Lipid Mass Research Articles

Condition states in anchovy (Engraulis encrasicolus) and sardine (Sardina pilchardus) revealed by energy and proximate composition relationships.

Energy content has long been proposed as a fundamental, integrated, and reliable indicator of the condition of individuals as it reflects past bioenergetics and influences future life-history traits. There is a direct biochemical link between energy density and body composition described by four main compounds in fish (protein, lipid, ash, and water), with proteins and lipids being the sources of energy. If relationships between water content, or lipid content, and energy density have been well described in relative terms, the absolute mass variations in the proximate composition have been overlooked and thus their interpretation is often equivocal. In our study, based on a large and unique dataset on the proximate composition and energy density of anchovy (Engraulis encrasicolus) and sardine (Sardina pilchardus) from sampling in the Bay of Biscay and the English Channel, we aimed to better explain the patterns between water content and other proximate components or energy density, based on the dynamics of proteins, lipids, and water absolute masses. For the first time, we defined good, intermediate, and poor condition states in wild fish, based on water content, corresponding to the different dynamics of lipids and proteins in the metabolism of individuals. Anchovy and sardine exhibited remarkably similar patterns of variation in the compounds and in the limits between the condition states with respect to water content. Those patterns revealed that water mass remained constant for a given fish size whatever its condition state, and that variability in water content only resulted from the variation in lipid and protein masses. Furthermore, the differential dynamics of proteins and lipids, with only lipids mobilized in the good condition state, only proteins in the poor condition state, and both proteins and lipids in the intermediate condition state, elucidates the nonlinear pattern observed in the relationship between energy density and water content. Overall, our results highlight the importance of monitoring the intraspecific variations in water content to predict the proximate composition and energy content in small pelagic fish and better assess individual and population conditions in changing ecosystems as well as to better parameterize bioenergetic models.

Effects of fasting on golden pompano Trachinotus ovatus: Physiological and biochemical responses

In practice, golden pompano (Trachinotus ovatus) reared in offshore cages may experience short-term fasting during extreme weather conditions, yet their physiological and biochemical responses remain poorly understood. To investigate the responses of this species to fasting, golden pompano weighing 138.0 ± 2.1 g were deprived of food for 0, 7, 14, 21 and 28 days, followed by assessments of body mass, somatic parameters, proximate composition, muscle glycogen, intestinal digestive enzymes, muscle amino acid and fatty acid profiles, nutritional value, and muscle texture and water holding capacity. Lower condition factor, hepatosomatic index, viscerosomatic index, hepatic glycogen, and intestinal activities of amylase, lipase and trypsin were found in the fasted fish than in the non-fasted fish, while a sharp decline in these parameters occurred on the first week of fasting. Fresh mass, dry mass, whole body and muscle contents of crude protein and lipid tended to decrease with prolonged fasting, while no statistical differences were found in these parameters between fish fasted for 7 days and the non-fasted fish. Furthermore, the decline rate of whole body crude lipid was consistently higher than that of whole body crude protein throughout the different stages of the 28-day fasting period, with the exception of the second week of fasting. No statistical differences were found in the total essential amino acids (∑EAA), non-essential amino acids (∑NEAA), ratio of ∑EAA to∑NEAA, chemical score, amino acid score, and essential amino acid index in the fasted fish compared to the non-fasted fish of group 0d. Fasting altered the muscle profile of SFA, MUFA and PUFA, sometimes reducing muscle springiness (groups 7d and 14d) and hardness (group 21d). Compared to non-fasted fish, fish fasted for 7 and 14 days exhibited statistically lower or equal drip loss, water loss rate, storage losses, and frozen exudate rate, whereas higher cooked meat rate. The above results indicate that during the 28-day fasting period, the visceral fat and hepatic glycogen are initially metabolized, followed by body proteins and lipids, to maintain the normal metabolism in fasted fish. Fasting has beneficial effects on the nutritional value of amino acids and fatty acids in muscle, although it modifies the muscle SFA, MUFA and PUFA composition and sometimes has negative effects on muscle texture. Considering the balance between body weight loss and flesh quality improvement, the duration of fasting for cultured golden pompano prior to harvesting should not exceed 14 days.

237 Increasing the threonine-to-lysine ratio improves the growth performance of slow-growing pigs when fed with precision feeding techniques

Abstract Individual precision feeding (IPF) is a suitable tool to account for the nutritional requirement variability among pigs. It was previously reported that, within IPF, pigs require greater Thr:Lys than conventional group-phase feeding (GPF) pigs. It remains unknown if these differences in Thr:Lys requirements occur due to different growth rates (Gr). This study evaluated whether the Thr:Lys requirements of pigs fed with IPF systems are affected by Gr. Sixty pigs (30 barrows and 30 gilts) with 38.1 ± 3.8 kg of body weight were distributed in a completely randomized 3 × 5 factorial arrangement. Pigs were classified into fast (FGr), medium (MGr) and slow (SGr) Gr based on their average daily gain (ADG) during 6 wk previous to the trial. After classification, pens with 2 barrows and 2 gilts from the same Gr group were randomly assigned to one of five treatments (12 repetitions per treatment). Treatments consisted of a conventional GPF (GPF100) receiving 100% of the optimal 0.65 Thr:Lys and 4 IPF treatments providing 140% (IPF140), 120% (IPF120), 100% (IPF100) and 80% (IPF80) of the optimal ratio. GPF100 pigs were fed a single diet with 0.97% standardized ileal digestible Lys. IPF diets of the pigs were adjusted every 2 d to meet the Lys requirements of the most demanding pig in the pen. Body weight was recorded twice a week, and individual feed intake (ADFI) daily over 21 d. At d 1 and 21, pigs were scanned with dual X-ray to estimate their body composition. Body weight, body protein and lipid masses were analyzed as repeated measures over time. The Dunnett test was used to compare the IPF treatments to GPF100 and the Tukey test to compare Gr groups. The pig was considered the experimental unit. FGr maintained greater (treatment × Gr, P < 0.05) ADFI and ADG and greater (P < 0.05) lipid deposition over the trial when compared with MGr and SGr. However, increasing Thr:Lys enhanced (P < 0.05) ADG and ADFI of SGr pigs within IPF, resulting in similar (P > 0.05) values between Gr groups in IPF120 and IPF140. Although FGr tended (P = 0.05) to have greater final body protein mass, SGr presented leaner gain (P < 0.05), independently of the Thr:Lys. Threonine supplementation supports metabolic processes like glycine and serine synthesis, impacting gut health, protein synthesis, energy production, and oxidative stress, potentially explaining lower lipid deposition in SGr pigs when the same level of energy in the diet. SGr pigs might need a different AA profile where a higher Thr:Lys ratio likely enhances the metabolic capacity to support fast growth in SGr pigs within IPF. Consequently, increasing the Thr:Lys ratio within IPF led to improved growth performance in SGr pigs.

Mechanisms and Factors Influencing the Production of Uniform-Sized Giant Unilamellar Vesicles by Discrete Lipid Film Arrays.

In this paper, we innovatively proposed a highly uniform vesicle preparation scheme based on the intervesicle mechanical self-constraint effect of vesicle crowding. By adjusting the spacing of discrete microwell structures, we observed that during the self-assembly of phospholipid molecules in microwells to form giant unilamellar vesicles (GUVs), the scale swelling of the vesicles during the continuous growth process would lead to the crowding of vesicles in adjacent microwells, thus inducing the formation of intervesicle mechanical self-constraint effect. The results of the experiment showed that this paper obtained the optimized discretized microwell structure (micropillar side: 30 μm; pitch: 0 μm), and the corresponding lipid mass was measured and determined, yielding homogeneous giant GUVs of 37.9 ± 2.0 μm. In this paper, homogenized GUVs (∼40 μm) with different cholesterol concentrations (10, 20, and 30%) were obtained by this method, and the above vesicles were subjected to controlled electroporation experiment under external electric fields of 23, 31, and 41 kV/cm, respectively. It showed that the mechanical self-constraint effect of vesicle crowding induced by patterned microstructures during the self-assembly of phospholipid molecules significantly enhances the size homogeneity of GUVs, which would be helpful for the wide applications of GUVs in other areas such as cell-like models and controlled release of drugs.

Fresh Carrier for an Old Topical Local Anesthetic: Benzocaine in Nanostructured Lipid Carriers.

Nanostructured lipid carriers (NLC) have emerged as innovative drug delivery systems, offering distinct advantages over other lipid-based carriers, such as liposomes and solid lipid nanoparticles. Benzocaine (BZC), the oldest topical local anesthetic in use, undergoes metabolism by pseudocholinesterase, leading to the formation of p-aminobenzoic acid, a causative agent for allergic reactions associated with prolonged BZC usage. In order to mitigate adverse effects and enhance bioavailability, BZC was encapsulated within NLC. Utilizing a 23 factorial design, formulations comprising cetyl palmitate (solid lipid), propylene glycol monocaprylate (liquid lipid), and Pluronic F68 as surfactants were systematically prepared, with variations in the solid/liquid lipid mass ratios (60:40-80:20%), total lipid contents (15-25%), and BZC concentrations (1-3%). The optimized formulation underwent characterization by dynamic light scattering, differential scanning calorimetry, Raman imaging, X-ray diffraction, small-angle neutron scattering, nanotracking analysis, and transmission electron microscopy (TEM)/cryo-TEM, providing insights into the nanoparticle structure and the incorporation of BZC into its lipid matrix. NLCBZC exhibited a noteworthy encapsulation efficiency (%EE = 96%) and a 1 year stability when stored at 25 °C. In vitro kinetic studies and in vivo antinociceptive tests conducted in mice revealed that NLCBZC effectively sustained drug release for over 20 h and prolonged the anesthetic effect of BZC for up to 18 h. We therefore propose the use of NLCBZC to diminish the effective anesthetic concentration of benzocaine (from 20 to 3% or less), thus minimizing allergic reactions that follow the topical administration of this anesthetic and, potentially, paving the way for new routes of BZC administration in pain management.

Persistent and Bioaccumulative Halogenated Natural Products in Various Tropical Reef Fish Species from the Seychelles, Western Indian Ocean.

Gas chromatography with electron capture negative ion mass spectrometry (GC/ECNI-MS) was used to quantify and compare halogenated natural products (HNPs) and selected anthropogenic persistent organic pollutants (POPs) in individual samples of 17 fish species from the Seychelles (Western Indian Ocean). The sum-HNP amounts (9.5-1100 ng/g lipid mass (lm)) were between 1 and 2 orders of magnitude higher than those of the sum of seven abundant polychlorinated biphenyl (PCB) congeners (0.2-15 ng/g lm) and dichlorodiphenyltrichloroethane-related compounds (DDTs) (<1.1-43 ng/g lm). Within the group of HNPs, the two tetrabrominated phenoxyanisoles (aka methoxylated diphenyl ethers, MeO-BDEs), 2'-MeO-BDE 68 ≫ 6-MeO-BDE 47, were predominant in most cases. Pearson correlation analysis showed that MeO-BDE levels were positively correlated with less abundant HNPs (2,2'-diMeO-BB 80, 2',6-diMeO-BDE 68, and Br6-DBP) (p < 0.01). Accordingly, HNPs, rather than PCBs and DDTs, were the predominant polyhalogenated contaminants in the current species.

Pitfalls in lipid mass spectrometry of mammalian samples - a brief guide for biologists.

Pitfalls in lipid mass spectrometry of mammalian samples - a brief guide for biologists.

A trade-off between desiccation resistance and developmental humidity for pupation height in the North Indian seasonal population of Drosophilid-Zaprionus indianus

Drosophila larvae and pupae are vulnerable to seasonal abiotic stressors such as humidity and temperature. In wild low-humidity habitats, desiccation stress can occur as Drosophila larvae forsake wet food in search of a drier pupation site. Henceforth, the hypothesis that developmental humidity impacts pupation height, affecting larval and pupae water balance and fitness-related traits, was examined. Accordingly, warm-adapted Drosophilid- Zaprionus indianus from two seasons were reared under season-specific simulated conditions, with significantly varying relative humidity (summer RH: 40%; rainy RH: 80%), but nearly identical temperatures. A trade-off between pupation height and developmental humidity was observed. Drier summer conditions lead to pupae wandering farther from drier glass surfaces, resulting in higher pupation height (17.3 cm) while rainy pupae prefer wet food, resulting in lower pupation height (7.12 cm). Additionally, density-dependent pupation height was developmental humidity-specific, with most rainy-season pupae pupated on wetter food, while dry summer pupae pupated on glass surfaces or cotton. Nevertheless, flies from far pupation exhibited greater desiccation resistance, fecundity, and copulation duration than those from near pupation. The cuticular lipid mass of larvae and pupae was higher during far-than-near pupation, indicating decreased water loss rates compared to near-pupation. Finally, pupae eclosion (%) was unaffected by greater humidity (85%) in either season. Still, it considerably decreased at lower humidity (RH: 0% and 38%) for rainy pupae, further supporting the selection of low-humidity desiccation resistance in pupae. In conclusion, low humidity is crucial for survival of pre-adult stages of Zaprionus indianus under desiccation stress and for preference of pupation site.

Association between Life’s Essential 8 and cataract among US adults

Currently, a comprehensive assessment of the relationship between ideal cardiovascular health (CVH) indicators and cataract risk is lacking. Life’s Essential 8 (LE8) is the latest concept proposed by the American Heart Association to comprehensively reflect CVH status. LE8 includes four health behaviors (diet, physical activity, smoking, and sleep) and four health factors (blood lipid, blood sugar, blood pressure, and body mass index). This study tried to evaluate the association between LE8 and cataract using data from National Health and Nutrition Examination Survey (NHANES) 2005–2008, a continuous research program which aims to monitor and evaluate the health and nutrition status of the US population. A cross-sectional study of 2720 non-cataract participants and 602 cataract participants. All participants were assigned to the poor, intermediate, and ideal CVH status groups based on LE8 score. Weighted multiple logistic regression was used to investigate the correlation between the LE8 score and cataract, as well as the correlation between each of the eight subitems and cataract, with potential confounding variables being adjusted. Then, restricted cubic spline analysis was used to further explore whether there was a nonlinear relationship between LE8 score and cataract. The proportion of cataract participants was 14.1%, 18.2%, and 20.6% in the ideal, intermediate, and poor CVH groups, respectively (P < 0.05). LE8 score was inversely associated with cataract risk, with each 10-point increase in LE8 score associated with a 14% reduction in cataract risk [odds ratio (OR) = 0.86, 95% confidence interval (CI): 0.79–0.93, P < 0.01]. Among all the LE8 subitems, physical activity, sleep, and blood glucose were significantly associated with cataract risk (all P < 0.05). Better CVH, defined by a higher LE8 score, is associated with a lower cataract risk. Efforts to improve LE8 score (especially when it comes to physical activity, sleep, and blood glucose) may serve as a novel strategy to help reduce the risk of cataract.

Lipidomics and transcriptomics analysis revealed the role of the spleen of Nile tilapia (Oreochromis niloticus) in lipid metabolism

In fish, the development of the spleen is not as perfect as that of higher vertebrates, but it has the same functions that the spleen should have. Up to date, research on fish spleen is mostly focused on its immune function, and the roles and mechanisms of spleen in the regulation of fish metabolism are still unclear. For this purpose, we established a spleen-deficient model of Nile tilapia (Oreochromis niloticus) by splenectomy and integrated lipidomics and transcriptomics to study the changes and mechanisms of lipid metabolism in splenectomy tilapia so as to understand the effect of spleen on lipid metabolism in tilapia. We found that splenectomy can lead to lipid deposition in the liver of tilapia, significant changes in liver and serum lipid mass spectrometry, abnormal lipid metabolism, decreased anti-oxidative stress ability, and being more prone to lipid toxicity and fatty liver. Combined with the results of transcriptomics, we found that splenectomy resulted in down-regulation of differentially expressed genes in “cellular iron ion homeostasis,” “extracellular region,” “small molecule binding,” and “TGF-beta signaling pathway,” and iron metabolism-related genes such as tfa, bmp2b, bmp6, hamp, and slc40a1, etc. were closely related to differential lipid changes. Therefore, it is speculated that the abnormal lipid metabolism in tilapia after splenectomy is closely related to iron metabolism, and its molecular mechanism may be related to the hepcidin regulatory pathway—BMP-SMAD signaling pathway. This study can provide a new understanding of the relationship and mechanism between immune and nutritional metabolism in fish and also provide new ideas for the study of fish hepatic diseases.

Skeletal muscle PGC-1α remodels mitochondrial phospholipidome but does not alter energy efficiency for ATP synthesis.

Exercise training is thought to improve the mitochondrial energy efficiency of skeletal muscle. Some studies suggest exercise training increases the efficiency for ATP synthesis by oxidative phosphorylation (OXPHOS), but the molecular mechanisms are unclear. We have previously shown that exercise remodels the lipid composition of mitochondrial membranes, and some of these changes could contribute to improved OXPHOS efficiency (ATP produced by O2 consumed or P/O). Peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) is a transcriptional co-activator that coordinately regulates exercise-induced adaptations including mitochondria. We hypothesized that increased PGC-1α activity is sufficient to remodel mitochondrial membrane lipids and promote energy efficiency. Mice with skeletal muscle-specific overexpression of PGC-1α (MCK-PGC-1α) and their wildtype littermates were used for this study. Lipid mass spectrometry and quantitative PCR were used to assess muscle mitochondrial lipid composition and their biosynthesis pathway. The abundance of OXPHOS enzymes was determined by western blot assay. High-resolution respirometry and fluorometry analysis were used to characterize mitochondrial bioenergetics (ATP production, O2 consumption, and P/O) for permeabilized fibers and isolated mitochondria. Lipidomic analyses of skeletal muscle mitochondria from wildtype and MCK-PGC-1α mice revealed that PGC-1α increases the concentrations of cone-shaped lipids such as phosphatidylethanolamine (PE), cardiolipin (CL), and lysophospholipids, while decreases the concentrations of phosphatidylcholine (PC), phosphatidylinositol (PI) and phosphatidic acid (PA). However, while PGC-1α overexpression increased the abundance of OXPHOS enzymes in skeletal muscle and the rate of O2 consumption (JO2), P/O values were unaffected with PGC-1α in permeabilized fibers or isolated mitochondria. Collectively, overexpression of PGC-1α promotes the biosynthesis of mitochondrial PE and CL but neither PGC-1α nor the mitochondrial membrane lipid remodeling induced in MCK-PGC-1α mice is sufficient to increase the efficiency for mitochondrial ATP synthesis. These findings suggest that exercise training may increase OXPHOS efficiency by a PGC-1α-independent mechanism, and question the hypothesis that mitochondrial lipids directly affect OXPHOS enzymes to improve efficiency for ATP synthesis.

Abstract PO4-08-01: Methylsterol monooxygenase 1 (MSMO1) modulates endoplasmic reticulum stress through cholesterol metabolic reprogramming to alter chemotherapy sensitivity in breast cancer

Abstract Background Endoplasmic reticulum stress (ER stress) is a process in which cells activate unfolded protein response and other signaling pathways in response to misfolded and unfolded protein aggregation and calcium ion balance disturbance in the endoplasmic reticulum cavity. Depending on the intensity of endoplasmic reticulum stress, it can not only induce chaperone expression to play a protective effect, but also induce apoptosis independently. Metabolic reprogramming is one of the characteristics of tumor, which refers to the metabolic changes that cells make in response to various stimuli. Here, we demonstrate that methylsterol monooxygenase 1 (MSMO1) regulates cellular cholesterol metabolism and influences breast cancer susceptibility to chemotherapy by regulating the relative intracellular T-MAS content. Methods RNA-seq was performed on core needle biopsy samples from 26 patients receiving neoadjuvant chemotherapy for breast cancer to screen for genes that may influence neoadjuvant chemotherapy sensitivity. Cell proliferation, CCK8 assay and apoptosis assay were performed for MSMO1 phenotype study. Transmission electron microscopy (TEM) was conducted to visualize the structure of endoplasmic reticulum. Western Blot was used to detect the activation level of the unfolded protein response pathway. The relative content of sterols in MSMO1 knockdown cells was detected by targeted lipid mass spectrometry. AO/PI staining of breast cancer organoids was performed to verify the effect of MSMO1 metabolic substrate T-MAS on chemotherapy drug sensitivity. Results RNA-seq of core needle biopsy samples from breast cancer patients receiving neoadjuvant chemotherapy suggested that MSMO1 was highly expressed in non-pCR patients, and clinical survival data suggested that MSMO1 was associated with poor prognosis in patients with all types of breast cancer, suggesting that MSMO1 might be related to chemotherapy sensitivity of breast cancer. Phenotypic experiments revealed that MSMO1 regulates chemotherapy sensitivity of breast cancer both in vivo and in vitro. Ectopic overexpression of MSMO1 promoted cancer cell resistance to chemotherapy. To uncover the underlying mechanisms, RNA-seq of MSMO1 knock-down cells were carried out and identified that MSMO1 was associated with ER stress. TEM and western blot assay indicated that downregulation of MSMO1 expression leads to endoplasmic reticulum swelling and activation of the unfolded protein response. Considering that MSMO1 is a cholesterol metabolizing enzyme, targeted lipids mass spectrometry was performed to detect the changes in the contents of various intermediate metabolites in the cholesterol pathway, which indicated that the relative content of T-MAS, a metabolic substrate of MSMO1, was significantly up-regulated in MSMO1 knockdown cells. Then, in order to verify whether this metabolite can independently regulate ER stress, breast cancer cells were given T-MAS externally, and TEM and Western Blot analysis indicated that T-MAS could induce ER stress and activate the unfolded protein response independently. Apoptosis assay and AO/PI staining of breast cancer organoids revealed that T-MAS can improve the sensitivity of breast cancer to chemotherapy drugs. Conclusion In summary, these results shed light on the role of MSMO1 in cholesterol metabolism reprogramming, which adjust the endoplasmic reticulum stress state of cells by changing the relative content of intracellular T-MAS, and thereby influencing the sensitivity of breast cancer chemotherapy. As an intermediate metabolite of cholesterol metabolism, T-MAS has potential clinical application value of chemotherapy sensitization. Citation Format: Hengyu Ren, Liren Wangxu, Yayun Chi, Jiong Wu. Methylsterol monooxygenase 1 (MSMO1) modulates endoplasmic reticulum stress through cholesterol metabolic reprogramming to alter chemotherapy sensitivity in breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-08-01.

Low Hepatic Cardiolipin Levels Promote Increased Mitochondrial Electron Leak and Metabolic Dysfunction-associated Steatohepatitis

Mitochondria adapt to changing energetic demands of the cell. We recently reported that mitochondrial membrane lipid composition represents a regulatory mechanism by which effciency of oxidative phosphorylation becomes altered. Metabolic-associated fatty liver disease (MAFLD) is a progressive disorder characterized by oxidative stress and accumulation of fat in hepatocytes that can lead to metabolic dysfunction-associated steatohepatitis (MASH). We hypothesized that MAFLD alters mitochondrial membrane lipids to induce mitochondrial electron transfer ineffciency and promotes oxidative stress. Lipid mass spectrometric analyses in four models of MAFLD (high-fat diet, ob/ob, carbon tetrachloride administration (CCI4), and Gubra-Amylin-NASH® diet), revealed that low mitochondrial cardiolipin (CL) is a common signature associated with all MAFLD models. In hepa1-6 cells, lentivirus-mediated knockdown of cardiolipin synthase (CLS, generates CL in mitochondria) was suffcient to reduce respiration and increase electron leak. Liver mitochondria from mice with a hepatocyte-specific knockout of CLS exhibited defects in mitochondrial bioenergetics including increased electron leak, concomitant to pathogenesis of MASH. Together, these findings provide evidence that a reduction in hepatic cardiolipin may drive the progression of MAFLD to induce MASH pathology. R01GM144613-03R01AG074535-02S2R01DK107397 07. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Ontogenesis of honey bees (Apis mellifera) under the influence of temperature stress

The productivity of bee colonies mostly depends on the influence of exogenous factors. The most significant ones include: the presence of a honey base, climatic conditions, environmental temperature, etc. The stability of microclimate indicators in the nest significantly affect the growth of families and nest. The vital temperature range in the post-embryonic period ranges from 30–38 °С. For normal brood development, the incubation temperature should be 34–35 °С. The intensity of growth during this period is largely determined by the influence of climatic conditions, including temperature. As a result of decrease in temperature, there is a densification of the placement of bees, which are more concentrated in the central, breeding part of the nest. Under these conditions, hypothermia of individual areas of the brood, located on the peripheral parts of the honeycombs, beyond the healthy temperature range, is sometimes noted. This is manifested by a sharp drop in the ambient temperature, when there is a numerous brood in the family, or if the nest is not expanded properly. In order to study the influence of cold stress on the development of offspring, two groups were formed. The group incubated at a temperature of 35 ºС was considered the control group. The experimental group was a group which was grown at a temperature of 32 ºС. After the brood was sealed, pupae were selected every 2 days. At the same time, their mass, the content of total lipids and the ratio of their individual classes were determined. It was found that under the influence of cold stress during brood development, the duration of the incubation period increases by 35–42 hours. It has been established that the adaptation of bees to cold includes a complex of physiological and biochemical processes, among which changes in the mass and composition of lipids play a significant role. The dynamics of triacylglycerides under optimal and stressful conditions of incubation were studied. Taking into account their functional purpose as the main element of energy supply of metabolic pathways, such dynamics indicate profound changes in the processes of energy exchange. When studying the mechanisms of adaptation to cold, a change in the ratio of phospholipid classes, the expression of which is induced by the effect of cold, was revealed. The results of this study bring a deeper understanding of the adaptation mechanisms of honeybees' response to changes in brood incubation temperature. They expand data on the biology of bees during critical periods of growth and development.

Three-dimensional imaging to estimate in vivo body and carcass chemical composition of growing beef-on-dairy crossbred bulls

The dynamics of cattle body chemical composition during growth and fattening periods determine animal performance and beef carcass quality. The aim of this study was to estimate the empty body (EB) and carcass chemical composition of growing beef-on-dairy crossbred bulls (Brown Swiss breed as dam with Angus, Limousin or Simmental as sire) using three-dimensional (3D) imaging. The 3D images of the cattle’s external body shape were recorded in vivo on 48 bulls along growth trajectory (75–520 kg BW and 34–306 kg hot carcass weight [HCW]; set 1) and on 70 bulls at target market slaughter weight, including 18 animals from set 1 (average 517 ± 10 kg BW and 289 ± 10 kg HCW; set 2). The linear, circumference, curve, surface and volume measurements on the 3D body shape were determined. Those predictive variables were used in partial least square regressions, together with the effect of the sire breed whenever significant (P < 0.05), with leave-one-out cross-validation to estimate water, lipid, protein, mineral and energy mass or proportions in the EB and carcass. Mass and proportions were determined directly from postmortem grinding and chemical analyses (set 1) or indirectly using the 11th rib dissection method (set 2). In set 1, bulls’ BW and HCW were estimated via 3D imaging, with root mean square error of prediction (RMSEP) of 12 kg and 6 kg, respectively. The EB and carcass chemical component proportions were estimated with RMSEP from 0.2% for EB minerals (observed mean 3.7 ± 0.2%) to 1.8% for EB lipid (11.6 ± 4.2%), close to the RMSEP found for the carcass. In set 2, the RMSEP for estimation via 3D imaging was 9 kg for BW and 6 kg for HCW. The EB energy and protein proportions were estimated, with RMSEP of 0.5 MJ/kg fresh matter (10.1 ± 0.8 MJ/DM) and 0.2% (18.7 ± 0.7%), respectively. Overall, the estimations of chemical component proportions from 3D imaging were slightly less precise for both sets than the mass estimations. The morphological traits from the 3D images appeared to be precise estimators of BW, HCW as well as EB and carcass chemical component masses and proportions.

Effects of microRNA-305 knockdown on brain gene expression associated with division of labor in honey bee colonies (Apis mellifera).

Division of labor in honey bee colonies is based on the behavioral maturation of adult workers that involves a transition from working in the hive to foraging. This behavioral maturation is associated with distinct task-related transcriptomic profiles in the brain and abdominal fat body that are related to multiple regulatory factors including juvenile hormone (JH) and queen mandibular pheromone (QMP). A prominent physiological feature associated with behavioral maturation is a loss of abdominal lipid mass as bees transition to foraging. We used transcriptomic and physiological analyses to study whether microRNAs (miRNAs) are involved in the regulation of division of labor. We first identified two miRNAs that showed patterns of expression associated with behavioral maturation, ame-miR-305-5p and ame-miR-375-3p. We then downregulated the expression of these two miRNAs with sequence-specific antagomirs. Neither ame-miR-305-5p nor ame-miR-375-3p knockdown in the abdomen affected abdominal lipid mass on their own. Similarly, knockdown of ame-miR-305-5p in combination with JH or QMP also did not affect lipid mass. By contrast, ame-miR-305-5p knockdown in the abdomen caused substantial changes in gene expression in the brain. Brain gene expression changes included genes encoding transcription factors previously implicated in behavioral maturation. The results of these functional genomic experiments extend previous correlative associations of microRNAs with honey bee division of labor and point to specific roles for ame-miR-305-5p.

A fast-acting lipid checkpoint in G1 prevents mitotic defects

Lipid synthesis increases during the cell cycle to ensure sufficient membrane mass, but how insufficient synthesis restricts cell-cycle entry is not understood. Here, we identify a lipid checkpoint in G1 phase of the mammalian cell cycle by using live single-cell imaging, lipidome, and transcriptome analysis of a non-transformed cell. We show that synthesis of fatty acids in G1 not only increases lipid mass but extensively shifts the lipid composition to unsaturated phospholipids and neutral lipids. Strikingly, acute lowering of lipid synthesis rapidly activates the PERK/ATF4 endoplasmic reticulum (ER) stress pathway that blocks cell-cycle entry by increasing p21 levels, decreasing Cyclin D levels, and suppressing Retinoblastoma protein phosphorylation. Together, our study identifies a rapid anticipatory ER lipid checkpoint in G1 that prevents cells from starting the cell cycle as long as lipid synthesis is low, thereby preventing mitotic defects, which are triggered by low lipid synthesis much later in mitosis.

Population-specific responses to developmental temperature in the arboviral vector Aedes albopictus: Implications for climate change.

The increase of environmental temperature due to current global warming is not only favouring the expansion of the distribution range of many insect species, but it is also changing their phenology. Insect phenology is tightly linked to developmental timing, which is regulated by environmental temperatures. However, the degree to which the effects of developmental temperatures extend across developmental stages and their inter-stage relationships have not been thoroughly quantified in mosquitoes. Here, we used the mosquito Aedes albopictus, which is an aggressive invasive species and an arboviral vector, to study how developmental temperature influences fitness across developmental stages, thermal traits, energy reserves, transcriptome and Wolbachia prevalence in laboratory-reared populations originally collected from either temperate or tropical regions. We show that hatchability, larval and pupal viability and developmental speed are strongly influenced by temperature, and these effects extend to wing length, body mass, longevity and content of water, protein and lipids in adults in a population-specific manner. On the contrary, neither adult thermal preference nor heat resistance significantly change with temperature. Wolbachia density was generally lower in adult mosquitoes reared at 18°C than at other tested temperatures, and transcriptome analysis showed enrichment for functions linked to stress responses (i.e. cuticle proteins and chitin, cytochrome p450 and heat shock proteins) in mosquitoes reared at both 18 and 32°C. Our data showed an overall reduced vector fitness performance when mosquitoes were reared at 32°C, and the absence of isomorphy in the relationship between developmental stages and temperature in the laboratory population deriving from larvae collected in northern Italy. Altogether, these results have important implications for reliable model projections of the invasion potentials of Ae. albopictus and its epidemiological impact.

Effects of landscape metrics on scorpion (Arachnida: Scorpiones) assemblage in a tropical urban ecosystem.

Urban landscapes restrain the distribution of forest-dwelling species, which may be related to challenging conditions that impair body condition. The dynamics in urban areas lead to the simplification of communities that inhabit forest patches in cities with the turnover of sensitive species for opportunistic ones. In this study, we investigated the effect of urbanization on the body condition and diversity of scorpions at the landscape scale. Sampling was carried out in 10 forest patches in an urban matrix in Brazil, originally covered by a tropical rainforest. The surroundings of the landscape of each forest patch were characterized through the amount of forest, agriculture, and urban land cover. Individual body length, dry, lipid, and muscular masses were used as proxies of Tityus pusillus body condition. In total, 147 scorpions were collected, belonging to the species Ananteris mauryi, T. pusillus, T. stigmurus, and T. neglectus. Forest cover explained 28% of species variation. There was a positive relationship between forest cover and T. pusillus and A. mauryi abundances, while T. stigmurus was negatively affected by forest cover. Species richness and total scorpion abundance were not influenced by landscape metrics. In terms of body condition, only females of T. pusillus were affected by landscape variables, with individuals showing higher body mass with an increase in forest cover. Our results suggest that urban forests can support scorpion assemblages. However, there is a turnover in specialist forest species for opportunistic species. Forest cover is a crucial factor in maintaining healthy scorpion populations in urban areas.

Loss of PA28γ exacerbates imbalanced differentiation of bone marrow stromal cells during bone formation and bone healing in mice.

Proteasome activator subunit 3 (PA28γ) is a member of the proteasome activator family, which mainly regulates the degradation and stability of proteins. Studies have shown that it plays crucial roles in lipid formation, stemness maintenance, and blood vessel formation. However, few studies have clarified the association between PA28γ and bone diseases. Herein, we identified PA28γ as a previously unknown regulator of bone homeostasis that coordinates bone formation and lipid accumulation. PA28γ-knockout mice presented with the characteristics of low bone mass and accumulation of lipids. Suppressed expression of PA28γ restrained the osteogenic differentiation and enhanced the adipogenic differentiation of bone marrow stromal cells (BMSCs). Overexpression of PA28γ promoted osteogenic differentiation and inhibited adipogenic differentiation of BMSCs. Mechanistically, PA28γ interacted with Wnt5α, and the two interactors appeared to be positively correlated. PA28γ mainly activated the downstream Wnt/β-catenin signaling pathway, which affects BMSCs differentiation homeostasis. Deletion of Wnt5α significantly delayed the promotion of osteogenic differentiation and partially alleviated the inhibitory effect of adipogenic differentiation of BMSCs in the PA28γ-overexpressing group. Furthermore, we demonstrated that PA28γ-knockout mice had an inhibited rate of bone healing in a drill-hole femoral bone defect model in vivo. Therefore, our results confirm the effects of PA28γ on bone formation and bone defect repair, indicating that PA28γ mainly interacts with Wnt5α to activate the Wnt/β-catenin signaling pathway regulating BMSCs differentiation homeostasis. Our results reveal the function of PA28γ in bone diseases and provide a new theoretical basis for expanding the treatment of bone diseases.