Spore-like Structures Research Articles

Histoplasmosis: A Mimicker of Granulomatosis with Polyangitis

A 31-year-old male from the southern part of India with no known comorbidities presented with painful oral erosions over his palate following a dental procedure. Over 2 months, it progressed to the desquamation of blackish necrotic skin, gingival hypertrophy associated with intermittent fever and odynophagia. He had elevated acute-phase reactants. Biopsy of the gingiva showed necrotising vasculitis. ANCA was weakly positive for the cytoplasmic pattern by immunofluorescence. The HRCT chest showed a single cavitating nodule in the right upper lobe and a non-cavitary nodule in the left upper lobe with right maxillary sinus thickening. With the above clinical and biopsy findings, granulomatosis with polyangiitis was the first consideration. He was referred to our centre since the oral lesions did not improve and nodular swellings developed on the palate. The examination showed cervical lymphadenopathy, which was subjected to an excision biopsy. It showed extensive areas of necrosis with karyorrhectic debris and numerous intracellular and extracellular round-to-ovoid spore-like structures. Special stains were positive for histoplasmosis. Abdomen imaging showed adrenal enlargement. Cultures were negative, which could be due to the fact that he was on multiple medications. He was treated with amphotericin and itraconazole. His symptoms improved. But later, he had worsening clinical parameters suggestive of a progressive disseminated form of histoplasmosis. In spite of aggressive efforts, he couldn’t be resuscitated owing to the dissemination of the organism. Even though considered to be more common in immunosuppressed individuals in nonendemic areas, it is reported in immunocompetent individuals as well and should be strongly suspected if the clinical picture fits so for early diagnosis and aggressive management to prevent fatal complications. There have been only fewer case reports of histoplasmosis from the southern part of India. ANCA is only rarely reported false positively in histoplasmosis.

Cryptosporulation in Kurthia spp. forces a rethinking of asporogenesis in Firmicutes.

Endosporulation is a complex morphophysiological process resulting in a more resistant cellular structure that is produced within the mother cell and is called endospore. Endosporulation evolved in the common ancestor of Firmicutes, but it is lost in descendant lineages classified as asporogenic. While Kurthia spp. is considered to comprise only asporogenic species, we show here that strain 11kri321, which was isolated from an oligotrophic geothermal reservoir, produces phase-bright spore-like structures. Phylogenomics of strain 11kri321 and other Kurthia strains reveals little similarity to genetic determinants of sporulation known from endosporulating Bacilli. However, morphological hallmarks of endosporulation were observed in two of the four Kurthia strains tested, resulting in spore-like structures (cryptospores). In contrast to classic endospores, these cryptospores did not protect against heat or UV damage and successive sub-culturing led to the loss of the cryptosporulating phenotype. Our findings imply that a cryptosporulation phenotype may have been prevalent and subsequently lost by laboratory culturing in other Firmicutes currently considered as asporogenic. Cryptosporulation might thus represent an ancestral but unstable and adaptive developmental state in Firmicutes that is under selection under harsh environmental conditions.

New Findings of Microfossils in the Orgueil Meteorite

The Orgueil meteorite was studied using a TESCAN VEGA 3 scanning electron microscope. As a result, new microfossils were found, including a fragment of a pennate diatom shell, tubular structures with double porous cell walls (prasinophytes?), hollow spheres with a process (acritarchs?), and spore-like structures. The problem of the cometary origin of the Orgueil meteorite is discussed.

Evidence of sporulation capability of the ubiquitous oil reservoir microbe Halanaerobium congolense

Subsurface lineages of microorganisms are often questioned for their autochthonous nature. We hypothesize that sporulation is critical to the delivery and ubiquity of Halanaerobium congolense in global subsurface hydrocarbon reservoirs, forming spores, or spore-like structures in order to survive surface conditions, and thriving in subsurface reservoir conditions. Genomic analysis of H. congolense revealed the presence of various genes essential for sporulation, many of which are homologous to those involved in various stages of sporulation in clostridia and bacilli. Transcriptomics revealed transcription of sporulation genes in H. congolense grown in sub-optimal conditions. This is further supported by microscopy evidence of spore-like structures.

Infection of the Carpathian brook lamprey (Eudontomyzon danfordi Regan, 1911) with a dermocystid parasite in the Tisza River Basin, Hungary.

The Carpathian brook lamprey (Eudontomyzon danfordi Regan, 1911) is an endemic protected species of Cephalaspidomorphi in the Carpathian Basin. No parasites have become known from these jawless vertebrates to date. Here, the authors describe an infection from a single specimen manifesting in protuberant skin cysts 7-10mm in diameter, scattered on the body surface. Similar dermal infection was observed in 25 of the 274 lampreys recorded in the population survey. Skin cysts filled with round spore-like structures of a dermocystid parasite were found. These particles measured 8-14µm in diameter and had an about 0.5µm thick wall, and containing mainly a granular mass and a relatively scarce plasma. No hyphae were recorded. Despite conspicuous morphological changes in the skin, no inflammatory reactions were found. The molecular analysis of 18S rDNA showed similarity to dermocystid species of several fish species but differed from them approximately by 2%. This is the first record of a dermocystid parasite infecting a jawless vertebrate.

Identification of Histoplasma causing an unexplained disease cluster in Matthews Ridge, Guyana

Here, we report the identification of Histoplasma causing an unexplained disease cluster in Matthews Ridge, Guyana. In March 2019, 14 employees of Chongqing Bosai Mining Company, China, working in a manganese mining of Guyana, had unexplained fever, and two of them died. We obtained lung and brain tissues as well as the blood samples from the two deceased cases (patient No. 1 and 2), and bronchoscopy lavages and cerebrospinal fluid samples from one severe case (patient No. 3), respectively. All samples were tested by pathological examination, high-throughput sequencing, and real-time PCR. Pathological detection showed the presence of spore-like structures in the lung tissue of patient No. 1, indicating a fungal infection in this patient. Nanopore sequencing identified the existing of H. capsulatum in the lung tissue sample within 13 h. Next-generation sequencing identified specific fragments of H. capsulatum in all of the samples tested (lung, brain and blood serum from the deceased cases, and plasma from the severe case). Real-time PCR assays did not reveal any viral infection related to transmission from bat feces. We conclude that H. capsulatum was the causative pathogen of this disease cluster based on epidemiologic, clinical, pathological and nucleic acid evidence.

Giant viruses as protein-coated amoeban mitochondria?

Mimivirus' genome includes parts of 5S, 16S and 23S ribosomal RNAs encoded by Acanthamoeba's mitogenome, the giant virus' host. Two non-exclusive hypotheses for rRNA remnants in giant viruses are examined: 1. mitogenomes invade viral genomes as they do for nuclear chromosomes (producing numts); 2. megaviral genomes evolved from an ancestral mitogenome. Alignment analyses confirm mitochondrial, rather than alphaproteobacterial origins of megaviral rRNAs. Other mitogenes have likely megaviral homologues. These megaviral homologues coevolve to much larger extents than candidate rRNA homologues, suggesting rRNA decay in viruses. Megaviral mitogene homologues overall follow mitochondrial gene order, suggesting mitogenome ancestry. Ancestral synteny decreases with megaviral genome size, suggesting that subsequent mitogene insertions blur ancestral gene order. Putative defenses against DNA invasion conserve mitogene order in short megaviral genomes. Synteny between mitogenome and megaviral genomes confirms the RNA/DNA polymerase-homologies-based hypothesis that giant viruses have mitochondrial-like ancestors, viral rRNA remnants are corollary of mitogenomic origins of megaviral genomes. Note that giant viruses, mitochondria and bacterial spores all have double membranes, spores and viruses have protein coats. Mitochondria might occasionally form spore-like structures that drifted into megaviruses. These missing links could confirm mitogenome ancestry of giant viruses rather than giant virus ancestry of mitochondria.

In vivo confocal microscopic characteristics of microsporidial keratoconjunctivitis in immunocompetent adults

Background/aimsTo describe in vivo confocal microscopy (IVCM) features of microsporidial keratoconjunctivitis in immunocompetent adult patients.MethodsPatients suspected clinically to be suffering from microsporidial keratoconjunctivitis (ie, presence of unilateral follicular and/or papillary...

Experiments on the life cycle and factors affecting reproduction of Sphaerosporella brunnea provide evidence for rapid asexual propagation by conidiospores and for homothallism in an ectomycorrhizal competitor of cultivated truffle species

Sphaerosporella brunnea is a pioneer and opportunist ectomycorrhizal species, and the most common fungal competitor in nurseries producing plants mycorrhized with Tuber species. Our objective was to learn more about its life cycle as the first step to manage its presence in greenhouses. Conidiation and formation of resting spore-like structures were found to be triggered by aeration and to be highest on CMA medium. In pot experiments S. brunnea was able to form ectomycorrhizas and ascocarps rapidly, in 2 and 3 months respectively, if substratum moisture was high. Both mycelia and conidiospores were effective sources of inoculum for mycorrhization. This species seems to be homothallic as apothecia have been obtained after inoculations with single monospore isolates. Propagation by mitospores and homothallism are poorly documented in ECM fungi, therefore these results may be of fundamental interest beyond the question of greenhouse management.

Methanotrophic activity in Carboniferous coalbed rocks

Carboniferous coalbed rocks originating from the Lublin Coal Basin (South-East Poland) were investigated for the presence and activity of aerobic methanotrophic bacteria. Laboratory studies of samples collected from 914 to 1004m below earth's surface and performed at 30°C, 100% water capacity (WHC) and 10% v/v headspace CH4 revealed microbial methane oxidation which ranged from 0.13 to 0.75μM CH4 g−1day−1. Methanotrophic activity (MA) was also investigated as a function of temperature (5–30°C), moisture content (25–200% WHC) and substrate concentration (1–30% v/v CH4). The highest MA was recorded at 30°C, 100% WHC and 20% CH4 v/v, indicating the mesophilic and microaerophilic character of methanotrophic bacteria (MB) present in the coalbed. Lack of detectable MA at 5 and 10°C shows narrow temperature tolerance of MB, which may result from a long-term isolation of the bacterial habitat and stability of thermal conditions in the coalbed.Cryo-SEM revealed presence in the investigated rocks of bacteria (c.a. 2–2.5μm long and 0.5–1μm wide) and spore-like structures (0.5–1μm in diameter). These observations were confirmed by fluorescence in situ hybridization with probes Mg705 (5′fluoresceine), Mg84 (5′Cy3) and Ma450 (5′Cy5), which showed that enrichments in NMS medium contain types I and II MB of similar size. Identification performed with the use of DNA amplification of 16S rRNA targeted group specific primers confirmed the presence of bacteria belonging to Methylosinus, Methylomicrobium, Methylocystis and Methylocaldum. Here we show that coalbed rocks constitute a habitat for diverse MB.

Subseafloor basalts as fungal habitats

Abstract. The oceanic crust is believed to host the largest potential habitat for microbial life on Earth, yet, still we lack substantial information about the abundance, diversity, and consequence of its biosphere. The last two decades have involved major research accomplishments within this field and a change in view of the ocean crust and its potential to harbour life. Here fossilised fungal colonies in subseafloor basalts are reported from three different seamounts in the Pacific Ocean. The fungal colonies consist of various characteristic structures interpreted as fungal hyphae, fruit bodies and spores. The fungal hyphae are well preserved with morphological characteristics such as hyphal walls, septa, thallic conidiogenesis, and hyphal tips with hyphal vesicles within. The fruit bodies consist of large (∼50–200 µm in diameter) body-like structures with a defined outer membrane and an interior filled with calcite. The fruit bodies have at some stage been emptied of their contents of spores and filled by carbonate-forming fluids. A few fruit bodies not filled by calcite and with spores still within support this interpretation. Spore-like structures (ranging from a few µm to ∼20 µm in diameter) are also observed outside of the fruit bodies and in some cases concentrated to openings in the membrane of the fruit bodies. The hyphae, fruit bodies and spores are all closely associated with a crust lining the vein walls that probably represent a mineralized biofilm. The results support a fungal presence in deep subseafloor basalts and indicate that such habitats were vital between ∼81 and 48 Ma.

Identification and Characterization of a Spore-Like Morphotype in Chronically Starved Mycobacterium avium Subsp. Paratuberculosis Cultures

Mycobacteria are able to enter into a state of non-replication or dormancy, which may result in their chronic persistence in soil, aquatic environments, and permissive hosts. Stresses such as nutrient deprivation and hypoxia provide environmental cues to enter a persistent state; however, a clear definition of the mechanism that mycobacteria employ to achieve this remains elusive. While the concept of sporulation in mycobacteria is not novel, it continues to spark controversy and challenges our perceptions of a non-replication. We investigated the potential role of sporulation in one-year old broth cultures of Mycobacterium subsp. paratuberculosis (MAP).We show that dormant cultures of MAP contain a mix of vegetative cells and a previously unknown morphotype resembling a spore. These spore-like structures can be enriched for using sporulating media. Furthermore, purified MAP spore forms survive exposure to heat, lysozyme and proteinase K. Heat-treated spores are positive for MAP 16SrRNA and IS900. MAP spores display enhanced infectivity as well as maintain acid-fast characteristics upon germination in a well-established bovine macrophage model. This is the first study to demonstrate a new MAP morphotype possessing spore-like qualities. Data suggest that sporulation may be a viable mechanism by which MAP accomplishes persistence in the host and/or environment. Thus, our current understanding of mycobacterial persistence, pathogenesis, epidemiology and rational drug and vaccine design may need to be reevaluated.

Agrobacterium‐mediated transformation of the barley pathogen Ramularia collo‐cygni with fluorescent marker tags and live tissue imaging of infection development

Ramularia collo‐cygni, the causal agent of ramularia leaf spot disease in barley was transformed to express the green fluorescent protein and DsRed fluorescent protein using a combined protoplast and Agrobacterium tumefaciens‐mediated transformation technique. Regenerated protoplasts from mycelial fragments were transformed with A. tumefaciens strain AGL1 containing either pCAMBgfp or pCAMBDsRed plasmids. Two different isolates of R. collo‐cygni were transformed and several stable transformants were recovered. These transformants infected detached barley leaves and characteristic swan’s‐neck‐shaped conidiophores were seen on detached leaves 9 days after inoculation, as well as spore‐like structures formed from hyphal swellings. This first successful transformation of R. collo‐cygni has enabled better description of the stages of disease development and pathogen behaviour during the endophytic/asymptomatic stage of its life cycle.

Amycolatopsis tucumanensis sp. nov., a copper-resistant actinobacterium isolated from polluted sediments

A novel actinomycete strain, ABO(T), isolated from copper-polluted sediments showed remarkable copper resistance as well as high bioaccumulation abilities. Classical taxonomic methods, including chemotaxonomy and molecular techniques, were used to characterize the isolate. Strain ABO(T) developed a honey-yellow substrate mycelium on all ISP media tested. Abundant, white, aerial mycelium was only formed on ISP 2, 5 and 7 and MM agar. Both types of hyphae fragmented into squarish rod-shaped elements. The aerial mycelium displayed spore-like structures with smooth surfaces in long, straight to flexuous chains. The organism has a type-IV cell wall lacking mycolic acids and type-A whole-cell sugar pattern (meso-diaminopimelic acid, arabinose and galactose) in addition to a phospholipid type-II profile. 16S rRNA gene sequence studies indicated that this organism is a member of the family Pseudonocardiaceae and that it forms a monophyletic clade with Amycolatopsis eurytherma NT202(T). The DNA-DNA relatedness of strain ABO(T) to A. eurytherma DSM 44348(T) was 39.5 %. It is evident from these genotypic and phenotypic data that strain ABO(T) represents a novel species in the genus Amycolatopsis, for which the name proposed is Amycolatopsis tucumanensis sp. nov. The type strain is ABO(T) (=DSM 45259(T) =LMG 24814(T)).

CAMP promotes hyphal branching in Mucor globosus

The growth pattern of Mucor globosus cultured on a medium with or without cyclic adenosine monophosphate (cAMP) was examined. Branching remarkably increased in a mycelium grown on an agar medium containing cAMP. In submerged culture containing cAMP, some sporangiospores grew spherically and formed yeast-like cells, and others showed hyphal growth. These hyphae showed septation and swelling and formed spore-like structures. When these hyphae were transferred to cAMP-free medium, a germ tube emerged from each compartment. These results show that cAMP has two different effects on the development of hyphae: one is the promotion of branching, and the other is the suppression of polarized growth.

CAMP promotes hyphal branching in <i>Mucor globosus</i>

The growth pattern of Mucor globosus cultured on a medium with or without cyclic adenosine monophosphate (cAMP) was examined. Branching remarkably increased in a mycelium grown on an agar medium containing cAMP. In submerged culture containing cAMP, some sporangiospores grew spherically and formed yeast-like cells, and others showed hyphal growth. These hyphae showed septation and swelling and formed spore-like structures. When these hyphae were transferred to cAMP-free medium, a germ tube emerged from each compartment. These results show that cAMP has two different effects on the development of hyphae: one is the promotion of branching, and the other is the suppression of polarized growth.

Inhibitory effect of Pseudomonas spp. on the development of Botrytis cinerea and Penicillium expansum

The influence of antagonistic Pseudomonas spp. on the development of Botrytis cinerea and Penicillium expansum was studied in liquid cultures. Two strains of Pseudomonas spp. (B194 and B224), originally isolated from apple leaves and fruits, respectively, inhibited spore germination and germ tube elongation of B. cinerea or P. expansum. The inhibitory effect depended on the concentration of bacteria in the cultures. After a prolonged time of incubation (48–76 h) lysis and fragmentation of hyphae of both fungi was observed. In some cases the hyphae of B. cinerea developed abnormally if the bacterial strains were present – the hyphal tips were swollen and ball-shaped spore-like structures aggregated in chains were formed.

AN UNUSUAL INTRAERYTHROCYTIC PARASITE OF PARABLENNIUS CORNUTUS FROM SOUTH AFRICA

An intertidal horned blenny, Parablennius cornutus, captured at De Hoop Nature Reserve, South Africa, was found to harbor an unusual blood parasite and the haemogregarine Haemogregarina bigemina. In Giemsa-stained blood films, the enigmatic parasite occurred primarily as intraerythrocytic ringlike stages, with unstained centers and peripheral bands of beaded chromatin, not unlike Haemohormidium spp. Larger forms of the same organism stained pink with Giemsa, with nuclei occurring as 4-8 minute structures around the parasite body or distributed within it. These larger parasites apparently segmented into up to 8 individuals that were rounded or oval with deep-stained, comma-shaped or polar regions surrounding blue cytoplasm. Extracellular, binucleate, sporelike structures in clusters of as many as 16 individuals were also seen in blood films. Praniza larvae of the isopod Gnathia africana were seen in histological sections of gill tissue. Examination of spleen tissue by transmission electron microscopy showed intraerythrocytic organisms with ultrastructural characteristics like those of Haematractidium scombri, namely, a single boundary membrane, sometimes closely apposed nuclei with nucleoli, and profiles of dense material of variable structure. It is concluded that the parasite is probably related to Haemohormidium spp. and H. scombri, but it also shares features with some Microsporida.

Characterization and description of Anaeromyxobacter dehalogenans gen. nov., sp. nov., an aryl-halorespiring facultative anaerobic myxobacterium.

Five strains were isolated which form a physiologically and phylogenetically coherent group of chlororespiring microorganisms and represent the first taxon in the Myxobacteria capable of anaerobic growth. The strains were enriched and isolated from various soils and sediments based on their ability to grow using acetate as an electron donor and 2-chlorophenol (2-CPh) as an electron acceptor. They are slender gram-negative rods with a bright red pigmentation that exhibit gliding motility and form spore-like structures. These unique chlororespiring myxobacteria also grow with 2,6-dichlorophenol, 2,5-dichlorophenol, 2-bromophenol, nitrate, fumarate, and oxygen as terminal electron acceptors, with optimal growth occurring at low concentrations (<1 mM) of electron acceptor. 2-CPh is reduced by all strains as an electron acceptor in preference to nitrate, which is reduced to ammonium. Acetate, H(2), succinate, pyruvate, formate, and lactate were used as electron donors. None of the strains grew by fermentation. The 16S ribosomal DNA (rDNA) sequences of the five strains form a coherent cluster deeply branching within the family Myxococcaceae within the class Myxobacteria and are mostly closely associated with the Myxococcus subgroup. With the exception of anaerobic growth and lack of a characteristic fruiting body, these strains closely resemble previously characterized myxobacteria and therefore should be considered part of the Myxococcus subgroup. The anaerobic growth and 9.0% difference in 16S rDNA sequence from those of other myxobacterial genera are sufficient to place these strains in a new genus and species designated Anaeromyxobacter dehalogenans. The type strain is 2CP-1 (ATCC BAA-258).

Lachnospira pectinoschiza sp. nov., an anaerobic pectinophile from the pig intestine.

Pectinophiles are bacteria that utilize pectin and only a few related compounds as substrates. Obligately anaerobic pectinophiles have been isolated from the intestinal tracts and gingivae of humans and from the rumina of cattle. We isolated three strains of pectinophilic bacteria from colonic contents of pigs but were unable to isolate pectinophiles from the rumen contents of four sheep, even when the animals were fed a high-pectin diet. The pectinophiles isolated from pigs were strictly anaerobic, motile, gram-positive rods (0.36 to 0.56 by 2.4 to 3.1 microns). Pectin, polygalacturonic acid, and gluconate were the only substrates that supported rapid growth. All three strains grew slowly on either lactose or cellobiose and fermented fructose after a lag of several days. Pectin was degraded by means of an extracellular pectin methylesterase and a Ca(2+)-dependent exopectate lyase. A comparison of the 16S rRNA sequences of these isolates with the 16S rRNA sequences of other gram-positive bacteria revealed a specific relationship with Lachnospira multipara (level of similarity, 94%). The Gram reaction, formation of spore-like structures, and the utilization of lactose and cellobiose differentiated the pig isolates from previously described pectinophiles. The pig isolates represent a previously undescribed species of the genus Lachnospira, for which we propose the name Lachnospira pectinoschiza.