Inter‐kingdom signaling — symbiotic yeasts produce semiochemicals that attract their yellowjacket hosts

In recent studies, the yeast species Hanseniaspora uvarum and Lachancea thermotolerans were isolated from the digestive tract of four North American yellowjacket species (Hymenoptera: Vespidae), and attraction of yellowjackets to brewer's yeast, Saccharomyces cerevisiae (all Saccharomycetaceae), growing on fruit powder was demonstrated. We tested the hypothesis that Vespula spp. are attracted to cultures of H. uvarum and L. thermotolerans and their respective volatiles. In field experiments, we found that H. uvarum and L. thermotolerans are attractive to three species of yellowjacket, but only when grown on grape juice‐infused yeast peptone dextrose (YPD) agar. Using gas chromatography‐mass spectrometry, we analyzed the headspace volatiles produced by these yeasts, and field tested an 18‐component yeast synthetic semiochemical blend. This synthetic blend attracted western yellowjackets, Vespula pensylvanica (Saussure), but no other yellowjacket species. Acetic acid or ethanol added to the synthetic blend at biologically relevant doses either had no effect or significantly lowered trap captures. Our results demonstrate that yeast symbionts isolated from the digestive tract of yellowjackets are attractive to their hosts. Further research is needed to identify the volatiles mediating attraction of species other than V. pensylvanica to the yeast cultures.     

Simulation of stent deployment in a realistic human coronary artery

Background  

The process of restenosis after a stenting procedure is related to local biomechanical environment. Arterial wall stresses caused by the interaction of the stent with the vascular wall and possibly stress induced stent strut fracture are two important parameters. The knowledge of these parameters after stent deployment in a patient derived 3D reconstruction of a diseased coronary artery might give insights in the understanding of the process of restenosis.     

Quantitative variation in monoterpenes in four species of conifers

Eighteen monoterpenes found in bole and foliage volatiles of four sympatric species of conifers, Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, lodgepole pine, Pinus contorta var. latifolia Engelm., interior spruce, Picea engelmannii×glauca, and interior fir, Abies lasiocarpa×bifolia, in three locations in British Columbia, Canada, were analysed for quantitative variation (N=10 trees per sample) using standard and chiral gas chromatography. There was significant variation in monoterpene composition between bole and foliage in all four species. Principal components analysis revealed that the monoterpene profile of coastal Douglas-fir was significantly different from trees in the interior, supporting the hypothesis that coastal and interior populations represent distinct chemotypes. Although the four species did not differ qualitatively, there were significant differences in their quantitative monoterpene profiles in both bole and foliage. These differences were large enough to suggest that host selection by four species of coniferophagous bark beetles (Coleoptera: Scolytidae), specific to each of the above tree species, may depend in part on perception of, and behavioural response to quantitatively distinct blends of monoterpenes.     

Atmospheric microbiology in the northern Caribbean during African dust events

Between July 2000 and August 2001 forty-threeair samples were collected in the northernCaribbean: Twenty-six in the US VirginIslands, and 17 samples aboard ship during two1-week cruises. Samples were collected duringAfrican dust events and non-dust conditions andscreened for the presence of culturablebacteria and fungi. A total of 3,652 liters ofair were collected during non-dust conditions,with 19 bacteria and 28 fungi being recovered.During dust conditions a total of 2,369 litersof air were screened resulting in the recoveryof 171 bacteria and 76 fungi. A statisticallysignificant difference was found between thetwo data sets. These results support previousAfrican dust research and further demonstratethat dust particles can serve as a vessel forthe global dispersion of bacteria and fungi.Dustborne microorganisms may play a significantrole in the ecology and health of downwindecosystems.     

Microsatellite evolution in congeneric mammals: domestic and bighorn sheep

We compared genotypes at eight (AC)n microsatellite loci in domestic sheep (Ovis aries) and wild Rocky Mountain bighorn sheep (O. canadensis). The domestic sheep had greater genetic variation, higher allele-size variances, and larger allele sizes than the wild sheep. Accumulating evidence from higher taxonomic comparisons shows that these parameters are biased if microsatellite loci are selected in one taxon and used in another. Our results demonstrate similar biases between congeneric species. We compared standard measures of genetic variation, differentiation, and distance within and between species (H, D, FST) to newer measures based on allele-size variance (SW, SB, RST). The size-based distances better detected species-level divergence, but standard measures better distinguished allopatric populations. Empirical calibration of these measures at the subspecies level is needed to establish their useful ranges.      

Two RING Finger Proteins, the Oncoprotein PML and the Arenavirus Z Protein, Colocalize with the Nuclear Fraction of the Ribosomal P Proteins

The promyelocytic leukemia (PML) protein forms nuclear bodies which are relocated to the cytoplasm by the RNA virus lymphocytic choriomeningitis virus (LCMV). The viral Z protein directly binds to PML and can relocate the nuclear bodies. Others have observed that LCMV virions may contain ribosomes; hence, we investigated the effects of infection on the distribution of ribosomal P proteins (P0, P1, and P2) with PML as a reference point. We demonstrate an association of PML bodies with P proteins by indirect immunofluorescence and coimmunoprecipitation experiments, providing the first evidence of nucleic acid-binding proteins associated with PML bodies. We show that unlike PML, the P proteins are not redistributed upon infection. Immunofluorescence and coimmunoprecipitation studies indicate that the viral Z protein binds the nuclear, but not the cytoplasmic, fraction of P0. The nuclear fraction of P0 has been associated with translationally coupled DNA excision repair and with nonspecific endonuclease activity; thus, P0 may be involved in nucleic acid processing activities necessary for LCMV replication. During the infection process, PML, P1, and P2 are downregulated but P0 remains unchanged. Further, P0 is present in virions while PML is not, indicating some selectivity in the assembly of LCMV.     

EMG biofeedback for functional bladder-sphincter dyssynergia: A case study

The present study utilized EMG biofeedback in the treatment of functional bladder-sphincter dyssynergia, a learned incoordination of bladder and urethral sphincter activity during voiding. The condition is usually associated with a history of painful urination due to bladder infections, surgery, or harsh toilet training. The subject was an 8-year-old girl with chronic diurnal urinary frequency, urge incontinence, and nocturnal enuresis. Treatment consisted of intensive instruction in alternately tensing and relaxing her lower pelvic musculature, as well as relaxing during voiding. These exercises were accompanied by EMG biofeedback from perianal and perivaginal surface electrode sites. Home practice consisted of the tense-relax exercise, relaxation during voiding, and self-monitoring and record-keeping. There were 17 sessions over a period of 9 months. No medication was used. Marked reduction (to normal levels) in diurnal urgency and frequency occurred by the 3rd week of therapy, and complete recovery of normal function, including nocturnal continence without waking, occurred by the 13th therapy session, 5 months after therapy began. Follow-up 1 year after therapy revealed that these gains were being maintained. Pre- and posttherapy urodynamic studies corroborated the achievement of normal urinary function.     

Divergence in activation by poly I:C of human natural killer and killer cells

Summary Interferons consistently enhance spontaneous cellular cytotoxicity (SCC) mediated by natural killer (NK) cells. More controversial is the ability of interferons to enhance antibody-dependent cellular cytotoxicity (ADCC) mediated by killer (K) cells. Since NK and K cells appear to represent overlapping subpopulations of lymphocytes, the present study was undertaken to examine in greater detail the relationship between NK and K cell functional modulation by the potent interferon inducer, poly I:C. Utilizing peripheral mononuclear cells from a panel of 21 healthy individuals, treatment in vitro with poly I:C resulted in modulation of both SCC and ADCC. SCC was significantly enhanced in 52 of a series of 55 trials (95%), whereas ADCC was significantly enhanced in parallel in only 18 of the trials (33%). Cells which mediated enhanced ADCC were plastic-nonadherent, which is characteristic of K cells. SCC was consistently enhanced in all but two of the 14 individuals who were tested two or more times. By contrast, the ability of poly I:C to enhance ADCC varied between trials in 11 of these individuals. In the other three, ADCC enhancement never occurred. No correlation existed between SCC and ADCC augmentation despite use of the same target cell to assess the two lytic activities in parallel. Poly I:C exclusively enhanced SCC in 36 trials (65%) and exclusively enhanced ADCC in two trials (4%). Discordance between SCC and ADCC enhancement also occurred in three of eight trials (38%) in which lymphocytes were treated directly with interferon a. Results in long-term (18-h) ⁵¹Cr-release assays indicated that poly I:C accelerated the kinetics of ADCC without affecting the proportion of target cells lysed by K cells. By contrast, an increased proportion of target cells was killed by poly I:C-stimulated NK cells. These results suggest that the controversy concerning relative interferon effects upon NK and K cells derives from differences both quantitative and qualitative in nature. K cell activity is enhanced but at a relatively low frequency. Enhancement of NK cell activity is selective in the sense that it occurs independently of and with greater frequency than enhancement of K cell activity. Distinct biological mechanisms may, therefore, be involved in regulation and expression of NK and K cell activation by interferons.