Effect of temperature on synthesis of clavulanic acid and impurity substance G during fermentation by Streptomyces clavuligerus.

Effect of temperature on synthesis of Clavulanic acid (CA) and impurity substance G during fermentation by Streptomyces clavuligerus were investigated. Results show that fermentation at 24 °C is the most favorable for CA synthesis though the fermentation duration was 20-30 hours longer than fermentation at 26 and 28 °C. Meanwhile, the impurity substance G was only 110 mg/L in the end broth of fermentation at 24 °C, which was significantly lower than 148 and 180 mg/L of fermentation at 26 and 28 °C, respectively. Correlation of specific growth rate and CA synthesis was statistically analyzed based on data of 10 batches of industrial fermentation. Two temperature-shift strategies were investigated in 50 L fermenter. Fermentation with 26-24 °C temperature strategy achieved 5097 mg/L CA titer, meanwhile the fermentation duration was shortened 24 hours comparing with fermentation at constant 24 °C. Fermentation with 26-24 °C control strategy was validated in a 60 m3 industrial fermenter, in which 4960 mg/L of CA was achieved while impurity G substance was decreased to titer 65 mg/L from 200 to 300 mg/L of normal production.

Added value of contrast-enhanced ultrasound (CEUS) in the diagnosis of primary retroperitoneal serous adenocarcinoma: a case report.

BACKGROUND: Primary retroperitoneal serous adenocarcinoma (PRSA) is a rare malignant disease. Given the rarity of the disease, the imaging features of PRSA are unclear. Contrast-enhanced ultrasound (CEUS) also plays an important role in the evaluation of the differential diagnosis of retroperitoneal lesions. CASE PRESENTATION: We report the case of a 62-year-old woman of with increased CA125 levels for 1 year who was referred to our hospital. After conducting contrast-enhanced computed tomography and magnetic resonance imaging, the mass was misdiagnosed as a chocolate cyst. After transvaginal ultrasound (TUS) combined with CEUS, cystadenocarcinoma was considered as the initial diagnosis. Pathology results confirmed PRSA as the final diagnosis. CONCLUSIONS: CEUS features of PRSA are reported for the first time based on this case, potentially aiding in the differential diagnosis of this rare entity before surgery.

Percutaneous liver biopsy: retrospective study of primary and secondary hepatic lymphoma in twenty-one patients.

BACKGROUND: Hepatic lymphoma (HL) is categorized as primary and secondary hepatic lymphoma (PHL and SHL). This disorder can present as hepatic mass or mass-like lesion. Chemotherapy often is the first line treatment for patients with HL. Thus, an accurate pre-management histological diagnosis is essential to potentially improve clinical outcomes. The present study was to explore the prevalence of HL in ultrasound guided liver biopsies for hepatic mass or mass-like lesions, to investigate HL associated clinicopathological features, to raise the awareness of early recognition and proper diagnosis of this entity, and to assess specimen adequacy in needle core biopsy. METHODS: Twenty-one cases of HL were enrolled. Clinical and pathological characteristics were evaluated, quality of biopsies was assessed and pertinent literature was reviewed. RESULTS: HL was diagnosed in 0.94% of 2242 liver biopsy cases with ambiguous clinical presentation, laboratory tests and image studies. There were two cases of PHL (0.09%), and nineteen cases of SHL (0.85%). Histopathologically, diffuse large B-cell lymphoma was the most common type, followed by B-cell lymphoma not otherwise specified, T-cell lymphoma, Hodgkin's lymphoma, and B-cell chronic lymphocytic leukemia/small lymphocytic lymphoma. Additionally, three lymphocytic infiltration patterns were documented microscopically. The nodular infiltration was the most common type. CONCLUSIONS: HL is a rare entity and histopathology along with ancillary tests remains the only way to make the diagnosis. Clinicians' awareness of this entity and early liver biopsy are essential in patient management.

Direct electron transfer of glucose oxidase-boron doped diamond interface: a new solution for a classical problem.

A planar boron-doped diamond (BDD) electrode was treated with KOH and functionalized with 3-aminopropyltriethoxysilane (APTES) to serve as a biosensing platform for biomolecule immobilization with glucose oxidase (GOx) as a test model. The free amino groups of GOx and APTES were cross-linked by glutaraldehyde (X), a bifunctional chemical to form a stable enzyme layer (GOx-X-APTES) on BDD. Micrographs obtained by scanning electron microscopy revealed that a mesoporous structure uniformly covered the BDD surface. Cyclic voltammetry of GOx immobilized showed a pair of well-defined redox peaks in neutral phosphate buffer solution, corresponding to the direct electron transfer of GOx. The apparent heterogeneous electron transfer rate constant of the immobilized GOx was estimated to be 8.85 ± 0.47 s(-1), considerably higher than the literature reported values. The determination of glucose was carried out by amperometry at -0.40 V, and the developed biosensor showed good reproducibility and stability with a detection limit of 20 µM. Both ascorbic and uric acids at normal physiological conditions did not provoke any signals. The dynamic range of glucose detection was further extended by covering the enzyme electrode with a thin Nafion layer. The Nafion/GOx-X-APTES/BDD biosensor showed excellent stability, a detection limit of 30 µM, a linear range between 35 µM and 8 mM, and a dynamic range up to 14 mM. Such analytical performances were compared favorably with other complicated sensing schemes using nanomaterials, redox polymers, and nanowires. The APTES-functionalized BDD could be easily extended to immobilize other redox enzymes or proteins of interests.

Self-assembly of a thin highly reduced graphene oxide film and its high electrocatalytic activity.

A thin highly reduced graphene oxide (rGO) film was self-assembled at the dimethyl formamide (DMF)-air interface through evaporation-induced water-assisted thin film formation at the pentane-DMF interface, followed by complete evaporation of pentane. The thin film was transferred onto various solid substrates for film characterization and electrochemical sensing. UV-visible spectrometry, scanning electron microscopy (SEM), atomic force microscopy (AFM) and electrochemistry techniques were used to characterize the film. An rGO film showing 82.8% of the transmittance at 550 nm corresponds to a few layers of rGO nanosheets. The rGO nanosheets cross-stack with each other, lying approximately in the plane of the film. An rGO film collected on a glassy carbon (GC) electrode exhibited improved electrical conductivity compared to GC, with the electrode charge-transfer resistance (Rct) reduced from 31 Ω to 22 Ω. The as-formed rGO/GC electrode was mechanically very stable, exhibiting significantly enhanced electrocatalytic activity to H(2)O(2) and dopamine. Multiple layers of the rGO films on the GC electrode showed even stronger electrocatalytic activity to dopamine than that of the single rGO film layer. The controllable formation of a stable rGO film on various solid substrates has potential applications for nanoelectronics and sensors/biosensors.

Soil nutrient limitation and natural enemies promote the establishment of alien species in native communities.

The invasion of alien plant species threatens the composition and diversity of native communities. However, the invasiveness of alien plants and the resilience of native communities are dependent on the interactions between biotic and abiotic factors, such as natural enemies and nutrient availability. In our study, we simulated the invasion of nine invasive plant species into native plant communities using two levels of nutrient availability and suppression of natural enemies. We evaluated the effect of biotic and abiotic factors on the response of alien target species and the resistance of native communities to invasion. The results showed that the presence of enemies (enemy release) increased the biomass proportion of alien plants while decreasing that of native communities in the absence of nutrient addition. Furthermore, we also found that the negative effect of enemy suppression on the evenness of the native community and the root-to-shoot ratio of alien target species was greatest under nutrient addition. Therefore, nutrient-poor and natural enemies might promote the invasive success of alien species in native communities, whereas nutrient addition and enemy suppression can better enhance the resistance of native plant communities to invasion.

Clonal integration and phosphorus management under light heterogeneity facilitate the growth and diversity of understory vegetation and soil fungal communities.

The spatial heterogeneity of light and nutrient deficiency occurs in many forest understories. Proper fertilization management of unhealthy forests can benefit forest understory diversity and improve the stability of degraded soil; and clonal integration is a major advantage of resource sharing for many forest understory vegetation, such as pteridophytes. In this study, we tested whether understory soil fertilization and clonal integration under light heterogeneity were able to increase the performance and diversity of understory vegetation and soil microbial communities in nature. Field experiments-with or without phosphorus (P) addition, with intact or severed rhizome, and under homogeneous or heterogeneous light environments-were conducted in the understory of a typical evergreen forest in southeast China. Light heterogeneity, P addition and clonal integration promoted the growth, diversity and evenness of ferns and soil microbial biomass C, N and P (MBC, MBN and MBP) at both experimental plot and patch level. They also increased Chao1 richness and Shannon diversity of soil fungal communities at patch level, especially in the high light patches with P addition. The positive effects of P addition and clonal integration on the growth and diversity of ferns and soil microbial biomass were greatly increased under heterogeneous light. The positive effects of clonal integration on the growth were the greatest in the heterogeneous high light patches. Moreover, the interactive effect of P addition and clonal integration increased soil MBN and MBP. Clonal integration promoted the increased growth and diversity of ferns and soil MBC in the heterogeneous light environment (9.35%-35.19%), and enhanced soil MBN and MBP in the P addition treatment (9.03%-12.96%). The interactive effect of P addition and clonal integration largely led to the transition of fungal groups from slow-growing oligotrophic types to fast-growing copiotrophic types. Our results show that the interactions between clonal integration and/or P addition under light heterogeneity increase the benefits of ferns in light-rich patches, and further promote integrative performance of ferns and soil microbial communities.

[Comparison between analysis of HER2 gene and chromosome 17 in breast cancer by dual-probe chromogenic in situ hybridization and fluorescence in situ hybridization].

OBJECTIVE: To evaluate the application of dual-probe chromogenic in situ hybridization (dual-probe CISH) in analysis of HER2 gene status of breast cancer patients by comparison with fluorescence in situ hybridization (FISH). The potential impact of chromosome 17 polysomy in the determination of HER2 status was also studied. METHODS: One hundred and forty-six cases of paraffin-embedded breast cancer tissues were retrieved. Analysis of HER2 gene and chromosome 17 copy numbers using CE-approved commercial kits of dual-probe FISH (for 146 cases) and dual-probe CISH (for 73 cases) were carried out. The results were interpreted according to ASCO/CAP, 2007 either HER2 gene copy number or the ratio of HER2/centromere 17 (CEN17). RESULTS: Of the 73 cases analyzed by both FISH and dual-probe CISH, the concordance rates for negative and positive results was 91.7% (33/36) and 97.4% (37/38) respectively, while the overall concordance rate between the two methods was 95.9% (70/73). Of the 146 cases analyzed by FISH, 13 cases were interpreted as equivocal if only HER2 copies were counted, compared with 8 equivocal cases by calculating the ratio of HER2/CEN 17. Moreover, 3 cases (4.8%) of the 63 HER2-positive cases determined by HER2 copies turned out to be HER2-negative when determined by the ratio of HER2/CEN 17; while using dual-probe CISH, 1 (3.0%) of the 33 positive cases turned out to be negative. In addition, when using FISH, there were more chromosome 17 polysomy cases (63.5%, 40/63) in the HER2-positive subgroup than HER2-negative subgroup (37.3%, 28/75) (P = 0.002). CONCLUSIONS: Dual-probe CISH can achieve similar results as compared to FISH, indicating that this technology is a reliable alternative to FISH in HER2 testing. The accuracy can further be improved when HER2 and chromosome 17 are simultaneously tested and counted.