Agarose Plate Research Articles

Portal protein diversity and phage ecology

Recent whole-genome cyanophage sequencing (Sullivan et al., 2010) has revealed that the sequences of some genes do not match those published previously as single-gene sequences derived from DNA fragments PCR-amplified from phage isolates. Specifically, the g20 gene sequences for S-SSM7 (gene GI:189397276, protein GI:189397277) and Syn33 (gene GI:189397306, protein GI:189397307) in Sullivan and colleagues (2008) were incorrect. The revised sequences do not alter g20 tree topology or the conclusions of Sullivan and colleagues (2008). The source of error for these gene sequences is not certain, but could have its origin in either a clerical error, PCR contamination and/or mixed phage stocks. On this latter point, it has recently come to light that triplicate plaque purifications do not always result in pure stocks for these cyanophages, possibly due to the fluid consistency of the agarose plates (0.28% agarose) required for growth of the host. More reliable purification procedures have subsequently been developed. However, as mixed phage stock preparations could influence host range, we recommend that published host range data (Sullivan et al., 2003) be verified before their use in further research.

Digestive pectinolytic activity in the Sunn pest, Eurygaster integriceps Puton (Hemiptera: Scutelleridae)

Adults of Eurygaster integriceps were collected from the wheat field, dissected and their midguts and salivary glands were removed out. After centrifugation of the homogenates, the resulted supernatants were used as the source of enzyme. Pectinase activity was assayed using agarose plate and colorimetric assays. Pectinesterase and polygalacturonase activity was detected in the first and fourth part of the midgut, respectively. Colorimetric assays revealed more pectinase activity in the first part than the fourth part. No activity was detected in the salivary gland. Optimal pH for pectinase activity in the first part of the midgut was determined at pH set of 3, 4, 5, 6, 7, 8, 9 and 10. The results showed the optimum pH for pectinases occurred at pH 6. Maximum activity for the enzyme incubated at 20,30,35,40, 45, 50, 60, 70, 80, 90 and 100°C for 60 min was observed at 50°C. This is the first report of the presence of pectinases in a scutellerid bug.

Development of an optimized method for the detection of airborne viruses with real-time PCR analysis

BackgroundAirborne viruses remain one of the major public health issues worldwide. Detection and quantification of airborne viruses is essential in order to provide information regarding public health risk assessment.FindingsIn this study, an optimized new, simple, low cost method for sampling of airborne viruses using Low Melting Agarose (LMA) plates and a conventional microbial air sampling device has been developed. The use of LMA plates permits the direct nucleic acids extraction of the captured viruses without the need of any preliminary elution step. Molecular detection and quantification of airborne viruses is performed using real-time quantitative (RT-)PCR (Q(RT-)PCR) technique. The method has been tested using Adenoviruses (AdVs) and Noroviruses (NoVs) GII, as representative DNA and RNA viruses, respectively. Moreover, the method has been tested successfully in outdoor experiments, by detecting and quantifying human adenoviruses (HAdVs) in the airborne environment of a wastewater treatment plant.ConclusionsThe great advantage of LMA is that nucleic acids extraction is performed directly on the LMA plates, while the eluted nucleic acids are totally free of inhibitory substances. Coupled with QPCR the whole procedure can be completed in less than three (3) hours.

Abstract 4775: Role of FoxM1 survival pathway in primary effusion lymphoma cells

Abstract Primary effusion lymphoma (PEL) is associated with Kaposi sarcoma herpesvirus (KSHV) but its pathogenesis is poorly understood. Many KSHV-associated products can deregulate cellular pathways commonly targeted in cancer. The clinical features and natural history of PELs differ greatly from those observed in other lymphomas. The failure to improve outcomes with treatment intensification indicates the need for the introduction of new therapeutic options. Forkhead Box M1 (FoxM1) is a transcription factor that regulates the expression of a number of genes that are involved in cell cycle regulation and metastasis. Over-expression of FoxM1 has been shown in a variety of cancer however its role has not been fully elucidated in PELs. We found that FoxM1 is constitutively expressed in PELs and treatment of PELs with thiostrepton; a specific inhibitor of FoxM1 inhibits cell viability and induces apoptosis in a dose dependent manner. In addition, thiostrepton treatment also efficiently blocks formation of colonies on agarose plates as well as inhibits cell invasion and migration of PEL cell. Thiostrepton treatment causes down-regulation of FoxM1, MMP-2 and MMP-9 in PEL cells leading to activation of the intrinsic apoptotic pathway. Thiostrepton treatment causes conformational changes of Bax protein, leading to loss of mitochondrial membrane potential and release of cytochrome c to the cytosole. This leads to activation of caspase-9, caspase-3, and polyadenosin-5’-diphosphate-ribose polymerase (PARP) cleavage leading to caspase-dependent apoptosis. Altogether, this data demonstrates the possible role of FoxM1 in pathogenesis of PELs and raise the possibility that incorporation of thiostrepton in treatment regimens for primary effusion lymphomas may improve the overall survival of patients suffering from this malignancy. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4775. doi:10.1158/1538-7445.AM2011-4775

A new micro-fluidic channel that provides stable biochemical gradients for cell migration and chemotaxis

Cell migration and chemotaxis play an important role in many physiological and pathological processes. Traditional methods such as agarose plate culture and the transwell chamber model can only detect cell migration induced by a single factor. Microfluidic chips overcome this limitation and further provide multi-parameter conditions and real-time observation. However, microchips are mostly constructed using photolithography, a typically expensive procedure. We introduce an accessible platform made of polydimethylsiloxane, which provides the structure of the microchannel with microwires. These microwires were elongated to form a cross-channel structure with a 500-μm depth. The micro-fluid channel demonstrated a long-lasting concentration gradient that was maintained for up to 2 h, and a pressure gradient that was maintained for up to 3 d. The chemotactic responses of human endothelial cells within the cross- channel were further studied, and the feasibility and applicability of producing this technology were verified.

A Study of Elevated Interleukin-8 (CXCL8) Detection of Leukocyte Migration Inhibitory Activity in Patients Allergic to Beta-Lactam Antibiotics

The leukocyte migration test (LMT) is effective in identifying the causative drug in drug allergies. Both leukocyte migration activating activity (LMAA) and leukocyte migration inhibitory activity (LMIA) are involved in the development of drug allergies. However, no cytokines associated with LMIA have been identified to date. Because CXCL8 played an important role in neutrophil infiltration and activation, we performed the LMT and measured CXCL8 levels in patients with hypersensitivity to beta-lactam antibiotics (beta-lactams) and antipyretic analgesics (APAs) and investigated the pathogenic mechanism of hypersensitivity to these drugs. The LMT was performed according to an improved version of the agarose plate method and CXCL8 levels in the reacted solution that had been stored as described were measured using a solid-phase sandwich enzyme-linked immunosorbent assay. Migration index (MI) values for the LMT were 77.7 ± 11.7 for patients with hypersensitivity to beta-lactams and 83.6 ± 1.9 for those with hypersensitivity to APAs. The CXCL8 concentrations were significantly higher in patients after beta-lactams administration (175.9 ± 71.2 ng/mL) than those without beta-lactams administration (48.3 ± 34.9 ng/mL). The CXCL8 concentrations were significantly lower in patients after APAs administration (41.7 ± 24.3 ng/mL) than those without APAs administration (63.1 ± 30.2 ng/mL). Increased CXCL8 levels produced by beta-lactams administration were accompanied by LMIA. CXCL8 may be involved in LMIA and play a role in beta-lactam allergies. In contrast, the LMIA detected in patients with allergies to APAs may be a cytokine or chemokine other than CXCL8.

Digestive amylase and pectinase activity in the larvae of alfalfa weevil Hypera postica (Coleoptera: Curculionidae)

AbstractThe alfalfa weevil Hypera postica is a serious economic pest in most alfalfa grown in many countries worldwide. Digestive α‐amylase and pectinase activities of larvae were investigated using general substrates. Midgut extracts from larvae showed an optimum activity for α‐amylase against starch at acidic pH (pH 5.0). α‐Amylase from larval midgut was more stable at mildly acidic pH (pH 5–6) than highly acidic and alkaline pH. The enzyme showed its maximum activity at 35°C. α‐Amylase activity was significantly decreased in the presence of Ca2+, Mg2+ and sodium dodecylsulfate. On the contrary, K+ and Na+ did not significantly affect the enzyme activity. Zymogram analysis revealed the presence of one band of α‐amylase activity in in‐gel assays. Pectinase activity was assayed using agarose plate and colorimetric assays. Optimal pH for pectinase activity in the larval midgut was determined to be pH 5.0. Pectinase enzyme is more stable at pH 4.0–7.0 than highly acidic and alkaline pH. However, the enzyme was more stable at slightly acidic pH (pH 6.0) when incubation time increased. Maximum activity for the enzyme incubated at different temperatures was observed to be 40°C. Optimum pH activity for α‐amylase and pectinase is not completely consistent with the pH prevailing in the larval midgut. This is the first report of the presence of pectinase activity in H. postica.

Isolation and Molecular Characterization of a Multicellular Cyanobacterium, Limnothrix/Pseudanabaena sp. Strain ABRG5-3

A cyanobacterium, semi-filamentous multicellular strain ABRG5-3, was isolated and its unique nature was characterized. This axenic strain formed colonies and was motile on an agarose plate. The 16S rRNA gene of ABRG5-3 exhibited similarities to those of the Limnothrix and Pseudanabaena strains, which are known as filamentous and nonheterocystous cyanobacteria. Peaks in absorbance for the accumulation of chlorophyll a, phycocyanin, and phycoerythrin were observed in the cell extract. Natural separation of the pigments occurred in the supernatant of the autolysed cells. The cell lysis was promoted by osmotic shocks and lysozyme treatments. Chlorophyll a and total DNA were abundantly recovered from the cells. Analysis of the restriction-modification system for genomic DNA revealed novel diversity. Moreover, we made a successful attempt to create antibiotic-resistant strains by conjugation with a foreign plasmid, which indicates that strain ABRG5-3 is transformable.

Mechanisms and physiological effects of protamine resistance in Salmonella enterica serovar Typhimurium LT2

Protamines are cationic peptides that exert antimicrobial activity. We have examined the evolution of bacterial resistance to protamine sulphate and the resulting effects on fitness and physiology, with the objective of increasing knowledge about mechanisms of bacterial resistance to antimicrobial peptides. Spontaneous, protamine-resistant Salmonella enterica serovar Typhimurium (i.e. Salmonella Typhimurium) LT2 mutants were isolated on agarose plates containing protamine sulphate. Resistance mutations were identified using transposon insertions and DNA sequencing. Peptide susceptibility was determined by broth dilution tests and antibiotic susceptibility using Etests. Fitness was determined as log-phase growth rates. Growth-compensated strains were isolated by serial passage through population bottlenecks followed by visual screening for large colonies. Protamine-resistant mutants appeared at a rate of 2.3 x 10(-7)/cell/generation. These mutants were 2-20 times more resistant to protamine than the parental strain and less susceptible to several other antimicrobials, including colistin, gentamicin, lactoferricin and human defensin HNP-1. The resistance mutations were mapped to genes involved in haem biosynthesis and respiration, and were associated with a reduction in bacterial fitness. Some mutants could, in the absence of protamine, be evolved to higher fitness by acquiring second-site compensatory mutations. Spontaneous mutants resistant to protamine sulphate were readily selected in Salmonella Typhimurium LT2. These mutants were less susceptible to several other peptides and antibiotics, and had the characteristics of small colony variants, a phenotype often associated with persistent and recurrent infections that are difficult to treat and which could be a strategy for bacteria to escape the killing effects of antimicrobial peptides.

Movement Directionality in Collective Migration of Germ Layer Progenitors

Collective cell migration, the simultaneous movement of multiple cells that are connected by cell-cell adhesion, is ubiquitous in development, tissue repair, and tumor metastasis [1, 2]. It has been hypothesized that the directionality of cell movement during collective migration emerges as a collective property [3, 4]. Here we determine how movement directionality is established in collective mesendoderm migration during zebrafish gastrulation. By interfering with two key features of collective migration, (1) having neighboring cells and (2) adhering to them, we show that individual mesendoderm cells are capable of normal directed migration when moving as single cells but require cell-cell adhesion to participate in coordinated and directed migration when moving as part of a group. We conclude that movement directionality is not a de novo collective property of mesendoderm cells but rather a property of single mesendoderm cells that requires cell-cell adhesion during collective migration.

High-Throughput Quantification of Root Growth Using a Novel Image-Analysis Tool

Measuring the dynamics of plant growth is fundamental to the understanding of plant development processes. This paper describes a high-throughput, automatic method to trace Arabidopsis (Arabidopsis thaliana) seedling roots grown on agarose plates. From the trace, additional software can quantify length, curvature, and stimulus response parameters such as onset of gravitropism. The method combines a particle-filtering algorithm with a graph-based method to trace the center line of a root. This top-down approach is robust to a variety of noise effects and is reasonably flexible across different image sets. The resulting tool requires minimal interaction from the user and is able to process long time-lapse sequences with user interaction only required on the first frame. The tool is described first, followed by its use on two sample data sets, one measuring root length and the other additionally analyzing the gravitropic response and curvature. The tool, RootTrace, is open source; both the program and source code will be available online.

A rapid screening method for bacteria degrading polycyclic aromatic hydrocarbons

A rapid procedure was developed to screen for bacteria that are able to grow on polycyclic aromatic hydrocarbons (PAHs). A drop of ethyl ether-dissolved PAH is spread on a sterilized cellulose acetate/nitrate filter lying on the top of a mineral salts agarose plate. After the evaporation of ethyl ether, a serially diluted sample is spread over the filter and incubated. Subsequently, the PAH degrading bacteria can be counted and isolated. This procedure is a simple method for screening bacterial isolates for the ability to grow with PAHs. This technique is rapid to screen and/or count PAH-degrading bacteria and is also used to streak cultivation without disrupting the PAH layer on plate.

CDNA cloning, expression and fibrin(ogen)olytic activity of two low-molecular weight snake venom metalloproteinases

Two cDNA clones, AplVMP1 and AplVMP2, were isolated from a snake ( Agkistrodon piscivorus leucostoma) venom gland cDNA library. The full-length cDNA sequence of AplVMP1 with a calculated molecular mass of 46.61 kDa is 1233 bp in length. AplVMP1 encodes PI class metalloproteinase with an open reading frame of 411 amino acid residues that includes signal peptide, pro-domain and metalloproteinase domains. The full-length cDNA of the AplVMP2 (1371 bp) has a calculated molecular mass of 51.16 kDa and encodes PII class metalloproteinase. The open reading frame of AplVMP2 with a 457 amino acid residues is composed of signal peptide, pro-domain, metalloproteinase and disintegrin domains. AplVMP1 and AplVMP2 showed 85% and 93% amino acid identical to PI class enzyme Agkistrodon contortrix laticinctus ACLPREF and PII class enzyme Agkistrodon piscivorus piscivorus piscivostatin, respectively. When expressed in Escherichia coli, most of recombinant proteins of AplVMP1 and AplVMP2 were in insoluble inclusion bodies, with soluble yields of 0.7 mg/l and 0.4 mg/l bacterial culture, respectively. Both affinity purified recombinant proteins show proteolytic activity on fibrinogen, although having an activity lower than that of crude A. p. leucostoma venom. Proteolytic activities of AplVMP1 and AplVMP2 were completely abolished after incubation with a final concentration of 100 μM of EDTA or 1,10-phenanthroline. Both AplVMP1 and AplVMP2 were active in a fibrin–agarose plate but devoid of hemorrhagic activity when injected (up to 50 μg) subcutaneously into mice, and had no capacity to inhibit platelet aggregation.

Thrombin like activity of Asclepias curassavica L. latex: Action of cysteine proteases

Aim of the study To validate the scientific basis of plant latex to stop bleeding on fresh cuts. Cysteine protease(s) from Asclepias curassavica (Asclepiadaceae) plant latex was assessed for pro-coagulant and thrombin like activities. Materials and methods A waxy material from the latex of Asclepias curassavica latex was removed by freezing and thawing. The resulted latex enzyme fraction was assayed for proteolytic activity using denatured casein as substrate. Its coagulant activity and thrombin like activity were determined using citrated plasma and pure fibrinogen, respectively. Inhibition studies were performed using specific protease inhibitors to know the type of protease. Results The latex enzyme fraction exhibited strong proteolytic activity when compared to trypsin and exerted pro-coagulant action by reducing plasma clotting time from 195 to 58 s whereas trypsin reduced clotting time marginally from 195 to 155 s. The pro-coagulant activity of this enzyme fraction was exerted by selectively hydrolyzing Aα and Bβ subunits of fibrinogen to form fibrin clot when pure fibrinogen was used as substrate as assessed by fibrinogen–agarose plate method and fibrinogen polymerization assay. Trypsin failed to induce any fibrin clot under similar conditions. The electrophoretic pattern of latex enzyme fraction-induced fibrin clot was very much similar to that of thrombin-induced fibrin clot and mimic thrombin like action. The proteolytic activity including thrombin like activity of Asclepias curassavica latex enzyme fraction was completely inhibited by iodoaceticacid (IAA). Conclusion Cysteine proteases from Asclepias curassavica latex exhibited strong pro-coagulant action and were found to be specific in its action (Thrombin like). This could be the basis for the use of plant latex in pharmacological applications that justify their use as folk medicine.

Significance of salivary adrenomedullin in the maintenance of oral health: Stimulation of oral cell proliferation and antibacterial properties

Adrenomedullin (ADM) promotes epithelial cell proliferation and antimicrobial activity in the gastrointestinal tract. Since ADM is also present in saliva, it was the objective of our study to investigate the role of salivary ADM in the maintenance of oral health. We found mRNA for ADM and the specific receptors CRLR-RAMP2 and CRLR-RAMP3 expressed by the salivary glands and by oral keratinocytes. The hormone was detected in the glandular tissues by western blot, being slightly bigger than the synthetic peptide, indicating a posttranslational modification. ADM was localized using immunohistochemistry and immunofluorescence. Staining specific for ADM was observed near the cell nuclei of the salivary ducts and acini. There was no correlation between ADM from matched saliva and serum of healthy volunteers. The physiological role of salivary ADM in the oral cavity was investigated by incubating buccal keratinocytes with ADM and measurement of the cell proliferation using bromodeoxyuridine (BrDU) assays. There was a significant, dose dependent increase (up to 5-fold; p < 0.001) of the BrDU incorporation after stimulation with ADM (1.5 to 50 ng/mL). The antibacterial properties of salivary ADM was studied by incubation of Gram+ and Gram− bacteria and yeast, isolated from human oral flora, with ADM (0.01–1000 ng/mL) for 24 h. Bacterial growth was inhibited dose dependently ( p < 0.001), whereas the yeast was not affected. This finding was consistent when using radial growth inhibition test on agarose plates as well as photometric measurement in microtiter plates. Our findings suggest an important role of salivary ADM in the maintenance of oral health, being involved as well as in oral cell proliferation and anti-bacterial defense.

薬物アレルギー起因薬検出における白血球遊走試験 (ケモタキシス&amp;middot;チャンバー法)の臨床的有用性の検討

We performed a comparison between leukocyte migration tests performed by the chemotaxis chamber method (LMTchamber) and the agarose plate method (LMT-agarose) to study the usefulness of the LMT-chamber method in the identification of causative drugs in drug allergies.For LMT-agarose,the positive rate among 210 patients suspected of hypersensitivity to drugs (subject patients) was 67.6 % and for the LMT-chamber the positive rate among 197 subject patients was 81.2%,a significantly higher positive rate for the latter (p<0.001,χ2-test).The positive rate for LMT-agarose was 6.9% in 102 patients without hypersensitivity to drugs (control patients) and 9.8% for the LMT-chamber in 82 control patients,but this difference was not significant.In addition,the LMT-chamber produced a higher positive rate than LMT-agarose for all hypersensitivity symptoms and all efficacy categories of the suspected drugs.It also produced a significantly higher positive rate than LMT-agarose in subject patients without addition of self serum (p<0.05,χ2-test) and there were no significant differences between males and females or young and old persons,as there were in the case of LMT-agarose.Our findings indicate that the LMT-chamber may be more sensitive than LMT-agarose in identifying the causative drug in drug allergies and more useful than LMT-agarose for many hypersensitivity symptoms and suspected drugs.In addition,the LMT-chamber is much less influenced than LMT-agarose as regards patient’s own serum,or by sex and age.

Recombinant expression of rt-PA gene (encoding Reteplase) in gametophytes of the seaweed Laminaria japonica (Laminariales, Phaeophyta).

The life cycle of seaweed Laminaria japonica involves a generation alternation between diploid sporophyte and haploid gametophte. The expression of foreign genes in sporophte has been proved. In this research, the recombinant expression in gametophyte was investigated by particle bombardment with the rt-PA gene encoding the recombinant human tissue-type plasminogen activator (Reteplase), which is a thrombolytic agent for acute myocardial infarction (AMI). Transgenic gametophytes were selected by their resistance to herbicide phosphiothricin (PPT), and proliferated in an established bubble column photo-bioreactor. According to the results from quantitative ELISA, Southern blotting, and fibrin agarose plate assay (FAPA) for bioactivity, it was showed that the rt-PA gene had been integrated into the genome of gametophytes of L. japonica, and the expression product showed the expected bioactivity, implying the proper post-transcript modification in haploid gametophyte.

Identification of a serine protease as a major allergen (Per a 10) of Periplaneta americana

Cockroach allergens are associated with the development of asthma, but none of these has been characterized for proteolytic activity. This study was undertaken to isolate and characterize a protease from Periplaneta americana and determine its allergenicity. A serine protease was isolated from P. americana extract using benzamidine sepharose column and characterized by immunobiochemical methods. Allergenicity of the protease was assessed by enzyme-linked immunosorbent assay, immunoblot, intradermal testing, histamine release and peripheral blood mononuclear cells (PBMCs) proliferation. Affinity purified protein of approximately 28 kDa (Per a 10) showed a single band of activity in gelatin zymogram and agarose plate assay. N-terminal sequence (IVGGRPAQI) revealed similarity with mite serine protease allergens and insect trypsins. It demonstrated proteolytic activity with azocollagen > gelatin > defatted-milk > casein including serine protease specific substrate, N-benzoyl-arginine-ethyl-ester-hydrochloride. It was inhibited by serine protease inhibitors, namely aprotinin > pefabloc > AEBSF > PMSF > benzamidine > antipain > leupeptin and trypsin-specific inhibitor (tosyl-lysyl-chloromethyl-ketone) suggesting it to be a trypsin-like serine protease. Per a 10 was recognized as a major allergen, showing IgE reactivity with >80% of cockroach sensitized patients by skin tests and immunoblot. It could induce significant histamine release (P < 0.05) in blood and secretion of interleukin-4 (IL-4) (P < 0.05) and IL-5 (P < 0.05) in culture supernatant of PBMCs from cockroach hypersensitive patients, suggesting a strong allergenic potency. A serine protease isolated from P. americana was demonstrated to be a major allergen (Per a 10). It has a potential for component-based diagnosis of allergy and will be useful in elucidating the mechanism of allergy.

Surface motility of polycyclic aromatic hydrocarbon (PAH)-degrading mycobacteria

Surface motility of the polycyclic aromatic hydrocarbon (PAH)-degrading Mycobacterium gilvum VM552 was tested on agar and agarose plates prepared with varying amounts of gelling agents in the presence and absence of phenanthrene. Extensive spreading, originating from the point of inoculation, was observed on the surfaces of plates prepared with up to 0.3% agar and up to 0.6% agarose. The spreading velocities were 15.8 mm d −1 on 0.3% agar and 19.5 mm d −1 on 0.3% agarose plates. No evidence was found of accelerated or directed surface motility towards PAH crystals. The morphology of spreading M. gilvum VM552 colonies depended on both the carbon source and the type and concentration of the gelling agent. In 0.3% agar plates, M. gilvum VM552 cells were organized in 1–2-mm-wide branches of 1–5 cm length, while on agarose they slid as a homogenous monolayer across the surface. Microscopic inspection of the colonies on agar surfaces suggested that formation of branches was the combined effect of: (i) cell division and growth at the tip of a branch; (ii) propulsion of cells from the mature basal parts of a branch towards the tip; and (iii) physiologically induced reduced friction between cells and agar. Similar surface migration patterns were observed for the anthracene-degrading M. frederiksbergense LB501T.

Transparent Adult Zebrafish as a Tool for In Vivo Transplantation Analysis

The zebrafish is a useful model for understanding normal and cancer stem cells, but analysis has been limited to embryogenesis due to the opacity of the adult fish. To address this, we have created a transparent adult zebrafish in which we transplanted either hematopoietic stem/progenitor cells or tumor cells. In a hematopoiesis radiation recovery assay, transplantation of GFP-labeled marrow cells allowed for striking in vivo visual assessment of engraftment from 2 hr-5 weeks posttransplant. Using FACS analysis, both transparent and wild-type fish had equal engraftment, but this could only be visualized in the transparent recipient. In a tumor engraftment model, transplantation of RAS-melanoma cells allowed for visualization of tumor engraftment, proliferation, and distant metastases in as little as 5 days, which is not seen in wild-type recipients until 3 to 4 weeks. This transparent adult zebrafish serves as the ideal combination of both sensitivity and resolution for in vivo stem cell analyses.