Revisiting implementation of multiple natural enemies in pest management.

A major goal of biological control is the reduction and/or eradication of pests using various natural enemies, in particular, via deliberate infection of the target species by parasites. To enhance the biological control, a promising strategy seems to implement a multi-enemy assemblage rather than a single control agent. Although a large body of theoretical studies exists on co-infections in epidemiology and ecology, there is still a big gap in modelling outcomes of multi-enemy biological control. Here we theoretically investigate how the efficiency of biological control of a pest depends on the number of natural enemies used. We implement a combination of eco-epidemiological modelling and the Adaptive Dynamics game theory framework. We found that a progressive addition of parasite species increases the evolutionarily stable virulence of each parasite, and thus enhances the mortality of the target pest. However, using multiple enemies may have only a marginal effect on the success of biological control, or can even be counter-productive when the number of enemies is excessive. We found the possibility of evolutionary suicide, where one or several parasite species go extinct over the course of evolution. Finally, we demonstrate an interesting scenario of coexistence of multiple parasites at the edge of extinction.

Dendrimers: A New Race of Pharmaceutical Nanocarriers.

Dendrimers are nanosized, symmetrical molecules in which a small atom or group of atoms is surrounded by the symmetric branches known as dendrons. The structure of dendrimers possesses the greatest impact on their physical and chemical properties. They grow outwards from the core-shell which further reacts with monomers having one reactive or two dormant molecules. Dendrimers' unique characteristics such as hyperbranching, well-defined spherical structure, and high compatibility with the biological systems are responsible for their wide range of applications including medical and biomedical areas. Particularly, the dendrimers' three-dimensional structure can incorporate a wide variety of drugs to form biologically active drug conjugates. In this review, we focus on the synthesis, mechanism of drug encapsulations in dendrimers, and their wide applications in drug delivery.

Synthesis, characterization, and antimicrobial evaluation of novel 5-benzoyl-N-substituted amino- and 5-benzoyl-N-sulfonylamino-4-alkylsulfanyl-2-pyridones.

The present research describes the synthesis of novel 5-benzoyl-N-substituted-amino- and 5-benzoyl-N-sulfonylamino-4-alkylsulfanyl-2-pyridones 5a-c and 6a-c via the reaction of 2-benzoyl-3,3-bis(alkylthio)acrylonitriles 2a-c with N-cyanoacetohydrazide 3 and cyanoaceto-N-phenylsulfonylhydrazide 4, respectively. Also, the reactivity of the compounds 5a-c toward hydrazine hydrate to give product 1H-pyrazolo[4,3-c]pyridine derivative 7 was studied. In addition, the reactivity of the 2a-c toward 1-cyanoacetyl-4 arylidenesemicarbazides 8a-c afforded 3,5-dihydro[1,2,4]triazolo[1,5-a]pyridine-6-carbonitrile derivatives (12-14)a-c, which reacted with hydrazine hydrate to give 3H-pyrazolo[4,3-c][1,2,4]triazolo[1,5-a]pyridine-6-carbonitrile derivatives 15a-c. The structures of the new products were characterized based on 1H nuclear magnetic resonance, 13C nuclear magnetic resonance, infrared, mass-spectroscopy, and elemental analyses. The products were screened in vitro for their antibacterial and antifungal activity properties.