Rapid and Easy Modified Plate-based Screening Methods for Quantitative and Qualitative Detection of Protease Production by Fungi

Proteases constitute a significant part of cell wall-degrading enzymes (CWDEs) produced by fungal biocontrol agents and particularly crucial in mycoparasitism of fungal phytopathogens. Plate-based screening methods are routinely used for screening protease-producing microorganisms including fungi. Skim milk agar (SMA) is one of the most popular media for the detection of protease producing bacteria. However, SMA is not efficient to test fast growing fungi, because it does not give an estimation of the actual amount of secreted protease produced by fungal inocula. In the current study, the efficacy of two modified plate-screening methods, including split-SMA (SSMA) and minimal medium supplemented with skim milk (MSMW) was assessed for detection of protease production by three representative fungal strains including Trichoderma longibrachiatum strain N, Beauveria bassiana strain B and Purpureocillium lilacinum strain PL. Protease production was revealed on the three tested media by the three strains. However, the halo diameter of the fungal strains (a proxy for protease production) was the smallest on SMA. Furthermore, protease production could not be detected for T. longibrachiatum strain N on SMA due to its fast growth; while it showed the highest protease activity on both modified media compared with the other strains. According to the result of this study, the SSMA medium is an easy and more accurate method compared with the two other different methods as it displays the actual amount of protease produced by fungal strains and therefore this method is recommended for quantitative and qualitative detection of protease production by slow and fast growing fungi

The rate of facultative sex governs the number of expected mating types in isogamous species

It is unclear why sexually reproducing isogamous species frequently contain just two self-incompatible mating types. Deterministic theory suggests that since rare novel mating types experience a selective advantage (by virtue of their many potential partners), the number of mating types should consistently grow. However, in nature, species with thousands of mating types are exceedingly rare. Several competing theories for the predominance of species with two mating types exist, yet they lack an explanation for how many are possible and in which species to expect high numbers. Here, we present a theoretical null model that explains the distribution of mating type numbers using just three biological parameters: mutation rate, population size and the rate of sex. If the number of mating types results from a mutation–extinction balance, the rate of sexual reproduction plays a crucial role. If sex is facultative and rare (a very common combination in isogamous species), mating type diversity will remain low. In this rare sex regime, small fitness differences between the mating types lead to more frequent extinctions, further lowering mating type diversity. We also show that the empirical literature supports the role of drift and facultativeness of sex as a determinant of mating type dynamics

The rate of facultative sex governs the number of expected mating types in isogamous species

It is unclear why sexually reproducing isogamous species frequently contain just two self-incompatible mating types. Deterministic theory suggests that since rare novel mating types experience a selective advantage (by virtue of their many potential partners), the number of mating types should consistently grow. However, in nature, species with thousands of mating types are exceedingly rare. Several competing theories for the predominance of species with two mating types exist, yet they lack an explanation for how many are possible and in which species to expect high numbers. Here, we present a theoretical null model that explains the distribution of mating type numbers using just three biological parameters: mutation rate, population size and the rate of sex. If the number of mating types results from a mutation–extinction balance, the rate of sexual reproduction plays a crucial role. If sex is facultative and rare (a very common combination in isogamous species), mating type diversity will remain low. In this rare sex regime, small fitness differences between the mating types lead to more frequent extinctions, further lowering mating type diversity. We also show that the empirical literature supports the role of drift and facultativeness of sex as a determinant of mating type dynamics

ITS sequence data and morphology differentiate Cytospora chrysosperma associated with trunk disease of grapevine in northern Iran

Trunk diseases are potential threats for the grapevine industry owing to the worldwide incidence and economic impact of the diseases. Several fungal groups are known to be involved in these diseases. In a survey on grapevine trunk diseases in northern Iran, Cytospora isolates were repeatedly recovered from vines showing decline symptoms. The symptoms appeared as pale brown to brown streaks in longitudinal cuts of shoots. The morphological and cultural characteristics of the isolates were in agreement with the description of Cytospora chrysosperma. Sequence data of the ITS-rDNA region was used to further confirm the identity of the species. Phylogenetic analysis based on the sequence data obtained in this study and the sequences from GenBank, confirmed the morphological identification. Our isolates were clustered together with C. chrysosperma isolates known from other woody host plant species. The pathogenicity assay on detached shoots of grapevines induced the same symptoms as was observed in field conditions. Although, C. chrysosperma is known from several woody hosts in Iran, the occurrence of this species on grapevines showing decline symptoms is new. The economic impact, distribution, and degree of involvement of C. chrysosperma in decline of vines in other regions of Iran remains to be studied

Isolation and identification of Streptomyces sp. Act4Zk, a good producer of Staurosporine and some derivatives.

In this study, strain Streptomyces sp. Act4Zk was isolated based on a method developed for the isolation of myxobacteria. Due to the low efficiency of the majority of conventional DNA extraction techniques, for molecular identification of the strain Streptomyces sp. Act4Zk, a new technique for DNA extraction of Actinobacteria was developed. In order to explore potential bioactivities of the strain, extracts of the fermented broth culture were prepared by an organic solvent (i.e. ethyl acetate) extraction method using. These ethyl acetate extracts were subjected to HPLC fractionation against standard micro-organisms, followed by LC/MS analysis. Based on morphological, physiological, biochemical and 16S rRNA gene sequence data, strain Streptomyces sp. Act4Zk is likely to be a new species of Streptomyces, close to Streptomyces genecies and Streptomyces roseolilacinus. Antimicrobial assay indicated high antifungal activity as well as antibacterial activity against Mycobacterium smegmatis and Gram-positive bacteria for the new strain. HPLC and LC/MS analyses of the extracts led to the identification of three different compounds and confirmed our hypothesis that the interesting species of the genus Streptomyces being a good producer of staurosporine and some derivatives

Gadolinium nanoparticles as diagnostic and therapeutic agents: Their delivery systems in magnetic resonance imaging and neutron capture therapy

Abstract Gadolinium (Gd) chelates have been widely used as contrast agent in magnetic resonance imaging (MRI). In addition to using MRI, they are interesting, as a radiosensitizer, in neutron capture therapy (NCT). However, the poor selective tissue labeling and localization provided by conventional molecular Gd chelates have confined success in both MRI and NCT applications. To encapsulate Gd into nanoparticulate materials can be considered as a method to overcome these limitations. In this regard, developing various carrier systems have increased the sensitivity and improving the targetability of the contrast agents. In this review article, an overview of the delivery systems of Gd nanoparticles in the MRI and NCT would be mentioned. Keywords Gadolinium Nanoparticle MRI NCT Delivery system

Folic acid functionalized nanoparticles as pharmaceutical carriers in drug delivery systems

Conventional chemotherapeutic approaches in cancer therapy such as surgery, chemotherapy, and radiotherapy have several disadvantages due to their nontargeted distributions in the whole body. On the other hand, nanoparticles (NPs) based therapies are remarkably progressing to solve several limitations of conventional drug delivery systems (DDSs) including nonspecific biodistribution and targeting, poor water solubility, weak bioavailability and biodegradability, low pharmacokinetic properties, and so forth. The enhanced permeability and retention effect escape from P-glycoprotein trap in cancer cells as a passive targeting mechanism, and active targeting strategies are also other most important advantages of NPs in cancer diagnosis and therapy. Folic acid (FA) is one of the biologic molecules which has been targeted overexpressed-folic acid receptor (FR) on the surface of cancer cells. Therefore, conjugation of FA to NPs most easily enhances the FR-mediated targeting delivery of therapeutic agents. Here, the recent works in FA which have been decorated NPs-based DDSs are discussed and cancer therapy potency of these NPs in clinical trials are presented. © 2019 Wiley Periodicals, Inc