蒙古栎次生林群落结构及优势种群点格局分析

为探求大小兴安岭过渡区物种共存、生物多样性保护与维持机制,以黑龙江中央站黑嘴松鸡国家级自然保护区蒙古栎天然次生林25 hm²固定样地调查数据为基础,从群落物种组成、结构特征、径级结构以及优势种群的空间点格局分析对该样地进行分析。结果表明：样地内共有胸径≥1 cm的维管植物10种,活立木共 34 778株,平均密度1 392株·hm^-2。其中,重要值大于10%的物种共计4种,依次为蒙古栎（Quercus mongolica Fisch.ex Ledeb.）、黑桦（Betula dahurica Pall.）、白桦（Betula platyphylla Suk.）、兴安落叶松（Larix gmelinii（Rupr.）Kuzen）,占全样地的89.65%。该样地的Shannon-Wiener多样性H′、Simpson多样性D、Pielou均匀度指数J分别为1.577、0.760、0.685。表明该群落稀有物种较少,常见种比例较大,群落结构较为简单。样地内所有树种平均胸径10.77 cm。群落内总径级分布呈“倒J型”,符合典型异龄林的分布特征。黑桦、白桦径级分布近似“倒J型”,属于增长种群,蒙古栎种群径级结构为双峰型。兴安落叶松种群径级近似正态分布,有随演替进行逐渐消失的趋势,属于该群落的衰退种。在CSR模型下,4种优势种群的空间格局主要表现为聚集分布,且聚集程度随尺度增加聚集程度减弱,最终呈现随机或均匀分布趋势。在NS模型下,除兴安落叶松外,其余3种植株在小尺度（0~5 m）表现聚集性,可能是受种子的扩散限制的影响。对比4种优势种群,聚集强度表现为黑桦＞白桦＞蒙古栎＞兴安落叶松,因此我们推断群落内不同种群的聚集强度不仅与研究尺度相关,与种群的多度也存在一定的相关关系。     

环状RNA Circ_0001073在恶性黑素瘤中的表达及其对A375细胞恶性表型的影响

目的:通过检测环状RNA Circ_0001073在恶性黑素瘤细胞与正常表皮黑素细胞中的表达差异,及其对恶性黑素瘤A375细胞恶性表型的影响,阐明Circ_001073在恶性黑素瘤细胞中的表达及功能。方法:采用聚合酶链式反应(Real-time quantitative polymerase chain reaction, RT-QPCR)方法检测正常表皮黑素细胞和恶性黑素瘤细胞中Circ_0001073的表达水平;应用小干扰RNAs沉默恶性黑素瘤A375细胞中Circ_0001073表达,5-乙炔基-2'-脱氧尿苷(5-Ethynyl-2'-deoxyuridine,EdU)实验检测沉默Circ_0001073对A375细胞增殖的影响,平板克隆实验检测沉默Circ_0001073对A375细胞克隆形成的影响,细胞划痕实验评估沉默Circ_0001073对A375细胞迁移能力的影响,Transwell实验评估沉默Circ_0001073对A375细胞侵袭能力的影响。结果:qRT-PCR结果显示Circ_0001073在恶性黑素瘤细胞中的表达低于正常表皮黑素HEMa-LP细胞(P0.05)。应用Circ_0001073si RNA转染A375细胞后,Circ_0001073的表达水平较转染Circ_0001073 NC的细胞显著降低(P0.05)。EdU实验结果显示:沉默A375细胞中Circ_0001073的表达后,A375细胞增殖能力显著增强(P0.05);平板克隆实验结果显示:沉默A375细胞中Circ_0001073的表达后,A375细胞克隆形成能力显著增强(P0.05);细胞划痕实验结果显示:沉默A375细胞中Circ_0001073的表达后,细胞迁移能力显著增强(P0.05);Transwell实验结果显示:沉默A375细胞中Circ_0001073的表达后,细胞侵袭能力显著增强(P0.05)。结论:Circ_0001073在恶性黑素瘤细胞中低表达,并可抑制A375细胞的增殖、克隆形成、迁移及侵袭。     

Hygropreference behaviour and humidity detection in the yellow‐spined bamboo locust,Ceracris kiangsu

Water is a critical resource for all terrestrial insects. The yellow‐spined bamboo locust Ceracris kiangsu Tsai (Oedipodidae: Orthoptera), matures, copulates and reproduces in the summer and adults are observed mud‐puddling in human urine‐contaminated materials on hot days. Besides obtaining NaCl and NH₄HCO₃, the locust may also compensate for water deficiency. In a dual‐choice test in the laboratory, adults prefer to remain on wet rather than dry filter paper at high temperature (36 °C). The females are more likely to move towards and stay on wet filter paper than males. The adults chew wet filter paper in the laboratory at higher temperature and the females consume more than the males. Moreover, foam plastic containing an aqueous solution of an insecticide, bisultap, results in greater mortality in females than a dry formulation, both in the laboratory and the field. The water content of the frass from males is significantly lower than that from females and may partially explain the stronger hygropreference behaviour in females. Other possible reasons for sexually different hygropreference are also discussed. The removal of the adult antennae substantially reduces discrimination between wet and dry filter paper and mortality resulting from wet bisultap formulations in the laboratory. Hence, antennae mediate, at least partially, hygropreference behaviour.     

Microbial deterioration of gelatin emulsion photographs: Differences of susceptibility between black and white and colour materials

Microbial deterioration is a common problem in photographic collections, and has been considered a major cause of deterioration. However, few studies have been carried out on this topic, and most of the literature concerns biodeterioration of archival documents in general, including both micro- and macroorganisms. There have been no detailed studies on the interactions between microorganisms, environment, and the composition of photographic material. This study focuses on fungal deterioration of gelatin emulsion photographs. It was part of a study of three collections in Lisbon, Portugal. The first part is quantitative research on the fungal contamination of the Horácio Novais collection, and the second involves induced contamination of experiments on gelatin emulsion photographs. At the end these data are analysed, taking into account the hypothesis that colour materials are more susceptible to fungal deterioration than are black and white ones. This hypothesis is based on the observations of professionals working with photograph collections who report that, at least in plastic base supports (negatives and slides), colour materials are frequently more contaminated than the black and white ones. An overall look at the results seems to indicate a higher susceptibility of the colour chromogenic photographic materials to fungal colonization compared to the black and white materials. However, this hypothesis could not be absolutely confirmed by this study.     

Anatomical development of the pericarp and seed of Oncidium flexuosum Sims (ORCHIDACEAE)

Interpretation of the anatomical structure of the ovary and fruit of the Orchidaceae family is still controversial, which makes it difficult to understand the development and dehiscence of the fruit. The genus Oncidium is polyphyletic and is currently the subject of taxonomic studies. In this study, we have investigated the anatomical development of the pericarp and seed of Oncidium flexuosum Sims to determine important diagnostic characters that, along with molecular data, can assist in defining this group. We have found a new anatomical characteristic of the family: the presence of precursor cells for fruit dehiscence, which were visible from the beginning of development and located on the outer walls of the sterile valves. In contrast with what has been observed by different authors with other species, in the mature fruit of O. flexuosum, only the endocarp of the fertile valves and a few cells near the exocarp and the vascular bundle in the sterile valves show parietal thickening, while the rest remains parenchymatous. During the development of the ovule and embryo, we have shown that the embryonic sac of this species has eight nuclei and that the embryo has a long and elaborate suspensor.     

Hesperidin,a Flavone Glycoside,as Mediator of Neuronal Survival

Flavonoids comprise the most common group of plant polyphenols and provide much of the flavor and color to fruits and vegetables. More than 5,000 different flavonoids have been described. The biological activities of flavonoids cover a very broad spectrum, from anticancer and antibacterial activities to inhibition of bone reabsorption and neuroprotection effect. Although emerging evidence suggests that flavonoids have an important role on brain development, little is known about their mechanisms of action. In the present work, we performed a screening of flavonoid actions by analyzing the effects of these substances (hesperidin and rutin) on neural progenitors and neuronal morphogenesis in vitro. We demonstrated that treatment of neural progenitors with the flavonoid hesperidin enhanced neuronal population as revealed by an 80% increase in the number of β-tubulin III cells. This effect was mainly due to modulation of neuronal progenitor survival. Pools of astrocyte and oligodendrocyte progenitors were not affected by hesperidin whereas rutin had no effect on neuronal population. We also demonstrated that the flavonoid hesperidin modulates neuronal cell death by activating MAPK and PI3K pathways. This opens the possibility of using flavonoids for potential new therapeutic strategies for neurodegenerative diseases.     

Anaerobic digestion challenge of raw olive mill wastewater

Olive mill wastewater (OMW) was digested in its original composition (100% v/v) in an anaerobic hybrid. High concentrations (54–55 kg COD m⁻³), acid pH (5.0) and lack of alkalinity and nitrogen are some OMW adverse characteristics. Loads of 8 kg COD m⁻³ d⁻¹ provided 3.7–3.8 m³ biogas m⁻³ d⁻¹ (63–64% CH₄) and 81–82% COD removal. An effluent with basic pH (8.1) and high alkalinity was obtained. A good performance was also observed with weekly load shocks (2.7–4.1, 8.4–10.4 kg COD m⁻³ d⁻¹) by introducing piggery effluent and OMW alternately. Biogas of 3.0–3.4 m³ m⁻³ d⁻¹ (63–69% CH₄) was reached.Developed biomass (350 days) was neither affected by raw OMW nor by organic shocks. Through the effluents complementarity concept, a stable process able of degrading the original OMW alone was obtained. Unlike what is referred, OMW is an energy resource through anaerobiosis without additional expenses to correct it or decrease its concentration/toxicity.     

M-26碱性木聚糖酶的分离纯化及酶学性质研究

从Bacillus pumilus M-26发酵液中分离纯化碱性木聚糖酶,进行酶学性质研究,同时制备工业用碱性木聚糖酶制剂。首先将M-26发酵液进行硫酸铵盐析,制备工业用碱性木聚糖酶干品;然后进行sephadexG-25层析脱盐和cellulose DE-52层析得以纯化。硫酸铵的饱和度50%,酶制剂的酶活可达9 000 IU/g,收率为85%;分离纯化使酶的比活为126.32 IU/mg蛋白,纯化倍数为19.89,酶的回收率12.83%;分子量约为20 ku;M-26碱性木聚糖酶的最适温度和pH分别是55℃和pH 8.0,具有一定的耐碱性;该酶无纤维素酶活性,Fe2＋对其有激活作用;Mn2＋、Zn2＋、Fe3＋、Cu2＋对其具有抑制作用。短小芽胞杆菌M-26碱性木聚糖酶具有纸浆生物漂白应用前景。     

Influence of induction conditions on the expression of carbazole dioxygenase components (CarAa, CarAc, and CarAd) from Pseudomonas stutzeri in recombinant Escherichia coli using experimental design

Carbazole 1,9a-dioxygenase (CarA), the first enzyme in the carbazole degradation pathway used by Pseudomonas sp., was expressed in E. coli under different conditions defined by experimental design. This enzyme depends on the coexistence of three components containing [2Fe-2S] clusters: CarAa, CarAc, and CarAd. The catalytic site is present in CarAa. The genes corresponding to components of carbazole 1,9a-dioxygenase from P. stutzeri were cloned and expressed by salt induction in E. coli BL21-SI (a host that allows the enhancement of overexpressed proteins in the soluble fraction), using the vector pDEST?14. The expression of these proteins was performed under different induction conditions (cell concentration, temperature, and time), with the help of two-level factorial design. Cell concentration at induction (measured by absorbance at 600 nm) was tested at 0.5 and 0.8. After salt induction, expression was performed at 30 and 37°C, for 4 h and 24 h. Protein expression was evaluated by densitometry analysis. Expression of CarAa was enhanced by induction at a lower cell concentration and temperature and over a longer time, according to the analysis of the experimental design results. The results were validated at Abs (ind) = 0.3, 25°C, and 24 h, at which CarAa expression was three times higher than under the standard condition. The behavior of CarAc and CarAd was the inverse, with the best co-expression condition tested being the standard one (Abs (ind) = 0.5, T = 37°C, and t = 4 h). The functionality of the proteins expressed in E. coli was confirmed by the degradation of 20 ppm carbazole.