Cockroach Periplaneta Americana Research Articles

Spatiotemporal expression patterns of thymosin and its immune regulation after bacterial stimulation in American cockroach (Periplaneta americana)

AbstractThymosin is a physiologically active polypeptide hormone which has many functions involved in promoting wound healing, promoting hair growth, and accelerating tissue and organ regeneration. American cockroach (Periplaneta americana) has three subtypes thymosin (THY1, THY2, THY3) which are different splices from the same thymosin gene. Real‐time PCR was used to detect and analyze the expression differences of THY1 and THY2 in different stages, sexes, tissues and after stimulation by bacteria. Thymosins were expressed in adult, eclosion, and ootheca, and their expression levels were significantly up‐regulated during the eclosion period, showing the thymosin might be involved in the eclosion process. The expression levels of thymosins in females were higher than males, and the differences in eclosion stages were more significant (P < 0.01), indicating that they were closely related to development and female reproduction. The expressions of THY1 and THY2 in hemolymph were significantly higher (P < 0.01) than that in other tissues. The up‐regulated expression of thymosin in two immune‐related tissues (Hemolymph and adipose) after Escherichia coli stimulation further confirmed its involvement in the immune response. Our research would provide a basis for screening of novel pesticides target genes.

The vitellogenin receptor functionality of the migratory locust depends on its phosphorylation by juvenile hormone

Vitellogenin receptor (VgR) plays a pivotal role in ovarian vitellogenin (Vg) uptake and vertical transmission of pathogenic microbes and Wolbachia symbionts. However, the regulatory mechanisms of VgR action as an endocytic receptor and translocation from oocyte cytoplasm to the membrane remain poorly understood. Here, by using the migratory locust Locusta migratoria as a model system, we report that juvenile hormone (JH) promotes VgR phosphorylation at Ser1361 in the second EGF-precursor homology domain. A signaling cascade including GPCR, PLC, extracellular calcium, and PKC-ι is involved in JH-stimulated VgR phosphorylation. This posttranslational regulation is a prerequisite for VgR binding to Vg on the external surface of the oocyte membrane and subsequent VgR/Vg endocytosis. Acidification, a condition in endosomes, induces VgR dephosphorylation along with the dissociation of Vg from VgR. Phosphorylation modification is also required for VgR recycling from oocyte cytoplasm to the membrane. Additionally, VgR phosphorylation and its requirement for Vg uptake and VgR recycling are evolutionarily conserved in other representative insects including the cockroach Periplaneta americana and the cotton bollworm Helicoverpa armigera This study fills an important knowledge gap of low-density lipoprotein receptors in posttranslational regulation, endocytosis, and intracellular recycling.

Study the pathogenicity of the bacteria associated with Periplanta americana cockroach on Gelleria mollonella. L worm larva

In this study, the bacterial genera associated with the Periplaneta americana cockroach were isolated from the residential areas and nurseries in Baghdad city with concentrations 10-2, 10-4, 10-6 and their effect on the larvae of Gelleria mollonella. L worm was studied in the laboratory by food spraying method. Conclusion: The results showed that the highest percentage of larvae mortality was at the concentration 10-2 (33.33%) for both Acinetobacter lwoffii and Enterobacter cloacae bacteria. While the highest rate of larvae mortality was at the concentration 10-4 (33.33%) for each of Pseudomonas oleovorans, Acinetobacter baumannii, Acinetobacter lwoffii and Klebsiella pneumoniae, whereas the concentration 10-6 showed the highest mortality rate (50%) of Pseudomonas oleovorans and Klebsiellaella bacteria. Results of the study showed predominance of the effect of Pseudomonas oleovorans and Klebsiella pneumonia on the mortality rate of the larvae of the great Gelleria mellonell L. worm as it was 50%, while the effect of Enterobacter cloacae and Pseudomonas oleovorans yielded the highest mortality rate of 33.33% at each of the concentrations 10-2,10-4 10-6 whereas the results showed that the concentration 10-2 for each of Proteus mirabilis, Escherichia coli, and Enterobacter aerogenes had no effect on larvae mortality.

ANTIBIOTIC SUSCEPTIBILITY TEST TOWARDS COCKROACH (PERIPLANETA AMERICANA) FOOT BACTERIA IN THE NUTRITION DEPARTMENT AREA OF PALU CITY HOSPITAL

Cockroaches (Periplaneta americana) are known to have potential as vectors of various pathogenic bacteria in various locations including the nutrition department area in the hospitals. Research related to the role of these animals as vectors of pathogenic bacteria has not been done. The provision of food in the hospital nutrition department has the potential for bacterial contamination from food, equipment, hospital staff, and the environment. Cockroaches can be a vector for spreading various nosocomial infectious diseases in hospitals. A descriptive method was used, and the data were obtained by bacterial isolation, Gram staining method, antibiotic sensitivity test, and bacterial identification using Microbact system software 2000. This study was carried out at the Biology Education Laboratory, Education and Teacher Training Faculty, Tadulako University. Based on the results of the study, 6 species of bacterial isolates from cockroach feet  in the nutrition department area of Palu city hospital, namely E. coli, S. arizonae, Salmonella sp., K. ozaenae, S. simulans, and S. enterica. Antibiotic sensitivity test showed that four bacteria exhibited multi-drug resistance to antibiotics Amoxycillin, Chloramphenicol and Vancomycin. Meanwhile,S. enterica was still sensitive to the five tested antibiotics namely Amoxycillin, Chloramphenicol, Ciprofloxacin, Ofloxacin, and Vancomycin. serious policies and handling are needed to control new types of vectors that carry diseases in humans.. meanwhile,S. entericawas still sensitive to the five tested antibiotics.

Concordance of skin test reactivity between indoor inhalant allergens among children with allergic respiratory disease

BackgroundIn vitro studies have demonstrated cross-reactivity among indoor allergen proteins in children with allergic respiratory diseases. However, there are only few studies evaluating in vivo response. A skin prick test (SPT) with commercial indoor solutions is widely used in clinical practice. We aimed to evaluate SPT agreement in children with allergic respiratory disease between pairs of common indoor allergens.MethodsWe reviewed SPT results of children 2 to 18 years old, diagnosed with respiratory allergic disease. Results from house dust mite (Dermatophagoides farinae, Dermatophagoides pteronyssinus), cockroach (Periplaneta americana, Blatella germanica), cat and dog were collected. Sensitization was defined as ≥ 3 mm in wheal diameter. Kappa coefficient (κ) was used to analyze sensitization concordance for each allergen pair.ResultsThe charts of 300 children, 187 (62.33%) males, were reviewed. Mean age was 7.43 ± 3.29 years with 183 (61%), 140 (46.67%), 45 (15%), 30 (10%) sensitizations to house dust mite (HDM), cockroach, cat and dog, respectively. Sensitization concordance between HDM and cockroach was moderate: κ = 0.53 (95% CI: 0.42–0.64). Moderate agreement occurred between dog and cat: κ = 0.41 (95%CI: 0.30–0.52). HDM-sensitized children showed poor concordance with both cat κ = 0.17 (95%CI: 0.09–0.24) and dog κ = 0.09 (95%CI: 0.03–0.14). There was also poor concordance between cockroach-sensitized children to cat κ = 0.19 (95%CI; 0.11–0.28) and dog κ = 0.11 (95%CI; 0.04–0.18).ConclusionWe demonstrated moderate agreement of SPT response between HDM and cockroach as well as dog and cat. This may be due to cross-reactivity. Component-resolved diagnosis should be considered in children with co-sensitization of these allergen pairs.

Determination of Carrier Parts of Some Microorganisms in Body of the American Cockroach Periplaneta americana in Some Parts of Mosul City

Compared to other organisms, insects are found in all the world. The diversity and evolutional success of insects depend on its relation with useful microorganisms. These microorganisms are found mostly in the intestines and epidermis of the insect. A Cockroach is one of the most important medical insects. All of the species of this insect live in dirty environments especially sewers. There are two species of disease-causing cockroaches: the German cockroach (Blatella germanica) and American cockroach (Periplaneta americana). The study aims at defining the role of P. americana as a carrier of disease-causing bacteria by isolating and determining these microorganisms from the body of the cockroach. The study included (18) samples of P. americana. Each sample was autopsied to get external parts as well as the digestive channel. These specimens underwent a bacteriological study to isolate and diagnose the species of bacteria and which parts carry them. Isolation results showed the diagnosing of (22) isolates of about 13 different species of bacteria, (82%) of isolates came from the external parts of the insect while (18%) isolated from the digestive channel. Most isolates belong to the family Enterobacteriaceae in 68.18%. First place went to Serratia marcescens with 36.36% of the isolated species then Kluyvera intermedia 13.64% . As for the rest species, all shared a ratio of 4.55%.

Microbial colonization promotes model cockroach gut tissue growth and development

BackgroundDigestive tissues are essential for diet processing and nutrient accessibility, especially in omnivores, and these functions occur despite and in collaboration with dynamic microbial communities that reside within and upon these tissues. Prolonged host development and reduced digestive tissue sizes have been observed in germ-free animals, and normal host phenotypes were recovered following the re-introduction of typical gut microbiomes via coprophagy. ResultsHigh-resolution histological analyses of Periplaneta americana cockroach digestive tissues revealed that total prevention of microbial colonization of the gut had severe impacts on the growth and development of gut tissues, especially the posterior midgut and anterior hindgut subcompartments that are expected to be colonized and inhabited by the greatest number of bacteria. Juveniles that were briefly exposed to normal gut microbiota exhibited a partial gut morphological recovery, suggesting that a single inoculation was insufficient. These data highlight gut microbiota as integral to normal growth and development of tissues they are in direct contact with and, more broadly, the organism in which they reside. ConclusionsWe draw on these data, host life history traits (i.e. multigenerational cohousing, molting, and filial coprophagy and exuvia feeding), and previous studies to suggest a host developmental model in which gut tissues reflect a conflict-collaboration dynamic where 1) nutrient-absorptive anterior midgut tissues are in competition with transient and resident bacteria for easily assimilable dietary nutrients and whose growth is least-affected by the presence of gut bacteria and 2) posterior midgut, anterior hindgut, and to a lesser degree, posterior hindgut tissues are significantly impacted by gut bacterial presence because they are occupied by the greatest number of bacteria and the host is relying upon, and thus collaborating with, them to assist with complex polysaccharide catabolism processing and nutrient provisioning (i.e. short-chain fatty acids).

Component-Resolved Diagnosis of American Cockroach (Periplaneta americana) Allergy in Patients From Different Geographical Areas

Background: Manifestation of respiratory allergy to American cockroach (Periplaneta americana) is prominent in the subtropical and tropical areas. However, co-existing perennial indoor inhalant allergies frequently compromise clinical diagnosis of cockroach allergy, and the analysis of sensitization pattern is limited by the lack of Periplaneta allergens widely available for component-resolved diagnostics (CRD).Objective: To evaluate a collection of previously described recombinant Periplaneta allergens for CRD in cockroach allergy.Methods: A panel of nine recombinant Periplaneta allergens (Per a 1–5, 7–10) was generated, purified, and subjected to physicochemical characterization by applying circular dichroism (CD) spectroscopy, dynamic light scattering (DLS), amino acid (AA) analysis, and mass spectrometry (MS). Patients (n = 117) from India, Korea, Venezuela, and Iran, reporting perennial respiratory indoor allergies with IgE sensitization to cockroach (P. americana and/or Blattella germanica), were included. The sensitization profile was monitored by the experimental ImmunoCAP testing.Results: ImmunoCAP testing confirmed IgE sensitization to Periplaneta and/or Blattella extract in 98 of 117 patients (r = 0.95). Five out of 117 patients were sensitized to only one of the two cockroach species. Within the whole study group, the prevalence of sensitization to individual allergens varied from 4% (Per a 2) to 50% (Per a 9), with the highest IgE values to Per a 9. Patients from four countries displayed different sensitization profiles at which Per a 3 and Per a 9 were identified as major allergens in India and Korea. Periplaneta-derived lipocalin and myosin light chain were characterized as new minor allergens, designated as Per a 4 and Per a 8. Periplaneta extract showed higher diagnostic sensitivity than all individual components combined, suggesting the existence of allergens yet to be discovered.Conclusion: Utilization of a panel of purified Periplaneta allergens revealed highly heterogeneous sensitization patterns and allowed the classification of lipocalin and myosin light chain from Periplaneta as new minor allergens.

Consensus driven by a minority in heterogenous groups of the cockroach Periplaneta americana

SummaryMany social species are able to perform collective decisions and reach consensus. However, how the interplay between social interactions, the diversity of preferences among the group members and the group size affects these dynamics is usually overlooked. The collective choice between odourous and odorless shelters is tested for the following three groups of social cockroaches (Periplaneta americana) which are solitary foragers: naive (individuals preferring the odorous shelter), conditioned (individuals without preference), and mixed (combining, unevenly, conditioned, and naive individuals). The robustness of the consensus is not affected by the naive individuals' proportion, but the rate and the frequency of selection of the odorous shelter are correlated to this proportion. In mixed groups, the naive individuals act as influencers. Simulations based on the mechanisms highlighted in our experiments predict that the consensus emerges only for intermediate group sizes. The universality of these mechanisms suggests that such phenomena are widely present in social systems.

Numerical tests of magnetoreception models assisted with behavioral experiments on American cockroaches

Many animals display sensitivity to external magnetic field, but it is only in the simplest organisms that the sensing mechanism is understood. Here we report on behavioural experiments where American cockroaches (Periplaneta americana) were subjected to periodically rotated external magnetic fields with a period of 10 min. The insects show increased activity when placed in a periodically rotated Earth-strength field, whereas this effect is diminished in a twelve times stronger periodically rotated field. We analyse established models of magnetoreception, the magnetite model and the radical pair model, in light of this adaptation result. A broad class of magnetite models, based on single-domain particles found in insects and assumption that better alignment of magnetic grains towards the external field yields better sensing and higher insect activity, is shown to be excluded by the measured data. The radical-pair model explains the data if we assume that contrast in the chemical yield on the order of one in a thousand is perceivable by the animal, and that there also exists a threshold value for detection, attained in an Earth-strength field but not in the stronger field.

Establishment and Maintenance of Gnotobiotic American Cockroaches (<em>Periplaneta americana</em>)

Gnotobiotic animals are a powerful tool for the study of controls on microbiome structure and function. Presented here is a protocol for the establishment and maintenance of gnotobiotic American cockroaches (Periplaneta americana). This approach includes built-in sterility checks for ongoing quality control. Gnotobiotic insects are defined here as cockroaches that still contain their vertically transmitted endosymbiont (Blattabacterium) but lack other microbes that normally reside on their surface and in their digestive tract. For this protocol, egg cases (oothecae) are removed from a (nonsterile) stock colony and surface sterilized. Once collected and sterilized, the oothecae are incubated at 30 °C for approximately 4−6 weeks on brain-heart infusion (BHI) agar until they hatch or are removed due to contamination. Hatched nymphs are transferred to an Erlenmeyer flask containing a BHI floor, sterile water, and sterile rat food. To ensure that the nymphs are not housing microbes that are unable to grow on BHI in the given conditions, an additional quality control measure uses restriction fragment-length polymorphism (RFLP) to test for nonendosymbiotic microbes. Gnotobiotic nymphs generated using this approach can be inoculated with simple or complex microbial communities and used as a tool in gut microbiome studies.

Establishment and Maintenance of Gnotobiotic American Cockroaches (Periplaneta americana).

Gnotobiotic animals are a powerful tool for the study of controls on microbiome structure and function. Presented here is a protocol for the establishment and maintenance of gnotobiotic American cockroaches (Periplaneta americana). This approach includes built-in sterility checks for ongoing quality control. Gnotobiotic insects are defined here as cockroaches that still contain their vertically transmitted endosymbiont (Blattabacterium) but lack other microbes that normally reside on their surface and in their digestive tract. For this protocol, egg cases (oothecae) are removed from a (nonsterile) stock colony and surface sterilized. Once collected and sterilized, the oothecae are incubated at 30 °C for approximately 4-6 weeks on brain-heart infusion (BHI) agar until they hatch or are removed due to contamination. Hatched nymphs are transferred to an Erlenmeyer flask containing a BHI floor, sterile water, and sterile rat food. To ensure that the nymphs are not housing microbes that are unable to grow on BHI in the given conditions, an additional quality control measure uses restriction fragment-length polymorphism (RFLP) to test for nonendosymbiotic microbes. Gnotobiotic nymphs generated using this approach can be inoculated with simple or complex microbial communities and used as a tool in gut microbiome studies.

Cockroach exposure and its allergy sensitization in asthma patients.

Asthma is a heterogeneous disease with distinct phenotypes. Serum tIgE, SSIgE and SPT are the methods of evaluating allergen sensitization. The present study evaluates the exposure and sensitization to cockroach (Periplaneta americana) antigens in asthma patients in a metropolitan city of India. The study enrolled 200 consecutive bronchial asthma patients, diagnosed as per GINA guidelines. As per history of exposure to cockroaches, the patients are divided in two groups as exposed and non-exposed asthmatic. All the enrolled subjects underwent SPT against common aeroallergens including cockroach, spirometry and estimation of tIgE level and SSIgE against cockroach. Out of 200 asthma patients, a total of 114 (57%) asthmatic were found SPT positive against one of the common aeroallergens, of which 68 (34%) showed SPT sensitivity against cockroach. A total of 103 (51.5%) patients were found exposed to cockroaches. In the cockroach exposed group, the mean serum tIgE was found significantly higher than the non-exposed group (569.31±224.64 vs 479.29±237 IU/ml; p=0.007). The mean SSIgE against cockroach in exposed groups was found not significant than non-expose group (4.87±11.19 vs 4.11±8.39 KUA/L; p=0.589). The mean tIgE was also not significant in atopic compared to non-atopic asthmatic (553.25±218.12 IU/ml vs 489.1±251.16 IU/ml; p=0.056). The mean SSIgE against cockroach was 5.66±10.45 KUA/L for atopic and 2.96±8.98 KUA/L for non-atopic (p=0.054). The airway obstruction was almost the same in both groups. Asthmatic patients who were exposed to cockroach and atopic had high tIgE, SSIgE levels and SPT positivity against cockroach antigen compared to non-exposed patients.

Neonicotinoids stimulate H2-limited methane emission in Periplaneta americana through the regulation of gut bacterium community

Methane emitted by insects is considered to be an important source of atmospheric methane. Here we report the stimulation of methane emission in the cockroach Periplaneta americana and termite Coptotermes chaohuensis, insects with abundant methanogens, by neonicotinoids, insecticides widely used to control insect pests. Cycloxaprid (CYC) and imidacloprid (IMI) caused foregut expansion in P. americana, and increased the methane emission. Antibiotics mostly eliminated the effects. In P. americana guts, hydrogen levels increased and pH values decreased, which could be significantly explained by the gut bacterium community change. The proportion of several bacterium genera increased in guts following CYC treatment, and two genera from four could generate hydrogen. Hydrogen is a central intermediate in methanogenesis. All increased methanogens in both foregut and hindgut used hydrogen as electron donor to produce methane. Besides, the up-regulation of mcrA, encoding the enzyme for the final step of methanogenesis suggested the enhanced methane production ability in present methanogens. In the termite, hydrogen levels in gut and methane emission also significantly increased after neonicotinoid treatment, which was similar to the results in P. americana. In summary, neonicotinoids changed bacterium community in P. americana gut to generate more hydrogen, which then stimulated gut methanogens to produce and emit more methane. The finding raised a new concern over neonicotinoid applications, and might be a potential environmental risk associated with atmospheric methane.

The Effect of Using Different Levels of American Cockroach (Periplaneta americana) powder on Productive and Physiological Performance of Japanese Quail (Coturnix japonica)

This study aimed to investigate the effect of using different levels of American cockroach (Periplaneta americana) powder on productive and physiological performance of Japanese quail (Coturnix japonica). One hundred and thirty-five, 45 days-old of Japanese quail females were randomly divided into three groups (45 females for each). Each group has three replicates (15 females per each). The groups were included: The first group was fed on experimental diet included with 0 % of insect powder and 6% of protein concentration as the control. The second group was fed on experimental diet included with 3% of protein concentration and 3% of insect powder. The third group was fed on experimental diet included with 0 % of protein concentration and 6% of insect powder. The results showed no significant in the egg weight, egg mass, feed conversion ratio and mortality among groups. The birds in the third group were recorded a significant increase (P ≤ 0.05) in the egg production (%), on the other hand, it recorded a less value in the feed intake compared to other groups. The results of relative weight of ovaries and oviducts showed the birds in the third group were recorded a significant increase (P ≤ 0.05) compared to other groups. On the other hand, the second group was recorded a significant increase (P ≤ 0.05) compared to first group (control). The results were indicated no significant in the levels of estrogen hormone among groups. While, the results of the levels of follicle stimulating hormone and luteinizing hormone were indicated a significant increase (P ≤ 0.05) in the third group compared to other groups. In addition to, the second group was recorded a significant increase (P ≤ 0.05) compared to first group (control). In conclusions, so far proves the potential of the American cockroach (P. americana) meal for use in quail production systems. American cockroach (P. americana) food based feed can completely replace protein sources by 100 per cent without negative effect on the productive performance of quail and, in some ways, can achieve better than conventional protein based feeds such as protein concentrations. On the other hand, the American cockroach (P. americana) meal improved physiological performance of quail.

Oxazosulfyl, a Novel Sulfyl Insecticide, Binds to and Stabilizes the Voltage-Gated Sodium Channels in the Slow-Inactivated State

Oxazosulfyl is the first representative of a novel sulfyl class of insecticides with a potent and cross-spectrum insecticidal activity, albeit with an unclear mechanism of action. As a potential agent of pest control in rice fields, we investigated the action of oxazosulfyl on the nervous system and voltage-gated sodium channels in insects. After the injection of 10 μg of oxazosulfyl, American cockroaches (Periplaneta americana) were quickly paralyzed, which persisted for more than 7 days. Extracellular recordings revealed a depressed spontaneous nerve activity in the cockroaches injected with oxazosulfyl, which specifically affected the voltage-gated sodium channels (in German cockroaches (Blattella germanica) expressed in Xenopus oocytes) in the slow-inactivated state resulting in the inhibition of sodium currents. The potency of oxazosulfyl and other sodium channel blockers to block sodium channels was consistent with their insecticidal activity. Thus, we conclude that the action mode of oxazosulfyl involves the state-dependent blockage of voltage-gated sodium channels.

Susceptibilidad de Periplaneta americana (Blattodea: Blattidae) a dos aislados de Steinernema rarum (Rhabditida: Steinernematidae) de la provincia de Córdoba, Argentina

The effect of Steinernema rarum (Doucet) ((OLI) and N105 strains) from Córdoba province on the American cockroach Periplaneta americana (L.) was evaluated. Two doses: 3,200 and 6,400 infective juveniles (IJs) / host were used and a control group was considered. Forty-nine insects per treatment were evaluated. Infections were maintained at 25 ± 1 ºC. Dead insects were recorded every 24 h during 15 days. Steinernema rarum (OLI) caused a mortality of 67% and 89%, for 3,200 and 6,400 JIs, respectively. With isolate N105, mortality never exceeded 65%. The two isolates completed their life cycle with the production and emergence of JIs in P. americana: for S. rarum (OLI), 255,215 ± 3 x 104 and 328,102 ± 3 x 104, for D3200 and D6400, respectively; for S. rarum N105, 142,451 ± 3 x 104 and 188,253 ± 3 x 104, D3200 and D6400, respectively. Significant differences between strains for the average number of JIs (F3,126 = 5,26; p ≤ 0,001) were registered. Based on these results, Blattodea is incorporated into the range of hosts of S. rarum (OLI) and it is disclosed that P. americana is the first host for S. rarum N105 in laboratory

Electromagnetic field and TGF-\u03b2 enhance the compensatory plasticity after sensory nerve injury in cockroach Periplaneta americana

Recovery of function after sensory nerves injury involves compensatory plasticity, which can be observed in invertebrates. The aim of the study was the evaluation of compensatory plasticity in the cockroach (Periplaneta americana) nervous system after the sensory nerve injury and assessment of the effect of electromagnetic field exposure (EMF, 50 Hz, 7 mT) and TGF-β on this process. The bioelectrical activities of nerves (pre-and post-synaptic parts of the sensory path) were recorded under wind stimulation of the cerci before and after right cercus ablation and in insects exposed to EMF and treated with TGF-β. Ablation of the right cercus caused an increase of activity of the left presynaptic part of the sensory path. Exposure to EMF and TGF-β induced an increase of activity in both parts of the sensory path. This suggests strengthening effects of EMF and TGF-β on the insect ability to recognize stimuli after one cercus ablation. Data from locomotor tests proved electrophysiological results. The takeover of the function of one cercus by the second one proves the existence of compensatory plasticity in the cockroach escape system, which makes it a good model for studying compensatory plasticity. We recommend further research on EMF as a useful factor in neurorehabilitation.

Antagonistic Activity of Bacteria Isolated from the Periplaneta americana L. Gut against Some Multidrug-Resistant Human Pathogens.

The insect gut is home to a wide range of microorganisms, including several bacterial species. Such bacterial symbionts provide various benefits to their insect hosts. One of such services is providing metabolites that resist infections. Little data are available about gut-inhabiting bacteria for several insect groups. Through the present work, the gut bacteria associated with the American cockroach (Periplaneta americana L.) were isolated, identified, and studied for their potential antimicrobial activity against multidrug-resistant (MDR) human pathogens. The cockroaches were collected from three different environmental sites. Gut bacteria were isolated, and sixteen species of bacteria were identified using Vitek MALDI-TOF MS. The antagonistic activity of the identified bacteria was tested against a panel of multidrug-resistant bacteria and fungi, namely: methicillin-resistant Staphylococcus aureus (MRSA) (clinical isolate), Streptococcus mutans Clarke (RCMB 017(1) ATCC ® 25175™) (Gram-positive bacteria), Enterobacter cloacae (RCMB 001(1) ATCC® 23355™) and Salmonella enterica (ATCC® 25566™) (Gram-negative bacteria). The isolates were also tested against human pathogenic fungi such as Candida albicans (RCMB005003(1) ATCC® 10231™), Aspergillus niger (RCMB002005), Aspergillus fumigatus (RCMB002008), Aspergillus flavus (RCMB002002), and Penicillium italicum (RCMB 001018(1) IMI193019). The results indicated that some bacterial species from the cockroach gut could antagonize the growth activity of all the tested pathogens. Such antimicrobial properties could ultimately lead to the future development of therapeutic drugs. The evaluation and mode of action of antagonistic gut bacteria against the most affected MDR pathogens were demonstrated using transmission electron microscopy (TEM).

Why do zombies clean themselves? An initial test of the antimicrobial hypothesis in a parasite‐host relationship

The emerald jewel wasp Ampulex compressa attacks the cockroach Periplaneta americana which serves as the host of the parasite and injects venom directly into the cockroach’s central nervous system. The cockroach responds by excessive grooming and cleaning its entire body with its legs and mandibles. The antimicrobial hypothesis suggests that self-grooming is adaptive for the parasite because it decreases ectoparasite and fungal infection rates from the cockroach’s cuticle in order to prevent infection of the wasp’s larvae. We demonstrated under laboratory conditions that microbial prevalence was not higher in stung cockroaches experimentally prevented from self-grooming than in self-groomed ones.