Chicken manure-derived biochar enhanced the potential of Comamonas testosteroni ZG2 to remediate Cd contaminated soil.

The combined remediation of Cd-contaminated soil using biochar and microorganisms has a good application value. In this study, the effect of chicken manure-derived biochar on CdCO3 precipitation induced by Comamonas testosteroni ZG2 was investigated. The results showed that biochar could be used as the carrier of strain ZG2, enhance the resistance of strain ZG2 to Cd, and reduce the toxicity of Cd to bacterial cells. Cd adsorbed by biochar could be induced by strain ZG2 to form CdCO3 precipitation. Strain ZG2 could also induce CdCO3 precipitation when biochar was added during precipitation formation and fermentation broth formation. The CdCO3 precipitation could enter the pores of the biochar and attach to the surface of the biochar. The single and combined effects of strain ZG2 and biochar could realize the remediation of Cd-contaminated soil to a certain extent. The overall effect was in the order of strain ZG2 with biochar > biochar > strain ZG2. The combination of strain ZG2 and biochar reduced soil available Cd by 48.2%, the aboveground biomass of pakchoi increased by 72.1%, and the aboveground Cd content decreased by 73.3%. At the same time, it promoted the growth and development of the root system and improved the microbial community structure of the rhizosphere soil. The results indicated that chicken manure-derived biochar could enhance the stability of CdCO3 precipitation induced by strain ZG2, and strain ZG2 combined with biochar could achieve a more stable remediation effect on Cd-contaminated soil.

Comparative metabolomic analysis reveals Ni(II) stress response mechanism of Comamonas testosteroni ZG2.

The focus on the toxicity of nickel (Ni(II)) in animal and human cells has increased recently. Ni(II) contamination hazards to animals and humans can be reduced by bioremediation methods. However, one of the limitation of bioremediation bacteria in soil remediation is that they cannot survive in moderate and heavy contamination Ni(II)-contaminated environments. Therefore, the Ni(II) response mechanism of Comamonas testosteroni ZG2 which has soil remediation ability in high-concentration Ni(II) environment must be elucidated. The results demonstrated that the ZG2 strain can survive at 350 mg/L concentration of Ni(II), but the growth of ZG2 was completely inhibited under the concentration of 400 mg/L Ni(II) with significant alterations in the membrane morphology, adhesion behavior, and functional groups and serious membrane damage. Furthermore, the metabolic analysis showed that Ni(II) may affect the adhesion behavior and biofilm formation of the ZG2 strain by affecting the abundance of metabolites in amino acid biosynthesis, aminoacyl-tRNA biosynthesis, ABC transporter, and cofactor biosynthesis pathways, and inhibiting its growth. This study provides new evidence clarifying the response mechanism of Ni(II) stress in the ZG2 strain, thus playing a significant role in designing the strategies of bioremediation.

Acute toxic effects of diclofenac exposure on freshwater crayfish (Procambarus clarkii): Insights from hepatopancreatic pathology, molecular regulation and intestinal microbiota.

In this study, we exposed adult male crayfish (Procambarus clarkii) to different concentrations of diclofenac (DCF) for 96 h. In the meantime, we investigated the alternations of hepatopancreatic pathology, molecular regulation and intestinal microbiota of P. clarkii exposed to DCF. The results demonstrated DCF led to histological changes including epithelium vacuolization and tubule lumen dilatation in the hepatopancreas. Transcriptome sequencing analysis showed that 642 and 586 genes were differentially expressed in the hepatopancreas of P. clarkii exposed to 1 and 10 mg/L DCF, respectively. DCF could affect the functions of antioxidation, immunity and metabolism of hepatopancreas by inducing the abnormal expressions of immune- and redox-related genes. GO enrichment results demonstrated that 10 mg/L DCF exposure could modulate the processes of molting, amino sugar metabolism, protein hydrolysis and intracellular protein translocation of P. clarkii. Additionally, the abundances of bacterial families including Shewanellaceae, Bacteroidaceae, Vibrionaceae, Erysipelotrichaceae, Aeromonadaceae, Moraxellaceae, etc. in the intestine were significantly changed after DCF exposure, and the disruption of intestinal flora might further cause abnormal intestinal metabolism in P. clarkii. This study provides novel mechanistic insights into the toxic effects of anti-inflammatory drugs on aquatic crustaceans.

Response mechanism of psychrotolerant Bacillus cereus D2 towards Ni (II) toxicity and involvement of amino acids in Ni (II) toxicity reduction.

The toxic effect of Nickel (Ni (II)) on humans and animals has been previously addressed. Owing to the important application of psychrotolerant bacteria in Ni (II) damage remediation in contamination sites at low temperatures, the response mechanism of psychrotolerant bacteria to Ni (II) toxicity must be elucidated. Therefore, the effect of Ni (II) toxicity on a psychrotolerant Bacillus cereus D2 was studied, showing a way to alleviate the Ni (II) toxicity in strain D2. The results showed that strain D2 growth was completely inhibited at a concentration of 100 mg/L of Ni (II). The main effects of Ni (II) toxicity on strain D2 were membrane damage and reactive oxygen species-dependent oxidative stress. Additionally, Ni (II) toxicity resulted in dysregulation of the cell cycle in strain D2. Furthermore, metabolomic analysis showed that the biosynthesis of amino acids and ABC transporters were significantly affected, and the relative abundance of seven important amino acids changed in a concentration-dependent manner. Addition of 20 mM or 5 mM amino acids to 100 mg/L Ni (II)-treated strain D2 restored its growth. This study provides insights into the way to alleviate the Ni (II) toxicity in strain D2, thus contributing to the development of bioremediation strategies.

CspB and CspC are induced upon cold shock in Bacillus cereus strain D2.

Bacillus cereus D2, a psychrotrophic strain, plays an essential role in the restoration of heavy metal-contaminated soils, especially at low temperatures. However, the cold shock response mechanisms of this strain are unclear. In this study, the cold shock response of B. cereus D2 was characterized; as per the Arrhenius curve, 10 °C was chosen as the cold shock temperature. Six cold shock-like proteins were found and temporarily named cold shock protein (Csp)1-6; the respective genes were cloned and identified. Quantitative real-time PCR results showed that csp1, csp2, csp3, and csp6 were overexpressed under cold shock conditions. Interestingly, after cloning the respective encoding genes into the pET-28a (+) vector and their subsequent transformation into E. coli BL21 (DE3), the strains expressing Csp2 and Csp6 grew faster at 10 °C, showing a large number of bacteria. These results suggest that Csp2 and Csp6 are the major cold shock proteins in B. cereus D2. Of note, the comparison of amino acid sequences and structures showed that Csp2 and Csp6 belong to the CspB and CspC families, respectively. Additionally, we show that the number of hydrophobic residues is not a determining feature of major Csps, while, on the other hand, the formation of an α-helix in the context of a leucine residue is the most dominant difference between major and other Bacillus and E. coli Csps.

A psychrotolerant Ni-resistant Bacillus cereus D2 induces carbonate precipitation of nickel at low temperature.

Psychrotolerant bacteria play a particularly important role in the remediation of heavy metal in contamination sites at low temperatures. In the current study, a psychrotolerant Ni-resistant bacterial strain, identified as Bacillus cereus D2, was isolated from a nickel mining area in China. The isolated strain could produce a large amount of urease enzyme (194.6 U/mL), grow well in harsh environmental conditions at a temperature of 10 °C, and at a Ni (II) concentration up to 400 mg/L. Also, under the low temperature (10 °C), this strain has been revealed to induce carbonate precipitation (Ni2CO3(OH)2·H2O) through biomineralization for removing the high efficiency of Ni ions (73.47%) from the culture solution. Furthermore, strain D2 could immobilize the DTPA-Ni in contaminated soil under the case of the laboratory condition at 10 °C. These data support that the psychrotolerant bacterial strain D2 may play an important role in remediation technology by eliminating Ni ions from the contaminated soil at low temperatures.

Extracellular polymeric substance from Rahnella sp. LRP3 converts available Cu into Cu5(PO4)2(OH)4 in soil through biomineralization process.

Soil contamination by toxic heavy metals such as copper is a serious problem. In this study, the extracellular polymeric substance (EPS) extracted from Rahnella sp. LRP3 was found with the potential of immobilizing Cu-polluted in soil. The EPS could bond to Cu (II) through functional groups (polysaccharides, amide, proteins, and carboxyl groups), which further developed into the porous sphere with a diameter of 20 µm. Besides, EPS could induce the formation of Cu5(PO4)2(OH)4 crystal by the biomineralization process. Finally, the EPS in the culture solution reduced 89.4 mg/kg of DTPA-Cu content by 78.99% in soil for 10 d under the condition of 25 °C via biomineralization. The results demonstrated that EPS produced by Rahnella sp. LRP3 will be a promising factor in the remediation of Cu contaminated soil.

Novel biomass-derived smoke-like carbon as a supercapacitor electrode material.

In this present work, smoke-like carbon was successfully fabricated from a bio-waste fungal substrate crude polysaccharide for the first time. The as-prepared products possess smoke-like structures, ultra-high specific surface area (S BET: 2160 m2 g-1) and a high content of micropores (microporous surface area of 60%, with a nanopore size of 0.70 nm), which can increase the specific capacitance, representing a wonderful structure for electrochemical energy storage devices. The as-prepared sample displayed an excellent specific capacitance of 152 F g-1 at 5 A g-1 in the three-electrode configuration and exhibited maximal densities of 6.8-10.2 W h kg-1 under power outputs of 253.4-24.3 kW kg-1. We believe that this work demonstrates a simple, green and low-cost route by using agricultural residue to prepare applicable carbon materials for use in energy storage devices.

Rahnella sp. LRP3 induces phosphate precipitation of Cu (II) and its role in copper-contaminated soil remediation.

Microbially induced phosphate precipitation (MIPP) is an advanced bioremediation technology to immobilize heavy metals in soil. In this study, an indigenous bacterial strain LRP3, identified as Rahnella sp., was isolated from Cu-contaminated dark brown soil in the mining area. Strain LRP3 could produce phytase and alkaline phosphatase to degrade phytic acid, which released soluble phosphate to the bacterial culture. Due to the metabolism of bacterial growth, the pH value of bacterial culture was increased. The minimum inhibitory concentration of Cu (II) to bacterial growth in solution was up to 130 mg/L. The bacterial culture could rapidly precipitate Cu (II) in solution through MIPP. The analysis results of Scanning Electron Microscope-Energy Dispersive Spectroscopy (SEM-EDS), Fourier Transform-Infrared Spectrometer (FTIR), and X-ray Diffraction (XRD) revealed that the precipitate form by bacterial culture was rod-shaped Cu3(OH)3PO4 crystal with a diameter of 10 µm. The bacterial culture decreased the content of DTPA-Cu of 83 mg/kg soil in the soil by 58.2%, 61.5% and 75.8% after 5, 10 and 30 days of incubation, respectively, at the temperature of 25 °C. The results indicate that MIPP-based bioremediation by Rahnella sp. LRP3 is a practical, environmental friendly technology for the cleaning-up of copper-contaminated soil.

Biodegradation of 17ß-estradiol by Bacterial Co-culture Isolated from Manure.

Animal wastes are potential sources of natural and steroidal estrogen hormones into the environment. These hormones can be removed by microorganisms with induced enzymes. Two strains of 17ß-estradiol-degrading bacteria (LM1 and LY1) were isolated from animal wastes. Based on biochemical characteristics and 16 S rDNA gene sequences, we identified strains LM1 and LY1 as belonging to the genus of Acinetobacter and Pseudomonas, respectively. Bacterial co-culture containing LM1 and LY1 bacterial strains could rapidly remove approximately 98% of E2 (5 mg L-1) within 7 days. However, strains LM1 and LY1 degraded 77% and 68% of E2 when they were incubated alone, respectively. More than 90% of 17ß-estradiol (E2, ≤ 20 mg L-1) could be removed by bacterial co-culture. Low C/N ratio (1:35) was more suitable for bacterial growth and E2 degradation. The optimal pH for bacterial co-culture to degrade E2 ranged from 7.00 to 9.00. Coexisting sodium acetate, glucose and sodium citrate decreased E2 degradation in the first 4 days, but more E2 was removed when they were depleted. The growth of the bacterial co-culture was not significantly decreased by Ni, Pb, Cd or Cu at or below 0.8, 1.2, 1.6 or 0.8 mg L-1, respectively. These data highlight the usefulness of bacterial co-culture in the bioremediation of estrogen-contaminated environments.

Chromium(VI) transport and fate in unsaturated zone and aquifer: 3D Sandbox results.

The simulation of Cr(VI) behavior in an unsaturated zone and aquifer, using a 3D experimental set-up were performed to illustrate the distribution, transport and transformation of Cr(VI), and further to reveal the potential harm of Cr(VI) after entering the groundwater. The result indicated that chromium(VI) was transported in the vertical direction, meanwhile, was transported in the horizontal direction under the influence of groundwater flow. The direction and distance away from the pollution source zone had great effect on the chromium(VI) concentration. At the sampling sites near the pollution source zone, there was a sudden increase of chromium(VI) concentration. The concentration of chromium(III) concentration in some random effluent samples was not detected. Chromium had not only transported but also had fraction and specie transformation in the unsaturated zone and aquifer. The relative concentration of residue fraction chromium was decreased with time. The content of Fe-Mn oxide fraction chromium was increased with time. The relative content of exchangeable and carbonate-bound fraction chromium was lower and the content variations were not obvious. Chromium(VI) (91-98%) was first reduced to chromium(III) rapidly. The oxidation reaction occurred later and the relative content of chromium(VI) was increased again. The presence of manganese oxides under favorable soil conditions can promote the reoxidation of Cr(III) to Cr(VI).

CspE is Overproduced by Temperature Downshift in the Acinetobacter johnsonii DBP-3.

The denitrifying bacterium Acinetobacter johnsonii strain DBP-3 which was capable of removing phosphate, nitrate, and ammoniacal salt is psychrotolerant, whereas, the cold shock response mechanisms or the cold shock proteins (Csps) was unclear. In this article, the optimal growth temperature (25 °C) and cold shock temperature (7.5 °C) were determined firstly by an Arrhenius plot of the growth of the strain DBP-3. Then, among the seven cold shock-like protein genes which were cloned and identified referenced by A. johnsonii SH046 genome, qRT-PCR and shotgun-LTQ mass spectrometry showed that Csp3 and Csp4 were overexpressed under cold shock condition. Furthermore, Western blotting confirmed the result with the antibodies against Csp3 and Csp4 prepared by ourselves. Finally, the phylogenetic analysis showed that the similarity percent between Csp3 and Csp4 was 76.85 %, and Csp3 and Csp4 belonged to CspE family. The results indicated that CspE is overproduced by temperature downshift and may play an important role in the psychrotolerant process of strain DBP-3.

A novel transcriptional repressor PhaR for the steroid-inducible expression of the 3,17ß-hydroxysteroid dehydrogenase gene in Comamonas testosteroni ATCC11996.

Comamonas testosteroni is able to catabolize a variety of steroids and polycyclic aromatic hydrocarbons and might be used in the bioremediation of contaminated environments. 3,17ß-Hydroxysteroid dehydrogenase (3,17ß-HSD) from C. testosteroni is a member of the short-chain dehydrogenase/reductase (SDR) superfamily and a key enzyme in steroid degradation. The genome of C. testosteroni ATCC11996 was sequenced in our previous work. In addition to the gene coding for 3,17ß-HSD (ßhsd), a novel transcriptional repressor phaR gene (phaR) which locates 2290 bp upstream of the ßhsd gene was found. PhaR knock-out mutants of C. testosteroni were prepared and shown to grow better than wild-type C. testosteroni in the presence of 1 mM testosterone, 0.5 mM estradiol or 0.5 mM cholesterol in both Standard 1 Nutrient (SIN) medium and 1:10 diluted SIN medium. After 1 mM testosterone induction, 3,17ß-HSD expression in the mutant was 2.5 times higher than in wild type C. testosteroni. Accordingly, PhaR is a repressor that controls 3,17ß-HSD expression. Moreover, phaR knock-out mutants grow at higher rates and produce more protein in the presence of steroids as carbon source. However, ELISA results showed that 0.5 mM estradiol and cholesterol could not induce ßhsd gene expression in both wild-type and mutant C. testosteroni. Probably, in addition to the ßhsd gene, PhaR regulates some other genes that relate to steroid degradation. The genes coding for PhaR and 3,17ß-HSD together with their promoter domains were cloned into plasmids pK18 and pUC19. Escherichia coli HB101 was co-transformed with these plasmids. The results suggest that PhaR is a repressor, which might bind on a special ßhsd promoter domain (214 bp). A 2509 bp DNA fragment that contained a putative promoter for the ßhsd gene (without the phaR gene) was cloned into plasmid pUC2.5-3. The plasmid was transformed into HB101 (E. coli) and induced with testosterone. As a result, 3,17ß-HSD expression was at a high level, but could not be further enhanced by testosterone. Taken together, phaR knock-out mutants have better ability to degrade steroids than wild-type C. testosteroni ATCC11996 and might therefore be used in bioremediation.

Isolation of nitrobenzene degrading strain Pseudomonas NB001 and application in the bioremediation of polluted water body.

A bacterium using nitrobenzene (NB) as a sole source of carbon, nitrogen and energy was isolated from NB-contaminated water body by the enrichment technology. It was identified as Pseudomonas NB001 by the phylogenetic analysis based on 16S rDNA sequence and the biochemical and physiological characteristics. Degradation of NB by strain NB001 was concomitant with the release of nitrite. Activities of catechol2,3-dioxygenase in strain NB001 cells grown in the culture fluid were higher than that in cells under any other conditions (P < 0.05). Under the pure culture conditions, 98.4% of NB at initial concentration of 50 mg L(-1) was removed in 136 hours. Glucose at starting concentration of 100 mg L(-1) delayed the onset of the exponential phase of NB degradation and weakened the degradation ability of per cell in the pure culture systems. In the river water, 89.5% of NB was degraded in 8 days. Suspended matter obviously increased the degradation rate of NB in the early stages, but decreased in the final stages. Cd(2+) and Hg(2+) significantly weakened the ability of the strain to degrade NB at initial concentrations of 10.0 mg L(-1) and 5.0 mg L(-1), respectively. The results would offer useful information for the application of strain NB001 in the bioremediation or the control of NB-contaminated environment.

Reduced somatostatin in hypothalamus of young male mouse increases local but not circulatory GH.

The release of growth hormone (GH) from the pituitary gland is primarily inhibited by somatostatin (SRIF) from the hypothalamus via interactions with five types of SRIF receptors (SSTRs). However, the inhibition mechanism of SRIF on GH has not been fully examined. In this study, we repressed the hypothalamic SRIF in young male mice by stereotaxic injection of the lentiviral-shRNA against SRIF to investigate the role of hypothalamic SRIF on hormone secretion in the GH/IGF-1 axis. We found that the reduction of SRIF in hypothalamus was associated with an increase in the protein, but not the mRNA level, of the GH in the pituitary where SSTR 2 and SSTR 5 act importantly. Interestingly, the level of blood circulatory SRIF, GH, IGF-1 and the body weight were not significantly influenced by the downregulation of hypothalamic SRIF. Our findings provide insights into the mechanisms underlying the inhibition of SRIF on GH secretion.

[Research advances in microbial degradation of nitrobenzene and its substituted compounds].

Nitrobenzene and its substituted compounds are a group of priority pollutants characterized by chemical stability, high toxicity, and biological accumulation. To treat the waste water and gas containing nitrobenzene and its substituted compounds and to remedy the environment polluted by these compounds, microbial degradation had advantages over other methods. This paper summarized the research advances in the microbial degradation of nitrobenzene and its substituted compounds by terms of the acclimation and screening of degradation strains, degradation pathways and mechanisms, co-metabolism, chemotaxis, and molecular genetics. Further studies should be made on the construction and application of engineering bacteria. In the microbial remediation of environment polluted by nitrobenzene and its substituted compounds, co-metabolism and synergetic degradation of co-strains would play an important role.

Effects of exogenous testosterone on testicular function during the chronic phase of spinal cord injury: dose effects on spermatogenesis and Sertoli cell and sperm function.

INTRODUCTION: Exogenous testosterone has been shown to attenuate spinal cord injury (SCI)-related regression of spermatogenesis in the rat. The current experiment investigated the effects of exogenous testosterone in testicular and sperm functions in the rat during the chronic phase of SCI. METHODS: Chronic SCI rats were given subcutaneous implants of testosterone-filled silastic capsules (TC). Northern blot cDNA hybridization was used to measure testicular levels of Sertoli cell- and germ cell-specific transcripts. Western blot and immunohistochemistry were used to determine protein level and cellular localization, respectively, of cyclic adenosine monophosphate-responsive element modulator (CREM) in the testes. Flow cytometry was used to determine sperm viability and mitochondrial potential. RESULTS: Spontaneous restoration of spermatogenesis occurred in 7 of the 8 untreated SCI rats. Although exogenous testosterone restored complete spermatogenesis in all SCI rats, regressed seminiferous epithelium remained in 30% to 70% of tubular cross sections in these rats. These effects were associated with altered responses of germ cell-specific mRNA transcripts to exogenous testosterone, and abnormal cellular distribution of CREM. Sperm of untreated SCI rats exhibited lowered motility, viability, and mitochondrial potential. Implantation of 10 cm of TC worsened sperm motility in sham control and SCI rats, but restored sperm viability and mitochondrial potential in SCI rats. CONCLUSION: Administration of exogenous testosterone to SCI rats during the chronic phase of injury failed to facilitate spermatogenic restoration over that achieved in untreated SCI rats. Abnormalities in postmeiotic spermatogenic differentiation could contribute to these effects, and perhaps the production of sperm with abnormal morphology and/or functions during the chronic phase of SCI.

Alteration of cyclic adenosine 3',5'-monophosphate signaling in rat testicular cells after spinal cord injury.

INTRODUCTION: Earlier studies demonstrated that the effects of spinal cord injury (SCI) on spermatogenesis were associated with altered Sertoli cell responses to treatment with follicle-stimulating hormone (FSH) and/or testosterone (T). Because of the importance of the cyclic adenosine 3',5'-monophosphate (cAMP) signal pathway in hormonal actions on Sertoli cells and spermatogenesis, the purpose of this study was to determine whether cAMP signaling in testicular cells is altered after SCI. METHODS: Rats with SCI were treated with FSH, T, or FSH + T for 7 or 14 days. Northern blot cDNA hybridization was used to measure testicular levels of Sertoli and germ cell-specific transcripts encoded by genes that contain cAMP responsive element (CRE) and/or steroid hormone responsive element (HRE). Cellular distribution of CRE modulator (CREM) was determined by immunohistochemistry. RESULTS: Treatment of sham control rats with FSH or T + FSH for 2 weeks resulted in decreases in mRNAs for CREM and CRE binding protein (CREB). Concomitantly, levels of mRNA for Sertoli cell inhibin alpha and germ cell-specific protamine 1 (Pm-1), transition protein 2 (TP-2), and lactate dehydrogenase C (LDHC) were all reduced. In contrast, identical FSH and/or T treatments resulted in increases in levels of CREM and CREB mRNAs in the testes of SCI rats; these effects were associated with similar changes in mRNAs for inhibin alpha, Pm-1, TP-2, and LDHC. The effects of SCI on CREM expression were corroborated by similar changes in its distribution in testicular cells. CONCLUSION: SCI is associated with changes in FSH and/or T regulation of cAMP/CRE and HRE signaling in testicular cells. These effects may mediate the effects of SCI on spermatogenesis.

Spinal cord contusion impairs sperm motility in the rat without disrupting spermatogenesis.

Our previous studies demonstrated various abnormalities in spermatogenesis after spinal cord injury (SCI) in cord-transected rats. In this study, we examined whether abnormalities in spermatogenesis in SCI rats were related to the degree of SCI. We used spinal cord-contused (SCC) rats as a model. Adult male Sprague-Dawley rats were subjected to various degrees of cord contusion caused by the weight of a rod dropped from different heights (12.5, 25, 50, and 75 mm) using a New York University IMPACTOR. Testicular histology revealed persistent complete spermatogenesis in all SCC rats 4, 8, or 14 weeks after cord contusion regardless of the extent of SCI. Northern blot complementary DNA (cDNA) hybridization revealed transient but significant decreases in the levels of Sertoli cell-specific transcripts in SCC rats. In addition, levels of messenger RNA (mRNA) transcripts for germ cell-specific transition protein-2 and protamine-1 were consistently decreased in these rats. Such effects were related to the height of the weight drop and were associated with reduced levels of mRNA for cyclic adenosine monophosphate (cAMP) responsive element modulator (CREM). These results demonstrated specific effects of SCI on spermiogenesis and were consistent with altered cAMP signaling in testicular cells after SCI. Sperm motility was also significantly decreased in SCC rats and was related to the height of weight drop. Normal sperm motility recovered only in those rats injured by weight drop from 12.5- and 25-mm heights. In summary, current results demonstrate persistent abnormalities in spermiogenesis and sperm motility in rats that suffered spinal cord contusion by weight drop. Such effects were related to the height of the weight drop and thus to the extent of SCI.

Androgen and retinoic acid interaction in LNCaP cells, effects on cell proliferation and expression of retinoic acid receptors and epidermal growth factor receptor.

BACKGROUND: Modulation of the expression of retinoic acid receptors (RAR) alpha and gamma in adult rat prostate by testosterone (T) suggests that RAR signaling events might mediate some of the androgen effects on prostate cells. METHOD: In this study, we examined the interactions between T and retinoic acid (RA) in cell growth of human prostate carcinoma cells, LNCaP, and their relationship with the expression of RAR and epidermal growth factor receptor (EGF-R). RESULTS: Both T and RA, when administered alone, stimulated 3H-thymidine incorporation in LNCaP cells in a dose-dependent manner; the effect of each agent was reciprocally attenuated by the other agent. Testosterone treatment of LNCaP cells also resulted in dose dependent, biphasic increases in RAR alpha and gamma mRNAs; increases paralleled that of 3H-thymidine incorporation and were attenuated by the presence of 100 nM RA. These results suggest a link between RAR signaling and the effect of T on LNCaP cell growth. Gel electrophoretic mobility shift assays revealed the presence of putative androgen responsive element (ARE) in the promoter region of RAR alpha gene, suggesting that a direct AR-DNA interaction might mediate the effects of T on RAR alpha gene. Furthermore, treatment of LNCaP cells with 20 nM T resulted in an increase in EGF-R. In contrast, EGF-R was suppressed by 100 nM RA that also suppressed the effect of T. CONCLUSIONS: Current results demonstrate interactions between T and RA in the expression of RARs and cell growth in LNCaP cells. The presence of putative ARE in the promoter of the RAR alpha gene suggests that AR-DNA interaction might mediate the effects of T on RAR alpha gene. The opposite effects of T and RA on the expression of RAR and EGF-R suggest that signal events of these receptors might be involved in the interaction between T and RA in the control of LNCaP cell growth.