Identification of odorant-binding proteins and functional analysis of antenna-specific BhorOBP28 in Batocera horsfieldi (Hope).

BACKGROUND: The important wood-boring pest Batocera horsfieldi has evolved a sensitive olfactory system to locate host plants. Odorant-binding proteins (OBPs) are thought to play key roles in olfactory recognition. Therefore, exploring the physiological function of OBPs could facilitate a better understanding of insect chemical communications. RESULTS: In this research, 36 BhorOBPs genes were identified via transcriptome sequencing of adults' antennae from B. horsfieldi, and most BhorOBPs were predominantly expressed in chemosensory body parts. Through fluorescence competitive binding and fluorescence quenching assays, the antenna-specific BhorOBP28 was investigated and displayed strong binding affinities forming stable complexes with five volatiles, including (+)-α-Pinene, (+)-Limonene, ß-Pinene, (-)-Limonene, and (+)-Longifolene, which could also elicit conformation changes when they were interacting with BhorOBP28. Batocera horsfieldi females exhibited a preference for (-)-Limonene, and a repellent response to (+)-Longifolene. Feeding dsOBP19 produced by a bacteria-expressed system with a newly constructed vector could lead to the knockdown of BhorOBP28, and could further impair B. horsfieldi attraction to (-)-Limonene and repellent activity of (+)-Longifolene. The analysis of site-directed mutagenesis revealed that Leu7, Leu72, and Phe121 play a vital role in selectively binding properties of BhorOBP28. CONCLUSION: By modeling the molecular mechanism of olfactory recognition, these results demonstrate that BhorOBP28 is involved in the chemoreception of B. horsfieldi. The bacterial-expressed dsRNA delivery system gains new insights into potential population management strategies. Through the olfactory process concluded that discovering novel behavioral regulation and environmentally friendly control options for B. horsfieldi in the future. © 2024 Society of Chemical Industry.

Mealybug salivary microbes inhibit induced plant defenses.

BACKGROUND: Phenacoccus solenopsis is a polyphagous invasive mealybug that caused serious damage to crops worldwide. Phloem-sucking hemipterans are known to carry symbiotic microbes in their saliva. However, the role of salivary bacteria of P. solenopsis in modulating plant defenses remains limited. Exploring the impact of salivary bacteria on plant defense responses will contribute to the development of new targets for efficient control of invasive mealybugs. RESULTS: Salivary bacteria of the invasive mealybug P. solenopsis can suppress herbivore-induced plant defenses and thus enhance mealybug fitness. Mealybugs treated with an antibiotic showed decreased weight gain, fecundity and survival. Untreated mealybugs suppressed jasmonic acid (JA)-regulated defenses but activated salicylic acid (SA)-regulated defenses in cotton plants. In contrast, antibiotic-treated mealybugs triggered JA-responsive gene expression and JA accumulation, and showed shortened phloem ingestion. Reinoculating antibiotic-treated mealybugs with Enterobacteriaceae or Stenotrophomonas cultivated from mealybug saliva promoted phloem ingestion and fecundity, and restored the ability of mealybugs to suppress plant defenses. Fluorescence in situ hybridization visualization revealed that Enterobacteriaceae and Stenotrophomonas colonize salivary glands and are secreted into the mesophyll cells and phloem vessels. Exogenous application of the bacterial isolates to plant leaves inhibited JA-responsive gene expression and activated SA-responsive gene expression. CONCLUSION: Our findings imply that symbiotic bacteria in the saliva of the mealybug play an important role in manipulating herbivore-induced plant defenses, enabling this important pest to evade induced plant defenses and promoting its performance and destructive effects on crops. © 2023 Society of Chemical Industry.

Predicted structure of odorant-binding protein 12 from Monochamus alternatus (Hope) suggests a mechanism of flexible odorant-binding.

Odorant-binding proteins (OBPs) are thought to bind and deliver hydrophobic odorants from the environment to receptors on insect sensory neurons, and have been used to screen behaviorally active compounds of insects. In order to screen behaviorally active compounds for Monochamus alternatus by OBPs, we cloned full length of Obp12 coding sequence from M. alternatus and proved secretion property of MaltOBP12, then tested binding affinities of recombinant MaltOBP12 to 12 pine volatiles in vitro. We confirmed MaltOBP12 has binding affinities to 9 pine volatiles. The structure of MaltOBP12 and protein-ligand interactions were further analyzed by homology modeling, molecular docking, site-directed mutagenesis, and ligand-binding assays. These results demonstrated that the binding pocket of MaltOBP12 consists of several large aromatic and hydrophobic residues, and four aromatic residues (Tyr50, Phe109, Tyr112, Phe122) are essential for odorant-binding; ligands adopt extensive hydrophobic interactions with an overlapping subset of residues in the binding pocket. Finally, based on non-directional hydrophobic interactions, MaltOBP12 binds odorants flexibly. These findings will not only help us understand how OBPs flexibly bind odorants but also promote to screen of behaviourally active compounds by computer methods to prevent M. alternatus in the future.

Homeotic Protein Distal-Less Regulates NlObp8 and NlCsp10 to Impact the Recognition of Linalool in the Brown Planthopper Nilaparvata lugens.

Odorant-binding proteins (OBPs) and chemosensory proteins (CSPs), which are thought to play key roles in the olfactory recognition of insects, can be induced by the odorants they recognize, but little is known about the underlying regulatory mechanisms. Here, we found that NlOBP8 and NlCSP10 play coordinative roles in the chemoreception of brown planthoppers (BPHs) to the volatile component linalool. Also, the relative mRNA levels of NlObp8 and NlCp10 decreased upon exposure to linalool. Further, homeotic protein distal-less (Dll), which was also highly expressed in the antennae, was found to positively regulate the transcription of NlObp8 and NlCsp10 directly. Knocking down NlDll expression downregulated the expression of many additional olfactory functional genes and impaired the repellent behavior of BPHs to linalool. Our findings elucidate the direct regulatory role of Dll in BPHs' olfactory plasticity to linalool through modulating the olfactory functional gene expression and could provide guidance to sustainably control BPHs in the field.

A Highly Expressed Antennae Odorant-Binding Protein Involved in Recognition of Herbivore-Induced Plant Volatiles in Dastarcus helophoroides.

Natural enemies such as parasitoids and parasites depend on sensitive olfactory to search for their specific hosts. Herbivore-induced plant volatiles (HIPVs) are vital components in providing host information for many natural enemies of herbivores. However, the olfactory-related proteins involved in the recognition of HIPVs are rarely reported. In this study, we established an exhaustive tissue and developmental expression profile of odorant-binding proteins (OBPs) from Dastarcus helophoroides, an essential natural enemy in the forestry ecosystem. Twenty DhelOBPs displayed various expression patterns in different organs and adult physiological states, suggesting a potential involvement in olfactory perception. In silico AlphaFold2-based modeling and molecular docking showed similar binding energies between six DhelOBPs (DhelOBP4, 5, 6, 14, 18, and 20) and HIPVs from Pinus massoniana. While in vitro fluorescence competitive binding assays showed only recombinant DhelOBP4, the most highly expressed in the antennae of emerging adults could bind to HIPVs with high binding affinities. RNAi-mediated behavioral assays indicated that DhelOBP4 was an essential functional protein for D. helophoroides adults recognizing two behaviorally attractive substances: p-cymene and γ-terpinene. Further binding conformation analyses revealed that Phe 54, Val 56, and Phe 71 might be the key binding sites for DhelOBP4 interacting with HIPVs. In conclusion, our results provide an essential molecular basis for the olfactory perception of D. helophoroides and reliable evidence for recognizing the HIPVs of natural enemies from insect OBPs' perspective.

Volatile-mediated tritrophic defense and priming in neighboring maize against Ostrinia furnacalis and Mythimna separata.

BACKGROUND: Plants respond to attackers by triggering phytohormones signaling associated metabolites, including herbivore-induced plant volatiles (HIPVs). HIPVs can indirectly act against herbivory by recruitment of natural enemies and priming of neighboring plants. Ostrinia furnacalis and Mythimna separata are important insect herbivores of maize plants that have a devastating influence on yield. However, little is known about how maize temporally reconfigures its defense systems against these herbivores and variation of neighboring plant resistance. RESULTS: This study investigated the effects of HIPVs on the behavior of the dominant predatory beetle Harmonia axyridis and priming in neighboring maize defense against O. furnacalis and M. separata over time. The results showed that maize damaged by either O. furnacalis or M. separata enhanced the release of volatiles including terpenes, aldehydes, alkanes and an ester, which elicited an increased attractive response to H. axyridis after 3 and 12 h, respectively. O. furnacalis damage resulted in accumulations of leaf jasmonic acid (JA) and salicylic acid in maize after 6 and 3 h, respectively, while M. separata damage only raised the JA level after 3 h. Furthermore, HIPVs were able to prime neighboring plants through the accumulation of JA after 24 h. Both larvae showed a significant decrease in weight accumulation after 48 h of feeding on the third leaves of the primed plant. CONCLUSION: Taken together, the findings provide a dynamic overview of how attacked maize reconfigures its volatiles and phytohormones to defend against herbivores, as well as priming of neighboring plants against oncoming attacks. © 2022 Society of Chemical Industry.

NlugOBP8 in Nilaparvata lugens Involved in the Perception of Two Terpenoid Compounds from Rice Plant.

Odorant binding proteins (OBPs) play an important role in insect peripheral olfactory systems and exploring the physiological function of OBPs could facilitate the understanding of insects' chemical communication. Here, the functional analysis of an antenna-based NlugOBP8 from brown planthopper (BPH) Nilaparvata lugens (Stål) was performed both in vitro and in vivo. Recombinant NlugOBP8 exhibited strong binding affinity to 13 out of 26 rice plant volatiles and could form a stable complex with 9 of them according to the fluorescence binding and fluorescence quenching experiments. Circular dichroism spectra demonstrated that six volatiles could give rise to significant conformational change of recombinant NlugOBP8. H-tube olfactometer bioassay confirmed that BPHs were significantly attracted by nerolidol and significantly repelled by linalool, caryophyllene oxide, and terpinolene, respectively. Antennae of dsNlugOBP8-injected BPHs exhibited significantly lower electrophysiological response to linalool and caryophyllene oxide. Moreover, the repellent responses of BPHs to these two volatiles were also impaired upon silencing NlugOBP8. These data suggest that NlugOBP8 is involved in recognizing linalool and caryophyllene oxide and provide additional target for the sustainable control of BPHs.

Sublethal Exposure to Cadmium Induces Chemosensory Dysfunction in Fire Ants.

Ants easily accumulate cadmium (Cd) from the food web in terrestrial ecosystems. Cd contamination may cause olfactory dysfunction and consequently disorders in the social behavior of ants. To explore the molecular mechanism underlying the effect of Cd exposure on the chemosensory process of ants, we characterized the Cd-induced variations in the expression of genes involved in chemoreception and electrophysiological and behavioral sensitivity to semiochemicals by using the red imported fire ant, Solenopsis invicta, as a model system. As a result, Cd exposure increased Cd accumulation and decreased the survival rate of S. invicta. Cd exposure altered the expression profiles of odor binding protein genes of S. invicta (SiOBPs). Specifically, SiOBP15 protein expression was upregulated upon Cd exposure. Both SiOBP7 and SiOBP15 exhibited high binding affinities to limonene, nonanal, and 2,4,6-trimethylpyridine. S. invicta exposed to Cd showed less sensitive electrophysiological and behavioral response to the three chemicals but exhibited sensitive perception to undecane. Silencing of SiOBP7 and SiOBP15 abolished the behavioral response of S. invicta to nonanal and undecane, respectively, suggesting that SiOBP7 and SiOBP15 play essential roles in the chemoreception of S. invicta. In general, our results suggest that Cd contamination may interfere with olfactory signal transduction by altering the expression of SiOBPs, consequently evoking chemosensory dysfunction in fire ants.

Silencing of an odorant binding protein (SaveOBP10) involved in the behavioural shift of the wheat aphid Sitobion avenae (Fabricius).

Insects are highly reliant on their active olfactory system in which odorant binding proteins play a role to selectivity and sensitivity during odour perception and processing. This study sets out to determine whether and to which extent the antennal loaded SaveOBP10 in English grain aphid Sitobion avenae, contributes in olfactory processing during host selection. To understand this possible relationship, we purified the SaveOBP10 recombinant protein and performed fluorescence ligand binding tests, molecular docking, RNA interference (RNAi) and behavioural trials. The results showed that SaveOBP10 had strong binding affinities (Ki ≤5 µM) with most of wheat plant volatiles at pH 5.0 as compared to pH 7.4. In Y-tube olfactometer bioassays, the S. avenae was attracted behaviourally towards pentadecane, butylated hydroxytoluene, tetradecane and ß-caryophyllene however repelled by naphthalene. After RNAi of SaveOBP10, the aphid showed nonattraction towards ß-caryophyllene and nonsignificant behavioural response to pentadecane, butylated hydroxytoluene and tetradecane. Furthermore, the three-dimensional structure modelling and molecular docking of SaveOBP10 were performed to the volatiles with high binding abilities. Together these findings indicate that SaveOBP10 can bind more strongly to the volatiles that involved in S. avenae behaviour regulation and possibly will contribute effectively in S. avenae integrated pest management.

The Toxicity of Eichhornia crassipes Fractionated Extracts against Aphis craccivora and Its Safety in Albino Rats.

Eichhornia crassipes were evaluated in order to investigate the insecticidal activity towards Aphis craccivora adults. The LC50 values were promising and reflected the bio-efficacy of the tested extracts (39 and 42 mg/L), respectively, and reduced the fecundity markedly. Using GC/MS analysis, the major components were n-hexadecanoic, linolenic, hexadecenoic, myristic, stearic acids, linolelaidic acid, methyl ester and some terpenoids, alkaloids, and hydrocarbons. A safety assessment of non-target organisms is essential for the development of new pesticides. In order to guide the rational use of the most potential insecticidal extracts AcF and EtF, the effect of these extracts on body weight, hematological indices, biochemical indicators, and histopathology of some relevant organs of albino rats (as a model for mammals) was investigated. The research outcomes revealed that the LC50 of AcF and EtF extracts had gradually raised body weight for 14 days (p > 0.05). Similarly, there were no remarkable alternations in the complete blood count (CBC); only a slight decrease in the monocytes count (612 ± 159.80 × 103 µL) in the EtF-treated group. There was a notable increase in alanine transferase (ALT) activity (36.73 ± 1.44 IU/L) in the AcF-treated group. No destructive changes were noted with the remaining biochemical parameters. Cholesterol and triglycerides non-significantly increased in the EtF group, whereas, cholesterol levels decreased significantly in the AcF group. In addition, histopathological examination reflected minor changes in AcF and EtF groups in the form of mild inflammation in the lungs and mild vacuolar degeneration in the kidneys, while no lesions were detected in the heart and liver in the same groups. Thus, the present research suggested that AcF and EtF extracts of E. crassipes are safe green insecticides for insect control strategies.

Volatiles and hormones mediated root-knot nematode induced wheat defense response to foliar herbivore aphid.

Plant root-leaf communication signals are critical for plant defense. Numerous studies show that belowground organisms can alter systemically resistance traits in aboveground parts against herbivores. However, there are limited studies on root-knot nematode-aphid interaction. Moreover, the impact of nematode's initial density and infection time on plant defense is poorly understood. Here we aim to examine the induced defense responses by root-knot nematode Meloidogyne incognita against aboveground feeding aphid Sitobion avenae in wheat. Further, we investigated the influence of the nematode infection density as well as the length of infection in these interactions. We tested the direct and indirect defense responses triggered by M. incognita against S. avenae as well as how the responses affect the preference of Harmonia axyridis. Plant volatiles and hormones were determined to explore plant defense mechanisms that mediate aboveground-belowground defense. The photosynthetic rate was tested to examine plant tolerance strategy. We found that, both low and high densities M. incognita root infection at 7 days post inoculation (dpi) reduced the feeding of the aphid S. avenae. Behavioral assay showed that H. axyridis preferred plants co-damaged by both M. incognita and S. avenae at 7 dpi. M. incognita infection induced the changes of jasmonic acid, salicylic acid and volatile content, which mediated plant response to S. avenae. Furthermore, photosynthetic rate in wheat increased at 5 dpi under 300 M. incognita or 1000 M. incognita infection. These results suggest that plant roots induced multiple defense strategies against foliar herbivores as damages increased. Our study provides evidence of a complex dynamic response of wheat aboveground defense against aphids in response to belowground nematode damage on a temporal scale.

Molecular Characterization and Expression Patterns of Two Pheromone-Binding Proteins from the Diurnal Moth Phauda flammans (Walker) (Lepidoptera: Zygaenoidea: Phaudidae).

Sex pheromone-binding proteins (PBPs) play an important role in sex pheromone recognition in Lepidoptera. However, the mechanisms of chemical communication mediating the response to sex pheromones remain unclear in the diurnal moths of the superfamily Zygaenoidea. In this study, Phauda flammans (Walker) (Lepidoptera: Zygaenoidea: Phaudidae) was used as a model insect to explore the molecular mechanism of sex pheromone perception in the superfamily Zygaenoidea. Two novel pheromone-binding proteins (PflaPBP1 and PflaPBP2) from P. flammans were identified. The two pheromone-binding proteins were predominantly expressed in the antennae of P. flammans male and female moths, in which PflaPBP1 had stronger binding affinity to the female sex pheromones Z-9-hexadecenal and (Z, Z, Z)-9, 12, 15-octadecatrienal, PflaPBP2 had stronger binding affinity only for (Z, Z, Z)-9, 12, 15-octadecatrienal, and no apparent binding affinity to Z-9-hexadecenal. The molecular docking results indicated that Ile 170 and Leu 169 are predicted to be important in the binding of the sex pheromone to PflaPBP1 and PflaPBP2. We concluded that PflaPBP1 and PflaPBP2 may be responsible for the recognition of two sex pheromone components and may function differently in female and male P. flammans. These results provide a foundation for the development of pest control by exploring sex pheromone blocking agents and the application of sex pheromones and their analogs for insect pests in the superfamily Zygaenoidea.

Appraisal of MsepCSP14 for chemosensory functions in Mythimna separata.

Chemosensory proteins (CSPs) have great contributions in performing diverse functions in insects. However, physiological appraisal of chemosensory protein genes still remains elusive in insects. We studied expression patterns and binding affinities of MsepCSP14, a chemosensory protein, in Mythimna separata. The distinct functions of MsepCSP14 were validated by employing different molecular techniques. The MsepCSP14 had high resemblance of sequence with chemosensory proteins of other insect family members. The MsepCSP14 expression was higher in antennal tissues of females than other tissues. Fluorescence binding assay validated that binding of nine out of 21 ligands to MsepCSP14 was higher at pH 7.4 than at pH 5.0. Three dimensional modeling (3D) and docking analysis predicted that amino acid residues of MsepCSP14 were involved in binding of compounds, and behavior assay displayed that adults of M. separata considerably responded to four volatiles from compounds demonstrating strong binding ability to MsepCSP14. Results of the present study suggest that MsepCSP14 is likely to mediate chemosensory functions in M. separata.

BarH1 regulates odorant-binding proteins expression and olfactory perception of Monochamus alternatus Hope.

Insect odorant-binding proteins (OBPs) are a class of small soluble proteins that can be found in various tissues wherein binding and transport of small molecules are required. Thus, OBPs are not only involved in typical olfactory function by specific activities with odorants but also participate in other physiological processes in non-chemosensory tissues. To better understand the complex biological functions of OBPs, it is necessary to study the transcriptional regulation of their expression patterns. In this paper, an apparent gradient expression pattern of Obp19, that was highly and specifically expressed in antennae and played an essential role in the detection of camphene, was defined in the antennae of the Japanese pine sawyer. Further, the transcription factor BarH1, that also presented gradient expression pattern in antennae, was found to regulate expression of Obp19 directly through binding to its upstream DNA sequence. The condition of BarH1 gene silence, the gene expression levels of Obp19 significantly decreased. At the same time, additional olfactory genes also were regulated and thus influence camphene reception. These findings provide us an opportunity to incorporate Obps in the gene regulatory networks of insects, which contribute to a better understanding of the multiplicity and diversity of OBPs and the olfactory mediated behaviors.

Design, Synthesis, Biological Evaluation, and Computational Studies of Novel Fluorinated Candidates as PI3K Inhibitors: Targeting Fluorophilic Binding Sites.

Highly fluorinated candidates containing anticancer pharmacophores like thiosemicarbazone (5a-e) and its cyclic analogues hydrazineylidenethiazolidine (6a-e), 2-aminothiadiazole (7a-e), and 2-hydrazineylidenethiazolidin-4-one (8a-e) were synthesized, and their cytotoxic activity was assayed against 60 tumor cell lines. Compounds 6c, 7b, and 8b displayed the most potent activity with lower toxic effects on MCF-10a. In vitro phosphatidylinositol 3-kinase (PI3K) enzyme inhibition was performed. Compound 6c displayed half-maximal inhibitory concentration (IC50, µM) values of 5.8, 2.3, and 7.9; compound 7b displayed IC50 values of 19.4, 30.7, and 73.7; and compound 8b displayed IC50 values of 77.5, 53.5, and 121.3 for PI3Kα, ß, and δ, respectively. Moreover, cell cycle progression caused cell cycle arrest at the S phase for compounds 6c and 8b and at G1/S for compound 7b, while apoptosis was induced. In silico studies; molecular docking; physicochemical parameters; and absorption, distribution, metabolism, excretion, and toxicity (ADMET) analysis were performed. The results showed that compound 6c is the most potent one with a selectivity index (SI) of 39 and is considered as a latent lead for further optimization of anticancer agents.

A Salivary Odorant-Binding Protein Mediates Nilaparvata lugens Feeding and Host Plant Phytohormone Suppression.

Odorant-binding proteins (OBPs) typically act as transporters of odor molecules and play an important role in insect host location. Here, we identified an OBP in brown planthopper (BPH) Nilaparvata lugens salivary glands via transcriptome sequencing. Real-time quantitative PCR and Western blotting analysis results showed that NlugOBP11 was highly expressed in salivary glands and secreted into rice plant during feeding, suggesting that it assists in BPH feeding on rice. Functional analysis in N. lugens saliva revealed that silencing this gene by RNA interference decreased the BPH stylet performance in the phloem of rice plants, reduced sap sucking, and ultimately led to insect death. Moreover, overexpression of NlugOBP11 in rice protoplasts or Nicotiana benthamiana leaves inhibited the production of defense-related signaling molecule salicylic acid in rice plant. The results demonstrate that NlugOBP11 is not only essential for BPH feeding, but also acts as an effector that inhibits plant defense.

Phytopathogenic infection alters rice-pest-parasitoid tri-trophic interactions.

BACKGROUND: Plant pathogens and pests often occur together, causing damage while interfering with plant growth. The effects of phytopathogenic infections on plant-herbivore-natural enemy tri-trophic interactions (TTIs) have been extensively investigated, but little is known about how the interval of infection influences such relationships. Here, the effect of rice plants infected by the phytopathogen Rhizoctonia solani on the herbivorous rice brown planthopper (BPH) and associated egg parasitoid Anagrus nilaparvatae over a temporal scale was examined. RESULTS: Our results showed that rice plants infected by R. solani showed increased volatile profiles and significantly attracted BPH and A. nilaparvatae at 5-15 days post infection (DPI) and 5-10 DPI, respectively, when compared with healthy plants. Jasmonic acid and salicylic acid content decreased significantly in BPH-damaged plants after 15 DPI, whereas oxalic acid accumulated soon after 5 DPI when compared with healthy plants. To adapt to adverse environment, BPH laid more eggs and developed into macropterous adults. Under field conditions, R. solani infection had no substantial effect on the arthropod community when compared with healthy plants. CONCLUSION: Taken together, R. solani infection altered rice-pest-parasitoid TTIs over a temporal scale. This result will shed more light on our understanding of plant pathogen-insect cross-talk essential for developing novel pest management strategies. © 2021 Society of Chemical Industry.

Construction, petro-collecting/dispersing capacities, antimicrobial activity, and molecular docking study of new cationic surfactant-sulfonamide conjugates.

Surfactants with their diverse activities have been recently involved in controlling the spread of new coronavirus (COVID-19) pandemic as they are capable of disrupting the membrane surrounding the virus. Using hybrids approach, we constructed a novel series of cationic surfactant-sulfonamide conjugates (3a-g) through quaternization of the as-prepared sulfonamide derivatives (2a-g) with n-hexadecyl iodide followed by structural characterization by spectroscopy (IR and NMR). Being collective properties required in petroleum-processing environment, the petro-collecting/dispersing capacities on the surface of waters with different degrees of mineralization, and the antimicrobial performance against microbes and sulfate-reducing bacteria (SRB) that mitigate microbiological corrosion were investigated for the synthesized conjugates. Among these conjugates, 3g (2.5% aq. solution) exhibited the strongest ability to disperse the thin petroleum film on the seawater surface, whereas KD is 95.33% after 96 h. In diluted form, 3f collected the petroleum layer on distilled water surface (Kmax = 32.01) for duration exceeds 4 days. Additionally, almost all compounds revealed high potency and comparable action with standard antimicrobials, especially 3b and 3f, which emphasize their role as potential biocides. Regarding biocidal activity against SRB, 3g causes a significant reduction in the bacterial count from 2.8 × 106 cells/mL to Nil. Moreover, the conducted molecular docking study confirms the strong correlation between RNA polymerase binding with bioactivity against microbes over other studied proteins (threonine synthase and cyclooxygenase-2).

Heavy Metals and Pesticides Toxicity in Agricultural Soil and Plants: Ecological Risks and Human Health Implications.

Environmental problems have always received immense attention from scientists. Toxicants pollution is a critical environmental concern that has posed serious threats to human health and agricultural production. Heavy metals and pesticides are top of the list of environmental toxicants endangering nature. This review focuses on the toxic effect of heavy metals (cadmium (Cd), lead (Pb), copper (Cu), and zinc (Zn)) and pesticides (insecticides, herbicides, and fungicides) adversely influencing the agricultural ecosystem (plant and soil) and human health. Furthermore, heavy metals accumulation and pesticide residues in soils and plants have been discussed in detail. In addition, the characteristics of contaminated soil and plant physiological parameters have been reviewed. Moreover, human diseases caused by exposure to heavy metals and pesticides were also reported. The bioaccumulation, mechanism of action, and transmission pathways of both heavy metals and pesticides are emphasized. In addition, the bioavailability in soil and plant uptake of these contaminants has also been considered. Meanwhile, the synergistic and antagonistic interactions between heavy metals and pesticides and their combined toxic effects have been discussed. Previous relevant studies are included to cover all aspects of this review. The information in this review provides deep insights into the understanding of environmental toxicants and their hazardous effects.

Structure-based design, synthesis, and biological evaluation of novel piperine-resveratrol hybrids as antiproliferative agents targeting SIRT-2.

A series of novel piperine-resveratrol hybrids 5a-h was designed, synthesized, and structurally elucidated by IR, and 1H, 13C, and 19F NMR. Antiproliferative activities of 5a-h were evaluated by NCI against sixty cancer cell lines. Compound 5b, possessing resveratrol pharmacophoric phenolic moieties, showed a complete cell death against leukemia HL-60 (TB) and Breast cancer MDA-MB-468 with growth inhibition percentage of -0.49 and -2.83, respectively. In addition, 5b recorded significant activity against the other cancer cell lines with growth inhibition percentage between 80 to 95. New 5a-h hybrids were evaluated for their inhibitory activities against Sirt-1 and Sirt-2 as molecular targets for their antiproliferative action. Results showed that compounds 5a-h were more potent inhibitors of Sirt-2 than Sirt-1 at 5 µm and 50 µm. Compound 5b showed the strongest inhibition of Sirt-2 (78 ± 3% and 26 ± 3% inhibition at 50 µM and 5 µM, respectively). Investigation of intermolecular interaction via Hirschfeld surface analysis indicates that these close contacts are mainly ascribed to the O-H⋯O hydrogen bonding. To get insights into the Sirt-2 inhibitory mechanism, a docking study was performed where 5b was found to fit nicely inside both extended C-pocket and selectivity pocket and could compete with the substrate acyl-Lys. Another possible binding pattern showed that 5b could act by partial occlusion of the NAD+ C-pocket. Collectively, these findings would contribute significantly to better understanding the Sirt-2 inhibitory mechanism in order to develop a new generation of refined and selective Sirt-2 inhibitors.