Genetic diversity and geographic distribution of Bemisia tabaci and Trialeurodes vaporariorum in Costa Rica

The tobacco whitefly Bemisia tabaci (Gennadius) cryptic species complex and of the greenhouse whitefly Trialeurodes vaporariorum (Westwood) are extensively reported as destructive pests in vegetable crops worldwide. A survey was conducted in 2011 and 2012 to determine the occurrence and genetic diversity present in the populations of these whiteflies in the major vegetable production areas of Costa Rica. Insect samples were collected from sweet pepper (Capsicum annuum L.), tomato (Solanum lycopersicum L.), common bean (Phaseolus vulgaris L.) and weeds present in commercial crops either in open field or greenhouse conditions. PCR‐RFLP analysis of mitochondrial cytochrome c oxidase subunit 1 gene (mtCOI) sequences of 621 whitefly individuals confirmed the presence of the Mediterranean (MED) type of the B. tabaci and of T. vaporariorum in most sampled regions. Also, individuals of the Middle East‐Asia Minor 1 (MEAM1) type of the B. tabaci were observed in low numbers. Contingency analyses based on type of crop, geographical region, whitefly species, year of collection and production system confirmed that T. vaporariorum was the most frequent species in vegetable production areas in Costa Rica, both in greenhouses and in open fields. B. tabaci MED is likely spreading to new areas of the country, whereas B. tabaci MEAM1 was mostly absent or rarely found. Comparisons of mtCOI sequences from B. tabaci individuals revealed the presence of four B. tabaci sequence haplotypes (named MED‐i, MED‐ii, MEAM1‐i, MEAM1‐xviii) in Costa Rica, three of them identical to B. tabaci haplotypes previously reported in the Western Hemisphere and other parts of the world. Analysis of sequences of T. vaporariorum individuals revealed a more complex population with the presence of 11 haplotypes, two of which were identical to T. vaporariorum sequences reported from other countries.     

Temporal distribution of Chaetocnema pulicaria (Coleoptera: Chrysomelidae) populations in Iowa

In 1999 and 2000, yellow sticky cards and sweep net samples were used to document the occurrence of an overwintering adult generation of Chaetocnema pulicaria Melsheimer, corn flea beetle, followed by two distinct populations peaks during the growing season in Iowa Emergence of the overwintering adult generation started in mid-April and continued until early June in both years, with populations as high as 45 +/- 7.9 per 10 sweeps. Periods that ranged from 14 to 32 d were observed in 1999 and 2000 when C. pulicaria was not found following the overwintering generation. The first summer peak of C pulicaria was observed between the end of June into the middle of July, with the highest observed peak at 16.70 +/- 1.42 C. pulicaria per 10 sweeps in cornfields. The second summer peak of C pulicaria was observed between the middle into early September, with populations as high as 27.80 +/- 2.76 C. pulicaria per 10 sweeps. During the growing season, more C. pulicaria were caught on yellow sticky cards originating from soybean borders than from grass borders. There were significantly greater numbers of C. pulicaria on yellow sticky cards located in grass borders adjacent to cornfields at the end of the growing season, compared with yellow sticky cards located within cornfields, indicating the movement of C. pulicaria from the cornfield back into the grass borders at the end of the growing season. In 2000, from August to the end of the corn growing season, significantly more C. pulicaria were found in grass borders than in the cornfields. Based on this new quantitative information, planting time could be altered to avoid the emergence of the overwintering generation of C. pulicaria. In addition, knowledge concerning the seasonalities of the first and second population peaks of C pulicaria during the corn growing season could be used to recommend optimal timing for foliar-applied insecticide applications. This new knowledge concerning the seasonal dynamics of C pulicaria will help to improve management recommendations for Stewart's disease of corn, caused by the bacterium Pantoea stewartii, and that is vectored by C pulicaria.     

Binding Interactions of Keratin-Based Hair Fiber Extract to Gold,Keratin, and BMP-2

Hair-derived keratin biomaterials composed mostly of reduced keratin proteins (kerateines) have demonstrated their utility as carriers of biologics and drugs for tissue engineering. Electrostatic forces between negatively-charged keratins and biologic macromolecules allow for effective drug retention; attraction to positively-charged growth factors like bone morphogenetic protein 2 (BMP-2) has been used as a strategy for osteoinduction. In this study, the intermolecular surface and bulk interaction properties of kerateines were investigated. Thiol-rich kerateines were chemisorbed onto gold substrates to form an irreversible 2-nm rigid layer for surface plasmon resonance analysis. Kerateine-to-kerateine cohesion was observed in pH-neutral water with an equilibrium dissociation constant (K_D) of 1.8 × 10⁻⁴ M, indicating that non-coulombic attractive forces (i.e. hydrophobic and van der Waals) were at work. The association of BMP-2 to kerateine was found to be greater (K_D = 1.1 × 10⁻⁷ M), within the range of specific binding. Addition of salts (phosphate-buffered saline; PBS) shortened the Debye length or the electrostatic field influence which weakened the kerateine-BMP-2 binding (K_D = 3.2 × 10⁻⁵ M). BMP-2 in bulk kerateine gels provided a limited release in PBS (~ 10% dissociation in 4 weeks), suggesting that electrostatic intermolecular attraction was significant to retain BMP-2 within the keratin matrix. Complete dissociation between kerateine and BMP-2 occurred when the PBS pH was lowered (to 4.5), below the keratin isoelectric point of 5.3. This phenomenon can be attributed to the protonation of keratin at a lower pH, leading to positive-positive repulsion. Therefore, the dynamics of kerateine-BMP-2 binding is highly dependent on pH and salt concentration, as well as on BMP-2 solubility at different pH and molarity. The study findings may contribute to our understanding of the release kinetics of drugs from keratin biomaterials and allow for the development of better, more clinically relevant BMP-2-conjugated systems for bone repair and regeneration.     

Effect of neurotensin on pancreatic function in man

The effect of neurotensin on submaximally-stimulated hepatobiliary and pancreatic secretion was studied in 6 healthy subjects. An intravenous infusion of neurotensin 1.4 ± 0.3 pmol/kg/min, designed to reproduce plasma neurotensin immunoreactivity levels within the physiological range, produced a significant increase in pancreatic bicarbonate output. Plasma concentrations of pancreatic polypeptide rose by 83 ± 16 pmol/l and were associated with a small reduction in trypsin, but no significant change in bilirubin outputs.     

Comparing micellar, hemolytic, and antibacterial properties of di- and tricarboxyl dendritic amphiphiles

Homologous dicarboxyl dendritic amphiphiles-RCONHC(CH(3))(CH(2)CH(2)COOH)(2), 4(n); and ROCONHC(CH(3))(CH(2)CH(2)COOH)(2), 5(n), where R=n-C(n)H(2)(n)(+1) and n=13-22 carbon atoms-were synthesized. Critical micelle concentrations (CMCs) in aqueous triethanolamine solutions and at pH 7.4 were measured along with hemolytic activity (effective concentrations, EC(10)) in phosphate-buffered saline (PBS). LogCMC showed a linear dependence on chain length (n); the longest chain in each series had the lowest CMC-in triethanolamine: 4(21), 180μM and 5(22), 74μM and at pH 7.4: 4(21), 78μM and 5(22), 33μM. These two series, 4(n) and 5(n), and three series of homologous tricarboxyl dendritic amphiphiles-RCONHC(CH(2)CH(2)COOH)(3), 1(n); ROCONHC(CH(2)CH(2)COOH)(3), 2(n); RNHCONHC(CH(2)CH(2)COOH)(3), 3(n), where R=n-C(n)H(2)(n)(+1) and n=13-22 carbon atoms-were tested for growth inhibition of Staphylococcus aureus strain ATCC 6358 and methicillin-resistant S. aureus (MRSA) strain ATCC 43330 by microdilution in 0.1-strength brain heart infusion broth (BHIB). Amphiphiles 4(19), 4(21), 5(18), and 5(20) showed the strongest antibacterial activity (2.2-3.4μg/mL) against S. aureus (vancomycin, MIC=0.25μg/mL). These four plus 1(21), 2(20), 2(22), and 3(20) exhibited the strongest antibacterial activity (1.7-6.8μg/mL) against MRSA (vancomycin, MIC=0.25μg/mL). The MICs of these amphiphiles against six clinical MRSA were similar to those against the ATCC strain. In PBS, EC(10)s of the most active homologues ranged from 7 to 18μg/mL and 18 to 220μg/mL for di- and tricarboxyl dendritic amphiphiles, respectively. To assess the potential safety of using dendritic amphiphiles as drugs, measurements of micellar and hemolytic properties were conducted in the same medium (full-strength BHIB) that was used for antibacterial activity. The CMCs (9-36μg/mL, ～18-72μM) of ten amphiphiles were measured by microdilution (log2 progression) with dye-covered beads. The EC(10)s were similar to those in PBS. The MICs of most amphiphiles (14-72μg/mL) and vancomycin (1.1-2.2μg/mL) against both S. aureus and MRSA increased significantly compared to the MICs measured in 0.1-strength BHIB. The one exception, 5(18), had an MIC against S. aureus of 1.1μg/mL compared to vancomycin (2.2μg/mL). With CMC (9-18μg/mL) and EC(10) (16μg/mL) values higher than the MIC, 5(18) was discovered as a lead for further development.     

Seasonality of Rotifers and Temperature in Lough Neagh,N. Ireland

Long runs of seasonal rotifer population data allow analysis of seasonal occurrence using mathematical tools. The application of Fourier analysis to a 15 year dataset describes seasonality in simple mathematical terms. This facilitates comparison of population expression with potential population driving variables and provides a basic modelling tool. Results show that annual patterns of occurrence and density have linkages with annual maximum and minimum environmental temperature, although the exact relationships are not clear.     

Takayasu's arteritis is associated with HLA-B*52, but not with HLA-B*51, in Turkey

Introduction

HLA-B*51 and HLA-B*52 are two close human leukocyte antigen (HLA) allele groups with minor amino acid differences. However, they are associated with two different vasculitides (HLA-B*51 in Behçet's disease and HLA-B*52 in Takayasu's arteritis (TAK)) and with major clinical and immunological differences. In this study, we aimed to screen a large cohort of TAK patients from Turkey for the presence of HLA-B*51 and HLA-B*52 as susceptibility and severity factors.

Methods

TAK patients (n = 330) followed at a total of 15 centers were included in the study. The mean age of the patients was 37.8 years, and 86% were women. DNA samples from the patients and healthy controls (HC; n = 210) were isolated, and the presence of HLA-B*51 or HLA-B*52 was screened for by using PCR with sequence-specific primers.

Results

We found a significant association of HLA-B*52 with TAK (20.9% vs HC = 6.7%, P = 0.000, OR = 3.7, 95% CI = 2.02 to 6.77). The distribution of HLA-B*51 did not differ between TAK patients and HCs (22.7% vs 24.8%, OR = 0.9, 95% CI = 0.60 to 1.34). The presence of HLA-B*52 decreased in late-onset patients (> 40 years of age; 12.0%, P = 0.024, OR = 0.43, 95% CI = 0.20 to 0.91). Patients with angiographic type I disease with limited aortic involvement also had a lower presence of HLA-B*52 compared to those with all other disease subtypes (13.1% vs 26%, P = 0.005, OR = 0.43, 95% CI = 0.23 to 0.78).

Conclusions

In this study, the previously reported association of TAK with HLA-B*52 in other populations was confirmed in patients from Turkey. The functional relevance of HLA-B*52 in TAK pathogenesis needs to be explored further.