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Background: Patients with triple-negative breast cancer (TNBC) tend to develop visceral metastasis within five years, making them the most challenging BC patients to treat. The MAP7 protein family is a group of microtubule-binding proteins with a well-known role in microtubule-related cell migration, but its role in metastasis-related properties of TNBC remains unclear., Methods: qRT-PCR and western blot were used to validate mRNA and protein expression of the MAP7 family in the isogenic pairs of TNBC cell lines with low and high metastasis potential. Functional characterization of MAP7D3 was carried out using cell-based and mouse models. The clinical association between MAP7D3 and TNBC was established using datasets in the public domain., Results: MAP7D3 expression was consistently upregulated in the metastatic subline IV2 and 468-LN at both mRNA and protein levels. Knockdown of MAP7D3 inhibited the 3D colony-forming ability, cell migration, and invasion ability of IV2 and 468-LN, indicating its significant contribution to the metastasis phenotypes. Mechanistically, inhibition of MAP7D3 could significantly increase the sensitivity of metastatic TNBC cells to docetaxel and gemcitabine treatment by reducing the expression of proteins related to breast cancer-initiating cells (BCICs) and drug resistance, as well as suppressing the activity of Rac1. The animal study showed that the depletion of MAP7D3 drastically reduced TNBC tumor growth and impaired the metastatic capability of TNBC cells. Elevated expression of MAP7D3 was found in the metastatic lymph nodes and was significantly associated with advanced stage and higher grade TNBC. Moreover, MAP7D3 expression was significantly correlated with the TNBC population, and its high expression was significantly associated with lymph node metastasis and poor survival outcomes of patients with TNBC., Conclusion: Our study indicates that targeting MAP7D3 could be a promising therapeutic strategy for addressing the progression of TNBC, and MAP7D3 may serve as a novel predictive biomarker for the survival outcomes of triple-negative breast cancer., (© 2023. BioMed Central Ltd., part of Springer Nature.)

This research investigates the relationships between CO 2 emissions, the economy, renewable energy consumption, green financing, and foreign direct investment in BRICS nations from 2000 to 2019 under the effect of higher education. The stationarity of the data was evaluated using three unit root tests: ADF-Fisher, Levin, Lin, and Chin and Im, Pesaran, and Shin. The panel autoregressive distributed lag approach identified the long-run and short-run elasticities. The empirical findings demonstrate that variables cointegrate. In the long run, renewable energy, economic growth, green finance, foreign direct investment, and higher education all influence CO 2 emissions; however, in the short run, only economic growth, renewable energy, and higher education influence CO 2 emissions. The findings also indicate that higher education increases dramatically at the individual and societal levels, reducing CO 2 emissions in the short and long term. The overall empirical study of group and economy is supported by the results of robust statistics. In light of the results, the BRICS economies are advised to collaborate for sustainable growth while preserving environmental quality. Moreover, the BRICS countries should prioritize investing in the growth of higher education and enhancing the use of renewable energy for sustainable development., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The abnormal expression and regulation of circular RNA (circRNA) is involved in the occurrence and development of a variety of tumors. The current study aimed to determine the role of circRNA&#95;141539 in esophageal squamous cell carcinoma (ESCC). CircRNA&#95;141539 expression in ESCC was detected via circRNA chip analysis and verified via reverse transcription-quantitative PCR. Associations between circRNA&#95;141539, patient clinicopathological characteristics and prognosis were also statistically analyzed. Additionally, the effects of circRNA&#95;141539 on ESCC cell proliferation and invasion were assessed. A dual-luciferase assay was performed to analyze the interaction between circRNAs, microRNAs (miRs) and mRNAs. The results revealed that circRNA&#95;141539 was significantly up-regulated in patients with ESCC. Furthermore, high circRNA&#95;141539 expressions were significantly associated with TNM stage, differentiation and poor prognosis, revealing high diagnostic value (P<0.05). Furthermore, circRNA&#95;141539 overexpression promoted cell proliferation and invasion, while circRNA&#95;141539 silencing inhibited cell proliferation and invasion (P<0.05). The dual-luciferase reporter assay identified that circRNA&#95;141539 directly binds to miR-4469 and also revealed that cyclin-dependent kinase-3 (CDK3) was negatively regulated by miR-4469. The results indicated that circRNA&#95;141539 served as an oncogenic factor in ESCC by sponging miR-4469 and activating CDK3 expression. circRNA&#95;141539 may present as a novel diagnostic and prognostic biomarker and a therapeutic target for patients with ESCC.

Bacterial foraging optimization (BFO) algorithm is a novel swarm intelligence optimization algorithm that has been adopted in a wide range of applications. However, at present, the classical BFO algorithm still has two major drawbacks: one is the fixed step size that makes it difficult to balance exploration and exploitation abilities; the other is the weak connection among the bacteria that takes the risk of getting to the local optimum instead of the global optimum. To overcome these two drawbacks of the classical BFO, the BFO based on self-adaptive chemotaxis strategy (SCBFO) is proposed in this paper. In the SCBFO algorithm, the self-adaptive chemotaxis strategy is designed considering two aspects: the self-adaptive swimming based on bacterial search state features and the improvement of chemotaxis flipping based on information exchange strategy. The optimization results of the SCBFO algorithm are analyzed with the CEC 2015 benchmark test set and compared with the results of the classical and other improved BFO algorithms. Through the test and comparison, the SCBFO algorithm proves to be effective in reducing the risk of local convergence, balancing the exploration and the exploitation, and enhancing the stability of the algorithm. Hence, the major contribution in this research is the SCBFO algorithm that provides a novel and practical strategy to deal with more complex optimization tasks., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2020 Huang Chen et al.)

In this paper, we first presents a high accuracy epileptic electroencephalogram (EEG) classification algorithm. EEG data of epilepsy patients are preprocessed, segmented, and decomposed to intrinsic mode functions, from which features are extracted. Two classifiers are trained based on linear discriminant analysis (LDA) to classify EEG data into three types, i.e., normal, spike, and seizure. We further in-depth investigate the changes of the decision values in LDA on continuous EEG data. An epileptic EEG visualization and sonification algorithm is proposed to provide both temporal and spatial information of spike and seizure of epilepsy patients. In the experiment, EEG data of six subjects (two normal and four seizure patients) are included. The experiment result shows the proposed epileptic EEG classification algorithm achieves high accuracy. As well, the visualization and sonification algorithm exhibits a great help in nursing seizure patients and localizing the area of seizures.

Aim: To investigate fibroblast growth factor receptor 4 (FGFR4) protein expression in Chinese patients with resectable gastric cancer (GC) and the association with clinicopathological characteristics and survival., Methods: One hundred and seventy-five GC patients who underwent curative surgical procedures were enrolled in this study. The protein expression of FGFR4 in formalin-fixed, paraffin-embedded (FFPE) GC tissues was determined by immunohistochemical (IHC) analysis. Patient clinicopathological data and survival information were also collected and χ(2) statistical analysis was performed to analyze FGFR4 protein expression in the subgroups with differing clinicopathological characteristics including; gender, age, tumor location, differentiation, tumor-node-metastasis stage, macroscopic type, depth of invasion, lymph node metastases, distant metastasis, neural invasion and vascular invasion. Furthermore, some common molecular markers of GC in our cancer center, including p53, p27, topoisomerase IIα (Topo IIα) were also determined by IHC and their association with FGFR4 protein expression evaluated. The probability of survival for different subgroups with different clinicopathological characteristics was calculated using the Kaplan-Meier method and survival curves plotted using the log rank test., Results: Seventy seven cases (44%) were found to have high expression of FGFR4 protein. Significantly different FGFR4 expression was observed between gastric cancers with differing expression of Topo IIα (log rank χ(2) = 9.4760, P = 0.0236). No significant differences were observed between subgroups defined by any of the other clinicopathological characteristics. The median survival time of the FGFR4 high expression (77 cases) and low expression groups (98 cases) was 27 mo and 39 mo, respectively. The five-year survival rates and median survival times of gastric cancers with high FGFR4 expression were worse than those with low expression (30.8% vs 39.2%, 27 mo vs 39 mo), respectively, however, no significant difference was observed in survival time (log rank χ(2) = 1.0477, P = 0.3060). Survival analysis revealed that high expression of FGFR4 was a predictor of poor outcome in GC patients if the tumor was small (less than or equal to 3 cm in size) (log rank χ(2) = 5.5033, P = 0.0190), well differentiated (log rank χ(2) = 7.9757, P = 0.0047), and of T1 or T2 stage invasion depth (log rank χ(2) = 4.8827, P = 0.0271)., Conclusion: Our results suggest that high tumor expression of FGFR4 protein is not an independent risk factor for GC cancer initiation, but is a useful prognostic marker for GC patients when the tumor is relatively small, well differentiated, or in the early stages of invasion.

Splenic artery aneurysm is one of the most common visceral aneurysms, and patients with this type of aneurysm often present without symptoms. However, when rupture occurs, it can be a catastrophic event. Although most of these aneurysms can be treated with percutaneous embolization, some located in uncommon parts of the splenic artery may make this approach impossible. We present a patient with an aneurysm in the proximal splenic artery, close to the celiac trunk, which was treated by laparoscopic ligation only, without resection of the aneurysm, and with long-term preservation of splenic function.

Purpose: Optineurin is a pathogenic gene associated with primary open angle glaucoma (POAG), in which the retinal ganglion cells (RGCs) are targeted. However, the functions of optineurin, particularly in RGCs, are currently not clear. We introduced optineurin siRNA into cultured retinal ganglion cell 5 (RGC-5) and PC12 cells to determine the cellular and molecular mechanisms underlying the role of optineurin in POAG., Methods: We constructed four optineurin siRNA-expressing plasmids, and transiently transfected them into PC12 cells. Quantitative real-time PCR, western blot, and fluorescent microscopy were used to determine optineurin expression and select the most effective optineurin siRNA to construct RGC-5 and PC12 stable transfected cells. Dimethylthiazolyl diphenyl tetrazolium bromide (MTT) assay and flow cytometry were applied to investigate the role of optineurin siRNA in cell growth and apoptosis. Gene microarray and quantitative real-time PCR were used to screen and validate differentially expressed genes in optineurin siRNA transfected PC12 and RGC-5 cells., Results: siRNA effectively downregulated optineurin expression in RGC-5 and PC12 stable transfected cells. Optineurin siRNA significantly inhibited cell growth and increased apoptosis in RGC-5 and PC12 cells. Microarray analysis identified 112 differentially expressed genes in optineurin siRNA transfected RGC-5 cells. Quantitative real-time PCR and western blot confirmed that the expression of brain-derived neurotrophic factor (Bdnf), neurotrophin-3(Ntf3), synaptosomal-associated protein 25(Snap25), and neurofilament, light polypeptide(Nefl) was significantly downregulated in RGC-5 and PC12 cells transfected with optineurin siRNA., Conclusions: Our study suggested that optineurin downregulation by siRNA in RGCs was an in vitro model for studying the mechanisms of optineurin effects on POAG. Neuroprotective factor and axonal transport genes may be involved in the development of POAG and could be novel targets for treating POAG due to optineurin mutation.

Background: Increasing evidence suggests that stress can trigger and exacerbate atopic dermatitis (AD). Psychotherapy is becoming more important in the treatment of AD patients. Yokukansan (YKS, Yi-Gan San in Chinese), a traditional Japanese medicine, has been widely utilized in the treatment of neurosis, insomnia and anxiety especially in Asian countries. Furthermore, it was reported that YKS inhibited skin lesions in socially isolated mice but not in group-housed mice. Therefore, in the present study it was investigated whether or not YKS was effective in the treatment of AD using socially isolated NC/Nga mice., Objective: The present study was designed to assess the effect of YKS on the development of AD-like lesions in socially isolated NC/Nga mice to obtain information about its usefulness in the treatment of AD., Methods: Ten-week-old male NC/Nga mice were socially isolated under conventional conditions. YKS was administered orally to mice at the dose of 0.5% or 1.0% together with diet. The efficacy of YKS was evaluated by assessing skin lesion severity, scratching behaviors, skin hydration, and infiltration of inflammatory cells in the skin. Grooming behaviors evoked by social isolation stress and serum corticosterone levels were also measured., Results: Oral administration of YKS to socially isolated NC/Nga mice resulted in the inhibition of exacerbation of AD-like skin lesions. It seemed that the inhibition of exacerbation of AD-like skin lesions observed in NC/Nga mice might be due to suppression of the scratching and grooming behaviors, inhibition of the infiltration of mast cells and eosinophils, and retention of humidity in the skin. Serum corticosterone levels were also significantly inhibited in the 1%-YKS-treated mice as compared with those of the control mice. There were no significant differences in the levels of serum total IgE and nerve growth factor (NGF) between the YKS-treated mice and the non-treated control mice., Conclusion: YKS inhibited the development of AD-like skin lesions in socially isolated NC/Nga mice by suppressing scratching and infiltration of inflammatory cells in the skin. These results indicate that YKS possesses an anti-itching property, and its anti-itching may be partly through attenuation on social isolation stress. It is expected that YKS might provide an effective alternative therapy for AD in human patients.

The biological effect of Ho3+ on Halobacterium halobium R1 growth was analyzed using the microcalorimetric method. Using the LKB-2277 Bioactivity Monitor with the ampoule method at 37 degrees C, the thermogenic curves of the growth of H. halobium R1 were obtained. Then, the maximum power (P (m)) and the growth rate constants (k) were determined, and the values of P (m) and k were linked to the concentration of Ho3+. In all, the addition of Ho3+ cause a decrease in the maximum heat production and growth rate constants. To confirm the results, the shapes of H. halobium R1 cell addition with Ho3+ using a transmission electron microscope (TEM) were observed. According to the thermogenic curves and TEM photos of H. halobium R1 under different conditions, it is clear that the metabolic mechanism of H. halobium R1 growth has been changed with the addition of Ho3+.

The biological effect of Ho3+ on Halobacterium halobium R1 growth was analyzed by a microcalorimetric technique. By means of LKB-2277 Bioactivity Monitor, ampoule method at 37 degrees C, we obtained the thermogenic curves of H. halobium R1 growth. To analyze the results, the maximum power (Pm) and the growth rate constants (k) were determined, which show that values of Pm and k are linked to the concentration of Ho3+. In all, the addition of Ho3+ causes a decrease of the maximum heat production and growth rate constants. For comparison, we observed the shapes of H. halobium R1 cell by means of transmission electron microscope (TEM). According to the thermogenic curves and TEM photos of H. halobium R1 under different conditions, it is clear that metabolic mechanism of H. halobium R1 growth has been changed with the addition of Ho3+.

A series of 4-aminoquinazoline derivatives is prepared by the nucleophilic substitution reaction of 6,7,8-trimethoxy-4-chloroquinazoline and aryl amine. The structures of the compounds are confirmed by elemental analysis, IR, and (1)H NMR spectral data. The compounds are also evaluated for their ability to inhibit tumor cells PC3, A431, Bcap-37, and BGC823 by MTT assays. Among them, 6b and 6e are found as potent inhibitors, with IC(50) values ranging from 5.8 to 9.8microM, in vitro assay.

Unlabelled: Natural IgM can recognize apoptotic cells, but the molecular structure and the role in macrophage phagocytosis of apoptotic cells remain unclear., Objectives: (1) To examine the binding of previously isolated natural IgM (3B4) to apoptotic cells and its effects on phagocytosis of apoptotic cells. (2) To characterize the molecular structure of 3B4., Methods: 3B4 binding to apoptotic thymocytes was examined by flow cytometry. Polyreactivity of 3B4 was assayed by ELISA. PKH26-labeled Macrophages were incubated with PKH67-stained apoptotic cells in the presence of 3B4. Macrophages phagocytosis of apoptotic cell was evaluated by flow cytometry. The DNA segments of 3B V(H) and V(K) were sequenced and analyzed., Results: 3B4 IgM recognized late apoptotic cells. Polyreactive-recognitions of lysophosphatidylcholine (LPC) as well as some autoantigens were observed in 3B4. Phagocytosis of late apoptotic cells was increased in the presence of 3B4. The V(H) and V(K) genes of 3B4 showed a germline gene context, while N-sequences and nucleotide loss were observed in CDR3., Conclusion: 3B4 promotes macrophage phagocytosis of late apoptotic cells in a complement-independent process. 3B4 has a germline configuration and is possibly ligand-selected. Out experiments suggest an independent role of natural IgM as opsonin in clearance of late apoptotic cells.

We herein report 2 cases of multiple lobular capillary hemangiomas after scalding. The patients exhibited papules and nodules on the scalded areas after healing. Histopathological examination of the lesions showed capillary proliferation in the upper dermis with edematous stroma containing inflammatory infiltrates predominantly composed of neutrophils. Biopsy tissue and secretion specimens from lesions of case 1 were cultured for bacteria, and both grew Enterobacter cloacae. Ultrastructural examination revealed features typical of a lobular capillary hemangioma and viral inclusion bodies in the epidermis of case 1. Multiple lobular capillary hemangiomas after scalding are rarely reported. Trauma may play an important role in the development of this rare condition. Accumulation of similar cases and its precise observation is needed to confirm the associations and to establish an etiological link between the disease and the pathogens.

Background: Heat shock protein 70 (HSP70) is expressed highly in epithelial tumours associated closely with human papillomavirus 16 (HPV16) infections. However, evidence about the direct relationship between HSP70 expression and HPVs infections are still lacking. In the present study, we examined the expression of HSP70 in keratinocytes introduced with HPV16 E6/E7 oncogenes., Methods: Stable transfected cells were established by transfection of the plasmids pLXSN16E6/E7 into cultured primary keratinocytes and subsequently selected by plasmid specific selection antibiotic (G418) at the required concentration. The expression of HSP70 in pLXSN16E6/E7 transfected keratinocytes was determined by Western blot. The correlation of HSP70 expression and E6/E7 transfection was further confirmed by doubly labelled immunofluorescent staining., Results: Compared to non-transfected keratinocytes, there was a significant trend for higher levels of HSP70 in pLXSN16E6/E7 transfected keratinocytes. Doubly labelled immunofluorescent staining experiment showed that the co-localization of HPV16 E6/E7 and HSP70 in transfected keratinocytes was observed and increased expression of HSP70 was strongly associated with the transfection of HPV16 E6/E7., Conclusions: Our studies demonstrated increased levels of HSP70 proteins in keratinocytes stably transfected by HPV16 E6/E7 oncogenes. It suggests that the expression of HSP70 is modulated by HPV16 E6/E7 proteins, which may be involved in HPV16 E6/E7 induced immortalization.

A microcalorimetric technique was used to evaluate the influence of Er3+ on Halobacterium halobium R1 growth. By means of a LKB-2277 Bioactivity Monitor ampoule method, we obtained the thermogenic curves of H. halobium R1 growth at 37 degrees C. In order to analyze the results, the relationship between k and C was obtained. The addition of Er3+ in low concentration cause a decrease of the maximum heat production Pmax and growth rate constants k; however, Er3+ in a high concentration might promote growth of H. halobium R1. When Er3+ is in a much higher concentration, the growth of H. halobium R1 is inhibited completely. For comparison, the shapes of H. halobium R1 cells were observed by means of transmission electron microscope (TEM). According to the thermogenic curves and TEM photos of H. halobium R1 under different conditions, it is clear that the metabolic mechanism of H. halobium R1 growth has been changed with the addition of Er3+.

Though people had recognized the pivotal function of CaCl(2) during DNA transformation into Escherichia coli, the mechanism of divalent Ca(2+) cation inducing E. coli competence development is still unknowable. Quantum dots (QDs), as a new fluorescent probe, being applied in biology research, had aroused great interest. We explored the penetrability of E. coli competent cells membrane using QDs and proved directly that competent cells were more permeable than that of noncompetent. The results are significant on understanding the problems of the microbiological genetics.

Aim: To investigate the therapeutic effects of Lycium barbarum polysaccharide (LBP) on mitomycin C (MMC)-induced myelosuppressive mice., Methods: Mice were intravenously injected with MMC 150 mg/kg for two consecutive days from day -1 to day 0 to produce severe myelosuppression, and then treated by s.c. injections of LBP (100 or 200 mg/kg/day) from days 0 to 6. Blood samples were collected from the tail veins of mice on days 7, 10, 12, 14, 17, 19, 21, 24 and 27, and peripheral white blood cells (WBC), red blood cells (RBC), hemoglobin (HGB) and platelet counts (PLT) etc. were monitored., Results: LBP at 100 mg/kg (LBP-L) on day 14 and LBP at 200 mg/kg (LBP-H) on days 10, 14, 17, 19 and 21, significantly ameliorated the decrease of peripheral RBC, HGB and hematocrit (HCT) of myelosuppressive mice compared to the control. LBP-L on days 12 and days 14 and LBP-H on days 10, 12, 14, 17, 19 and 21, significantly enhanced peripheral PLT recovery of myelosuppressive mice compared to the control. LBP-H on days 12, 17, 19 and 21, significantly inhibited the increase of mean platelet volume (MPV) of myelosuppressive mice compared to the control. LBP showed no obviously effect on neutropenia induced in mice by MMC., Conclusion: LBP is effective on peripheral RBC and PLT recovery of MMC-induced myelosuppressive mice.

The RM07 DNA fragment from Halobacterium halobium was inserted upstream of chloramphenicol acetyltransferase (cat) reporter gene in pKK232-8 in two different orientations (positively or negatively), generating the RM07-cat fusion plasmids pRM07-1 (+) and pRM07-1 (-). These two plasmids and pKK232-8 were transformed into Escherichia coli HB101 respectively, then the antibiotic resistance level and the chloramphenicol acetyltransferase protein concentration of different transformants were detected. The research results revealed that HB101/pRM07-1 (+) was resistant to chloramphenicol and could grow on the plate containing chloramphenicol, but HB101/pRM07-1 (-) and HB101/pKK232-8 were sensitive to it. Therefore, the results suggested that the positive RM07 fragment had promoter activity in Escherichia coli while the negative RM07 fragment did not. Site-directed mutagenesis of RM07 was performed by PCR mutagenesis method. The effect of specific nucleotide mutations on the chloramphenicol resistance level of different transformants was detected. The different transformants containing different nucleotide mutations were inoculated on the plates containing various concentrations of chloramphenicol and then incubated at the same time. The change of chloramphenicol resistance level reflected the change of promoter activity. By using this method, the important nucleotide responsible for the promoter function of RM07 in Escherichia coli was determined. The promoter activity of RM07 in Escherichia coli was also improved greatly by modifying the nucleotide component.

By using an LKB-2277 Bioactivity Monitor, cycle-flow method, the thermogenic curves of aerobic growth for Bacillus thuringiensis cry II strain at 28 degrees C have been obtained. The metabolic thermogenic curves of B. thuringiensis cry II contained two distinct patterns: the first reflects the changes during the bacterial growth phase and the second corresponds to the sporulation phase. From these thermogenic curves in the absence and presence of Sm(3+) ions, the thermokinetic parameters such as the growth rate constants k, the interval time tau(I), the maximum power P (max 1) and heat-output Q(log) for log phase, the maximum power P (max 2) and heatoutput Q(stat) for stationary phase, the heat-output Q(spor) for sporulation phase and total heat effects QT are calculated. Sm(3+) ion has promoting action on the growth of B. thuringiensis cry II in its lower concentration range; on the other hand, this ion has inhibitory action on the sporulation of B. thuringiensis in its higher concentration range. We also found that the effects of Sm(3+) ion on B. thuringiensis during the sporulation phase were far greater than that during the bacterial phase. It is concluded that the application of B. thuringiensis for controlling insecticides is not affected by the presence of the rare-earth elements in the environmental ecosystem.

The process that T4 phages multiply in host cells of Escherichia coli B was determined using LKB-2277 Bioactivity Monitor by means of stopped-flow method, and the growth was measured turbidometrically at the same time at 37 degrees C. By analyzing thermo-curves, quantitative parameters could be obtained to characterize the interactions of host cells and phages. The parameters such as k(a), P(max), G etc. change regularly with the decrease of multiplicity of infection (MOI) value. Infection-lysis equations were fitted and the lytic rate constant k(L) was obtained. The results show that the metabolic activity of infected cells is more intensive than that of normal cells. The phenomenon of lysis inhibition (LIN) was first detected with the microcalorimetric method, and the mechanism is discussed.

Rare earth elements have been emitted into the environment largely as fertilizer components. This has caused much fear about whether they would influence our environment, especially on the metabolism and genetics of microorganisms. In this article, the trivalent ion of a rare earth element, lanthanum, was studied for the effects on growth, transformation, and gene expression of Escherichia coli. The results showed that La3+ at concentrations from 50 to 150 microg/mL stimulated the endogenic metabolism and ectogenic metabolism, but had few effects on gene expression. La3+ at lower concentrations from 0.5 to 30 microg/mL inhibit intensively E. coli-absorbing external DNA, decreasing the transformation efficiency. It is also supported by observations using transmission electron microscopy. Our results are significant in understanding the function of rare earth elements to microorganisms and assessing the risk of application of rare earth compounds.

A series of microcalorimetric experiments were performed to investigate the effect of La(3+) on the formation of the competent state of Escherichia coli HB101 by using a LKB-2277 BioActivity Monitor at 37 C. The thermogenic curves in the absence and in the presence of La(3+) were obtained. Based on these curves, we calculated that the total heat effects (Q(T)) and the maximal power (P(max)) in the presence and absence of La(3+). Our experiments indicate that the total heat effects in the presence of a low concentration of La(3+) (

A microcalorimetric technique based on bacterial heat output was used to evaluate the action of Ce(III) ions on the growth of Escherichia coli. The power-time curves of the growth metabolism of the bacteria were studied in the presence and absence of Ce(III) by means of a LKB-2277 Bioactivity Monitor, by a stopped-flow method at 37 degrees C. For evaluation of the results, the maximum power, Pmax, the growth rate constant k, and the heat effects Qlog, Qstat, and Qtot for the log phase, the stationary phase, and total heat output, respectively, were determined. For comparison, a spectrophotometer was used to estimate the number of cells in the liquid culture. The shape of the bacteria was examined by electron microscopy. We concluded that the presence of cerium ions at concentrations below 350 microg/mL have a stimulatory effect on the growth of E. coli, whereas concentrations at or above 400 microg/mL may have an inhibitory effect.