Species Of Cellular Slime Molds Research Articles

Dictyostelid Cellular Slime Molds from Christmas Island, Indian Ocean.

Christmas Island (10°30'S, 105°40'E) is an Australian external territory located in the Indian Ocean, approximately 350 km south of Java and Sumatra and about 1,550 km northwest of the closest point on the Australian mainland. In May 2017, 20 samples of soil/humus were collected on Christmas Island and processed for dictyostelid cellular slime molds. Four species were recovered. Two of these (Dictyostelium purpureum and Cavenderia aureostipes) are common and widely distributed throughout the world, but two other species (Dictyostelium insulinativitatis sp. nov. and Dictyostelium barbarae sp. nov.) were found to be new to science and are described here.IMPORTANCE Reported here are the results of a study for dictyostelids carried out on Christmas Island, Indian Ocean. Six isolates representing four species of dictyostelid cellular slime molds were obtained from two of the four localities from which samples were collected on the island. Two of the species (Dictyostelium insulinativitatis and D. barbarae) belong to the Dictyosteliaceae, genus Dictyostelium, and are new to science. These are described based on both morphology and phylogeny. The diversity and abundance of dictyostelids on Christmas Island appear to be low, which might in part be due to the abundance of land crabs, which considerably reduce the extent of the litter layer on the forest floor.

Two new species of dictyostelid cellular slime molds in high-elevation habitats on the Qinghai-Tibet Plateau, China

Dictyostelid cellular slime molds (dictyostelids) are key components of soil microbes. The Qinghai-Tibet Plateau is characterized by unique and important forest types because of the considerable range in elevation which exists. During the period of 2012, 2013 and 2016, 12 species of dictyostelids were yielded from samples collected in this region, including two new species and three new records for China. Six other species were new records for this region. Ontogeny, morphology, ultrastructure and systematic molecular analyses (SSU & ITS) of D. minimum and D. multiforme confirm that they are Goup 4 new species. The ornamentation of the surface of dictyostelids’ spores is the first time to be observed until now. In the SSU phylogenetic tree generated in the present study, Synstelium, not assigned to order and family before, was assigned to the clade Acytosteliaceae in the Acytosteliales firstly. To our knowledge, the study reported herein is the first investigation of dictyostelid biodiversity carried out at elevations above 2000 m. Sorocarp size, sorus size, spore length, ratio of sorus and sorophore, and ratio of sorus and spore size were positively correlated with increasing elevation and no linear correlated with forest type, according to the results of linear regression analysis.

Dictyostelids from Jilin Province, China II

Four species of dictyostelid cellular slime molds (dictyostelids) in two genera were isolated from forest soil samples collected from Jilin Province in China. Dictyostelium recurvibasicum is new to science. Two of four species (D. longosporum and Polysphondylium tenuissimum) are new to China, and D. brefeldianum is recorded for the first time in the northern part of the country, being known previously only from Taiwan. Descriptions and illustrations are provided herein for these species based on our collections.

Evolutionary diversity of social amoebae N-glycomes may support interspecific autonomy.

Multiple species of cellular slime mold (CSM) amoebae share overlapping subterranean environments near the soil surface. Despite similar life-styles, individual species form independent starvation-induced fruiting bodies whose spores can renew the life cycle. N-glycans associated with the cell surface glycocalyx have been predicted to contribute to interspecific avoidance, resistance to pathogens, and prey preference. N-glycans from five CSM species that diverged 300-600 million years ago and whose genomes have been sequenced were fractionated into neutral and acidic pools and profiled by MALDI-TOF-MS. Glycan structure models were refined using linkage specific antibodies, exoglycosidase digestions, MALDI-MS/MS, and chromatographic studies. Amoebae of the type species Dictyostelium discoideum express modestly trimmed high mannose N-glycans variably modified with core α3-linked Fuc and peripherally decorated with 0-2 residues each of β-GlcNAc, Fuc, methylphosphate and/or sulfate, as reported previously. Comparative analyses of D. purpureum, D. fasciculatum, Polysphondylium pallidum, and Actyostelium subglobosum revealed that each displays a distinctive spectrum of high-mannose species with quantitative variations in the extent of these modifications, and qualitative differences including retention of Glc, mannose methylation, and absence of a peripheral GlcNAc, fucosylation, or sulfation. Starvation-induced development modifies the pattern in all species but, except for universally observed increased mannose-trimming, the N-glycans do not converge to a common profile. Correlations with glycogene repertoires will enable future reverse genetic studies to eliminate N-glycomic differences to test their functions in interspecific relations and pathogen evasion.

Dictyostelids from Jilin Province, China. I

Six species of dictyostelid cellular slime molds (dictyostelids) in two genera were isolated from soil samples collected from Jilin Province in China. Two of these species (Dictyostelium multistipes and D. gracile) are new to China, and D. clavatum is recorded for the first time in the northern part of the country, being known previously only from Taiwan. Descriptions and illustrations are provided for these species based on our collections.

A practice of Identifying the Species of cellular slime molds for Biology Education

A practice of Identifying the Species of cellular slime molds for Biology Education

Microcysts: The Third Developmental Pathway of Social Amoebozoans

Microcyst formation and germination, the least well studied of the three alternative developmental pathways open to the social amoebozoans, is also the simplest since it involves single cells. While classical studies profiled the morphological and biochemical changes that characterize microcyst differentiation, recent studies have focused on the molecular and evolutionary aspects of this system. Microcyst differentiation (encystment) is primarily triggered by high osmolarity and to a lesser extent by starvation. The transformation of an amoeba into a microcyst involves the formation of a cellulose cell wall as well as specific enzymatic and biochemical changes leading to dormancy. The spherical microcyst remains dormant as long as high osmotic conditions persist. When the osmolarity decreases, germination begins during which the cell wall is digested as the microcyst swells followed by the emergence of an amoeba. This rapid event typically takes 3-6 hours. The relationship between encystment and sporulation, which has evolutionary significance, is also reviewed with particular emphasis on the role and regulation of actin tyrosine phosphorylation. In light of the recent sequencing of the genomes of microcyst-forming cellular slime mold species, which will generate more research on microcysts, this critical review covers past and recent research to set the stage for future work on this alternative developmental pathway.

New species and new records of dictyostelids from Ukraine

Three species of dictyostelid cellular slime molds were isolated from forest soil, meadow soil and leaf litter collected from Yalta, Crimea, Ukraine. Dictyostelium globisporum is new to science; D. crassicaule and D. sphaerocephalum are new records from Ukraine. Descriptions and illustrations are given based on the Ukraine specimens.

Two species of dictyostelid cellular slime molds from Alaska

In sampling soils to survey dictyostelid cellular slime molds in Alaska we encountered two groups of isolates that have morphologies that differ from any previously described species within their group. We sequenced the nuclear small subunit ribosomal RNA gene (SSU rDNA) of selected isolates from the two groups and found sequences from both groups to be distinct from all previously described dictyostelid sequences. Phylogenetic analyses place one novel species in dictyostelid Group 2 and the other in Group 4 (Schaap et al. 2006). In this paper we formally describe as new these two species of cellular slime molds, Dictyostelium ammophilum sp. nov. and Dictyostelium boreale sp. nov., based on the combination of morphological and molecular characters.

A new species of cellular slime mold from southern Portugal based on morphology, ITS and SSU sequences

Sampling soils to look for dictyostelids in southern Portugal we found an isolate that has a morphology that differed from any previously described species of the group. We sequenced the internally transcribed spacer (ITS) and small subunit (SSU) genes of the nuclear ribosomal RNA and found that both sequences are distinct from all previously described sequences. Phylogenetic analyses place the new species in dictyostelid Group 3 (Rhizostelids) together with D. potamoides, with which it shares 65.8% identity for ITS and 96.6% for SSU. In this paper we describe a new species of cellular slime mold, Dictyostelium ibericum, based on morphological and molecular characters. It is a small species with polar granules in its spores.

Migration in Dictyostelium polycephalum

By comparing two species of cellular slime molds that have stalkless migration stages it is possible to gain interesting insights into how the cells move. In contrast to the familiar behavior of Dictyostelium discoideum, Dictyostelium polycephalum slugs can travel greater distances through soil and even can migrate through agar. In addition to the interest in the differences, these differences shed light on the mechanism of slug movement. Unlike D. discoideum, D. polycephalum does not have prestalk and prespore zones and severed sections of any part of these slugs move at a rate proportional to their length. This leads to the hypothesis that longer slugs move faster because the amoebae aligned along the inside of the slime sheath each contribute a forward push and the more extended the amoebae line is the faster the slug moves.

Migration in Dictyostelium polycephalum

By comparing two species of cellular slime molds that have stalkless migration stages it is possible to gain interesting insights into how the cells move. In contrast to the familiar behavior of Dictyostelium discoideum, Dictyostelium polycephalum slugs can travel greater distances through soil and even can migrate through agar. In addition to the interest in the differences, these differences shed light on the mechanism of slug movement. Unlike D. discoideum, D. polycephalum does not have prestalk and prespore zones and severed sections of any part of these slugs move at a rate proportional to their length. This leads to the hypothesis that longer slugs move faster because the amoebae aligned along the inside of the slime sheath each contribute a forward push and the more extended the amoebae line is the faster the slug moves.

The Ca2+/calcineurin-regulated cup gene family in Dictyostelium discoideum and its possible involvement in development.

Changes in free intracellular Ca2+ are thought to regulate several major processes during Dictyostelium development, including cell aggregation and cell type-specific gene expression, but the mechanisms involved are unclear. To learn more about Ca2+ signaling and Ca2+ homeostasis in this organism, we used suppression subtractive hybridization to identify genes up-regulated by high extracellular Ca2+. Unexpectedly, many of the genes identified belong to a novel gene family (termed cup) with seven members. In vegetative cells, the cup genes were up-regulated by high Ca2+ but not by other ions or by heat, oxidative, or osmotic stress. cup induction by Ca2+ was blocked completely by inhibitors of calcineurin and protein synthesis. In developing cells, cup expression was high during aggregation and late development but low during the slug stage. This pattern correlates closely with reported levels of free intracellular Ca2+ during development. The cup gene products are highly homologous, acidic proteins possessing putative ricin domains. BLAST searches failed to reveal homologs in other organisms, but Western analyses suggested that Cup-like proteins might exist in certain other cellular slime mold species. Localization experiments indicated that Cup proteins are primarily cytoplasmic but become cell membrane-associated during Ca2+ stress and cell aggregation. When cup expression was down-regulated by antisense RNA, the cells failed to aggregate. However, this developmental block was overcome by partially up-regulating cup expression. Together, these results suggest that the Cup proteins in Dictyostelium might play an important role in stabilizing and/or regulating the cell membrane during Ca2+ stress and/or certain stages of development.

Cellular Slime Molds in West Virginia Caves Including Notes on the Occurrence and Distribution of Dictyostelium Rosarium

Twenty-three caves in West Virginia were investigated for the presence of dictyostelid cellular slime molds. Nine species were recovered, but only three of these (Dictyostelium sphaerocephalum, D. mucoroides, and D. rosarium) were recorded from at least 10 different caves. In general, the distribution of cellular slime molds in caves appears to be rather patchy, but in the microsites where they do occur, these organisms exhibit surprisingly high levels of abundance and diversity. The presence of D. rosarium in West Virginia caves was unexpected, since this species has not yet been recorded from aboveground sites in the state. Previous reports of the occurrence and distribution of D. rosarium indicate that the species is most commonly associated with moderately dry or saline soils in arid habitats. However, the results of the present study suggest that D. rosarium is also able to exploit cave habitats to a greater extent than most other cellular slime mold species.

Cellular Slime Molds in West Virginia Caves including Notes on the Occurrence and Distribution of Dictyostelium rosarium

Twenty-three caves in West Virginia were investigated for the presence of dictyostelid cellular slime molds. Nine species were recovered, but only three of these (Dictyostelium sphaerocephalum, D. mucoroides, and D. rosarium) were recorded from at least 10 different caves. In general, the distribution of cellular slime molds in caves appears to be rather patchy, but in the microsites where they do occur, these organisms exhibit surprisingly high levels of abundance and diversity. The presence of D. rosarium in West Virginia caves was unexpected, since this species has not yet been recorded from aboveground sites in the state. Previous reports of the occurrence and distribution of D. rosarium indicate that the species is most commonly associated with moderately dry or saline soils in arid habitats. However, the results of the present study suggest that D. rosarium is also able to exploit cave habitats to a greater extent than most other cellular slime mold species.

Induction of cell fusion by a factor released by the cellular slime mold Polysphondylium pallidum

Heterokaryons and hybrid cells, which are extremely useful for research in cell biology, can be produced artificially by treating cells with either polyethylene glycol or certain inactivated viruses that alter the plasma membrane. We report here a novel cell-fusion inducing factor secreted by CK-8 strain cells of cellular slime mold Polysphondylium pallidum. Treatment of other strains or other species of cellular slime molds, such as NC-4 of Dictyostelium discoideum with the diluted fraction, containing molecules larger than 50 kDa, of the conditioned medium of CK-8 cell culture induces cell fusion at high frequency and produces multinucleated large cells. This cell fusion is inducible between cells of either a single strain or of two different strains of cellular slime molds.

Cell-division inhibitor produced by a killer strain of cellular slime mold Polysphondylium pallidum: (cellular slime mold/Polysphondylium pallidum/cell-division inhibitor/killer strain).

The killer strain CK-8 of cellular slime mold Polysphondylium pallidum produces a cell-division inhibitor, in addition to a killer factor. This inhibitor represses cell division of many strains and species of cellular slime molds, except CK-8 itself and its complementary mating-type strain. It is sensitive to both heat and trypsin, and capable of binding to Con A. Its apparent molecular mass is more than 100 kDa. Repression of cell division by this inhibitor is reversed by trypsin treatment of the cells.

Identification and purification of the cell surface glycoprotein homologous to PsA in different species of cellular slime mold on the basis of a shared carbohydrate epitope

AbstractThe monoclonal antibodies MUD1 and MUD50 recognize peptide and carbohydrate epitopes, respectively, on the Dictyoste‐lium discoideum developmentally regulated cell surface glycoprotein PsA. PsA is a putative pre‐spore cell adhesion molecule during the slug stage and is anchored to the cell membrane via a phos‐phatidylinositol glycan. Here we report on the presence of a PsA‐like homolog in several Dictyo‐stelium species. The MUD1 epitope is mostly confined to the D. discoideum complex, and only one non‐D. discoideum strain reacted strongly with this antibody. By contrast, the mAb MUD50 recognises a homologous molecule in several Dictyostelium species that do not react with MUD1. With mAb MUD50 immunoaffinity chromatography, it was possible to purify and obtain an amino‐terminal sequence for the PsA homolog from the Dictvoste‐lium sp. strain ZA3A and from one strain of D. pur‐pureum.

Clonal Diversity in Populations of Polysphondylium Pallidum, A Cellular Slime Mold

Populations of the cellular slime mold Polysphondylium pallidum contain clones that differ in their abilities to use bacterial resources. We found abundant diversity among isolates obtained from plots of several square metres and from single soil cores 1.1 cm in diameter. The variation we were measuring was not due to genetic changes induced by our manipulation. Previously, isolation of different species of cellular slime molds from sample areas, metres to hectares in extent, has prompted studies of mechanisms of species coexistence in the face of assumed competition for bacterial resources. We conclude that competition has not only failed to eliminate different species from the community but has failed to eliminate clonal diversity from within species. Previous explanations of species coexistence need reevaluation.

Dispersal of Cellular Slime Molds by Two Soil Invertebrates

Earthworms and pillbugs are known to feed upon substrates likely to be inhabited by cellular slime molds. Gut contents of earthworms (Aporrectodea calignosa and Octolasion tyrtaeum) and pillbugs (Armadillidium nasatum and A. vulgare) collected from northeastern Kansas were found to contain living cellular slime molds. Eleven species of dictyostelid cellular slime molds were isolated from soil samples and gut contents of soil macrofauna. Lumbricus terrestris specimens were force-fed separate spore and myxamoeba suspensions of Dictyostelium mucoroides, and the results suggest that spores can survive passage through the gut better than myxamoebae. Pillbugs were fed spores of D. purpureum and Polysphondylium violaceum, and these dictyostelids were isolated from fecal pellets. Potential benefits of short range dispersal of slime mold propagules by invertebrates are discussed.