The parasitic and lethal effects of Trichoderma longibrachiatum against Heterodera avenae

Heterodera avenae is a devastating plant pathogen that causes significant yield losses in many crops, but there is a lack of scientific information whether this pathogen can be controlled effectively using biocontrol agents. Here we determined the parasitic and lethal effects of Trichoderma longibrachiatum against H. avenae and the possible mechanism involved in this action. Both in vitro and greenhouse experiments were conducted. In vitro, T. longibrachiatum at the concentrations of 1.5 × 10⁴ to 1.5 × 10⁸ spores per ml had a strong parasitic and lethal effect on the cysts of H. avenae, with the concentration of 1.5 × 10⁸ spores per ml having >90% parasitism 18 days after treatments. In greenhouse, T. longibrachiatum inoculation decreased H. avenae infection in wheat (Triticum aestivum) significantly. Observations with microscopes revealed that after mutual recognition with cysts, the spore of T. longibrachiatum germinated with a large number of hyphae, and reproduced rapidly on the surface of cysts. Meanwhile, the cysts surface became uneven, with some cysts producing vacuoles, and the others splitting. Finally the cysts were dissolved by the metabolite of T. longibrachiatum. Chitinase activity increased in the culture filtrates of T. longibrachiatum and reached the maximum 4 days after inoculation in the medium supplemented with colloidal chitin (1.02 U/min per ml) and nematode cysts (0.78 U/min per ml). The parasitism and inhibition of cysts through the increased extracellular chitinase activity serves as the main mechanism with which T. longibrachiatum against H. avenae. In conclusion, T. longibrachiatum has a great potential to be used as a biocontrol agent against H. avenae.     

PET probe detecting non-small cell lung cancer susceptible to epidermal growth factor receptor tyrosine kinase inhibitor therapy

Tyrosine kinase inhibitors for epidermal growth factor receptor (EGFR-TKIs) are used as molecular targeted therapy for non-small cell lung cancer (NSCLC) patients. The therapy is applied to the patients having EGFR-primary L858R mutation, but drug tolerance caused by EGFR-secondary mutation is occurred within one and half years. For the non-invasive detection of the EGFR-TKIs treatment positive patients by positron emission tomograpy (PET) imagaing, fluorine-18 labeled thienopyrimidine derivative, [¹⁸F]FTP2 was newly synthesized. EGFR inhibition assay, cell uptake study, and blocking study indicated [¹⁸F]FTP2 binds with high and selective affinity for EGFR with L858R mutation, and not with L858R/T790M dual mutations. On animal PET study using tumor bearing mice, H3255 cells expressing L858R mutated EGFR was more clearly visualized than H1975 cells expressing L858R/T790M dual mutated EGFR. [¹⁸F]FTP2 has potential for detecting NSCLC which is susceptible to EGFR-TKI treatment.     

施肥对落叶松和水曲柳人工林土壤微生物生物量碳和氮季节变化的影响

2007-2008年,采用氯仿熏蒸浸提法测定了落叶松和水曲柳人工林土壤微生物生物量,研究施N肥对土壤微生物生物量碳、氮,以及细菌、真菌和放线菌数量季节变化的影响.结果表明：落叶松林地土壤微生物生物量碳、氮两年平均值分别比水曲柳林地低13.8%和18.3%,但两种林分土壤微生物生物量碳、氮具有相同的季节变化规律：5月最低,9月最高;表层（0～10 cm）土壤微生物生物量碳、氮及微生物数量均高于亚表层（10～20 cm）土壤.但细菌、真菌和放线菌数量的季节变化格局与生物量不同.施肥降低了两种林分的微生物生物量碳、氮,以及细菌、真菌和放线菌数量,其中,落叶松林地微生物生物量碳和氮分别降低了24%和63%,水曲柳分别降低了51%和68%.说明施N肥限制了土壤微生物生物量,改变了土壤微生物的群落结构.     

罗汉果组培繁殖的技术要点

报道罗汉果组培繁殖的各项主要技术要点,包括组培条件、培养基的配制、外植体的选取与消毒、接种与培养、种源保存、炼苗与移栽、苗木包装与运输等。提出了5种培养基参考配方,即茎段诱导培养:MS+BA0.5～1.0mg/L+IAA(NAA)0.05～0.1mg/L+白糖3%+琼脂4.5g/L,pH5.8;茎尖诱导培养:MS+BA0.5～1.0mg/L+NAA0.05～0.1mg/L+椰子水100mL+白糖3%+琼脂4.5mg/L,pH5.8;继代培养(丛生芽方式):MS+BA0.3～0.7mg/L+NAA0.05/IAA0.1mg/L+白糖3%+琼脂4.5mg/L,pH5.8;继代培养(微型扦插方式):MS+BA0.1mg/L+IAA0.3mg/L+活性炭0.07g/L+白糖3%+琼脂4.5mg/L,pH5.8;生根培养:MS+BA0.07mg/L+IBA0.15mg/L+IAA0.1mg/L+活性炭0.1g/L+白糖3%+琼脂4.5mg/L,pH5.8。分析了外植体培养过程中可能出现的不良状况的原因并提出预防措施,明确了炼苗移栽的适宜条件并制定出相应的管理方法。形成了一套较为完整的罗汉果组培苗繁殖生产技术规程。     

The Potential Value of Preoperative MRI Texture and Shape Analysis in Grading Meningiomas: A Preliminary Investigation

OBJECT: Preoperative knowledge of meningioma grade is essential for planning treatment and surgery. The purpose of this study was to investigate the diagnostic value of MRI texture and shape analysis in grading meningiomas. METHODS: A surgical database was reviewed to identify meningioma patients who had undergone tumor resection between January 2015 and December 2016. Preoperative MR images were retrieved and analyzed. Texture and shape analysis was conducted to quantitatively evaluate tumor heterogeneity and morphology. Three machine learning classifiers were trained with these features to build classification models. The performance of the features and classification models was assessed. RESULTS: A total of 131 patients were included in this study: 21 with high-grade meningiomas and 110 with low-grade meningiomas. Three texture features were selected: Horzl_RLNonUni, S(2,2)SumOfSqs, and WavEnHL_s-3; three shape features were selected: GeoFv, GeoW4, and GeoW5b. The Mann–Whitney test indicated that all six features were significantly different between high-grade and low-grade meningiomas. AUC values were generally greater than 0.50 (range, 0.73 to 0.88). Sensitivities and specificities ranged from 47.62% to 90.48% and 69.09% to 96.36%, respectively. Among the nine classification models obtained, the one built by training the SVM classifier with all six features achieved the best performance, with a sensitivity, specificity, diagnostic accuracy, and AUC of 0.86, 0.87, 0.87, and 0.87, respectively. CONCLUSIONS: Texture and shape analysis, especially when combined with a SVM classifier, can provide satisfactory performance in the preoperative determination of meningioma grade and is thus potentially useful for clinical application.     

Rhodobacteraceae on the marine brown alga Fucus spiralis are abundant and show physiological adaptation to an epiphytic lifestyle

Macroalgae harbour specific microbial communities on their surface that have functions related to host health and defence. In this study, the bacterial biofilm of the marine brown alga Fucus spiralis was investigated using 16S rRNA gene amplicon-based analysis and isolation of bacteria. Rhodobacteraceae (Alphaproteobacteria) were the predominant family constituting 23% of the epibacterial community. At the genus level, Sulfitobacter, Loktanella, Octadecabacter and a previously undescribed cluster were most abundant, and together they comprised 89% of the Rhodobacteraceae. Supported by a specific PCR approach, 23 different Rhodobacteraceae-affiliated strains were isolated from the surface of F. spiralis, which belonged to 12 established and three new genera. For seven strains, closely related sequences were detected in the 16S rRNA gene dataset. Growth experiments with substrates known to be produced by Fucus spp. showed that all of them were consumed by at least three strains, and vitamin B₁₂ was produced by 70% of the isolates. Since growth of F. spiralis depends on B₁₂ supplementation, bacteria may provide the alga with this vitamin. Most strains produced siderophores, which can enhance algal growth under iron-deficient conditions. Inhibiting properties against other bacteria were only observed when F. spiralis material was present in the medium. Thus, the physiological properties of the isolates indicated adaption to an epiphytic lifestyle.     

The Effects of Root Treatment with Various Stress Agents on Plant Cold- and Heat-Tolerance

The root systems of cucumber (Cucumis sativus L.), wheat (Triticum aestivum L.), and barley (Hordeum vulgare L.) plants were subjected to a short-term (6–7-h-long) treatment with low and high temperatures, sodium chloride, and lead nitrate, and the effect of these treatments on the changes in the cold- and heat-tolerance of leaf cells was determined. It was established that chilling of cucumber and wheat seedling roots at 10 and 2°C, respectively, or their heating at 38°C and 40°C, respectively, induced an increase in both cold- and heat-tolerance of leaf cells. An increase in the cold- and heat-tolerance was also observed in roots treated with sodium chloride at concentrations of 0.15 M (cucumber) and 0.2 M (wheat), as well as with lead nitrate at a concentration of 0.1 mM (barley, wheat). The tolerance increase induced by these stress agents was accompanied by a considerable increase in the ABA concentration in leaves. The effect of physical and chemical stress agents is suggested to induce the same nonspecific changes in the aboveground organs. These changes bring about, directly or indirectly, an increase in the cold- and heat-tolerance and are related to an increase in the ABA content.     

Prostaglandins and thromboxanes in amniotic fluid during rivanol-induced abortion and labour

Abortion or delivery were induced by extra-amniotic instillation of Rivanol during the second trimester in twelve patients and during the third trimester in two patients with fetal death and one patient with fetal acrania. Serial sampling of amniotic fluid was performed through a transabdominal catheter and the levels of free arachidonic acid (AA), prostaglandin F₂α (PGF₂α), prostaglandin E₂ (PGE₂), 6-keto-prostaglandin F₁α (6-keto-PGF₁α) and thromboxane B₂ (TXB₂) were determined. The levels of AA, PGF₂α, PGE₂, 6-keto-PGF₁α and TXB₂ in amniotic fluid increased significantly during induction with the exception of AA in fetal death which was high and remained constant during induction. Furthermore, PGF₂α, 6-keto-PGF₁α and TXB₂ were all significantly correlated to AA.These observations suggested that free AA is released during Rivanol-induction of abortion and labour giving an increased synthesis of PGF₂α, PGE₂ prostacyclin and thromboxane A₂ in the fetal membranes and the decidua but not in the fetus. This increase might be relevant for the initiation and progress of abortion and labour in these patients.     

Further studies on the subcellular localization of lipid-degrading enzymes

Further work on the subcellular localization of two lipid-degrading enzymes, lipolytic acyl hydrolase (LAH) and lipoxygenase (LOX) has been carried out on brassica florets, potato shoots and pea roots. In all cases, the LAH profile on sucrose and Ficoll density gradients was coincident with ‘lysosomal’ acid phosphatase activity. However, the localization of LOX activity was different for each tissue. In pea roots the activity of LOX was localized in the ‘lysosomal’ fraction, whereas with brassica florets (cauliflower and calabrese) it was present in a heavy body with a similar density to plastids and in potato shoots LOX gave only low particulate recoveries.