Total Spore Research Articles

Selecting alternative sterile and non-sterile substrates for mycorrhizal inoculant production

Alternative substrates were evaluated for mycorrhizal inoculants production considering the beneficial effects of arbuscular mycorrhizal fungi (AMF) for plants and environment. The first step of the experiment aimed at evaluating the potential of substrates produced from sugarcane bagasse (SB), coconut fibre (CF) and urban waste compost (UWC) to produce AMF inoculants, by using Brachiaria decumbens as multiplier plant. The experiment has followed a randomized block design, at 7x3 factorial arrangement (seven substrates: SB, CF, SB+CF 1:1, SB+UWC 3:1, CF+UWC 3:1, SB+CF+UWC 3:3:2, Soil+Sand 3:1, vs. three substrate preparations: inoculated/sterilized, inoculated/non-sterilized, non-inoculated/sterilized). Inoculums produced in the first experimental stage were tested at the second stage, based on the inoculated/sterilized preparation. Seed germination, dry shoot biomass, mycorrhizal root rate and total spore production were assessed in both tests. There was significant decrease in seed emergence in organic substrates in relation to Soil+Sand, although the plants growth in organic substrates was greater. Artificial inoculation was not superior to spontaneous substrate mycorrhization or affected inoculum production. Mycorrhizal colonization of roots was equivalent in most organic substrates and in Soil+Sand. However, spore production stood out in organic substrate mixes, mainly when CF and UWC were used. This finding was confirmed at the second experimental stage.

Composition and seasonal variation of the arbuscular mycorrhizal fungi spore community in litter, root mat, and soil from a subtropical rain forest

Community composition and seasonal variation of sporulation of arbuscular mycorrhizal fungi (AMF) have been studied in soils from many ecosystems including subtropical forest. Yet, AMF community composition has been surveyed only from the mineral soil but not from the litter layer and the root mat, and long-term variation in sporulation is not fully understood. We sampled a 75-m2 plot from a subtropical forest to determine AMF community composition in the following habitats: the litter layer, the root mat, and the mineral soil. Moreover, samples were taken in fall, winter, spring, and summer over a 2-year period to follow the seasonal variation of AMF sporulation. We detected 47 AMF species belonging to six families and 14 genera, Glomeraceae and Acaulosporaceae being the most represented families. Sixteen species were common to all three habitats, five species were shared between two habitats, and 26 species were recovered exclusively from single habitats. While species richness was not significantly different among habitats, AMF total spore numbers were significantly higher in the litter and root mat compared to the soil. PERMANOVA did not detect a significant effect of habitats on community composition when species presence/absence was considered, but significant differences between litter versus soil and root mat versus soil were detected when spore abundance was considered. A seasonal pattern of spore abundance for species was not observed over the 2-year sampling period regardless of habitat. This study revealed that (i) different AMF species sporulate in the different habitats; thus, field surveys considering only the mineral soil might underestimate species richness and (ii) AMF species sporulate asynchronously in subtropical forest.

First volumetric records of airborne Cladosporium and Alternaria spores in the atmosphere of Al Khor (northern Qatar): a preliminary survey

Daily monitoring of airborne fungal spores was carried out for the first time in Al Khor city, Qatar, using a Hirst type 7-day recording volumetric spore trap, from May 2017 to May 2019. During the sampling period, the annual and monthly fluctuations, as well as intradiurnal variations of airborne fungal spore concentrations, were evaluated. Cladosporium, followed by Alternaria, were the spore types most abundant in the atmosphere of the city, with a strong interannual variability in the atmospheric concentrations being observed. The Annual Spore Integrals (ASIns) were 3334 and 1172 spore * day/m3 (2017–2018), and 6796 and 1538 spore * day/m3 (2018–2019) for Cladosporium and Alternaria, respectively. Total daily spore concentrations showed significantly positive correlations with mean, minimum, and maximum temperatures but significantly negative correlations with relative humidity. However, due to the scarce rainfalls’ days, we did not find a statistically significant correlations between Cladosporium and Alternaria spore concentrations and this parameter. Despite this, the spore peaks were strongly related to precipitations that occurred during the previous month. In general, no significant correlations were found with wind speed but, regarding wind direction, the higher percentage of spores were collected when wind blows from the 4th quadrant (NW). According to the intradiurnal pattern, Cladosporium fungal spores displayed their maximum daily concentration during 8:00–10:00 h in the morning, with a second peak in the afternoon, while for Alternaria, the maximum peaks were observed between 08:00 and 14:00 h. Because no consistent previous aerobiological studies exist from Qatar, the aim of this study is to define the seasonality and intradiurnal behaviour of these two airborne fungal spore and the role that, in such arid scene, the meteorological parameters play on the spore concentrations.

Impact of High-Pressure Processing (HPP) on Selected Quality and Nutritional Parameters of Cauliflower (Brassica oleracea var. Botrytis)

In recent years, innovative food processing methods, such as high-pressure processing (HPP) treatment, have been shown to improve food quality. The purpose of this work was to determine the effects of high-pressure processing (HPP; 400 and 600 MPa for 2 or 5 min, 20 °C) of cauliflower. Microbial shelf-life (total aerobic count and spores), texture, color, drip loss, dry matter, antioxidative capacity, total phenolic content, and ascorbic acid were analyzed before and after processing, as well as during storage (4 °C) for up to 42 days. Among the different treatments, HPP at 600 MPa exhibited low microbial counts between days 14 and 28 of storage, while at 400 MPa already had high bacterial counts between days 7 and 14. HPP at both 400 and 600 MPa was the best method to maintain the color during storage. The texture of the cauliflower did not differ from the control during storage for HPP. For all samples, the dry matter content remained stable during storage, with few differences between treatments. The nutritional quality of high-pressure-processed cauliflower at 600 MPa for 2 min remained high until day 28. The overall results of this study demonstrate that HPP has the potential to preserve the quality of cauliflower.

Effect of bactofugation of raw milk on total bacterial and aerobic spore counts and on microbial diversity of sporeformers

This study describes the effect of bactofugation (10,000 × g in a continuous flow of 10,000 L/h) of three batches of raw milk on total bacterial count (TBC) and aerobic spore count, and it also shows the effect on the microbial diversity of spore-forming bacteria by analysing their genetic variability through molecular approaches. Given that milk must be preheated to approximately 55 °C before being bactofuged, for comparison, the three batches were evaluated at different stages as refrigerated raw, preheated, and bactofuged milk. For preheated milk, it was found that bactofugation caused a significant reduction (p < 0.05) of 99.52% (from 4.5 × 106 to 2.1 × 104 CFU/mL) in the mean TBC and of 95% (from 333 to 17 CFU/mL) in the aerobic mesophilic spore count. Due to the effect of bactofugation on preheated milk, a reduction of 82% was observed in both TBC and aerobic spore count. With respect to diversity, 107 isolates from raw milk, prior to bactofugation, and 16 isolates from bactofuged milk were recovered and grouped into 40 and 8 clusters, respectively. The predominant species detected in raw and preheated milk were Bacillus toyonensis (63% - 20 clusters) and Lysinibacillus fusiformis (15% - 8 clusters). Proportionally, B. toyonensis (69% - 6 clusters) and L. fusiformis (25% - 1 cluster) were predominant in bactofuged milk. B. pumilus, L. varians, B. flexus, B. invictae, and B. megaterium, bacteria with a known milk spoilage potential, were isolated from milk prior to bactofugation, and they reduced to undetectable levels in bactofuged milk. Bactofugation of milk, therefore, reduces the TBC and aerobic spore count, with a significant effect in reducing the microbial diversity of spore-forming bacteria, proportional to their incidence in raw milk. Therefore, bactofugation can be an alternative to increase the shelf life and technological potential of milk.

Three-year pollen and fungi calendar in a Mediterranean region of the Northeast Greece.

Pollen calendars have been proved clinically important in allergic disease management, as differences in airborne allergens exist not only between different countries but also between regions of the same country as well. This study aims to provide new data regarding the atmospheric pollen and fungi content of a Mediterranean region (Western Thrace/North-East Greece) and discuss seasonal trends, differences in pollen grains and fungi spores' circulation over the years, and correlations with climate parameters. A 7-day continuously running volumetric trap was used to collect circulating pollen grains and fungi spores. Pollen taxa and fungi were characterized by standard protocols and counted as grains /m3 and average total grains and spores. The primary allergenic pollen season was discovered, and their 10-day averages were measured over time. Correlations with temperature, rain, and humidity were assessed by single linear regression analysis. Pollen grains from nine pollen families were identified, including five arboreal, two nonarboreal taxa, and spores from two fungi species. The three most prevalent taxa were Oleaceae, Poaceae, Pinaceae, and Cladosporium in the fungi. Peak pollen concentrations were detected during April and May, with daily averages exceeding 170 grains/m3. Poaceae presented the longest pollen season of 342 days and Oleaceae the shortest, extending to only 110 days, during the 3years. Cladosporium was the fungus with the highest spore concentration (180,129.9 spores) compared with Alternaria (28,026.1 spores). Correlations with meteorological parameters showed variable associations among different taxa, with rainfall and relative humidity being the most significant determinants. In this study, the pollenic and fungal spectrum of a Mediterranean region and information that can be proved clinically significant for the appropriate diagnostic and therapeutic approach of allergic patients was presented.

Rapid detection of Geobacillus and Anoxybacillus species by quantitative qPCR (qPCR) in commercial dairy products

AbstractThermophilic spore‐forming bacteria, especially Anoxybacillus and Geobacillus species, are a major problem for dairy industry. The presence of these thermophilic bacilli in the dairy products is considered a poor hygiene indicator during product processing. The commonly preferred culture‐dependent detection methods are time consuming. Therefore, the development of rapid and reliable molecular approaches for the detection of these problematic microorganisms in food processing is essential. In this context, specific primers for the gene (spo0A) that initiates sporulation were designed for Anoxybacillus kamchatkensis subsp. asaccharedens (F81) and Geobacillus thermodenitrificans (DSM 465T), which have been shown to be strong biofilm producers in dairy products. For this purpose, a quantitative polymerase chain reaction (qPCR) assay was developed. The qPCR standard curves obtained with these primers allowed a total viable cell count in the range of 101–108 CFU/ml for G. thermodenitrificans, while the spore count was in the range of 103–108 CFU/ml. The primer developed for A. kamchatkensis subsp. asaccharedens was able to detect viable total cells and spores with much higher sensitivity (101–108 CFU/ml viable total cells, 102–108 CFU/ml spores). The primers developed in this study allowed separate detection of Anoxybacillus and Geobacillus in dual culture experiments. The primers and method developed in this study can also be used for rapid detection of Anoxybacillus and Geobacillus contamination in mixed cultures.

The Effect of The Application of Soil Biostructures Created Using Biochar and Seaweed Extract on Upland Rice Growth

Earthworms play an important role in mixing soil particles with biochar grains, as well as creating biostructures, and the application of seaweed extract to soil affects the microbes within, as well as plant growth. This study, therefore, aims to investigate the effect of mixing soil, teak leaf biochar, as well as seaweed extract on the arbuscularmycorrhizal fungal (AMF) spores within the biostructures formed, and analyze the effect of applying these biostructures to planting media soil on the growth and yield of local upland rice. Before the experiment, extract stock from Sargassum sp. was diluted with water into five separate concentration levels, 0%, 20%, 40%, 60%, and 80%. Subsequently, 20 individual earthworms were released on the soil surface previously mixed with biochar and seaweed extract in a reactor. The planting media used in this study was soil from the cogongrass area with grain sizes below 4 mm, and about 10% (w/w) of the biostructures formed were added to the media in a polybag, then the mixture was transplanted with upland rice seedlings of local variety Sorawolia.According to the results, the treatment containing had the highest total AMF spores. Furthermore, the addition of biostructures significantly affected plant height, leaf number as well as area, and the number of tillers at 42, 42 to 70, and 70 days after application, respectively. Meanwhile, the highest plant dry weight and panicle length were obtained from the treatments containing 80% and 60% extract stock, respectively. However, there was no significant difference in the spikelet number and percentage of filled spikelets between the biostructures. Therefore, the application of both teak leaf biochar and extract of Sargassum sp. was concluded to be able to improve the performance of earthworms (Pheretima sp.) in creating soil biostructures containing AMF spores, for local upland rice development in conditions of poor soil fertility. However, future studies are required to investigate this application’s potential as a source of inoculum for AMF spores or other beneficial microbes, for application at the smallholder farm level.

Bioaerosol vertical fungal spores profile in Minas Gerais State, Brazil

Primary biological aerosol particles (PBAPs) are involved in multiple phenomena ranging from seasonal allergies to pandemic diseases. Furthermore, PBAPs that act as ice nuclei, might interact with cloud physics affecting the formation of hail and, potentially, causing damage to agriculture. These latter dynamics are still unclear, especially due to the lack of knowledge about PBAPs concentration and emission rates. Here we characterized the fungal aerobiology of Arceburgo, Minas Gerais State, Brazil, through ground level and airborne sampling of PBAPs via a hot-air balloon. Total and cultivable fungal spores were collected using personal portable Burkard and a MAS100 sampler respectively during the summer and winter of 2019. In the latter season, daily dynamics were resolved by repeating flights and sampling in the morning and in the afternoon. Both samplers identified a core fungal community (Penicillum/Aspergillus and Cladosporium spp.) that are coupled with local meteorological dynamics and are able to undergo atmospheric transport as indicated by their survival in the night-time residual boundary layer. These results are invaluable in identifying a core set of aerobiological indicators that can be used in future works to unravel PBAPs emission rates on the area of Arceburgo and form a basis to close the gap in knowledge in the interplay between PBAPs and hail formation.

Seaweed extract effect on arbuscular mycorrhizae spore in soil engineered by earthworm, and the soil effect on upland rice growth

Seaweed extract is known to contain nutrients and growth-regulating substances that affect soil biota, and a source of protection against pests and diseases. Earthworm, which is an example of a soil biota and playing the role of ecosystem engineer, has the ability to produce suitable land biostructures, for the inhabitation of arbuscular mycorrhizal fungi (AMF), which has an impact on upland rice growth. Therefore, this study aims to determine, (i) the effect of seaweed extract on the population of earthworms and spores of arbuscular mycorrhizal fungi, and (ii) the impact of the engineered soil on the growth of local upland rice varieties. Furthermore, the extract of seaweed, such as Kappapychus alvarezii, was divided into five concentration levels, namely 0%, 20%, 40%, 60%, and 80%. Each treatment was drenched into the soil from the cogongrass vegetated area, mixed with 20 Pheretima sp., and maintained for 49 days in the greenhouse. The result showed that the total difference in the earthworms’ concentration treatments was not significant. It also showed that the total AMF spores in the engineered soil products of 20% concentration was the highest. Based on treatment with the earthworm engineered soil products, the highest and lowest vegetative growth and yield components of upland rice were observed at the concentrations of 80% and 0%, respectively. In conclusion, the application of seaweed extract to the soil did not significantly reduce the earthworm population. The extract concentration of 20% also increased the total AMF spore in the engineered soil. Moreover, highly treated engineered soil products increased the growth and yield components of upland Kambowa rice on cogongrass soils.

Characterization of arbuscular mycorrhizal fungal communities associated withvineyards in northwestern Iran

Arbuscular mycorrhizal fungi (AMF) establish beneficial symbiotic associations with plants, enhancing their nutrient uptake, growth, and stress tolerance. The present study was aimed to investigate AMF spore density, species composition, mycorrhizal colonization patterns, and correlation of these indices with soil physicochemical parameters at four vineyards located in one of the most important grape-producing regions of Iran (West Azerbaijan province). Forty-three soil samples were collected from four grapeproducing regions during July-August 2019. The total spore abundance ranged from 39-647 spores per 100 g dry soil. Twelve AMF species, representing six genera (Rhizophagus, Funneliformis, Glomus, Septoglomus, Claroideoglomus, and Scutellospora) were identified. Rhizophagus fasciculatus was the most frequently found species, with a frequency of 75%. Two of the identified species, G. glomerulatum and Scutellospora calospora are new for the mycoflora of Iran. Significant negative correlations were detected between AMF attributes [spore density, AMF colonization frequency (F%) as well as AMF colonization intensity (M%)] and soil phosphorus content. The results provide insights into the AMF communities and dynamics in vineyards as influenced by soil parameters, improving our understanding of soil biological fertility in grape production systems.

Validation of a real-time PCR method on pta gene for Clostridium tyrobutyricum quantification in milk

In the dairy industry, the late blowing defect in medium and long ripened cheeses causes important economic losses. This cheese defect, caused mainly by the anaerobic spore former Clostridium tyrobutyricum , is characterized by gas production resulting in holes formation in the paste, and in unpleasant aromas related to the butyrate production. Since longtime, the reference method used to detect the presence of total spore number in milk is the Most Probable Number (MPN), a semi-quantitative method which measures the bacterial growth and the gas production after heat treatment of the samples. This method often gives uncertain results, it requires long incubation periods and fails to differentiate between different species of spore-forming bacteria. A TaqMan real-time quantitative PCR targeting the phosphotransacetylase gene ( pta ) for C. tyrobutyricum was previously developed as an alternative technique to the traditional method, faster and more specific, and therefore of great interest to preventively determine the contamination of milk by C. tyrobutyricum . The aim of this work was the validation of this quantitative real-time PCR protocol for the C. tyrobutyricum detection in milk. Following the method validation, 120 samples of UHT and raw milk artificially contaminated with C. tyrobutyricum spores were analyzed in increasing concentrations, relating the results of the molecular method with those obtained by the MPN. Finally, 144 raw milk samples with a possible natural contamination were analyzed and demonstrated a positivity rate of 15.28% (CI95% 10.31–22.05%). • Validation of a real-time PCR for the C. tyrobutyricum detection in milk. • Method application on both spiked and naturally contaminated samples. • Rapid method to monitor the milk quality to avoid the late blowing defect.

Outdoor Mold and Respiratory Health: State of Science of Epidemiological Studies

Fungal spores are the predominant biological particulates in outdoor air. However, in contrast to pollens or outdoor air pollution, little is known about their respiratory health risks. The objectives were to conduct the first review of epidemiological studies on the short- and long-term effects of outdoor mold exposure on respiratory health in children and adults. Health outcomes included asthma, lung function, and rhinitis. Cross-sectional and longitudinal epidemiological studies using quantitative measures of outdoor mold exposure (optical microscopy, culture-based methods) were selected, providing that important confounding factors including temporal trends or meteorological factors were accounted for. A systematic literature search was performed up to June 2020, leading to the selection of 37 publications. Most studies were longitudinal and investigated short-term effects. There is evidence of an association between outdoor fungal exposure and an increase in asthma exacerbation among children for total spores, 2 phyla (ascomycetes, basidiomycetes), and 2 taxa (Cladosporium, Alternaria). A few studies also suggested an association for Coprinus, Ganoderma, Aspergillus-Penicillium, Botrytis, and Epicoccum in children, but this needs to be confirmed. Some studies reported mold associations with rhinitis, lung function, and among adults, but these were few in number or inconsistent. Further ecological studies in different regions that measure exposure to all taxa over several years are required to better understand their impact on rhinitis, asthma exacerbations and lung function. Larger panel studies are necessary to identify threshold effects in susceptible individuals. Finally, further research should assess the long-term effects of outdoor mold.

Occurrence of Clostridium perfringens vegetative cells and spores throughout an industrial production process of black soldier fly larvae (Hermetia illucens)

The main use of black soldier fly larvae (Hermetia illucens) is currently as an animal feed ingredient. While the bacterial community of the larvae has been characterised repeatedly via sequencing, microbiological safety assessment based on culture-dependent techniques is still scarce. This study focused on the occurrence of the spore-forming foodborne pathogen Clostridium perfringens during rearing and consecutive processing of the larvae, based on observations in a single rearing facility. C. perfringens vegetative cells and spores were determined, in addition to total viable counts, total aerobic spore counts and intrinsic parameters including pH, water activity and moisture content. All samples were obtained from an industrial production plant. In a preliminary experiment, substrate ingredients and dried larvae were analysed, but the larvae were produced with a previous batch of the substrate mixture. A second, more detailed, experiment was performed where all samples were collected sequentially from the same production run (substrate ingredients, substrate mixture, starting larvae, harvested larvae, residue, dried larvae and stored dried larvae). In the two experiments, (presumptive) C. perfringens, as determined on tryptose sulphite cycloserine agar, was found at low numbers in the ingredients and in the second experiment it was also found in the substrate mixture. Over the two experiments, total C. perfringens counts (i.e. vegetative cells plus spores) ranged between 3.0±0.1 and <1.2±0.5 log cfu/g and C. perfringens spores ranged between 2.5±0.1 and <1.0±0.0 log cfu/g. Interestingly, vegetative cells and spores of C. perfringens were below the detection limit in all larvae samples. Therefore, it appears that at this production site and based on the samples investigated, the pathogen did not colonise the larvae. However, these results indicate that insect producers should monitor this pathogen among others, and install good hygiene practices to avoid contamination.

Does evidence support measuring spore counts to identify dampness or mold in buildings? A literature review.

To identify dampness or mold (D/M) in buildings, investigators generally inspect for observable D/M indicators, the presence of which justifies remediation. Investigators may also use microbiological measurement and interpretation strategies with uncertain scientific support. We assessed available evidence supporting uses of spore counts, the microbiological measurement most commonly used to assess D/M. We reviewed published studies assessing relationships between spore counts and observable D/M, across buildings with different observable D/M levels. Penicillium/Aspergillus counts were consistently elevated in damp vs. reference (dry or outdoor) locations. Total spore counts provided a weaker, less consistent signal. The most detailed published analysis could distinguish groups of damp homes but not individual damp homes. Evidence did not validate current interpretations of spore count data for identifying single damp homes. Thus, such interpretations rest primarily on professional judgment. An additional series of informative but ineligible articles demonstrated an unconventional, more powerful "statistically based" comparison of multiple indoor vs. outdoor spore counts for identifying elevated indoor spores (and assumed D/M). Findings suggest that validation of enhanced spore trap approaches, including more samples indoors and outdoors plus statistically based comparisons of specific fungal groups, may allow evidence-based microbial identification of probable dampness in individual buildings.

Arbuscular Mycorrhizal Fungi Association with Some Selected Medicinal Plants

Arbuscular mycorrhizal fungi (AMF) are group of fungi of the order Glomales that form symbiotic association with plant roots and enhance the uptake of nutrients, and improve plant growth and yield. This study was conducted to investigate the occurrence of arbuscular mycorrhizal fungi in the rhizospheres of some commonly grown medicinal plants in Maiduguri viz; Aloe vera, Mentha, Cymbopogon citrates and Ocimum gratissimum. The results revealed all the plants have formed mycorrhiza symbiosis. Arbuscular mycorrhizal fungi spores from five genera (Glomus, Acaulospora, Dentiscutata, Scutellispora and Gigaspora were isolated and identified. Cymbopogon citrates significantly recorded the highest total AMF spore counts (90±4.17) while Aloe vera recorded the least (54±2.28). Amongst the five mycorrhiza genus Glomus species were comparatively higher under all plant species, while, Dentiscutata and Gigaspora had the lowest spore counts. Highest percent root colonization (72±4.23%) was recorded under Cymbopogon citrates and Aloe vera recorded the least (55.5 ±2.41%). The study confirmed mycorrhiza association with all the plants, however, AMF spore counts diversity varies with plant species. Arbuscular mycorrhizal fungi could be inoculated to soils with scanty or ineffective spores for enhanced plant nutrition and growth of medicinal plants.

Inactivation of fungal spores from clinical environment by silver bio-nanoparticles; optimization, artificial neural network model and mechanism

The present study aimed to assess the efficiency of silver bio-nanoparticles (Ag-NPs) in inactivating of the Aspergillus fumigatus, A. parasiticus and A. flavus var. columnaris and A. aculeatus spores. The AgNPs were synthesized in secondary metabolic products of Penicillium pedernalens 604 EAN. The inactivation process was optimized by response surface methodology (RSM) as a function of Ag NPs volume (1–10 μL/mL); time (10–120 min); pH (5–8); initial fungal concentrations (log10) (3–6). The artificial neural network (ANN) model was used to understand the behavior of spores for the factors affecting inactivation process. The best conditions to achieved SAL 10−6 of the fungal spores were recorded with 3.46 μl/mL of AgNPs, after 120 min at pH 5 and with 6 log of initial fungal spore concentrations, at which 5.99 vs. 6.09 (SAL 10−6) log reduction was recorded in actual and predicted results respectively with coefficient of 87.00%. The ANN revealed that the timehas major contribution in the inactivation process compare to Ag NPs volume. The fungal spores were totally inactivated (SAL 10−6, 6 log reduction with 99.9999%) after 110 min of the inactivation process, 10 min more was required to insure the irreversible inactivation of the fungal spores. The absence of protease and cellulase enzymes production confirm the total inactivation of the fungal spores. FESEM analysis revealed that the AgNPs which penetrated the fungal spores leading to damage and deform the fungal spore morphology. The AFM analysis confirmed the total spore surface damage. The bands in the range of the Raman spectroscopy from 1300 to 1600 cm−1 in the inactivated spores indicate the presence of CH3, CH2 and the deformation of lipids released outside the spore cytoplasm. These finding indicate that the AgNPs has high potential as a green alternative inactivation process for the airborne fungal spores.

Isolation and identification of indigenous Arbuscular Mycorrhizal Fungi (AMF) of forest clove rhizosphere from Maluku, Indonesia

Abstract. Mahulette AS, Alfian A, Kilkoda KA, Lawalata IJ, Marasabessy DA, Tanasale VL, Makaruku MH. 2021. Isolation and identification of indigenous Arbuscular Mycorrhizal Fungi (AMF) of forest clove rhizosphere from Maluku, Indonesia. Biodiversitas 22: 3613-3619. Forest clove is classified as wild-type and endemic to the Maluku (Moluccas) Islands, Indonesia. The different condition of growing areas causes various types of Arbuscular Mycorrhizal Fungi (AMF) associated with forest clove. The study aimed to identify and obtain indigenous AMF inoculums from the forest clove rhizosphere from two distribution areas in Maluku. The results of AMF identification found two types of spores from the genus Glomus in the rhizosphere of forest cloves from Ambon Island with a spore density of 35/50 g of soil. In comparison, three spores were found in Seram Island, two from the genus Scutellospora and one from the Acaulospora. With an overall spore density of 5/50 g of soil. After culture trapping, there was a change in type and an increase in spore density in soil samples from the rhizosphere of the two forest clove distribution areas. Soil samples from Ambon after trapping culture obtained two new types of spores from the genus Acaulospora with a total spore number of 57/50 g soil while in soil samples from Seram found three new types of spores from the genus Glomus with a total spore count of 104/50 g of soil.

Analyzing the impact of different dryland cropping histories in Southern NSW Australia on mycorrhizal colonization and biomass of upland cereal and legume crops in glasshouse

This study aimed to examine the impacts of different cropping sequences of dryland crops in southern NSW Australia on root colonization levels by the native arbuscular mycorrhizal fungi (AMF) of the soil and biomass weight of some upland cereal and legume crops (sorghum, oats, soybean, and sub-clover) grown on the soil samples in the glasshouse of the University of Western Sydney. The field soil samples were taken from southern NSW areas having different histories of dryland cropping, namely pasture only (PO), pasture-canola-wheat (PCW), and pasture-wheat (PW). For each category of cropping history, there were two sites sampled, each with two bulk field replicates. Each replicate of field soil sample was also analyzed for its content of nutrients and AMF spores and colonization levels of the field crop roots. The results indicated that there were no significant different in soil properties between categories of cropping history, except for Mg and Na contents, which were highest in PO than in PCW and PW soil. There were positive significant correlation between field root colonization and sub-clover colonization and soybean biomass, between total spores and colonization of sorghum and sub-clover, between available P and biomass of sorghum, sub-clover and oats, between Mg or Na and sorghum colonization, between Ca and oats biomass, and negative correlation between Mg and sorghum biomass. However, there were significant interaction between cropping history and several soil properties, indicating significant impacts of cropping history on the relationship between soil properties or AMF colonization and biomass of the glasshouse crops

Biopesticide production using Bacillus thuringiensis kurstaki by valorization of starch industry wastewater and effluent from aerobic, anaerobic digestion

Unconventional alternatives such as aerobic and anaerobic effluent from starch industry contain essential nutrients for Btk active ingredient synthesis. Effluent from starch industry is rich in carbon and nitrogen and can replace expensive feedstock used during the fermentation process. The main objective of this study was to achieve a biopesticide formulation from starch industry wastewater (SIW) with high entomotoxicity (UI/ml) of larvae comparable to Foray 76B, which is a commercial biopesticide. Bacillus thuringiensis var kurstaki HD1 (Btk) strain was cultivated and sub-cultured to aerobic, anaerobic digested effluent and SIW. Pre-treatment was carried on these different substrates to enhance the residual carbon required for Btk growth and delta endotoxin synthesis. After 48 hours of fermentation, cells count and delta-endotoxin were determined. A biopesticide formulation containing fermented broth and adjuvants was fed to larvae to determine larvae mortality. Btk cell growth and sporulation profile in SIW media displayed a high total cell count and viable spores compared to btk growth in anaerobic or aerobic media after 48h fermentation. The maximum endotoxin concentration in the SIW medium was 435μg/mL, whereas, in anaerobic and aerobic effluent, the maximum concentrations were at 161 μg/mL and 136 μg/mL, respectively. When acidic treatment was performed at pH 2 for these substrates, entomotoxicity obtained from aerobic and anaerobic biopesticide formulations displayed significantly higher entomoxicity than the untreated ones. The entomotoxicity of SIW treated at pH 2 was equivalent to the standard Foray 76B which is 20,000 IU/μL. Anaerobic and aerobic effluent did not contain enough total organic carbon to augment Btk growth and entomotoxicity. Substrates pre-treated at pH 2 provided significant organic matter for Btk growth and resulted in larval mortality equivalent to the com ercial biopesticide Foray 76B.