The Genetics and Biochemistry of Cell Wall Structure and Synthesis in Neurospora crassa, a Model Filamentous Fungus.
Patel PK1, Free SJ1.
Author information
1
Department of Biological Sciences, SUNY University at Buffalo, Buffalo, NY, United States.
Abstract
This review discusses the wealth of information available for the N. crassa cell wall. The basic organization and structure of the cell wall is presented and how the wall changes during the N. crassa life cycle is discussed. Over forty cell wall glycoproteins have been identified by proteomic analyses. Genetic and biochemical studies have identified many of the key enzymes needed for cell wall biogenesis, and the roles these enzymes play in cell wall biogenesis are discussed. The review includes a discussion of how the major cell wall components (chitin, β-1,3-glucan, mixed β-1,3-/ β-1,4- glucans, glycoproteins, and melanin) are synthesized and incorporated into the cell wall. We present a four-step model for how cell wall glycoproteins are covalently incorporated into the cell wall. In N. crassa, the covalent incorporation of cell wall glycoproteins into the wall occurs through a glycosidic linkage between lichenin (a mixed β-1,3-/β-1,4- glucan) and a "processed" galactomannan that has been attached to the glycoprotein N-linked oligosaccharides. The first step is the addition of the galactomannan to the N-linked oligosaccharide. Mutants affected in galactomannan formation are unable to incorporate glycoproteins into their cell walls. The second step is carried out by the enzymes from the GH76 family of α-1,6-mannanases, which cleave the galactomannan to generate a processed galactomannan. The model suggests that the third and fourth steps are carried out by members of the GH72 family of glucanosyltransferases. In the third step the glucanosyltransferases cleave lichenin and generate enzyme/substrate intermediates in which the lichenin is covalently attached to the active site of the glucanosyltransferases. In the final step, the glucanosyltransferases attach the lichenin onto the processed galactomannans, which creates new glycosidic bonds and effectively incorporates the glycoproteins into the cross-linked cell wall glucan/chitin matrix.

Copyright © 2019 Patel and Free.

KEYWORDS:
Neurospora; cell wall; filamentous fungi; galactomannan; glucan; glucanosyltransferase; mannanase; melanin

PMID: 31649638 PMCID: PMC6796803 DOI: 10.3389/fmicb.2019.02294
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22.
Front Microbiol. 2019 Oct 4;10:2291. doi: 10.3389/fmicb.2019.02291. eCollection 2019.
Reduced Gut Microbiome Diversity and Metabolome Differences in Rhinoceros Species at Risk for Iron Overload Disorder.
Roth TL1, Switzer A2,3, Watanabe-Chailland M4, Bik EM2,3, Relman DA2,3,5, Romick-Rosendale LE4, Ollberding NJ6,7.
Author information
1
Center for Conservation and Research of Endangered Wildlife, Cincinnati Zoo & Botanical Garden, Cincinnati, OH, United States.
2
Department of Medicine, School of Medicine, Stanford University, Stanford, CA, United States.
3
Department of Microbiology and Immunology, School of Medicine, Stanford University, Stanford, CA, United States.
4
Division of Pathology and Laboratory Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.
5
Infectious Diseases Section, VA Palo Alto Health Care System, Palo Alto, CA, United States.
6
Division of Biostatistics and Epidemiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.
7
Department of Pediatrics, College of Medicine, University of Cincinnati, Cincinnati, OH, United States.
Abstract
Iron overload disorder (IOD) affects many wildlife species cared for ex situ. Two of the four rhinoceros species in human care, Sumatran rhinoceros (Dicerorhinus sumatrensis) and black rhinoceros (Diceros bicornis), are susceptible, whereas the other two, white rhinoceros (Ceratotherium simum) and greater one-horned (GOH) rhinoceros (Rhinoceros unicornis), are relatively resistant to IOD. Complex interrelationships exist between mammalian hosts, their indigenous gut microbiota, metabolome, physical condition, and iron availability. The goal of this study was to gain insight into these relationships within the family Rhinocerotidae. Specific objectives were to (1) characterize the gut microbiome and metabolome of four rhinoceros species; (2) compare the microbiome and metabolome of IOD-susceptible and IOD-resistant rhinoceros species; and (3) identify variation in the microbiome and metabolome associated with compromised health or disease in IOD-susceptible rhinoceroses. Fecal samples were collected from 31 rhinoceroses (Sumatran rhinoceros, n = 3; black rhinoceros, n = 6; GOH rhinoceros, n = 9; white rhinoceros, n = 13) located at five facilities, and matched fecal aliquots were processed for microbiome and metabolome analyses using 16S rRNA gene sequencing and nuclear magnetic resonance spectroscopy, respectively. Despite the phylogenetic disparity and dissimilar zoo diets of the hosts, the structure of the fecal microbiota of the two IOD-susceptible rhinoceros species were more closely related to each other than to those of the two IOD-resistant species (Bray-Curtis dissimilarity; IOD-susceptible vs. IOD-resistant p-value < 0.001). In addition, IOD-susceptible rhinoceroses exhibited less microbial diversity than their IOD-resistant relatives (Shannon diversity; p-value < 0.001) which could have health implications. Of note, the black rhinoceros was distinct among the four rhinoceros species with the most divergent fecal metabolome; interestingly, it contained higher concentrations of short chain fatty acids. Neither age nor sex were associated with differences in microbial community composition (p = 0.253 and 0.488, respectively) or fecal metabolomic profile (p = 0.634 and 0.332, respectively). Differences in the distal gut microbiomes between IOD-resistant and IOD-susceptible rhinoceroses support hypotheses that gut microbes play a role in host iron acquisition, and further studies and experiments to test these hypotheses are warranted.

Copyright © 2019 Roth, Switzer, Watanabe-Chailland, Bik, Relman, Romick-Rosendale and Ollberding.

KEYWORDS:
Sumatran rhinoceros; black rhinoceros; disease susceptibility; iron overload; metabolome; microbial diversity; microbiome; rhinoceros

PMID: 31649637 PMCID: PMC6792462 DOI: 10.3389/fmicb.2019.02291
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23.
Front Microbiol. 2019 Oct 8;10:2289. doi: 10.3389/fmicb.2019.02289. eCollection 2019.
Robust Approaches for the Production of Active Ingredient and Drug Product for Human Phage Therapy.
Mutti M1, Corsini L1.
Author information
1
PhagoMed Biopharma GmbH, Vienna, Austria.
Abstract
To be successful, academic and commercial efforts to reintroduce phage therapy must ensure that only safe and efficacious products are used to treat patients. This raises a number of manufacturing, formulation, and delivery challenges. Since phages are biologics, robust manufacturing processes will be crucial to avoid unwanted variability in each step of the process. The quality standards themselves need to be developed, as patients are currently being treated with phages produced under quality standards ranging from cGMP for clinical trials in EMA and FDA regulated environments to no standards at all in some last resort treatments. In this short review, we will systematically review the literature covering technical issues and approaches to increase robustness at every step of the production process: the identity of the phage and bacterial production strains, the fermentation process and purification, the formulation of the drug product, the quality controls and the documentation standards themselves. We conclude that it is possible to control cost at the same time, which is critical to re-introduce phage therapy to western medicine.

Copyright © 2019 Mutti and Corsini.

KEYWORDS:
PhagoMed; antibiotic resistance; bacteriophages; phage purification; phage therapy; quality by design

PMID: 31649636 PMCID: PMC6791927 DOI: 10.3389/fmicb.2019.02289
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Select item 31649635
24.
Front Microbiol. 2019 Oct 9;10:2288. doi: 10.3389/fmicb.2019.02288. eCollection 2019.
Co-resistance to Amoxicillin and Tetracycline as an Indicator of Multidrug Resistance in Escherichia coli Isolates From Animals.
Bourély C1,2,3, Cazeau G2, Jarrige N2, Jouy E4, Haenni M5, Lupo A5, Madec JY5, Leblond A3, Gay E2.
Author information
1
École Nationale des Services Vétérinaires, ENSV, VetAgro Sup, Marcy l'Étoile, France.
2
ANSES, Laboratoire de Lyon, Unité Épidémiologie et Appui à la Surveillance, Université de Lyon, Lyon, France.
3
EPIA, UMR 0346, Epidémiologie des Maladies Animales et Zoonotiques, INRA, VetAgro Sup, University of Lyon, Marcy l'Étoile, France.
4
Laboratoire de Ploufragan-Plouzané-Niort, ANSES, Unité Mycoplasmologie Bactériologie Antibiorésistance, Université Bretagne Loire, Technopôle Saint-Brieuc Armor, Ploufragan, France.
5
ANSES, Laboratoire de Lyon, Unité Antibiorésistance et Virulence Bactériennes, Université de Lyon, Lyon, France.
Abstract
OBJECTIVES:
To examine the relevance of co-resistance to amoxicillin and tetracycline as an indicator of multidrug resistance (MDR) in animal health.

METHODS:
Escherichia coli isolates collected between 2012 and 2016 by the French surveillance network for antimicrobial resistance in diseased animals (RESAPATH) were analyzed. The proportions of MDR isolates and the proportions of isolates presenting co-resistance to amoxicillin and tetracycline were calculated for seven animal species (cattle, horse, dog, swine, poultry, duck, and turkey). The degree of agreement between these two proportions was estimated by calculating the kappa value.

RESULTS:
In total, 55,904 isolates were analyzed. MDR proportions were variable among animal species, ranging from 21.9% [20.2; 23.7] in horses to 56.0% [55.4; 56.7] in cattle. A similar situation was observed for proportions of isolates with co-resistance to amoxicillin and tetracycline, with the highest value for cattle 65.0% [64.3; 65.6]. This co-resistance was also most often associated with resistance to other antibiotics, regardless of the animal species considered. Comparative analysis showed substantial agreement between MDR and this co-resistance, with a kappa value of 0.75, all animal species considered.

CONCLUSION:
Given the widespread use of penicillins and tetracyclines in animal health, co-resistance to amoxicillin and tetracycline could be an efficient indicator of MDR in E. coli isolates. Based on a specific resistance profile and not an arbitrary number of resistances compared with MDR, this potential indicator is also precise, convenient and suitable for routine use.

Copyright © 2019 Bourély, Cazeau, Jarrige, Jouy, Haenni, Lupo, Madec, Leblond and Gay.

KEYWORDS:
E. coli; RESAPATH; animal health; antimicrobial resistance; multidrug resistance

PMID: 31649635 PMCID: PMC6794424 DOI: 10.3389/fmicb.2019.02288
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25.
Front Microbiol. 2019 Oct 8;10:2286. doi: 10.3389/fmicb.2019.02286. eCollection 2019.
Yeasts of Burden: Exploring the Mycobiome-Bacteriome of the Piglet GI Tract.
Arfken AM1, Frey JF1, Ramsay TG1, Summers KL1.
Author information
1
Animal Biosciences and Biotechnology Laboratory, United States Department of Agriculture-Agricultural Research Service, Beltsville, MD, United States.
Abstract
Interactions between the bacteria and fungi in the gut microbiome can result in altered nutrition, pathogenicity of infection, and host development, making them a crucial component in host health. Associations between the mycobiome and bacteriome in the piglet gut, in the context of weaning, remain unknown. Weaning is a time of significant stress, dietary changes, microbial alterations, and a predisposition to infection. The loss of animal health and growth makes potential microbial interventions of interest to the swine industry. Recent studies have demonstrated the diversity and development of the microbiome in the gastrointestinal (GI) tract of piglets during weaning, resulting from the dietary and physiological changes. Despite these advances, the role of the mycobiota in piglet health and its contribution to overall microbiome development remains mostly unknown. In this study we investigated the bacteriome and the mycobiome after weaning in the GI tract organs and feces from 35-day old piglets. Following weaning, the α-diversity and amplicon sequence variants (ASVs) counts of the bacteriome increased, proximally to distally, from the stomach to the feces along the GI tract, while the mycobiome α-diversity and ASV counts were highest in the porcine stomach. β-diversity analyses show distinct clusters based on organ type in the bacteriome and mycobiome, but dispersion remained relatively constant in the mycobiome between organ/fecal sites. Bacteroidetes, Firmicutes, and Epsilonbacteraeota were the most abundant bacterial phyla present in the GI tract and feces based on mean taxonomic composition with high variation of composition found in the stomach. In the mycobiome, the dominant phyla were Ascomycota and Basidiomycota, and the stomach mycobiome did not demonstrate the same high level of variation observed in the bacteriome. Potential interactions between genera were found in the lower piglet GI bacteriome and mycobiome with positive correlations found between the fungus, Kazachstania, and several bacterial species, including Lactobacillus. Aspergillus demonstrated negative correlations with the short chain fatty acid-producing bacteria Butyricoccus, Subdoligranulum, and Fusicatenibacter. This study demonstrates the distinct colonization dynamics between fungi and bacteria in the GI tract and feces of piglets directly following weaning and the potential interactions of these microbes in the porcine gut ecosystem.

Copyright © 2019 Arfken, Frey, Ramsay and Summers.

KEYWORDS:
bacteriome; microbiome; mycobiome; piglet; swine; weaning

PMID: 31649634 PMCID: PMC6792466 DOI: 10.3389/fmicb.2019.02286
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26.
Front Microbiol. 2019 Oct 9;10:2281. doi: 10.3389/fmicb.2019.02281. eCollection 2019.
Identifying Suitable Listeria innocua Strains as Surrogates for Listeria monocytogenes for Horticultural Products.
Mohan V1, Wibisono R1, de Hoop L1, Summers G1, Fletcher GC1.
Author information
1
Food Safety and Preservation Team, The New Zealand Institute for Plant & Food Research Limited, Auckland, New Zealand.
Abstract
A laboratory-based study testing 9 Listeria innocua strains independently and a cocktail of 11 Listeria monocytogenes strains was carried out. The aim was to identify suitable L. innocua strain(s) to model L. monocytogenes in inactivation experiments. Three separate inactivation procedures and a hurdle combination of the three were employed: thermal inactivation (55°C), UV-C irradiation (245 nm), and chemical sanitizer (TsunamiTM 100, a mixture of acetic acid, peroxyacetic acid, and hydrogen peroxide). The responses were strain dependent in the case of L. innocua with different strains responding differently to different regimes and L. innocua isolates generally responded differently to the L. monocytogenes cocktail. In the thermal inactivation treatment, inactivation of all strains including the L. monocytogenes cocktail plateaued after 120 min. In the case of chemical sanitizer, inactivation could be achieved at concentrations of 10 and 20 ppm with inactivation increasing with contact time up to 8 min, beyond which there was no significant benefit. All L. innocua strains except PFR16D08 were more sensitive than the L. monocytogenes cocktail to the hurdle treatment. PFR16D08 almost matched the resistance of the L. monocytogenes cocktail but was much more resistant to the individual treatments. A cocktail of two L. innocua strains (PFR 05A07 and PFR 05A10) had the closest responses to the hurdle treatment to those of the L. monocytogenes cocktail and is therefore recommended for hurdle experiments.

Copyright © 2019 Mohan, Wibisono, de Hoop, Summers and Fletcher.

KEYWORDS:
Listeria (L.) monocytogenes; Listeria innocua; UV-C; heat; sanitizer

PMID: 31649633 PMCID: PMC6794387 DOI: 10.3389/fmicb.2019.02281
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27.
Front Microbiol. 2019 Oct 9;10:2277. doi: 10.3389/fmicb.2019.02277. eCollection 2019.
Plant Growth and Soil Microbial Impacts of Enhancing Licorice With Inoculating Dark Septate Endophytes Under Drought Stress.
He C1, Wang W1,2, Hou J2.
Author information
1
Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
2
School of Chinese Pharmacy, Beijing University of Chinese Medicine, Beijing, China.
Abstract
This study mainly aimed to investigate the effects of dark septate endophytes (DSE) (Acrocalymma vagum, Paraboeremia putaminum, and Fusarium acuminatum) on the growth and microbial community composition in the rhizosphere soil of a medicinal plant, licorice (Glycyrrhiza uralensis), grown in the non-sterile soil under drought stress. The results showed that three DSE strains could effectively colonize the plant roots and form a strain-dependent symbiosis with licorice. Although drought stress declined the growth of licorice plants, these decreases were partly recovered by DSE inoculation. Specifically, the inoculation of A. vagum and P. putaminum significantly increased the biomass and glycyrrhizin content, whereas A. vagum and F. acuminatum increased glycyrrhizic acid content of host plants under drought stress. However, the inoculation of F. acuminatum showed significant negative effects on the shoot, root, and total biomass of licorice plants. In addition, the effects of DSE inoculation on the morphological, photosynthetic, and antioxidant parameters of licorice plants, and mineral nutrient and microbial community composition in the rhizosphere soil were dependent on the DSE species as well as water regime. Interestingly, DSE inoculation significantly increased AM fungi content under drought stress. In addition, DSE associated with water had a significant positive influence on soil organic matter, available phosphorus (P), AM fungi, leaf number, soluble protein, SOD activity, total root length, root branch, and glycyrrhizic acid content. Based on the results of variance partitioning analysis, 17.0, 34.0, 14.9, 40.1, 28.2, and 18.0% variations in shoot morphology, root morphology, plant biomass, active ingredient, photosynthetic parameters, and antioxidant parameters, respectively, were attributable to the presence of certain soil microorganisms. These findings suggest the possibility that DSE inoculation improved the root development and nutrient absorption of host plants, altered the soil microbiota, and might also contribute to plant growth and survival under drought conditions. As A. vagum exhibited positive effects on the plant biomass, morphological and physiological parameters, and active ingredient content in licorice plants under drought stress, it was considered to be the best fungus for licorice cultivation. These results contribute to the understanding of the ecological function of DSE fungi in dryland agriculture.

Copyright © 2019 He, Wang and Hou.

KEYWORDS:
dark septate endophytes; drought; licorice; plant performance; soil microbial community composition; symbiosis

PMID: 31649632 PMCID: PMC6794389 DOI: 10.3389/fmicb.2019.02277
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28.
Front Microbiol. 2019 Oct 9;10:2268. doi: 10.3389/fmicb.2019.02268. eCollection 2019.
Relationship of Serum Antileishmanial Antibody With Development of Visceral Leishmaniasis, Post-kala-azar Dermal Leishmaniasis and Visceral Leishmaniasis Relapse.
Mondal D1, Ghosh P1, Chowdhury R1, Halleux C2, Ruiz-Postigo JA3, Alim A1, Hossain F1, Khan MAA1, Nath R1, Duthie MS4, Kroeger A5, Matlashewski G6, Argaw D3, Olliaro P2,7.
Author information
1
Emerging Infections and Parasitology Laboratory, International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh.
2
UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR), World Health Organization, Geneva, Switzerland.
3
Department of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland.
4
Infectious Disease Research Institute, Seattle, WA, United States.
5
Centre for Medicine and Society, University Medical Center Freiburg, Freiburg im Breisgau, Germany.
6
Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada.
7
Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom.
Abstract
INTRODUCTION:
To sustain the achievement of kala-azar elimination program (KEP), early detection and treatment of the visceral leishmaniasis (VL) cases and associated modalities such as treatment failure (TF), relapse VL (RVL), and Post-kala-azar dermal leishmaniasis (PKDL) is the cornerstone. A predictive biomarker for VL development and related complications could also play a crucial role in curtailing disease incidence and transmission. Investigations to find a biomarker with prospective capabilities are, however, scarce. Using samples and known clinical outcomes generated within two previous longitudinal cohort studies, we aimed to determine if fluctuations in serum anti-rK39 antibody levels could provide such predictive value.

MATERIALS AND METHODS:
Serum samples collected at four different time points (Baseline, 12, 18, and 24 months) from 16 patients who had developed VL within the monitoring period and 15 of their asymptomatic healthy controls counterparts were investigated. To investigate potential prediction of VL related complications, serum samples of 32 PKDL, 10 RVL, 07 TF, and 38 cured VL from a single dose AmBisome trial were analyzed. Of this second panel, all patients were monitored for 5 years and sera were collected at four time points (Baseline then 1, 6, and 12 months after treatment). The level of anti-rK39 antibodies in archived samples was measured by a semi-quantitative ELISA.

RESULTS:
The mean antibody level was significantly higher in VL patients compared to their asymptomatic healthy counterparts at each time point. Likewise, we observed a trend toward elevations in antibody levels for PKDL, RVL, TF relative to the reducing levels observed in cured VL. Receiver operating characteristic (ROC) analysis found a promising predictive power of rK39 antibody levels to reveal progression from asymptomatic Leishmania donovani infection stage to VL, defined as 87.5% sensitive and 95% specific. Following treatment, rk39 antibody notably showed 100% sensitivity and 95% specificity in predicting TF.

CONCLUSION:
Our data indicate that the relative quantity of serum anti-rK39 antibody has promise within either a predictive or prognostic algorithm for VL and VL-related modalities. These could enable VL control programs to implement more effective measures to eliminate the disease. Further research is, however, imperative to standardize the rK39 antibody ELISA between sites prior to broader use.

Copyright © 2019 Mondal, Ghosh, Chowdhury, Halleux, Ruiz-Postigo, Alim, Hossain, Khan, Nath, Duthie, Kroeger, Matlashewski, Argaw and Olliaro.

KEYWORDS:
ELISA; Post-kala-azar dermal leishmaniasis (PKDL); predictive biomarker; rK39 antibody; relapse VL (RVL); treatment failure (TF); visceral leishmaniasis (VL)

PMID: 31649631 PMCID: PMC6795025 DOI: 10.3389/fmicb.2019.02268
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29.
Front Microbiol. 2019 Oct 9;10:2264. doi: 10.3389/fmicb.2019.02264. eCollection 2019.
Association of TREM-1, IL-1β, IL-33/ST2, and TLR Expressions With the Pathogenesis of Ocular Toxoplasmosis in Mouse Models on Different Genetic Backgrounds.
Zhang Y1,2, He J1,2,3, Zheng H1,2, Huang S4, Lu F1,2.
Author information
1
Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.
2
Key Laboratory of Tropical Disease Control of Ministry of Education, Sun Yat-sen University, Guangzhou, China.
3
Public Experimental Teaching Center, Sun Yat-sen University, Guangzhou, China.
4
School of Stomatology, Jinan University, Guangzhou, China.
Abstract
Ocular toxoplasmosis (OT) is one of the most common causes of posterior uveitis. The signaling of triggering receptor expressed on myeloid cells (TREM)-1 amplifies inflammation, whereas TREM-2 signaling is anti-inflammatory. IL-1β is a major driver of inflammation during infection. Toll-like receptors (TLRs) play important roles in protective immune response during Toxoplasma gondii infection, and interleukin (IL)-33 receptor (T1/ST2) signaling prevents toxoplasmic encephalitis in mice. However, the pathogenic mechanisms of OT are not yet well elucidated. To investigate the role of TREM-1, TREM-2, IL-1β, IL-33/ST2, and TLRs in OT of susceptible C57BL/6 (B6) and resistant BALB/c mice, both strains of mice were intravitreally infected with 500 tachyzoites of the RH strain of T. gondii. Histopathological analysis showed that T. gondii-infected B6 mice had more severe ocular damage observed by light microscopy, higher number of neutrophil elastase-positive cells in the eyes detected by immunohistochemical staining, more T. gondii tachyzoites in the eyes observed by transmission electron microscopy, and higher mRNA expression levels of tachyzoite-specific surface antigen 1 detected by quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) in comparison of T. gondii-infected BALB/c mice. Detected by using qRT-PCR, the mRNA expression levels of TREM-1, IL-1β, IL-33, ST2, TLR11, TLR12, and TLR13 were significantly higher in the eyes of T. gondii-infected B6 mice than those of T. gondii-infected BALB/c mice, whereas the mRNA expression levels of TLR3 and TLR9 were significantly higher in the eyes of T. gondii-infected BALB/c mice than those of T. gondii-infected B6 mice. Correlation analysis showed that significant positive correlations existed between TREM-1 and IL-1β/IL-33/ST2/TLR9/TLR11 in the eyes of B6 mice and existed between TREM-1 and IL-33/ST2/TLR3/TLR9/TLR13 in the eyes of BALB/c mice after ocular T. gondii infection. Our data revealed that, compared with T. gondii-resistant BALB/c mice, ocular T. gondii infection can stimulate higher production of TREM-1, IL-33, ST2, TLR11, TLR12, and TLR13 in the eyes of T. gondii-susceptible B6 mice, however, whether those lead to more severe ocular pathology in the susceptible B6 mice remain to be further studied.

Copyright © 2019 Zhang, He, Zheng, Huang and Lu.

KEYWORDS:
BALB/c mice; C57BL/6 mice; IL-1β; IL-33/ST2; TLRs; TREM-1; neutrophils; ocular toxoplasmosis

PMID: 31649630 PMCID: PMC6794992 DOI: 10.3389/fmicb.2019.02264
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30.
Front Microbiol. 2019 Oct 9;10:2262. doi: 10.3389/fmicb.2019.02262. eCollection 2019.
Similar Shift Patterns in Gut Bacterial and Fungal Communities Across the Life Stages of Bactrocera minax Larvae From Two Field Populations.
Yao Z1, Ma Q1, Cai Z1, Raza MF1, Bai S1, Wang Y1, Zhang P1, Ma H1, Zhang H1.
Author information
1
State Key Laboratory of Agricultural Microbiology, Institute of Urban and Horticultural Entomology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China.
Abstract
Bactrocera minax (Enderlein) (Diptera: Tephritidae) is an oligophagous insect pest that damages citrus fruit, especially in China. Due to larvae living within a highly septic environment, a wide variety of microorganisms exist in the larval gut of B. minax. However, a systematic study of the intestinal microbiota of this harmful insect pest is still lacking. Here, we comprehensively investigated the larval gut microbiota of B. minax in two field populations from Zigui (developed in orange) and Danjiangkou (developed in mandarin orange). We observed a dominance of Proteobacteria and Firmicutes in these bacterial communities, and Enterobacteriaceae was the predominant family throughout the larval stage. However, most of the identified fungal sequences were annotated as being from either Ascomycota or Basidiomycota phyla. Although there was a difference in the structure of the microbial communities between the two populations, the dynamic change patterns of most of the members of the microbiota were similar across the lifespan of larvae in both populations. The relative abundances of the Acetobacteraceae, Leuconostocaceae, and Lactobacillaceae gut bacteria as well as the Pichiaceae, Sebacinaceae, and Amanitaceae fungi increased throughout development, and these microorganisms stably resided in the larval gut. Furthermore, the dynamic changes of the functions of gut bacterial communities were inferred, and there was a significant increase in carbohydrate metabolism across the lifespan of larvae in both groups. Spearman correlation analysis showed that Acetobacteraceae, Lactobacillaceae, and Leuconostocaceae displayed a positive correlation with fructose and mannose metabolism, an important pathway of carbohydrate metabolism, highlighting the potential roles of these prevalent microbial communities in host biology.

Copyright © 2019 Yao, Ma, Cai, Raza, Bai, Wang, Zhang, Ma and Zhang.

KEYWORDS:
Bactrocera minax; bacteria; development; dynamic change; fungi

PMID: 31649629 PMCID: PMC6794421 DOI: 10.3389/fmicb.2019.02262
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31.
Front Microbiol. 2019 Oct 9;10:2261. doi: 10.3389/fmicb.2019.02261. eCollection 2019.
Microcins in Enterobacteriaceae: Peptide Antimicrobials in the Eco-Active Intestinal Chemosphere.
Baquero F1, Lanza VF2, Baquero MR3, Del Campo R1, Bravo-Vázquez DA3.
Author information
1
Department of Microbiology, Ramón y Cajal University Hospital, Ramón y Cajal Institute for Health Research (IRYCIS), Madrid, Spain.
2
Bioinformatics Unit, Ramón y Cajal University Hospital, Ramón y Cajal Institute for Health Research (IRYCIS), Madrid, Spain.
3
Department of Microbiology, Alfonso X El Sabio University, Villanueva de la Cañada, Spain.
Abstract
Microcins are low-molecular-weight, ribosomally produced, highly stable, bacterial-inhibitory molecules involved in competitive, and amensalistic interactions between Enterobacteriaceae in the intestine. These interactions take place in a highly complex chemical landscape, the intestinal eco-active chemosphere, composed of chemical substances that positively or negatively influence bacterial growth, including those originated from nutrient uptake, and those produced by the action of the human or animal host and the intestinal microbiome. The contribution of bacteria results from their effect on the host generated molecules, on food and digested food, and organic substances from microbial origin, including from bacterial degradation. Here, we comprehensively review the main chemical substances present in the human intestinal chemosphere, particularly of those having inhibitory effects on microorganisms. With this background, and focusing on Enterobacteriaceae, the most relevant human pathogens from the intestinal microbiota, the microcin's history and classification, mechanisms of action, and mechanisms involved in microcin's immunity (in microcin producers) and resistance (non-producers) are reviewed. Products from the chemosphere likely modulate the ecological effects of microcin activity. Several cross-resistance mechanisms are shared by microcins, colicins, bacteriophages, and some conventional antibiotics, which are expected to produce cross-effects. Double-microcin-producing strains (such as microcins MccM and MccH47) have been successfully used for decades in the control of pathogenic gut organisms. Microcins are associated with successful gut colonization, facilitating translocation and invasion, leading to bacteremia, and urinary tract infections. In fact, Escherichia coli strains from the more invasive phylogroups (e.g., B2) are frequently microcinogenic. A publicly accessible APD3 database http://aps.unmc.edu/AP/ shows particular genes encoding microcins in 34.1% of E. coli strains (mostly MccV, MccM, MccH47, and MccI47), and much less in Shigella and Salmonella (<2%). Some 4.65% of Klebsiella pneumoniae are microcinogenic (mostly with MccE492), and even less in Enterobacter or Citrobacter (mostly MccS). The high frequency and variety of microcins in some Enterobacteriaceae indicate key ecological functions, a notion supported by their dominance in the intestinal microbiota of biosynthetic gene clusters involved in the synthesis of post-translationally modified peptide microcins.

Copyright © 2019 Baquero, Lanza, Baquero, del Campo and Bravo-Vázquez.

KEYWORDS:
Enterobacteriaceae; bacteriocins; chemosphere; colicins; competition; microcins; molecular ecology

PMID: 31649628 PMCID: PMC6795089 DOI: 10.3389/fmicb.2019.02261
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Select item 31649627
32.
Front Microbiol. 2019 Oct 9;10:2258. doi: 10.3389/fmicb.2019.02258. eCollection 2019.
Composition and Drivers of Gut Microbial Communities in Arctic-Breeding Shorebirds.
Grond K1, Santo Domingo JW2, Lanctot RB3, Jumpponen A1, Bentzen RL4, Boldenow ML5, Brown SC6, Casler B7, Cunningham JA8, Doll AC9, Freeman S10, Hill BL5, Kendall SJ10, Kwon E11, Liebezeit JR12, Pirie-Dominix L13, Rausch J14, Sandercock BK15.
Author information
1
Division of Biology, Kansas State University, Manhattan, KS, United States.
2
U.S. Environmental Protection Agency, Cincinnati, OH, United States.
3
Migratory Bird Management, U.S. Fish & Wildlife Service, Anchorage, AK, United States.
4
Wildlife Conservation Society, Fairbanks, AK, United States.
5
Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK, United States.
6
Manomet Inc., Saxtons River, VT, United States.
7
Independent Researcher, Nehalem, OR, United States.
8
Department of Fisheries and Wildlife Sciences, University of Missouri, Columbia, MO, United States.
9
Denver Museum of Nature & Science, Denver, CO, United States.
10
Arctic National Wildlife Refuge, U.S. Fish & Wildlife Service, Fairbanks, AK, United States.
11
Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, VA, United States.
12
Audubon Society of Portland, Portland, OR, United States.
13
Environment and Climate Change Canada, Iqaluit, NU, Canada.
14
Environment and Climate Change Canada, Yellowknife, NT, Canada.
15
Department of Terrestrial Ecology, Norwegian Institute for Nature Research, Trondheim, Norway.
Abstract
Gut microbiota can have important effects on host health, but explanatory factors and pathways that determine gut microbial composition can differ among host lineages. In mammals, host phylogeny is one of the main drivers of gut microbiota, a result of vertical transfer of microbiota during birth. In birds, it is less clear what the drivers might be, but both phylogeny and environmental factors may play a role. We investigated host and environmental factors that underlie variation in gut microbiota composition in eight species of migratory shorebirds. We characterized bacterial communities from 375 fecal samples collected from adults of eight shorebird species captured at a network of nine breeding sites in the Arctic and sub-Arctic ecoregions of North America, by sequencing the V4 region of the bacterial 16S ribosomal RNA gene. Firmicutes (55.4%), Proteobacteria (13.8%), Fusobacteria (10.2%), and Bacteroidetes (8.1%) dominated the gut microbiota of adult shorebirds. Breeding location was the main driver of variation in gut microbiota of breeding shorebirds (R 2 = 11.6%), followed by shorebird host species (R 2 = 1.8%), and sampling year (R 2 = 0.9%), but most variation remained unexplained. Site variation resulted from differences in the core bacterial taxa, whereas rare, low-abundance bacteria drove host species variation. Our study is the first to highlight a greater importance of local environment than phylogeny as a driver of gut microbiota composition in wild, migratory birds under natural conditions.

Copyright © 2019 Grond, Santo Domingo, Lanctot, Jumpponen, Bentzen, Boldenow, Brown, Casler, Cunningham, Doll, Freeman, Hill, Kendall, Kwon, Liebezeit, Pirie-Dominix, Rausch and Sandercock.

KEYWORDS:
16S rRNA gene; breeding site; environment; gut microbiome; host health

PMID: 31649627 PMCID: PMC6795060 DOI: 10.3389/fmicb.2019.02258
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Select item 31649626
33.
Front Microbiol. 2019 Oct 9;10:2249. doi: 10.3389/fmicb.2019.02249. eCollection 2019.
Characterization of Aspergillus tamarii Strains From Human Keratomycoses: Molecular Identification, Antifungal Susceptibility Patterns and Cyclopiazonic Acid Producing Abilities.
Homa M1,2, Manikandan P3,4, Szekeres A2, Kiss N2, Kocsubé S2, Kredics L2, Alshehri B3, Dukhyil AAB3, Revathi R5, Narendran V5, Vágvölgyi C2, Shobana CS6, Papp T1,2.
Author information
1
MTA-SZTE "Lendület" Fungal Pathogenicity Mechanisms Research Group, Szeged, Hungary.
2
Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary.
3
Department of Medical Laboratory Sciences, College of Applied Medical Sciences, Majmaah University, Al Majma'ah, Saudi Arabia.
4
Greenlink Analytical and Research Laboratory (India) Private Limited, Coimbatore, India.
5
Aravind Eye Hospital and Postgraduate Institute of Ophthalmology, Coimbatore, India.
6
Department of Microbiology, PSG College of Arts & Science, Coimbatore, India.
Abstract
Aspergillus tamarii appears to be an emerging aetiological agent of human keratomycoses in South India. The investigated strains were isolated from six suspected fungal keratitis patients attending a tertiary care eye hospital in Coimbatore (Tamil Nadu, India), and were initially identified by the microscopic examinations of the scrapings and the cultures. Our data suggest that A. tamarii could be easily overlooked when identification is carried out based on morphological characteristics alone, while the sequence analysis of the calmodulin gene can be used successfully to recognize this species accurately. According to the collected clinical data, ocular trauma is a common risk factor for the infection that gradually developed from mild to severe ulcers and could be healed with an appropriate combined antifungal therapy. Antifungal susceptibility testing revealed that A. tamarii strains are susceptible to the most commonly used topical or systemic antifungal agents (i.e., econazole, itraconazole and ketoconazole) except for natamycin. Moreover, natamycin proved to be similarly less effective than the azoles against A. tamarii in our drug interaction tests, as the predominance of indifferent interactions was revealed between natamycin and econazole and between natamycin and itraconazole as well. Four and five isolates of A. tamarii were confirmed to produce cyclopiazonic acid (CPA) in RPMI-1640 - which is designed to mimic the composition of human extracellular fluids - and in yeast extract sucrose (YES) medium, respectively, which is a widely used culture medium for testing mycotoxin production. Although a ten times lower mycelial biomass was recorded in RPMI-1640 than in YES medium, the toxin contents of the samples were of the same order of magnitude in both types of media. There might be a relationship between the outcome of infections and the toxigenic properties of the infecting fungal strains. However, this remains to be investigated in the future.

Copyright © 2019 Homa, Manikandan, Szekeres, Kiss, Kocsubé, Kredics, Alshehri, Bin Dukhyil, Revathi, Narendran, Vágvölgyi, Shobana and Papp.

KEYWORDS:
Aspergillus tamarii; LC-MS/MS; antifungal drug susceptibilities; calmodulin; cyclopiazonic acid (CPA); drug interactions; keratitis; molecular identification

PMID: 31649626 PMCID: PMC6794953 DOI: 10.3389/fmicb.2019.02249
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Select item 31649625
34.
Front Microbiol. 2019 Oct 9;10:2233. doi: 10.3389/fmicb.2019.02233. eCollection 2019.
An iPSC-Derived Myeloid Lineage Model of Herpes Virus Latency and Reactivation.
Poole E1, Huang CJZ1, Forbester J2, Shnayder M3, Nachshon A3, Kweider B1, Basaj A1, Smith D1, Jackson SE1, Liu B1, Shih J1, Kiskin FN1, Roche K4, Murphy E4, Wills MR1, Morrell NW1, Dougan G1,5, Stern-Ginossar N3, Rana AA1, Sinclair J1.
Author information
1
Department of Medicine, University of Cambridge, Cambridge, United Kingdom.
2
Division of Infection and Immunity, School of Medicine, Cardiff University, Cardiff, United Kingdom.
3
Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel.
4
Cleveland Clinic, Lerner Research Institute, Cleveland, OH, United States.
5
Wellcome Trust Sanger Institute, Hinxton, United Kingdom.
Abstract
Herpesviruses undergo life-long latent infection which can be life-threatening in the immunocompromised. Models of latency and reactivation of human cytomegalovirus (HCMV) include primary myeloid cells, cells known to be important for HCMV latent carriage and reactivation in vivo. However, primary cells are limited in availability, and difficult to culture and to genetically modify; all of which have hampered our ability to fully understand virus/host interactions of this persistent human pathogen. We have now used iPSCs to develop a model cell system to study HCMV latency and reactivation in different cell types after their differentiation down the myeloid lineage. Our results show that iPSCs can effectively mimic HCMV latency/reactivation in primary myeloid cells, allowing molecular interrogations of the viral latent/lytic switch. This model may also be suitable for analysis of other viruses, such as HIV and Zika, which also infect cells of the myeloid lineage.

Copyright © 2019 Poole, Huang, Forbester, Shnayder, Nachshon, Kweider, Basaj, Smith, Jackson, Liu, Shih, Kiskin, Roche, Murphy, Wills, Morrell, Dougan, Stern-Ginossar, Rana and Sinclair.

KEYWORDS:
C2-iPSCs; dendritic cells; endothelial progenitor cells; human cytomegalovirus; induced pluripotent stem cells; latency; myeloid; viral carriage

PMID: 31649625 PMCID: PMC6795026 DOI: 10.3389/fmicb.2019.02233
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