Integracides: tetracyclic triterpenoid inhibitors of HIV-1 integrase produced by Fusarium sp

HIV-1 integrase is a critical enzyme in the replication of HIV-1. It is absent in the host cells and therefore is a good target for treatment of HIV-1 infections. Integracides are members of the tetracyclic triterpenoids family that were isolated from the fermentation broth of a Fusarium sp. Integracide A, a sulfated ester, exhibited significant inhibitory activity against strand transfer reaction of HIV-1 integrase. The discovery, structure elucidation including single crystal X-ray structure and HIV-1 inhibitory activity of these compounds are described.     

Role of microglial cells in selective replication of simian immunodeficiency virus genotypes in the brain

An accelerated, consistent macaque simian immunodeficiency virus (SIV) model in which over 90% of pigtailed macaques (Macaca nemestrina) coinoculated with SIV/17E-Fr and SIV/DeltaB670 developed encephalitis was used to determine whether central nervous system (CNS) lesions are associated with the replication of specific genotypes in the brain and, more specifically, in the microglia. Ten of 11 inoculated macaques had severe (n = 3), moderate (n = 5), or mild (n = 2) encephalitis at 3 months postinoculation. To compare actively replicating viral genotypes in the CNS and in microglia with those in the periphery, the V1 region of the SIV envelope gene was amplified and sequenced from RNA extracted from basal ganglia, from microglial cells isolated from the brain, and from peripheral blood mononuclear cells (PBMC) isolated from blood at the time of death. To distinguish between actively replicating with latent viral genotypes in the CNS, viral genotypes in RNA and DNA from basal ganglia were compared. Two macrophage-tropic, neurovirulent viruses, SIV/17E-Fr and SIV/DeltaB670 Cl-2, predominated in the brain RNA of macaques with encephalitis, comprising 95% of the genotypes detected. The same two viral genotypes were present at the same frequencies in microglial cell RNA, suggesting that microglia are pivotal in the selective replication of neurovirulent viruses. There was a significantly greater number of viral genotypes in DNA than there were in RNA in the brain (P = 0.004), including those of both the macrophage- and lymphocyte-tropic viral strains. Furthermore, significantly fewer viral genotypes were detected in brain RNA than in PBMC RNA at the time of death (P = 0.004) and the viral strain that predominated in the brain frequently was different from that which predominated in the PBMC of the same animal. These data suggest that many viral genotypes enter the brain, but only a limited subset of macrophage-tropic, neurovirulent viruses replicate terminally in the brains of macaques with encephalitis. They further suggest that the selection of macrophage-tropic, neurovirulent viruses occurs not at the level of the blood-brain barrier but at a stage after virus entry and that microglial cells may play an important role in that selection process.     

A comparative electromyographical investigation of muscle utilization patterns using various hand positions during the lat pull-down

This study aimed at investigating the effects of different hand positions on the electromyographic (EMG) activity of shoulder muscles during the performance of the lat pull-down exercise. Ten healthy men performed 3 repetitions of the lat pull-down exercise using their experimentally determined 10RM (repetition maximum) weight. Four different common variations of the lat pull-down were used: close grip (CG), supinated grip (SG), wide grip anterior (WGA), and wide grip posterior (WGP). Normalized root mean square of the EMG (NrmsEMG) activity for the right posterior deltoid (PD), latissimus dorsi (LD), pectoralis major (PM), teres major (TM), and long head of the triceps (TLH) were recorded using surface electrodes and normalized using maximum voluntary contractions. Repeated measures analysis of variance for each muscle detected statistical differences (p < 0.05) in myoelectric activity among hand positions during both the concentric and eccentric phases of the exercise. During the concentric phase, NrmsEMG results for the LD included WGA > WGP, SG, CG. For the TLH: WGA > WGP, SG, CG and WGP > CG, SG. For the PD: CG, WGA, SG > WGP. For the PM: CG, WGA, SG > WGP. During the eccentric phase, the LD produced the following patterns: WGA > WGP, SG, CG and WGP > CG. The TLH pattern showed WGA > SG and CG. For the PD: CG > WGA, WGP. The results indicate that changes in handgrip position affect the activities of specific muscles during the lat pull-down movement. Also, performance of the lat pull-down exercise using the WGA hand position produces greater muscle activity in the LD than any other hand position during both the concentric or eccentric phases of the movement.     

Genetic diversity in Delphinium variegatum (Ranunculaceae): a comparison of two insular endemic subspecies and their widespread mainland relative

Delphinium variegatum is subdivided into three subspecies: D. v. variegatum is widespread in central and northern California, while D. v. kinkiense (an endangered taxon) and D. v. thornei are endemic to San Clemente Island off the coast of southern California. Electrophoretic data for 19 loci were collected from 7 populations of the mainland subspecies and all 24 known populations of the two insular endemic subspecies. Populations of the widespread mainland subspecies have more polymorphic loci (33.6% vs. 24.5%) and more alleles per polymorphic locus (2.61 vs. 2.15) than the insular endemic subspecies. However, observed heterozygosities are lower in the mainland subspecies (0.041 vs. 0.071), presumably due to lower levels of outcrossing (t = 0.464 vs. 0.895). Expected heterozygosities are similar (0.064 vs. 0.074) due to lower alternative allele frequencies in populations of the mainland subspecies (mean q = 0.075 vs. 0.190). Populations of the two insular subspecies are almost equivalent genetically (mean I = 0.997) regardless of taxonomic designation or geographic location. In contrast, one of the mainland populations is genetically well differentiated from the others. If this exceptional population is excluded, the mainland subspecies partitions genetic diversity similarly to the island subspecies, with most variation being found within populations (G(ST) = 0.073 vs. 0.030).     

12-lipoxygenase in porcine coronary microcirculation: implications for coronary vasoregulation

Noncyclooxygenase metabolites of arachidonic acid (AA) have been proposed to mediate endothelium-dependent vasodilation in the coronary microcirculation. Therefore, we examined the formation and bioactivity of AA metabolites in porcine coronary (PC) microvascular endothelial cells and microvessels, respectively. The major noncyclooxygenase metabolite produced by microvascular endothelial cells was 12(S)-hydroxyeicosatetraenoic acid (HETE), a lipoxygenase product. 12(S)-HETE release was markedly increased by pretreatment with 13(S)-hydroperoxyoctadecadienoic acid but not by the reduced congener 13(S)-hydroxyoctadecadienoic acid, suggesting oxidative upregulation of 12(S)-HETE output. 12(S)-HETE produced potent relaxation and hyperpolarization of PC microvessels (EC(50), expressed as -log[M] = 13.5 +/- 0.5). Moreover, 12(S)-HETE potently activated large-conductance Ca(2+)-activated K(+) currents in PC microvascular smooth muscle cells. In contrast, 12(S)-HETE was not a major product of conduit PC endothelial AA metabolism and did not exhibit potent bioactivity in conduit PC arteries. We suggest that, in the coronary microcirculation, 12(S)-HETE can function as a potent hyperpolarizing vasodilator that may contribute to endothelium-dependent relaxation, particularly in the setting of oxidative stress.     

The Evolution of Intraspecific Brood Parasitism in Birds and Insects

Many species of birds and insects engage in intraspecific brood parasitism (IBP), when a female lays eggs in the nest of a conspecific and leaves without providing parental care. These visiting females may also act to cooperate with a primary female, staying to provide parental care. Therefore, IBP and cooperative breeding can be considered extremes on a continuum of parental care provided by a secondary female. When a secondary female abandons a nest, she creates an asymmetry in parental care between herself and the host. While models of asymmetry in reproductive allocation have focused directly on relatedness between females, we lack an appropriate theoretical framework that addresses the effects of relatedness on parental care asymmetry. Here, I present an evolutionarily stable strategy (ESS) model that predicts the conditions under which IBP is favored over cooperation and solitary breeding. Intraspecific brood parasitism is less likely to evolve (relative to cooperation and solitary breeding) as the relatedness between a host and parasite increases. It can evolve, however, if parasites achieve a high overall fecundity relative to solitary females. Constraints on solitary breeding can further promote IBP under some circumstances. Cooperation is favored when relatedness is high and reproductive skew is low. This model makes several predictions regarding the conditions under which IBP may evolve, motivating a variety of experimental approaches.     

The comparative amino acid sequences, substrate specificities and gene or cDNA nucleotide sequences of some prokaryote and eukaryote amidinotransferases: implications for evolution

The amino acid sequences of the amidinotransferases and the nucleotide sequences of their genes or cDNA from four Streptomyces species (seven genes) and from the kidneys of rat, pig, human and human pancreas were compared. The overall amino acid and nucleotide sequences of the prokaryotes and eukaryotes were very similar and further, three regions were identified that were highly identical. Evidence is presented that there is virtually zero chance that the overall and high identity regions of the amino acid sequence similarities and the overall nucleotide sequence similarities between Streptomyces and mammals represent random match. Both rat and lamprey amidinotransferases were able to use inosamine phosphate, the amidine group acceptor of Streptomyces. We have concluded that the structure and function of the amidinotransferases and their genes has been highly conserved through evolution from prokaryotes to eukaryotes. The evolution has occurred with: (1) a high degree of retention of nucleotide and amino acid sequences; (2) a high degree of retention of the primitive Streptomyces guanine+cytosine (G+C) third codon position composition in certain high identity regions of the eukaryote cDNA; (3) a decrease in the specificities for the amidine group acceptors; and (4) most of the mutations silent in the regions suggested to code for active sites in the enzymes.     

Area-Specific Information Processing in Prefrontal Cortex during a Probabilistic Inference Task: A Multivariate fMRI BOLD Time Series Analysis

Introduction

Discriminating spatiotemporal stages of information processing involved in complex cognitive processes remains a challenge for neuroscience. This is especially so in prefrontal cortex whose subregions, such as the dorsolateral prefrontal (DLPFC), anterior cingulate (ACC) and orbitofrontal (OFC) cortices are known to have differentiable roles in cognition. Yet it is much less clear how these subregions contribute to different cognitive processes required by a given task. To investigate this, we use functional MRI data recorded from a group of healthy adults during a “Jumping to Conclusions” probabilistic reasoning task.

Methods

We used a novel approach combining multivariate test statistics with bootstrap-based procedures to discriminate between different task stages reflected in the fMRI blood oxygenation level dependent signal pattern and to unravel differences in task-related information encoded by these regions. Furthermore, we implemented a new feature extraction algorithm that selects voxels from any set of brain regions that are jointly maximally predictive about specific task stages.

Results

Using both the multivariate statistics approach and the algorithm that searches for maximally informative voxels we show that during the Jumping to Conclusions task, the DLPFC and ACC contribute more to the decision making phase comprising the accumulation of evidence and probabilistic reasoning, while the OFC is more involved in choice evaluation and uncertainty feedback. Moreover, we show that in presumably non-task-related regions (temporal cortices) all information there was about task processing could be extracted from just one voxel (indicating the unspecific nature of that information), while for prefrontal areas a wider multivariate pattern of activity was maximally informative.

Conclusions/Significance

We present a new approach to reveal the different roles of brain regions during the processing of one task from multivariate activity patterns measured by fMRI. This method can be a valuable tool to assess how area-specific processing is altered in psychiatric disorders such as schizophrenia, and in healthy subjects carrying different genetic polymorphisms.     

The Drosophila neural lineages: a model system to study brain development and circuitry

In Drosophila, neurons of the central nervous system are grouped into units called lineages. Each lineage contains cells derived from a single neuroblast. Due to its clonal nature, the Drosophila brain is a valuable model system to study neuron development and circuit formation. To better understand the mechanisms underlying brain development, genetic manipulation tools can be utilized within lineages to visualize, knock down, or over-express proteins. Here, we will introduce the formation and development of lineages, discuss how one can utilize this model system, offer a comprehensive list of known lineages and their respective markers, and then briefly review studies that have utilized Drosophila neural lineages with a look at how this model system can benefit future endeavors.     

Detection and confirmation of Clostridium botulinum in water used for cooling at a plant producing low-acid canned foods

Our laboratory tested water samples used for cooling low-acid canned foods at a canning facility under investigation by the U.S. Food and Drug Administration. We used an enzyme-linked immunosorbent assay with digoxigenin-labeled antibodies (DIG-ELISA) and real-time PCR as screening methods and confirmed the presence of neurotoxin-producing Clostridium botulinum in the samples by mouse bioassay.