Improved efficiency of Kiltz07-KEM

Kiltz proposed a practical key encapsulation mechanism(Kiltz07-KEM) which is secure against adaptive chosen ciphertext attacks(IND-CCA2) under the gap hashed Diffie-Hellman(GHDH) assumption\cite{Kiltz2007}. We show a variant of Kiltz07-KEM which is more efficient than Kiltz07-KEM in encryption. The new scheme can be proved to be IND-CCA2 secure under the same assumption, GHDH

Diel Feeding Rhythm and Grazing Selectivity of Small-Sized Copepods in a Subtropical Embayment, the Northern South China Sea

Small marine copepods are key components of the pelagic food webs in Chinese coastal waters, but very few studies have addressed their trophodynamics, with even fewer studies addressing their diel feeding rhythms. In this study, the diel feeding rhythm and grazing selectivity of the copepod assemblage in Daya Bay during September 30 to October 2, 2014, were studied based on gut pigment analysis. Small copepods (body length < 1.5 mm) including Paracalanus parvus, Temora turbinata, Acrocalanus gibber, Temora stylifera, Euterpe acutifrons, and Acrocalanus gracilis, accounted for 73.9–100% of the total copepod abundance. The copepod assemblage generally exhibited a diurnal feeding pattern, characterized by a higher gut pigment content and ingestion rate during the daytime, consistent with variation in the ambient Chl α concentration. Fifty-five percent of the phytoplankton standing stock per day was consumed by the copepod assemblage, wherein diatoms, prymnesiophytes, and cyanobacteria were the main prey items with average contributions of 19.4–32.9% to the gut pigment contents. The copepod assemblage showed a strong feeding preference for prymnesiophytes, a weak feeding preference for diatoms, and avoidance of cyanobacteria. These results suggest a strong top-down control on phytoplankton community, especially on small groups from small copepods in the Daya Bay ecosystem

Multi-omics analysis explores the effect of chronic exercise on liver metabolic reprogramming in mice

Background: The effect of exercise on human metabolism is obvious. However, the effect of chronic exercise on liver metabolism in mice is less well described.Methods: The healthy adult mice running for 6 weeks as exercise model and sedentary mice as control were used to perform transcriptomic, proteomic, acetyl-proteomics, and metabolomics analysis. In addition, correlation analysis between transcriptome and proteome, and proteome and metabolome was conducted as well.Results: In total, 88 mRNAs and 25 proteins were differentially regulated by chronic exercise. In particular, two proteins (Cyp4a10 and Cyp4a14) showed consistent trends (upregulated) at transcription and protein levels. KEGG enrichment analysis indicated that Cyp4a10 and Cyp4a14 are mainly involved in fatty acid degradation, retinol metabolism, arachidonic acid metabolism and PPAR signaling pathway. For acetyl-proteomics analysis, 185 differentially acetylated proteins and 207 differentially acetylated sites were identified. Then, 693 metabolites in positive mode and 537 metabolites in negative mode were identified, which were involved in metabolic pathways such as fatty acid metabolism, citrate cycle and glycolysis/gluconeogenesis.Conclusion: Based on the results of transcriptomic, proteomics, acetyl-proteomics and metabolomics analysis, chronic moderate intensity exercise has certain effects on liver metabolism and protein synthesis in mice. Chronic moderate intensity exercise may participate in liver energy metabolism by influencing the expression of Cyp4a14, Cyp4a10, arachidonic acid and acetyl coenzyme A and regulating fatty acid degradation, arachidonic acid metabolism, fatty acyl metabolism and subsequent acetylation

Folate-deficiency induced acyl-CoA synthetase short-chain family member 2 increases lysine crotonylome involved in neural tube defects

Maternal folate deficiency increases the risk of neural tube defects (NTDs), but the mechanism remains unclear. Here, we established a mouse model of NTDs via low folate diets combined with MTX-induced conditions. We found that a significant increase in butyrate acid was observed in mouse NTDs brains. In addition, aberrant key crotonyl-CoA-producing enzymes acyl-CoA synthetase short-chain family member 2 (ACSS2) levels and lysine crotonylation (Kcr) were elevated high in corresponding low folate content maternal serum samples from mouse NTD model. Next, proteomic analysis revealed that folate deficiency led to global proteomic modulation, especially in key crotonyl-CoA-producing enzymes, and dramatic ultrastructural changes in mouse embryonic stem cells (mESCs). Furthermore, we determined that folate deficiency induced ACSS2 and Kcr in mESCs. Surprisingly, folic acid supplementation restored level of ACSS2 and Kcr. We also investigated overall protein post-translational Kcr under folate deficiency, revealing the key regulation of Kcr in glycolysis/gluconeogenesis, and the citric acid cycle. Our findings suggest folate deficiency leads to the occurrence of NTDs by altering ACSS2. Protein crotonylation may be the molecular basis for NTDs remodeling by folate deficiency

Acetylome analyses provide novel insights into the effects of chronic intermittent hypoxia on hippocampus-dependent cognitive impairment

IntroductionChronic intermittent hypoxia (CIH) can negatively affect hippocampal function through various molecular mechanisms. Protein acetylation, a frequently occurring modification, plays crucial roles in synaptic plasticity and cognitive processes. However, the global protein acetylation induced by CIH in the hippocampus and its specific effects on hippocampal function and behavior remain poorly understood.MethodsTo address this gap, we conducted a study using liquid chromatography-tandem mass spectrometry to analyze the lysine acetylome and proteome of the hippocampus in healthy adult mice exposed to intermittent hypoxia for 4 weeks (as a CIH model) compared to normoxic mice (as a control).ResultsWe identified and quantified a total of 2,184 lysine acetylation sites in 1,007 proteins. Analysis of these acetylated proteins revealed disturbances primarily in oxidative phosphorylation, the tricarboxylic acid (TCA) cycle, and glycolysis, all of which are localized exclusively to mitochondria. Additionally, we observed significant changes in the abundance of 21 proteins, some of which are known to be associated with cognitive impairments.DiscussionThis study helps to elucidate the molecular mechanisms underlying CIH-induced changes in protein acetylation in the hippocampus. By providing valuable insights into the pathophysiological processes associated with CIH and their impacts on hippocampal function, our findings contribute to a better understanding of the consequences of CIH-induced changes in protein acetylation in the hippocampus and the potential role of CIH in cognitive impairment

Fate of carbon and phosphorus by the grazing of daphnia

The carbon (C) and phosphorus (P) kinetics were studied in Daphnia magna using 14C and 33P as radiotracers. The potential effects of food quantity, food quality (in terms of phosphorus content), life-stage, and algal species were tested. At food concentrations of 0.03-0.3 mg C 1-1 (C:P ratio=90 in molar), the C dietary assimilation efficiencies (AEs) were 34-70% and were independent of life-stages, while the P AEs were 38%-85% in the adults and 66-89% in the juveniles at food concentrations of 2-40 μg (C:P =90) P 1-1. A negative correlation was found between food concentration and C AE, while the P AE decreased exponentially with an increase in food concentration. The C AEs were comparable between two algal species Chlamydomonas reinhardtii and Scenedesmus obliquus. The P AE increased under low food quality (C: P ratio > 300). The C turnover rate was 0.12-0.16 d-1 and 0.32-0.35 d-1 in the juveniles and adults, while the P turnover rate was 0.096-0.185 d-1and 0.182-0.298 d-1in the juveniles and adults, respectively. The turnover rates of C and P were independent of food quantity, however, the P turnover rate decreased significantly under low food quality. C was lost through different compartments including respiration, excretion, molting, and reproduction from D. magna during the efflux period, among which DOC and reproduction were the most important. In contrast, molting was the most important route for P loss from the animals. Allocation of C loss but not P loss varied between the juveniles and adults. The relative allocations of C and P were independent of food quantity except for respiration or DP in adults. Under low food quality (C:P >300), the mass specific loss rates of P through all the compartments decreased. Stoichiometric regulation in D. magna under P-limitation was explored. With the increase of P-limitation, the C and P AEs and C turnover rate increased while the P turnover rate decreased significantly. The specific C loss rates from respiration, dissolved release, and molting all increased, while the specific P loss rates from all the responsible compartments decreased, strongly suggesting the overall stoichiometric regulation in D. magna. In comparison of the importance of inefficient feeding and post-ingestive process (excretion and feces leakage) of D. magna in contributing to DOC production, the role of direct excretion of animals was highlighted on DOC production in this study. The relative DOC production (DP/ingestion) was affected by both food quality and grazer density but not by algal species and food quantity. In conclusion, this study constructed the integrated carbon and phosphorus budgets and demonstrated the overall stoichiometric regulation of C and P budgets under P-limitation in Daphnia. Furthermore, this study revealed that DOC excretion by Daphnia may make a great contribution to the overall DOC production in a phytoplankton-herbivore system

Relative importance of inefficient feeding and consumer excretion to organic carbon flux from Daphnia

1. Sloppy and inefficient feeding by zooplankton is generally thought to make a major contribution to the regeneration of the dissolved organic carbon (DOC) pool in aquatic environments. In this study, we tested experimentally the regeneration of DOC by a freshwater zooplankter feeding on two species of phytoplankton at different food concentrations and C : P ratios. We separated the DOC production because of inefficient feeding (pre-ingestive regeneration) and zooplankton excretion and faeces release (postdigestive regeneration). 2. Within a brief incubation period (10 min), DOC production in the presence of Daphnia was not significantly different from that in the control treatment without grazers. During a longer incubation period (4 h), the amounts of radiocarbon retained in the algal cells per se were constant or were not different from those in the control treatments. These experimental results strongly suggest that inefficient feeding did not contribute significantly to DOC production in the grazer-prey system. 3. During the 4-h incubation, calculations of the DOC per ingestion rate (i.e. DOC produced by Daphnia alone) showed that food concentration and algal species did not affect the relative DOC production, but there was considerable difference at different algal C : P ratios and grazer densities. We found that direct excretion of DOC by Daphnia occurred rapidly following food digestion and accounted for > 65\% of the total DOC production. Maximum DOC leakage from Daphnia faeces contributed less to DOC production than the grazer excretion, except under P-limited conditions. 4. This study highlights the dominant role of postingestive process, especially the direct excretion by zooplankton, in DOC production in a grazer-prey system

Stoichiometric regulation of carbon and phosphorus in P-deficient Daphnia magna

Daphnia magna were fed phosphorus-sufficient (+P) and P-deficient (-P) green algae Chlamydomonas reinhardtii (carbon : phosphorus ratio of C: P 5 90 and 930 in molar, respectively) for 5 d to produce different body C: P ratios. The dietary absorption as well as the elimination of body C and P were then quantified under contrasting dietary qualities (+P and -P). The -P animals fed with -P algae had a higher absorption efficiency (AE) of both C (46\%) and P (52\%) than the control (+P animals fed +P algae) and the recovery group (-P animals fed +P food). During the physiological efflux, the -P animals fed with -P diet eliminated their body C at the highest rate (0.41 d(-1)) and their body P at the lowest rate (0.10 d(-1)) among the three groups of animals. Mass-specific C loss rates through dissolved release, respiration, and molting increased significantly, and the mass-specific P loss through dissolved release, molting, and reproduction decreased in the -P animals compared with the +P animals, in agreement with the stoichiometric models. Consequently, the C: P ratio of dissolved release, molting, and reproduction all increased with the increase in P deficiency. The recovered Daphnia had medium values of AE, efflux rate constant, and mass-specific loss rates, indicating the reversibility of P limitation. Our study demonstrated that all the pathways (excretion, reproduction, molting, and respiration) may be involved in the stoichiometric regulation in Daphnia

Kinetics of phosphorus in Daphnia at different food concentrations and carbon:phosphorus ratios

We examined the assimilation efficiency, excretion, and efflux of phosphorus (P) in adults and juveniles of Daphnia magna under different food levels (2-40 mu g P L-1) and dietary carbon: phosphorus (C: P) ratios (90-930 in molar) with Chlamydomonas reinhardtii as food. The P assimilation efficiencies calculated by regression analysis were 38-85\% and 66-89\% for adults and juveniles, respectively, and were constant at food concentrations > 24 mu g P L-1, but increased significantly when the diet shifted from P-sufficiency to P-deficiency. The mass-specific excretion rate of adults and juveniles was 1.1-33.2 ng P mg dry weight (DW)(-1) h(-1) and 3.0-63.4 ng P mg DW-1 h(-1), respectively, and was influenced by the food concentration and decreased with an increase in dietary C: P ratio. The efflux rate constants of the adults and juveniles were 0.182-0.298 d(-1) and 0.096-0.185 d(-1), respectively. Food concentration did not affect the efflux, but an increase in dietary C:P ratio reduced the P efflux, suggesting stoichiometric regulation. Among the different routes involved in P loss from Daphnia, molting was the most important, contributing 44-75\% of the total loss for the juveniles and adults. The mass specific loss rates were 13-54 ng P mg(-1) h(-1) and 45-110 ng P mg(-1) h(-1). The relative and absolute P loss from each compartment (except the dissolved P release in adults) was independent of food concentration. Increasing the dietary C:P ratio decreased the mass-specific release rates by molting, dissolved P release, and reproduction, indicating the animals' endeavor to maintain P stoichiometric homeostasis