Small Compartments Research Articles

Droplet Interface Bilayers as a Platform for a Spatially Segregated Nanoreactor

Compartmentalisation is a defining feature of biological processes. Within eukaryotic cells, organelles serve as segregated microenvironments for specific biochemical processes. These microenvironments allow distinct chemical environments to be maintained within the cell and concentrate enzymes involved in catalytic cycles in the same space. This concentration of enzymes and substrates within a small segregated environment contributes to the great efficiency of biochemical processes. I aim to investigate the potential of a novel artificial lipid membrane system, the droplet interface bilayer (DIB), as a platform for a spatially segregated compartmentalised nanoreactor. DIB technology serves as a simple method for producing small aqueous compartments bounded by lipid membranes. The incorporation of membrane transport proteins between the aqueous compartments will allow distinct chemical environments to be maintained and for the controlled separation of substrates and products. The nanoreactor design will aim to recreate the segregated microenvironments and enhanced catalytic efficiencies found in biological processes in a synthetic setting.

Compartment Effect on the Prognostic Significance of MRD Detection in CLL: Impact of Treatment Type and Duration of Follow-up

Background: The detection of minimal residual disease (MRD) in CLL using a 0.01% cut-off is an independent predictor of progression-free (PFS) and overall survival (OS) after chemo-immunotherapy. There are several new treatments available and using MRD as a trial endpoint could greatly speed up the identification of the best treatment approaches. MRD assessments can be made in the peripheral blood (PB) or bone marrow (BM) but there is substantial variation in the extent to which different treatments deplete disease in the PB, BM, and nodal compartments.Aims: To compare MRD levels in the PB & BM during/after different treatment approaches to determine differential compartment effects and evaluate the impact on predicting PFS/OS.Methods: The level of residual disease was determined using multi-parameter flow cytometry according to ERIC consensus protocols with a limit of quantification of 10-4 / 0.01% or better; "+" and "-" denotes ≥0.01% and <0.01% MRD respectively. MRD assessment in the CAMFlud and CLL 207 (alemtuzumab-based) trials was performed at end of treatment because cessation was determined by MRD status. In the ADMIRE/ARCTIC (FCR-based) trials, the MRD assessment was 3 months after end of treatment. In the CALiBRe (idelalisib) & IcICLLe (ibrutinib±obinutuzumab) trial, MRD assessments were made during treatment.Results: The MRD level in PB & BM samples taken at the same time, either during or within 6 months of treatment, was available in 556 cases of which 85 (15%) showed discordant results at the 0.01% threshold. The frequency of discrepant PB & BM MRD levels varied across treatment and patient groups (table 1). In 322 evaluable cases from the ADMIRE/ARCTIC trials at 3 months after the end FCR-based therapy, 66/322 were BM+PB-, representing 54% of the total MRD+ cases. Discrepant results with >1 log difference between PB & BM MRD levels were most common in refractory patients treated with alemtuzumab. There were no discrepant results in patients undergoing idelalisib or ibrutinib monotherapy although all patients have ≥0.01% MRD to date. A small compartment effect was apparent in patients treated with a combination of ibrutinib and obinutuzumab but the relative difference in PB vs. BM disease level appears to be approximately half that of rituximab in combination with chemotherapy.To determine whether the discrepant results affect the ability of MRD status to predict outcome, we compared the PFS according to BM & PB MRD status. In the CLL202 (fludarabine + alemtuzumab) trial the PFS for BM+PB- cases was similar to BM+PB+ cases (median PFS was 1.6 and 6.5 months respectively) and both were substantially shorter than for BM-PB- cases (median PFS 44.7 months, Log-rank P<0.001). This contrasts with FCR-based therapy in the ADMIRE/ARCTIC trials where the PFS for BM+PB- cases was most similar to BM-PB- cases and both were substantially longer than for BM+PB+ cases (median PFS >66 months vs. 54 months vs. 33 months for BM-PB- vs. BM+PB- vs. BM+PB+ respectively, Log-rank P<0.001). BM MRD was the most sensitive and informative site for predicting outcome, although MRD status in both PB & BM were strong predictors of PFS and OS. All patients with >1% MRD in the PB also had >1% disease in the BM.Summary/Conclusion: The compartment effect varies greatly according to patient group and treatment. Rituximab typically results in 0.7log lower disease in the PB compared to BM. Patients on BCR-pathway inhibitors have similar levels of disease in PB & BM even in combination with obinutuzumab. This suggests either that BCR-pathway inhibitors counteract the compartment effects of anti-CD20 antibody treatment, or that obinutuzumab is more effective in depleting bone marrow disease than rituximab. Peripheral blood MRD status may be appropriate for predicting outcome in some settings but underestimates MRD level in a substantial proportion of patients. Bone marrow remains the most sensitive and reliable source for MRD detection but is not required if there is >1% MRD in the blood. Evaluating the compartment effect of specific treatment combinations will help to identify approaches to achieve maximal MRD response using peripheral blood monitoring. [Display omitted] DisclosuresRawstron:AbbVie: Honoraria; Roche: Honoraria; Celegene: Honoraria; Janssen: Research Funding; BD Biosciences: Other: Remuneration; Gilead: Consultancy, Honoraria, Research Funding; Genzyme: Honoraria; GlaxoSmithKline: Honoraria. Munir:Alexion pharmaceuticals: Honoraria. Brock:AstraZeneca: Equity Ownership; GlaxoSmithKline: Equity Ownership. Hillmen:Pharmacyclics: Research Funding; Janssen: Honoraria, Research Funding; Roche: Honoraria, Research Funding; Gilead: Honoraria, Research Funding; Abbvie: Research Funding.

The bulk of the hematopoietic stem cell population is dispensable for murine steady-state and stress hematopoiesis

AbstractLong-term repopulating (LT) hematopoietic stem cells (HSCs) are the most undifferentiated cells at the top of the hematopoietic hierarchy. The regulation of HSC pool size and its contribution to hematopoiesis are incompletely understood. We depleted hematopoietic stem and progenitor cells (HSPCs) in adult mice in situ and found that LT-HSCs recovered from initially very low levels (<1%) to below 10% of normal numbers but not more, whereas progenitor cells substantially recovered shortly after depletion. In spite of the persistent and massive reduction of LT-HSCs, steady-state hematopoiesis was unaffected and residual HSCs remained quiescent. Hematopoietic stress, although reported to recruit quiescent HSCs into cycle, was well tolerated by HSPC-depleted mice and did not induce expansion of the small LT-HSC compartment. Only upon 5-fluorouracil treatment was HSPC-depleted bone marrow compromised in reconstituting hematopoiesis, demonstrating that HSCs and early progenitors are crucial to compensate myeloablation. Hence, a contracted HSC compartment cannot recover in situ to its original size, and normal steady-state blood cell generation is sustained with <10% of normal LT-HSC numbers without increased contribution of the few residual cells.

Commercial Dairy Cow Milk microRNAs Resist Digestion under Simulated Gastrointestinal Tract Conditions

Background: MicroRNAs are small, gene-regulatory noncoding RNA species present in large amounts in milk, where they seem to be protected against degradative conditions, presumably because of their association with exosomes.Objective: We monitored the relative stability of commercial dairy cow milk microRNAs during digestion and examined their associations with extracellular vesicles (EVs).Methods: We used a computer-controlled, in vitro, gastrointestinal model TNO intestinal model-1 (TIM-1) and analyzed, by quantitative polymerase chain reaction, the concentration of 2 microRNAs within gastrointestinal tract compartments at different points in time. EVs within TIM-1 digested and nondigested samples were studied by immunoblotting, dynamic light scattering, quantitative polymerase chain reaction, and density measurements.Results: A large quantity of dairy milk Bos taurus microRNA-223 (bta-miR-223) and bta-miR-125b (∼109–1010 copies/300 mL milk) withstood digestion under simulated gastrointestinal tract conditions, with the stomach causing the most important decrease in microRNA amounts. A large quantity of these 2 microRNAs (∼108–109 copies/300 mL milk) was detected in the upper small intestine compartments, which supports their potential bioaccessibility. A protocol optimized for the enrichment of dairy milk exosomes yielded a 100,000 × g pellet fraction that was positive for the exosomal markers tumor susceptibility gene-101 (TSG101), apoptosis-linked gene 2–interacting protein X (ALIX), and heat shock protein 70 (HSP70) and containing bta-miR-223 and bta-miR-125b. This approach, based on successive ultracentrifugation steps, also revealed the existence of ALIX−, HSP70−/low, and TSG101−/low EVs larger than exosomes and 2–6 times more enriched in bta-miR-223 and bta-miR-125b (P < 0.05).Conclusions: Our findings indicate that commercial dairy cow milk contains numerous microRNAs that can resist digestion and are associated mostly with ALIX−, HSP70−/low, and TSG101−/low EVs. Our results support the existence of interspecies transfer of microRNAs mediated by milk consumption and challenge our current view of exosomes as the sole carriers of milk-derived microRNAs.

Goggatomy: A Method for Opening Small Cuticular Compartments in Arthropods for Physiological Experiments.

Most sense organs of arthropods are ensconced in small exoskeletal compartments that hinder direct access to plasma membranes. We have developed a method for exposing live sensory and supporting cells in such structures. The technique uses a viscous light cured resin to embed and support the structure, which is then sliced with a sharp blade. We term the procedure a “goggatomy,” from the Khoisan word for a bug, gogga. To demonstrate the utility of the method we show that it can be used to expose the auditory chordotonal organs in the second antennal segment and the olfactory receptor neurons in the third antennal segment of Drosophila melanogaster, preserving the transduction machinery. The procedure can also be used on other small arthropods, like mosquitoes and mites to expose a variety of cells.

A hybrid continuous-discrete method for stochastic reaction-diffusion processes.

Stochastic fluctuations in reaction–diffusion processes often have substantial effect on spatial and temporal dynamics of signal transductions in complex biological systems. One popular approach for simulating these processes is to divide the system into small spatial compartments assuming that molecules react only within the same compartment and jump between adjacent compartments driven by the diffusion. While the approach is convenient in terms of its implementation, its computational cost may become prohibitive when diffusive jumps occur significantly more frequently than reactions, as in the case of rapid diffusion. Here, we present a hybrid continuous-discrete method in which diffusion is simulated using continuous approximation while reactions are based on the Gillespie algorithm. Specifically, the diffusive jumps are approximated as continuous Gaussian random vectors with time-dependent means and covariances, allowing use of a large time step, even for rapid diffusion. By considering the correlation among diffusive jumps, the approximation is accurate for the second moment of the diffusion process. In addition, a criterion is obtained for identifying the region in which such diffusion approximation is required to enable adaptive calculations for better accuracy. Applications to a linear diffusion system and two nonlinear systems of morphogens demonstrate the effectiveness and benefits of the new hybrid method.

The bulk of the hematopoietic stem cell population is dispensable for murine steady-state and stress hematopoiesis

Long-term repopulating (LT) hematopoietic stem cells (HSCs) are the most undifferentiated cells at the top of the hematopoietic hierarchy. The regulation of HSC pool size and its contribution to hematopoiesis are incompletely understood. We depleted hematopoietic stem and progenitor cells (HSPCs) in adult mice in situ and found that LT-HSCs recovered from initially very low levels (<1%) to below 10% of normal numbers but not more, whereas progenitor cells substantially recovered shortly after depletion. In spite of the persistent and massive reduction of LT-HSCs, steady-state hematopoiesis was unaffected and residual HSCs remained quiescent. Hematopoietic stress, although reported to recruit quiescent HSCs into cycle, was well tolerated by HSPC-depleted mice and did not induce expansion of the small LT-HSC compartment. Only upon 5-fluorouracil treatment was HSPC-depleted bone marrow compromised in reconstituting hematopoiesis, demonstrating that HSCs and early progenitors are crucial to compensate myeloablation. Hence, a contracted HSC compartment cannot recover in situ to its original size, and normal steady-state blood cell generation is sustained with <10% of normal LT-HSC numbers without increased contribution of the few residual cells.

Dendritic diameter influences the rate and magnitude of hippocampal cAMP and PKA transients during β-adrenergic receptor activation

In the hippocampus, cyclic-adenosine monophosphate (cAMP) and cAMP-dependent protein kinase (PKA) form a critical signaling cascade required for long-lasting synaptic plasticity, learning and memory. Plasticity and memory are known to occur following pathway-specific changes in synaptic strength that are thought to result from spatially and temporally coordinated intracellular signaling events. To better understand how cAMP and PKA dynamically operate within the structural complexity of hippocampal neurons, we used live two-photon imaging and genetically-encoded fluorescent biosensors to monitor cAMP levels or PKA activity in CA1 neurons of acute hippocampal slices. Stimulation of β-adrenergic receptors (isoproterenol) or combined activation of adenylyl cyclase (forskolin) and inhibition of phosphodiesterase (IBMX) produced cAMP transients with greater amplitude and rapid on-rates in intermediate and distal dendrites compared to somata and proximal dendrites. In contrast, isoproterenol produced greater PKA activity in somata and proximal dendrites compared to intermediate and distal dendrites, and the on-rate of PKA activity did not differ between compartments. Computational models show that our observed compartmental difference in cAMP can be reproduced by a uniform distribution of PDE4 and a variable density of adenylyl cyclase that scales with compartment size to compensate for changes in surface to volume ratios. However, reproducing our observed compartmental difference in PKA activity required enrichment of protein phosphatase in small compartments; neither reduced PKA subunits nor increased PKA substrates were sufficient. Together, our imaging and computational results show that compartment diameter interacts with rate-limiting components like adenylyl cyclase, phosphodiesterase and protein phosphatase to shape the spatial and temporal components of cAMP and PKA signaling in CA1 neurons and suggests that small neuronal compartments are most sensitive to cAMP signals whereas large neuronal compartments accommodate a greater dynamic range in PKA activity.

Crane system with remote actuation mechanism for use in argon compartment in ACPF hot cell

The Advanced spent fuel Conditioning Process Facility (ACPF) at the Korea Atomic Energy Research Institute (KAERI) has recently been successfully renovated. One of the highlights of this renovation project was the installation of a small argon compartment within the atmospheric hot cell of the facility. Even though a crane system was considered necessary for the remote handling of the processing equipment inside the argon compartment, no suitable commercial cranes were available. This was because a limited amount of space had been reserved for the installation of the crane. Moreover, a master-slave manipulator (MSM), the only available means of maintenance of the crane, was unable to reach it in the limited workspace. To address the difficulties in the design of this crane, in this study, a remote actuation mechanism is devised where the mechanical and electrical parts of the crane system are separated, positioned far away from each other, and connected through power transmission shafts. This approach has two main advantages. First, the electrical parts can be placed inside the workspace of the MSM, hence allowing for remote maintenance. Second, the space occupied by the electrical parts and their cables, which are separate from the crane in the proposed design, can be considered and exploited in designing the mechanical parts of the crane. This enables the construction of a short, special crane in order to maximize the workspace. Furthermore, the mechanical parts for the MSM located outside the workspace are designed to possess a high safety margin to ensure durability. An accurate servo-control system is also developed based on absolute positioning measurement. This allows for the safer performance of perform through automatic operation.

Small Compartment Toxicity

Life experiences, industrial/environmental exposures, and administration of Food and Drug Administration (FDA)-approved drugs may have unintended but detrimental effects on peripheral and central auditory pathways. Most relevant to the readership of this journal is the role that drug treatments approved by the FDA as safe and effective appear to interact with 3 independent modes of toxicity within the small compartment of the ear. What may seem to be trivial drug-induced toxicity has the potential to change important measures of quality of life and functional capacity of mid- to late-life patients. Drugs meant to treat can become the source of interference in the activities of daily living, and as a result, treatment compliance may be jeopardized. Ototoxicity has been defined as the tendency of certain therapeutic agents and other chemical substances to cause functional impairments and cellular degeneration of the tissues of the inner ear resulting in hearing loss. However, one of the largest contributors to hospitalizations is fall-related injuries in the elderly patients associated with disorders of vestibular function linked to progressive and drug-induced toxicities. Tinnitus affects 35 to 50 million adults representing approximately 25% of the US population, with 12 million seeking medical care and 2 to 3 million reporting symptoms that were severely debilitating. This review is intended to highlight these targets of neurotoxicity that threaten the usefulness of drug treatments deemed safe and effective prior to access by the general public.

Atypical calcium regulation of the PKD2-L1 polycystin ion channel.

Native PKD2-L1 channel subunits are present in primary cilia and other restricted cellular spaces. Here we investigate the mechanism for the channel's unusual regulation by external calcium, and rationalize this behavior to its specialized function. We report that the human PKD2-L1 selectivity filter is partially selective to calcium ions (Ca(2+)) moving into the cell, but blocked by high internal Ca(2+)concentrations, a unique feature of this transient receptor potential (TRP) channel family member. Surprisingly, we find that the C-terminal EF-hands and coiled-coil domains do not contribute to PKD2-L1 Ca(2+)-induced potentiation and inactivation. We propose a model in which prolonged channel activity results in calcium accumulation, triggering outward-moving Ca(2+) ions to block PKD2-L1 in a high-affinity interaction with the innermost acidic residue (D523) of the selectivity filter and subsequent long-term channel inactivation. This response rectifies Ca(2+) flow, enabling Ca(2+) to enter but not leave small compartments such as the cilium.

Direct Observation of α-Synuclein Amyloid Aggregates in Endocytic Vesicles of Neuroblastoma Cells.

Aggregation of α-synuclein has been linked to both familial and sporadic Parkinson’s disease. Recent studies suggest that α-synuclein aggregates may spread from cell to cell and raise questions about the propagation of neurodegeneration. While continuous progress has been made characterizing α-synuclein aggregates in vitro, there is a lack of information regarding the structure of these species inside the cells. Here, we use confocal fluorescence microscopy in combination with direct stochastic optical reconstruction microscopy, dSTORM, to investigate α-synuclein uptake when added exogenously to SH-SY5Y neuroblastoma cells, and to probe in situ morphological features of α-synuclein aggregates with near nanometer resolution. We demonstrate that using dSTORM, it is possible to follow noninvasively the uptake of extracellularly added α-synuclein aggregates by the cells. Once the aggregates are internalized, they move through the endosomal pathway and accumulate in lysosomes to be degraded. Our dSTORM data show that α-synuclein aggregates remain assembled after internalization and they are shortened as they move through the endosomal pathway. No further aggregation was observed inside the lysosomes as speculated in the literature, nor in the cytoplasm of the cells. Our study thus highlights the super-resolution capability of dSTORM to follow directly the endocytotic uptake of extracellularly added amyloid aggregates and to probe the morphology of in situ protein aggregates even when they accumulate in small vesicular compartments.

Dairy milk microRNAs resist in vitro digestion in a gastro‐intestinal tract model

MicroRNAs are small, gene regulatory non‐coding RNA species that are present in large amounts in milk where they seem to be protected against degradative conditions, presumably because of their association with exosomes. We monitored the relative stability of commercial dairy milk microRNAs, under the gastrointestinal (GI) tract conditions that prevails during digestion, and examined their association with extracellular vesicles (EVs). To do so, we used a computer‐controlled TNO in vitro GI model (TIM‐1) and analyzed, by quantitative PCR (qPCR), the level of two milk microRNAs within all GI tract compartments at different time points. MicroRNA‐containing EVs within digested and non‐digested samples were studied by immunoblotting, dynamic light scattering, qPCR and density measurements. We observed that an important proportion of dairy milk bta‐miR‐223 and bta‐miR‐125b withstand digestion under simulated GI tract conditions, with the stomach causing the greater loss in microRNAs. A significant amount of these two microRNAs (~108–109 copies/300 ml milk) was detected in the upper small intestine compartments, which supports their bioavailability. A protocol optimized for the enrichment of dairy milk exosomes yielded a 100,000 g pellet fraction positive for the exosomal marker Tumor susceptibility gene‐101 (TSG‐101) and containing bta‐miR‐223 and bta‐miR‐125b. This approach, based on successive ultracentrifugation steps, also revealed the existence of TSG‐101 negative EVs that are larger than exosomes and more enriched in bta‐miR‐223 and bta‐miR‐125b. Our findings indicate that commercial dairy milk contains numerous microRNAs that can resist digestion and are associated mostly with non‐exosomal EVs. Our results strengthen the idea that milk microRNAs are bioactive compounds in dairy milk, support the existence of interspecies transfer of microRNAs based on milk consumption, and challenge our current view of exosomes as the sole carriers of milk‐derived microRNAs.Support or Funding InformationThis work was supported by Grants No. 319618 and 327522 from the Canadian Institutes of Health Research (CIHR), through the Institute of Genetics (to P.P.).

Sensitive red protein calcium indicators for imaging neural activity.

Genetically encoded calcium indicators (GECIs) allow measurement of activity in large populations of neurons and in small neuronal compartments, over times of milliseconds to months. Although GFP-based GECIs are widely used for in vivo neurophysiology, GECIs with red-shifted excitation and emission spectra have advantages for in vivo imaging because of reduced scattering and absorption in tissue, and a consequent reduction in phototoxicity. However, current red GECIs are inferior to the state-of-the-art GFP-based GCaMP6 indicators for detecting and quantifying neural activity. Here we present improved red GECIs based on mRuby (jRCaMP1a, b) and mApple (jRGECO1a), with sensitivity comparable to GCaMP6. We characterized the performance of the new red GECIs in cultured neurons and in mouse, Drosophila, zebrafish and C. elegans in vivo. Red GECIs facilitate deep-tissue imaging, dual-color imaging together with GFP-based reporters, and the use of optogenetics in combination with calcium imaging.

Correlation of visceral adipose tissue measured by Lunar Prodigy dual X-ray absorptiometry with MRI and CT in older men.

Quantification of abdominal visceral adipose tissue (VAT) is important to understand obesity-related comorbidities. We hypothesized that dual X-ray absorptiometry (DXA) measurements of VAT would correlate with traditional gold standards of magnetic resonance imaging (MRI) and computed tomography (CT) in older men. Deming regression and Bland-Altman plots were used to assess the agreement between VAT measured simultaneously by DXA and MRI (n=95) in a cohort of older males participating in a randomized trial of testosterone replacement for diabetes. We also correlated DXA with single-slice CT (n=102) in a cohort of older males undergoing testosterone deprivation for prostate cancer. Lunar Prodigy DXA scanners using enCORE software was used to measure VAT. DXA VAT volume strongly correlated with MRI VAT volume (r=0.90, P<0.0001) and CT VAT area (r=0.83, P<0.0001). As DXA assesses VAT volume in a smaller compartment than MRI, Bland-Altman analysis demonstrated DXA systematically underestimated VAT by an approximately 30% proportional bias. DXA VAT volume measured by Lunar Prodigy DXA scanners correlate well with gold standard MRI and CT quantification methods, and provides a low radiation, efficient, cost-effective option. Future clinical studies examining the effects of interventions on body composition and regional fat distribution may find DXA an appropriate volumetric method to quantify VAT.

The putative ABC transporter encoded by the orf19.4531 plays a role in the sensitivity of Candida albicans cells to azole antifungal drugs.

ATP-binding cassette (ABC) transporters constitute a large superfamily of integral membrane proteins in prokaryotic and eukaryotic cells. In the human fungal pathogen Candida albicans, there are 28 genes encoding ABC transporters and many of them have not been characterized so far. The orf19.4531 (also known as IPF7530) encodes a putative ABC transporter. In this study, we have demonstrated that disruption of orf19.4531 causes C. albicans cells to become tolerant to azoles, but not to polyene antifungals and terbinafine. Therefore, the protein encoded by orf19.4531 is involved in azole sensitivity and we name it as ROA1, the regulator of azole sensitivity 1 gene. Consistently, we show that the expression of ROA1 is responsive to treatment of either fluconazole or ketoconazole inC. albicans In addition, through a GFP tagging approach, Roa1 is localized in a small punctuate compartment adjacent to the vacuolar membrane. However, ROA1 is not essential for the in vitro filamentation of C. albicans cells.

The fertile physics of chemical gardens

Many a child has enjoyed watching the gardens grow; many a physicist has puzzled over the transformation of self-organized, nonequilibrium patterns into permanent structures.

Small-Scale Arc Fault Testing of Medium-Voltage Metal-Enclosed Switchgear

Internal arc fault tests are important for ensuring the safety of medium-voltage metal-enclosed switchgears. Since these tests are conducted at full scale, the costs of the test objects as well as the high-power laboratory are significant. This paper presents an experimental study to clarify whether such tests can be simplified by downscaling. Tests with volume and energy downscaled to 1/3 and 1/10, respectively, were performed on a single-phase arrangement with air as the insulating gas. The test results showed that the internal pressure rise caused by the arc can be reproduced well using a smaller compartment and lower current. The potential damage caused by the exhaust of the hot gas escaping through the pressure-relief openings is more challenging to predict from small-scale tests.

Digital PCR and Applications

Polymerase chain reaction (PCR), is a simple, effective and widely used enzymatic technic especially in the field of molecular biology which provides the opportunity to amplify a specific DNA fragment from DNA complex pool. Several PCR techniques such as realtime PCR, quantitative and qualitative PCR, Reverse Transcriptase PCR, Nested PCR and multiplex PCR have been developed since the first invention of PCR. Due to the various difficulties of the PCR techniques developed so far, widening the application fields and finding out more advanced level of PCR techniques have become the first priority of the researchers. Digital PCR (dPCR) technology has been developed as a new method to permit the evaluation of the small changes in the copy number variations of the rare mutations, differences between the gene expression changes or state of methylation. Digital PCR is a PCR based new technique for the sensitive measurement of number of DNA copies, it provides opportunity to do large number of PCR with a few number of sample dilution and it has so many small compartments where seperate PCRs are executed in each. At the same time, dPCR leaves some of the quantitative methods behind with the performance of determining the quantity of small amount of genetic material within seconds. This method shows high OZET Polimeraz zincir reaksiyonu (PZR), DNA kompleks

Microarrays for the study of compartmentalized microorganisms in alginate microbeads and (W/O/W) double emulsions

Here, we present two array platforms for small (50–100 μm) cell-containing 3D compartments prepared by droplet-based microfluidics.