Project description:Enrichments with labeled CH4 and NO2 were conducted to test microbial community correlations and constrain potential metabolic interactions between methanotrophs and other one-carbon utilizing microorganisms under low O2 conditions
2023-01-14 | PXD011287 | Pride
Project description:Analysis of Microalgae-Methanotrophs Mixed Culture in Membrane Photobioreactor
Project description:Managing tradeoffs through gene regulation is believed to maintain resilience of a microbial community in a fluctuating resource environment. To investigate this hypothesis we imposed a fluctuating environment that required the sulfate-reducing generalist Desulfovibrio vulgaris to manage tradeoffs associated with repeated ecologically-relevant shifts between retaining metabolic independence (active capacity for sulfate respiration) and becoming metabolically specialized to a mutualistic association with the hydrogen consuming Methanococcus maripaludis. Strikingly, the microbial community became progressively less proficient at restoring the environmentally-relevant physiological state after each perturbation. Most cultures collapsed within 3-7 shifts with only a few collapsing later. We demonstrate that the collapse was caused by conditional gene regulation, which drove precipitous decline in intracellular abundance of essential transcripts and proteins, imposing greater energetic burden of regulation to restore function in a fluctuating environment. The microbial community collapse was rescued by a single regulatory mutation that could then potentially serve as a stepping stone for further adaptive evolution in a variable resource environment. Co-culture strains of M. maripaludis wild type and either wild type or DVU0744::Tn5 mutant of D. vulgaris strains were grown anaerobically in replicates. Samples were transitioned between syntrophic and sulfate respiratory growth conditions at early log phases.
Project description:Microbial biofertilizers were investigated for their ability to mitigate drought stress and enhance resilience in Andrographis paniculata. High-performance liquid chromatography (HPLC) analysis revealed that microbial biofertilizer significantly increased andrographolide content, a key bioactive compound, even under drought stress.
Project description:Managing tradeoffs through gene regulation is believed to maintain resilience of a microbial community in a fluctuating resource environment. To investigate this hypothesis we imposed a fluctuating environment that required the sulfate-reducing generalist Desulfovibrio vulgaris to manage tradeoffs associated with repeated ecologically-relevant shifts between retaining metabolic independence (active capacity for sulfate respiration) and becoming metabolically specialized to a mutualistic association with the hydrogen consuming Methanococcus maripaludis. Strikingly, the microbial community became progressively less proficient at restoring the environmentally-relevant physiological state after each perturbation. Most cultures collapsed within 3-7 shifts with only a few collapsing later. We demonstrate that the collapse was caused by conditional gene regulation, which drove precipitous decline in intracellular abundance of essential transcripts and proteins, imposing greater energetic burden of regulation to restore function in a fluctuating environment. The microbial community collapse was rescued by a single regulatory mutation that could then potentially serve as a stepping stone for further adaptive evolution in a variable resource environment.
Project description:Analysis of transcript abundance estimates as a function of child soldier status, PTSD symptoms, and psychological resilience. Gene expression profiling was conducted on dried blood spot (DBS) samples collected from community dwelling adolescents and young adults in Nepal. Approximatley half of the sample were former child soldiers in the Nepal People's War and the other half were demographically similiar civilian non-combatants. In addition to basic demographic characteristics (age, sex, ethnic minority status, social caste status, education level), participants were also assessed on syptoms of post-traumatic stress (PTS, assessed by a culturally adapted version of The Child PTSD Symptom Scale; Kohrt BA, et al. (2011) Validation of cross-cultural child mental health and psychosocial research instruments: adapting the Depression Self-Rating Scale and Child PTSD Symptom Scale in Nepal. BMC Psychiatry 11(1):e127, with higher values indicating greater PTSD symptoms) and psychological resilience (assessed by a culturally adapted version of the Resilience Scale; Wagnild GM & Young HM (1993) Development and psychometric evaluation of the Resilience Scale. Journal of Nursing Measurement, with higher values indicating greater resilience). Dichotomous variables were coded 0=no/absent and 1=yes/present. Valid gene expression data are available for 254 samples.
Project description:Microarrays have become established tools for describing microbial systems, however the assessment of expression profiles for environmental microbial communities still presents unique challenges. Notably, the concentration of particular transcripts are likely very dilute relative to the pool of total RNA, and PCR-based amplification strategies are vulnerable to amplification biases and the appropriate primer selection. Thus, we apply a signal amplification approach, rather than template amplification, to analyze the expression of selected lignin-degrading enzymes in soil. Controls in the form of known amplicons and cDNA from Phanerochaete chrysosporium were included and mixed with the soil cDNA both before and after the signal amplification in order to assess the dynamic range of the microarray. We demonstrate that restored prairie soil expresses a diverse range of lignin-degrading enzymes following incubation with lignin substrate, while farmed agricultural soil does not. The mixed additions of control cDNA with soil cDNA indicate that the mixed biomass in the soil does interfere with low abundance transcript changes, nevertheless our microarray approach consistently reports the most robust signals. Keywords: comparative analysis, microbial ecology, soil microbial communities