Anti-bacterial activity and brine shrimp lethality bioassay of methanolic extracts of fourteen different edible vegetables from Bangladesh

Objective:To investigate the antibacterial and cytotoxic activity of fourteen different edible vegetables methanolic extract from Bangladesh.Methods:The antibacterial activity was evaluated using disc diffusion assay method against 12 bacteria(both gram positive and gram negative).The plant extracts were also screened for cytotoxic activity using the brine shrimp lethality bioassay method and the lethal concentrations(LC_(50))were determined at confidence intervals by analyzing the data on a computer loaded with"Finney Programme??Results:All the vegetable extracts showed low to elevated levels of antibacterial activity against most of the tested strains(zone of inhibition=5-28 mm).The most active extract against all bacterial strains was from Xanthium indicum which showed remarkable antibacterial activity having the diameter of growth inhibition zone ranging from 12 to 28 mm followed by Alternanthera sessilis(zone of inhibition=6-21 mm).All extracts exhibited considerable general toxicity towards brine shrimps.The LC_(50)value of the tested extracts was within the range of 8.447 to 60.323μg/mL with respect to the positive control(vincristine sulphate)which was 0.91μg/mL.Among all studied extracts,Xanthium indicum displayed the highest cytotoxic effect with LC_(50)value of 8.447μg/mL.Conclusions:The results of the present investigation suggest that most of the studied plants are potentially good source of antibacterial and anticancer agents.

The acute lethality and endocrine effect of 1,2,3,7,8-PeCDD in juvenile goldfish (Carassius auratus) in vivo

1,2,3,7,8-PeCDD was administrated to juvenile goldfish （Carassius auratus） by peritoneal injections to explore the acute lethality and endocrine effects of 1,2,3,7,8-PeCDD in vivo. The value of acute median lethal dosage （LD50） of 1,2,3,7,8-PeCDD was determined in acute lethality tests. The endocrine effect of 1,2,3,7,8-PeCDD, whose exposed concentrations were determined based on the LD50 （1.84 mg/kg）, was studied by measuring the plasma vitellogenin （Vtg） content in juvenile male goldfish with enzyme-linked immunosorbent assays （ELISA）. Due to its significant induction of the plasma Vtg after one week＇s exposure in vivo in the 1/2 LD50 and LD30 groups, 1,2,3,7,8-PeCDD might be one of the important contributors to the estrogenic effect of PCDDs in the environment. The values of 1/2 LD50 and LD30 were within the range of the effective dosages of 1,2,3,7,8-PeCDD, indicating that there was a certain relationship between the estrogenic effective dosages and the LD50.

DNA repair and synthetic lethality

Tumors often have DNA repair defects, suggesting additional inhibition of other DNA repair pathways in tumors may lead to synthetic lethality. Accumulating data demonstrate that DNA repair-defective tumors, in particular homologous recombination （HR）, are highly sensitive to DNA-damaging agents. Thus, HR-defective tumors exhibit potential vulnerability to the synthetic lethality approach, which may lead to new therapeutic strategies. It is well known that poly （adenosine diphosphate （ADP）-ribose） polymerase （PARP） inhibitors show the synthetically lethal effect in tumors defective in BRCA1 or BRCA2 genes encoded proteins that are required for efficient HR. In this review, we summarize the strategies of targeting DNA repair pathways and other DNA metabolic functions to cause synthetic lethality in HR-defective tumor cells.

Progression of Frequency and Lethality of Severe Malaria from 2017 to 2020 in the Pediatric Unit of CHUD-Parakou (Benin)

Background: The latest WHO report shows a decline in the performances achieved concerning the fight against malaria since 2017. This research work aimed to investigate the progression of frequency and lethality due to severe malaria from 2017 to 2020 in the pediatric unit of the Borgou University Teaching Hospital in Parakou (CHUD-Parakou). Patients and Methods: This research work is a descriptive and analytical case-control study focused on all the children aged 1 month and more, hospitalized in the pediatric unit of CHUD-Parakou from January 1, 2017, to December 31, 2020. Recruitment criteria were the following: be admitted to hospital during the period specified above;have a usable medical record containing the diagnosis and type of discharge, and the findings of thick smear examination and/or of a rapid diagnostic test. Sampling was complete and takes into account all the medical records of children meeting the inclusion criteria. Epi Info 7.2.2 was the software used to perform data processing. Results: The frequencies of severe malaria in the unit were estimated at 19.89%, 22.65%, 29.65% and 27.51% respectively in 2017, 2018, 2019 and 2020. Lethality rates varied from 7.76% to 8.68 from 2017 through 2020. The death risk associated with severe malaria was 3.08 times higher in children suffering from severe acute undernutrition. Conclusion: Despite all the efforts made by the health authorities and the technical and financial partners, the frequency and lethality of severe malaria are increasing in the pediatric unit of the B/A Regional University Teaching Hospital (CHUD-B/A). It is therefore worth investigating the determinants of this situation.

Synthetic Lethality Induced by a Strong <i>Drosophila</i>Enhancer of Expanded Polyglutamine Tract

Proteins containing an expanded polyglutamine tract are neurotoxins. The expanded polyglutamine proteins influence a variety of cellular functions. In Drosophila the GMR-Gal4/UAS expression system has been widely used in an eye-based model to study human neurodegenerative diseases. This system has facilitated the isolation and characterization of abundant Drosophilagenes that interact with the expanded polyglutamine proteins. We used the GMR-Gal4/UAS system to express three proteins containing an expanded polyglutamine tract, or an expanded polyglutamine tract alone. Doubling the dose of these proteins resulted in pupal lethality, indicating that these toxic proteins induced a sensitized condition that is prone to synthetic lethality. By using the GMR-Gal4/UAS system, we showed that a Drosophilagene interacts with three expanded polyglutamine proteins to induce a synthetic lethal phenotype. We further demonstrated that the synthetic lethality was mediated through the toxic expanded polyglutamine tract. Our study raises a possibility that conventional genetic screens may not recover synthetic lethal alleles, which are presumably stronger interacting alleles than the currently known modifiers of an expanded polyglutamine tract, due to synthetic lethality.

Synthetic Lethality Induced by Toxic Polyglutamine Tract II: A Survey in Drosophila

Mutant proteins containing an expanded polyglutamine tract induce cell death and cause neurodegenerative diseases. These toxic proteins interfere with a variety of physiological pathways, but the key interactions between the toxins and cellular factors remain unclear. To model the diseases in Drosophila, the GMR-Gal4/UAS gene expression system has been used extensively, which operates in the eyes. By using the system, genome-wide studies have resulted in the isolation of functionally diverse groups of Drosophila genes that interact with the disease proteins. We previously reported that coexpressing the Drosophila Dikar gene and an expanded polyglutamine tract by GMR-Gal4/UAS induced a synthetic lethality. We carried out follow-up experiments to isolate additional synthetic lethal alleles. Our data provide evidence that synthetic lethality associated with expressing an expanded polyglutamine tract is more common than thought to be and could have escaped the conventional genetic screens. Our results also suggest that 1) the gene expression system is leaky, allowing expression outside of the primary target eye cell types;2) expressing an expanded polyglutamine tract is extremely toxic to cells;and 3) combining the leaky expression and the toxicity results in a lethal-prone condition. Thus, genetic modifications to the disease proteins’ acute toxicity could frequently lead to synthetic lethality. However, synthetic lethal alleles are excluded from most conventional screens, necessitating alternative approaches such as a two-step method used in this study to isolate the modifiers. Since synthetic lethality reflects essential genetic buffering networks, studying these alleles may hold the keys to identify the critical interactions in the disease development between the toxic proteins and the physiological pathways.

Enhancing the stability and ecological safety of mass-reared transgenic strains for field release by redundant conditional lethality systems

The genetic manipulation of agriculturally important insects now allows the development of genetic sexing and male sterility systems for more highly efficient biologically-based population control programs, most notably the Sterile Insect Technique （SIT）, for both plant and animal insect pests. Tetracycline-suppressible （Tet-off） conditional lethal systems may function together so that transgenic strains will be viable and fertile on a tetracycline-containing diet, but female-lethal and male sterile in tetracycline-free condi- tions. This would allow their most efficacious use in a unified system for sterile male-only production for SIT. A critical consideration for the field release of such transgenic insect strains, however, is a determination of the frequency and genetic basis of lethality revertant survival. This will provide knowledge essential to evaluating the genetic stability of the lethality system, its environmental safety, and provide the basis for modifications ensur- ing optimal efficacy. For Tet-off lethal survival determinations, development of large-scale screening protocols should also allow the testing of these modifications, and test the ability of other conditional lethal systems to fully suppress propagation of rare Tet-off survivors. If a dominant temperature sensitive （DTS） pupal lethality system proves efficient for sec- ondary lethality in Drosophila, it may provide the safeguard needed to support the release of sexing/sterility strains, and potentially, the release of unisex lethality strains as a form of genetic male sterility. Should the DTS Prosβ21 mutation prove effective for redundant lethality, its high level of structural and functional conservation should allow host-specific cognates to be created for a wide range of insect species.

Epigenetic silencing schlafen-11 sensitizes esophageal cancer to ATM inhibitor

BACKGROUND Targeting DNA damage response(DDR)pathway is a cutting-edge strategy.It has been reported that Schlafen-11(SLFN11)contributes to increase chemosensitivity by participating in DDR.However,the detailed mechanism is unclear.AIM To investigate the role of SLFN11 in DDR and the application of synthetic lethal in esophageal cancer with SLFN11 defects.METHODS To reach the purpose,eight esophageal squamous carcinoma cell lines,142 esophageal dysplasia(ED)and 1007 primary esophageal squamous cell carcinoma(ESCC)samples and various techniques were utilized,including methylationspecific polymerase chain reaction,CRISPR/Cas9 technique,Western blot,colony formation assay,and xenograft mouse model.RESULTS Methylation of SLFN11 was exhibited in 9.15%of(13/142)ED and 25.62%of primary(258/1007)ESCC cases,and its expression was regulated by promoter region methylation.SLFN11 methylation was significantly associated with tumor differentiation and tumor size(both P<0.05).However,no significant associations were observed between promoter region methylation and age,gender,smoking,alcohol consumption,TNM stage,or lymph node metastasis.Utilizing DNA damaged model induced by low dose cisplatin,SLFN11 was found to activate non-homologous end-joining and ATR/CHK1 signaling pathways,while inhibiting the ATM/CHK2 signaling pathway.Epigenetic silencing of SLFN11 was found to sensitize the ESCC cells to ATM inhibitor(AZD0156),both in vitro and in vivo.CONCLUSION SLFN11 is frequently methylated in human ESCC.Methylation of SLFN11 is sensitive marker of ATM inhibitor in ESCC.

Retro Placental Hematoma: Maternal and Fetal Prognosis at the Maternity of the University Hospital of Bouake

Introduction: Retroplacental haematoma (RPH) is a very serious complication of pregnancy, with life-threatening consequences for both the mother and foetus. The aim of this study is to determine the incidence and epidemiological characteristics of patients with retroplacental haematoma (RPH) and describe the maternal-foetal complications at Bouaké University Hospital. Methods: This was a cross-sectional prospective, descriptive and analytical study carried out at Bouaké University Hospital over a period of 3 years, from January 1, 2019 to December 31, 2021. All parturients with RPH whose delivery took place at the hospital were included in the study. Data were entered and analysed using EPI INFO software version 7.2.2.6. Results: We recorded 2,0959 deliveries, including 202 cases of RPH, representing an incidence of 0.96%. The 21 to 35 age group accounted for 64.4%, multigestas and large multigestas accounted for 58.5% and multiparas accounted for 41.6%. The main signs on clinical examination were metrorrhagia (100%), arterial hypertension (84.6%) and cervical cerclage (79.7%). Preeclampsia accounted for 50% of per-gestational pathologies. Maternal mortality was 12.9%. Morbidity was dominated by anaemia in 64.1%, followed by disseminated intravascular coagulation (DIC) in 21.8%, and the factors associated with this maternal prognosis were multiple gestations, multiparity, Sher grade IIIb and the occurrence of complications such as DIC, shock, renal complications and HELLP syndrome. Neonatal mortality was 79.2%, and the factors associated with these fetal prognoses were cup size ≥ 5 cm and hematoma weight ≥ 500 g. Conclusion: Better screening of at-risk populations, early diagnosis and treatment in an organised and equipped medical and surgical facility would improve prognosis.

Cyclin-dependent kinases-based synthetic lethality: Evidence, concept, and strategy

Synthetic lethality is a proven effective antitumor strategy that has attracted great attention.Large-scale screening has revealed many synthetic lethal genetic phenotypes,and relevant smallmolecule drugs have also been implemented in clinical practice.Increasing evidence suggests that CDKs,constituting a kinase family predominantly involved in cell cycle control,are synthetic lethal factors when combined with certain oncogenes,such as MFC,TP53,and RAS,which facilitate numerous antitumor treatment options based on CDK-related synthetic lethality.In this review,we focus on the synthetic lethal phenotype and mechanism related to CDKs and summarize the preclinical and clinical discoveries of CDK inhibitors to explore the prospect of CDK inhibitors as antitumor compounds for strategic synthesis lethality in the future.

Targeting“undruggable”c-Myc protein by synthetic lethality

Synthetic lethal screening,which exploits the combination of mutations that result in cell death,is a promising method for identifying novel drug targets.This method provides a new avenue for targeting Uundruggable,9 proteins,such as c-Myc.Here,we revisit current methods used to target c-Myc and discuss the important functional nodes related to c-Myc in non-oncogene addicted network,whose inhibition may cause a catastrophe for tumor cell destiny but not for normal cells.We further discuss strategies to identify these functional nodes in the context of synthetic lethality.We review the progress and shortcomings of this research field and look forward to opportunities offered by synthetic lethal screening to treat tumors potently.

Water as a Standard Substance of a Logarithmic Poison Scale

The lethal dose LD50 represents the most important experimental value for acute toxicity. The simple logarithmic calculation of -log10 LD50 = value leads to the possible poison power pLD. As with the pH or pK value, respectively, for acid or the scale of earthquake intensities the logarithm helps making large differences of orders of magnitude easier to understand since they are more comparable. The higher the pLD value, the higher is the power of poison. An increase of the pLD value by 1 stands for a tenfold increase in toxicity. The lethal acute dose for water, one of the most important and at the same time non-toxic substances of all, is about one tenth of the body weight. This leads to a possible pLD value for water of 1, an ideal starting value for a logarithmic poison scale.

Antimicrobial,antityrosinase and brine shrimp lethality test of Bauhinia rufescens Lam(Fabaceae)

Objective:To evaluate leaves and stem bark extracts of Bauhinia rufescens for antimicrobial activities,tyrosinase enzyme inhibition potentials and lethality to brine shrimp larvae(Artemiasalina).Methods:The plant materials were extracted based on polarity gradient of petroleum ether,ethyl acetate and methanol.The extracts were investigated for their antimicrobial,antityrosinase and cytotoxicity potentials.Results:The antimicrobial results indicated that the extracts inhibited the microbial growth in the range of 6.00-12.57 mm(450-1800μg/mL)for bacterial strains and 7.33-14.03 mm(225-1800μg/mL)for fungal strains.While the tyrosinase enzyme inhibition assay of the extracts showed that both the petroleum ether leaves and stem bark extracts exhibited a moderate inhibition(39.60%and 39.89%)towards the action of mushroom tyrosinase enzyme on L-DOPA.In the brine shrimp lethality assay,ethyl acetate and methanol extracts of the leaves of the plant were found toxic to the Artemia salina with IC_(50)values of 0.059 mg/mL and 0.389 mg/mL.However,both the petroleum ether and ethyl acetate extracts of the stem bark were nontoxic to the larvae.Conclusions:The result of the present study suggest the presence of phytochemicals possessing antimicrobial and antityrosinase activity as well as cytotoxic agents.

Studies on antimicrobial activity and brine shrimp lethality of crude samples of six different species of puffer ifshes

Objective:To evaluate the antimicrobial activity and brine shrimp lethality activity of six different species of puffer fishes,includingCyclichthys orbicularis,Diodon holocanthus,Canthigaster solandri,Arthron hispidus,A.inermis andLagocephalua inermis(L.inermis).Methodology:The puffer fishes were collected from Annangkovil Fish Landing Centre(Lattitude 11°30.47'N;Longitude 79°47.02'E),Parangipettai,Southeast Coast of India during summer season because of availability.Fresh tissue samples were collected from the clearly washed specimens,extracted with methanol at 37°C for 3 days and filtered through Whatman No.1 filter paper.The solvents such as methanol and ethanol were concentrated by using rotary evaporator under reduced pressure.The dark brown gummy mass was stored at 4°C for further analysis.Prepared crude samples were analysed with human pathogens to assess the antibacterial activity and this was carried out by using standard disc diffusion method.The brine shrimp lethality was calculated as the percentage of mortality which was firstly calculated by dividing the number of dead larvae by the total number and then multiplied to 100%.Results:The antibacterial activity of crude extract of puffer fishes were exhibited against 10 different human bacterial pathogens.Among the ten human pathogens,Arthron hispidus showed maximum zone of inhibition(8 mm)againstStaphylococcus aureus whileL.inermis showed minimum activity(1 mm)againstProteus mirabilis and no zone of inhibition was observed againstStaphylococcus aureus.Brine shrimp lethality was examined with six puffer fish extracts.Cyclichthys orbicularis showed maximum mortalities as 100%andL.inermis showed minimum mortalities as 70%at a concentration of 500μg/mL.Conclusion:In conclusion,the study showed the preliminary investigation of crude extracts of puffer fishes about the prominent activity against human bacterial pathogens.The extracts had a good cytotoxic potential against brine shrimpArtemina salina.

Phytochemical and toxicity evaluation of Phaleria macrocarpa(Scheff.)Boerl by MCF-7 cell line and brine shrimp lethality bioassay

Objective:To evaluate the cytotoxicity of Phaleria macrocarpa fruits extracts.Methods:The cytotoxicity test was carried out by in vitro MCF-7 cell line and in vivo brine shrimp lethality bioassay.Results:The preliminary phytochemical test showed the presence of alkaloids,carbohydrate,glycosides,saponin,terpene,steroids,phenols and flavonoids.The MTT-assay results showed that the highest percentage of cell viability was 106.23%at concentration of 1.25μL and the lowest percentage was 13.04%at concentration of 10μL.Conclusions:The MTT-assay and brine shrimp lethality bioassay results showed that the extract was non-toxic and it would be consumable as a herbal remedy.

Effects of total dissolved gas supersaturated water on lethality and catalase activity of Chinese sucker(Myxocyprinus asiaticus Bleeker)

Total dissolved gas(TDG) supersaturation caused by dam sluicing can result in gas bubble trauma(GBT) in fish and threaten their survival.In the present study,Chinese suckers(Myxocyprinus asiaticus Bleeker) were exposed to TDG supersaturated water at levels ranging from 120% to 145% for 48 h.The median lethal concentration(LC 50) and the median lethal time(LT 50) were determined to evaluate acute lethal effects on Chinese suckers.The results showed that the LC 50 values of 4,6,8,and 10 h were 142%,137%,135%,and 130%,respectively.The LT 50 values were 3.2,4.7,7.8,9.2,and 43.4 h,respectively,when TDG supersaturated levels were 145%,140%,135%,130%,and 125%.Furthermore,the biological responses in Chinese suckers were studied by assaying the catalase(CAT) activities in gills and muscles at the supersaturation level of 140% within LT 50.The CAT activities in the gills and muscle tissues exhibited a regularity of a decrease after an increase.CAT activities in the muscles were increased significantly at 3/5LT 50(P<0.05) and then came back to the normal level.However,there were no significant differences between the treatment group(TDG level of 140%) and the control group(TDG level of 100%) on CAT activities in the gills before 3/5LT 50(P>0.05),but the activities were significantly lower than the normal level at 4/5LT 50 and LT 50(P<0.05).

CRISPR/Cas9-mediated Tyrosine hydroxylase knockout resulting in larval lethality in Agrotis ipsilon

Tyrosine hydroxylase (TH)is involved in insect melanin and the catecholamine biosynthesis pathway.TH as an enzyme catalyzing the conversion of tyrosine to 3,4- dihydroxyphenylalanine is the first step reaction in the pathway.Although TH has been proven to affect the pigmentation of the epidermis and development in many insects,there is no report about physiological function of the THgene inAgrotis ipsilon.Here we cloned the TH gene from A.ipsilon.Semi-quantitative real-time polymerase chain reaction (PCR) analysis showed that AiTH was expressed at all development stages.Moreover,its high expression levels in the head and epidermis suggest that it is mainly related to pigment deposition and insect development.Then,we used the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9system to target the AiTH gene:deletion events were detected at the target sites.Compared with the control group,a few mutants with the phenomenon of narrowing in the egg shell and embryos can develop but cannot hatch;the other hatched embryos were seriously dehydrated after hatching and died within the first day.Quantitative real-time PCR analysis revealed that THwas down-regulated inAiTHmutants.Here,our work demonstrated thatAiTHplays an important role in growth and development of newly hatched larvae;meanwhile,it would be a promising target to explore a control strategy for A.ipsilon.

Estimation of cytotoxic potency by brine shrimp lethality bioassay application of Clerodendrum infortunatum Linn.

Objective:To learn a scientific and systematic knowledge of anticancer,antimicrobial and pharmacological activities of natural products and estimate cytotoxic potency by using ethanol and chloroform extracts of root,leaf and stem of Clerodendrum infortunatum(Verbenaceae)due to its random use in customary and traditional medicine to cure common ailments such as intestinal disorder,diarrhea,tuberculosis and respiratory problems etc.Methods:The in vitro application was carried out with the bench-top bioassay method by using brine shrimp lethality bioassay.Results:All of the crude extracts were found to be lethal and effective.The LC50 value of ethyl alcohol fraction of root was 20.845 mg/L compared to the standard drug tetracycline of 14.675 mg/L to brine shrimp nauplii,indicating that the extracts were biologically active.Conclusions:The cytotoxic study of LC50 value showed that a good correlation with the antibiotic tetracycline.From the comparative correlation error bars and percentage,we understood that ethyl alcohol fraction of root extract was very effective.This study serves as a basis for further research to lead compounds to be isolated so that it may be as a template for the implications of these results for bioactivity and drug discovery potential of herbal products.

A peptide chain release factor 2a gene regulates maize kernel development by modulating mitochondrial function

Mitochondrial protein translation that is essential for aerobic energy production includes four essential steps of the mitochondrial ribosome cycle,namely,initiation,elongation,termination of the polypeptide,and ribosome recycling.Translation termination initiates when a stop codon enters the A site of the mitochondrial ribosome where it is recognized by a dedicated peptide release factor(RF).However,RFs and mechanisms involved in translation in plant mitochondria,especially in monocotyledons,remain largely unknown.Here,we identified a crumpled kernel(crk5 allele)mutant,with significantly decreased kernel size,100-kernel weight,and an embryo-lethal phenotype.The Crk5 allele was isolated using map-based cloning and found to encode a mitochondrial localization RF2a.As it is an ortholog of Arabidopsis mitochondrial RF2a,we named the gene ZmmtRF2a.ZmmtRF2a is missing the 5th–7th exons in the crk5 resulting in deletion of domains containing motifs GGQ and SPF that are essential for release activity of RF,mitochondrial ribosome binding,and stop codon recognition.Western blot and qRT-PCR analyses indicate that the crk5 mutation results in abnormal mitochondrion structure and function.Intriguingly,we observed a feedback loop in the crk5 with up-regulated transcript levels detected for several mitochondrial ribosome and mitochondrial-related components,in particular mitochondrial complexes CI,CIV,and a ribosome assembly related PPR.Together,our data support a crucial role for ZmmtRF2a in regulation of mitochondrial structure and function in maize.