Determination Of Cell Size Research Articles

Effect of temperature, nutrients and growth rate on picophytoplankton cell size across the Atlantic Ocean.

The cell size of picophytoplankton populations affects their ecology and biogeochemical role, but how different environmental drivers control its variability is still not well understood. To gain insight into the role of temperature and nutrient availability as determinants of picophytoplankton population mean cell size, we carried out five microcosm experiments across the Atlantic Ocean (45°N-27°S) in which surface plankton assemblages were incubated under all combinations of three temperatures (in situ, 3°C cooling and 3°C warming) and two nutrient levels (unamended and addition of nitrogen and phosphorus). The overall range of variability in cell volume was 5-fold for Prochlorococcus, 8-fold for Synechococcus and 6-fold for the picoeukaryotes. We observed, in all the treatments and in the control, a consistent trend toward larger mean cell sizes over time for both Prochlorococcus and Synechococcus, which was likely the result of sample confinement. Changes in temperature and nutrient status alone did not cause clear changes in cell size, relative to the control, but the combination of warming and nutrient addition resulted in an increase in Prochlorococcus and Synechococcus cell size. The largest increases in cell volume were associated with slow or negative population net growth rates. Our results emphasize the importance of considering changes in biovolume to obtain accurate estimates of picophytoplankton biomass and suggest that the inverse relationship between growth rate and population mean cell size may be a general pattern in marine phytoplankton.

High-Throughput Measurement of Single-Fission Yeast Cell Volume Using Fluorescence Exclusion.

Cell volume is a critical parameter for the biology of living species and has an impact on virtually all cellular functions. In Schizosaccharomyces pombe, the regulation of cell size has been the focus of intense investigation, and mechanisms that couple size control with cell cycle progression have been identified. In fission yeast, cell length at division is generally used as a proxy for determining cell size. However, it only allows for an inaccurate evaluation of this critical parameter and neglects potential changes in cell morphology and diameter, which can strongly impact cell volume. Until recently, one of the major obstacles for studying the complexity of cell size regulation in fission yeast has been the lack of a robust method for high-throughput, direct measurement of single-cell volume. Here, we provide a comprehensive protocol for S. pombe cell volume determination based on the Fluorescence eXclusion method and microfluidics technologies. This approach makes it possible to reliably describe cell volume and its distribution in populations of fission yeast cells.

Planctoellipticum variicoloris gen. nov., sp. nov., a novel member of the family Planctomycetaceae isolated from wastewater of the aeration lagoon of a sugar processing plant in Northern Germany

In the present study, we characterise a strain isolated from the wastewater aeration lagoon of a sugar processing plant in Schleswig (Northern Germany) by Heinz Schlesner. As a pioneer in planctomycetal research, he isolated numerous strains belonging to the phylum Planctomycetota from aquatic habitats around the world. Phylogenetic analyses show that strain SH412T belongs to the family Planctomycetaceae and shares with 91.6% the highest 16S rRNA gene sequence similarity with Planctopirus limnophila DSM 3776T. Its genome has a length of 7.3 Mb and a G + C content of 63.6%. Optimal growth of strain SH412T occurs at pH 7.0–7.5 and 28 °C with its pigmentation depending on sunlight exposure. Strain SH412T reproduces by polar asymmetric division (“budding”) and forms ovoid cells. The cell size determination was performed using a semi-automatic pipeline, which we first evaluated with the model species P. limnophila and then applied to strain SH412T. Furthermore, the data acquired during time-lapse analyses suggests a lifestyle switch from flagellated daughter cells to non-flagellated mother cells in the subsequent cycle. Based on our data, we suggest that strain SH412T represents a novel species within a novel genus, for which we propose the name Planctoellipticum variicoloris gen. nov., sp. nov., with strain SH412T (= CECT 30430T = STH00996T, the STH number refers to the Jena Microbial Resource Collection JMRC) as the type strain of the new species.

Apparent simplicity and emergent robustness in the control of the Escherichia coli cell cycle

To examine how bacteria achieve robust cell proliferation across diverse conditions, we developed a method that quantifies 77 cell morphological, cell cycle, and growth phenotypes of a fluorescently labeled Escherichia coli strain and >800 gene deletion derivatives under multiple nutrient conditions. This approach revealed extensive phenotypic plasticity and deviating mutant phenotypes were often nutrient dependent. From this broad phenotypic landscape emerged simple and robust unifying rules (laws) that connect DNA replication initiation, nucleoid segregation, FtsZ ring formation, and cell constriction to specific aspects of cell size (volume, length, or added length) at the population level. Furthermore, completion of cell division followed the initiation of cell constriction after a constant time delay across strains and nutrient conditions, identifying cell constriction as a key control point for cell size determination. Our work provides a population-level description of the governing principles by which E.coli integrates cell cycle processes and growth rate with cell size to achieve its robust proliferative capability. A record of this paper's transparent peer review process is included in the supplemental information.

MYC to BCL6 State-Transitions Determine Cell Size and Metabolic Fluctuations and Define a Novel Biorhythm in B-Cell Malignancies

Background: Cell size fluctuations are well-documented during critical transitions during normal B-cell development. For instance, during early stages of development, “large cycling pre-B cells” (also classified as Fraction C') eventually exit cell cycle and shrink to become “small resting pre-B cells” (Fraction D) to enable immunoglobulin light chain gene recombination. We and others had shown that this transition is marked by loss of Myc expression and gain of Bcl6. Later in development, germinal center B-cells cycle between large MYC+ “centroblast” and smaller BCL6+ “centrocyte” states between dark and light zones, respectively. MYC is involved in biomass accumulation and provides fuel for cell division, while BCL6 confers a quiescent phenotype to cells and protects B cells from DNA damage-induced apoptosis. BCL6 can suppress MYC transcription, indicating MYC and BCL6 is mutually exclusive, and their expression dictates distinct cellular states. Significance: In B-cell malignancies, transitions between mutually exclusive MYC+ and BCL6+ states seem to be important as well: B-ALL cells that are driven by oncogenic tyrosine kinases (e.g. BCR-ABL1) express predominantly MYC but can be forced into a BCL6+ state upon tyrosine kinase inhibition (e.g. imatinib). In germinal center-derived B-cell lymphoma, both MYC and BCL6 are frequently targeted by chromosomal translocation, suggesting that disruption of physiological state transitions may be part of the malignant transformation program. Results: To elucidate regulation of MYC-BCL6 state transitions and their importance in progression and development of drug resistance in B-ALL and germinal center-derived B-cell lymphoma, we developed a MYC-eGFP and BCL6-mCherry dual-reporter mouse model. In addition, we engineered human B-ALL PDX cells with MYC-mNeonGreen and BCL6mScarlet knockin fusion genes by CRISPR/Cas9-mediated HDRT. As expected, MYC+ and BCL6+ states were largely mutually exclusive during early stages of B-cell development, as well as in BCR-ABL1- and NRAS G12D-driven B-ALL. Interestingly, a large fraction of B-ALL cells expressed neither MYC nor BCL6, as validated by cell sorting and Western blot. Based on single-cell sorting and subsequent time-lapse monitoring over 12 hours, we found MYC+ cells transitioning through a double-negative state to become BCL6+ and then revert again to a MYC+ state ( Figure A), suggesting dynamic transitions between MYC and BCL6 cycles. We characterized these populations by analyzing cell size, cell proliferation, cell cycle, clone formation, and gene expression profiles. The results indicated that MYC+ cells exhibited larger cell size, active proliferation, and increased glycolytic activity. Conversely, BCL6+ cells displayed smaller cell size, activation of autophagy with suppression of glycolysis, and cell cycle arrest in the G0 phase of the cell cycle. Conclusions and future directions: Given the dynamic inter-transition between MYC and BCL6 states, and the significant roles of both MYC and BCL6 in B-ALL and germinal center-derived B-cell lymphomas, we propose MYC- and BCL6-dependent fluctuations of cellular activity (wake) and quiescence (sleep; Figure B). Thereby, MYC and BCL6 are expressed in an oscillatory manner. During the MYC state, cells exhibit high glycolysis activity, actively accumulate biomass, and undergo proliferation, representing the wake phase. In contrast, during the BCL6 state, cells suppress glycolysis metabolism, pause the cell cycle, and display a quiescent phenotype, representing the sleep phase. Based on this discovery, we will examine the ‘B-cell exhaustion’ paradigm that Bcl6 and Myc mark iterative cycles of quiescence and activation. In analogy to sleep-wake phases, we hypothesize that the Bcl6-autophagy phase is essential for recovery and regeneration. We will investigate how B-cells transition from one phase to the next and consequences of elongation of one phase at the expense of the other. Malignant B-cells may be particularly sensitive to shortening of quiescence periods (“sleep deprivation”). These and other observations will lead to new conceptual frameworks for the understanding of how MYC-BCL6 state transitions, cell-size fluctuations and the length of recovery-periods regulate energy-supply and survival of B-cell malignancies and create opportunities for therapeutic intervention.

Rheology‐cell structure correlation for foam processing of polypropylene‐titanium dioxide and polypropylene‐graphene nanocomposites

AbstractThis work focuses on understanding the effects of nanoparticle fillers (titanium dioxide (TiO2) and graphene) on foam processing of polypropylene(PP) and makes an attempt to establish a rheology‐cell size correlation for PP‐TiO2 and PP‐graphene nanocomposite foams. The establishment of such a correlation can help develop a precise model to predict optimum nanoparticle concentration in a polymer matrix to produce stable microcellular foams. The effects of adding TiO2 and graphene nanoparticles on nanocomposite properties are studied through their thermal, mechanical, and rheological analysis. The nanocomposite/PP foams are prepared at various conditions, and their morphology and density are studied to obtain an understanding of the cell structure as a function of added nanoparticles. The optimized size/structure has also been correlated in terms of rheological and mechanical properties of the prepared nanocomposites to study the effects of variation in rheological properties on the resultant cell structure of prepared foams. Through the current work it was found that particle type/size plays the dominant factor in determining the cell size of resultant foam, although when comparing foams with varying filler concentration, it was established that a decrease in viscosity and storage modulus would create more cell stability by decreasing the applied stress and would lead to smaller cells.Highlights Rheological property variation can directly affect the polymer foamability Foaming of polymers can be closely simulated using the Maxwell model for polymers Reduction in viscosity leads to smaller and stable cells during foaming Stress relaxation rate determines the cell stabilization during expansion Agglomerate size plays a crucial role in determining cell size

Deep U_ClusterNet: automatic deep clustering based segmentation and robust cell size determination in white blood cell

Deep U_ClusterNet: automatic deep clustering based segmentation and robust cell size determination in white blood cell

Determination of cell size/structures and mechanical properties of additively manufactured metallic components using X-ray technique

PurposeAdditive manufacturing (AM), a rapidly evolving paradigm, has shown significant advantages over traditional subtractive processing routines by allowing for the custom creation of structural components with enhanced performance. Numerous studies have shown that the technical qualities of AM components are profoundly affected by the discovery of novel metastable substructures in diverse alloys. Therefore, the purpose of this study is to determine the effect of cell structure parameters on its mechanical response.Design/methodology/approachInitially, a methodology was suggested for testing porous materials, focusing on static tensile testing. For a qualitative evaluation of the cellular structures produced, computed tomography (CT) was used. Then, the CT scanner was used to analyze a sample and determine its actual relative density, as well as perform a detailed geometric analysis.FindingsThe experimental research demonstrates that the mechanical properties of a cell’s structure are significantly influenced by its shape during formation. It was also determined that using selective laser melting to produce cell structures with a minimum single-cell size of approximately 2 mm would be the most appropriate method.Research limitations/implicationsFurther studies of cellular structures for testing their static tensile strength are planned for the future. The study will be carried out for a larger number of samples, taking into account a wider range of cellular structure parameters. An important step will also be the verification of the results of the static tensile test using numerical analysis for the model obtained by CT scanning.Originality/valueThe fabrication of metallic parts with different cellular structures is very important with a selective laser melted machine. However, the determination of cell size and structure with mechanical properties is quiet novel in this current investigation.

Signaling mechanisms in renal compensatory hypertrophy revealed by multi-omics

Loss of a kidney results in compensatory growth of the remaining kidney, a phenomenon of considerable clinical importance. However, the mechanisms involved are largely unknown. Here, we use a multi-omic approach in a unilateral nephrectomy model in male mice to identify signaling processes associated with renal compensatory hypertrophy, demonstrating that the lipid-activated transcription factor peroxisome proliferator-activated receptor alpha (PPARα) is an important determinant of proximal tubule cell size and is a likely mediator of compensatory proximal tubule hypertrophy.

Systemic changes in cell size throughout the body of Drosophila melanogaster associated with mutations in molecular cell cycle regulators

Along with different life strategies, organisms have evolved dramatic cellular composition differences. Understanding the molecular basis and fitness effects of these differences is key to elucidating the fundamental characteristics of life. TOR/insulin pathways are key regulators of cell size, but whether their activity determines cell size in a systemic or tissue-specific manner awaits exploration. To that end, we measured cells in four tissues in genetically modified Drosophila melanogaster (rictorΔ2 and Mnt1) and corresponding controls. While rictorΔ2 flies lacked the Rictor protein in TOR complex 2, downregulating the functions of this element in TOR/insulin pathways, Mnt1 flies lacked the transcriptional regulator protein Mnt, weakening the suppression of downstream signalling from TOR/insulin pathways. rictorΔ2 flies had smaller epidermal (leg and wing) and ommatidial cells and Mnt1 flies had larger cells in these tissues than the controls. Females had consistently larger cells than males in the three tissue types. In contrast, dorsal longitudinal flight muscle cells (measured only in males) were not altered by mutations. We suggest that mutations in cell cycle control pathways drive the evolution of systemic changes in cell size throughout the body, but additional mechanisms shape the cellular composition of some tissues independent of these mutations.

AKTs do not translocate to the nucleus upon stimulation but AKT3 can constitutively signal from the nuclear envelope.

AKT is a central signaling protein kinase that plays a role in the regulation of cellular survival metabolism and cell growth, as well as in pathologies such as diabetes and cancer. Human AKT consists of three isoforms (AKT1-3) that may fulfill different functions. Here, we report that distinct subcellular localization of the isoforms directly influences their activity and function. AKT1 is localized primarily in the cytoplasm, AKT2 in the nucleus, and AKT3 in the nucleus or nuclear envelope. None of the isoforms actively translocates into the nucleus upon stimulation. Interestingly, AKT3 at the nuclear envelope is constitutively phosphorylated, enabling a constant phosphorylation of TSC2 at this location. Knockdown of AKT3 induces moderate attenuation of cell proliferation of breast cancer cells. We suggest that in addition to the stimulation-induced activation of the lysosomal/cytoplasmic AKT1-TSC2 pathway, a subpopulation of TSC2 is constitutively inactivated by AKT3 at the nuclear envelope of transformed cells.

Cytoskeletal vimentin regulates cell size and autophagy through mTORC1 signaling.

The nutrient-activated mTORC1 (mechanistic target of rapamycin kinase complex 1) signaling pathway determines cell size by controlling mRNA translation, ribosome biogenesis, protein synthesis, and autophagy. Here, we show that vimentin, a cytoskeletal intermediate filament protein that we have known to be important for wound healing and cancer progression, determines cell size through mTORC1 signaling, an effect that is also manifested at the organism level in mice. This vimentin-mediated regulation is manifested at all levels of mTOR downstream target activation and protein synthesis. We found that vimentin maintains normal cell size by supporting mTORC1 translocation and activation by regulating the activity of amino acid sensing Rag GTPase. We also show that vimentin inhibits the autophagic flux in the absence of growth factors and/or critical nutrients, demonstrating growth factor-independent inhibition of autophagy at the level of mTORC1. Our findings establish that vimentin couples cell size and autophagy through modulating Rag GTPase activity of the mTORC1 signaling pathway.

Members of SIAMESE-RELATED Class Inhibitor Proteins of Cyclin-Dependent Kinase Retard G2 Progression and Increase Cell Size in Arabidopsis thaliana.

Cell size requires strict and flexible control as it significantly impacts plant growth and development. Unveiling the molecular mechanism underlying cell size control would provide fundamental insights into plants’ nature as sessile organisms. Recently, a GRAS family transcription factor SCARECROW-LIKE28 (SCL28) was identified as a determinant of cell size in plants; specifically, SCL28 directly induces a subset of SIAMESE-RELATED (SMR) family genes encoding plant-specific inhibitors of cyclin-dependent kinases (i.e., SMR1, SMR2, SMR6, SMR8, SMR9, SMR13, and SMR14), thereby slowing down G2 phase progression to provide the time to increase cell volume. Of the SMR genes regulated by SCL28, genetic analysis has demonstrated that SMR1, SMR2, and SMR13 cooperatively regulate the cell size downstream of SCL28 in roots and leaves, whereas other SMR members’ contribution remains unexplored. This study shows that in root meristematic cells, SMR9 redundantly participates in cell size control with SMR1, SMR2, and SMR13. Moreover, our cell cycle analysis provides the first experimental evidence that SMR proteins inhibit the G2 progression of proliferating cells. Overall, these findings illuminate the diverse yet overlapping roles of SMR proteins in cell cycle regulation while reinforcing that SMRs are essential downstream effectors of SCL28 to modulate G2 progression and cell size.

Supervised machine learning in microfluidic impedance flow cytometry for improved particle size determination.

The assessment of particle and cell size in electrical microfluidic flow cytometers has become common practice. Nevertheless, in flow cytometers with coplanar electrodes accurate determination of particle size is difficult, owing to the inhomogeneous electric field. Pre-defined signal templates and compensation methods have been introduced to correct for this positional dependence, but are cumbersome when dealing with irregular signal shapes. We introduce a simple and accurate post-processing method without the use of pre-defined signal templates and compensation functions using supervised machine learning. We implemented a multiple linear regression model and show an average reduction of the particle diameter variation by 37% with respect to an earlier processing method based on a feature extraction algorithm and compensation function. Furthermore, we demonstrate its application in flow cytometry by determining the size distribution of a population of small (4.6 ± 0.9μm) and large (5.9 ± 0.8μm) yeast cells. The improved performance of this coplanar, two electrode chip enables precise cell size determination in easy to fabricate impedance flow cytometers.

Endocytic trafficking promotes vacuolar enlargements for fast cell expansion rates in plants.

The vacuole has a space-filling function, allowing a particularly rapid plant cell expansion with very little increase in cytosolic content (Löfke et al., 2015; Scheuring et al., 2016; Dünser et al., 2019). Despite its importance for cell size determination in plants, very little is known about the mechanisms that define vacuolar size. Here, we show that the cellular and vacuolar size expansions are coordinated. By developing a pharmacological tool, we enabled the investigation of membrane delivery to the vacuole during cellular expansion. Our data reveal that endocytic membrane sorting from the plasma membrane to the vacuole is enhanced in the course of rapid root cell expansion. While this 'compromise' mechanism may theoretically at first decelerate cell surface enlargements, it fuels vacuolar expansion and, thereby, ensures the coordinated augmentation of vacuolar occupancy in dynamically expanding plant cells.

A hierarchical transcriptional network activates specific CDK inhibitors that regulate G2 to control cell size and number in Arabidopsis

How cell size and number are determined during organ development remains a fundamental question in cell biology. Here, we identified a GRAS family transcription factor, called SCARECROW-LIKE28 (SCL28), with a critical role in determining cell size in Arabidopsis. SCL28 is part of a transcriptional regulatory network downstream of the central MYB3Rs that regulate G2 to M phase cell cycle transition. We show that SCL28 forms a dimer with the AP2-type transcription factor, AtSMOS1, which defines the specificity for promoter binding and directly activates transcription of a specific set of SIAMESE-RELATED (SMR) family genes, encoding plant-specific inhibitors of cyclin-dependent kinases and thus inhibiting cell cycle progression at G2 and promoting the onset of endoreplication. Through this dose-dependent regulation of SMR transcription, SCL28 quantitatively sets the balance between cell size and number without dramatically changing final organ size. We propose that this hierarchical transcriptional network constitutes a cell cycle regulatory mechanism that allows to adjust cell size and number to attain robust organ growth.

1 to 1000 Policy: Controlling Phosphorous Pollution from Tea Farms with Bioretention Cells

When implementing nonpoint source pollution control plans, the size or number of required controlling facilities is a very practical issue. However, quantifying nonpoint source pollution is difficult because it is generated by variable and random rainfall events. This study develops a two-stage optimization process to demonstrate the determination of the optimal bioretention cell size for tea farm pollution control. The optimization process was based on a verified watershed-scale model and a verified site-scale model. The verified watershed model was used to obtain total phosphorous (TP) reduction loads. Once the goal of watershed management was decided, the reduction loads were then allocated and the unit reduction loads were determined. Using the unit reduction loads, the verified tea farm model was used to assess the optimal bioretention cell size for tea farms. A case study using the Jinggualiao stream in the Feitsui Reservoir watershed, Taipei, Taiwan was presented. The results showed that the unit tea farm TP reduction loads were 270 g/ha-year and 326 g/ha-year to reach two water quality goals, and a total of 350 m2 and 600 m2 of bioretention cells were needed, respectively. A 1 to 1000 ratio of the standard bioretention cell area to the tea farm area is recommended as a general control rule.

DELAY OF GERMINATION 1 (DOG1) regulates dormancy in dimorphic seeds of Xanthium strumarium.

Seed dormancy ensures plant survival but many mechanisms remain unclear. A high-throughput RNA-seq analysis investigated the mechanisms involved in the establishment of dormancy in dimorphic seeds of Xanthium strumarium (L.) developing in one single burr. Results showed that DOG1 , the main dormancy gene in Arabidopsis thaliana L., was over-represented in the dormant seed leading to the formation of two seeds with different cell wall properties. Less expression of DME /EMB1649 , UBP26 , EMF2, MOM, SNL2, and AGO4 in the non-dormant seed was observed, which function in the chromatin remodelling of dormancy-associated genes through DNA methylation. However, higher levels of ATXR7 /SDG25, ELF6 , and JMJ16/PKDM7D in the non-dormant seed that act at the level of histone demethylation and activate germination were found. Dramatically lower expression in the splicing factors SUA, PWI , and FY in non-dormant seed may indicate that variation in RNA splicing for ABA sensitivity and transcriptional elongation control of DOG1 is of importance for inducing seed dormancy. Seed size and germination may be influenced by respiratory factors, and alterations in ABA content and auxin distribution and responses. TOR (a serine/threonine-protein kinase) is likely at the centre of a regulatory hub controlling seed metabolism, maturation, and germination. Over-representation of the respiration-associated genes (ACO3 , PEPC3 , and D2HGDH ) was detected in non-dormant seed, suggesting differential energy supplies in the two seeds. Degradation of ABA biosynthesis and/or proper auxin signalling in the large seed may control germinability, and suppression of endoreduplication in the small seed may be a mechanism for cell differentiation and cell size determination.

Photo Phenosizer, a rapid machine learning-based method to measure cell dimensions in fission yeast.

Cell metrics such as area, length, and width provide informative data about cell cycle dynamics. Factors that affect these dimensions include environmental conditions and genotypic differences. Fission yeast ( Schizosaccharomyces pombe ) is a rod-shaped ascomycete fungus in which cell cycle progression is linked to changes in cell length. Microscopy work to obtain these metrics places considerable burdens on time and effort. We now report on Photo Phenosizer (PP), a machine learning-based methodology that measures cell dimensions in fission yeast. It does this in an unbiased, automated manner and streamlines workflow from image acquisition to statistical analysis. Using this new approach, we constructed an efficient and flexible pipeline for experiments involving different growth media (YES and EMM) and treatments (Untreated and MMS) as well as different genotypes ( cut6-621 versus wildtype). This methodology allows for the analysis of larger sample sizes and faster image processing relative to manual segmentation. Our findings suggest that researchers using PP can quickly and efficiently determine cell size differences under various conditions that highlight genetic or environmental disruptions.

PSIII-12 The effect of maternal dietary isoflavone supplementation and infection with porcine reproductive and respiratory syndrome virus on the growth performance of offspring

Abstract The objective of this experiment was to evaluate the effects of maternal infection with porcine reproductive and respiratory syndrome virus (PRRSV) on piglet prenatal development and pre-weaning growth, and the potential for isoflavone supplementation to alleviate these effects. First parity gilts (n = 24) at gestational day (GD) 65 were allotted to one of three treatments: uninfected and fed a diet devoid of isoflavones (CON), infected with PRRSV and fed the control diet (POS), or infected with PRRSV and fed a diet supplemented with 1,500 ppm soy isoflavones (ISF). Gilts were inoculated intranasally with saline or 2.5×104 TCID50/mL of suspended live PRRSV (NADC20 strain) on GD 70. To determine the effects of PRRSV infection in sows, feed intake (GD 70–114) and rectal temperatures (GD 70–91) were recorded daily, while serum TNF-α concentrations were measured weekly. After farrowing (GD 114 ± 2), two piglets closest to the average litter weight were culled either at birth or weaning (21 d of age) to determine body, muscle, and organ weights of offspring pigs. Hematoxylin and eosin staining was performed on left semitendinosus muscles for determination of muscle cell number and size at each time-point. At birth, whole body, muscle, and organ weights were not different (P > 0.22) between groups except that relative liver weight was increased (P < 0.05) in POS compared with CON piglets. At weaning, ISF reduced (P ≤ 0.05) whole body and muscle weights, but greater (P < 0.05) kidney weight compared with CON, and greater (P < 0.05) relative liver weight compared with CON or POS. However, muscle fiber number and size were not different (P > 0.39) between groups at either time-point. These results suggest maternal PRRSV infection altered offspring organ growth, but dietary ISF did not alleviate the detrimental effects of PRRSV infection in sows or offspring.