Burden of serious fungal infections in Tanzania.

The incidence and prevalence of fungal infections in Tanzania remains unknown. We assessed the annual burden in the general population and among populations at risk. Data were extracted from 2012 reports of the Tanzanian AIDS program, WHO, reports, Tanzanian census, and from a comprehensive PubMed search. We used modelling and HIV data to estimate the burdens of Pneumocystis jirovecii pneumonia (PCP), cryptococcal meningitis (CM) and candidiasis. Asthma, chronic obstructive pulmonary disease and tuberculosis data were used to estimate the burden of allergic bronchopulmonary aspergillosis (ABPA) and chronic pulmonary aspergillosis (CPA). Burdens of candidaemia and Candida peritonitis were derived from critical care and/or cancer patients' data. In 2012, Tanzania's population was 43.6 million (mainland) with 1 500 000 people reported to be HIV-infected. Estimated burden of fungal infections was: 4412 CM, 9600 PCP, 81 051 and 88 509 oral and oesophageal candidiasis cases respectively. There were 10 437 estimated posttuberculosis CPA cases, whereas candidaemia and Candida peritonitis cases were 2181 and 327 respectively. No reliable data exist on blastomycosis, mucormycosis or fungal keratitis. Over 3% of Tanzanians suffer from serious fungal infections annually, mostly related to HIV. Cryptococcosis and PCP are major causes of mycoses-related deaths. National surveillance of fungal infections is urgently needed.

Association of lectin pathway proteins with intra-abdominal Candida infection in high-risk surgical intensive-care unit patients. A prospective cohort study within the fungal infection network of Switzerland

OBJECTIVES Human studies on the role of mannose-binding lectin (MBL) in patients with invasive candidiasis have yielded conflicting results. We investigated the influence of MBL and other lectin pathway proteins on Candida colonization and intra-abdominal candidiasis (IAC) in a cohort of high-risk patients. METHODS Prospective observational cohort study of 89 high-risk intensive-care unit (ICU) patients. Levels of lectin pathway proteins at study entry and six MBL2 single-nucleotide polymorphisms were analyzed by sandwich-type immunoassays and genotyping, respectively, and correlated with development of heavy Candida colonization (corrected colonization index (CCI) ≥0.4) and occurrence of IAC during a 4-week period. RESULTS Within 4 weeks after inclusion a CCI ≥0.4 and IAC was observed in 47% and 38% of patients respectively. Neither serum levels of MBL, ficolin-1, -2, -3, MASP-2 or collectin liver 1 nor MBL2 genotypes were associated with a CCI ≥0.4. Similarly, none of the analyzed proteins was found to be associated with IAC with the exception of lower MBL levels (HR 0.74, p = 0.02) at study entry. However, there was no association of MBL deficiency (<0.5 μg/ml), MBL2 haplo- or genotypes with IAC. CONCLUSION Lectin pathway protein levels and MBL2 genotype investigated in this study were not associated with heavy Candida colonization or IAC in a cohort of high-risk ICU patients.

Is fern endozoochory widespread among fern-eating herbivores?

Endozoochory is an important dispersal mechanism for seed plants and has recently been demonstrated to occur also in spore plants, such as ferns, which are commonly consumed by herbivores. However, it is not known whether fern species from particular habitats are differentially preferred by herbivores and whether their spores differ in their ability to survive the gut passage of herbivores. Such differences would suggest adaptation to endozoochorous dispersal, as it is known for seed plants. Moreover, it is unclear whether herbivore species differ in their efficiency to disperse fern spores. In a factorial experiment, we fed fertile leaflets of 13 fern species from different forest and open habitats to three polyphagous herbivore species and recorded the germination of spores from feces after 46 and 81 days. Fern spores germinated in 66 % of all samples after 46 days. At this stage, germination success differed among fern and herbivore species, but was independent of the ferns’ habitat. Interestingly, after 81 days fern spores germinated in 85 % of all samples and earlier significant differences in germination success among fern and herbivore species were not sustained. The overall high germination success and the absence of differences among fern species from different habitats together with the consistency across three tested herbivores strongly imply endozoochorous dispersal to be a taxonomically widespread phenomenon among fern-eating herbivores, which all might act as potential dispersal vectors. © 2015, Springer Science+Business Media Dordrecht.

Foliar fungal pathogens and grassland biodiversity

By attacking plants, herbivorous mammals, insects, and belowground pathogens are known to play an important role in maintaining biodiversity in grasslands. Foliar fungal pathogens are ubiquitous in grassland ecosystems, but little is known about their role as drivers of community composition and diversity. Here we excluded foliar fungal pathogens from perennial grassland by using fungicide to determine the effect of natural levels of disease on an otherwise undisturbed plant community. Importantly, we excluded foliar fungal pathogens along with rabbits, insects, and mollusks in a full factorial design, which allowed a comparison of pathogen effects along with those of better studied plant enemies. This revealed that fungal pathogens substantially reduced aboveground plant biomass and promoted plant diversity and that this especially benefited legumes. The scale of pathogen effects on productivity and biodiversity was similar to that of rabbits and insects, but different plant species responded to the exclusion of the three plant enemies. These results suggest that theories of plant coexistence and management of biodiversity in grasslands should consider foliar fungal pathogens as potentially important drivers of community composition.

A fungal endophyte helps plants to tolerate root herbivory through changes in gibberellin and jasmonate signaling

Plant–microbe mutualisms can improve plant defense, but the impact of root endophytes on below-ground herbivore interactions remains unknown. We investigated the effects of the root endophyte Piriformospora indica on interactions between rice (Oryza sativa) plants and its root herbivore rice water weevil (RWW; Lissorhoptrus oryzophilus), and how plant jasmonic acid (JA) and GA regulate this tripartite interaction. Glasshouse experiments with wild-type rice and coi1-18 and Eui1-OX mutants combined with nutrient, jasmonate and gene expression analyses were used to test: whether RWW adult herbivory above ground influences subsequent damage caused by larval herbivory below ground; whether P. indica protects plants against RWW; and whether GA and JA signaling mediate these interactions. The endophyte induced plant tolerance to root herbivory. RWW adults and larvae acted synergistically via JA signaling to reduce root growth, while endophyte-elicited GA biosynthesis suppressed the herbivore-induced JA in roots and recovered plant growth. Our study shows for the first time the impact of a root endophyte on plant defense against below-ground herbivores, adds to growing evidence that induced tolerance may be an important root defense, and implicates GA as a signal component of inducible plant tolerance against biotic stress.

Effects of Nosema apis, N. ceranae, and coinfections on honey bee (Apis mellifera) learning and memory

Western honey bees (Apis mellifera) face an increasing number of challenges that in recent years have led to significant economic effects on apiculture, with attendant consequences for agriculture. Nosemosis is a fungal infection of honey bees caused by either Nosema apis or N. ceranae. The putative greater virulence of N. ceranae has spurred interest in understanding how it differs from N. apis. Little is known of effects of N. apis or N. ceranae on honey bee learning and memory. Following a Pavlovian model that relies on the proboscis extension reflex, we compared acquisition learning and long-term memory recall of uninfected (control) honey bees versus those inoculated with N. apis, N. ceranae, or both. We also tested whether spore intensity was associated with variation in learning and memory. Neither learning nor memory differed among treatments. There was no evidence of a relationship between spore intensity and learning, and only limited evidence of a negative effect on memory; this occurred only in the co-inoculation treatment. Our results suggest that if Nosema spp. are contributing to unusually high colony losses in recent years, the mechanism by which they may affect honey bees is probably not related to effects on learning or memory, at least as assessed by the proboscis extension reflex.

Investigating the Role of Small, Acid-Soluble Spore Proteins (SASPs) in the Resistance of Clostridium Perfringens Spores to Heat.

BACKGROUND: Clostridium perfringens type A food poisoning is caused by enterotoxigenic C. perfringens type A isolates that typically possess high spore heat-resistance. The molecular basis for C. perfringens spore heat-resistance remains unknown. In the current study, we investigated the role of small, acid-soluble spore proteins (SASPs) in heat-resistance of spores produced by C. perfringens food poisoning isolates. RESULTS: Our current study demonstrated the presence of all three SASP-encoding genes (ssp1, 2 and 3) in five surveyed C. perfringens clinical food poisoning isolates. beta-Glucuronidase assay showed that these ssp genes are expressed specifically during sporulation. Consistent with these expression results, our study also demonstrated the production of SASPs by C. perfringens food poisoning isolates. When the heat sensitivities of spores produced by a ssp3 knock-out mutant of a C. perfringens food poisoning isolate was compared with that of spores of the wild-type strain, spores of the ssp3 mutant were found to exhibit a lower decimal reduction value (D value) at 100 degrees C than exhibited by the spores of wild-type strain. This effect was restored by complementing the ssp3 mutant with a recombinant plasmid carrying wild-type ssp3, suggesting that the observed differences in D values between spores of wild-type versus ssp3 mutant was due to the specific inactivation of ssp3. Furthermore, our DNA protection assay demonstrated that C. perfringens SASPs can protect DNA from DNase I digestion. CONCLUSION: The results from our current study provide evidences that SASPs produced by C. perfringens food poisoning isolates play a role in protecting their spores from heat-damage, which is highly significant and relevant from a food safety perspective. Further detailed studies on mechanism of action of SASPs from C. perfringens should help in understanding the mechanism of protection of C. perfringens spores from heat-damage.

INTERACTION OF BACILLUS ANTHRACIS EXOSPORIUM PROTEIN BCLA WITH COMPLEMENT FACTOR H AND SPORE PERSISTENCE IN THE LUNG

Anthrax outbreaks in the United States and Europe and its potential use as a bioweapon have made Bacillus anthracis an interest of study. Anthrax infections are caused by the entry of B. anthracis spores into the host via the respiratory system, the gastrointestinal tract, cuts or wounds in the skin, and injection. Among these four forms, inhalational anthrax has the highest lethality rate and persistence of spores in the lungs of animals following pulmonary exposure has been noted for decades. However, details or mechanisms of spore persistence were not known. In this study, we investigated spore persistence in a mouse model. The results suggest that B. anthracis spores have special properties that promote persistence in the lung, and that there may be multiple mechanisms contributing to spore persistence. Moreover, recent discoveries from our laboratory suggest that spores evolved a sophisticated mechanism to interact with the host complement system. The complement system is a crucial part of the host defense mechanism against foreign microorganisms. Knowledge of the specific interactions that occur between the complement system and B. anthracis was limited. Studies performed in our laboratory have suggested that spores of B. anthracis can target specific proteins, such as Factor H (fH) of the complement system. Spores of B. anthracis are enclosed by an exosporium, which consists of a basal layer surrounded by a nap of hair-like filaments. The major structural component of the filaments is called Bacillus collagen-like protein of anthracis (BclA), which comprises a central collagen-like region and a globular C-terminal domain. BclA is the first point of contact with the innate system of an infected host. In this study, we investigated the molecular details of BclA-fH interaction with respect to the specific binding mechanism and the functional significance of this interaction in a murine model of anthrax infection. We hypothesized that the recruitment of fH to the spore surface by BclA limits the extent of complement activation and promotes pathogen survival and persistence in the infected host. Findings from this study are significant to understanding how to treat post-exposure prophylaxis and improve our knowledge of spores with the host immune system.

Numer and type of seeds introduced by footwear of travelers to Svalbard and germination success in 2008

Expanding visitation to Polar regions combined with climate warming increases the potential for alien species introduction and establishment. We quantified vascular plant propagule pressure associated with different groups of travelers to the high-Arctic archipelago of Svalbard, and evaluated the potential of introduced seeds to germinate under the most favorable average Svalbard soil temperature (10°C). We sampled the footwear of 259 travelers arriving by air to Svalbard during the summer of 2008, recording 1,019 seeds: a mean of 3.9 (±0.8) seeds per traveler. Assuming the seed influx is representative for the whole year, we estimate a yearly seed load of around 270,000 by this vector alone. Seeds of 53 species were identified from 17 families, with Poaceae having both highest diversity and number of seeds. Eight of the families identified are among those most invasive worldwide, while the majority of the species identified were non-native to Svalbard. The number of seeds was highest on footwear that had been used in forested and alpine areas in the 3 months prior to traveling to Svalbard, and increased with the amount of soil affixed to footwear. In total, 26% of the collected seeds germinated under simulated Svalbard conditions. Our results demonstrate high propagule transport through aviation to highly visited cold-climate regions and isolated islands is occurring. Alien species establishment is expected to increase with climate change, particularly in high latitude regions, making the need for regional management considerations a priority.