Living in an extremely polluted environment: Clues from the genome of melanin-producing Aeromonas salmonicida subsp. pectinolytica 34melT

Aeromonas salmonicida subsp. pectinolytica 34mel(T) can be considered an extremophile due to the characteristics of the heavily polluted river from which it was isolated. While four subspecies of A. salmonicida are known fish pathogens, 34mel(T) belongs to the only subspecies isolated solely from the environment. Genome analysis revealed a high metabolic versatility, the capability to cope with diverse stress agents, and the lack of several virulence factors found in pathogenic Aeromonas. The most relevant phenotypic characteristics of 34mel(T) are pectin degradation, a distinctive trait of A. salmonicida subsp. pectinolytica, and melanin production. Genes coding for three pectate lyases were detected in a cluster, unique to this microorganism, that contains all genes needed for pectin degradation. Melanin synthesis in 34mel(T) is hypothesized to occur through the homogentisate pathway, as no tyrosinases or laccases were detected and the homogentisate 1,2-dioxygenase gene is inactivated by a transposon insertion, leading to the accumulation of the melanin precursor homogentisate. Comparative genome analysis of other melanogenic Aeromonas strains revealed that this gene was inactivated by transposon insertions or point mutations, indicating that melanin biosynthesis in Aeromonas occurs through the homogentisate pathway. Horizontal gene transfer could have contributed to the adaptation of 34mel(T) to a highly polluted environment, as 13 genomic islands were identified in its genome, some of them containing genes coding for fitness-related traits. Heavy metal resistance genes were also found, along with others associated with oxidative and nitrosative stresses. These characteristics, together with melanin production and the ability to use different substrates, may explain the ability of this microorganism to live in an extremely polluted environment

Aromatic amine N-oxide organometallic compounds: Searching for prospective agents against infectious diseases

In search of prospective agents against infectious diseases, 1,1′-bis(diphenylphosphino)ferrocene pyridine-2-thiolato-1-oxide M(II) hexafluorophosphate compounds [M(mpo)(dppf)](PF6), where M = palladium or platinum, were synthesized and fully characterized in the solid state and in solution using experimental and DFT computational techniques. The compounds are isomorphous and the M(II) transition metal ions are in a nearly planar trapezoidal cis-coordination bound to the pyridine-2-thiolato-1-oxide (mpo) and to the 1,1′-bis(diphenylphosphino)ferrocene molecules, both acting as bidentate ligands. Both compounds showed high cytotoxic activity on Trypanosoma cruzi and Mycobacterium tuberculosis (MTB) and acceptable selectivities towards MTB, but good to excellent selectivity index values as anti-T. cruzi compounds. The inclusion of the ferrocene moiety (dppf ligand) improved the selectivity towards the parasite when compared to the previously reported [M(mpo)2] complexes. Related to the probable mechanism of action of the complexes, molecular docking studies on modelled T. cruzi NADH-fumarate reductase (TcFR) predicted that both be very good inhibitors of the enzyme. The effect of the compounds on the enzyme activity was experimentally confirmed using T. cruzi protein extracts. According to all obtained results, both [M(mpo)(dppf)](PF6) compounds could be considered prospective anti-trypanosomal agents that deserve further research.Fil: Rodríguez Arce, Esteban. Universidad de la República; UruguayFil: Mosquillo, M. Florencia. Universidad de la República; UruguayFil: Pérez Díaz, Leticia. Universidad de la República; UruguayFil: Echeverría, Gustavo Alberto. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Piro, Oscar Enrique. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Merlino, Alicia. Universidad de la República; UruguayFil: Coitiño, E. Laura. Universidad de la República; UruguayFil: Maríngolo Ribeiro, Camila. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Leite, Clarice Q. F.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Pavan, Fernando R.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Otero, Lucía. Universidad de la República; UruguayFil: Gambino, Dinorah. Universidad de la República; Urugua

Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

Musculoskeletal Modeling to Provide Muscles and Ligaments Length Changes during Movement for Orthopaedic Surgery Planning

The estimation of muscles and ligaments behavior can be useful in orthopaedic surgery or when a functional restoration may be reached by means of soft tissues surgery, i.e. in each case a different function is necessary to be planned for a muscle. Models of the skeletal muscle system were almost used to predict the rate of muscle-tendon lengthening during the most common tasks. In this work, a more general approach is proposed, in which individual anthropometry was considered through imaging processing, and joint kinematics captured in a movement analysis laboratory was used to animate a skeletal model, with the aim of simulating the effects of different surgical solutions on the muscle system functioning. To attain this result, the integration of different technologies, models and algorithms was required. After developing a model of the musculoskeletal and ligament system, the procedures for the pre-operative planning of both hip and knee joint replacement were simulated. A surgery planning tool based on the previously created model allowed the surgeon to plan an operation through a three-dimensional visualization of bones, by defining components’ sizes and improving their positioning by taking into account not only bone geometry but also the soft tissues spanning the articulations. Since the model is defined on a specific patient, it gives the possibility to increase model’s specificity with the aim of improving planning accuracy. The use of this planning tool can be useful both in pre-operative planning and during the surgical operation because the surgeon can develop skills in performing different operation’s steps. In this work, we considered two examples based on the model of muscles, bones and ligaments that was developed. The main steps of this procedure and the preliminary results are here presented pointing out the feasibility of the planning tool and of the model itself

A musculoskeletal model of the ankle joint complex for the analysis of the dynamic behavior of an ankle prosthesis

The ankle joint complex constitutes a biomechanical system of extreme complexity. Both in case of joint arthrodesis and joint replacement, the analysis of the forces generated under dynamic conditions is crucial. In the present work, we developed a musculoskeletal model of the ankle joint complex in order to: (a) analyze the physiological movements of the ankle joints, (b) evaluate the forces experienced by ligaments, muscles and at the contacts between tibia and talus, and (c) evaluate the effects of the insertion of a modern ankle prosthesis