Characterization of Cryptococcus neoformans isolated from urban environmental sources in Goiânia, Goiás State, Brazil

Cryptococcus neoformans is an opportunistic fungal pathogen that causes meningoencephalitis as the most frequent clinical presentation in immunocompromised patients, mainly in people infected by HIV. This fungus is an environmental encapsulated yeast, commonly found in soil enriched with avian droppings and plant material. A total of 290 samples of pigeon and the other avian droppings, soil, ornamental trees and vegetable material associated with Eucalyptus trees were collected to study environmental sources of Cryptococcus species in Goiânia, Goiás State. The determination of varieties, serotypes and the susceptibility in vitro to fluconazole, itraconazole and amphotericin B of C. neoformans isolates were performed. C. neoformans var. grubii (serotype A) was found in 20.3% (36/177) of pigeon dropping samples and in 14.3% (5/35) of samples of Eucalyptus. None of the environmental isolates of C. neoformans showed in vitro resistance to three antifungal agents. The knowledge of major route for human cryptococcal infection (inhalation of infectious particles from saprophytic sources) and a total of 60 C. neoformans isolates obtained from AIDS patients with cryptococcal meningitis between October 2001 and April 2002 justify the study of the habitats of these yeasts as probable sources of cryptococcosis in this city.

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The characterization of endosomal insulin degradation intermediates and their sequence of production

Biochemical Journal ◽

10.1042/bj3200947 ◽

1996 ◽

Vol 320 (3) ◽

pp. 947-956 ◽

Cited By ~ 21

Author(s):

Paul J. SEABRIGHT ◽

Geoffrey D. SMITH

Keyword(s):

Aminopeptidase Activity ◽

Insulin Degradation ◽

Endosomal Membrane ◽

Centre Region ◽

Major Route ◽

A Chain ◽

Degradation Intermediates

Insulin degradation within isolated rat liver endosomes was studied in vitro with the aid of three 125I-insulin isomers specifically labelled at tyrosine (A14, B16 and B26). Chloroquine and 1,10-phenanthroline were used to minimize insulin proteolysis during endosome preparation, whereas the manipulation of endosomal processing of insulin in vitro by Co2+ ions (to activate) and 1,10-phenanthroline (to inhibit) permitted the study of degradation intermediates and their time-dependent production. Structural and kinetic analysis of intermediates isolated from both intra- and extra-endosomal compartments allowed the determination of major cleavage sites and the probable sequence of proteolytic events. It was found that 125I-tyrosine is the ultimate labelled degradation product of all iodo-insulin isomers, suggesting that endosomal proteases are able to degrade insulin to the level of its constituent amino acids. 125I-tyrosine was also the only radiolabelled product able to cross the endosomal membrane. Intra-endosomal insulin degradation proceeds via two inter-related cleavage routes after metalloendoprotease cleavage of the B-chain. One pathway results from an initial cleavage in the centre region of the B-chain (B7–19), probably at B14-15, whereas the major route results from a cleavage at B24-25. B24-25 cleavage removes the B-chain C-terminal hexapeptide (B25–30), which is subsequently cleaved by an aminopeptidase activity to produce first the pentapeptide B26–30 and then 125I-tyrosine. The isolation of intact radiolabelled A-chain from the degradation of 125I-[A14]-insulin suggests that further degradation of proteolytic intermediates containing cleaved B-chain proceeds via interchain disulphide reduction. The A-chain is then processed by several cleavages, one of which occurs at A13-14.

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Characterization of the Serum a1-Antitripsine Level in Primary Spontaneous Pneumotorax Patients

Revista de Chimie ◽

10.37358/rc.18.9.6584 ◽

2018 ◽

Vol 69 (9) ◽

pp. 2591-2593

Author(s):

Cristina Grigorescu ◽

Liviu Ciprian Gavril ◽

Laura Gavril ◽

Tiberiu Lunguleac ◽

Bogdan Mihnea Ciuntu ◽

...

Keyword(s):

Serum Level ◽

Pulmonary Emphysema ◽

Spontaneous Pneumothorax ◽

Antitrypsin Deficiency ◽

Alpha 1 Antitrypsin Deficiency ◽

Alpha 1 Antitrypsin ◽

Determining Factor

Diagnosis of primary or idiopathic spontaneous pneumothorax is one of exclusion, and in fact defines an entity that may have a difficult or impossible cause to be highlighted by current means, we consider it appropriate to study these etiopathogenic aspects. There is a definite association between alpha-1 antitrypsin deficiency and pulmonary emphysema and indirect spontaneous pneumothorax secondary to an emphysematous pulmonary lesion. Dose of alpha-1 antitrypsin is an immunoturbinimetric method for in vitro determination of alpha-1 antitrypsin in human serum and plasma. This product is calibrated to be used for the Daytona RX analyzer. The serum level of alpha-1-antitrypsin is not a determining factor in the postoperative evolution characterized by the interval until air loss disappears, but certainly exerts some influence, the exact level of which remains to be determined.

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Antifungal activity of dendritic cell lysosomal proteins against Cryptococcus neoformans

Scientific Reports ◽

10.1038/s41598-021-92991-6 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Benjamin N. Nelson ◽

Savannah G. Beakley ◽

Sierra Posey ◽

Brittney Conn ◽

Emma Maritz ◽

...

Keyword(s):

Antifungal Activity ◽

Cryptococcus Neoformans ◽

Mammalian Cells ◽

Cysteine Proteases ◽

Dependent Manner ◽

Life Threatening ◽

Opportunistic Fungal Pathogen ◽

Dose Dependent ◽

Lysosomal Proteins

AbstractCryptococcal meningitis is a life-threatening disease among immune compromised individuals that is caused by the opportunistic fungal pathogen Cryptococcus neoformans. Previous studies have shown that the fungus is phagocytosed by dendritic cells (DCs) and trafficked to the lysosome where it is killed by both oxidative and non-oxidative mechanisms. While certain molecules from the lysosome are known to kill or inhibit the growth of C. neoformans, the lysosome is an organelle containing many different proteins and enzymes that are designed to degrade phagocytosed material. We hypothesized that multiple lysosomal components, including cysteine proteases and antimicrobial peptides, could inhibit the growth of C. neoformans. Our study identified the contents of the DC lysosome and examined the anti-cryptococcal properties of different proteins found within the lysosome. Results showed several DC lysosomal proteins affected the growth of C. neoformans in vitro. The proteins that killed or inhibited the fungus did so in a dose-dependent manner. Furthermore, the concentration of protein needed for cryptococcal inhibition was found to be non-cytotoxic to mammalian cells. These data show that many DC lysosomal proteins have antifungal activity and have potential as immune-based therapeutics.

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DAP12 Inhibits Pulmonary Immune Responses to Cryptococcus neoformans

Infection and Immunity ◽

10.1128/iai.00222-16 ◽

2016 ◽

Vol 84 (6) ◽

pp. 1879-1886 ◽

Cited By ~ 5

Author(s):

Lena J. Heung ◽

Tobias M. Hohl

Keyword(s):

Immune Response ◽

Nk Cells ◽

Cryptococcus Neoformans ◽

Molecular Mechanisms ◽

Content Type ◽

Effector Cells ◽

Opportunistic Fungal Pathogen ◽

Efficient Uptake ◽

Bacteria And Fungi

Cryptococcus neoformansis an opportunistic fungal pathogen that is inhaled into the lungs and can lead to life-threatening meningoencephalitis in immunocompromised patients. Currently, the molecular mechanisms that regulate the mammalian immune response to respiratory cryptococcal challenge remain poorly defined. DAP12, a signaling adapter for multiple pattern recognition receptors in myeloid and natural killer (NK) cells, has been shown to play both activating and inhibitory roles during lung infections by different bacteria and fungi. In this study, we demonstrate that DAP12 plays an important inhibitory role in the immune response toC. neoformans. Infectious outcomes in DAP12−/−mice, including survival and lung fungal burden, are significantly improved compared to those in C57BL/6 wild-type (WT) mice. We find that eosinophils and macrophages are decreased while NK cells are increased in the lungs of infected DAP12−/−mice. In contrast to WT NK cells, DAP12−/−NK cells are able to repressC. neoformansgrowthin vitro. Additionally, DAP12−/−macrophages are more highly activated than WT macrophages, with increased production of tumor necrosis factor (TNF) and CCL5/RANTES and more efficient uptake and killing ofC. neoformans. These findings suggest that DAP12 acts as a brake on the pulmonary immune response toC. neoformansby promoting pulmonary eosinophilia and by inhibiting the activation and antifungal activities of effector cells, including NK cells and macrophages.

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Characterization of the Urease Operon of Brucella abortus and Assessment of Its Role in Virulence of the Bacterium

Infection and Immunity ◽

10.1128/iai.01244-06 ◽

2006 ◽

Vol 75 (2) ◽

pp. 774-780 ◽

Cited By ~ 73

Author(s):

Félix J. Sangari ◽

Asunción Seoane ◽

María Cruz Rodríguez ◽

Jesús Agüero ◽

Juan M. García Lobo

Keyword(s):

Brucella Abortus ◽

Urease Activity ◽

Strong Acid ◽

Oral Route ◽

Open Reading Frames ◽

Human Brucellosis ◽

Major Route

ABSTRACT Most members of the genus Brucella show strong urease activity. However, the role of this enzyme in the pathogenesis of Brucella infections is poorly understood. We isolated several Tn5 insertion mutants deficient in urease activity from Brucella abortus strain 2308. The mutations of most of these mutants mapped to a 5.7-kbp DNA region essential for urease activity. Sequencing of this region, designated ure1, revealed the presence of seven open reading frames corresponding to the urease structural proteins (UreA, UreB, and UreC) and the accessory proteins (UreD, UreE, UreF, and UreG). In addition to the urease genes, another gene (cobT) was identified, and inactivation of this gene affected urease activity in Brucella. Subsequent analysis of the previously described sequences of the genomes of Brucella spp. revealed the presence of a second urease cluster, ure2, in all them. The ure2 locus was apparently inactive in B. abortus 2308. Urease-deficient mutants were used to evaluate the role of urease in Brucella pathogenesis. The urease-producing strains were found to be resistant in vitro to strong acid conditions in the presence of urea, while urease-negative mutants were susceptible to acid treatment. Similarly, the urease-negative mutants were killed more efficiently than the urease-producing strains during transit through the stomach. These results suggested that urease protects brucellae during their passage through the stomach when the bacteria are acquired by the oral route, which is the major route of infection in human brucellosis.

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In vitro determination of optimal antifungal combinations against Cryptococcus neoformans and Candida albicans

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.39.11.2459 ◽

1995 ◽

Vol 39 (11) ◽

pp. 2459-2465 ◽

Cited By ~ 47

Author(s):

M. A. Ghannoum ◽

Y. Fu ◽

A. S. Ibrahim ◽

L. A. Mortara ◽

M. C. Shafiq ◽

...

Keyword(s):

Candida Albicans ◽

Cryptococcus Neoformans

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Characterization of a New Chitosanase from a Marine Bacillus sp. and the Anti-Oxidant Activity of Its Hydrolysate

Marine Drugs ◽

10.3390/md18020126 ◽

2020 ◽

Vol 18 (2) ◽

pp. 126

Author(s):

Chunrui Ma ◽

Xiao Li ◽

Kun Yang ◽

Shangyong Li

Keyword(s):

Radical Scavenging ◽

Maximal Activity ◽

Hydroxyl Groups ◽

Bacillus Sp ◽

Low Molecular Weight Chitosan ◽

Anti Oxidant

Chitooligosaccharide (COS) has been recognized to exhibit efficient anti-oxidant activity. Enzymatic hydrolysis using chitosanases can retain all the amino and hydroxyl groups of chitosan, which are necessary for its activity. In this study, a new chitosanase encoding gene, csnQ, was cloned from the marine Bacillus sp. Q1098 and expressed in Escherichia coli. The recombinant chitosanase, CsnQ, showed maximal activity at pH 5.31 and 60 °C. Determination of CsnQ pH-stability showed that CsnQ could retain more than 50% of its activity over a wide pH, from 3.60 to 9.80. CsnQ is an endo-type chitosanase, yielding chitodisaccharide as the main product. Additionally, in vitro and in vivo analyses indicated that chitodisaccharide possesses much more effective anti-oxidant activity than glucosamine and low molecular weight chitosan (LMW-CS) (~5 kDa). Notably, to our knowledge, this is the first evidence that chitodisaccharide is the minimal COS fragment required for free radical scavenging.

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Substrate Proteins Take Shape at an Improved Bacterial Translocon

Journal of Bacteriology ◽

10.1128/jb.00618-18 ◽

2018 ◽

Vol 201 (1) ◽

Cited By ~ 2

Author(s):

Donald Oliver

Keyword(s):

Protein Transport ◽

Protein Translocation ◽

Membrane Vesicles ◽

Transport Models ◽

Content Type ◽

Rate Limiting ◽

Substrate Proteins

ABSTRACTCharacterization of Sec-dependent bacterial protein transport has often relied on anin vitroprotein translocation system comprised in part ofEscherichia coliinverted inner membrane vesicles or, more recently, purified SecYEG translocons reconstituted into liposomes using mostly a single substrate (proOmpA). A paper published in this issue (P. Bariya and L. Randall, J Bacteriol 201:e00493-18, 2019, https://doi.org/10.1128/JB.00493-18) finds that inclusion of SecA protein during SecYEG proteoliposome reconstitution dramatically improves the number of active translocons. This experimentally useful and intriguing result that may arise from SecA membrane integration properties is discussed here. Furthermore, determination of the rate-limiting transport step for nine different substrates implicates the mature region distal to the signal peptide in the observed rate constant differences, indicating that more nuanced transport models that respond to differences in protein sequence and structure are needed.

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