Temperature-dependent development of overwintering Sericinus montela Gray (Lepidoptera: Papilionidae) pupae and its validation

The developmental time and survival of overwintering Sericinus montela Gray pupae were studied at four constant temperatures (15.0, 20.0, 25.0, and 30.0 °C), 40 ± 10% relative humidity, and 10:14 h light:dark cycle. The developmental time of both sexes decreased with increasing temperature between 15.0 °C (70.18 days for females and 55.28 days for males) and 30.0 °C (19.60 days for females and 13.78 days for males). The development periods of females were longer than those of males at each constant temperature. The relationship between the developmental rate and temperature was fitted by a linear model and a nonlinear developmental rate model (Lactin 1). The mortality of overwintered S. montela pupae was lowest at 25.0 °C (16.7%) and highest at 15.0 °C (36.7%). The lower developmental thresholds were 12.38 and 12.16 °C for females and males, respectively. The distribution of development completion for females and males was described by the two-parameter Weibull distribution equation (r² = 0.87 for females and r² = 0.94 for males). The date for the cumulative 50% adult emergence was within one or two days of that predicted using the Lactin 1 model. The temperature-dependent developmental model for S. montela could be applied to predict the timing of spring emergence in different geographical locations and will be helpful in developing a full-cycle phenology model for S. montela.     

Effect of climate change on the occurrence of overwintered moths of orchards in South Korea

According to the Intergovernmental Panel on Climate Change (IPCC), the global mean surface temperature increased by 0.74°C between 1906 and 2005, and is expected to continue rising. In Korea, the temperature increased rapidly by 1.8°C between 1912 and 2010. The effect of global warming are expected to cause phenological changes in exothermic organisms such as insect pests which are highly dependent on temperature. In present study, we estimated the emergence time of three lepidopteran pests (Carposina sasakii, Grapholita molesta, and Phyllonorycter ringoniella) in apple orchards during 2000, 2020s, 2050s, and 2090s, by means of Representative Concentration Pathway (RCP) 8.5 climate change scenario. In comparison with 2000, the emergence of C. sasakii is predicted to occur 5.5 ± 0.49 days earlier in 2020s, 14.9 ± 0.40 days earlier in 2050s, and 40.0 ± 0.75 days earlier in 2090s; the emergence of G. molesta is predicted to occur 8.2 ± 0.36 days earlier in 2020s, 16.9 ± 0.40 days earlier in 2050s, and 49.7 ± 0.61 days earlier in 2090s; and the emergence of P. ringoniella is predicted to occur 9.0 ± 0.34 days earlier in 2020s, 20.5 ± 0.58 days earlier in 2050s, and 52.5 ± 0.63 days earlier in 2090s. The number of generations a year is expected to increase by 0.5–2.8 generations in 2050s, 1.3–6.7 in 2090s. Our predictions provide basic data for the development of insect pest management strategies in spring under conditions of global warming.     

Cold hardiness and sugar content in photo‐insensitive individuals of the cotton bollworm Helicoverpa armigera

Abstract A proportion of Helicoverpa armigera collected from fields in Okayama Prefecture (Western Japan; 34.6°N, 134.1°E) does not enter diapause when reared under a short days at 20 °C during the larval stages. However, diapause in such photo‐insensitive individuals can be induced when they are reared at moderately low temperatures, such as 15 °C, regardless of photoperiod. To determine whether such photo‐insensitive individuals can survive overwintering in fields, the present study compares the cold hardiness and sugar content between nondiapausing and diapausing pupae of photo‐insensitive individuals selected over several generations at 20 °C under a short day photoperiod (LD 10 : 14 h). Diapausing and nondiapausing pupae are obtained under the short days by rearing at 15 and 20 °C, respectively, during larval and pupal stages. These pupae are stepwise acclimated at a reduction of 5 °C every 5 days to 0 °C. Maximum survival periods of nondiapausing and diapausing pupae at 0 °C are approximately 30 and 90 days, respectively. Trehalose content in diapausing pupae increases, reaches a maximum level (1.95 mg 100 mg^?1 in males and 2.1 mg 100 mg^?1 in females) 28 days after exposure to 0 °C and then decreases. On the other hand, glucose content in diapausing pupae increases (maximum level: 0.32 mg 100 mg^?1 in males and 0.21 mg 100 mg^?1 in females) with decreasing trehalose content 42 days after exposure to 0°C. The decrease in trehalose content and the increase in glucose content may be linked to termination of diapause in H. armigera. These results suggest that, in Japan, the photo‐insensitive individuals can only survive in the mild winters of southern regions, and not in the severe winters of northern regions.     

Regulation of heat shock proteins in the apple maggot Rhagoletis pomonella during hot summer days and overwintering diapause

Abstract Developing larvae of the apple maggot Rhagoletis pomonella are frequently exposed to summertime apple temperatures that exceed 40 °C and, during their overwintering diapause, pupae are exposed to sub‐zero soil temperatures for prolonged periods. To investigate the potential involvement of heat shock proteins (Hsps) in response to these environmental extremes, the genes encoding Hsp70 and Hsp90 in R. pomonella are cloned and expression monitored during larval feeding within the apple and during overwintering pupal diapause. Larvae reared in the laboratory at constant temperatures of 25, 28 or 35 °C express Hsp90 but very little Hsp70. Larvae do not survive rearing at 40 °C. The temperature cycles to which larvae were exposed inside apples in the field, ranging 16–46.9 °C over a 24‐h period, elicit strong Hsp70 and Hsp90 expression, which begins at mid‐day and reaches a peak in late afternoon, coinciding with peak air and apple temperatures. Heat shock proteins are also expressed strongly by pupae during their overwintering diapause. Hsp70 is not expressed in nondiapausing pupae but is highly expressed throughout diapause. Hsp90 is constitutively expressed in both diapausing and nondiapausing pupae. Rhagoletis pomonella thus strongly expresses its Hsps during pupal diapause, presumably as a protection against low temperature injury, and during larval development to cope with natural temperature cycles prevailing in late summer.     

Freeze-tolerance adaptations,including haemolymph protein and lipoprotein nucleators,in the larvae of the cranefly Tipula trivittata

The terrestrial overwintering larvae of the cranefly Tipula trivittata were freeze tolerant (able to survive the freezing of their extracellular body fluids) throughout the winter and spring of 1982–1983 until they pupated in mid-May. The larvae were most cold tolerant (24 h lower lethal temperatures of ?25 to ?30°C) in late January and early February. Sorbitol, at a maximal concentration of ～0.4 M, was the only polyol determined to be present at high levels and sorbitol accounted for most of the seasonal fluctuation in osmotic concentration. Haemolymph inorganic ion (Na⁺, K⁺, Ca²⁺, Mg²⁺, Cl^?) concentrations did not vary seasonally.The supercooling points of the larvae remained constant at ?6 to ?7°C over the study period because of the presence of haemolymph ice nucleating factors. These ice nucleating factors consist not only of haemolymph proteins, as had been demonstrated previously in other insect species, but also lipoproteins.     

Comparison of cold hardiness and sugar content between diapausing and nondiapausing pupae of the cotton bollworm, Helicoverpa armigera (Lepidoptera: Noctuidae)

Abstract. To understand overwintering of the cotton boll worm Helicoverpa armigera, cold hardiness and sugar content are compared between diapausing and nondiapausing pupae. Diapausing and nondiapausing pupae reared at 20 °C under short and long photoperiods are acclimatized with a reduction of 5 °C per 5 days to 0 °C. When the acclimation temperature reaches 0 °C, the survival of diapausing pupae is assessed. The survival gradually decreases as the period of treatment progresses and approximately half survive for 112 days. However, nondiapausing pupae survive only 14 days after exposure to 0 °C. The surpercooling points of nondiapausing, diapausing and acclimatized pupae are approximately −17 °C. The major sugars contained in pupae are trehalose and glucose. Even though trehalose contents in diapausing pupae (initial level: 0.6 mg 100 mg⁻¹ fresh weight) increase significantly during cold acclimation and continue increasing until 58 days after exposure to 0 °C (maximum level: 1.8 mg 100 mg⁻¹), glucose is maintained at low levels (0.02 mg 100 mg⁻¹) for 56 days at 0 °C. However, glucose contents increase (maximum level: 0.8 mg 100 mg⁻¹) with decreasing contents of trehalose 84 days after exposure to 0 °C. Glycogen content gradually decreases during cold acclimation. When nondiapausing pupae are acclimatized with a reduction of 5 °C per 5 days to 5 °C from the beginning of pupation until the eyespots move, trehalose content increases (maximum level: 1.0 mg 100 mg⁻¹). Glucose contents in nondiapausing pupae increase before eclosion (0.09 mg 100 mg⁻¹). From these results, diapausing pupae of H. armigera can overwinter in regions where average winter temperatures are higher than 0 °C, but nondiapausing pupae cannot.     

Phenological analysis of spring colonisation of apple trees by Anthonomus pomorum

Adult apple blossom weevils, Anthonomus pomorum (L.) (Coleoptera: Curculionidae), leave their overwintering sites within and outside orchards to colonise apple trees in early spring. This study was conducted to characterize the temporal pattern of spring colonization of apple trees by overwintered weevils in relation to climatic conditions and apple bud stages, based on multiple mark-release-recapture experiments and field observations of foraging activities of weevils. The process of spring colonization of apple trees by overwintered weevils was related to thermal time totals above 0 °C. The dispersal into orchards initiated when the thermal time totals reached 161±27 (s.d.) degree-days (DD) calculated from January 1, or 117±16 DD from February 1. The daily dispersal speed of individual weevils within orchards was determined primarily by the maximum daily temperature, whereas crawling, feeding, and mating activities of weevils on apple trees were influenced by the mean evening temperature between 18:00 and 22:00 hours. On the other hand, the spring colonization of overwintered weevils was not synchronized with any specific apple bud stage, though the level of female foraging and reproductive activities on apple trees was related to apple bud stages. The overwintered weevils initiated dispersal into orchards over a wide range of bud developmental stages from little silver greenish tip B (51) to the mouse-ear stage C3 (54). These findings are discussed in relation to the ecology and pest management of this insect.     

Effect of hypoxia and its repercussions in packing pupae of the parasitoid Diachasmimorpha longicaudata (Hymenoptera: Braconidae) for shipment

Hypoxia periods of 6, 12, 24, 48, and 72?h combined with temperatures of 15°C, 20°C and 25°C were applied to Diachasmimorpha longicaudata pupae in packaging conditions. Alternating temperatures of 26–20–26°C were applied to pupae in three sequential 4-h periods less than 12?h of hypoxia, and the effect of hypoxia on the pupae was evaluated under ambient conditions in commercial shipping. The emergence, longevity, fecundity and flight ability of adult parasitoids were recorded. The duration of hypoxia (>24?h) and the higher temperature (25°C) significantly reduced the emergence and longevity of adults. The different temperatures, including the variation in temperature combined with hypoxia, showed no significant effect on fecundity or flight ability. The temperature and humidity recorded during commercial shipping under hypoxia did not show any effect on the emergence of parasitoids. As a consequence, hypoxia was only notably significant after 24?h, which occasionally occurs in practical packaging processes. The use of hypoxia for shipping D. longicaudata pupae can be widely recommended, but long shipping periods and high temperatures should still be avoided.     

A study on intra-particle diffusion effects in enzymatic reactions: glucose-fructose isomerization

In this work different aspects of the glucose-fructose enzymatic isomerization, using immobilized glucose isomerase, are studied and quantified. Reaction temperatures range from 40?°C to 60?°C. Intra-particle effective diffusivities (D _e), determined after uptake experiments, are between 1.20?×?10^?6?cm²/s, at 40?°C, and 2.52?×?10^?6?cm²/s, at 60?°C. The estimated energy of activation for diffusion (E _aD) is 7.71?kcal/mol. No significant adsorption of the sugars on the support gel matrix is observed. Crushed particles (φ = 150–350?μ) are used during kinetic experiments. For this range of particle diameters, inherent kinetics is approached. A reversible Michaelis–Menten rate equation is fitted to the data, providing the following parameters at pH = 7.0: k ₀ = 2.15?×?10^?6?g/IU/s; E _a/R = 8998?K. Glucose (K _G) and fructose (K _F) affinity constants are essentially the same, ranging from 0.190?M, at 40?°C to 0.305?M, at 60?°C. The thermodynamic equilibrium constant is determined for the three temperatures, and the heat of reaction, estimated from a Van't Hoff plot, is ΔH = 1682?cal/mol. Independent experiments, where the reaction occurs in the presence of significant intra-particle mass transfer resistance, are used as validation tests.     

Cold tolerance characteristics of Korean population of potato tuber moth,Phthorimaea operculella (Zeller), (Lepidoptera: Gelechiidae)

Potato tuber moth (PTM), Phthorimaea operculella (Zeller), (Lepidoptera: Gelechiidae) is an invasive insect pest damaging solanaceous crops. We measured the supercooling point (SCP) and survival at low temperature of different development stages to determine which would be capable of overwintering in the Korean climate and adapting to low temperatures. The SCP ranges from ?23.8°C of the egg to ?16.8 of fourth instar larvae (L4). After short periods of low temperature acclimation in L3 (third instar larva), L4 and prepupae, only the prepupal stage showed a significant lowered SCP from ?20.78 to ?22.37°C. When exposed to different subzero temperature for two hours the egg turned out to be the most cold tolerant stage showing LT₅₀ of ?21.7°C followed by the pupal stage with ?15.89°C. One hundred percent mortality was observed when the larvae or adults were exposed to temperatures below ?15.1°C even for a period as short as 2 h. The results suggest that PTM pupae and egg would be the main overwintering stage in Korea where winter temperature does not drop below ?15°C.     

Sexual dimorphism in photoperiodic plasticity of body mass in the green dock leaf beetle <Emphasis Type="Italic">Gastrophysa viridula</Emphasis> (Coleoptera,Chrysomelidae)

Sexual dimorphism in body mass was studied in prepupae, pupae and immature adults of the green dock leaf beetle Gastrophysa viridula under a constant temperature of 24°C and two photoperiods (12L:12D and 22L:2D). Females were significantly heavier compared to males at all the three developmental stages; just after emergence from pupae they weighed, on average, 11.4 mg, while males—10.3 mg. Sex differences in photoperiodic body mass plasticity were revealed: under short-day conditions pupal and adult mass in females was significantly higher compared to long day, but not in males. Such a response to short day (the factor inducing reproductive diapause in this species) is likely to promote accumulation of greater amount of nutrients by females which is necessary for earlier oviposition after overwintering.     

Low temperature storage effects on two olive fruit fly parasitoids

Effects of cold storage temperatures and storage duration were evaluated for Psyttalia humilis (Silvestri) from Namibia and Psyttalia ponerophaga (Silvestri) from Pakistan, braconid parasitoids of Bactrocera oleae (Rossi) imported to California, USA. Immature stages of P. humilis were exposed to 4, 6, 8, 10, or 12 °C for 1, 2 or 4 months (pupa only at 4 and 12 °C) and then held at 24 °C for adult emergence. Less than 5 % of parasitoids in the 4–8 °C treatments survived, regardless of storage duration. At the 10 °C treatment, adult survival decreased with increased storage duration, but increased with advancing developmental stages. Survival was not affected at the 12 °C treatment. Adult P. humilis were exposed to 6, 8, 10 °C for short periods (1, 2, 4, or 6 weeks) or ambient winter conditions in Parlier, California, USA (about 9 °C). Regardless of storage temperature, P. humilis reproduction was reduced after storage of four and six weeks. Similarly, after 4 months at ambient winter temperatures, P. humilis reproduction was reduced. Psyttalia ponerophaga pupae stored at 6 °C for 41–97 days had decreased survival and increased developmental time. Survival of P. ponerophaga pupae ranged from 13.9–52.1 %, whereas under similar storage conditions survival of P. humilis was <0.7 %, suggesting P. ponerophaga is more cold tolerant than P. humilis.     

The effect of temperature and light conditions on diapause induction in a Korean population of Neoseiulus womersleyi Schicha (Acari: Phytoseiidae)

To determine the condition for diapause induction of a Korean population of Neoseiulus womersleyi, combinations of constant temperatures (14, 16, 18, 20 and 25 °C) and photoperiods (0, 8, 10, 12, 14, 16 and 24 h photophase) were used from egg to adult emergence. Diapause induction was determined by reproductive cessation of adult females. Lower temperature and shorter photophase resulted in higher diapause induction. Critical photophases for diapause induction were 10 and 12 h at 18 and 16 °C, respectively. Diapause-induced N. womersleyi adult females consumed significantly fewer eggs of the two-spotted spider mite, Tetranychus urticae, than non-induced females. Field monitoring of N. womersleyi showed that there was no egg-bearing female after 282 Julian date, while a model estimated complete diapause induction at 288 Julian date. Diapause of this predatory mite occurred approximately 2 weeks before diapause of its main prey, T. urticae, in Korean apple orchards. Further study perspectives are discussed relative to the spider mite biological control system in fruit orchards.     

The effects of water temperature and hormone treatments on circulating LH and ovulation in tench (Tinca tinca)

The effectiveness of three hormone treatments commonly used for artificial reproduction of tench was evaluated under three thermal regimes, with focus on the need for dopamine antagonist. Mature females were divided into nine groups (n?=?8) and gradually exposed, over a 24?h period, to three temperature regimes: cold (18.1?±?0.02?°C), optimal (22.05?±?0.03?°C), and warm (26.3?±?0.01?°C). Each temperature regime comprised three experimental groups injected with one of three hormone treatments: carp pituitary extract (CPE; 3?mg?kg^?1); [D-Arg⁶, Pro⁹, NEt]-sGnRH (10???g?kg^?1); and [D-Arg⁶, Pro⁹, NEt]-sGnRH (10???g?kg^?1)?+?metoclopramide (20?mg?kg^?1) (combined treatment). No differences were found between ovulation induction (ovulation rate????75?%) with sGnRHa alone and with the combined treatment; whereas CPE at cold and warm water temperatures was significantly less effective (P?<?0.05) than above mentioned treatments. Administration of sGnRHa alone induced a gradual increase in luteinizing hormone (LH) levels with LH peaks close to ovulation, in contrast to the immediate LH surge with high LH levels throughout the entire study observed with the combined treatment under all thermal regimes. LH levels induced by GnRHa alone were significantly lower (P?<?0.05) at all temperatures compared to the combined treatment, with the exception of the final sample at 26?°C, when no difference was recorded. Based on these results we recommend the application of sGnRHa without the addition of dopamine antagonist as a reliable method for inducing ovulation in tench under suboptimal temperature conditions.     

Differences in pupal cold hardiness and larval food consumption between overwintering and non‐overwintering generations of the common yellow swallowtail,Papilio machaon (Lepidoptera: Papilionidae), from the Osaka population

To clarify differences in pupal cold hardiness and larval food consumption between overwintering and non‐overwintering generations of the common yellow swallowtail, Papilio machaon, we reared larvae from the Osaka population under photoperiods of 16 h light : 8 h dark (LD 16:8) (long day) or LD 12:12 (short day) at 20°C. We examined the relationship between food consumption and weight during the final larval stadium and pupae, and measured the pupal supercooling point (SCP). Although the ratio of assimilation to consumption did not differ significantly between photoperiods, the ratio of assimilation to pupal weight differed significantly between individuals reared under long and short days. All diapausing pupae were brown, whereas 56% of non‐diapausing pupae were green with the remainder brown. The mean pupal body length (L), dorsal width (W₁) and lateral width (W₂) were larger in non‐diapausing than in diapausing pupae, and the W₁/L and W₁/W₂ ratios differed significantly between non‐diapausing and diapausing pupae. SCP was approximately –20°C and did not differ among pupae 5, 15 and 30 days after pupation under long‐day conditions. However, under short‐day conditions, mean SCP gradually decreased, stabilizing at approximately –24 to –25°C by 30 days after pupation. After freezing, some diapausing pupae emerged as adults, whereas all non‐diapausing pupae died. Both egestion and assimilation were greater under long‐day conditions. The results revealed that pupae of this papilionid exhibit seasonal polyphenism in physiological and morphological traits. Energy from food appears to be expended on increasing cold hardiness in the overwintering generation and on reproduction in the non‐overwintering generation.     

Diapause development in early and late emerging phenotypes of Delia floralis

The turnip fly, Delia floralis Fall6n （Diptera： Anthomyiidae） is an important insect pest of brassica vegetable crops in the holarctic region. Different populations have strongly varying temperature requirements for fly emergence, a challenge for accurate prediction of activity. This study focused on diapause development in one early and one late emerging phenotype. The physiological state after various treatments was deduced from emergence data. Our results showed a slow diapause progression at chilling conditions for both populations and diapause ended about 7 months after pupae were formed for the early population. For the late population held at 4℃ diapause did not end, no matter how long the duration of chilling. These pupae required a period with elevated temperatures above 6~C to continue development. At constant non-chilling conditions （18℃） from the time pupae were formed both populations completed diapause most rapidly. These results indicate that chilling delayed, rather than accelerated development and was not a prerequisite for diapause development. For post-diapause, results indicated a linear relationship between rate of development and temperature within the range of 6-18℃and a theoretical base temperature for development of about 2℃ for both populations. In conclusion, D. floralis pupae are in diapause throughout a long winter period, and delayed emergence of the late population appears to be caused by prolonged diapause regulated by a developmental temperature threshold. The study has added information on the biology of turnip fly populations, a prerequisite for improved pest control.     

Influence of larval rearing temperature on the quality of cold‐stored Oomyzus sokolowskii Kurdjumov (Hymenoptera: Eulophidae)

Oomyzus sokolowskii, an important parasitoid of Plutella xylostella, has great potential for use in biological control. Storage at suboptimal temperature is valuable for increasing the shelf‐life of insect parasitoids. In this study, O. sokolowskii larvae were reared at 30/25, 25/25 and 25/20°C light/dark (65 ± 5% RH, 16 : 8 h L : D) until pupation. The pupae were then cold‐stored at 4 ± 1°C (60 ± 5% RH, full darkness). The pupae were removed out from the storage at 10, 20, 30 and 40 days after storage (DAS) and maintained at 25 ± 2°C until adults emerged or pupae died. Quality of the emerging adults and their F₁ offspring were assessed. Incidence of parasitism by O. sokolowskii was higher at 30/25°C than at 25/20°C. Cold storage of O. sokolowskii pupae greatly affected the fitness of the parasitoid: adult emergence rates were lower in the 40 DAS treatment than in other treatments; when O. sokolowskii larvae developed at 25/25°C, female proportions of the emerged adults were lower in the 40 DAS treatment than in the 0 and 10 DAS treatments. Larval rearing temperature mildly affected the adult emergence rate, post‐storage developmental time and female proportion with a few exceptions. Number of parasitoids emerged per host pupa, and incidence of parasitism by the females were neither affected by larval rearing temperature nor cold storage duration. Trans‐generational effects on F₁ offspring were evident in adult emergence rate, egg‐adult developmental time and female proportion which were negatively affected by long duration of storage (40 days), but not by larval rearing temperature with a few exceptions. In conclusion, O. sokolowskii pupae could be stored at 4°C for up to 30 days without significant fitness loss.     

Ecdysteroids and diapause in pupae of Heliothis punctiger

Most pupae of H. punctiger enter diapause when reared at 19°C, 12L:12D. When pharate pupae were treated for only 12 hr at 28°C about 50% developed at 19°C. The proportion of non-diapausing pupae increased as the temperature at which the pharate pupal stage was spent increased.The quantity of injected 20-hydroxyecdysone necessary to promote development in diapausing pupae varied from about 1 μg g^?1 soon after pupation to about 4 μg g^?1 after 50 days. It fell somewhat after 150 days.Removing brains from non-diapausing pupae showed that the brain secreted its hormone at the time of pupation (or just before). However, if the pupae were kept at 19°C development did not occur unless the brain remained in situ for at least 20 hr at 28°C. Implanting brains from non-diapausing pupae into diapausing ones had no measurable effect.These results may be explained by postulating that the prothoracic gland is ‘activated’ by exposure to high temperature, but that it reverts to inactivity over a period at 19°C. The ‘active’ gland must then be stimulated by brain hormone for a long period to trigger secretion of its hormone, which results in development. Diapause is thus the result of the failure of the prothoracic gland to secrete.     

Optimization of propionic acid production in apple pomace extract with Propionibacterium freudenreichii

Abstract

Sequential optimization of propionate production using apple pomace was studied. All experiments were performed in a static flask in anaerobic conditions. Effect of apple pomace as nitrogen source against conventional N sources (yeast extract, peptone) was studied. The double increase was observed in propionic acid production while using yeast extract and peptone (0.29?±?0.01?g/g), as against the use of only apple pomace extract (APE) (0.14?±?0.01?g/g). Intensification of propionic acid fermentation was also achieved by increasing the pH control frequency of the culture medium from 24-(0.29?±?0.01?g/g) to 12-hour intervals (30?°C) (0.30?±?0.02?g/g) and by increasing the temperature of the culture from 30 to 37?°C (12-hour intervals of pH control) (0.32?±?0.01?g/g). An important factor in improving the parameters of fermentation was the addition of biotin to the medium. The 0.2?mg/L dose of biotin allowed to attain 7.66?g/L propionate with a yield of 0.38?±?0.03?g/g (12-hour intervals of pH control, 37?°C).     

Variation in the chemical composition of Capsosiphon fulvescens with area and during the harvest period

In this study, variations in Capsosiphon fulvescens composition with area and during the harvest period were assessed by analysis of crude protein, ash, and carbohydrate content. C. fulvescens in Janghung showed the highest crude protein content in December and the highest carbohydrate content in February. Changes in total amino acid, free amino acid, and fatty acid content were observed between December and February. Total amino-acid content of Janghung samples tended to decrease over the course of the harvest period, from 35.7?±?0.2?g 100?g^?1 in December to 32.9?±?0.2?g 100?g^?1 in February. Total amino-acid content in Janghung and Gohung samples was higher than that in Wando, except for glutamic acid. Significant increases in the major fatty acids (C12:0, C14:1 n-5, C18:0, C18:1 n-9, C18:2 n-6, C18:3 n-3, C20:0, C20:1 n-9, C22:1 n-9, C22:6 n-3, and C24:1 n-9) in Janghung were observed as the harvest period progressed. Fructose was the most abundant and glucose the second most abundant in the monosaccharide composition profiles, while galactose, ribose, and lactose were present in low quantites and mannitol, fucose, and arabinose were not detected.