Unexpected inactivation of acceptor consensus splice sequence by a −3 C to T transition in intron 2 of the CFTR gene

Human Genetics - Cystic fibrosis is caused by mutations in the cystic fibrosis transmembrane conductance regulator gene (CFTR). Analysis of DNA from a pancreatic sufficient patient by means of...     

Formation and activity of covalent conjugates of poliovirus and ligands binding to cell surface structures

Disulfide-linked conjugates of poliovirus with streptavidin or concanavalin A were formed and the binding of the conjugates to mouse L cells that lack natural poliovirus receptors was studied. The conjugate with streptavidin was specifically bound to biotinylated L cells, but not to unmodified L cells. The conjugate with conA was bound to L cells in the absence of, but not in the presence of alpha-methyl mannoside. Incubation of L cells with bound conjugates did not produce virus, although the conjugates were highly infectious in HeLa cells, containing natural poliovirus receptors. This suggests that the artificially bound virus was unable to penetrate the L cells and start replication. The possibility that binding of the virus to the natural receptor is required for efficient infection is discussed.     

Use of RP4-prime plasmids constructed in vitro to promote a polarized transfer of the chromosome in Escherichia coli and Rhizobium meliloti.

Summary RP4-prime plasmids containing chromosomal fragments of either Escherichia coli or Rhizobium meliloti were constructed in vitro. When introduced into E. coli or R. meliloti respectively, they promoted a polarized transfer of the chromosome as demonstrated either by the gradient of transfer of various markers or by the study of the genetic constitution of recombinants. In E. coli, mobilization was shown to be dependent upon the presence of a functional rec A system. Inheritance of markers was due to their integration into the chromosome of the recipient as shown by the need for a functional rec A system in the recipient E. coli or by mobilization of recessive markers in R. meliloti. The system described could be applied to genetic mapping in any Gram negative bacteria.     

Screening for Vulnerability in Older Cancer Patients: The ONCODAGE Prospective Multicenter Cohort Study

Background

Geriatric Assessment is an appropriate method for identifying older cancer patients at risk of life-threatening events during therapy. Yet, it is underused in practice, mainly because it is time- and resource-consuming. This study aims to identify the best screening tool to identify older cancer patients requiring geriatric assessment by comparing the performance of two short assessment tools the G8 and the Vulnerable Elders Survey (VES-13).

Patients and Methods

The diagnostic accuracy of the G8 and the (VES-13) were evaluated in a prospective cohort study of 1674 cancer patients accrued before treatment in 23 health care facilities. 1435 were eligible and evaluable. Outcome measures were multidimensional geriatric assessment (MGA), sensitivity (primary), specificity, negative and positive predictive values and likelihood ratios of the G8 and VES-13, and predictive factors of 1-year survival rate.

Results

Patient median age was 78.2 years (70-98) with a majority of females (69.8%), various types of cancer including 53.9% breast, and 75.8% Performance Status 0-1. Impaired MGA, G8, and VES-13 were 80.2%, 68.4%, and 60.2%, respectively. Mean time to complete G8 or VES-13 was about five minutes. Reproducibility of the two questionnaires was good. G8 appeared more sensitive (76.5% versus 68.7%, P =  0.0046) whereas VES-13 was more specific (74.3% versus 64.4%, P<0.0001). Abnormal G8 score (HR = 2.72), advanced stage (HR = 3.30), male sex (HR = 2.69) and poor Performance Status (HR = 3.28) were independent prognostic factors of 1-year survival.

Conclusion

With good sensitivity and independent prognostic value on 1-year survival, the G8 questionnaire is currently one of the best screening tools available to identify older cancer patients requiring geriatric assessment, and we believe it should be implemented broadly in daily practice. Continuous research efforts should be pursued to refine the selection process of older cancer patients before potentially life-threatening therapy.     

A spiroplasma of serogroup IV causes a May-disease-like disorder of honeybees in Southwestern France

Honeybees affected by a disorder resembling the classical May disease in southwestern France contained numerous helical, motile organisms in their digestive tracts and hemolymph. Two strains of the organism (B31 and B39) were cultured and triply cloned in the BSR spiroplasma medium. The electrophoretic patterns of spiroplasmal proteins in 1 - and 2-dimensional polyacrylamide gels were similar to those of group IV spiroplasmas F1 and F2, cultured previously from flower surfaces in France. The organism could be introduced into adult bees by injection or food ingestion at various stages after emergence. Agent administered by either route multiplied to high titers in the hemolymph and killed the bees. Both multiplication and the induced lethal effect of the agent could be prevented by tetracycline but not penicillin. Spiroplasmas that were nearly identical to the B31 and B39 strains were also recovered from the surface of flowers collected within the area visited by the bees from the diseased hives.     

Chaotic and stochastic dynamics of epileptiform-like activities in sclerotic hippocampus resected from patients with pharmacoresistant epilepsy

The types of epileptiform activity occurring in the sclerotic hippocampus with highest incidence are interictal-like events (II) and periodic ictal spiking (PIS). These activities are classified according to their event rates, but it is still unclear if these rate differences are consequences of underlying physiological mechanisms. Identifying new and more specific information related to these two activities may bring insights to a better understanding about the epileptogenic process and new diagnosis. We applied Poincaré map analysis and Recurrence Quantification Analysis (RQA) onto 35 in vitro electrophysiological signals recorded from slices of 12 hippocampal tissues surgically resected from patients with pharmacoresistant temporal lobe epilepsy. These analyzes showed that the II activity is related to chaotic dynamics, whereas the PIS activity is related to deterministic periodic dynamics. Additionally, it indicates that their different rates are consequence of different endogenous dynamics. Finally, by using two computational models we were able to simulate the transition between II and PIS activities. The RQA was applied to different periods of these simulations to compare the recurrences between artificial and real signals, showing that different ranges of regularity-chaoticity can be directly associated with the generation of PIS and II activities.     

Stereotaxic Infusion of Oligomeric Amyloid-beta into the Mouse Hippocampus

Alzheimer’s disease is a neurodegenerative disease affecting the aging population. A key neuropathological feature of the disease is the over-production of amyloid-beta and the deposition of amyloid-beta plaques in brain regions of the afflicted individuals. Throughout the years scientists have generated numerous Alzheimer’s disease mouse models that attempt to replicate the amyloid-beta pathology. Unfortunately, the mouse models only selectively mimic the disease features. Neuronal death, a prominent effect in the brains of Alzheimer’s disease patients, is noticeably lacking in these mice. Hence, we and others have employed a method of directly infusing soluble oligomeric species of amyloid-beta - forms of amyloid-beta that have been proven to be most toxic to neurons - stereotaxically into the brain. In this report we utilize male C57BL/6J mice to document this surgical technique of increasing amyloid-beta levels in a select brain region. The infusion target is the dentate gyrus of the hippocampus because this brain structure, along with the basal forebrain that is connected by the cholinergic circuit, represents one of the areas of degeneration in the disease. The results of elevating amyloid-beta in the dentate gyrus via stereotaxic infusion reveal increases in neuron loss in the dentate gyrus within 1 week, while there is a concomitant increase in cell death and cholinergic neuron loss in the vertical limb of the diagonal band of Broca of the basal forebrain. These effects are observed up to 2 weeks. Our data suggests that the current amyloid-beta infusion model provides an alternative mouse model to address region specific neuron death in a short-term basis. The advantage of this model is that amyloid-beta can be elevated in a spatial and temporal manner.     

Comparative proteogenomics of twelve Roseobacter exoproteomes reveals different adaptive strategies among these marine bacteria

Roseobacters are generalist bacteria abundantly found in the oceans. Because little is known on how marine microorganisms interact in association or competition, we focused our attention on the microbial exoproteome, a key component in their interaction with extracellular milieu. Here we present a comparative analysis of the theoretically encoded exoproteome of twelve members of the Roseobacter group validated by extensive comparative proteogenomics. In silico analysis revealed that 30% of the encoded proteome of these microorganisms could be exported. The ratio of the different protein categories varied in accordance to the ecological distinctness of each strain, a trait reinforced by quantitative proteomics data. Despite the interspecies variations found, the most abundantly detected proteins by shotgun proteomics were from transporter, adhesion, motility, and toxin-like protein categories, defining four different plausible adaptive strategies within the Roseobacter group. In some strains the toxin-secretion strategy was over-represented with repeats-in-toxin-like proteins. Our results show that exoproteomes strongly depend on bacterial trophic strategy and can slightly change because of culture conditions. Simulated natural conditions and the effect of the indigenous microbial community on the exoproteome of Ruegeria pomeroyi DSS-3 were also assayed. Interestingly, we observed a significant depletion of the toxin-like proteins usually secreted by R. pomeroyi DSS-3 when grown in presence of a natural community sampled from a Mediterranean Sea port. The significance of this specific fraction of the exoproteome is discussed.