Assessing the influence of environmental gradients on seed mass variation in mountain grasslands using a spatial phylogenetic filtering approach

Several studies have demonstrated that seed mass is related to different environmental factors. However, they have taken no account of the joint effects of spatial and phylogenetic information. We analysed the distribution pattern of seed mass along an elevational gradient (1040–2380 m a.s.l.) at the community level in grasslands of the southern Alps. First, we tested the influence of environmental filters (climate and soil properties) in determining community-weighted seed mass variation in mountain grasslands. Second, we verified the relative roles of environmental filters in determining seed mass variation after accounting for spatial and phylogenetic autocorrelation with an eigenvector filtering approach. Temperature, soil fertility, and soil pH were the most important predictors for explaining seed mass variation; specifically, warmer, low fertility, and alkaline grasslands showed a greater seed mass. Inclusion of spatio-phylogenetic filters in the model increased its fit and the variance explained and reduced autocorrelation significantly but had substantial effects on the parameter estimates, with temperature and soil pH becoming insignificant. This effect may be ascribable to spatially structured phylogenetic patterns and could likely result from the common evolutionary histories shared by many species at sites with similar environmental conditions. Therefore, the observed patterns between community-weighted seed mass and both temperature and soil pH are not independent of phylogeny, but they are explained by the shared history within genera and families. Nevertheless, soil fertility remained the most important predictor for explaining seed mass variation. The results of this work contribute to better understanding the combined effects of environment and evolutionary factors for determining seed mass distributions in the spatial context of mountain grasslands. The observed relationships with climate and soil properties are particularly interesting because they are potentially relevant when modelling plant trait composition under changes in land use and climate.     

C-2 phenyl replacements to obtain potent quinoline-based Staphylococcus aureus NorA inhibitors

Abstract

NorA is the most studied efflux pump of Staphylococcus aureus and is responsible for high level resistance towards fluoroquinolone drugs. Although along the years many NorA efflux pump inhibitors (EPIs) have been reported, poor information is available about structure-activity relationship (SAR) around their nuclei and reliability of data supported by robust assays proving NorA inhibition. In this regard, we focussed efforts on the 2-phenylquinoline as a promising chemotype to develop potent NorA EPIs. Herein, we report SAR studies about the introduction of different aryl moieties on the quinoline C-2 position. The new derivative 37a showed an improved EPI activity (16-fold) with respect to the starting hit 1. Moreover, compound 37a exhibited a high potential in time-kill curves when combined with ciprofloxacin against SA-1199B (norA+). Also, 37a exhibited poor non-specific effect on bacterial membrane polarisation and showed an improvement in terms of “selectivity index” in comparison to 1.     

Mapping histological levels of 8-hydroxy-2′-deoxyguanosine in female reproductive organs

Oxidative stress is associated with many disease states including gynecologic disease. This process can damage lipids, proteins and DNA. The present study highlights the role of oxidative stress induced DNA damage as measured by 8-hydroxy-2-deoxyguanosine in development of benign gynecological conditions (BGC). Our aim was to map the oxidative DNA damage on female reproductive organs and highlight the high amount found in a variety of benign gynecologic disorders. Seventeen biopsy specimens from female pelvic organs were divided in two groups: healthy organs tissue and BGC tissue. Healthy organs biopsy tissue included the cervix, tubes, uterus, peritoneum, and topic endometrium in secretory phase. Benign gynecological biopsy tissue included hydrosalpinges, leiomyoma, adenomyosis and tubal cysts. Immunohistochemical staining showed significantly higher levels of DNA damage between BGC and healthy organs [19.36 % (6.20; 32.51) vs. 4.61 % (0.63; 8.53); P < 0.0344]. Our results highlight the involvement of oxidative stress DNA damage in female benign pelvic disease. Hydrosalpinges, leiomyoma, and adenomyosis exhibit the highest amounts of oxidative DNA damage in the pelvic cavity.     

Cryptic female choice favours sperm from major histocompatibility complex-dissimilar males

Cryptic female choice may enable polyandrous females to avoid inbreeding or bias offspring variability at key loci after mating. However, the role of these genetic benefits in cryptic female choice remains poorly understood. Female red junglefowl, Gallus gallus, bias sperm use in favour of unrelated males. Here, we experimentally investigate whether this bias is driven by relatedness per se, or by similarity at the major histocompatibility complex (MHC), genes central to vertebrate acquired immunity, where polymorphism is critical to an individual''s ability to combat pathogens. Through experimentally controlled natural matings, we confirm that selection against related males'' sperm occurs within the female reproductive tract but demonstrate that this is more accurately predicted by MHC similarity: controlling for relatedness per se, more sperm reached the eggs when partners were MHC-dissimilar. Importantly, this effect appeared largely owing to similarity at a single MHC locus (class I minor). Further, the effect of MHC similarity was lost following artificial insemination, suggesting that male phenotypic cues might be required for females to select sperm differentially. These results indicate that postmating mechanisms that reduce inbreeding may do so as a consequence of more specific strategies of cryptic female choice promoting MHC diversity in offspring.     

Risk of Severe Upper Gastrointestinal Complications among Oral Bisphosphonate Users

Background

Oral bisphosphonates (BPs) are the primary agents for the treatment of osteoporosis. Although BPs are generally well tolerated, serious gastrointestinal adverse events have been observed.

Aim

To assess the risk of severe upper gastrointestinal complications (UGIC) among BP users by means of a large study based on a network of Italian healthcare utilization databases.

Methods

A nested case-control study was carried out by including 110,220 patients aged 45 years or older who, from 2003 until 2005, were treated with oral BPs. Cases were the 862 patients who experienced the outcome (hospitalization for UGIC) until 2007. Up to 20 controls were randomly selected for each case. Conditional logistic regression model was used to estimate odds ratio (OR) associated with current use of BPs after adjusting for several covariates. A set of sensitivity analyses was performed in order to account for sources of systematic uncertainty.

Results

The adjusted OR for current use of BPs with respect to past use was 0.94 (95% CI 0.81 to 1.08). There was no evidence that this risk changed either with BP type and regimen, or concurrent use of other drugs or previous hospitalizations.

Conclusions

No evidence was found that current use of BPs increases the risk of severe upper gastrointestinal complications compared to past use.     

Evidence for the presence of photorespiration in desiccation-sensitive leaves of the C4 'resurrection' plant Sporobolus stapfianus during dehydration stress

The possible role of photorespiration as a general stress protectionmechanism, and in C₄ plant metabolism, is controversial. Inparticular, the potential involvement of photorespiration inthe acquisition of desiccation tolerance in ‘resurrection’plants is unknown. An investigation was carried out into whetherphotorespiration is present in leaves of the C₄ resurrectionplant Sporobolus stapfianus Gandoger (Poaceae) and whether itfunctions as a mechanism of stress resistance in the desiccation-tolerantyounger leaves (YL) of this plant. It is shown that the enzymesinvolved in the photorespiratory pathway maintain their activityuntil 88% relative water content (RWC) in both YL and desiccation-sensitiveolder leaves (OL). In subsequent stages of dehydration stress,the enzymatic activity declined similarly in both YL and OL.The content of the phorespiratory metabolite, serine, and ethanolamine,a direct product of serine decarboxylation, is higher in theearly stages of dehydration (88% RWC) in OL, suggesting a transientlyenhanced photorespiratory activity in these leaves. This wasconfirmed by simultaneous gas exchange and fluorescence measurements,showing suppression of the electron transport rate in OL exposedto non-photorespiratory conditions (2% O₂) at 85% RWC. It isconcluded that a higher photorespiratory electron transportoccurs in desiccation-sensitive OL, and it is therefore proposedthat the capacity to scavenge excess electrons through photorespirationdoes not contribute to protect leaves of the desiccation-tolerantYL of S. stapfianus during the stress. Key words: Ethanolamine, glycine, photorespiratory enzymes, photosynthesis, poikilohydric plant, serine Received 5 June 2007; Revised 3 September 2007 Accepted 17 September 2007     

Estimating the intrinsic rate of increase of Tetranychus urticae: which is the minimum number of immature individuals to consider?

The relationship between the number of immature individuals of Tetranychus urticae used to calculate life table parameters (sex ratio, development time, immature survival and the intrinsic rate of increase) and the accuracy of such determinations has been estimated. Additionally, the approach used in this paper, which considers each female offspring as a separate replicate, has allowed statistical comparison of the parameters obtained. At least the first four eggs from 16 females should be followed up to completion of their development to prevent the occurrence significant differences for the selected parameters. However, our results indicate that optimal sample sizes are different for the different life table parameters considered and should adapt to the preset level of accuracy.     

Finding of no tumor (pT0) in patients undergoing radical retropubic prostatectomy for clinically localized prostate cancer

OBJECTIVE: To evaluate features and clinical outcome of patients with clinically localized prostate cancer graded pT0 following radical retropubic prostatectomy (RRP). STUDY DESIGN: Between 1974 and 2001 we performed 1,135 RRPs for cT1-T2 prostate cancer, of which 386 (34%) underwent 3-6 months of neoadjuvant endocrine treatment (NHT) before RRP. Median clinical follow-up was 53.8 months (range 24-251). Estimation of likelihood events for biochemical relapse was calculated according to the Kaplan-Meier method. Statistical differences between curves were calculated using the log-rank test. RESULTS: In 24 cases (2.12%) routine histologic workup failed to detect residual tumor. The pT0 group contained a higher proportion of cTla-b patients and a biopsy Gleason score < or =6. A tendency toward lower pre-operatory PSA levels in the pT0 group compared to the pT2-3 group was shown. PSA progression was observed in 3 pT0 patients, all of whom previously underwent NHT. CONCLUSION: Patients pT0 at RRP presented with lower preoperative PSA values and low preoperative Gleason score compared to the pT+ group. Absence of tumor at pathology examination has a different clinical meaning when it occurs following NHT or in untreated patients. Patients pT0 after NHT may have a worse clinical outcome than pT0 untreated patients.