A calmodulin-gated calcium channel links pathogen patterns to plant immunity.

Pathogen-associated molecular patterns (PAMPs) activate innate immunity in both animals and plants. Although calcium has long been recognized as an essential signal for PAMP-triggered immunity in plants, the mechanism of PAMP-induced calcium signalling remains unknown1,2. Here we report that calcium nutrient status is critical for calcium-dependent PAMP-triggered immunity in plants. When calcium supply is sufficient, two genes that encode cyclic nucleotide-gated channel (CNGC) proteins, CNGC2 and CNGC4, are essential for PAMP-induced calcium signalling in Arabidopsis3-7. In a reconstitution system, we find that the CNGC2 and CNGC4 proteins together-but neither alone-assemble into a functional calcium channel that is blocked by calmodulin in the resting state. Upon pathogen attack, the channel is phosphorylated and activated by the effector kinase BOTRYTIS-INDUCED KINASE1 (BIK1) of the pattern-recognition receptor complex, and this triggers an increase in the concentration of cytosolic calcium8-10. The CNGC-mediated calcium entry thus provides a critical link between the pattern-recognition receptor complex and calcium-dependent immunity programs in the PAMP-triggered immunity signalling pathway in plants.

The function of the cytoplasmic dynein light chain PTKM23 in the transport of PTSMAD2 during spermatogenesis in Portunus trituberculatus†.

Cytoplasmic dynein participates in transport functions and is essential in spermatogenesis. KM23 belongs to the dynein light chain family. The TGFß signaling pathway is indispensable in spermatogenesis, and Smad2 is an important member of this pathway. We cloned PTKM23 and PTSMAD2 from Portunus trituberculatus and measured their expression during spermatogenesis. PTKM23 may be related to cell division, acrosome formation, and nuclear remodeling, and PTSMAD2 may participate in regulating the expression of genes related to spermatogenesis. We assessed the localization of PTKM23 with PTDHC and α-tubulin, and the results suggested that PTKM23 functions in intracellular transport during spermatogenesis. We knocked down PTKM23 in vivo, and the expression of p53, B-CATAENIN and CYCLIN B decreased significantly, further suggesting a role of PTKM23 in transport and cell division. The localization of PTDIC with α-tubulin and that of PTSMAD2 with PTDHC changed after PTKM23 knockdown. We transfected PTKM23 and PTSMAD2 into HEK-293 T cells and verified their colocalization. These results indicate that PTKM23 is involved in the assembly of cytoplasmic dynein and microtubules during spermatogenesis and that PTKM23 mediates the participation of cytoplasmic dynein in the transport of PTSMAD2 during spermatogenesis.

Integrated multi-omics analyses reveal microbial community resilience to fluctuating low oxygen in the East China sea.

Climate change and eutrophication are accelerating ocean deoxygenation, leading to a global decline in oxygen levels. The East China Sea, frequently experiencing deoxygenation events, harbors diverse microbial communities. However, the response of these communities to the changing deoxygenation dynamics remains poorly understood. Here, we explored the composition and function of microbial communities inhabiting seawaters of the Changjiang Estuary and offshore areas. Our findings suggested that neutral processes significantly influenced the assembly of these communities. The overall bacterial composition demonstrated remarkable high stability across the oxygen gradient. Salinity exhibited a significantly stronger correlation with bacterial community structure than dissolved oxygen. Both metagenomics and metaproteomics revealed that all of the samples exhibited similar functional community structures. Heterotrophic metabolism dominated these sites, as evidenced by a diverse array of transporters and metabolic enzymes for organic matter uptake and utilization, which constituted a significant portion of the expressed proteins. O2 was the primary electron acceptor in bacteria even under hypoxic conditions, evidenced by expression of low- and high-affinity cytochrome oxidases. Proteins associated with anaerobic processes, such as dissimilatory sulfite reductases, were virtually undetectable. Untargeted liquid chromatography with tandem mass spectrometry analysis of seawater samples revealed a diverse range of dissolved organic matter (DOM) components in amino acids, lipids, organic acids, peptides, and carbohydrates, potentially fueling dominant taxa growth. Despite fluctuations in the abundance of specific genera, the remarkable similarity in community structure, function, and DOM suggests that this ecosystem possesses robust adaptive mechanisms that buffer against abrupt changes, even below the well-defined hypoxic threshold in marine ecosystem.

The Effect of Prohibitins on Mitochondrial Function during Octopus tankahkeei Spermiogenesis.

Mitochondria are essential for spermiogenesis. Prohibitins (PHBs; prohibitin 1, PHB1 or PHB, and prohibitin 2, PHB2) are evolutionarily conserved and ubiquitously expressed mitochondrial proteins that act as scaffolds in the inner mitochondrial membrane. In this study, we analyzed the molecular structure and dynamic expression characteristics of Ot-PHBs, observed the colocalization of Ot-PHB1 with mitochondria and polyubiquitin, and studied the effect of phb1 knockdown on mitochondrial DNA (mtDNA) content, reactive oxygen species (ROS) levels, and apoptosis-related gene expression in spermatids. Our aim was to explore the effect of Ot-PHBs on mitochondrial function during the spermiogenesis of Octopus tankahkeei (O. tankahkeei), an economically important species in China. The predicted Ot-PHB1/PHB2 proteins contained an N-terminal transmembrane, a stomatin/prohibitin/flotillin/HflK/C (SPFH) domain (also known as the prohibitin domain), and a C-terminal coiled-coil domain. Ot-phb1/phb2 mRNA were widely expressed in the different tissues, with elevated expression in the testis. Further, Ot-PHB1 and Ot-PHB2 were highly colocalized, suggesting that they may function primarily as an Ot-PHB compiex in O. tankahkeei. Ot-PHB1 proteins were mainly expressed and localized in mitochondria during spermiogenesis, implying that their function may be localized to the mitochondria. In addition, Ot-PHB1 was colocalized with polyubiquitin during spermiogenesis, suggesting that it may be a polyubiquitin substrate that regulates mitochondrial ubiquitination during spermiogenesis to ensure mitochondrial quality. To further investigate the effect of Ot-PHBs on mitochondrial function, we knocked down Ot-phb1 and observed a decrease in mtDNA content, along with increases in ROS levels and the expressions of mitochondria-induced apoptosis-related genes bax, bcl2, and caspase-3 mRNA. These findings indicate that PHBs might influence mitochondrial function by maintaining mtDNA content and stabilizing ROS levels; in addition, PHBs might affect spermatocyte survival by regulating mitochondria-induced apoptosis during spermiogenesis in O. tankahkeei.

Optimization of Sperm Cryopreservation Formulation in Portunus trituberculatus.

Portunus trituberculatus is a very important marine economic species, and its aquaculture industry has been developing rapidly. However, the phenomenon of marine wild capture of P. trituberculatus and germplasm degradation has become increasingly serious. It is necessary to develop the artificial farming industry and carry out germplasm resource protection, for which sperm cryopreservation technology is an effective method. This research compared three methods (mesh-rubbing, trypsin digestion, and mechanical grinding) for acquiring free sperm, and the best method was mesh-rubbing. Then, the optimal cryopreservation conditions were selected, and the optimal formulation was sterile calcium-free artificial seawater, the optimal cryoprotectant was 20% glycerol, and the best equilibrium time was 15 min at 4 °C. The optimal cooling program was suspending the straws at 3.5 cm on the liquid nitrogen surface for 5 min and then storing them in liquid nitrogen. Finally, the sperm were thawed at 42 °C. However, the expression of sperm-related genes and the total enzymatic activities of frozen sperm were significantly decreased (p < 0.05), which showed that sperm cryopreservation damaged the sperm. Our study improves the sperm cryopreservation technology and the yield of aquaculture in P. trituberculatus. Additionally, the study provides a certain technical basis for the establishment of a sperm cryopreservation library of crustaceans.

Expression Dynamics Indicate Potential Roles of KIF17 for Nuclear Reshaping and Tail Formation during Spermiogenesis in Phascolosoma esculenta.

Kinesin family member17 (KIF17), a homologous dimer of the kinesin-2 protein family, has important microtubule-dependent and -independent roles in spermiogenesis. Little is known about KIF17 in the mollusk, Phascolosoma esculenta, a newly developed mariculture species in China. Here, we cloned the open reading frame of Pe-kif17 and its related gene, Pe-act, and performed bioinformatics analysis on both. Pe-KIF17 and Pe-ACT are structurally conserved, indicating that they may be functionally conserved. The expression pattern of kif17/act mRNA performed during spermiogenesis revealed their expression in diverse tissues, with the highest expression level in the coelomic fluid of P. esculenta. The expressions of Pe-kif17 and Pe-act mRNA were relatively high during the breeding season (July-September), suggesting that Pe-KIF17/ACT may be involved in spermatogenesis, particularly during spermiogenesis. Further analysis of Pe-kif17 mRNA via fluorescence in situ hybridization revealed the continuous expression of this mRNA during spermiogenesis, suggesting potential functions in this process. Immunofluorescence showed that Pe-KIF17 co-localized with α-tubulin and migrated from the perinuclear cytoplasm to one side of the spermatid, forming the sperm tail. Pe-KIF17 and Pe-ACT also colocalized. KIF17 may participate in spermiogenesis of P. esculenta, particularly in nuclear reshaping and tail formation by interacting with microtubule structures similar to the manchette. Moreover, Pe-KIF17 with Pe-ACT is also involved in nuclear reshaping and tail formation in the absence of microtubules. This study provides evidence for the role of KIF17 during spermiogenesis and provides theoretical data for studies of the reproductive biology of P. esculenta. These findings are important for spermatogenesis in mollusks.

The Functions of Pt-DIC and Pt-Lamin B in Spermatogenesis of Portunus trituberculatus.

Cytoplasmic Dynein is a multiple-subunit macromolecular motor protein involved in the transport process of cells. The Dynein intermediate chain (DIC) is one of the subunits of Dynein-1. In our previous studies, we showed that Pt-DIC may play an important role in the nuclear deformation of spermiogenesis in Portunus trituberculatus. Lamin B is essential for maintaining nuclear structure and functions. Surprisingly, Pt-Lamin B was expressed not only in the perinucleus but also in the pro-acrosome during spermiogenesis in P. trituberculatus. Studies have also shown that Dynein-1 can mediate the transport of Lamin B in mammals. Thus, to study the relationship of Pt-DIC and Pt-Lamin B in the spermatogenesis of P. trituberculatus, we knocked down the Pt-DIC gene in P. trituberculatus by RNAi. The results showed that the distribution of Pt-DIC and Pt-Lamin B in spermiogenesis was abnormal, and the colocalization was weakened. Moreover, we verified the interaction of Pt-DIC and Pt-Lamin B via coimmunoprecipitation. Therefore, our results suggested that both Pt-DIC and Pt-Lamin B were involved in the spermatogenesis of P. trituberculatus, and one of the functions of Dynein-1 is to mediate the transport of Lamin B in the spermiogenesis of P. trituberculatus.

Berberine ameliorates the neurological dysfunction of the gastric fundus by promoting calcium channels dependent release of ACh in STZ-induced diabetic rats.

Background: It has been reported diabetic gastroparesis is related to diabetic autonomic neuropathy of the gastrointestinal tract, and berberine (BBR) could ameliorate diabetic central and peripheral neuropathy. However, the influence of BBR on the function and motility of the gastric fundus nerve is unclear. Methods: A diabetic rat model was constructed, and HE staining was used to observe the morphological changes in the gastric fundus. The changes in cholinergic and nitrogen-related neurochemical indexes and the effects of BBR on them were measured using Elisa. The effects of BBR on the neural function and motility of gastric fundus were investigated by electric field stimulation (EFS) induced neurogenic response in vitro. Results: In the early stage of STZ-induced diabetic rats, the contractile response of gastric fundus induced by EFS was disorder, disturbance of contraction amplitude, and the cell bodies of neurons in the myenteric plexus of gastric fundus presented vacuolar lesions. Administration with BBR could improve the above symptoms. BBR further enhanced the contraction response in the presence of a NOS inhibitor or the case of inhibitory neurotransmitters removal. Interestingly, the activity of ACh could affect NO release directly and the enhancement of BBR on contractile response was canceled by calcium channel blockers completely. Conclusions: In the early stage of STZ-induced diabetic rats, the neurogenic contractile response disorder of the gastric fundus is mainly related to cholinergic and nitrergic nerve dysfunction. BBR promotes the release of ACh mainly by affecting the calcium channel to improve the neurological dysfunction of the gastric fundus.

Mitochondrial Features and Expressions of MFN2 and DRP1 during Spermiogenesis in Phascolosoma esculenta.

Mitochondria can fuse or divide, a phenomenon known as mitochondrial dynamics, and their distribution within a cell changes according to the physiological status of the cell. However, the functions of mitochondrial dynamics during spermatogenesis in animals other than mammals and fruit flies are poorly understood. In this study, we analyzed mitochondrial distribution and morphology during spermiogenesis in Sipuncula (Phascolosoma esculenta) and investigated the expression dynamics of mitochondrial fusion-related protein MFN2 and fission-related protein DRP1 during spermiogenesis. The mitochondria, which were elliptic with abundant lamellar cristae, were mainly localized near the nucleus and distributed unilaterally in cells during most stages of spermiogenesis. Their major axis length, average diameter, cross-sectional area, and volume are significantly changed during spermiogenesis. mfn2 and drp1 mRNA and proteins were most highly expressed in coelomic fluid, a spermatid development site for male P. esculenta, and highly expressed in the breeding stage compared to in the non-breeding stage. MFN2 and DRP1 expression levels were higher in components with many spermatids than in spermatid-free components. Immunofluorescence revealed that MFN2 and DRP1 were consistently expressed and that MFN2 co-localizes with mitochondria during spermiogenesis. The results provide evidence for an important role of mitochondrial dynamics during spermiogenesis from morphology and molecular biology in P. esculenta, broadening insights into the role of mitochondrial dynamics in animal spermiogenesis.

Characterization of Mitochondrial Prohibitin in Opsariichthys bidens and Its Potential Functions in Spermatogenesis.

Spermatogenesis is the intricate and coordinated process by which spermatogonia develop into haploid differentiated spermatozoa. Mitochondria are essential for spermatogenesis, and prohibitin (PHB) is closely associated with mitochondrial structure and function during spermatogenesis. Although PHB has been implicated in spermatogenesis in some taxa, its roles in Opsariichthys bidens have not been determined. In this study, the expression patterns and potential functions of PHB in spermatogenesis in O. bidens were characterized using histological microscopic observations, PCR cloning, real-time quantitative PCR (qPCR), Western blotting (WB) and immunofluorescence (IF). The full-length cDNA of Ob-phb was 1500 bp encoding 271 amino acids. A sequence alignment demonstrated that the PHB protein is conserved among different animals. qPCR revealed that phb mRNA is widely distributed in O. bidens and highly expressed in the testes at stages IV and V. WB revealed that Ob-PHB is located in the mitochondria of testes. IF revealed the colocalization of PHB signals and mitochondria. Signals were detected around nuclei in spermatogonia and spermatocytes, gradually moving to the tail region during spermiogenesis, and finally aggregating in the midpiece. These results indicate that Ob-PHB was expressed in the mitochondria during spermatogenesis. In addition, this study proposed Ob-PHB may participate in the degradation of mitochondria and cell differentiation during spermatogenesis.

The potential function of KIF17 in large yellow croaker (Larimichthys crocea) spermatid remodeling: molecular characterization and expression pattern during spermiogenesis.

KIF17, which belongs to the kinesin-2 protein family, plays an indispensable role in mammalian spermiogenesis. However, the role of KIF17 in fish spermatid remodeling during spermiogenesis remains poorly understood. Therefore, we aimed to study the role of KIF17 in spermatid remodeling during Larimichthys crocea (L. crocea) spermiogenesis. The kif17 cDNA sequence, 3247 bp in length, was cloned from L. crocea testis, which consisted of a 347-bp 5'-untranslated region (UTR), 413-bp 3' -UTR, and 2487-bp open reading frame. Bioinformatic analyses revealed that KIF17 obtained from L. crocea (Lc-KIF17) exhibited a high sequence identity compared with those from other teleosts and possessed the structural features of other kinesin-2 proteins. Based on structural similarity, we speculate that the role of Lc-KIF17 may be similar to that of KIF17 in other animals. Lc-kif17 mRNA was diffusely expressed in L. crocea tissues and was highly expressed in the testis, especially at stage IV testicular development. Immunofluorescence analysis revealed that Lc-KIF17 signals colocalized with ß-tubulin signals and migrated from the perinuclear cytoplasm to the side of the nucleus where the tail forms during spermiogenesis. These findings revealed that KIF17 may be involved in L. crocea spermiogenesis. In particular, KIF17 may participate in spermatid remodeling by interacting with perinuclear microtubules during L. crocea spermiogenesis. Collectively, this study contributes to an improved understanding of the mechanism underlying L. crocea spermiogenesis and provides a basis for further research on L. crocea reproduction and development.

Expression and functional analysis of cytoplasmic dynein during spermatogenesis in Portunus trituberculatus.

The mechanism of acrosome formation in the crab sperm is a hot topic in crustacean reproduction research. Dynein is a motor protein that performs microtubule-dependent retrograde transport and plays an essential role in spermatogenesis. However, whether cytoplasmic dynein participates in acrosome formation in the crab sperm remains poorly understood. In this study, we cloned the cytoplasmic dynein intermediate chain gene (Pt-DIC) from Portunus trituberculatus testis. Pt-DIC is composed of a p150glued-binding domain, a dynein light chain (DLC)-binding domain, and a dynein heavy chain (DHC)-binding domain. The Pt-DIC gene is widely expressed in different tissues, showing the highest expression in the testis, and it is expressed in different stages of spermatid development, indicating important functions in spermatogenesis. We further observed the colocalization of Pt-DIC and Pt-DHC, Pt-DHC and tubulin, and Pt-DHC and GM130, and the results indicated that cytoplasmic dynein may participate in nuclear shaping and acrosome formation via vesicle transport. In addition, we examined the colocalization of Pt-DHC and a mitochondrion (MT) tracker and that of Pt-DHC and prohibitin (PHB). The results indicated that cytoplasmic dynein participated in mitochondrial transport and mitochondrial degradation. Taken together, these results support the hypothesis that cytoplasmic dynein participates in acrosome formation, nuclear shaping, and mitochondrial transport during spermiogenesis in P. trituberculatus. This study will provide valuable guidance for the artificial fertilization and reproduction of P. trituberculatus.

Effects of acute low temperature stress on the hormones and gene expression of glucocorticoid receptor of large yellow croaker Larimichthys crocea.

The neuroendocrine system of fish responds to low temperature via regulating hormones. To explore the adaptability of Larimichthys crocea to low temperature, the levels of the plasma cortisol, thyroid stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), total cholesterol (TC), and glucose were determined after exposure to low temperature and during subsequent rewarming. Furthermore, the mRNA expression of the glucocorticoid receptor (GR) gene was analyzed under the stress. We found that the levels of the plasma cortisol, TSH, T3, glucose, and TC increased under the low temperature stress, suggesting that elevated hormones may be conducive to promoting the mobilization of the glucose and lipid in L. crocea exposed to low temperature. During the rewarming period, the plasma cortisol level decreased, whereas the T3 level was still significantly higher than that in the control group. Notably, the plasma T4 level was unaffected by the temperature changes. Furthermore, the sequence alignment and phylogenetic tree analysis revealed that the GR protein of L. crocea had high homology and a similar protein structure with those from other teleosts. Under the low temperature stress, the GR mRNA expression increased in the brain and head kidney, whereas it basically returned to the control level following rewarming. These findings revealed the changes of the hormones and the potential function of the GR gene in L. crocea following exposure to low temperature, providing some insights into breeding low temperature-resistant varieties of L. crocea.

Cloning, Functional Characterization and Response to Cadmium Stress of the Thioredoxin-like Protein 1 Gene from Phascolosoma esculenta.

Cadmium (Cd) is a heavy metal toxicant and is widely distributed in aquatic environments. It can cause excessive production of reactive oxygen species (ROS) in the organism, which in turn leads to a series of oxidative damages. Thioredoxin (Trx), a highly conserved disulfide reductase, plays an important role in maintaining the intracellular redox homeostasis in eukaryotes and prokaryotes. Phascolosoma esculenta is an edible marine worm, an invertebrate that is extensively found on the mudflats of coastal China. To explore the molecular response of Trx in mudflat organisms under Cd stress, we identified a new Trx isoform (Trx-like protein 1 gene) from P. esculenta for the first time, designated as PeTrxl. Molecular and structural characterization, as well as multiple sequence and phylogenetic tree analysis, demonstrated that PeTrxl belongs to the Trx superfamily. PeTrxl transcripts were found to be ubiquitous in all tissues, and the highest expression level occurred in the coelomic fluid. Exposure to three sublethal concentrations of Cd resulted in the upregulation and then downregulation of PeTrxl expression levels over time in coelomic fluid of P. esculenta. The significant elevation of PeTrxl expression after 12 and 24 h of Cd exposure at 6 and 96 mg/L, respectively, might reflect its important role in the resistance to Cd stress. Recombinant PeTrxl (rPeTrxl) showed prominent dose-dependent insulin-reducing and ABTS free radical-scavenging abilities. After exposure to 96 mg/L Cd for 24 h, the ROS level increased significantly in the coelomic fluid, suggesting that Cd induced oxidative stress in P. esculenta. Furthermore, the injection of rPeTrxl during Cd exposure significantly reduced the ROS in the coelomic fluid. Our data suggest that PeTrxl has significant antioxidant capacity and can protect P. esculenta from Cd-induced oxidative stress.

A chloride efflux transporter, BIG RICE GRAIN 1, is involved in mediating grain size and salt tolerance in rice.

Grain size is determined by the size and number of cells in the grain. The regulation of grain size is crucial for improving crop yield; however, the genes and molecular mechanisms that control grain size remain elusive. Here, we report that a member of the detoxification efflux carrier /Multidrug and Toxic Compound Extrusion (DTX/MATE) family transporters, BIG RICE GRAIN 1 (BIRG1), negatively influences grain size in rice (Oryza sativa L.). BIRG1 is highly expressed in reproductive organs and roots. In birg1 grain, the outer parenchyma layer cells of spikelet hulls are larger than in wild-type (WT) grains, but the cell number is unaltered. When expressed in Xenopus laevis oocytes, BIRG1 exhibits chloride efflux activity. Consistent with this role of BIRG1, the birg1 mutant shows reduced tolerance to salt stress at a toxic chloride level. Moreover, grains from birg1 plants contain a higher level of chloride than those of WT plants when grown under normal paddy field conditions, and the roots of birg1 accumulate more chloride than those of WT under saline conditions. Collectively, the data suggest that BIRG1 in rice functions as a chloride efflux transporter that is involved in mediating grain size and salt tolerance by controlling chloride homeostasis.

RYBP modulates stability and function of Ring1B through targeting UBE3A.

Ring1 and yin yang 1-binding protein (RYBP) are central components of noncanonical polycomb-repressive complex 1 (nc-PRC1), which represses target gene expression and is required for normal organismal development. However, the molecular function of RYBP in this complex is obscure. In this study, we showed that RYBP inhibits the polyubiquitination-mediated proteasomal degradation of Ring1B independently of its ubiquitin (Ub)-protein isopeptide ligase (E3) ligase activity, leading to its stabilization and increased catalytic activity toward monoubiquitination of histone H2A at lysine 119. Mechanistic dissection further disclosed that RYBP directly binds to ubiquitin protein ligase E3A (UBE3A) to promote its ubiquitination and proteasomal degradation in an autoubiquitination-independent manner. The resultant reduction of UBE3A protein level alleviates its effect on ubiquitination-mediated degradation of Ring1B, therefore resulting in increased stability and enhanced transcriptional repressor activity on its target genes. Thus, our current findings lay a foundation for understanding how RYBP functions in nc-PRC1 complexes, which is involved in development, stem cell maintenance, and carcinogenesis.-Li, M., Zhang, S., Zhao, W., Hou, C., Ma, X., Li, X., Huang, B., Chen, H., Chen, D. RYBP modulates stability and function of Ring1B through targeting UBE3A.

Characterisation, expression and possible functions of prohibitin during spermatogenesis in the silver pomfret Pampus argenteus.

Mitochondria play an important role in spermatogenesis, and some mitochondrial proteins are specifically related to this process. In this study we investigated the cytological characteristics of spermatogenic cells, including mitochondrial dynamics, during spermatogenesis in Pampus argenteus. In addition, we characterised the mitochondria-related protein prohibitin (PHB), which has been reported to play roles in mitochondrial dynamics and animal fertility. The full-length cDNA of the P. argenteus phb gene (Pa-phb) is 1687bp, including a 102-bp 5'-untranslated region (UTR), a 772-bp 3'-UTR and an 813-bp open reading frame encoding 271 amino acids. The predicted P. argenteus PHB protein (Pa-PHB) contains three functional domains (a transmembrane domain, an SPFH domain (the conserved region of stomatins, prohibitins, flotillins and HflK/C) and a coiled-coil domain) and exhibits high similarity with its homologue in other animals. The Pa-phb gene was widely expressed in all tissues examined, especially the liver and heart. We primarily focused on Pa-phb expression during spermatogenesis after observing the cytological features of male germ cells, and found that Pa-phb transcripts were detected throughout the course of development of male germ cells. Notably, we observed colocalised signals of Pa-PHB and mitochondria, which were distributed in the cytoplasm around the nucleus in spermatogonia, spermatocytes and early spermatids, tended to move to one side of the cell in middle spermatids and, finally, were colocalised in the sperm midpiece. These observations indicate that Pa-PHB is primarily localised in mitochondria during spermatogenesis, indicating that it has a role in mitochondria. Based on the results of this and previous studies regarding the essential roles of PHB in mitochondria and spermatogenesis in animals, we propose a functional model for PHB during spermatogenesis, including possible roles in the proliferation of spermatogonia and in the regulation of mitochondrial morphology and function in spermatogenic cells.

The interaction of CaM7 and CNGC14 regulates root hair growth in Arabidopsis.

Oscillations in cytosolic free calcium determine the polarity of tip-growing root hairs. The Ca2+ channel cyclic nucleotide gated channel 14 (CNGC14) contributes to the dynamic changes in Ca2+ concentration gradient at the root hair tip. However, the mechanisms that regulate CNGC14 are unknown. In this study, we detected a direct interaction between calmodulin 7 (CaM7) and CNGC14 through yeast two-hybrid and bimolecular fluorescence complementation assays. We demonstrated that the third EF-hand domain of CaM7 specifically interacts with the cytosolic C-terminal domain of CNGC14. A two-electrode voltage clamp assay showed that CaM7 completely inhibits CNGC14-mediated Ca2+ influx, suggesting that CaM7 negatively regulates CNGC14-mediated calcium signaling. Furthermore, CaM7 overexpressing lines phenocopy the short root hair phenotype of a cngc14 mutant and this phenotype is insensitive to changes in external Ca2+ concentrations. We, thus, identified CaM7-CNGC14 as a novel interacting module that regulates polar growth in root hairs by controlling the tip-focused Ca2+ signal.

Expression and potential functions of KIF3A/3B to promote nuclear reshaping and tail formation during Larimichthys polyactis spermiogenesis.

KIF3A and KIF3B are homologous motor subunits of the Kinesin II protein family. KIF3A, KIF3B, and KAP3 form a heterotrimeric complex and play a significant role in spermatogenesis. Here, we first cloned full-length kif3a/3b cDNAs from Larimichthys polyactis. Lp-kif3a/3b are highly related to their homologs in other animals. The proteins are composed of three domains, an N-terminal head domain, a central stalk domain, and a C-terminus tail domain. Lp-kif3a/3b mRNAs were found to be ubiquitously expressed in the examined tissues, with high expression in the testis. Fluorescence in situ hybridization (FISH) was used to analyze the expression of Lp-kif3a/3b mRNAs during spermiogenesis. The results showed that Lp-kif3a/3b mRNAs had similar expression pattern and were continuously expressed during spermiogenesis. From middle spermatid to mature sperm, Lp-kif3a/3b mRNAs gradually localized to the side of the spermatid where the midpiece and tail form. In addition, we used immunofluorescence (IF) to observe that Lp-KIF3A protein co-localizes with tubulin during spermiogenesis. In early spermatid, Lp-KIF3A protein and microtubule signals were randomly distributed in the cytoplasm. In middle spermatid, however, the protein was detected primarily around the nucleus. In late spermatid, the protein migrated primarily to one side of the nucleus where the tail forms. In mature sperm, Lp-KIF3A and microtubules accumulated in the midpiece. Moreover, Lp-KIF3A co-localized with the mitochondria. In mature sperm, Lp-KIF3A and mitochondria were present in the midpiece. Therefore, Lp-KIF3A/KIF3B may be involved in spermiogenesis in L. polyactis, particularly during nuclear reshaping and tail formation.

Vanadium compounds induced damage of human umbilical vein endothelial cells and the protective effect of berberine.

This study was conducted to investigate the damage caused by vanadium compounds and to explore the protective effects of berberine (BBR) in human umbilical vein endothelial cells (HUVECs). BBR is a biologically active small molecule found in Coptis rhizome, a remedy used in traditional Chinese medicine to treat diabetes. BBR has also been shown to lower blood glucose in diabetic patients. MTT assay was performed to observe the influence of bis(acetylacetonato)-oxidovanadium [VO(acac)2] or sodium metavanadate (NaVO3) and BBR on viability of HUVECs. The monolayer permeability of the HUVECs was assessed by measuring the transendothelial electrical resistance (TER). The endothelial nitric oxide synthase (eNOS) activity was detected by ELISA. Flow cytometry was performed to detect the generation of reactive oxygen species (ROS). The results showed that the viability of HUVECs was decreased by treatment with vanadium compounds 50-400 µM in a concentration-dependent manner, while 0.01-1 µM BBR effectively protected HUVECs from the inhibitory effects of vanadium compounds on cell viability. Also 100 and 200 µM VO(acac)2 induced high permeability and decreased eNOS activity in HUVECs. While 0.01-1 µM BBR showed no improvement in the permeability, and failed to reverse the VO(acac)2-induced changes of eNOS activity, but BBR treatment increased the eNOS activity in control cells. The addition of 200 µM VO(acac)2 significantly induced ROS generation in HUVECs, while 0.01 or 0.1 µM BBR reversed the change of ROS. In summary, BBR has protective effects in HUVECs damage induced by vanadium compounds, which is not mediated by eNOS, but related to reduced intracellular ROS.