Tracing the origin of US brown marmorated stink bugs, Halyomorpha halys

Identifying the origin of a biological invasion has important applications to the effective control of the invaders. This is more critical for invasive agricultural pests that cause severe economic losses. The brown marmorated stink bug, Halyomorpha halys, originally from East Asia, has become a principal agricultural pest in the US since its first detection in Pennsylvania in 1996. This species is responsible for crop failures on many mid-Atlantic farms and current control efforts rely on heavy insecticide applications because no other options are available. To examine the genetic diversity and identify the source region of the US introductions, we sequenced portions of the mitochondrial cytochrome c oxidase subunit II gene, 12S ribosomal RNA gene and control region in populations from the US, China, South Korea and Japan. We detected high genetic divergence among native populations and traced the origin of US H. halys to the Beijing area in China. We observed much lower genetic diversity in exotic compared to native populations—two mitochondrial haplotypes in 55 US specimens versus 43 haplotypes in 77 native specimens. A single introduction of small propagule size matches the invasion history in the US. For the effective control of the US population, we suggest that surveys on egg parasitoids and insecticide resistance in natives should focus on the Beijing area in China.     

Toll-like receptor 4 mediates vascular remodeling in hyperhomocysteinemia

Nephrotic syndrome (NS) is a kidney disease predominantly present in children with idiopathic condition; final stage of the disease progresses into end-stage renal disease. Generally, NS is treated using standard steroid therapy, however; most of the children are steroid sensitive and about 15–20% are non-responders (SRNS). Non-responsiveness of these children would be a risk with the possibility of mutational changes in podocyte genes (NPHS1, NPHS2, WT1, PLCE1). The mutation in podocyte genes is associated with SRNS. NPHS1, NPHS2, and WT1 genes are identified/directly linked to SRNS. The present study is a surveillance on the mutation analysis of WT1 (exons 8 and 9) and NPHS2 (exons 1–8) gene in SRNS followed by clinical management. In the present study, we analyzed these two genes in a total of 117 SRNS (73 boys and 44 girls) children. A total of five mutations were detected in six children. First, WT1 mutation was detected at 9th intron-IVS 9 + 4C > T position in one SRNS female patient. This WT1 mutation was identified in a girl having Frasier Syndrome (FS) with focal segmental glomerulosclerosis and a complete sex reversal found through molecular and karyological screening. In NPHS2, missense mutations of P20L (in two children), P316S, and p.R229Q, and a frame shift mutation of 42delG were detected. Thus, applying molecular investigation helped us to decide on treatment plan of SRNS patients, mainly to avoid unnecessary immunosuppressive treatment.     

High efficiency electrotransformation of <Emphasis Type="Italic">Lactococcus lactis</Emphasis> spp. <Emphasis Type="Italic">lactis</Emphasis>cells pretreated with lithium acetate and dithiothreitol

Background  

A goal for the food industry has always been to improve strains of Lactococcus lactis and stabilize beneficial traits. Genetic engineering is used extensively for manipulating this lactic acid bacterium, while electropolation is the most widely used technique for introducing foreign DNA into cells. The efficiency of electrotransformation depends on the level of electropermealization and pretreatment with chemicals which alter cell wall permeability, resulting in improved transformation efficiencies is rather common practice in bacteria as in yeasts and fungi. In the present study, treatment with lithium acetate (LiAc) and dithiothreitol (DTT) in various combinations was applied to L. lactis spp. lactis cells of the early-log phase prior to electroporation with plasmid pTRKH3 (a 7.8 kb shuttle vector, suitable for cloning into L. lactis). Two strains of L. lactis spp. lactis were used, L. lactis spp. lactis LM0230 and ATCC 11454. To the best of our knowledge these agents have never been used before with L. lactis or other bacteria.     

D1S80 single-locus discrimination among African populations

The highly polymorphic D1S80 locus has no known genetic function. However, this variable number of tandem repeats (VNTR) locus has been highly valuable in forensic identification. In this study we report the allele and genotype frequencies of five African populations (Benin, Cameroon, Egypt, Kenya, and Rwanda), which can be used as databases to help characterize populations and identify individuals. The allele frequencies were used to infer genetic associations through phylogenetic, principal component, and G test statistical analyses. Compliance with Hardy-Weinberg equilibrium expectations was determined as were F(ST) estimates, theta p values, and power of discrimination assessment for each population. Our analyses of 28 additional populations demonstrate that the D1S80 locus alone can be used to discriminate geographic and ethnic groups. We have generated databases useful for human identification and phylogenetic studies.     

Profound Morphological Changes in the Erythrocytes and Fibrin Networks of Patients with Hemochromatosis or with Hyperferritinemia,and Their Normalization by Iron Chelators and Other Agents

It is well-known that individuals with increased iron levels are more prone to thrombotic diseases, mainly due to the presence of unliganded iron, and thereby the increased production of hydroxyl radicals. It is also known that erythrocytes (RBCs) may play an important role during thrombotic events. Therefore the purpose of the current study was to assess whether RBCs had an altered morphology in individuals with hereditary hemochromatosis (HH), as well as some who displayed hyperferritinemia (HF). Using scanning electron microscopy, we also assessed means by which the RBC and fibrin morphology might be normalized. An important objective was to test the hypothesis that the altered RBC morphology was due to the presence of excess unliganded iron by removing it through chelation. Very striking differences were observed, in that the erythrocytes from HH and HF individuals were distorted and had a much greater axial ratio compared to that accompanying the discoid appearance seen in the normal samples. The response to thrombin, and the appearance of a platelet-rich plasma smear, were also markedly different. These differences could largely be reversed by the iron chelator desferal and to some degree by the iron chelator clioquinol, or by the free radical trapping agents salicylate or selenite (that may themselves also be iron chelators). These findings are consistent with the view that the aberrant morphology of the HH and HF erythrocytes is caused, at least in part, by unliganded (‘free’) iron, whether derived directly via raised ferritin levels or otherwise, and that lowering it or affecting the consequences of its action may be of therapeutic benefit. The findings also bear on the question of the extent to which accepting blood donations from HH individuals may be desirable or otherwise.     

Myoglobin discriminates between O2, NO, and CO by electrostatic interactions with the bound ligand

 Most biological substrates have distinctive sizes, shapes, and charge distributions which can be recognized specifically by proteins. In contrast, myoglobin must discriminate between the diatomic gases O₂, CO, and NO which are apolar and virtually the same size. Selectivity occurs at the level of the covalent Fe-ligand complexes, which exhibit markedly different bond strengths and electrostatic properties. By pulling a water molecule into the distal pocket, His64(E7)¹ inhibits the binding of all three ligands by a factor of ∼10 compared to that observed for protoheme-imidazole complexes in organic solvents. In the case of O₂ binding, this unfavorable effect is overcome by the formation of a strong hydrogen bond between His64(E7) and the highly polar FeO₂ complex. This favorable electrostatic interaction stabilizes the bound O₂ by a factor of ∼1000, and the net result is a 100-fold increase in overall affinity compared to model hemes or mutants with an apolar residue at position 64. Electrostatic interaction between FeCO and His64 is very weak, resulting in only a two- to three-fold stabilization of the bound state. In this case, the inhibitory effect of distal pocket water dominates, and a net fivefold reduction in K _CO is observed for the wild-type protein compared to mutants with an apolar residue at position 64. Bound NO is stabilized ∼tenfold by hydrogen bonding to His64. This favorable interaction with FeNO exactly compensates for the tenfold inhibition due to the presence of distal pocket water, and the net result is little change in K _NO when the distal histidine is replaced with apolar residues. Thus, it is the polarity of His64 which allows discrimination between the diatomic gases. Direct steric hindrance by this residue plays a minor role as judged by: (1) the independence of K _O2, K _CO, and K _NO on the size of apolar residues inserted at position 64, and (2) the observation of small decreases, not increases, in CO affinity when the mobility of the His64 side chain is increased. Val68(E11) does appear to hinder selectively the binding of CO. However, the extent is no more than a factor of 2–5, and much smaller than electrostatic stabilization of bound O₂ by the distal histidine. Received, accepted: 23 May 1997     

Preparation and biological activity of taxol acetates

Synthesis and biological activity of 2′-acetyltaxol and 7-acetyltaxol are reported. Activity is measured $\text{in}\text{vivo}$ by cytotoxicity toward the macrophage-like cell line J774.2, and $\text{in}\text{vitro}$ by promotion of microtubule assembly in the absence of exogenous GTP. Addition of an acetyl moiety at C-2′ results in loss of $\text{in}\text{vitro}$ activity but not cytotoxicity. The properties of 7-acetyltaxol are similar to those of taxol in its effects on cell replication and on $\text{in}\text{vitro}$ microtubule polymerization. Therefore a free hydroxyl group at C-7 is not required for $\text{in}\text{vitro}$ activity and this position is available for structural modifications.     

Cost-Effectiveness and Efficacy of spa,SCCmec, and PVL Genotyping of Methicillin-Resistant Staphylococcus aureus as Compared to Pulsed-Field Gel Electrophoresis

Pulsed-field gel electrophoresis (PFGE) is a valuable molecular typing assay used for methicillin-resistant Staphylococcus aureus (MRSA) surveillance and genotyping. However, there are several limitations associated with PFGE. In Alberta, Canada, the significant increase in the number of MRSA isolates submitted to the Provincial Laboratory for Public Health (ProvLab) for PFGE typing led to the need for an alternative genotyping method. In this study, we describe the transition from PFGE to Staphylococcus protein A (spa), Staphylococcal cassette chromosome (SCCmec), and Panton-Valentine leukocidin (PVL) typing. A total of 1915 clinical MRSA isolates collected from 2005 to 2009 were used to develop and validate an algorithm for assigning PFGE epidemic types using spa, SCCmec, and PVL typing and the resulting data was used to populate a new Alberta MRSA typing database. An additional 12620 clinical MRSA isolates collected from 2010 to 2012 as part of ongoing routine molecular testing at ProvLab were characterized using the new typing algorithm and the Alberta MRSA typing database. Switching to spa, SCCmec, and PVL from PFGE typing substantially reduced hands-on and turn-around times while maintaining historical PFGE epidemic type designations. This led to an approximate $77,000 reduction in costs from 2010 to 2012. PFGE typing is still required for a small subset of MRSA isolates that have spa types that are rare, novel, or associated with more than one PFGE epidemic type.