Sporotrichosis is a subcutaneous mycosis caused by pathogenic species of the Sporothrix genus. A new emerging species, Sporothrix brasiliensis, is related to cat-transmitted sporotrichosis and has ...severe clinical manifestations. The cell wall of pathogenic fungi is a unique structure and impacts directly on the host immune response. We reveal and compare the cell wall structures of Sporothrix schenckii and S. brasiliensis using high-pressure freezing electron microscopy to study the cell wall organization of both species. To analyze the components of the cell wall, we also used infrared and 13C and 1H NMR spectroscopy and the sugar composition was determined by quantitative high-performance anion-exchange chromatography. Our ultrastructural data revealed a bi-layered cell wall structure for both species, including an external microfibrillar layer and an inner electron-dense layer. The inner and outer layers of the S. brasiliensis cell wall were thicker than those of S. schenckii, correlating with an increase in the chitin and rhamnose contents. Moreover, the outer microfibrillar layer of the S. brasiliensis cell wall had longer microfibrils interconnecting yeast cells. Distinct from those of other dimorphic fungi, the cell wall of Sporothrix spp. lacked α-glucan component. Interestingly, glycogen α-particles were identified in the cytoplasm close to the cell wall and the plasma membrane. The cell wall structure as well as the presence of glycogen α-particles varied over time during cell culture. The structural differences observed in the cell wall of these Sporothrix species seemed to impact its uptake by monocyte-derived human macrophages. The data presented here show a unique cell wall structure of S. brasiliensis and S. schenckii during the yeast parasitic phase. A new cell wall model for Sporothrix spp. is therefore proposed that suggests that these fungi molt sheets of intact cell wall layers. This observation may have significant effects on localized and disseminated immunopathology.
We report on the effect of a weak magnetic field applied on an iodine cell used to frequency stabilize a laser. A 1.5
μ
m laser is frequency tripled in order to excite the molecular transitions at ...0.51
μ
m and frequency locked on a hyperfine line. With this frequency reference, we report short-term stability about
3
×
10
-
14
τ
-
1
/
2
, with a minimum value of
4
×
10
-
15
at 200 s. The lower part of
10
-
15
frequency stability domain is reached, in our case, only by adding an efficient magnetic shield around the sealed quartz iodine cell. In order to quantify the Zeeman effect, we applied magnetic fields of several
×
10
-
4
T on the cell containing the iodine vapour. The Zeeman effect affects the lineshape transition in such a way that we observe a modification of the laser frequency. We have measured this linear Zeeman shift at
(
1062
±
6
)
×
10
4
Hz/T for the
a
1 hyperfine component of the R(34) 44-0 transition, near 514 nm by applying a magnetic field along the cell. Thus, in case of uncontrolled magnetic fields of an order of magnitude of 1
×
10
-
4
T, the frequency stability is limited in the upper of the
10
-
14
domain.
and
are usually associated to sporotrichosis, a subcutaneous mycosis worldwide distributed. Comparative analyses between these two species indicate they contain genetic and physiological differences ...that are likely to impact the interaction with host cells. Here, we study the composition of the cell wall from conidia, yeast-like cells and germlings of both species and found they contained the same sugar composition. The carbohydrate proportion in the
wall was similar across the three cell morphologies, with exception in the chitin content, which was significantly different in the three morphologies. The cell wall from germlings showed lower rhamnose content and higher glucose levels than other cell morphologies. In
, the wall sugars were constant in the three morphologies, but glucose was lower in yeast-like cells. In
cells most of chitin and β1,3-glucan were underneath wall components, but in
germlings, chitin was exposed at the cell surface, and β1,3-glucan was found in the outer part of the conidia wall. We also compared the ability of these cells to stimulate cytokine production by human peripheral blood mononuclear cells. The three
morphologies stimulated increased levels of pro-inflammatory cytokines, when compared to
cells; while the latter, with exception of conidia, stimulated higher IL-10 levels. Dectin-1 was a key receptor for cytokine production during stimulation with the three morphologies of
, but dispensable for cytokine production stimulated by
germlings. TLR2 and TLR4 were also involved in the sensing of
cells, with a major role for the former during cytokine stimulation. Mannose receptor had a minor contribution during cytokine stimulation by
yeast-like cells and germlings, but
conidia and
yeast-like cells stimulated pro-inflammatory cytokines via this receptor. In conclusion,
and
, have similar wall composition, which undergoes changes depending on the cell morphology. These differences in the cell wall composition, are likely to influence the contribution of immune receptors during cytokine stimulation by human monocytes.
Sporotrichosis is known as a subacute or chronic infection, which is caused by thermodimorphic fungi of the genus
. It is a cosmopolitan infection, which is more prevalent in tropical and subtropical ...regions and can affect both humans and other mammals. The main etiological agents causing this disease are
,
, and
, which have been recognized as members of the
pathogenic clade. Within this clade,
is considered the most virulent species and represents an important pathogen due to its distribution and prevalence in different regions of South America, such as Brazil, Argentina, Chile, and Paraguay, and Central American countries, such as Panama. In Brazil,
has been of great concern due to the number of zoonotic cases that have been reported over the years. In this paper, a detailed review of the current literature on this pathogen and its different aspects will be carried out, including its genome, pathogen-host interaction, resistance mechanisms to antifungal drugs, and the caused zoonosis. Furthermore, we provide the prediction of some putative virulence factors encoded by the genome of this fungal species.
Sporotrichosis is an increasing threat for humans, affecting mainly skin and subcutaneous tissues but that can cause disseminated infection in immunocompromised patients.
, and
are the main ...etiological agents of this mycosis, and each species show different virulence levels. The gold standard to assess fungal virulence is the mouse model that is expensive and time-consuming. Thus, invertebrate models have been reported as an alternative for the evaluation of fungal virulence. Here, we assessed whether
larvae could be a new alternative to study
spp. virulence.
larvae were inoculated with different doses of
, and
, and animal mortality, cytotoxicity, and immunological parameters were analyzed, including the ability to stimulate immunological priming.
Mortality curves demonstrated that yeast-like cells were the best fungal morphology to kill larvae and showed a similar ranking in virulence than that reported in other animal models, ie, being
and
the species with the highest and lowest virulence, respectively. The usefulness of this model was validated with the analysis of several
strains with different virulence degrees, and changes in cytotoxicity, humoral and cellular immunological parameters. Low-virulence strains stimulated low levels of cytotoxicity, phenoloxidase activity, and hemocyte countings, and these immunological cells poorly uptake fungi. Moreover, using recombinant Gp70 from
immunological priming was stimulated in larvae and this protected against a lethal dose of fungal cells from any of the three species under study.
The study demonstrated that
larvae are an appropriate alternative invertebrate model to analyze the virulence of
, and
. Additionally, hemocyte levels, phenoloxidase activity, cytotoxicity, uptake by hemocytes, and immunological priming are biological parameters that can be used to study the
interaction.
There is worldwide concern about the constant increase in infections caused by
species that are multiresistant to antifungal drugs. The most common candidiasis is caused by
, however, the species of ...the
complex and
are emerging opportunistic pathogens, which isolation from clinical samples has significantly increased in the past years. The special interest in the study of these species lies in their ability to evade the action of antifungal drugs, such as amphotericin B, azoles, and echinocandins. In addition, the phenotypic changes of these species have given them the ability to easily adapt to environmental changes, including the host milieu and immunity. In this paper, a detailed review of the current literature on the
complex and
is shown, analyzing aspects such as biology, immune response, putative virulence factors, infection, treatment, and the current strategies for diagnosis.
Sporotrichosis is a cutaneous mycosis that affects humans and animals and has a worldwide distribution. This infection is mainly caused by Sporothrix schenckii, Sporothrix brasiliensis, and ...Sporothrix globosa. Current research about anti-Sporothrix immunity has been mainly focused on S. schenckii and S. brasiliensis, using different types of human or animal immune cells. Granulocytes are a group of cells relevant for cytokine production, with the capacity for phagocytosis and the generation of neutrophil extracellular traps (NETs). Considering their importance, this study aimed to compare the capacity of human granulocytes to stimulate cytokines, uptake, and form NETs when interacting with different Sporothrix species. We found that conidia, germlings, and yeast-like cells from S. schenckii, S. brasiliensis, and S. globosa play an important role in the interaction with these immune cells, establishing morphology- and species-specific cytokine profiles. S. brasil-iensis tended to stimulate an anti-inflammatory cytokine profile, whilst the other two species had a proinflammatory one. S. globosa cells were the most phagocytosed cells, which occurred through a dectin-1-dependent mechanism, while the uptake of S. brasiliensis mainly occurred via TLR4 and CR3. Cell wall N-linked and O-linked glycans, along with β-1,3-glucan, played a significant role in the interaction of these Sporothrix species with human granulocytes. Finally, this study indicates that conidia and yeast-like cells are capable of inducing NETs, with the latter being a better stimulant. To the best of our knowledge, this is the first study that reports the cytokine profiles produced by human granulocytes interacting with Sporothrix cells.
Mannans are components of the fungal wall attached to proteins via
- or
-linkages. In
, Och1 is an α1,6-mannosyltransferase that adds the first mannose unit to the
-linked mannan outer chain; whereas ...Pmr1 is an ion pump that imports Mn
into the Golgi lumen. This cation is the cofactor of Golgi-resident mannosyltransferases, and thus Pmr1 is involved in the synthesis of both
- and
-linked mannans. Since we currently have limited information about the genetic network behind the
protein mannosylation machinery, we disrupted
and
in this organism. The
Δ and
Δ mutants showed increased doubling times, aberrant colony and cellular morphology, reduction in the wall mannan content, and increased susceptibility to wall perturbing agents. These changes were accompanied by increased exposure of both β1,3-glucan and chitin at the wall surface of both mutant strains. Our results showed that
-linked mannans are dispensable for cytokine production by human mononuclear cells, but
-linked mannans and β1,3-glucan are key ligands to trigger cytokine production in a co-stimulatory pathway involving dectin-1 and mannose receptor. Moreover, we found that the
-linked mannan core found on the surface of
Δ null mutant was capable of inducing cytokine production; and that a mannan-independent pathway for IL-10 production is present in the
-mononuclear cell interaction. Both mutant strains showed virulence attenuation in the
and the mouse model of systemic candidiasis. Therefore, mannans are relevant for cell wall composition and organization, and for the
-host interaction.
is one of the etiological agents of sporotrichosis, a cutaneous and subcutaneous infection distributed worldwide. Like other medically relevant fungi, its cell wall is a molecular scaffold to display ...virulence factors, such as protective pigments, hydrolytic enzymes, and adhesins. Cell wall proteins with adhesive properties have been previously reported, but only a handful of them have been identified and characterized. One of them is Gp70, an abundant cell wall protein mainly found on the surface of yeast-like cells. Since the protein also has a role in the activity of 3-carboxy-
,
-muconate cyclase and its abundance is low in highly virulent strains, its role in the
-host interaction remains unclear. Here, a set of
-silenced strains was generated, and the molecular and phenotypical characterization was performed. The results showed that mutants with high silencing levels showed a significant reduction in the adhesion to laminin and fibrinogen, enzyme activity, and defects in the cell wall composition, which included reduced mannose, rhamnose, and protein content, accompanied by an increment in β-1,3-glucans levels. The cell wall
-linked glycan content was significantly reduced. These strains induced poor TNFα and IL-6 levels when interacting with human peripheral blood mononuclear cells in a dectin-1-, TLR2-, and TLR4-dependent stimulation. The IL-1β and IL-10 levels were significantly higher and were stimulated via dectin-1. Phagocytosis and stimulation of neutrophil extracellular traps by human granulocytes were increased in highly
-silenced strains. Furthermore, these mutants showed virulence attenuation in the invertebrate model
. Our results demonstrate that Gp70 is a versatile protein with adhesin properties, is responsible for the activity of 3-carboxy-
,
-muconate cyclase, and is relevant for the
-host interaction.
Pyrophosphatases (PPases) are enzymes that catalyze the hydrolysis of pyrophosphate (PPi), a byproduct of the synthesis and degradation of diverse biomolecules. The accumulation of PPi in the cell ...can result in cell death. Although the substrate is the same, there are variations in the catalysis and features of these enzymes. Two enzyme forms have been identified in bacteria: cytoplasmic or soluble pyrophosphatases and membrane-bound pyrophosphatases, which play major roles in cell bioenergetics. In eukaryotic cells, cytoplasmic enzymes are the predominant form of PPases (c-PPases), while membrane enzymes (m-PPases) are found only in protists and plants. The study of bacterial cytoplasmic and membrane-bound pyrophosphatases has slowed in recent years. These enzymes are central to cell metabolism and physiology since phospholipid and nucleic acid synthesis release important amounts of PPi that must be removed to allow biosynthesis to continue. In this review, two aims were pursued: first, to provide insight into the structural features of PPases known to date and that are well characterized, and to provide examples of enzymes with novel features. Second, the scientific community should continue studying these enzymes because they have many biotechnological applications. Additionally, in this review, we provide evidence that there are m-PPases present in fungi; to date, no examples have been characterized. Therefore, the diversity of PPase enzymes is still a fruitful field of research. Additionally, we focused on the roles of H + /Na + pumps and m-PPases in cell bioenergetics. Finally, we provide some examples of the applications of these enzymes in molecular biology and biotechnology, especially in plants. This review is valuable for professionals in the biochemistry field of protein structure–function relationships and experts in other fields, such as chemistry, nanotechnology, and plant sciences.
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