High Frequency of Transmitted HIV-1 Gag HLA Class I-Driven Immune Escape Variants but Minimal Immune Selection over the First Year of Clade C Infection

In chronic HIV infection, CD8+ T cell responses to Gag are associated with lower viral loads, but longitudinal studies of HLA-restricted CD8+ T cell-driven selection pressure in Gag from the time of acute infection are limited. In this study we examined Gag sequence evolution over the first year of infection in 22 patients identified prior to seroconversion. A total of 310 and 337 full-length Gag sequences from the earliest available samples (median = 14 days after infection [Fiebig stage I/II]) and at one-year post infection respectively were generated. Six of 22 (27%) individuals were infected with multiple variants. There was a trend towards early intra-patient viral sequence diversity correlating with viral load set point (p = 0.07, r = 0.39). At 14 days post infection, 59.7% of Gag CTL epitopes contained non-consensus polymorphisms and over half of these (35.3%) comprised of previously described CTL escape variants. Consensus and variant CTL epitope proportions were equally distributed irrespective of the selecting host HLA allele and most epitopes remained unchanged over 12 months post infection. These data suggest that intrapatient diversity during acute infection is an indicator of disease outcome. In this setting, there is a high rate of transmitted CTL escape variants and limited immune selection in Gag during the first year of infection. These data have relevance for vaccine strategies designed to elicit effective CD8+ T cell immune responses.     

Identification of gastrin molecular variants in gastrinoma syndrome

The molecular species of gastrin in the circulation and in tumor extracts were studied in two groups of patients: (1) with benign gastrinoma and (2) with gastrinoma with liver metastases. Radioimmunoassays (RIAs) and immunoaffinity chromatography for the amino (NH2)- and amidated COOH-terminus of gastrin-17 (antiserum G17) and the NH2-terminus of gastrin-34 (antiserum G34) were employed. In both benign and metastatic tumors the molecular forms of gastrin in boiling water extracts measured by the gastrin-17 NH2- and COOH-terminal assays were similar. In addition to a molecular component resembling the amidated gastrin-17, there were also significant amounts of larger molecular weight (mol. wt.) forms. The larger mol. wt. forms absorbed by the NH2-terminus of G17 antiserum corresponded to the COOH-terminus-extended forms of gastrin-17. Furthermore, larger mol. wt. gastrins immunopurified by antiserum to the NH2-terminus of gastrin-34 corresponded to gastrin-34 extended molecules. Sera of patients with liver metastases had higher concentrations of the NH2-terminal of gastrin-17 whereas sera of patients with benign gastrinoma contained predominantly gastrins detected by the COOH-terminal assay. These results suggest that: (a) there are differences in the molecular pattern of gastrin in the circulation of patients with benign and metastatic gastrinomas; (b) gastrins which are fully processed with carboxy-terminal amidation predominate in the circulation of patients with benign gastrinoma; and (c) gastrins containing the gastrin-17 and COOH-terminally extended gastrin-17 and gastrin-34 precursor molecules occur in high concentration in the circulation of gastrinoma patients with metastases to the liver.     

The Vesicle Protein SAM-4 Regulates the Processivity of Synaptic Vesicle Transport

Axonal transport of synaptic vesicles (SVs) is a KIF1A/UNC-104 mediated process critical for synapse development and maintenance yet little is known of how SV transport is regulated. Using C. elegans as an in vivo model, we identified SAM-4 as a novel conserved vesicular component regulating SV transport. Processivity, but not velocity, of SV transport was reduced in sam-4 mutants. sam-4 displayed strong genetic interactions with mutations in the cargo binding but not the motor domain of unc-104. Gain-of-function mutations in the unc-104 motor domain, identified in this study, suppress the sam-4 defects by increasing processivity of the SV transport. Genetic analyses suggest that SAM-4, SYD-2/liprin-α and the KIF1A/UNC-104 motor function in the same pathway to regulate SV transport. Our data support a model in which the SV protein SAM-4 regulates the processivity of SV transport.     

Inhibition of Aflatoxin Production by Surfactants

The effect of 12 surfactants on aflatoxin production, growth, and conidial germination by the fungus Aspergillus flavus is reported. Five nonionic surfactants, Triton X-100, Tergitol NP-7, Tergitol NP-10, polyoxyethylene (POE) 10 lauryl ether, and Latron AG-98, reduced aflatoxin production by 96 to 99% at 1% (wt/vol). Colony growth was restricted by the five nonionic surfactants at this concentration. Aflatoxin production was inhibited 31 to 53% by lower concentrations of Triton X-100 (0.001 to 0.0001%) at which colony growth was not affected. Triton X-301, a POE-derived anionic surfactant, had an effect on colony growth and aflatoxin production similar to that of the five POE-derived nonionic surfactants. Sodium dodecyl sulfate (SDS), an anionic surfactant, and dodecyltrimethylammonium bromide, a cationic surfactant, suppressed conidial germination at 1% (wt/vol). SDS had no effect on aflatoxin production or colony growth at 0.001%. The degree of aflatoxin inhibition by a surfactant appears to be a function of the length of the hydrophobic and hydrophilic chains of POE-derived surfactants.     

Soybean Aphid Response to their Alarm Pheromone E-ß-Farnesene (EBF)

When attacked by natural enemies some insect pests, including many aphid species, alert neighboring conspecifics with alarm pheromones. Cornicle secretions with pheromones benefit the attacked aphid but are costly to produce, while alarm pheromone benefits probably fall largely on alerted conspecifics. Given these variable benefits, the likelihood of a secretion may change depending on aphid density. Thus, we first hypothesized that the common alarm pheromone in aphids, E-ß-farnesene (EBF), was present in soybean aphid (Aphis glycines Matsumura) cornicle secretions and would elicit an alarm response in aphids exposed to it. Second, since aphids other than the secretor also benefit from cornicle secretions, we hypothesized that the likelihood of secretion would increase concurrently with the density of neighboring clonal conspecifics. Third, because alarm reaction behavior (e.g. feeding cessation) is probably costly, we hypothesized that alarm reaction behavior would decrease as conspecific density (i.e. alternative prey for an attacking natural enemy) increased. We found that soybean aphids 1) produce cornicle secretions using EBF as an alarm pheromone, 2) are less likely to release cornicle secretions when alone than in a small group (~10 individuals), but that the rate of secretion does not increase further with additional conspecific density, and 3) also exhibit alarm reaction behavior in response to cornicle secretions independent of aphid density. We show that soybean aphids can use their cornicle secretions to warn their neighbors of probable attack by natural enemies, but that both secretion and alarm reaction behavior does not change as density of nearby conspecifics rises above a few individuals.     

Aflatoxin variability in pistachios.

Pistachio fruit components, including hulls (mesocarps and epicarps), seed coats (testas), and kernels (seeds), all contribute to variable aflatoxin content in pistachios. Fresh pistachio kernels were individually inoculated with Aspergillus flavus and incubated 7 or 10 days. Hulled, shelled kernels were either left intact or wounded prior to inoculation. Wounded kernels, with or without the seed coat, were readily colonized by A. flavus and after 10 days of incubation contained 37 times more aflatoxin than similarly treated unwounded kernels. The aflatoxin levels in the individual wounded pistachios were highly variable. Neither fungal colonization nor aflatoxin was detected in intact kernels without seed coats. Intact kernels with seed coats had limited fungal colonization and low aflatoxin concentrations compared with their wounded counterparts. Despite substantial fungal colonization of wounded hulls, aflatoxin was not detected in hulls. Aflatoxin levels were significantly lower in wounded kernels with hulls than in kernels of hulled pistachios. Both the seed coat and a water-soluble extract of hulls suppressed aflatoxin production by A. flavus.     

Roles of mouse sperm‐associated alpha‐L‐fucosidases in fertilization

Sperm‐associated α‐L ‐fucosidases have been implicated in fertilization in many species. Previously, we documented the existence of α‐L ‐fucosidase in mouse cauda epididymal contents, and showed that sperm‐associated α‐L ‐fucosidase is cryptically stored within the acrosome and reappears within the sperm equatorial segment after the acrosome reaction. The enrichment of sperm membrane‐associated α‐L ‐fucosidase within the equatorial segment of acrosome‐reacted cells implicates its roles during fertilization. Here, we document the absence of α‐L ‐fucosidase in mouse oocytes and early embryos, and define roles of sperm associated α‐L ‐fucosidase in fertilization using specific inhibitors and competitors. Mouse sperm were pretreated with deoxyfuconojirimycin (DFJ, an inhibitor of α‐L ‐fucosidase) or with anti‐fucosidase antibody; alternatively, mouse oocytes were pretreated with purified human liver α‐L ‐fucosidase. Five‐millimolar DFJ did not inhibit sperm–zona pellucida (ZP) binding, membrane binding, or fusion and penetration, but anti‐fucosidase antibody and purified human liver α‐L ‐fucosidase significantly decreased the frequency of these events. To evaluate sperm‐associated α‐L ‐fucosidase enzyme activity in post‐fusion events, DFJ‐pretreated sperm were microinjected into oocytes, and 2‐pronuclear (2‐PN) embryos were treated with 5 mM DFJ with no significant effects, suggesting that α‐L ‐fucosidase enzyme activity does not play a role in post‐fusion events and/or early embryo development in mice. The recognition and binding of mouse sperm to the ZP and oolemma involves the glycoprotein structure of α‐L ‐fucosidase, but not its catalytic action. These observations suggest that deficits in fucosidase protein and/or the presence of anti‐fucosidase antibody may be responsible for some types of infertility. Mol. Reprod. Dev. 80: 273–285, 2013. © 2013 Wiley Periodicals, Inc.     

A variant in ANKK1 modulates acute subjective effects of cocaine: a preliminary study

This study aimed to evaluate whether functional variants in the ankyrin repeat and kinase domain‐containing 1 (ANKK1) gene and/or the dopamine receptor D2 (DRD2) gene modulate the subjective effects (reward or non‐reward response to a stimulus) produced by cocaine administration. Cocaine‐dependent participants (N = 47) were administered 40 mg of cocaine or placebo at time 0, and a subjective effects questionnaire (visual analog scale) was administered 15 min prior to cocaine administration, and at 5, 10, 15 and 20 min following administration. The influence of polymorphisms in the ANKK1 and DRD2 genes on subjective experience of cocaine in the laboratory was tested. Participants with a T allele of ANKK1 rs1800497 experienced greater subjective ‘high’ (P = 0.00006), ‘any drug effect’ (P = 0.0003) and ‘like’ (P = 0.0004) relative to the CC genotype group. Although the variant in the DRD2 gene was shown to be associated with subjective effects, linkage disequilibrium analysis revealed that this association was driven by the ANKK1 rs1800497 variant. A participant's ANKK1 genotype may identify individuals who are likely to experience greater positive subjective effects following cocaine exposure, including greater ‘high’ and ‘like’, and these individuals may have increased vulnerability to continue using cocaine or they may be at greater risk to relapse during periods of abstinence. However, these results are preliminary and replication is necessary to confirm these findings.     

Discrimination between Francisella tularensis and Francisella-Like Endosymbionts when Screening Ticks by PCR

The presence of Francisella-like endosymbionts in tick species known to transmit tularemia poses a potential diagnostic problem for laboratories that screen tick samples by PCR for Francisella tularensis. Tick samples initially considered positive for F. tularensis based on standard 16S rRNA gene PCR were found to be positive only for Francisella-like endosymbionts using a multitarget F. tularensis TaqMan assay (ISFtu2, tul4, and iglC) and 16S rRNA gene sequencing. Specificity of PCR-based diagnostics for F. tularensis should be carefully evaluated with appropriate specimen types prior to diagnostic use.     

Selection for genetics‐based architecture traits in a native cottonwood negatively affects invasive tamarisk in a restoration field trial

Climate change and competition from invasive species remain two important challenges in restoration. We examined the hypothesis that non‐native tamarisk (Tamarix spp.) reestablishment after aboveground removal is affected by genetics‐based architecture of native Fremont cottonwood (Populus fremontii) used in restoration. As cottonwood architecture (height, canopy width, number of stems, and trunk diameter) is, in part, determined by genetics, we predicted that trees from different provenances would exhibit different architecture, and mean annual maximum temperature transfer distance from the provenances would interact with the architecture to affect tamarisk. In a common garden in Chevelon, AZ, U.S.A. (elevation 1,496 m), with cottonwoods from provenances spanning its elevation distribution, we measured the performance of both cottonwoods and tamarisk. Several key findings emerged. On average, cottonwoods from higher elevations were (1) two times taller and wider, covered approximately 3.5 times more basal area, and were less shrubby in appearance, by exhibiting four times fewer number of stems than cottonwoods from lower elevations; (2) had 50% fewer tamarisk growing underneath, which were two times shorter and covered 6.5 times less basal area than tamarisk growing underneath cottonwoods of smaller stature; and (3) the number of cottonwood stems did not affect tamarisk growth, possibly because the negative relationship between cottonwood stems and basal area. In combination, these findings argue that cottonwood architecture is affected by local conditions that interact with genetics‐based architecture. These interactions can negatively affect the growth of reinvading tamarisk and enhance restoration success. Our study emphasizes the importance of incorporating genetic and environmental interactions of plants used in restoration.