Effect of temperature on vegetative growth among isolates of Metarhizium anisopliae and M. flavoviride

Effects of temperature on vegetative growth on a semi-synthetic medium of 22 isolates of Metarhizium anisopliae and 14 isolates of M. flavoviride were determined. The majority of isolates of both species grew between 11 and 32°C; several isolates grew at 8 and 37 °C. None of the isolates grew at 40 °C. Relative growth rate, calculated from the maximum growth rate for each isolate, was significantly affected by temperature and isolate, with significant isolate * temperature interactions. The maximum absolute growth rates among the isolates ranged from 2.5 mm to 5.9 mm/day. Optimal temperatures were generally between 25 and 32 °C with several isolates exhibiting optimal growth at temperatures as high as 32 °C. Overall, relative growth rates were greater in isolates of M. anisopliae than M. flavoviride at temperatures of 25 °C or lower; conversely mean relative growth rates were greater in M. flavoviride than M. anisopliae at temperatures higher than 25 °C. However, the two most cold tolerant isolates at 8 °C were M. flavoviride and the three most heat tolerant at 35 °C were M. anisopliae. Since temperature growth responses varied considerably between isolates, strain selection according to thermal tolerance may be warranted when choosing a strain for development as a microbial control agent.This revised version was published online in October 2005 with corrections to the Cover Date.     

Heliobacterium modesticaldum,sp. nov., a thermophilic heliobacterium of hot springs and volcanic soils

Enrichment cultures for heliobacteria at 50°C yielded several strains of a thermophilic heliobacterium species from Yellowstone hot spring microbial mats and volcanic soils from Iceland. The novel organisms grew optimally above 50°C, contained bacteriochlorophyll g, and lacked intracytoplasmic membranes. All isolates were strict anaerobes and grew best as photoheterotrophs, although chemotrophic dark growth on pyruvate was also possible. These thermophilic heliobacteria were diazotrophic and fixed N₂ up to their growth temperature limit of 56°C. Phylogenetic studies showed the new isolates to be specific relatives of Heliobacterium gestii and, as has been found in H. gestii, they produce heat-resistant endospores. The unique assemblage of properties found in these thermophilic heliobacteria implicate them as a new species of this group, and we describe them herein as a new species of the genus Heliobacterium, Heliobacterium modesticaldum.     

Degradation of 2,3,4,6-tetrachlorophenol at low temperature and low dioxygen concentrations by phylogenetically different groundwater and bioreactor bacteria

Effects of low temperature and low oxygen partial pressure on theoccurrence and activity of 2,3,4,6-tetrachlorophenol degrading bacteria in a boreal chlorophenol contaminated groundwater and a full-scale fluidized-bed bioreactor were studied using four polychlorophenol degrading bacterial isolates of different phylogenetic backgrounds. These included an -proteobacterial Sphingomonas sp. strain MT1 isolated from the full-scale bioreactor and three isolates from the contaminated groundwater whichwere identified as -proteobacterial Herbaspirillum sp. K1,a Gram-positive bacterium with high G + C content Nocardioides sp. K44 and an -proteobacterialSphingomonas sp. K74. The Sphingomonasstrains K74 and MT1 and Nocardioides sp. K44 degraded2,4,6-trichlorophenol and 2,3,4,6-tetrachlorophenol as the solecarbon and energy sources. Close to stoichiometric inorganic chloride release with the 2,3,4,6-tetrachlorophenol removal andthe absence of methylation products indicated mineralization. Tetrachlorophenol degradation by the Herbaspirillum sp. K1 was enhanced by yeast extract, malate, glutamate, pyruvate, peptone and casitone. At 8 °C, Sphingomonas sp. K74 had the highest specific degradation rate(_max = 4.9 × 10^-12 mg h^-1 cell^-1) for 2,3,4,6-tetrachlorophenol. The Nocardioides strain K44 had the highest affinity (K_s = 0.46 mg l^-1) for tetrachlorophenol. K1 and MT1 grew microaerophilically in semisolid glucose medium. Furthermore, the growth of MT1 was inhibited in liquidglucose medium at high oxygen partial pressure indicating sensitivity to accumulating toxic oxygen species. On the other hand, trichlorophenol degradation was not affected by oxygen concentration (2–21%). The isolates K44, K74 and MT1, with optimum growth temperaturesbetween 23 and 25 °C, degraded tetrachlorophenol faster at 8 °C than at room temperature indicating distinctly different temperature optima for chlorophenol degradation and growthon complex media. These results show efficient polychlorophenol degradation by the isolates at the boreal groundwater conditions, i.e., at low temperature and low oxygen concentrations. Differences in chlorophenol degradation and sensitivities to chlorophenols and oxygen among the isolates indicate that the phylogenetically different chlorophenol degraders have found different niches in the contaminated groundwater and thus potential for contaminantdegradation under a variety of saturated subsurface conditions.     

Effect of constant temperatures on germination, radial growth and virulence of Metarhizium anisopliae to three species of African tephritid fruit flies

The effect of temperatureon conidial germination, mycelial growth, andsusceptibility of adults of three tephritidfruit flies, Ceratitis capitata(Wiedemann), C. fasciventris (Bezzi) andC. cosyra (Walker) to six isolatesof Metarhizium anisopliae were studied inthe laboratory. There were significantdifferences among the isolates in the effect oftemperature on both germination and growth.Over 80% of conidia germinated at 20, 25 and30°C, while between 26 and 67% conidiagerminated at 35°C and less than 10% at15°C within 24 hours. Radial growth was slowat 15°C and 35°C with all of theisolates. The optimum temperature forgermination and mycelial growth was 25°C. Mortality caused by the six fungal isolatesagainst the three fruit fly species varied withtemperature, isolate, and fruit fly species.Fungal isolates were more effective at 25, 30and 35°C than at 20°C. The LT₉₀values decreased with increasing temperature upto the optimum temperature of 30°C. Therewere significant differences in susceptibilitybetween fly species to fungal infection at allthe temperatures tested.     

Effects of temperature on growth rates of fungi from subantarctic Macquarie Island and Casey,Antarctica

Summary The linear growth rates of fungal isolates were measured on agar plates at temperatures ranging from 4° to 35°C. Fungi tested included the major fungal colonizers of leaves and litter of the three dominant plant species on subantarctic Macquarie Island, and major fungal species associated with plant and soil communities near Australia's Casey Station on the Antarctic Continent. All fungi grew at 4°C and were classified as psychrotrophs. Maximum growth rates were recorded at temperatures of 10° to 20°C for 13 of the 15 isolates from Macquarie Island and for all six isolates from Casey. Most of the leaf colonizing fungi from Macquarie Island had optimum growth temperatures of 15°C whereas all litter fungi from Macquarie Island and Casey fungi except Thelebolus microsporus had optimum growth temperatures of 20°C or above. Maximum growth of all species was at temperatures above those normally prevailing in their natural environments, with most species growing at 4°C at between 10% and 30% of their maximum rates. However, microclimatic effects may have resulted at times in temperatures near their growth optima. The highest growth rates at 4°C were recorded for Phoma spp. 1 and 2, Phoma exigua and Mortierella gamsii from Macquarie Island and Mortierella sp. 1 from Casey. Thelebolus microsporus and sterile sp. G from Casey also grew relatively fast at 4°C, and these species, and Phoma sp. 3 and Phoma exigua from Macquarie Island had the lowest Q-₁₀ values for the temperature range 4° to 15°C.     

Xylanolytic anaerobic thermophiles from Icelandic hot-springs

Anaerobic enrichment cultures inoculated with neutral and alkaline (pH 7.0–9.0) sediment and biomat samples from hot-springs in Hveragerdi and Fluir, Iceland, were screened for growth on beech xylan from pH 8.0 to 10.0 at 68° C: no growth occured in cultures above pH 8.4. Five anaerobic xylanolytic bacteria were isolated from enrichment cultures at pH 8.4; all five microbes were Gram-positive rods with terminal spores, and produced CO₂, H₂, acetate, lactate and ethanol from xylan and xylose. One of the isolates, strain A2, grew from 50 to 75° C, with optimum growth near 68° C, and from pH 5.2 to 9.0 with an optimum between 6.8 and 7.4. Taxonomically, strain A2 was most similar to Clostridium thermohydrosulfuricum. At pH 7.0, the supernatant xylanases of strain A2 had a temperature range from 50 to 78° C with an optimum between 68 and 78° C. At 68° C, xylanase activity occurred from pH 4.9 to 9.1, with an optimum from pH 5.0 to 6.6. At pH 7.0 and 68° C, the K _m of the supernatant xylanases was 2.75 g xylan/l and the V _max was 2.65 × 10^–6 kat/l culture supernatant. When grown on xylose, xylanase production was as high as when grown on xylan. Correspondence to: B. K. Ahring     

Thiobacillus plumbophilus spec. nov., a novel galena and hydrogen oxidizer

From an uranium mine three strains of rodshaped, mesophilic, chemolithoautotrophic bacteria were isolated. They grow by oxidation of H₂S, galena (PbS) and H₂. Anglesite (PbSO₄) is formed from galena. No ferrous iron is oxidized by the isolates. They grow between pH 4 and 6.5 at temperatures of about 9 to 41°C (optimum around 27°C). The G+C content of the DNA is around 66 mol %. Based on their ability to oxidize sulfur compounds, the new organisms belong to the genus Thiobacillus. No significant homology with Thiobacillus ferrooxidans and Thiobacillus cuprinus was detected by DNA-DNA hybridization. Therefore the new isolates represent a new species within the genus Thiobacillus. Based on the unusual growth on galena, we name the new species Thiobacillus plumbophilus (type strain Gro 7; DSM 6690).     

Thermosediminibacter oceani gen. nov., sp. nov. and Thermosediminibacter litoriperuensis sp. nov., new anaerobic thermophilic bacteria isolated from Peru Margin

A new group of anaerobic thermophilic bacteria was isolated from enrichment cultures obtained from deep sea sediments of Peru Margin collected during Leg 201 of the Ocean Drilling Program. A total of ten isolates were obtained from cores of 1–2 m below seafloor (mbsf) incubated at 60°C: three isolates came from the sediment 426 m below sea level with a surface temperature of 9°C (Site 1227), one from 252 m below sea level with a temperature of 12°C (Site 1228), and six isolates under sulfate-reducing condition from the lower slope of the Peru Trench (Site 1230). Strain JW/IW-1228P from the Site 1228 and strain JW/YJL-1230-7/2 from the Site 1230 were chosen as representatives of the two identified clades. Based on the 16S rDNA sequence analysis, these isolates represent a novel group with Thermovenabulum and Caldanaerobacter as their closest relatives. The temperature range for growth was 52–76°C with an optimum at around 68°C for JW/IW-1228P and 43–76°C with an optimum at around 64°C for JW/YJL-1230-7/2. The pH^25C range for growth was from 6.3 to 9.3 with an optimum at 7.5 for JW/IW-1228P and from 5 to 9.5 with an optimum at 7.9–8.4 for JW/YJL-1230-7/2. The salinity range for growth was from 0% to 6% (w/v) for JW/IW-1228P and from 0% to 4.5% (w/v) for JW/YJL-1230-7/2. The G+C content of the DNA was 50 mol% for both JW/IW-1228P and JW/YJL-1230-7/2. DNA–DNA hybridization yielded 52% similarity between the two strains. According to 16S rRNA gene sequence analysis, the isolates are located within the family, Thermoanaerobacteriaceae. Based on their morphological and physiological properties and phylogenetic analysis, it is proposed that strain JW/IW-1228P^T is placed into a novel taxa, Thermosediminibacter oceani, gen. nov., sp. nov. (DSM 16646^T=ATCC BAA-1034^T), and JW/YJL-1230-7/2^T into Thermosediminibacter litoriperuensis sp. nov. (DSM 16647^T =ATCC BAA-1035^T).An erratum to this article can be found at     

Cultivated anaerobic acidophilic/acidotolerant thermophiles from terrestrial and deep-sea hydrothermal habitats

Metabolic and phylogenetic diversity of cultivated anaerobic microorganisms from acidic continental hot springs and deep-sea hydrothermal vents was studied by molecular and microbiological methods. Anaerobic organotrophic enrichment cultures growing at pH 3.5–4.0 and 60 or 85°C with organic energy sources were obtained from samples of acidic hot springs of Kamchatka Peninsula (Pauzhetka, Moutnovski Volcano, Uzon Caldera) and Kunashir Island (South Kurils) as well as from the samples of chimneys of East Pacific Rise (13°N). The analyses of clone libraries obtained from terrestrial enrichment cultures growing at 60°C revealed the presence of archaea of genus Thermoplasma and bacteria of genus Thermoanaerobacter. Bacterial isolates from these enrichments were shown to belong to genera Thermoanaerobacter and Thermoanaerobacterium, being acidotolerant with the pH optimum for growth at 5.5–6.0 and the pH minimum at 3.0. At 85°C, domination of thermoacidophilic archaea of genus Acidilobus in terrestrial enrichments was found by both molecular and microbiological methods. Five isolates belonging to this genus possessed some phenotypic features that were new for this genus, such as flagellation or the ability to grow on monosaccharides or disaccharides. Analyses of clone libraries from the deep-sea thermoacidophilic enrichment cultures showed that the representatives of the genus Thermococcus were present at both 60 and 85°C. From the 60°C deep-sea enrichment, a strain belonging to Thermoanaerobacter siderophilus was isolated. It grew optimally at pH 6.0 with the minimum pH for growth at 3.0 and with salinity optimum at 0–2.5% NaCl and the maximum at 7%, thus differing significantly from the type strain. These data show that fermentative degradation of organic matter may occur at low pH and wide temperature range in both terrestrial and deep-sea habitats and can be performed by acidophilic or acidotolerant thermophilic prokaryotes.     

Energetics of growth of Microbacterium thermosphactum at low temperatures

Microbacterium thermosphactum was grown at 5°C and 9°C in glucose-limited continuous cultures. The end products of glucose metabolism were L-lactate and ethanol, and these compounds accounted for 86–92% of the glucose utilized. With input glucose concentrations less than 3 mM Y _glu ^Max was found to be 40–43, Y _ATP ^Max 20–21 and m _s 0.1–0.2. These values are almost identical to those found previously for cultures at 25°C and show that this psychrotroph grows with a very high energetic efficiency over a wide range of temperatures. With a higher (but still limiting) input glucose concentration of 5.6 mM at 9°C, cellular efficiency declined as there was a marked reduction in Y _glu. This decrease was accounted for in mathematical terms by an increase in m _s to 0.7, whilst Y _glu ^Max and Y _ATP ^Max remained high at 38 and 19 respectively.     

Psychrotrophic,lactic acid-producing bacteria from anoxic waters in Ace Lake,Antarctica; Carnobacterium funditum sp. nov. and Carnobacterium alterfunditum sp. nov.

Heterofermentative, lactic acid-producing, gram-positive, motile bacteria were isolated from the waters of Ace Lake, Antarctica. All strains produced virtually only l(+)lactic acid from d(+)glucose. d(–)ribose was fermented to lactic, acetic, and formic acids, and ethanol. Cell walls contained meso-diaminopimaleic acid. The strains did not grow at 30°C and were psychrotrophic. Whole cells contained 18:1cis 9 as a major component of their fatty acids. At 20°C, the strains grew better anaerobically than aerobically and all strains lacked catalase, oxidase and respiratory lipoquinones. DNA that coded for most of the 16S rRNA gene of one of the strains was amplified by the polymerase chain reaction and sequenced. The strain was phylogenetically most closely related to Carnobacterium mobile (K_nuc=0.0214). The isolates separated into two phenotypes. DNA/DNA homology studies determined on a representative from each phenotype showed low homology between the phenotypes (38±8%), and with Carnobacterium mobile (26±2%, 34±2%). Carnobacterium funditum sp. nov. produced acid from mannitol, trehalose, but not amygdalin. The G+C content of the DNA was 32–34%, and the Type strain is DSM 5970 (=ACAM 312). Carnobacterium alterfunditum sp. nov. produced acid weakly from amygdalin but not from mannitol or trehalose. The G+C content was 33–34%, and the Type strain is DSM 5972 (=ACAM 313).     

Diversity and cold-active hydrolytic enzymes of culturable bacteria associated with Arctic sea ice,Spitzbergen

The diversity of culturable bacteria associated with sea ice from four permanently cold fjords of Spitzbergen, Arctic Ocean, was investigated. A total of 116 psychrophilic and psychrotolerant strains were isolated under aerobic conditions at 4°C. The isolates were grouped using amplified rDNA restriction analysis fingerprinting and identified by partial sequencing of 16S rRNA gene. The bacterial isolates fell in five phylogenetic groups: subclasses and of Proteobacteria, the Bacillus–Clostridium group, the order Actinomycetales, and the Cytophaga–Flexibacter–Bacteroides (CFB) phylum. Over 70% of the isolates were affiliated with the Proteobacteria subclass. Based on phylogenetic analysis (<98% sequence similarity), over 40% of Arctic isolates represent potentially novel species or genera. Most of the isolates were psychrotolerant and grew optimally between 20 and 25°C. Only a few strains were psychrophilic, with an optimal growth at 10–15°C. The majority of the bacterial strains were able to secrete a broad range of cold-active hydrolytic enzymes into the medium at a cultivation temperature of 4°C. The isolates that are able to degrade proteins (skim milk, casein), lipids (olive oil), and polysaccharides (starch, pectin) account for, respectively, 56, 31, and 21% of sea-ice and seawater strains. The temperature dependences for enzyme production during growth and enzymatic activity were determined for two selected enzymes, -amylase and -galactosidase. Interestingly, high levels of enzyme productions were measured at growth temperatures between 4 and 10°C, and almost no production was detected at higher temperatures (20–30°C). Catalytic activity was detected even below the freezing point of water (at –5°C), demonstrating the unique properties of these enzymes.     

A comparative study of two Mexican isolates with an Australian isolate of Metarhizium anisopliae var. acridum – strain characterisation, temperature profile and virulence for wingless grasshopper, Phaulacridium vittatum

Three isolates of Metarhiziumanisopliae var. acridum, FI-985,from the spur-throated locust, Austracrisguttulosa from Australia, and QF-01 and QF-02both from Schistocerca piceifrons inMexico were compared. FI-985 had much largerconidia than the other two isolates and alsohad a different colony appearance. The twoMexican isolates showed small differences inconidial size and colony morphology. Over arange of 6 primers, RAPDs patterns were verysimilar in that the two Mexican isolates being identical, and FI-985 having some unique bandsonly with 2 primers. The 3 isolates were alsosimilar in growth profiles on agar plates, andat high temperatures (36°C), QF-01 didnot grow while the other two isolates grewslowly. All three isolates were similar invirulence for wingless grasshoppers, Phaulacridium vittatum, at 20–30°C but at 35°C, FI-985 was the mostvirulent and QF-01 the least over a range of 3doses. At 15°C, FI-985 was also the mostvirulent with QF-02 being least virulent. At30°C, the LD₅₀ at 17 days rangedfrom 248 conidia for QF-02 to 501 conidia forFI-985, however the differences were notsignificant (p > 0.05). It is suggested thatconsideration should be given to using anexotic isolate such as FI-985 as a commerciallocust biopesticide in countries such asMexico, since the isolate is cheap to massproduce, more effective at higher temperaturescommon in tropical to subtropical Mexico, andrelatively resistant to UV.     

Transplasmalemma electron transport is changed in simian virus 40 transformed liver cells

Transplasma membrane electron transport activity by fetal rat liver cells (RLA209-15) infected with a temperature-sensitive strain of SV40 has been measured with cells grown at the restrictive temperature (40°C) and permissive temperature (33°C). The transformed cells grown at 33°C had only one-half the rate of external ferricyanide reduction as the nontransformed cells held at 40°C. Both theK _m andV _max for ferricyanide reduction were changed in the transformed state. The change inV _max can be based on a decrease of NADH in the transformed cells. The change in rate with ferricyanide does not depend on change in surface charge. Reduction of external ferricyanide was accompanied by release of protons from the cells. The ratio of protons released to ferricyanide reduced was higher in the transformed cells than in the non-transformed cells. Since the transplasma membrane electron transport has been shown to stimulate cell growth under limiting serum, the changes in the plasma membrane electron transport and proton release in transformed cells may relate to modification of growth control.     

Geobacillus uralicus,a New Species of Thermophilic Bacteria

The K^T ₂ strain of thermophilic spore-forming bacteria was isolated from a biofilm on the surface of a corroded pipeline in an extremely deep well (4680 m, 40–72°C) in the Urals. The cells are rod-shaped, motile, gram-variable. They grow on a complex medium with tryptone and yeast extract and on a synthetic medium with glucose and mineral salts without additional growth factors. The cells use a wide range of organic substances as carbon and energy sources. They exhibit a respiratory metabolism but are also capable of anaerobic growth on a nitrate-containing medium. Growth occurs within the 40–75°C temperature range (with an optimum of 65°C) and at pH 5–9. The minimum generation time (15 min) was observed at pH 7.5. Ammonium salts, nitrates, and arginine are used as nitrogen sources. The G+C content of the DNA is 54.5 mol %. From the morphological, physiological, and biochemical properties and the nucleotide sequence of the 16S rRNA gene, it was concluded that the isolate K^T ₂ represents a new species of the genus Geobacillus, Geobacillus uralicus.     

Reduction of acetylene by nodules of Trifolium subterraneum as affected by root temperature,Rhizobium strain and host cultivar

Summary The nitrogenase activity (measured by reduction of C₂H₂ to C₂H₄) of nodules of Trifolium subterraneum grown at root temperatures from 7°C–19°C was broadly correlated with nitrogen fixation. Root temperature did not affect enzyme activity per se but did affect the amount of enzyme formed. Exposure of nodules to 7°C for 24 h did not decrease activity cf. 19°C. Activity was greatest when nodules were about 4 days old, before swollen bacteroid forms were produced, and then declined. The effectiveness of a bacterial strain at a given temperature was related to the amount of enzyme produced and to its persistence. Nitrogenase activity should be measured throughout the plant growth cycle for valid comparisons of strain effectiveness.     

Phenotypic characteristics of root-nodulating bacteria isolated from Acacia spp. grown in Libya

Thirty isolates of root-nodulating bacteria obtained from Acacia cyanophylla, A. karroo, A. cyclops, A. tortilis (subsp.raddiana), Faidherbia albida and Acacia sp., grown in different regions of Libya, were studied by performing numerical analysis of 104 characteristics. Three fast- and one slow-growing reference strains from herbaceous and woody legumes were included. Five distinct clusters were formed. The fast-growing reference strains were separated from the isolates whereas the slow-growing was included in cluster 4. With the exception of one cluster, the majority of clusters were formed regardless of the host plant or site of origin. Based on plant tests, generation times, acid production and carbon utilization the isolates were diverse (fast and slow-growing isolates). Like slow-growing isolates, most of the fast-growing isolates appeared to be non-specific, nodulated many species from the same genus notably F. albida, known to nodulate only with slow-growing strains. Most clusters grew at temperatures 35 °C and 37 °C; some grew at temperatures above 40 °C. The majority of isolates grew at acid and alkaline pH and only one isolate grew below pH 4. Most isolates were able to utilize many amino acids as nitrogen sources and to reduce nitrate. Urea was hydrolysed by all clusters. Monosaccharides and polyols were used by slow and fast-growing isolates as the only carbon sources whereas assimilation of disaccharides varied: Some isolates, like slow-growing isolates, failed to utilize these carbon sources. Most isolates were unable to utilize polysaccharides. Regarding tolerance to NaCl on agar medium, the majority of isolates were unable to grow at a concentration of 2% NaCl, but some were highly resistant and there was one isolate which grew at 8% NaCl. Most isolates were resistant to heavy metals and to antibiotics.     

Halonatronum saccharophilum gen. nov. sp. nov.: A New Haloalkaliphilic Bacterium of the Order Haloanaerobiales from Lake Magadi

A new alkaliphilic and moderately halophilic chemoorganotrophic anaerobic bacterium (strain Z-7986), which is spore-forming, rod-shaped, and has a gram-negative cell wall pattern, was isolated from the coastal lagoon mud of the highly mineralized Lake Magadi (Kenya). The organism is an obligatorily carbonate- and sodium chloride-dependent motile peritrichously flagellated rod that grows within a 3–17% NaCl concentration range (with an optimum at 7–12% NaCl) and within a pH range of 7.7–10.3 (with an optimum at pH values of 8–8.5). It is a moderate thermophile with a broad temperature optimum at 36–55°C; maximum growth temperature is 60°C. The bacterium catabolizes glucose, fructose, sucrose, maltose, starch, glycogen, N-acetyl-D-glucosamine, and, to a slight degree, peptone and yeast extract. Its anabolism requires yeast extract or casamino acids. Glucose fermentation yields formate, acetate, ethanol, H₂, and CO₂. The bacterium is sulfide-tolerant and capable of the nonspecific reduction of S⁰ to H₂S. The G+C content of the DNA is 34.4 mol %. The analysis of the 16S rRNA sequence revealed that strain Z-7986 belongs to the order Haloanaerobiales and represents a new genus in the family Halobacteroidaceae. We suggest the name Halonatronum saccharophilum gen. nov. sp. nov. The type strain of this species is Z-7986^T (= DSM13868, = Uniqem*211).     

Optimization of some parameters influencingThermoascus aurantiacus growth: Effects of lignin-related compounds

Statistical designs were used to optimize some parameters affecting the growth rate of a Brazilian strain ofThermoascus aurantiacus. The mycelial growth rate was measured using the horizontal tube method. Temperature of incubation and initial pH were the major factors affecting the growth rate. They were optimal at 6.0 and 48°C, respectively. The maximum growth rate was obtained in solid Czapek modified medium containing 1.5% glucose and 38.4 mEq L^–1NaNO₃. Under these conditions, the growth rate ofT. aurantiacus was 5.16±0.10 mm h^–1. Lignin-related compounds such as tannins and extractive substances added at 0.1% (w/v) to the minimal Czapek medium increased growth rate 14% and 29%, respectively.     

An optimum environment for the culturing of cytospora isolates from stone fruits. I. Temperature

Summary Four isolates ofCytospora cincta Fr. and 2 ofC. leucostoma Fr. were obtained from diseased Italian prune, President plum and Bing cherry trees.The minimum temperature for growth of these fungi was found to be 3° C. Temperatures of 45 °C. were lethal to all cultures. The optimum temperature for theC. cincta isolates on solid and liquid media was found to be 30° C.; for theC. leucostoma isolates, nearly 25° C. OneC. cincta isolate produced greatest radial growth on the solid medium at 35° C., but in the liquid medium produced maximum mycelium at 30° C.All factors considered, the conclusion was reached that the best single temperature for laboratory culture of the fungi was 30° C.Approved by the Director of the Idaho Agricultural Experiment Station as Research Paper No. 493.