Genome Size Evaluations in Cockroaches: New Entries

Background: Ten years ago the main Genome Size (GS) database contained records for 830 insects; although this number has now nearly doubled, 1645 (Gregory 2011 vs Gregory 2021 databases), the paucity of records highlights both the difficulty of animal field trapping and the time-consuming laboratory techniques to evaluate them. Thus, new entries are necessary to reach a satisfactory GS panorama for cockroaches. Results: We report GS values for nine cockroaches (order Blattodea, families Blattidae, Blaberidae and Ectobiidae, ex Blattelidae,), three of which are original additions to the ten already present in the GS database: the death’s head roach (Blaberus craniifer), the Surinam cockroach (Pycnoscelus surinamensis) and the Madeira cockroach (Leucophaea maderae). Three of our values confirm the existing data for the German (Blattella germanica), the oriental (Blatta orientalis) and the giant Mexican (Blabera fusca) cockroaches. Regarding the GS of the American cockroach (Periplaneta americana) the GS database contains two contrasting values (2.72 vs 3.41 pg). We suggest that the 2.72 pg value is likely to be the correct GS as it strikingly similar to our sperm DNA content evaluation (2.80 ± 0.11 pg). Finally, we suggest halving the published GS of the Argentine cockroach Blaptica dubia and the spotted cockroach (the gray cockroach) Nauphoeta cinerea as our estimates come from the evaluation of the sperm DNA content. The data already reported in the literature are based on DNA contents of neural cells (likely polyploid) obtained by grinding entire heads of animals.Conclusions: Although the paucity of the GS data does not allow firm considerations on the possible evolutionary role played by the GS in diversifying cockroach species, we offer two speculative hypotheses that need to be validated by increasing the available GS records: (i) the occurrence of a correlation between increasing 2N chromosome number and GS within the order Blattodea; and (ii) the possible occurrence of a polyploidization phenomenon doubling a basic GS of 0.58 pg of some termite families (superfamily Blattoidea, epifamily Termitoidae) up to the maximum GS value of 3.24 for the Blaberidae family within the order Blattodea (super-order Dictyoptera).

عزل الفطريات من حشرة الصرصور الأمريكي (Periplaneta americana) المحفوظة في متحف الحشرات بقسم وقاية النبات

أُجريت هذه الدراسة لعزل، وتشخيص بعض أنواع الفطريات المصاحبة لحشرة الصرصور الأمريكي Periplaneta americana L. (Orthroptera: Blattidae) المحفوظة بمتحف الحشرات بقسم وقاية النبات- كلية الزراعة- جامعة عمر المختار- البيضاء- ليبيا. جُمعت عشر حشرات من صناديق حفظ الحشرات تحوي بلورات النفثالين. فصلت الحشرة إلى أجزائها الأرجل، والأجنحة، وقرون الاستشعار، وأجزاء الفم، وعقمت سطحياً، وحضنت على الوسط الغذائي PSA. ثمانية أنواع من الفطريات تم عزلها وهي Alternaria altemata ، Aspergillus niger , terreus .A ,Beauvaria sp. , Madurella sp. , P. verrucosum ,umlla sp.الفطريات P. commune Penicillum sp. كانت محمولة على أجزاء من جسم الحشرة، كما بينت الدراسة أن الفطرA. niger كان أكثر الفطريات المعزولة تكرارا بنسبة 23.8%، وكثافة بلغت 41.7%, يليه الفطران A. altemata, P. verrucosum إذ بلغ التكرار9.5% و 7.1% وسجلت الكثافة 16.7%, 12.7% لكلا الفطرين على التوالي, وأقل نسبة كثافة كانت للفطرين terreus A. و Beauvaria spحيث بلغت 8.3% نستنتج من الدراسة أن الفطريات المعزولة هي من فطريات التخزين التي تهاجم الحشرات المحفوظة في المتاحف مما يعرضها للتلف.

Contact Toxicity of Various Stemona Collinsiae Root Extracts Against Periplaneta Americana (Dictyoptera: Blattodea) And Detection of Didehydrostemofoline Distribution in Tissue Using MALDI Imaging Mass Spectrometry

Contact toxicity against Periplaneta americana has never been tested with S. collinsiae root extract. Hexane, dichloromethane, ethanol and water extracts were tested in final-instar nymphs and adult P. americana by topical application method. The dichloromethane extract showed the high-est potency of contact toxicity against the final-instar nymphs (41-100% corrected mortality at 48 hours), lowest LC50 (1.5±0.2 %w/v at 48 hours), and lowest LT50 (36.1±0.8 hours at 10%w/v) while the water crude extract lacked the contact toxicity (0-0% corrected mortality at 48 hours). Signs of toxicity, such as excited movement, trembling body, motionlessness, and swollen abdomen segment including irregularly extended foregut were found at the both stages of P. americana dropping with solutions of dichloromethane extract. Detection of didehydrostemofoline distri-bution using IMS revealed that didehydrostemofoline distributed in the tissue of the dead fi-nal-instar nymph and adult P. americana contacting with dichloromethane extract, but it was not found in tissue of euthanized P. americana which exposed to the water extract. Didehydrostemo-foline in the extract was a cause of toxicity signs and death of P. americana via a contact route. Thus, dichloromethane extract and didehydrostemofoline could be used as an active ingredient and chemical marker in aerosol and spray formulations for cockroach control.

The Killing Power of Areca Seed Extract (Areca catechu L.) in the Control of Cockroaches (Periplaneta americana)

Cockroaches are one of the insects that can spread diseases such as dysentery, diarrhea, cholera, viral hepatitis. Therefore an insecticide that is safe for the environment is needed, one of which is areca seed (Areca caechu L.) which contains Polyphenols, Flavonoids, Tanins, and Alkaloids that are safe for the surrounding environment and do not leave high residues. The purpose of this study was to analyze the strength test to kill areca seed extract (Areca catechu L.) against cockroach populations. The research design used in this research is quasi experimental (Quasi Experimental), the sample in this study used 360 adult cockroaches (Periplaneta americana) measuring 3 cm. This study used the Mann-Whitney U test analysis to analyze the differences in the ability of areca seed extract (Areca catechu L.) in killing cockroach populations. The results showed that at a concentration of 100% it was more effective to kill cockroaches Periplaneta americana type because it can kill 91% of American perennial cockroaches within 24 hours. The conclusion of this study is that there are differences in concentration of areca catechu L. extract with variations of 80%, 90%, 100% where p = 0.000.

Insect Body Defence Reactions against Bee Venom: Do Adipokinetic Hormones Play a Role?

Bees originally developed their stinging apparatus and venom against members of their own species from other hives or against predatory insects. Nevertheless, the biological and biochemical response of arthropods to bee venom is not well studied. Thus, in this study, the physiological responses of a model insect species (American cockroach, Periplaneta americana) to honeybee venom were investigated. Bee venom toxins elicited severe stress (LD50 = 1.063 uL venom) resulting in a significant increase in adipokinetic hormones (AKHs) in the cockroach central nervous system and haemolymph. Venom treatment induced a large destruction of muscle cell ultrastructure, especially myofibrils and sarcomeres. Interestingly, co-application of venom with cockroach Peram-CAH-II AKH eliminated this effect. Envenomation modulated the levels of carbohydrates, lipids, and proteins in the haemolymph and the activity of digestive amylases, lipases, and proteases in the midgut. Bee venom significantly reduced vitellogenin levels in females. Dopamine and glutathione (GSH and GSSG) insignificantly increased after venom treatment. However, dopamine levels significantly increased after Peram-CAH-II application and after co-application with bee venom, while GSH and GSSG levels immediately increased after co-application. The results suggest a general reaction of the cockroach body to bee venom and at least a partial involvement of AKHs.

Ovicidal and Repellent Activities of Several Plant Essential Oils Against Periplaneta americana L. and Enhanced Activities from their Combined Formulation

Natural ovicidal and repellent agents against Periplaneta americana are in urgent need, and plant essential oils (EOs) can assume this role quite readily. In this study, ovicidal and repellent activities against Periplaneta americana of EOs from Cymbopogon citratus, Cinnamomum verum, Eucalyptus globulus, Illicium verum, and Zanthoxylum limonella in soybean oil and in ethyl alcohol were determined by topical and dual-choice assays, as well as 10% cypermethrin and a combined formulation of 5% C. verum EO + 5% I. verum EO. Cypermethrin at 10% provided the highest toxicity (100% inhibition rate) against the eggs, but only slightly higher than that (99.3%) provided by the combined EO formulation, while the highest repellent activity against the adults was provided by the combined formulation (89.5% repelled cockroaches at 48 h after treatment). In addition, all EO formulations in soybean oil provided higher ovicidal and repellent activities than in ethyl alcohol. To conclude, the combined EO formulation in soybean oil can replace cypermethrin because their efficacy was nearly equivalent, but the combination should be much safer to use.

Gastroprotective Effects of Periplaneta americana L. Extract Against Ethanol-Induced Gastric Ulcer in Mice by Suppressing Apoptosis-Related Pathways

Although Periplaneta americana L. and its modern preparation, Kangfuxin liquid, have been extensively applied for ulcerative diseases in gastrointestinal tract (e.g., gastric ulcer (GU) and ulcerative colitis, the effective components and potential mechanisms) remain unclear. In accordance with the accumulating research evidences, the relieving/exacerbating of GU is noticeably correlated to focal tissue programmed cell death. Herein, gastro-protective effects of the effective Periplaneta americana L. extract (PAE) fraction were assessed in vitro and in vivo, involving in programmed cell death-related signaling channels. To screen the effective PAE fraction exerting gastroprotective effects, several PAE fractions were gained based on a wide range of ethanol solution concentration, and they were assessed on ethanol-induced ulcer mice. Based on HPLC investigation with the use of nucleosides, the chemical composition of screened effective PAE, extracted by 20% ethanol, was analyzed in terms of quality control. Based on CCK-8 assay, the protective effects on GES-1 cells, impaired by ethanol, of PAE were assessed. After 3 days pre-treatment with PAE (200, 400, 800 mg/kg), the gastric lesions were assessed by tissue morphology, and periodic acid-schiff (PAS) staining, as well as hematoxylin and eosin (H&E) based histopathology-related investigation. The levels for inflammation cytokines (IL1-β, TNF-α, IL-18, PGE2, and IL-6), antioxidant indices (SOD and MDA) were examined via ELISA. In the meantime, based on Western Blotting assay, the expression levels of some programmed cell death-related protein targets (NLRP3, caspase-1, NF-κB p65, MyD88, and TLR4) were analyzed. As revealed from the results, PAE is capable of alleviating gastric mucosa impairment, suppressing the inflammatory cytokines, and down-regulating the MyD88/NF-κB channels. Accordingly, 20% ethanol extract of Periplaneta americana L. would contribute its gastroprotective effects, thereby providing the evidence that its anti-GU mechanisms correlated with inhibiting programmed cell death channel.

The Carrier Rate of Extended Spectrum Beta Lactamase (ESBL) Producing Bacteria in Cockroaches (Periplaneta americana) in Hospital and Community

Highlight :Bacteriologically for colonization of ESBL producing Enterobacteriaceae in cockroaches (Periplaneta americana) were analyzed.The prevalence of ESBL producing bacteria among cockroaches in hospitals is bigger than in households.Abstract: Cockroach (Periplaneta americana) is one of the vectors in the environment that can transmit disease. Cockroaches can act as potential mechanical vectors of antibiotic resistant bacteria. Enterobacteriaceae is a gram-negative bacteria that has natural habitats in the digestive tract of humans and animals. Enterobacteriaceae that produce Extended Spectrum β-lactamases (ESBLs) have emerged as major pathogens in hospitals. The study analyzed the prevalence of ESBL producing bacteria in cockroaches that lived in hospitals and residential homes. In this study, a total of 200 cockroaches consisting of 100 cockroaches from the hospital environment and 100 cockroaches from the residential environment were analyzed bacteriologically for colonization of ESBL producing Enterobacteriaceae. The specimen of the alimentary tract was taken and sub-cultured in MacConkey agar supplemented with cefotaxime 2 ug/ml. Growth colonies were suggested as an ESBL-producing bacteria, then were confirmed as ESBL producers by the Double Disk Synergy Test (DDST). The ESBL gene was detected by Polymerase Chain Reaction (PCR). Among 100 household cockroach samples, 14 (14%) were identified as ESBL producers, while 100 hospital cockroaches were 26 (26%) positive ESBL. The ESBL gene, in hospital cockroach were identified of CTXM 19 (19%), SHV 7 (7%), and not any TEM gene, while among household cockroaches were identified CTXM 2 (2%), SHV 11 (11%), and also not detected TEM ESBL gene. Among ESBL genes, only the CTXM gene was significantly different between household and hospital cockroaches.

Deltamethrin contact exposure mediated toxicity and histopathological aberrations in tissue systems of cockroach species Periplaneta americana and Blatella germanica

Cockroach species Periplaneta americana and Blatella germanica potentially survive in locations close to human activity. Besides spoiling food material, cockroaches also transfer pathogens of different diseases among human. Since the insecticides have been used extensively to control cockroaches, information on their insecticide susceptibility and toxicity at cellular level may be crucial. In the study, deltamethrin toxicity as well as the deltamethrin-mediated cytomorphological changes in brain, ovary and midgut of the two important cockroach species has been assessed. Different concentrations [0.00025% (0.0025mg/ml), 0.0025% (0.025mg/ml), 0.025 (0.25mg/ml), 0.25% (2.5mg/ml), 0.5% (5mg/ml), 1% (10mg/ml)] of deltamethrin in acetone were used to expose test species in WHO bottle assay. Knockdown was recorded after 5 min interval while delayed mortality was observed after 24 hr. Brain, ovary and gut were dissected post 1 hr exposure and 24 hr holding (for 0.25%, 0.5% and 1% concentration), and tissues were processed for microscopic analysis. Deltamethrin exposed cockroaches and dissected tissues were used to estimate deltamethrin using HPLC. At 0.00025% (lowest concentration), the percentage knock-down observed was 66.7% for P. americana and 80% B. germanica respectively (R2= 0.78; p=0.0001) in 1 hr. KDT50 value was found to be 8.7 min (95% CI: 7.3-10.2), while KDT99 was 20.7 min (95% CI: 16.0-35.7) in P. americana at 1% concentration. Whereas, the KDT50 and KDT99 values for B. germanica were 7.4 min (95% CI: 5.4-9.1) and 27.4 min (95% CI: 18.2-80.0) at similar concentration. LD50 and LD95 values (for 60 min standard exposure) were 0.0006 % (95% CI: 0.00-0.001) and 0.034% (95% CI: 0.013-0.49) respectively for P. americana, while these values were 0.0005 (95% CI: 0.00-0.001) and 0.04 (95% CI: 0.01-0.23) for B. germanica. Exposure to 1% deltamethrin induced considerable toxic effect in the epithelial cells in the midgut. HPLC estimated 0.21±0.05 mg (95% CI - 0.18-0.25; CoV 23.9%) deltamethrin in P. americana post 1% exposure. Even short term exposure of low concentration of synthetic pyrethroid deltamethrin displayed immediate knockdown and delayed mortality in both the test species. Considerable histological damage was observed in both the insects at 1% exposure. In India, resistance to deltamethrin may have been reported among different insects due its extensive use, however the formulations such as insecticide paints, attractant baits etc. developed using deltamethrin as active ingredient could be useful in cockroach control operations.