Insecticidal Potential of α-Pinene and β-Caryophyllene against <i>Myzus persicae</i> and Their Impacts on Gene Expression

Myzus persicae (M. persicae) is now considered a threat to agricultural crops due to economic losses. Numerous synthetic insecticides applied every year against M. persicae, are reported to be unsafe for environment, humans, and beneficial insects. Furthermore, several species of Myzus have been found to develop resistance due to over application of these insecticides. Therefore, it is required to find some novel insecticide that would be safe for the environment as well as for humans. In the current study, two major pure constituents α-pinene and β-caryophyllene were evaluated for their insecticidal potential against M. persicae using a fumigant toxicity assay. Furthermore, impact of α-pinene and β-caryophyllene on expression of five different genes, e.g., HSP 60, FPPS I, OSD, TOL and ANT responsible for reproduction, dispersion, and growth of M. persicae has also been investigated. To perform fumigant toxicity assay, five different concentrations (3.5, 4, 4.5, 5 and 6 μL L⁻¹) of α-pinene and β-caryophyllene were prepared. Lethal concentration (LC) was calculated, and gene expression studies were executed through qRT PCR at LC₃₀ of α-pinene and β-caryophyllene. Both constituents demonstrated excellent fumigant toxicity effects against M. persicae at all five concentrations. However, α-pinene shows significantly better results (98%) as compared to β-caryophyllene (80%) after 72 h at 6 μL L⁻¹ of dose. The highest upregulation in expression was demonstrated at LC₃₀ dose of α-pinene in five in three out of five genes understudy (TOL, ANT, and FPPS I). Conversely, two genes HSP 60 and OSD demonstrated downregulation at LC₃₀ dose of β-caryophyllene. Conclusively, our results highlighted the promising insecticidal potential of both compounds α-pinene and β-caryophylleneby interfering with the reproduction and development related processes in M. persicae, allowing us to recommend the phytoconstituents under investigation as an ecofriendly alternative to synthetic insecticides.     

Chemical Characterization,Antioxidant, Antimicrobial,Cytotoxicity and in Silico Studies of Hexane Extract and Essential Oils from Citrus limon Leaves

The present study investigates the chemical composition, antioxidant and antimicrobial bioactivities of essential oil and hexane extract from Citrus limon leaves. The isolation of essential oil was carried out using the Clevenger apparatus. The percentage yield of essential oil and hexane extract from Citrus limon leaves was 0.59 and 0.50 %, respectively. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) scavenging assay highlighted that Citrus limon leaves essential oil (CLEO) and hexane extract exhibited the significant antioxidant potential of 69.64 and 67.55 %, respectively, compared to the BHT standard. Similarly, a significant inhibition in linoleic acid peroxidation was recorded in both CLEO (81.93 %) and hexane extract (50.34 %). Characterization of chemical constituents in CLEO and extract was executed using GC/MS, where Limonene was detected as a major compound in CLEO (60.52 %) and hexane extract (73.62 %). The haemolytic activity ranged from 2.46 to 5.75 % revealing negligible cytotoxicity of CLEO and hexane extract. In silico studies agree with the in vitro antimicrobial studies, where vinimalol, taraxasterol, and moretenol present in CLEO showed strong interactions/inhibition against dihydroorotase and DNA gyrase from E. coli, and the tyrosyl-tRNA synthetase and DNA gyrase from S. aureus. Based on the current data, it may be concluded that both CLEO and hexane extract possessed significant bioactivities, such as antimicrobial and antioxidant activity, with minimal cytotoxicity.     

Synthesis of sucrose epoxides,partial de-esterification of 1′,2:4,6-di-O-isopropylidenesucrose tetra-acetate,and selective tosylation of 3,6′-di-O-acetyl-1′,2:4,6-di-O-isopropylidenesucrose

Selective de-esterification of 1′,2:4,6-di-O-isopropylidenesucrose tetra-acetate² (1) with methanolic ammonia at ?10° gave an inseparable mixture (2+3) of the 3,4′,6′- and 3,3′,6′-triacetates and also the 4,6′-diacetate 4. When the reaction was performed at 5°, it gave 4, the 4-acetate 8, and the parent diacetal 9. These derivatives allow selective reaction at hydroxyl groups in sucrose, in particular at HO-3′ and, HO-4′, not hitherto possible. Mesylation of 4 gave the 3′,4′-dimesylate 7, which, on treatment with aqueous acetic acid followed by acetylation, afforded 3′,4′-di-O-mesylsucrose hexa-acetate (11). Treatment of 11 with sodium methoxide in methanol at 70° for 1 min gave the ribo-3′,4′-epoxide 12 as the minor, and the lyxo-3′,4′-epoxide 13 as the major, product. Selective tosylation of 4 gave the 3',4'-ditosylate 14 (3.7%), 4′-tosylate 15 (3.1%), and 3'-tosylate 16 (31%), indicating the order of reactivity HO-3′>HO-4′ in 4. De acetalation of 15 and 16 followed by acetylation gave the hepta-acetates of 4′- and 3′-O-tosylsucrose, respectively, which were converted into the respective epoxides, 13 and 12, by methanolic sodium methoxide.     

Synthesis and reactions of cyclic acetal derivatives of 6,6′-dichloro-6,6′-dideoxysucrose

Treatment of 6,6′-dichloro-6,6′-dideoxysucrose with a combination of 2,2-dimethoxypropane, N,N-dimethylformamide, and toluene-p-sulphonic acid (reagent A), followed by acetylation, gave the 1′,2:3,4-diacetal 1 (39%) and the 1′,2-acetal 2 (37%). A similar reaction of methyl 6-chloro-6-deoxy-α-D-glucopyranoside with reagent A yielded the corresponding 2,3- and 3,4-acetal derivatives in yields of 29% and 9%, respectively. The structures of 1 and 2 have been confirmed by ¹H-n.m.r. spectroscopy and by chemical transformations.     

Reproductive tissues-specific meta-QTLs and candidate genes for development of heat-tolerant rice cultivars

Plant Molecular Biology - By integrating genetics and genomics data, reproductive tissues-specific and heat stress responsive 35 meta-QTLs and 45 candidate genes were identified, which could be...     

Kinetics and structure-activity relationship studies on pregnane-type steroidal alkaloids that inhibit cholinesterases

The mechanism of inhibition of acetylcholinesterase (AChE, EC 3.1.1.7) and butyrylcholinesterase (BChE, EC 3.1.1.8) enzymes by 23 pregnane-type alkaloids isolated from the Sarcococca saligna was investigated. Lineweaver-Burk and Dixon plots and their secondary replots showed that the majority of these compounds, that is 1, 4, 5, 6, 9, 10, 12, 13, 15-19, and 21 were found to be noncompetitive inhibitors of both enzymes. Compounds 8, 20, 22, and 23 were determined to be uncompetitive inhibitors of BChE, while compounds 11 and 14 were found to be uncompetitive and linear mixed inhibitors of AChE, respectively. Ki values were found to be in the range of 2.65-250.0 microM against AChE and 1.63-30.0 microM against BChE. The structure-activity relationship (SAR) studies suggested that the major interaction of the enzyme-inhibitor complexes are due to hydrophobic and cation-pi interactions inside the aromatic gorge of these cholinesterases. The effects of various substituents on the activity of these compounds are also discussed in details.     

New pregnane-type steroidal alkaloids from Sarcocca saligna and their cholinesterase inhibitory activity

Five new steroidal alkaloids, 5,14-dehydro-N(a)-demethylsaracodine [3beta-N(a)-methyl-20S-N(b)-acetyl-N(b)-methylamino-pregn-5,14-diene] (1), 14-dehydro-N(a)-demethylsaracodine [3beta-N(a)-methyl-20S-N(b)-acetyl-N(b)-methylamino-5alpha-pregn-14-ene] (2), 16-dehydrosarcorine [(20S)-20-(N,N-dimethylamino)-3beta-(N(a)-acetylamido)-5alpha-pregn-16-ene] (3), 2,3-dehydrosarsalignone [(20S)-20-(N,N-dimethylamino)-3beta-(tigloylamino)-pregn-2,5-diene-4-one] (4), and 14,15-dehydrosarcovagine-D [(20S)-20-(N,N-dimethylamino)-3beta-(tigloylamino)-5alpha-pregn-2,14-diene-4-one] (5), were isolated from the ethanolic extract of Sarcococca saligna, along with two known bases, sarcovagenine-C (6) and salignarine-C (7). Their structures were elucidated on the basis of spectroscopic methods. All seven compounds were found to possess cholinesterase inhibitory potential in a concentration-dependent manner with the IC50 values ranging from 12.5 to 200 microM against acetylcholinesterase and from 1.25 to 32.2 microM against butyrylcholinesterase.     

A genetic linkage map of grape,utilizing <Emphasis Type="Italic">Vitis rupestris</Emphasis> and <Emphasis Type="Italic">Vitis arizonica</Emphasis>

A genetic linkage map of grape was constructed, utilizing 116 progeny derived from a cross of two Vitis rupestris x V. arizonica interspecific hybrids, using the pseudo-testcross strategy. A total of 475 DNA markers-410 amplified fragment length polymorphism, 24 inter-simple sequence repeat, 32 random amplified polymorphic DNA, and nine simple sequence repeat markers-were used to construct the parental maps. Markers segregating 1:1 were used to construct parental framework maps with confidence levels >90% with the Plant Genome Research Initiative mapping program. In the maternal (D8909-15) map, 105 framework markers and 55 accessory markers were ordered in 17 linkage groups (756 cM). The paternal (F8909-17) map had 111 framework markers and 33 accessory markers ordered in 19 linkage groups (1,082 cM). One hundred eighty-one markers segregating 3:1 were used to connect the two parental maps' parents. This moderately dense map will be useful for the initial mapping of genes and/or QTL for resistance to the dagger nematode, Xiphinema index, and Xylella fastidiosa, the bacterial causal agent of Pierce's disease.     

Skeletal muscle myosin heavy chain isoforms and energy metabolism after clenbuterol treatment in the rat

Prolonged treatment with the beta(2)-adrenoceptor agonist clenbuterol (1-2 mg. kg body mass(-1). day (-1)) is known to induce the hypertrophy of fast-contracting fibers and the conversion of slow- to fast-contracting fibers. We investigated the effects of administering a lower dose of clenbuterol (250 microgram. kg body mass(-1). day (-1)) on skeletal muscle myosin heavy chain (MyHC) protein isoform content and adenine nucleotide (ATP, ADP, and AMP) concentrations. Male Wistar rats were administered clenbuterol (n = 8) or saline (n = 6) subcutaneously for 8 wk, after which the extensor digitorum longus (EDL) and soleus muscles were removed. We demonstrated an increase of type IIa MyHC protein content in the soleus from approximately 0.5% in controls to approximately 18% after clenbuterol treatment (P < 0.05), which was accompanied by an increase in the total adenine nucleotide pool (TAN; approximately 19%, P < 0.05) and energy charge [E-C = (ATP + 0.5 ADP)/(ATP + ADP + AMP); approximately 4%; P < 0.05]. In the EDL, a reduction in the content of the less prevalent type I MyHC protein from approximately 3% in controls to 0% after clenbuterol treatment (P < 0.05) occurred without any alterations in TAN and E-C. These findings demonstrate that the phenotypic changes previously observed in slow muscle after clenbuterol administration at 1-2 mg. kg body mass(-1). day(-1) are also observed at a substantially lower dose and are paralleled by concomitant changes in cellular energy metabolism.