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PubMed1988

Identification of a German cockroach-specific allergen by human IgE and rabbit IgG.

To further study the immunology of insect hypersensitivity, we identified and partially characterized the principal allergens in whole body German cockroach (WBGCR) (Blattella germanica) and compared this extract to whole body antigens prepared from other insects. WBGCR extract was fractionated over a calibrated Sephadex G-200 column; peak allergenic activity was contained in fraction 3 (GCR3), containing components with apparent molecular weights ranging from 12,500 to 75,000 daltons. The antigenicity, allergenicity, and specificity of GCR3 components were tested by using rabbit antisera raised to GCR3 or true armyworm (Pseudaletia unipuncta). Radioimmunoassay, cross-inhibition and immunoblot studies revealed, particularly in the IgE system, that GCR3 contained an allergen with a pI of 6.7 and MW of 36,000 daltons that was unique to WBGCR extracts and not present in other insect species, including true armyworm, caddis fly, lakefly, yellow jacket, or honeybee. This GCR3 component may represent a specific marker for the diagnosis of cockroach hypersensitivity in an insect-sensitive population of individuals.

Allergens↗
PubMed1995

Development of cockroach-allergic guinea pig by simple room air contamination.

Asthma is frequently associated with inhalant sensitivities, particularly allergens of indoor environment. The aim of the study is to determine whether an indoor allergen, cockroach (CRa), can induce guinea pig sensitization without adjuvant or special manipulation. Six regimens were used in sensitizing guinea pigs by CRa aerosols: low daily (C-I), low intermittent (C-II), high intermittent (C-III), maximum intermittent (C-IV), high daily (C-V) and high alternate day (C-VI) doses, and results were compared with that of intraperitoneal sensitization (C-VII). Also studied was a role of CRa in the aerosol ovalbumin (OA) sensitization in comparison with placebo and an adjuvant, Al(OH)3. Reaginic guinea pig antibodies, anti-CRa-IgGla-like (IgGla) and IgE-like (IgE), were measured by passive cutaneous anaphylaxis (PCA). Results show that IgGla was produced only in high-dose aerosol groups, C-V and C-VI, but no IgE in all aerosol groups. The antibody was detected on day 22 (C-V) and day 19 (C-VI) and sustained till day 52 (titers 1:20 to 1:200). The preliminary pulmonary function measurements revealed that the sensitized animals (C-VI) showed a decreased ventilatory function upon CRa challenge. Aerosolized OA sensitization also produced anti-OA-IgGla in high intermittent regimens. In addition, PCA titers (anti-OA-IgGla) in OA-sensitized animals were not influenced by pretreatment with CRa, Al(OH)3, or placebo. Thus, the study indicates that simple aerosolized CRa contamination in a chamber makes guinea pigs cockroach-sensitive and become asthmatic. Yet, CRa does not enhance other allergen sensitization.

Aerosols↗
PubMed2002

Cockroach allergen Bla g 2: structure, function, and implications for allergic sensitization.

Exposure to German cockroach (Blattella germanica) allergens is associated with the development of chronic respiratory diseases, especially asthma. The mechanism by which allergic patients develop specific immunoglobulin E (IgE) responses to environmental allergens is unknown. However, recent reports provided evidence that enzyme activity, especially proteolytic activity, was a major contributor to allergenicity. Bla g 2 is one of the most potent cockroach allergens (prevalence of IgE responses of 60 to 80%) and shows homology to the aspartic proteinase family of enzymes. We investigated whether the allergenicity of Bla g 2 was linked to its putative enzymatic function. A molecular model of Bla g 2, based on the high resolution crystal structures of pepsin and chymosin, showed that the overall three-dimensional structure of Bla g 2 was similar to that of aspartic proteinases with a well-defined binding pocket. However, critical amino acid substitutions in the catalytic triads and in the "flap" region of the molecule suggested that Bla g 2 was inactive and homologous to mammalian pregnancy-associated glycoproteins. This was confirmed experimentally by enzyme assay. The results show dissociation between enzymatic activity and allergenicity for Bla g 2 and suggest that other genetic and environmental factors are important determinants of sensitization.

Amino Acid Sequence↗
PubMed2007

Circadian rhythms in the mating behavior of the cockroach, Leucophaea maderae.

Mating behavior of small populations of virgin males and females of the cockroach Leucophaea maderae were continuously monitored via time-lapse video recording in controlled laboratory conditions. The time of onset of copulation was found to be rhythmic in a light cycle of 12 h light alternated with 12 h of darkness, with the peak of mating behavior occurring near the light to dark transition. This rhythm persisted in constant dim red illumination and constant temperature. In constant conditions, the period of the rhythm was slightly less than 24 h, with a peak of copulation during the late subjective day. These data demonstrated that mating behavior is gated by a circadian clock. When males and females were taken from light cycles that were 12 h out of phase, a bimodal rhythm was observed with one peak in the males' late subjective day and a second peak of equal amplitude in the late subjective day of females. The results indicated that circadian systems in both males and females contribute to the circadian rhythm in copulation. Bilateral section of the optic tracts (OTX) of both males and females abolished the rhythm, but the rhythm persisted when OTX females were paired with intact males or when OTX males were paired with intact females. Furthermore, when OTX males or OTX females were paired with intact animals that were 12 h out of phase, a bimodal rhythm was still observed. These results suggested that the circadian pacemaker in the optic lobes of both male and female cockroaches participates in the control of mating, but that a pacemaker outside the optic lobes is also likely involved. Finally, it was shown that the female's olfactory response (measured by electroantennogram) to components of the male sex pheromone exhibited a circadian rhythm, but the data suggested the peripheral olfactory rhythm is not likely to be involved in the rhythm of mating behavior.

Animals↗
PubMed1990

Circadian rhythms of locomotor activity in cockroach nymphs: free running and entrainment.

The temporal organization of locomotor activity was investigated in nymphs of the cockroach Leucophaea maderae. Approximately 40% of the animals examined between 1 and 50 days of age exhibited a circadian activity rhythm in constant darkness (n = 172) with an average free-running period of 23.7 +/- 0.68 hr. Twelve of 17 animals in which activity was recorded for most or all of the final instar also exhibited periods of rhythmic activity. The rhythms of the nymphs could be entrained by light-dark (LD) cycles with periods of 22, 24, or 26 hr. In contrast, neither maternal influences during embryogenesis nor hatching from the egg was effective in synchronizing the rhythms. Although adult cockroaches can be readily entrained by temperature cycles, in nymphs temperature appeared at best to be a weak zeitgeber. Embryonic exposure to an LD cycle until 6 days prior to egg hatch was effective in synchronizing the activity rhythms of the nymphs, indicating that differentiation of an entrainable pacemaking system occurs prior to hatching.

Aging↗
PubMed1975

Motor innervation within supernumerary legs of cockroaches.

1. Clusters of legs having prothoracic and metathoracic origins were grown from the metathoracic coxa of the cockroach. 2. Or occasionally two, of the three major nerves innervating the cockroach leg. 3. Stimulation of a particular leg nerve (no. 3, 5 or 6) evoked movement at the same joints and in the same directions in a leg having only one nerve as in a normal leg. 4. Stimulation of a particular metathoracic nerve generally produced the same movements in a prothoracic leg transplanted to the metathoracic site as it did in a regenerated or intact metathoracic leg.

Action Potentials↗
PubMed1979

Pharmacological properties of axonal sodium channels in the cockroach Periplaneta americana L. I. Selective block by synthetic saxitoxin.

Voltage-clamp experiments on isolated giant axons of the cockroach Periplaneta americana L. show that chemically synthesized saxitoxin specifically and reversibly blocks the transient inward sodium current without affecting the steady-state outward potassium current. From the concentration depending of sodium current suppression it is concluded that individual sodium channels are blocked by single molecules of synthetic saxitoxin which bind reversibly to part of the channel with a dissociation constant of 3.0 x 10(-9) M. Synthetic saxitoxin blocks sodium channels in cockroach axons at a lower concentration than tetrodotoxin. Sodium channel block by synthetic saxitoxin is more readily reversed than tetrodotoxin-induced block.

Animals↗
PubMed1979

Pharmacological properties of axonal sodium channels in the cockroach Periplaneta americana L. II. Slowing of sodium current turn-off by Condylactis toxin.

Condylactis toxin induces a prolonged falling phase in action potentials recorded from giant axons of the cockroach Periplaneta americana L. A distinct plateau potential can be recorded in the presence of Condylactis toxin at concentrations of 0.5 mg/ml and above. In cockroach axons, voltage-clamp experiments show that Condylactis toxin acts primarily by slowing the sodium current turn-off without affecting either the time-course of the sodium conductance increase or the peak amplitude of the transient sodium current.

Action Potentials↗
PubMed1982

Actions of insect toxin and other toxins derived from the venom of the scorpion Androctonus australis on isolated giant axons of the cockroach (Periplaneta americana).

1. Insect toxin, mammal toxins I and II and crustacean toxin were obtained from the venom of the scorpion Androctonus australis. Their effects on the isolated giant axon of the cockroach Periplaneta americana were investigated by current-clamp and voltage-clamp techniques. 2. In current-clamp conditions, mammal toxins and crustacean toxin (1.3-13 microM) induced a large prolongation of the falling phase of the evoked action potentials. Insect toxin (0.13-3.3 microM) induced a progressive slow depolarization of the membrane potential and repetitive firing of action potentials. No changes in the time-course of the action potential were induced by insect toxin. 3. In voltage-clamp conditions, mammal and crustacean toxins induced a slowing of the turn-off of the transient inward sodium current, with either no change or a small increase in the peak sodium current. Insect toxin by contrast induced an increase in the peak sodium current and a slowing of the sodium current turn-off, this effect being greatest at lower values of the clamped membrane voltage. 4. It is concluded that the repetitive activity induced by insect toxin results from a voltage-dependent modulation of sodium inactivation coupled with an increase in both the resting and active sodium permeabilities of the cockroach axonal membrane.

Action Potentials↗
PubMed1988

Arthropod immune system. V. Activated immunocytes (granulocytes) of the German cockroach, Blattella germanica (L.) (Dictyoptera: Blattellidae) show increased number of microtubules and nuclear pores during immune reaction to foreign tissue.

The German cockroach, Blattella germanica (L.) (Dictyoptera: Blattellidae) has two major immunocytes (blood cells) (granulocytes (GRs) and plasmatocytes). The GRs participate both in encapsulation and phagocytosis of nonself tissue. Structurally, the GRs are flattened and discoid, and contain, among other organelles, microtubules that are arranged in the form of a bundle in their peripheral region in the plane of flattening. If one implants a foreign tissue in the cockroach's abdomen, the GRs become activated and begin to encapsulate the implant by flattening and wrapping around it. The activated GRs show considerable increase in the number of both the microtubules and the nuclear pores of the nuclear envelope. Such structural changes in an activated arthropod immunocyte and their functional significance in its immune reaction against a foreign tissue have not been previously reported. We believe that the large number of microtubules is necessary not only to maintain the flattened nature of the GRs, but also to ensure the formation of an effective capsule against the deforming and shearing forces of the foreign tissue. And to keep up with the rapid assembly of new microtubules during encapsulation, the nucleus apparently triggers the synthesis of tubulin via ribosomes, its nuclear pores serving as channels for molecular transport to and from the nucleus. A structural and functional analogy between GRs and human platelet has also been suggested.

Animals↗
PubMed2002

Deteriorated housing contributes to high cockroach allergen levels in inner-city households.

The high prevalence of childhood asthma in low-income, inner-city populations is not fully understood but has been at least partly attributed to the disproportionate exposures associated with socioeconomic disadvantage. The contribution of indoor allergens to asthma is well documented, but links between socioeconomic disadvantage and indoor allergen levels are not clear. We investigated levels of cockroach allergens (Bla g 2) in a sample of 132 Dominican or African American low-income households with young children in northern Manhattan in New York City (40% were receiving public assistance) to determine whether the distribution of allergens is a function of housing deterioration. Deterioration was measured by the presence and number of physical housing problems (holes in the ceilings and walls, water damage, etc.). More than 50% of the sample had two or more types of housing dilapidation, and 67% of the sample reported cockroach sightings in their homes. Samples of dust were collected from kitchen and bedroom surfaces. We hypothesized that the greater the dilapidation, the higher the allergen levels, independent of income, sociocultural factors, and pest-control methods. In addition, we hypothesized that the homes of families characterized by frequent moves (23.5%) would have higher allergen levels than more stable families. Results showed significant positive associations between housing deterioration and allergen levels in kitchens, after adjusting for income and ethnicity, with independent effects of residential stability (p< 0.05). Bedroom allergen levels were associated with housing instability (p < 0.01) and ethnicity (p< 0.01). Findings demonstrated that indoor household allergen levels are related to degree of household disrepair, after adjusting for individual family attributes, suggesting that social-structural aspects of housing may be appropriate targets for public health interventions designed to reduce allergen exposure.

Adolescent↗
PubMed2005

Association of housing disrepair indicators with cockroach and rodent infestations in a cohort of pregnant Latina women and their children.

Health burdens associated with poor housing and indoor pest infestations are likely to affect young children in particular, who spend most of their time indoors at home. We completed environmental assessments in 644 homes of pregnant Latina women and their children living in the Salinas Valley, California. High residential densities were common, with 39% of homes housing > 1.5 persons per room. Housing disrepair was also common: 58% of homes had peeling paint, 43% had mold, 25% had water damage, and 11% had rotting wood. Evidence of cockroaches and rodents was present in 60% and 32% of homes, respectively. Compared with representative national survey data from the U.S. Department of Housing and Urban Development, homes in our sample were more likely to have rodents, peeling paint, leaks under sinks, and much higher residential densities. The odds of rodent infestations in homes increased in the presence of peeling paint [odds ratio (OR) 2.1; 95% confidence interval (CI), 1.5-3.1], water damage (OR 1.9; 95% CI, 1.2-2.7), and mold (OR 1.5; 95% CI, 1.0-2.1). The odds of cockroach infestation increased in the presence of peeling paint (OR 3.8; 95% CI, 2.7-5.6), water damage (OR 1.9; 95% CI, 1.2-2.9), or high residential density (OR 2.1; 95% CI, 1.2-3.8). Homes that were less clean than average were more prone to both types of infestations. Pesticides were stored or used in 51% of households, partly to control roach and rodent infestations. These data indicate that adverse housing conditions are common in this community and increase the likelihood of pest infestations and home pesticide use. Interventions to improve housing and promote children's health and safety in this population are needed.

Adult↗
PubMed2005

Pigment-dispersing factor and GABA synchronize cells of the isolated circadian clock of the cockroach Leucophaea maderae.

Pigment-dispersing factor-immunoreactive circadian pacemaker cells, which arborize in the accessory medulla, control circadian locomotor activity rhythms in Drosophila as well as in the cockroach Leucophaea maderae via unknown mechanisms. Here, we show that circadian pacemaker candidates of the accessory medulla of the cockroach produce regular interspike intervals. Therefore, the membrane potential of the cells oscillates with ultradian periods. Most or all oscillating cells within the accessory medulla are coupled via synaptic and nonsynaptic mechanisms, forming different assemblies. The cells within an assembly share the same ultradian period (interspike interval) and the same phase (timing of spikes), whereas cells between assemblies differ in phase. Apparently, the majority of these assemblies are formed by inhibitory GABAergic synaptic interactions. Application of pigment-dispersing factor phase locked and thereby synchronized different assemblies. The data suggest that pigment-dispersing factor inhibits GABAergic interneurons, resulting in disinhibition and phase locking of their postsynaptic cells, which previously belonged to different assemblies. Our data suggest that phase control of action potential oscillations in the ultradian range is a main task of the circadian pacemaker network. We hypothesize that neuropeptide-dependent phase control is used to gate circadian outputs to locomotor control centers.

Action Potentials↗
PubMedDate not supplied

Observation on the host parasitoid interaction between Periplaneta americana, the American cockroach and Tetrastichus hagenowii, an oothecal parasitoid.

Investigations were carried out on the host parasitoid interaction between Periplaneta americana, the American cockroach and Tetrastichus hagenowii, an oothecal parasitoid. This gregarious female parasitoid infected and or oviposited in only one host and caused 100% mortality of the infected host. However, increase in parasitoid density decreased the progeny production and influenced the sex ratio. The progenies produced were male biased. When host preference was tested by offering oothecae of different species of cockroaches. T. hagenowii showed a predilection towards the oothecae of P. americana, suggesting its host specificity.

Animals↗
PubMed1985

PHI-like immunoreactivity in the nervous system of the cockroach (insect) and Aplysia (mollusc) with special reference to its relationship to VIP-like immunoreactivity.

Studies in mammals have indicated that PHI (peptide histidine isoleucine) and VIP (vasoactive intestinal polypeptide) share a prepropeptide, and that both peptides are contained in the same neurons. The present study proposes that this relationship may not hold true in protostomian invertebrates. In the nervous system of the cockroach (Insecta, Arthropoda) and Aplysia (Gastropoda, Mollusca) distribution of PHI and VIP was examined by immunocytochemistry. In both animals neurons containing PHI-like immunoreactivity were numerously found and only a small part of them in the cockroach contained VIP-like immunoreactivity. These findings suggest that in these invertebrates, PHI may play a more important regulatory role than VIP. Possible reasons for the difference in the distribution of immunoreactivities for PHI and VIP are discussed.

Animals↗
PubMed2005

Phylogenetic analyses of fat body endosymbionts reveal differences in invasion times of blaberid wood-feeding cockroaches (Blaberidae: Panesthiinae) into the Japanese archipelago.

Cockroaches have endosymbiotic bacteria in their fat bodies. Recent molecular phylogenetic analyses on both hosts and endosymbionts have revealed that co-evolution has occurred throughout the history of cockroaches and termites. Co-cladogenesis was also shown among closely related taxa (woodroach genus Cryptocercus; Cryptocercidae), and thus endosymbiont data are likely to be useful for biogeographical analyses. To test the possibility of co-cladogenesis among inter-and intraspecific taxa, as well as the utility of endosymbiont data for inferring biogeographical scenarios, we analyzed rRNA genes of endosymbionts of Japanese and Taiwanese Panesthiinae (Salganea and Panesthia; Blaberidae), on which phylogenetic analyses previously had been performed based on the mitochondrial genes. Statistical analyses on the topologies inferred from both endosymbiont and host mitochondria genes showed that co-cladogenesis has occurred. The endosymbiont sequences examined appear to have evolved in a clock-like manner, and their rate of evolution based on the host fossil data showed a major difference in the time of invasion of the two Japanese genera, that is congruent with the recent analyses of their mitochondrial genes.

Animals↗
PubMed1980

Conversion of [U-14C] glucose to lipid in the American cockroach, Periplaneta americana L.

The incorporation of D-[U-14C] glucose into fat body acylglycerols was studied in fed and starved adult cockroaches, Periplaneta americana. About 7-10% of injected glucose is incorporated into the triacylglycerol component of fat body within three hours of injection. The capacity for conversion of glucose to triacylglycerol is greater in fed than starved Insects and the differences in lipogenic capacity of fat body from fed and starved cockroaches are retained in vitro. Incubation of fat body in the presence of haemolymph enhances the lipogenic capacity of fat body.

Adipose Tissue↗
PubMed2006

Field trial on the control effect of fipronil bait against German cockroaches.

A field trial on the control effect of fipronil poison bait against German cockroaches (Blatella germanica) was carried out at different restaurant types in Sinchon, Seoul, Republic of Korea. Monitoring was performed applying food baited traps for 2 days per week. Reduction rates of German cockroaches by applying fipronil baits were 90.9% at Korean restaurants, 96.4% at Chinese restaurants, and 89.4% in beer hall kitchens after 4 weeks of the treatment. Overall average of the reduction rate was 93.9%. As the natural reduction rate at untreated restaurants was 11.5% after 4 weeks, a correction of the average reduction rate by applying the Abbot formula was 93.1%.

Animals↗