxur and constitutive expression in different generations of propoxur-sel strains resulted in an inconsistent identification of the P450 genes probably related with resistance.

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