Microalgae biomass has garnered significant attention as a renewable energy feedstock and alternative to petroleum-based fuels. The diverse metabolism of green microalgae species additionally ...provides opportunities for recovery of products for feed, food, nutraceutical, cosmetic, and biopharmaceutical industries. Recently, the concept of using microalgae as part of a biorefinery model has been adopted in place of refinery methods focused on recovering one target product. This has led to producers exploring co-production of high value and high volume products in an effort to improve process economics. With numerous potential products and applications, the biomass source or specific strain must be carefully selected to accumulate extractable levels of the target molecule(s). It is additionally imperative to understand the morphology and metabolism of the selected strain to cost-effectively manage all stages of commercial production. This review will focus specifically on microalgae in the division of Chlorophyta, or green algae and their extracellular matrices (ECM), potential for commercial products, and finally describe a holistic approach for biomolecule extraction and recovery. Additionally, cell disruption and fractionation methods for recovery of biomolecules for commercial products are highlighted along with an alternative method, aqueous enzymatic processing for multiple biomolecule extraction and recovery from green microalgae. An emphasis is placed on connecting the morphological characteristics of microalgae ECM or organelle membranes to implications on separation and purification technologies.
Microalgae has potential as a biofuel feedstock and as a source of valuable bioproducts for a variety of food, feed, nutraceutical, and pharmaceutical industries due to high yields of proteins, ...starch, and lipids. However, several challenges are associated with bioproduct extraction from microalgae. The complexity of microalgae cell walls necessitates use of energy intensive disruption methods, but current chemical or mechanical techniques can degrade economically valuable bioproducts. Therefore, disruption methods that target microalgae cell walls are essential, such as enzymatic biomass pretreatment for the release of specific biomolecules. Aqueous enzymatic pretreatment can preserve valuable bioproducts while permitting high levels of cell disruption. In this study, we optimized harvesting times that maximized protein yields in nitrogen depleted cultures and promoted lipid accumulation in the microalgae Chlamydomonas reinhardtii. Furthermore, an aqueous enzymatic assisted extraction (AEAE) treatment was developed. Four lytic enzymes were tested for their ability to permeate C. reinhardtii cell walls. Autolysin treatment was chosen as preferred cell disruption method. Treated cells were visualized by TEM imaging. TEM images and cell counts confirmed cell permeability (100%) and further cell lysis (50%) and product release when cells were treated with autolysin for 24h. Biomass was also subjected to lipid and protein extraction after autolysin treatment and yields were compared to other mechanical and chemical extraction methods. Protein extractability was significantly enhanced by the autolysin pretreatment when compared to sonication pretreatment. Solvent extraction accompanied with autolysin biomass pretreatment significantly enhanced lipid extractable yields as compared to only solvent extraction and solvent plus sonication extraction.
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Background Polypectomy with cold biopsy forceps is a frequently used technique for removal of small, sessile, colorectal polyps. Jumbo forceps may lead to more effective polypectomy because of the ...larger size of the forceps cup. Objective To evaluate the efficiency of cold jumbo biopsy forceps compared with standard forceps for polypectomy of small, sessile, colorectal polyps. Design Randomized, controlled trial. Setting Outpatient endoscopy center. Patients This study involved 140 patients found to have at least one eligible polyp defined as a sessile polyp measuring ≤6 mm. Intervention Polypectomy with cold biopsy forceps. Main Outcome Measurements Complete visual polyp eradication with one forceps bite. Results In 140 patients, a total of 305 eligible polyps were detected (151 removed with jumbo forceps and 154 with standard forceps). Complete visual eradication of the polyp with one forceps bite was achieved in 78.8% of the jumbo forceps group and 50.7% of the standard forceps group ( P < .0001). Biopsies from the polypectomy sites of adenomatous polyps thought to be visually completely eradicated with one bite showed a trend toward a higher complete histologic eradication rate with the jumbo forceps (82.4%) compared with the standard forceps (77.4%), but the difference did not reach statistical significance ( P = .62). The withdrawal time for visual inspection of the colon and time to perform polypectomies were significantly shorter in the jumbo forceps group (mean 21.43 vs 18.23 minutes; P = .02). Limitations Lack of blinding to the type of forceps used. Conclusion The jumbo biopsy forceps is superior to the standard forceps in removing small, sessile polyps. (Clinical trial registration number: NCT00855790 .)
Advances in biochemical and molecular manipulation have led to increased biomass productivity and oil accumulation in the microalgae
C. reinhardtii
. However, scalable processes for the recovery of ...oil and other valuable biomolecules, such as protein, from
C. reinhardtii
are scarce. The use of aqueous enzymatic extraction, a non-solvent and environmentally friendly bioproduct recovery method, provides an opportunity to design an integrated process for oil and protein fractionation to reduce bioenergy and bioproducts costs. Based on the mechanistic understanding of biomolecule distribution and compartmentalization, an aqueous enzymatic treatment for the release of internally stored lipid bodies was designed. Application of a
C. reinhardtii
-produced protease, autolysin, for lysis of the microalgae cell wall was followed by a secondary treatment with trypsin for chloroplast disruption and lipid body release. Protein recovery after the primary treatment with autolysin indicated a 50.1 ± 4.2% release of total soluble protein and localization of lipid bodies still in the chloroplast. The development of a secondary enzyme treatment (trypsin) for chloroplast and lipid body lysis demonstrated a high percent of remaining lipids (73 ± 7%) released into the supernatant. The results indicate that the application of an enzymatic treatment scheme for protein and oil recovery is a promising alternative to traditional extraction processes.
The extraction of surface mined bitumen from oil sands deposits in northern Alberta, Canada produces large quantities of liquid tailings waste, termed oil sands process-affected water (OSPW), which ...are stored in large tailings ponds. OSPW-derived chemicals from several tailings ponds migrating past containment structures and through groundwater systems pose a concern for surface water contamination. The present study investigated the toxicity of groundwater from near-field sites adjacent to a tailings pond with OPSW influence and far-field sites with only natural oil sands bitumen influence. The acute toxicity of unfractionated groundwater and isolated organic fractions was assessed using a suite of aquatic organisms (Pimephales promelas, Oryzias latipes, Daphnia magna, Hyalella azteca, Lampsilis spp., Ceriodaphnia dubia, Hexagenia spp., and Vibrio fischeri). Assessment of unfractionated groundwater demonstrated toxicity towards all invertebrates in at least one far-field sample, with both near-field and far-field samples with bitumen influence toxic towards P. promelas, while no toxicity was observed for O. latipes. When assessing the unfractionated groundwater and isolated organic fractions from near-field and far-field groundwater sites, P. promelas and H. azteca were the most sensitive to organic components, while D. magna and L. cardium were most sensitive to the inorganic components. Groundwater containing appreciable amounts of dissolved organics exhibited similar toxicities to sensitive species regardless of an OSPW or natural bitumen source. The lack of a clear distinction in relative acute toxicities between near-field and far-field samples indicates that the water-soluble chemicals associated with bitumen are acutely toxic to several aquatic organisms. This result, combined with the similarities in chemical profiles between bitumen-influenced groundwater originating from OSPW and/or natural sources, suggests that the industrial bitumen extraction processes corresponding to the tailings pond in this study are not contributing unique toxic substances to groundwater, relative to natural bitumen compounds present in groundwater flow systems.
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•A novel method for extraction and fractionation of dissolved organics was applied to bitumen-influenced groundwater samples•Groundwater with influence from natural bitumen or OSPW chemicals is acutely toxic•Least and most polar organic fractions were toxic, demonstrating multiple chemical classes cause bitumen organic toxicity•Hyalella azteca and Fathead Minnow were most sensitive to bitumen organic mixtures•Freshwater mussels and Daphnia magna were most sensitive to bitumen inorganics
There is an ongoing perception that the pathology job market is poor, which may be discouraging medical students from pursuing the specialty. Academic pathologists believe that jobs are available but ...relocation may be necessary.
To identify trends regarding the geographic relocation of pathologists taking their first job after training.
The College of American Pathologists (CAP) Graduate Medical Education Committee has sent an annual job search survey from 2012-2016 to CAP junior members and fellows in practice for 3 years or less and seeking their first job. Data were analyzed across demographics and geographic domains consisting of the following: stayed at same institution/city, relocated within the same region, or relocated to a different region. Standard statistical methods were used.
Of 501 respondents, 421 reported completing combined anatomic pathology (AP)/clinical pathology (CP) training, while 80 reported AP- or CP-only training. Of the 421 AP/CP respondents, 109 (26%) stayed at the same institution or city, while of the 80 AP- or CP-only respondents, 36 (45%) stayed at the same institution or city. One hundred ninety-nine respondents completed surgical pathology fellowships with 124 (62%) general/oncologic surgical pathology and 75 (38%) subspecialty surgical pathology trainees. Job seekers who completed general surgical pathology/surgical oncologic pathology fellowship accounted for 34 of 52 (65%) of those remaining at the same institution or city, while those with subspecialty training accounted for 40 of 77 (52%) of those relocating to a different region. Relocation did not demonstrate any significant trends in regard to other demographics studied.
The pathology job market appears stable with no precedent for geographic hardship.
Recent insights into human autoimmunity and immune tolerance have come from studies of rare monogenic disorders. For example, type 1 diabetes (T1D) and thyroid autoimmunity are frequent features in ...patients with mutations in AIRE and FOXP3. Dissecting the consequences of these mutations has improved our understanding of the role of central T cell tolerance and T regulatory cells in controlling these organ-specific autoimmune diseases. Over the last decade, rapid advances in genetic sequencing have now allowed for a deeper exploration and discovery of rare variants that are linked to disease with techniques like whole exome sequencing. Using this approach in both kindreds and outlier patients with de novo germline mutations, there has been expanding discovery of mutations in other pathways with a link to organ-specific autoimmunity that include STAT3, STAT1, CTLA4, and LRBA. Here, we utilized a similar approach on a single patient with T1D and other autoimmune and inflammatory conditions. We identified a de novo heterozygous c.457G>A/p.Gly153Arg mutation in the SKAP2 gene. SKAP2 encodes a critical mediator of integrin signaling pathways that regulate myeloid immune cell function. Monocyte-derived macrophages from the individual displayed enhanced activity of integrin pathways and a migratory phenotype in the absence of chemokine stimulation, consistent with SKAP2 p.Gly153Arg being constitutively active. The p.Gly153Arg variant, located in the well-conserved lipid-binding loop, induced similar phenotypes when expressed in a human macrophage cell line. We propose that SKAP2 p.Gly153Arg is a gain-of-function, pathogenic mutation that disrupts myeloid immune cell function, resulting in a break in immune tolerance and T1D. This particular mutation in a patient with T1D and multiple autoimmunity implicates a role for activating SKAP2 variants in autoimmune T1D.
Disclosure
C. Chamberlain: None. N. Rutsch: None. W. Dixon: None. L. R. Letourneau-freiberg: None. L. H. Philipson: Advisory Panel; Self; Nevro Corp., Research Support; Self; Provention Bio, Inc. M. German: Stock/Shareholder; Self; Viacyte, Inc. M. S. Anderson: Consultant; Self; Provention Bio, Inc., VielaBio, Stock/Shareholder; Self; Medtronic, Merck & Co., Inc. C. A. Lowell: None.
Funding
The Leona M. and Harry B. Helmsley Charitable Trust (G-2018PG-T1D018); Larry L. Hillblom Foundation (2014-D-004-NET); University of California San Francisco Parnassus Flow Core (RRID:SCR_018206); National Institutes of Health (P30 DK063720, S101S10OD021822-01); German Research Foundation (ZA428/11-1, ZA428/18-1, INST211/604-1)
An aging population calls for an adequate response in the workforce of medical professionals. The field of pathology has seen a downward trend in numbers of graduating US allopathic medical students ...choosing the specialty. Concerns about the job market after residency and fellowship graduation may be a contributing factor.
To provide an update on the trends emerging from a survey of pathology graduates' job search experience for their first nonfellowship position.
Data from an annual job search survey sent by The College of American Pathologists Graduate Medical Education Committee between 2017 and 2019 to The College of American Pathologists junior members and fellows in practice 3 years or less, actively looking for a nonfellowship position, was analyzed. Various indicators of the job search experience were compared year to year and with the previously published 2012 to 2016 benchmark data.
Analysis revealed positive trends between the 2017 to 2019 data and the 2012 to 2016 benchmark data, including participants' perceiving more ease in finding a position, improved availability of jobs in their subspecialty choice, and higher ratings of satisfaction with the position accepted, as well as a greater proportion of respondents finding a position within 6 months of initiating their job search.
The job market for pathology residents and fellows looking for their first nonfellowship position has improved with respect to multiple indicators, such as ease of finding a position, length of job search, and satisfaction with the position accepted when comparing 2017 to 2019 data with the 2012 to 2016 benchmark data.
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