Disruptive coloration and background pattern matching

Effective camouflage renders a target indistinguishable from irrelevant background objects. Two interrelated but logically distinct mechanisms for this are background pattern matching (crypsis) and disruptive coloration: in the former, the animal's colours are a random sample of the background; in the latter, bold contrasting colours on the animal's periphery break up its outline. The latter has long been proposed as an explanation for some apparently conspicuous coloration in animals, and is standard textbook material. Surprisingly, only one quantitative test of the theory exists, and one experimental test of its effectiveness against non-human predators. Here we test two key predictions: that patterns on the body's outline should be particularly effective in promoting concealment and that highly contrasting colours should enhance this disruptive effect. Artificial moth-like targets were exposed to bird predation in the field, with the experimental colour patterns on the 'wings' and a dead mealworm as the edible 'body'. Survival analysis supported the predictions, indicating that disruptive coloration is an effective means of camouflage, above and beyond background pattern matching.

Mimicry of ice structure by surface hydroxyls and water of a beta-helix antifreeze protein

Insect antifreeze proteins (AFP) are much more effective than fish AFPs at depressing solution freezing points by ice-growth inhibition. AFP from the beetle Tenebrio molitor is a small protein (8.4 kDa) composed of tandem 12-residue repeats (TCTxSxxCxxAx). Here we report its 1.4-A resolution crystal structure, showing that this repetitive sequence translates into an exceptionally regular beta-helix. Not only are the 12-amino-acid loops almost identical in the backbone, but also the conserved side chains are positioned in essentially identical orientations, making this AFP perhaps the most regular protein structure yet observed. The protein has almost no hydrophobic core but is stabilized by numerous disulphide and hydrogen bonds. On the conserved side of the protein, threonine-cysteine-threonine motifs are arrayed to form a flat beta-sheet, the putative ice-binding surface. The threonine side chains have exactly the same rotameric conformation and the spacing between OH groups is a near-perfect match to the ice lattice. Together with tightly bound co-planar external water, three ranks of oxygen atoms form a two-dimensional array, mimicking an ice section.

Biodegradation of Polyethylene and Plastic Mixtures in Mealworms (Larvae of Tenebrio molitor) and Effects on the Gut Microbiome

Recent studies have demonstrated the ability for polystyrene (PS) degradation within the gut of mealworms ( Tenebrio molitor). To determine whether plastics may be broadly susceptible to biodegradation within mealworms, we evaluated the fate of polyethylene (PE) and mixtures (PE + PS). We find that PE biodegrades at comparable rates to PS. Mass balances indicate conversion of up 49.0 ± 1.4% of the ingested PE into a putative gas fraction (CO₂). The molecular weights ( M_n) of egested polymer residues decreased by 40.1 ± 8.5% in PE-fed mealworms and by 12.8 ± 3.1% in PS-fed mealworms. NMR and FTIR analyses revealed chemical modifications consistent with degradation and partial oxidation of the polymer. Mixtures likewise degraded. Our results are consistent with a nonspecific degradation mechanism. Analysis of the gut microbiome by next-generation sequencing revealed two OTUs ( Citrobacter sp. and Kosakonia sp.) strongly associated with both PE and PS as well as OTUs unique to each plastic. Our results suggest that adaptability of the mealworm gut microbiome enables degradation of chemically dissimilar plastics.

Pore canals and related structures in insect cuticle

The fine structure and the distribution of an esterase have been studied in the cuticle of Galleria larvae, Tenebrio larvae and pupae, and in the wax-secreting cuticle of the honey bee, and compared with those in the cuticle of the caterpillar of Calpodes. In Galleria and Tenebrio the pore canals are spaces passing through the lamellate endocuticle from the epithelium to the epicuticle. They contain a filament from the cells which may be concerned in their formation. The shape of the pore canal is probably determined by the orientation of the fibres making up the lamellae in the endocuticle and is not a regular helix. The pore canals also contain numerous filaments of another sort which pass on through the epicuticle and are believed to be the origin of the surface wax. They are particularly abundant in the pore canals of the honey bee wax-secreting cuticle and extend into the cell in long pockets surrounded by an envelope of the plasma membrane. The esterase is probably concerned with the final stage of wax synthesis, for its distribution is similar to that of the lipid filaments.

Echolocation signals reflect niche differentiation in five sympatric congeneric bat species

Echolocating bats can be divided into guilds according to their preferred habitat and foraging behaviour, which coincide with distinct adaptations in wing morphology and structure of echolocation signals. Although coarse structuring of niche space between different guilds is generally accepted, it is not clear how niches differ within guilds, or whether there is fine-grained niche differentiation reflected in echolocation signal structure. Using a standardized performance test, here we show clutter-dependent differences in prey-capture success for bats from five species of European Myotis. These species are morphologically similar, sympatric, and all belong to the guild labelled "edge space aerial/trawling foragers". We further demonstrate a strong correlation between the prey-detection ability of the species and the respective search-call bandwidth. Our findings indicate that differences in echolocation signals contribute to within-guild niche differentiation. This is the first study relating sensory abilities of a set of potentially competing animal species to a direct measure of their respective foraging performance, suggesting an important role of sensory ecology in the structuring of animal communities.

Biodegradation of Polystyrene by Dark ( Tenebrio obscurus) and Yellow ( Tenebrio molitor) Mealworms (Coleoptera: Tenebrionidae)

Yellow mealworms (larvae of Tenebrio molitor, Coleoptera: Tenebrionidae) have been proven to be capable of biodegrading polystyrene (PS) products. Using four geographic sources, we found that dark mealworms (larvae of Tenebrio obscurus) ate PS as well. We subsequently tested T. obscurus from Shandong, China for PS degradation capability. Our results demonstrated the ability for PS degradation within the gut of T. obscurus at greater rates than T. molitor. With expanded PS foam as the sole diet, the specific PS consumption rates for T. obscurus and T. molitor at similar sizes (2.0 cm, 62-64 mg per larva) were 32.44 ± 0.51 and 24.30 ± 1.34 mg 100 larvae^-1 d^-1, respectively. After 31 days, the molecular weight ( M_n) of residual PS in frass (excrement) of T. obscurus decreased by 26.03%, remarkably higher than that of T. molitor (11.67%). Fourier transform infrared spectroscopy (FTIR) indicated formation of functional groups of intermediates and chemical modification. Thermo gravimetric analysis (TGA) suggested that T. obscurus larvae degraded PS effectively based on the proportion of PS residue. Co-fed corn flour to T. obscurus and wheat bran to T. molitor increased total PS consumption by 11.6% and 15.2%, respectively. Antibiotic gentamicin almost completely inhibited PS depolymerization. High-throughput sequencing revealed significant shifts in the gut microbial community in both Tenebrio species that were associated with the PS diet and PS biodegradation, with changes in three predominant families (Enterobacteriaceae, Spiroplasmataceae, and Enterococcaceae). The results indicate that PS biodegradability may be ubiquitous within the Tenebrio genus which could provide a bioresource for plastic waste biodegradation.

Insecticidal properties of several monoterpenoids to the house fly (Diptera: Muscidae), red flour beetle (Coleoptera: Tenebrionidae), and southern corn rootworm (Coleoptera: Chrysomelidae)

House flies, Musca domestica (L.), and their eggs were treated with 22 monoterpenoids to determine the topical, fumigant, and ovicidal activity of each compound. Fumigant activity of 14 monoterpenoids were examined further using red flour beetles, Tribolium castaneum (Herbst). Third-instar southern corn rootworm, Diabrotica undecimpunctata howardi Barber, were treated with carvacrol, citral, citronellal, menthol, pulegone, verbenol, and verbenone to determine their activity on larvae. Structure-activity relationships were evaluated with the toxicity data. We made comparisons between monocyclic aromatic, acyclic aliphatic, monocyclic aliphatic, and bicyclic aliphatic alcohols, ketones, aldehydes, and acids to determine toxicity differences involving the skeletal structure, amount of saturation, and associated functional groups of monoterapenoids. Ketones were more effective than alcohols in the topical, fumigant (T. castaneum), and ovicidal bioassays and less toxic than an analogous aldehyde in the topical, fumigant (M. domestica), and ovicidal bioassays. Aldehydes were more toxic than alcohols in the topical and fumigant (M. domestica) bioassays. In the topical and ovicidal bioassays, aromatic or acyclic alcohols, or both, were more effective than monocyclic and bicyclic alcohols. Vapors of bicyclic ketones were more toxic than monocyclic ketones to adult M. domestica. Monoterpenoid alcohols containing three carbon-carbon double bonds were more effective than saturated alcohols in the topical and larval bioassays. A mono-unsaturated ketone was more toxic than a structurally similar saturated ketone and two di-unsaturated ketones when it was applied topically to adult M. domestica. A saturated monocyclic ketone inhibited egg hatch more effectively than unsaturated monocyclic ketones.

Biodegradation of Polyvinyl Chloride (PVC) in Tenebrio molitor (Coleoptera: Tenebrionidae) larvae

Tenebrio molitor larvae (Coleoptera: Tenebrionidae) are capable of depolymerizing and biodegrading polystyrene and polyethylene. We tested for biodegradation of Polyvinyl Chloride (PVC) in T. molitor larvae using rigid PVC microplastic powders (MPs) (70-150 μm) with weight-, number-, and size-average molecular weights (M_w, M_n and M_z) of 143,800, 82,200 and 244,900 Da, respectively, as sole diet at 25 °C. The ingestion rate was 36.62 ± 6.79 mg MPs 100 larvae^-1 d^-1 during a 16-day period. The egested frass contained about 34.6% of residual PVC polymer, and chlorinated organic carbons. Gel permeation chromatography (GPC) analysis indicated a decrease in the M_w, M_n and M_z by 33.4%, 32.8%, and 36.4%, respectively, demonstrating broad depolymerization. Biodegradation and oxidation of the PVC MPs was supported by the formation of OC and OC functional groups using frontier transform infrared spectroscopy (FTIR) and ¹H nuclear magnetic resonance (¹H NMR), and by significant changes in the thermal characteristics using thermo-gravimetric analysis (TGA). Chloride released was counted as about 2.9% of the PVC ingested, indicating limited mineralization of the PVC MPs. T. molitor larvae survived with PVC as sole diet at up to 80% over 5 weeks but did not complete their life cycle with a low survival rate of 39% in three months. With PVC plus co-diet wheat bran (1:5, w/w), they completed growth and pupation as same as bran only in 91 days. Suppression of gut microbes with the antibiotic gentamicin severely inhibited PVC depolymerization, indicating that the PVC depolymerization/biodegradation was gut microbe-dependent. Significant population shifts and clustering in the gut microbiome and unique OTUs were observed after PVC MPs consumption. The results indicated that T. molitor larvae are capable of performing broad depolymerization/biodegradation but limited mineralization of PVC MPs.

Thermodynamic stability of a cold-active alpha-amylase from the Antarctic bacterium Alteromonas haloplanctis

The thermal stability of the cold-active alpha-amylase (AHA) secreted by the Antarctic bacterium Alteromonas haloplanctis has been investigated by intrinsic fluorescence, circular dichroism, and differential scanning calorimetry. It was found that this heat-labile enzyme is the largest known multidomain protein exhibiting a reversible two-state unfolding, as demonstrated by the recovery of DeltaHcal values after consecutive calorimetric transitions, a DeltaHcal/DeltaHeff ratio close to unity, and the independence of unfolding thermodynamic parameters of scan rates. By contrast, the mesophilic alpha-amylases investigated here (from porcine pancreas, human salivary glands, yellow meal beetle, Bacillus amyloliquefaciens, and Bacillus licheniformis) unfold irreversibly according to a non-two-state mechanism. Unlike mesophilic alpha-amylases, the melting point of AHA is independent of calcium and chloride binding while the allosteric and structural functions of these ions are conserved. The thermostability of AHA at optimal conditions is characterized by a Tm of 43.7 degrees C, a DeltaHcal of 238 kcal mol-1, and a DeltaCp of 8.47 kcal mol-1 K-1. These values were used to calculate the Gibbs free energy of unfolding over a wide range of temperatures. This stability curve shows that (a) the specific DeltaGmax of AHA [22 cal (mol of residue)-1] is 4 times lower than that of mesophilic alpha-amylases, (b) group hydration plays a crucial role in the enzyme flexibility at low temperatures, (c) the temperature of cold unfolding closely corresponds to the lower limit of bacterial growth, and (d) the recombinant heat-labile enzyme can be expressed in mesophilic hosts at moderate temperatures. It is also argued that the cold-active alpha-amylase has evolved toward the lowest possible conformational stability of its native state.

Biodegradation of polypropylene by yellow mealworms (Tenebrio molitor) and superworms (Zophobas atratus) via gut-microbe-dependent depolymerization

Polypropylene (PP), a fossil-based polyolefin plastics widely used worldwide, is non-hydrolyzable and resistant to biodegradation as a major source of plastic pollutants in environment. This study focused on feasibility of PP biodegradation in the larvae of two species of darkling beetles (Coleoptera: Tenebrionidae) i.e., yellow mealworms (Tenebrio molitor) and superworms (Zophobas atratus) using PP foam with number-, weight-, and size-average molecular weights (M_n, M_w, and M_z) of 109.8, 356.2, and 765.0 kDa, respectively. The tests were conducted in duplicates with respective larvae (300 T. molitor and 200 Z. atratus each incubator) at 25 °C and 65% humidity for over a 35-day period. The larvae of T. molitor and Z. atratus fed with PP foam as sole diet consumed PP at 1.0 ± 0.4 and 3.1 ± 0.4 mg 100 larvae^-1 days^-1, respectively; when fed the PP foam plus wheat bran, the consumption rates were enhanced by 68.11% and 39.70%, respectively. Gel permeation chromatography analyses of the frass of T. molitor and Z. atratus larvae fed PP only indicated that M_w was decreased by 20.4 ± 0.8% and 9.0 ± 0.4%; M_n was increased by 12.1 ± 0.4% and 61.5 ± 2.5%; M_z was decreased by 33.8 ± 1.5% and 32.0 ± 1.1%, indicating limited extent depolymerization. Oxidation and biodegradation of PP was confirmed through analysis of the residual PP in frass. Depression of gut microbes with the antibiotic gentamicin inhibited PP depolymerization in both T. molitor and Z. atratus larvae. High throughput 16S rRNA sequencing revealed that Citrobacter sp. and Enterobacter sp. were associated with PP diets in the gut microbiome of Z. atratus larvae while Kluyvera was predominant in the T. molitor larvae. The results indicated that PP can be biodegraded in both T. molitor and Z. atratus larvae via gut microbe-dependent depolymerization with diversified microbiomes.

Functional significance of loops in the receptor binding domain of Bacillus thuringiensis CryIIIA delta-endotoxin

Analysis of the three surface loops in domain II of Bacillus thuringiensis CryIIIA delta-endotoxin has been carried out to assess their role in receptor binding and toxicity. Site-directed mutagenesis was used to convert loop residues to alanine and the mutant proteins were analyzed for structural stability, toxicity to beetle larvae (Tenebrio molitor), binding to receptors on T. molitor brush border membrane vesicles (Tm-BBMV) and insertion into BBMV, as measured by irreversible membrane receptor binding. This study demonstrates the functional significance of loops for binding and insertion. Alanine replacements in loop I resulted in disruption of receptor binding or structural instability. The double mutation, Y350A, Y351A, could be suppressed by replacing a nearby R345 with alanine, and the resultant mutant protein also showed reduced receptor binding. Substitution of N353 and D354 in loop I with alanine residues caused the loss of binding ability and toxicity. A loop II double mutant, P412A, S413A, had no effect on binding or toxicity. A block mutation of loop III residues to alanine had the effect of reducing receptor binding while concomitantly increasing toxicity by 2.4-fold. We compared this up-mutant to wild-type toxin in each step of physiological processing of protoxin: solubility, proteolytic activation, and insertion into the Tm-BBMV. The loop III block mutant showed increased membrane insertion, but was similar to wild-type toxin in other parameters. These results reveal that loop I and loop III in domain II of CryIIIA delta-endotoxin are involved in receptor binding. In addition, the direct correlation between toxicity and irreversible binding of the loop III block mutant (despite the indirect relationship to reversible binding) suggests that loop III may play a role in membrane insertion.

Predators' Toxin Burdens Influence Their Strategic Decisions to Eat Toxic Prey

Toxic prey advertise their unprofitability to predators via conspicuous aposematic coloration [1]. It is widely accepted that avoidance learning by naive predators is fundamental in generating selection for aposematism [2, 3] and mimicry [4, 5] (where species share the same aposematic coloration), and consequently this cognitive process underpins current evolutionary theory [5, 6]. However, this is an oversimplistic view of predator cognition and decision making. We show that predators that have learned to avoid chemically defended prey continue to attack defended individuals at levels determined by their current toxin burden. European starlings learned to discriminate between sequentially presented defended and undefended mealworms with different color signals. Once birds had learned to avoid the defended prey at a stable asymptotic level, we experimentally increased their toxin burdens, which reduced the number of defended prey that they ingested in the subsequent trial. This was due to the birds making strategic decisions to ingest defended prey on the basis of their visual signals. Birds are clearly able to learn about the nutritional benefits and defensive costs of eating defended prey, and they regulate their intake according to their current physiological state. This raises new perspectives on the evolution of aposematism, mimicry, and defense chemistry.

Uricotelism and low evaporative water loss in a South American frog

A South American anuran (Phyllomedusa sauvagii) produced large amounts of semisolid urate when it was maintained on a diet of insects. Rates of evaporative water loss in Phyllomedusa sauvagii were only about 5 to 10 percent of those other anurans tested and were similar to those of lizards of comparable size.

Structural basis for the inhibition of mammalian and insect alpha-amylases by plant protein inhibitors

Alpha-amylases are ubiquitous proteins which play an important role in the carbohydrate metabolism of microorganisms, animals and plants. Living organisms use protein inhibitors as a major tool to regulate the glycolytic activity of alpha-amylases. Most of the inhibitors for which three-dimensional (3-D) structures are available are directed against mammalian and insect alpha-amylases, interacting with the active sites in a substrate-like manner. In this review, we discuss the detailed inhibitory mechanism of these enzymes in light of the recent determination of the 3-D structures of pig pancreatic, human pancreatic, and yellow mealworm alpha-amylases in complex with plant protein inhibitors. In most cases, the mechanism of inhibition occurs through the direct blockage of the active center at several subsites of the enzyme. Inhibitors exhibiting "dual" activity against mammalian and insect alpha-amylases establish contacts of the same type in alternative ways.

Potassium activation and K spikes in muscle fibers of the mealworm Iarva (Tenebrio molitor)

Muscle fibers of larval mealworms ( Tenebrio molitor) can be set to a wide range of resting potentials (ca. –40 to –90 mv), while remaining responsive to electrical stimuli. The initial resting potential is maintained long after K+0 is increased to levels well above the normal value (ca. 40 mEq/liter). However, spikes or graded responses are markedly affected by the level of K+0. For levels between 40 and 150 mEq/liter the terminal portion of the responses may become prolonged depolarizations, and for K+0 above about 200 mEq/liter positive overshoots occur. These changes follow the Nernst relation for K+0 > 20 mEq/liter. Thus, the membrane of the muscle fiber at rest is not a K electrode, but changes to the latter state during a response, indicating occurrence of K activation. The "K spikes" which develop in high K+0 lack an early depolarizing component, which is comparable to that subsumed under the Na activation and inactivation processes of the Hodgkin-Huxley theory. The K spikes may last for many seconds and are associated with increased membrane conductance throughout this time. The K spikes are probably terminated by a process of depolarizing K inactivation.

Response of the yellow mealworm (Tenebrio molitor) gut microbiome to diet shifts during polystyrene and polyethylene biodegradation

Plastic biodegradation by mealworm is regarded as an emerging strategy for plastic disposal. In this study, the polystyrene (PS) and low density polyethylene (LDPE) degradation efficiency by yellow mealworms (Tenebrio molitor larvae) supplemented with bran and the effects of plastics on the gut core microbiome were explored to construct a circular and continuous reactor for plastic biodegradation in the future. The gut microbiome was also investigated with dietary shift to explore the relationship between specific diets and gut microbes. The bran plus plastic (7:1 ratio, w/w) co-diet contributed to the mealworm survival and growth. The formation of -C˭O-/-C-O- groups in the plastic-fed mealworms frass represented the oxidation process of plastic biodegradation in the mealworm gut. The changes in molecular weights (M_w, M_n and M_z) of residual PS and LDPE in mealworms frass compared with that of PS and PE feedstock confirmed the plastic depolymerization and biodegradation. Lactobacillus and Mucispirillum were significantly associated with PE + bran diet compared to bran diet and PE diet, representing the response of mealworm gut microbiome to the bran and plastic mixture was distinguished from either bran or plastics alone. The gut microbiome changed substantially with the diet shift, indicating that microbial community assembly was a stochastic process and diverse plastic-degrading bacteria might occur in the mealworm gut.

Growth performance, blood profiles and carcass traits of Barbary partridge (Alectoris barbara) fed two different insect larvae meals (Tenebrio molitor and Hermetia illucens)

To investigate the effect of two insect meals (from Hermetia illucens, HI and Tenebrio molitor, TM larvae) on productive performance and blood profiles of Barbary partridge, ninety, seven days old partridges were divided into 5 groups (6 replicates, 3 partridges/replicate). Up to 64d, the groups fed 5 isoproteic and isoenergetic diets: the control fed a corn-soybean meal diet (SBM group); in TM25 and TM50 groups the 25 and 50% of SBM proteins were substituted by the protein from TM, respectively; in HI25 and HI50 groups the 25 and 50% of SBM were substituted by the protein from HI, respectively. The birds fed TM25 and both the HI levels reached a higher (P<0.01) live weight at 64d than the control. Considering the entire experimental period the TM groups had a more favorable FCR than SBM. The carcass weights of all the insect groups were higher (P<0.01) than the control. The weight of the full digestive tract in SBM group was the highest (P<0.01). The caecal weight, the intestinal and caecal length were the highest (P<0.01) in the SBM group. The SBM group the highest value of albumin/globulin (P<0.01) and creatinine (P<0.05). TM seems to be more effective than HI in improving FCR. The reduced albumin/globulin ratio in the insect meal fed groups could be ascribed to the chitin content and this result was not affected by the amount of chitin intake, suggesting that also the lowest values are able to express their potential effects in partridges.

Biodegradation of polylactic acid by yellow mealworms (larvae of Tenebrio molitor) via resource recovery: A sustainable approach for waste management

Polylactic acid (PLA) is biodegraded rapidly under composting or thermophilic temperature but slowly under natural conditions with substantial microplastics generated. In this study, we examined the feasibility of PLA biodegradation and developed a novel approach for PLA waste management using yellow mealworms (Tenebrio molitor larvae) to achieve biodegradation and resource recovery simultaneously. Results confirmed PLA biodegradation in mealworms as sole PLA and PLA-bran mixtures (10%, 20%, 30% and 50% PLA, wt/wt). Feeding PLA-bran mixtures supported the larval development with higher survival rates and lower cannibal rates than feeding PLA only at ambient temperature. The PLA conversion efficiency was 90.9% with 100% PLA diet and was around 81.5-86.9% with PLA-bran mixtures. A peak insect biomass yield was achieved at a PLA ratio of 20%. PLA biodegradation was verified via detection of chemical and thermal modifications. Gut microbial community analysis indicated that intestinal communities shifted with PLA biodegradation, resulting in clusters with OTUs unique to the PLA diet. Based on these findings, we propose a circular approach for PLA waste management via resource recovery of used PLA as the feedstock for insect biomass production, management of mealworm excrement waste as fertilizer, and utilization of agricultural products for PLA production.

Identification of the ice-binding face of antifreeze protein from Tenebrio molitor

The beetle Tenebrio molitor produces several isoforms of a highly disulfide-bonded beta-helical antifreeze protein with one surface comprised of an array of Thr residues that putatively interacts with ice. In order to use mutagenesis to identify the ice-binding face, we have selected an isoform that folds well and is tolerant of amino acid substitution, and have developed a heating test to monitor refolding. Three different types of steric mutations made to the putative ice-binding face reduced thermal hysteresis activity substantially while a steric mutation on an orthogonal surface had little effect. NMR spectra indicated that all mutations affected protein folding to a similar degree and demonstrated that most of the protein folded well. The large reductions in activity associated with steric mutations in the Thr array strongly suggest that this face of the protein is responsible for ice binding.

Tenebrio molitor Larvae Inhibit Adipogenesis through AMPK and MAPKs Signaling in 3T3-L1 Adipocytes and Obesity in High-Fat Diet-Induced Obese Mice

Despite the increasing interest in insect-based bioactive products, the biological activities of these products are rarely studied adequately. Larvae of Tenebrio molitor, the yellow mealworm, have been eaten as a traditional food and provide many health benefits. Therefore, we hypothesized that T. molitor larvae might influence adipogenesis and obesity-related disorders. In the present study, we investigated the anti-adipogenic and antiobesity effects of T. molitor larvae in vitro and in vivo. The lipid accumulation and triglyceride content in mature adipocytes was reduced significantly (up to 90%) upon exposure to an ethanol extract of T. molitor larvae, without a reduction in cell viability. Exposure also resulted in key adipogenic and lipogenic transcription factors. Additionally, in adipogenic differentiation medium the extract induced phosphorylation of adenosine monophosphate (AMP)-activated protein kinase and mitogen-activated protein kinases. Daily oral administration of T. molitor larvae powder to obese mice fed high-fat diet attenuated body weight gain. We also found that the powder efficiently reduced hepatic steatosis as well as aspartate and alanine transaminase enzyme levels in mice fed a high-fat diet. Our results suggest that T. molitor larvae extract has an antiobesity effect when administered as a food supplement and has potential as a therapeutic agent for obesity.

Stabilization of supercooled fluids by thermal hysteresis proteins

It has been reported that thermal hysteresis proteins found in many cold-hardy, freeze-avoiding arthropods stabilize their supercooled body fluids. We give evidence that fish antifreeze proteins, which also produce thermal hysteresis, bind to and reduce the efficiency of heterogenous nucleation sites, rather than binding to embryonic ice nuclei. We discuss both possible mechanisms for stabilization of supercooled body fluids and also describe a new method for measuring and defining the supercooling point of small volumes of liquid.