The Diadenosine Homodinucleotide P18 Improves In Vitro Myelination in Experimental Charcot‐Marie‐Tooth Type 1A

Charcot‐Marie‐Tooth 1A (CMT1A) is a demyelinating hereditary neuropathy whose pathogenetic mechanisms are still poorly defined and an etiologic treatment is not yet available. An abnormally high intracellular Ca²⁺ concentration ([Ca²⁺]_i) occurs in Schwann cells from CMT1A rats (CMT1A SC) and is caused by overexpression of the purinoceptor P2X7. Normalization of the Ca²⁺ levels through down‐regulation of P2X7 appears to restore the normal phenotype of CMT1A SC in vitro. We recently demonstrated that the diadenosine 5′,5′′′‐P1, P2‐diphosphate (Ap2A) isomer P18 behaves as an antagonist of the P2X7 purinergic receptor, effectively blocking channel opening induced by ATP. In addition, P18 behaves as a P2Y11 agonist, inducing cAMP overproduction in P2Y11‐overexpressing cells. Here we investigated the in vitro effects of P18 on CMT1A SC. We observed that basal levels of intracellular cAMP ([cAMP]_i), a known regulator of SC differentiation and myelination, are significantly lower in CMT1A SC than in wild‐type (wt) cells. P18 increased [cAMP]_i in both CMT1A and wt SC, and this effects was blunted by NF157, a specific P2Y11 antagonist. Prolonged treatment of organotypic dorsal root ganglia (DRG) cultures with P18 significantly increased expression of myelin protein zero, a marker of myelin production, in both CMT1A and wt cultures. Interestingly, P18 decreased the content of non‐phosphorylated neurofilaments, a marker of axonal damage, only in CMT1A DRG cultures. These results suggest that P2X7 antagonists, in combination with [cAMP]_i‐increasing agents, could represent a therapeutic strategy aimed at correcting the molecular derangements causing the CMT1A phenotype. J. Cell. Biochem. 115: 161–167, 2014. © 2013 Wiley Periodicals, Inc.     

Evaluation of Porcine Intestinal Epitheliocytes as an In vitro Immunoassay System for the Selection of Probiotic Bifidobacteria to Alleviate Inflammatory Bowel Disease

Probiotics and Antimicrobial Proteins - The use of in vitro systems that allow efficient selection of probiotic candidates with immunomodulatory properties could significantly minimize the use of...     

Distinct Lipid Rafts in Subdomains from Human Placental Apical Syncytiotrophoblast Membranes

We report on the characteristics of raft domains in the apical membrane from human placental syncytiotrophoblast (hSTB), an epithelium responsible for maternal-fetal exchange. Previously, we described two isolated fractions of the hSTB apical membrane: a classical microvillous membrane (MVM) and a light microvillous membrane (LMVM). Detergent-resistant microdomains (DRMs) from MVM and LMVM were prepared with Triton X-100 followed by flotation in a sucrose gradient and tested by Western and dot blot with raft markers (placental alkaline phosphatase, lipid ganglioside, annexin 2) and transferrin receptor as a nonraft marker. DRMs from both fractions showed a consistent peak for these markers, except that the DRMs from MVM had no annexin 2 mark. Cholesterol depletion modified the segregation in both groups of DRMs. Our results show two distinguishable lipid raft subsets from MVM and LMVM. Additionally, we found significant differences between MVM and LMVM in cholesterol content and in expression of cytoskeletal proteins. MVM is enriched in ezrin and beta-actin; in contrast, cholesterol and cytokeratin-7 are more abundant in LMVM. These differences may explain the distinct properties of the lipid raft subtypes.     

Pyrrolomycins as potential anti-staphylococcal biofilms agents

With the goal of discovering new anti-infective agents active against microbial biofilms, this investigation focused on some natural pyrrolomycins, a family of halogenated pyrrole antibiotics. In this study the anti-staphylococcal biofilm activity of pyrrolomycins C, D, F1, F2a, F2b, F3 and of the synthesized related compounds I, II, III were investigated. The susceptibility of six staphylococcal biofilms was determined by methyltiazotetrazolium staining. Most of the compounds were active at concentrations of 1.5 μg ml^?1 with significant inhibition percentages. A few of the compounds were active at the lowest screening concentration of 0.045 μg ml^?1. The population log reduction of activity against the two best biofilm forming Staphylococcus aureus strains as determined by viable plate counts is also reported. In order to adequately assess the utility of these compounds, their toxicity against human cells was evaluated. It is concluded that pyrrolomycins and synthetic derivatives are promising compounds for developing novel effective chemical countermeasures against staphylococcal biofilms.     

Variation in parental rearing expenditure triggers short‐term physiological effects on offspring in a long‐lived seabird

Parental care in long‐lived bird species involves a trade‐off between the benefits of increasing the effort expended on current offspring and the costs that this represents for future reproductive output. Under regimes of high environmental variability, long‐lived seabirds can adjust their breeding effort to buffer the negative effects of this variability on their offspring. However, the potential impacts of variation in breeding effort on offspring physiology in the short term and on longer‐term survival are poorly understood. In this study, we manipulated brood age through a cross‐fostering experiment to assess whether increasing or decreasing parental reproductive expenditure led to costs in Blue‐footed Booby Sula nebouxii chicks. Specifically, we tested the consequences of altered parental reproductive expenditure on the offspring's physiological condition (plasma metabolites, heterophil to lymphocyte ratio (H/L) and body condition index (BCI)) and survival. Offspring from broods in which parental investment was experimentally increased showed a lower BCI and lower alkaline phosphatase levels and higher H/L ratios than controls. Conversely, offspring showed the opposite pattern when reproductive expenditure was experimentally decreased. We observed no effects of manipulation of parental investment on triglyceride levels or on survival rates. Although our findings suggest that Blue‐footed Booby parents have the ability to adjust their breeding effort according to the demands of their offspring, parental effort could influence the effect of hatching order by suppressing the aggressive tendency of the senior chick.     

Complete reversion of the abo phenotype in D. melanogaster occurs only when the blood transposon is lost from region 32E.

Summary The abnormal oocyte phenotype is characterized by instability, as shown by the loss and reappearance of the abo maternal effect under specific genetic conditions. Our previous finding that a correlation exists between the abo phenotype and the presence of a blood transposon in region 32E, led us to perform an extensive genetic and molecular analysis of the most significant aspects of the abo phenotype in different genetic backgrounds. The results of these experiments can be summarized as follows: Complete reversion occurs only when the blood transposon is lost, thus definitively demonstrating that the insertion of the blood transposon in region 32E is the molecular event that causes the pleiotropic abo phenotype. Partial reversion can also occur without loss of the transposon, indicating that different molecular pathways may be involved in the loss of the abo phenotype. Reappearance of the full abo phenotype can occur only in heterozygous lines constructed from partially revertant abo homozygous lines that have not lost the blood transposon.     

Thermal ecology of two sympatric saxicolous lizards of the genus Phymaturus from the Payunia region (Argentina)

We evaluated the thermal biology of two sympatric saxicolous species of the genus Phymaturus, endemic from the Argentine Payunia region. Taking into account that the distributional range of Phymaturus roigorum (the largest species) is greater than the range of P. payuniae, we evaluated the habitat (type of rocks) used by these species. We recorded body temperature and operative temperatures in different habitats, and we determined the preferred body temperature in the laboratory. We compared the thermal quality of habitats occupied and not occupied by Phymaturus payuniae, and the accuracy and effectiveness of thermoregulation between species.     

Streptococcus pneumoniae Coinfection Is Correlated with the Severity of H1N1 Pandemic Influenza

Background

Initial reports in May 2009 of the novel influenza strain H1N1pdm estimated a case fatality rate (CFR) of 0.6%, similar to that of seasonal influenza. In July 2009, however, Argentina reported 3056 cases with 137 deaths, representing a CFR of 4.5%. Potential explanations for increased CFR included virus reassortment or genetic drift, or infection of a more vulnerable population. Virus genomic sequencing of 26 Argentinian samples representing both severe and mild disease indicated no evidence of reassortment, mutations associated with resistance to antiviral drugs, or genetic drift that might contribute to virulence. Furthermore, no evidence was found for increased frequency of risk factors for H1N1pdm disease.

Methods/Principal Findings

We examined nasopharyngeal swab samples (NPS) from 199 cases of H1N1pdm infection from Argentina with MassTag PCR, testing for 33 additional microbial agents. The study population consisted of 199 H1N1pdm-infected subjects sampled between 23 June and 4 July 2009. Thirty-nine had severe disease defined as death (n = 20) or hospitalization (n = 19); 160 had mild disease. At least one additional agent of potential pathogenic importance was identified in 152 samples (76%), including Streptococcus pneumoniae (n = 62); Haemophilus influenzae (n = 104); human respiratory syncytial virus A (n = 11) and B (n = 1); human rhinovirus A (n = 1) and B (n = 4); human coronaviruses 229E (n = 1) and OC43 (n = 2); Klebsiella pneumoniae (n = 2); Acinetobacter baumannii (n = 2); Serratia marcescens (n = 1); and Staphylococcus aureus (n = 35) and methicillin-resistant S. aureus (MRSA, n = 6). The presence of S. pneumoniae was strongly correlated with severe disease. S. pneumoniae was present in 56.4% of severe cases versus 25% of mild cases; more than one-third of H1N1pdm NPS with S. pneumoniae were from subjects with severe disease (22 of 62 S. pneumoniae-positive NPS, p = 0.0004). In subjects 6 to 55 years of age, the adjusted odds ratio (OR) of severe disease in the presence of S. pneumoniae was 125.5 (95% confidence interval [CI], 16.95, 928.72; p<0.0001).

Conclusions/Significance

The association of S. pneumoniae with morbidity and mortality is established in the current and previous influenza pandemics. However, this study is the first to demonstrate the prognostic significance of non-invasive antemortem diagnosis of S. pneumoniae infection and may provide insights into clinical management.     

DR antigen expression on ovarian carcinoma cells does not correlate with their capacity to elicit an autologous proliferative response

Summary Expression of HLA-DR antigens by purified preparations of human ovarian carcinoma cells freshly isolated from surgical specimens was examined in parallel with the capacity of tumor cells to elicit a blastogenic response from autologous lymphocytes in mixed lymphocyte-tumor culture (MLTC) assay. Of 21 tumor preparations, 11 (52%) reacted with monoclonal antibodies 279 and/or 949 specific for a monomorphic determinant of HLA-DR antigens, with heterogeneous positivity, ranging between 30% and 95%. In this series of patients positive MLTC occurred in 8/21 individual experiments. The HLA-DR expression was proportionally similar in tumors giving positive MLTC (4/8=50%) and negative MLTC (7/13=53%). The lack of correlation between DR expression on tumor cells and stimulatory activity in autologous MLTC and the fact that DR-negative tumors could induce lymphocyte stimulation, support the hypothesis that blastogenesis occurs upon recognition of tumor-associated antigens, different from DR molecules, possibly tumor-specific antigens.