species are bacterial symbionts of
nematodes and pathogens of susceptible insects. Different species of
nematodes carrying specific species of
can invade the same insect, thereby setting up ...competition for nutrients within the insect environment. While
species produce both diverse antibiotic compounds and prophage-derived R-type bacteriocins (xenorhabdicins), the functions of these molecules during competition in a host are not well understood.
(
), the symbiont of
possesses a remnant P2-like phage tail cluster,
1, that encodes genes for xenorhabdicin production. We show that inactivation of either tail sheath (
) or tail fibre (
) genes eliminated xenorhabdicin production. Preparations of
xenorhabdicin displayed a narrow spectrum of activity towards other
and
species. One species,
(
), was highly sensitive to
xenorhabdicin but did not produce xenorhabdicin that was active against
. Instead,
produced high-level antibiotic activity against
when grown in complex medium and lower levels when grown in defined medium (Grace's medium). Conversely,
did not produce detectable levels of antibiotic activity against
. To study the relative contributions of
xenorhabdicin and
antibiotics in interspecies competition in which the respective
species produce antagonistic activities against each other, we co-inoculated cultures with both
species. In both types of media
outcompeted
, suggesting that antibiotics produced by
determined the outcome of the competition. In contrast,
outcompeted
in competitions performed by co-injection in the insect
, while in competition with the xenorhabdicin-deficient strain (
),
was dominant. Thus, xenorhabdicin was required for
to outcompete
in a natural host environment. These results highlight the importance of studying the role of antagonistic compounds under natural biological conditions.
Introduction
In heart transplant recipients, nonadherence is associated with higher risk of morbidity and mortality.
Research Question
Can a psychoeducational intervention enhance adherence to ...medical recommendations?
Design
We randomized 200 patients awaiting heart transplantation on the high urgency wait list to a manualized psychoeducational intervention or standard care. Follow-up continued to three years after transplantation. Primary endpoint was adherence to immunosuppressive medication, assessed at 3, 6, 12, 24, and 36 months posttransplant. Secondary endpoints were barriers to adherence during follow-up and clinical outcomes, including cardiac rejection within the first postoperative year and postoperative 3-year mortality.
Results
Fifty patients died before or within the first 3 months of transplantation. The primary endpoint was analyzed in 66 patients in the intervention group and 66 in the control group. Both study groups showed almost maximal adherence to immunosuppressive medication throughout follow-up, with no significant time x treatment interaction (P>0.99). Likewise, there was no significant time x treatment interaction (P=0.41) on barriers to adherence. The percentage of patients with International Society for Heart and Lung Transplantation standard grade 1 and 2 rejection was in the intervention and control groups 82.5% and 78.7%, respectively, and 8.8% and 13.1%, respectively, without significant differences between study groups (P=0.75). Considering all randomized and transplanted patients in the intervention group (N=85) and control group (N=87), postoperative 3-year mortality was 29.4% and 27.6%, respectively (P=0.82).
Conclusions
Adherence to immunosuppressive medication was high, even without a complex, manualized psychoeducational intervention. The intervention had no significant positive impact on cardiac rejection and mortality.
Beauveria bassiana is a facultative entomopathogen with an extremely broad host range that is used as a commercial biopesticide for the control of insects of agricultural, veterinary and medical ...significance.
B. bassiana produces bassianolide, a cyclooligomer depsipeptide secondary metabolite. We have cloned the
bbBsls gene of
B. bassiana encoding a nonribosomal peptide synthetase (NRPS). Targeted inactivation of the
B. bassiana genomic copy of
bbBsls abolished bassianolide production, but did not affect the biosynthesis of beauvericin, another cyclodepsipeptide produced by the strain. Comparative sequence analysis of the BbBSLS bassianolide synthetase revealed enzymatic domains for the iterative synthesis of an enzyme-bound dipeptidol monomer intermediate from
d-2-hydroxyisovalerate and
l-leucine. Further BbBSLS domains are predicted to catalyze the formation of the cyclic tetrameric ester bassianolide by recursive condensations of this monomer. Comparative infection assays against three selected insect hosts established bassianolide as a highly significant virulence factor of
B. bassiana.
Display omitted
A large fraction of the volume of Beluga whale (Delphinapterus leucas) teeth consists of cementum, a mineralized tissue which grows throughout the life of the animal and to which the ...periodontal ligaments attach. Annular growth bands or growth layer groups (GLGs) form within Beluga cementum, and this study investigates GLG structure using X-ray fluorescence mapping and X-ray diffraction mapping with microbeams of synchrotron radiation. The Ca and Zn fluorescent intensities and carbonated hydroxyapatite (cAp) diffracted intensities rise and fall together and match the light-dark bands visible in transmitted light micrographs. Within the bands of maximum Ca and Zn intensity, the ratio of Zn to Ca is slightly higher than in the minima bands. Further, the GLG cAp, Ca and Zn modulation is preserved throughout the cementum for durations >25year.
Cementum is an important tooth tissue to which the periodontal ligaments attach and consists primarily of carbonated apatite mineral and collagen. In optical microscopy of cementum thin sections, light/dark bands are formed annually, and age at death is determined by counting these bands. We employ synchrotron X-ray diffraction and X-ray fluorescence mapping to show the bands in Beluga whale cementum result from differences in mineral content and not from differences in collagen orientation as was concluded by others. Variation in Zn fluorescent intensity was found to be very sensitive indicator of changing biomineralization and suggest that Zn plays an important role this process.
The vertebral centra of sharks consist of cartilage, and many species’ centra contain a bioapatite related to that in bone. Centra microarchitectures at the 0.5-50 µm scale do not appear to have been ...described previously. This study examines centrum microarchitecture in lamniform and carcharhiniform sharks with synchrotron microComputed Tomography (microCT), scanning electron microscopy and spectroscopy and light microscopy. The analysis centers on the blue shark (carcharhiniform) and shortfin mako (lamniform), species studied with all three modalities. Synchrotron microCT results from seven other species complete the report. The main centrum structures, the corpus calcareum and intermedialia, consist of fine, closely-spaced, mineralized trabeculae whose mean thicknesses <Tb.Th> and spacings <Tb.Sp> range from 4.5 to 11.2 µm and 4.5 to 15.6 µm, respectively. A significant (p = 0.00001) positive linear relationship between <Tb.Th> and <Tb.Sp> exists for multiple positions within one mako centrum. Carcharhiniform species’ <Tb.Th> and <Tb.Sp> exhibit an inverse linear relationship (p = 0.005) while in lamniforms these variables tend toward a positive relationship which does not reach statistical significance (p = 0.099). In all species, the trabeculae form an uninterrupted, interconnected network, and the unmineralized volumes are similarly interconnected. Small differences in mineralization level are observed in trabeculae. Centrum growth band pairs are found to consist of locally higher /lower mineral volume fraction. Within the intermedialia, radial canals and radial microrods were characterized, and compacted trabeculae are prominent in the mako intermedialia. The centra's mineralized central zones were non-trabecular and are also described.
This study's novel result is the demonstration that the mineralized cartilage of sharks’ vertebral bodies (centra) consists of a fine 3D array of interconnected plates (trabeculae) and an interpenetrating network of unmineralized tissue. This microstructure is radically different from that in tesserae or in teeth, the other main mineralized shark tissues. Using volumetric synchrotron microComputed Tomography, numerical values of mean trabecular thickness and spacing and their relationship were measured for nine species. Scanning electron microscopy added a higher resolution view of the microstructures, and histology provided complementary information on cartilage and cells. The present results suggest centra microstructure helps accommodate the very large in vivo strains and may prevent damage accumulation during millions of cycles of swimming-induced loading.
Display omitted
Xenorhabdus bovienii bacteria have a dual lifestyle: they are mutualistic symbionts to many species of Steinernema nematodes and are pathogens to a wide array of insects. Previous studies have shown ...that virulence of X.bovienii-Steinernema spp. pairs decreases when the nematodes associate with non-cognate bacterial strains. However, the virulence of the X. bovienii strains alone has not been fully investigated. In this study, we characterized the virulence of nine X. bovienii strains in Galleria mellonella and Spodoptera littoralis and performed a comparative genomic analysis to correlate observed phenotypes with strain genotypes. Two X. bovienii strains were found to be highly virulent against the tested insect hosts, while three strains displayed attenuated insect virulence. Comparative genomic analyses revealed the presence of several clusters present only in virulent strains, including a predicted type VI secretion system (T6SS). We performed intra-species-competition assays, and showed that the virulent T6SS+ strains generally outcompeted the less virulent T6SS- strains. Thus, we speculate that the T6SS in X. bovienii may be another addition to the arsenal of antibacterial mechanisms expressed by these bacteria in an insect, where it could potentially play three key roles: (1) competition against the insect host microbiota; (2) protection of the insect cadaver from necrotrophic microbial competitors; and (3) outcompeting other Xenorhabdus species and/or strains when co-infections occur.
Breast cancer (BC) is one of the most common cancers in the United States. Advances in detection and treatment have resulted in an increased survival rate, meaning an increasing population ...experiencing declines in muscle mass and strength. Creatine supplementation has consistently demonstrated improvements in strength and muscle performance in older adults, though these findings have not been extended to cancer populations.
The purpose of this study was to investigate the effects of short-term creatine supplementation on muscular performance in BC survivors.
Using a double-blind, placebo-controlled, randomized design, 19 female BC survivors (mean ± SD age = 57.63 ± 10.77 years) were assigned to creatine (SUPP) (
= 9) or dextrose placebo (PLA) (
= 10) groups. The participants completed two familiarization sessions, then two test sessions, each separated by 7 days, where the participants supplemented with 5 g of SUPP or PLA 4 times/day between sessions. The testing sessions included sit-to-stand power, isometric/isokinetic peak torque, and upper/lower body strength via 10 repetition maximum (10RM) tests. The interaction between supplement (SUPP vs. PLA) and time (Pre vs. Post) was examined using a group × time ANOVA and effect sizes.
No significant effects were observed for sit-to-stand power (
= 0.471; η
= 0.031), peak torque at 60°/second (
= 0.533; η
= 0.023), peak torque at 120°/second (
= 0.944; η
< 0.001), isometric peak torque (
= 0.905; η
< 0.001), 10RM chest press (
= 0.407; η
= 0.041), and 10RM leg extension (
= 0.932; η
< 0.001). However, a large effect size for time occurred for the 10RM chest press (η
= 0.531) and leg extension (η
= 0.422).
Seven days of creatine supplementation does not influence muscular performance among BC survivors.
Skeletal muscle hypertrophy is typically considered to be a slow process. However, this is partly because the time course for hypertrophy has not been thoroughly examined. The purpose of this study ...was to use weekly testing to determine a precise time course of skeletal muscle hypertrophy during a resistance training program. Twenty-five healthy, sedentary men performed 8 weeks of high-intensity resistance training. Whole muscle cross-sectional area (CSA) of the dominant thigh was assessed using a peripheral quantitative computed tomography scanner during each week of training (W1–W8). Isometric maximum voluntary contractions (MVC) were also measured each week. After only two training sessions (W1), the mean thigh muscle CSA increased by 5.0 cm
2
(3.46%;
p
< 0.05) from the pre-testing (P1) and continued to increase with each testing session. It is possible that muscular edema may have influenced the early CSA results. To adjust for this possibility, with edema assumedly at its highest at W1, the next significant increase from W1 was at W3. W4 was the first significant increase of MVC over P1. Therefore, significant skeletal muscle hypertrophy likely occurred around weeks 3–4. Overall, from the pre-testing to W8, there was an increase of 13.9 cm
2
(9.60%). These findings suggested that training-induced skeletal muscle hypertrophy may occur early in a training program.
Dynamical histories of planetary systems, as well as the atmospheric evolution of highly irradiated planets, can be studied by characterizing the ultra-short-period planet population, which the TESS ...mission is particularly well suited to discover. Here, we report on the follow-up of a transit signal detected in the TESS sector 19 photometric time series of the M3.0 V star TOI-1685 (2MASS J04342248+4302148). We confirm the planetary nature of the transit signal, which has a period of
P
b
= 0.6691403
−0.0000021
+0.0000023
d, using precise radial velocity measurements taken with the CARMENES spectrograph. From the joint photometry and radial velocity analysis, we estimate the following parameters for TOI-1685 b: a mass of
M
b
= 3.78
−0.63
+0.63
M
⊕
, a radius of
R
b
= 1.70
−0.07
+0.07
R
⊕
, which together result in a bulk density of
ρ
b
= 4.21
−0.82
+0.95
g cm
−3
, and an equilibrium temperature of
T
eq
= 1069
−16
+16
K. TOI-1685 b is the least dense ultra-short-period planet around an M dwarf known to date. TOI-1685 b is also one of the hottest transiting super-Earth planets with accurate dynamical mass measurements, which makes it a particularly attractive target for thermal emission spectroscopy. Additionally, we report with moderate evidence an additional non-transiting planet candidate in the system, TOI-1685 c, which has an orbital period of
P
c
= 9.02
−0.12
+0.10
d.
Introduction: The purpose of this study was to examine the influence of fatigue on the average firing rate versus recruitment threshold relationships for the vastus lateralis (VL) and vastus ...medialis. Methods: Nineteen subjects performed ten maximum voluntary contractions of the dominant leg extensors. Before and after this fatiguing protocol, the subjects performed a trapezoid isometric muscle action of the leg extensors, and bipolar surface electromyographic signals were detected from both muscles. These signals were then decomposed into individual motor unit action potential trains. For each subject and muscle, the relationship between average firing rate and recruitment threshold was examined using linear regression analyses. Results: For the VL, the linear slope coefficients and y‐intercepts for these relationships increased and decreased, respectively, after fatigue. For both muscles, many of the motor units decreased their firing rates. Conclusion: With fatigue, recruitment of higher threshold motor units resulted in an increase in slope for the VL. Muscle Nerve 45: 100–109, 2012
PDF
