A Bayesian approach to modeling phytoplankton population dynamics from size distribution time series

The rates of cell growth, division, and carbon loss of microbial populations are key parameters for understanding how organisms interact with their environment and how they contribute to the carbon cycle. However, the invasive nature of current analytical methods has hindered efforts to reliably quantify these parameters. In recent years, size-structured matrix population models (MPMs) have gained popularity for estimating division rates of microbial populations by mechanistically describing changes in microbial cell size distributions over time. Motivated by the mechanistic structure of these models, we employ a Bayesian approach to extend size-structured MPMs to capture additional biological processes describing the dynamics of a marine phytoplankton population over the day-night cycle. Our Bayesian framework is able to take prior scientific knowledge into account and generate biologically interpretable results. Using data from an exponentially growing laboratory culture of the cyanobacterium Prochlorococcus, we isolate respiratory and exudative carbon losses as critical parameters for the modeling of their population dynamics. The results suggest that this modeling framework can provide deeper insights into microbial population dynamics provided by size distribution time-series data.

On the Ecological Significance of Phenotypic Heterogeneity in Microbial Populations Undergoing Starvation

Nongenetic cell heterogeneity is present in glucose-starved yeast populations in the form of quiescent (Q) and nonquiescent (NQ) phenotypes. There is evidence that Q cells help the population survive long starvation.

Production And Fusion Of Antimicrobial Agents With Bio Plastic Using Palmyra Sprout

The problems linked to plastic wastes have led to the development of biodegradable plastics. More specifically, biodegradable bioplastics are the polymers that are mineralized into carbon dioxide, methane, water, inorganic compounds, or biomass through the enzymatic action of specific microorganisms. They could, therefore, be a suitable and environmentally friendly substitute to conventional petrochemical plastics. The physico-chemical structure of the biopolymers, the environmental conditions, as well as the microbial populations to which the bioplastics are exposed to are the most influential factors to biodegradation. The Borassus flabellifer is a tall and erect palm, with large, fan-shaped leaves which are quite unlike the pinnate leaves of other palms. Borassus is from a Greek word describing the leathery covering of the fruit and flabellifer means “fan bearer”. In recent years, India stands first in the world in terms of its wealth of Palmyra (Borassus flabellifer population nearly 122 million palms. In this study overall purpose was to investigate the utilization of food industry wastes in order for the bioplastic production. To achieve this objective the production of bioplastic from palmyra sprout investigated. In addition, some properties of produced bioplastic such as water, absorption capacity, solubility and biodegradability, characterisation studies were analysed. Journal of University of Shanghai for Science and Technology ISSN: 1007-6735 Volume

Carbon capacity of gray forest soils in the Chechen Republic

Common areas of research needed to measure soil carbon include: (1) the impact of forest management, (2) the impact of climate change, and (3) the impact of increased carbon dioxide. The organic matter of the soil has a great influence on the productivity of the site due to its effect on the physical (bulk density, water retention capacity), biological (microbial populations) and chemical (cation exchange capacity) properties of soils. Recently, there have also been claims of the benefits of dead wood for forest ecosystems. However, as with all nutrients, too much carbon in the soil can have negative consequences, especially with regard to nitrogen immobilization.

Fate of influent microbial populations during medium chain carboxylic acid recovery from brewery and pre-fermented food waste streams

Waste streams continuously introduce active and inactive microbial populations that can influence assembly of microbial communities in chain elongation systems.

A three-dimensional (3D) printing approach to fabricate an isolation chip for high throughput in situ cultivation of environmental microbes

The 3D-printed iChip version made from thermoplastics or photopolymers can isolate microbial populations of a peat swamp in situ with a population profile different from that isolated via the standard in vitro Petri dish cultivation method.

Inter-Cluster Competition and Resource Partitioning May Govern the Ecology of Frankia

Microbes live in a complex communal ecosystem. The structural complexity of microbial community reflects diversity, functionality as well as habitat type. Delineation of ecologically important microbial populations along with exploration of their roles in environmental adaptation or host-microbe interaction has a crucial role in modern microbiology. In this scenario, reverse ecology (the use of genomics to study ecology) plays a pivotal role. Some studies have reported the presence of other non-Frankia genus from the same root nodule from where the Frankia was isolated. Since co-existance of two different genus in one small niche should maintain a strict direct interaction, it will be interesting to utilize the concept of reverse ecology in this scenario.Here, we exploited an ‘R’ package, the RevEcoR, to resolve the issue of co-existing microbes which are proven to be a crucial tool for identifying the nature of their relationship (competition or complementation) persisting among them. Our target organism here is Frankia, a nitrogen-fixing actinobacterium popular for its genetic and host specificity nature. According to their plant host, Frankia has already been subdivided into four clusters CI, CII, CIII and CIV. Our results revealed a strong competing nature of CI Frankia. The competition index between CI and CIII was greater than other studied Frankia clusters. The other interesting result was the co-occurrence of C-II and C-IV groups. It was revealed that these two groups follow the theory of resource partitioning in their lifestyle. Metabolic analysis along with their differential transporter machinery validated our hypothesis of resource partitioning among C-II and C-IV group.

Effects of post-weaning supplementation of immunomodulatory feed ingredient on circulating cytokines and microbial populations in programmed fed beef heifers

The objective was to determine the effects of an immunomodulatory feed ingredient following weaning on cytokine expression and fecal microbial populations of heifers. Commercial Angus heifers (n = 72) were weaned (227 ± 7 d of age), blocked by BW (n = 9 blocks) and randomly assigned to one of 2 pens per block. Pens within weight block (4 heifers/pen) were then randomly assigned to treatments. Heifers were fed twice daily from d 0-60 (to gain 0.75kg/day) and top-dressed with either 18g/heifer/d of the immunomodulatory feed ingredient (Celmanax; Arm and Hammer Animal Nutrition, Princeton, NJ, USA; CEL) or corn-germ meal (CON). Blood samples were collected on d 0, 15, 30, 45, 60 and fecal grab samples on d 0 of the feeding trial. After d 60, two heifers per pen (n=32) were randomly selected for a transportation challenge. Serum samples were collected at h 0, 4, 8, 12 and fecal grab samples at h -24, 0, 24 and 7d post-challenge. Blood samples were analyzed for interferonγ (IFNγ), interleukin-8 (IL-8), and haptoglobin (HP) using commercially available ELISA kits and qRT-PCR for genes of interest associated with cytokine expression. Fecal samples were enumerated for Clostridia and E. coli using selective media (≤ 5 isolates from each media/sample), tested to determine if they were C. perfringens or pathogenic E. coli, and then enriched for detection of Salmonella. Data was analyzed via ANOVA. During the feeding trial, HP was reduced (P = 0.018) in CEL compared to CON at d 15, 45, and 60, while IFNγ and IL-8 did not differ (P > 0.080) between treatments. All cytokines were decreased (P < 0.001) in CEL compared to CON during the challenge. During the feeding trial, HP mRNA was increased (P = 0.045) in CEL compared to CON at d 30 and 60. Similarly, IFNγ mRNA was increased (P = 0.040) in CEL compared to CON, however, other genes of interest did not differ (P > 0.172). Both C. perfringens and total E. coli counts were decreased (P = 0.036) in CEL compared to CON at 24h after the start of the transportation challenge. Clostridia and pathogenic E. coli counts did not differ (P = 0.941) between treatments. Total Clostridia and E. coli counts were increased (P < 0.014) 24h post-challenge. All microbial populations, except pathogenic E. coli, observed decreased (P ≤ 0.009) counts from 24h to 7d post-challenge. Overall, Celmanax supplementation decreased circulating cytokines, and altered microbial populations and gene expression, thus, may serve a role in preparing animals to better cope with immunological challenges.

Phage co-transport with hyphal-riding bacteria fuels bacterial invasion in a water-unsaturated microbial model system

Nonmotile microorganisms often enter new habitats by co-transport with motile microorganisms. Here, we report that also lytic phages can co-transport with hyphal-riding bacteria and facilitate bacterial colonization of a new habitat. This is comparable to the concept of biological invasions in macroecology. In analogy to invasion frameworks in plant and animal ecology, we tailored spatially organized, water-unsaturated model microcosms using hyphae of Pythium ultimum as invasion paths and flagellated soil-bacterium Pseudomonas putida KT2440 as carrier for co-transport of Escherichia virus T4. P. putida KT2440 efficiently dispersed along P. ultimum to new habitats and dispatched T4 phages across air gaps transporting ≈0.6 phages bacteria−1. No T4 displacement along hyphae was observed in the absence of carrier bacteria. If E. coli occupied the new habitat, T4 co-transport fueled the fitness of invading P. putida KT2440, while the absence of phage co-transport led to poor colonization followed by extinction. Our data emphasize the importance of hyphal transport of bacteria and associated phages in regulating fitness and composition of microbial populations in water-unsaturated systems. As such co-transport seems analogous to macroecological invasion processes, hyphosphere systems with motile bacteria and co-transported phages could be useful models for testing hypotheses in invasion ecology.