Asymmetric Synthesis of Chiral 1,2-Bis(Boronic) Esters Featuring Acyclic, Non-Adjacent 1,3-Stereocenters.

The construction of acyclic, non-adjacent 1,3-stereogenic centers, prevalent motifs in drugs and bioactive molecules, has been a long-standing synthetic challenge due to acyclic nucleophiles being distant from the chiral environment. In this study, we successfully synthesized highly valuable 1,2-bis(boronic) esters featuring acyclic and nonadjacent 1,3-stereocenters. Notably, this reaction selectively produces migratory coupling products rather than alternative deborylative allylation or direct allylation byproducts. This approach introduces a new activation mode for selective transformations of gem-diborylmethane in asymmetric catalysis. Additionally, we found that other gem-diborylalkanes, previously challenging due to steric hindrance, also successfully participated in this reaction. The incorporation of 1,2-bis(boryl)alkenes facilitated the diversification of the alkenyl and two boron moieties in our target compounds, thereby enabling access to a broad array of versatile molecules. DFT calculations were performed to elucidate the reaction mechanism and shed light on the factors responsible for the observed excellent enantioselectivity and diastereoselectivity. These were determined to arise from ligand-substrate steric repulsions in the syn-addition transition state.

A Visible-Light-Induced Dynamic Mechanical Bond as a Linkage for Dynamic Materials.

Exploring dynamic bonds and their applications in fabricating dynamic materials has received great attention. A photoinduced [2]rotaxane-based dynamic mechanical bond (DMB) features visible-light-triggered dynamic bonding behavior that is essentially distinguished from conventional dynamic chemical bonds. In this DMB, a photoisomerizable ortho-fluoroazobenzene unit is introduced as a steric-controllable stopper, the visible-light-induced dynamic wagging movement of which enables the photoregulated threading of the macrocycle. This allows reversible in situ de-/reforming of the mechanical bond without involving dynamic chemical linkage. The DMB-cross-linked polymeric gel shows interesting photoinduced degradation behavior upon visible light irradiation. Benefiting from the distinctive dual dynamic nature of reversible bonding behavior and mechanical interlocked structure, this DMB is expected to serve as a new type of dynamic bond that can be applied in designing dynamic soft materials.

[Effects of light intensity on growth, survival, metabolism and related enzyme activities of Sepia pharaonis.] / å ‰ç §å¼ºåº¦å¯¹è™Žæ–‘ä¹Œè´¼ç”Ÿé•¿ã€å­˜æ´»ã€ä»£è°¢åŠç›¸å ³é ¶æ´»æ€§çš„å½±å“.

An experiment with single-factor design was conducted to investigate the effects of light intensity on growth and survival of cuttlefish (Sepia pharaonis). The specific growth rate, survival rate, oxygen consumption rate, ammonia excretion rate, lactic acid content in muscle, respiratory metabolic enzymes (including hexokinase, pyruvate kinase, and lactate dehydrogenase), supero-xide dismutase, and malondialdehyde in liver were measured in five constant light intensity treatments (10, 30, 50, 70, 90 µmol·m-2·s-1). The main results were as follows: The specific growth rate and survival rate remained steady initially and then decreased gradually with the increases of light intensity. There was no significant difference between groups 10 and 30 µmol·m-2·s-1, but they were significantly higher than those of the other groups. Exposed to light intensities of 10 and 30 µmol·m-2·s-1, the specific growth rates were (8.43±0.22)%·d-1 and (8.47±0.17)%·d-1, and the survival rates were (79.2±5.9)% and (80.0±4.9)%, respectively. Oxygen consumption rates and ammonia excretion rates increased first slowly and then sharply, and reached the maximum value when light intensity was 90 µmol·m-2·s-1, which was significantly higher than those of the other groups. Lactic acid content in muscle firstly decreased and then increased, with the minimum value at 30 µmol·m-2·s-1. The acid content of 10 µmol·m-2·s-1 was significantly lower than those of the other groups except 30 and 50 µmol·m-2·s-1. With the increases of light intensity, the activities of HK and PK in gills remained steady initially and then decreased gradually, and reached the highest level when exposed to 10 and 30 µmol·m-2·s-1, which were significantly higher than those of the other groups. LDH activity in muscle had the lowest level at the light intensity of 10 and 30 µmol·m-2·s-1, which was significantly lower than those of the other groups. SOD activity in liver firstly increased and then decreased, and reached the highest level ((104.93±4.17) U·mg-1 pro) when exposed to 70 µmol·m-2·s-1, which was significantly higher than those of the other groups. MDA content in liver first remained steady and then increased gradually, and reached the highest level ((5.06±0.35) nmol·mg-1 pro) when exposed to 90 µmol·m-2·s-1, which was significantly higher than those of the other groups. In conclusion, the optimum light intensities for growth, survival and metabolism of S. pharaonis were 10 and 30 µmol·m-2·s-1, beyond which S. pharaonis would be under stress. Therefore, sunproof measures should be taken to keep weak light condition in culture practice.

[Effects of light intensity and photoperiod on the embryonic development of Sepia pharaonis.] / å ‰ç §å¼ºåº¦ä¸Žå ‰å‘¨æœŸå¯¹è™Žæ–‘ä¹Œè´¼èƒšèƒŽå‘è‚²çš„å½±å“.

We investigated the effects of lumination on hatching of fertilized eggs of Sepia pharaonis, to reveal the best light conditions for its embryonic development. A single-factor experiment was carried out to examine the effects of different light intensities (10, 30, 50, 70, 90 µmol·m-2·s-1) and different photoperiod L:D (24 h:0 h, 18 h:6 h, 12 h:12 h, 6 h:18 h, 0 h:24 h) on the embryonic development. The results showed that the effects of light intensity on the hatching rate, fractured yolk sac rate, incubation period, mass of newly hatched larvae and mantle length was significant. There was no significant effect on hatching period and survival rate after hatching 7 days. With the increases of light intensity, the hatching rate, incubation period, mass of newly hatched larvae and mantle length first increased and then decreased, while the fractured yolk sac rate gradually increased. The optimum light intensity was 30 µmol·m-2·s-1. Exposed to this light intensity, the hatching rate, fractured yolk sac rate, incubation period, hatching period, mass of newly hatched larvae, mantle length and survival rate after hatching 7 days were (90.0±4.1)%, (7.3±1.5)%, (25.50±0.35) d, (8.10±0.89) d, (0.213±0.011) g, (1.013±0.022) cm, (97.1±4.0)%, respectively. The effects of photoperiod on the hatching rate, incubation period, hatching period were significant, but there was no significant effect on fractured yolk sac rate, mass of newly hatched larvae, mantle length and survival rate after hatching 7 days. With the increases of illumination time, the hatching rate and hatching period first increased and then decreased. The optimum photoperiod was L:D (12 h:12 h). When exposed to this photoperiod environment, the hatching rate, fractured yolk sac rate, incubation period, hatching period, mass of newly hatched larvae, mantle length and survival rate after hatching 7 days were (88.7±1.8)%, (8.7±1.8)%, (25.00±0.50) d, (7.00±3.20) d, (0.209±0.005) g, (0.998±0.026) cm, (96.8±7.1)%, respectively. In conclusion, embryo hatchability of S. pharaonis preferred to low light intensity (30 µmol·m-2·s-1) and normal photoperiod L:D (12 h:12 h). In production practice, sunproof measures should be taken to keep the eggs in weak light condition.

Kinetics for Zinc Ion Induced Sepia Pharaonis Arginine Kinase Inactivation and Aggregation.

Arginine kinase is an essential enzyme which is closely related to energy metabolism in marine invertebrates. Arginine kinase provides a significant role in quick response to environmental change and stress. In this study, we simulated a tertiary structure of Sepia pharaonis arginine kinase (SPAK) based on the gene sequence and conducted the molecular dynamics simulations between SPAK and Zn(2+). Using these results, the Zn(2+) binding sites were predicted and the initial effect of Zn(2+) on the SPAK structure was elucidated. Subsequently, the experimental kinetic results were compared with the simulation results. Zn(2+) markedly inhibited the activity of SPAK in a manner of non-competitive inhibitions for both arginine and ATP. We also found that Zn(2+) binding to SPAK resulted in tertiary conformational change accompanying with the hydrophobic residues exposure. These changes caused SPAK aggregation directly. We screened two protectants, glycine and proline, which effectively prevented SPAK aggregation and recovered the structure and activity. Overall, our study suggested the inhibitory effect of Zn(2+) on SPAK and Zn(2+) can trigger SPAK aggregation after exposing large extent of hydrophobic surface. The protective effects of glycine and proline against Zn(2+) on SPAK folding were also demonstrated.

[Oxygen consumption rate of Sepia pharaonis embryos.] / 虎斑乌贼的胚胎耗氧率.

This research was conducted to unravel the variation of oxygen consumption rate during different developmental stages and the effects of different ecological factors on embryonic oxygen consumption rate of Sepia pharaonis. The oxygen consumption rates were measured at twelve deve-lopmental stages by the sealed volumetric flasks, and four embryonic developmental periods (oosperm, gastrula, the formation of organization, endoskeleton) were selected under various ecological conditions, such as salinity (21, 24, 27, 30, 33), water temperature (18, 21, 24, 27, 30 ℃) and pH (7.0, 7.5, 8.0, 8.5, 9.0). The results showed that the oxygen consumption rate rose along with the developmental progress, and distinctly differed from each other. The oxygen consumption rate was 0.082 mg·(100 eggs)-1·h-1 during oosperm period, and rose to 0.279 mg·(100 eggs)-1·h-1 during gastrula period, which was significantly higher than that of blastula period. Finally, the oxygen consumption rate rose to 1.367 mg·(100 eggs)-1·h-1 during hatching period. The salinity showed a significant effect on oxygen consumption rate during the formation of organization and endoskeleton formation stage (P<0.05), but no significant effect during oosperm and gastrula periods (P>0.05). The oxygen consumption rates of four studied embryonic stages all rose and then declined along with the increase of salinity, and reached the highest values [0.082, 0.200, 0.768 and 1.301 mg·(100 eggs)-1·h-1, respectively] at salinity 30. The water temperature had a significant effect on the embryo oxygen consumption rates of gastrula, and the formation of organization and endoskeleton formation stage (P<0.05), with the exception of oosperm (P>0.05). The oxygen consumption rates of four studied embryonic stages all rose and then declined along with the increase of temperature, and reached the highest values at 27 ℃ [0.082, 0.286, 0.806 and 1.338 mg·(100 eggs)-1·h-1, respectively]. The pH had no significant effect on the oxygen consumption rates of four embryonic stages (P>0.05). The oxygen consumption rates of four studied embryonic stages all rose and then declined along with the increase of pH. The oxygen consumption rates of gastrula, the formation of organization, endoskeleton reached the according highest values [0.281, 0.799 and 1.130 mg·(100 eggs)-1·h-1] at pH 8.5, but that during oosperm period occurred at pH 8.0 [0.116 mg·(100 eggs)-1·h-1].

[Effects of starvation and re-feeding on survival rate, growth and digestive enzyme activities of juvenile Sepia pharaonis.] / é¥¥é¥¿å’Œå†æŠ•å–‚å¯¹è™Žæ–‘ä¹Œè´¼å¹¼ä½“å­˜æ´»ã€ç”Ÿé•¿å’Œæ¶ˆåŒ–é ¶æ´»åŠ›çš„å½±å“.

To investigate the effects of starvation and re-feeding on survival rate, behavior, growth and digestive enzyme activities of juvenile Sepia pharaonis, the manipulative laboratory experiments were conducted with 0-6 days of starvation and 15 days of re-feeding to reveal the mechanism of compensatory growth. The results showed that starvation exerted a significant negative effect on the survival rate, growth, hepatosomatic index and digestive enzyme activities (P<0.05). The survival rate and digestive enzyme activities declined during the whole starvation process. After 3 days, the survival rate began to decline significantly, the decrease rate of body mass increased obviously and juveniles experienced some abnormal behaviors, such as inkjet, fighting and so on. The effects of starvation on digestive enzyme activities of juveniles were significant, and the digestive enzyme activities declined and then rose during the whole starvation process. The lowest amylase activity occurred after 4 days of starvation (0.07±0.02 U·mg-1·prot-1). The lowest lipase activity occurred after 2 days of starvation (18.47±2.07 U·g-1·prot-1), and the highest after 6 days (57.60±3.98 U·g-1·prot-1). The lowest pepsin and trypsin activities occurred after 5 days (1.98±0.59 U·mg-1·prot-1) and 4 days (186.68±20.72 U·mg-1·prot-1) of starvation, respectively. The effects of re-feeding on survival rate, growth, hepatosomatic index and digestive enzyme activities of juveniles were significant. The survival rate, specific growth rate, hepatosomatic index and feeding rate were negatively correlated with hunger processing duration. The survival rate, specific growth rate and hepatosomatic index showed no significant difference between 1 day starvation group and 2 days starvation group (P>0.05). The survival rate, specific growth rate and hepatosomatic index of 3 days to 6 days starvation groups were significantly lower than the control group. The feeding rates of 1 day and 2 days starvation groups were obviously higher than that of the control group. The feeding rate of 6 days starvation group was significantly lower than that of the control group. The amylase and lipase activities were not significantly different among different starvation treatments, whereas the pepsin and trypsin activities were significantly different, with the highest value in the control group (pepsin 7.06±0.64 U·mg-1·prot-1, trypsin 914.67±26.54 U·mg-1·prot-1) and the lo-west value in the group with 6 days of starvation (pepsin 3.21±0.57 U·mg-1·prot-1, trypsin 660.04±37.92 U·mg-1·prot-1). Six days of starvation would be the point of no-return for the juveniles, without any compensatory effect after starvation and re-feeding.

Complete mitochondrial genome of Gnathopogon taeniellus (Cypriniformes: Cyprinidae).

The complete mitochondrial genome of Gnathopogon taeniellus was first determined in this study. It is 16,596 bp in length, contains 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and one control region in the typical vertebrate gene order and transcriptional direction. There are total of 29 bp short overlaps and 34 bp non-coding intergenic spacers were found in the mitogenome. Overall nucleotide base composition of light strand is 29.3% A, 25.8% C, 17.9% G and 27.0% T. Two start codons (ATG and GTG) and two stop codons (TAG and TAA/T) were used in the protein-coding genes. The origin of light strand replication (OL) was identified between tRNA(Asn) and tRNA(Cys) genes and could fold a hairpin structure. The nucleotide composition of control region is 31.8% A, 20.9% C, 14.0% G and 33.3% T.

Effects of cadmium on the cuttlefish Sepia pharaonis' arginine kinase: unfolding kinetics integrated with computational simulations.

Arginine kinase is closely associated with adaptation to environmental stresses such as high salinity and heavy metal ion levels in marine invertebrates. In this study, the effects of Cd(2+) on the cuttlefish Sepia pharaonis' arginine kinase (SPAK) were investigated. SPAK was isolated from the muscles of S. pharaonis and upon further purification, showed a single band on SDS-PAGE. Cd(2+) effectively inactivated SPAK, and the double-reciprocal kinetics indicated that Cd(2+) induced non-competitive inhibition of arginine and ATP. Spectrofluorometry results showed that Cd(2+) induced tertiary structure changes in SPAK with the exposure of hydrophobic surfaces that directly induced SPAK aggregation. The addition of osmolytes, glycine, and proline successfully blocked SPAK aggregation and restored the conformation and activity of SPAK. Molecular dynamics simulations involving SPAK and Cd(2+) showed that Cd(2+) partly blocks the entrance of ATP to the active site, and this result is consistent with the experimental results showing Cd(2+)-induced inactivation of SPAK. These results demonstrate the effect of Cd(2+) on SPAK enzymatic function and unfolding, including aggregation and the protective effects of osmolytes on SPAK folding. This study provides concrete evidence of the toxicity of Cd(2+) in the context of the metabolic enzyme SPAK, and it illustrates the toxic effects of heavy metals and detoxification mechanisms in cuttlefish.

[Enrichment of Cd2+ and Hg2+ in Phascolosoma esculenta and their effects].

The accumulation of Cd2+ and Hg2+ in Phascolosoma esculenta and its effects on its growth and main nutrient components were investigated using atomic absorption spectrometer analysis and atomic fluorescence spectrometer examination. The results showed that within the experimental heavy metal concentrations, the amounts of Cd2+ and Hg2+ accumulated in the somatic muscles increased with increasing exposure time and reached their saturated levels at the end of the experiment. Exposure of higher heavy metal concentrations speeded up the accumulation of Cd2+ and Hg2+ and subsequently took less time to reach their saturated levels, which were greater than those of lower concentration groups. The rate of mass gain of P. esculenta decreased with increasing the heavy metal exposure concentrations. The combination exposure of Cd2+ and Hg2+ led to a significantly lower mass gain rate compared to those exposed to Cd2+ or Hg2+. The protein content of somatic muscles increased with the increase of exposure concentration and reached the maximum values at 0.05 and 0.02 mg · L(-1) for Cd2+ and Hg2+, respectively. After that, the protein content of somatic muscles began to decrease. The combined exposure of the two heavy metals showed similar effect trends but more significant impacts on the protein content of somatic muscles. The lipid content of somatic muscles decreased with increasing the concentration of Cd2+ or Hg2+ exposure, and the combination of Cd2+ and Hg2+ led to lower lipid content.

[Effects of temperature on the embryonic development and larval growth of Sepia lycidas].

A single-factor experiment was conducted to study the effects of different temperature (15, 18, 21, 24, 27, 30, and 33 degrees C) on the embryonic development and larval growth of Sepia lycidas, aimed to search for the optimum temperature for the development and growth of S. lycidas. The results showed that temperature had significant effects on the embryonic development and larval growth of S. lycidas (P < 0.05). The suitable temperature for hatching ranged from 21 degrees C to 30 degrees C, and the optimum temperature was 24 degrees C. At the optimum temperature, the hatching rate was (93.3 +/- 2.9)%, incubation period was (24.33 +/- 0.58) d, hatching period was (6.00 +/- 1.00) d, completely absorked rate of yolk sac was (96.4 +/- 3.1)%, and newly hatched larvae mass was (0.258 +/- 0.007) g. The effective accumulated temperature model was N = 284.42/(T-12.57). The suitable temperature for the larval survival and growth ranged from 21 degrees C to 30 degrees C, and the optimum temperature was from 24 degrees C to 27 degrees C. At the optimum temperature, the survival rate ranged from 70.0% to 73.3%, and the specific growth rate was from 2.4% to 3.8%.

[Effects of several ecological factors on the hatching of Sepiella maindroni wild and cultured eggs].

This paper compared the differences between Sepiella maindroni wild and cultured eggs, and studied the effects of temperature, salinity, hatching density, and egg type on the hatching rate and hatching time of the eggs. Wild eggs had better quality than cultured eggs. Among cultured eggs, small and black eggs had the best quality. For wild eggs, the optimum hatching temperature was 27 degrees C - 29 degrees C, and the optimum hatching salinity was 24.5-32.0. Hatching density had no significant effects on the hatching rate of wild eggs. For culturd Fol eggs, their hatching rate was 6.7% 30.0% when the temperature was 19 degrees C - 29 degrees C. No cultured eggs were hatched when the temperature was higher than 33 degrees C or lower than 17 degrees C. When the salinity was 19.5-32.0, the hatching rate of cultured eggs was 18.3%-25.0%. No hatching was observed when the salinity was below 17.0. Hatching density had no significant effects on the hatching rate of cultured eggs when air was provided, but the hatching rate was significantly affected when no air was provided.

[Oxygen consumption rate and effects of hypoxia stress on enzyme activities of Sepiella maindron].

The oxygen consumption rate and suffocation point of Sepiella maindroni were determined through the measurement of dissolved oxygen in control and experimental respiration chambers by Winkler's method, and the changes of S. maindroni enzyme activities under different levels of hypoxia stress were studied. The results indicated that the oxygen consumption rate of S. maindroni exhibited an obvious diurnal fluctuation of 'up-down-up-down', and positively correlated with water temperature (16 degrees C-28 degrees C) and illumination (3-500 micromol x m(-2) x s(-1)) while negatively correlated with water pH (6.25-9.25). With increasing water salinity from 18.1 to 29.8, the oxygen consumption rate had a variation of 'up-down-up', being the lowest at salinity 24. 8. Female S. maindroni had a higher oxygen consumption rate than male S. maindroni. The suffocation point of S. maindroni decreased with its increasing body mass, and that of (38.70 +/- 0.52) g in mass was (0.9427 +/- 0.0318) mg x L(-1). With the increase of hypoxia stress, the activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) decreased after an initial increase, lipase activity decreased, protease activity had a variation of 'decrease-increase-decrease', and lactate dehydrogenase (LDH) activity had a trend of increasing first and decreasing then. The enzyme activities were higher under hypoxia stress than under normal conditions.