A new stearoyl glucoside of ursolic acid, urs-12-en-3β-ol-28-oic acid 3β-d-glucopyranosyl-4′-octadecanoate and other compounds were isolated from the leaves of Lantana camara L. The structure of this new glycoside was elucidated and established by standard spectroscopic methods. In streptozotocin-induced diabetic rats it showed significant reduction in blood glucose level. 相似文献
This paper evaluates the changes to the green infrastructure of the megacity of Karachi, Pakistan, occurring during a period of rapid development, involving extensive loss of trees and green spaces since 2000, occurring as a consequence of road widening and improvements to the city's transport infrastructure, aggravated by a series of cyclones, involving further tree loss and which has led to numerous ecological problems in the city, assessing how the effect of the reduction of Karachi's green infrastructure has impacted both the reality and the perception of human health conditions. It uses medium-resolution satellite images classified for land use and land cover (LULC) data extraction and detailed field surveys to map the extent of change; structured questionnaires are used to identify the perception of selected, targeted groups regarding the state of Karachi's urban green infrastructure and perceived human health conditions. Findings indicate that the public perception of green space functionality or presence does not equate with the remote sensing and field mapping results, which show a dramatic loss. The need to develop a comprehensive urban greening strategy, which considers the needs and priorities of the population, is identified. The impact of such a strategy in terms of increased frequency of visits to green sites and associated increase in the physical activity of the people to improve overall physical health is discussed in relation to the general development of Karachi. 相似文献
Herbage growth and nitrogen (N) use efficiency in grazed or mown grasslands are generally low, associated mostly with poor response to fertilizer N. The aim of the present investigation was to examine the short-term response of grass to fertilizer N with respect to herbage yield and nitrogen use efficiency (NUE) in order to provide a better basis for improving the efficient use of fertilizer N in grassland ecosystems. Both NO3? and NH4+ sources of N were applied to an established grass sward with three moisture levels, i.e., natural conditions (63% water-filled pore space, WFPS), near field capacity level (71% WFPS), and slightly wetter than field capacity (84% WFPS). Herbage yield, i.e., dry matter (DM), N uptake, N recovery efficiency, yield efficiency, and physiological efficiency were determined over a 7–28 d period. Addition of N fertilizers significantly increased the herbage yield and N uptake of grass sward over that of the control. In the plots where NO3??N was added as the N source, DM yield was between 1760–1870 kg ha?1, N recovery efficiency was between 24%–43%, and yield and physiological efficiency were in the range of 2.1–3.2 and 6.4–8.8 kg DM kg? 1 N, respectively. In NH4+?N added plots, the DM yield was between 3190–3700 kg ha? 1, N recovery efficiency was between 39%–48% while yield and physiological efficiency were in the range of 3.5–5.6 and 9.0–11.6 kg DM kg? 1 N, respectively. Results indicated that total DM yield, N uptake, and NUE depend on the source of N and the level of moisture in the field. Assimilation of N is also affected by the stage of plant development after N fertilization. About 50%–54% of applied N was recovered in the initial 14 and 21 d after fertilizer application and thereafter translocation of N slowed. A fall in herbage production and minimal response to N fertilizer has been observed at 84% WFPS, while the maximum herbage yield and N recovery efficiency was recorded in soil near or below field capacity. The grass sward with added NH4+?N produced a larger yield and had higher NUE relative to the sward with NO3??N. Results confirm that applied N was not utilized efficiently by grass sward and a decrease in N uptake and its utilization seem to be the key factors responsible for the poor herbage productivity often observed in pastoral agriculture. These results suggest that both moisture and N source have a substantial effect on herbage yield and N utilization by plants and therefore should be considered for efficient management of N fertilization and recommendations for grass sward. 相似文献
The Neotropical palm infesting whitefly, Aleurotrachelus atratus Hempel (Hemiptera: Aleyrodidae) is a highly invasive pest that was reported during 2019 on coconut in India. In a short span of time, it spread rapidly across states of Karnataka, Tamil Nadu, Kerala and Andhra Pradesh on coconut, oil palm and many other ornamental palm plants. During the recent survey, the immature stages of A. atratus were found parasitized by an aphelinid parasitoid, Encarsia cubensis Gahan (Hymenoptera: Aphelinidae). These parasitoids were identified by their morphological characteristics and also characterized by DNA barcoding of adult parasitoids using partial (658 bp) mitochondrial cytochrome oxidase 1 (CO1) gene (GenBank accession number ON881119). This is the first report on occurrence of Encarsia cubensis as primary parasitoids on A. atratus in India and its natural parasitism ranged from (46–68%) on coconut across the different locations in Karnataka. It is believed that the parasitoid likely entered India along with A. atratus in India and constitutes a potential biological agent against A. atratus. It is expected that the E. cubensis population will become fully established, increase, spread and exert a significant impact on A. atratus population in India. Therefore, efforts may be made by growers and other stakeholders to increase the rate of natural parasitism through inundative, conservation and classical biological control approaches to reduce the pest population, crop damage and yield loss.
A new steroidal derivative, urs Stigmast-4, 20 (21), 23-trien-3-one and other four compounds were isolated from the leaves of Bryophyllum pinnatum. The structure of this new steroid was elucidated and established by standard spectroscopic methods. Carrageenan induced paw edema model was used for anti-inflammatory and acetic acid induced model used for analgesic activity. This new steroidal compound was found to be active in reducing inflammation (% inhibition 87.29 and 84.45 respectively) when compared with diclofenac. Further, it showed 75.72% protection in analgesic activity in acetic acid induced writhing test in mice. In conclusion the % inhibition against carrageenan induced rat paw edema and % protection against acetic acid induced writhings showed by new compound revealed that the anti-inflammatory and analgesic activity of aqueous extract B. pinnatum are mainly due to the presence of this steroidal compound. 相似文献
The parietal-eye photoreceptor is unique because it has two antagonistic light signaling pathways in the same cell-a hyperpolarizing pathway maximally sensitive to blue light and a depolarizing pathway maximally sensitive to green light. Here, we report the molecular components of these two pathways. We found two opsins in the same cell: the blue-sensitive pinopsin and a previously unidentified green-sensitive opsin, which we name parietopsin. Signaling components included gustducin-alpha and Galphao, but not rod or cone transducin-alpha. Single-cell recordings demonstrated that Go mediates the depolarizing response. Gustducin-alpha resembles transducin-alpha functionally and likely mediates the hyperpolarizing response. The parietopsin-Go signaling pair provides clues about how rod and cone phototransduction might have evolved. 相似文献