Effects of high-temperature stress and heat shock on two root maggots, Bradysia odoriphaga and Bradysia difformis (Diptera: Sciaridae)

Bradysia odoriphaga and B. difformis (Diptera: Sciaridae) are devastating pests of vegetables, ornamentals and edible mushrooms. In Chinese chive fields, the two Bradysia species occur with similar regularities: outbreaks in spring and autumn, and population decreases in summer. Temperature may be an important factor restricting their population abundance in summer. Here, we performed a life-table study under constant high temperatures and assessed the tolerance of two Bradysia species to heat shock. Life parameters of the Bradysia species indicated slow developmental rates, and low survival rates and fecundity, when the temperature was higher than 30 °C. At 34 °C, individuals were unable to reach the adult stages from eggs. Moreover, temperatures above 36 °C showed lethal effects, decreasing their survival rates. The median lethal time (LT50) values of 4th instar B. odoriphaga and B. difformis larvae were 46.82 and 32.97 h, respectively, while the values at 38 °C were 2.12 and 1.51 h, respectively. The 4th instar larvae and pupae possessed higher thermotolerance levels than adults and eggs, indicating sensitivities to heat stress. Moreover, B. odoriphaga was more thermotolerant than B. difformis. Thus, weak thermotolerance levels may restrict their occurrences during the period of summer heat, and the difference in thermotolerance levels between the two species may be related to their regional distributions.     

Effects of varying temperature on the reproduction and damage potential of Heterodera schachtii to Chinese cabbage (Brassica rapa pekinensis)

Heterodera schachtii is a well-known, destructive pathogen of Chinese cabbage (Brassica rapa pekinensis) in Korea, and several studies have attempted to find a potential control measure against it. This study is the first to investigate the effects of varying temperature on the reproduction and damage potential of H. schachtii to Chinese cabbage. Chinese cabbage plants were inoculated with H. schachtii at different densities (1, 2, or 4 juveniles per gram of soil) and grown under three temperature regimes: constant (15, 20, or 25 °C), increasing (10, 14, and 18 °C), and fluctuating (positive, 16.7–22.0 °C; negative, 21.5–11.5 °C). At a constant temperature after 30 days of inoculation, both Chinese cabbage and H. schachtii performed best at 20 °C. However, after 60 days of inoculation, H. schachtii had a significantly higher population at 20 °C, whereas cabbage growth was best at 25 °C. With increasing temperature, the numbers of cysts and females did not change significantly, and reached maxima at an initial temperature of 14 °C. However, the number of leaves and weights of the Chinese cabbage plants significantly differed at 14 °C. Under fluctuating temperatures, temperature decreases reduced the H. schachtii population.     

Bacillus onubensis sp. nov., isolated from the air of two Andalusian caves

Two Gram-positive, catalase-positive, oxidase-negative, motile, endospore-forming, rod-shaped bacteria, designated as 0911MAR22V3T and 0911TES10J4, were isolated from air samples collected in two show caves, located in Andalusia, Southern Spain. Phylogenetic analysis based on 16S rRNA gene sequences indicated that both strains were indistinguishable and they were most closely related to Bacillus humi DSM 16318T (98%). DNA–DNA hybridization values of the strain 0911MAR22V3T with respect to strain 0911TES10J4 and B. humi DSM 16318T were 76.8% (73.9%, reciprocal) and 56.9% (63.3%, reciprocal analysis), respectively. Whole genome average nucleotide identity (ANI) values of both strains were in the threshold value for species delineation and less than 85% with B. humi. Strains 0911MAR22V3T and 0911TES10J4 grew at 10–47 °C (optimum 37 °C), at pH 6–9.5 and with 0–8% (w/v) NaCl (optimum 1%). In both strains the dominant isoprenoid quinone was MK-7, the major cellular polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and two more phospholipids, the predominant fatty acids were iso-C15:0 and anteiso-C15:0 and the DNA G + C content was 38 mol%. On the basis of their phylogenetic relatedness and their phenotypic and genotypic features, the strains 0911MAR22V3T and 0911TES10J4 should be attributed to a novel species within the genus Bacillus, for which the name Bacillus onubensis sp. nov. is proposed. The type strain is 0911MAR22V3T (=LMG 27963T = CECT 8479T); and strain 0911TES10J4 (CECT 8478) is a reference strain.     

Proteomic analysis of the adaptation to warming in the Antarctic bacteria Shewanella frigidimarina

Antarctica is subjected to extremely variable conditions, but the importance of the temperature increase in cold adapted bacteria is still unknown. To study the molecular adaptation to warming of Antarctic bacteria, cultures of Shewanella frigidimarina were incubated at temperatures ranging from 0 °C to 30 °C, emulating the most extreme conditions that this strain could tolerate. A proteomic approach was developed to identify the soluble proteins obtained from cells growing at 4 °C, 20 °C and 28 °C. The most drastic effect when bacteria were grown at 28 °C was the accumulation of heat shock proteins as well as other proteins related to stress, redox homeostasis or protein synthesis and degradation, and the decrease of enzymes and components of the cell envelope. Furthermore, two main responses in the adaptation to warm temperature were detected: the presence of diverse isoforms in some differentially expressed proteins, and the composition of chaperone interaction networks at the limits of growth temperature. The abundance changes of proteins suggest that warming induces a stress situation in S. frigidimarina forcing cells to reorganize their molecular networks as an adaptive response to these environmental conditions.     

Clostridium difficile survives minimal temperature recommended for cooking ground meats

We quantified the thermal inhibitory effect of 71 °C (recommended for cooking ground meats), and re-heating at 85 °C, on food- and food-animal-derived Clostridium difficile spores. All C. difficile strains tested (n = 20) survived 71 °C for 2 h, but 90% died within 10 min when re-heated at 85 °C. Current cooking recommendations would need revision to include C. difficile.     

Rising temperatures may increase growth rates and microcystin production in tropical Microcystis species

Rising temperatures (1.4–6 °C) due to climate change have been predicted to increase cyanobacterial bloom occurrences in temperate water bodies; however, the impacts of warming on tropical cyanobacterial blooms are unknown. We examined the effects of four different temperatures on the growth rates and microcystin (MC) production of five tropical Microcystis isolates (M. ichthyoblabe (two strains), M. viridis, M. flos-aquae, and M. aeruginosa). The temperature treatments are based on current temperature range in Singapore's reservoirs (27 °C and 30 °C), as well as projected mean (33 °C) and maximum temperatures (36 °C) based on tropical climate change estimates of +6 °C in air temperature. Increasing temperatures did not significantly affect the maximum growth rates of most Microcystis strains. Higher growth rates were only observed in one M. ichthyoblabe strain at 33 °C and M. flos-aquae at 30 °C where both were isolated from the same reservoir. MC-RR and MC-LR were produced in varying amounts by all four species of Microcystis. Raised temperatures of 33 °C were found to boost total MC cell quota for three Microcystis strains although further increase to 36 °C led to a sharp decrease in total MC cell quota for all five Microcystis strains. Increasing temperature also led to higher MC-LR:MC-RR cell quota ratios in M. ichthyoblabe. Our study suggests that higher mean water temperatures resulting from climate change will generally not influence growth rates of Microcystis spp. in Singapore except for increases in M. ichthyoblabe strains. However, toxin cell quota may increase under moderate warming scenarios depending on the species.     

Bifidobacterium primatium sp. nov., Bifidobacterium scaligerum sp. nov., Bifidobacterium felsineum sp. nov. and Bifidobacterium simiarum sp. nov.: Four novel taxa isolated from the faeces of the cotton top tamarin (Saguinus oedipus) and the emperor tamarin (Saguinus imperator)

Four novel Gram-stain-positive, non spore forming and fructose-6-phosphate phosphoketolase-positive strains were isolated from the faeces of a cotton top tamarin (Saguinus oedipus) and an emperor tamarin (Saguinus imperator). Phylogenetic analyses based on 16S rRNA revealed that bifidobacterial strains TRE 1^T exhibit close phylogenetic relatedness to Bifidobacterium catulorum DSM 103154 (96.0%) and Bifidobacterium tissieri DSM 100201 (96.0%); TRE D^T and TRE H^T were closely related to Bifidobacterium longum subsp. longum ATCC 15708^T with similarity values of 97.4% and 97.5%, respectively; TRI 7^T was closely related to Bifidobacterium tissieri DSM 100201 (96.0%). The Average Nucleotide Identity (ANI) and in silico DDH (isDDH) analysis with closest neighbour supported an independent phylogenetic position of all strains with values ranged from 74 to 85% for ANI and from 24 to 28% for isDDH. DNA base composition of the four strains was in the range of 58.3–63.5 mol% G + C. Based on the phylogenetic, genotypic and phenotypic data, the strains TRE 1^T, TRE D^T, TRE H^T and TRI 7^T clearly represent four novel taxa within the genus Bifidobacterium for which the names Bifidobacterium primatium sp. nov. (type strain TRE 1^T = DSM 100687^T = JCM 30945^T), Bifidobacterium scaligerum sp. nov. (type strain TRE D^T = DSM 103140^T = JCM 31792^T), Bifidobacterium felsineum sp. nov. (type strain TRE H^T = DSM 103139^T = JCM 31789^T) and Bifidobacterium simiarum sp. nov. (type strain TRI 7^T = DSM 103153^T = JCM 31793) are proposed.     

Regulation of Shigella Effector Kinase OspG through Modulation of Its Dynamic Properties

Gram-negative pathogens secrete effector proteins into human cells to modulate normal cellular processes and establish a bacterial replication niche. Shigella and pathogenic Escherichia coli possess homologous effector kinases, OspG and NleH1/2, respectively. Upon translocation, OspG but not NleH binds to ubiquitin and a subset of E2 ~ Ub conjugates, which was shown to activate its kinase activity. Here we show that OspG, having a minimal kinase fold, acquired a novel mechanism of regulation of its activity. Binding of the E2 ~ Ub conjugate to OspG not only stimulates its kinase activity but also increases its optimal temperature for activity to match the human body temperature and stabilizes its labile C-terminal domain. The melting temperature (T_m) of OspG alone is only 31?°C, as compared to 41?°C to NleH1/2 homologs. In the presence of E2 ~ Ub, the T_m of OspG increases to ~ 42?°C, while Ub by itself increases the T_m to 39?°C. Moreover, OspG alone displays maximal activity at 26?°C, while in the presence of E2 ~ Ub, maximal activity occurs at ~ 42?°C. Using NMR and molecular dynamics calculations, we have identified the C-terminal lobe and, in particular, the C-terminal helix, as the key elements responsible for lower thermal stability of OspG as compared to homologous effector kinases.     

Calorimetric and spectroscopic investigations of the thermal denaturation of wild type nitrite reductase

Nitrite reductase (NiR) is a multicopper protein, with a trimeric structure containing two types of copper site: type 1 is present in each subunit whereas type 2 is localized at the subunits interface. The paper reports on the thermal behaviour of wild type NiR from Alcaligenes faecalis S-6. The temperature-induced changes of the copper centres are characterized by optical spectroscopy and electron paramagnetic resonance spectroscopy, and by establishing the thermal stability by differential scanning calorimetry. The calorimetric profile of the enzyme shows a single endothermic peak with maximum heat absorption at T_m ≈ 100 °C, revealing an exceptional thermal stability. The thermal transition is irreversible and the scan rate dependence of the calorimetric trace indicates that the denaturation of NiR is kinetically controlled. The divergence of the activation energy values determined by different methods is used as a criterion for the inapplicability of the one-step irreversible model. The best fit of the DSC profiles is obtained when the classical Lumry–Eyring model, N ? U ? F, is considered. The simulation results indicate that the irreversible step prevails on the reversible one. Moreover, it is found that the conformational changes within the type-1 copper environments precede the denaturation of the whole protein. No evidence of protein dissociation within the temperature range investigated was observed.     

Temperature and dose effects on the pathogenicity and reproduction of two Korean isolates of Heterorhabditis bacteriophora (Nematoda: Heterorhabditidae)

Out of some isolated Heterorhabditis bacteriophora from Korea, ecological study on two isolates which had different geographical features was investigated. That is, effects of temperature and dose on the pathogenicity and reproduction of two Korean isolates of H. bacteriophora were investigated using Galleria mellonella larvae in the laboratory. The median lethal dose (LD₅₀) decreased with increasing temperature, but increased at 35 °C. The optimal temperatures for infection were 30 °C for H. bacteriophora Jeju strain and 24 °C for H. bacteriophora Hamyang strain. The median lethal time, LT₅₀ of H. bacteriophora Hamyang strain was recorded at 13 °C to 35 °C and that of H. bacteriophora Jeju strain was recorded at 18 °C to 30 °C. The number of established nematodes in G. mellonella larvae was significantly different depending on temperature and dose. When G. mellonella larvae were exposed to 300 infective juveniles (IJs), mortality of G. mellonella gradually increased with exposure time with H. bacteriophora Jeju strain but not with H. bacteriophora Hamyang strain. 87.5% mortality of G. mellonella was recorded by H. bacteriophora Hamyang strain after 1440 min whereas 100% mortality was recorded by H. bacteriophora Jeju strain after 4320 min. The time from infection to the first emergence of nematodes decreased with increasing temperature. Duration of emergence of the two strains in the White traps also decreased with increasing temperature. The highest progeny numbers of H. bacteriophora Jeju strain were 264,602 while those of H. bacteriophora Hamyang strain were 275,744 at the rate of 160 IJs at 24 °C.     

Temperature-dependent development and oviposition models of Leptocorisa chinensis Dallas (Hemiptera: Alydidae)

Leptocorisa chinensis Dallas (Hemiptera: Alydidae) is known to cause pecky rice by sucking panicles of milk stage of rice. Based on its continuous spread and expanded damage area in Asian countries such as Japan with high reproduction potential, it is highly likely that L. chinensis will become an important rice pest in the near future. However, limited information is available to predict its distribution and occurrence. Thus, the objective of this study was to develop models for their development and oviposition. We investigated the development of L. chinensis immatures (from egg to adult) at 11 constant temperatures ranging from 16.2 to 35.3 °C and the oviposition of female adults at five constant temperatures ranging from 22.3 to 35.3 °C in this study. For L. chinensis immatures, the lower developmental threshold temperature, optimal developmental temperature, upper developmental threshold temperature were 12.7, 32.3, and 37.6 °C, respectively. The highest survival rate of immatures was observed at temperature of 25.2 °C and the highest mean total fecundity was 585.8 at 28.0 °C. This study provides basic information for the ecology of L. chinensis. It is applicable to forecast the phenology of its populations in the fields and to predict its future distribution under global warming.     

Formulation of Pseudomonas chlororaphis strains for improved shelf life

Formulations of Pseudomonas strains with long-term shelf life are needed for commercial use in biological disease control and growth promotion in crops. In the present work Pseudomonas chlororaphis (Pc) 63-28 formulated with coconut fiber [moisture content (MC) of 80%], talc (MC 8%) or peat (MC 40%), with or without the addition of carboxymethylcellulose or xanthan gum, and formulations of Pc 63-28 and P. chlororaphis TX-1 in coconut fiber with water contents (v:v) of 75%, 45%, and 25%, were evaluated in terms of shelf life and cell viability. The shelf life of Pc 63-28 was longer when formulated in coconut fibre with a MC was 80% than in the other formulations and longer at 3 ± 1 °C compared to 22 ± 1 °C. Densities of viable Pc 63-28 cells in coconut fiber stored at 3 ± 1 °C did not decline significantly during 224 days when the MC was 80% and within 120 days at 75% MC. Densities of Pc TX-1 in coconut fiber of 75% MC did not decline within 60 days at 3 ± 1 °C. P. chlororaphis 63-28 survived longer in deionized water and buffer than in canola oil. Cells of Pc 63-28 cells formulated in coconut fibre of 80% MC after storage for 140 days at 3 ± 1 °C in coconut fiber improved hydroponic growth of hydroponic lettuce and better than cells freshly recovered from culture. We conclude that coconut fiber is a carrier of superior performance in maintaining shelf life of Pseudomonas strains. The observed shelf life would be sufficient for practical use of Pseudomonas strains as tools for disease control and growth promotion in crops.     

Tetracycline-resistant bacteria as indicators of antimicrobial resistance in protected waters—The example of the Drwęca River Nature Reserve (Poland)

The objective of this study was to determine the suitability of Tet^R tetracycline-resistant bacteria as potential indicators of drug resistance, a parameter of the microbiological quality of river waters in natural reserves which are threatened by man-made pollution. The microbiological assays covered a 15-km long section of the upper reach of the Drw?ca River (Poland), a part of the European Ecological “Natura 2000” Network of nature protected areas. The quality of the investigated ecosystem was affected by surface runoffs from the river's agricultural catchment as well as outflows from three fish farms. The counts of Tet^R bacteria, incubated at 14 °C and 28 °C on TSA medium with sheep blood and tetracycline, were determined in river water samples. The highest counts of both bacterial groups were determined in samples collected from sites behind fish farms. A statistical analysis of the abundance of Tet^R14 °C and Tet^R28 °C bacteria revealed significant differences in the size of Tet^R28 °C populations at the studied sampling sites (p = 0.0011), which is why hemolytic bacteria of this group (HemTet^R28 °C) were selected for further investigations. The predominant strains in the group of 86 HemTet^R28 °C isolates obtained by 16S rRNA gene sequencing were Pseudomonas fluorescens (42 isolates) and Aeromonas hydrophila (28 isolates). Analyses of the identified HemTet^R28 °C strains demonstrated MIC ≥256 μg/ml in more than 50% isolates. The MAR index of HemTet^R28 °C was in the range of 0.67 at the control site to 1 at sites behind fish farms. The results suggest that tetracycline-resistant bacteria, in particular HemTet^R28 °C, are a reliable indicator of antimicrobial resistance and the microbial quality of surface waters polluted due to human activity. The above can be attributed to several factors: (I) the highest percentage share of HemTet^R28 °C among HPC28 °C was noted at sites behind fish farms, (II) tetracycline-resistant bacteria quickly respond to environmental changes, as demonstrated by the high level of resistance to tetracycline and a very high MAR index, and (III) genera/species that are easy to culture under laboratory conditions dominate in the qualitative and quantitative composition of the studied bacteria.     

Paenibacillus ihbetae sp. nov., a cold-adapted antimicrobial producing bacterium isolated from high altitude Suraj Tal Lake in the Indian trans-Himalayas

The assessment of bacterial diversity and bioprospection of the high-altitude lake Suraj Tal microorganisms for potent antimicrobial activities revealed the presence of two Gram-stain-variable, endospore-forming, rod-shaped, aerobic bacteria, namely IHBB 9852^T and IHBB 9951. Phylogenetic analysis based on 16S rRNA gene sequence showed the affiliation of strains IHBB 9852^T and IHBB 9951 within the genus Paenibacillus, exhibiting the highest sequence similarity to Paenibacillus lactis DSM 15596^T (97.8% and 97.7%) and less than 95.9% similarity to other species of the genus Paenibacillus. DNA-DNA relatedness among strains IHBB 9852^T and IHBB 9951 was 90.2%, and with P. lactis DSM 15596^T, was 52.7% and 52.4%, respectively. The novel strains contain anteiso-C_15:0, iso-C_15:0, C_16:0 and iso-C_16:0 as major fatty acids, and phosphatidylglycerol, phosphatidylethanolamine and diphosphatidylglycerol were predominant polar lipids. The DNA G+C content for IHBB 9852T and IHBB 9951 was 52.1 and 52.2 mol%. Based on the results of phenotypic and genomic characterisations, we concluded that strains IHBB 9852^T and IHBB 9951 belong to a novel Paenibacillus species, for which the name Paenibacillus ihbetae sp. nov. is proposed. The type strain is IHBB 9852^T (=MTCC 12459^T = MCC 2795^T = JCM 31131^T = KACC 19072^T; DPD TaxonNumber TA00046) and IHBB 9951 (=MTCC 12458 = MCC 2794 = JCM 31132 = KACC 19073) is a reference strain.     

Enrichment and physiological characterization of an anaerobic ammonium-oxidizing bacterium ‘Candidatus Brocadia sapporoensis’

We successfully enriched a novel anaerobic ammonium-oxidizing (anammox) bacterium affiliated with the genus ‘Candidatus Brocadia’ with high purity (>90%) in a membrane bioreactor (MBR). The enriched bacterium was distantly related to the hitherto characterized ‘Ca. Brocadia fulgida’ and ‘Ca. Brocadia sinica’ with 96% and 93% of 16S ribosomal RNA gene sequence identity, respectively. The bacterium exhibited the common structural features of anammox bacteria and produced hydrazine in the presence of hydroxylamine under anoxic conditions. The temperature range of anammox activity was 20–45 °C with a maximum activity at 37 °C. The maximum specific growth rate (μ_max) was 0.0082 h^?1 at 37 °C, corresponding to a doubling time of 3.5 days. The half-saturation constant (K_S) for nitrite was 5 ± 2.5 μM. The anammox activity was inhibited by nitrite (IC₅₀ = 11.6 mM) but not by formate and acetate. The major respiratory quinone was identified to be menaquinone-7 (MK-7). The enriched anammox bacterium shared nearly half of genes with ‘Ca. Brocadia sinica’ and ‘Ca. Brocadia fulgida’. The enriched bacterium showed all known physiological characteristics of anammox bacteria and can be distinguished from the close relatives by its 16S rRNA gene sequence. Therefore, we proposed the name ‘Ca. Brocadia sapporoensis’ sp. nov.     

Physiological responses of Ostreopsis ovata to changes in N and P availability and temperature increase

Ostreopsis ovata is a benthic dinoflagellate that produces palytoxin and ovatoxins. Blooms of O. ovata causing human health problems and mortality of benthic fauna have been reported from many tropical and temperate marine waters. In the present study we examined the combined effects of temperature and different nutrient conditions on the biochemical composition, growth, toxicity and carbohydrate production of an O. ovata strain originating from the Tyrrhenian Sea. O. ovata cultures with N:P ratios of 1.6, 16 and 160 (N deficient, NP sufficient and P deficient, respectively) were grown at 20 °C and 30 °C. Biomass accumulation, growth rates, cell volumes, biochemical composition, cell toxicity and carbohydrate production in each treatment were studied. Results indicated that under nutrient sufficiency O. ovata biomass accumulation increased significantly compared to N and P deficiency and also that N limitation severely affected growth. The highest growth rates were recorded at 30 °C. Cellular contents and the atomic ratios of C, N and P were higher in the cells grown at 20 °C than in those grown at 30 °C. O. ovata cell volumes increased at 20 °C. N deficiency significantly increased cell toxicity. Toxicity per cell was higher at 20 °C, but per carbon was highest at 30 °C. The highest carbohydrate production was found in conditions of N deficiency and at the lower temperature.Our study suggests that temperature increases due to global warming and nutrient enrichment of coastal waters stimulate the proliferation of O. ovata, particularly for the strains that have become adapted to warm temperate waters.     

Phenotypic and genetic diversity of Moroccan rhizobia isolated from Vicia faba and study of genes that are likely to be involved in their osmotolerance

Rhizobia are symbiotic nitrogen-fixing bacteria in root nodules of legumes. In Morocco, faba bean (Vicia faba L.), which is the main legume crop cultivated in the country, is often grown in marginal soils of arid and semi-arid regions. This study examines the phenotypic diversity of rhizobia nodulating V. faba isolated from different regions in Morocco for tolerance to some abiotic stresses. A total of 106 rhizobia strains isolated from nodules were identified at the species level by analysing 16S rDNA. Additionally, for selected strains recA, otsA, kup and nodA fragments were sequenced. 102 isolates are likely to belong to Rhizobium leguminosarum or R. laguerreae and 4 isolates to Ensifer meliloti. All strains tolerating salt concentrations of 428 or 342 mM NaCl as well as 127 or 99 mM Na2SO4 were highly resistant to alkaline conditions (pH 10) and high temperature (44 °C). Three strains: RhOF4 and RhOF53 (both are salt-tolerant) and RhOF6 (salt-sensitive) were selected to compare the influence of different levels of salt stress induced by NaCl on growth and on trehalose and potassium accumulation. We find a direct correlation between the trehalose contents of the rhizobial strains and their osmotolerance.     

Hydrolysis of nitriles and amides by filamentous fungi

Screening of culture collection afforded nitrile-utilizing fungi belonging to genera Aspergillus, Talaromyces and Penicillium. Fusarium solani O1 was enriched from soil using 3-cyanopyridine as the sole source of nitrogen. This strain, and Penicillium multicolor CCF 2244 (the best one of the culture collection strains), showed comparable specific benzonitrile-hydrolyzing activities (0.95 and 0.87 μmol of benzoic acid h⁻¹ mg⁻¹ of dry cell weight at 28 °C, respectively). These fungi showed similar substrate specificities for substituted benzonitriles and heterocyclic nitriles but different pH and temperature optima (pH 8 and 38 °C for P. multicolor, pH 7 and 48 °C for F. solani). Amides as by-products were produced from some heterocyclic nitriles. Both fungi showed an amidase activity for nicotinamide.