Identification of the lactococcal exonuclease/recombinase and its modulation by the putative Chi sequence

Studies of RecBCD–Chi interactions in Escherichia coli have served as a model to understand recombination events in bacteria. However, the existence of similar interactions has not been demonstrated in bacteria unrelated to E. coli. We developed an in vivo model to examine components of dsDNA break repair in various microorganisms. Here, we identify the major exonuclease in Lactococcus lactis, a Gram-positive organism evolutionarily distant from E. coli, and provide evidence for exonuclease–Chi interactions. Insertional mutants of L. lactis, screened as exonuclease-deficient, affected a single locus and resulted in UV sensitivity and recombination deficiency. The cloned lactococcal genes (called rexAB) restored UV resistance, recombination proficiency, and the capacity to degrade linear DNA, to an E. coli recBCD mutant. In this context, DNA degradation is specifically blocked by the putative lactococcal Chi site (5′-GCGCGTG-3′), but not by the E. coli Chi (5′-GCTGGTGG-3′) site. RexAB-mediated recombination was shown to be stimulated ≈27-fold by lactococcal Chi. Our results reveal that RexAB fulfills the biological roles of RecBCD and indicate that its activity is modulated by a short DNA sequence. We speculate that exonuclease/recombinase enzymes whose activities are modulated by short DNA sequences are widespread among bacteria

Successful transureteropyelostomy after heminephrectomy of a bilateral hydronephrotic horseshoe kidney: a case report

<p>Abstract</p> <p>Introduction</p> <p>Horseshoe kidney is a rare congenital malformation that is found in approximately 0.25% of the general population and usually remains asymptomatic.</p> <p>Case presentation</p> <p>We report a successful transureteropyelostomy after heminephrectomy of the non-functional right moiety in a 25-year-old man with horseshoe kidney who had a combined 50% functional loss and hydronephrosis due to multiple distal ureteral strictures on the functionally remaining left side. Continuous ureteral stenting of the remaining part of the former horseshoe kidney was avoided during a follow-up of 2 years.</p> <p>Conclusion</p> <p>Urologists are often faced with technically difficult cases that are not responsive to standard operative procedures, and this case illustrates an individual surgical approach in a clinical situation.</p

Synaptic Accumulation of PSD-95 and Synaptic Function Regulated by Phosphorylation of Serine-295 of PSD-95

SummaryThe scaffold protein PSD-95 promotes the maturation and strengthening of excitatory synapses, functions that require proper localization of PSD-95 in the postsynaptic density (PSD). Here we report that phosphorylation of ser-295 enhances the synaptic accumulation of PSD-95 and the ability of PSD-95 to recruit surface AMPA receptors and potentiate excitatory postsynaptic currents. We present evidence that a Rac1-JNK1 signaling pathway mediates ser-295 phosphorylation and regulates synaptic content of PSD-95. Ser-295 phosphorylation is suppressed by chronic elevation, and increased by chronic silencing, of synaptic activity. Rapid dephosphorylation of ser-295 occurs in response to NMDA treatment that causes chemical long-term depression (LTD). Overexpression of a phosphomimicking mutant (S295D) of PSD-95 inhibited NMDA-induced AMPA receptor internalization and blocked the induction of LTD. The data suggest that synaptic strength can be regulated by phosphorylation-dephosphorylation of ser-295 of PSD-95 and that synaptic depression requires the dephosphorylation of ser-295

Thermochemistry of Alane Complexes for Hydrogen Storage: A Theoretical and Experimental Comparison

Knowledge of the relative stabilities of alane (AlH3) complexes with electron donors is essential for identifying hydrogen storage materials for vehicular applications that can be regenerated by off-board methods; however, almost no thermodynamic data are available to make this assessment. To fill this gap, we employed the G4(MP2) method to determine heats of formation, entropies, and Gibbs free energies of formation for thirty-eight alane complexes with NH3-nRn (R = Me, Et; n = 0-3), pyridine, pyrazine, triethylenediamine (TEDA), quinuclidine, OH2-nRn (R = Me, Et; n = 0-2), dioxane, and tetrahydrofuran (THF). Monomer, bis, and selected dimer complex geometries were considered. Using these data, we computed the thermodynamics of the key formation and dehydrogenation reactions that would occur during hydrogen delivery and alane regeneration, from which trends in complex stability were identified. These predictions were tested by synthesizing six amine-alane complexes involving trimethylamine, triethylamine, dimethylethylamine, TEDA, quinuclidine, and hexamine, and obtaining upper limits of delta G for their formation from metallic aluminum. Combining these computational and experimental results, we establish a criterion for complex stability relevant to hydrogen storage that can be used to assess potential ligands prior to attempting synthesis of the alane complex. Based on this, we conclude that only a subset of the tertiary amine complexes considered and none of the ether complexes can be successfully formed by direct reaction with aluminum and regenerated in an alane-based hydrogen storage system.Comment: Accepted by the Journal of Physical Chemistry

Cyclopiazonic Acid Biosynthesis of Aspergillus flavus and Aspergillus oryzae

Cyclopiazonic acid (CPA) is an indole-tetramic acid neurotoxin produced by some of the same strains of A. flavus that produce aflatoxins and by some Aspergillus oryzae strains. Despite its discovery 40 years ago, few reviews of its toxicity and biosynthesis have been reported. This review examines what is currently known about the toxicity of CPA to animals and humans, both by itself or in combination with other mycotoxins. The review also discusses CPA biosynthesis and the genetic diversity of CPA production in A. flavus/oryzae populations

Whole Blood DNA Aberrant Methylation in Pancreatic Adenocarcinoma Shows Association with the Course of the Disease: A Pilot Study

Pancreatic tumors are usually diagnosed at an advanced stage in the progression of the disease, thus reducing the survival chances of the patients. Non-invasive early detection would greatly enhance therapy and survival rates. Toward this aim, we investigated in a pilot study the power of methylation changes in whole blood as predictive markers for the detection of pancreatic tumors. We investigated methylation levels at selected CpG sites in the CpG rich regions at the promoter regions of p16, RARbeta, TNFRSF10C, APC, ACIN1, DAPK1, 3OST2, BCL2 and CD44 in the blood of 30 pancreatic tumor patients and in the blood of 49 matching controls. In addition, we studied LINE-1 and Alu repeats using degenerate amplification approach as a surrogate marker for genome-wide methylation. The site-specific methylation measurements at selected CpG sites were done by the SIRPH method. Our results show that in the patient’s blood, tumor suppressor genes were slightly but significantly higher methylated at several CpG sites, while repeats were slightly less methylated compared to control blood. This was found to be significantly associated with higher risk for pancreatic ductal adenocarcinoma. Additionally, high methylation levels at TNFRSCF10C were associated with positive perineural spread of tumor cells, while higher methylation levels of TNFRSF10C and ACIN1 were significantly associated with shorter survival. This pilot study shows that methylation changes in blood could provide a promising method for early detection of pancreatic tumors. However, larger studies must be carried out to explore the clinical usefulness of a whole blood methylation based test for non-invasive early detection of pancreatic tumors

Catharanthus roseus flower extract has wound-healing activity in Sprague Dawley rats

BACKGROUND: Catharanthus roseus L (C. roseus) has been used to treat a wide assortment of diseases including diabetes. The objective of our study was to evaluate the antimicrobial and wound healing activity of the flower extract of Catharanthus in rats. METHODS: Wound healing activity was determined in rats, after administration (100 mg kg(-1 )day(-1)) of the ethanol extract of C. roseus flower, using excision, incision and dead space wounds models. The animals were divided into two groups of 6 each in all the models. In the excision model, group 1 animals were topically treated with carboxymethyl cellulose as placebo control and group 2 received topical application of the ethanol extract of C. roseus at a dose of 100 mg/kg body weight/day. In an incision and dead space model group 1 animals were given normal saline and group 2 received the extract orally at a dose of 100 mg kg(-1 )day(-1). Healing was assessed by the rate of wound contraction, period of epithelization, tensile strength (skin breaking strength), granulation tissue weight, and hydoxyproline content. Antimicrobial activity of the flower extract against four microorganisms was also assessed RESULTS: The extract of C. roseus significantly increased the wound breaking strength in the incision wound model compared with controls (P < 0.001). The extract-treated wounds were found to epithelialize faster, and the rate of wound contraction was significantly increased in comparison to control wounds (P < 0.001), Wet and dry granulation tissue weights, and hydroxyproline content in a dead space wound model increased significantly (p < 0.05). Pseudomonas aeruginosa and Staphylococcus aureus demonstrated sensitivity to C. roseus CONCLUSION: Increased wound contraction and tensile strength, augmented hydroxyproline content along with antimicrobial activity support the use of C. roseus in the topical management of wound healing

A Cell Culture–Derived Influenza Vaccine Provides Consistent Protection Against Infection and Reduces the Duration and Severity of Disease in Infected Individuals

A Vero cell culture–derived seasonal influenza vaccine provides consistently high levels of protection against cell culture–confirmed infection over a complete influenza season. Influenza symptoms are also less severe and of shorter duration in individuals who become infected despite vaccination