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Fulltext Solubility of drugs in aqueous polymeric solution: effect of ovalbumin on microencapsulation process

Aziz HA, Tan YT, Peh KK

AAPS PharmSciTech, 2012 Mar;13(1):35-45.
PMID: 22101965 DOI: 10.1208/s12249-011-9707-x

Microencapsulation of water-soluble drugs using coacervation-phase separation method is very challenging, as these drugs partitioned into the aqueous polymeric solution, resulting in poor drug entrapment. For evaluating the effect of ovalbumin on the microencapsulation of drugs with different solubility, pseudoephedrine HCl, verapamil HCl, propranolol HCl, paracetamol, and curcuminoid were used. In addition, drug mixtures comprising of paracetamol and pseudoephedrine HCl were also studied. The morphology, encapsulation efficiency, particle size, and in vitro release profile were investigated. The results showed that the solubility of the drug determined the ratio of ovalbumin to be used for successful microencapsulation. The optimum ratios of drug, ovalbumin, and gelatin for water-soluble (pseudoephedrine HCl, verapamil HCl, and propranolol HCl), sparingly water-soluble (paracetamol), and water-insoluble (curcuminoid) drugs were found to be 1:1:2, 2:3:5, and 1:3:4. As for the drug mixture, the optimum ratio of drug, ovalbumin, and gelatin was 2:3:5. Encapsulated particles prepared at the optimum ratios showed high yield, drug loading, entrapment efficiency, and sustained release profiles. The solubility of drug affected the particle size of the encapsulated particle. Highly soluble drugs resulted in smaller particle size. In conclusion, addition of ovalbumin circumvented the partitioning effect, leading to the successful microencapsulation of water-soluble drugs.

Matched MeSH terms: Water/metabolism
Formulation variables affecting drug release from xanthan gum matrices at laboratory scale and pilot scale

Billa N, Yuen KH

AAPS PharmSciTech, 2000;1(4):E30.
PMID: 14727895

The purpose of this research was to study processing variables at the laboratory and pilot scales that can affect hydration rates of xanthan gum matrices containing diclofenac sodium and the rate of drug release. Tablets from the laboratory scale and pilot scale proceedings were made by wet granulation. Swelling indices of xanthan gum formulations prepared with different amounts of water were measured in water under a magnifying lens. Granules were thermally treated in an oven at 60 degrees C, 70 degrees C, and 80 degrees C to study the effects of elevated temperatures on drug release from xanthan gum matrices. Granules from the pilot scale formulations were bulkier compared to their laboratory scale counterparts, resulting in more porous, softer tablets. Drug release was linear from xanthan gum matrices prepared at the laboratory scale and pilot scales; however, release was faster from the pilot scales. Thermal treatment of the granules did not affect the swelling index and rate of drug release from tablets in both the pilot and laboratory scale proceedings. On the other hand, the release from both proceedings was affected by the amount of water used for granulation and the speed of the impeller during granulation. The data suggest that processing variables that affect the degree of wetness during granulation, such as increase in impeller speed and increase in amount of water used for granulation, also may affect the swelling index of xanthan gum matrices and therefore the rate of drug release.

Matched MeSH terms: Water/metabolism
Fulltext Catecholaminergic neurons in the comissural region of the nucleus of the solitary tract modulate hyperosmolality-induced responses

Freiria-Oliveira AH, Blanch GT, Pedrino GR, Cravo SL, Murphy D, Menani JV, et al.

Am J Physiol Regul Integr Comp Physiol, 2015 Nov 01;309(9):R1082-91.
PMID: 26333788 DOI: 10.1152/ajpregu.00432.2014

Noradrenergic A2 neurons of the nucleus of the solitary tract (NTS) have been suggested to contribute to body fluid homeostasis and cardiovascular regulation. In the present study, we investigated the effects of lesions of A2 neurons of the commissural NTS (cNTS) on the c-Fos expression in neurons of the hypothalamic paraventricular (PVN) and supraoptic (SON) nuclei, arterial pressure, water intake, and urinary excretion in rats with plasma hyperosmolality produced by intragastric 2 M NaCl (2 ml/rat). Male Holtzman rats (280-320 g) received an injection of anti-dopamine-β-hydroxylase-saporin (12.6 ng/60 nl; cNTS/A2-lesion, n = 28) or immunoglobulin G (IgG)-saporin (12.6 ng/60 nl; sham, n = 24) into the cNTS. The cNTS/A2 lesions increased the number of neurons expressing c-Fos in the magnocellular PVN in rats treated with hypertonic NaCl (90 ± 13, vs. sham: 47 ± 20; n = 4), without changing the number of neurons expressing c-Fos in the parvocellular PVN or in the SON. Contrary to sham rats, intragastric 2 M NaCl also increased arterial pressure in cNTS/A2-lesioned rats (16 ± 3, vs. sham: 2 ± 2 mmHg 60 min after the intragastric load; n = 9), an effect blocked by the pretreatment with the vasopressin antagonist Manning compound (0 ± 3 mmHg; n = 10). In addition, cNTS/A2 lesions enhanced hyperosmolality-induced water intake (10.5 ± 1.4, vs. sham: 7.7 ± 0.8 ml/60 min; n = 8-10), without changing renal responses to hyperosmolality. The results suggest that inhibitory mechanisms dependent on cNTS/A2 neurons reduce water intake and vasopressin-dependent pressor response to an acute increase in plasma osmolality.

Matched MeSH terms: Body Water/metabolism*
Hydrothermal pretreatment enhanced enzymatic hydrolysis and glucose production from oil palm biomass

Zakaria MR, Hirata S, Hassan MA

Bioresour Technol, 2015 Jan;176:142-8.
PMID: 25460995 DOI: 10.1016/j.biortech.2014.11.027

The present works investigate hydrothermal pretreatment of oil palm empty fruit bunch and oil palm frond fiber in a batch tube reactor system with temperature and time range from 170 to 250°C and 10 to 20min, respectively. The behavior of soluble sugars, acids, furans, and phenols dramatically changed over treatment severities as determined by HPLC. The cellulose-rich treated solids were analyzed by SEM, WAXD, and BET surface area. Enzymatic hydrolysis was performed from both pretreated slurries and washed solid, and data obtained suggested that tannic acid derived from lignin degradation was a potential cellulase inhibitor. Both partial removal of hemicellulose and migration of lignin during hydrothermal pretreatment caused structural changes on the cellulose-hemicellulose-lignin matrix, resulting in the opening and expansion of specific surface area and pore volume. The current results provided important factors that maximize conversion of cellulose to glucose from oil palm biomass by hydrothermal process.

Matched MeSH terms: Water/metabolism
Mechanistic investigation of phytochemicals involved in green synthesis of gold nanoparticles using aqueous Elaeis guineensis leaves extract: Role of phenolic compounds and flavonoids

Ahmad T, Bustam MA, Irfan M, Moniruzzaman M, Asghar HMA, Bhattacharjee S

Biotechnol Appl Biochem, 2019 Jul;66(4):698-708.
PMID: 31172593 DOI: 10.1002/bab.1787

Phytosynthesis of gold nanoparticles (AuNPs) has achieved an indispensable significance due to the diverse roles played by biomolecules in directing the physiochemical characteristics of biosynthesized nanoparticles. Therefore, the precise identification of key bioactive compounds involved in producing AuNPs is vital to control their tunable characteristics for potential applications. Herein, qualitative and quantitative determination of key biocompounds contributing to the formation of AuNPs using aqueous Elaeis guineensis leaves extract is reported. Moreover, roles of phenolic compounds and flavonoids in reduction of Au3+ and stabilization of AuNPs have been elucidated by establishing a reaction mechanism. Fourier-transform infrared spectroscopy (FTIR) showed shifting of O─H stretching vibrations toward longer wavenumbers and C═O toward shorter wavenumbers due to involvement of polyphenolic compounds in biosynthesis and oxidation of polyphenolic into carboxylic compounds, respectively, which cape nanoparticles to inhibit the aggregation. Congruently, pyrolysis-gas chromatography-mass spectrometry revealed the major contribution of polyphenolic compounds in the synthesis of AuNPs, which was further endorsed by reduction of total phenolic and total flavonoids contents from 48.08 ± 1.98 to 9.59 ± 0.92 mg GAE/g and 32.02 ± 1.31 to 13.8 ± 0.97 mg CE/g within 60 Min, respectively. Based on experimental results, reaction mechanism explained the roles of phenolic compounds and flavonoids in producing spherical-shaped AuNPs.

Matched MeSH terms: Water/metabolism
Effects of different doses of gamma irradiation on oxygen and water vapour transmission rate of preserved human amniotic membrane

Zahari NK, Sheikh Ab Hamid S, Yusof N

Cell Tissue Bank, 2015 Mar;16(1):55-63.
PMID: 24647964 DOI: 10.1007/s10561-014-9438-9

Preserved human amniotic membrane either air dried or glycerol preserved has been used effectively to treat superficial and partial thickness wounds without leaving any obvious hypertrophic scar. The preserved amnion, sterilised by ionising radiation, is known as an effective barrier for heat, fluid and protein loss while adheres nicely on wound. Air drying slightly reduced the oxygen transmission rate (OTR) of the amnion and the value significantly dropped after 15 kGy (p < 0.05). Glycerol preservation significantly reduced (p < 0.05) the OTR indicating less oxygen transmitted through the well structured cells of the amnion. Increase in the OTR with the increasing radiation doses up to 35 kGy possibly due to direct effects of radiation that resulted in large intercellular gaps. Both preservation methods significantly increased (p < 0.05) the water vapour transmission rate (WVTR). However, the low WVTR in the air dried amnion at 15 and 25 kGy was postulated due to cross-linking of collagen. Changes in the biophysical properties can be linked to direct and indirect effects of radiation on collagen bundles. The radiation dose of 25 kGy caused no adverse effect on biophysical properties hence it is still acceptable to sterilize both the air dried and the glycerol preserved amnions.

Matched MeSH terms: Water/metabolism*
Comparison of transepidermal water loss and skin hydration in diabetics and nondiabetics

Lai CCK, Md Nor N, Kamaruddin NA, Jamil A, Safian N

Clin Exp Dermatol, 2021 Jan;46(1):58-64.
PMID: 32619023 DOI: 10.1111/ced.14363

BACKGROUND: Pruritus is common in patients with diabetes mellitus (DM), and may lead to complex dermatological conditions if left untreated. Pruritus can be caused by increased transepidermal water loss (TEWL) and reduced skin hydration.
AIMS: To compare TEWL and skin hydration in patients with DM and controls, and to investigate associations between TEWL and skin hydration with glycated haemoglobin (HbA1c), fasting blood sugar (FBS), treatment, peripheral neuropathy (PN) and age in patients with diabetes.
METHODS: This was a prospective, case-control study carried out at a tertiary medical centre in Kuala Lumpur, Malaysia. TEWL and skin hydration measurements were taken at six different body sites in both groups.
RESULTS: In total, 146 patients (73 cases, 73 controls) were included (24 men and 49 women in each group). No significant difference in TEWL or skin hydration was seen between patients with DM and controls, but there were significant reductions in skin hydration in patients with DM who had FBS > 7 mmol/L (P 6.5% (P 1 U/kg/day (P 45 years old, there was a significant reduction in TEWL (P = 0.04) and hydration (P 8 mmol/L and increased in patients with higher insulin requirement.

Matched MeSH terms: Body Water/metabolism*
Measurement of nutritional status using conventional anthropometry and D2O in Sarawak, Malaysia

Wells JC, Strickland SS

Eur J Clin Nutr, 1996 Oct;50(10):668-71.
PMID: 8909933

To evaluate the effect of different methods (plateau or back extrapolation) of calculating total body water (TBW) from deuterium dilution in an environment characterised by high water turnover. The back extrapolation model is assumed to be more accurate when water turnover is high.

Matched MeSH terms: Body Water/metabolism
Fulltext Bulked segregant analysis for relative water content to detect quantitative trait loci in wheat under drought stress

Naroui Rad MR, Abdul Kadir M, Rafii MY, Jaafar HZ, Naghavi MR

Genet. Mol. Res., 2012;11(4):3882-8.
PMID: 23212327 DOI: 10.4238/2012.November.12.5

This study was carried out to evaluate the genetic effect of quantitative trait loci (QTLs) conferring drought tolerance in wheat. A population of 120 F(2) individuals from the cross between the drought-tolerant S-78-11 and drought-sensitive Tajan cultivars were analyzed for their segregation under drought stress conditions. The relative water content under drought stress conditions exhibited continuous variation, indicating the minor gene effects on the trait. Single-marker analysis (SMA) was carried out to detect the main QTL association with drought tolerance. The SMA results revealed that the simple sequence repeat markers GWM182 and GWM292 on chromosome 5D and GWM410 on chromosome 5A exhibited significant association with drought tolerance, accounting for 30, 22, and 21% of the total variation, respectively. The 3 genetic loci, especially GWM182, can be used in marker-assisted selection methods in drought tolerance breeding in wheat.

Matched MeSH terms: Water/metabolism*
Factors influencing the release of Mitragyna speciosa crude extracts from biodegradable P(3HB-co-4HB)

Chee JW, Amirul AA, Majid MI, Mansor SM

Int J Pharm, 2008 Sep 1;361(1-2):1-6.
PMID: 18584978 DOI: 10.1016/j.ijpharm.2008.05.007

Copolyesters of 3-hydroxybutyrate (3HB) and 4-hydroxybutyrate (4HB) were produced by Cupriavidus sp. (USMAA2-4) (DSM 19379) from carbon sources of 1,4-butanediol and gamma-butyrolactone. The composition of copolyesters produced varied from 0 to 45 mol% 4HB, depending on the combination of carbon sources supplied. The P(3HB-co-4HB) films containing Mitragyna speciosa crude extract were prepared with the ratio varying from 10 to 40% (w/w). The in vitro crude extract release of the films was studied in 0.1M phosphate buffer (pH 7.4) at 37 degrees C. Although the release rate was slow, it was maintained at a constant rate. This suggests that the crude extract release was due to the polymer degradation because the amount of crude extract released was consistent. The amount of degradation was based on the films' dry weight loss, decrease in molecular weight and surface morphology changes. The degradation rate increased with the 4HB content. This showed that the polymer degradation is dependant on the molecular weight, crystallinity, thermal properties and water permeability. The different drug loading ratio which led to surface morphology changes also gave an effect on polymer degradation.

Matched MeSH terms: Water/metabolism
Persistence and bioactivity of metsulfuron-methyl in three soils

Ismail BS, Azlizan BA

J Environ Sci Health B, 2002 Jul;37(4):345-53.
PMID: 12081026

The persistence of metsulfuron-methyl (methyl 2-[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)aminocarbonyl]aminosul fonyl]benzoate) in nonautoclaved and autoclaved Selangor, Lating, and Serdang series soils incubated at different temperatures and with different moisture contents was investigated under laboratory conditions using cucumber (Cucumis sativus L.) as the bioassay species. Significant degradation of metsulfuron-methyl was observed in nonautoclaved soil compared with the autoclaved soil sample, indicating the importance of microorganisms in the breakdown process. At higher temperatures the degradation rate in nonautoclaved soil improved with increasing soil moisture content. In nonautoclaved Selangor, Lating and Serdang series soils, the half-life was reduced from 4.79 to 2.78 days, 4.9 to 3.5, and from 3.3 to 1.9 days, respectively, when the temperature was increased from 20 degrees to 30 degrees C at 80% field capacity. Similarly, in nonautoclaved soil, the half-life decreased with an increasing soil moisture from 20% to 80% at 30 degrees C in the three soils studied. In the autoclaved soil, the half-life values were slightly higher than those obtained in the nonautoclaved soils, perhaps indicating that the compound may be broken down by nonbiological processes. The fresh weight of the bioassay species was reduced significantly in Serdang series soil treated with metsulfuron-methyl at 0.1 ppm. However, the reduction in fresh weight of the seedlings was least in Lating series soil, followed by Selangor series soil.

Matched MeSH terms: Water/metabolism
Level of chemical and microbiological contaminations in chili bo (paste)

Zaini NA, Harith HH, Olusesan AT, Zulkifli AH, Bakar FA, Osman A, et al.

J Food Prot, 2010 Mar;73(3):541-6.
PMID: 20202342

The objective of this study was to determine the level of preservatives and microbiological loads in various brands of commercially available chili bo (paste). Fifteen different brands of chili bo obtained from the local market and hypermarkets were analyzed for pH, moisture and benzoic acid content, microbiological loads (aerobic, anaerobic, aerobic spores, and fungi), and thermophilic microorganisms. Results showed that both moisture content and pH vary among samples. The concentrations of benzoic acid detected in chili bo were found to be in the range of 537 to 5,435 mg/kg. Nine of fifteen brands were found to exceed the maximum level permitted by the Malaysian Food Law in accordance with the Codex Alimentarius (1,000 mg/kg for benzoic acid). An apparent correlation between benzoic acid concentration and microbiological loads present in the chili bo was observed. The microbiological loads were found to be relatively low in the end products containing high amounts of benzoic acid. The heat-resistant (70 to 80 degrees C) microorganisms present in chili bo were identified as Ochrobacterum tritici, Stenotrophomonas rhizophila, Microbacterium maritypicum, Roseomonas spp., CDC group II-E subgroup A, Flavimonas oryzihabitans, and Pseudomonas aeruginosa, with M. maritypicum being the most frequently found (in 9 of 15 samples) microorganism. Most of these identified microorganisms were not known to cause foodborne illnesses.

Matched MeSH terms: Water/metabolism
Antibacterial activity and mechanical properties of partially hydrolyzed sago starch-alginate edible film containing lemongrass oil

Maizura M, Fazilah A, Norziah MH, Karim AA

J Food Sci, 2007 Aug;72(6):C324-30.
PMID: 17995673

Edible films were prepared from a mixture of partially hydrolyzed sago starch and alginate (SA). Lemongrass oil (0.1% to 0.4%, v/w) and glycerol (0% and 20%, w/w) were incorporated in the films to act as natural antimicrobial agent and plasticizer, respectively. The films were characterized for antimicrobial activity, water vapor permeability (WVP), tensile strength (TS), percent elongation at break (%E), and water solubility (WS). Fourier transform infrared (FTIR) spectroscopy was conducted to determine functional group interactions between the matrix and lemongrass oil. The zone of inhibition was increased significantly (P < 0.05) by addition of lemongrass oil at all levels in the presence and the absence of glycerol. This indicates that the film containing lemongrass oil was effective against Escherichia coli O157:H7 at all levels. In the absence of glycerol, the tensile strength of film decreased as the oil content increased, but there was no significant (P > 0.05) difference in percent elongation. The percent elongation at break and WVP values for film with 20% glycerol was found to be increased significantly (P < 0.05) with an increase in lemongrass oil content. Addition of lemongrass oil did not have any interaction with the functional groups of films as measured by FTIR.

Matched MeSH terms: Water/metabolism
Physiological changes in major soldiers of Macrotermes gilvus (Isoptera: Termitidae) induced by the endoparasitoid Misotermes mindeni (Diptera: Phoridae)

Foo FK, Othman AS, Lee CY

J Insect Physiol, 2011 Nov;57(11):1495-500.
PMID: 21840313 DOI: 10.1016/j.jinsphys.2011.07.019

The majority of true parasitoids manipulate their host's physiology for their own benefit. In this study, we documented the physiological changes that occurred in major soldiers of the subterranean termite Macrotermes gilvus (Hagen) (Isoptera: Termitidae) parasitized by the koinobiont larval endoparasitoid Misotermes mindeni Disney and Neoh (Diptera: Phoridae). We compared the metabolic rate, body water content, body water loss rate, cuticular permeability, and desiccation tolerance between parasitized and unparasitized major soldiers. The metabolic rate of parasitized hosts was significantly higher than that of unparasitized termites. Mean total body water content of parasitized major soldiers (64.73±3.26%) was significantly lower than that of unparasitized termites (71.99±2.23%). Parasitized hosts also had significantly lower total body water loss rates (5.72±0.06%/h) and higher cuticular permeability (49.37±11.26 μg/cm/h/mmHg) than unparasitized major soldiers (6.75±0.16%/h and 60.76±24.98 μg/cm/h/mmHg, respectively). Parasitized major soldiers survived almost twice as long as unparasitized termites (LT(50)=6.66 h and LT(50)=3.40 h, respectively) and they had significantly higher tolerance to water loss compared to unparasitized termites (45.28±6.79% and 32.84±7.69%, respectively). Body lipid content in parasitized hosts (19.84±6.27%) was significantly higher than that of unparasitized termites (6.17±7.87%). Finally, parasitized hosts had a significantly lower percentage of cuticular water content than unparasitized major soldiers (10.97±1.84% and 13.17±2.21%, respectively). Based on these data, we conclude that the parasitism-induced physiological changes in the host are beneficial to the parasitoids as the alterations can clearly increase the parasite's chances of survival when exposed to extreme environmental conditions and ensure that the parasitoids are able to complete their larval development successfully before the host dies.

Matched MeSH terms: Water/metabolism
Influence of temperature on survival and water relations of Paederus fuscipes (Coleoptera: Staphylinidae)

Bong LJ, Neoh KB, Jaal Z, Lee CY

J Med Entomol, 2013 Sep;50(5):1003-13.
PMID: 24180105

The effects of four temperatures (15, 23.5, 28, and 35 degrees C) on the biological characteristics of the rove beetle Paederus fuscipes Curtis were studied, and its cuticular permeability also was measured. Specimens successfully developed to adulthood at each temperature tested, but development time of each preadult stage significantly decreased with increasing temperature. Both egg and L1 stages required at least 80 degree days above a threshold of approximately 10 degrees C to develop to the subsequent stage. The lengthy development time and high survival rate of preadults at 15 degrees C suggests that P. fuscipes can survive in a harsh environment during cold weather by hibernating, and this ability could allow preadults to succeed ecologically in temperate countries. However, adult longevity was short, and no fecundity was recorded at 15 degrees C. At 28 degrees C, P. fuscipes exhibited a high survival rate of adults, which had a longer life span and high fecundity; thus, the population had the highest intrinsic rate of increase (0.0788 +/- 0.0051 d(-1)) and the shortest mean generation time (48.57 +/- 1.43 d) at 28 degrees C. At this temperature, the population might reach a size that could facilitate invasion into residential areas. However, in the absence of a hygric environment, P. fuscipes was unable to survive despite favorable temperature. Unlike in adults and pupae, high cuticular permeability values were found in the larval stages. This indicates that larvae are highly susceptible to desiccation, and it explains why the distribution of P. fuscipes is restricted to moist habitats.

Matched MeSH terms: Water/metabolism*
The mechanistic role of active site residues in non-stereo haloacid dehalogenase E (DehE)

Zainal Abidin MH, Abd Halim KB, Huyop F, Tengku Abdul Hamid TH, Abdul Wahab R, Abdul Hamid AA

J Mol Graph Model, 2019 07;90:219-225.
PMID: 31103914 DOI: 10.1016/j.jmgm.2019.05.003

Dehalogenase E (DehE) is a non-stereospecific enzyme produced by the soil bacterium, Rhizobium sp. RC1. Till now, the catalytic mechanism of DehE remains unclear although several literature concerning its structure and function are available. Since DehE is non-stereospecific, the enzyme was hypothesized to follow a 'direct attack mechanism' for the catalytic breakdown of a haloacid. For a molecular insight, the DehE modelled structure was docked in silico with the substrate 2-chloropropionic acid (2CP) in the active site. The ideal position of DehE residues that allowed a direct attack mechanism was then assessed via molecular dynamics (MD) simulation. It was revealed that the essential catalytic water was hydrogen bonded to the 'water-bearer', Asn114, at a relatively constant distance of ∼2.0 Å after 50 ns. The same water molecule was also closely sited to the catalytic Asp189 at an average distance of ∼2.0 Å, signifying the imperative role of the latter to initiate proton abstraction for water activation. This reaction was crucial to promote a direct attack on the α-carbon of 2CP to eject the halide ion. The water molecule was oriented favourably towards the α-carbon of 2CP at an angle of ∼75°, mirrored by the formation of stable enzyme-substrate orientations throughout the simulation. The data therefore substantiated that the degradation of a haloacid by DehE followed a 'direct attack mechanism'. Hence, this study offers valuable information into future advancements in the engineering of haloacid dehalogenases with improved activity and selectivity, as well as functionality in solvents other than water.

Matched MeSH terms: Water/metabolism
Carbon allocation in a Bornean tropical rainforest without dry seasons

Katayama A, Kume T, Komatsu H, Saitoh TM, Ohashi M, Nakagawa M, et al.

J Plant Res, 2013 Jul;126(4):505-15.
PMID: 23283581 DOI: 10.1007/s10265-012-0544-0

To clarify characteristics of carbon (C) allocation in a Bornean tropical rainforest without dry seasons, gross primary production (GPP) and C allocation, i.e., above-ground net primary production (ANPP), aboveground plant respiration (APR), and total below-ground carbon flux (TBCF) for the forest were examined and compared with those from Amazonian tropical rainforests with dry seasons. GPP (30.61 MgC ha(-1) year(-1), eddy covariance measurements; 34.40 MgC ha(-1) year(-1), biometric measurements) was comparable to those for Amazonian rainforests. ANPP (6.76 MgC ha(-1) year(-1)) was comparable to, and APR (8.01 MgC ha(-1) year(-1)) was slightly lower than, their respective values for Amazonian rainforests, even though aboveground biomass was greater at our site. TBCF (19.63 MgC ha(-1) year(-1)) was higher than those for Amazonian forests. The comparable ANPP and higher TBCF were unexpected, since higher water availability would suggest less fine root competition for water, giving higher ANPP and lower TBCF to GPP. Low nutrient availability may explain the comparable ANPP and higher TBCF. These data show that there are variations in C allocation patterns among mature tropical rainforests, and the variations cannot be explained solely by differences in soil water availability.

Matched MeSH terms: Water/metabolism*
Fulltext Alleviation of water stress effects on MR220 rice by application of periodical water stress and potassium fertilization

Zain NA, Ismail MR, Mahmood M, Puteh A, Ibrahim MH

Molecules, 2014;19(2):1795-819.
PMID: 24504074 DOI: 10.3390/molecules19021795

The use of periodical water stress and potassium fertilization may enhance rice tolerance to drought stress and improve the crop's instantaneous water use efficiency without much yield reduction. This study was conducted to assess the effects of different periodical water stress combined with potassium fertilization regimes on growth, yield, leaf gas exchanges and biochemical changes in rice grown in pots and compare them with standard local rice grower practices. Five treatments including (1) standard local grower's practice (control, 80CF = 80 kg K2O/ha + control flooding); (2) 120PW15 = 120 kg K2O/ha + periodical water stress for 15 days; (3) 120DS15V = 120 kg K2O/ha + drought stress for 15 days during the vegetative stage; (4) 120DS25V = 120 kg K2O/ha + drought stress for 25 days and (5) 120DS15R = 120 kg K2O/ha + drought stress for 15 days during the reproductive stage, were evaluated in this experiment. Control and 120PW15 treatments were stopped at 100 DAS, and continuously saturated conditions were applied until harvest. It was found that rice under 120PW15 treatment showed tolerance to drought stress evidenced by increased water use efficiency, peroxidase (POX), catalase (CAT) and proline levels, maximum efficiency of photosystem II (fv/fm) and lower minimal fluorescence (fo), compared to other treatments. Path coefficient analysis revealed that most of parameters contribute directly rather than indirectly to rice yield. In this experiment, there were four factors that are directly involved with rice yield: grain soluble sugar, photosynthesis, water use efficiency and total chlorophyll content. The residual factors affecting rice yield are observed to be quite low in the experiment (0.350), confirming that rice yield was mostly influenced by the parameters measured during the study.

Matched MeSH terms: Water/metabolism*
The ground beetle fauna (Coleoptera: Carabidae) of Kenyir water catchment, Terengganu, Peninsular Malaysia

Abdullah F, Sina I, Fauzee F

Pak J Biol Sci, 2008 Nov 01;11(21):2478-83.
PMID: 19205267

An assemblage of beetle specimens from family Carabidae (ground beetles) was carried out at Kenyir water catchment as an indicator to measure disturbance. The samplings were conducted from 30th July to 1st August 2007 at limestone forest of Teluk Bewah and the dipterocarp forest of Sungai Cicir. 28 individuals from 13 species were collected from Teluk Bewah whereas 54 individuals from ten species was sampled from Sungai Cicir. The carabids were more specious (Simpson Diversity index: 0.97) and more abundant (Margalef index: 5.35) at Teluk Bewah compared to Sungai Cicir (Simpson Diversity index, 0.72: Margalefindex, 2.22). Light trapping was most efficient assembling 97.56% of ground beetles compared to Malaise trap, pitfall and net sweeping. This is the first record of beetle assemblage at Kenyir water catchment, Malaysia. New records for Kenyir, Terengganu, Malaysia are Abacetus sp. 1, Abacetus sp. 2, Acupalpus rectifrotis, Aephnidius adelioides, Dischissus notulatus, Dolichoctis sp., Dolichoctis sp. 2, Dolichoctis straitus, Ophinoea bimaculata, Perigona sp., Pheropsophus piciccollis, Pheropsophus occipitalis, Stenolophus quinquepustulatus, Stenolophus smaragdulus, Stenolophus sp., Tachys coracinus, Casnoidea sp., Orthogonius sp. Seven species coded as Cara C, Cara J, Cara M, Cara N, Cara O, Cara R and Cara S were unidentified and are probably new species to be described in another report. There is moderately high diversity (Simpson Diversity index: 0.846) of Carabidae indicating that ecotourism does not affect diversity of ground beetle at Kenyir Lake.

Matched MeSH terms: Water/metabolism*
Expressing banana transcription factor MaERFVII3 in Arabidopsis confers enhanced waterlogging tolerance and root growth

Teoh EY, Teo CH, Baharum NA, Tan BC

PeerJ, 2024;12:e17285.
PMID: 38708359 DOI: 10.7717/peerj.17285

BACKGROUND: Waterlogging poses a significant threat to plant growth and yield worldwide. Identifying the genes responsible for mitigating waterlogging stress is crucial. Ethylene-responsive factors (ERFs) are transcriptional regulators that respond to various biotic and abiotic stresses in plants. However, their roles and involvement in responding to waterlogging stress remain largely unexplored. Hence, this study aimed to elucidate the role of ERFs in enhancing banana plant resilience to waterlogging.
METHODS: We hypothesized that introducing a group VII ERF transcription factor in Arabidopsis could enhance waterlogging stress tolerance. To test this hypothesis, we isolated MaERFVII3 from banana roots, where it exhibited a significant induction in response to waterlogging stress. The isolated MaERFVII3 was introduced into Arabidopsis plants for functional gene studies.
RESULTS: Compared with wild-type plants, the MaERFVII3-expressing Arabidopsis showed increased survival and biomass under waterlogging stress. Furthermore, the abundance of transcripts related to waterlogging and hypoxia response showed an elevation in transgenic plants but a decrease in wild-type and empty vector plants when exposed to waterlogging stress. Our results demonstrate the significant contribution of MaERFVII3 to waterlogging tolerance in Arabidopsis, providing baseline data for further exploration and potentially contributing to crop improvement programs.

Matched MeSH terms: Water/metabolism

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