The performance of current microfluidic methods for exosome detection is constrained by boundary conditions and by fundamental limits to microscale mass transfer and to interfacial exosome binding. Here, we show that a microfluidic chip designed with self-assembled 3D herringbone nanopatterns can detect low levels of tumour-associated exosomes in plasma (10 exosomes μL −1 , or approximately 200 vesicles per 20-μL spiked sample) that would otherwise be undetectable by standard microfluidic systems for biosensing. The nanopatterns promote microscale mass transfer, increase surface area and probe density to enhance the efficiency and speed of exosome binding, and permit drainage of the boundary fluid to reduce near-surface hydrodynamic resistance, thus promoting particle–surface interactions for exosome binding. We used the device for the detection, in 2-μL plasma samples from 20 ovarian cancer patients and from 10 age-matched controls, of exosome subpopulations expressing CD24, EpCAM, and FRalpha proteins, and suggest exosomal FRalpha as a potential biomarker for the early detection and progression monitoring of ovarian cancer. The nanolithography-free nanopatterned device should facilitate the use of liquid biopsies for cancer diagnosis.

BackgroundAlthough modern soybean cultivars feature yellow seed coats, with the only color variation found at the hila, the ancestral condition is black seed coats. Both seed coat and hila coloration are due to the presence of phenylpropanoid pathway derivatives, principally anthocyanins. The genetics of soybean seed coat and hilum coloration were first investigated during the resurgence of genetics during the 1920s, following the rediscovery of Mendel's work. Despite the inclusion of this phenotypic marker into the extensive genetic maps developed for soybean over the last twenty years, the genetic basis behind the phenomenon of brown seed coats (the R locus) has remained undetermined until now.ResultsIn order to identify the gene responsible for the r gene effect (brown hilum or seed coat color), we utilized bulk segregant analysis and identified recombinant lines derived from a population segregating for two phenotypically distinct alleles of the R locus. Fine mapping was accelerated through use of a novel, bioinformatically determined set of Simple Sequence Repeat (SSR) markers which allowed us to delimit the genomic region containing the r gene to less than 200 kbp, despite the use of a mapping population of only 100 F6 lines. Candidate gene analysis identified a loss of function mutation affecting a seed coat-specific expressed R2R3 MYB transcription factor gene (Glyma09g36990) as a strong candidate for the brown hilum phenotype. We observed a near perfect correlation between the mRNA expression levels of the functional R gene candidate and an UDP-glucose:flavonoid 3-O-glucosyltransferase (UF3GT) gene, which is responsible for the final step in anthocyanin biosynthesis. In contrast, when a null allele of Glyma09g36990 is expressed no upregulation of the UF3GT gene was found.ConclusionsWe discovered an allelic series of four loss of function mutations affecting our R locus gene candidate. The presence of any one of these mutations was perfectly correlated with the brown seed coat/hilum phenotype in a broadly distributed survey of soybean cultivars, barring the presence of the epistatic dominant I allele or gray pubescence, both of which can mask the effect of the r allele, resulting in yellow or buff hila. These findings strongly suggest that loss of function for one particular seed coat-expressed R2R3 MYB gene is responsible for the brown seed coat/hilum phenotype in soybean.

SUMMARY The unicellular green alga Chlamydomonas reinhardtii is a biflagellated cell with two actin genes: one encoding a conventional actin (IDA5) and the other encoding a divergent novel actin-like protein (NAP1). Here, we probe how actin redundancy contributes to flagellar assembly. Disrupting a single actin allows complete flagellar assembly. However, when disrupting both actins using latrunculin B (LatB) treatment on the nap1 mutant background, we find that actins are necessary for flagellar growth from newly synthesized limiting flagellar proteins. Under total actin disruption, transmission electron microscopy identified an accumulation of Golgi-adjacent vesicles. We also find that there is a mislocalization of a key transition zone gating and ciliopathy protein, NPHP-4. Our experiments demonstrate that each stage of flagellar biogenesis requires redundant actin function to varying degrees, with an absolute requirement for these actins in transport of Golgi-adjacent vesicles and flagellar incorporation of newly synthesized proteins.

More than two-thirds of all women diagnosed with epithelial ovarian cancer (EOC) will die from the disease (>14,000 deaths annually), a fact that has not changed considerably in the last three decades. Although the 5-year survival rates for most other solid tumors have improved steadily, ovarian cancer remains an exception, making it the deadliest of all gynecologic cancers and five times deadlier than breast cancer. When diagnosed early, treatment is more effective, with a 5-year survival rate of up to 90%. Unfortunately, most cases are not detected until after the cancer has spread, resulting in a dismal 5-year survival rate of less than 30%. Current screening methods for ovarian cancer typically use a combination of a pelvic examination, transvaginal ultrasonography, and serum cancer antigen 125 (CA125), but these have made minimal impact on improving mortality. Thus, there is a compelling unmet need to develop new molecular tools that can be used to diagnose early-stage EOC and/or assist in the clinical management of the disease after a diagnosis, given that more than 220,000 women are living with ovarian cancer in the United States and are at risk of recurrence. Here, we discuss the state of advancing liquid-based approaches for improving the early detection of ovarian cancer.See all articles in this Special Collection Honoring Paul F. Engstrom, MD, Champion of Cancer Prevention

Flagella of the unicellular green alga Chlamydomonas reinhardtii are nearly identical to cilia of mammalian cells and provide an excellent model to study ciliogenesis. These biflagellated cells have two actin genes: one encoding a conventional actin (IDA5) and the other encoding a divergent novel actin-like protein (NAP1). Previously, we described a role for actin in regulation of flagella-building intraflagellar transport machinery and now probe how actin redundancy contributes to this process using a nap1 mutant Chlamydomonas strain. Treatment with Latrunculin B, a potent actin polymerization inhibitor on the nap1 mutant background acutely disrupts all filamentous actins in the cell. We find that actins are an absolute requirement for flagellar growth when the preexisting pool of flagellar precursors is depleted. Nap1 mutants treated with Latrunculin B also showed reduced protein synthesis during regeneration. Finally, loss of functional actins reduced the incorporation of existing flagellar proteins as well as caused mislocalization of a key transition zone gating protein, NPHP-4. These experiments demonstrate that each stage of flagellar biogenesis requires redundant actin function to varying degrees, with an absolute requirement for actin in incorporation of newly synthesized flagellar proteins.

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The interactions between intracellular microbes and their host cells can lead to the discovery of novel drug targets. During Toxoplasma infections, host cells express an array of immunity-related GTPases (IRGs) and guanylate binding proteins (GBPs) that load onto the parasite-containing vacuole to clear the parasite. To counter this mechanism, the parasite secretes effector proteins that traffic to the vacuole to disarm the immunity-related loading proteins and evade the immune response. While the interplay between host IRGs and Toxoplasma effector proteins is well understood, little is known about how Toxoplasma neutralizes the GBP response. We describe here a T. gondii pseudokinase effector, ROP54, that localizes to the vacuole upon invasion and is critical for parasite virulence. Toxoplasma vacuoles lacking ROP54 display an increased loading of the host immune factor GBP2, but not IRGb6, indicating that ROP54 plays a distinct role in immune evasion.

The full potential of vaccines relies on development of effective delivery systems and adjuvants and is critical for development of successful vaccine candidates. We have shown that recombinant vaults engineered to encapsulate microbial epitopes are highly stable structures and are an ideal vaccine vehicle for epitope delivery which does not require the inclusion of an adjuvant. We studied the ability of vaults which were engineered for use as a vaccine containing an immunogenic epitope of C. trachomatis, polymorphic membrane protein G (PmpG), to be internalized into human monocytes and behave as a “natural adjuvant”. We here show that incubation of monocytes with the PmpG-1-vaults activates caspase-1 and stimulates IL-1β secretion through a process requiring the NLRP3 inflammasome and that cathepsin B and Syk are involved in the inflammasome activation. We also observed that the PmpG-1-vaults are internalized through a pathway that is transiently acidic and leads to destabilization of lysosomes. In addition, immunization of mice with PmpG-1-vaults induced PmpG-1 responsive CD4+ cells upon re-stimulation with PmpG peptide in vitro, suggesting that vault vaccines can be engineered for specific adaptive immune responses. We conclude that PmpG-1-vault vaccines can stimulate NLRP3 inflammasomes and induce PmpG-specific T cell responses.