Overlap In Size Distributions Research Articles

A low‐cost and high‐throughput benchtop cell sorter for isolating white blood cells from whole blood

The ability to isolate and purify white blood cells (WBCs) from mixed ensembles such as blood would benefit autologous cell-based therapeutics as well as diagnosis of WBC disorders. Current WBCs isolation methods have the limitations of low purity or requiring complex and expensive equipment. In addition, due to the overlap in size distribution between lymphocytes (i.e., a sub-population of WBCs) and red blood cells (RBCs), it is challenging to achieve isolation of entire WBCs populations. In this work, we developed an inertial microfluidics-based cell sorter, which enables size-based, high-throughput isolation, and enrichment of WBCs from RBC-lysed whole blood. Using the developed inertial microfluidic chip, the sorting resolution is sharpened within 2μm, which achieved separation between 3 and 5μm diameter particles. Thus, with the present cell sorter, a full population of WBCs can be isolated from RBC-lysed blood samples with recovery ratio of 92%, and merely 5% difference in the composition percentage of the three subpopulations of granulocytes, monocytes, and lymphocytes compared to the original sample. Furthermore, our cell sorter is designed to enable broad application of size-based inertial cell sorting by supplying a series of microchips with different sorting cutoff size. This strategy allows us to further enrich the lymphocytes population by twofold using another microchip with a cutoff size between 10 and 15μm. With simplicity and efficiency, our cell sorter provides a powerful platform for isolating and sorting of WBCs and also envisions broad potential sorting applications for other cell types.

Microbubble enhanced acoustic tweezers for size-independent cell sorting

Acoustic tweezers hold great promise for potential applications in cell sorting due to their noncontact, noninvasive, and simple characteristics. Acoustic tweezers, however, have difficulty in separating the cells of the same size distribution, which hampers their applications. In this paper, we demonstrate that assisted by the targeted microbubble, two kinds of cells with an overlap in size distribution can be efficiently separated by surface acoustic waves. By specifically adhering the targeted microbubbles to MDA-MB-231 cells, the acoustic sensitivity of cells can be improved significantly, leading to the isolation of MDA-MB-231 from MCF-7 cells with an efficiency of 91.2 ± 3.4%. This method extends the diversity of acoustic separation and is capable of separation of particles with the same density and diameter, proving a strategy for specific cell sorting.

Separating extracellular vesicles and lipoproteins via acoustofluidics.

Extracellular vesicles (EVs) and lipoproteins are abundant and co-exist in blood. Both have been proven to be valuable as diagnostic biomarkers and for therapeutics. However, EVs and lipoproteins are both on the submicron scale and overlap in size distributions. Conventional methods to separate EVs and lipoproteins are inefficient and time-consuming. Here we present an acoustofluidic-based separation technique that is based on the acoustic property differences of EVs and lipoproteins. By using the acoustofluidic technology, EVs and subgroups of lipoproteins are separated in a label-free, contact-free, and continuous manner. With its ability for simple, rapid, efficient, continuous-flow isolation, our acoustofluidic technology could be a valuable tool for health monitoring, disease diagnosis, and personalized medicine.

The overlapping reproductive traits of the two male mating types of the oval squid Sepioteuthis lessoniana

The oval squid Sepioteuthis lessoniana is polyandrous, and a female mates with several males during a spawning season. This has resulted in two alternative male mating tactics in this species. The larger consort males usually use the male-parallel (MP) mating posture to put spermatophores at the opening of the oviduct; the smaller sneaker males predominantly use the male-upturned (MU) mating posture to place spermatophores around the female’s buccal membrane. Since squid eggs are released from the oviduct, MP mating is expected to have a higher fertilization rate than MU mating. Given the fact that these two male mating tactics are largely dependent on the body size of the male relative to the female, it is unclear how the smaller males are able to reproductively compete with the larger males. On analyzing spermatophore and sperm morphology from populations of adult male squids, spermatophore size was found to be positively correlated with mantle length of these squids, but sperm length was negatively correlated with squid mantle length. More importantly, no distinct size dimorphism exists in relation to either spermatophore morphology or sperm morphology. The overlap in size distributions of the spermatophores and sperms of the male squid thus implies that medium-sized males may have flexible reproductive strategies, switching between MP and MU mating tactics depending on the context of the mating event and/or female choice. This presumed behavioral plasticity might increase the reproductive success of these males and maintain the dynamic stability of two alternative mating types in this polyandrous species.

Role of epibenthic resource opportunities in the parallel evolution of lake whitefish species pairs (Coregonus sp.)

Parallel evolution of a dwarf and normal whitefish has been documented in six post-glacial lakes. Here, we relate the structure and seasonal variations of the epibenthic invertebrate communities to the extent of phenotypic differentiation in these species pairs. The highest phenotypic differentiation occurs in lakes characterized by less overlap in size distribution between limnetic and epibenthic prey which could represent enhanced ecological opportunities for trophic specialization and adaptive divergence. Differences in community assemblages and seasonal variation of biotic and abiotic conditions may also play a role. Accumulating evidence indicates that strong directional selection acting on dwarf whitefish may be more important than divergent selection acting on both sympatric forms in driving whitefish phenotypic divergence and ultimately, ecological speciation. Along with Landry et al. (2007), this study supports the general hypothesis that parallelism in divergence among sympatric dwarf and normal whitefish is associated with parallelism in limnological adaptive landscape.

Size at sex change in protogynous labroids, prey body size distributions, and apex predator densities at NW Hawaiian atolls

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 297:259-271 (2005) - doi:10.3354/meps297259 Size at sex change in protogynous labroids, prey body size distributions, and apex predator densities at NW Hawaiian atolls Edward E. DeMartini1,*, Alan M. Friedlander2, Stephani R. Holzwarth3 1NOAA Fisheries, Pacific Islands Fisheries Science Center, 2570 Dole Street, Honolulu, Hawaii 96822-2396, USA2NOAA, National Ocean Service, National Centers for Coastal Ocean Science - Biogeography Program, and The Oceanic Institute, Makapuu Point/41-202 Kalanianaole Highway, Waimanalo, Hawaii 96795, USA3University of Hawaii, Joint Institute for Marine and Atmospheric Research, 1125B Ala Moana Boulevard, Honolulu, Hawaii 96814, USA *Email: edward.demartini@noaa.gov ABSTRACT: Body sizes at protogynous (sequential, female-to-male) sex change are described for 8 species of labroid fishes (4 labrids, 4 scarids) based on in situ diver observations of the sizes of sex-related color morphs for populations at atolls in the NW Hawaiian Islands. Sizes at sex change are deduced from the median overlap in size distributions of initial phase (IP: female or female and precocious male) and terminal phase (TP) male individuals for each labroid species and from the median sizes of transitional morph individuals of the endemic, spectacled parrotfish Chlorurus perspicillatus. Relative (to maximum) sizes at sex change vary significantly among 4 major species and, within these species, among the 6 reef populations, a finding that contrasts with a recent model of invariant relative size at sex change in protogynous fishes. Overall median size at sex change is compared to the density of a large carangid (giant trevally Caranx ignobilis, the biomass-dominant apex predator) and to that of the respective labroid species population at each atoll. Size at sex change is inversely related to the density of giant trevally but not meaningfully related to the density of the respective labroid population. The size distributions of the labroids—like those of all other prey reef fishes—are strongly skewed toward smaller and larger fish at atolls with higher and lower densities, respectively, of giant trevally. Altogether these observations strongly suggest that higher mortality from predation at greater predator densities, rather than slower growth rates under greater intraspecific competition at higher prey densities, is the cause of the observed differences among atolls in prey attributes. We suggest that prey body size distribution can potentially provide a sensitive measure, complementary to predator density, for assessing changes in the abundance of apex predators on coral reefs. Phenotypic indices of size at sex change from adult female to male in sexually dimorphic labroids with striking differences in coloration (that facilitate underwater observations) have great potential as nondestructive alternatives to gonad examination requiring specimen sacrifice. Labroid color change thus represents a potentially useful index for assessing changes in the functional structure of coral reef fish assemblages and reef ecosystems. KEY WORDS: Apex predation · Population density · Prey body size distribution · Protogynous sex change · Labroids · NW Hawaiian Islands Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 297. Online publication date: August 01, 2005 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2005 Inter-Research.

The diet of two species of Isoperla (Plecoptera: Perlodidae) in relation to season, site, and sympatry

The seasonal change in gut contents of nymphs of Isoperla grammatica and I. difformis from six streams in southern Sweden was analysed. Both species had ingested a variety of benthic prey and vegetable matter, predominantly diatoms. Some seasonality was evident with high percentages of diatoms in spring in I. grammatica, and in autumn in I. difformis. The scope of food was larger in the latter species which contained about equal proportions of vegetable matter, chironomids, mayfly, stonefly, and black fly larvae. In I. grammatica plant matter and chironomids dominated strongly, comprising > 50% of the gut contents on an annual basis, > 90 % in spring. While small nymphs of I. difformis contained a low proportion of animal matter, only gradually increasing with size, the nymphs of I. grammatica were carnivorous from very early instars. Both species switched to a temporarily strong utilization of algae in spring. This differed among sites, and appeared to reflect differences in insolation and thus the availability of algae. There was a significant negative relationship between the mean densities of Isoperla nymphs and the proportion of animal material found in the guts of I. grammatica (R 2 = 0.86). Considering the density of I. grammatica alone, the relationship was weaker (R 2 = 0.56). A positive correlation between predator and prey size was observed. With chironomid prey the size range increased with predator size. With simuliid prey, however, prey size increased with predator size in such a way that it suggests selection rather than just an expanding prey size range. Correlations were stronger and regression coefficients significantly higher for I. grammatica than for I. difformis. We suggest that I. grammatica, which ingests a much wider size range of prey might choose prey of optimal sizes more readily than the more synchronously developing I. difformis. Although the life cycles of the two species are staggered, overlap in size distribution indicates that competition for food could be important in spring. However, observed differences in diet should facilitate coexistence. Gut content differences might in turn be accomplished through microhabitat segregation.

On the Biology of Gnathophylloides Mineri, a Shrimp Inhabiting the Sea Urchin Tripneustes Ventricosus

ABSTRACT The small shrimp Gnathophylloides mineri is a common inhabitant of the short spines of the sea urchin Tripneustes ventricosus found in shallow waters of eastern St. Croix, United States Virgin Islands. It shows remarkable cryptic coloration and behavioral and morphological features suggesting a past history of intense predation pressure. Gnathophylloides mineri feeds on the epithelium covering the sea urchin spines which is abraded by toothed setae on the second maxillipeds and perhaps also by small, handlike structures on the dactyls of the walking legs. It seems likely that dark pigment from the host test is incorporated by the shrimp. Filter feeding also occurs. The shrimp are usually found in groups (up to 13 on a given host) with females greatly outnumbering males. Although there is a broad overlap in size distributions, males are significantly smaller. There is evidence that shrimp move between urchins. Differential male mortality during migration may explain the uneven sex ratio.