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PubMed1991

Distribution of Oriental and German cockroaches, Blatta orientalis and Blattella germanica (Dictyoptera), in the United Kingdom.

Results are presented of a survey carried out by Rentokil Ltd on the distribution of the Oriental cockroach Blatta orientalis L. and the German cockroach Blattella germanica L. in the United Kingdom. The known ranges of both species are increased considerably by the findings of the survey, with several new vice-county records for Scotland (including the Western Isles), England and Wales. The frequency at which Blatta orientalis was observed in outdoor habitats may indicate that this species sometimes spreads to new areas without human assistance.

Animals↗
PubMed1992

Synergism of chlorpyrifos against the German cockroach, Blattella germanica.

Of fifteen compounds tested as synergists for chlorpyrifos against susceptible and resistant strains of Blattella germanica, the German cockroach, eleven were active against the resistant strain but only seven were synergistic against the susceptible strain. Overall, the most effective synergist was S,S,S-tributyl phosphorotrithioate (DEF) followed by phenyl saligenin cyclic phosphonate (PSCP) and two substituted N,N-dimethylcarbamates: SK-102 and SK-37. The most effective synergist for overcoming chlorpyrifos resistance was SK-37 which reduced the resistance ratio by 3.2-fold. Four other synergists which reduced chlorpyrifos resistance, in order of their effectiveness, were: SK-102 > PSCP > DEF > tridiphane. The potential usefulness of these synergists for German cockroach control is discussed.

Animals↗
PubMed1994

Cat (Fel d I), dog (Can f I), and cockroach allergens in homes of asthmatic children from three climatic zones in Sweden.

We have investigated the levels of cat (Fel d I), dog (Can f I), and cockroach (Per a I) allergens in dust from bedrooms, living rooms, kitchens, and bathrooms from 123 homes of asthmatic children in three zones of Sweden with varying climates. Absolute indoor humidity (AIH), relative humidity (RH), rate of ventilation in air changes per hour (ach), and number of airborne particles were also measured. Fel d I, Can f I, and Per a I allergen contents were determined by mab ELISA, and the levels were related to various environmental factors. The major cat allergen, Fel d I, was detected in all homes, and the concentrations varied between 16 ng and 28,000 ng/g fine dust. The dog allergen, Can f I, was detected in 85% of the homes, and the levels varied from 60 ng to 866,000 ng/g dust. Cockroach allergen was detected in only one home (40 ng/g). Fel d I and Can f I allergens were equally distributed geographically. Dust from living rooms contained significantly higher (P < 0.05) concentrations of both Fel d I and Can f I allergens than dust from bedrooms, kitchens, and bathrooms. The levels tended to be higher in homes with poor ventilation (< 0.5 ach) and in homes with wall-to-wall carpets. Significantly higher (P < 0.01) numbers of airborne particles were found in homes with high humidity (i.e., AIH > or = 7 g/kg or RH > or = 45%).(ABSTRACT TRUNCATED AT 250 WORDS)

Air Conditioning↗
PubMed1998

Guanine, mite, and cockroach allergens in Costa Rican homes.

Previous studies of schoolchildren in Costa Rica have shown an asthma prevalence of 23% and a high level of sensitization, particularly to mite allergens. As a continuation of these studies, some 400 dust samples were collected from various places in Costa Rica, and parts of these were analyzed for specific mite and cockroach allergens, as well as for the number of mites and amount of guanine. Guanine was quantified by a diazo, as well as an HPLC method, which were found to be highly correlated. The concentrations of guanine by the diazo method, Der p 1, Der f 1, and the number of mites were higher in bed dust than in bedroom floor dust, and it was possible to quantify mite allergens and guanine in almost all bed-dust samples. The mean levels were 2-3 times higher than the proposed risk level for elicitation of symptoms in mite-sensitive asthmatics. Bed and bedroom floor dust contained more guanine and mite allergen in humid (> 2000 mm rain) than in drier places (P < 0.05), but the number of mites in bed and bedroom floor dust was higher in less humid places (P = 0.01). The guanine content in bedroom floor dust was higher in areas with a temperate climate than in areas with a warmer climate (P < 0.001, Bartlett's chi square [BCS]), as was the number of mites (P < 0.01, Kruskal-Wallis [KW], 0.04, BCS) and the Der p 1 concentration (P = 0.01, BCS; P = 0.02, KW). The Der f 1 concentration in bedroom floor dust was higher in a warmer than in a temperate climate (P < 0.001, BCS). More guanine and mites were found in urban than in rural bed dust (P = 0.03, KW). Dust samples from the metropolitan area (temperate climate) of Costa Rica contained higher levels of guanine (P < 0.01) and Der p 1 (P = 0.07) than the coastal areas, but very little Der f 1. In these samples, guanine and Der p 1 allergen were closely related, and 2 micrograms of the allergen was equivalent to 0.49 mg of guanine. Two-thirds of bed and floor samples collected on cotton filters contained Bla g 2 allergen at mean levels of 1.6 and 2.1 units/g dust, respectively. Cockroach allergen was, however, absent in all bed samples from the metropolitan area, but did occur in very high concentrations in the coastal bed dust samples collected with tighter polyester filters. In conclusion, the concentration of guanine and Der p 1 was very high in the bed dust of Costa Rican homes. Some factors, such as humidity, small houses for large families, and type of bedding, probably favored the heavy mite infestation, which is probably related to the widespread occurrence of bronchial asthma in this country.

Allergens↗
PubMed1980

Cockroach collagen: isolation, biochemical and biophysical characterization.

Collagen fibrils from the mesenteric connective sheath of the adult cockroach Periplaneta americana were extracted by enzymatic digestion with pepsin and were purified. Chromatographic studies and sodium dodecylsulfate electrophoresis revealed the presence of a single chain. It was demonstrated that the structure of this collagen could be represented by the formula (alpha)3. The amino acid composition is typical of collagens (one-third glycine, and a high imino acid content) and similar to that of type II. The carbohydrate content was high (8.8%), and the cyanogen bromide pattern was different from that of known collagens. The chains were linked by the stable intermolecular bond dihydroxylysinonorleucine. The banding patterns of the segment-long-spacing crystallites and of the reconstituted fibrils were similar to type I collagen. The molecular weight (Mr 280,000) and length (285 nm) were typical, but the denaturation temperature was high (38.5 degrees C). It was concluded that cockroach mesenteric collagen showed the characteristic features of invertebrate mesodermal collagens, except that of the thermal stability of the triple-helical structure.

Amino Acids↗
PubMed1995

Comparison of the allatostatin neuropeptide precursors in the distantly related cockroaches Periplaneta americana and Diploptera punctata.

Allatostatins are a family of insect neuropeptides that inhibit juvenile hormone biosynthesis by the corpora allata. We have characterized cDNA and genomic DNA sequences that specify a preproallatostatin precursor in the oviparous cockroach Periplaneta americana. Comparison of this precursor with that previously described [Donly, B. C., Ding, Q., Tobe, S. S. & Bendena, W. G. (1993) Proc. Natl Acad. Sci. USA 90, 8807-8811] for the viviparous cockroach Diploptera punctata revealed several common features. First, the precursors are remarkably similar in size and the organization of the peptides within the precursor is conserved. The separation of the peptides into groups by acidic domains within the precursor has been maintained. The P. americana precursor contains 14 allatostatin-like peptides that contain the core C-terminal sequence (Tyr/Phe)-Xaa-Phe-Gly-(Leu/Ile)-NH2, as compared to the D. punctata precursor, which contains 13. Five of the peptides are perfectly conserved between the two species. The remainder, with one exception, contain amino acid substitutions in the N-terminal address portion of the peptide. Several features of expression are also similar between these two species. In both, a single copy gene specifies a large allatostatin transcript of 5.0 kb in P. americana and 9.2 kb in D. punctata. In P. americana, allatostatin transcripts appear to be produced by numerous cells in different regions of the brain.

Amino Acid Sequence↗
PubMed1977

Sexual behavior in the cockroach genera Periplaneta and Blatta. III. Aggression and sexual behavior.

Relationships between aggression and sexual behavior were examined in 6 cockroach species (genera Periplaneta and Blatta) in a descriptive manner. Aggressive encounters were classified according to intensity level. The behaviors themselves were scrutinized for differences according to varying contexts such as food and water deprivation and sexual situations. Sexual and species differences in aggressive behaviors were analyzed. Sexual encounters in cockroaches are considered as conflict situations in which many of the sexual behaviors of male male serve to neutralize aggressive behaviors of the female. Major adaptations include a male pheromene, tergal glands and defensive manoeuvering with body and legs.

Aggression↗
PubMedDate not supplied

Evolution of a novel function: nutritive milk in the viviparous cockroach, Diploptera punctata.

Cockroach species show different degrees of maternal contribution to the developing offspring. In this study, we identify a multigene family that encodes water-soluble proteins that are a major component of nutritive "Milk" in the cockroach, Diploptera punctata. This gene family is associated with the evolution of a new trait, viviparity, in which the offspring receive nutrition during the gestation period. Twenty-five distinct Milk complementary DNAs were cloned and partially characterized. These complementary DNAs encode 22 distinct Milk peptides, each of length 171 amino acids, including a 16-amino acid signal peptide sequence. Southern blot analysis confirms the presence of multiple copies of Milk genes in D. punctata. Northern analysis indicates tissue- and stage-specific Milk gene expression. Examination of the deduced amino acid sequences identifies the presence of structurally conserved regions diagnostic of the lipocalin protein family. The shared exon/intron structure of one of the Milk loci with lipocalin genes further supports a close evolutionary relationship between these sequences.

Amino Acid Sequence↗
PubMed1998

Responses of cockroach antennal lobe projection neurons to pulsatile olfactory stimuli.

Behavioral evidence indicates that insects preferentially orient toward pulses of odorants as they occur downwind from a point source. Our recent results have shown that cockroach olfactory receptor neurons are able to reliably resolve 10-Hz pulses of the general "green' odorant 1-hexanol, but it is unknown to what extent the central olfactory pathway is able to resolve temporal aspects of a general odor stimulus. In the present study, temporal response characteristics were measured in antennal lobe projection neurons of female American cockroaches, Periplaneta americana in response to series of short odor pulses (2.5-20 Hz). Odor pulses were delivered to olfactory sensilla in a moving airstream controlled by electromagnetic valves and quantified by replacing the odorant with oil smoke and measuring the concentration of smoke passing through a light beam. The responses of projection neurons were recorded with an intracellular microelectrode placed in the projection neuron cell body. A variety of time courses of responses were recorded. Response patterns were consistent among identical stimuli within a neuron and varied among neurons. Some neurons increased spike frequency with stimulus onset while others decreased spike frequency. The latency to the change in spike frequency and the duration of the response also varied among neurons. Regardless of the temporal characteristics of the responses, nearly all projection neurons were able to resolve pulses of 1-hexanol presented at 5 Hz and some could resolve 10-Hz pulses. Thus, responses of antennal lobe projection neurons can reflect fine structures of non-uniform distributions of general odorants in a turbulent odor plume. In addition, the variety of temporal response characteristics to identical stimuli suggests that odor quality is coded by a temporal code expressed across a population of projection neurons.

Animal Communication↗
PubMed1981

Effects of localized low-temperature pulses on the cockroach circadian pacemaker.

The hypothesis that the circadian pacemaker that controls the activity rhythm in the cockroach, Leucophaea maderae, is composed of mutually coupled optic lobe oscillators was investigated using localized low-temperature pulses. Following section of one optic tract cooling the intact optic lobe for 6 h (7.5 degrees C) beginning at activity onset consistently caused a phase delay of several hours. Cooling the neurally isolated lobe had little or no effect. The results suggested the low-temperature phase delays the rhythm via a phase shift in an oscillator in the optic lobe. To determine if optic lobe oscillators were coupled, low-temperature pulses were given to one optic lobe of intact animals. If the treated lobe was isolated by optic tract section 4 days after the pulse, the rhythm (driven by the untreated lobe) was delayed; but if the tract was cut 0.5 h after the pulse the phase shift was prevented. The interaction between the optic lobes in intact animals was also found to reduce the delay caused by a low-temperature pulse. These results suggest the cockroach circadian pacemaker is composed of two mutually coupled optic lobe oscillators.

Animals↗
PubMed2005

Gap junctions between accessory medulla neurons appear to synchronize circadian clock cells of the cockroach Leucophaea maderae.

The temporal organization of physiological and behavioral states is controlled by circadian clocks in apparently all eukaryotic organisms. In the cockroach Leucophaea maderae lesion and transplantation studies located the circadian pacemaker in the accessory medulla (AMe). The AMe is densely innervated by gamma-aminobutyric acid (GABA)-immunoreactive and peptidergic neurons, among them the pigment-dispersing factor immunoreactive circadian pacemaker candidates. The large majority of cells of the cockroach AMe spike regularly and synchronously in the gamma frequency range of 25-70 Hz as a result of synaptic and nonsynaptic coupling. Although GABAergic coupling forms assemblies of phase-locked cells, in the absence of synaptic release the cells remain synchronized but fire now at a stable phase difference. To determine whether these coupling mechanisms of AMe neurons, which are independent of synaptic release, are based on electrical synapses between the circadian pacemaker cells the gap-junction blockers halothane, octanol, and carbenoxolone were used in the presence and absence of synaptic transmission. Here, we show that different populations of AMe neurons appear to be coupled by gap junctions to maintain synchrony at a stable phase difference. This synchronization by gap junctions is a prerequisite to phase-locked assembly formation by synaptic interactions and to synchronous gamma-type action potential oscillations within the circadian clock.

Action Potentials↗
PubMed1988

Connectivity pattern of the cercal-to-giant interneuron system of the American cockroach.

1. The pattern of connectivity between identified cercal afferents and the three largest giant interneurons (GIs 1, 2, and 3) of the American cockroach was investigated by intracellular methods. These three GIs all have different directional response sensitivities and appear to be especially important in initiating the short latency escape behavior of the American cockroach. 2. One of the interneurons, GI 1 responds to wind from all four quadrants of space about the animal. However, it clearly shows a greater ipsilateral versus contralateral (relative to the GI's axon within the nerve cord) wind sensitivity. In contrast, the directional sensitivity of GI 2 is more nearly bilaterally symmetrical. Both of these interneurons receive excitatory synaptic input from the sensory cells of the nine most prominent columns (a, d, g, f, h, i, k, l, and m) of filiform hairs of the ipsilateral cercus. 3. The nine ipsilateral inputs all made roughly equivalent strength excitatory connections with GI 1. The connectivity pattern to GI 2 was the same as that to GI 1 except that the connection strength for two of the nine columns, h and i, was substantially stronger to GI 2 than to GI 1. The remaining seven sensory columns all make equivalent strength connection with GI 2. 4. Only select columns of contralateral sensory cells made synaptic connection with GIs 1 and 2. All detectable connections produced subthreshold depolarizations. 5. The response curve of GI 3 is more sharply restricted in space than that of either GI 1 or 2 and this interneuron only responds to wind stimuli originating from in front of the animal. GI 3 received excitatory synaptic input only from ipsilateral columns d, f, g, i, and k, all of which have their best excitatory directions well within the boundaries of the response curve of GI 3. Columns a and l with best excitatory directions near the edges of the response curve of GI 3 made no detectable connection. The remaining two columns (h and m) with best excitatory directions well outside the boundaries of the response curve of GI 3 provided inhibitory input. 6. GI 3 received synaptic input from contralateral columns d, f, g, h, i, k, and m.(ABSTRACT TRUNCATED AT 400 WORDS)

Afferent Pathways↗
PubMed1997

Electrical properties of a cockroach motor neuron soma depend on different characteristics of individual Ca components.

Electrical properties of a cockroach motor neuron soma depend on different characteristics of individual Ca components. J. Neurophysiol. 78: 2455-2466, 1997. The "fast" coxal depressor motor neuron (Df) of the cockroach is among the most extensively studied of insect neurons. It has been shown that the cell body of this neuron can exhibit active electrical properties, which may change over time or with chemical modulation. To further understand these electrical events and their modulation, inward currents in Df have been characterized under conditions in which outward currents have been suppressed. The inward current activated at potentials positive to -60 mV and peaked between -10 and 0 mV when measured in barium saline and between 0 and +10 mV when measured in calcium saline. The inward current was insensitive to Ni2+ (100 mu M) but reduced by verapamil (50 mu M) and abolished by Cd2+ (1 mM). Two components of ICa were identified by their sensitivity to either 50 mu M nifedipine or micromolar Cd2+. The nifedipine-sensitive component activated positive to -60 mV and peaked between -10 and 0 mV, whereas the Cd2+-sensitive component activated positive to -40 mV and peaked between +10 and +20 mV. Immediately after dissection, depolarization of Df evoked plateau potentials, whereas 1-4 h after dissection, depolarization evoked action potentials. The plateau potentials were insensitive to 100 mu M Cd2+ but blocked by 50 mu M nifedipine, whereas the spikes required a combination of nifedipine (50 mu M) and Cd2+ (100 mu M) for complete suppression, indicating that only one component of ICa contributes to the plateau potential, whereas both components contribute to action potentials. Currents measured in calcium saline decayed faster than currents measured in barium saline. The inactivation characteristics were investigated with the use of double-pulse voltage-clamp experiments. ICa showed a greater degree of inactivation and slower recovery from inactivation than did IBa. Current decay and the extent of inactivation were reduced after injection of the calcium-chelator 1,2-bis(2-aminophenoxy)ethane-N,N, N',N'-tetraacetic acid (BAPTA). This suggests that the calcium current of this neuron displays calcium-dependent inactivation. An additional mechanism, most probably voltage-dependent inactivation, also occurs because IBa, even in neurons injected with BAPTA, displayed some inactivation. The inactivation characteristics may be important in determining activity displayed by Df. Indirect evidence suggests that intracellular calcium is high immediately after dissection. At this time, the calcium current may therefore be reduced due to calcium-dependent inactivation. This may, at least partly, explain why the cell does not spike shortly after dissection.

Animals↗
PubMed1997

Independent coding of wind direction in cockroach giant interneurons.

Independent coding of wind direction in cockroach giant interneurons. J. Neurophysiol. 78: 2655-2661, 1997. In this study we examined the possible role of cell-to-cell interactions in the localization processing of a wind stimulus by the cockroach cercal system. Such sensory processing is performed primarily by pairs of giant interneurons (GIs), a group of highly directional cells. We have studied possible interactions among these GIs by comparing the wind sensitivity of a given GI before and after removing another GI with the use of photoablation. Testing various combinations of GI pairs did not reveal any suprathreshold interactions. This was true for all unilateral GI pairs on the left or right side as well as all the bilateral GI pairs (left and right homologues). Those experiments in which we were able to measure synaptic activity did not reveal subthreshold interactions between the GIs either. We conclude that the GIs code independently for a given wind direction without local GI-GI interactions. We discuss the possible implications of the absence of local interactions on information transfer in the first station of the escape circuit.

Abdomen↗
PubMed1999

Contribution of potassium conductances to a time-dependent transition in electrical properties of a cockroach motoneuron soma.

Contribution of potassium conductances to a time-dependent transition in electrical properties of a cockroach motoneuron soma. The cell body of the cockroach (Periplaneta americana) fast coxal depressor motoneuron (Df) displays a time-dependent change in excitability. Immediately after dissection, depolarization evokes plateau potentials, but after several hours all-or-none action potentials are evoked. Because K channel blockers have been shown to produce a similar transition in electrical properties, we have used current-clamp, voltage-clamp and action-potential-clamp recording to elucidate the contribution of different classes of K channel to the transition in electrical activity of the neuron. Apamin had no detectable effect on the neuron, but charybdotoxin (ChTX) caused a rapid transition from plateau potentials to spikes in the somatic response of Df to depolarization. In neurons that already produced spikes when depolarized, ChTX increased spike amplitude but did not increase their duration nor decrease the amplitude of their afterhyperpolarization. 4-Aminopyridine (4-AP) (which selectively blocks transient K currents) did not cause a transition from plateau potentials to spikes but did enhance oscillations superimposed on plateau potentials. When applied to neurons that already generated spikes when depolarized, 4-AP could augment spike amplitude, decrease the latency to the first spike, and prolong the afterhyperpolarization. Evidence suggests that the time-dependent transition in electrical properties of this motoneuron soma may result, at least in part, from a fall in calcium-dependent potassium current (IK,Ca), consequent on a gradual reduction in [Ca2+ ]i. Voltage-clamp experiments demonstrated directly that outward K currents in this neuron do fall with a time course that could be significant in the transition of electrical properties. Voltage-clamp experiments also confirmed the ineffectiveness of apamin and showed that ChTX blocked most of IK,Ca. Application of Cd2+ (0.5 mM), however, caused a small additional suppression in outward current. Calcium-insensitive outward currents could be divided into transient (4-AP-sensitive) and sustained components. The action-potential-clamp technique revealed that the ChTX-sensitive current underwent sufficient activation during the depolarizing phase of plateau potentials to enable it to shunt inward conductances. Although the ChTX-sensitive conductance apparently makes little contribution to spike repolarization, the ChTX-resistant IK,Ca does make a significant contribution to this phase of the action potential. The 4-AP-sensitive current began to develop during the rising phase of both action potentials and plateau potentials but had little effect on the electrical activity of the neuron, probably because of its relatively small amplitude.

4-Aminopyridine↗
PubMed1999

omega-AgaIVA-sensitive (P/Q-type) and -resistant (R-type) high-voltage-activated Ba(2+) currents in embryonic cockroach brain neurons.

By means of the whole cell patch-clamp technique, the biophysical and pharmacological properties of voltage-dependent Ba(2+) currents (I(Ba)) were characterized in embryonic cockroach brain neurons in primary culture. I(Ba) was characterized by a threshold of approximately -30 mV, a maximum at approximately 0 mV, and a reversal potential near +40 mV. Varying the holding potential from -100 to -40 mV did not modify these properties. The steady-state, voltage-dependent activation and inactivation properties of the current were determined by fitting the corresponding curves with the Boltzmann equation and yielded V(0.5) of -10 +/- 2 (SE) mV and -30 +/- 1 mV, respectively. I(Ba) was insensitive to the dihydropyridine (DHP) agonist BayK8644 (1 microM) and antagonist isradipine (10 microM) but was efficiently and reversibly blocked by the phenylalkylamine verapamil in a dose-dependent manner (IC(50) = 170 microM). The toxin omega-CgTxGVIA (1 microM) had no significant effect on I(Ba). Micromolar doses of omega-CmTxMVIIC were needed to reduce the current amplitude significantly, and the effect was slow. At 1 microM, 38% of the peak current was blocked after 1 h. In contrast, I(Ba) was potently and irreversibly blocked by nanomolar concentrations of omega-AgaTxIVA in approximately 81% of the neurons. Approximately 20% of the current was unaffected after treatment of the neurons with high concentrations of the toxin (0. 4-1 microM). The steady-state dose-response relationship was fitted with a Hill equation and yielded an IC(50) of 17 nM and a Hill coefficient (n) of 0.6. A better fit was obtained with a combination of two Hill equations corresponding to specific (IC(50) = 9 nM; n = 1) and nonspecific (IC(50) = 900 nM; n = 1) omega-AgaTxIVA-sensitive components. In the remaining 19% of the neurons, concentrations >/=100 nM omega-AgaTxIVA had no visible effect on I(Ba). On the basis of these results, it is concluded that embryonic cockroach brain neurons in primary culture express at least two types of voltage-dependent, high-voltage-activated (HVA) calcium channels: a specific omega-AgaTxIVA-sensitive component and DHP-, omega-CgTxGVIA-, and omega-AgaTxIVA-resistant component related respectively to the P/Q- and R-type voltage-dependent calcium channels.

Animals↗
PubMed2000

Multi-joint coordination during walking and foothold searching in the Blaberus cockroach. I. Kinematics and electromyograms.

Cockroaches were induced to walk or search for a foothold while they were tethered above a glass plate made slick with microtome oil. We combined kinematic analysis of leg joint movements with electromyographic (EMG) recordings from leg extensor muscles during tethered walking and searching to characterize these behaviors. The tethered preparation provides technical advantages for multi-joint kinematic and neural analysis. However, the behavioral relevance of the tethered preparation is an important issue. To address this issue, we evaluated the effects of tethering the animals by comparing kinematic parameters of tethered walking with similar data collected previously from cockroaches walking freely on a treadmill at the same speeds. No significant differences between tethered and treadmill walking were found for most joint kinematic parameters. In contrast, comparison of tethered walking and searching showed that the two behaviors can be distinguished by analysis of kinematics and electrical data. We combined analysis of joint kinematics and electromyograms to examine the change in multi-joint coordination during walking and searching. During searching, middle leg joints extended during swing rather than stance (i.e., walking) and the coordination of movements and extensor motor neuron activity at the coxa-trochanteral and femur tibia joints differed significantly during walking and searching. We also found that the pattern of myographic activity in the middle leg during searching was similar to that in the front legs during walking.

Animals↗