Characterization of a Chitin Synthase Encoding Gene and Effect of Diflubenzuron in Soybean Aphid, Aphis Glycines

Chitin synthases are critical enzymes for synthesis of chitin and thus for subsequent growth and development in insects. We identified the cDNA of chitin synthase gene (CHS) in Aphis glycines, the soybean aphid, which is a serious pest of soybean. The full-length cDNA of CHS in A. glycines (AyCHS) was 5802 bp long with an open reading frame of 4704 bp that encoded for a 1567 amino acid residues protein. The predicted AyCHS protein had a molecular mass of 180.05 kDa and its amino acid sequence contained all the signature motifs (EDR, QRRRW and TWGTR) of chitin synthases. The quantitative real-time PCR (qPCR) analysis revealed that AyCHS was expressed in all major tissues (gut, fat body and integument); however, it had the highest expression in integument (~3.5 fold compared to gut). Interestingly, the expression of AyCHS in developing embryos was nearly 7 fold higher compared to adult integument, which probably is a reflection of embryonic molts in hemimetabolus insects. Expression analysis in different developmental stages of A. glycines revealed a consistent AyCHS expression in all stages. Further, through leaf dip bioassay, we tested the effect of diflubenzuron (DFB, Dimilin ®), a chitin-synthesis inhibitor, on A. glycines'' survival, fecundity and body weight. When fed with soybean leaves previously dipped in 50 ppm DFB solution, A. glycines nymphs suffered significantly higher mortality compared to control. A. glycines nymphs feeding on diflubenzuron treated leaves showed a slightly enhanced expression (1.67 fold) of AyCHS compared to nymphs on untreated leaves. We discussed the potential applications of the current study to develop novel management strategies using chitin-synthesis inhibitors and using RNAi by knocking down AyCHS expression.     

Economics of fed-batch operation: a computer-aided approach

The widely anticipated economic potential of fed-batch operation was quantified for a therapeutic product by flowsheet simulation. A process for production of t-PA from CHO cells based on fed-batch operation was compared to a base process that operates in batch mode. Two cases of fed-batch operation were considered, case A, where the product concentration was assumed to be four times the concentration obtained with base process and case B, where the concentration was eight times. The simulator, Bioprocess Simulator (BPS) from Aspen Technology, reported the final bioreactor volume and the total amount of the continuous feeds added during the fed-batch operation. BPS was also used to simulate the downstream processes. Comparison of the economic performances of the processes revealed that return on investment (ROI) of the base process would increase by 112% by switching to case A fed-batch operation from batch mode. Case B, on the other hand, would result in an increase of 288%. The importance of downstream processing for recovery of high-value products became apparent from this study. A breakdown of equipment purchase cost showed that the contribution from the product recovery section increased from 62% for base case to 77% for case A as the product concentration increased by fed-batch operation. For a fixed recovery of 40%, contribution from the downstream section was found to decrease to 70% for case B compared to case A. It was concluded from the results that higher product concentration would not result in proportionate increase in ROI because of limitations in the recovery section. A sensitivity analysis was carried out on several uncertainties of the simulated fed-batch process.     

Sorbus aucuparia L. Fruit Is a Source of the Drug for Increasing the Efficiency of Tumor Chemotherapy

Russian Journal of Bioorganic Chemistry - The composition of phenolic compounds of rowanberry (Sorbus aucuparia L.) fruit extracts prepared with 40% ethanol and 95% acidified ethanol was studied....     

Herbivore and phytohormone induced defensive response in kale against cabbage butterfly, Pieris brassicae Linn

The constitutive and induced resistance were studied in two varieties (Khanyari and Kawdari) of kale, Brassica oleracea var. acephala in response to cabbage butterfly, Pieris brassicae infestation and exogenous application of jasmonic acid (JA) and salicylic acid (SA). Phenols, condensed tannins, flavonoids and proteins were measured at six days after JA (1?mM) and SA (1?mM) application and/or insect infestation. Plant damage and larval weights were also recorded. Khanyari variety showed highest amounts of phenols (208.23?μg/g FW), condensed tannin (347.76?μg/g FW), flavonoids (175.61?μg/g FW) and proteins (0.71?mg/g FW) in plants pre-treated with JA and infested with insects. The PAL activity was high in response to JA application followed by insect infestation. Insects reared on Khanyari and Kawdari plants pre-treated with JA prior showed significantly reduced larval weights (97.88 and 102.46?mg, respectively). Damage was low in plants pre-treated with JA in Khanyari at 3, 6 and 9?days after treatment (10.52%, 8.52%, and 5.30%, respectively). Thus, JA can play an important role in plant defense in kale against P. brassicae.     

Parental genome composition and genetic classifications of derivatives from intergeneric crosses of Festuca mairei and Lolium perenne

Intergeneric hybridization between Festuca and Lolium has been a long-term goal of forage and turfgrass breeders to generate improved cultivars by combining stress tolerance of Festuca and rapid establishment of Lolium. However, wide-distance hybridizations usually result in the wild genome being eliminated from the hybrid due to incomplete chromosome pairing and crossovers. In this study, random amplified polymorphic DNA (RAPD) and simple sequence repeat (SSR) markers were used to detect the parental genome composition of F₁ hybrids and backcross, generated from crosses between Festuca mairei St. Yves (Fm) and Lolium perenne L. (Lp). Each of the hybrids exhibited integration of Fm and Lp genomes with varying levels of Fm/Lp genome ratios. However, cluster and principle component analyses of the progeny consistently revealed four groups depending on the amount of genome introgression from both parents. The parental genome composition and classifications of intergeneric progeny would be useful for breeding material selection. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Genetic analysis of the pnp-deaD genetic region reveals membrane lipoprotein NlpI as an independent participant in cold acclimatization of Salmonella enterica serovar Typhimurium

Plasmid pAMI7 of the methylotrophic bacterium Paracoccus aminophilus JCM 7686 (Alphaproteobacteria) encodes a functional type II restriction-modification (R-M) system designated PamI. Homologous systems were identified in the genomes of distinct taxonomic groups of Bacteria and Archaea, which provides evidence that horizontal gene transfer has contributed to the wide dissemination of R-M modules - even between domains. Analysis of the cleavage specificity of the R.PamI endonuclease revealed that this protein is an isoschizomer of restriction enzyme NcoI. Interestingly, bioinformatic analyses suggest that R.PamI and NcoI are accompanied by methyltransferases of different methylation specificities (C5-methylcytosine and N4-methylcytosine methyltransferases, respectively), which possibly exemplifies recombinational shuffling of genes coding for individual components of R-M systems. The PamI system can stabilize plasmid pAMI7 in a bacterial population, most probably at the postsegregational level. Therefore, it functions in an analogous manner to plasmid-encoded toxin-antitoxin (TA) systems. Since the TA system of pAMI7 is nonfunctional, it is highly probable that this lack is compensated by the stabilizing activity of PamI. This indicates the crucial role of the analyzed R-M system in the stable maintenance of pAMI7, which is, to our knowledge, the first report of 'symbiosis' between a R-M system and a plasmid in the Alphaproteobacteria.     

G2/M cell cycle arrest by an N-acetyl-D-glucosamine specific lectin from Psathyrella asperospora

A new N-acetyl-D-glucosamine (GlcNAc) specific lectin was identified and purified from the fruiting body of the Australian indigenous mushroom Psathyrella asperospora. The functional lectin, named PAL, showed hemagglutination activity against neuraminidase treated rabbit and human blood types A, B and O, and exhibited high binding specificity towards GlcNAc, as well as mucin and fetuin, but not against asialofetuin. PAL purified to homogeneity by a combination of ammonium sulfate precipitation, chitin affinity chromatography and size exclusion chromatography, was monomeric with a molecular mass of 41.8 kDa, was stable at temperatures up to 55 °C and between pH 6–10, and did not require divalent cations for optimal activity. De novo sequencing of PAL using LC-MS/MS, identified 10 tryptic peptides that revealed substantial sequence similarity to the GlcNAc recognizing lectins from Psathyrella velutina (PVL) and Agrocybe aegerita (AAL-II) in both the carbohydrate binding and calcium binding sites. Significantly, PAL was also found to exert a potent anti-proliferative effect on HT29 cells (IC₅₀ 0.48 μM) that was approximately 3-fold greater than that observed on VERO cells; a difference found to be due to the differential expression of cell surface GlcNAc on HT29 and VERO cells. Further characterization of this activity using propidium iodine staining revealed that PAL induced cell cycle arrest at G₂/M phase in a manner dependent on its ability to bind GlcNAc.     

Modulation of Biofilm-Formation in Salmonella enterica Serovar Typhimurium by the Periplasmic DsbA/DsbB Oxidoreductase System Requires the GGDEF-EAL Domain Protein STM3615

In Salmonella enterica serovar Typhimurium (S. Typhimurium), biofilm-formation is controlled by the cytoplasmic intracellular small-molecular second messenger cyclic 3′, 5′-di- guanosine monophosphate (c-di-GMP) through the activities of GGDEF and EAL domain proteins. Here we describe that deleting either dsbA or dsbB, respectively encoding a periplasmic protein disulfide oxidase and a cytoplasmic membrane disulfide oxidoreductase, resulted in increased biofilm-formation on solid medium. This increased biofilm-formation, defined as a red, dry and rough (rdar) colony morphotype, paralleled with enhanced expression of the biofilm master regulator CsgD and the biofilm-associated fimbrial subunit CsgA. Deleting csgD in either dsb mutant abrogated the enhanced biofilm-formation. Likewise, overexpression of the c-di-GMP phosphodiesterase YhjH, or mutationally inactivating the CsgD activator EAL-domain protein YdiV, reduced biofilm-formation in either of the dsb mutants. Intriguingly, deleting the GGDEF-EAL domain protein gene STM3615 (yhjK), previously not connected to rdar morphotype development, also abrogated the escalated rdar morphotype formation in dsb mutant backgrounds. Enhanced biofilm-formation in dsb mutants was furthermore annulled by exposure to the protein disulfide catalyst copper chloride. When analyzed for the effect of exogenous reducing stress on biofilm-formation, both dsb mutants initially showed an escalated rdar morphotype development that later dissolved to reveal a smooth mucoid colony morphotype. From these results we conclude that biofilm-development in S. Typhimurium is affected by periplasmic protein disulphide bond status through CsgD, and discuss the involvement of selected GGDEF/EAL domain protein(s) as signaling mediators.     

Evaluation of anti-nociceptive,anti-inflammatory and antipyretic potential of Mikania cordata (Burm. f.) Robinson in experimental animal model

Mikania cordata is widely used for the treatment of cuts, wounds, and dengue fever in Bangladesh. In the present study, essential oil (12.5, 25 and 50?mg/kg) and two extracts, viz., chloroform and ethyl acetate extracts (200, 400, 800?mg/kg b.w.) were tested for peripheral and central anti-nociceptive activity by acetic acid-induced writhing and hot plate method, respectively. Carrageenan-induced rat paw edema assay and yeast-induced hyperthermia assay were also carried out to evaluate anti-inflammatory and antipyretic properties of oil and extracts, respectively at aforesaid doses. The essential oil (50?mg/kg), chloroform extract (800?mg/kg) and ethyl acetate extract (800?mg/kg) showed potent peripheral anti-nociceptive activity having 47.33%, 29.33% and 16.65% of writhing inhibition, respectively, comparable with standard diclofenac (52.0%). Essential oil (50?mg/kg), chloroform extract (800?mg/kg) and ethyl acetate extract (800?mg/kg) presented promising central anti-nociceptive activity as well having 95.86%, 79.18% and 42.37% elongation of reaction time, respectively, at 90?min after administration of essential oil, ethyl acetate extract and 60?min after administration of chloroform extract. In anti-inflammatory activity screening, the essential oil (50?mg/kg) produced the highest 72.80% edema inhibition at 4?h after administration of carrageenan which was comparable with that of standard phenylbutazoe (87.87%). On the other hand, chloroform extract (800?mg/kg) and ethyl acetate extract (800?mg/kg) showed up to 34.31% and 15.27% of edema inhibition, respectively, at 4?h after administration of carrageenan. In antipyretic assay, the essential oil and chloroform extract displayed a strong antipyretic effect in yeast-induced rats, whereas the ethyl acetate extract had no antipyretic activity. The present study revealed anti-nociceptive, anti-inflammatory and antipyretic potential of M. cordata which could be the therapeutic option against fever, inflammations as well as painful conditions and confirmed the traditional use of M. cordata.