Variation In Colony Morphology Research Articles

Spatial Distribution and Disease Incidence of Guava Wilt Village Survey Across Prayagraj and Kaushambi, Uttar Pradesh, India

A comprehensive roving survey was conducted in the Prayagraj and Kaushambi districts of Uttar Pradesh, India, both prominent guava-producing regions. The survey, which included 30 villages, revealed widespread guava wilt with incidence rates ranging from 19.04% to 37.93%, averaging 30.19% across the region. Three forms of wilt these are quick, slow, and partial were identified. Kaushambi district had a higher incidence rate (31.56%) compared to Prayagraj district (28.82%). Indarapur village in Kaushambi recorded the highest wilt incidence (37.93%). The survey also found that 66.67% of farmers lacked formal training in guava cultivation, contributing to poor disease management. Guava wilt was most prevalent in older orchards (10+ years) and primarily affected the Allahabad Safeda variety, which had the highest wilt incidence (33.64%). In contrast, the Pant Prabhat variety exhibited the lowest wilt incidence (22.95%). The causal pathogen, Fusarium oxysporum f. sp. psidii, was isolated from diseased plants. Three fungal isolates displayed variations in colony morphology, growth, and sporulation. Microconidia were non-septate and kidney-shaped, while macroconidia were thin- walled and typically 2-3 septate. Two isolates also produced chlamydospores. This study highlights the need for enhanced farmer training and the potential for cultivating wilt-tolerant varieties to mitigate the spread of the disease in the region.

The phase variation between wrinkly and smooth colony phenotype affects the virulence of Vibrio parahaemolyticus.

Vibrio parahaemolyticus, the causative agent of seafood-associated gastroenteritis, undergoes wrinkly and smooth colony switching on the plate. The wrinkly spreader grew faster, had stronger motility and biofilm capacity when compared with the smooth one. However, whether the two phenotypes differ in their virulence still needs to be further investigated. In this study, the data showed that the smooth spreader had stronger virulence phenotypes, including the cytotoxicity against HeLa cells, antibacterial activity against E. coli, adhesive capacity toward HeLa cells, and lethality in zebrafish, relative to the wrinkly one. However, the colony morphology variation had no influence on the haemolytic activity. The mRNA levels of major virulence genes including T3SS1, T6SS1, and T6SS2 were significantly enhanced in the smooth colonies relative to those in the wrinkly colonies. Taken together, the presented work highlighted the different virulence profiles of the wrinkly and smooth colony phenotypes.

Characterization and Antibacterial Activity of Soil Actinomycetes from Diverse Land Use Systems in Meru South, Eastern Kenya

Aim: The increasing emergence and global spread of antibiotic-resistance by microorganisms pose a severe public health threat. Continuous exploration of different environments is required to find new sources of antibacterial compounds. Therefore, the study isolated, characterized and identified potential Actinomycetes candidates with antibacterial activity against bacterial pathogens from diverse land use systems.
 Study Design: Soil samples from land use systems were collected using a cross-sectional survey technique using line transect sampling in order to isolate Actinomycetes. A 30 × 7× 3 factorial experiment with a completely randomized design was used for evaluating Actinomycetes isolates with antibacterial activity.
 Methodology: The in-vitro cultivation of Actinomycetes was evaluated using four selective media. The Actinomycetes isolates were characterized using morphological, biochemical, and molecular markers. The antibacterial activity screening of crude extracts was conducted against six bacterial pathogens using the agar well diffusion method. The antibacterial activity of Actinomycetes isolates were analyzed using Analysis of Variance. The molecular identification was performed using 16S rRNA sequence homology.
 Results: The morphological analysis showed variations in colony morphology, including differences in color, size, and texture. Biochemical tests provided insights into the metabolic capabilities of the isolates, indicating variations in enzymatic activities and substrate utilization. Antagonistic activity of Actinomycetes extracts exhibited significant differences (P =.05) against test bacterial pathogens. Notably, isolate C52 from degraded forest zone showed the highest antibacterial activity against Staphylococcus aureus (12.21 mm), isolate L6 (16.23 mm) against Listeria monocytogenes and isolate C50 (15.5 mm) against Raoutella planticola. Streptomyces celluloflavus, S. griseobrunneus, S. pratensis, S. crystallinus, and S. eurocidicus were identified in the study.
 Conclusion: The crude extracts obtained from Actinomycetes showed significant antibacterial activity against the selected test organisms. This suggests the presence of bioactive compounds with potential antibacterial properties within these extracts.

Effect of light-mediated variations of colony morphology on the buoyancy regulation of Microcystis colonies

Light is an important driver of algal growth and for the formation of surface blooms. Long-term buoyancy maintenance of Microcystis colonies is crucial for their aggregation at the water surface and the following algal bloom development. However, the effect of light-mediated variations of colony morphology on the buoyancy regulation of Microcystis colonies remains unclear. In this study, growth parameters, colony morphology and floatation/sinking performance of Microcystis colonies were determined to explore how variations in colony morphology influence the buoyancy of colonies under different light conditions. We quantified colony compactness through the cell volume to colony volume ratio (VR) and found different responses of colony size and VR under different light intensities. Microcystis colonies with higher VR could stay longer at the water surface under low light conditions, which was beneficial for the long-term growth and buoyancy maintenance. However, increased colony size and decreased compactness were observed at a later growth stage under relatively higher light intensity (i.e., >108 µmol photons m−2 s−1). Interestingly, we found a counterintuitive negative correlation between colony size and buoyancy of Microcystis under high light intensity. Additionally, we found that the influence of colony morphology on buoyancy was stronger at high light intensity. These results indicate that light could regulate the buoyancy via colonial morphology and that the role of colony morphology in buoyancy regulation needs to be accounted for in further studies under variable environmental conditions.

AphA directly activates the transcription of polysaccharide biosynthesis gene scvE in Vibrio parahaemolyticus

Vibrio parahaemolyticus, a seafood-borne pathogen, is capable of forming biofilms on surfaces. Exopolysaccharide (EPS) plays crucial roles in holding bacterial cells together and keeping biofilm attached on the surface. The cpsA-K and scvA-O gene clusters are responsible for EPS synthesis in V. parahaemolyticus. AphA, the master quorum sensing (QS) regulator operating at low cell density (LCD), positively regulates transcription of cpsA-K and scvA-O, but lacks the detailed mechanisms. The present data showed that the aphA mutant produced smooth colonies, whereas the wild-type strain produced wrinkled colonies. AphA bound the regulatory DNA region of scvE to activate its transcription, whereas it positively regulated transcription of cpsA and scvA in an indirect manner. The transcriptional level of scvE gradually decreased with increasing cell density, which correlated with the expression level of aphA. Taken together, this work elucidated how AphA regulated the biofilm-associated colony morphology variation in V. parahaemolyticus through its regulatory actions on the expression of EPS genes.

Abstract 3856: Elucidating the role of fibroblasts in CRPC and ADPC progression using 3D engineered prostate cancer tissues

Abstract Prostate cancer (PC) currently represents 7.5% of all new cancer cases; notably, the 5-year relative survival rate drops from 100% in localized cases to 30.2% in patients who present with metastases. There are no curative therapies for metastatic PC, and most men develop serial resistance to androgen suppression, resulting in a more aggressive disease state that is much more difficult to mitigate. Fibroblasts have been implicated in cancer progression and are thought to intravasate alongside circulating tumor cells and prime metastatic sites for tumor growth. Our understanding of the precise mechanisms by which they contribute to PC, however, is relatively underdeveloped in comparison to other solid cancer types. Here, we report a three-dimensional (3D) engineered prostate cancer tissue (EPCaT) model comprised of PC-3 castration-resistant (CRPC) or LNCaP androgen-dependent (ADPC) PC cell lines in direct coculture with BJ-5ta fibroblasts. By specifically isolating this cell-cell interaction within a bioinspired poly(ethylene glycol)-fibrinogen (PF) matrix, our EPCaT model introduces the ability to monitor coculture-driven changes at a tissue, cellular, and transcriptomic level. Temporal variations in EPCaT growth, cell and colony morphology, cell populations, and cell-mediated remodeling of the PF matrix were assessed. Changes in bulk transcriptomic expression were also quantified and differentially expressed genes (DEGs) were evaluated between CRPC and ADPC mono- and coculture conditions. Finally, to evaluate the clinical significance of our findings, EPCaTs were evaluated against normal and primary tumor tissue transcriptomic data acquired from the Cancer Genome Atlas (TCGA). In comparison to monoculture EPCaTs, both CRPC- and ADPC-fibroblast coculture conditions resulted in an increase in the number of proliferative cells, morphological features of cancer cell migration, and cell-mediated remodeling of the PF matrix, all of which suggest a more aggressive cell phenotype. DEG and gene ontology analysis revealed coculture-driven changes in genes associated with important tumorigenic processes including ECM organization, angiogenesis, and epithelial cell proliferation and migration. Interestingly, fibroblast coculture had a significantly larger impact on the ADPC transcriptome in comparison to CRPC, suggesting that fibroblasts could play an elevated role in less aggressive disease states. Notable DEGs in ADPC coculture that were also clinically significant in the TCGA tumor versus normal comparison included an overexpression of OR51E2 which has been shown to increase epithelial cell proliferation and participate in the ADPC to CRPC switch, thus exacerbating PC progression. Future studies will augment the pathophysiological relevance of our EPCaT model by including patient-isolated cancer-associated fibroblasts from recurring and non-recurring patients. Citation Format: Nicole L. Habbit, Benjamin Anbiah, Joshita Suresh, Yuan Tian, Luke S. Anderson, Megan L. Davies, Iman Hassani, Taraswi Mitra Ghosh, Balabhaskar Prabhakarpandian, Robert D. Arnold, Elizabeth A. Lipke. Elucidating the role of fibroblasts in CRPC and ADPC progression using 3D engineered prostate cancer tissues [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3856.

Phylogenetic analyses and cross‐infection studies of Phytophthora species infecting cacao and durian in South‐Central Mindanao, Philippines

AbstractPhytophthora pathogens have contributed largely to the production losses of plantation crops such as cacao and durian. Correct identification and knowledge of the diversity of the pathogen is a requisite in the formulation of effective management strategies. Fifty‐eight putative Phytophthora isolates were collected from cacao and durian orchards in South‐Central Mindanao, Philippines, with 43 from cacao and 15 from durian. Molecular identification of isolates based on DNA sequences of the internal transcribed spacer (ITS), partial β‐tubulin (β‐tub) and mitochondrial gene (cox2+spacer) regions combined with morphocultural characterization identified 57 Phytophthora palmivora isolates from cacao and durian typically showing variations in colony morphology and sporangial shape. However, these variations were not phylogenetically informative. One Phytophthora meadii (CDDS‐P3) causing pod rot of cacao was phylogenetically isolated from P. palmivora. Phylogenetic analysis of isolates using combined ITS, β‐tubulin (β‐tub) and mitochondrial (cox2+spacer) DNA regions showed an intraspecific variation within P. palmivora. Representative isolates of P. palmivora used for cross‐inoculation showed more aggressiveness on its original host with higher lesion diameter and less aggressiveness on its potential hosts with smaller lesion diameter on artificially inoculated detached plant part. All Phytophthora isolates were tested pathogenic to cacao, durian and its potential hosts (rubber and coconut); therefore, cross‐infection in the field is possible in an intercrop system. Implementation of combined control strategies should be done against highly diverse pathogens such as P. palmivora and the potentially destructive pathogen P. meadii, which was tested pathogenic and virulent to its original (cacao) and potential hosts (coconut, durian and rubber).

Viability and Colony Morphology Variation of Rhodococcus rhodochrous CNMN-Ac-05 in the Presence of Magnetite Nanoparticles

In recent decades the use of nanotechnologies in the remediation of xenobiotic substances has proven its effectiveness, but not its safety. Nanoparticles often accumulate in the remedied environment, having, over time, toxic effects on living organisms. In this context, research on the vital activity of microorganisms and their interaction with nanoparticles is of major importance. Aim of the research was to determine the influence of Fe3O4 nanoparticles, obtained by different ways (laboratory method and synthesis in the reactor) on the viability and colony morphology of Rhodococcus rhodochrous CNMN-Ac-05 strain. Methods. Encapsulated magnetite (Fe3O4) nanoparticles were synthesized by chemical co-precipitation method, using iron(II) sulfate and iron(III) chloride in the presence of poly-N-vinylpyrrolidone, used as a stabilizer. Fe3O4 SR (Synthesis in the Reactor) was produced in the multifunctional reactor VGR-50, at the same conditions. Cell biomass was determined on the spectrophotometer by the optical density at 540 nm,with subsequent recalculation to cell dry weight according to the calibration curve. The cell dry weight was determined by gravimetric method. The morphological features of the rhodococci colonies were described according to the standard microbiological method. Results. It was established that magnetite nanoparticles in concentrations of 1–100 mg/L were not toxic to the R. rhodochrous strain, had a positive effect on the viability of rhodococci by stimulating the growth of biomass, regardless of their concentration and the method of their synthesis. In the presence of Fe3O4 nanoparticles the population dissociated to S1, S2, R1, R2 forms, and S-R type of colonies, while the basic morphological features of R. rhodochrous colonies corresponded to type S1. Conclusions. The optimal concentration of magnetite nanoparticles, which stimulated the growth and development of R. rhodochrous was 25 mg/L for Fe3O4 and 50 mg/L Fe3O4 SR. At all concentration of Fe3O4 nanoparticles the main colony morphotype of the rhodococci was smooth S1-type; the new types of colonies represented only 0.1–0.6% of the population, and the lowest degree of variability corresponded with the highest colony-forming units index.

Video bioinformatics analysis of human pluripotent stem cell morphology, quality, and cellular dynamics.

StemCellQC is a video bioinformatics software tool for the quantitative analysis of human pluripotent stem cell (hPSC) colonies. Our objective was to use StemCellQC to evaluate and compare various experimental culture conditions, cell lines, and treatments and to demonstrate its applicability to PSC problems. Seven key features were identified that provided useful information on PSC morphology, dynamic behavior, and viability. Colony attachment was better on laminin‐521 than on Matrigel and Geltrex. Growth rates were similar on each matrix when data were normalized. The brightness/area ratio feature showed greater cell death in colonies grown on Matrigel and Geltrex than on laminin‐521 further contributing to an overall greater yield of cells on laminin‐521. Four different PSC culture media performed similarly; however, one medium produced batch‐to‐batch variation in colony morphology and dynamic features. Two embryonic and one induced pluripotent stem cell line showed significant differences in morphology, growth rates, motility, and death rates. Cells from the same vial that became phenotypically different in culture showed measurable differences in morphology, brightness, and motility. Likewise, differentiating and undifferentiated colonies varied in growth rate, intensity, and motility. Three pluripotent cell lines treated with a low concentration of cinnamaldehyde, a chemical used in consumer products, showed adverse effects and differed in their sensitivity to treatment. Our data demonstrate various applications of StemCellQC which could be used in basic and translational research, toxicological and drug testing, and clinical facilities engaged in stem cell therapy.

Recent trends in disease occurrence in the non-traditional rubber-growing areas of Sri Lanka

As the rubber industry is being extended to non-traditional areas in Uva, Northern and Eastern provinces in Sri Lanka, it was important to extend the crop protection arm to those areas also. The disease profile recorded in those areas for a period of three years was studied. The symptomatology of the major diseases and the diversity of the Sri Lankan populations of the pathogens causing major diseases were also studied. Furthermore, the alternative hosts of the pathogens of the major diseases were also looked for. With the observations made, it could be concluded that, during the study period, brown root disease was the malady with the highest incidence in the non-traditional rubber-growing areas of Sri Lanka. Encrustation of sand and stones on the root surface could be identified as the characteristic diagnostic symptom of the disease. The different isolates of Phellinus noxius showed variations in colony morphology. With the contextual observations of the reported incidences, drier soil conditions, poor land preparation and association with the forest-associated tree species were suggested to be the major reasons for the higher incidence of brown root disease in the studied areas. White root disease was also recorded to a lesser extent. Corynespora leaf fall disease was found to be the foliar disease with the highest incidence. Cow pea (Vigna unguiculata) and soy bean (Glycine max) were recorded to be two alternative hosts of Corynespora-causing fungus.

Progenitor cells from different zones of human cartilage and their correlation with histopathological osteoarthritis progression.

Cell-based therapies development for the treatment of osteoarthritis (OA) requires an understanding of the disease progression and attributes of the cells resident in cartilage. This study focused on quantitative assessment of the concentration and biological potential of stem and progenitor cells resident in different zones of cartilage displaying macroscopic Outerbridge grade 1-2 OA, and their correlation with OA progression based on established histologic scoring system. Lateral femoral condyles were collected from 15 patients with idiopathic OA and varus knees undergoing total knee arthroplasty. Superficial(Csp , top ∼ 500 µm) and deep cartilage(Cdp ) was separated. Chondrogenic Connective Tissue Progenitors (CTP-C) were assayed by standardized Colony-Forming-Unit assay using automated image analysis (ColonyzeTM ) based on ASTM standard F-2944-12. Cell concentration (cells/mg) was significantly greater in Csp (median: 7,000; range: 3,440-17,600) than Cdp (median: 5,340; range: 3,393-9,660), p = 0.039. Prevalence (CTPs/million cells) was not different between Csp (median: 1,274; range: 0-3,898) and Cdp (median:1,365; range:0-6,330), p = 0.42. In vitro performance of CTP-C progeny varied widely within and between patients, manifest by variation in colony size and morphology. Mean histopathological Mankin score was 4.7 (SD = 1.2), representing mild to moderate OA. Tidemark breach by blood vessels was associated with lower Csp cell concentration (p = 0.02). Matrix degradation was associated with lower Cdp cell and CTP-C concentration (p = 0.015 and p = 0.095, respectively), independent of articular surface changes. These findings suggest that the initiation of OA may occur in either superficial or deep zones. The pathological changes affect CTP-Cs in Csp and Cdp cartilage zones differently. The heterogeneity among the available CTP-Cs in Csp and Cdp suggests performance-based selection to optimize cell-sourcing strategies for therapy. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1728-1738, 2018.

Identification and characterization of a locus putatively involved in colanic acid biosynthesis in Vibrio alginolyticus ZJ-51

Colanic acid (CA) is a group I extracellular polysaccharide (EPS) that contributes to resistance against adverse environments in many members of the Enterobacteriaceae. In the present study, a genetic locus EPSC putatively involved in CA biosynthesis was identified in Vibrio alginolyticus ZJ-51, which undergoes colony morphology variation between translucent/smooth (ZJ-T) and opaque/rugose (ZJ-O). EPSC in ZJ-T carries 21 ORFs and resembles the CA cluster of Escherichia coli K-12. The deletion of EPSC led to decreased EPS and biofilm formation in both genetic backgrounds but no alternation of lipopolysaccharide. The loss of this locus also changed the colony morphology of ZJ-O on the 2216E plate and reduced the motility of ZJ-T. Compared with ZJ-T, ZJ-O lacks a 10-kb fragment (epsT) in EPSC containing homologs of wecA, wzx and wzy that are essential for O-antigen synthesis. However, the deletion or overexpression of epsT resulted in no change of colony morphology, biofilm formation or EPS production. This study reported at the first time a genetic locus EPSC that may be involved in colanic acid synthesis in V. alginolyticus ZJ-51, and found that it was related to EPS biosynthesis, biofilm formation, colony morphology and motility, which may shed light on the environmental adaptation of the vibrios.

Aetiology of anthracnose on grapevine shoots in Brazil

Anthracnose is an important disease in vineyards in south and southeast Brazil, the main grape‐producing regions in the country. This study aimed to identify the causal agents of grapevine anthracnose in Brazil through multilocus phylogenetic analyses, morphological characterization and pathogenicity tests. Thirty‐nine Elsinoë ampelina and 13 Colletotrichum spp. isolates were obtained from leaves, stems and berries with anthracnose symptoms collected in 38 vineyards in southern and southeastern Brazil. For E. ampelina isolates, the internal transcribed spacer (ITS), histone H3 (HIS3) and elongation factor 1‐α (TEF) sequences were analysed. HIS3 was the most informative region with 55 polymorphic sites including deletions and substitutions of bases, enabling the grouping of isolates into five haplotypes. Colonies of E. ampelina showed slow growth, variable colouration and a wrinkled texture on potato dextrose agar. Conidia were cylindrical to oblong with rounded ends, hyaline, aseptate, (3.57–) 5.64 (−6.95) μm long and (2.03–) 2.65 (−3.40) μm wide. Seven species of Colletotrichum were identified: C. siamense, C. gloeosporioides, C. fructicola, C. viniferum, C. nymphaeae, C. truncatum and C. cliviae, with a wide variation in colony and conidium morphology. Only E. ampelina caused anthracnose symptoms on leaves, tendrils and stems of Vitis vinifera and V. labrusca. High disease severity and a negative correlation between disease severity and shoot dry weight were observed only when relative humidity was above 95%. In this study, only E. ampelina caused anthracnose symptoms on grapevine shoots in Brazil.

Pseudomonas aeruginosa variants obtained from veterinary clinical samples reveal a role for cyclic di-GMP in biofilm formation and colony morphology.

Overuse of antibiotics is contributing to an emerging antimicrobial resistance crisis. To better understand how bacteria adapt tolerance and resist antibiotic treatment, Pseudomonas aeruginosa isolates obtained from infection sites sampled from companion animals were collected and evaluated for phenotypic differences. Selected pairs of clonal isolates were obtained from individual infection samples and were assessed for antibiotic susceptibility, cyclic di-GMP levels, biofilm production, motility and genetic-relatedness. A total of 18 samples from equine, feline and canine origin were characterized. A sample from canine otitis media produced a phenotypically heterogeneous pair of P. aeruginosa isolates, 42121A and 42121B, which during growth on culture medium respectively exhibited hyper dye-binding small colony morphology and wild-type phenotypes. Antibiotic susceptibility to gentamicin and ciprofloxacin also differed between this pair of clonal isolates. Sequence analysis of gyrA, a gene known to be involved in ciprofloxacin resistance, indicated that 42121A and 42121B both contained mutations that confer ciprofloxacin resistance, but this did not explain the differences in ciprofloxacin resistance that were observed. Cyclic di-GMP levels also varied between this pair of isolates and were shown to contribute to the observed colony morphology variation and ability to form a biofilm. Our results demonstrate the role of cyclic di-GMP in generating the observed morphological phenotypes that are known to contribute to biofilm-mediated antibiotic tolerance. The generation of phenotypic diversity may go unnoticed during standard diagnostic evaluation, which potentially impacts the therapeutic strategy chosen to treat the corresponding infection and may contribute to the spread of antibiotic resistance.

Observation of Pneumococcal Phase Variation in Colony Morphology.

Streptococcus pneumoniae (pneumococcus) is an important human pathogen that causes pneumonia, meningitis, sepsis, and otitis media. This bacterium normally resides in the nasopharynx as a commensal, but sometimes disseminates to sterile sites of humans and causes local or systemic inflammation. This biphasic behavior of S. pneumoniae is correlated with a reversible switch between the opaque and transparent colony forms on agar plates, a phenomenon referred to as phase variation. The opaque variants appear to be more virulent in animal models of bacteremia but are deficient in nasopharyngeal colonization animal models. In contrast, the transparent variants display higher levels of nasopharyngeal colonization but relatively lower virulence in animal models. We have recently demonstrated that pneumococcal phase variation between these two colony types is caused by a reversible switch of genome DNA methylation (or epigenetic) patterns, which is driven by DNA inversions in the DNA methyltransferase genes. Observation of colony morphology is a simple and useful method to differentiate colonies with different characteristics, such as size, color, and opacity. This protocol describes how to study pneumococcal phase variation in colony morphology with a dissection microscope.

Intracolony variation in colony morphology in reassembled fossil ramose stenolaemate bryozoans from the Upper Ordovician (Katian) of the Cincinnati Arch region, USA

AbstractClusters of associated colony fragments discovered weathering out of bedding planes in the Upper Ordovician of the Cincinnati, Ohio, region provide a rare opportunity to quantify intracolony variation in ramose stenolaemate bryozoans. Sixteen colonies were reassembled as completely as possible from 198 fragments, and the following colony-level characters were measured: colony dimensions, branch link length and diameter, and branch order. Results indicate that branch link length and diameter systematically decrease as colonies grow via branch bifurcation. Branching ratio (i.e., the number of distal first-order branches divided by the number of immediately proximal second-order branches) appears to be more genetically than environmentally controlled and to be consistent among orders of stenolaemates and perhaps across the phylum. Colonies with endozones mined out by endoskeletozoans result in broken branches as opposed to pristine growing tips. This varies stratigraphically, perhaps in response to the distribution of the boring animals. The rarity of borers and the systematic proximal increase in branch diameter in these colonies suggest the zooids in the proximal portions of the colonies were alive at the time of colony death. If the time and effort can be invested in reassembling colonies, these morphometric data can then be applied to taxonomic, phylogenetic, and paleoenvironmental studies.

Altered Proteome of Burkholderia pseudomallei Colony Variants Induced by Exposure to Human Lung Epithelial Cells.

Burkholderia pseudomallei primary diagnostic cultures demonstrate colony morphology variation associated with expression of virulence and adaptation proteins. This study aims to examine the ability of B. pseudomallei colony variants (wild type [WT] and small colony variant [SCV]) to survive and replicate intracellularly in A549 cells and to identify the alterations in the protein expression of these variants, post-exposure to the A549 cells. Intracellular survival and cytotoxicity assays were performed followed by proteomics analysis using two-dimensional gel electrophoresis. B. pseudomallei SCV survive longer than the WT. During post-exposure, among 259 and 260 protein spots of SCV and WT, respectively, 19 were differentially expressed. Among SCV post-exposure up-regulated proteins, glyceraldehyde 3-phosphate dehydrogenase, fructose-bisphosphate aldolase (CbbA) and betaine aldehyde dehydrogenase were associated with adhesion and virulence. Among the down-regulated proteins, enolase (Eno) is implicated in adhesion and virulence. Additionally, post-exposure expression profiles of both variants were compared with pre-exposure. In WT pre- vs post-exposure, 36 proteins were differentially expressed. Of the up-regulated proteins, translocator protein, Eno, nucleoside diphosphate kinase (Ndk), ferritin Dps-family DNA binding protein and peptidyl-prolyl cis-trans isomerase B were implicated in invasion and virulence. In SCV pre- vs post-exposure, 27 proteins were differentially expressed. Among the up-regulated proteins, flagellin, Eno, CbbA, Ndk and phenylacetate-coenzyme A ligase have similarly been implicated in adhesion, invasion. Protein profiles differences post-exposure provide insights into association between morphotypic and phenotypic characteristics of colony variants, strengthening the role of B. pseudomallei morphotypes in pathogenesis of melioidosis.

Colony morphology variation of Burkholderia pseudomallei is associated with antigenic variation and O-polysaccharide modification.

Burkholderia pseudomallei is a CDC tier 1 select agent that causes melioidosis, a severe disease in humans and animals. Persistent infections are common, and there is currently no vaccine available. Lipopolysaccharide (LPS) is a potential vaccine candidate. B. pseudomallei expresses three serologically distinct LPS types. The predominant O-polysaccharide (OPS) is an unbranched heteropolymer with repeating d-glucose and 6-deoxy-l-talose residues in which the 6-deoxy-l-talose residues are variably replaced with O-acetyl and O-methyl modifications. We observed that primary clinical B. pseudomallei isolates with mucoid and nonmucoid colony morphologies from the same sample expressed different antigenic types distinguishable using an LPS-specific monoclonal antibody (MAb). MAb-reactive (nonmucoid) and nonreactive (mucoid) strains from the same patient exhibited identical LPS banding patterns by silver staining and indistinguishable genotypes. We hypothesized that LPS antigenic variation reflected modification of the OPS moieties. Mutagenesis of three genes involved in LPS synthesis was performed in B. pseudomallei K96243. Loss of MAb reactivity was observed in both wbiA (encoding a 2-O-acetyltransferase) and wbiD (putative methyl transferase) mutants. The structural characteristics of the OPS moieties from isogenic nonmucoid strain 4095a and mucoid strain 4095c were further investigated. Utilizing nuclear magnetic resonance (NMR) spectroscopy, we found that B. pseudomallei 4095a and 4095c OPS antigens exhibited substitution patterns that differed from the prototypic OPS structure. Specifically, 4095a lacked 4-O-acetylation, while 4095c lacked both 4-O-acetylation and 2-O-methylation. Our studies indicate that B. pseudomallei OPS undergoes antigenic variation and suggest that the 9D5 MAb recognizes a conformational epitope that is influenced by both O-acetyl and O-methyl substitution patterns.

Extension of the known distribution and depth range of the scleractinian coral Psammocora stellata: first record from a Taiwanese mesophotic reef

The scleractinian fauna of Taiwan is well-known and accounts for 316 species (Huang et al. 2014). However, most of the coral diversity surveys here have been limited to shallow waters, and benthic biodiversity below the 30-m depth limit of recreational diving remains largely unexplored. In February 2014, the starry coral Psammocora stellata (Verrill, 1866) was recorded for the first time in Taiwanese waters from a mesophotic reef off Green Island (121.47948° E, 22.63889° N). A free-living colony was observed lying on a sandy bottom, by scuba diving at 51 m depth (Fig. 1a). The brown colony was ~10 cm at its largest diameter and was composed of contorted branches with rounded tips. It was colonized by a variety of epibionts, mainly hydrozoans and bryozoans. Microscopic observations (Fig. 1b–c) showed the elongated shape of septa and multiple columellar processes, thus confirming the specimen (ASIZC0000991, Biodiversity Research Museum of Academia Sinica, Taiwan) identification based on the description given by Stefani et al. (2008). For a long time, the distribution of P. stellata has been considered as limited to Hawaii, Micronesia and the tropical Eastern Pacific (Veron 2000). Extension of the presence of this species to Australia, the Indian Ocean, the Red Sea, the Persian Gulf (see Stefani et al. 2008; but also Hoeksema and Best 1994) and now to Taiwan, suggests that this species has been overlooked or confused with other species (such as P. contigua), possibly due to the ecophenotypic variation in colony morphology (Stefani et al. 2008). In Taiwan, P. stellata could actually be restricted to mesophotic environments. This could explain why this species has gone unnoticed until now. Aside from extending the known distribution range of P. stellata and adding this species to the present knowledge of the scleractinian fauna of Taiwan, the observation presented here also draws attention to the possible importance of mesophotic benthic assemblages for the coral reef diversity in this area.

Enhanced intracellular survival and epithelial cell adherence abilities of Burkholderia pseudomallei morphotypes are dependent on differential expression of virulence-associated proteins during mid-logarithmic growth phase.

Comparative analyses were performed on the ability of wild-type and small colony variant of B. pseudomallei to adhere, invade and form plaques on human epithelial cells. In addition, proteomic analysis of these different colony morphotypes was also carried out. This research provides insights into the virulence and pathogenesis attributes of B. pseudomallei and contributes to better understand the pathogenesis of melioidosis.