Effect of temperature and humidity on development, survival and oviposition in laboratory populations of Eriworm, Philosamia ricini (Boisduval) (Lepidoptera Saturniidae)

Experiments were conducted on laboratory populations of Eriworm, Philosamia ricini Boisduval to study the effect of temperature and humidity on development, growth, survival and oviposition. Experiments were performed at four different temperatures (22 +/- 2 degrees C, 26 +/- 2 degrees C, 28 +/- 2 degrees C and 34 +/- 1 degrees C) each with three different humidities (50%, 70% and 90% relative humidity). Shortest developmental period (42 days) was observed in 28 +/- 2 degrees C and 70% RH. Longest developmental period was (63.6 days) observed in 22 +/- 2 degrees C at 50% RH. Highest larval weight (9.1 g) was found in 28 +/- 2 degrees C at 70% RH. Best pupal weight was observed in 26 +/- 2 degrees C at 70% RH. Weight of silk material was found to be maximum in 26 +/- 2 degrees C at 70% RH. Survival was best in 28 +/- 2 degrees C and 26 +/- 2 degrees C at 70% RH. Oviposition was found to be highest in 28 +/- 2 degrees C at 70% RH.     

Suppression of heat-induced HSP-70 by simultaneous exposure to 50 mT magnetic field

Effect of extremely low frequency magnetic field (ELFMF) at 50 mT and 60 Hz on heat-induced expression of heat shock protein 70 (hsp-70) was examined in HL60RG cells. No increase in hsp-70 production was observed in the cells after exposure to 50 mT ELFMF alone. Simultaneous exposure to 50 mT ELFMF in combination with mild heat at 42 and 40 degrees C suppressed heat-induced hsp-70 expression. The suppression of hsp-70 occurred when cells were simultaneously exposed to both for longer periods of more than 5 h. However, the suppression of hsp-70 was not observed at a magnetic density of 5 and 0.5 mT. This result suggests that exposure to 50 mT ELFMF may act on a protection against the concomitant mild heat stress in HL60RG cells.     

Acetate Degradation at 70 degrees C in Upflow Anaerobic Sludge Blanket Reactors and Temperature Response of Granules Grown at 70 degrees C

Anaerobic acetate degradation at 70 degrees C and at 55 degrees C (as a reference) was studied by running laboratory upflow anaerobic sludge blanket (UASB) reactors inoculated with mesophilic granular sludge. In UASB reactors fed with acetate-containing media (3 g of chemical oxygen demand [COD] per liter, corresponding to 47 mM acetate) approximately 50 days was needed at 70 degrees C and less than 15 days was needed at 55 degrees C to achieve an effluent COD of 500 to 700 mg/liter. In the UASB reactors at both 70 and 55 degrees C up to 90% of the COD was removed. Batch assays showed that sludges from two 70 degrees C UASB reactors, one run at a low effluent acetate concentration and the other run at a high effluent acetate concentration, exhibited slightly different responses to temperatures in the range from 37 to 70 degrees C. Both 70 degrees C sludges, as well as the 55 degrees C sludge, produced methane at temperatures of 37 to 73 degrees C. The 55 degrees C sludge exhibited shorter lag phases than the 70 degrees C sludges and higher specific methane production rates between 37 and 65 degrees C.     

Effect of Temperature on Composting of Sewage Sludge

The effect of temperature on the composting reaction of sewage sludge was investigated at 50, 60, and 70°C. The total amount of CO₂ evolved and the final conversion of volatile matter were maximum at 60°C., suggesting that the optimal temperature for composting was around 60°C. The specific CO₂ evolution rate (moles of CO₂ evolved per hour per viable cell) was maximum at 70°C. The isolated thermophilic bacterium which was dominant at 60°C but did not grow at 70°C showed that the rate of O₂ consumption measured on the agar plate at 70°C was four times higher than that at 60°C. This showed that the energy yielded from catabolism is rather uncoupled with the anabolism at 70°C in the metabolism of microorganisms indigenous in the compost. A higher respiratory quotient was observed at 70°C than at any other temperature.     

Uracil-DNA glycosylase of thermophilic Thermothrix thiopara.

An activity which released free uracil from dUMP-containing DNA was purified approximately 1,700-fold from extracts of Thermothrix thiopara, the first such activity to be isolated from extremely thermophilic bacteria. The enzyme appeared homogeneous, according to the results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It had a native molecular weight of 26,000 and existed as a monomer protein in water solution. The enzyme had an optimal activity at 70 degrees C, between pH 7.5 and 9.0, and in the presence of 0.2% Triton X-100. It had no cofactor requirement and was not inhibited by EDTA, but it was sensitive to N-ethylmaleimide. The purified enzyme did not contain any nuclease that acted on native or depurinated DNA. The Arrhenius activation energy was 76 kJ/mol between 30 and 50 degrees C and 11 kJ/mol between 50 and 70 degrees C. The rate of heat inactivation of the enzyme followed first-order kinetics with a half-life of 2 min at 70 degrees C. Ammonium sulfate and bovine serum albumin protected the enzyme from heat inactivation. One T. thiopara cell contains enough activity to release about 2 X 10(8) uracil residues from DNA during one generation time at 70 degrees C.     

Effect of Temperature on the Fatty Acid Composition of Thermus aquaticus

Thermus aquaticus contains four major fatty acids, iso-C(15) (28%), iso-C(16) (9%), normal-C(16) (13%), and iso-C(17) (48%), when grown at 70 C, as determined by gas chromatography and mass spectrometry. Small amounts of iso-C(12), normal-C(12:1), iso-C(13), normal-C(14), iso-C(14), and normal-C(15:1) were also detected. A change in growth temperature (50 to 75 C at 5-C intervals) affects a shift in the proportions of some of the fatty acids. The proportions of the monoenoic and branched-C(17) fatty acids decreased and the proportions of the higher-melting iso-C(16) and normal-C(16) fatty acids increased. Cells grown at 75 C contained 70% more total fatty acids than cells grown at 50 C. The largest increases, in absolute amounts, were in the content of iso-C(16) and normal-C(16) fatty acids, with only a 1.6-fold increase in the major iso-C(15) and iso-C(17) fatty acids. There was a 2.5-fold decrease in normal-C(15:1) and at least a 24-fold decrease in anteiso-C(17), which is present at 50 and 55 C but not at higher temperatures. There was no difference in proportion or amount of fatty acids between exponential and stationary-phase cells grown at 70 C. When cells were grown on glutamate instead of yeast-extract and tryptone at 70 C, the total fatty acid content remained constant, but there was an increase in the proportions of iso-C(16) and normal-C(16) fatty acids concomitant with a decrease in the proportions of the iso-C(15) and iso-C(17) fatty acids.     

Effects of temperature and relative humidity on biological indicators used for ethylene oxide sterilization.

A study was made to determine the effects of temperature and moisture on the D-value of a common biological indicator. Relative humidity (RH) was varied between 10 and 70% in increments of 10%, and temperature was varied between 30 and 70 degrees C in increments of 10 degrees C. Temperature was found to have a pronounced effect on the D-value. At 60% RH, the D-value varied from 15.0 min at 30 degrees C to 1.1 min at 70 degrees C. When RH was plotted against the average D-value at the various temperatures, the temperature curves at or above 50 degrees C were more erratic and the RH had a significant effect. The study showed that temperature and RH must be controlled if biological indicators are to be properly calibrated for use in ethylene oxide sterilization.     

ATP-independent thermoprotective activity of Nicotiana tabacum heat shock protein 70 in Escherichia coli

To study the functioning of HSP70 in Escherichia coli, we selected NtHSP70-2 (AY372070) from among three genomic clones isolated in Nicotiana tabacum. Recombinant NtHSP70-2, containing a hexahistidine tag at the amino-terminus, was constructed, expressed in E. coli, and purified by Ni(2+) affinity chromatography and Q Sepharose Fast Flow anion exchange chromatography. The expressed fusion protein, H(6)NtHSP70-2 (hexahistidine-tagged Nicotiana tabacum heat shock protein 70-2), maintained the stability of E. coli proteins up to 90 degrees C. Measuring the light scattering of luciferase (luc) revealed that NtHSP70-2 prevents the aggregation of luc without ATP during high-temperature stress. In a functional bioassay (1 h at 50 degrees C) for recombinant H(6)NtHSP70-2, E. coli cells overexpressing H(6)NtHSP70-2 survived about seven times longer than those lacking H(6)NtHSP70-2. After 2 h at 50 degrees C, only the E. coli overexpressing H(6)NtHSP70-2 survived under such conditions. Our NtHSP70-2 bioassays, as well as in vitro studies, strongly suggest that HSP70 confers thermo-tolerance to E. coli.     

Lethal effects of high temperatures on nondiapausing pupae ofBathyplectes curculionis [Hym.: Ichneumonidae]

Nondiapausing pupae ofBathyplectes curculionis (Thomson) were studied under laboratory conditions. The mortality caused by 8 temperatures between 25–48°C at 20% and 70% relative humidity was measured at 10 exposure times between 15 min-24 h. There was no significant mortality at 25°C. Between 30 and 40°C, mortality occurred from long exposures only, with lethal effects becoming greater at each increase in temperature. At 43°C mortality occurred from relatively short exposures, with 100% at 4 h. Exposure times for 50% mortality averaged 16.58 h at 38°C, 1.08 h at 43°C and 0.31 h at 48°C. A slightly higher mortality occurred at 20% relative humidity than at 70% at temperatures between 35 and 40°C. At temperatures above 43°C no effects of relative humidity were noted. Afternoon soil surface temperatures in recently cut alfalfa fields commonly exceeded 50°C during July in northern Utah.     

Thermostability of bacteriophage T4 fibritin and its deletion mutants]

The thermal stability of a series of recently obtained mutants of fibritin from bacteriophage T4 (a superhelical fibrous homotrimer with parallel-packed subunits each containing 486 amino acid residues) progressively truncated from the subunit N-end was studied during incubation at 40-90 degrees C in the presence of a surfactant (2% SDS). The mutant fibritins, G, B, C, and E, contained 443, 276, 231, and 120 amino acid residues, respectively. One more truncated mutant (fibritin S1, 108 amino acid residues) was obtained. The 2% SDS-PAGE showed that the migration mobilities of all these proteins corresponded to apparent molecular masses substantially greater than those of the preliminarily heated samples (3 min at 100 degrees C). The heating of the intact fibritin and the mutant G at 50-70 degrees C for 10 min resulted in the formation of a form with an apparent molecular mass higher than 200 kDa. This form probably represented a trimeric protein with a partly denatured N-terminal part. Fibritins B and C were more stable and were only partly denatured into monomers even at 70-90 degrees C. The short mutants E and S1 dissociated into monomers at temperatures from 45 to 50 degrees C. The denaturation of mutants B, C, E, and S1 proceeded in one stage without formation of any intermediate form. The stability of the trimeric molecules of native fibritin under PAGE denaturing conditions and the behavior of the intact protein during heating in the temperature range of 50-70 degrees C might be used for the identification of fibritin intermediate forms upon folding in vivo. The refolding capability was found for fibritin and its mutants denatured by heating at low temperatures in the presence of 2% SDS.     

Assessment of ram sperm membrane integrity following different thawing procedures

Semen from five 2.5-yr-old rams selected for use in an AI program was collected over 3 consecutive days using an artificial vagina. The semen was diluted with a skim milk extender containing 7% glycerol (v/v), packed in French mini-straws (approx. 100 mill/straw), and frozen in a programmable freezer. Three freezing operations were carried out per ram. Three straws per freezing operation were subjected to the following thawing procedures: 1) 70 degrees C, 5 sec; 2) 50 degrees C, 9 sec and 3) 35 degrees C, 12 sec. Post-thaw sperm motility was subjectively assessed using a phase contrast microscope; while the combined fluorochromes carboxyfluorescein diacetate and propidium iodide (CFDA/PI), the hypo-osmotic swelling test (HOS) and the presence of normal apical ridges (NAR's) were used to determine the degree of sperm membrane integrity. Significant differences between thawing treatments were found for post-thaw motility (P < .05) and membrane integrity (P < 0.01), and variation among rams was statistically significant. Post-thaw sperm motility as well as the percentage of spermatozoa showing intact membranes were significantly higher (P < 0.01) for straws thawed at 70 degrees C than for those thawed at 35 degrees C (67.0 +/- 1.1 and 63.0 +/- 1.1%, and 50.5 +/- 1.5 and 41.7 +/- 1.5%, respectively). However, no corresponding statistically significant difference could be found for these parameters when 70 degrees C and 50 degrees C thawing were compared. It was concluded that sperm can be thawed at 50 degrees C for 9 sec instead of 70 degrees C for 5 sec without further reducing sperm motility or membrane integrity. This lower thawing temperature would facilitate the widespread use of frozen/thawed ram semen under farm conditions in Sweden.     

Fertility results after different thawing procedures for ram semen frozen in minitubes and mini straws

The effect of different thawing procedures for ram semen frozen in minitubes and mini straws on the fertility of sheep was tested in a field trial in which 727 Norwegian crossbred ewes, aged between six months and five-and-a-half years from nine farms, were inseminated with frozen-thawed semen in natural estrous. Minitubes were thawed at 70 degrees C for 8 s (T70) and mini straws either at 70 degrees C for 5 s (S70), 50 degrees C for 9 s (S50), or 35 degrees C for 12 s (S35). Cervical insemination with 200 x 10(6) spermatozoa resulted in 25-day non-return rates of 78.7, 69.0, 73.6, and 72.9% (overall 73.6%), respectively, and lambing rates of 77.6, 66.1, 71.4, and 68.9% (overall 71.0%), respectively. There was a significantly higher lambing rate for T70 compared to S35 (P=0.03) and S70 (P=0.02), respectively, but not compared to S50 (P=0.29). Age of the ewes (P=0.02), farmers (P=0.02) and the interaction between farmer x straw type/thawing temperature (P=0.01) had a significant effect on the lambing rate. In conclusion, the superior fertility results achieved for minitubes compared to mini straws have to be carefully evaluated in relation to the possible application of a more rational semen production and simplified semen handling at AI, when using mini straws thawed at 35 degrees C.     

Acetate Degradation at 70°C in Upflow Anaerobic Sludge Blanket Reactors and Temperature Response of Granules Grown at 70°C

Anaerobic acetate degradation at 70°C and at 55°C (as a reference) was studied by running laboratory upflow anaerobic sludge blanket (UASB) reactors inoculated with mesophilic granular sludge. In UASB reactors fed with acetate-containing media (3 g of chemical oxygen demand [COD] per liter, corresponding to 47 mM acetate) approximately 50 days was needed at 70°C and less than 15 days was needed at 55°C to achieve an effluent COD of 500 to 700 mg/liter. In the UASB reactors at both 70 and 55°C up to 90% of the COD was removed. Batch assays showed that sludges from two 70°C UASB reactors, one run at a low effluent acetate concentration and the other run at a high effluent acetate concentration, exhibited slightly different responses to temperatures in the range from 37 to 70°C. Both 70°C sludges, as well as the 55°C sludge, produced methane at temperatures of 37 to 73°C. The 55°C sludge exhibited shorter lag phases than the 70°C sludges and higher specific methane production rates between 37 and 65°C.     

Laundry detergent compatibility of the alkaline protease from Bacillus cereus

The endogenous protease activity in various commercially available laundry detergents of international companies was studied. The maximum protease activity was found at 50 degrees C in pH range 10.5-11.0 in all the tested laundry detergents. The endogenous protease activity in the tested detergents retained up to 70% on incubation at 40 degrees C for 1 h, whereas less than 30% activity was only found on incubation at 50 degrees C for 1 h. The alkaline protease from an alkalophilic strain of Bacillus cereus was studied for its compatibility in commercial detergents. The cell free fermented broth from shake flask culture of the organism showed maximum activity at pH 10.5 and 50 degrees C. The protease from B. cereus showed much higher residual activity (more than 80%) on incubation with laundry detergents at 50 degrees C for 1 h or longer. The protease enzyme from B. cereus was found to be superior over the endogenous proteases present in the tested commercial laundry detergents in comparison to the enzyme stability during the washing at higher temperature, e.g., 40-50 degrees C.     

Thermal inactivation of foot-and-mouth disease viruses in suspension

The heat resistance of foot-and-mouth disease virus (FMDV) strains isolated from outbreaks in Thailand was investigated in phosphate-buffered saline (PBS) at 50, 60, 70, 80, 90, and 100 degrees C. The first-order kinetic model fitted most of the observed linear inactivation curves. The ranges of decimal-reduction time (D value) of FMDV strains at 50, 60, 70, 80, 90, and 100 degrees C were 732 to 1,275 s, 16.37 to 42.00 s, 6.06 to 10.87 s, 2.84 to 5.99 s, 1.65 to 3.18 s, and 1.90 to 2.94 s, respectively. The heat resistances of FMDV strains at lower temperature (50 degrees C) were not serotype specific. The effective inactivating temperature is approximately 60 degrees C. Heat resistances of FMDV strains at 90 and 100 degrees C were not statistically different (P > 0.05), while the FMDV serotype O (OPN) appeared to be the most heat resistant at 60 to 80 degrees C. The other observed inactivation curves were linear with shoulder or tailing (biphasic curves). The shoulder effect was mostly observed at 90 and 100 degrees C, while the tailing effect was mostly observed at 50 to 80 degrees C. The adjusted D values in the case of shoulder and tailing effects did not affect the overall estimated heat resistance of these FMDV strains, so even unadjusted D values of deviant inactivation curves were legitimate. The z values of FMDV serotypes O, A, and Asia 1 were 21.78 to 23.26, 20.75 to 22.79, and 19.87 degrees C, respectively. The z values of FMDV strains studied were not statistically significantly different (P > 0.05). The results of this study indicated that the heat resistance in PBS of FMDV strains from Thailand was much less than had been reported for foreign epidemic FMDV strains.     

Role of polyamines in the binding of initiator tRNA to the 70S ribosomes of extreme thermophilic bacterium Calderobacterium hydrogenophilum

Slowly cooled cells of an extreme thermophilic eubacterium Calderobacterium hydrogenophilum possess ribosomes with weakly associated subunits. These ribosomal subunits are capable of association to 70S ribosomes either at higher Mg²⁺ concentrations (30–40 mM) or at 4–10 mM Mg²⁺ and in the presence of polyamines. The contribution of 30S and 50S subunits to the hydrodynamic stability of ribosomes was examined by forming hybrid 30S–50S couples from C. hydrogenophilum and Escherichia coli. At lower Mg²⁺ (4–10 mM) heterogeneous subunits containing 30S E. coli and 50S C. hydrogenophilum and homogeneous subunits of the thermophilic bacterium associated only in the presence of polyamines. Ribosomal subunits associated at 30 mM Mg²⁺ lose thermal stability and activity concerning poly(AUG)-dependent binding of f[³H]Met-tRNA to the P-site on 70S ribosomes or translation of poly(UG). Poly(AUG), deacylated-tRNA or initiator-tRNA have no valuable effect on association of 30S and 50S subunits. Protein synthesis initiation factor IF3 of C. hydrogenophilum prevents association of ribosomal subunits to 70S ribosomes at physiological temperature (70°C). The factor also stimulates dissociation of 70S ribosomes of E. coli at 37°C. The codon-specific binding of f[³H]Met-tRNA to homogeneous 70S ribosomes of C. hydrogenophilum at 70°C is dependent on the presence of initiation factors and concentrations of tri-pentaamines. However, excess of polyamines inhibited the reaction. Our results indicate that tri-pentaamines enhance conformational stability of 70S initiation complex at elevated temperatures.     

Characterization of a thermostable Bacillus stearothermophilus alpha-amylase

Liquefying-type Bacillus stearothermophilus alpha-amylase was characterized. The coding gene was cloned in Bacillus subtilis and the enzyme was produced in three different host organisms: B. stearothermophilus, B. subtilis, and Escherichia coli. Properties of the purified enzyme were similar irrespective of the host. Temperature optimum was at 70-80 degrees C and pH optimum at 5.0-6.0. The enzyme was stable for 1 h in the pH range 6.0-7.5 at 80 degrees C. The enzyme was stabilized by Ca2+, Na+, and bovine serum albumin. About 50% of the activity remained after heating at 70 degrees C for 5 days or 45 min at 90 degrees C. Metal ions Cd2+, Cu2+, Hg2+, Pb2+, and Zn2+ were inhibitory, whereas EDTA, ethylene glycol bis(beta-aminoethyl ether) N,N,N',N'-tetraacetic acid, and Tendamistat were without effect. The enzyme was fully active after treatment in acetone or ethanol at 55 or 70 degrees C, respectively, for 30 min. Sodium dodecyl sulfate (1%) did not affect stability, whereas 6 M urea denatured totally at 70 degrees C. The Km value for soluble starch was 14 mg/ml. Mr is 59,000 and pI 8.8. The only difference between the enzymes produced in different hosts was in signal peptide processing.     

Purification and characterization of thermostable pectate lyase with protopectinase activity from thermophilic Bacillus sp. TS 47

A strain of thermophilic bacterium, Bacillus sp., with pectolytic activity has been isolated. It produced an extracellular endo-polygalacturonate trans-eliminase (PL, EC 4.2.2.1) when grown at 60 degrees C on a medium containing polygalacturonate (PGA). The PL was purified by hydrophobic, cation exchange, and size exclusion column chromatographies. The molecular mass of the enzyme was 50 kDa by SDS-PAGE. The isoelectric point of the enzyme was pH 5.3. The enzyme had a half-life of 13 and 1 h at 65 and 70 degrees C, respectively, and showed optimal activity around at 70 degrees C and pH 8.0. It had protopectinase activity, besides PL activity, on lemon protopectin and cotton fibers. The first 20 amino acids sequence of the enzyme had significant similarity with that of PL from methophilic Bacillus subtilis, with 50% identity.     

Destructive effect of heating against toxoplasma oocysts.

Heating was examined for destructive effect against Toxoplasma oocysts, both unsporulated and sporulated, of the O-1 and O-3 strains. Sporulation-inhibition rates were measured by counting sporulated and unsporulated oocysts in each examination. As a result, the sporulation of Toxoplasma oocysts was completely inhibited by exposure to 60 or 70 degrees C for 10 seconds, 55 degrees C for 30 seconds, 50 degrees C for 2.5 minutes. 45 degrees C for 1 hour, or 37 degrees C for 48 hours. When examined by the mouse inoculation method, the infectivity of sporulated oocysts became extinct after heating at 90 degrees C for 30 seconds, 80 degrees C for 1 minute, 70 degrees C for 2 minutes, 55 or 60 degrees C for 15 minutes, or 50 degrees C for 30 minutes. It was confirmed that heating was effective for the sterilization of Toxoplasma oocysts.     

Heat-shock responses in two leguminous plants: a comparative study

Relative growth rates, basal and acclimated thermotolerance, membrane damage, fluorescence emission, and relative levels of free and conjugated ubiquitin and HSP70 were compared after 2 h of treatment at different temperatures between Prosopis chilensis and Glycine max (soybean), cv. McCall, to evaluate if the thermotolerance of these two plants was related to levels of accumulation of heat shock proteins. Seedlings of P. chilensis germinated at 25 degrees C and at 35 degrees C and grown at temperatures above germination temperature showed higher relative growth than soybean seedlings treated under the same conditions. The lethal temperature of both species was 50 degrees C after germination at 25 degrees C. However, they were able to grow at 50 degrees C after germination at 35 degrees C. Membrane damage determinations in leaves showed that P. chilensis has an LT(50) 6 degrees C higher than that of soybean. There were no differences in the quantum yield of photosynthesis (F(v)/F(m)), between both plants when the temperatures were raised. P. chilensis showed higher relative levels of free ubiquitin, conjugated ubiquitin and HSP70 than soybean seedlings when the temperatures were raised. Time-course studies of accumulation of these proteins performed at 40 degrees C showed that the relative accumulation rates of ubiquitin, conjugated ubiquitin and HSP70 were higher in P. chilensis than in soybean. In both plants, free ubiquitin decreased during the first 5 min and increased after 30 min of heat shock, conjugated ubiquitin increased after 30 min and HSP70 began to increase dramatically after 20 min of heat shock. From these data it is concluded that P. chilensis is more tolerant to acute heat stress than soybean.