Reproductive biology of Hemitripterus villosus in the Bohai Strait,China

To understand the reproductive biology of Hemitripterus villosus in the Bohai Strait,and fill the key knowledge gap in verifying reproductive seasonality and documenting gonadotropin dependent reproductive cycle of this species,a year-round detail study was conducted for the first time.In total,263 individuals were randomly sampled off the coasts of the Bohai Strait.Results show that and the overall female-to-male ratio(1.35:1)did not differ significantly from the 1:1 sex ratio.The length and weight relationship for females and males were regressed,depicting an isometric growth for both sexes.Four reproductive phases of the complete gonadotropin dependent reproductive cycle in both sexes were identified.The monthly variations in the gonadosomatic and hepatosomatic indexes for both sexes further indicated that this species spawns a single batch of eggs per year and the peak spawning period is from October to December.The average diameter of eggs ranged from 2.10 to 3.57 mm.The length at first sexual maturity was 224.87 mm for females and 241.26 mm for males.Significant positive relationships between absolute fecundity and fish size,and also gonadal weight were observed.H.villosus from the Bohai Strait exhibited smaller body size,smaller egg diameter,lower gonadosomatic index,lower absolute fecundity,and higher population extinction risk than the other populations’studied previously.Our findings contribute to understanding the status of this isolated westernmost population,and we emphasize that more efficient protection measures for the species and control measures are urgently required to improve the coastal environment in the Bohai Strait.

Eff ects of temperature on photosynthetic performance and nitrate reductase activity in vivo assay in Gracilariopsis lemaneiformis (Rhodophyta)

Gracilariopsis lemaneiformis is an economically-valued species and widely cultured in China at present.After being acclimated to diff erent growth temperatures(15,20,25,and 30°C)for 7 days,the relative growth rate(RGR),nitrate reductase activity,soluble protein content and chlorophyll a fl uorescence of G.lemaneiformis were examined.Results show that RGR was markedly aff ected by temperature especially at 20°C at which G.lemaneiformis exhibited the highest eff ective quantum yield of PSII[Y(II)]and lightsaturated electron transport rate(ETR max),but the lowest non-photochemical quenching.Irrespective of growth temperature,the nitrate reductase activity increased with the incubation temperature from 15 to 30°C.In addition,the greatest nitrate reductase activity was found in the thalli grown at 20°C.The value of temperature coeffi cient Q10 of alga cultured in 15°C was the greatest among those of other temperatures tested.Results indicate that the optimum temperature for nitrate reductase synthesis was relatively lower than that for nitrate reductase activity,and the relationship among growth,photosynthesis,and nitrate reductase activity showed that the optimum temperature for activity of nitrate reductase in vivo assay should be the same to the optimal growth temperature.

Comparison of the photo-acclimation potential of fl oating and benthic thalli of Sargassum horneri(Phaeophyta)during autumn and winter

Sargassum horneri is a foundational species and an important contributor to the fl oating seaweed stock along the northeastern coast of Asia.In this study,benthic and fl oating thalli of S.horneri were collected from Changdao Island(37°54′N,120°43′E),Bohai Bay,China.We conducted an in-situ and an indoor experiment to study the acclimation potential in S.horneri to abiotic conditions at sea surface in autumn and winter.Both benthic and fl oating thalli were cultured in situ for two months(from October to December)at diff erent depths:0 m above sea level(masl)and 3 m below sea level(mbsl),and their growth rate,biochemical content,and photosynthetic performance were compared.During the fi rst month of culture,the relative growth rate of fl oating thalli was 2-fold greater than that of benthic thalli at 0 masl.The photosynthetic rate of most thalli was signifi cantly higher at 0 masl than at 3 mbsl.In the indoor experiments,fl oating and benthic thalli were exposed to high light intensity(400μmol photons/(m^(2)·s)photosynthetically active radiation(PAR))for 21 d,and their photo-acclimation capacities were compared.Under high light intensity,the two types of thalli showed low maximum quantum yield(F_(v)/F_(m))and light utilisation effi ciency(α)but high light saturation point(E_(k)).Floating thalli showed higher photosynthetic rate and photoprotective ability than benthic thalli at high light intensity.The eff ective quantum yield of photosystem II[Y(II)]of both types of thalli recovered after a 6-day treatment with low light intensity(40μmol photons/(m^(2)·s)).These fi ndings suggest that S.horneri is highly acclimated to the sea surface environment,which possibly contributes to its rapid accumulation and long free-fl oating periods at the sea surface.

Blockade of the deubiquitinating enzyme USP48 degrades oncogenic HMGA2 and inhibits colorectal cancer invasion and metastasis

HMGA2,a pivotal transcription factor,functions as a versatile regulator implicated in the progression of diverse aggressive malignancies.In this study,mass spectrometry was employed to identify ubiquitin-specific proteases that potentially interact with HMGA2,and USP48 was identified as a deubiquitinating enzyme of HMGA2.The enforced expression of USP48 significantly increased HMGA2 protein levels by inhibiting its degradation,while the deprivation of USP48 promoted HMGA2 degradation,thereby suppressing tumor invasion and metastasis.We discovered that USP48 undergoes SUMOylation at lysine 258,which enhances its binding affinity to HMGA2.Through subsequent phenotypic screening of small molecules,we identified DUB-IN-2 as a remarkably potent pharmacological inhibitor of USP48.Interestingly,the small-molecule inhibitor targeting USP48 induces destabilization of HMGA2.Clinically,upregulation of USP48 or HMGA2 in cancerous tissues is indicative of poor prognosis for patients with colorectal cancer(CRC).Collectively,our study not only elucidates the regulatory mechanism of DUBs involved in HMGA2 stability and validates USP48 as a potential therapeutic target for CRC,but also identifies DUB-IN-2 as a potent inhibitor of USP48 and a promising candidate for CRC treatment.

Epinephrine promotes tumor progression and M2 polarization of tumor-associated macrophages by regulating the TRIM2-NF-kB pathway in colorectal cancer cells

Tumor-associated inflammation is an important component of the tumor microenvironment,and an important factor affecting tumor progression.In the tumor microenvironment,tumor-associated macrophages(TAMs)receive different stimuli and can be polarized into classically activated M1 macrophages and alternatively activated M2 macrophages.Many studies have indicated that the polarization of TAMs is closely related to tumor progression.

Can the scaling of plant nitrogen to phosphorus be altered by global change? An empirical test

Aims Global change may cause unparalleled supplies of soil nutrients and further lead to stoichiometric imbalance of nitrogen(N)and phosphorus(P)in terrestrial plants.While previous studies had reported the effects of global change factors on plant N,P contents and their ratios,few had examined whether or how these factors may influence the scaling of these two elements.Methods Taking advantage of a manipulative experiment with altered precipitation,warming and N addition,and using the general scaling function N=βPα,we examined how the scaling of plant N to P may respond to global change factors in a Loess grassland in northwestern China.Important Findings We found that precipitation reduction(PR)and warming decreased plant P concentrations,while N addition increased plant N concentrations,resulting in increased N:P ratios.The slopes of the linear regressions between plant N and P(i.e.log-transformed N versus P)did not change significantly,whereas the intercepts increased significantly under PR,warming and N addition.These results indicate that global change factors may not affect the synergistic variation of plant N and P,showing a closely coupled relationship between them.Our findings may help to better understand plant nutrient dynamics and element balance in a changing world.