The effect of constant darkness on the content of adipokinetic hormone, adipokinetic response and walking activity in macropterous females of Pyrrhocoris apterus (L.)

Abstract.  Changes in the content of adipokinetic hormone (AKH), the adipokinetic response and the walking activity of 10-day-old adult macropterous females of the firebug, Pyrrhocoris apterus (L.), reared under long-day (LD) photoperiod (LD 18 : 6 h) are compared with those exposed for 3 days to constant darkness (DD). Diel changes of all the parameters studied in LD females persist in females kept in constant dark. A positive correlation exists between diel changes of AKH content in the central nervous system (CNS) in the LD and DD females, and a negative correlation in the AKH level in haemolymph and walking activity. In addition, there is a positive correlation between diel changes of AKH level in haemolymph and walking activity in macropterous females reared under LD conditions, as well as in those transferred to constant darkness. The data suggest that there is some feedback between the release of AKH from CNS into the haemolymph and walking activity in macropterous females. Preliminary studies on the simultaneous expression of mRNA for the period gene and a positive reaction to an antibody against AKH in the same corpus cardiacum cells suggest that the period gene may be involved in regulating the AKH content in this gland.     

Adipokinetic hormone content of the corpora cardiaca in gregarious and solitary migratory locusts

Abstract. The adipokinetic hormone (AKH-I and AKH-II) content of the corpora cardiaca from adult males of crowded (gregarious) and isolated (solitary) Locusta migratoria migratorioides (Reiche & Fairmaire) was quantified by reverse-phase high-performance liquid chromatography.Significantly less total hormone was found in the corpora cardiaca of crowded locusts than in those glands of isolated locusts at the age of 12–19 days after fledging.The ratio of AKH-I/AKH-II was higher in crowded than in isolated locusts at this age.From the age of 12–19 days to that of 25–30 days, AKH content increased significantly in the corpora cardiaca of crowded locusts, but no such increase was found in the glands of isolated locusts, and at 25–30 days there were no significant differences in the AKH content of the glands from crowded and isolated locusts.     

Preliminary characterization of glycogen phosphorylase activating hormone and adipokinetic hormone from Manduca sexta corpora cardiaca

ABSTRACT. An attempt was made to separate glycogen phosphorylase activating hormone (GPAH) and adipokinetic hormone (AKH) from the corpora cardiaca (CC) of the moth Manduca sexta (Lepidoptera: Sphingidae) by separating extracts of CC on various chromotographic media, but it was not possible to conclude whether GPAH and AKH are activities of one or of two different peptides. Both activities elute together from glass beads, from Sephadex G-25 and from Sephadex LH-20 columns. In the separation experiments with glass beads and G-25 the activities eluted as a single peak, but using LH-20 we found two peaks exhibiting both activities. The major peak eluted at 1.25 × V_t, which is very similar to locust AKH, while the smaller second peak eluted at O.74 × V _t. Cross injections of CC extracts from M. sexta into Locusta migratoria and CC extracts from L. migratoria into M. sexta suggest that GPAH and the AKH from M. sexta are not identical with the decapeptide AKH from locusts.     

Juvenile hormones: Their role in the regulation of the pheromonal communication system of the armyworm moth,Pseudaletia unipuncta

Recently, much effort has been devoted to the elucidation of the neuro-endocrine mechanisms regulating the biosynthesis and emission of sex pheromones in the Lepidoptera. The available data indicate that the hormonal mechanisms involved vary considerably among species. For example, compelling evidence that juvenile hormones (JH) play a role in the control of sex pheromone production has been presented only for the armyworm moth, Pseudaletia unipuncta. In this species, females that are allatectomized at emergence neither produce nor release pheromone, but both activities are restored following replacement therapy with synthetic JH. However, injection of synthetic JH into neck-ligated females does not induce pheromone biosynthesis, whereas treatment with either a brain homogenate or synthetic PBAN results in a rise in the pheromone titer. These results indicate that the role played by JH is an indirect one and that the tropic factor is a PBAN-like substance. Studies on in vitro JH biosynthesis by isolated corpora allata of P. unipuncta have shown that the low JH output observed early in the life of adult females coincides with the absence of both calling behavior and pheromone production. The subsequent increase in the rates of JH biosynthesis correlates with the onset of pheromone production and release. We have therefore proposed that JH titers must pass a threshold level before the circadian release of PBAN and calling behavior can begin. Furthermore, recent experiments suggest that the continuous presence of JH is necessary for calling behavior to be maintained once initiated. Lastly, we present data suggesting a role for JH or JH acids in the receptivity of P. unipuncta males to the female sex pheromone. © 1994 Wiley-Liss, Inc.     

Characterization and baculovirus-directed expression of a myosuppressin encoding cDNA from the true armyworm, Pseudaletia unipuncta

Insect myosuppressins are a highly conserved sub-family of peptides which are primarily characterized by the ability to suppress contraction of visceral muscles in a variety of insect species. We have isolated a cDNA from the true armyworm, Pseudaletia unipuncta, that encodes a prohormone containing a peptide identical to ManducaFLRFamide. We have shown that this myosuppressin gene appears to be expressed in late larval and adult insects. In Manduca sexta, a number of extended-FLRFamide peptides have previously been purified including ManducaFLRFamide, F7D (DPSFLRFamide), F7G (GNSFLRFamide) and two larger peptides F24 and F39 that contain the shorter ManducaFLRFamide sequence at their C-terminus. Comparison with the true armyworm prepropeptide characterized here identifies F24 and F39 as partially processed products from the same precursor. Expression in the true armyworm was shown by in situ hybridization to occur in over 150 cells throughout the adult brain and nerve cord, and also to occur in both open and closed endocrine type cells of the gut. Overexpression of the P. unipuncta FLRFamide cDNA from a baculovirus vector in cabbage looper caterpillars was used to assess the potential for myosuppressin expression as a means of enhancing virus efficacy. Viral expression of the armyworm prohormone cDNA resulted in raised levels of RFamide-like products in the hemolymph of infected insects, but the products were found to be chemically distinguishable from authentic mature peptide and probably represent partially processed hormone.     

Substrate utilization and flight speed during tethered flight in the locust

Mature laboratory locusts normally exhibit a characteristic pattern of change in flight speed with time. They fly at high speed for the first few minutes, during which carbohydrate forms the major fuel, but then slow to a cruising speed when lipid is used almost exclusively. Locusts flown for 30 min, rested for 2hr, and then reflown, exhibit an identical pattern of flight, even though they oxidise only half the amount of carbohydrate used in the first flight. The injection of adipokinetic hormone before the first flight elicits a low initial flight speed for 10 to 15 min but then the locusts accelerate to a constant higher speed. The injection of hormone before the second flight, when blood lipid levels are already high, reduces the utilization of carbohydrate by the flight muscles dramatically but results in constant high-speed flight.     

Unique virus morphogenesis and cytopathology of a baculovirus (hypertrophy strain) in larva of the armyworm,Pseudaletia unipuncta

Nuclear polyhedrosis in tracheal cells caused by the hypertrophy strain of a nuclear polyhedrosis virus (HNPV) has many morphological and developmental features that distinguish it from that caused by the typical strain (TNPV). The most obvious difference is the morphogenic sequence due to the relatively slow virogenic development in HNPV-infected cells, in which are found extensive membranous profiles similar to viral envelopes, electron dense granules, large fibrous bodies, and microtubules. These structures also occur in TNPV-infected cells but are far less abundant and conspicuous. Fibrous bodies found in the cytoplasm and nucleus appear to be morphologically identical. Cellular distortion in a hypertrophied tracheal cell is seen as tearing of mestracheon folds between cells, separation of septate desmosomes, and attenuation in the cellular sheath.     

Hormonal control of lipid synthesis in the fat body of the adult female tsetse fly, Glossina morsitans

Aqueous extracts of brain, thoracic ganglion or corpora cardiaca of female Glossina morsitans were shown to contain a substance which inhibited the synthesis of lipid from l[U-¹⁴C] leucine by fat cells incubated in vitro. The highest concentration of this substance was found in the corpora cardiaca; approximately 1 × 10^?6 gland pairs μl^?1 were required for maximum inhibition. At concentrations greater than 1 × 10^?4 gland pairs μl^?1 the lipid synthesis inhibiting factor (hereafter referred to as the LSIF) was inactivated by the presence of a substance which could be removed by gel filtration. The concentration of LSIF in the corpora cardiaca and midbrain varied throughout the reproductive cycle of the female. Net release of LSIF from the midbrain occurred between the 2nd and 7th day of the 9-day reproductive cycle. Net release from the corpora cardiaca began on day 5 and continued until the end of the interlarval period on day 9. Results are consistent with the hypothesis that LSIF is synthesised mainly in the medial neurosecretory cells of the midbrain whereas the corpora cardiaca are the site of storage and release into the haemolymph. LSIF was present in midbrain and corpora cardiaca extracts from male G. morsitans but at lower concentrations than in females. No variation in LSIF concentration could be correlated with the feeding cycle. LSIF activity was not detected in fresh haemolymph but was found at high concentration in boiled haemolymph, suggesting the presence of an inhibitor which was inactivated at high temperature. Preliminary investigations into the nature of LSIF have shown it to be inactivated by proteolytic enzymes and to be recoverable in a single peak from a Sephadex G15 column.Results support the view that LSIF is a peptide hormone which, in conjunction with an inhibitor, controls the lipid synthetic ability of the fat cells of the adult female tsetse fly throughout the reproductive cycle.     

飞行对粘虫体内甘油酯积累与咽侧体活性的影响

研究了粘虫Mythimna separata (Walker)成虫飞行对甘油酯的恢复、保幼激素的滴度及飞行肌降解的影响, 结果表明,不同日龄粘虫的飞行活动对其能源物质的积累及保幼激素分泌产生不同的影响。1日龄蛾的飞行对粘虫这两方面产生的影响最大,其飞行个体能源物质的积累明显高于未飞行的对照个体; 3日龄飞行个体的能源物质积累与对照相当; 但5日龄飞行个体则很难达到对照水平。1日龄飞行个体咽侧体活性在36 h后明显高于对照,60 h后已是对照的10倍,108 h达到其峰值; 3日龄飞行个体咽侧体的活性稍高于对照,但差别不显著; 5日龄飞行个体的咽侧体活性则稍低于对照。不同日龄飞行对飞行肌的降解也产生不同的影响。1日龄飞行个体的飞行肌在飞行后6 天已经明显低于对照。3、5日龄的飞行活动对其飞行肌降解的影响不明显。因此推测,粘虫咽侧体活化的关键时期可能在羽化后1～3 天之间。     

Hormone stimulated lipolysis and proline synthesis in the fat body of the adult tsetse fly, Glossina morsitans

G. morsitans fat cells incubated in vitro with l-[U-¹⁴C]-leucine incorporated the radiolabel, mainly into triglycerides. Aqueous extracts of corpora cardiaca, midbrain, or thoracic ganglion stimulated the release of radiolabelled material from prelabelled fat cells in vitro. Corpora cardiaca extracts were the most active, approx. 1 × 10^?3 gland pairs/μl elicited the maximal response. At concentrations above 1 × 10^?3 gland pairs/μl the activity of corpora cardiaca extracts was inhibited by a substance which could be removed by gel filtration. The stimulatory factor in nervous-tissue extracts was destroyed by proteolytic enzymes and was recoverable in a single peak by Sephadex G15 gel filtration. Results suggest that it is a peptide hormone produced mainly by the median neurosecretory cells of the midbrain with the corpora cardiaca being the site of storage and release. No hormone was detectable in fresh haemolymph, but it was found at high concentration in boiled haemolymph, implying the presence of a heat labile inhibitor.Under the in vitro conditions used the hormone stimulated the synthesis of proline from alanine and the hydrolysis of triglycerides to free fatty acids. The probable functions of the hormone are to stimulate proline synthesis in response to demand for flight and/or to mobilise lipid for larval nutrition. The relative importance of these apparent functions in vivo could not be determined.     

The inhibition of lipid synthesis in vitro in the locust, Schistocerca gregaria, by factors from the corpora cardiaca

ABSTRACT. The rate of lipid synthesis from [¹⁴C]acetate in fat body from Schistocerca americana gregaria has been studied in vitro. Maximum incorporation is found on days 6–10 in adults and day 4 of the fifth stadium. The label appeared in the fatty acid components of triacyl-glycerol, diacylglycerol and phospholipid.
Lipid synthesis in vitro was inhibited by extracts of corpora cardiaca, and such inhibition was most marked (up to 85%) in fat bodies from insects at stages where fatty acid synthesis was greatest. HPLC separation of corpora cardiaca extracts gave several active fractions of which the most active was adipokinetic hormone 1 (AKH-1).     

Relationship of adipokinetic hormone I and II to migratory propensity in the grasshopper, Melanoplus sanguinipes

This report examines three aspects of adipokinetic hormone (AKH) involvement in migratory flight behavior in the grasshopper, Melanoplus sanguinipes. The titer of hemolymph AKH I during long-duration tethered flight was examined using radioimmunoassay (RIA) after narrow bore RP-HPLC. The hemolymph fraction containing AKH I was assayed using commercially available anti-Tyr1-AKH I serum. Titer determinations of hemolymph AKH were done at rest and after various periods of flight. The amount of AKH I released from the corpora cardiaca during flight was estimated. When resting levels of AKH I and II in corpora cardiaca (CC) of migrants and non-migrants were examined with HPLC, no significant differences in AKH levels were detected between non-migrants, animals that had flown for 1 h to identify them as migrants, and animals that had flown to exhaustion (i.e., voluntary cessation). CC levels of both AKH I and II were less in this species than in locusts. When the lipid mobilization in response to AKH I and II was compared in migrants (animals that had self-identified as migrants in a 1-h tethered flight test) and non-migrants (animals that would not perform a 1-h flight in a tethered flight test), the adipokinetic response to AKH I was greater in migrants than in non-migrants, possibly indicating differences in level of sensitivity or number of receptors in the target tissues. AKH II had little effect on hemolymph lipid levels in either flight group, and may not play a significant role in lipid mobilization in this species.     

The effect of photoperiod on the calling behaviour of virgin females of the true armyworm,Pseudaletia unipuncta (Haw.) (Lepidoptera: Noctuidae)

The effect of photoperiod on the calling behaviour of Pseudaletia unipuncta virgin females was examined under five different photoperiodic regimes at 25°C, 65% r.h. The age at which females called for the first time following emergence varied with photoperiod; generally calling was later under long-scotophase conditions. However under a 6 h scotophase there was also a delay in calling and >63% of the females tested never called. There was a considerable variability in the daily calling patterns between the different photoperiods, and the mean onset time of calling was not constant with either “lights on” or “light off”. There was however a constancy of the mean onset time of calling relative to the mid-point of both the photo- and scotophase at all photoperiods tested, indicating that females could measure the absolute duration of either the photo- or scotophase. Transferring females from one photoperiodic condition to another once calling had been initiated, determined that it was the “lights off” signal that P. unipuncta females used to phase set the clock governing circadian calling behaviour.Females subjected to a decrease of 4 or 6 h in the length of the scotophase following the initiation of calling required several days to adjust to the new photoperiodic regime and a high proportion of females did not call during the night following the transfer. A 4 or 6 h increase in the scotophase did not inhibit calling on the night following the transfer but females still required several days to adjust completely. However, females experiencing a 2 h increase or decrease in the duration of the scotophase were able to maintain normal calling behaviour. The results of these experiments are discussed in relation to the seasonal biology of the true armyworm and the hypothesis that this is a migrant species.     

Mobilization of lipid and carbohydrate reserves in the migratory grasshopper Melanoplus sanguinipes

Abstract. The North American migratory grasshopper Melanoplus sanguinipes Fabricius (Orthoptera: Acrididae) exhibits heritable variation in predisposition to make long-duration flights, and performance of long-duration flight enhances reproductive output. As a first step in understanding the physiological basis of these phenomena, we examined the mobilization of lipid and carbohydrate reserves during flight and in response to injection of extracts of the corpora cardiaca. Extract of conspecific corpora cardiaca elevates the concentration of haemolymph lipid. Both synthetic locust adipokinetic hormone I (AKH I) and synthetic Locusta migratoria AKH II raise the concentration of lipid in the haemolymph. However, although AKH I is more active than AKH II in locusts, dose-response curves for the two peptides are similar in M.sanguinipes. Neither extract of conspecific corpora cardiaca nor locust AKH I affects haemolymph carbohydrate in this species. Haemolymph carbohydrate and total glycogen reserves are Diminished by tethered flight; in contrast, haemolymph lipid is elevated by flight. Grasshoppers identified as presumptive migrants or non-migrants do not differ significantly in body composition. Total lipid reserves did not decrease measurably after extended flight, even though total reserves of carbohydrate do not appear to be sufficient to maintain the durations of flight performed.     

cDNA cloning and expression analysis of the juvenile hormone acid methyltransferase from seabuckthorn carpenterworm,Holcocerus hippophaecolus (Lepidoptera: Cossidae)

In this study, we report the cDNA cloning and sequence determination of Hh‐JHAMT from the seabuckthorn carpenterworm, Holcocerus hippophaecolus, by using rapid amplification of cDNA ends. The full‐length cDNA of putative Hh‐JHAMT was 1659 bp and contained a highly conserved Motif I, SAM motif I, which showed that Hh‐JHAMT like enzyme was a member of SAM‐dependent MTases. Moreover, putative Hh‐JHAMT had high homology to the other members of the JHAMT peptide family: 59% with Spodoptera litura, 54% with Bombyx mori and 54% with Helicoverpa armigera. Multiple alignments and phylogenetic analysis revealed that Hh‐JHAMT was closely related to JHAMT from Lepidoptera. Real‐time quantitative PCR experiments showed that Hh‐JHAMT mRNA expression was highest in the corpora allata (CA) complex, and was also detected at high levels during earlier larval and adult stages. The JHAMT mRNA level gradually declined during larval development, and the lowest amount of expression was observed in the pupal stage, while it increased to a higher level during adult stages. The pattern of Hh‐JHAMT expression was similar to the mode of JH biosynthesis. These results provided information concerning molecular characteristics of Hh‐JHAMT, whose expression profile suggests that the Hh‐JHAMT gene might be changed with larval development, metamorphosis and adult reproduction of the H. hippophaecolus.     

The combined effect of photoperiod and temperature on the calling behaviour of the true army worm, Pseudaletia unipuncta

ABSTRACT. Pseudaletia unipuncta (Haw.) (Lepidoptera: Noctuidae) virgin females, maintained at either 10 or 25d?C under LD 12:12 or 16:8 h, started calling at different ages. For a given photoperiod, calling was initiated 11 days later at 10d?C than at 25d?C, while for a given temperature, calling at LD 12:12 h was 3–4 days later than at LD 16:8 h. At 10d?C 50.8% of females did not call within 35 days at LD 12:12 h compared with 30.8% at LD 16:8 h. Calling started earlier in the scotophase at 10d?C than at 25d?C and at LD 16:8 h than at LD 12:12 h. Under all treatments calling generally advanced on successive nights. The time elapsed between the mean onset time of calling and the mid-scotophase was relatively constant under both photoperiod conditions at 25d?C, but at 10d?C was more variable. The mean time spent calling increased significantly with calling age but did not differ significantly between the four experimental conditions tested. Older (15 days) females transferred from 10d?C, LD 16:8 h to 25d?C at either LD 163 or 12:12 h, required less time to initiate calling than younger (5 days) ones. Those transferred from 10d?C, LD 12:12 h took the same time, regardless of their age at the time of the transfer. Females experiencing either a decrease or increase in daylength as well as a temperature increase, required respectively more or less time to initiate calling, compared with individuals that only experienced an increase in temperature. If temperature was the only parameter changed females that initiated calling soon after the transfer immediately adjusted their calling periodicity to prevailing conditions. When both temperature and photoperiod were altered, it took several days before calling periodicity adjusted to the new regime. The ecological implications of temperature and photoperiodic conditions on the possible autumn migration of P. unipuncta are discussed.     

The role of the frontal ganglion and corpora cardiaca/corpora allata complex in post-feeding weight loss in adult Heliothis zea

Abstract A post-feeding diuretic response has been observed in adult Heliothis zea (Boddie) (Lepidoptera: Noctuidae). 2-day-old starved adults which were allowed to feed to repletion on a 10% (w/v) sucrose solution lost 49.1% (females) and 85.8% (males) of the weight of the ingested meal during the first hour following feeding. Ligation between head and thorax or frontal ganglionectomy, when performed immediately following feeding, each resulted in a significant and permanent reduction in this normal weight-loss. Injection of homogenates of the corpora cardiaca/corpora allata (CC/CA) complex into non-ligated insects immediately after feeding also reduced significantly the post-feeding weight-loss, but this inhibition was transient and disappeared after 1 h. Dissection and weighing of the crop from either ligated, frontal ganglionectomized, or CC/CA-injected insects confirmed the crop as the predominant site of fluid retention in each case. We suggest that a soluble antidiuretic factor from the CC/CA acts in conjunction with the frontal ganglion to control the rate of crop emptying and subsequent diuresis by regulating the volume of ingested fluid that is passed into the haemolymph from the crop/midgut.     

Adipokinetic hormone enhances laminarin and bacterial lipopolysaccharide-induced activation of the prophenoloxidase cascade in the African migratory locust,Locusta migratoria

Lom-AKH-I enhances the activation in vivo of prophenoloxidase in the haemolymph of the African migratory locust, Locusta migratoria, in response to challenge with laminarin. AKH does not influence the speed or initial magnitude of the phenoloxidase response to laminarin, but prolongs the period of activation of the enzyme in a dose-dependent manner. Injections of preparations of bacterial lipopolysaccharide (LPS) do not activate prophenoloxidase in vivo, but co-injection of Lom-AKH-I with commercial preparations of LPS from Klebsiella pneumoniae, Escherichia coli, or Shigella flexneri (but not one from Pseudomonas aeroginosa) results in dose-dependent increases in the levels of phenoloxidase that persist in the haemolymph for several hours. It is argued that the effects of AKH on phenoloxidase activation in locusts described here are, at least in part, related directly to changes in lipid metabolism brought about by the hormone.     

Serological study on the transmission of a granulosis virus of the armyworm,Pseudaletia unipuncta (Lepidoptera: Noctuidae), to other lepidopterous species

The synergistic (Hawaiian) strain of a granulosis virus (GV) from the armyworm, Pseudaletia unipuncta, was transmitted to Spodoptera exigua, Autographa californica, and Trichoplusia ni. The viruses isolated from these hosts were tested by radial double-immunodiffusion (RDD) and immunoelectrophoresis (IE) for their relationship to the original virus. Untreated and heat-treated virus inclusion bodies (capsules) were compared for their antigenic properties but no differences were detected. The antiserum elicited against the whole capsule was more sharply specific for the antigenic determinants than the one elicited against the dissolved capsule proteins. The viruses obtained from S. exigua and T. ni elicited precipitin lines that differed from those of the P. unipuncta GV in their electrophoretic mobility with the one-trough IE method; however, with the two-trough method, the lines fused indicating that the antigens were identical. The major precipitin line indicating identity of the viruses wasthat produced by the synergistic factor (SF) purified from the capsule proteins of the synergistic GV strain. The presence of SF in the GV produced in alternate hosts indicated that its production was virus directed. The SF was not detected in the GVs of Laspeyresia pomonella and Pieris rapae and in the nonsynergistic Oregonian GV of P. unipuncta. A field-collected GV from S. exigua exhibited a different precipitin pattern from that of the synergistic GV, but one of the precipitin lines shared partial relationship to the SF.     

Hormonal control of hemolymph lipoprotein ice nucleators in overwintering freeze-susceptible larvae of the stag beetle Ceruchus piceus: adipokinetic hormone and juvenile hormone

Summary Freeze-resistant overwintering larvae of the stag beetle Ceruchus piceus do not produce antifreezes in winter, but instead lower their supercooling points by seasonal removal of lipoprotein ice nucleators (LPINs) from the hemolymph. The normal lipid transport function of these lipoproteins becomes less essential during winter because of the low temperatures and the diapause state of the larvae. Adipokinetic hormone (AKH) and juvenile hormone (JH) were shown to be involved in the control of supercooling abilities and LPIN levels. Treatment of midwinter larvae with AKH resulted in an increase in ice nucleator activity within 2 h, associated with elevated levels of LPINs, as demonstrated by Western blots derived from native PAGE gels probed with polyclonal antibodies to the LPINs. AKH also stimulated the release of LPIN in vitro from cultured fat bodies. In contrast, JH treatments of larvae with high hemolymph ice nucleator contents (either autumn or spring larvae) caused a decrease in ice nucleator activity and supercooling points. However, Western blots showed increased LPIN levels in these JH treated larvae. Apparently, this JH-induced, inactive form of LPIN lacks some component(s) essential for ice nucleator activity.Abbreviations AKH Adipokinetic hormone - Apo-I Apolipoprotein-I - Apo-II Apolipoprotein-II - JH Juvenile hormone - LPIN Lipoprotein ice nucleator - PAGE Polyacrylamide gel electrophoresis - SDS Sodium dodecyl sulfate - SCP Supercooling point - THP Thermal hysteresis protein - HDLp High density lipophorin - VHDLp Very high density lipophorin