Sensitivity of antibiotic resistant coagulase-negative staphylococci to antiseptic piсloxydin

Background. Coagulase-negative staphylococci (CNS), primarily Staphylococcus epidermidis, predominate in the normal microflora of the eye. However, due to irrational antibiotic therapy, resistant strains are widely distributed among CNS. Aim. To study the sensitivity of the antibiotic resistant CNS isolates to picloxydine, an antiseptic. Methods. The species, sensitivity to antibiotics and picloxydine were determined for 39 isolates of bacteria obtained from the conjunctival swabs. The cells morphology under the antiseptics influence was studied by electron microscopy. Results. 33 isolates of S. epidermidis (17 sensitive or resistant to drugs of no more than 2 classes of antibiotics and 16 MDR), 2 S. haemolyticus (1 resistant to 2 classes of antibiotics and 1 MDR), 3 S. hominis (1 sensitive and 2 MDR), 1 S. caprae (MDR) were characterized. In in vitro tests, picloxydine showed high efficiency in suppressing the growth of staphylococci regardless of their sensitivity to antibiotics, as well as bactericidal activity at concentrations of 15.631.2 g/ml, close to those of chlorhexidine. At these concentrations, the antiseptic had a destructive effect on the surface structures of bacterial cells. Conclusion. The picloxydine antiseptic is equally effective against antibiotic- sensitive and antibiotic-resistant coagulase-negative staphylococci

Updating the approaches to define susceptibility and resistance to anti-tuberculosis agents: implications for diagnosis and treatment

11 páginas, 2 figuras, 1 tablaInappropriately high breakpoints have resulted in systematic false-susceptible AST results to anti-TB drugs. MIC, PK/PD and clinical outcome data should be combined when setting breakpoints to minimise the emergence and spread of antimicrobial resistance.I. Comas was supported by PID2019-104477RB-I00 from the Spanish Science Ministry and by ERC (CoG 101001038)Peer reviewe

Approaches to gene pool conservation of medicinal plant Oxytropis lanata (Pall.) DC. (Fabaceae)

In order to preserve the gene pool of medicinal plant Oxytropis lanata (Pall.) DC. we analyzed allozyme polymorphism and identified reliable and informative marker enzyme systems of this species; also we studied the response of seeds to deep freezing in liquid nitrogen (–196 ºС). Population has an average level of polymorphism (P95 = 41,2 %, P99 = 52,9 %, A = 1,58, Ho = 0,158, He = 0,171) in general typical for herbaceous legumes, and can serve as a source of material for gene pool conservation of the species. Deep freezing has not led to the death of the seeds; it was marked stimulatory effect of ultralow temperatures, expressed as an acceleration of germination and sharp increase of germinability (98,6 ± 2,3 %) compared to the control (12,0 ± 3,5 %) that is associated with overcoming physical dormancy. There were no abnormalities in the development of seedlings from seeds passed cryopreservation

Mechanical properties of tubulin intra- and inter-dimer interfaces and their implications for microtubule dynamic instability.

Thirteen tubulin protofilaments, made of αβ-tubulin heterodimers, interact laterally to produce cytoskeletal microtubules. Microtubules exhibit the striking property of dynamic instability, manifested in their intermittent growth and shrinkage at both ends. This behavior is key to many cellular processes, such as cell division, migration, maintenance of cell shape, etc. Although assembly and disassembly of microtubules is known to be linked to hydrolysis of a guanosine triphosphate molecule in the pocket of β-tubulin, detailed mechanistic understanding of corresponding conformational changes is still lacking. Here we take advantage of the recent generation of in-microtubule structures of tubulin to examine the properties of protofilaments, which serve as important microtubule assembly and disassembly intermediates. We find that initially straight tubulin protofilaments, relax to similar non-radially curved and slightly twisted conformations. Our analysis further suggests that guanosine triphosphate hydrolysis primarily affects the flexibility and conformation of the inter-dimer interface, without a strong impact on the shape or flexibility of αβ-heterodimer. Inter-dimer interfaces are significantly more flexible compared to intra-dimer interfaces. We argue that such a difference in flexibility could be key for distinct stability of the plus and minus microtubule ends. The higher flexibility of the inter-dimer interface may have implications for development of pulling force by curving tubulin protofilaments during microtubule disassembly, a process of major importance for chromosome motions in mitosis

On one-sided estimates for row-finite systems of ordinary differential equations

summary:We prove an existence and uniqueness theorem for row-finite initial value problems. The right-hand side of the differential equation is supposed to satisfy a one-sided matrix Lipschitz condition with a quasimonotone row-finite matrix which has an at most countable spectrum