Characterization of the host-defense peptides from skin secretions of Merlin's clawed frog Pseudhymenochirus merlini: Insights into phylogenetic relationships among the Pipidae

The family Pipidae comprises the genera Hymenochirus, Pipa, Pseudhymenochirus, Silurana, and Xenopus but phylogenetic relationships within the family are unclear. Peptidomic analysis of norepinephrine-stimulated skin secretions from Pseudhymenochirus merlini Chabanaud, 1920, the single species within the genus Pseudhymenochirus, led to identification of 13 host-defense peptides with antimicrobial activity. Two peptides (hymenochirin-1Pa and -1Pb) show structural similarity to hymenochirin-1B from Hymenochirus boettgeri and eight peptides (hymenochirin-5Pa, -5Pb, -5Pc, -5Pd, -5Pe, -5Pf, 5Pg and -5Ph) are structurally similar to each other and to hymenochirin-5B from H. boettgeri. Two peptides differing by a single amino acid (IKIPSFFRNILKKVGKEAVSLM/I AGALKQS), termed pseudhymenochirin-1Pa and -1Pb, and pseudhymenochirin-2Pa (GIFPIFAKLLGKVIKVASSLISKGRTE) do not resemble host-defense peptides previously isolated from pipid frogs. Hymenochirin-5Pe was the most abundant peptide in the secretions and hymenochirin-1Pa the most potent against Staphylococcus aureus (MIC = 2.5 μM) and Escherichia coli (MIC = 10 μM). The data support a close phylogenetic relationship between Hymenochirus and Pseudhymenochirus that is distinct from the Xenopodinae (Xenopus + Silurana) clade with Pipa sister-group to all other extant pipids.     

An approach for the improved immobilization of penicillin G acylase onto macroporous poly(glycidyl methacrylate‐co‐ethylene glycol dimethacrylate) as a potential industrial biocatalyst

The use of penicillin G acylase (PGA) covalently linked to insoluble carrier is expected to produce major advances in pharmaceutical processing industry and the enzyme stability enhancement is still a significant challenge. The objective of this study was to improve catalytic performance of the covalently immobilized PGA on a potential industrial carrier, macroporous poly(glycidyl methacrylate‐co‐ethylene glycol dimethacrylate) [poly(GMA‐co‐EGDMA)], by optimizing the copolymerization process and the enzyme attachment procedure. This synthetic copolymer could be a very promising alternative for the development of low‐cost, easy‐to‐prepare, and stable biocatalyst compared to expensive commercially available epoxy carriers such as Eupergit or Sepabeads. The PGA immobilized on poly(GMA‐co‐EGDMA) in the shape of microbeads obtained by suspension copolymerization appeared to have higher activity yield compared to copolymerization in a cast. Optimal conditions for the immobilization of PGA on poly(GMA‐co‐EGDMA) microbeads were 1 mg/mL of PGA in 0.75 mol/L phosphate buffer pH 6.0 at 25°C for 24 h, leading to the active biocatalyst with the specific activity of 252.7 U/g dry beads. Chemical amination of the immobilized PGA could contribute to the enhanced stability of the biocatalyst by inducing secondary interactions between the enzyme and the carrier, ensuring multipoint attachment. The best balance between the activity yield (51.5%), enzyme loading (25.6 mg/g), and stability (stabilization factor 22.2) was achieved for the partially modified PGA. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 32:43–53, 2016     

Análisis del impacto presupuestal en Colombia de la prueba de HPV con genotipificación comparada con la citología

Introduction:

The detection of the human papillomavirus (HPV) through the combination of the HPV test and other techniques such as cytology has impacted the detection and timely treatment of lesions associated with cervical cancer.

Objective:

To estimate the budgetary impact of the strategy of early detection of HPV with DNA test genotyping with reflex cytology versus conventional cytology in women aged 30 to 65 years attending the cervical cancer screening program at a health benefit managing entity in Colombia.

Materials and methods:

Using a decision tree and a Markov model, the clinical implications and direct costs of screening, diagnosis, and treatment were estimated in a cohort of women. The analysis considered two screening cycles and their annual costs. The data on the prevalence of clinical results and the costs were taken from the health managing entity. The information on the progression, persistence, and regression of the health states were taken from the ATHENA study.

Results:

The screening scheme with the HPV test, genotyping, and reflex cytology compared to conventional cytology was cost-saving. The average cost per screening cycle with the HPV test was estimated at COP $ 129,201,363 and with cytology at COP $ 186,309,952, i.e., a saving of COP $ 57,108,589 (30.7%).

Conclusion:

The implementation of the screening strategy under evaluation suggests prospective savings derived from the early detection of health states associated with the development of cervical cancer.     

Detailed Characterization of Brain Dysfunction in a Long-Term Rodent Model of Critical Illness

Neurochemical Research - Critical illness encompasses a wide spectrum of life-threatening clinical conditions requiring intensive care. Our objective was to evaluate cognitive, inflammatory and...     

Genetics of host response to Leishmania tropica in mice - different control of skin pathology, chemokine reaction, and invasion into spleen and liver

Background

Leishmaniasis is a disease caused by protozoan parasites of genus Leishmania. The frequent involvement of Leishmania tropica in human leishmaniasis has been recognized only recently. Similarly as L. major, L. tropica causes cutaneous leishmaniasis in humans, but can also visceralize and cause systemic illness. The relationship between the host genotype and disease manifestations is poorly understood because there were no suitable animal models.

Methods

We studied susceptibility to L. tropica, using BALB/c-c-STS/A (CcS/Dem) recombinant congenic (RC) strains, which differ greatly in susceptibility to L. major. Mice were infected with L. tropica and skin lesions, cytokine and chemokine levels in serum, and parasite numbers in organs were measured.

Principal Findings

Females of BALB/c and several RC strains developed skin lesions. In some strains parasites visceralized and were detected in spleen and liver. Importantly, the strain distribution pattern of symptoms caused by L. tropica was different from that observed after L. major infection. Moreover, sex differently influenced infection with L. tropica and L. major. L. major-infected males exhibited either higher or similar skin pathology as females, whereas L. tropica-infected females were more susceptible than males. The majority of L. tropica-infected strains exhibited increased levels of chemokines CCL2, CCL3 and CCL5. CcS-16 females, which developed the largest lesions, exhibited a unique systemic chemokine reaction, characterized by additional transient early peaks of CCL3 and CCL5, which were not present in CcS-16 males nor in any other strain.

Conclusion

Comparison of L. tropica and L. major infections indicates that the strain patterns of response are species-specific, with different sex effects and largely different host susceptibility genes.