不同气候适应类型果蝇体色黑化可塑性的适应性变化(英文)

变温昆虫果蝇Drosophila深受热选择（即遗传效应）或表型诱导效应（即可塑性）的影响。表型可塑性是不同生物进行适应的有效方法, 但是它在不同的果蝇种中较少受到关注。 我们分析了不同发育温度范围和地理分布的果蝇的黑化反应模式。嗜凤梨果蝇D. ananassae 和蒲桃果蝇D. jambulina 对低温敏感, 这些物种可在18~32℃下饲育。相反, D. nepalensis 为耐冷且对热敏感的物种, 可在12~25℃下饲育。世界广为分布的黑腹果蝇D. melanogaster的温度范围宽（13~31℃）, 该物种前3个腹节和后3个腹节的黑化反应模式未见明显差异。D. nepalensis的全部6个腹节（第2~7节）均具有高度的可塑性。不过, 黑腹果蝇D. melanogaster只有后3个腹节具有可塑性。相反, 热带物种嗜凤梨果蝇D. ananassae 的所有腹节均不具有可塑性。世界广为分布的黑腹果蝇, 即使来自冷得多的气候环境, 其体色也不加深, 与D. nepalensis中观察到的体色接近。本研究的目的旨在认识引起体色的形态多样性的过程以及果蝇对不同地理区域的适应性。最后, 将体色黑化与物种系统发育谱系的比较表明, 在不同的演化谱系中不断发生遗传多态性或表型可塑性两种不同模式的适应。     

Evaluation of metal mobility/immobility in fly ash induced by bacterial strains isolated from the rhizospheric zone of Typha latifolia growing on fly ash dumps

In this investigation, 11 bacterial strains were isolated from the rhizospheric zone of Typha latifolia. All the strains were aerobic, showed positive result with indole production and were able to grow in MacConkey agar. However, four strains were gram positive and others gram negative. These strains were inoculated separately in the fly ash with additional source of carbon to test their ability to increase the bioavailability or immobilization of toxic metals like Cu, Zn, Pb, Cd and Mn. It was observed that most of the bacterial strains either enhanced the mobility of Zn, Fe and Mn or immobilized Cu and Cd. However, there were a few exceptions. For example, in contrast to other bacterial strains, NBRFT6 enhanced immobility of Zn and Fe and NBRFT2 of Mn. On the other hand, in place of immobility induced by most of the bacterial strains, NBRFT8 and NBRFT9 enhanced bioavailability of Cu. However, in case of Cd, all the strains without any exception immobilized this metal. The results also indicated that the mobility/immobility of trace metals from the exchangeable fractions was the specific function of bacterial strains depending upon the several edaphic and environmental factors. Based on the extractability of metals from fly ash, a consortium of high performer bacterial strains will be further used to enhance the phytoextraction of metals from fly ash by metal accumulating plants. On the other hand, bacterial strains responsible for immobilization of metals may be used for arresting their leaching to water bodies.     

Synthesis and in vitro evaluation of the antifungal activities of dihydropyrimidinones

Copper (II) chloride in the absence of any solvent, efficiently catalyses the synthesis of dihydropyrimidinones (80-96% yields) by the Biginelli reaction. Six compounds were selected and examined their antifungal activities against the radial growth of three fungal species viz., Trichoderma hammatum, Trichoderma koningii and Aspergillus niger.     

GBS-SNP and SSR based genetic mapping and QTL analysis for drought tolerance in upland cotton

A recombinant inbred line mapping population of intra-species upland cotton was generated from a cross between the drought-tolerant female parent (AS2) and the susceptible male parent (MCU13). A linkage map was constructed deploying 1,116 GBS-based SNPs and public domain-based 782 SSRs spanning a total genetic distance of 28,083.03 cM with an average chromosomal span length of 1,080.12 cM with inter-marker distance of 10.19 cM.A total of 19 quantitative trait loci (QTLs) were identified in nine chromosomes for field drought tolerance traits. Chromosomes 3 and 8 harbored important drought tolerant QTLs for chlorophyll stability index trait while for relative water content trait, three QTLs on chromosome 8 and one QTL each on chromosome 4, 12 were identified. One QTL on each chromosome 8, 5, and 7, and two QTLs on chromosome 15 linking to proline content were identified. For the nitrate reductase activity trait, two QTLs were identified on chromosome 3 and one on each chromosome 8, 13, and 26. To complement our QTL study, a meta-analysis was conducted along with the public domain database and resulted in a consensus map for chromosome 8. Under field drought stress, chromosome 8 harbored a drought tolerance QTL hotspot with two in-house QTLs for chlorophyll stability index (qCSI01, qCSI02) and three public domain QTLs (qLP.FDT_1, qLP.FDT_2, qCC.ST_3). Identified QTL hotspot on chromosome 8 could play a crucial role in exploring abiotic stress-associated genes/alleles for drought trait improvement.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12298-021-01041-y.     

Lipid synthesis inhibitors: Effect on epidermal lipid conformational changes and percutaneous permeation of levodopa

A combination of lipid synthesis inhibitors was used to enhance the in vitro and in vivo permeation of levodopa (LD) across rat epidermis, and their influence on epidermal lipids was investigated using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. Rat epidermis was treated with ethanol and a combination of atorvastatin (750 μg/7 cm²), cerulenin (20 μg/7 cm²), and β-chloroalanine (600 μg/7 cm²) for sustaining the reduced content of epidermal cholesterol, fatty acids (as triglycerides), and ceramide (as sphingosine), respectively, in viable rat skin. This treatment resulted in significant (P<.05) synthesis inhibition of skin lipids up to 48 hours and 6-fold enhancement in the in vitro permeation of LD. The effective plasma concentration of LD was achieved within 1 hour and maintained over 48 hours after topical application to rat epidermis treated with a combination of these lipid synthesis inhibitors. ATR-FTIR studies of inhibitor(s)-treated rat epidermis revealed a significant decrease (P<.05) in peak height and area for both asymmetric and symmetric C−H stretching absorbances, suggesting extraction of lipids. However, an insignificant (P<.05) shift in the frequency of these peaks suggested no fluidization of epidermal lipids by lipid synthesis inhibitors. A direct correlation was observed between epidermal lipid synthesis inhibition, decrease in peak height or area, and percutaneous permeation of LD. Skin lipid synthesis inhibition by a combination of lipid synthesis inhibitors seems to offer a feasible approach for enhancing the transcutaneous delivery of LD. Published: October 24, 2005     

Computational and Biochemical Docking of the Irreversible Cocaine Analog RTI 82 Directly Demonstrates Ligand Positioning in the Dopamine Transporter Central Substrate-binding Site

The dopamine transporter (DAT) functions as a key regulator of dopaminergic neurotransmission via re-uptake of synaptic dopamine (DA). Cocaine binding to DAT blocks this activity and elevates extracellular DA, leading to psychomotor stimulation and addiction, but the mechanisms by which cocaine interacts with DAT and inhibits transport remain incompletely understood. Here, we addressed these questions using computational and biochemical methodologies to localize the binding and adduction sites of the photoactivatable irreversible cocaine analog 3β-(p-chlorophenyl)tropane-2β-carboxylic acid, 4′-azido-3′-iodophenylethyl ester ([¹²⁵I]RTI 82). Comparative modeling and small molecule docking indicated that the tropane pharmacophore of RTI 82 was positioned in the central DA active site with an orientation that juxtaposed the aryliodoazide group for cross-linking to rat DAT Phe-319. This prediction was verified by focused methionine substitution of residues flanking this site followed by cyanogen bromide mapping of the [¹²⁵I]RTI 82-labeled mutants and by the substituted cysteine accessibility method protection analyses. These findings provide positive functional evidence linking tropane pharmacophore interaction with the core substrate-binding site and support a competitive mechanism for transport inhibition. This synergistic application of computational and biochemical methodologies overcomes many uncertainties inherent in other approaches and furnishes a schematic framework for elucidating the ligand-protein interactions of other classes of DA transport inhibitors.     

Synthesis and in vitro antiviral activities of 3′-fluoro (or chloro) and 2′,3′-difluoro 2′,3′-dideoxynucleoside analogs against hepatitis B and C viruses

Chronic infections with hepatitis B virus (HBV) and hepatitis C virus (HCV) lead to serious liver diseases worldwide. Co-infection with HBV and HCV is very common and is associated with increased risk of liver pathogenesis, liver cancer, and liver failure. Several 5-substituted 3′-fluoro (or chloro) (1–4, 6, 7, 17–19) and 2′,3′-difluoro 2′,3′-dideoxynucleosides (15 and 16) were synthesized and evaluated for in vitro antiviral activities against duck hepatitis B virus (DHBV), human hepatitis B virus, and hepatitis C virus. Of these compounds 4, 7, 17, and 19 demonstrated moderate anti-HBV activity, and 2, 4, 7, 8, and 19 were weak inhibitors of HCV. Although 5-iodo derivative (7) was most inhibitory against HCV, it exhibited a reduction in cellular RNA levels in Huh-7 cells. The 5-hydroxymethyl-3′-fluoro-2′,3′-dideoxyuridine (4) and 1-(3-chloro-2,3-dideoxy-β-d-erythro-pentofuranosyl)-5-fluorouracil (19) provided the most inhibition of both viruses without cytotoxicity.     

Chlorolepiota indica sp. nov.—A new species from India

A new species Chlorolepiota indica is reported from Patiala in Punjab, India. The fungus is characterized by convex brown pileus covered by concentrically arranged brown scales with yellow tinge around the umbo. The stipe of the fruiting body is cream to pale yellow, pinkish to reddish brown near the pileus, and yellowish to dark grey brown towards the base.     

Enzymes of ammonia assimilation and their regulation inAzospirillum lipoferum strain D-2

Azospirillum lipoferum strain D-2 possesses the following enzymes for the assimilation of N₂ and NH ₄ ⁺ : nitrogenase, glutamine synthetase, NADPH-dependent glutamate synthase, NADH-/NADPH-dependent glutamate dehydrogenase, and NADH-dependent alanine dehydrogenase. Nitrogenase and glutamine synthetase are repressed, whereas glutamate dehydrogenase and alanine dehydrogenase are induced by NH ₄ ⁺ . Glutamine synthetase activity is modulated by both repression and depression and also by adenylylation.