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PubMed1992

Vasopressin-immunoreactive neurons and neurohemal systems in cockroaches and mantids.

Vasopressin-like neuropeptides of insects are of special interest because of their possible function as hormones and neuromodulators. Therefore, this study was undertaken by using whole-mount immunofluorescent staining by two antisera that recognize different types of vasopressin-like immunoreactive groups of neurons in the cockroaches Periplaneta americana, Leucophaea maderae, Nauphoeta cinerea, Diploptera punctata, and Blaberus discoidalis and in the mantids Litaneuria minor and Tenodera aridifolia sinensis. Using an antiserum to Arg/vasopressin, only two cells, the paired ventral paramedian (PVP) neurons, were immunostained in the central nervous system (CNS) of the cockroaches. These cells are located in the subesophageal ganglion, project throughout the CNS, and appear to be neurosecretory. Their varicose collaterals extend into the dorsal (motor) neuropil of the segmental ganglia, and this neuropil may be the principal site of the release of their neurosecretion. The PVP neurons were also stained by an antiserum to Lys/vasopressin; in addition, this antiserum stained several other groups of neurons, most of which appeared to be neurosecretory. Two pairs of Lys/vasopressin-immunoreactive cells are similar to the PVP neurons in that they are located in the subesophageal ganglion, extend through the ventral nerve cord, have collaterals in the dorsal neuropil of the segmental ganglia, and appear to be neurosecretory within the CNS. In addition, midventral and anteroventral clusters of Lys/vasopressin-immunoreactive neurosecretory neurons in the subesophageal ganglion project neurohemal release sites on the corpora allata. Other types of Lys/vasopressin-immunoreactive neurons include median and lateral neurosecretory cells of the protocerebrum and neurosecretory cells in the tritocerebrum, all of which project to the corpora cardiaca. In the abdominal ganglia there are posterolateral clusters of Lys/vasopressin neurosecretory neurons, and these cells extend to neurohemal release sites on the transverse and lateral cardiac nerves. In mantids the anti-Arg/vasopressin and anti-Lys/vasopressin antisera stained most of the same groups of neurons that these antisera recognized in cockroaches. The results of this study suggest that there are two or more vasopressin-like peptides in cockroaches and mantids and that these peptides may be released either as hormones in the blood or as neurosecretions within the CNS. Their function(s) in these insects remains to be determined.

Animals↗
PubMed2003

Wasp venom blocks central cholinergic synapses to induce transient paralysis in cockroach prey.

The parasitoid wasp Ampulex compressa induces a set of unique behavioral effects upon stinging its prey, the cockroach. It stings into the first thoracic segment inducing 2 to 3 min of transient flaccid paralysis of the front legs. This facilitates a second sting in the cockroach's head that induces 30 min of excessive grooming followed by a 2 to 5-week long lethargic state. In the present study, we examine the immediate effect of the first sting, which is a transient paralysis of the front legs. Using radiolabeled wasps, we demonstrate that the wasp injects its venom directly into the cockroach's first thoracic ganglion. The artificial injection of milked venom into a thoracic ganglion abolishes spontaneous and evoked responses of the motoneurons associated with leg movements. To investigate the physiological mechanism of action of the venom, we injected venom into the last abdominal ganglion of the cockroach, which houses a well-characterized cholinergic synapse. Injected venom abolishes both sensory-evoked and agonist-evoked postsynaptic potentials recorded in the postsynaptic neuron for 2 to 3 min without affecting action potential propagation. Thus, the venom blocking effect has a postsynaptic component that follows the same time course as the transient paralysis induced by the thoracic sting. Finally, injection of a nicotinic antagonist in the front thoracic ganglion induces paralysis of the front legs. We conclude that the transient paralytic effect of the thoracic sting can be mainly accounted for by the presence of a venom active component that induces a postsynaptic block of central cholinergic synaptic transmission.

Action Potentials↗
PubMed1999

Molecular phylogeny and geographic distribution of wood-feeding cockroaches in East Asian Islands.

Molecular phylogenetic relationships of the wood-feeding cockroach genera Salganea and Panesthia (Blaberidae; Panesthiinae) in East Asian Islands (Ryukyu archipelago and Taiwan Island) were analyzed based on the DNA sequence of the complete mitochondrial cytochrome oxidase II gene. Unweighted parsimony analysis resulted in high bootstrap support for relationships within Panesthia taxa; however, some nodes were unresolved between members of Salganea. Comparison of the number of transitions and transversions with genetic distance at each codon position suggested that saturation of third-codon substitutions has occurred between certain pairs of taxa. Consequently, differential weighting of substitutions at these sites was performed, which resulted in a substantial increase in resolution of Salganea relationships. The inferred phylogenies for both genera displayed good correspondence to the geographical locations of populations but however did not agree with previous subspecies designations based on morphological characters. It appears that both cockroach genera invaded the Ryukyu archipelago from the Taiwan region via a land-bridge present in the Miocene period. Invasion of the main islands of Japan by these cockroaches most likely occurred before the formation of the Tokara Tectonic Strait. Our study suggests that several barriers to gene flow have arisen and persisted over the past approximately 10 million years, which have caused segregation and vicariant speciation of the cockroach taxa of this region.

Animals↗
PubMed1991

Pigment-dispersing hormone-immunoreactive neurons and their relation to serotonergic neurons in the blowfly and cockroach visual system.

The pigment-dispersing hormone (PDH) family of neuropeptides comprises a series of closely related octadecapeptides, isolated from different species of crustaceans and insects, which can be demonstrated immunocytochemically in neurons in the central nervous system and optic lobes of some representatives of these groups (Rao and Riehm 1989). In this investigation we have extended these immunocytochemical studies to include the blowfly Phormia terraenovae and the cockroach Leucophaea maderae. In the former species tissue extracts were also tested in a bioassay: extracts of blowfly brains exhibited PDH-like biological activity, causing melanophore pigment dispersion in destalked (eyestalkless) specimens of the fiddler crab Uca pugilator. using standard immunocytochemical techniques, we could demonstrate a small number of pigment-dispersing hormone-immunoreactive (PDH-IR) neurons innervating optic lobe neuropil in the blowfly and the cockroadh. In the blowfly the cell bodies of these neurons are located at the anterior base of the medulla. At least eight PDH-IR cell bodies of two size classes can be distinguished: 4 larger and 4 smaller. Branching immunoreactive fibers invade three layers in the medulla neuropil, and one stratum distal and one proximal to the lamina synaptic layer. A few fibers can also be seen invading the basal lobula and the lobula plate. The fibers distal to the lamina appear to be derived from two of the large PDH-IR cell bodies which also send processes into the medulla. These neurons share many features in their lamina-medulla morphology with the serotonin immunoreactive neurons LBO-5HT described earlier (see Nässel 1988). It could be demonstrated by immunocytochemical double labeling that the serotonin and PDH immunoreactivities are located in two separate sets of neurons. In the cockroach optic lobe PDH-IR processes were found to invade the lamina synaptic region and form a diffuse distribution in the medulla. The numerous cell bodies of the lamina-medulla cells in the cockroach are located basal to the lamina in two clusters. Additional PDH-IR cell bodies could be found at the anterior base of the medulla. The distribution and morphology of serotonin-immunoreactive neurons in the cockroach lamina was found to be very similar to the PDH-IR ones. It is hence tempting to speculate that in both species the PDH- and serotonin-immunoreactive neurons are functionally coupled with common follower neurons. These neurons may be candidates for regulating large numbers of units in the visual system.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed2004

Descending control of body attitude in the cockroach Blaberus discoidalis and its role in incline climbing.

Unlike intact animals, cockroaches with bilateral circumoesophageal connective lesions have difficulty climbing up smooth inclines. Typically, they slipped badly or even fell over backward before traveling more than 1.5 body lengths up the incline. The major problem involves increased slippage of the front and sometimes middle legs. Periods of front leg slipping are correlated with excess body elevation that pushes the height of the head to 11 mm above the substrate. Intact animals control body attitude very well on the incline, only rarely rearing above 11 mm. Cockroaches with bilateral circumoesophageal connective lesions spend considerable time above this critical amplitude and slipping increases with amplitude above that value. We conclude that circumoesophageal lesion compromises the insect's ability to control body attitude on the incline and this deficit contributes to the inability of lesioned cockroaches to climb steep inclines. A separate body attitude deficit was noted on steps. Upon climbing to the top of a barrier, intact animals bend their body between the first and second thoracic segments. This action maintains good leg mechanics throughout the climb. Cockroaches with bilateral circumoesophageal connective lesions fail to perform this downward flexion. A beneficial role for similar body flexion in simple robots is described in the Discussion.

Animals↗
PubMed2006

A model of antennal wall-following and escape in the cockroach.

Cockroaches exploit tactile cues from their antennae to avoid predators. During escape running the same sensors are used to follow walls. We hypothesise that selection of these mutually exclusive behaviours can be explained without representation of the stimulus or an explicit switching mechanism. A neural model is presented that embodies this hypothesis. The model incorporates behavioural and neurophysiological data and is embedded in a mobile robot in order to test the response to stimuli in the real world. The system is shown to account for data on escape direction and high-speed wall-following in the cockroach, including the counter-intuitive observation that faster running cockroaches maintain a closer distance to the wall. The wall-following behaviour is extended to include discrimination of tactile escape cues according to behavioural context. We conclude by highlighting questions arising from the robot experiments that suggest interesting hypotheses to test in the cockroach.

Animals↗
PubMed2005

Cockroach allergens.

Cockroaches produce several potent allergens associated with sensitization and the development of asthma. Many of these allergens have been cloned and produced as biologically active recombinant proteins. Three-dimensional structure and molecular modeling, in addition to studies on the biological functions of these proteins in the cockroach, have provided new insights into the ability of these allergens to cause immunoglobulin E antibody responses. Recent studies have pointed to a potential role of recombinant cockroach allergens for diagnosis and the development of novel therapeutic strategies that may benefit cockroach-allergic patients.

Allergens↗
PubMed1987

A hypoglycemic factor from the corpus cardiacum of the American cockroach Periplaneta americana.

Thin-layer chromatography of cockroach corpora cardiaca (cc) extracts revealed a fraction (F1 in solvent system 1) which had hyperlipemic activity in locusts and which differed in mobility from synthetic locust adipokinetic hormone I (AKH I). Fractions 4 and 5 exhibited hypolipemic activity when injected into locusts. Pooled samples of these fractions caused a diminution of carbohydrate levels in the cockroach. Bovine insulin mimicked both these effects. No change in hemolymph lipid was evident in the cockroach after injection of either CC fractions 4 and 5 or bovine insulin. Both the active fraction from the cockroach CC and bovine insulin caused a decrease in hemolymph carbohydrate in neck-ligated locusts. Injection of locust hypolipemic hormone, separated from locust CC storage lobes by TLC, into neck-ligated locusts also caused a decrease in hemolymph carbohydrate concentration. Normal locusts showed no change in hemolymph carbohydrate.

Animals↗
PubMed1987

Opioid involvement in the control of feeding in an insect, the American cockroach.

Administration of the kappa opiate agonist, U-50,488H (0.10-10 mg/kg), produced over three hours a significant dose-dependent increase in the ingestive responses of free feeding American cockroaches, Periplaneta americana. These effects could be decreased by the opiate antagonist, naloxone (1.0 mg/kg), with naloxone by itself blocking the augmented feeding responses of food-deprived cockroaches. The mu opiate agonist, morphine (1.0-20 mg/kg) caused a significant dose-dependent and naloxone-reversible increase in the locomotory activity of cockroaches. These results suggest that opioid systems may be involved in the control of the feeding in cockroaches in a manner analogous to that proposed for vertebrates.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMedDate not supplied

Bacterial pathogens isolated from cockroaches trapped from paediatric wards in peninsular Malaysia.

A survey was conducted in 4 paediatric wards in Malaysia to determine the distribution of various species of cockroaches and to examine their gut contents for bacteria. Cockroaches were trapped from food dispensing areas (kitchens), store rooms, cupboards and open wards. 104 cockroaches were caught, consisting of Periplaneta americana (67.3%), Blattella germanica (26%), P. brunnea (4.8%), and Supella longipalpa (1.9%). Bacteria were isolated from all cockroaches except 3 P. americana. Many bacterial species were identified, including the pathogenic and potentially pathogenic species Shigella boydii, S. dysenteriae, Salmonella typhimurium, Klebseilla oxytoca, K. ozaena and Serratia marcescens.

Animals↗
PubMed1993

Atopic profile of inner-city asthma with a comparative analysis on the cockroach-sensitive and ragweed-sensitive subgroups.

BACKGROUND: Inner-city asthma is well known for its high risk of mortality. To better understand urban asthma, we examined clinical characteristics and aeroallergen sensitivities of 592 of 680 consecutive urban Chicago residents with asthma. METHODS: A total of 227 male and 453 female subjects who met the criteria for the study were registered. A comprehensive clinical evaluation was followed by allergy skin testing (prick and intradermal testing) with 10 groupings (5 indoor and 5 outdoor) of common aeroallergens. Serum total IgE and selective antigen-specific IgE levels, including cockroach-specific IgE, were routinely measured. A total of 592 (196 male and 396 female) subjects with an average age of 35 years were skin tested. The average duration of asthma was 12.6 years, and 31% of the population was receiving corticosteroids. RESULTS: Aeroallergen sensitivity was noted in 85%, and 94 subjects (15%) were nonallergic. House dust sensitivity (76%) was most prevalent, distantly followed by sensitivity to cockroach (48%), ragweed (45%), other weeds (42%), cat (40%), and dust mite (24%). The average number of aeroallergen sensitivities detected was 4 of 10 groupings of both indoor and outdoor allergens. Twenty percent of subjects were allergic to only indoor allergens, whereas 4% were allergic to outdoor allergens only. Serum IgE was 245 +/- 17.3 IU/ml (geometric mean+SEM), and 74% of 444 serum samples showed IgE antibody levels greater than or equal to 100 IU/ml. A cockroach-sensitive subgroup (283 subjects) had longer duration of asthma (p < 0.0001) and fewer additional aeroallergen sensitivities (p < 0.0001) than the ragweed-sensitive subgroup (264 subjects). CONCLUSION: The results indicate that a great majority (85%) of inner-city Chicago residents with asthma have atopic asthma, as demonstrated by highly elevated IgE levels and multiple aeroallergen sensitivities. Sensitivity to indoor allergens is more prevalent than sensitivity to outdoor allergens. The subjects with cockroach-sensitive asthma appear to be a distinctive subgroup characterized by chronicity and elevated serum IgE antibody levels with fewer aeroallergen skin test sensitivities.

Adolescent↗
PubMed1993

In vitro translation of RNA from the German cockroach Blattella germanica.

The translation of mRNA within total RNA of German (Blattella germanica) cockroaches was performed using a rabbit reticulocyte lysate system. Analysis of the translation products by SDS-PAGE and combined autoradiography revealed several synthesized proteins with apparent molecular weights ranging from 20 kD to 110 kD. SDS-PAGE/Western blotting of non-radiolabeled translation products and incubation with human serum with IgE to cockroach allergens showed the presence of a 36 kD and 50 kD allergen. The confirmation of the translation of the cockroach allergens from total RNA is an important first step in the cloning of cockroach allergens.

Allergens↗
PubMed1993

Vector potential of the German cockroach in dissemination of Pseudomonas aeruginosa.

Survival time studies of Pseudomonas aeruginosa in cockroaches (Blattella germanica) were carried out under standard laboratory conditions. Cockroaches were fed with graded doses (10(2), 10(5) or 10(7) per insect) of P. aeruginosa. Depending on the excretion of P. aeruginosa the cockroaches were categorized as non-excretors, intermittent excretors or continuous excretors. When a dose of 10(2) P. aeruginosa was used all the insects were non-excretors but with doses of 10(5) or 10(7) per insect, P. aeruginosa multiplied in the gut of the cockroaches and was excreted for up to 114 days. The significance of these findings is discussed.

Animals↗
PubMedDate not supplied

kdr-Type resistance in insects with special reference to the German cockroach, Blattella germanica.

The phenomenon of knockdown resistance (kdr) was first noted in the housefly (Musca domestica), and has subsequently be found (i.e. kdr-type resistance) in several other insect pests including the German cockroach (Blattella germanica). This type of resistance causes insensitivity of the nervous system to pyrethroids, DDT and a limited number of sodium channel neurotoxins. In the German cockroach, kdr-type resistance is incompletely recessive, monogenic and not sex linked or due to cytoplasmic factors. Additionally, kdr-type resistance is not associated with a change in sodium channel density. kdr or kdr-type loci are tightly linked or identical to the para-homologous sodium channel locus in German cockroach, housefly and tobacco budworm (Heliothis virescens), suggesting that kdr and kdr-type resistance are due to mutations in the para-homologous sodium channel gene. kdr-Type resistance in the German cockroach appears similar, although not necessarily identical, to kdr in houseflies.

Animals↗
PubMed1987

Some aspects on L-dopa decarboxylase and p-tyrosine decarboxylase in the central nervous and peripheral tissues of the American cockroach Periplaneta americana.

1. Aromatic amino acid decarboxylase activities toward L-DOPA (L-3,4-dihydroxyphenylalanine), 5-HTP (5-hydroxytryptophan) and p-tyrosine in different tissues of the sclerotized and newly ecdysed cockroach were analyzed. 2. The ratios of enzyme activity with regard to L-DOPA and p-tyrosine varied considerably in the tissues and between the two different growth stages. 3. A DOPA decarboxylase and a p-tyrosine decarboxylase were separated by gel filtration and ion exchange chromatography. 4. The optimal pH requirement for both enzymes was 7.5 with the exception of the one decarboxylating 5-HTP. 5. The molecular weights of the cockroach brain DOPA decarboxylase and tyrosine decarboxylase were estimated to be 120,000 and 100,000, respectively. 6. Unlike the mammalian aromatic amino acid decarboxylase, the cockroach DOPA decarboxylase cannot be activated by a small amount of benzene. 7. An increase of over 50-fold of DOPA decarboxylase activity and a 50% reduction of tyrosine decarboxylase activity in the epidermal tissue of the newly ecdysed animals was observed. 8. In the fully sclerotized cockroach, a reversible endogenous inhibitor(s) of DOPA decarboxylase in the integument was observed, suggesting that the DOPA decarboxylase is suppressed in the epidermal tissues when ecdysis does not occur.

Animals↗
PubMed2004

Abatement of cockroach allergens (Bla g 1 and Bla g 2) in low-income, urban housing: month 12 continuation results.

BACKGROUND: In the first 6 months of this previously published, randomized trial, the combined intervention of occupant education, insecticide bait application, and professional cleaning significantly reduced cockroach numbers and Bla g 1 allergen levels in inner-city homes. OBJECTIVE: This continuation study investigated whether the cockroach allergen reductions achieved by month 6 could be maintained through month 12 with insecticide application alone. METHODS: Because we had agreed to place insecticide bait in control homes at the conclusion of the first study, intervention and control homes were treated with insecticide bait at months 6 and 9. No other intervention was conducted in either arm. Vacuumed dust and swab samples were collected at month 12. Twenty-one of the 31 original homes completed the 12-month study. RESULTS: Among the original intervention homes, Bla g 1 concentrations remained essentially unchanged from months 6 to 12. However, among the crossed-over control homes, the geometric mean Bla g 1 concentrations (Units per gram of dust) decreased from 287 to 14.4 for kitchen floors (95% reduction), from 28.8 to 5.6 for living room floors/sofas (81% reduction), from 26.7 to 4.7 for bedroom floors (82% reduction), and from 7.2 to 2.4 for beds (67% reduction). At month 12, Bla g 1 concentrations did not significantly differ between intervention and crossed-over control homes (P >.64 at each location). Similar results were seen for the allergen Bla g 2. CONCLUSIONS: Reductions in cockroach allergen concentrations achieved through the combined intervention of occupant education, insecticide application, and professional cleaning can be maintained with continued cockroach control. Surprisingly, and in contrast to other studies, insecticide application alone significantly lowered allergen concentrations in the crossed-over control homes. This unexpected result is being tested further in another randomized trial.

Allergens↗
PubMed2005

Peptidomics of neurohemal organs from species of the cockroach family Blattidae: how do neuropeptides of closely related species differ?

The primary structures and molecular mass data of neuropeptides that are released from major neuroendocrine sites of the American cockroach, Periplaneta americana, are well known. In the current study we extensively surveyed neuropeptides of the corpora cardiaca, the corpora allata and the abdominal perisympathetic organs, from 14 related cockroach species belonging to the family Blattidae. Mainly, this survey was executed by using mass spectrometric methods (MALDI-TOF MS). Peptides which appeared to be modified, as judged from their mass data and comparison with known data from P. americana, were fragmented by means of the post-source decay technique to determine their amino acid sequence. Single organ preparations sufficed to reveal the peptide pattern in neurohemal organs and to identify species-specific modifications, making it possible to glean information also from tissues of less abundant species that were caught during field trips. The peptide inventory described in this study is very typical of cockroaches of the family Blattidae and clearly separates this taxon from other taxa of cockroaches. The majority of neuropeptides was identical in all investigated species. Some peptides, however, displayed remarkable variations in their sequence which hint to a differential rate of modification among peptides of the same neuropeptide family. These modifications serve to distinguish further relatedness of taxa within the Blattidae.

Amino Acid Sequence↗
PubMed2002

Toxicity of cobra venom components to cockroach Gromphadorhina portentosa.

The toxicity of the Thailand and Middle-Asian cobra venoms as well as of their isolated components (neurotoxins, cytotoxins, phospholipases and some others) for cockroach Gromphadorhina portentosa was studied. It was found that, as compared to mammals, cockroaches are more resistant to cobra venoms and their components. At intraabdominal injection the most toxic for cockroaches were cytotoxins (LD(50) 1.5-2.3 nmol/g). Acidic phospholipase A(2) CM II is less active (2.85 nmol/g), while alpha-neurotoxins, being the most toxic venom components for mice (LD(50) 0.01-0.03 nmol/g), are not toxic for cockroaches at doses up to 15 nmol/g.

Animals↗