Investigation of optimal conditions for foam separation of iturin,an antifungal peptide produced by Bacillus subtilis

An antifungal peptide, iturin, was produced by a newly-isolated Bacillus subtilis, which contains cyclic 7 d- and l-α amino acids and β-amino acids with aliphatic side chains. It consists of 6 derivatives with different length side chains. When the bacterium was cultivated in a jar fermentor, all the iturin produced was entrained in the foam. Thus, continuous separation and condensation of the product iturin is possible only by collecting the foam produced during fermentation. The controlling factors for foaming, namely the aeration rate, temperature and medium composition, especially the ratio of glucose to Polypepton, were investigated in relation to iturin production. The most effective conditions for the condensation of iturin were an aeration rate of 0.1 vvm, a temperature of 30°C, and a glucose to Polypepton ratio of 0.3–0.4. The total amount of iturin produced, and the ratio of peaks 3,4 and 5 in the iturin were maximized at 50 g/l of Polypepton by using a fermentor equipped with a basket-shaped agitation unit.     

Influence of pH and temperature on the expression of sboA and ituD genes in Bacillus sp. P11

Temperature and pH are key factors influencing the production of antimicrobial peptides. In this work, qRT-PCR methodology was used to demonstrate the effect of these two variables on sboA (subtilosin A) and ituD (iturin A) expression in Bacillus sp. P11, an isolate from aquatic environment of the Amazon. Bacillus sp. P11 was incubated in BHI broth for 36 h at 30, 37 and 42 °C, and the pH values were 6.0, 7.4 and 8.0. The production of subtilosin A and iturin A was confirmed by mass spectrometry. The sboA expression increased 200-fold when the initial pH was 8.0. In contrast, ituD expression was maximum at pH 6.0. Increased temperature (42 °C) was adverse for both genes, but ituD expression increased at 37 °C. Expression of sboA and ituD was strongly affected by pH and temperature and qRT-PCR proved to be a powerful tool to investigate the potential of Bacillus strains to produce subtilosin A and iturin A.     

The influence of process parameters in production of lipopeptide iturin A using aerated packed bed bioreactors in solid-state fermentation

The strain Bacillus iso 1 co-produces the lipopeptide iturin A and biopolymer poly-γ-glutamic acid (γ-PGA) in solid-state fermentation of substrate consisting of soybean meal, wheat bran with rice husks as an inert support. The effects of pressure drop, oxygen consumption, medium permeability and temperature profile were studied in an aerated packed bed bioreactor to produce iturin A, diameter of which was 50 mm and bed height 300 mm. The highest concentrations of iturin A and γ-PGA were 5.58 and 3.58 g/kg-dry substrate, respectively, at 0.4 L/min after 96 h of fermentation. The low oxygen uptake rates, being 23.34 and 22.56 mg O₂/kg-dry solid substrate for each air flow rate tested generated 5.75 W/kg-dry substrate that increased the fermentation temperature at 3.7 °C. The highest pressure drop was 561 Pa/m at 0.8 L/min in 24 h. This is the highest concentration of iturin A produced to date in an aerated packed bed bioreactor in solid-state fermentation. The results can be useful to design strategies to scale-up process of iturin A in aerated packed bed bioreactors. Low concentration of γ-PGA affected seriously pressure drop, decreasing the viability of the process due to generation of huge pressure gradients with volumetric air flow rates. Also, the low oxygenation favored the iturin A production due to the reduction of free void by γ-PGA production, and finally, the low oxygen consumption generated low metabolic heat. The results show that it must control the pressure gradients to scale-up the process of iturin A production.     

Optimization of laboratory cultivation conditions for the synthesis of antifungal metabolites by bacillus subtilis strains

In order to achieve the optimal number of colony forming units and a high level of antifungal metabolites synthesis, we carried out the periodic cultivation of the Bacillus subtilis BZR 336 g and Bacillus subtilis BZR 517 strains at various pH and temperature levels. In the experiment for determining the optimal temperature, the maximum titer of B. subtilis BZR 336 g bacterium (1.6–1.7 × 10⁹ CFU/ml) was recorded at a cultivation temperature of 20–25 °C. For B. subtilis BZR 517 strain, the temperature turned out to be optimal at 30 °C: the titer was 8.9 × 10⁸ CFU/ml. The maximum antifungal activity of B. subtilis BZR 336 g strain against the test culture of Fusarium oxysporum var. orthoceras was observed at a cultivation temperature of 20–25 °C; for B. subtilis BZR 517 strain, 25–30 °C. When determining the optimal pH level, it was found that a high titer of B. subtilis BZR 336 g strain cells was determined at pH 8.0 (2.7 × 10⁹ CFU/ml), for B. subtilis BZR 517 strain it was at pH 6.0–8.0 (1.0 × 10⁹ CFU/ml). The maximum antifungal activity was noted with the same indicators. Chromatographic and bioautographic analyses suggest that the synthesized antifungal metabolites belong to surfactin and iturin A. The data obtained in this research can be used in the development of the technology for the production of effective biofungicides to protect crops against Fusarium pathogens.     

Solid state cultivation of Streptomyces clavuligerus for cephamycin C production

Solid state cultivation of Streptomyces clavuligerus for cephamycin C production was carried out in a system consisting of wheat rawa 5 g; cotton seed deoiled cake 5 g; sunflower cake 0·5 g; corn steep liquor 1 g; MgSO₄.7H₂O 0·06 g; CaCO₃ 0·1 g; K₂HPO₄ 4·4 g; with initial moisture content of 80%, initial pH 6·5 and a fermentation temperature in the range 28–30°C. The fermentation cycle was about 5 days. Streptomyces clavuligerus growth was observed on the 2nd day and production of cephamycin C was initiated on 3rd day. Abundant mycelial growth was observed from the 3rd day and reached stationary phase by the 5th day. Cephamycin C was produced maximally at a rate of 15 mg/g substrate on the 5th day and was stable until the 30th day with only marginal decrease in titre.     

Effect of daylength and temperature on the larval diapause of the sunflower moth, Homoeosoma electellum

The effect of daylength and temperature on the regulation of the larval diapause of a central Missouri population of the sunflower moth, Homoeosoma electellum, was examined. Fully grown fourth-instar larvae exhibit a facultative diapause. Measurements of the effect of photoperiod on diapause induction revealed critical photoperiods of about 13 h 30 min light/day at 20°C, and between 11 h 45 min and 12 h light/day at 23°C. Third and fourth-instar larvae were shown to be the main sensitive stages for diapause determination. Daylength was also shown to be an important regulator of the rate of diapause development. A short day of LD 10:14 h permitted only a low rate of diapause development, whereas long days of LD 14:10 h and LD 16:8 h accelerated diapause development at 25 and 30°C. When long days were alternated with short days at 30°C the accelerating effect of long days on diapause development was not found. Systematic transfers of chilled diapausing larvae revealed an accelerated diapause development in groups transferred from 10 to 30°C LD 10:14 h, but diapause development was not accelerated in groups transferred from 10 to 30°C LD 16:8 h.     

The cultivation of oak seedlings inoculated with Tuber aestivum Vittad. in the boreal region of Finland

Despite recent findings, truffles are rarely found in Finland. In 2006, we began to explore the cultivation potential of Tuber aestivum/uncinatum in Finland. In 2006–2008, roughly 1,200 Quercus robur seedlings and 200 Q. pubescens seedlings were planted in 20 orchards. We aimed to challenge the Southern European (France) tree provenances of oak seedlings in a boreal climate. Additional winter coverings made up of fabric or plastic and twigs prevented the seedlings’ mortality even when the air temperature was below ?30 °C during the second winter. The results showed that the top soil temperature at 15 cm depth has to be above ?5 °C to guarantee the survival of seedlings. Q. pubescens was more sensitive to low soil temperatures than Q. robur. Morphological and PCR analysis of root samples collected over 2007–2010 confirmed the presence of T. aestivum in all orchards despite unfavorable temperatures during the winter time. The first T. aestivum sporocarps were found under Q. robur in October 2012 in the orchards established in 2006 on old agricultural land, showing truffle cultivation to be successful in the boreal climate.     

The impact of temperature on the production and fitness of microsclerotia of the fungal bioherbicide Mycoleptodiscus terrestris

The impact of growth temperature was evaluated for the fungal plant pathogen Mycoleptodiscus terrestris over a range of temperatures (20–36°C). The effect of temperature on biomass accumulation, colony forming units (cfu), and microsclerotia production was determined. Culture temperatures of 24–30°C produced significantly higher biomass accumulations and 20–24°C resulted in a significantly higher cfu. The growth of M. terrestris was greatly reduced at temperatures above 30°C and was absent at 36°C. The highest microsclerotia concentrations were produced over a wide range of temperatures (20–30°C). These data suggest that a growth temperature of 24°C would optimize the parameters evaluated in this study. In addition to growth parameters, we also evaluated the desiccation tolerance and storage stability of air-dried microsclerotial preparations from these cultures during storage at 4°C. During 5 months storage, there was no significant difference in viability for air-dried microsclerotial preparations from cultures grown at 20–30°C (>72% hyphal germination) or in conidia production (sporogenic germination) for air-dried preparations from cultures grown at 20–32°C. When the effect of temperature on germination by air-dried microsclerotial preparations was evaluated, data showed that temperatures of 22–30°C were optimal for hyphal and sporogenic germination. Air-dried microsclerotial preparations did not germinate hyphally at 36°C or sporogenically at 20, 32, 34, or 36°C. These data show that temperature does impact the growth and germination of M. terrestris and suggest that water temperature may be a critical environmental consideration for the application of air-dried M. terrestris preparations for use in controlling hydrilla.     

Heat induced infertility of boars: The inter-relationship between depressed sperm output and fertility and an estimation of the critical air temperature above which sperm output is impaired

Eight groups of Large-White gilts were each inseminated with different numbers of normal motile sperm, in the range 0.28–7.0 × 10⁹. A significant (P < 0.05) relationship between conception rate and the number of motile sperm inseminated was shown. This relationship can be used to equate output of motile sperm with levels of fertility of boars. The optimal number of motile sperm for conception following intra-cervical insemination was near 5 × 10⁹ and the threshold number, below which animals did not conceive, was c. 4 × 10⁸.In a second experiment, three Large-White boars were subjected to graded thermal treatment (air temperature was increased by 1°C per day for 20 days, from a basal level of 20°C to a maximal level of 40°C) and responses of ejaculate and other physiological characteristics were monitored. Scrotal surface temperature, respiration rate and rectal temperature increased (P < 0.05) beyond basal levels at air temperatures of 30°C, 33°C and 35°C, respectively. Motility of sperm in ejaculates decreased when air temperature reached 30°C and this response was presumed to reflect hyperthermia in epididymal tissues, consistent with increasing scrotal surface temperature at this same air temperature. Motility fell below a pre-treatment level of about 93%, to 19% (P < 0.05), 3 weeks after heating. Volumes of seminal plasma and gel in ejaculates were also lower (P < 0.05) following heating. Changes in daily sperm production were minor and, as a result, daily motile sperm production levels paralleled changes in motility. Proportions of abnormal types of sperm increased (P < 0.05) to maximal levels in the last week of heating and all returned to pretreatment values 5 weeks later. High proportions of sperm with kinoplasmic droplets appeared in ejaculates collected after heating (P < 0.05), evidence that epididymal cell types in the boar are sensitive to heat.As a result of heat treatment, normal motile sperm production decreased from control levels (1.28 × 10¹⁰·day^?1) to 0.15 × 10¹⁰·day^?1, 3 weeks after heating ceased. However, the results suggest that normal sperm output by Large-White boars can be maintained at air temperatures as high as 29°C.By relating the results of both experiments, it is concluded that fertility of the boars in the second experiment (if mated once daily) would be depressed for about 5 weeks after heat treatment ceased. The findings support many field reports which indicate a contribution of boars to lower conception rates of sows during and immediately following summer and the results can be used in formulating strategies to circumvent this widespread problem.     

Effect of two-stage temperature on pullulan production by Aureobasidium pullulans

The effect of a two-stage cultivation temperature on the production of pullulan synthesized by Aureobasidium pullulans CGMCC1234 was investigated. Pullulan production was affected by temperature; although the optimum temperature for pullulan production was 26°C, the optimal temperature for cell growth was 32°C. Maximum pullulan production was achieved by growing A. pullulans in a first stage of 32°C for 2 days, and then in a second stage of 26°C for 2 days. Pullulan production using these two-stage temperatures significantly increased: about 27.80% (w/w) compared to constant-temperature fermentation (26°C for 4 days). The morphology of the A. pullulans (CGMCC 1234) was also affected by temperature; the lower temperature (26°C) supported unicellular biomass growth. Results of this study indicate that fermentation using two temperature stages is a promising method for pullulan production.     

Zur fortpflanzungsbiologie von mesostoma ehrenbergii (Focke, 1836) (Turbellaria)

1. At temperature levels from 10 to 25°C animals from resting eggs produce subitaneous eggs independent on temperature. In contrast animals from subitaneous eggs produce subitaneous eggs dependent on temperature. At a high rate subitaneous eggs are only formed at temperature levels above 20°C.
2. Below 10°C no development occurs in the juveniles. At temperatures of 30/22°C (24.7°C) the first subitaneous eggs are formed after 6–9 days, at 14/9°C (10.7°C) they are formed after 34 days. At different temperature levels the developmental rate of the young is from 10.5 to 42 days. One generation extends over 16.5 (30/22°C) to 75 days (14/9°C). The average egg production is 10–20 subitaneous eggs or 30–60 resting eggs. The maximum egg production of one individual is 50 subitaneous eggs or 84 resting eggs. 50% of the animals have just formed resting eggs, before the juveniles are hatched. Resting eggs in the first egg-batch are formed 6–20 days later than subitaneous eggs. The duration of life is between 65 (30/22°C) and 140 days (19/13°C).
3. Young worms in resting eggs have a dormance period of at least 15–30 days.

At room temperatures (20°C) no juvenile in resting eggs hatches from water. By combining room and refrigerator (3.5°C) temperatures the hatching rate increases to a maximum of 85%. To reach a hatching rate of 50–65% the influence of low temperatures must be at least 30 days. At room temperatures 60% of the young in resting eggs hatch from mud covered with water. Combining high and low temperatures the hatching success is between 67 and 81%, where the highest percentage of the young may hatch at room temperature. Up to 90 days low temperatures cause a maximum hatching rate of 79%. It decreases to approximately 30% after 180 days. At high temperatures resting eggs preserved in 100% moist mud, survive for two months. By adding a period of low temperatures the hatching rate increases to a maximum of 52%. Low temperatures are survived for more than 6 months. Up to 30 days preservation at 3.5°C causes a maximum hatching rate of 61%, up to 12o days it decreases to 30%. At room temperature the young in resting eggs are not resistant against air-dried mud (30–40% rel. air moisture). Combining high and low temperatures air-dried mud is endured 1 month (hatching rate 5–14%). Preservation of 30–120 days at 3.5°C and 70% rel. air moisture result in a hatching rate of 43–61%. li]4. In the open air in Middle-Europe there occur 5–6 generations of M. ehrenbergii per life-cycle. The first generation hatches from resting eggs in May, where the production of subitaneous eggs is independent on temperature. All other generations up to October hatch from subitaneous eggs. The egg-production of those worms is dependent on environmental factors. In summer subitaneous egg production prevails, in autumn resting egg production. The abundance during the life-cycle is dependent on the number of animals which produce subitaneous eggs. Resting eggs are predestinated to endure periods of dryness and cold. The life-cycles of the species M. lingua and M. productum are different from those of M. ehrenbergii in length and in the number of generations. In both species 7 generations occur over 8 to 8.5 respectively 5.5 months. M. nigrirostrum only forms resting eggs. The life-cycle consists of one generation from February/March to May/June.     

The influence of the thermal environment and other early life events on growth rate of piglets during lactation

The effects of early life events on average daily weight gain from birth to day 21 (ADG) of suckling pigs kept at different room temperatures (15°C, 20°C and 25°C) from birth to weaning were investigated. Data were collected from litters born by 61 sows in a loose housing system. The ADG for piglets with low birth weight (estimated for birth weights below the 10% percentile) was estimated to be 20 to 30 g higher per day at room temperature 20°C to 25°C compared with 15°C. In contrast, the ADG during the lactation period decreased for larger piglets (estimated for birth weights above the 10% percentile) by 28 g/day at room temperature 25°C compared with 15°C. Thus, high ambient temperatures (20°C to 25°C) are favourable for the growth in smaller piglets during lactation. Neither latency to first suckle nor birth-induced hypoxia, measured as concentration of umbilical cord lactate, affected the growth rate of the piglets. Lowest rectal temperature during the first 24 h after birth had a long-term negative effect on ADG (P<0.05), so that piglets with a lowest rectal temperature of 32.8°C (10% percentile) had an ADG which was on average 19 g lower per day than piglets with a rectal temperature of 37.3°C (90% percentile). Our results showed that hypothermia at birth, low birth weight and high number of suckling piglets lead to reduced ADG during the suckling period. The results suggest that keeping the room temperature at 20°C during lactation to some extent could compensate for the otherwise negative effects of low birth weight on ADG in piglets without decreasing the ADG of high birth weight piglets. However, to avoid hypothermia in the smallest piglets it may be beneficial to increase the room temperature above 20°C during the farrowing period of loose housed sows.     

Black soldier fly (Diptera: Stratiomyidae) larval heat generation and management

Mass production of black soldier fly, Hermetia illucens (L.) (Diptera: Stratiomyidae), larvae results in massive heat generation, which impacts facility management, waste conversion, and larval production. We tested daily substrate temperatures with different population densities (i.e., 0, 500, 1000, 5000, and 10 000 larvae/pan), different population sizes (i.e., 166, 1000, and 10 000 larvae at a fixed feed ratio) and air temperatures (i.e., 20 and 30 °C) on various production parameters. Impacts of shifting larvae from 30 to 20 °C on either day 9 or 11 were also determined. Larval activity increased substrate temperatures significantly (i.e., at least 10 °C above air temperatures). Low air temperature favored growth with the higher population sizes while high temperature favored growth with low population sizes. The greatest average individual larval weights (e.g., 0.126 and 0.124 g) and feed conversion ratios (e.g., 1.92 and 2.08 g/g) were recorded for either 10 000 larvae reared at 20 °C or 100 larvae reared at 30 °C. Shifting temperatures from high (30 °C) to low (20 °C) in between (∼10-d-old larvae) impacted larval production weights (16% increases) and feed conversion ratios (increased 14%). Facilities should consider the impact of larval density, population size, and air temperature during black soldier fly mass production as these factors impact overall larval production.     

Effect of food and temperature on the reproduction of the blowfly, <Emphasis Type="Italic">Calliphora vicina</Emphasis> R.-D. (Diptera,Calliphoridae), a popular model object in biological research

Egg maturation in Calliphora vicina is known to occur within a wide range of temperatures, from 12°C to nearly 30°C (Vinogradova, 1991). Photoperiodism has no effect on this process. Some females enter diapause already at 20°C; their fraction increases at lower temperatures and reaches 100% at 6°C. Reproducing females with eggs can survive for a long time and even lay eggs at low temperatures (4–5°C). Experiments with C. vicina from Leningrad Province revealed some effects of the diet (liver or fish) and temperature on the fly reproduction. At 20 and 25°C, 7–10-day old females begin to oviposit, but at 20°C egg maturation is observed in 98% of females feeding on liver and in only 5% of females feeding on fish. On the liver diet, the mean daily fecundity is significantly correlated with the day of oviposition but not with the temperature. At 20°C a significant correlation is observed between the mean daily fecundity and both the day of oviposition and food. The total number of eggs laid by flies after feeding on fish is half that produced after feeding on liver. The optimal conditions for Calliphora vicina cultivation are a 16-h light day, temperatures within the range from 20 to 25°C, and liver as food.     

Effects of anaerobiosis on ethylene production, respiration and flowering in iris bulbs

Ethylene production of iris bulbs (Iris hollandica cv. Ideal) was very low. When stored at 30°C, production was 12–20 pmol C₂H₄ (kg fresh weight)^?1 h^?1. Higher temperatures (35°C, 40°C) enhanced the ethylene production; a treatment with 40°C for ca 7 days caused a 3 times higher ethylene production than at 30°. During anaerobic storage (in 100% N₂) ethylene production was equal to that of control bulbs. When after a 7 day period of anaerobiosis the N₂ was replaced by air, a burstlike ethylene production was observed. Twenty-four h after the replacement, ethylene production was equal to control values again. The effects of this production of ethylene on mitochondrial respiration and flowering were investigated. When mitochondria were isolated immediately after the anaerobic treatment (before the enhanced ethylene production) alternative pathway capacity was not detectable, a situation also occurring in control bulbs. When mitochondria were isolated 24 h after the end of the anaerobiosis (after the ethylene burst) uninhibited respiration did not change significantly, but a capacity of the alternative pathway was observed. The increase in alternative pathway capacity after anaerobiosis was partly inhibited by 2,5-norbornadiene (NBD), an ethylene antagonist. Fermentation occurred during anaerobiosis: ethanol concentrations increased during the treatment and decreased when air was supplied. When bulbs were exposed to ethanol vapour the alternative pathway was induced but only when very high ethanol levels in the bulbs were reached. The amount of ethanol accumulated in the bulbs during a 7 day anaerobic treatment was far too low to explain the observed induction of alternative pathway capacity. Flowering percentages were enhanced after a 24 h treatment with ethylene and after a 7 day anaerobic treatment. NBD significantly inhibited the effect of exogenous ethylene and of anaerobiosis on flowering. Ethanol was not able to induce flowering. The burst-like production of ethylene after anaerobiosis probably is responsible for the effects on respiration and flowering.     

Statistical optimization of antifungal iturin A production from Bacillus amyloliquefaciens RHNK22 using agro-industrial wastes

Biosurfactants are secondary metabolites with surface active properties and have wide application in agriculture, industrial and therapeutic products. The present study was aimed to screen bacteria for the production of biosurfactant, its characterization and development of a cost effective media formulation for iturin A production. A total of 100 bacterial isolates were isolated from different rhizosphere soil samples by enrichment culture method and screened for biosurfactant activity. Twenty isolates were selected for further studies based on their biosurfactant activity [emulsification index (EI%), emulsification assay (EA), surface tension (ST) reduction] and antagonistic activity. Among them one potential isolate Bacillus sp. RHNK22 showed good EI% and EA with different hydrocarbons tested in this study. Using biochemical methods and 16S rRNA gene sequence, it was identified as Bacillus amyloliquefaciens. Presence of iturin A in RHNK22 was identified by gene specific primers and confirmed as iturin A by FTIR and HPLC. B. amyloliquefaciens RHNK22 exhibited good surface active properties and antifungal activity against Sclerotium rolfsii and Macrophomina phaseolina. For cost-effective production of iturin A, 16 different agro-industrial wastes were screened as substrates, and Sunflower oil cake (SOC) was favouring high iturin A production. Further, using response surface methodology (RSM) model, there was a 3-fold increase in iturin A production (using SOC 4%, inoculum size 1%, at pH 6.0 and 37 °C temperature in 48 h). This is the first report on using SOC as a substrate for iturin A production.     

Conducting High acetic acid and temperature acetification processes by Acetobacter pasteurianus UMCC 2951

In this study Acetobacter pasteurianus strain UMCC 2951 was tested as a microbial starter to conduct acetification processes by repeatedly cultivation cycles under high temperature acetification at 40 ± 1 °C. Acid production and acetification rate increased with repeated cultures under high temperature acetification as adaptation period increased, but were still lower than acetification at 30 ± 1 °C. However, the addition of 0.15 % calcium chloride reduced the negative effects of 40 ± 1 °C on both acid production and acetification rate compared to 30 ± 1 °C. A strong decrease in fatty acids and phosphatidylethanolamine and increases in phosphatidylcholine and phosphatidylglycerol in cell membranes were found under high acid and high temperature acetification. In addition, transmission electron microscope images reveal a more compact cell wall when calcium chloride was added to the cultivation medium. The strategy used in this study confirmed that the use of acetic acid bacteria as microbial starters could be effective also at temperature above the optimal values, when acetification processes are managed through repeated semi-continuous cycles.     

Effects of low temperature on diapause termination and body colour change in adults of a stink bug, Plautia stali

Abstract. Diapause adults of Plautia stali Scott maintained at 20°C under short day conditions (LD 12:12 h) were exposed to four temperatures of 5–20°C to examine the effect on diapause development which was assessed in terms of oviposition. Diapause adults kept at 20°C under short day conditions changed their body colour gradually from brown to green and started egg laying after a prolonged preoviposition period. Those transferred to either 10 or 15°C also showed colour change but did not lay eggs. Bugs exposed to 5°C underwent neither body colour change nor oviposition and died more rapidly than those kept at higher temperatures. When 30-day-old diapause adults were chilled at 5, 10 or 15°C for 30 or 60 days and returned to 20°C and long day conditions (LD 16:8 h), the preoviposition period varied primarily depending on the chilling, but not on the temperature. On the other hand, when 60day-old diapause adults chilled for 30 days were observed at 20°C and long day conditions, their preoviposition period tended to be longer as the chilling temperature was lower In this case, a temperature of 10°C appeared to intensify diapause. Therefore, the effect of chilling on diapause development varied depending on the age at which insects were chilled. When chilled bugs were transferred to short day conditions at 20°C, most females failed to lay any eggs and some turned green, then after a while, some green bugs changed to brown again. These results indicate that bugs remained sensitive to short day conditions even after a 60-day chilling at 10 or 15°C.     

THE EFFECT OF SHORT PERIODS OF HIGH TEMPERATURE DURING DAY AND NIGHT PERIODS ON PEA YIELDS

Karr , E. J. (Ohio State U., Columbus), A. J. Linck , and C. A. Swanson . The effect of short periods of high temperature during day and night periods on pea yields. Amer. Jour. Bot. 46(2) : 91-93. Illus. 1959.—The effect of high temperatures during periods of relatively short duration (3-4 days) at various stages following anthesis at the first bloom node was studied in relation to yield of peas at this node. Except for the periods of differential temperature treatments, the plants were maintained in a standard environment room (24°C., light, 12 hr.; 15°C., darkness, 12 hr.). Three different temperature regimes during the treatment periods were studied: high day temperature—standard night temperature (32°—15°C.) ; standard day temperature—high night temperature (24°—30°C.) ; and high day and night temperatures combined (32°—30°C.). The data reveal the existence of a relatively well-defined thermal-sensitive period, with maximal sensitivity to high day temperatures occurring at about 9-11 days from full bloom, and maximal sensitivity to high night temperatures occurring about 6-9 days from full bloom. High night temperatures proved more critical, resulting in a maximal reduction of 25% in yield, as opposed to about 8% for high day temperatures. The effect of high day and night temperatures combined tended to be roughly additive.     

The effects of temperature and moisture on survival capacity,cuticular permeability,hemolymph osmoregulation and metabolism in the scorpion,Centruroides hentzi (banks) (scorpiones,buthidae)

• 1.1. The temperature and water relations of Centruroides hentzi females were investigated. At 12 and 72% relative humidity (RH), the lower and upper Lt₅₀ were -4.5 and 43.7°C, and -4.7 and 45.1°C, respectively. When exposed to high temperature stress, survivorship was significantly greater under mesic conditions.
• 2.2. Cuticular water loss was higher under xeric conditions (12% RH), ranging from 0.061 mg/cm²/hr at 30°C to 0.211 at 41°C.
• 3.3. Exposure to dry air (0–5% RH) resulted in a significant increase in hemolymph osmolality: from 441 to 688 mOsm over a 5 day period.
• 4.4. Mean oxygen consumption rates increased from 161.7 mm³/g/hr at 34°C to 541.6 at 44°C. ATPase activity was significantly higher in animals acclimated and tested at 35°C.