Ali, A. A. | Search bioRxiv

bioRxiv2019

Negative plant-microbiome feedback limits productivity in aquaponics

The demand for food will outpace productivity of conventional agriculture due to projected growth of the human population, concomitant with shrinkage of arable land, increasing scarcity of freshwater, and a rapidly changing climate. Efforts to increase conventional agricultural output come with significant environmental impacts stemming from deforestation and excessive use of chemicals, including soil salinization, erosion, and nutrient runoffs. While aquaponics has potential to sustainably supplement food production with minimal environmental impact, there is a need to better characterize the complex interplay between the various components (fish, plant, microbiome) of these systems to optimize scale up and productivity. For instance, much of our knowledge of beneficial and detrimental microbial communities vis-a-vis crop productivity comes from studies on plant-microbiome interactions in soil. Here, we investigated how the practice of continued transfer of microbial communities from pre-existing systems might promote or impede productivity of aquaponics. Specifically, we monitored plant growth phenotypes, water chemistry, and microbiome composition of rhizospheres, biofilters, and fish feces over 61-days of lettuce (Lactuca sativa) growth in aquaponic systems inoculated with bacteria that were either commercially sourced or originating from a pre-existing aquaponic system. Strikingly, L. sativa plant and root growth was significantly reduced across all replicates inoculated with the established microbiome. Further analyses revealed the reduced productivity was potentially a consequence of plant-specific pathogen enrichment, including Pseudomonas, through transfer of microbiomes from pre-existing systems - a phenomenon consistent with negative feedbacks in soil ecology. These findings underscore the need for diagnostic tools to monitor microbiome composition, detect negative feedbacks early, and minimize pathogen accumulation in aquaponic systems.

microbiology↗

bioRxiv2019

Computational vaccinology approach: Designing an efficient multi-epitope peptide vaccine against Cryptococcus neoformans var. grubii heat shock 70KDa protein

IntroductionCryptococcosis is a ubiquitous opportunistic fungal disease caused by Cryptococcus neoformans var. grubii. It has high global morbidity and mortality among HIV patients and none-HIV carriers with 99% and 95% respectively. Furthermore, the increasing prevalence of undesired toxicity profile of antifungal, multi-drug resistant organism, and the scarcity of FDA authorized vaccines, where the hallmark in the present days. This study was undertaken to design a reliable multi-epitope peptide vaccine against highly conserved immunodominant heat shock 70KDa protein of Cryptococcus neoformans var. grubii that covers a considerable digit of the world population through implementing computational vaccinology approach. Materials and MethodsA total of 38 Sequences of Cryptococcus neoformans var. grubiis heat shock 70KDa protein were retrieved from NCBI protein database. Different prediction tools were used to analyze the aforementioned protein at Immune Epitope Database (IEDB) to discriminate the most promising T-cell and B-cell epitopes. Then the proposed epitopes were subjected to Population coverage analysis tool to compute global populations coverage. Finally, the projected epitopes were ranked based on their scores and binding modes through using Moe 2007 program. Outstanding Results and ConclusionOur prime vaccine candidate was a putative ten promising epitopes (ANYVQASEK, NYVQASEK, KSVEKPAS, TPQQPPAQ, YVYDTRGKL, FYRQGAFEL, FTQLVAAYL, FFGGKVLNF, FDYALVQHF, and FINAQLVDV). Together, these epitopes are forecasted to trigger T lymphocytes, B lymphocytes, and immunological memory with overall population coverage above 90%. Accordingly, our in silico vaccine is expected to be the future multi-epitope peptide vaccine against Cryptococcus neoformans var. grubiis heat shock 70KDa protein that covers a significant figure of the entire world citizens. Therefore, there is a definite need for experimental validation for the carefully chosen vaccine candidates in vitro and in vivo to fortify their antigenic and immunogenic potentials. Additionally, further computational studies are needed to be conducted in pathogens-derived Heat shock 70KDa protein family, as it believed to find universal epitopes that might be overlapped with other pathogens-derived Hsp70.

bioinformatics↗