Risk assessment of selected insecticides on Tamarixia triozae (Hymenoptera: Eulophidae), a parasitoid of Bactericera cockerelli (Hemiptera: Trizoidae)

Tamarixia triozae (Burks) (Hymenoptera: Eulophidae) is an important parasitoid of the potato or tomato psyllid, Bactericera cockerelli (Sulc) (Hemiptera: Trizoidae), a serious pest of potato (Solanum tuberosum L.), tomato (Solanum lycopersicum L.), and other solanaceous vegetables in many countries. To produce a marketable crop, insecticides are required when B. cockerelli populations reach economically damaging levels. We evaluated 11 commonly used insecticides for their effects on T. triozae. Glass-surface residues of spinetoram, imidacloprid-cyfluthrin, abamectin, and tolfenpyrad caused 100% mortality of T. triozae in 72 h, and the leaf residue of spinetoram was extremely toxic to T. triozae adults; even 15-d-old residues caused 100% mortality. Cyantraniliprole, fenpyroximate, pymetrozine, spirotetramat, spiromesifen, and chenopodium oil did not cause significant mortality in either glass surface or leaf-residue bioassays. Ingestion of spinetoram, abamectin, and imidacloprid+cyfluthrin (Leverage) by the adults resulted in 100% mortality in 12 h, and tolfenpyrad, 75.0% mortality in 12 h; whereas chenopodium oil and pymetrozine showed moderate effects on adult survival. Ingestion of abamectin, imidacloprid-cyfluthrin, and spinetoram killed all adults in the first day of treatment, whereas female adults in the treatment of pymetrozine lived 80.8 d, which was similar to those in the control. Ingestion of abamectin, imidacloprid-cyfluthrin, chenopodium oil, and spinetoram killed all male adults in the first day, whereas ingestion of other insecticides did not cause significant mortality, but reduced percent parasitism. Abamectin, imidacloprid-cyfluthrin, and spinetoram had the most deleterious effects on T. triozae, and have the least potential for use in integrated control programs using this parasitoid.

Removal of phosphorus and nitrogen from domestic wastewater using a mineralized refuse-based bioreactor

Municipal solid waste used for landfill becomes stabilized, or aged, some years after placement, and can be safely excavated; the term 'mineralized refuse' is used in this study. The adsorptions of phosphorus, and the nitrification of the mineralized refuse and clay, were investigated by batch incubation. The variation of phosphorus adsorption in the mineralized refuse was fitted to the Freundlich adsorption isotherm equation, giving a maximum phosphorus adsorption capacity of 2310 mg kg(-1). Based on the Langmuir isotherm equation, maximum phosphorus adsorption capacity was calculated to be 1976 mg kg(-1), almost twice that of the clay. The equations for both the mineralized refuse and clay were fitted to zero-order kinetics (R2 > 0.98, P < 0.01, n = 11), giving concentrations of phosphorus as phosphates less than 250 mg L(-1). The K value for the mineralized refuse was about 3.5 times higher than for the clay. The production of nitrogen as nitrates in both the mineralized refuse and the clay after 120 h incubation yielded a first-order reaction kinetics value of 100 mg kg(-1) NH4(+)-N from the initial concentration. The calculated net nitrification as nitrates for the mineralized refuse was 6.3 times higher than for the clay. Domestic wastewater was then treated in a mineralized refuse-based bioreactor for 30 days. The removal rates of COD(cr), total nitrogen and total phosphorus were 73.77 +/- 8.10%, 61.01 +/- 6.75%, and 69.14 +/- 9.25%, respectively. Large accumulations of nitrates occurred in the mineralized refuse-based bioreactor. For the full-scale design, a high column of mineralized refuse is recommended for the denitrification.

Montelukast, a cysteinyl leukotriene receptor-1 antagonist, attenuates chronic brain injury after focal cerebral ischaemia in mice and rats

OBJECTIVES

Previously we demonstrated the neuroprotective effect of montelukast, a cysteinyl leukotriene receptor-1 (CysLT(1) ) antagonist, on acute brain injury after focal cerebral ischaemia in mice. In this study, we have determined its effect on chronic brain injury after focal cerebral ischaemia in mice and rats.

METHODS

After transient focal cerebral ischaemia was induced by middle cerebral artery occlusion, montelukast was intraperitoneally injected in mice or orally administered to rats for five days. Behavioural dysfunction, brain infarct volume, brain atrophy and neuron loss were determined to evaluate brain lesions.

KEY FINDINGS

Montelukast (0.1 mg/kg) attenuated behavioural dysfunction, brain infarct volume, brain atrophy and neuron loss in mice, which was similar to pranlukast, another CysLT(1) receptor antagonist. Oral montelukast (0.5 mg/kg) was effective in rats and was more effective than edaravone, a free radical scavenger.

CONCLUSION

Montelukast protected mice and rats against chronic brain injury after focal cerebral ischaemia, supporting the therapeutic potential of CysLT(1) receptor antagonists.

Modulation of pantothenate kinase 3 activity by small molecules that interact with the substrate/allosteric regulatory domain

Pantothenate kinase (PanK) catalyzes the rate-controlling step in coenzyme A (CoA) biosynthesis. PanK3 is stringently regulated by acetyl-CoA and uses an ordered kinetic mechanism with ATP as the leading substrate. Biochemical analysis of site-directed mutants indicates that pantothenate binds in a tunnel adjacent to the active site that is occupied by the pantothenate moiety of the acetyl-CoA regulator in the PanK3acetyl-CoA binary complex. A high-throughput screen for PanK3 inhibitors and activators was applied to a bioactive compound library. Thiazolidinediones, sulfonylureas and steroids were inhibitors, and fatty acyl-amides and tamoxifen were activators. The PanK3 activators and inhibitors either stimulated or repressed CoA biosynthesis in HepG2/C3A cells. The flexible allosteric acetyl-CoA regulatory domain of PanK3 also binds the substrates, pantothenate and pantetheine, and small molecule inhibitors and activators to modulate PanK3 activity.

Cloning and expression of three fatty acid desaturase genes from cold-sensitive lima bean (Phaseolus lunatus L.)

The critical chilling temperature of cold-sensitive lima bean (Phaseolus lunatus L.) seedlings was determined to be approx. 8°C. The full-length cDNAs of PlSAD, PlFAD2, and PlFAD3 encoding three fatty acid desaturases were isolated from lima bean leaves. The PlSAD open reading frame (ORF) had 1,317 bp and a single intron of 601 bp, encoding a polypeptide of 438 amino acids that showing 86% homology with the plastidial stearoyl-acyl carrier protein desaturase in soybean. The PlFAD2 ORF contained 1,059 bp and was uninterrupted, encoding a polypeptide of 352 amino acids having 85% identity with the microsomal omega-6 desaturase GmFAD2-3 in soybean. PlFAD3 ORF had 1,116 bp and seven introns, encoding a polypeptide of 371 amino acids showing 91% homology with the microsomal omega-3 desaturase FAD3 in cowpea. PlSAD and PlFAD2 were expressed highly in leaves but poorly in roots and stems, while PlFAD3 was expressed in three tissues. All three genes were significantly induced in leaves by drought. PlSAD and PlFAD3 in leaves were down-regulated by high temperature and salinity, whereas PlFAD2 was up-regulated by the two stresses. The expression patterns of the three genes in lima bean leaves under suboptimal temperature, 18°C, were different from those under 8°C. The down-regulation of PlSAD transcript at chilling temperature might be an important factor contributing to chilling susceptibility for lima bean plants.

A rainbow coalition of lipid transcriptional regulators

Lipids are essential structural constituents of bacterial cell membranes and walls, and their biosynthetic pathways are stringently regulated at both biochemical and genetic levels. The recent surge of new information about transcriptional regulation of bacterial lipid metabolism is highlighted by two studies in this issue of Molecular Microbiology by Hugo Gramajo's research group, who add two transcription factors to the diverse repertoire of lipid biosynthesis regulators. FasR is a Streptomyces coelicolor transcriptional activator of genes in fatty acid synthesis, which supplies substrates for membrane phospholipid and triglyceride storage droplets. MabR is a regulator in Mycobacterium tuberculosis that functions as a repressor of essential genes in the cell wall mycolic acid biosynthetic pathway. MabR also affects the expression of fas, which encodes the multifunctional fatty acid synthase that supports phospholipid and triglyceride synthesis. Despite belonging to the same protein family, the distinct ligand binding domains of FasR and MabR suggest different ligands may regulate their DNA binding. The characterization of FasR/MabR exemplifies the structural and functional diversity of the rainbow coalition of lipid transcriptional regulators that reflects the diverse life styles of bacteria.

Life history and life tables of Bactericera cockerelli (Hemiptera: Psyllidae) on potato under laboratory and field conditions in the lower Rio Grande Valley of Texas

Effective management of potato 'Zebra Chip' (ZC) disease caused by Cadidatus Liberibacter psyllaurous (syn. solanacearum) depends on the management of its insect vector insect, potato psyllid, Bactericera cockerelli (Sulc) (Hemiptera: Psyllidae). To elucidate the age-specific population dynamics of B. cockerelli, the life-table parameters were determined on potato, Solanum tuberosum L., under both laboratory and field conditions in the Lower Rio Grande Valley (LRGV) of Texas. Generally, survival, fecundity, and longevity of B. cockerelli were significantly greater under laboratory than under field conditions. The mortality under laboratory conditions was mainly due to natural intrinsic mortality. However, under field conditions, most (83.2%) B. cockerelli were missing, and of those that were not, they developed slower, and had shorter preoviposition period, shorter oviposition period, shorter longevity, lower fecundity, and higher mortality than those under laboratory conditions. As a result, most of the life-table parameters of B. cockerelli, including the intrinsic rate of increase, finite rate of increase, and net reproductive rate, were significantly lower in the field under the environmental conditions of the LRGV of Texas than in the laboratory. The information could help increase our understanding of the epidemiology of the ZC diseases associated with the pathogens transmitted by this insect pest.

Advances in understanding the relationship between Toll-like receptors and digestive system injury

Toll-like receptors (TLRs) are cell-surface molecules that play an important role in the host immune response. More and more evidence indicates that TLRs can recognize special pattern molecules to activate certain signal transduction pathways and result in the release of numerous inflammatory mediators and active substances to induce digestive system injury, such as Helicobacter pylori infection-induced gastric mucosal injury, alcohol-induced gastritis, alcohol-induced liver injury, acute hemorrhagic necrotizing pancreatitis, hepatic ischemia-reperfusion injury (I/RI), and dextran sodium sulfate (DSS)-induced colitis. Here, we review the advances in understanding the relationship between TLRs and digestive system injury and explore the clinical value of TLRs in the diagnosis and treatment of digestive system diseases.

The protective effect of 17beta-estradiol postconditioning against hypoxia/reoxygenation injury in human gastric epithelial cells

The purpose of this study was to investigate the effects and mechanisms of 17beta-estradiol pharmacological postconditioning on gastric epithelial cells hypoxia/reoxygenation injury by using an in vitro model of human gastric epithelial cells. The model of hypoxia/reoxygenation was established with human gastric epithelial cell line. The gastric epithelial cell viability was detected by 3-(4, 5-dimethylthazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assays. Gastric epithelial cellular apoptosis was determined by Hoechst 33258 fluorochrome staining and flow cytometric analysis. Contents of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) were measured by Colorimetry analysis. The protein expression of Bcl-2 and Bax in different groups was determined by Western blot analyses and immunocytochemistry assay. 17beta-estradiol (10(-8), 10(-7) and 10(-6)mol/l) inhibited hypoxia/reoxygenation injury and 17beta-estradiol (10(-6)mol/l) obviously attenuated hypoxia/reoxygenation injury 3h hypoxia followed by 4h reoxygenation. 17beta-estradiol promoted gastric epithelial cell viability and inhibited the gastric epithelial cell apoptosis, and meanwhile, decreased the MDA content and increased SOD activity. The level of Bcl-2 protein was restored to the normal level by 17beta-estradiol pharmacological postconditioning. In contrast, the Bax protein level was markedly reduced by 17beta-estradiol pharmacological postconditioning. These effects of 17beta-estradiol were inhibited by pretreatment with fulvestrant. These data suggested that 17beta-estradiol seems involved in regulation of gastric hypoxia/reoxygenation injury and gastroprotection, and its protective effects were strongly related to estrogen receptor.

Structural basis for the transcriptional regulation of membrane lipid homeostasis

DesT is a transcriptional repressor that regulates the genes which control the unsaturated:saturated fatty acid ratio available for membrane lipid synthesis. DesT bound to unsaturated acyl-CoA has a high affinity for its cognate palindromic DNA-binding site, whereas DesT bound to saturated acyl-CoA does not bind to this site. Structural analyses of the DesT–oleoyl-CoA–DNA and DesT–palmitoyl-CoA complexes reveal that acyl chain shape directly influences the packing of hydrophobic core residues within the DesT ligand-binding domain. These changes are propagated to the paired DNA-binding domains via conformational changes to modulate DNA binding. These structural interpretations are supported by the in vitro and in vivo characterization of site-directed mutants. The regulation of DesT by the unsaturated:saturated ratio of acyl chains rather than the concentration of a single ligand is a paradigm for understanding transcriptional regulation of membrane lipid homeostasis.

Lipoxin A(4) inhibits transition of epithelial to mesenchymal cells in proximal tubules

BACKGROUND

Previous studies showed that connective tissue growth factor (CTGF)-induced proliferation of lung fibroblasts and production of chemokines in mesangial cells could be inhibited by lipoxin A(4) (LXA(4)). It is speculated that LXA(4) could modulate the CTGF-induced epithelial to mesenchymal transition.

METHODS

The expressions of alpha-smooth muscle actin (alpha-SMA), E-cadherin, integrin-linked kinase (ILK), extracellular signal-regulated kinase 1/2 (ERK1/2), phosphatidylinositol 3-kinase (PI3-K), Akt and Smad signaling were assessed by Western blot and/or real-time RT-PCR, and activation of Ras or ILK by activity assay, expressions of alpha-SMA and zonula occludens-1 by immunofluorescence assay in proximal tubular epithelial cells (HK-2).

RESULTS

Pretreatment of HK-2 cells with LXA(4) inhibited the morphological fibroblast-like changes and alpha-SMA expression induced by CTGF but not by transforming growth factor-beta(1) (TGF-beta(1)). The expressions of E-cadherin and zonula occludens-1 reduced by CTGF but not by TGF-beta(1) were increased by LXA(4). LXA(4) inhibited the expression and activity of ILK and activation of Ras, ERK1/2, PI3-K and Akt in HK-2 cells stimulated by CTGF. LXA(4) did not affect TGF-beta(1)-induced expression of ILK, Smad-2/3 phosphorylation and Smad-2's binding to Smad-4 and subsequent nuclear translocation.

CONCLUSION

LXA(4) inhibits the tubular epithelial to mesenchymal transition, initiated by CTGF but not by TGF-beta(1), via downregulation of ILK, Ras/MEK/ERK1/2 and PI3-K/Akt-dependent signal pathway stimulated by CTGF.

[Leber's hereditary optic neuropathy may be associated with the mitochondrial tRNAGlu A14693G mutation in three Chinese families]

We reported here the clinical, genetic and molecular characterization of three Han Chinese families with Leber's hereditary optic neuropathy. Ophthalmologic examinations revealed the variable severity and age-at-onset of visual loss among probands and other matrilineal relatives of these families. Strikingly, these families exhibited extremely low penetrances of visual impairment. Sequence analysis of complete mitochondrial genomes in these pedigrees identified the known homoplasmic tRNAGlu A14693G mutation and distinct sets of polymorphism belonging to haplogroups Y1b, Y1 and Y1, respectively. The A14693G mutation occurs at the extremely conserved nucleotide (conventional position 54) of tRNAGlu. Thus, this mutation may alter structural formation and stabilization of functional tRNAs, thereby leading to a failure in tRNA metabolism and mitochondrial dysfunction involved in visual impairment. However, none of other variants showed the evolutionary conservation and functional significance. These observations suggested that the tRNAGlu A14693G mutation may be involved in the pathogenesis of optic neuropathy in these families.

Reversed changes of lipoxin A4 and leukotrienes in children with asthma in different severity degree

OBJECTIVES

To investigate the expressions of 15-lipoxygenase (15-LO) and 5-lipoxygenase (5-LO) in leukocytes and the changes of blood lipoxin A(4)(LXA(4)), leukotriene (LT)B(4) and LTC(4) in children with asthma, and to explore the relationship between the blood eicosanoids and one of serum high-sensitivity C-reactive protein (hsCRP), interleukin (IL)-5, IL-8 and IL-13 and IgE in children with asthma.

STUDY DESIGN

One hundred six asthmatic children were divided into three groups, that is, mild persistent asthmatic group, moderate persistent asthmatic group and severe persistent asthmatic group. Forty healthy children were served as controls.

METHODOLOGY

The expressions of 15-LO and 5-LO mRNA in leukocytes were assessed by reverse transcription-polymerase chain reaction, and the blood LXA(4), LTB(4), LTC(4), IL-5, IL-8, and IL-13 were determined with enzyme-linked immunosorbent assay. Serum hsCRP was determined with latex-enhanced immuno-turbidimetry kits.

RESULTS

The leukocytic 15-LO expression and blood LXA(4) were gradually decreased, and the leukocytic 5-LO expression, blood LTB(4), LTC(4), IL-5, IL-8, IL-13, and hsCRP were gradually increased in children with asthma from mild degree to moderate and severe degree. There were positive correlations between blood LXA(4) and one of the peak expiratory flow (PEF) and forced expiratory volume in 1 sec (FEV(1)) percent-predicted values, and negative correlations between blood LTC(4) and one of the PEF and FEV(1) percent-predicted values in children with asthma. There were negative correlations between blood LXA(4) and one of the IL-5, IL-8, IL-13, and hsCRP levels, and positive correlations between one of blood LTB(4), LTC(4) and one of the IL-5, IL-8, IL-13 and hsCRP levels in children with asthma.

CONCLUSIONS

The reversed changes between 15-LO, its product LXA(4) and 5-LO, its products LTB(4) and LTC(4) in children with asthma from mild, moderate to severe degree were found, suggesting that insufficient generation of LXA(4) and overproduction of LTs may be the reason for the asthmatic children whose illness become more serious.

[Leber's hereditary optic neuropathy and limbs abnormity claudication may be associated with the mitochondrial ND1 T3866C mutation]

Mutations in mitochondrial DNA have been associated with a wide spectrum of clinical abnormalities. We reported here the clinical, genetic and molecular characterization of a five-generation Han Chinese pedigree with Leber's Hereditary Optic Neuropathy (LHON) and limbs abnormity claudication. Of 27 matrilineal relatives, four exhibited only LHON, one suffered from only limbs abnormity claudication, and four had both LHON and limbs abnormity claudication. Sequence analysis of mitochondrial genome in this family identified the known T3866C mutation in ND1 gene and other 43 variants belonging to the Asian haplogroup D4a3. The T3866C (I187T) mutation resulted in the replacement of isoleucine at position 187 with theronine. The isoleucine at position 187 located at one of transmembrane domain in ND1 polypeptide. The isoleucine at position 187 was extremely conserved among 29 organisms, while other variants showed no evolutionarily conservation. Furthermore, the T3866C was absence in 135 Chinese control subjects. The T3866C mutation likely alters the complex I activity, which causes mitochondrial dysfunction associated with LHON and limbs abnormity claudication. Therefore, the T3866C mutation is likely associated with LHON and limbs abnormity claudication.

Anticancer and antiradical scavenging activity of Ageratum conyzoides L. (Asteraceae)

Ageratum conyzoides has been used in folklore for the treatment of a wide range of diseases. In the present investigation, the in vitro activity of ethanol, petroleum ether, ethylacetate, butanol, and water extracts of A. conyzoides were screened in some cancer cell lines using the sulphorhodamine B (SRB) assay. These cell lines include: Human non-small cell lung carcinoma (A-549), human colon adenocarcinoma (HT-29), human gastric carcinoma (SGC-7901), human golima (U-251), human breast carcinoma (MDA-MB-231), human prostate carcinoma (DU-145), human hepatic carcinoma (BEL-7402), and mouse leukemia (P-388) cancer cell lines. Furthermore, kaempferol was isolated from the ethylacetate extract and the structure was elucidated by nuclear magnetic resonance (NMR) and mass spectroscopy. The effect of DPPH antiradical activity on the extracts and kaempferol was also determined. The results showed that ethylacetate extract exhibited the highest cytotoxic activity on A-549 and P-388 cancer cells with IC₅₀ values of 0.68 and 0.0003 μg/ml, respectively. Kaempferol isolated from the ethylacetate extract of A. conyzoides rapidly scavenged DPPH at a concentration of 130.07 ± 17.36 g/kg. The result therefore showed that A. conyzoides possessed anticancer and antiradical properties.

catena-Poly[[[aqua-silver(I)]-μ-4,4'-bipyridine-κN:N'] 4-amino-benzoate nitrate hydrate]

In the structure of the title compound, 2[Ag(C(10)H(8)N(2))(H(2)O)](C(7)H(6)NO(2))(NO(3))·H(2)O, the Ag(I) atom is three-coordinated in a T-shaped configuration by two N atoms from two symmetry-related 4,4'-bipyridine (bipy) ligands at short distances and by one water O atom at a longer distance. Each bipy ligand bridges two neighbouring Ag(I) atoms, forming a chain structure extending parallel to [101]. The complete 4-amino-benzoate anion, the nitrate anion and the uncoordinated water mol-ecule are located on mirror planes: together with the coordinated water mol-ecule, they form N-H⋯O, O-H⋯O and O-H⋯N hydrogen bonds, stabilizing the crystal structure.

DesT coordinates the expression of anaerobic and aerobic pathways for unsaturated fatty acid biosynthesis in Pseudomonas aeruginosa

The fabA and fabB genes are responsible for anaerobic unsaturated fatty acid formation in Pseudomonas aeruginosa. Expression of the fabAB operon was repressed by exogenous unsaturated fatty acids, and DNA sequences upstream of the translational start site were used to affinity purify DesT. The single protein interaction with the fabAB promoter detected in wild-type cell extracts was absent in the desT deletion strain, as was the repression of fabAB expression by unsaturated fatty acids. Thus, DesT senses the overall composition of the acyl-coenzyme A pool to coordinate the expression of the operons for the anaerobic (fabAB) and aerobic (desCB) pathways for unsaturated fatty acid synthesis.