樟树叶片挥发性有机物释放季节动态和日动态变化规律

采用动态顶空采集法和热脱附-气质联用技术,对不同季节和一天内不同时间点樟树叶片释放的挥发性有机物(VOCs)成分含量及其变化规律进行了分析。结果表明:全年樟树叶片释放的VOCs共计78种,其中萜烯类(19种)和烷烃类(18种)化合物种类较多; 32种樟树叶片释放的挥发性成分相对含量在不同季节存在显著差异(P<0.05); 3月份释放的VOCs种类最为丰富,萜烯类化合物相对含量最高(43.49%),主要为1-石竹烯、D-柠檬烯和α-蒎烯,其他月份释放的VOCs则以烷烃类和醇类为主;春季,樟树叶片在绝大多数时间点释放VOCs以萜烯类化合物为主,且早上8:00释放的萜烯类化合物相对含量最大。综上结果认为,樟树是营造保健型生态园林的理想树种,其叶片释放的VOCs中富含多种对人体健康有益的萜烯类化合物,春季的早晨是进行森林康养活动的最佳时间。     

燃烧植物产生烟与热的生理生态效应

燃烧植物产生的烟与热对植物的生理生态功能有重要的影响,相关研究已成为生态学研究的热点之一。植物源烟对一些植物种子的萌发和幼苗生长有促进作用,这种促进作用与GA和细胞分裂素的作用相似。在植物烟水溶液中分离得到了具有促进植物种子萌发作用的化合物丁烯羟酸内酯,该物质具有热稳定性、挥发性和有效浓度范围广等特点。丁烯羟酸内酯可以通过纤维素加热产生,因而几乎所有的植物燃烧产生的烟中都可以产生丁烯羟酸内酯。热因子对植物种子萌发有利作用表现为打破种子休眠、清除限制种子萌发的物理、化学因素和减轻种子病原体等方面。大量研究显示,不同植物对烟与热的响应机理存在显著的差异,这是植物群落过火后物种组成改变的重要原因之一。烟与热因子对植物生理生态作用的研究我国开展较少．这与我国是一个森林、草原火灾频繁的国家是不相称的,加强这方面的研究很有必要。另外,今后我国可以在烟与热因子对植物作用的机理,揭示传统用烟火处理土壤促进农林业植物生长的物理和化学本质,以及这些机理在发展有机农业中运用等方面开展深入的研究。     

Phytogenic compounds from avocado (Persea americana L.) extracts; antioxidant activity,amylase inhibitory activity,therapeutic potential of type 2 diabetes

Diabetes is a worldwide public health disease. Currently, the most effective way to treat diabetes is to mitigate postprandial hyperglycemia by inhibiting carbohydrate hydrolysis enzymes in the digestive system. Plant extracts are rich in bioactive compounds, which can be used in diabetes treatment. This study aims to evaluate the polyphenols content in ethanolic extracts of avocado fruit and leaves (Persea americana Mill.). Additionally, their antioxidant activity using DPPH, while the inhibition ability of α-amylase was examined by reacting different amounts of the extracts with α-amylase compared to acarbose as standard inhibitor. The active compounds were detected in the extracts by LC/MS. The obtained results showed that the leaf extract recorded a significant content of total phenolic compounds compared to the fruit extract (178.95 and 145.7 mg GAE /g dry weight, respectively). The total flavonoid values ??ranged from 32.5 to 70.08 mg QE/g dry weight of fruit and leaves extracts, respectively. Twenty-six phytogenic compounds were detected in leaf and fruit extract by LC/MS. These compounds belong to fatty acids, sterols, triterpenes, phenolic acids, and flavonoids. The antioxidant activity of the extracts is due to the exist of phytogenic compounds, i.e., polyphenols and flavonoids. The antioxidant activity increased in a concentration dependant manner. Avocado fruit extract (1000 µg/mL) scavenged 95% of DPP? while leaf extract rummaged 91.03% of free radicals compared with Vit C and BHT. Additionally, higher α-amylase inhibitory activity was observed in fruit extract than the leaf extract, where the fruit and leaf extract (1000 μg/ml) inhibited the enzyme by 92.13% and 88.95%, respectively. The obtained results showed that the ethanolic extracts of avocado could have a significant impact on human health due to their high content of polyphenols.     

Desert soil fungi isolated from Saudi Arabia: cultivable fungal community and biochemical production

Desert soils harbor fungi that have survived under highly stressed conditions of high temperature and little available moisture. This study was designed to survey the communities of cultivable fungi in the desert soils of the Arabian Peninsula and to screen the fungi for the potentially valuable antioxidants (flavonoids, phenols, saponins, steroids, tannins, terpenoids, and alkaloids) and enzymes (cellulase, laccase, lipase, protease, amylase, and chitinase). Desert soil was sampled at 30 localities representing different areas of Saudi Arabia and studied for physico-chemical soil properties. Five types of soil texture (sand, loamy sand, sandy loam, silty loam, and sandy clay loam) were observed. A total of 25 saprotrophic species was identified molecularly from 68 isolates. Our survey revealed 13 culturable fungal species that have not been reported previously from Arabian desert soils and six more species not reported from Saudi Arabian desert soils. The most commonly recorded genera were Aspergillus (isolated from 20 localities) and Penicillium (6 localities). The measurements of biochemicals revealed that antioxidants were produced by 49 and enzymes by 52 isolates; only six isolates did not produce any biochemicals. The highest biochemical activity was observed for the isolates Fusarium brachygibbosum and A. phoenicis. Other active isolates were A. proliferans and P. chrysogenum. The same species, for instance, A. niger had isolates of both high and low biochemical activities. Principal component analysis gave a tentative indication of a relationship between the biochemical activity of fungi isolated from soil and soil texture variables namely the content of silt, clay and sand. However, any generalizable relation between soil properties and fungal biochemical activities cannot be suggested. Each fungal isolate is probable to produce several antioxidants and enzymes, as shown by the correlation within the compound groups. Desert soil warrants further research as a promising source of biochemicals.     

The effects of ingesting plant hormones on schistosomiasis in mice: An experimental study

A number of studies have shown that primates monitor and select plant species in their diet as a function of their secondary compound composition. The possibility also exists that secondary compounds, when used in appropriate concentrations, may have a beneficial, medicinal aspect. In this regard, synthesis of a variety of data suggested a connection between selection of Balanites by Ethiopian baboons, and the distribution of schistosomiasis. To test the hypothesis that the secondary compounds in Balanites might be selected for ‘medicinal purposes’, we conducted an experiment on the effect of adding the active principle, diosgenin, to the food of schistosome-infected mice. The hypothesis was that this steroidal saponin might alter the host's hormonal milieu, making a less hospitable environment for the adult schistosomes. Sacrifice of the mice showed diosgenin-fed animals to have an augmented rather than decreased response to the disease. However, the data support the developing literature that shows that the host's hormonal environment has a major effect on the parasitic diseases they are subject to, and that the hormonal environment can be dramatically influenced by the secondary compounds in the diet.     

Tectona grandis L.f: A comprehensive review on its patents,chemical constituents,and biological activities

Tectona grandis L.f is a timber plant that is commonly referred to as teak. Its wide use as a medicine in the various indigenous systems makes it a plant of importance. A wide gamut of phytoconstituents like alkaloids, phenolic glycosides, steroids, etc. has been reported. A renewed interest in this plant has resulted in scientific investigations by various researchers towards the isolation and identification of active constituents along with scientific proof of its biological activities. The different parts of the plant have been scientifically evaluated for their antioxidant, antipyretic, analgesic, hypoglycemic, wound healing, cytotoxic, and many more biological activities. Documentation of this scientific knowledge is of importance to have consolidated precise information encompassing the various aspects of this plant, which could provide a base for future studies. This review is a compilation of the salient reports on these investigations concerning phytochemistry, the methods used to identify and quantify the constituents, the evaluation methods of the biological activity, toxicological studies, allergies and the patent/patent applications. This will further help researchers to find an area of the gap for future studies.     

Topoisomerase II poisoning by indazole and imidazole complexes of ruthenium

Trans-imidazolium (bis imidazole) tetrachloro ruthenate (RuIm) and trans-indazolium (bis indazole) tetrachloro ruthenate (RuInd) are ruthenium coordination complexes, which were first synthesized and exploited for their anticancer activity. These molecules constitute two of the few most effective anticancer ruthenium compounds. The clinical use of these compounds however was hindered due to toxic side effects on the human body. Our present study on topoisomerase II poisoning by these compounds shows that they effectively poison the activity of topoisomerase II by forming a ternary cleavage complex of DNA, drug and topoisomerase II. The thymidine incorporation assays show that the inhibition of cancer cell proliferation correlates with topoisomerase II poisoning. The present study on topoisomerase II poisoning by these two compounds opens a new avenue for renewing further research on these compounds. This is because they could be effective lead candidates for the development of more potent and less toxic ruthenium containing topoisomerase II poisons. Specificity of action on this molecular target may reduce the toxic effects of these ruthenium-containing molecules and thus improve their therapeutic index.     

合成生物制造2022

本文对2022年《生物工程学报》发表的与合成生物制造相关的综述和研究论文进行了评述,重点讨论了DNA测序、DNA合成、DNA编辑、基因表达调控和数学细胞模型等底层技术,酶的设计、改造和应用技术,化学品生物催化、氨基酸及其衍生物、有机酸、天然化合物、抗生素与活性肽、功能多糖、功能蛋白质等重要产品的生物制造技术,一碳化合物和生物质原料利用技术以及合成微生物组技术,以帮助读者从一个侧面了解合成生物制造相关技术和产业的发展情况。     

块菌发育过程中伴生微生物多样性及其生态功能

块菌属Tuber是子囊菌门中一类珍贵的地下生外生菌根真菌,能与松科、壳斗科等多种树木形成菌根共生关系,在森林生态系统中扮演着重要的角色。同时,该属的一些种类因其独特的香味而备受国际食用菌市场推崇,具有极高的经济价值。在块菌属漫长的生活史中,菌丝的生长、菌根的形成、子囊果的产生和发育、特殊芳香化合物及活性物质的产生和积累均与其伴生微生物有着密切的关系。近年来,分子生物学技术的发展尤其是高通量测序技术的应用推动了对块菌属子囊果形成和发育机制的研究,为块菌生态学研究提供了有力的工具,使块菌伴生微生物相关研究取得重要突破。本文综述了近5年来国内外对块菌属生长发育过程中伴生细菌、真菌多样性及其生态功能的相关研究,并探讨了其中尚未清楚的问题及今后可能的研究方向,为块菌属生物学的研究及人工栽培奠定基础。