Abiotic stress is limiting to tea productivity. The severity and duration of the abiotic stress are critical, as it has multifarious effects on crop plants. The tea plant is commonly grown in rain-fed ecosystems and thus it encounters seasonal water deficit conditions that induce loss in crop yield. In this review, we have highlighted the effects of abiotic stress (drought, metal etc.) on the growth, mineral nutrition, reactive oxygen species (ROS), and antioxidant metabolism in tea plants. This article also highlights the mechanism of drought stress amelioration in tea plants on a physiological and biochemical basis. Drought stress caused increased water loss rate (WLR) and decrease in relative water content (RWC), dry mass, chlorophyll, carotenoid, and total phenolic contents of leaf and antioxidants like ascorbate and glutathione in tea. Leaf antioxidant enzymes (e.g., SOD, CAT, GR, etc.) showed differential activities whereas there was increase in ROS and lipid peroxidation with decreased POX activities with progressive stress. Drought stress altered antioxidative response with apparent decrease in mineral nutrient (Zn, Ca, Na, Fe, Mg, and K) contents of leaves suggesting that mineral deficiency mediated drought stress induced oxidative damage in tea. Tea plants exposed to heavy metals (e.g., Cd, Cu, Al) also showed reduction in growth and antioxidative responses. Further, a post-drought recovery study in tea also reveals that drought induced biochemical damages are not permanent, as the plant recovers on rehydration. Mineral nutrients play an important role in post-drought recovery in tea. The process of recovery was significantly influenced by foliar spray of K, Ca, Zn etc., leading to improved antioxidant potential. Thus, drought tolerance and post-drought recovery can be improved by application of nutrients like K, Ca, Zn, B etc. However, molecular mechanisms of abiotic stress amelioration and post stress recovery mediated by these nutrients need to be explored in future.
Indonesia contains a diverse range of cultures and plants. For a long time, Jamu, which is a traditional Indonesian medicine, had been used for beauty and human health in Indonesia. In this study, Indonesian medicinal plants used for skin care were examined, and the relevant information was update to incorporate anti-acne therapies. The anti-acne mechanisms included antibacterial activity against Propionibacterium acnes, Staphylococcus epidermidis, and Staphylococcus aureus, bacterial lipase inhibition, antioxidant, and anti-inflammatory activities. Most of the Indonesian medicinal plants used in skin care showed anti-acne activity that utilized et least 2 of these mechanisms. The compounds isolated from the Indonesian traditional medicinal plants related to the anti-acne activities are also discussed. In conclusion, more research on Indonesian medicinal plants is needed.
Water harvesting is a traditional conservation technique, and there is general agreement that conserving water will promote agricultural production, especially in arid and semi-arid regions. The high competition for water and land has led to scarcity of water resources, and it has also threatened the world's food security. Recent technological developments have led to improvements in rainwater harvesting techniques, which will helpguarantee the availability of food for the growing population. However, problems always occur with the implementation of any advanced technology, and this is also the case for the water harvesting system. This system, in combination with other factors, has a great potential to improve food security, especially in developing countries. This paper presents are view of more than 60 recent articles on water harvesting that were published between 1990 and 2012.
Since the discovery of renin by Tigerstedt in 1898, the complex roles of the components of the renin angiotensin system (RAS) have been extensively studied. RAS is involved in maintaining the homeostasis of body fluids and thus regulates the blood pressure. Renin is the key regulatory enzyme of RAS that catalyzes its only substrate angiotensinogen into the decapeptide angiotensin I, which is then converted into the octapeptide angiotensin II by angiotensin converting enzyme. Angiotensin II exerts its physiological effects through angiotensin type 1 and type 2 receptors. Elucidation of the three-dimensional structure of renin has led to the design and synthesis of several synthetic peptides that inhibit renin activity, controlling blood pressure. Nephrectomized animals have no detectable level of renin in their blood plasma, indicating that the kidney is the only source of renin. Renin is synthesized as preprorenin, which is processed into prorenin. Prorenin is the preactive form of renin, with an extra 43 amino acid residues that block the active site of renin. Prorenin can be converted into renin proteolytically by the action of trypsin, cathepsin, and other proteases. However, non-proteolytically activated prorenin (using acidic pH, low temperature, or protein-protein interactions) is also possible, resulting in enzymatically active renin. The (pro)renin receptor [(P)RR], a RAS member, activates prorenin through protein-protein interactions and exhibits angiotensin II-dependent as well as angiotensin II-independent functions. (P)RR in conjunction with (pro)renin exerts pathophysiological activities in human and animal models, especially in end-stage organ damage. Design of peptides that mimic parts of renin/prorenin can help to explain the binding interaction between (P)RR and its ligands. This article includes a discussion of the complex current challenges of studying renin, prorenin, and (P)RR.
The carbon dynamics of forest ecosystems are particularly significant to the phenomenon of global warming. Mangrove forests situated between aquatic and terrestrial ecosystems show unique patterns of biomass allocation and carbon dynamics, as they are subjected to daily tidal inundations and a mixture of seawater and fresh water. Due to the recent decrease in areas of mangrove forests, their carbon dynamics should be re-examined and updated. The estimation of net ecosystem productivity (NEP) is an approach for studying the carbon dynamics of an ecosystem. In this review, we performed an NEP estimation of mangrove forests in tropical and subtropical regions. The magnitude of estimated NEP was compared by two methods: the summation method and the eddy covariance technique. We found that a possible under-estimation in the summation method occurs if the belowground litter production is excluded from measurements. We also confirmed high NEP trends of mangrove forests in a comparison to upland forests. In summary, the mangrove ecosystems are considered a significant carbon sink in the tropics.
Biological monitoring using wildlife is a useful method for investigating the degree of environmental pollution. However, data obtained from wildlife cannot always be used for monitoring in some cases. One reason is that it is difficult to establish wildlife controls that are not contaminated. A new index was established for cadmium in our previous reports. Given that lead (Pb) is known to be one of the important elements involved in health problems in humans, the establishment of a similar index for Pb is also important. We selected 98 data points from 37 previous publications regarding Pb contents in wildlife samples. There was a significant correlation between the Pb contents of the kidney and liver. The above index was confirmed using previously published references including those that described Pb-contaminated birds. The data on contaminated birds deviated from the index of Pb, while the data from non-contaminated samples was observed to lie within the index. Thus, this index of Pb can be used to determine the Pb pollution status of animals and may be useful for biological monitoring.