Genetic analysis of emerald ash borer (<Emphasis Type="Italic">Agrilus planipennis</Emphasis> Fairmaire) populations in Asia and North America

Emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is an invasive pest of North American ash (Fraxinus spp.) trees first discovered outside of its native range of northeastern Asia in 2002. EAB spread from its initial zone of discovery in the Detroit, Michigan and Windsor, Ontario metropolitan areas, in large part, from inadvertent human-assisted movement of infested ash materials. EAB infestations are now known in 15 US states and two Canadian provinces. The primary goal of this study was to use molecular markers to characterize the population genetic structure of EAB in its native and introduced range. This information may provide valuable insights on the geographic origin, potential host range, invasion potential, and additional biological control agents for ongoing management efforts of this destructive wood-boring beetle. EAB were collected from 17 localities in its native Asian range and from 7 localities in North America, and population structure analyzed using mtDNA gene sequences, AFLP fingerprints, and alleles at 2 microsatellite loci. Analysis of mtDNA cytochrome oxidase subunit I gene (COI; 439 bp) sequences revealed all North American individuals carry a common mtDNA haplotype also found in China and South Korea. Additional mtDNA haplotypes observed in China and South Korea differed from the common haplotype by 1–2 nucleotide substitutions and a single individual from Japan differed by 21 nucleotide changes (4.8%). Analysis using AFLP fingerprints (108 loci) indicated Asian populations were more highly variable, yet had less overall population structure, than the North American populations. North American populations appear most closely related to populations in our sample from the Chinese provinces of Hebei and Tianjin City. Further, population assignment tests assigned 88% of the individual beetles from North America to either Hebei or Tianjin City.     

Tactics for management of thrips (Thysanoptera: Thripidae) and tomato spotted wilt virus in tomato

Four studies were conducted in Georgia during spring 1999, 2000, 2001, and 2002 to evaluate various management tactics for reducing thrips and thrips-vectored tomato spotted wilt virus (TSWV) in tomato and their interactions relative to fruit yield. Populations of thrips vectors of TSWV, Frankliniella occidentalis (Pergande) and Frankliniella fusca (Hinds), were determined using flower and sticky trap samples. The management practices evaluated were host plant resistance, insecticide treatments, and silver or metallic reflective mulch. Averaged over all tests, the TSWV-resistant tomato 'BHN444' on silver mulch treatment had the largest effect in terms of reducing thrips and spotted wilt and increasing marketable yield. Of the insecticide treatments tested, the imidacloprid soil treatment followed by early applications of a thrips-effective foliar insecticide treatment provided significant increase in yield over other treatments. Tomato yield was negatively correlated with the number of F. fusca and percentage of TSWV incidence. F. occidentalis per blossom was positively correlated with percentage of TSWV incidence, but not with yield. No significant interactions were observed between cultivar reflective mulch main plot treatments and insecticide subplot treatments; thus, treatment seemed to be additive in reducing the economic impact of thrips-vectored TSWV. Control tactics that manage thrips early in the growing season significantly increased tomato yield in years when the incidence of TSWV was high (>17%).     

Preliminary Assessment of Gastrointestinal Parasites in Two Wild Groups of Endangered Moor Macaques (Macaca maura) from Sulawesi

International Journal of Primatology - Information on parasite biodiversity and abundance can improve our understanding of parasitic infections on endangered wildlife, as parasites can affect host...     

Protein standard absolute quantification (PSAQ) method for the measurement of cellular ubiquitin pools

The protein ubiquitin is an important post-translational modifier that regulates a wide variety of biological processes. In cells, ubiquitin is apportioned among distinct pools, which include a variety of free and conjugated species. Although maintenance of a dynamic and complex equilibrium among ubiquitin pools is crucial for cell survival, the tools necessary to quantify each cellular ubiquitin pool have been limited. We have developed a quantitative mass spectrometry approach to measure cellular concentrations of ubiquitin species using isotope-labeled protein standards and applied it to characterize ubiquitin pools in cells and tissues. Our method is convenient, adaptable and should be a valuable tool to facilitate our understanding of this important signaling molecule.     

Identification of an interaction between the TPalpha and TPbeta isoforms of the human thromboxane A2 receptor with protein kinase C-related kinase (PRK) 1: implications for prostate cancer

In humans, thromboxane (TX) A(2) signals through the TPα and TPβ isoforms of the TXA(2) receptor or TP. Here, the RhoA effector protein kinase C-related kinase (PRK) 1 was identified as an interactant of both TPα and ΤPβ involving common and unique sequences within their respective C-terminal (C)-tail domains and the kinase domain of PRK1 (PRK1(640-942)). Although the interaction with PRK1 is constitutive, agonist activation of TPα/TPβ did not regulate the complex per se but enhanced PRK1 activation leading to phosphorylation of its general substrate histone H1 in vitro. Altered PRK1 and TP expression and signaling are increasingly implicated in certain neoplasms, particularly in androgen-associated prostate carcinomas. Agonist activation of TPα/TPβ led to phosphorylation of histone H3 at Thr(11) (H3 Thr(11)), a previously recognized specific marker of androgen-induced chromatin remodeling, in the prostate LNCaP and PC-3 cell lines but not in primary vascular smooth muscle or endothelial cells. Moreover, this effect was augmented by dihydrotestosterone in androgen-responsive LNCaP but not in nonresponsive PC-3 cells. Furthermore, PRK1 was confirmed to constitutively interact with TPα/TPβ in both LNCaP and PC-3 cells, and targeted disruption of PRK1 impaired TPα/TPβ-mediated H3 Thr(11) phosphorylation in, and cell migration of, both prostate cell types. Collectively, considering the role of TXA(2) as a potent mediator of RhoA signaling, the identification of PRK1 as a bona fide interactant of TPα/TPβ, and leading to H3 Thr(11) phosphorylation to regulate cell migration, has broad functional significance such as within the vasculature and in neoplasms in which both PRK1 and the TPs are increasingly implicated.     

Locational distribution of gene functional classes in <Emphasis Type="Italic">Arabidopsis thaliana</Emphasis>

Background  

We are interested in understanding the locational distribution of genes and their functions in genomes, as this distribution has both functional and evolutionary significance. Gene locational distribution is known to be affected by various evolutionary processes, with tandem duplication thought to be the main process producing clustering of homologous sequences. Recent research has found clustering of protein structural families in the human genome, even when genes identified as tandem duplicates have been removed from the data. However, this previous research was hindered as they were unable to analyse small sample sizes. This is a challenge for bioinformatics as more specific functional classes have fewer examples and conventional statistical analyses of these small data sets often produces unsatisfactory results.     

Cross-generational effect of prenatal morphine exposure on neurobehavioral development of rat pups

Prenatal exposure to opiates can have devastating effects on the development of human fetuses and may induce long-term physical and neurobehavioral changes during postnatal maturation. The present study was aimed at identifying cross-generational effects of prenatal morphine exposure in Sprague-Dawley rats. Pregnant rats were injected subcutaneously with either saline or morphine (10 mg/kg) twice daily during gestational days 11-18. Litter size, percentage of males and females, anogenital distances (AGDs), righting reflex, and body weight were assessed in prenatally morphine-exposed pups (first generation) and their offspring (second generation). Both prenatally morphine-exposed pups and offspring of prenatally morphine-exposed dams exhibited an increased latency to right. Additionally, second generation pups were slower in righting than first generation pups. During the early postnatal period the second generation pups weighed less than the first generation regardless of drug exposure. The AGDs of second generation male pups were decreased relative to the first generation. Our data provide important novel information about the trans-generational effects of maternal opiate abuse that may be useful for understanding/evaluating the teratogenic effects of prenatal opiate exposure.     

Indirect inhibition of 26S proteasome activity in a cellular model of Huntington's disease

Pathognomonic accumulation of ubiquitin (Ub) conjugates in human neurodegenerative diseases, such as Huntington's disease, suggests that highly aggregated proteins interfere with 26S proteasome activity. In this paper, we examine possible mechanisms by which an N-terminal fragment of mutant huntingtin (htt; N-htt) inhibits 26S function. We show that ubiquitinated N-htt-whether aggregated or not-did not choke or clog the proteasome. Both Ub-dependent and Ub-independent proteasome reporters accumulated when the concentration of mutant N-htt exceeded a solubility threshold, indicating that stabilization of 26S substrates is not linked to impaired Ub conjugation. Above this solubility threshold, mutant N-htt was rapidly recruited to cytoplasmic inclusions that were initially devoid of Ub. Although synthetically polyubiquitinated N-htt competed with other Ub conjugates for access to the proteasome, the vast majority of mutant N-htt in cells was not Ub conjugated. Our data confirm that proteasomes are not directly impaired by aggregated N-terminal fragments of htt; instead, our data suggest that Ub accumulation is linked to impaired function of the cellular proteostasis network.     

RNA-directed construction of structurally complex and active ligase ribozymes through recombination

RNA-directed recombination can be used to catalyze a disproportionation reaction among small RNA substrates to create new combinations of sequences. But the accommodation of secondary and tertiary structural constraints in the substrates by recombinase ribozymes has not been explored. Here, we show that the Azoarcus group I intron can recombine oligoribonucleotides to construct class I ligase ribozymes, which are catalytically active upon synthesis. The substrate oligonucleotides, ranging in size from 58 to 104 nucleotides (nt), along with the 152-nt ligase ribozymes they reconstitute, can contain significant amounts of secondary structure. However, substrate recognition by the Azoarcus ribozyme depends on the existence of a single accessible CAU triplet for effective recombination. A biphasic temperature reaction profile was designed such that the sequential recombination/ligation events could take place in a thermocycler without human intervention. A temperature-dependent pH shift of the reaction buffer contributes to the success of the net reaction. When the substrate for the ligase ribozyme is introduced into the reaction mixture, as much as 11% can be observed being converted to product by the recombined ligase in the same reaction vessel. Recombination followed by ligation can also occur under isothermal conditions at 37 degrees C. Tertiary structure formation of the ligase upon construction can provide some protection from cleavage by the Azoarcus ribozyme when compared to the constituent substrates. These data suggest that RNA-directed recombination can, in fact, articulate complex ribozymes, and that there are logical rules that can guide the optimal placement of the CAU recognition sequence.