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The bioactivity of the aqueous extracts of the leaf and stem bark of the medicinal plant, Alstonia boonei De Wild (Apocyanaceae), against the pink stalk borer, Sesamia calamistis Hampson (Lepidoptera: Noctuidae) was studied in a laboratory bioassay. The extracts were incorporated into artificial diet at a rate of 0.0% (control), 1.0%, 2.5%, 5.0%, and 10.0% (w/w). Both extracts significantly (P<0.01) reduced larval survival and weight in a dose dependent manner. The concentrations that killed 50% of the larvae (LC50) for the stem bark extract were 2.8% and 2.1% at 10 and 20 DAI (days after introduction), respectively, while those for the leaves extract were 5.6% and 3.5%. The weights of the larvae also varied significantly (P<0.05) between the treatments in a dose dependent manner. We conclude that both leaf and stem bark extracts of A. boonei are toxic, used as growth inhibitors to S. calamistis larvae, and hold good promise for use as alternative crop protectants against S. calamistis. 相似文献
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为了筛选得到对玉米茎腐病菌室内抑制活性较高的杀菌剂,采用菌丝生长速率法测定了不同化学杀菌剂对肿囊腐霉菌（Pythium inflatum）和禾谷镰孢菌（Fusarium graminearum）2种致病菌的抑制活性。结果表明,丙森锌、雷多米尔·锰锌、烯酰吗啉和氟吡菌胺4种杀菌剂对肿囊腐霉菌的毒力较高,其EC50。分别为O．40μgZmL、0．47μg／mL、0．61μg／mL和2．64μg／mL;禾谷镰孢菌对咯菌腈、戊唑醇和多菌灵3种杀菌剂的敏感性较高,其EC50分别为0．06μg／,mL、0．32μg／mL和0．85μg／mL,苯醚甲环唑和腈菌唑2种杀菌剂对禾谷镰孢菌的抑制活性稍差,其EC50。分别为1．71μg／mL和1．80μg／mL。上述筛选到的9种药剂对玉米茎腐病菌的室内抑菌活性较高,可以作为供试药剂进行大田药效试验。 相似文献
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Political polarization remains perhaps the “greatest barrier” to effective COVID-19 pandemic mitigation measures in the United States. Social media has been implicated in fueling this polarization. In this paper, we uncover the network of COVID-19 related news sources shared to 30 politically biased and 2 neutral subcommunities on Reddit. We find, using exponential random graph modeling, that news sources associated with highly toxic – “rude, disrespectful” – content are more likely to be shared across political subreddits. We also find homophily according to toxicity levels in the network of online news sources. Our findings suggest that news sources associated with high toxicity are rewarded with prominent positions in the resultant network. The toxicity in COVID-19 discussions may fuel political polarization by denigrating ideological opponents and politicizing responses to the COVID-19 pandemic, all to the detriment of mitigation measures. Public health practitioners should monitor toxicity in public online discussions to familiarize themselves with emerging political arguments that threaten adherence to public health crises management. We also recommend, based on our findings, that social media platforms algorithmically promote neutral and scientific news sources to reduce toxic discussion in subcommunities and encourage compliance with public health recommendations in the fight against COVID-19. 相似文献
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Izatus Shima Taib Siti Balkis Budin Seri Maseran Siti Nor Ain Jamaludin Mohamed Santhana Raj Louis Srijit Das Sulaiman Sallehudin Nor Fadilah Rajab Othman Hidayatulfathi 《Journal of Zhejiang University. Science. B》2009,10(11):813-819
Litsea elliptica Blume leaves have been traditionally used as medicinal herbs because of its antimutagenicity, che-mopreventative and insecticidal properties. In this study, the toxic effects of L. elliptica essential oil against Sprague-Dawley rat's red blood cells (RBCs) were evaluated. L. elliptica essential oil was given by oral gavage 5 times per week for 3 treated groups in the doses of 125, 250, and 500 mg/(kg body weight), respectively, and the control group received distilled water. Full blood count, RBC osmotic fragility, RBC morphological changes, and RBC membrane lipid were analyzed 28 d after the treatment. Although L. elliptica essential oil administration had significantly different effects on hemoglobin (Hb), mean cell hemoglobin concentration (MCHC), mean cell volume (MCV), and mean cell hemoglobin (MCH) in the experimental groups as compared to the control group (P<0.05), the values were still within the normal range. L. elliptica induced morphological changes of RBC into the form of echinoeyte. The percentage of echinocyte increased significantly among the treated groups in a dose-response manner (P<0.001). The concentrations of RBC membrane phospholipids and cholesterol of all treated groups were significantly lower than those of control group (P<0.001). However, the RBC membrane osmotic fragility and total proteins of RBC membrane findings did not differ significantly between control and treated groups (P>0.05). It is concluded that structural changes in the RBC membrane due to L. elliptica essential oil administration did not cause severe membrane damage. 相似文献
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A. Ravi Raja G. N. Vishal Babu Geraldine Menezes T. Venkatesh 《Indian journal of clinical biochemistry : IJCB》2008,23(2):200-203
Awareness about the toxic effects of non-essential metals is still lacking in developing countries. Lead is one among them,
which ranks second in the Agency for Toxic Substances and Disease Registry’ s top 20 lists of toxic metals. Some of the herbal
medicines prepared from certain roots and leaves are known to contain this toxic metal at alarming levels. We have a case
of a person who suffered from the toxic effects of lead such as vomiting and colicky abdominal pain after consuming a herbal
remedy for Jaundice treatment. This went unrecognized initially because of the presence of multiple problems like Malaria
and Renal calculi. Lead poisoning as causative factor for anemia, vomiting and colic were confirmed only when blood lead concentration
was estimated. A combination of chelation therapy and nutritional supplementation was found to be useful in reducing the body
lead burden. 相似文献
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Activities of human hepatic drug metabolizing enzymes N-acetyl transferase (NATS) had earlier been recognized as a cause of inter-individual variation in the metabolism of drugs.
Therefore acetylation of many drugs in human exhibit genetic polymorphism. The aim of the study was to investigate if acetylator
status predispose diabetic mellitus patients more to the complications of renal disease, One hundred and twenty (120) diabetics
consisting of (50) Type 1 (T1) and 70 Type 2 (T2) diabetes mellitus patients and 100 healthy individuals as controls were classified as slow or rapid acetylator using sulphamethazine
(SMZ) as an in vivo probe. The percentage acetylation, recovery of SMZ, creatinine clearance and presence of urinary albumin
were determined. A significant difference (P < 0.05) was observed in the percentage of SMZ acetylated between slow and rapid acetylators in control, T1 and T2 subjects. The ratios of slow to rapid acetylators for T1, T2 and control subjects were 1:4, 3:2 and 2:3 respectively. No significant differences were observed in the percentage of SMZ
recovered in the urine of slow and rapid acetylators that are diabetics. The difference in creatinine clearance of slow and
rapid acetylators in T1 and T2 were significant (P < 0.05). 29% out of 120 (24.2%) diabetics (T1 and T2) exhibited albuminuria out of which 25 (86.2%) had slow acetylator status. These findings suggest that slow acetylator status
in diabetes mellitus could be a predisposing factor in the development of renal complications. This underscores the need for
a rapid pharmacogenetic testing and therapeutic drug monitoring in such patients. However this inference could be further
validated with a larger sample size. 相似文献
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支链氨基酸与运动的关系 总被引：1，自引：0，他引：1
本文在广泛查阅相关文献的基础上,就支链氨基酸与能量代谢、蛋白质代谢,支链氨基酸与运动性中枢疲劳、外周疲劳以及支链氨基酸的毒性等方面加以综述并进行可行性分析论证。结果表明:支链氨基酸与人体运动能力关系密切,能够为长时间的耐力运动提供能量储备,促进肌肉蛋白质的合成,而且可以调节引发运动性疲劳的外周机制,推迟运动性疲劳的出现,运动后补充支链氨基酸还可以促进运动性疲劳的恢复。但至于支链氨基酸对蛋白质分解代谢的影响及其抗中枢疲劳效应,在长期训练中补充BCAA是否有减少和修复肌肉损伤的能力,是否存在性别差异以及服用大量BCAA是否对大脑和肌肉产生消极作用,导致肠胃功能的紊乱则还有待进一步的研究与探索。 相似文献
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Winegrape is an important perennial crop in California, USA. Each year California winegrape farming consumes about 20 million
kilograms of pesticides that have been a pollutant source to the fresh water systems of the state. The variation of pesticide
use among winegrape growers has been significant. It has been observed that some growers have developed effective ways to
reduce pesticide use, yet control pests efficiently to ensure harvest. Identification of the growers with low and high pesticide
use is very helpful to extension programs that aim on reducing pesticide environmental risk. In this study, an index approach
is proposed to quantitatively measure pesticide use intensity at grower level. An integrated pesticide use index is developed
by taking pesticide quantity and toxicity into account. An additive formula and a multiplying formula were used to calculate
the pesticide use index, i.e., PUI and PUIM. It was found that both PUI and PUIM were capable of identifying the low and high
pesticide users while PUI was slightly more conservative than PUIM. All pesticides used in California winegrape farming were
taken into account for calculating the indices. Madera County, one of the largest winegrape producers in California, was taken
as an example to test the proposed approach. In year 2000, among the total 208 winegrape growers, 28 with PUI≤10 and 34 with
10<PUI≤20 were identified as low pesticide users who were characterized with both low quantity and low toxicity of pesticide
use. Most of the growers had small-sized vineyards, i.e., one field and small planted areas. Furthermore, they had very low
pesticide use intensity, used only 1–2 types of pesticides (mainly fungicides), applied few pesticides (1–3 only), and emphasized
the use of low toxicity compounds. Meanwhile, 19 growers with PUI>60, identified as high pesticide users, had large-sized
vineyards, i.e., more fields and large planted areas. They used all types of pesticides and many compounds, which indicated
that their pest controls heavily depended on pesticides rather than on-farm management. Through the case study, the proposed
approach proved to be useful for analyzing the growers’ pesticide use intensities and interpreting their pesticide use behaviors,
which led to a new start point for further investigation of searching ways to reduce pesticide environmental risk. 相似文献