Temperature requirements ofScytosiphon lomentaria (Scytosiphonales,Phaeophyta) from the Gulf of Thessaloniki,Greece, in relation to geographic distribution

Temperature requirements for growth, reproduction and formation of macrothalli of a day-neutral strain ofScytosiphon lomentaria from the Gulf of Thessaloniki were experimentally determined and correlated with the geographic distribution in the North Atlantic Ocean. The microthallus grew in a wider temperature interval and better at higher temperatures than did the macrothallus. Germlings acclimated to 5 or 15°C grew sufficiently (>20% of maximum rate) and developed into macrothalli at 5–25°C and 5–27°C. Macrothalli acclimated to 10 or 15°C grew sufficiently at 5–20°C. Macrothalli acclimated to 15°C survived at −1°C and reproduced at 5 to 23°C. Regardless of the acclimation temperature, germlings and macrothalli grew optimally (>80% of maximum rate) at 15–25°C and at 10–15°C. The experimental data explain only the southern distribution boundary ofScytosiphon in the North Atlantic. This boundary is composite in nature: on the European coasts it is a growth boundary, whereas on the American coasts it is a lethal one.     

Reproduction,adult survival and intrinsic rate of growth ofUrolepis rufipes [Hymenoptera: Pteromalidae], a pupal parasitoid of house flies,Musca domestica

Urolepis rufipes Ashmead, a recently discovered parasitoid of house flies at New York dairies, was reared at 15, 20, 25, 30 and 34°C to measure daily fertility, fecundity and adult survivorship. Little reproduction occurred at 15°C, and only a few ♀ successfully emerged at 34°C. The intrinsic rate of growth was fastest at 30°C (0.282 ♀/day), but fecundity was highest at 25°C (165.5 hosts attacked, producing 124.5 progeny). Some reproductive statistics at 25°C were: net reproductive rate (R₀=72.1 ♀/♀, generation time =18.7 days, intrinsic rate of increase (r_m)=0.228, finite rate of increase (λ)=1.26, daily birth rate =0.302, daily death rate =0.021 and Fisher's reproductive value =418. Sex ratio (average =75.9%) did not vary significantly with temperature (between 20–30°C) nor with mother's age.      

An energy budget for Simocephalus vetulus (O. F. Muller) (Crustacea : Cladocera)

We discuss the energetics of a cladoceran, Simocephalus vetulus at different temperatures (8.0 ± 1.0, 15.0 ± 1.0, 21.0 ± 1.0 and 28.0 ± 1.0 °C) and food (Chlamydomonas sp.) concentrations (25 × 10³, 50 × 10³, 75 × 10³ and 100 × 10³ cells ml⁻¹). Increase in temperature accelerated ingestion and, to some extent, oxygen consumption. The study revealed a high reproduction efficiency in S. vetulus. Net growth efficiency (ECI) was higher (13.17–41.18%) in pre-adults than in adults (2.71–8.40%). The assimilated energy (A) increased with increasing food concentration at all temperatures. Assimilation efficiency (AD) decreased with increasing food concentrations. The energy used for growth (P) was nearly constant at all food levels because the egested energy increased and assimilation efficiency decreased as food concentration increased.     

Effects of temperature on growth and efficiency of food utilization in fifth-instar caterpillars of the tobacco hornworm, Manduca sexta

Fifth-instar larvae of Manduca sexta were reared from hatching on artificial diet at 15, 20, 25, 30 and 35°C. Total development time decreased with increasing temperature. Very few larvae (12%) survived at 15°C, so this temperature was not considered further. There was some mortality at 30°C (11%), and at 35°C (50%).The absolute rate of growth in the fifth instar was faster at 25 than at 20°C, but was similar at 25, 30 and 35°C. This was true both for caterpillars that were chronically exposed to experimental temperatures (i.e. since hatching) and for those acutely exposed (i.e. reared up to fifth instar at 25°C).There was a progressive decrease with higher rearing temperatures in both the initial and final sizes of chronically exposed fifth-instar larvae. Acutely exposed caterpillars matched for initial size showed smaller temperature related differences in final size. Because of these size differences there were differences in relative growth rate which did not reflect true differences in absolute growth rate.Total food consumed by chronically exposed caterpillars was greatest at the lowest temperature (20°C), and decreased progressively with increasing temperature. The absolute rate of food consumption increased from 20 to 25°C, but did not vary significantly between 25 and 35°C. Differences in the sizes of the insects at the different temperatures meant that there were differences among relative measures of consumption that did not reflect absolute food consumption.For chronically exposed caterpillars, none of the three usual indices of food conversion efficiency (AD, ECI and ECD) varied significantly with temperature between 20 and 35°C. This implies that the effects of temperature on metabolic costs are closely matched to food consumption.Oxygen consumption increased with temperature between 20 and 25°C but was temperature compensated between 25 and 35°C.These findings are discussed in terms of their implications for the optimal temperature for growth in Manduca.     

Influences of Culture Temperature on the Growth, Lipid Content and Fatty Acid Composition of Aurantiochytrium sp. Strain mh0186

The growth, lipid content, and fatty acid composition of Aurantiochytrium sp. strain mh0186 at different temperatures were investigated. Strain mh0186 grew well at 15–30°C, but weakly at 10°C. The biomass at 15–30°C was significantly higher than at 10 and 35°C, and the total lipid at 15–35°C was significantly higher than that at 10°C. The amount of DHA in the total fatty acid was highest at 10°C and decreased in response to temperature increase. The content of DHA (mg/g-dry cell weight) at 15–30°C were significantly higher than those at 35°C and those at 15–25°C were significantly higher than those at 10 and 35°C. The DHA yield at 15–35°C was significantly higher than those at 10 and 35°C. Unsaturation of fatty acid was regulated by temperature and was enhanced in response to temperature decrease. The ratio of DHA to DPA varied at different temperatures.     

The Influence of Water Activity and Temperature on Germination,Growth and Sporulation of <Emphasis Type="Italic">Stachybotrys chartarum</Emphasis> Strains

The objectives were to determine the influence of water activity (a_w, 0.997–0.92) and temperature (10–37°C) and their interactions on conidial germination, mycelial growth and sporulation of two strains of Stachybotrys chartarum in vitro on a potato dextrose medium. Studies were carried out by modifying the medium with glycerol and either spread plating with conidia to evaluate germination and germ tube extension or centrally inoculating treatment media for measuring mycelial growth rates and harvesting whole colonies for determining sporulation. Overall, germination of conidia was significantly influenced by a_w and temperature and was fastest at 0.997–0.98 a_w between 15 and 30°C with complete germination within 24 h. Germ tube extension was found to be most rapid at similar a_w levels and 25–30°C. Mycelial growth rates of both strains were optimal at 0.997 a_w between 25 and 30°C, with very little growth at 37°C. Sporulation was optimum at 30°C at 0.997 a_w. However, under drier conditions, this was optimum at 25°C. This shows that there are differences in the ranges of a_w x temperature for germination and growth and for sporulation. This may help in understanding the role of this fungal species in damp buildings and conditions under which immune-compromised patients may be at risk when exposed to such contaminants in the indoor air environment.     

Effects of elevated temperature on bacterial community structure and function in bioreactors treating a synthetic wastewater

The impact of elevated temperature on bacterial community structure and function during aerobic biological wastewater treatment was investigated. Continuous cultures, fed a complex growth medium containing gelatin and α-lactose as the principal carbon and energy sources, supported mixed bacterial consortia at temperatures ranging from 25–65°C. These temperature- and substrate-acclimated organisms were then used as inocula for batch growth experiments in which the kinetics of microbial growth and substrate utilization, efficiency of substrate removal, and mechanism of substrate removal were compared as functions of temperature. Bacterial community analysis by denaturing gradient gel electrophoresis (DGGE) revealed that distinct bacterial consortia were supported at each temperature. The efficiency of substrate removal declined at elevated temperatures. Maximum specific growth rates and the growth yield increased with temperature from 25–45°C, but then decreased with further elevations in temperature. Thus, maximum specific substrate utilization rates did not vary significantly over the 40°C temperature range (0.64 ± 0.04 mg COD mg⁻¹ dry cell mass h⁻¹). A comparison of the degradation of the protein and carbohydrate portions of the feed medium revealed a lag in α-lactose uptake at 55°C, whereas both components were utilized simultaneously at 25°C. Journal of Industrial Microbiology & Biotechnology (2000) 24, 140–145. Received 09 August 1999/ Accepted in revised form 12 November 1999     

Influence of complex nutrients, temperature and pH on bacteriocin production by Lactobacillus sakei CCUG 42687

The effects of process conditions and growth kinetics on the production of the bacteriocin sakacin P by Lactobacillus sakei CCUG 42687 have been studied in pH-controlled fermentations. The fermentations could be divided into phases based on the growth kinetics, phase one being a short period of exponential growth, and three subsequent ones being phases of with decreasing specific growth rate. Sakacin P production was maximal at 20 °C. At higher temperatures (25–30 °C) the production ceased at lower cell masses, when less glucose was consumed, resulting in much lower sakacin P concentrations. With similar media and pH, the maximum sakacin P concentration at 20 °C was seven times higher than that at 30 °C. The growth rate increased with increasing concentrations of yeast extract, and the maximum concentration and specific production rate of sakacin P increased concomitantly. Increasing tryptone concentrations also had a positive influence upon sakacin P production, though the effect was significantly lower than that of yeast extract. The maximum sakacin P concentration obtained in this study was 20.5 mg l⁻¹. On the basis of the growth and production kinetics, possible metabolic regulation of bacteriocin synthesis is discussed, e.g. the effects of availability of essential amino acids, other nutrients, and energy. Received: 7 June 1999 / Received revision: 15 September 1999 / Accepted: 17 September 1999     

Effects of constant and fluctuating soil temperature on growth,development and nutrient uptake of maize seedlings

Summary The effect of constant and fluctuating soil temperature and two soil moisture regimes on the growth, development, transpiration and nutrient uptake by maize seedlings was studied in a greenhouse investigation. The constant root temperatures were maintained at 30, 34, 35, 36, 37, and 38°C for both 250 and 750 cm of soil moisture suctions. The fluctuating root temperature, for 250 cm of soil moisture suction only, of 30–35, 30–39, 30–40, 30–45 and 30–48°C were maintained to simulate the soil temperature regime under field conditions. The constant root temperature of 35°C and fluctuating temperature between 30–40°C significantly decreased the shoot and root growth and transpiration rate. On the average, there was 1.3 and 0.7 g decrease in fresh shoot weight and 0.36 and 0.30 g in fresh root weight per degree increase in root temperature for 250 and 750 soil moisture suction, respectively. In general, the effect of high soil moisture suction on maize seedlings was more severe when at high root temperature. The shoot and root concentration of N, P, and K decreased while that of B increased with increase in root temperature. The root concentration of Zn also decreased with increase in root temperature.     

Torpor patterns,arousal rates,and temporal organization of torpor entry in wildtype and UCP1-ablated mice

In eutherian mammals, uncoupling protein 1 (UCP1) mediated non-shivering thermogenesis from brown adipose tissue (BAT) provides a mechanism through which arousal from torpor and hibernation is facilitated. In order to directly assess the magnitude by which the presence or absence of UCP1 affects torpor patterns, rewarming and arousal rates within one species we compared fasting induced torpor in wildtype (UCP1^+/+) and UCP1-ablated mice (UCP^−/−). Torpor was induced by depriving mice of food for up to 48 h and by a reduction of ambient temperature (T _a) from 30 to 18°C at four different time points after 18, 24, 30 and 36 h of food deprivation. In most cases, torpor bouts occurred within 20 min after the switch in ambient temperature (30–18°C). Torpor bouts expressed during the light phase lasted 3–6 h while significantly longer bouts (up to 16 h) were observed when mice entered torpor during the dark phase. The degree of hypometabolism (5–22 ml h⁻¹) and hypothermia (19.5–26.7°C) was comparable in wildtype and UCP1-ablated mice, and both genotypes were able to regain normothermia. In contrast to wildtype mice, UCP1-ablated mice did not display multiple torpor bouts per day and their peak rewarming rates from torpor were reduced by 50% (UCP1^+/+: 0.24 ± 0.08°C min⁻¹; UCP1^−/−: 0.12 ± 0.04°C min⁻¹). UCP1-ablated mice therefore took significantly longer to rewarm from 25 to 32°C (39 vs. 70 min) and required 60% more energy for this process. Our results demonstrate the energetic benefit of functional BAT for rapid arousal from torpor. They also suggest that torpor entry and maintenance may be dependent on endogenous rhythms.     

Effect of temperature on growth,proton extrusion and membrane potential in maize (<Emphasis Type="Italic">Zea mays</Emphasis> L.) coleoptile segments

The effects of temperature (5–45°C) on endogenous growth, growth in the presence of either indoleacetic acid (IAA) or fusicoccin (FC), and proton extrusion in maize coleoptile segments were studied. In addition, membrane potential changes at some temperatures were also determined. It was found that in this model system endogenous growth exhibits a clear maximum at 30°C, whereas growth in the presence of IAA and FC shows the maximum value in the range 30–35°C and 35–40°C, respectively. Simultaneous measurements of growth and external medium pH indicated that FC at stressful temperatures was not only much more active in the stimulation of growth, but was also more effective in acidifying the external medium than IAA. Also the addition of either IAA or FC to the bathing medium at 30 and 40°C did not change the kinetic characteristic of membrane potential changes observed for both substances at 25°C. However, the increased temperature significantly decreased IAA and FC-induced membrane hyperpolarization. IAA in the incubation medium, at 10°C, brought about additional membrane depolarization (apart from the one induced by low temperature). In contrast to IAA, FC at 10°C caused gradual repolarization of membrane potential, which correlated with both FC-induced growth and FC-induced proton extrusion. A plausible interpretation for temperature-induced changes in growth of maize coleoptile segments is that, at least in part, these changes were mediated via a PM H⁺-ATPase activity.     

Effects of extreme changes of sea water temperature and salinity on the development of the sand dollar <Emphasis Type="Italic">Scaphechinus mirabilis</Emphasis>

The combined effects of temperatures of 14, 17, 20, 22, and 25°C and salinities of 36–12‰ on embryos and larvae of the sand dollar Scaphechinus mirabilis was studied. Embryonic development is the most sensitive stage in the early ontogenesis of S. mirabilis. It is completed at a temperature of 14–20°C in a salinity range of 36–24‰ and at temperature of 22°C to 26‰. The fertilization proceeds in wider ranges of temperature and salinity. Among the swimming larvae, blastulae showed the greatest resistance to variations of these environmental factors. All the larvae survived at a temperature of 14–22°C and a salinity of 36–20‰, and more than 70% of them at 18‰. The pluteus I is the most vulnerable stage; probably this is related to the formation of the larval skeleton and transition to phytoplankton feeding. The survival of larvae at the age of 20 days was 100% at 14–22° C and a salinity of 36–24‰, most of them survived at 14–20°C and a salinity 18‰. The temperature 25 ° C is the most damaging for early development of S. mirabilis. The duration of development of that species lasts 28.5–29 days at 20°C and a salinity of 32.2–32.6‰. At 20 and 22°C, the larvae settled and completed metamorphosis more quickly if sand from the parental habitat was present. The larvae did not settle during the experiment (14 days) at 14 ° C and in the absence of sand.     

<Emphasis Type="Italic">Haliphthoros milfordensis</Emphasis> isolated from black tiger prawn larvae (<Emphasis Type="Italic">Penaeus monodon</Emphasis>) in Vietnam

 A marine fungus was isolated from the black tiger prawn Penaeus monodon at Nha Trang, Vietnam, on March 20, 2001 and named isolate NJM 0131. The fungus was identified as Haliphthoros milfordensis from the characteristics of asexual reproduction, and its physiological characteristics were investigated. Although the optimum temperature for growth of the isolate was 25°–30°C, the fungus grew at a wide range of temperatures (15°–40°C). H. milfordensis grew well in 50%–100% seawater, but poorly in PYG agar containing 1.0%–5.0% NaCl and KCl. The fungus grew at a wide range of pH (4.0–11.0) with the optimum pH value of 7.0–9.0. The isolate also showed pathogenicity to swimming crab larvae (Portunus trituberculatus) by artificial infection, but mortality was not high. This is the first report of disease in the black tiger prawn P. monodon in Vietnam caused by H. milfordensis. Received: July 22, 2002 / Accepted: January 21, 2003 Correspondence to:K. Hatai     

Morphological,cultural, and biodestructive peculiarities of <Emphasis Type="Italic">Chaetomium</Emphasis> species

Chaetomium is a fungus species that inhabits different cellulose substrates. Some species of this genus destroy books, textile, and wood. This genus is of particular interest due to its antagonistic and enzyme peculiarities. Studies on morphological and cultural features of Chaetomium species have both theoretical and practical output. Growth rates and development of C. globosum, C. funicola, C. elatum, and C. spirale were studied under different temperatures (17–20°C, 25°C, 27°C, 30°C, and 33–35°C) and carbon source media (glucose, saccharose, mannite, lactose, amylum, and cellulose). The optimal growth temperature was 25–27°C for all the studied species, while the temperature range of 33–35°C inhibited the colonies’ growth. Growth dynamics and colony shape and morphology, as well as development of overhead mycelium and ascocarps, varied greatly in different Chaetomium species in regard to the carbon source media. When comparing the destructive effect of four studied species and C. murorum on craft paper, the highest activity was registered for C. globosum, C. funicola, and C. elatum.     

Thermal ecotypes of amphi-Atlantic algae. I. Algae of Arctic to cold-temperate distribution (Chaetomorpha melagonium,Devaleraea ramentacea andPhycodrys rubens)

Three species of Arctic to cold-temperate amphi-Atlantic algae, all occurring also in the North Pacific, were tested for growth and/or survival at temperatures of −20 to 30°C. When isolates from both western and eastern Atlantic shores were tested side-by-side, it was found that thermal ecotypes may occur in such Arctic algae.Chaetomorpha melagonium was the most eurythermal of the 3 species. Isolates of this alga were alike in temperature tolerance and growth rate but Icelandic plants were more sensitive to the lethal temperature of 25°C than were more southerly isolates from both east and west. With regard toDevaleraea ramentacea, one Canadian isolate grew extraordinarily well at −2 and 0°C, and all tolerated temperatures 2–3°C higher than the lethal limit (18–20°C) of isolates from Europe. ConcerningPhycodrys rubens, both eastern and western isolates died at 20°C but European plants tolerated the lethal high temperature longer, were more sensitive to freezing, and attained more rapid growth at optimal temperatures. The intertidal species,C. melagonium andD. ramentacea, both survived freezing at −5 and −20°C, at least for short time periods.C. melagonium was more susceptible thanD. ramentacea to desiccation. Patterns of thermal tolerance may provide insight into the evolutionary history of seaweed species.     

Influence of temperature and daylength on population development ofAphis gossypii onCucurbita pepo

The life table parameters ofAphis gossypii Glover were evaluated in tow sets of experiments onCucurbita pepo. The first set was conducted at six constant temperatures (5°C increments from 10–35°C) with 12 h photophase. The second set of experiments was conducted at 6, 12, and 18 h photophase at 25°C. Nymphal survivorship was 100% at 15, 20, 25 and 30°C. However, it was 80 and 0% at 10 and 35°C, respectively. The optimum temperature for body length was 10°C, and body length decreased with increasing temperature.A. gossypii attained its optimum growth and reproduction at 25°C. At this temperature, the net reproductive rate (79.7), intrinsic rate of increase (0.496) and finite rate of increase (1.6) were largest while generation time (6.6 d) and population doubling time (1.4 d) were smallest. Temperatures above and below 25°C reduced the net reproductive rate, and the intrinsic and finite rates of increase. The intrinsic and finite rates of increase ofA. gossypii reared at 18 h photophase (0.53 and 1.7) were significantly higher than at 12 (0.43 and 1.5) and 6 h daylength (0.49 and 1.6).     

Influence of temperature on growth, reproduction and longevity of Moina salina Daday, 1888 (Cladocera, Moinidae)

This paper presents the results of a study of the effects oftemperature on the growth, reproduction and longevity of thecladoceran Moina salina, a species of potential use as livefood in marine aquaculture. The growth rate of M.salina increasedwith increasing temperature. Some parameters of development,such as length at death and the number of adult instars, werealso positively related to temperature. Other parameters (durationof juvenile and adult instars) decreased with increasing temperature,while the number of juvenile instars was unaffected. An increasein temperature resulted in a reduction in age at maturity anda decrease in the number of days between broods. The numberof young per female, the number of broods per female, the numberof youngper day of reproductive life, and the number of youngper brood, increased up to a temperature of 25°C. At 15and 20°C. substantial degeneration of eggs and/or embryosoccurred. Likewise, temperature affected the type of reproductioncarried out by sexual females. Temperature and longevity wereinversely correlated. It was concluded that temperature actsas a very important factor regulating the life cycle of M.salina.Temperature >30°C may correspond to sublethal levels,while a temperature of 15°C is considered to impose stress.The range 20–25°C is optimal for the development andreproduction of this species.     

Effects of pH,NH<Subscript>4</Subscript>-N concentration,temperature, and storage period on basidiospore germination in an ectomycorrhizal ammonia fungus <Emphasis Type="Italic">Hebeloma vinosophyllum</Emphasis>

Basidiospore germination in an ectomycorrhizal ammonia fungus Hebeloma vinosophyllum was stimulated by 10–500 mM NH₄Cl aqueous solution at pH 4.5–9.0, but not by pure water. The basidiospores germinated at 10°–35°C with an optimum at 25°–30°C. The highest germination percentage (83.0%) was observed in 100 mM NH₄Cl aqueous solution adjusted to pH 8.0 by KOH, when the basidiospores were incubated at a density of 10⁶ spores/ml at 30°C for 14 days. The percent germination value decreased with the increased duration of storage under both dry and wet conditions. Humidity and temperature affected the longevity of H. vinosophyllum basidiospores. The basidiospores maintained their germination ability longer under a dry condition than under a wet condition. The greatest longevity was accomplished by storage at 15°C under a dry condition.     

Energy budget for the larval development ofElminius modestus (Crustacea: Cirripedia)

Biomass (CHN), respiration rate and food uptake were estimated for the larval development ofElminius modestus at three temperatures (12, 18, 24°C). Mean values of dry weight, elemental composition and energy equivalents increased exponentially with the development from nauplius II to VI. Dry weight, elemental composition and energy content exhibited the highest values at 18°C. Respiration rates increased with the larval stages expressed by a power function, but increased logarithmically with the dry weight of the larvae. The cypris larvae showed a reduced respiration rate compared with nauplius VI. The ingestion rate was measured at a concentration of 100 cells ofSkeletonema costatum μl⁻¹. At 12 and 18°C ingestion rates increased exponentially and at 24°C by a logarithmic function. The fittings were used to estimate the energy budget ofE. modestus during larval development. The energy content of the larvae increased during the development from nauplius II to VI by a factor of 21 at 12°C, 25 at 24°C and 31 at 18°C. The estimated energy content of the freshly metamorphosed barnacle is 100 mJ (12°C), 130 mJ (24°C) and 150 mJ (18°C). The assimilation- (A/I) and gross growth efficiencies (K₁) increased strongly during the development from nauplius II to VI (A/I: 6–14% in nauplius II to 50–90% in nauplius VI; K₁: 4% in nauplius II to 75% in nauplius VI). The net growth efficiency (K₂) showed a relatively constant level ranging between 57 and 83%.     

Thermal ecotypes of amphi-Atlantic algae. II. Cold-temperate species (Furcellaria lumbricalis andPolyides rotundus)

Two species of cold-temperate algae from the North Atlantic Ocean,Polyides rotundus andFurcellaria lumbricalis, were tested for growth and survival over a temperature range of −5 to 30 °C. In comparisons of eastern and western isolates, bothF. lumbricalis, a North Atlantic endemic, andP. rotundus, a species having related populations in the North Pacific, were quite homogeneous.F. lumbricalis tolerated −5 to 25°C and grew well from 0 to 25°C, with optimal growth at 10–15 °C.P. rotundus tolerated −5 to 27°C, grew well from 5 to 25°C, and had a broad optimal range of 10–25°C. Both species tolerated 3 months in darkness at 0°C. In neither case could any geographic boundary be explained in terms of lethal seasonal temperatures, suggesting that these species are restricted in distribution by strict thermal and/or daylength requirements for reproduction. The hypothesis that northern species are more homogeneous than southern taxa in terms of thermal tolerance was supported. A second hypothesis, that disjunct cold-temperate species should be more variable than pan-Arctic species, was not supported.