Cryptococcus Strains with Different Pathogenic Potentials Have Diverse Protein Secretomes

Secreted proteins are the frontline between the host and pathogen. In mammalian hosts, secreted proteins enable invasive infection and can modulate the host immune response. Cryptococcosis, caused by pathogenic Cryptococcus species, begins when inhaled infectious propagules establish to produce pulmonary infection, which, if not resolved, can disseminate to the central nervous system to cause meningoencephalitis. Strains of Cryptococcus species differ in their capacity to cause disease, and the mechanisms underlying this are not well understood. To investigate the role of secreted proteins in disease, we determined the secretome for three genome strains of Cryptococcus species, including a hypovirulent and a hypervirulent strain of C. gattii and a virulent strain of C. neoformans. Sixty-seven unique proteins were identified, with different numbers and types of proteins secreted by each strain. The secretomes of the virulent strains were largely limited to proteolytic and hydrolytic enzymes, while the hypovirulent strain had a diverse secretome, including non-conventionally secreted canonical cytosolic and immunogenic proteins that have been implicated in virulence. The hypovirulent strain cannot establish pulmonary infection in a mouse model, but strains of this genotype have caused human meningitis. To directly test brain infection, we used intracranial inoculation and found that the hypovirulent strain was substantially more invasive than its hypervirulent counterpart. We suggest that immunogenic proteins secreted by this strain invoke a host response that limits pulmonary infection but that there can be invasive growth and damage if infection reaches the brain. Given their known role in virulence, it is possible that non-conventionally secreted proteins mediate this process.     

Computational and Pharmacological Studies on the Antioxidant,Thrombolytic, Anti-Inflammatory,and Analgesic Activity of Molineria capitulata

Molineria capitulata is an ornamental plant that has traditionally been used to treat several chronic diseases. The present study was designed to examine the antioxidant, cytotoxic, thrombolytic, anti-inflammatory, and analgesic activities of a methanolic extract of M. capitulata leaves (MEMC) using both experimental and computational models. Previously established protocols were used to perform qualitative and quantitative phytochemical screening in MEMC. A computational study, including molecular docking and ADME/T analyses, was performed. The quantitative phytochemical analysis revealed the total phenolic and flavonoid contents as 148.67 and 24 mg/g, respectively. Antioxidant activity was assessed by examining the reducing power of MEMC, resulting in absorbance of 1.87 at 400 µg/mL, demonstrating a strong reduction capacity. The extract exhibited significant protection against blood clotting and showed the highest protein denaturation inhibition at 500 µg/mL. In both the acetic acid-induced writhing and formalin-induced paw-licking models, MEMC resulted in significant potential pain inhibition in mice. In the computational analysis, 4-hydroxybenzaldehyde, orcinol glucoside, curcapital, crassifogenin C, and 2,6-dimethoxy-benzoic acid displayed a strong predictive binding affinity against the respective receptors. These findings indicated that M. capitulata possesses significant pharmacological activities to an extent supported by computational studies.     

Zebrafish TARP Cacng2 is required for the expression and normal development of AMPA receptors at excitatory synapses

Fast excitatory synaptic transmission in the CNS is mediated by the neurotransmitter glutamate, binding to and activating AMPA receptors (AMPARs). AMPARs are known to interact with auxiliary proteins that modulate their behavior. One such family of proteins is the transmembrane AMPA receptor‐related proteins, known as TARPs. Little is known about the role of TARPs during development, or about their function in non‐mammalian organisms. Here we report the presence of TARPs, specifically the prototypical TARP, stargazin, in developing zebrafish. We find that zebrafish express two forms of stargazin, Cacng2a and Cacng2b from as early as 12‐h post fertilization (hpf). Knockdown of Cacng2a and Cacng2b via splice‐blocking morpholinos resulted in embryos that exhibited deficits in C‐start escape responses, showing reduced C‐bend angles, smaller tail velocities and aberrant C‐bend turning directions. Injection of the morphants with Cacng2a or 2b mRNA rescued the morphological phenotype and the synaptic deficits. To investigate the effect of reduced Cacng2a and 2b levels on synaptic physiology, we performed whole cell patch clamp recordings of AMPA mEPSCs from zebrafish Mauthner cells. Knockdown of Cacng2a results in reduced AMPA currents and lower mEPSC frequencies, whereas knockdown of Cacng2b displayed no significant change in mEPSC amplitude or frequency. Non‐stationary fluctuation analysis confirmed a reduction in the number of active synaptic receptors in the Cacng2a but not in the Cacng2b morphants. Together, these results suggest that Cacng2a is required for normal trafficking and function of synaptic AMPARs, while Cacng2b is largely non‐functional with respect to the development of AMPA synaptic transmission. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 76: 487–506, 2016     

Drought-inducible expression of <Emphasis Type="Italic">Hv</Emphasis>-miR827 enhances drought tolerance in transgenic barley

Drought is one of the major abiotic stresses reducing crop yield. Since the discovery of plant microRNAs (miRNAs), considerable progress has been made in clarifying their role in plant responses to abiotic stresses, including drought. miR827 was previously reported to confer drought tolerance in transgenic Arabidopsis. We examined barley (Hordeum vulgare L. ‘Golden Promise’) plants over-expressing miR827 for plant performance under drought. Transgenic plants constitutively expressing CaMV-35S::Ath-miR827 and drought-inducible Zm-Rab17::Hv-miR827 were phenotyped by non-destructive imaging for growth and whole plant water use efficiency (WUE_wp). We observed that the growth, WUE_wp, time to anthesis and grain weight of transgenic barley plants expressing CaMV-35S::Ath-miR827 were negatively affected in both well-watered and drought-treated growing conditions compared with the wild-type plants. In contrast, transgenic plants over-expressing Zm-Rab17::Hv-miR827 showed improved WUE_wp with no growth or reproductive timing change compared with the wild-type plants. The recovery of Zm-Rab17::Hv-miR827 over-expressing plants also improved following severe drought stress. Our results suggest that Hv-miR827 has the potential to improve the performance of barley under drought and that the choice of promoter to control the timing and specificity of miRNA expression is critical.     

NMDA receptors on zebrafish Mauthner cells require CaMKII‐α for normal development

Calcium/calmodulin dependent protein kinase 2 (CaMKII) is a multifunctional protein that is highly enriched in the synapse. It plays important roles in neuronal functions such as synaptic plasticity, synaptogenesis, and neural development. Gene duplication in zebrafish has resulted in the occurrence of seven CaMKII genes (camk2a, camk2b1, camk2b2, camk2g1, camk2g2, camk2d1, and camk2d2) that are developmentally expressed. In this study, we used single cell, real‐time quantitative PCR to investigate the expression of CaMKII genes in individual Mauthner cells (M‐cells) of 2 days post fertilization (dpf) zebrafish embryos. We found that out of seven different CaMKII genes, only the mRNA for CaMKII‐α was expressed in the M‐cell at detectable levels, while all other isoforms were undetectable. Morpholino knockdown of CaMKII‐α had no significant effect on AMPA synaptic currents (mEPSCs) but decreased the amplitude of NMDA mEPSCs. NMDA events exhibited a biexponential decay with τ_fast ≈ 30 ms and τ_slow ≈ 300 ms. Knockdown of CaMKII‐α specifically reduced the amplitude of the slow component of the NMDA‐mediated currents (mEPSCs), without affecting the fast component, the frequency, or the kinetics of the mEPSCs. Immunolabelling of the M‐cell showed increased dendritic arborizations in the morphants compared with controls, and knockdown of CaMKII‐α altered locomotor behaviors of touch responses. These results suggest that CaMKII‐α is present in embryonic M‐cells and that it plays a role in the normal development of excitatory synapses. Our findings pave the way for determining the function of specific CaMKII isoforms during the early stages of M‐cell development. © 2014 Wiley Periodicals, Inc. Develop Neurobiol 75: 145–162, 2015     

Identification and detoxification of glycolaldehyde,an unattended bioethanol fermentation inhibitor

Although there have been approximately 60 chemical compounds identified as potent fermentation inhibitors in lignocellulose hydrolysate, our research group recently discovered glycolaldehyde as a key fermentation inhibitor during second generation biofuel production. Accordingly, we have developed a yeast S. cerevisiae strain exhibiting tolerance to glycolaldehyde. During this glycolaldehyde study, we established novel approaches for rational engineering of inhibitor-tolerant S. cerevisiae strains, including engineering redox cofactors and engineering the SUMOylation pathway. These new technical dimensions provide a novel platform for engineering S. cerevisiae strains to overcome one of the key barriers for industrialization of lignocellulosic ethanol production. As such, this review discusses novel biochemical insight of glycolaldehyde in the context of the biofuel industry.     

Plant Growth-Promoting Rhizobacteria-Mediated Adaptive Responses of Plants Under Salinity Stress

In this recent era, several approaches have been developed to alleviate the adverse effects of salinity stress in different plants. However, some of them are not eco-friendly. In this context, evolving sustainable approaches which enhance the productivity of saline soil without harming the environment are necessary. Many recent studies showed that plant growth-promoting rhizobacteria (PGPR) are known to confer salinity tolerance to plants. Salt-stressed plants inoculated with PGPR enhance the growth and productivity of crops by reducing oxidative damage, maintaining ionic homeostasis, enhancing antioxidant machinery, and regulating gene expressions. The PGPR also regulates the photosynthetic attributes such as net photosynthetic rate, chlorophyll, and carotenoid contents and enhances the salinity tolerance to plants. Moreover, PGPR has a great role in the enhancement of phytohormones and secondary metabolites synthesis in plants under salt stress. This review summarizes the current reports of the application of PGPR in plants under salt stress and discusses the PGPR-mediated mechanisms in plants of salt tolerance. This review also discusses the potential role of PGPR in cross-talk with phytohormones and secondary metabolites to alleviate salt stress and highlights the research gaps where further research is needed.